Abstract: An internal combustion engine is provided, which includes a variable phase mechanism configured to change rotational phases of intake and exhaust camshafts so that a valve overlap is made. An intake cam lobe is formed such that an open period of the intake valve is 210° or larger and 330° or smaller of a crank angle. The exhaust cam lobe is formed such that, during the overlap period with the rotational phase of the intake camshaft advanced to the maximum and the rotational phase of the exhaust camshaft retarded to the maximum, an effective valve lift amount (Lift(CA)) of the exhaust valve which is a function of a crank angle from the open timing (CAIVO) of the intake valve to a middle timing (CAcenter) of the overlap period, an inner circumferential length (L_ex) of a valve seat, and a swept volume (V) per cylinder satisfy the following formula: 0 . 0 ? 1 ? 5 ? L_ex V × ? C ? A IVO C ? A c ? e ? n ? t ? e ? r ? ? Lif ? t ? ? ( CA ) ? d ? C ? A .

Abstract: An internal combustion engine is provided, which includes a variable phase mechanism configured to change rotational phases of intake and exhaust camshafts so that a valve overlap is made. An intake cam lobe is formed such that an open period of the intake valve is 210° or larger and 330° or smaller of a crank angle. The exhaust cam lobe is formed such that, during the overlap period with the rotational phase of the intake camshaft advanced to the maximum and the rotational phase of the exhaust camshaft retarded to the maximum, an effective valve lift amount (Lift(CA)) of the exhaust valve which is a function of a crank angle from the open timing (CAIVO) of the intake valve to a middle timing (CAcenter) of the overlap period, an inner circumferential length (L_ex) of a valve seat, and a swept volume (V) per cylinder satisfy the following formula: 0 . 0 ? 1 ? 5 ? L ? _ ? ex V × ? C ? A IVO C ? A c ? e ? n ? t ? e ? r ? Lift ? ( CA ) ? d ? C ? A .

Abstract: 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?2?22.926?+207.84+C?IVC??0.4234?2+22.926??167.84+C where C is a correction term according to an engine speed NE (rpm), C=3.3×10?10NE3?1.0×10?6NE2+7.0×10?4NE.

Abstract: Disclosed is a control device for a multi-cylinder engine having a combustion chamber (19) to which an intake port (16) and an exhaust port (17) are connected. The control device comprises: an intake-side variable valve operating mechanism (71) for controlling a lift timing of two intake valves (21a, 21b) of the intake port (16); an exhaust-side variable valve operating mechanism (72) for controlling a lift timing of an exhaust valve (22a); and an exhaust-side valve operating mechanism (73) for driving an exhaust valve (22b) at a fixed timing. The control device is operable, when executing cylinder deactivation in a low engine load and low engine speed operating range, to cause the exhaust-side variable valve operating mechanism (72) to open the exhaust valve (22a) during downward movement of a piston (14) in a cylinder (18) being subjected to the cylinder deactivation.

Abstract: A control device for engine comprising; a variable valve operating mechanism (72) which comprises a cam (72d) and a pressure chamber (72c) internally filled with engine oil; and a hydraulic valve (72b) associated with the pressure chamber (72c) and configured to be opened and closed to control the oil pressure to be applied to an intake valve (22). When the engine load falls within a given low engine load range, the valve opening timing of the intake valve (22) is increasingly retarded according to the engine load and as the engine load becomes higher, within a limit of a given timing, and, when the engine load is increased beyond the given low engine load range, the valve opening timing of the intake valve is fixed to the given timing.

Abstract: A PCM (100) selects one of a CI mode or an SI mode based on the operating conditions of the engine (1). In the CI mode, the engine (1) is operated by compression ignition combustion. In the SI mode, the engine (1) is operated by spark ignition combustion. if, while the engine (1) is being operated in the CI mode, a determination is made that an estimated value (Tc) of the catalyst temperature is lower than or equal to a warming start temperature (Ts), the PCM (100) further performs first warming control to assign four cylinders (18) as CI and SI cylinders, which perform the compression ignition combustion and the spark ignition combustion, respectively, such that the four cylinders (18) alternately perform the compression ignition combustion and the spark ignition combustion in accordance with the order of combustion of the cylinders.

Abstract: 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?2?22.926?+207.84+C?IVC??0.4234?2+22.926??167.84+C where C is a correction term according to an engine speed NE (rpm), C=3.3×10?10NE3?1.0×10?6NE2+7.0×10?4NE.

