Combustion state-detecting system for internal combustion engines

U.S. Patent Number: 5390537

Abstract: A combustion state-detecting system for internal combustion engines has a crank angle sensor which generates a crank angle signal with a predetermined period shorter than a firing period of the spark plug whenever the crankshaft rotates through a predetermined angle. A value of the rotational speed of the engine is detected whenever the crank angle signal is generated. A rate of variation in the detected value of the rotational speed of the engine is calculated over the firing period of the spark plug, and an average value thereof is then calculated. The calculated average value of the variation rate is compared with the calculated variation rate, and a cumulative value of a difference between the calculated variation rate average value and the calculated variation rate is calculated when the calculated variation rate is on the larger deceleration side of the engine rotational speed with respect to the calculated variation rate average value. The calculated difference cumulative value is compared with a predetermined value to determine whether or not the engine is in a degraded combustion state, based on the comparison result.

Inventors: Kuroda; Shigetaka (Wako, JP), Maeda; Kenichi (Wako, JP), Sawamura; Kazutomo (Wako, JP), Maruyama; Hiroshi (Wako, JP)

Assignee: Honda Giken Kogyo Kabushiki Kaisha (Tokyo, JP)

Application Number: 08/149,913

Issued: 1995-02-21

Expired: 2007-02-21

Classes: 73/117.3

Field of search: 73/116,117.3 123/419,436 364/431.07,431.08

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