Honda Giken Kogyo Kabushiki Kaisha

Tomoya Furukawa

Yosuke Tachibana

Shun Masuda

Junichi Suzuki

Koichi Yoshiki

There is provided a valve timing control system for an internal combustion engine which is capable of reducing an aftershock subsequent to a deceleration shock, for which the execution of cleaning operation is responsible, and increasing the frequency of execution of the cleaning operation. The valve timing control system controls valve timing for opening and closing intake valves and/or exhaust valves by changing the cam phase of each intake cam and/or each exhaust cam relative to a crankshaft. A cam phase-varying device varies the cam phase by rotating a camshaft relative to the crankshaft. An ECU determines whether or not the engine is performing a fuel cut-off operation in which supply of fuel to the engine is stopped during deceleration. The ECU performs cleaning by forcibly driving the cam phase-varying device within a predetermined cam phase range when a predetermined delay time has elapsed after the deceleration fuel cut-off operation is started.

Valve timing control system for internal combustion engine

There is provided a valve timing control system for an internal combustion engine, which is capable of properly controlling valve timing while maintaining the accuracy of degradation determination of an oxygen concentration sensor or an exhaust gas-purifying device. The valve timing control system for an internal combustion engine includes a degradation-determining system that performs degradation determination of at least one of the oxygen concentration sensor and the exhaust gas-purifying device in a state in which the air-fuel ratio of a mixture supplied to the engine is controlled to a predetermined state, and controls valve timing by changing the cam phase. An ECU determines whether or not executing conditions for the degradation determination by the degradation-determining system are satisfied. When it is determined that the executing conditions for the degradation determination are satisfied, a change in setting of the target cam phase, which is to be executed in dependence on operating conditions of the engine, is restricted.

There is provided a valve timing control system for an internal combustion engine, which is capable of enhancing the accuracy of valve timing control. The valve timing control system for the internal combustion engine changes the cam phase of an intake cam a relative to a crankshaft to thereby control the valve timing of an intake valve The valve timing control system fixes a desired cam phase CAINCMD at a value CAINCMDFC during an fuel cut-off, and controls a cam phase change mechanism such that from a time t during the fuel cut-off, the cam phase is held at a value assumed at the time t Further, the valve timing control system calculates a learned value DCALEARN of the amount of deviation of an actual cam phase CAIN based on a plurality of values of the actual cam phase CAIN detected at and after the time t and the constant value CAINCMDFC of the desired cam phase CAINCMD (step S ).

There is provided a valve timing control system for an internal combustion engine, which is capable of properly setting the reference position of the cam phase by learning, and at the same time promptly establishing a learned value of the reference position when the learned value is lost, thereby accurately changing the cam phase for proper control of the valve timing of the engine. A cam phase change mechanism changes the cam phase. A reference value indicative of a reference position of the cam phase is learned at a predetermined learning speed based on the cam phase detected when the cam phase change mechanism is in a predetermined operative state, and the learned reference value (learned value) is stored in a RAM. When the loss of the learned value from the RAM is detected, a learning speed at the reference value is learned is corrected such that the learning speed is increased from the predetermined learning speed for a predetermined time period.

Growing community of inventors

Saitama-ken, Japan

Tomoya Furukawa