Carburetor Q?

Question

A carburetor is a device attached to an autombile engine in which gasoline and air are mixed prior to being burned. A "lean" fuel/air mixture contains less fuel than a rich fuel/air mixture. Which type of mixture would result in the cleanest automobile exhaust? Why?

I am primarily looking at carbon monoxide.

Answer 1

It depends on which pollutant component of combustion you look at. Carbon monoxide, sulfur dioxide, oxides of nitrogen all change levels independantly of each other. Many times one will increase as another decreases as you change the ratio from ideal. Besides, with current engine building practices, lean ratios mean higher heat which is detrimental to an engine, especially at the exhaust valve(s), piston crown and top compression ring. Rich ratios lead to plug fowling which then increases the level of unburned hydrocarbons (read green house gases). Stick with the accepted air/fuel ratio for now or engineer an engine that is approacing a much higher heat efficiency than is presently available.

Answer 2

Honest truth is... most cars nowadays don't use carburetors at all. They use fuel injection or direct injection.

But to answer your question... the answer is neither. There is an ideal mix ratio that results in maximum combustion (it won't be perfect) that depends on dispersal, ignition, shape of cylinder and combustion chamber, and all that.

Running rich is worse than running lean at least for the environment, but running lean heats up the engine severely and can cause premature failures. There's a fine line there.

Answer 3

The perfect mixture is around 14 to 1. Lean burns cleaner but can damage a motor, rich burns dirty but will not damage a motor. To far in either direction and combustion can't take place.

Answer 4

Obviously, the leaner the mixture, the less emissions you will have, HOWEVER, making your mixture to lean can cause serious engine damage, not to mention the deterioration in your car's performance.