The Thermal Research On Special Vehicle Driveline

The economic benefit of the heavy truck is gradually outstanding in the national economy and the heavy truck has been the main force in the highway transportation. The heavy truck which often drives in the mountainous area and the one having special missions has heavy thermal load in the vehicle's driveline. The working temperature region of the driveline is directly related to the vehicle driving stability, and affects the vehicle dynamic performance and fuel economy as well. The heat reject control mode is closly related to the parasitic loss of the power source.The thermal research on special vehicle driveline includes:1. The driveline dynamical model is built and the construction for the thermal management system is fixed. The detailed engine thermal management model is built. The heat source of the transmission is processed equivalently. And the engineering fluid mechanics (EFD) is adopted to set up the 3-D thermal model of the oil-to-air cooler.2. The driveline dynamical simulation provides the boundary conditions for the driveline thermal management system. The stability of the engine thermal management system and the performance characteristics of its components are considered based on the unidimensional simulation of the engine thermal management system. According to the 3-D fluid analysis, the heat-transfer characters of the oil cooler and the flow resistance of its air-side are obtained. The results of the simulation in transmission thermal management system are found out.3. The engine and transmission thermal management experiment are carried out respectively. The contents, methods of the two experiments are introduced, and the test data are processed and analyzed. The comparisions of the simulation result and test data verify the validity of the simulation models of the driveline thermal managenment system.4. The complete driveline thermal management model is built. On the basis of the same whole vehicle driving cycle, comparing to the traditional mechanical-drive system, the independent-drive system makes the working temperature of the heat source more stable. Meanwhile the parasitic power caused by the radiator fan is decreased markedly on the condition that the heat reject requirement of the heat source is satisfied.The main innovation points include:1. The heavy truck driveline thermal calculation platform is developed. The driveline thermal characteristics are obtained based on the parameters of the main driveline components and the whole vehicle. The radiator overall dimension, which ascertains underhood layout is calculated according to the design proposal of the thermal management system.2. The engineering fluid mechanics (EFD) is adopted to set up the 3-D thermal model of the oil-to-air cooler. The engry point is the radiator's most feasible fin unit which contains the most amount of the calculate cells that the server could process. The research on the thermal characteristic of the cooler is implemented while the computer resource is made full use of.3. The heavy vehicle driving cycle for the thermal management system is developed. The intercoupling of the driveline conponents in different working condition is considered in the driveline thermal management model. The control methed of the driveline thermal management system is studied for the aims of reducing the working temperature fluctuation of the heat source and the power consumption for the thermal management.