An experimental study was carried out on a 3.8L turbocharged inter-cooled diesel engine to reveal the influences of intake pressure on the performance of the engine.In the experiments, the turbocharger and intercooler of the engine were removed and the intake and exhaust pressures of the engine were controlled directly by a self-made pressure control system.The experiment and simulation results show that when the exhaust back pressure is kept constant, the maximum cylinder pressure is in linear relationship with the intake pressure, and the maximum cylinder pressure rises by 4.8~7.0MPa every time the intake pressure increases by 100kPa.The corresponding crank angle of the maximum cylinder pressure has no clear relationship with the intake pressure.The mass flow rate is in linear relationship with the intake pressure, and the mass flow rate goes up by 13~37kg/h every time the intake pressure increases by 10kPa.The exhaust temperature has obvious linear relationship with the air to fuel ratio, and the exhaust temperature decreases by 4.2℃ every time the air to fuel ratio increases by 1.With the increase of the intake pressure, the ignition delay will be smaller, the combustion starts earlier, but the combustion duration has no clear change.The brake torque of the engine will increase by 0.8~2.5N·m every time the intake pressure increases by 10kPa.%在一台3.8L涡轮增压中冷4缸柴油机上通过试验和仿真研究了进气压力对柴油机燃烧和性能的影响.试验中拆除了原机增压器及中冷器,通过自制压力调节装置直接控制柴油机进、排气压力.试验及仿真结果表明:在排气压力维持不变的条件下,最高燃烧压力与进气压力具有明显的线性关系,进气压力每增加100kPa,最高燃烧压力增加约4.8MPa~7.0MPa;进气压力对最高燃烧压力相位的影响不明显;空气质量流量与进气压力具有明显的线性关系,进气压力每增加10kPa,空气质量流量增加约13~37kg/h;柴油机排气温度与空燃比具有明显的线性关系,空燃比每增加1,柴油机排气温度降低约4.2℃;随进气压力增加,柴油机缸内燃烧滞燃期缩短,燃烧始点提前,但进气压力对燃烧持续期没有明显影响;进气压力每增加10kPa,发动机转矩增加约0.8~2.5N·m.
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