Fraction of Fuel burnt

[Raghav_Jagan]

Hey guys.. i looked up in the net, but i couldn't get a tangible answer..
Approximately.. What fraction of Fuel gets Burnt during the combustion process in petrol and diesel engines.??
Can anyone help me out?

[shorod]

Are you asking what percentage of the air/fuel mixture is fuel, or are you asking what percentage of the fuel in the air fuel mixture burns versus how much is wasted? You'll need to also specify if you are concerned with an old, carbureted engine or one of today's "efficient" computer controlled DI engines.

-Rod

[Raghav_Jagan]

i am asking about a old fashioned carbureted engine..
My question was, if i send 150cc of air -fuel mixture into the cylinder.. How much of them is burnt.. how many cc's of air-fuel mixture remains wasted?.. i am not talking about the all of the exhaust gases.. specifically, about the hydrocarbons,that represents the un-burnt fuel..

[Ginsengbull]

It would vary considerably, depending on if your air fuel mixture were at ideal conditions. Only way to tell for sure then would be to analyze the exhaust gasses, and the co2 content will indicate your combustion efficiency, provided the exhaust isn't being diluted by an air injection system like they had on 1980's AMC products.

[Raghav_Jagan]

Yea.. lets assume,. My AF ratio is 16:1..
i am just assuming a lean mixture.. at a moderate speed..

[maxwedge]

Again no way to tell what the exhaust stream contains without an analyzer in the stream, there are too many variables engine to engine to support any accurate estimate.