An internal combustion engine system includes an internal combustion engine and a control device. A difference of an intake valve closing timing with respect to a compression top dead center is referred to as a first crank angle difference; a difference of an exhaust valve closing timing with respect to an exhaust top dead center is referred to as a second crank angle difference; and a difference between the first crank angle difference and the second crank angle difference is referred to as an intake/exhaust closing timing difference. The control device is configured to execute: a fuel cut processing; and a valve driving processing to control at least one of the intake valve closing timing and the exhaust valve closing timing such that the intake/exhaust closing timing difference becomes smaller during a fuel cut operation than during a non-fuel cut operation.

Provided is a method for changing gear ratio in a gearbox comprising: receiving a signal to change the gear ratio; calculating braking torque that the engine should provide to reduce the rotational speed of the engine to a target rotational speed; phase-shifting a second camshaft in relation to the crankshaft, to a state where the exhaust valve is controlled to be opened during the expansion stroke and closed during the exhaust stroke; disconnecting the engine from the driving wheel; opening and closing the exhaust valve with a decompression device in a transition area between an exhaust stroke and an inlet stroke and also between a compression stroke and an expansion stroke, when the piston is at a top dead center in the cylinder to achieve engine braking through compression in the cylinders during the exhaust stroke and the compression stroke, and f) shifting a gear in the gearbox.

A control device has a VVT (variable valve timing) mechanism which changes opening or closing timing of at least one of an intake valve and an exhaust valve, and includes: a processor; a sensor for detecting atmospheric pressure; and a sensor for detecting the amount of air flowing through an intake air flow path. The processor calculates a charging efficiency based on the detected amount of air, calculates a volumetric efficiency from the detected amount of air and the detected atmospheric pressure, calculates the charging efficiency valve opening timing of the intake valve based on the charging efficiency, calculates the volumetric efficiency valve opening timing of the intake valve based on the volumetric efficiency, and sets the valve opening timing(s) of at least one of the intake valve and the exhaust valve based on one of the charging efficiency valve opening timing and the volumetric efficiency valve opening timing.

A control apparatus for a vehicle that includes an engine including an intake valve and an exhaust valve includes an electric generator, a lock up clutch, and a valve timing controller. The valve timing controller is able to control valve timing of the intake valve or the exhaust valve, or both, to a low efficiency region and a high efficiency region. The valve timing controller controls the valve timing to the high efficiency region on the condition that the electric generator performs regenerative power-generation on decelerated travel of the vehicle. The valve timing controller controls the valve timing to the low efficiency region on the condition that the lock up clutch is switched from an engaged state to a disengaged state, with the valve timing having been controlled to the high efficiency region on the decelerated travel.

A method, computer program product and apparatus for the pilot control of a mixture preparation for an internal combustion engine are disclosed, which include determining a configuration of the internal combustion engine. The configuration is determined by a combination of discrete positions of a plurality of actuators which influence at least one operating parameter of the internal combustion engine. The method, computer program product and apparatus additionally determine a constant adaptation component of the mixture preparation which is fed back by an exhaust gas probe of the internal combustion engine, and store the constant adaptation component and the associated configuration in memory. The pilot control of the mixture preparation is performed with the constant adaptation component when the internal combustion engine is operated in the same configuration.

A method of implementing control logic of a compression-ignition engine is provided. A controller outputs a signal to a injector and a variable valve operating mechanism so that a gas-fuel ratio (G/F) becomes leaner than a stoichiometric air fuel ratio, and an air-fuel ratio (A/F) becomes equal to or richer than the stoichiometric air fuel ratio, and to an ignition plug so that unburnt mixture gas combusts by self-ignition after the ignition plug ignites mixture gas inside a combustion chamber. The method includes steps of determining a geometric compression ratio and determining the control logic defining an intake valve close timing IVC. IVC (deg.aBDC) is determined so that the following expression is satisfied: if the geometric compression ratio is 10<17,
0.4234.sup.222.926+207.84+CIVC0.4234.sup.2+22.926167.84+C
where C is a correction term according to an engine speed NE (rpm),
C=3.310.sup.10NE.sup.31.010.sup.6NE.sup.2+7.010.sup.4NE.

An internal combustion engine includes combustion chambers, each having a controllable intake valve controlling an intake port, a controllable exhaust valve controlling an exhaust port, a piston, and a fuel injector. An intake manifold is connected to the intake port of each chamber. In catalytic converter warm-up mode, each chamber is driven in four-stroke operation including a 720 crank angle degrees cycle, and opens the intake port, starting to open in 90-180 CAD, and fully closes the intake port in 180-270 CAD, opens the exhaust port during the power stroke, starting in 405-495 CAD, opens the intake port during the exhaust stroke, starting in 610-690 CAD, and fully closes the exhaust port during the exhaust stroke in 630-710 CAD. Exhaust gas is forced into the intake manifold by the piston, mixing fuel and exhaust in the intake manifold, and fully closes the intake port in 700 to 720+20 CAD.

Methods and systems are described for controlling fuel injection in an engine equipped with a dual injector system including a port injector and a direct injector. A ratio of port injected fuel to direct injected fuel is adjusted based at least on intake valve temperature. The proportion of fuel port injected into a cylinder is increased as the intake valve temperature for the given cylinder increases to improve fuel vaporization in the intake port.

A method of implementing control logic of a compression-ignition engine is provided. A control part of the engine performs a calculation according to the control logic corresponding to an engine operating state in response to a measurement of a measurement part, controls a fuel injection part, a variable valve operating mechanism, an ignition part and a supercharger so that a G/F becomes leaner than a stoichiometric air fuel ratio and a A/F becomes equal to or richer than the stoichiometric air fuel ratio, while causing the supercharger to boost, and controls the ignition part so that unburnt mixture gas combusts by self-ignition after the ignition. The method includes determining a supercharging pressure P, and determining control logic defining a close timing IVC of an intake valve. When determining the control logic, the close timing IVC (deg.aBDC) is determined so that the supercharging pressure P (kPa) satisfies the following expression: P8.010.sup.11IVC.sup.61.010.sup.8IVC.sup.5+3.010.sup.7IVC.sup.44.010.sup.6IVC.sup.3+0.0068IVC.sup.20.3209IVC+116.63.

A storage device stores mapping data and association data. The mapping data defines a mapping that outputs an estimated value of the temperature of a catalyst using a warm-up operation amount variable and the previous value of the estimated value as an input. The association data associates the integrated value of an intake air amount of an internal combustion engine from the startup of the engine and the temperature of the catalyst. The execution device repeatedly calculates the estimated value based on the output of the mapping. When the correspondence relationship between the integrated value and the estimated value is different from the correspondence relationship between the integrated value and the temperature of the catalyst in the association data, the warm-up process is determined to have an anomaly.