To: shashyazhi who wrote (1021 ) 2/8/1998 11:03:00 PM From: Ara Read Replies (2) | Respond to of 6464
Shashyazhi, what is an ''intact tract''? Anyways, it is physically impossible to store unburnt mixture in the exhaust because it is impossible to keep that ''computer controlled valve'' in the exhaust system closed at any RPM. You see, the exhaust in any internal combution engine has one object only and that is to GET RID OF EXHAUST GASSES. If you have unburnt gasses going out the exhaust too bad, burn them up to the max in the first place because they aint never coming back. Your theory would be like stuffing a potato up your tailpipe at low RPM and expecting the engine to run. Are you saying this would work? (the potato being that computer controlled valve of course). Let's say that was possible, how would the fuel system measure the air and fuel ratio going into the cylinder anyway,IMPOSSIBLE. There is UNWANTED reverse flow in all exhaust systems which is why exhaust systems are tuned, to get rid of it. The exhaust tuning does help an engine's fuel efficiency or performance. It is done in a number of ways,(equal length exhaust headers, free flowing mufflers, catalytic converters etc.)with one object, to get the burnt or unburnt gasses out of the engine as quickly as possible so that the intake cycle can start again. Another way the exhaust gasses could be used to help make an engine more efficient is as follows. Because you have UNIDIRECTIONAL exhaust flow in an engine, as the piston starts to go down on the intake stroke the exhaust valve (instead of being fully closed) is left open for a few degrees of cam rotation.The exhaust gasses then, which are travelling out (ONLY OUT) of the exhaust system create a vacuum effect and actually help to bring the air & fuel mixture into the cylinder faster. This is known as overlap and can only be done to a certain degree as too much would make for a rough running engine at low RPMs. I don't know how in any engine (including BAT's)you would want to induce reverse exhaust gas flow.