Optimization Of Fuel Economy Of An Otto Cycle Engine Changed To Atkinson Cycle

With the increasing global energy crisis and environmental problems,the development of the automotive industry is facing new challenges.In recent years,under the development trend of energy saving and emission reduction,governments and automobile companies of various countries have been committed to the development of various new energy vehicles.However,after years of development,the technology of pure electric vehicles is still immature,which makes it unable to meet the urgent needs of the market in the short term,so that hybrid vehicles have become an inevitable trend in the current development of automobiles.Compared with the traditional Otto cycle engine,the Atkinson cycle engine can obtain better fuel economy,so it has been favored by the market and has been widely used in hybrid vehicles.This article takes a Otto cycle engine as the research object,according to the performance development needs of the engine,adopts a combination of numerical simulation calculation and test verification research method,to redesign the traditional Otto cycle engine.Using GT-POWER and ISIGHT for joint simulation optimization,an optimized solution to improve the fuel economy of the engine was proposed,and a bench calibration test was performed on the modified engine,which significantly improved the fuel economy of the engine and greatly shortened the development cycle.An improved reference idea is proposed for the change of engine working cycle and the improvement of fuel economy,which has certain academic reference value and practical guiding significance.The main research contents of this article are as follows:(1)Using the one-dimensional engine performance simulation software GT-Power,a performance simulation model of the original Otto cycle engine was built,and the original machine external characteristics test results were used for calibration to ensure the accuracy of the simulation model used to guide engineering practice.(2)Based on the original Otto cycle engine,combined with the engine working cycle theory,a technical method developed from Otto cycle to Atkinson cycle was proposed.The specific measures are: through reasonable optimization of the compression ratio,cam profile and valve phase,the Atkinson cycle of the engine is realized with minor changes.(3)The improved parameters are imported into the calibrated original Otto cycle engine performance simulation model,and the influence of the main parameters such as air-fuel ratio,ignition advance angle,intake retard angle,and exhaust advance angle on the engine performance is explored to determine the parameters of each parameter.Reasonably optimize the scope.(4)In order to avoid the blindness of engine bench calibration,GT-Power and Isight are used for joint simulation optimization,and the genetic algorithm is used to optimize the fuel economy of the engine,so as to determine the fuel economy optimization plan for the subsequent engine platform.Frame calibration provides guidance.(5)With the optimization plan as the guide,the engine bench calibration test was carried out.Bench calibration results show that the minimum fuel consumption of the engine has been reduced from 240g/(k W·h)to 230g/(k W·h).At the same time,the range of low fuel consumption operating conditions has also been significantly increased,which has significantly improved the fuel economy of the engine and reached Development purpose.Therefore,the optimization method and optimization plan are real and effective,and can be used to guide engineering practice.