A method is provided for operating an internal combustion piston engine, including introducing air into a cylinder of the engine, compressing the air in a first compression stroke of the cylinder, providing fuel into the cylinder for a first combustion, with a portion of the oxygen in the compressed air as oxidant, in a first power stroke succeeding the first compression stroke, to produce residues including oxygen, compressing the residues in a second compression stroke succeeding the first power stroke, and providing, after the first combustion, fuel into the cylinder for a second combustion, with at least a portion of the oxygen of the residues as oxidant, in a second power stroke succeeding the second compression stroke, wherein the first compression stroke is repealed immediately after the second power stroke, and the introduction of air into the cylinder is done at the end of the second power stroke and/or at the beginning of the first compression stroke.

A control device and a control method for variable valve timing mechanism according to the present invention obtains a first measurement of a rotational phase based on a rotational angle of the motor, obtains a second measurement of the rotational phase based on a relative relationship between a rotational angle of the crankshaft and a rotational angle of the camshaft, calibrates the first measurement based on the second measurement, obtains a derivative term proportional to a rate of change in a deviation between the first measurement and a target value, reduces change in derivative term when calibrating the first measurement based on the second measurement, and controls the motor based on a manipulated variable including the derivative term.

A driving-side rotating body that rotates synchronously with a crankshaft of an internal combustion engine, a driven-side rotating body that is allowed to rotate relative to the driven-side rotating body and that rotates integrally with a camshaft that opens and closes an intake valve, and a phase adjustment mechanism for setting a relative rotation phase of the driving-side rotating body and the driven-side rotating body using a driving force of an electric motor are included. The phase adjustment mechanism is configured to be able to execute retarding control for setting the relative rotation phase to the retarding side until reaching a phase in which the internal combustion engine cannot be started and autonomous running is not possible even if fuel injection and ignition are performed in the internal combustion engine.

Provided is an internal combustion engine control device capable of maintaining an activation temperature of a catalyst while suppressing deterioration of an exhaust gas in a hybrid engine. To this end, the internal combustion engine control device of the present invention controls an internal combustion engine in an engine for a hybrid vehicle. The internal combustion engine has a catalyst that purifies the harmful substances in the exhaust gas and a catalyst temperature detection unit that detects the temperature of the catalyst. Then, when the temperature of the catalyst detected by the catalyst temperature detection unit does not reach a predetermined temperature, the internal combustion engine control device performs a catalyst temperature rise control for increasing the temperature of the catalyst and performs motoring.

A method for calculating the mass of an overlap gaseous flow (M.sub.OVL), wherein the exhaust pressure is higher than the intake pressure, or in the case of scavenging (SCAV), wherein the intake pressure is higher than the exhaust pressure. The overlap gaseous flow (M.sub.OVL) is the flow which flows, in overlap conditions, through the intake valve and the exhaust valve of a cylinder of an internal combustion engine. At least one intake valve is driven so as to vary the lift (H) of the intake valve in controlled manner. The overlap condition is a condition in which the intake valve and the exhaust valve are both at least partially open. The method comprises calculating the mass of the gaseous flow (M.sub.OVL) which flows through the intake valve and the exhaust valve on the basis of the relation:

M.sub.OVL=PERM*β(P/P.sub.0,n)*P.sub.0/P.sub.0_REF*(T.sub.0_REF/T.sub.0).sup.1/2/n.

Presented are multi-pulse fuel injection systems for monitoring engine fuel injectors for missed pulses, methods for making/using such systems, and vehicles equipped with such systems. A method of operating a fuel injection system includes an engine controller determining if the system's injectors are operating in a multi-pulse mode for injecting multiple fuel pulses per combustion cycle to an engine's cylinders and, if so, monitoring pulse signals transmitted to the injectors for injecting the multiple fuel pulses. For each combustion cycle for each injector, the controller flags a cylinder misfire if any one of the fuel pulses for that combustion cycle is missed. For each cylinder, the controller calculates a misfire ratio of a total number of cylinder misfires to a total number of combustion cycles; if one of these misfire ratios exceeds a calibrated misfire limit, the controller commands a resident subsystem to execute control operations to mitigate the misfires.

An engine is provided, which includes an engine body including a cylinder provided with intake and exhaust ports and intake and exhaust valves, intake and exhaust passages, a turbocharger including a turbine provided to the exhaust passage and a compressor provided to the intake passage, and a variable phase mechanism configured to change open/close timings of the intake valve while maintaining an open period of the intake valve at a 270° C.A or larger. A geometric compression ratio of the cylinder is 11:1 or higher. In a high-load range, the variable phase mechanism sets the intake valve close timing to be after an intake BDC and to make a ratio of a retarded amount of the intake closing to the geometric compression ratio be 4.58 or above and 6.67 or below, and sets the intake valve open timing to be before a close timing of the exhaust valve.

A control system for an engine including intake and exhaust valve phase variable devices and a control device is provided. At an engine temperature below a first determination temperature, the control is performed so that an exhaust valve close timing is at or retarded from the exhaust top dead center, an intake valve open timing is retarded from the exhaust valve close timing, and the fuel supply to the combustion chamber starts in an intake stroke on a retarding side of the exhaust valve close timing. At the engine temperature above the first determination temperature and below a second determination temperature, the control is performed so that a negative overlap with both the exhaust and intake valves closed during a period including the exhaust top dead center, or a positive overlap with both the exhaust and intake valves opened during a period including the exhaust top dead center, occurs.

In a control device for an internal combustion engine in which internal EGR and external EGR are conducted, an ideal in-cylinder gas amount and an ideal in-cylinder gas temperature in an ideal state in which neither of EGR gas recirculates into a cylinder are calculated (steps 1 and 2). A mixed gas amount of intake air and the external EGR gas present on a downstream side of a throttle valve is calculated, based on a rotation speed of the internal combustion engine and intake air pressure (step 21) to detect a mixed gas temperature. An actual in-cylinder gas temperature and amount and an EGR ratio are calculated, based on the ideal in-cylinder gas amount, the ideal in-cylinder gas temperature, the mixed gas amount, and the mixed gas temperature (steps 24, 4, and 5), and an internal combustion engine is controlled based on the EGR ratio.

An intake variable valve timing mechanism (VVT) that collectively changes an intake valve close timing as a close timing of a plurality of intake valves and a control device that controls an engine including a plurality of injectors and the intake VVT are provided. When a specified engine stop condition is satisfied, a fuel cut is performed to stop a fuel supply into a plurality of cylinders by the injector. After the fuel cut, the intake VVT is controlled such that a retarded amount of the intake valve close timing immediately before a stop of a stop-time compression stroke cylinder as a cylinder stopped in a compression stroke from intake bottom dead center is larger than a retarded amount of the intake valve close timing immediately before a stop of a stop-time expansion stroke cylinder as a cylinder stopped in an expansion stroke from the intake bottom dead center.