C10_Automotive Vehicle (S1-24_AELZC441) - Prof. Sajeeth Kumar.docx

Automotive Vehicle (S1-24_AELZC441) - Prof. Sajeeth Kumar-20241019_133027-Meeting Recording

October 19, 2024, 8:00AM

1h 56m 16s

SAJEETH KUMAR . started transcription

SAJEETH KUMAR . 0:08
This is right.
Can someone just reconfirm what was the last topic that we saw?
And you know, in just the basics, right. OK, great.
OK.
So today has been a marathon session of sorts for me.
Lubricates, OK.
OK, so I think this is what we did, right? We were discussing about the the fundamentals of lubricants, engine oils, difference between mineral and synthetic oil. We were just speaking about that.
So today I think we can we can go a little bit into detail and we can kind of talk about what is this particular thing 5 W 3010, W 50, we can just pay a little attention to that and.
We should also be able to understand.
Different.
Engine oil manufacturers. Different brands are there sometimes when you go to the service station, they say no, you can't use this particular brand. You have to use only this one. If you have a Volkswagen, then I think they ask you to stick with.
I don't know kestrel, that's what they they they recommend.
Some other companies they recommend Shell and some say that you cannot buy mobile one. You can't use. Synthetic oil will not give you warranty.
There's quite a lot of these things which happens also, so the idea today is to understand what these numbers means, right and.
What exactly we need to know about it. OK, so First things first. I know pretty much every one of you. If you have a 2 Wheeler or a car, you would be using something like 10 W 40, right?
Or 5W30 so you would have.
Lot of engine oil brands and engine oil specifications like this. So now the idea is what does these numbers mean? Do they actually impact your you know your vehicle operation, your engine operation and what is the information that you should know about. OK. So in order to understand that you should first understand the nature of any oil.
Not just any engine oil, but any oil you would have seen coconut oil.
Right. Especially if you come from a place like Bangalore or or Ooty or or something really cold places. You know that coconut oil literally becomes a solid when you wake up in the morning and you look at it. I don't know how many of you have noticed it right either coconut oil or a typical use case. I mean typical example would be you know your ghee, right, the ghee, what you use for food.
So you know that in colder climatic conditions you would actually see it as.
A thick solid. But whereas when it comes to hotter climatic conditions, nothing like that, it's always liquid, right?
Being in Chennai, oil is always liquid. I have not seen coconut oil in any other form, but every time we go back to our house in Wayanad, coconut oil cannot be poured. Coconut oil has to be taken in a spoon, right? I'm not joking. We take it out in a spoon and we put it on top of a flame. It it? It kind of liquidifies and then we take it, take it and we use it for.
You know, using it on your hair or or whatever it is that that's basically how we do. So it is, it is very much true that oil when it is cold, it can actually get solid, right. And when it heats, acid gets heated, it becomes thinner and coconut oil or any cooking oil for that matter. If you really heat up your skillet, it vaporises right. So now.
Take that perspective, apply it to engines. OK, now imagine if your car is parked outside. It's 10° outside. What would happen if your oil solidifies?
It can happen, right? What would happen if your oil's already phased? Have you ever thought of that happening or let me put it in another perspective?
I will write down one particular oil here. You guys tell me like if you can actually use it inside the engine, right. So Castor oil.
Why not coconut oil? Because coconut oil is too thin. It'll not work. It'll vaporise. Let's leave it out. But have you ever thought if you could actually use Castro oil in engines? What do you think will happen if you use Castro oil in engines?
So what do you think will happen if we use Castro oil in engines?
Do you know of any engines where Castor oil is used for lubrication?
Have you come across any application where testoil is used right castroil as engine oil, right?
I think.
If I'm not wrong, we used to do this a long time back, so you have Nitro engines, right? I mean, I don't know if you guys are into that scene, but are you aware of what a Nitro engine is?
Have you seen a Nitro engine? So these are not large engines. These are small engines, so these are engines which we use in RC cars. We use it in RC planes. These are very small engines, extremely small 2 stroke engines, right? 610 horsepower per litre basically means this engine has got 10CC or 5CC and it's producing some X amount. So they're basically extrapolating it but.
These are extremely small engines, right? We use it in RC cars and things like that.
And for these engines we use Castrol, right? I mean, it's arc engine for all that matter. So it doesn't have too much of things, but we use castroil and we also use nitromethane as the fuel. But there are petrol RC engines also. So the point is whenever we think about an engine oil now the engine oil is having to go through extremes of conditions, right.
So now let me write the extreme conditions so the engine is very cold, right? Let's say that the outside temperature is -20°C.
No, this is not something like I'm I'm talking about a hypothetical situation. It can actually happen if you take your car, you go to Leila Doc, right?
It is very much possible that it can hit -20 or let's leave out minus right. Let's leave out. Minus, let's look at 0°C. Do you think it is possible? I think definitely yes. You go to Ooty during winters you will see five degrees, 6°, right? So it is very much possible. So on the extreme conditions it can become 0° on the extreme hot condition.
Suppose let's go to. I mean we don't have to go to Rajasthan or somewhere even our normal cities, right? I mean, during heat waves, we see temperatures of 40°C. Maybe it can go up to 50°C right? Now think of two extreme cases of climatic conditions. OK now.
The low risk.
Yeah, vellore. Yeah. Vellore or Thirteng or yeah, Hyderabad.
If you're there, like Hyderabad gets really hot as well, right?
Chennai is not all that far fit. It is also something similar. Yeah. So you can have extreme cold. You can have extreme hot conditions. So now imagine what an engine oil has to do, right. So now add 0°. Also, it has to remain liquid, right? And most importantly, it has to flow.
It should not get solidified similarly 50°. Also it has to be liquid.
And it has to flow.
So now you're not thinking about just flowing, but it has to be viscous enough.
Right. So why do you want it to be viscous? Because if something becomes water like at 50°, then it's not going to lubricate, so the viscous property of oil is basically what provides lubrication. So now you look at the conundrum. OK, so now if I want to have a liquid or an engine oil which is basically able to remain as liquid at 0°C, OK.
What will end up happening is at if it is remaining as liquid at 40 at 0°, when it goes to extremely high temperatures 4050.
It might start vaporising.
Right. That is how it'll be. It'll start vaporising. On the other hand, if you have a engine oil which is basically liquid at high temperatures, when you come into colder climatic conditions, it will become either more viscous, right or worst case scenario, what worst case scenario it can even solidify.
Right, so now your ideal engine oil.
It's like finding the perfect car. It has to be powerful. It has to be fuel efficient, right? Conundrum. It's it's. What do you call it? Catch 22 situation right or an oxymoron. So you need to have an engine oil, which is basically liquid enough at lower temperatures and maintains almost the same temperatures at higher temperature also. So you want to have a 2IN1 oil. Now, this is possible.
When you take two different oils and you kind of.
User use a chemical compound which will alter the property of the oil so it behaves like both the things right. It's like a good cop, bad cop. So what happens is at colder climatic conditions this engine oil will act like a low viscosity oil, right? So a low viscosity oil. What will happen is even at low temperature conditions.
Low viscosity oil will basically like flow.
Right. It's almost like water, right? Water at, I mean, not water, but maybe ethylene like call plus water. Even at -30°C, it remains as liquid it flows it maintains viscosity.
Whereas at high temperatures right here, what we do is we take an oil probably like Castor oil or something, which is even more thicker than Castor oil, which even at 50° it will still maintain its viscosity, right. So what we have to do with engine oil is that we cannot use any single oil in the engine like your Castor oil or coconut oil or vegetable oil. We cannot use one single oil.
So we start with the base oil, which is a petroleum byproduct. We take that oil.
And we add some emulsifiers. We add some property, changing chemicals. Don't ask me what exactly, I don't know, but we add some property modification chemicals so that at low temperatures it will act like a low viscosity oil. Now the viscosity we use a term called weight.
Right. We call it as W for short. So a 5W oil is very, very lightweight oil, right? Whereas A50 W Oil is a very.
50 weight oil is a very thick oil. So thick oil means more viscosity. Low weight oil means less viscosity. OK, so now what we have to do is add some chemicals into it and we mix the oils in such a such a you know way so that.
We have an oil which will behave like a 5W oil at 0°C and it will behave like A50 way, toilet 80 or 100°C. So now this concept is called as multigrade engine oils.
So multigrid engine oils are what we use in engines.
For multigrade oils or what we use in engines now, if that is the case, is there any place where we use a single grade oil?
Do you know any applications where we can use a single grade oil and getaway with it? Maybe in automotive itself? Have you ever seen an application where instead of using multigrade oil we can use a single grade oil?
