Sources of Power to the Farm - Heat Engine

Engines are mechanical devices that convert heat energy of fuels into mechanical energy.

Heat engine

The fuel is ignited and burned outside a cylinder and the heat energy is applied indirectly to a piston by an intermediate medium, usually water vapor.

External Combustion Engines (ECE)

A_______is an external combustion engine.

steam engine

The fuel is ignited and burned inside a cylinder and the resulting explosion causes an instantaneous application of pressure to a piston.

Internal Combustion Engines (ICE)

_________have completely replaced the steam engine for all types of agricultural power applications.

Internal combustion engines

Most farm works are accomplished by machines powered by the_______

Internal Combustion Engine (ICE).

___________has completely replaced the steam engine (or External Combustion Engine) for all types of farm power applications.

Internal Combustion Engine (ICE).

The fuel or combustible fuel mixture is placed inside the cylinder in a_________and compressed before it is ignited. gaseous condition

gaseous condition

Since the is ignited and burned inside, the gas engine and all engines that operate in similar manner are called ICE.

fuel

Confines the expanding gasses and forms the combustion chamber.

cylinder block

The term "____" is often used synonymously with cylinder blocks.

engine block

Houses the valves and forms a cover to the cylinder.

cylinder head

Contains the______in SI engines and the fuel injectors in Cl engines and some SI engines

spark plugs

Between the head and the block, a______seals the combustion chambers, and water and oil passages.

cylinder head gasket

serves as a sealant between the engine block and head where they bolt together.

cylinder head gasket

The______of an engine constitutes the basic and supporting portion of the engine power unit.

cylinder

Its major function is to provide space in which the piston can operate to draw in the fuel mixture or air (depending upon spark ignition or compression ignition), compress it, allow it to expand and thus generate power.

cylinder

receives and transmits the pressure forces in the combustion chamber to the rotating crankshaft

Piston Assembly - Piston

The top of the piston is called the_____and the sides are called the skirt.

crown

The face on the crown makes up one wall of the combustion chamber and may be a_____or highly contoured surface.

flat

The piston is closed at one end and open on the other end to permit______attachment of the connecting rod and its free action.

direct

reduce cylinder wall contact thereby reducing friction losses and wear

Retain compression

Rings traditionally have been divided into three types, according to function.

Piston rings

Counting from the top of the piston, the first and second rings are______, whose task is to control blowby.

compression rings

The middle ring is the_______, which keeps excess oil from the combustion space.

scraper

The last ring is the______, which is serrated to deliver oil to the bore.

oil ring

The connecting rod is connected to the piston through the_______.

piston pin

serves to fasten the piston to the upper end of the connecting rod.

wrist pin

It connects the piston to the crankshaft and transmits the power of combustion from the piston to the crankshaft

connecting rod

The end connecting the piston is known as the______and the other end is known as the _______.

and the other end is known as the . small end ; big end

converts the rectilinear motion of the piston into rotation

crankshaft

The offset from the axis of rotation is sometimes called___________

crank throw or crank radius.

Has a harmonic balancer, or vibration dampener, mounted on the front where it muffles___________.

torsional vibration

keep the engine at uniform speed when the crankshaft is not receiving power from the piston and store energy that keeps the engine rotating between power strokes and smooths out engine operation.

Flywheel

The_______consists of the valves, camshaft, and other associated parts.

valve train

The valves control the flow of the incoming________and the outgoing exhaust gasses.

air-fuel mixture

The_______are larger than the exhaust valves, and many engines today have two intake and two exhaust valves per cylinder to improve efficiency and performance.

intake valves

The valves are operated by the action of the______, which has separate cams for the inlet, and exhaust valves and iIt rotates at half the speed of the crankshaft.

camshaft

The cam_______the valve against the pressure of the spring and as soon as it changes position the spring closes the valve.

lifts

The cam gets driven through either the______and chain system from the crankshaft.

gear or sprocket

It is connected by chain, gears or a belt to the crankshaft at one end and the camshaft on the other.

timing gear

It is marked with_____all around its perimeter.

tiny increments

The_____correspond to degrees of timing from the straight-up timing position of the camshaft and crankshaft.

marks

named after Dr. N.A. Otto, a German, who patented the first successful engine operating on four-stroke cycle principle.

Electric (spark) ignition engine

an Englishman, patented the first two-stroke-cycle engine.

Dugald Clerk

The electric ignition engine utilizes an_____produced by a spark plug located inside the combustion chamber to ignite the compressed air and fuel mixture.

electric spark

Fuel used is gasoline, and metering is done by a device called a_____.

carburetor

other term for Electric (spark) ignition engine

OTTO CYCLE ENGINE

This engine utilizes the heat of compressed air to ignite the fuel as it is being injected inside the combustion chamber. Fuel used is diesel and metering is accomplished by the fuel injection system

Compression (injection) ignition engine

other term for compression (injection) ignition engine

Diesel-cycle

A German engineer patented the first engine designed to operate utilizing the heat produced by high compression for igniting the fuel charge in the cylinder.

