ИССЛЕДОВАНИЕ ТЕПЛООБМЕНА АГРЕГАТОВ ТРАНСМИССИИ И ДВИГАТЕЛЯ ГРУЗОВОГО АВТОМОБИЛЯ

Abstract

A significant share of goods in agriculture are transported by road at low ambient temperatures. Changing the properties of oils in these conditions significantly reduces the efficiency of the machines and requires additional measures for the thermal preparation of the units. (Research purpose) The research purpose is identifying heat flows between the engine and the transmission units of a truck and their effect on the thermal mode of the middle and rear axles. (Materials and methods) We performed experimental studies on a KamAZ 65115 car. Convective heat flows and heat transfer through thermal conductivity in the "engine-transmission units" system, as well as their effect on the thermal mode of transmission gearboxes, were studied. (Results and discussion) The effect of the engine on the thermal mode of the gearbox was established: the oil temperature rise was five degrees; the oil temperature stabilization time was 70-74 minutes. The effect of the engine on the thermal mode of the middle and rear axles was not revealed. It was shown that the main heat flows causing the gearbox to heat up are the air flows washing the block and crankcase of the engine. An increase in the air flow velocity to 25 meters per second leads to a decrease in temperature near the engine block by 2.5 percent to 278 kelvin, and near the crankcase by 3 percent to 253 kelvin. (Conclusions) Engine temperature has a significant effect only on the temperature of the gearbox. At air speeds above 10 meters per second, stabilization of transmission temperature is observed. Heat flows that cause additional heating of the gearbox are formed on the side surfaces of the cylinder block and the engine oil sump.