| 摘要 |
PROBLEM TO BE SOLVED: To attain both of temperature rise acceleration of a cylinder head with water conduction restriction of cooling water and damage prevention of an EGR cooler, after cold start of an engine.SOLUTION: A cooling system of an engine includes: an EGR device; EGR valve control means that controls an EGR valve of the EGR device; a cooling water flow passage through which cooling water circulates, the cooling water flow passage containing a first flow passage passing through a cylinder head and a second flow passage branching from the first flow passage and passing through an EGR cooler of the EGR device; a cooling water pump that circulates cooling water in the cooling water flow passage; a flow rate control valve that controls a flow rate of cooling water in the second flow passage; temperature detection means that detects a temperature of cooling water in the first flow passage; and valve control means that controls opening of a flow rate control valve on the basis of a detection temperature. The valve control means, when the detection temperature is less than a temperature threshold and control of opening the EGR valve is not performed, has the zero opening of the flow rate control valve, and when the detection temperature is less than the temperature threshold and the control of opening the EGR valve is performed, opens the flow rate control valve.SELECTED DRAWING: Figure 9 |
