Based On The Engine Valve Actuator Valve Timing Optimization

Variable valve technology is an effective method for engine's energy-saving and environmental protection. Proper valve timing can improve the gas exchange process, increase combustion efficiency and reduce the pollutant emissions. Independent, continuously variable and real-time adjustable valve movement can be achieved by using the Electromagnetic actuated valvetrain. Optimum valve timing at engine's different work conditions can be achieved by electronic control, and non-throttling load control can be realized by adjusting the intake valve closing angle. Electromagnetic actuated valvetrain can improve engine's performance at full load condition and fuel economy at part load condition obviously, and is the development direction of engine's valvetrain.An electromagnetic actuated valvetrain has been developed based on a moving coil electromagnetic linear actuator, and several prototypes have been manufactured. Based on the EMAV's performance test, this paper studied the valve timing optimization at different work conditions using engine's one-dimensional numerical simulation for the next engine test. The main contents include the following:Using the software of AVL BOOST, a gasoline engine's model was established and validated by the experimental data, and a satisfied calculation precision was achieved.The combination simulation and optimization platform was established with engine's numerical simulation and genetic algorithm as the optimizing method, which makes auto-optimization of engine's valve timing possible.With the target of engine power, valve timing at full load condition was optimized for the modes of variable intake valve and variable intake and exhaust valves. According to research, the EMAV can improve engine's low-end torque by above 13%.The load control method by adjusting intake valve closing angle was discussed. With the target of fuel economy, the valve timing at part load condition was optimized, then, at low and medium speed conditions, modes of single and double intake valves were roughly studied. According to research, engine's fuel economy at low and medium load conditions was improved obviously because of the reduction of pumping loss.