METHOD FOR DETECTING COMBUSTION NOISE AND MECHANICAL NOISE IN ENGINE

摘要

PURPOSE: A method for detecting combustion noise and mechanical noise of engine is provided to accurately and reliably detect combustion noise and mechanical noise of the engine. CONSTITUTION: A method comprises four steps. The first step(S200) is to measure engine noise level(SP) and cylinder pressure level(CP) of an engine classified by operational condition of the engine more than fixed times. The second step(S210,S220,S230) is to mark the engine noise level and the cylinder pressure level on a graph with cylinder pressure level as X-axis and engine noise level as Y-axis as a point and to calculate a linear function approximately represents the graph. The third step(S240) is to derivate mechanical noise(MN) of the engine from Y-intercept of the linear function and to derive structural attenuation of the engine from gradient of the linear function. The fourth step is to derive combustion noise(CN) of the engine from difference between the cylinder pressure on basic spark advance of the engine and the structural attenuation.