The systems and methods described herein provide an approach for cam phase angle control where an axial or rotational position of an actuator of a cam phaser has a direct relationship to the phase angle of the cam shaft, allowing for accurate cam phasing without the need for cam shaft or crank shaft position sensors. Providing phase angle adjustability without the need for crank shaft or cam shaft position sensors enables control of phase angle solely by sensing the axial or rotational position of the actuator of the cam phaser.

An exhaust valve system for a two-stroke internal combustion engine having: at least one exhaust valve movable between open and closed positions; an actuator for moving the at least one exhaust valve; a valve position sensor; a controller communicating with the actuator and the valve position sensor. The controller being programmed for: controlling the actuator to attempt to move the at least one exhaust valve to a desired one of the open and closed positions; determining if the at least one exhaust valve has failed to reach the desired position based on the position of the at least one exhaust valve sensed by the valve position sensor; and controlling the actuator to move the at least one exhaust valve to an intermediate position when the at least one exhaust valve has failed to reach the desired position.

Systems and techniques for identifying abnormal exhaust valve performance of an internal combustion engine may include receiving exhaust passage temperature signals from a plurality of exhaust passage temperature sensors, each exhaust passage being fluidly connected to one or more exhaust valves of the internal combustion engine, the exhaust passage temperature signals being indicative of respective exhaust passage temperatures. The method may further include comparing one or more of the exhaust passage temperatures, identifying a caution exhaust passage temperature, from one or more of the exhaust passage temperatures, that deviates from one or more of the other one or more exhaust passage temperatures, and outputting an abnormal exhaust valve performance indication based on identifying the caution exhaust passage temperature.

Methods and systems are provided for a diagnostic routine of a variable displacement engine (VDE) of a vehicle to detect non-deactivated valves of deactivated cylinders due to a degraded valve deactivation mechanism. In one example, a method comprises, during operation of the VDE with one or more cylinders of the VDE deactivated, calculating a variation in a fast-sampled signal outputted by one or more exhaust gas oxygen (EGO) sensors of the VDE over a plurality of engine cycles; determining that the variation is greater than the threshold variation; and in response, indicating that valves of the one or more cylinders are not deactivated. A second method comprises estimating a throttle air flow rate and an engine air flow rate of the VDE; and indicating non-deactivated valves of one or more deactivated cylinders if the throttle air flow rate exceeds the engine air flow rate by a threshold.

A technique for testing a pushrod valvetrain in an engine includes replacing an original pushrod with an instrumented pushrod (IPD) which includes a sensor configured to measure strain and/or motion. The engine is then operated, and the output of the sensor is monitored for anomalies. Diagnosis and repair of identified defects may then follow.

There is provided a variable valve apparatus including: a plurality of rocker arms; a coupling pin disposed in a housing hole of the rocker arm closer to one side; a release pin disposed in a housing hole of the rocker arm closer to the other side; a pressing member; a transmission member; and a push-back member disposed so as to push back the transmission member from the other side. The pressing member is configured to push the coupling pin into the housing hole of the rocker arm closer to the other side to couple the plurality of rocker arms. The transmission member is configured to push back the coupling pin into the housing hole of the rocker arm closer to the one side to release a coupling of the plurality of rocker arms.

A system for selectively activating and deactivating cylinders includes a first cylinder positioned in a cylinder block. A first intake or exhaust valve is coupled to the first cylinder and is actuated by a first coupling mechanism. A first oil control solenoid is coupled to the first coupling mechanism, the first oil control solenoid deactivates the first coupling mechanism to maintain the first intake or exhaust valve in a closed position. A second cylinder is positioned in the cylinder block, and a second intake or exhaust valve is coupled to the second cylinder. The second intake or exhaust valve is actuated by a second coupling mechanism. A second oil control solenoid is coupled to the second coupling mechanism, the second oil control solenoid deactivates the second coupling mechanism to maintain the second intake or exhaust valve in a closed position. The first oil control solenoid and the second oil control solenoid have different operating parameters.

A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end and a second end, at least one slider pad connected to the first arm near the second end of the first arm, a second arm also having a first end pivotally connected near the first end of the first arm along a pivot axle, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employs a sensor attached to one of the arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the detected movement.

A classifier capable of predicting if cylinder valves of an engine commanded to activate or deactivate failed to activate or deactivate respectively. In various embodiments, the classifier can be binary or multi-class Logistic Regression, or a Multi-Layer Perceptron (MLP) classifier. The variable displacement engine can operate in cooperation with a variable displacement engine using cylinder deactivation (CDA) or skip fire, including dynamic skip fire and/or multi-level skip fire.

A method of providing diagnostic information for an electromagnetic latch assembly (122) includes providing a pulse to a circuit (200) that include one or more electromagnetic latch assemblies. The circuit (200) includes coils (199) of the electromagnetic latch assemblies. Each coil is inductively coupled with an armature (131) that is mechanically coupled to a latch pin (118). The circuit (200) is pulsed and a DC current in the circuit (200) that results from the pulse is measured over a first interval to determine a primary response. The current in the circuit (200) over a second interval is measured to determine a reference response. A second pulse may be used to generate the current for the reference response. The primary response and the reference response are compared to provide diagnostic information relating to position or movement of one or more of the latch pins (118).