Design And Development Of The Engine Coolant Temperature Control System On Test Bench

The engine cooling mode running on the test bench is different from the vehicle driving on road which used cooling fan and radiator.At present,the engine bench test coolant temperature control system using proportional valve + heat exchanger technology can achieve stable temperature control accuracy of ±2?,to meet the national standards and enterprise standards.The engine coolant temperature control system which meets quick thermal shock test needs to be equipped with independent heating and cooling device to realize the rapid cooling and heating load transformation.But the temperature control response time and control precision need to be improved.And It is difficult to communicate and share with different brands of dynamometer and temperature control equipment.In this paper,research and analysis based on the technology of domestic and foreign coolant temperature control system,combined with the enterprise requirements of bench test,design and development the coolant temperature control system to meet the constant temperature and rapid thermal shock test requirements,high control precision,good transient response,low cost.Designed to significantly reduce the cost of equipment development and use,enhance the domestic engine test equipment development capabilities and levels.According to the step by step design and development method,first of all,the overall design of the temperature control system is conventional to constant temperature control and rapid thermal shock temperature control.Then,the temperature control system of heat capacity analysis,heat exchanger,proportional valve,temperature controller,water pump,solenoid valve etc.are designed and selected.The hardware and software of the coolant temperature control system is also design and the development of communication,drive and control functions.Finally,the temperature control system is tested and verified by the engine bench.The bench test results show that through the PID parameter adjustment,proportional valve zero check and control,solenoid valve delay,tank with auxiliary heating device,liquid infusion tank technology and optimization of control strategy improve the temperature control accuracy.Finally realizes the development goals.Constant temperature control accuracy of0.8 degrees centigrade,control accuracy increased by 60% relative to the traditional equipment.Using two sets of temperature control system of parallel + solenoid valve delay control,the coolant heating process is shortened to 40 seconds,the temperature rise rate reaches 2.1 DEG /S,variable working temperature control accuracy of less than ±1.5?,achieve enterprise rapid thermal shock test.In addition,compared with the current rapid thermal shock equipment,under the premise of ensuring the temperature rise rate,the energy storage capacity of the thermal storage tank and the auxiliary heating device can be greatly reduced.