A method according to the invention for controlling an internal combustion engine having a camshaft whose phase with respect to a crankshaft can be adjusted by means of an electric adjustment device, and a control device comprises the steps S1 to S3, wherein in step S1 a stop request is output from the control device to the electric adjustment device. Subsequently, in step S2 a manipulated variable in the form of a pulse duty factor is output from the electric adjustment device, wherein the pulse duty factor counteracts a camshaft torque. In step S3, the direction of rotation of the camshaft is monitored, wherein in step S4, when a reversal of the direction of rotation of the camshaft is detected, an intensity level of this reversal of the direction of rotation is calculated by determining a rotational speed gradient. Furthermore, in a step S5 the pulse duty factor is corrected as a function of the rotational speed gradient in such a way that the influence of the reversal of the direction of rotation on the position of the camshaft is compensated.

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 control device for an engine of the invention executes an automatic stop control for stopping stop a rotation of a crank shaft when a predetermined automatic stop condition is satisfied. The device acquires a focused peak value of the engine speed appearing after a time when a rotation direction of the crank shaft first reverses while the automatic stop control has been executed, determines, based on the focused peak value, whether there will be an excessive peak value expected to depart from a predetermined permission range after the focused peak value appears, and executes a starter start control for driving the starter, restarting the fuel supply and igniting the fuel to restart an operation of the engine when a predetermined restart condition is satisfied, the engine speed is within the predetermined permission range and it has been determined that there will be no excessive peak value.

An engine control device includes an electronic control unit. The electronic control unit is configured to perform a spark discharge with an ignition plug for each cylinder by cutting off energization after elapse of a predetermined period from start of energization to an ignition coil for each cylinder of the engine, to stop the spark discharge caused by the ignition plug for each cylinder after supply of fuel to the engine is stopped when operation of the engine is stopped, and to control an ignition plug so as to stop the spark discharge caused by the ignition plug from a cylinder after a rotation speed of a crankshaft decreases gradually and the rotation speed of the crankshaft reaches a preset threshold value or less, after the stop of the supply of fuel to the engine.

Methods and systems are provided for diagnosing a positive crankcase valve during a vehicle key-off event. In one example, a method may include controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve, and indicating whether the positive crankcase valve is stuck open responsive to spinning the engine unfueled in a reverse direction, and indicating whether the positive crankcase valve is stuck closed responsive to spinning the engine fueled but without spark in a forward direction. In this way, functionality of a positive crankcase ventilation valve may be diagnosed effectively during key-off conditions, which may prevent or reduce engine complications arising from a stuck open or stuck closed positive crankcase valve.

Methods and systems are provided for diagnosing a positive crankcase valve during a vehicle key-off event. In one example, a method may include controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve, and indicating whether the positive crankcase valve is stuck open responsive to spinning the engine unfueled in a reverse direction, and indicating whether the positive crankcase valve is stuck closed responsive to spinning the engine fueled but without spark in a forward direction. In this way, functionality of a positive crankcase ventilation valve may be diagnosed effectively during key-off conditions, which may prevent or reduce engine complications arising from a stuck open or stuck closed positive crankcase valve.

Methods and systems are provided for purging condensate from a charge air cooler towards an intake air filter. In one example, a method may include operating a motor to rotate an engine in reverse and flowing air from the intake manifold to the atmosphere via the charge air cooler to purge condensate towards an intake air filter.

A toothed target rotationally fixed to a shaft of the engine includes a series of n real teeth, followed by m dummy teeth forming a reference zone. For each tooth k, the period of time separating the latter from the preceding tooth k1 is measured. A signal exhibits at least one transition in level in a portion of the signal corresponding to the passage of the reference zone. A first and a second product are calculated for at least some of the values of k; the ratio between these two products is calculated; and the direction of rotation of the engine is detected, in case of correspondence of the ratio with a first noteworthy value and with a second noteworthy value which are representative, respectively, of rotation in a normal direction and rotation in a reverse direction.

A vessel propulsion apparatus includes an engine that rotates a crankshaft in a forward rotation direction, a rotation speed detector that detects a rotation speed of the crankshaft, a propeller shaft coupled to a propeller, a shift switch that switches between a shift-in state and a neutral state, a shift state detector, an intake passage, a throttle valve, an intake pressure sensor, and a controller. The controller determines that the crankshaft is reversely rotating by an external force input from the propeller shaft when a predetermined reverse rotation recording condition is satisfied, and stores reverse rotation information. The reverse rotation recording condition includes a condition that an intake pressure after the shift switch switches from a neutral state to a shift-in state while the crankshaft rotates in the forward rotation direction is larger than a value equal to or higher than atmospheric pressure.

Disclosed is a method for processing a primary signal produced by a sensor detecting the rotation of a rotating target. The primary signal includes pulses having, for a given speed of rotation of the target, a first positive voltage level for rotation in a first determined direction or a second positive voltage level for the opposite direction. A first secondary signal is generated by comparing the primary signal to a first determined voltage threshold between the first and second voltages. A second secondary signal is generated by comparing the primary signal to a second determined voltage threshold between the second voltage level and zero. A determined delay is introduced in the second secondary signal. A determined time threshold is compared to the duration between an active edge of the second secondary signal and the last preceding active edge of the first secondary signal, indicating direction.