The Key Technology Of Automobile Fuel Consumption Test Based On Ultrasonic Technology

With the rapid growth of automobile ownership in China,the control of automobile fuel consumption is not only an energy problem,but also an environmental one.Carbon balance method is a major indirect way of testing the automobile fuel consumption which is of high precision,while the test equipment is expensive,bulky,unable to move,and the demanding of the test environment is high.The sample connection needs sealing and connecting to the exhaust pipe,so its application is limited.Direct test method tests the automobile fuel consumption through measuring fuel volume or quality within a certain distance or time,and the engine oil circuit needs to be taken apart in order to put in the fuel consumption meter.This method is inconvenient,time-consuming and with security risk,which affects the test precision.It is of great significance to research and develop automobile ultrasonic fuel consumption test instrument which can test automobile fuel consumption without disassembly.It helps solve the problem of domestic automobile fuel consumption test equipment,achieve energy conservation,emission reduction,and the development of automobile technology.Based on the automobile ultrasonic fuel consumption test theory,time difference method is more superior in testing fuel consumption.Therefore,we adopt ultrasonic time difference method to test automobile fuel consumption,construct the basic model of mathematical calculation of automobile ultrasonic fuel consumption test.we analyze main influencing factors of automobile ultrasonic fuel consumption test precision,put forward more precise research plan to test automobile fuel consumption.The adoption of the extended Kalman filtering method of calculating time difference overcomes the effect of zero test and related processing method of determining the starting point of ultrasonic signals,and eliminates the influence of the same frequency noise on the fuel consumption test accuracy by using the maximum likelihood estimate method.Cylindrical parameterization of the ultrasonic flow sensor by using 3 d coordinate method,together with the cylindrical fitting calculation of the geometric parameters of the ultrasonic flow sensor,solve the problem of the inaccurate measurement of the inner pipe diameter and acoustic path angle.The calculation of the correction coefficient of the fuel flow by adopting fluid mechanics theory,and the numerical simulation of the turbulent flow model by using fluent software,realize the fuel flow measurement of different flow patterns.Multi-path ultrasonic fuel consumption calculation model is improved by using the numerical integral method,and accurately calculate the position of ultrasonic flow sensor channel distribution and the weighting coefficient,correct and prove the integral of the mathematical model,further optimize the automobile fuel consumption test calculation model.The analysis of the error of automobile ultrasonic fuel consumption test mathematical model,the analysis of the automobile ultrasonic fuel consumption mathematical model based on the Gauss-Jacobi numerical integral method and Gauss-Legendre numerical integral method,contribute to the automobile fuel consumption error less than 0.1%,and verify the feasibility of high-precision automobile fuel consumption test theory.This dissertation lays the emphasis on analyzing the hardware structure and the performance requirements of the automobile ultrasonic fuel consumption test system,designing the control circuit of transmitting and receiving ultrasonic signals,designing and debugging the software of fuel consumption test system.It set up the experimental system of automobile ultrasonic fuel consumption,study the ultrasonic fuel consumption meter,put forward the revision plan of the ultrasonic fuel consumption testing system,actualize the calibration of fuel consumption instrument by using the instrument coefficient,further improve the testing precision of ultrasonic oil consumption meter.Based on the source of the uncertainty of the ultrasonic fuel consumption meter test,calculating the uncertainty of fuel consumption meter and evaluating the automobile fuel consumption meter.The result of uncertainty evaluation shows that the dispersion of automobile ultrasonic fuel consumption meter test result is small and the test quality is high.