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.

A valve opening and closing timing control apparatus includes a drive-side rotational body, a driven-side rotational body, an intermediate lock mechanism which selectively switches between a lock state where displacement of a relative rotational phase of the driven-side rotational body relative to the drive-side rotational body is restrained in an intermediate lock phase and an unlock state where the lock state is released, and an electromagnetic valve. At a time of predetermined operation of an internal combustion engine, a value of the drive current is set as a boundary current, and the value of the drive current to be set as the boundary current differs, by a predetermined value, from a value of the drive current at a time when the unlock state was switched to the lock state due to the change of the drive current.

A valve timing controller includes: a driving side rotation member that rotates synchronously with a crankshaft of an internal combustion engine; a driven side rotation member that integrally rotates with a cam shaft of the internal combustion engine; a phase regulating mechanism with which a relative rotation phase of the driving and driven side rotation members around a rotation axis is set by a driving force of an electric motor; a phase sensing portion that acquires the relative rotation phase; and a phase controlling section that controls the electric motor to set the relative rotation phase based on an acquisition result by the phase sensing portion. The phase sensing portion includes a cam angle sensor, a reference determination sensor, and a pattern storage unit. The valve timing controller further includes a phase acquisition portion.

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 implementing control logic of a compression-ignition engine is provided. A controller outputs a signal to a injector and a variable valve operating mechanism so that a gas-fuel ratio (G/F) becomes leaner than a stoichiometric air fuel ratio, and an air-fuel ratio (A/F) becomes equal to or richer than the stoichiometric air fuel ratio, and to an ignition plug so that unburnt mixture gas combusts by self-ignition after the ignition plug ignites mixture gas inside a combustion chamber. The method includes steps of determining a geometric compression ratio and determining the control logic defining an intake valve close timing IVC. IVC (deg.aBDC) is determined so that the following expression is satisfied: if the geometric compression ratio is 10<17,

0.4234.sub..sup.222.926.sub.+207.84+CIVC0.4234.sub..sup.2+22.926.sub.167.84+C

where C is a correction term according to an engine speed NE (rpm),

C=3.310.sup.10NE.sup.31.010.sup.6NE.sup.2+7.010.sup.4NE.

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 apparatus includes a valve and an actuator. The valve has a portion movably disposed within a valve pocket defined by a cylinder head of an engine. The valve is configured to move relative to the cylinder head a distance between a closed position and an opened position. The portion of the valve defines a flow opening that is in fluid communication with a cylinder of an engine when the valve is in the opened position. The actuator is configured to selectively vary the distance between the closed position and the opened position.

In a system that selects a large-cam as a driving cam at a time of a start of an engine, when an engine stop request is output, it is determined whether there is a small-cam cylinder for which a small-cam is selected as the driving cam. In a case where it is determined that there is a small-cam cylinder, a switching command for switching the driving cam from the small-cam to the large-cam is output. When an engine start request is output, the above determination is performed again. In a case where it is determined that there is a small-cam cylinder, the switching command is output to all solenoid actuators again. In addition, the drive of the fuel injector is suspended until the switching operation of the driving cam is completed for all cylinders.

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.

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.