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介绍丰田公司开发的一种新型2.0L双顶置凸轮轴4气门直喷式汽油机。它运用了若干新技术,如涡流进气道通过可调的涡流控制阀产生优化的缸内涡流,具有凹坑燃烧室的活塞和高压燃油喷射系统在燃烧室内形成良好的燃空混合气。这些都有助于部分负荷时极稀薄分层燃烧混合气的形成和火焰传播。应用电控EGR和NO_X催化剂来降低NO_X排放。高负荷时在进气行程中通过直接喷油形成均匀混合气。通过电子节流阀控制系统,使分层进气和均质进气工况的输出扭矩过渡平稳。试验证明,安装这套系统的车辆成功地改善了燃油经济性,同时满足了排放要求。
Introduced a new Toyota developed 2.0L double overhead camshaft 4-valve direct injection gasoline engine. It utilizes several new technologies such as swirl inlets to create optimized in-cylinder vortices through adjustable eddy current control valves, pistons with pit combustion chambers and high pressure fuel injection systems to create a good fuel-air mixture in the combustion chamber. These contribute to the formation of extremely lean stratified combustion mixture and flame propagation at part load. Use of electrically controlled EGR and NO_X catalysts to reduce NO_X emissions. High load in the intake stroke by direct injection to form a homogeneous mixture. Through the electronic throttle control system, stratified intake and homogeneous intake conditions of the output torque smooth transition. Tests have shown that vehicles equipped with this system have successfully improved fuel economy while meeting emission requirements.