Mitsubishi Denki Kabushiki Kaisha

Masakazu Sugai

Akira Demizu

Ryoji Nishiyama

Yukinobu Nishimura

Hideaki Katashiba

Hitoshi Inoue

A microcomputer-based misfire detecting apparatus for a multi-cylinder internal combustion engine. A crank angle sensor is coupled to the engine for detecting first and second predetermined angular intervals set before and after a predetermined reference crank position close to a TDC preceding to combustion stroke in each of the cylinders. An acceleration detector is connected to the output of the crank angle sensor for determining an acceleration based on a time ratio between times taken for a crank shaft to rotate through the first and second predetermined angular intervals, respectively, from the output signal of the crank angle sensor. A misfire occurrence detector is connected to the acceleration detector for detecting misfire occurring in the engine cylinder on the basis of the output signal of the acceleration detector.

Misfire detecting apparatus for a multi-cylinder internal combustion

A misfire detection device for a multi-cylinder internal combustion engine detects levels of angular acceleration .beta. of the crankshaft corresponding to predetermined phase intervals of respective cylinders. Further, the differences .DELTA..beta. between the levels of angular acceleration corresponding to successively ignited cylinders are calculated as the combustion condition parameters corresponding to respective cylinders, and when the absolute variance .DELTA..beta.R of the levels of combustion condition parameter (i.e., difference of acceleration .DELTA..beta.) corresponding to cylinders whose ignition timings are separated by 360 degrees of the crank angle is continuously less than a predetermined judgment level, an occurrence of continuous misfires is detected.

Device for detecting continuous misfires of a multi-cylinder internal

An engine control device comprises: crank angle sensor provided for the cylinders of an engine; cylinder internal pressure sensor for detecting the internal pressures of the cylinders according to the output signals of the crank angle sensor; pressure normalizing unit for normalizing the cylinder internal pressures thus detected, according to the cylinder internal pressure which is obtained when the engine is in standard state; engine speed detector; charge efficiency calculating unit for calculating the charge efficiencies of the cylinders by using the output signals of the pressure normalizing unit and the engine speed detector; operating condition detecting unit for detecting the outputs of the pressure normalizing unit and the engine speed detector as operating conditions, calculation control unit for calculating the air/fuel ratio and the ignition timing of each cylinder according to the operating conditions; and adjusting unit for adjusting the air/fuel ratios and ignition timing of the cylinders according to the output of the calculation control unit, thereby to control the air/fuel ratios and ignition timing of the cylinders with high accuracy.

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Himeji, Japan

Masakazu Sugai