Tractors. No, I am not very sure. I'm not very sure, but usually single grade oil. What we can do is we can use breaks. Yep. Breaks is one thing. It's a single grade oil. You can also use it for hydraulic systems.
So hydraulic systems will usually use A50 weight oil. You can use it inside shock absorbers.
Right you use A58 or A10 weight oil.
If you guys have, you know, a bike like an R15 or something, sometimes what we do is, yeah, steering systems, the older hydraulic power steering's we'll use single grade oil. So the shock up servers and bikes, right.
Usually what happens is sometimes the the bike would be extremely stiff to ride right.
One classic example is if you have, I mean I think the duo Honda deal. If you have driven it, it is extremely stiff, tuck, tuck tuck it goes crashes and it's not very comfortable thing to drive. So you take it to the local market, what they're going to do is they're going to recondition the shock up server. So they say reconditioning the shock up server.
What they do is they open it, remove the thicker oil, they pour lightweight oil into it, right? So the point is, when it comes to engines, since they operate at extreme conditions, we need to use.
Two different, you know, two different oils, but since we can't use two different oils, what we use is we use one single oil which has got two different properties. So these are called as multigrade engine oils. So now you can take a screenshot of this if you want. I'm just going to erase it.
OK, So what exactly is a multigrid engine oil. So a multigrid engine oil is something where you define how the engine performs at colder climatic conditions. And the second part of the multigrade oil, it tells you how the engine performs at higher temperatures. So now a single grade oil will just be called as SAE 10. SAE 20 SAE 30. So that is basically how it performs at.
You know, at at at its operating point which is 100°C, whereas when you use a multigrade oil specification W.
Right. So then what happens is you have an oil which is tested at 0°F, which is -18°C and you also have it tested at the hotter climatic conditions, which is gonna be at 100°C. So lightweight is less viscous. Yes, think of coconut oil versus Castor oil. So coconut oil, I think 1 litre of coconut oil will live way lesser than one litre of Castor oil, right? So that's the idea.
So we need to have an engine oil which can kind of perform better at both the conditions.
How does it actually apply to us? Suppose you have a vehicle which is being produced for Indian conditions. OK, suppose you have a. You have something which is produced for Indian conditions or subtropical conditions. For that matter, what is the minimum and maximum temperatures that you would probably see right? So minimum temperatures we'll see is gonna be like 10° or something.
And maximum temperatures maybe 4050°. It's not gonna get extremely hot, so maybe 40 or 50° is maximum what it can do and the manufacturer would also do a lot of testing.
And they would say, hey.
10W30 this is sufficient for me to use in this particular vehicle, so then you might ask if the temperature can go to 50°C, should I not use 10 W 50? The idea is that 10 W 50 does not mean the oil performs at 50°. It's basically telling you how thick the oil is. Now if you have a low power application.
Right. And it is a non turbocharged application, right? So then what we would say is that OK on the lower #10 W is good but on the higher side since my engine is not experiencing any kind of extra pressure or stress or it's not being driven on the track, it's a it's a Maruti Alto. I can specify 10W30.
Right. Let me just go ahead and check what is the the engine oil for an Alto, right, engine oil for Alto.
Let me just check what is the give me a second.
Right. So is this what it is? OK, it says 5W40 synthetic, but I'm pretty sure they don't use synthetic on it. 5W30 right?
5W30 is what they are recommending now. If the same thing I were to check for Scora vRS 2:30, right?
They are probably gonna be using, I don't know.
Let me just check, I mean, I just wanted to, there's a is the engine oil, I've gone into something totally different.
This is basically coolant, OK?
OK, it says 5W30 EFS right? So OK, there is something 5W40, right? So let's get back here. So basically what we are finding is that for Alto they are saying 5W30. And for a Skoda Octavia also they are saying 5W30.
Now this kind of like is is pretty weird because this is not what we imagined right? So we imagined that if it's a high performance vehicle then it should at least have 5 W 55 W 60 because hey, it's it's gonna like basically like work at very high temperature conditions or it's gonna be working at extreme conditions. Right? So the idea is that this SAE rating of.
Multigrade engine oil is just one part of it. OK, so you cannot choose engine oils only by looking at 5W3010W30. You cannot do that. But this will tell you what is the you know the way of operating.
So now suppose I have 10W30. Let's assume this is what we are using. Now let's assume that I'm gonna be using this vehicle.
Primarily in the Leh ladak areas. I'm I'm I know that I'm gonna use it only over here. So then if I'm I'm more concerned about the lonitivity of the engine or working there or if I know that I'm gonna go even further up. I'm gonna operating only at high altitudes. Maybe it's it's it's an army vehicle or something. So then what I can do is I can probably switch over the engine oil.
I can go to 0 W 30 right? I mean if I mean they don't sell all possible combinations, there are only certain combinations which are available. But I can actually go for much more colder grade. So when I go with a 0 W oil, what it basically means is that when the car is at a lower temperature, right when the when the when the engine is at a lower temperature this oil will still remain liquid enough to kind of flow everywhere and lubricate things.
So the problem for us is if an oil gets too thick at colder climatic conditions, it might not flow immediately. It will wait until the engine is warmed up. It will wait until the oil has warmed up and then it starts offering proper protection to the engine systems. So if we know that deliberately there is a condition where we have to run it at colder climatic conditions, we might actually shift over to 0 W 30.
So now the question is, is there a problem if you take a car which runs on five W 30, convert it to 0 W 30? Nope, absolutely no problem. But if I take a car which is running 5 W 30 and convert it to maybe 20 W 50.
Will this have a problem? It will definitely have a problem during cold start conditions because at colder start conditions A20 weight oil will be thicker than 5 weight oil. Which means when you immediately start the car, oil will not start circulating. It will take some time for your engine to warm up and then for it to circulate and then move on. But if if you're basically like looking at a application where you don't want to wait and do that, then you'll have to make sure that that particular grade is maintained.
High temperature is meant for environment or engine itself because yeah, so high temperature grading is is is for the way that the engine is operating, right? So now let's think of what is the difference between a 30 way toil and A50 weight oil. OK so 30 weight oil and 50 weight oil 50 weight oil will be more thicker at higher temperatures. Right. So let's take 100°C. The testing temperature at 100°.
This would be.
Dinner.
And your 50 weight oil, correct.
Now, what happens when an oil is thinner than another grade of oil? So what it what it basically means is that if your engine is consistently operating at that particular high RPM areas or high performance areas, there is a chance that your 30 weight oil might breakdown. Have you ever seen?
Coconut oil vaporise on your tawas and things like that. Similar to that, if you take a 5W30 engine oil and you continue running that vehicle at extremely high.
Rpms. If you run it at extremely high performance areas, let's say you're going racing, you're driving it at that particular high RPM conditions for one hour at a stretch, then the 30 weight oil might not be sufficient. The oil might start vaporising the oil. Might not lubricate your components properly. It might lead to a degradation in the engine life.
So if you know for a fact that your engine is gonna be subjected to such extreme conditions on the higher end, you can go with the higher weight oil similarly.
If you know that the only time you will want the low temperature is like whenever your engine is operating under such conditions. If you know that your vehicle is going to be operating at extremely low temperature conditions, then it might make sense for us to go with the 0 W oil OK.
SA30 means SA 30 basically means.
At 100°C.
Right. It is having some certain parameters and it's got certain viscosities which is lesser than an engine oil at 50 weight. OK.
So.
To to kind of consolidate it, a thinner oil basically means thinner oil in the sense at the SAE right. This is the first part, and there's the second part. So in the first part, if you have a lower number, so then it'll have better call start conditions. You'll have better fuel economy. How would you have better fuel economy because oil is not too thick. If oil is too thick, then there'll be no more frictional losses. There'll be more viscous losses. So.
Technically, if you're using 5W oil versus 20 W Oil, 5 W Oil will give you better performance. I mean better fuel economy. Similarly, a thicker oil, right, thicker oil at higher conditions. The second part of it it provides improved protection at higher temperatures, but albeit when you come into, you know the the viscosity since the viscosity is going to be higher.
The fuel economy is going to be less.
So if you are still wondering what is the relation between engine oil and fuel economy, you need to go back and.
Revisit this architecture.
Get with me.
You need to revisit this architecture. So now remember in this architecture the crankshaft is over here and the oilsump is over here. But actually this is not how it is over here. For the diagram they have done it like that. But when you assemble the engine what will happen is the oil sump will kind of come like this so which means this lower portion of the crank.
Is completely submerged in engine oil.
