Methods and systems are provided for adjusting an oil pressure supplied to an engine and a variable cam timing (VCT) responsive to a condition of the VCT system. In one example, a method may include adjusting the oil pressure based on engine speed, engine load, and engine oil temperature, and responsive to a request to shift the VCT system during specific engine operating conditions, increasing the oil pressure to an upper threshold oil pressure for the duration of the shift.

An electronic control unit of a control device for an internal combustion engine executes, for a first cycle, first drive processing for controlling an actuator such that a pin drive operation is executed for switching from a first cam to a second cam, executes second drive processing for controlling the actuator such that the pin drive operation is executed again for a second cycle, and executes abnormality determination processing for determining that a cam switching mechanism has an abnormality in a case where a pin returns to a reference position by using a pin return section following a cam switching section of the first cycle after the execution of the first drive processing and the pin returns to the reference position by using the pin return section following the cam switching section of the second cycle after the execution of-the second drive processing.

Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.

A method of phasing the opening and closing of internal combustion engine intake and exhaust valves relative to the rotation of the crankshaft is based upon changes in engine speed, engine load and ambient relative humidity. During certain conditions of higher humidity, in order to maintain good combustion stability and thus overall engine operation, it is necessary to reduce intake and exhaust valve overlap by adjusting the phase of the intake and exhaust camshafts. This is achieved by utilizing a set of cam position reference values and constraints based upon engine speed, engine load and humidity that are contained in lookup tables that adjust and limit cam position and valve overlap. Generally speaking, in order to maintain optimum engine performance, intake and exhaust valve overlap is reduced with higher ambient humidity and vice versa.

Methods and systems are provided for adjusting an oil pressure supplied to an engine and a variable cam timing (VCT) responsive to a condition of the VCT system. In one example, a method may include adjusting the oil pressure based on engine speed, engine load, and engine oil temperature, and responsive to a request to shift the VCT system during specific engine operating conditions, increasing the oil pressure to an upper threshold oil pressure for the duration of the shift.

Provided is a control device for an internal combustion engine equipped with a cam switching device including a cam groove provided on the outer peripheral surface of a camshaft and an electromagnetic solenoid type actuator capable of protruding, toward the camshaft, an engagement pin that is engageable with the cam groove. The control device is configured, in causing the cam switching device to perform a cam switching operation, to perform energization of the actuator such that the engagement pin is seated on a forward outer peripheral surface, and to more lower, when an electric current (coil current) flowing through the actuator as a result of the energization is greater, an average electric voltage per unit time applied to the actuator in protruding the engagement pin toward the cam groove from the forward outer peripheral surface.

A method for cleaning a continuously variable valve timing (CVVT) system for removing foreign materials includes: switching a target operating value of the CVVT system to a predetermined setting value within a set operating region and performing cleaning of the CVVT system; and determining whether a valve timing control learning request exists for the CVVT system, and, when the valve timing control learning request exists, aborting the cleaning.

An oil supply control device for an engine includes: a hydraulic controller which outputs a control value to an adjusting device to cause a detected hydraulic pressure detected by a hydraulic pressure sensor to coincide with a predetermined hydraulic pressure value; a determination portion which compares an output control value output from the hydraulic controller to the adjusting device when the detected hydraulic pressure coincides with the predetermined hydraulic pressure value and a control value stored in a memory, to determine whether or not a difference between the output control value and the stored control value lies within a predetermined allowable range; and a device controller which allows activation of a hydraulic actuating device when an oil temperature is not lower than a first temperature in a case where the difference lies within the allowable range, inhibits activation of the hydraulic actuating device when the oil temperature is lower than a second temperature higher than the first temperature in a case where the difference does not lie within the allowable range, and allows activation of the hydraulic actuating device when the oil temperature is not lower than the second temperature in a case where the difference does not lie within the allowable range.

A method of phasing the opening and closing of internal combustion engine intake and exhaust valves relative to the rotation of the crankshaft is based upon changes in engine speed, engine load and ambient relative humidity. During certain conditions of higher humidity, in order to maintain good combustion stability and thus overall engine operation, it is necessary to reduce intake and exhaust valve overlap by adjusting the phase of the intake and exhaust camshafts. This is achieved by utilizing a set of cam position reference values and constraints based upon engine speed, engine load and humidity that are contained in lookup tables that adjust and limit cam position and valve overlap. Generally speaking, in order to maintain optimum engine performance, intake and exhaust valve overlap is reduced with higher ambient humidity and vice versa.

Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.