Influence of the coolant temperature on emission of toxic compound and engine work parameters

The selected results of investigations of the cooling system for the combustion engine working with higher temperature of the cooling liquid were presented. The temperature of this liquid were increased to the temperature of boiling water, as a basic compound of the cooling liquid. This system was designed for the four cylinder diesel engine 4CT90 with indirect fuel injection system. Investigation was realized on the dynamometer stand equipped with standard measure devices (measures: speed, torque, temperatures, flows) and exhaust gas analyzers. The speed and torque engine characteristics were determined. The over pressure inside cooling system was limited up to 0.07 MPa regarding lower pressure structural integrity of the standard units of this system. Intensity of the cooling, protective against too higher pressure, were changed by switching small and full liquid circulation, and one or two fans of the cooler. temperature inside cooling system was increased up to 110 centigrade. Results ofincreasing of the cooler temperature were lower frictions of unburned products of combustion process (CO and HC) in the exhaust gas (up to 50%) in low torque and low engine speed. This is area when catalytic reactor does not work because too low is exhaust gas temperature. It wasfound that engine economy was increased to 7% in maocimum load and high engine speed.