Simulation And Experimental Research On Piston Secondary Motion Of158F Gaslion Engine

The noise of internal combustion engine can be divided into mechanical noise,combustion noise and aerodynamic noise according to the generation mechanism.Piston slap force not only is the main excitation source of internal combustion enginevibration, but also is a major factor in the production of mechanical noise. Pistonslapping in the cylinder directly causes friction wear of the piston and cylinder, when itis serious, it will lead to cylinder liner cavitation and generate a series of faults such asoil-leakage, gas leakage and water leakage, which influence the normal operation of theengine. Actual piston slap force is caused by the secondary motion of the piston, thepiston within the cylinder of the secondary motion to become an important researchtopic of scholars both at home and abroad.In this paper, use158F engine as the research object, it is equipped with twodifferent pistons, use their finite element model to calculate the respective radialstiffness matrix and thermal deformation data in Ansys software, as the boundaryconditions of secondary motion of the piston; Through experiments on specificconditions obtained the respective cylinder pressure curve and the cylinder wallvibration acceleration, cylinder pressure curve as the power input to AVL-EXCITE.Then building the model which includes piston, cylinder, piston pin, piston rings andconnecting rod in the multi-body dynamics software AVL-EXCITE, inputting engineoriented parameters and working condition, calculating the piston slapping.By calculating the secondary motion of the piston radial displacement, velocity,acceleration and rotation Angle, angular velocity and angular acceleration of the radialmotion of the piston in the cylinder and the piston rotation around pin shaft to make ageneral conclusion and have a deep understanding of secondary motion of the piston.Followed by calculating its under different rotational speed in full load, and at the samespeed under different load conditions of the second-order movement, studied theinfluence during running speed and the throttle opening on the piston slap force, we cansee with the increase of the rotational speed and throttle opening, under differentconditions of axial piston scraping force and radial tapping force the change trend isconsistent, and with the increase of the rotational speed and throttle opening, axialscraping force and radial tapping force have been increased. Throughout the cycle,occurs near the piston runs to near TDC a relative maximum striking force and maximum scraping force, while at high speed the piston in the process of running fromtop dead center to lower dead center, there will be a very significant volatility, whichmeans that the engine is running at high speed when the piston in the cylinder have tinyhorizontal swing, the main cause of this problem is the runtime of a piston reciprocatinginertial force is larger and the influence of cylinder clearance.Finally, according to the evaluation indicator such as radial displacement and axialscraping force and radial tapping force to evaluate A\B two different types lines ofpiston. and with the experimental measured vibration acceleration curve matchinganalyzed; Simulation data consistent with the experimental data to validate thecorrectness of the model, and the simulation and experiment show that performance ofpiston type B is better; From piston structure itself and the influential factors of thesecond-order piston movement system is analyzed, and selected focus two factorseccentric pins of piston and cylinder clearance for better performance of the B-typepiston optimized.