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为了应对柴油机日益增长的需求,并力求在提高扭矩性能的同时实现节能,开发了1款新型高效率2.8L直列4缸柴油机。该发动机以1种创新的燃烧概念为基础,通过减少冷却损失,使发动机效率得到了提高。通过限制缸内气流及改善燃烧室隔热,减少了冷却损失。为了避免限制气流对排放产生影响,开发了1种能够通过优化缸内燃油分布来提高缸内气体利用率的新燃烧室形状。采用了1种能够根据气体温度改变壁面温度的新型隔热涂层来提高燃烧室的隔热性能,因而减少了冷却损失,并避免了进气加热的协调作用。为了采用这种燃烧概念,并同时提高动力性能,必须着重调整进排气道的高流量特性。通过采用具有独立功能的进气道、优化进气门的直径和布置、以及提高进排气系统的总体效率实现了这种调整。由于优化气道形状需要更大的设计自由度,因此开发了1种具有较高密封性能的新型气缸盖衬垫,这种缸径为92mm的气缸盖衬垫仅采用4个缸盖螺栓。由于整台发动机都贯彻这种燃烧概念,并结合各种减小摩擦的技术,该发动机的CO2排放比原有机型的减少了约15%,最高热效率约达到44%。
In response to the growing demand for diesel engines and aiming to save energy while improving torque performance, a new high-efficiency 2.8L inline 4-cylinder diesel engine has been developed. The engine is based on an innovative combustion concept that improves engine efficiency by reducing cooling losses. By limiting the cylinder air flow and improve the combustion chamber insulation, reducing the cooling loss. In order to avoid limiting the effects of airflow on emissions, a new combustion chamber shape was developed that can improve in-cylinder gas utilization by optimizing in-cylinder fuel distribution. A new insulation coating that changes the temperature of the wall based on the temperature of the gas is used to improve the thermal insulation of the combustion chamber, thus reducing cooling losses and avoiding the synergic effect of intake air heating. In order to adopt this concept of combustion and at the same time to improve the dynamic performance, it is necessary to focus on adjusting the high-flow characteristics of the intake and exhaust passage. This adjustment is achieved by the use of independently functioning inlets, optimizing the diameter and arrangement of the intake valves, and increasing the overall efficiency of the intake and exhaust system. Because of the greater design freedom required to optimize the shape of the airway, a new type of cylinder head gasket with high sealing performance has been developed. This type of cylinder head gasket with 92mm cylinder diameter uses only 4 cylinder head bolts. As the entire engine implements this concept of combustion and incorporates various friction-reducing technologies, the engine has a CO2 emission reduction of about 15% and a maximum thermal efficiency of about 44% over the previous model.