Methods and systems are provided for diagnosing a cylinder valve deactivation mechanism in an engine system having cam-actuated valves. Movement of a latch pin of the deactivation mechanism is inferred from an induction current generated by a solenoid coupled to the latch pin, and the inferred movement is used to diagnose operation of cylinder valve deactivation mechanism. The inferred movement and a profile of the induction current is also used to estimate camshaft and crankshaft timing for improved cylinder fuel delivery in the absence of a camshaft sensor.

An abnormality diagnosis system of an internal combustion engine that is installed on a vehicle and includes an actuator includes an electronic control unit. The electronic control unit receives vehicle outside information concerning a period of time for which the vehicle speed is less than a predetermined value, and determines whether the period for which the vehicle speed is less than the predetermined value is expected to be equal to or longer than a length of time required for an abnormality diagnosis of an abnormality diagnosis target device. The electronic control unit activates the actuator and starts the abnormality diagnosis as the vehicle speed becomes lower than the predetermined value, when it determines that the period for which the vehicle speed is lower than the predetermined value is expected to be equal to or longer than the time required for the abnormality diagnosis of the target device.

In a control device for an engine, the engine includes combustion chambers, ports connected to the combustion chambers, and valves that open and close areas between the combustion chambers and the ports. The control device includes an electronic control unit that is configured to execute an anti-freezing operation of performing control to fully close the valves or make the valves be in a state of being opened with a lift amount of 1 mm or more, in a case where temperatures around the valves are lowered to a predetermined temperature range after the engine is stopped, or in a case where an outside air temperature when the engine is stopped is equal to or lower than a predetermined temperature. The predetermined temperature range is a temperature range in which an upper limit value is lower than 10 C., and the predetermined temperature is lower than 5 C.

A control device for an internal combustion engine is configured to: execute a first decompression operating processing such that a decompression operating state is selected in a first engine speed region that passes in the course of engine stop; execute a decompression stop processing such that a switching from the decompression operating state to a decompression stop state is performed in the course of the engine stop after passage of the first engine speed region; when a temperature correlation value is greater than or equal to a threshold value upon an engine start-up request, execute a second decompression operating processing such that the decompression operating state is selected in a second engine speed region that passes in the course of engine start-up before the start of fuel injection. When the temperature correlation value is smaller than the threshold value, the second decompression operating processing is not executed.

A decompression pin is inserted into a swing range of an end portion of a rocker arm, on a side which is supported by a lash adjuster, when the rocker arm has been inclined toward a direction in which a valve is opened. The decompression pin comes into contact with the end portion of the rocker arm 4 when the rocker arm is inclined toward a direction in which the valve is closed, and thereby restricts the rocker arm from returning to a position at which the valve is completely closed, and the valve becomes in a slightly opened state even in a compression stroke.

An oil drain preventing device for a continuously variable valve timing apparatus includes: an advance angle oil passage connected to a continuously variable valve timing (CVVT) journal from an an oil control valve (OCV) groove to which an oil control valve (OCV) is mounted to supply an oil supplied from a hydraulic pump to a continuously variable valve timing (CVVT) apparatus; a retard angle oil passage connected to the CVVT journal from the OCV groove; and a valve unit mounted to the advance angle oil passage and the retard angle oil passage between the oil control valve and the CVVT journal for preventing the oil supplied to the continuously variable valve timing apparatus from being drained by selectively opening/closing the advance angle oil passage and the retard angle oil passage according to a starting ON or a starting OFF of the engine.

Provided is a control device for controlling an internal combustion engine including a fuel injection valve, an ignition device, and a variable valve operating device configured to switch between a base opening/closing mode of an intake valve and a continuous valve opening mode. The control device is configured to execute a cold start control at a cold start. The cold start control includes: a startability improvement processing executed in a predetermined number of cycles after the start of cranking; and a combustion start processing executed after this predetermined number of cycles. In the startability improvement processing, the continuous valve opening mode is selected in at least an expansion stroke and an exhaust stroke, and fuel injection is executed without ignition. In the combustion start processing, the base opening/closing mode is selected continuously during one cycle, and ignition is executed.

Provided is a hybrid vehicle that includes a power train including an internal combustion engine equipped with a plurality of cylinders and a drive motor unit. The drive motor unit includes an electric motor coupled to the internal combustion engine without a clutch. The internal combustion engine includes one or more decompression devices that are each installed for a subset of one or more cylinders and that operate to release compression pressure in the subset of one or more cylinders in at least one of the course of an engine stop and course of an engine start-up in which combustion is not performed. The subset of one or more cylinders are selected such that, when the one or more decompression devices are operating, compression is not produced sequentially in cylinders that are adjacent to each other in terms of the firing order.

Using existing phaser control valve and a solenoid to create a pumping chamber which provides enough oil pressure to disengage a locking pin at all conditions.

A method for controlling intake and exhaust valves of an engine includes: Controlling opening and closing timings of the intake and exhaust valves by an intake continuous variable valve timing (CVVT) device and an exhaust CVVT devices; determining, by a controller, target intake and exhaust opening durations of the intake and exhaust valves, and target opening and closing timings of the valves based on an engine load and an engine speed; modifying current intake and exhaust opening durations based on the target opening durations via an intake continuous variable valve duration (CVVD) device and an exhaust CVVD device; adjusting opening or closing timings of the valves to the target opening or closing timings of the valves while maintaining the modified opening durations of the valves.