Patent ID: 8695541
Filing Date: 2014-04-15
Classification: F01P

Abstract:
1. A cooling system for cooling an internal combustion engine by a flow of cooling water through the engine such that temperature of the engine in normal operation falls within a predetermined temperature range, wherein: at least a part of cooling water is used for a heat source for heating air blown toward an air-conditioning target space; and the engine includes a cylinder block, a block-side passage through which cooling water for cooling the cylinder block flows, a cylinder head, and a head-side passage through which cooling water for cooling the cylinder head flows, the cooling system comprising: a cooling water pressure-feeding unit configured to pressure-feed cooling water into the block-side passage and the head-side passage; a heating heat exchanger configured to exchange heat between cooling water flowing out from at least one of the block-side passage and the head-side passage, and the blown air; a radiating heat exchanger configured to exchange heat between cooling water flowing out of the block-side passage and the head-side passage, and outside air, so that cooling water radiates heat; a bypass passage that guides cooling water flowing out of the block-side passage and the head-side passage to bypass the heating heat exchanger and the radiating heat exchanger and to flow into a suction side of the cooling water pressure-feeding unit; and a flow regulating unit configured to regulate at least one of a block-side cooling water flow rate, which is a flow rate of cooling water flowing through the block-side passage, and a head-side cooling water flow rate, which is a flow rate of cooling water flowing through the head-side passage, wherein: at a time of warm-up of the engine, the flow regulating unit is configured to operate in a fuel efficiency priority mode in which: the flow regulating unit regulates the head-side cooling water flow rate to be equal to or smaller than a first upper limit, which is equal to or smaller than the head-side cooling water flow rate when the engine is in the normal operation; the flow regulating unit regulates the block-side cooling water flow rate to be equal to or smaller than a second upper limit, which is equal to or smaller than the first upper limit; and the flow regulating unit regulates the flow of cooling water such that cooling water flowing out of the block-side passage and the head-side passage flows mainly into the bypass passage; and when a heating request to heat the blown air by the heating heat exchanger is made at the time of warm-up of the engine, the flow regulating unit is configured to operate in a heating priority mode in which: the flow regulating unit regulates the head-side cooling water flow rate to be equal to or smaller than a third upper limit, which is equal to or smaller than the head-side cooling water flow rate when the engine is in the normal operation and higher than the first upper limit; the flow regulating unit regulates the block-side cooling water flow rate to be equal to or smaller than a fourth upper limit, which is equal to or smaller than the third upper limit; and the flow regulating unit regulates the flow of cooling water such that at least cooling water flowing out of the head-side passage flows into the heating heat exchanger.