The Lean Hunting Phenomenon in Gasoline Engines - part 2

The hunting phenomenon which occurs at the lean air-fuel ratio and under light load conditions was studied in the previous paper and it was disclosed that this was not “mechanical hunting” and the fuel flow delay into the cylinder had a dominant effect on this “lean hunting”. This paper describes first, the experiments which demonstrate that such a fuel flow delay can occur by changing the throttle position sinusoidally in various periods, and that Pmax (the maximum pressure in the cylinder) responds quite differently according to the magnitude of the air-fuel ratio; secondly, the effects of ignition energy and ignition timing on the lean hunting were also studied.