PURPOSE: To drive a gasoline engine in a state of coming nearer to the limitation of stable driving at each cylinder after detecting the extent of ionic current density, on the basis of a well-known knowledge that density of an ionic current flowing into a spark plug is the larger in variations, the nearer to the critical driving state of a lean air-fuel ratio.
CONSTITUTION: A whole area air-fuel ratio sensor 201 is installed in an exhaust passage 200 of an engine 100. In addition, a combustion state detector 500 is composed of a backstop means 22 of an ignitor 400, an ionic current detecting voltage generating means 4, a secondary voltage divider 5, a damping characteristic detector circuit 6 and a variation degree discriminator circuit. In succession, a fuel injection system 301 is installed at each intake air passage 300 at respective cylinders. Subsequently, a stable driving limitation at each cylinder is detected by the combustion state detector 500. At a controller 7, a fuel injection quantity is leanly regulated up to a critical air-fuel ratio nearby the stable driving limitation, while a tentative lean air-fuel ratio is controlled after rewriting it to a critical lean air-fuel ratio.
YOSHIDA HIDEJI
MATSUBARA YOSHIHIRO
ITO YASUO
| JPS60187724A | 1985-09-25 | |||
| JPS5946352A | 1984-03-15 | |||
| JPS6050973A | 1985-03-22 |