Design Optimization of Cooling System for a Tractor Engine Using Ethylene Glycol-Water Base Fluid

An experimental study was conducted to evaluate the thermal performance of a tractor diesel engine cooling system using a 50:50 ethylene glycol (EG)–water coolant. The objective was to characterize how cooling parameters vary with engine operating conditions. A tractor engine was coupled to a dynamometer and cooled by a radiator in a closed loop. Temperatures, flow rate, engine speed, exhaust losses, and brake power were measured. Results show that the coolant temperature drop across the radiator remained nearly constant (~3°C) over 1000–2000 rpm. Exhaust heat loss rose nearly linearly with speed (from ≈13 kW at 1000 rpm to ≈32 kW at 2000 rpm), indicating more waste heat at higher loads. Brake thermal efficiency peaked at about 37.5% around 1400 rpm, then declined at higher speeds, consistent with increased heat and friction losses. Flywheel power reached ≈41 kW at 1800 rpm and plateaued. Increasing coolant flow rate elevated the convective heat-transfer coefficient and heat removal rate. In summary, the cooling system-maintained engine temperature effectively, with best performance in the midRPM range. The 50:50 EG–water mixture provided adequate heat rejection, but its ~20% lower heat capacity requires slightly higher flow (≈15–20%) than pure water.