It's going through the engine oil now imagine you walking through water in a pool, right? You know that it is difficult than walking outside, right, walking through a pool is difficult. Now imagine if that water is replaced with oil. How difficult will it be for you to walk through that oil? Now imagine that oil instead of coconut oil. Maybe you're replacing it with crude oil or slush.
You know you have slush and things. You know how difficult it gets, right? Or extreme conditions. You have quicksand, right? You cannot literally move through it, right? It it becomes really solid. And and it did something like that non determined fluid kind of a consistency it'll have.
So this is the reason why when you have a thinner oil, you get better fuel economy because the crankshaft is able to move through it easily.
When you have a thicker oil, it takes a little bit of effort, but let me again reiterate it when I say better fuel efficiency and all of those things, it is relatively speaking. So will I have a difference of two kilometres 3 kilometres per litre? Maybe not two or three kilometres, definitely. Maybe point 2.5, something like that. You would definitely see differences.
Now remember I said on one end we had the Maruti Alto with the 5W30 rating.
And we had a score of Octavia. We are is also with the 5W30. So the Alto is a 800CC45 BHP engine and these vehicles are usually 2000CC.
They run with a with a basic remap. These cars can run 240 BHP.
Right. So it's it's kind of like for almost let's say close to 3 * 3 times the you know.
Engine CC-8 threes are 24, so maybe 2.5 times the CC you have six times the horsepower, right? So which means the engine on the Octavia is going to be really stressed. Of course it's turbocharged, but even in those cases they're using the same grade engine oil.
Isn't that counterintuitive? Shouldn't we use something like 5 W 50 or something like that? That's what I meant.
This basically tells you only one part of the story. The grade is just one part of the story, apart from the grade, there is also a rating of the engine oil. Now this rating will be done by multiple different organisations depending on where that particular engine oil brand is originating or it can be requested by the vehicle manufacturers.
Depending on where they are, press it now. If you have a manufacturer who's based out of America like Ford or General Motors or Chevrolet, they will request for a API rating. API stands for American Petroleum Institute, so they are bound to use that. So an API rating will have two components, so it'll have something like SN, CN, something like that. So yes.
Stands for gasoline or petrol engines. C stands for diesel engines, so they'll say that, OK, this particular engine oil is manufactured specifically for, let's say, gasoline or diesel engines.
And then you have something called as a.
Quality rating. So N is the quality rating, so an engine oil, an engine oil grade is one part and the next part happens to be the grade of the engine oil. So the grade, if you look at it here it says yes and SM. So basically these are quality ratings. So you can think of it as your.
Your grades in in probably like your.
Grades in your in your exam, so you have a Grade B, grade C grade A is better than C, right? Something similar to that. So if Skoda might say hey, I need an API yesm rating or let's say I need an APASM rating there is your your.
Alto or something would say I need only API say ESP rating, something like that right? So they might have a lower rating. They might have a higher rating so your engine oil should be capable of also meeting this API rating.
But in API rating, the idea is that if you take an oil with a higher rating, you can use it for a lower rating. So idea is if it is 5W30 engine oil you buy an oil which is meant for a score of Octavia. You pour it into an Alto, it will still work. Why? Because the the grade is the same quality rating. Skoda has got much more higher rating. So obviously it will meet whatever requirements are there for the lower levels.
It's like me saying if you wanna enrol for my class, you should have an 8.5 CGPA, right? Or OK, maybe 5.5 CGPA.
So does that meet someone with an 8 CGPA? Can enrol of course he can right? So it means that he's already meeting this and he's exceeding it. In fact, so I can use an oil which has got a higher rating on a vehicle which needs only a lower rating. But I cannot do vice versa. There is also one more important thing and this is something. I mean I don't know if you guys do that right. So what some people say is.
They'll buy a car for ₹1,00,000, right? ₹1,00,000 maybe some old car and they'll go. They'll buy a spark plug from a Ferrari and they'll put that spark plug in there. Car.
Now, does that mean that your card will have higher performance just because it's got a Ferrari spark plug? Nope, it's not right. So what you need for every particular vehicle, it's it's kind of like depending on.
That system's performance. So if all you need is a 5.5 CGPA, you can have someone with an 8.5 CGP in it. But does that mean that it'll make any difference to the system per SE? No.
It does not, right? So now let's look at what this API rating is, right? So API stands for American Petroleum Institute. So they basically rate engine oils on S&C. Yes, for petrol and C for diesel engines. And they also have quality rating starting with M and PS and and things like that, right.
Now the same thing. If you were to go to Europe, right, they are more likely to use the ilsec, right? So I'll sack is something which stands for international lubrication standardisation.
And again, they have their own like specifications, their own testing methods. So the same 5W30. It will basically come with an lsac rating.
Does it mean that API is better? I'll sack is better. No, nothing like that. It just you're having different testing standards.
How many of you? How many of you here drive a two Wheeler?
Likes more specifically, how many of you here drive bikes? If you drive bikes, you have helmets, right? And what is your favourite helmet brand?
Or what is your dream helmet brand?
Bigger.
That's OK. I was expecting a different answer.
LS2, OK. You like to go a little bit higher? How many of you would like to have an AGV?
Exawatt is good.
Maybe an AGV?
Right. Or you have Bill, right? I don't know if you have heard of it, but bill, helmets are what we use for racing, right? We use Bell helmets for that. And trust me, this is the entry level. What you're seeing here. Alpine. Do they have helmets? I don't know. Right. So these are these are basically just the entry levels that you're using.
If you are a are a car freak and you, you.
No. What is it? OK, Daemon tweaks, right? So if you if you are someone who likes cars and you, you you want to kind of like dream. It's it's like, I mean you don't take me wrong but there's there's like kind of like wet dreams. Like what would I what would I do if money was no object for me.
This is what I do. I go, I check on things here and you can just multiply this by 100, right?
You look at this carting helmet, this is 73 thousand 1,17,000 right so.
I mean, these are these are motorsport car helmets. When you go into bikes, especially if you use sports bikes, the heavier helmets will kind of put stress on your neck, right? You cannot drive it for long crouched. And also you go for these lightweight helmets. But the case in point, right, the case in point is that.
Do you know that an RI helmet, right, which comes with a dot ECE certification, which is basically homologated for using in Moto GPS?
You know what a Moto GP race is, right? For those of you who are not aware of it, Moto GP is like the Formula One for bikes. It's the it's the top bike racing championships you have GP2GP3 there. There are multiple classes, but it's it's like the FAA sponsored motorcycle racing. So you could have a helmet, which is basically rated for that kind of a motor sport applications, but.
You cannot use it in India.
Right. Trust me, you get those helmets, and if you try going on the roads, if the cops catch you, they will find you.
I'm not joking. This has actually happened.
Via files, a lot of public interest petitions or public interest Litty PAL, right? Whatever it is, we've filed it in court.
We collected some signatures from from 506 hundred people. We signed it and send it all because as far as the RTO in India is concerned, your helmet needs to have a ISI mark. If you do not have an ISI mark on your helmet, you are basically getting fined.
So imagine you bought yourself a Ducati. You've gone and bought yourself an RI helmet for ₹75,000, which is good enough for you to go drive a Moto GP race. You drive it inside the roads on India, they will catch you because they'll say it does not have an ISA mark, right?
No, Rhode Island does not do it for this it it comes under ISA. So it's a different standards body which tests that Rhode Island basically does not get into it. I mean it's it's, I mean it's plain stupid, right? I mean, I'm I'm sorry if it comes out wrong, but it's plain stupid.
On one side you have something which satisfies a much more higher quality levels, but when it comes to.
OK, there are two different things. Let me check. Yeah, it should be like Ile A/C not I SLACI think I ELE A/C. There's a spelling mistake here.
I think it should be.
OK, doesn't really matter. Somewhere it has changed, doesn't really matter, but just understand there are multiple things like this. So the point is that it's not about what exactly that certification means, but manufacturers would tell you, OK, this is what we need to use in our car. We have tested it with it. So if they have tested it with it, you will have to use that particular engine oil.
OK, so this particular thing I've picked it up from the diagnostics class which we run, so there's not a bit specific one. I've just added it here. So there is the not spell checked it, there is some mistakes in this but.
Please, please do excuse me for that, but the point is there are multiple organisations and every single person will kind of specify a different standard. Now moving on there is a European rating systems right? I think this is called a CEA. They also have similar for gasoline and diesels. They have diesels with DPF without DPF and they have a whole lot of other categories.
Does it stop there? If no it does not because there is Japanese ratings also, right?
