Optimization design of downsize engine structure based on dynamic knock excitation

The small size of the city vehicle gasoline engine is the key point of the current energy saving and emission reduction. The application of multi stage turbocharger technology has become a research hotspot, which leads to a higher compression ratio, the average effective pressure in the combustion chamber is further increased, and the engine knock phenomenon is frequent. In this paper, based on the measurement of the pressure in the cylinder of the gas suction, the influence of the knock excitation on the strength of the piston is studied, pressure of the detonation is taken as the dynamic excitation of the piston, and the stress distribution under the dynamic excitation is studied. Then simulate the actual working conditions of the engine by changing the maximum value of cylinder pressure.