| Whether the selection of compression ratio and intake parameters of marine high-speed diesel engines is reasonable is very important to the performance of marine engines.Reasonable adjustment of the compression ratio has a great effect on the improvement of the overall performance.It can not only improve thermal efficiency,optimize power economy,but also increase combustion and other capacity,appropriately increase cylinder pressure and the highest pressure rise rate,and reduce cylinder heat at the same time,it also helps to improve the stability of internal combustion engine operation and maintain a better cold start capability;valve lift curve and valve timing(valve phase)are two very important intake parameters in the valve train.It can also determine the quality of the air exchange function of the ship,and further affect the overall performance of the ship.In order to further improve the power and economy of the marine high-speed diesel engine,and analyze the influence of the regular changes of related parameters on its working conditions,this paper uses the Z160 marine high-speed diesel engine of ZICHAI POWER CO.,LTD.still in the process of research and development as the prototype.Model theory and related parameters of the Z160 testing machine model were built and checked through the GT-POWER simulation software in GT-SUITE to build the Z160 marine high-speed diesel engine model.Subsequently,the simulation operation was carried out by means of variable experiments to analyze the effects of compression ratio,valve lift curve and valve phase on the performance of the Z160 marine high-speed diesel engine under different load conditions,and further studied the specific reasons for the related phenomena,and finally selected The relevant parameters that are most suitable for the common working conditions of ship machines are listed.Comparing the optimization results with the original simulator data,the research results show that the compression ratio of a supercharged marine high-speed diesel engine can be appropriately increased within a certain range,but when the compression ratio is too high,the mechanical load of the engine will increase and its performance and service life will be reduced..At the same time,the valve lift curve can be optimized by scaling the angle coefficient and the valve lift coefficient to effectively improve the air exchange capacity of the valve train,thereby greatly optimizing the performance of the internal combustion engine.Finally,according to the previous simulation results,the valve phase is optimized,and the best opening and closing time of the intake and exhaust valves is selected.Since the Z160 marine high-speed diesel engine often runs under high load and high speed,the main task of this optimization is also carried out under high load and high speed conditions,but since the actual opening and closing of the intake and exhaust valves are fixed parameters,it is difficult to improve The performance of the engine in the full operating range,so the performance of individual operating conditions under low load and low speed has slightly decreased,but because the decrease is very limited,it has little effect on the experimental results.At present,the Z160 marine high-speed diesel engine used in this article is in the research and development stage.The research content of this article has certain reference value for the improvement of its performance and the acceleration of the research and development progress.The final optimization results are as follows: Under 25% load operating conditions,the maximum optimization rates of torque,power,and fuel consumption are 8.5%,8.5%,and 7.9%respectively;under 50% load operating conditions,torque and power,the maximum optimization rates of fuel consumption are 6.9%,6.9%,6.4%;under 75% load operating conditions,the maximum optimization rates of torque,power,and fuel consumption are 6.2%,6.1%,and 5.7.%;Under 100% load operating conditions,the maximum optimization rates of torque,power,and fuel consumption are 7.9%,7.9%,and 7.3%,respectively. |
