Various embodiments include a method for detecting deviations occurring in the valve drive of an internal combustion engine comprising: measuring dynamic pressure oscillations of intake air in an air intake tract of respective internal combustion engine during operation; calculating an inlet valve stroke phase difference and/or an outlet valve stroke phase difference based on the measured dynamic pressure oscillation; calculating a valve stroke phase deviation value with respect to a valve stroke phase reference value based on the calculated phase difference; and calculating a first valve drive deviation value based on the valve stroke phase deviation value.

Various embodiments include a method for identifying valve stroke phase differences during operation comprising: measuring dynamic pressure oscillations in the air intake tract; generating a corresponding signal; acquiring a crankshaft phase angle; acquiring the phase position and the amplitude of a signal frequency of the oscillations based on the pressure oscillation using discrete Fourier transformation; acquiring a line of an equal phase position and of equal amplitude of the signal frequency reflecting the inlet and the outlet stroke phase difference using reference lines; acquiring a common intersection point of a line of equal phase position and a line of equal amplitude by projection into a common plane; and determining the stroke phase differences and from the common intersection point.

Various embodiments include a method for identifying an inlet and an outlet valve stroke phase difference comprising: measuring pressure oscillations during operation; generating a corresponding signal; determining a corresponding crankshaft phase angle; applying a discrete Fourier transformation to the pressure signal to determine amplitudes of selected frequencies in relation to the crankshaft phase angle; determining lines of equal amplitudes of the frequencies based on the amplitudes depending on the phase differences using reference lines; determining an intersection of the lines by projection into a common plane; and determining the inlet valve stroke phase difference and the outlet valve stroke phase difference from the determined common intersection point of the lines of equal amplitudes of the selected signal frequencies.

An arrangement for cylinder detection in a four-stroke internal combustion engine is disclosed. The arrangement comprises a first disc connected to a crankshaft, the first disc comprising a first mark (M11-M13) within each an interspace angle (), and a second disc connected to a camshaft and comprising one second mark (M21-M26) per number of cylinders. The first mark (M11-M13) is arranged on a first disc, or the plurality of first marks (M11-M13) are arranged in relation to each other on the first disc, and the second marks (M21-M26) are arranged in relation to each other on the second disc such that for each interspace angle () the relevant first mark (M11-M13) is detectable by a first sensor and the relevant second mark (M21-M26) is detectable by a second sensor at different relative rotational positions between the first disc and the second disc.

A multiple-cylinder diesel engine system comprises an intake valve and an exhaust valve for each of the multiple cylinders. A valve control system is connected to selectively deactivate an intake valve and an exhaust valve for a selected cylinder. A fuel injection control system is connected to selectively deactivate fuel injection to the selected cylinder while increasing fuel to firing cylinders. The multiple cylinder diesel engine enters a cylinder deactivation mode whereby the valve control system deactivates the intake valve and the exhaust valve and the fuel injection control system deactivates the fuel injection to the cylinder while continuing to fire other cylinders of the multiple cylinder diesel engine. The valve control system selectively opens the deactivated intake valve to relieve a negative pressure condition in the deactivated cylinder. Alternatively, the valve control system opens the deactivated exhaust valve to relieve a negative pressure condition in the deactivated cylinder.

An internal combustion engine includes: a crankcase that supports a crankshaft rotatably about a rotational axis; a cylinder block connected with the crankcase and including at least one pair of cylinders that sandwich a valve chamber therebetween in an axial direction of the crankshaft, the valve chamber housing therein a valve actuating mechanism that connects a camshaft to the crankshaft; a detected member disposed between crank pins corresponding to the pair of cylinders, the detected member rotating integrally with the crankshaft; and a detection sensor disposed to face a trajectory of the detected member and generating a pulse signal in accordance with movement of the detected member. Accordingly, the internal combustion engine can avoid displacement of a nearby part and enlargement of the crankcase as much as possible, while allowing the detected member to be increased in size.

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 variable valve system including a crank angle sensor that measures a rotation angle of a crankshaft, a cam angle sensor that measures a rotation angle of a camshaft coupled to the crankshaft and which opens and closes valves, and a controller that controls the internal combustion engine. At least one of the crank angle sensor or the cam angle sensor is configured as an absolute angle sensor that measures an absolute rotation angle and outputs a voltage signal corresponding to this rotation angle. The controller is configured to perform a correction operation that corrects a rotation angle value calculated based on the voltage signal.

In a control device and a control method for a variable valve timing mechanism according to the present invention, the rotational phase of a camshaft is measured based on the cam angle signal and crank angle signal upon receiving each pulse of the cam angle signal, and the rotational phase change over time within a period of the cam angle signal is measured based on the motor angle signal. It is decided whether the cam angle signal and/or crank angle signal has a prescribed pulse pattern at a diagnostic timing that comes after the last pulse of the cam angle signal. When this decision result is positive, it is then decided whether the motor angle sensor operates normally or abnormally based on the rotational phase and the amount of rotational phase change that are measured when the last pulse of the cam angle signal is received before the diagnostic timing.

A method is disclosed for adaptively controlling an engine system of a motor vehicle comprising the steps of evaluating the outputs from angular position sensors associated with inlet and exhaust camshafts of an engine of the engine system to establish whether differences between the currently measured positions and previously saved positions are the result of elongation of an endless drive used to drive the camshafts or due to some other reason. If it is confirmed that the differences are due to elongation of the endless drive then the measured values of angular position are used in the control of a number of engine functions.