Again, Japanese ratings. It's called Jaso. There are their own standards, but usually what ends up happening is that whenever you pick up engine oil, right. So when you look at it here, so you will find that this confirms with forward WSS something. So forward has got its own internal quality. Volkswagen will have its own internal quality ratings so usually.
What happens is depending on which part of the country that you're developing it, they have their own benchmarking standards. But.
Thankfully, with engine oils, they also benchmark it with OEM standards, so the OEMs will approve it or what will happen is like say if in India like.
There is a new company called Enios right Enios is not approved by any OEMs anywhere but in India. Enios will go approach the manufacturers. They'll say please test it and tell us like if you would approve it and then they'll give a letter saying Maruti approves Enios engine oil for meeting or exceeding all standards. So then Enios will come and start like marketing it. So this is basically how it happened. So you have standards. These standards will kind of tell you what is the oil quality.
So now do you have to remember all this? Not unless you happen to be in tribology or you know someone who's working with it. You don't have to. But understand that there is differences in the engine oil.
Not just on the grade, but also based on the quality. Now one very important change which has happened in India is that we've had this, you know, the BS6 norms which came in and when BS6 came in, we started having low sulphur diesel desulphurized diesel or low sulphur diesel, right. So diesel's they have.
No sulphur in it, so earlier sulphur used to be lubricating agent, so the fuel per SE had sulphur dissolved in it and that sulphur will kind of give some lubrication.
But right now we have engine oils which do not have sulphur in it. Right? So now when BS6 came in, we needed to have BS6 specific engine oils. We also have diesel particulate philtres and we also have Scrs selective catalyst, three generation systems. So then engine oils were reengineered to be compatible with DPF and SCRS so.
We have a lot of formulations like that. So now if you have a vehicle which is ABS 6 vehicle then more often than not you will have to kind of stick to it. So ideal case is that you just stick to what the manufacturer has said. It works fine but in some cases if you go one or two grades higher it's not gonna do any harm. It might be expensive, it might not produce any benefits, but at least it will not do any harms, right?
So now what are the additives that we use? We add additives like you know you can just read it out through. So you have additives which modifies the viscosity. This is basically the multigrade oil, whatever I was talking about.
They have oil additives which kind of like improve the forming properties or reduce the forming of the oil because if engine oil forms then it's going to have, you know, very poor lubricating properties. So you have various other auditors which are being added all of this.
Kind of like you know.
Improve the performance of your engine O it so when you have an engine oil coming from a company like mobile one. So there's been decades of R&D which has gone into it. They don't even specify what chemicals they use or how the chemicals are being, you know prepared or anything but you just know that this is basically going to help your oil become better, right? This this this completely.
You know, basically like from a additive perspective, it's just pure theory. You can just read through it now moving on we have.
The synthetic oil versus mineral oil, right. So the idea is that the synthetic oils, these are basically like.
They are. They are manufactured, right? So they have a lot more of additives which goes into it. So the idea is that a synthetic oil will have better characteristics than your mineral oils. Mineral oils will probably cost you 150 to ₹200 a litre, whereas fully synthetic oils can be as high as thousand ₹2500 a litre.
So the idea is that when you use synthetic oils, they have much more better performance in terms of, you know your your, your engine lubrication and things like that. So there is one, I mean you don't have to worry about these things, right? You don't have to worry about these things. It's just there for just for information. So just talks about what are the vehicle manufacturer standards you know.
Like what I said, maybe we'll just skip it out with this. Yeah. So, 11 very interesting thing is that how do you find out if you're being sold a synthetic oil or if you're actually being sold as a mineral oil?
Which is blended with some chemicals and sold as a synthetic oil. Basically, how do you know if you're paying for a synthetic oil or if you're paying for something which is not a synthetic oil? Looking at it, it is very difficult to test once it's gone into the engine. Also, it's very difficult for you to do. You cannot take the oil every time go and probably test it. It's expensive as well.
So how do you figure out the difference between synthetic oils and mineral oils?
Very simple test. How do you think you can do it?
Anyone who's got their cars recently serviced?
Usually service centres this is one way, they maximise their profits. They'll come and ask you. Hey, do you want synthetic oil? It's it's high performance, blah blah blah. But how do you know they actually use synthetic oils?
Probably gonna save you a couple of 1000 bucks.
Any idea?
Very easy way is to mileage, yeah, but that's after 10,000 kilometres, right? You can't wait until then and check on it. One very easy way is the GST. Earlier it used to be the VAT, the GST, which was being charged on it. I believe it is a lower GST for mineral oils and it's a higher GST for synthetic oils. VAT used to be different. I think 4% and 12% earlier.
I'm not sure about GST, how much it is, but.
They attract different, you know.
Trade.
Yourself from getting scammed the next time around. Now the last component is the oil philtre, so the reason we have the oil philtre is we circulate the oil through it so that any engine particles, any debris, metallic particles, nonmetallic particles. So they're all captured in the oil philtre. So your oil which is circulating through the engine basically remains without any damage, right.
So I think this this pretty self-explanatory pretty much on the theory side. So any questions with this?
Just a quick couple of things which we wanted to cover. Any questions with lubrication system, specifically with oils, most of it is. Anyways this theory you can just like have a look at that quickly.
There are no questions and I think we are good to start with the next one. OK, hold on.
I'm sorry about this. Just give me a second.
Oh, this got closed out.
K fuel systems.
OK, it's it's not in our scope, which is the reason why I've not exactly covered it, but if you wanted, I can probably pick up some materials and I can share it with you.
OK.
And then try to share some information with you and that is do you do you work with formal location is it?
If it is, I would like to connect with you on a on a on a rather interesting project which I'm working on.
Emissions part OK if you can just drop your contact number, I'll, I'll. I would love to get in touch with you on that, OK.
Super.
OK, so let's, let's just recap what we have seen so far, right?
What we have. OK. Yeah, I'll, I'll. I'll probably refer to that. So. So what we have looked at so far is we've looked at engines.
Right. We've looked at 4 stroke cycles. We looked at how engines operate. We looked something at the components and we were doing it mathematically, right. We were we were writing mathematical equations. We understood how they work and the primary parts were fuel plus spark, right. So this is how we started off.
Thank you. Thank you for that Danish, yeah.
So once we covered this, then we took a slight detour because we were talking about efficiencies of the engine, right. And when we spoke about the efficiencies we spoke about how a lot of heat was being lost in the engines. So which led us to covering lubrication.
And cooling systems, right? So with this, we've kind of covered the the you know the the supplementary systems which we wanted to cover with respect to the engines. Now the only thing remaining with the engines is to go back and try to figure out all the fueling system works. So Spark we don't have to exactly go much more.
Into depth over here, basically because that that that's just going to be like.
Too much of like theory on that and we don't have to do that. It's not necessarily in our scope. So we don't have to do that. But fueling systems happens to be in our scope. So next what we'll do is we'll start looking at Co link systems, OK. So I just want you to think back, I want you to remember what all we did. So what the engine basically does is it takes some amount of air, right. So this is basically what is going into the engine.
And this air is being measured.
Right. You know how to measure it? There are sensors you can kind of, you know, the mathematics behind it. Once you measure it, you kind of have a look up table which tells you what is the air fuel ratio that you need to run and then to this mixture you inject some fuel. So this fuel injection, we do it using fuel injectors. We've also seen it. So now what we are gonna do is we're gonna see.
How this delivery is happening?
Right. So we're gonna understand how this fuel, which is basically sitting in the fuel tank.
How do we deliver it into the cylinder? So this is gonna be the scope for us. That's what we're gonna be covering as a part of the fueling system. OK, so let's get on with it.
And we're gonna be looking at it both for mpfa engines as well as direct injection engines. So before we go in, we'll just do a very quick recap. So we've already seen what air fuel ratios are. So air fuel ratios is defined as the mass of fat divided by mass of fuel. Then we also have a factor called Lambda. So which is basically taking into account the stoichiometric ratio also. So this says that Lambda.
Is equal to.
A for our current AFR divided by your stock your metric add fuel ratio. So the reason we use Lambda is anytime Lambda equal to one it means you're running at stochometric ratio irrespective of whatever fuel that you are running with. So Lambda less than one is always rich Lambda greater than one is always lean. So that's what we see here. How does the engine behave with respect to different air fuel ratios?
When do you make power? When do you make fuel economy?
What is the ideal point for you to make power and fuel economies? We've seen that we've also seen that emissions are controlled by something called as TWC, which is a three-way catalytic converter. So for the TWC to work, the engine has to operate in a very narrow Lambda range, right? So somewhere between 14.2 to 14.9. So that is basically the area that we work. And this is basically where the engine emissions are lower.
