Development Of Mini Vehicle Engine And Vehicle Heat Balance Test System

Increasing engine thermal efficiency and improving its performance have been pursued by the people for long. To make the engine work in the best condition, neither hot nor cold, must ensure its proper working temperature range. The cooling capacity of cooling system directly affects the engine operating temperature. So a good cooling system should ensure that the engine can work in the appropriate range in all conditions.According to the GB/T 18297-2001 Performance test code for road vehicle engines, GB/T 12534-90 Motor vehicles-General rules of road test method and GB/T 12542-2009 Thermal balance capacity on-road test method for motor vehicles, this article works out test program of the engine heat balance and vehicle thermal balance and analyzes the result. Engine heat balance test is conducted in engine performance bench including the dynamometer bench, exhaust gas analyzer and coolant circulating systems. Coolant achieves the cooling and temperature control through coolant circulating systems. Control the temperature of coolant at the right temperature range. Measure the physical quantity when engine work in the ideal condition. According to the calculation methods of parts heat, gain the heat distribution of engine in different conditions, include the effective power, heat taken away by coolant, heat taken away by exhaust and lost heat. Heat taken away by exhaust always is the difficulty of measure and calculation. Obtain volume ratio of each gas in exhaust by exhaust gas analyzer. Get the average specific heat capacity of exhaust combined with the relationship between heat capacity of each gas and temperature. Gain the total weight of exhaust by mass conversation, and then calculate out heat taken away by exhaust. According to the experimental data, gain the change law of parts of heat with the engine working condition's change in load characteristics and external characteristics, and analyze their change law linked with operational principle of engine. Obtain the dynamic relationship between speed, torque and heat taken by coolant by linear regression of binary. Then can work out heat taken by coolant in different working conditions. Provide data support for selection and design of radiator.The purpose of vehicle heat balance teat is that measure the operating parameters in extreme and routine conditions by road test. This article also highlights the development of vehicle thermal balance test system, include selection and installation of sensors and design of data acquisition system. Check the cooling capacity of vehicle's existing cooling system through exit coolant temperature of engine, allowable ambient temperature and temperature rising curve. Calculate the actual amount of cooling air through the radiator and the theory needs cooling air flow, and do match comparison. Research the way of improving the vehicle's cooling capacity by improving the utilization of the wind and air intake factor.