Dr. Rudolph Diesel

completes the cycle in 1 revolution of the crankshaft or two piston strokes.

Two-stroke cycle engine

completes the cycle in 2 revolutions of the crankshaft or four piston strokes.

Four stroke cycle engine

Comparison of diesel and gasoline engine

Comparison of diesel and gasoline engine

The events that occur in a 4SCE are:

Intake, Compression, Power and Exhaust

These events (except ignition) occur over one stroke of the piston or _____of the crankshaft.

½ revolution

_______requires 4 strokes of the piston or 2 revolutions of the crankshaft.

One cycle

Four stroke cycle engine

Four stroke cycle engine

_______engine is one in which two strokes of the piston are required to complete the necessary series of events required to produce one power stroke.

two-stroke-cycle

The stroke compressed air in the cylinder to ignite the______.

fuel oil

The other stroke is produced by the burning gases.

power stroke.

comparison of 4 stroke cycle and 2 stroke cycle engine

comparison of 4 stroke cycle and 2 stroke cycle engine

uses gasoline as fuel, represented by octane (C8H8). Octane Rating

Gasoline engine

uses diesel fuel, represented by cetane (C16H34). Cetane Rating, Paraffin hydrocarbons or alkanes.

Diesel engine

It is also known as a water cooled engine. Water serves as the coolant or the cooling medium which circulates in the water jackets to absorb the heat from the engine.

Indirect cooling system

It is also known as an air-cooled engine. Air is directly used as a cooling agent. Instead of water jackets, there are metal fins or shrouds that are placed around the cylinders.

Direct cooling system

Small engines,________or engines used in motorcycles and even small cars have one, two or three cylinders.

stationary engines

usually have two, four or six cylinders.

Automotive engines

have more than 8 cylinders. In general, engines may either be single or multi-cylinder engines.

Marine engines

It has cylinders arranged vertically one after the other in the cylinder block.

Vertical or In-line engine

It has cylinder arranged horizontally,

Horizontal engine

It has a cylinder arranged in two rows or banks. The block resembles the shape of "letter V".

V-engine

It has all the intake and exhaust valves placed or installed or mounted in the cylinder head. These valves are operated by rocker arms actuated directly by the camshaft and from the crankshaft.

I-head engine

It has all the intake and exhaust valves located on one side of the cylinder block. The valves are directly operated by tappets or cam followers.

L-head engine

Low speed engine

below 350 rpm

Medium Speed engine

350 to 1000 rpm

High Speed engine

over 1,000 rpm

injects the fuel directly into the combustion chamber.

Direct Injection

injects the fuel in the pre-combustion chamber and accurately time the beginning and ending of the fuel injection

Indirect injection

Meter correct amount of fuel as demanded by the_______

engine load

Inject fuel in combustion chamber against high pressure

Indirect injection

Atomize fuel and assist in mixing with air, Carburetor (SI) and Fuel injector (CI)

Indirect injection

The main difference between the turbocharger and the supercharger lies in the______.

power supply

turbocharger uses the_______for its energy. The exhaust will run through a turbine that will itself spin the compressor

exhaust stream

Turbochargers and superchargers are known as______. It means that either will compress the air flowing into the engine, which provides more power to the car.

forced induction systems

This creates a considerable amount of boost, which can be as much as more power into the engine.

50%

A_______is designed to improve the power output of an engine beyond its normal operating capacity. A normally aspirated engine uses a mixture of air and fuel that is pulled into it from vacuum created by the cylinders.

turbo charger

It increases the amount of air injected into the engine, which also allows more fuel to be injected and increases higher power______.

30%

______function is the same with turbo chargers except that they are engine driven rather than exhaust-gas driven.

Supercharger

The source of the power for the supercharger is in a belt connected _____to the engine. A supercharger will compress air of the atmospheric pressure, and create the boost by forcing air into the engine.

directly

it is used in spark ignition (gasoline engines) since the power from exhaust gases is low as a result of low compression ratio.

Super charger

Reduce friction and wear by separating rubbing parts. Assist in cooling the engine by absorbing heat from parts and act as seal between the piston and cylinder wall

lubrication system

Assist in cleaning the engine

1. Oil pump

2. Oil filter

3. Oil lines

4. Sump tank

thin free-flowing SAE 30 or 40, oil for engine internal parts

Crankcase oil

heavier and viscosity, oil for transmission gears

Transmission oil

slow, non-flowing lubricant used in wheel bearing

Grease

mechanical device that controls the flow and supply of fuel mixture to the cylinder with respect to the desired speed, power output and existing operating conditions of the engine.

governor system

controls speed by reducing fuel delivery to the engine when the speed is too high and by increasing fuel delivery when speed is too low.

governor system

maintain a constant speed under different load and protect the engine and equipment against high speeds when the load is reduced or removed

governor system

Receive, exert and transmit motive forces

power transmission systems