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Originally Posted by Rick & Connie
...Now I come to the point where most people were misunderstanding me before. The primary reason for automobiles having catalytic converters and air injection systems into the exhaust is to burn the roughly 70% unburned hydrocarbons leaving the cylinders. Once past the converter,the fuel is over 90% combusted.But in the exhaust system, you get 0% energy gains...
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I agree that the catalytic converter gives no power gains.
I must respectfully disagree with the 70% unburned figure out of the engine.
If the exhaust contained 70% unburned fuel, the catalytic converter would be burning MORE fuel than the engine. If this was true, the converter would thus reject more heat than the engine, and probably burn up the car in doing so.
I will try to find the unburned HC figures before and after the converter.
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Originally Posted by Rick & Connie
...Some claim you can't burn vaporised fuel. That it can't be ignited with a spark plug. But the fact is you can run an engine on propane and methane both. They are both vapor fuels. A jet engine uses high speed air flow to mostly vaporize it's fuel. Which is high grade kerosene. I realise that an internal combustion engine can't run on completly vaporized gasoline because of tar and varnish residues left behind after complete vaporization.
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If you are referring to my post, I said that a spark plug cannot ignite a 'lean' fuel/air mixture. I didn't say anything about 'vapor' one way or the other.
A gas turbine engine injects kerosene into a combustion chamber. The air in the chamber has to be slowed down enough that combustion can take place.
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Originally Posted by Rick & Connie
...In past times It was believed you couldn't run a fuel air mixture in a carburated engine any leaner then 13.5:1. Any less would cause damage, and it did. Then electronic fuel injection came along. Instead of partially misted fuel from the carburator, we now had well misted high pressure fuel leaving the throttle body injectors or manifold injectors at a ratio around 14:1. Leaner mixture, same power, same combustion tempratures, but better combustion efficiency. Now we have direct injection of the misted fuel directly entering the combustion chamber. Having no chance to seperate in the intake stream anymore,we now have fuel air mixtures in the range of 14.5:1 and 14.7:1.
The combustion efficiency has been improved again with very slight thermal increases and slightly more power.
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I will agree that a carbureted engine cannot run with a fuel/air mixture that is as lean as a fuel-injected engine. Yes, direct injection gives even better control, and it can be even a bit 'leaner.'
[Deleted by editing, erroneous information]
Engines today can burn a bit 'richer' to produce power, since they leave the cleanup of emissions to the cat. Too much unburned fuel, such as a spark plug that does not fire, will allow too much fuel into the converter and it will overheat.
Best Regards,
Jim