The high-efficiency dedicated hybrid engine (DHE) has led to increasingly complex challenges in engine thermal management. On one hand, the high compression ratio of up to 16:1 makes the engine more susceptible to knocking, necessitating meticulous thermal management to mitigate the potential sensitivity to metal temperature. On the other hand, extensive use of external cooled exhaust gas recirculation (EGR) helps reduce knocking and improve thermal efficiency, but it also raises temperature levels and requires additional cooling measures.For the 1.5L DHE developed by SAIC Motor, a split cooling structure was employed in the engine cooling system design, with the cylinder head water jacket and cylinder block water jacket arranged in parallel and equipped with different coolant outlets. By utilizing a dual thermostat to control flow, this design allows for adjustable flow distribution, providing effective cooling to the cylinder head while reducing cooling to the cylinder block. The block thermostat can close the flow of the block water jacket before the water temperature reaches the opening temperature, enabling quick warming of the cylinder block.Furthermore, an electric water pump was employed as an ideal solution for the DHE, eliminating the need for a front-end drive system. This helps reduce parasitic losses due to accessories and improve overall efficiency. As the primary driving source for coolant in the entire cooling system, the electronic water pump plays a crucial role in the overall thermal management system. Specialized control strategies and software have been developed to optimize its performance.This paper presents the development of thermal management, including cooling system design and simulations, as well as test development. It also elaborates on the control strategy development for the electric water pump, which meets the requirements of the engine and vehicle under various environmental and operating conditions.

为了深入研究活塞冷却喷射的油束运动发展规律及不同活塞冷却方式对传热的影响,对比研究了3种活塞冷却方案.首先,在稳定的流场环境里对油束进行了验证,保证了后续瞬态强气流条件下喷射计算的准确度.通过曲轴箱内的仿真计算,得到了活塞冷却喷射图像、内冷油道与活塞底面的平均传热系数分布、活塞的温度分布.针对模型A(内冷油道强制冷却+活塞冷却喷射)活塞进行了温度测量,对比了各测点的试验温度与仿真温度,并研究了各方案的活塞温度场.结果表明:该算法可以比较准确地模拟活塞冷却喷射现象,准确反映机油在内冷油道和活塞底部的流动和传热规律,活塞温度场分布比较合理,监测点温度与试验比较吻合,最大偏差仅为5.24％.

In the past, the problem of vehicle booming noise is exposed in the real vehicle stage, when most of the related parts are locked, so it is difficult to change any design. Only by adding damper and other patching measures can be taken to solve the problem. In this paper, the optimization research of booming noise is introduced, by means of CAE and DFSS tools in the early design stage of the vehicle. Through the analysis of transfer path, it is found that the path that contributes the most noise comes from the path “power train-tie bar mount-sub frame-vehicle body”. The CAE model is established to predict the vehicle interior noise. The sensitivity of parameters of the tie bar path is studied in detail and optimized design is carried out by using DFSS tool. The simulation results show that the maximum second order booming noise of the vehicle is reduced by 3 dB after optimization. The analysis method and results are validated by test.

为满足消费者需求和日益严格的法规要求,上汽乘用车公司通过采用缸内中置直喷、高效涡轮增压、进排气可变正时技术、集成式排气歧管等一系列先进节能减排技术开发了全新1.5 L四缸汽油发动机,搭载荣威名爵多款车型,实现了低油耗、低排放、低噪音、高性能、高可靠性等设计目标,并在此基础上进行了技术升级开发.结果显示:通过燃烧系统优化及Miller循环应用,在保持250 Nm最大扭矩的同时,提升发动机热效率,降低整车新欧州行驶循环(NEDC)油耗6.5％;通过燃烧系统、增压器和冷却水套等一系列设计优化,最大扭矩提升至275 Nm,低速增压响应提升25％;通过喷雾油束优化和35 MPa高压喷油系统应用,发动机颗粒排放大幅降低,使得整车在全球轻型汽车测试循环(WLTC)工况下不带汽油机颗粒捕集器(GPF)达到国6b颗粒排放限值要求.

The present paper describes a CAE analysis approach to evaluate the design of exhaust manifold of a turbo charged gasoline engine. It allows design engineers to identify structural weakness at the early stage or to find the root cause of exhaust manifold failures. A transient none-linear finite element method is used to calculate the plastic deformation and thermal mechanical behaviors of the exhaust manifold assembly during thermal shock cycles, which include rated speed full load, rated speed motored and idle speed conditions. A transient heat transfer simulation is performed to provide thermal boundary conditions for the nonlinear stress/strain analysis. The finite element model includes a part of cylinder head, exhaust manifold, gaskets, turbo charger housing, catalytic converter, brackets, bolts and nuts. The results show that plastic deformation is the main cause of manifold cracking and the manifold flange distortion causes the exhaust leakage. The simulation results indicate that predicted crack locations and leak area are in agreement with that from the engine durability test. Based on the baseline calculation results, local geometric modifications are made, which include changed shape of the inlet flange, changed location of anchor bolt hole and removing the internal baffle. For the modified design of the exhaust manifold, the cumulated equivalent plastic strain and the gasket sealing pressure at the end of third cycle meet the guideline limits. The modified exhaust manifold successfully passed all tests. Finally, general design recommendations of exhaust manifold are summarized in the paper.