关键词: 发动机；高压油泵挺柱；敲击异响；噪声分析

Abstract: The turbocharged engine produces a knocking sound at idle when the high-pressure oil pump is under high pressure. The article aims to identify the root cause of the knocking sound and quickly resolve complaints in mass production. By analyzing the working principle of the highpressure oil pump and comparing measurements of relevant components such as the rocker arm, camshaft, and cover, it is ultimately determined that the source of the knocking sound comes from the rocker arm of the high-pressure oil pump. Through comparative measurements of key dimensions related to the rocker arm of the high-pressure oil pump, it is found that the unreasonable design requirements for verticality are the fundamental cause of the knocking sound. Using noise analysis equipment to evaluate the rocker arms of the high-pressure oil pump with different verticality requirements both subjectively and objectively, new design requirements for the verticality of the rocker arm are established, guiding suppliers to optimize their processes to meet these requirements, effectively eliminating the knocking sound.

Key words: engine; high pressure fuel pump tappet; knock with a strange sound; noise analysis