Abstract: An engine cooling system for increasing and controlling a wall temperature of a cylinder head is provided. The cooling system includes a radiator passage that passes through a radiator, a radiator-bypass passage that bypasses the radiator, a first fluid temperature sensor that acquires a fluid temperature of an engine coolant flowing through a bore passage for cooling a cylinder, a second fluid temperature sensor that acquires the fluid temperature of the engine coolant flowing through a head passage for cooling a cylinder head, a thermostat valve arranged in the radiator passage, a flow rate regulator valve arranged in the radiator-bypass passage, and an electronic control unit (ECU). While controlling the thermostat valve on the basis of a detection result of the first fluid temperature sensor, the ECU controls the flow rate regulator valve on the basis of a detection result of the second fluid temperature sensor.

Abstract: In response to a switching demand from an all-cylinder operation to a reduced-cylinder operation, the amount of air to be taken into each of cylinders 2A to 2D is made larger than the amount of air during the all-cylinder operation in a normal state. Preparatory control of changing the ignition timing of ignition device to a timing on the retard side with respect to the ignition timing during the all-cylinder operation in the normal state is executed. After termination of the preparatory control, the reduced-cylinder operation is started. During execution of the preparatory control, the valve closing timing of an exhaust valve 9 is changed to a timing on the advance side with respect to the valve closing timing thereof during the all-cylinder operation in the normal state so as to reduce the amount of internal EGR gas in at least a part of an operating range C.

Abstract: A variable cylinder engine is provided. The engine includes an engine body having a plurality of cylinders, a cooling mechanism for cooling the engine body by using a coolant, and a controller for controlling a temperature of the coolant and changing the number of active cylinders according to an operating state of the engine. The controller reduces the number of active cylinders in a reduced-cylinder operating range set within a partial engine load range, and expands the reduced-cylinder operating range to a higher engine load side as the coolant temperature becomes lower.

Abstract: In response to a switching demand from an all-cylinder operation to a reduced-cylinder operation, the amount of air to be taken into each of cylinders 2A to 2D is made larger than the amount of air during the ail-cylinder operation in a normal state. Preparatory control of changing the ignition timing of ignition device to a timing on the retard side with respect to the ignition timing during the all-cylinder operation in the normal state is executed. After termination of the preparatory control, the reduced-cylinder operation is started. During execution of the preparatory control, the valve closing timing of an exhaust valve 9 is changed to a timing on the advance side with respect to the valve closing timing thereof during the all-cylinder operation in the normal state so as to reduce the amount of internal EGR gas in at least a part of an operating range C.

Abstract: A variable cylinder engine is provided. The engine includes an engine body having a plurality of cylinders, a cooling mechanism for cooling the engine body, and a controller for controlling the cooling mechanism and changing a number of active cylinders according to an operating state of the engine. The controller reduces the number of active cylinders in a reduced-cylinder operating range set within a partial engine load range, and in a first reduced-cylinder range set within a high load part of the reduced-cylinder operating range, the controller improves a cooling performance of the cooling mechanism compared with that in a second reduced-cylinder range set within a low load part of the reduced-cylinder operating range.

Abstract: A control device of a spark-ignition gasoline engine is provided. The control device includes a controller for operating the engine body by controlling at least a fuel injection valve, an ignition plug, and a fuel pressure variable mechanism. Depending on the engine load range, the controller sets the combustion mode to a compression-ignition mode or a spark-ignition mode. In each mode, the controller also controls the fuel pressure, and the timing of fuel injection and ignition. The controller may also performs external EGR control in each mode.

Abstract: A variable cylinder engine is provided. The engine includes an engine body having a plurality of cylinders, a cooling mechanism for cooling the engine body, and a controller for controlling the cooling mechanism and changing a number of active cylinders according to an operating state of the engine. The controller reduces the number of active cylinders in a reduced-cylinder operating range set within a partial engine load range, and in a first reduced-cylinder range set within a high load part of the reduced-cylinder operating range, the controller improves a cooling performance of the cooling mechanism compared with that in a second reduced-cylinder range set within a low load part of the reduced-cylinder operating range.

Abstract: A variable cylinder engine is provided. The engine includes an engine body having a plurality of cylinders, a cooling mechanism for cooling the engine body by using a coolant, and a controller for controlling a temperature of the coolant and changing the number of active cylinders according to an operating state of the engine. The controller reduces the number of active cylinders in a reduced-cylinder operating range set within a partial engine load range, and expands the reduced-cylinder operating range to a higher engine load side as the coolant temperature becomes lower.

Abstract: The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller operates a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection mechanism to perform at least a fuel injection into the cylinder by a cylinder internal injection valve at a timing during a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing during the retard period and after the fuel injection.

Abstract: The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller operates a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection mechanism to perform at least a fuel injection into the cylinder by a cylinder internal injection valve at a timing during a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing during the retard period and after the fuel injection.

Abstract: A control device of a spark-ignition gasoline engine is provided. The control device includes a controller for operating the engine body by controlling at least a fuel injection valve, an ignition plug, and a fuel pressure variable mechanism. Depending on the engine load range, the controller sets the combustion mode to a compression-ignition mode or a spark-ignition mode. In each mode, the controller also controls the fuel pressure, and the timing of fuel injection and ignition. The controller may also performs external EGR control in each mode.

Abstract: A ceramic honeycomb filter comprising pluralities of ceramic honeycomb structures each having large numbers of flow paths partitioned by cell walls, which are bonded in the direction of the flow paths, predetermined flow paths being sealed by plugs, plugs formed at one end of at least one honeycomb structure being bonded to at least part of plugs formed at one end of a honeycomb structure adjacent to the end of this honeycomb structure.

Abstract: A ceramic honeycomb filter comprising pluralities of porous ceramic honeycomb structures 1A, 1B each having large numbers of flow paths 41, 42, 43 partitioned by cell walls 30, which are connected to each other in a flow path direction, desired flow paths being sealed such that an exhaust gas passes through pores of the cell walls 30, the cell walls 31 of at least one honeycomb structure 1A being connected by plugs 50 to the cell walls 32 of a honeycomb structure 1B adjacent thereto with a gap 54 in the flow path direction, and a catalyst being carried by at least part of the cell walls 30 and/or the plugs 50, 52, an exhaust gas-cleaning apparatus comprising the ceramic honeycomb filter and a fuel-adding means disposed upstream thereof, and an exhaust gas-cleaning method using the ceramic honeycomb filter.