A method for estimating wear of at least one component of an internal combustion engine includes receiving sensor information and fuel commands indicative of an amount of fuel supplied to at least one combustion chamber of the internal combustion engine and determining an incremental increase in an amount of wear of at least one component of the internal combustion engine based on at least the sensor information and the fuel commands. The method also includes determining an updated amount of wear based on the incremental increase in the amount of wear, and outputting a notification indicative of the updated amount of wear.

A method for diagnosing the valve timing of an internal combustion engine, a characteristic curve of an actual intake manifold pressure signal being ascertained as a function of a crankshaft signal, the characteristic curve of the actual intake manifold pressure signal being compared to a characteristic curve of a setpoint intake manifold pressure signal and a shift of the valve timing being diagnosed in the event of a specifiable deviation of the actual intake manifold pressure signal from the setpoint intake manifold pressure signal.

A method for estimating wear of at least one component of an internal combustion engine includes receiving sensor information and fuel commands indicative of an amount of fuel supplied to at least one combustion chamber of the internal combustion engine and determining an incremental increase in an amount of wear of at least one component of the internal combustion engine based on at least the sensor information and the fuel commands. The method also includes determining an updated amount of wear based on the incremental increase in the amount of wear, and outputting a notification indicative of the updated amount of wear.

Various embodiments include a method for checking a variable valve lift control of an internal combustion engine comprising: during operation of the internal combustion engine, detecting a rotational speed of the internal combustion engine; and measuring an intake pressure in the intake tract of the internal combustion engine corresponding to the detected rotational speed. The method further includes: defining a reference frequency dependent on the rotational speed of the internal combustion engine; defining a comparison frequency as a non-integral multiple of the reference frequency; determining amplitudes of oscillations of the intake pressure at the reference frequency and amplitudes of oscillations of the intake pressure at the comparison frequency; and evaluating a ratio of the determined amplitudes and the respective absolute values.

A rocker arm assembly that includes an electromagnetic latch assembly with a latch pin and an actuator operative to actuate the latch pin between a first position and a second position. The actuator includes an electromagnet powered through a coil circuit. The rocker arm assembly further includes a switch in a switch circuit. The coil circuit and the switch circuit are connected in parallel. Moving the latch pin between the first position and the second position opens and closes the switch. In an alternate embodiment, relative motion of two rocker arms opens and closes the switch. The rocker arm assembly allows OBD information to be obtained without making electrical connections to the rocker arm assembly other than ones provided to power the electromagnet.

Systems and methods for determining operation of a cylinder deactivating/reactivating device are disclosed. In one example, a direction of engine rotation is selected to maximize air flow through the engine while the engine is rotated without combusting air and fuel. Operation of one or more cylinder valve deactivating mechanisms is assessed while the engine is rotated without combusting air and fuel.

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 method of two-step variable valve lift (VVL) malfunction avoidance learning control may include: in a two-step VVL system which is operated with a main lift and a secondary lift, verifying, by an electronic control unit (ECU), an operation avoidance area based on locking of a lock pin of a cam follower ; performing VVL operation learning, in which a failure of occurrence of the second lift is determined on the basis of a locking failure of the cam follower due to an initially set value of the operation avoidance area; and reflecting the operation avoidance area to the two-step VVL system with a corrected set value which is obtained through the VVL operation learning.

A two-stroke internal combustion engine has an engine block having a cylinder block and a cylinder head. The cylinder block defines a cylinder, an exhaust passage, and an exhaust valve passage. The engine also has a piston, an exhaust valve actuator operatively connected to at least one of the cylinder block and the cylinder head, and a reciprocating exhaust valve disposed at least in part in the exhaust valve passage. The exhaust valve has a shaft operatively connected to a valve actuator, and a blade connected to the shaft. A channel is defined along a face of the blade. The channel and a wall of the exhaust valve passage together define at least in part a valve passage. The valve passage permits flow of exhaust gas along the face of the blade. A width of the valve passage is at least a third of a width of the blade.

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.