Study Of The Relation Of Vehicle's Driving Cycles And Emission Rate And Database

The pollution problem of vehicles to environment has already caused social extensive concern.Evaluation method of traditional laboratory to vehicles emissions,owing to its work condition can't reflect actual road driving behavior,can't completely reflect vehicles' actual road emissions,the exploiture of strategy of the vehicle emissions control also limits in the areas of the law stipulate working condition.In order to more thoroughly understand vehicles actual emissions,the text adoptes on-board emissions test method to study vehicles actual road emissions in Tianjin City,analysing the road driving characteristic and the whole vehicle emissions characteristic of Tianjin City.The on-board emission test equipment which the text uses is OBS-2200,an on-board real time vehicle road emission text system.Using this system,the vehicle instantaneous speed,engine temperature and press, environment temperature and press,volume concentraten of exhaust gases (CO,CO₂,NO_x and THC) can be tested and recorded with one even ten times per sec.All these data can be used to analyze exhaust behavior of the vehicle under realistic road condition and driving pattern.Some experiments has been made to certify the credibility and precision of the system.Passing analysing and researching the road type's proportion of Tianjin City,we confirm the test route,and adopted the above-mentioned on-board test technique to test more than 70 representative vehicles, the result shows that the emission factor of vehicle actual road emission is higher than testing in laboratory.The inferior coefficient of vehicle emission durable test is:CO is 6.2,NO_x is 5.4,THC is 7.1,consumedly higher than 1.2 of the law ordaining.Passing analysing and dealing wite the data of more than 70 vehicles, adopting unite distribution of driving power(speed*acceleraten),speed and emission rate to analysing the relation between vehicle road driving condition and emission rate.From researching the ralation of the waste gas quality emissions rate and the vehicle driving parameter, we find that the parameter described by V×A and the waste gas quality emissions rate exist corresponding relation, we define the V×A parameter and use it express vehicle driving power value. We study the choice of cell's number and numeric calculation in cell.We divide the V into 25 sects from the 0～130km/h according to the partition of 5km/h, divide the V×A into 25 sects from -35～30m²/s³ according to the partition of 2.5m²/s³, build up an emissions database including 625 cells.Each cell's emission rate in the database, according to the dissimilarity of its V and V×A's value, placing in different cells, calculating its average value in each cell.According to the technique type,emission mass and the using years, by using return curve and inserting value and correcting to calculate its emissions rate value,and getting actual driving emission rate of different vehicle according to different technique type and using years at last.Combining with Matlab,we empolder an analyzing software about the relation of vehicles' work condition and emissions,using it to analyse and deal with those data,we build up a new kind of database about the relation of vehicles' work condition and emission.We carry through a great deal of actual road test of typical model road in Tienjin City, obtaining various road type driving characteristic parameter.As a result,each kind of parameter on different road has different distribution characteristic.