基于声能叠加的TGDI汽油机噪声分离方法

Noise Separation Method of TGDI Engine Based on Sound Energy Superposition

汽油涡轮增压缸内直喷(TGDI)汽油机燃烧噪声显著、声源耦合性强,精准分离噪声源对控制汽油机整机噪声至关重要.利用声能叠加理论建立TGDI汽油机定点声源能量叠加方程,依据多工况下辐射噪声与缸内压力、转矩的线性叠加关系,获得缸内压力与燃烧噪声声功率的结构传递系数H、转矩与随负荷变化机械噪声声功率的传递系数G.利用H计算获得燃烧噪声,利用G确定随负荷变化机械噪声和不随负荷变化机械噪声,通过倒拖试验验证噪声分离结果的准确性.依据噪声源分离结果探究各噪声源声压级及贡献度变化规律,为TGDI汽油机噪声源控制提供参考.

Turbocharged gasoline direct injection(TGDI)engines have significant combustion noise and strong coupling of sound sources.Accurate separation of the noise sources is essential to control the noise of the gasoline engines.The sound energy superposition theory was used to establish fixed-point sound source energy superposition equations for a TGDI engine.According to the linear superposition relationship between radiation noise,cylinder pressure and engine torque under multi-point operating conditions,the structural transmission coefficient H of cylinder pressure and combustion noise sound power,and the transmission coefficient G of torque and load-dependent mechanical noise sound power were obtained.H was used to calculate the combustion noise,and G was used to determine both the load-dependent mechanical noise and the load-independent mechanical noise.The accuracy of the noise separation results was finally verified by the towing test.According to the results of noise source separation,the sound pressure level and contribution degree of each noise source were analyzed,the research results provide a reference for the noise source control of TGDI engines.