The effect of different coolants on emissions and fuel consumption of a diesel engine

Abstract

A diesel engine performance test system is set up based on the AVL framework, and an experimental investigation is conducted to evaluate the effects of three coolants on the diesel engine coolant outlet temperature, lubricating oil temperature, exhaust emissions and fuel consumption under real engine conditions. The results show that when the coolant circulating temperature is 80 °C, the exhaust temperature of the diesel engine using C-PG (anhydrous propylene glycol) coolant is the lowest, and the lubricating oil temperature is increased by 5 °C. Thus, when the coolant circulating temperature is 95 °C, the C-PG coolant is used. The outlet temperature and the lubricating oil temperature are similar to those of the other two coolants. The nitrogen oxides (NOx) emission of the diesel engine using C-PG coolant is slightly higher than that with the other two coolants, while the soot, carbon monoxide (CO) and hydrocarbon (HC) emissions are reduced. Finally, when the coolant circulating temperature is 95 °C, the fuel consumption using the C-PG coolant and L2 lubricating oil is reduced by 3.8%, compared with the C-EG (mixture of water and ethylene glycol) coolant and L1 lubricating oil.