When the amount of air that is admitted to the engine
is such that it is just enough to fully burn the injected fuel,
the engine operation is termed Bstoichiometric.[ The
actual fuel-to-air ratio divided by the stoichiometric fuelto-
air ratio is called the (fuel/air) equivalence ratio .
Thus, ¼ 1 denotes stoichiometric operation. If G 1,
more air is aspirated by the engine than is necessary for
complete combustion. This is termed lean operation. The
reverse, > 1, is termed rich operation.