|LANCE’S CORNER – AUTO REPAIR HELP|
FUEL INJECTION BASICS
Catalytic converters are fantastic emission control devices because they have the ability to change the harmful emissions of a vehicle into carbon dioxide and water vapor. In order to work efficiently, catalytic converters require a precise air/ fuel mixture. The ratio of fourteen parts air to one part fuel, has been found to provide the most efficient catalytic converter operation. Any variation to the air/fuel mixture, too much or too little fuel, will affect the function of the catalytic converter, resulting in costly auto repairs. Because of this, engineers had to design a fuel system that had the ability to maintain a constant air/fuel ratio throughout the engines operating range and conditions. Computer controlled carburetors were first used, but their ability to provide fuel control to meet all vehicle operating conditions was limited. Electronic fuel injection systems were found to provide a wider range of fuel control and the added benefit of better fuel economy and increased performance over carbureted systems.
two basic types of fuel injection systems used on passenger cars and
light trucks, multiport fuel injection and throttle body fuel injection.
Because they provide lower emissions and more efficient operation, most
vehicles today are equipped with multiport fuel injection systems.
body injection systems use an injector or a pair of injectors placed
in the throttle body to deliver fuel to the engine. Fuel is sprayed
into the intake air of the engine and is distributed to the individual
cylinders by the intake manifold. As in the multiport fuel injection
system, the injectors are pulsed width operated to maintain proper air/fuel
ratio. This system was used as a less expensive alternative to multiport
fuel injection but was not as efficient. Automotive emission control
regulations that went into effect for the 1996 model year, all but eliminated
the use of throttle body injection on automobiles and light trucks.
(Lance owned his own auto repair shop for 30 years before retiring in 2006.)