A valve timing adjustment device having a phase adjustment unit including an input rotator, a driving rotator that rotates in conjunction with a crankshaft, a driven rotator that rotates in conjunction with a camshaft that changes a relative rotation phase between the driving rotator and the driven rotator. A controller is configured to perform a startup phase control when operation of the internal combustion engine is started, the startup phase control including setting the relative rotation phase to a predetermined initial phase, and perform a startup preparation control during a period after the internal combustion engine is stopped and before the startup phase control is performed, the startup preparation control including changing the relative rotation phase.

An engine control system of a vehicle includes a cylinder control module configured to: determine a target sequence for at least activating and deactivating cylinders of an engine based on a torque request; and activate and deactivate the cylinders of the engine according to the target sequence. A values module is configured to determine, based on the target sequence, a plurality of coefficients and an offset value. An indicated mean effective pressure (IMEP) determination module is configured to determine an IMEP of a first cylinder based on: the plurality of coefficients; the offset value; and a plurality of engine speeds at a predetermined crankshaft positions, respectively.

A compression-ignition engine control system is provided, which includes an intake phase-variable mechanism and a controller. Within a first operating range and a second operating range on a higher engine load side, the controller controls the variable mechanism to form a gas-fuel ratio (G/F) lean environment in which an air-fuel ratio inside a cylinder is near a stoichiometric air-fuel ratio and burnt gas remains inside the cylinder, and controls a spark plug to spark-ignite mixture gas inside the cylinder to combust in a partial compression-ignition combustion. The controller controls the variable mechanism to retard the intake valve open timing on an advancing side of TDC of an exhaust stroke, as the engine load increases within the first range, and advance the intake valve close timing on a retarding side of TDC of intake stroke, as the engine load increases within the second range.

The present disclosure provides a valve timing adjustment apparatus for an internal combustion engine. The apparatus includes an anti-rotation mechanism for inhibiting a position change between a rotor and a housing by inhibiting or preventing relative rotation of the rotor to the housing. The anti-rotation mechanism includes: a plurality of locking grooves formed on the ratchet plate with different depths and connected to each other; and a locking pin member having an outer pin elastically disposed in a fitting hole formed in one of the vanes, and an inner pin elastically disposed inside the outer pin. In particular, the inner pin locks the rotor to the housing when the outer pin and the inner pin are sequentially fitted in the locking grooves by torque from the camshaft.

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 failure diagnosis apparatus according to the present disclosure is applied to a variable compression ratio mechanism that can switch the compression ratio of an internal combustion engine between at least a first compression ratio and a second compression ratio lower than the first compression ratio. When the variable compression ratio mechanism is controlled so as to set the compression ratio of the internal combustion engine to the second compression ratio, the failure diagnosis apparatus advances the ignition timing of one cylinder to a knock inducing ignition timing more advanced than the MBT that does not lead to the occurrence of knock if the actual compression ratio of that cylinder is the second compression ratio but leads to the occurrence of knock if the actual compression ratio of that cylinder is the first compression ratio and diagnoses failure of the variable compression ratio mechanism on the basis of whether knock occurs or not.

Various embodiments include a method for identifying valve stroke phase differences during operation comprising: measuring dynamic pressure oscillations in the air intake tract; generating a corresponding signal; acquiring a crankshaft phase angle; acquiring the phase position and the amplitude of a signal frequency of the oscillations based on the pressure oscillation using discrete Fourier transformation; acquiring a line of an equal phase position and of equal amplitude of the signal frequency reflecting the inlet and the outlet stroke phase difference using reference lines; acquiring a common intersection point of a line of equal phase position and a line of equal amplitude by projection into a common plane; and determining the stroke phase differences and from the common intersection point.

A control apparatus of a valve opening/closing timing control mechanism, configured by including driving side and driven side rotating bodies; a stopper unit; and an electric motor, includes: a phase controller controlling an electric motor to reduce, when a target phase is set, a deviation between the target phase and a current first actual phase and reducing power to be supplied to the electric motor as the deviation decreases; and a control target setting unit setting a first target phase displaced to a side of the first actual phase in an operation direction where the deviation is reduced when the target phase is set to a most retarded or most advanced angle phase, in which the phase controller executes a first phase control of reducing a deviation between the set first target phase and the current first actual phase.

Methods and systems are provided for controlling spark plug fouling in newly manufactured vehicles. In one example, an engine is operated with a first, more aggressive spark discharge schedule when in a pre-delivery state and transitioned to a second, less aggressive spark discharge schedule when in a post-delivery state. In each spark discharge schedule, a spark plug ignition coil is repeatedly discharged when the engine is off, such as when the engine is spinning down to rest on a shutdown event or before the engine is fueled on an engine restart event.

A control system of a compression-ignition engine which performs SPCCI combustion in which mixture gas is ignited with a spark plug to be partially combusted by SI combustion and the rest of mixture gas self-ignites to be combusted by CI combustion, is provided. When the engine is operated at least in a given first operating range, a controller of the device controls a variable intake mechanism so that an A/F lean environment where an air-fuel ratio in a cylinder becomes higher than a stoichiometric air-fuel ratio is formed, while causing the spark plug to perform spark ignition at a given timing so that the mixture gas combusts by SPCCI combustion, and controls so that, under the same engine load condition, an intake valve close timing is more retarded as the engine speed decreases, within a range where an amount of air inside the cylinder decreases by retarding the close timing.