Abstract: An engine cooling system has an engine water jacket, a coolant circulation passage connecting a water jacket outlet to a water jacket inlet and a radiator disposed in the coolant circulation passage. A thermostat valve selectively closes and opens the coolant circulation passage leading to the radiator. A bypass passage extends from between the water jacket outlet and the thermostat valve to an outlet side of the radiator. A bridge passage connects a portion of the bypass passage to a portion of the coolant circulation passage located downstream of the radiator and upstream of where the bypass passage merges therewith. A resistance generating section is located downstream of the bridge passage connection to the coolant circulation passage and upstream of the bypass passage connection to the coolant circulation passage. The bridge passage has an oil heat exchanger to exchange heat between the cooling medium and transmission oil passing therethrough.

Abstract: An engine cooling system has an engine water jacket, a coolant circulation passage connecting a water jacket outlet to a water jacket inlet and a radiator disposed in the coolant circulation passage. A thermostat valve selectively closes and opens the coolant circulation passage leading to the radiator. A bypass passage extends from between the water jacket outlet and the thermostat valve to an outlet side of the radiator. A bridge passage connects a portion of the bypass passage to a portion of the coolant circulation passage located downstream of the radiator and upstream of where the bypass passage merges therewith. A resistance generating section is located downstream of the bridge passage connection to the coolant circulation passage and upstream of the bypass passage connection to the coolant circulation passage. The bridge passage has an oil heat exchanger to exchange heat between the cooling medium and transmission oil passing therethrough.

Abstract: In a diesel engine which conducts exhaust gas recirculation and low temperature pre-mixed combustion at a low compression ratio, an ambient temperature at initiation of combustion which is determined by a compression ratio and an intake gas temperature or engine load is determined to be in a low temperature region which is lower than a first target temperature T1 which supports pre-mixed combustion or not. When the ambient temperature at initiation of combustion is determined to be in a region that is lower than a first target temperature T1, a temperature increase control device is operated which increases the temperature of the operational gases in the cylinder so that the temperature at initiation of combustion exceeds a first target temperature. The main fuel injection timing is placed in the range of 5.degree.-20.degree. of the combustion top dead center so that the main combustion temperature is above a fixed value.

Abstract: A fuel injection timing of a fuel injector (22) of a direct injection diesel engine is retarded to compression top dead center or even later. All of the required fuel injection amount is injected by the fuel injector (22) in an ignition delay period. The oxygen concentration in the combustion chamber (14) is decreased by exhaust gas recirculation. A swirl is set up in the combustion chamber (14) by a variable swirl generator (31). The compression ratio of the engine is preferably set to 15 or less, the vertical gas velocity in the combustion chamber is reduced by adopting a shallow piston cavity, and the cylinder internal maximum pressure is suppressed to 12 MPa or less.

Abstract: An exhaust gas purifying device which is provided with catalytic converter and a fuel injector which are disposed upstream of a particulate matter trap. The fuel injection injects fuel to the catalytic converter to rise exhaust gas temperature by its oxidation reaction heat when the exhaust gas temperature is slightly lower than a predetermined regeneration temperature. Further, a closable bypass passage is communicated with the passage between the catalytic converter and the trap and functions to allow to bypass exhaust gases in accordance with the trap condition and the exhaust gas temperature.