Abstract: Disclosed is a control device for a multi-cylinder engine having a combustion chamber (19) to which an intake port (16) and an exhaust port (17) are connected. The control device comprises: an intake-side variable valve operating mechanism (71) for controlling a lift timing of two intake valves (21a, 21b) of the intake port (16); an exhaust-side variable valve operating mechanism (72) for controlling a lift timing of an exhaust valve (22a); and an exhaust-side valve operating mechanism (73) for driving an exhaust valve (22b) at a fixed timing. The control device is operable, when executing cylinder deactivation in a low engine load and low engine speed operating range, to cause the exhaust-side variable valve operating mechanism (72) to open the exhaust valve (22a) during downward movement of a piston (14) in a cylinder (18) being subjected to the cylinder deactivation.

Abstract: A engine control device includes an variable exhaust valve mechanism 72 which varies an opening and closing timing of an exhaust valve 22, and a PCM 10 which controls the variable exhaust valve mechanism 72 such that the opening and closing timing of the exhaust valve 22 is varied, wherein the variable exhaust valve mechanism 72 is configured such that a lift amount of the exhaust valve 22 becomes smaller as a retarded degree of the valve opening timing increases, and the PCM 10 is configured to set a maximum retarded valve opening timing in an exhaust stroke based on the lift amount at an exhaust top dead center, and to control the variable exhaust valve mechanism 72 so as to open the exhaust valve 22 in advance of the maximum retarded valve opening timing.

Abstract: A PCM (100) selects one of a CI mode or an SI mode based on the operating conditions of the engine (1). In the CI mode, the engine (1) is operated by compression ignition combustion. In the SI mode, the engine (1) is operated by spark ignition combustion. if, while the engine (1) is being operated in the CI mode, a determination is made that an estimated value (Tc) of the catalyst temperature is lower than or equal to a warming start temperature (Ts), the PCM (100) further performs first warming control to assign four cylinders (18) as CI and SI cylinders, which perform the compression ignition combustion and the spark ignition combustion, respectively, such that the four cylinders (18) alternately perform the compression ignition combustion and the spark ignition combustion in accordance with the order of combustion of the cylinders.

Abstract: When a specific condition requiring a rise in exhaust gas temperature is satisfied, a required fuel amount to be injected from an injector (21) is injected in a split manner, such that the fuel injection is divided to: a main injection (X1) to be initiated a given period before a compression top dead center; an auxiliary injection (X2) to be initiated after initiation of auto-ignited combustion of an air-fuel mixture consisting of air and the fuel injected by the main injection (X1) and before an assumed peak timing (Pk?) of a heat release rate (RH) from the combustion based on the main injection (X1); and a post injection (X3) to be initiated after the assumed peak timing (Pk?) and before completion of combustion based on the main injection (X1) and the auxiliary injection (X2). This makes it possible to raise an exhaust gas temperature while sufficiently ensuring auto-ignitability and fuel economy performance.

Abstract: Disclosed is an engine control system which is designed to allow homogeneous-charge compression ignition combustion to be performed in an HCCI region (R) defined as an engine operating region including at least a partial-load range of an engine. In a low load zone (R1) of the HCCI region (R), a lift amount of an intake valve (11) is set to a first predetermined value, and an exhaust valve (12) is allowed to start being opened during an intake stroke at a given timing later than an opening timing of the intake valve (11). Further, in the medium load zone of the HCCI region, the lift amount of the intake valve (11) is gradually increased up to a second predetermined value greater than the first predetermined value, along with an increase in an engine load. The engine control system is capable of adequately controlling an amount of burned gas to be introduced into a cylinder, depending on the engine load to allow the HCCI combustion to be adequately performed in a wider engine load range.

Abstract: Disclosed is an engine control system which is designed to allow homogeneous-charge compression ignition combustion to be performed in an HCCI region (R) defined as an engine operating region including at least a partial-load range of an engine. In a low load zone (R1) of the HCCI region (R), a lift amount of an intake valve (11) is set to a first predetermined value, and an exhaust valve (12) is allowed to start being opened during an intake stroke at a given timing later than an opening timing of the intake valve (11). Further, in the medium load zone of the HCCI region, the lift amount of the intake valve (11) is gradually increased up to a second predetermined value greater than the first predetermined value, along with an increase in an engine load. The engine control system is capable of adequately controlling an amount of burned gas to be introduced into a cylinder, depending on the engine load to allow the HCCI combustion to be adequately performed in a wider engine load range.

