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 internal combustion engine includes a cam-actuated rocker arm assembly with a solenoid-actuated latch that provides for cylinder deactivation or variable valve actuation. The solenoid has an inductance that varies significantly in relation to the position of a latch pin as it translates between latching and non-latching configurations. A sensor is positioned to monitor a current or a voltage in a circuit that includes the solenoid. Diagnostic information relating to the operation of the rocker arm assembly is determined by comparing data collected from the sensor over a first period to data collected from the sensor over a second period.

A vehicle includes a variable displacement engine, a conduit, a sensor, and a controller. The variable displacement engine has a plurality of cylinders. The conduit is configured to channel exhaust gas away from the cylinders. The sensor is disposed within the conduit and is configured to measure an amount of particulate matter within the exhaust gas. The controller is programmed to, in response to a command to run a diagnostic test, operate each of the plurality of cylinders independently to produce an exhaust gas stream for each cylinder and measure the amount of particulate matter within each of the exhaust gas streams.

In one embodiment, a system includes an engine control system configured to control an engine. The engine control system comprises a processor configured to receive a vibration signal sensed by a knock sensor disposed in an engine. The processor is further configured to correlate the vibration signal with a fingerprint having at least an ADSR envelope indicative of the operating event of a valve train of the combustion engine, analyze the vibration signal with a statistical valve train model, or a combination thereof. The processor is also configured to detect if the operating event has occurred based on correlating of the noise signal with the fingerprint, based on analyzing the vibration signal with a statistical valve train model, or a combination thereof, and to control the valve train based on the operating event.

In one embodiment, a method is provided. The method includes receiving a signal representative of an engine vibration transmitted via a knock sensor, wherein the knock sensor is disposed in an engine. The method additionally includes deriving a valve wear measurement during operation of the engine based on the signal. The method further includes communicating the valve wear measure.

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.

A method for diagnosing an engine system including a continuous variable valve duration (CVVD) apparatus, a driving unit of the CVVD apparatus including a first driving unit and a second driving unit, a CVVD position detector configured to detect a position of the CVVD apparatus, a camshaft position detector configured to detect a position of a camshaft, a front lambda detector configured to detect a lambda value at front of intake valve, and a controller may include the steps of starting the engine, detecting measured values of the front lambda detector during combustion of first to fourth cylinders (first to fourth lambda values), determining whether CVVD driving unit is misaligned according to the detected first to fourth lambda values, and generating a warning notification when the CVVD driving unit is determined to be misaligned.

A vehicle includes a variable displacement engine and a controller. The variable displacement engine has a plurality of cylinders and is configured to operate at a commanded air-fuel ratio. The controller is programmed to, in response to a command to perform a diagnostic test, operate the engine such that each of the cylinders is shut down for a portion of the diagnostic test while one or more of the remainder of the cylinders remain operating. The controller is further programmed to, in response to a deviation from the commanded air-fuel ratio exceeding a threshold while a first of the cylinders is shut down during the diagnostic test and a subsequent command to decrease the number of operating cylinders, shut down one or more of the plurality of cylinders other than the first of the cylinders.

A vehicle includes a variable displacement engine, a conduit, a sensor, and a controller. The variable displacement engine has a plurality of cylinders. The conduit is configured to channel exhaust gas away from the cylinders. The sensor is disposed within the conduit and is configured to measure an amount of particulate matter within the exhaust gas. The controller is programmed to, in response to a command to run a diagnostic test, operate each of the plurality of cylinders independently to produce an exhaust gas stream for each cylinder and measure the amount of particulate matter within each of the exhaust gas streams.

A method of operating an internal combustion engine of a type that has a combustion chamber, a moveable valve having a seat formed in the combustion chamber, a camshaft on which a cam is mounted, and a rocker arm assembly having a rocker arm and a cam follower configured to engage the cam as the camshaft rotates. The method includes obtaining rocker arm position data, using the rocker arm position data to obtain camshaft position information, and using the camshaft position information in an engine management operation.