If you go richer.
I can't see and CEO will become higher if you go leaner, your Knox content will become higher. So it's like a CISA, which you need to balance exactly at the centre.
Now let's look at how the fuel systems have worked over the course of time. So we started with carburetor systems, so carburetor system is a mechanical system. Then we moved into fuel injection systems to be more specific, we had port fuel injection systems and right now we are talking about something called as direct injection systems.
What is the difference? Difference is where do you inject the fuel so in port fuel injection you are injecting it into the intake port right? So this is basically where you are injecting the fuel injector is sitting here.
It is the port. It is not into the engine, which means this is. You can call it as before the inlet valve.
In a direct injection system, you are injecting it directly into the engine cylinder. This is basically gonna be after the inlet valve.
K So we'll take a quick 5 minutes or 10 minutes break 225 two 35 will restart. So when we come back we'll quickly run through what exactly the calibrator did. We're not going to go into the detail. It is not in our scope. We'll also read. We'll also discuss about port injection. We'll also discuss about direct injection. OK. So let's take a 10 minutes break 225.
235 on the clock. We'll restart.
OK, let's restart.
It OK.
Right.
So let's let's start with the very first system which is the carburetors.
The carburetor also happens to be something like.
Right.
One second.
K Just confirm if you're able to hear me.
Let me know if the Audio's OK.
OK, great. So the carburetor is a purely mechanical system, right? And in a lot of ways, it's like it's set in its ways and it's it's, it's a pretty old way of doing things. Now, the carburetor worked on a very simple principle, which is called as the ventury effect. So the ventury effect is basically something which states.
When air passes through a narrowing like this, right? When you have a converging section like this.
What happens is you have a pressure difference, right? So this pressure difference basically pulls fuel into the Airstream. So by passing add through a ventury you are sucking the fuel, you're putting it into the engine. Now the drawback with this is it is a single dimensional system. So imagine a scenario like this OK.
You are. Let's go. Going at, say, going at 20 kilometres per hour. Engine is at 1500 rpm.
Suppose you wanna go fast. OK, you're gonna go fast in the sense you want engine RPM to increase. You want the speed to increase. You wanna basically go fast.
So what do you do? You just open the throttle.
Right. So this what you do, you just open the throttle now when you open the throttle in the case of a carburetor, of course, this is the throttle valve you see here. So the throttle valve is gonna open. But just because you open the throttle, Val will not start flowing through. Why? Because this ad is being sucked in by the engine, right? So the ad is being sucked in by the engine.
And how much of an ad can be sucked? This kind of depends on the speed of the engine.
Right now, only when the speed of the engine increases, more air will be sucked in. More pressure difference will be there, more fuel can go in, more fuel goes in. Then again you produce more torque engine speed again climbs up, engine goes more faster, right? So it's it's basically a system wherein with a carburetted vehicle, especially when you're travelling.
You suddenly press the throttle, nothing will happen. Engine will not even respond, right? Trust me on it. Engine will not respond if you press the throttle suddenly engine will not respond. It will take almost 10 seconds. 15 seconds for the engine to slowly pick up speed and then you know for your for your vehicle to start moving fast. I don't know if you guys have experienced it, but if you can go drive an old Maruti 800.
The best vehicle to experience it will be the Maruti Omni, right? So usually people will tune up your engines for more fuel efficiency.
See and you take an Omni, you press the flow, you press the throttle buried to the floor. The vehicle will not climb speed. It'll it'll not at all pick up speed, right? I mean, of course. I'm I'm. I'm just talking about it from the perspective of cars, which we had available in India or basically a very normal carburetor. We also had carburetors, which were much more advanced we had.
A company called Weber Right Weber carburetors were what we started racing with.
Sometimes we took a bicarb Breakers. We took four bicarb Breakers, put it on a car, and we were running with multi cup setup individual cups at. I mean those are all possible but does not change the basic fact that the carburetor is a purely mechanical system with not much to do in terms of like you know, dynamically responding to challenges. But then came the fuel injection system with the ECU.
Where you had all sensors and the sensors can send data.
And you had control strategies, which can basically like think how the all the system has to work and you you can you could do a lot more of things with ECU based system than what was possible with carburetors for that reason. And since carburetors have not been in any production vehicle after 2000, I don't know 2004, 2005, none of the cars had got carburetors.
And I think after BS.
6.
None of the bikes have a carburetor also, right. Even if they do have a carburetor, you have something called as E cut, which is done by this company called ucal.
I was. I mean, if you know of ecubs I I was. I was there when the ECUB was being developed. So basically after BS6 right which was sometime in 2020, the last four years we've not had any carburetors at all cars, bikes or other ways. So for that reason, I don't think it's necessary for you to go spend a lot of time trying to understand how the carburetor works.
Rather, we might as well spend our time looking at fuel injection systems. OK, so now the fuel injection systems.
Are very basic outline. I think we've already done it also. So how does the fuel injection system work? You have a fuel injector which sprays the fuel. It's place it behind the inlet valve. Inlet valve is hot. It vaporises the fuel and then when air goes in it kind of mixes along with it.
Right, so this is something which we have seen, but now in this also we can bring in some complications. So when I say complication, I don't mean it in, I I I don't, I don't say that complication as a bad term. So complication is basically like.
A more interesting thing, or it's A twist in the tail or or it's an added feature, right? Just something extra for us to look. So complication is not in the negative terms when I talk about it like that. So now look at this particular picture. OK. So you have fuel here, you have air going and you know that you need to achieve a homogeneous mixture.
Now if you need to achieve a homogeneous mixture, how do you think we can do it? Do you think you can achieve homogeneous mixture if the ad is just flowing you know linearly? Or do you think it would be better if the ad was doing all of these things right? So ad is twisting AD is stumbling, AD is also liquid, right? Ad is also fluid. I'm sorry not liquid ad is also fluid which means.
Whatever liquids do add will also kind of do similar things.
You know that can swirl around, right? You've seen tornadoes. They go around in circles. So what is actually needed for us is an add, which is Airstream, which has got a chaotic flow, right. We call it as unstable flow. We call it as.
I mean, what is the right term for it? I keep, I mean it's just not coming out turbulent, right? We are looking at a turbulent flow in the air. So we don't want air to have velocity like this. We don't want air particles to travel.
In a very linear manner like that, we call it as laminar, not linear. We don't want to have a laminar flow, which is basically a smooth flow, right? We don't want to have this because then what happens is if I drop some fuel particles into the mix so the fuel particles will just go here, right? They're not going to get evenly mixed. Whereas if I have an air flow where like the air flow is not laminar, but whereas if the air flow is happening like this, right. So you have.
Add velocities where it is basically swirling around and then you have add which is tumbling around right swirls and tumbles. There are two different terms, swirl is this tumbling is.
This right, so suppose you have add which is going in like this. And now let's say you have a fuel injector and you have sprayed some fuel over here. So you understand the kind of difference it can make right. So when you design an engine we always make sure that the Airstream here is as turbulent as possible.
We need to make it turbulent only for disturbulent. It can have a proper mixing here, right? So yeah, so all that that that's all the basics. So now the big question is how do we take fuel which is sitting inside the fuel tank and how do we deliver it to the fuel injector? That is a big question, right. So we can do it by looking at the the schematic, right, so.
We can do it in two different ways, right? So the first type, we call it as the return type. We look at how it works. So you have the fuel tank, OK.
And then you have a fuel pump. So no, no big things about it. The fuel pump is gonna take fuel, it's gonna pump in through the inlet line, right. So you have a SoC philtre here which will prevent debris from the fuel tank to get into the fuel pump because once it gets into the fuel pump, it goes into the engine. It can harm the engine. So you have one philtre here and then you have one philtre here and fuel enters into the fuel injectors.
OK, that's how it happens. But if you remember a mathematical calculation, the fuel injector will always be injecting at a higher pressure.
It's not gonna do what atmospheric pressure. Why again, think of this? Only if there is high pressure at this point, right? This fuel can basically penetrate through the Airstream. Air is coming here at one atmosphere pressure, right? It's it's not coming at very high pressure. It's coming at atmospheric pressure. It's just being sucked inside. Now. Only if this is at 3:00 to 5:00 atmospheres. Right, three to five bars. Then what happens is.
It's able to kind of like penetrate through the air stream and it's able to mix and homogenous mixture and.
Whatever. Blah, blah, blah. Whatever else is happening, that's how it happens. Now how do we make it happen? Right, so now you have a pump here. Now, this pump is basically not a high pressure pump. Right? There is a low pressure pump.
