An internal combustion engine comprises a crankshaft, at least one camshaft adjustable electromechanically by an actuating gearing, an engine control unit, and a camshaft control unit for controlling an actuating motor which operates the actuating gearing. The engine control unit is linked to a device for detecting the angular position of the crankshaft, and the camshaft control unit is linked to the engine control unit. A device for detecting a reference position of the camshaft and a device for detecting the angular position of the shaft of the actuating motor are provided as sole mechanisms for detecting the angular position of the camshaft. The camshaft control unit is designed to determine the phase angle of the camshaft in relation to the crankshaft on the basis of the information items provided by said devices in combination with the detected angular position of the crankshaft and the transmission ratio of the actuating gearing.

A reciprocating exhaust valve for a two-stroke internal combustion engine has a shaft for connection to a valve actuator, the shaft defining a reciprocation axis of the valve, the reciprocation axis defining a longitudinal direction of the valve; and a blade having: a first end having an arcuate edge, a second end connected to the shaft, two side portions, and a central portion. The blade has a first end portion adjacent the first end that includes a part of the central portion and of each of the two side portions. A width of the central portion is greater than a width of each of the side portions. In the first end portion, a thickness of the part of each of the two side portions is greater than a thickness of the part of the central portion.

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.

An exhaust valve assembly for a two-stroke internal combustion engine has a housing adapted for connection to an engine block of the two-stroke internal combustion engine; an electric actuator having an electric motor, the electric motor being disposed in the housing; and at least one reciprocating exhaust valve operatively connected to the electric actuator. The at least one exhaust valve is linearly movable by the electric motor. A portion of the at least one exhaust valve is disposed in the housing.

An electromechanical camshaft phaser (3) comprises a setting gear (4) and an electric motor (5), which is controlled by means of an electric-motor control unit (6). Data concerning the operation of the electric motor (5) including position changes of its motor shaft are transferred via a data bus (8) from the electric-motor control unit (6) to an engine control unit (7) of the internal combustion engine (1) comprising the camshaft phaser (3). In addition, recurring time signals are transferred from the electric-motor control unit (6) to the engine control unit (7) via a separate line (9), by which harder real-time requirements are met than by the data bus (8). The time signals are used to generate a time difference signal in the engine control unit (7) by comparison with the data received by the engine control unit (7), which time difference signal is fed back to the electric-motor control unit (6) via the data bus (8) and is used there to synchronize the electric-motor control unit (6) with the engine control unit (7).

In a variable valve control device, a variable valve control system and a method for controlling a variable valve mechanism according to the present invention, An ECM (201) transmits a phase detection value (RA1) computed based on a crank angle signal (CRANK) and a cam angle signal (CAM) to a VTC control unit (202) via a communication network (211), and VTC control unit (202) computes a phase detection value (RA2) based on a motor angle signal (MAS), controls a variable valve timing mechanism (114) based on phase detection value (RA2) in the transient state of an internal combustion engine, and controls variable valve timing mechanism (114) based on phase detection value (RA1) in the steady state of the internal combustion engine.

Methods and systems for increasing exhaust gas temperatures of an engine are described. In one example, engine exhaust gas temperatures may be increased via deactivating cylinders and flowing exhaust gases through deactivated cylinder. Engine pumping losses may be reduced via the exhaust gases that flow through the deactivated cylinder so as to reduce engine fuel consumption while heating an exhaust gas after treatment device.

When an EDU determines that a motor is in a control unstable state where the motor cannot be controlled to a target rotation speed due to a drive voltage output duty value being smaller than a threshold value, the EDU performs a control point shifting operation to shift a control point between a first control point, which is in the control unstable state, and a second control point, which is a control stable state outside the control unstable state. Thus, even when the motor is in a stepping rotation state, it is possible to control the target rotation speed regardless of influence of a cogging torque, and appropriately control the cam phase of the intake camshaft to a target phase when the engine is stopped.

A method for adaptation of a detected camshaft position of a camshaft in an internal combustion engine with: Detection of an ACTUAL gas signal in a gas space that is associated with the camshaft and is associated with a detected camshaft position; Processing of the gas signal to produce an ACTUAL gas criterion; Modeling of multiple simulated gas criteria, each of which is associated with a target camshaft position; Determination of a simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of an ACTUAL camshaft position that corresponds to the simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of a camshaft position correction value from the difference between the ACTUAL camshaft position determined and the detected camshaft position; Determination of corrected camshaft positions by correcting the detected camshaft positions with the camshaft position correction value.

Various embodiments of the teachings herein include a method for controlling a cam using an ECU (electronic control unit) comprising: learning a holding region in which linearity is not ensured by increasing or decreasing a PWM signal while the cam maintains a holding state; based on the results of the learning, generating a final PWM signal; and transmitting the final PWM signal to an oil control valve. The final PWM signal comprises a sum of a minimum PWM signal for the cam to leave the holding region and a control PWM signal for the cam to reach a desired position.