Honda Giken Kogyo Kabushiki Kaisha

Masatoshi Obata

Yasunari Seki

Yuzuru Koike

Norio Satoh

Takashi Sato

A method for detecting an irregularity in the valve-timing changeover in an engine having a valve operating mechanism capable of operating the intake valves or exhaust valves, or both, in a different manner, known as valve timing, such as the magnitude of valve lift or the duration the valve remains open, for improving the operation of the engine at different engine speeds. The method compares the oil pressure in the supply passage to the valve timing changeover mechanism with the oil pressure that should exist after the changeover caused by the latest instruction to determine an irregularity if the pressures are not equal. A time delay may be used to accommodate the inherent time lay in the changeover to avoid a premature determination of an irregularity. An alarm may be energized or a fail-safe procedure initiated when an irregularity is detected.

Method for detecting an irregularity in valve-timing changeover in an

An exhaust gas recirculation system for an internal combustion engine employs a vacuum actuator for a control valve in the exhaust gas recirculation passageway. A suction conduit to the actuator contains a magnetic valve for venting the suction conduit to atmosphere. The operating means for the magnetic valve includes a vacuum switch responsive to suction pressure in the engine intake passage modified by atmosphere pressure compensation means. A second magnetic valve responsive to engine speed also vents the suction conduit to atmosphere.

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Tochigi, Japan

Masatoshi Obata