automotive/marine stoichiometry
A mixture is the working point that modern engine management systems employing fuel
injection attempt to achieve in light load cruise situations. For gasoline fuel, the
stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel.
Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than
14.7 to 1 is a lean mixture - given perfect (ideal) "test" fuel (gasoline consisting
of solely n-heptane and iso-octane).
As engine components age, parts-gaskets-seals deteriorate, intake,exhaust, sensors, ect.
The Brain - ECM compensates if you have a vacumn leak by adding more fuel,as the O2 reports
a lean condition. If an injector is stuck open the engine runs rich, and the ECM compensates
by restricting the injector electrical pulses that open its pintols. When these factors get
out of the range of compensation, the ECM sends out a check engine light signal.
Heres good reading:
http://www.youtube.com/watch?v=5WnM_NsOtd8
http://www.youtube.com/watch?v=cARQ0jZZ4Qc
Bills86e
A mixture is the working point that modern engine management systems employing fuel
injection attempt to achieve in light load cruise situations. For gasoline fuel, the
stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel.
Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than
14.7 to 1 is a lean mixture - given perfect (ideal) "test" fuel (gasoline consisting
of solely n-heptane and iso-octane).
As engine components age, parts-gaskets-seals deteriorate, intake,exhaust, sensors, ect.
The Brain - ECM compensates if you have a vacumn leak by adding more fuel,as the O2 reports
a lean condition. If an injector is stuck open the engine runs rich, and the ECM compensates
by restricting the injector electrical pulses that open its pintols. When these factors get
out of the range of compensation, the ECM sends out a check engine light signal.
Heres good reading:
http://www.youtube.com/watch?v=5WnM_NsOtd8
http://www.youtube.com/watch?v=cARQ0jZZ4Qc
Bills86e