And this pump is not designed to increase the pressure of the fuel. It is a constant pressure pump, right? It just delivers fuel at a constant pressure. Now when that is happening, right. And at this point, we need to have 3.5 bar and all that this pump can provide is 1.2 bar like slightly 20% above atmospheric pressure is what it can give you.
So how do we how do we basically manage it? How do we increase the pressure when we know that this pump is not going to be able to do it so very simply what we do is we.
Over size the pump. OK, so if you take a look at this architecture here, right. What is happening here, I'll just draw one single injector alone. There is a pipe. This pipe is connected to a fuel injector. OK, let's just take one of it alone. So now what's gonna happen is you're gonna have a lot of fuel which enters into the fuel rail.
OK. And whenever the fuel injector opens, some fuel will all be sprayed out and the remaining fuel because they'll always be excess of fuel here, right? So the remaining fuel will be sent back into the fuel tank. There is something called as a return line. So the excess fuel will be returned back.
OK, this is how it happens. It is designed in a way that fuel from the fuel tank goes into the fuel rail. Excess fuel comes back into the fuel tank. Now you might think why are we doing it? Because if we do not do it this way, then we might experience what is called as fuel starvation. There are some chances that we might have fuel starvation.
If we don't kind of always have an excess fuel, so we don't want that to happen. Fuel starvation is very bad for the engine. So we'll always have excess fuel, excess fuel as always returned back.
No, rather cleverly. What we can do is on the return line we can put a pressure valve, right? So this pressure valve, what will happen is it will have a spring which is rated at 3.5 bars. So this pressure valve will open only when 3.5 bar or higher pressure is reached. So what's gonna happen is the fuel pump.
Will continue pushing fuel into the fuel drain. The return line will not open the moment fuel.
Pressure rises above 3.5 bar, the fuel pressure regulator opens up. Excess fuel will go back into the fuel tank, right? So by doing this by having a fuel pressure regulator and by having this type of a setup, we can maintain a high pressure inside the fuel system. OK, so this is basically how fuel goes from the fuel tank into your engine. There is the whole architecture. So the important components let me reiterate there is a fuel pump. There is a fuel philtre.
There is a fuel injectors per SE. Then there is the fuel drain. There is the fuel rail, right? And you have a fuel pressure regulator. So once the regulator opens, this will go back. OK? This is basically the architecture that we have now. Very important question for you. OK. So this type of a system we normally see it in.
Cars, we do not see it in bikes.
I want you to explain why is it that we do not see this in bikes.
Why do you think you cannot see this type of a fuel system in bikes?
Take a take a guess. Why is it that we see the normal, the fuel systems, whatever you see here, why is it that we do not see it in bikes? Size of the system? No, not not. Not exactly.
Have two port injection. This has got four port injection so it can be used. It's not about that cost. OK fuel tank is above correct. You got it right? Right. So observe how the fuel is going back into the fuel tank. Right. Observe the return light. So this is something which flows by gravity, right? So in cars.
Usually what happens is your engine is at a higher level. Your fuel tank is mounted underneath the rear floor, which means it's at a lower level. So in cars this can go back due to gravity. But in bikes, where exactly is your? Is your fuel tank present right?
This architecture does not speak about it, but actually in bikes the fuel tank will be sitting up, the fuel injectors will be sitting below it, which means you cannot have a return type fuel system in a bike. You will have to go for a return less fuel injection, right? So how does a return less work? Very simple. You take this fuel pressure regulator, you move it into the fuel tank.
So instead of pressurising only this area.
What you do is with a bike you pressurise this entire area right so fuel pressure regulator sits inside the fuel tank the fuel bypass happens inside the fuel tank there is no return fuel just goes here it's maintained at 3:00 0.5 bar pressure so excess fuel no excess fuel excess fuel will just go out from here so imagine that instead of having a fuel drain alone where the pressure is being built?
You now have the whole system where it is built and the return is just moving into the fuel tank right.
So that just the difference between return and return list type. So you have two types of fuel architecture. One is a return type, one is a return list type return type, the fuel pressure regulator sits on top of the engine return list type. It sits inside the engine right?
Let me just see if I can show you some pictures.
I have been unfortunately wanting to do it for a lot of long time but.
As you can see, there's too much of work to be done with it, so I've not.
Exactly got into.
Arranging it right so now this is a fuel pressure. I mean the fuel system in St right. So can you see my mouse here? It's moving on the top right. So this is the fuel pressure regulator, right? The red ones are the fuel injectors, the four injectors and the metal component that is your fuel drain. OK, so.
It will have inlet on one side, which is probably going to be this side. This is this is where the inlet is. Of course it comes out here.
Return is gonna be club top here. OK, so this is how the actual fuel injectors plus your fuel pressure regulator. If you're wondering how big it is, how does it look? This is how it is. OK. I'll quickly check if I have any more pictures of it.
Yeah. So does this the inlet line, which you can clearly see, Yep, that's about it. So this is the inlet, this is the exit, right? So this is the fuel system I don't have.
Yeah. So I don't, I don't have it for any other system.
Yep, that's about it, right. So lubrication. Did we see oil sump? I think that this we did see last time around, right? I did show you.
It is the oil sync and all. Yeah, we did see it, right. So let me get back here. So why are we not storing excess fuel in the fuel drain for next? No, we will be storing excess fuel. So the fuel rail will contain sufficient fuel for at least 10 or 20 cycles.
Right, you will have sufficient fuel in it, but the point is the fuel rail is holding pressurised fuel, right. It holds it because the size that you see here. So this size will hold sufficient for at least 10 to 15 cycles. It will store sufficient fuel not just for one, it will hold for 10 to 15 cycles.
But we don't want to have too much of A capacity here because we have too much of A capacity. Then you are going to run the fuel pump for a longer time. So ideally it is like a balance between the size and cost and what exactly it is that you need.
OK.
Right. So yeah, now let's go and let's look at the fuel pump. So the fuel pump is a very simple motor impeller arrangement, right. So you have motor here and you have an impeller. So all it's gonna do is just work like a regular centrifugal pump. It just gonna suck fuel and it's gonna send it out. But.
There is a very interesting thing which happens with the fuel pumps, right?
So I might be wrong. My mathematics might be a little wrong, but I think apart from your your engine right apart from your engine and maybe a couple of other components which are mostly mechanical components, the fuel pump is the only other system in a vehicle which is running whenever your engine is also running and this fuel pump happens to be a motor.
Right. It's a motor which is running. Now let's do a very simple calculation. Suppose you have a car that is done 1,00,000 kilometres, right?
Suppose you have a card that is done one last kilometre. Just just a very quick thing to appreciate the kind of engineering which goes into it. Now assume that we are driving it inside the city, right? So inside Chennai city, my average speed was always 18 kilometres per hour.
I I I I used to notice it every time I go for filling up fuel. I had a Altis. So where every time I reset the fuel I'll have to cycle through the average speed and all of those things. So.
It was around 18 kilometres per hour, was the average speed. Now assuming that 12123? Yeah, assuming that I've done one Lac kilometres at 20 kilometres per hour. This basically means that my car has run for 5000 hours, right? 1,00,000 kilometres is equal to 5000 hours. Now of course this is not taking into consideration.
And all those time the vehicle was idling so just to be on the safer side let me multiply it by 1.3 right I'm just increasing it by 30% to take into account all of those times that my vehicle was spent idling so 6500 hours is basically the time that my fuel pump has run.
6500 hours it has run and it has kind of not.
It is kind of not broken down or or anything like that, is it right?
20 in one hour, if you do 20 kilometres, 1,00,000 kilometres would basically take.
6005 thousand hours. I mean, I don't know if the math is right, if I'm doing something wrong 5000 hours into 20 kilometres. Yeah, I mean, it's average. So anyways, it'll be OK, right? So not everything would have been done at 20 kilometres, some would be slower, some would be higher. It just average. So this is kind of like equivalent to almost about 18 man years, right? 18 years.
Of course, it's not going to be 18 because I might have done something at 80 kilometres, 100 kilometres on the highway. It would have been different, but on an average out, this is kind of the life that I've got.
So now can you tell me how in the world do I take a normal motor and I I build it so that it's it's kind of got this kind of a life. OK, let's not take 6000 Finder. Let's take 50% of it. Let's take 3000 hours. How do you build a motor which is so small, right? It's so small. How do you build a motor?
That it's able to run for 3000 hours without failure, right?
So the the physics seems to be really awesome, right? So one of the reason how they're able to extract so much of life out of this motor is basically by designing a cooling system for the motor. So can you tell me what is the cooling system that has been designed for this motor? How do they manage to reduce heat? How do they manage to reduce friction because you reduce all that then automatically?
