Design And Application Of Test System Of Rotary Engine

Compared with the traditional reciprocating piston engine,the rotary engine as a four-stroke engine has the advantages of simple structure,compact size,light weight,high power,and fuel flexibility.It can burn a variety of fuels including gasoline,diesel,natural gas and other fuels with different physical and chemical properties.In recent years,with the development of clean energy and hybrid electric vehicles,the rotary engine that can be used as a range extender for hybrid electric vehicles has once again become a research hotspot in the automotive industry.In order to improve the performance of the rotary engine,when the structure,manufacturing technology,type of fuel,electronic control system and other aspects of the rotary engine are changed,a lot of tests on the rotary engine are required in order to carry out theoretical research and demonstration or improved the overall performance evaluation.Due to the complexity of the rotary engine and the variability of the test contents,there are many types and numbers of parameters involved in the test process,so it is necessary to develop a stable,reliable and expandable rotary engine test system.In this paper,for a certain type of intake port injection gasoline rotary engine,a rotary engine test system composed of the existing test equipment,data acquisition card,and the graphical programming development platform Lab VIEW is developed based on virtual instrument technology.The main contents of this paper were as follows:(1)According to the requirements of rotary engine test,the function of the rotary engine test system is divided,and the structure and components of the test system are defined.The measurement principle of relevant test parameters is introduced in detail,and the range of parameter value is preliminarily estimated,based on which the selection of corresponding sensors for different types of test parameters.According to the function analysis of the test system,the function and design of the data acquisition card and the computer test interface are determined.(2)The test system is divided into two modules: hardware and software.In the hardware part,we use Freescale series single chip microcomputer as the core of the data acquisition card and design a series of circuits,including signal conditioning circuit according to the different sensor output signal,single chip microcontroller accessory circuit,power circuit and serial communication circuit.The software is divided into data acquisition procedures and communication procedures,the PC monitor interface design.The information collected by data acquisition card from signal sensors is sent to PC monitor interface by means of serial communication.The PC monitor program has completed functions such as serial port configuration,data processing,data display,and data storage.(3)The intake air flow rate of rotary engine is an important parameter that affects the development of electronic control system and the air-fuel ratio control of rotary engine using different fuels.The intake air flow rate measured by ordinary engine bench test can not completely cover every operating point in the engine speed and load range.In order to reduce the workload of measurement of rotary engine intake air flow rate,we constructed the intake system model of rotary engine based on the mean value engine model according to the characteristics of rotary engine intake system,and use the least square method to identify the undetermined parameters in the model.(4)The hardware and software of rotary engine test system are integrated.We carry on the bench tests on rotary engines to verify the function of the developed rotary engine test system.The MATLAB/ Simulink software is used to simulate the intake system model of rotary engine,and the validity of the model structure and the parameters to be determined are verified by comparing the simulation with the measured values of the bench test.