Importance

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Abstract

A method and system for adaptive correction of the amount of fuel supplied in two-stroke combustion engines which during a continuous operation period regulates the air-fuel mixture regulated by increments in the lean direction (.DELTA.F.sup.-) or in the rich direction (.DELTA.F.sup.+), whereby fuel amounts (F) are established which cause knocking (KNOCK) and four-stroking or misfiring (4-ST), respectively. These limit values are stored as a lean limit value M.sub.FK and a rich limit value M.sub.F4ST, respectively. For further operation of the combustion engine, a corrected fuel amount F.sub.koor, is used, which is corrected in relation to the fuel amount F.sub.tab given from an empirically determined value stored in a map, and dependent on the established lean limit value M.sub.FK and the rich limit value M.sub.F4ST, respectively. The fuel amount (F) supplied will suitably be given according to the function: F=F.sub.korr =M.sub.FK +K.multidot.(M.sub.F4ST -M.sub.FK), where K is a margin factor which defines if further operation of the engine will be controlled having an equidistant margin towards a knocking condition or a four-stroking or misfire condition, i.e., if K is set to a value of 0.5, or if further operation will be controlled toward leaner air-fuel ratios, i.e., if K is set to a value below 0.5. Further control could thus be made having a fixed relative margin towards a knocking condition as well as a four-stroking condition.

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First Claim