|
In a carburetor and in fuel injection, you can't just mix gasoline and oxygen and make the car start. You need to exactly meausure the amount of each for combustion with no fuel or air left over. This perfect performance meausures the cars power and mileage. The perfect mixture for a fuel injection engine is 14.7 air per 1 fuel or the ratio 14.7:1. If there is less air per 1 part of fuel than 14.7 the mixture is rich. If it is more than 14.7 then the mixture is lean. Usually in normal driving where the engine is within an acceptable range of heat the 14.7:1 is used. In a carburetor though this can be different. The carburetor can not meter the ratio as effectively. Some cars with carburetors have ratios as low as 12:1. The mixture on a carburetor is usually rich because fuel sometimes gets caught on the walls of the carb throat so it is lost. If an engine's ratio goes down to 10:1 then the engine loses power and a lean mixture makes excess air come out in the exhaust. The problem with a 14.7:1 mixture is that conditions change constantly. Car designers have put computers in that exactly use a ideal ratio for the condition so it can always run efficiently. If you want to know more, go to my Links page. |
|
