集成排气歧管GDI发动机热平衡试验研究

Experimental Study on Thermal Balance of GDI Engine with Integrated Exhaust Manifold

本文中研究了不同的发动机台架热平衡试验方案和试验条件对集成排气歧管缸内直喷(GDI)汽油机热平衡性能试验结果的影响。结果表明:与传统发动机台架热平衡试验方法相比,基于实车散热器、冷却和进排气管路以及附件的台架热平衡试验方案,可降低管路变化造成的系统流动阻力增大、管路传热损失增加、冷却液流量不可控、发动机进出口冷却液温差过小等对热平衡试验不利的因素影响,试验结果更接近实车状态;中冷后进气温度、冷却液温度和开关冷却风机等对热平衡测试结果均有显著的影响;集成排气歧管式发动机的排气歧管内置在缸盖内导致发动机冷却水套的散热量明显增大,冷却系统也必须提供更大的冷却能力才能满足发动机的热平衡需要。

The effects of different engine bench test schemes and test conditions on thermal balance performance test resultsare studied experimentally on a GDI engine with integrated exhaust manifold.The test results show that compared with the traditional engine heat balance bench test method,the heat balance test scheme based on the real vehicle radiator,cooling system tubes,intake and exhaust pipes and accessories,can reduce the adverse impact on the heat balance test caused by pipes change,such as system flow resistance increase,heat transfer losses increase,uncontrollable coolant flow,too small temperature difference between the inlet and outlet of the engine,etc.,and the test results are closer to the real vehicle state.The inlet air temperatures after intercooling,coolant temperatures and on-offcooling fan have a significant impact on the results of heat balance test.The exhaust manifold of the engine with integrated exhaust manifold is built into the cylinder head,which results in a significant increase in heat dissipation of the engine cooling water jacket.As a result,the cooling system must also provide greater cooling capacity to meet the needs of the engine heat balance.