| With the increasing of automobile consumption, automobile retain capacities are increasing. As a result, city environment becomes worse and worse. In China, the ratio of transportation gas pollution becomes bigger and bigger in some big cities, some of which even exceeds half of the total pollution. Reducing transportation gas pollution and controlling vehicle emission have become urgent affairs. However, at present the level of vehicle emission is low and the single vehicle emission factor is high in China. What's more, some means of transportation are relatively behindhand, the measure of traffic control and management are disadvantageous, and traffic demand contradiction makes vehicle operation conditions worse, which are the factors that greatly aggravate emission. To change the present situation, optimize traffic control and management to improve vehicle emission, this measure has strong point without changing means of transportation on road. This method mainly provides logical measure of traffic control and management, and seeks the high efficiency of transportation and environment protection through studying vehicle emission characteristic, micro emission model and the factors that effect vehicle emission performance in traffic flow. The key technology is the research on micro emission model in traffic flow. Therefore, research on the effect factors of vehicle emission performance and micro emission modeling are significant. Now the study on vehicle emission models have developed for many years, especially macro models which predict emission in macro region have developed to a mature degree. But in road net, intersection and some detailed regions, the emission predict has no effective measure. So in recent years, the overseas investigators commit themselves to micro emission model, and they have acquired some positive results. However in China the studies on vehicle emission effect factors and emission models have concentrated in several colleges and research institutes. On lacking in enough valid data, usually the investigators only rectify models that have exited in oversea. But because traffic condition, road establishment, vehicle condition and fuel quality in domestic areas are great different from them in overseas, simply copying and rectifying them are invalid. So it is necessary to make models suitable for China. On one side the research on emission factor on road and micro emission modeling are of importance,on the other side the establishment of vehicle emission model fit for China situation is of inevitability. Based on the above-mentioned two sides, study of Light-duty vehicle emission model on urban corridor has great significance in practice. Because the micro emission model is based on urban road, the model data should root in the real test on urban road. The on-board emission testing system in this paper can solve such a problem. The total system includes four parts: emission testing module, exhaust collecting module, engine sensors module, and vehicle run condition inspecting module. The emission measure instrument is OEM-2100, which is manufactured by Clean Air Technologies Inc. of USA, let alone its advancement. The on-board emission testing system collects emission data, engine rotate speed, intake pressure, intake temperature, and vehicle operation condition parameter ect. The data collected from experiments provide evidence for analysis on emission affecting factors and modeling of micro emission. The on-board emission testing system supplies a feasible method. To set up Light-duty vehicle emission model on urban road, I choose the typical roads in ChangChun, such as: Renmin Street, Changchun Street, Yatai Street and Nanhu Road, as study object. On these roads, by testing Multi Light-Duty vehicle emission, collecting a mass of data, I intend to pre-process the collection data. Then according to vehicle type, time, road, I gather and clean up the data respectively and calculate some relative data, which can offer good basis for further analysis and modeling. In real road, the factors that affecting on emission rate are multiple. In this paper several relatively important factors are chosen and analyzed. I analyze the emission rate change of operation conditions of Jetta, Jinbei, and Hongqi century star, these 3 types of vehicle. The result shows: emission of acceleration operation condition is much higher than that of other operation conditions, cruise operation condition is the second, deceleration is the third, and idle is the least. The characteristic of vehicle operation condition distribution on urban road is the proportion of idle, acceleration, and deceleration. The emission contribute rate of operation condition is that cruise is higher than acceleration, acceleration than -V -deceleration, deceleration than idle. Through comprising emission of the same vehicle on the same road under the conditions of high and low traffic, peak and natural traffic flow, it can draw a conclusion that vehicle operation period of time affect emission greatly. In detail, emission under high peak is the highest, traffic congestion is grave, the frequency of acceleration and deceleration is the highest; emission under low peak is the least, vehicle speed is relatively high; emission under natural traffic flow is medial. Experiments show in the first 5 seconds on acceleration, CO add rapidly, NOX hold the line basically, from 5 seconds to 10 seconds, NOX and HC also add rapidly. From deceleration to idle, about 10 seconds CO and NOX become stable, but HC keep high emission all along. Through the analysis of emission rate of vehicle affecting on speed and acceleration shows that: acceleration is one of the most important factors that affect emission rate, its high emission results from big acceleration, and NOX and CO emission rate are also affected greatly by the speed because burning temperature and degree of burning sufficiency are main factors that produce them. Based on analysis the effect on the rate of emission resulting from vehicle speed, acceleration and vehicle operation condition, I build up Speed Regression Model, Cruise emission rate model, idle emission rate model, Acceleration emission rate model, Deceleration emission rate model, Speed-acceleration two dimension high-hypo emission rate model and BP neural network emission rate model by using regression and neural network method. Models errors are all within 30%. So it is effective to predict instantaneous emission on real road. Speed Regression Model, Idle emission rate model, Acceleration emission rate model together with traffic simulation model can predict micro emission of urban road nets, provide some traffic control and management strategies. Two dimension model and neural network model are applicable in many areas. They fit for predicting light-duty vehicle micro emission on urban road. Since all models are based on Jetta emission data, they are limited. If predicting other light-duty vehicle emission, you can use coefficient method temporarily, i.e. multiply models by vehicle coefficient. This paper analyzes multiple factors that effect emission on roads; build up Light-duty vehicle emission models on urban typical road. These models can conveniently and accurately predict vehicle emission in urban traffic flow. They can also integrate traffic simulation software to accurately predict emission condition of a section of road and optimize traffic control and management. They...
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