Design And Research Of Vehicle-carried Data Acquisition System Used For Development Of Driving Cycles

Our country has not yet exploited the "Chinese driving cycles" according to the actual situation of road traffic until now.The emissions and fuel consumption state standards of kinds of vehicles still adopt European or international vehicle test cycles.Some domestic related researches indicate that there are remarkable differences between domestic and Europe in the aspects of road traffic conditions,road type,geographic features and trip characteristics.The test results don't reflect the vehicles' actual-road driving fuel consumption and emission levels when using European cycles on fuel consumption and emissions tests.Therefore it's very meaningful to develop our own country's actual typical vehicle driving cycle according to our country real road traffic.One of the most important task is to exploit the data acquisition system,which used for obtaining a large amount of data on vehicles' real riding condition.The thesis firstly generalizes the tendency of data acquisition system at home and abroad used for collecting vehicles' cycle data.Secondly summarize the cycles' development methods around the world and compare the main three cycles' characteristics.To further illustrate the necessity of developing Chinese cycle,analysis the vehicle' emissions difference under three kinds of cycles through the drum test.Than find out three specific characteristics of vehicle driving data collecting system,compared with the data acquisition systems which have other applications.They respectively are parameters' category,sampling frequency and real-time performance.Than determine the parameters' category and acquisition method by studying the ISO15031 protocol,including the formula of instantaneous fuel consumption.Thirdly finish the overall solution design of the data acquisition system which used for test cycle's development.Than set up hardware platform of the data acquisition system,including the introduction of the modules and interface circuit design.Build the software development environment,transplanted ?C/OS-II system and set up five parallel subtasks program,including GPS data receiving and parsing,CAN initialization,CAN sending&receiving message,GPRS connection and data sending.Finally validate the designed functions of the system.A drum test has been conducted in order to verify the precision of the module of instantaneous fuel consumption.The result indicates that the formula model has a good accuracy.In real vehicle tests,verify the accuracy of the acquisition parameters,which can satisfy the requirements of the item.So as to study the effect of sampling frequency to the collected driving cycle,analysis six kinds data collecting by different sampling frequency.Results indicate that the sampling frequency effect on the driving cycle significantly.Compared with the impact on speed,the impact on the acceleration is bigger.It will miss the larger acceleration value,when the sampling frequency is too small,at the same time it also will underestimate the idle speed and low speed ratio.The data acquisition system which used for developing driving cycle in this thesis provids a powerful tool and equipment support for the project,also a useful exploration and experience for collecting vehicles' driving data.Besides,this thesis provides basis and guidance for vehicles' driving data collecting through study the effect of sampling frequency to the collected driving cycle.