Water-cooling apparatus for engine

Abstract

A water-cooling apparatus for cooling an engine includes a radiator for cooling coolant, a first flow passage connected with the engine, a second flow passage branched from the first flow passage and connected with the radiator, a third flow passage whose one end is connected with the radiator and whose another end is connected with the first flow passage at a downstream from the branched point of the second flow passage, a regulating valve on the first flow passage for regulating a flow volume of the coolant in the radiator, and a pump on the first flow passage for circulating the coolant through the engine and/or the radiator. The regulating valve is configured to flows the coolant from the radiator to the first flow passage when it is opened. The apparatus has a simple circulation flow path, and thereby appropriate cooling can be done by regulating the flow volume.

1 . A water-cooling apparatus for an engine that cools an internal combustion engine by cooling water, the apparatus comprising:
 a radiator that cools the cooling water by heat-exchanging between the cooling water and air;   a first flow passage that flows the cooling water to the engine;   a second flow passage that is branched from the first flow passage and flows the cooling water to the radiator;   a third flow passage that flows the cooling water flowing from the radiator to the first flow passage at a downstream from a branched point of the second flow passage from the first flow passage;   a regulating valve that is disposed on the first flow passage and regulates a flow volume of the cooling water flowing through the radiator; and   a pump that is disposed on the first flow passage and circulates the cooling water through the engine and/or the radiator, wherein   the regulating valve is configured to flows the cooling water flowing from the radiator to the first flow passage when opened.   
     
     
         2 . The water-cooling apparatus for an engine according to  claim 1 , wherein,
 in a case where temperature of the cooling water that brings most appropriate combustion efficiency in a high-load state of the engine is defined as a first temperature,   when temperature of the cooling water in the engine is equal-to or higher-than the first temperature, the regulating valve closes a flow path through the second flow passage, the radiator and the third flow passage.   
     
     
         3 . The water-cooling apparatus for an engine according to  claim 1 , wherein
 the pump is an electrical pump operable independently from operations of the engine.   
     
     
         4 . The water-cooling apparatus for an engine according to  claim 1 , wherein,
 in a case where temperature of the cooling water that brings most appropriate combustion efficiency in a high-load state of the engine is defined as a first temperature, and temperature of the cooling water that brings most appropriate combustion efficiency in a low-load state of the engine is defined as a second temperature higher than the first temperature,   when temperature of the cooling water in the engine is equal-to or higher-than the first temperature and a change of a throttle position for adjusting an intake air volume to the engine is small, the regulating valve regulates a flow volume of the cooling water to a flow path through the second flow passage the radiator and the third flow passage so that the temperature of the cooling water is regulated to be the second temperature.   
     
     
         5 . The water-cooling apparatus for an engine according to  claim 1 , wherein
 in a case where temperature of the cooling water that brings most appropriate combustion efficiency in a high-load state of the engine is defined as a first temperature,   when temperature of the cooling water in the engine is equal-to or higher-than the first temperature and a change of a throttle position for adjusting an intake air volume to the engine is large, the regulating valve increases a flow volume of the cooling water to a flow path through the second flow passage the radiator and the third flow passage.   
     
     
         6 . The water-cooling apparatus for an engine according to  claim 1 , wherein
 the engine is inclined with an exhaust side thereof faced downward.