Abstract: When a specific condition requiring a rise in exhaust gas temperature is satisfied, a required fuel amount to be injected from an injector (21) is injected in a split manner, such that the fuel injection is divided to: a main injection (X1) to be initiated a given period before a compression top dead center; an auxiliary injection (X2) to be initiated after initiation of auto-ignited combustion of an air-fuel mixture consisting of air and the fuel injected by the main injection (X1) and before an assumed peak timing (Pk?) of a heat release rate (RH) from the combustion based on the main injection (X1); and a post injection (X3) to be initiated after the assumed peak timing (Pk?) and before completion of combustion based on the main injection (X1) and the auxiliary injection (X2). This makes it possible to raise an exhaust gas temperature while sufficiently ensuring auto-ignitability and fuel economy performance.

Abstract: A combustion control apparatus is configured for a direct-injection spark-ignition internal combustion engine. The combustion control apparatus selects an extremely retarded combustion mode while the internal combustion engine is in a predetermined operating state. In the extremely retarded combustion mode, the combustion control apparatus sets ignition timing to be after compression top dead center, and sets fuel injection timing to be before the ignition timing and after compression top dead center. The combustion control apparatus inhibits the extremely retarded combustion mode while an exhaust purifier of the internal combustion engine is in a predetermined cold state.

Abstract: There is provided a spark ignited internal combustion engine having a geometric compression ratio of 13.0 or greater. The engine comprises combustion chambers having a cylinder stroke volume of 0.3 liter or greater, with the spark plug in the chamber ceiling having its spark point in the combustion chamber, and a cavity being formed on the top surface of the piston. At least part of the cavity defines a spherical surface that a hypothetical sphere having its center at the spark point contacts when the piston is at top dead center. The cavity is formed so that V2/V1?0.31, where V1 is top-dead-center combustion chamber volume, and V2 is the volume of the part of the hypothetical sphere not interfering with the combustion chamber floor or ceiling at top dead center. The flame thus spreads with less interference, shortening combustion duration and reducing fuel consumption.

Abstract: There is provided a spark ignited internal combustion engine having a geometric compression ratio of 13.0 or greater. The engine comprises combustion chambers having a cylinder stroke volume of 0.3 liter or greater, with the spark plug in the chamber ceiling having its spark point in the combustion chamber, and a cavity being formed on the top surface of the piston. At least part of the cavity defines a spherical surface that a hypothetical sphere having its center at the spark point contacts when the piston is at top dead center. The cavity is formed so that V2/V1?0.31, where V1 is top-dead-center combustion chamber volume, and V2 is the volume of the part of the hypothetical sphere not interfering with the combustion chamber floor or ceiling at top dead center. The flame thus spreads with less interference, shortening combustion duration and reducing fuel consumption.

Abstract: In control apparatus and method for an inner cylinder spark ignited internal combustion engine having a fuel injection valve configured to directly inject fuel into an inside of an engine cylinder and a spark plug, a super retard combustion is executed to set an ignition timing after a compression stroke top dead center and to inject fuel before the ignition timing and after the compression stroke top dead center during a predetermined engine driving condition and at least part of fuel is injected before the compression stroke top dead center to decrease a fuel injection quantity after the compression stroke top dead center during an interval which is immediately after an engine start and in which a pressure of fuel is relatively low.

Abstract: A combustion control apparatus configured to operate a direct-injection spark-ignition internal combustion engine in a top dead center injection operating mode. In the top dead center injection operating mode, a fuel injection start timing is set to be before compression top dead center, a fuel injection end timing is set to be after compression top dead center, and an ignition timing is set to be after compression top dead center. The combustion control apparatus is configured to promote incylinder fuel spray penetration.

Abstract: In control apparatus and method for an inner cylinder spark ignited internal combustion engine having a fuel injection valve configured to directly inject fuel into an inside of an engine cylinder and a spark plug, a super retard combustion is executed to set an ignition timing after a compression stroke top dead center and to inject fuel before the ignition timing and after the compression stroke top dead center during a predetermined engine driving condition and at least part of fuel is injected before the compression stroke top dead center to decrease a fuel injection quantity after the compression stroke top dead center during an interval which is immediately after an engine start and in which a pressure of fuel is relatively low.