You're going to have higher life, right? So how do they manage to do it with this fuel pump?
Looking at this, how do you think they basically manage to build a motor which can run for 3000 hours, right? Very simple reason. They do that by taking this fuel pump and they're not running it outside. They basically dip it into the fuel, right? So your entire fuel tank, the fuel which is present, that becomes a cooling medium for your fuel pump, right, so.
Go back and look at it here. Your fuel pump is always submerged in fuel so which means you have the best possible cooling possible for your pump because you know that the thermal capacity of fuel is extremely high.
It has a very good cooling properties, so you take a motor, you completely immerse it inside the fuel. That's the best scenario for it to operate. It is always submerged. It is always cooled. It is it is, it is much more better for the fuel pump to run in that way, which is also the reason why you should try to keep your car with at least half a tank of fuel. You drop below half a tank, then you are exposing the fuel pump.
And the fuel pump not getting sufficient fuel for cooling.
These are always gonna be like some things which reduces your.
You know your your fuel pumps life, right? So the reason why it's kept submerged in the fuel tank is basically for that, right.
So next comes your fuel injector. So the fuel injector is a very basic solenoid valve. So whenever you supply a 12 Volt pulse width modulated signal then it's gonna open up and it's it's gonna basically spray. Is it true for bikes? Yes. I mean, if you have a fuel injected bike if you can have more than half a tank of fuel it's always good. Right. So having more than half a tank of fuel is good in two different ways. One if you have more than half a tank fuel sloshing will not happen.
So what is sloshing?
Suppose you have a fuel pump like this right. Now suppose you go and you take a a very sharp turn, right? Suppose that you only had so much of fuel, maybe 1/4 tank of fuel. So when you take a really sharp turn, it is very much possible that the liquid level goes up like this, right? Fuel will slosh. So when fuel sloshes, your fuel pump is running without any access to fuel. So it leads to fuel starvation.
Fuel starvation can accelerate pump wear and debt because your.
Colour your whole pump. It is designed to pump fluids. It's not designed to pump air right. If you run it without fuel, if you're subjecting it to starvation fuel pump life will reduce. But trust me, if you experience fuel starvation then pump life is the least of your worries. If you experience fuel starvation, then you're going to run your engine extremely lean. Running an engine extremely lean.
Will 100% you know surety it will damage your engine, right? So once the engine is gone, what is the fuel pump? It's basically like a small component right? So.
The reason why you should never do that, but that's not exactly a problem with modern cast fuel sloshing, because in modern cars what they do is they put some baffles inside the fuel tank, right? There'll be some baffles, so these baffles will prevent your fuel from sloshing. And again, the fuel pump is also encased, right. Fuel pump is also encased.
Yeah, it's encased in a casing to prevent fuel starvation, right? So not exactly relevant in modern days, but still it's a good practise because apart from this starvation, it also prevents the fuel tank from getting rested and fuel tank resting is a very real problem, right? So.
What exactly does the fuel injector do? Fuel injector is used for metering the fuel you inject the amount of fuel that you need, you can metre it exactly and I think we've also worked on duty cycles, right? Please let me know if you have. If you have done this. We have also worked on the duty cycle during the mathematical equations. Yeah. So is it possible to accurately metre the fuel? Answer is a big yes so.
How accurate can we metre it? I think it's possible for us to go down to.
As much as first or second digit decimals in in in fuel quality, right? I mean it's it's possible for us to do that. So the minimum time for fuel to open close it's it's it's extremely like small and you would be able to achieve that kind of accuracies. Now the fuel injectors when we when we take them as a system.
There are various types of fuel injectors. There are various configurations in which this fuel injection is available.
Of course, one of it is the size of the fuel injector. We've already seen three 3500 and you know why you need to use it. So all of those things, that's one of it. But apart from it.
This also comes in different configurations based on the spray patterns and control type. We'll first look at spray patterns, which is a pretty easy way to do. Then we'll go into the control type. So spray pattern as the name suggest, OK, this is capacity right, so capacity is you we we've basically done this.
Let me probably skip this. Go to the spray pattern and come back here. Right. Let me come back here. So since I I started with this spray pattern. So now spray pattern. This depends on the way the holes on the injector is arranged. Now spray patterns can be differences in terms of cone angle. Right. So cone angle is this right? You could have narrow cone angle. You could have white cone angle.
You could have offset cone angles. You could have split cones, so why do you need to have all this? You need to have all this depending on the position of your injector. Now you'll have to remember.
Not all engines are manufactured from the scratch to be a fuel injected engine. A lot of engines were basically converted from carbureted engines. So which meant the placement of the injector per say is far from being ideal, right? So now in one case you might have a fuel injector which is present here and the valves are let's say present here.
So now you might want to spray the fuel like this. Another case the fuel injector might be present here, right? And fuel injector might be here.
Now in this case you want a wider cone angle, right? Sometimes you don't want to spray it on one side, right? Maybe you just want to maintain a fuel injection pattern like this, right? If suppose, this is all your injectors are located. So depending on where your fuel injector is placed, we will have the need for different types of fuel spray patterns. We can also have need for the whole diameter, right?
Suppose you need to have a very fine mist. You'll go for very fine holds number of holes. So all of these things you can you can basically like you know, changed based on your CFT simulations and things like that. Is there a rule of thumb? No, nothing like it. It is a design process and all you need to know is understand that there are different types of patterns available and whatever is the best for the application, you do that.
OK. But the more important thing is basically how you control the fuel injector.
Right. Let me let me just probably like you know, give a very small introduction and then I'll get into the theory there.
How do we control a fuel injector? Can someone tell me how do we control a fuel injector?
How do we control a fuel injector using the ECU?
How was this control happening?
So you have a PWM pulse, right?
The physical signal happens to be a PWM pulse, so if I were to plot it like this.
Right, this is going to be voltages, right?
Let's also talk in terms of current, right. So your PWM will basically be something like this.
Right, this is how you you expect the PWM signal to be.
Now you need to understand a PWM signal is being generated by a microcontroller, so microcontroller can in real time raise up into five volts and then drop it. It can basically work really really fast, because these are transistors which are used right? So what is the response time of a transistor? I would say this works on nanoseconds.
Right, it's it's it's extremely quick. It is working on nanosecond levels because all it does is it just sends a signal, right? It just a transistor. It can work really fast. But right the big but is what exactly is a fuel injector? The fuel injector is not a transistor. The fuel injector is a solenoid. It's an electromagnetic device, right?
So the fuel injector when you supply this PWM to it.
Let's say the fuel injector is closed, right? You see this line here? Fuel injector is closed now. The moment a pulse width goes, it does not immediately open up, right? A fuel injector will always have a ramp up time like this. OK, so this is basically how your fuel injector will open.
It'll take a definite amount of time to open up because it happens to be a mechanical system. This is a electromagnet, so which means an electromagnet has to get energised. Current has to flow and then the magnet starts working and then the plunger is pulled back. So it's going to work something like this and then it's going to have an open time, OK and when the fuel injector signal is cut out.
Cutting out will be faster, but still takes time, so the fuel injector will basically close like this.
But I mean, I'm just drawing squiggly lines for you to see, but what I'm trying to tell you is that there is always a delay in opening and there is also a delay in closing, which means your injector is not exactly gonna follow a square pulse. It's gonna be a trapezoidal kind of a thing. It's gonna have some delays. So this delay, we call it as dead time.
So do you think it matters? Yes, it does. Right. So now you say, hey, send five millisecond worth of fuel, right? This is all your issue calculates and says, but this might actually correspond to 4.5 milliseconds of fuel. There is some dead time here. There is a little kind of a dead time here, but there's gonna be only 4.5 milliseconds. So there is a dead time.
Where the fuel injector is not switching on, it's not operating. There is always going to be a dead time. So how does the ECU work with it? So if you get into the control strategy of the ECU, the ECU will have a calibration parameter which talks about dead time and this dead time is a function of voltage battery voltage, right? So what we'll do is we'll plot that time.
With voltage and it would probably look something like this. So the lower the voltage higher the dead time.
Higher the voltage it kind of remains constant, right? So we will give a 1D lookup table to the ACU and we'll say, hey, anytime the calculation is five milliseconds, battery voltage is, let's say 3 point 13.5 Volt. So add let's say .6 milliseconds to it. So this will say .6. So the issue will not add five milliseconds but it will add 5 + .6 milliseconds. So then what happens is if you had at that time of.
