Thread: EXHAUST EMISSIONS

Bit bored are we

Originally Posted by KENO1947

First post so please bear with me. I can not figure out where you get the CO2 figures for exhaust gas. i.e. Nissan Micra 1.2 lt produces 138g CO2/km using 5.9lt/100 of fuel. Taking fuel @ 1kg per lt (approx) over 100km 13.8kg of CO2 is produced from 5.9lt of fuel!
As CO2 is only 15% of exhaust emissions, total emissions would seem to be 92kg per 100km!!!!!!!!!!!
The only input for combustion is fuel, air and igintion source and as the laws of physics state states all mass is constant to have 92kg of emissions you would need to use 78.2kg of air, unless I have gone wrong somewhere. I would start worrying about running out of air rather than CO2 emissions.
Someone please correct me if I am wrong

Jeff

Assuming a specific gravity of 0.7 of 5.9lt equals 4.13kg fuel, mostly by weight of carbon, lets guess C8H18 is a typical fuel (iso-octane), atomic weight of C is 12, hydrogen 1, that's 8x12 of weight of C for every 18x1 of H, equals 84% carbon by weight or just under 3.5kg of carbon. Add to that twice as many atoms of oxygen (CO2 remember) at atomic weight of 16 that's 7 x 16/12 equals 9.25kg of oxygen burnt. So by that roughie calc you get 12.7kg of CO2 per 100km. Not far out for a bunch of assumptions. And as oxygen is about 20% by weight of air you would need to pump 73kg of air to do that. Then there's the oxygen for burning the hydrogen:

As CO2 is only 15% of exhaust emissions, total emissions would seem to be 92kg per 100km!!!!!!!!!!!

Nitrogen (80% of the air) passes through unchanged (mainly) some of the oxygen and water vapour is created from the hydrogen part of the fuel.

Thanks Tombie. Bored, yes, Cold, wet and miserable. So not much else to do. Might start on carbon tax next