session 6 - fuel and combustion

pre-ignition

fuel air mixture ignites before timed spark because of a contact with a hot surface

detonation

happens after timed spark. remaining mixture spontaneously explodes due to excessive heat/pressure creating a shockwave.

octane rating

a measure of gasolines ability to resist knocking or premature detonation

cetane rating

a measure of the ignition quality of diesel fuel

flash point

the lowest temperature at which vapours of that liquid will ignite if given an ignition source

flash point of petrol

-43 degrees

fire point

lowest temperature at which the vapour of that fuel will continue to burn at least 5 seconds after ignition

volatility

ability of a liquid to change to a vapour

2 way catalytic converter work? (diesel)

converts carbon monoxide into carbon dioxide

converts unburnt hydrocarbons into carbon dioxide and water

3 way catalytic converter work? (petrol)

converts nitrogen oxides into nitrogen

converts carbon monoxide into carbon dioxide

converts hydrocarbons into carbon dioxide and water

4 main pollutants of a diesel engine?

• carbon monoxide

• hydrocarbons 

• particulate matter

• nitrogen oxides