The mass ration of air/fuel present during combustion is called the air-fuel ratio or AFR. Basically, within a vehicle's combustion chamber, the mixture is chemically balanced when all the fuel is combined with all the free oxygen. This air fuel ration is called the stoichiometer mixture or stoich. For anti pollution and for performance tuning reasons the air-fuel ratio is a critical measure. Alternatively, Lamba is used to represent AFR. The fuel delivery system in a high performance engine must be appropriately tuned for optimum performance that allows peak torque and horsepower.
It is only when the air fuel ratio is in balance for the air flow ingested by the engine that the highest power is achieved. This happens when the EFI engine control module or ECM, engine management system or carburetor is adjusted for right fuel delivery. The engine mass air flow is determined by engine speed (rpm), efficiency and throttle opening. The quantity of fuel injection can be calculated by the ECM provided that the mass air flow or MAF is given. The speed density calculation will look up the fuel injector pulse width from a tablet that can be adjusted to achieve the proper air fuel-ratio for steady state operation. This is true if the ECM employs a manifold air pressure sensor.
An air fuel ratio gauge is used to be alerted if the engine is running lean at high load. In this condition, there is a big possibility to have an increase in deterioration – exhaust gas temperature shoots through the roof and you can expect broken valves, damaged spark plugs, damaged pistons, blown head gaskets, melted cat converters and other nasty events. So never keep a damaged air fuel ratio gauge. Parts Trail has something for you from AEM. The AEM air fuel ratio gauge is one of the aftermarket products available here with us. Look for more AEM products by browsing through our online catalog.
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