You know something like this, then ultimately you will end up injecting 5.1 milliseconds worth of UN, right? So this is called as injected dead time. This is an actual impressive problem. It is not because of any design things. It exists because there's a physical system. OK, so now that's what we're going to see. So what happens is what is the pulse width? How does it look like?
And how does the injector open?
So injector does not open the same as the pulse width. Injector is open only for a lesser amount of time because this time happens because your fuel injector, your current needs to rise up right? So your current flows into it. It starts energising and once the current is completely energised right current flows happen and completely energised. Then your fuel injector starts working. So this shaded portion here.
This is your dead. OK that I was talking about. So now this dead time can become a problem. Once you go for larger injectors. So which is why you don't go for one big injector. Most of the applications where you need to have a big injector you will go for multiple small injectors, not multiple. Two small injectors 1 to work in low rpm. One to work in high rpm. You will find it on sports bikes like the CBR954R ones. So you.
Of injector on the throttle body, one set of injectors on the add box. So the ad which is coming into the engine will already be premixed with some fuel so that your main fuel injectors need not inject so much of add fuel into it. OK, don't worry about calculating how much air and things like that, it runs in closed loop so that takes care of the the secondary injections right now. Is there a way for us to avoid this from happening? Yes you can. So what we do is.
There are two types of injectors which we can go, so one is called as.
Peak and hold injectors. I mean the regular injectors which is also called as saturated injectors or high impedance injector. And then we have the low impedance injectors so the high impedance injector is a normal injector where if you take the two pins you measure the resistance between them. You will see something like about 30 ohms right?
Simulator.
Or electrode. So we we've already seen it before, so I'll just show you the injector impedance. I mean impedance is resistance right? So injector resistance we can quickly check it out here.
So this is the fuel injector, right? I would remove the coupler taken a multimeter.
And let me measure the resistance.
OK, so this is resistance.
OK, car is not switched on so.
Logically, it should work even without the car switched on, but that's not built into it, so let me switch it on.
What happened?
I think it's a problem with. OK, I'm sorry. I'm testing it on the coupler. Right. There's a coupler. This is the injector. I'm testing it at the wrong place so I have to test it here.
So you see 16 homes of resistance, right? I hope you're able to see it. So this basically tells me that this is in 2K thousand, so multiplied by thousand you will get 16. But this tells me that this is a high impedance injector, right?
Annoying beeping in my ears, but there's a high impedance injectors which usually has 35 ohms. They're showing that 16 ohms 16 is still fine. So there's a high impedance injector, which is what normal injectors are. So how it works is.
It just flows the same amount of current and then it switches off right. The current does not vary.
But the problem with impotence or the resistance is that this resistance causes I square at losses. So when you have about 1 amp of current flowing right and you have 35 ohms right 1 ^2 is 1. So you have around 35 watts of heat which will be produced, right? So that happens here. But then you also have something called as low impedance injectors. I'll explain about that. So in low impedance injector initially there is 2 ams of current but after that it drops to .5 amps so.
15 square 25 zero .25 multiplied by the resistance is as low as 5 ohms or something like that. So this kind of gives you 1.25 watts. So the amount of heat which is lost in low impedance injector is much less high impedance. Injector is high but more importantly apart from it, what happens with high impedance injector is that since you are passing a lot of current.
The injector gets energised quicker, which means it opens up faster also. So let me reiterate it. There are two types of injectors. One is high impedance or saturated injector.
The other one is low impedance or peak and hold injectors, so peak and hold injectors. What happens is you pass a lot of current in the sense 2 amps and once the injector is completely opened or once you detect the two amps of current as flown, you drop the current to .5 M .5 amps. You don't need 1 amp or two amps to kind of keep it open so to keep it open you need lesser amount of current.
Advantage is when lesser current flows through it, we kind of like have lesser I square ad losses, right?
So this is basically how the peak and hold works. OK, so we've seen this.
Right. So now when it comes to port fuel injection system, we'll have to target our injector spray directly behind the inlet valve. If we do not spray it on the inlet valve, if it hits the walls and things we have wall wetting which occurs. We've already discussed it. So that is basically the problem which happens with your.
Your, your, your portfuel injection system. Now this valve wetting and the valve wetting and cylinder wetting and and and piston wetting. So all of these will cause an increase in hydrocarbon emissions. So now as we move towards a point where hydrocarbon emissions are also very strictly controlled, we also need to go in for lesser CO2 emissions. We've kind of adapted. We've kind of developed technologies.
Which takes the fuel injector from the port and it kind of moves it into your directly into your cylinder.
Right. We've seen this earlier. So we directly move the fuel into the engines into the cylinder. So these type of systems, we call them as direct injection systems. So normally direct injection systems, you see it only in diesel engines, but these days petrol engines have also started having that. But when it comes to direct injection system, one thing you'll have to take into account is you cannot inject fuel at 3 bar or five bar.
Why? Because inside the combustion chamber, the piston is gonna like generate pressures of about easily about 150 psi, 202 fifty psi of pressure will be generated. Now if you want to inject fuel into that high pressure environment, you will need to inject it at much higher pressure. So usually the fuel pressure it varies between 40 to 350 bars.
And we kind of like presentation second generation multiple generation of systems are there. So where one generation we have non variable fuel pressure and then the current generation, the modern generations we have variable fuel pressures also.
But the most important thing with direct fuel injection system is that we can run it in something called S stratified fuel injection mode, right? So if you remember.
How we define petrol engines right those are few from mechanical engine background whenever someone asks what is the difference between petrol and diesel engines one of the very first things that we say or we've learned to say is that petrol engines are homogeneous engines?
Right So what is homogeneous engine mean homogeneous engine means whatever is going into the engine is air and fuel mixture both of it in gaseous state both of it is equally mixed and you cannot tell one from the other that's what homogeneous mixture is but in gasoline direct injection systems we can also run it in something called as stratified injection mode.
Right so stratified injection mode is something where.
You run it in non homogeneous mixture. Now we've been told that.
Petrol engines cannot run non homogeneous they have to run that is basically a problem when you're doing port injection but when you're going for direct injection you can actually get away with it so how do you get away with it is whenever you want to do stratified injection what you do is.
You spray your fuel like this right you spray the fuel into the combustion chamber and you kind of localise the fuel only in this area right and then you have your spark plug which is present here So what happens is in a stratified injection you are not mixing the fuel equally all around but you are spraying the fuel directly next to the.
Let me just check.
This there OK I think it's still there it's little but what you do is you directly spray it into the immediate vicinity of the spark plug and you just ignite it right so which means you can run your system in extremely lean conditions.
Normal engines cannot run lean. They'll start misfiring, but with gasoline direct injection systems alone you can run it in extremely lean conditions and still get away with it, right?
So how we do it? I think there is. There is still quite a quite a bit of things to do it, so we will, we will probably like handle that in the next session, right.
So I think we can stop it with this here. So this would be a logical progression for the next. I think I have gdas and I have diesels also. So that would take one more session. So yeah, we can probably stop it with it here. So any questions with this?
Do you have any questions?
OK, I have yet another query. There was one class which I had to. I mean I had to cancel, right? So last week's. So I wanted to ask if we can have that class sometime during the weekday. So this coming week, can we have that one extra session sometime during the weekday we can do it between 7:00 to 9:00?
Or eight to 10, whichever is OK with you. I'll anyways post it in the group also. So I want you to decide and probably tell me which day and what time. And we can either officially schedule it or if not officially I'll try to unofficially schedule it and I'll try to fix it up. Right.
We'll we'll post it in the group also, yeah. So something.
Tomorrow morning.
A little difficult because.
I don't know if you can see it, but I'm I'm sitting in Continental today, right? So I'm here in Bangalore and I'll be travelling back tomorrow in the morning. So tomorrow morning might not be possible.
But we can probably like next week or something if I'm back home, I can schedule it on Sunday mornings. So usually Mondays, Tuesdays might be busy. Wednesday, Thursday, 8:00 to 10:00 I think might be suitable for everyone. Or Sunday is also an option if you don't have classes, so I'll post it on the WhatsApp group we can have.
We can. We can have a, you know, a discussion there and we can probably find Lacey. So Continental is a face to face programme. So we have an M tech, automotive, engineering or electronics electronics running for continental. So I'm here for the face to face session. I'm here at the the Bangalore office.
OK, I end of mistote on it, but I'm here in electronic city.
Are you here in the office now? I have time until 4:10 for the next class.
If you're here we can meet up I am not sure which classroom it is but we can probably let me know if you're here in the office right?
Support right so let me stop the recording and.

SAJEETH KUMAR . stopped transcription