直喷式柴油机瞬态工况燃烧噪声控制研究

Study on the Combustion Noise Control of DI-Diesel Engines under Transient Conditions

开展多缸柴油机瞬态工况燃烧噪声的控制研究。分别在四缸自然吸气发动机、增压发动机、引入EGR发动机和高压共轨发动机上开展了不同负荷工况下的瞬态与稳态工况的燃烧噪声测试分析,开展了增压、EGR和喷射策略对燃烧噪声控制研究。增压对瞬态工况的燃烧噪声有一定的抑制作用,增压对恒转速增转矩瞬态工况燃烧噪声的控制效果要好于对恒转矩增转速工况。瞬态工况引入适当的EGR有助于燃烧噪声的降低,EGR控制瞬态工况燃烧噪声的关键是能够实时对EGR率进行调节。相对于稳态工况,瞬态工况下应取较大的预喷量和与主预喷间隔,并得到试验的验证。

This paper focuses on the control of the combustion noise under transient conditions of muhi cylinder diesel engines. Tests, analysis and control methods of combustion noise under transient and steady-state conditions under different loads are made on four-cyhnder naturally aspirated engines, turbocharged engines, EGR-introduced engines, and high pressure common rail engines. Turbocharging is useful for reducing combustion noise in transient conditions. Turbocharging has better effect on the control over combustion noise in transient conditions with constant engine speed and increasing torque than in conditions with constant torque and increasing engine speed. Introduction of appropriate EGR is helpful for the reduction of combustion noise in transient conditions. The key to the control of combustion noise with EGR under transient conditions is that whether real-time adjustment of EGR rate can be made to realize the optimization of EGR rates for different transient conditions. Compared with steady-state conditions, larger pilot injected quantity and longer interval between main injection and pilot injection should be selected for transient conditions and verification is obtained in tests.