Study On Database Of Vehicle Driving Cycles And Emission Rate Relation

Evaluation method of traditional laboratory to vehicles emissions, owing to its work condition can't reflect actual road driving behavior and vehicles' actual road emissions, the exploration 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 adopts on-board emissions test method to study vehicles actual road emissions in Tianjin City, analysising the road driving characteristic and the whole vehicle emissions characteristic of Tianjin City ,comparing the differences with the IVE model.The on-board emission test equipment which the text used is OBS-2200. Passing analysising 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, NOx is 5.4,THC is 7.1,consumedly higher than 1.2 of the law provisions. The relationship between the road vehicle driving cycle and the rate of emissions is analysised by the joint distribution of VSP and the emission rate. Different types of vehicle in technical depends on different emissions level. The EFI vehicles are better than carburetor vehicles. Exhaust gas recirculation technology improved the THC and CO emissions significantly.Tianjin with a higher proportion of idling traffic, a larger acceleration, highway traffic conditions compared with the fine, a variety of parameters to the contrary; the characteristics of the main road and slip between the above two and the slip with the poor road conditions, so the average speed was low. From the point of vehicle condition distribution of VSP, Tianjin VSP distribution is different from a lot of the typical foreign cities, and its distribution is rather narrow, and the vehicles engine work at low pressure mostly with the ratio as high as 95%. Very few car engine works in the high-pressure, that means China's urban road traffic conditions and determines the car can not smoothly travel at a higher speed. The actual characteristics of the road have huge differences compared with the current parameters used by motor vehicle exhaust emission test cycle, needing a large number of further experiments revise to adapt to China's specific conditions on the basis of the test cycle.Through study of the basic rate of emissions found that except medium-large displacement with EGR, IVE model estimate the CO2 emissions largely; while IVE model underestimate a lot of vehicles emissions of CO and THC with low-mileage and multi-point injection with three catalyst, and also underestimate some vehicles emissions of CO and THC with the middle mileage and multi-point injection with three catalyst. The automobile exhaust average emissions increase exponentially as the IVE model VSP-vehicle emission standards. Practical VSP- vehicle emissions curve are coincident with the standards curve of CO2 emissions fully, CO and NOX emissions are generally coincident with the standard curve, and HC has the worst compliance. To improve the accuracy of IVE model, we should increase the number of VSP-emission standards curve of more types vehicles and expand the experimental samples to obtain more local emissions rate data.