车辆载重对重型货车碳排放的影响

Impact of Vehicle Load on Heavy-Duty Vehicle Carbon Emissions

现有交通碳排放模型对重型车在实际路况下的载重变化特性考虑不足,尚未从微观排放率角度分析载重对车辆排放的影响,从而造成碳排放测算的不确定性较大。针对此问题,首先采集大规模的实际路况下重型货车运行工况和油耗数据,使用基于油耗的CO_(2)排放测算模型计算重型货车的CO_(2)排放量;然后对不同类别的货车分类讨论,使用基于VSP的排放模型研究车辆载重对CO_(2)排放的影响,并建立考虑车重的LC-VSP排放模型,再与传统MOVES模型进行排放测算误差的对比。研究结果显示,载重对重型货车CO_(2)排放率、VSP分布都会产生显著影响,进而显著影响CO_(2)排放因子,具体表现为:①当VSP处于较小的正区间时,CO_(2)排放率随载重的增加而线性增大;②在相同速度区间,随着载重的增加,VSP分布的均值和方差都会逐渐减小;③在平均工况下,根据车型的不同,满载相较于空载的CO_(2)排放因子增加了约24%~113%,当车辆速度较低(小于20 km/h)时,载重对CO_(2)排放因子影响显著,车辆满载(49 t)时的CO_(2)排放因子为车辆空载(18 t)时的2.8倍,但随着速度的提高,载重对CO_(2)排放因子的影响逐渐减小;④相较于不考虑车辆实际载重的排放模型,考虑车辆实际载重时CO_(2)排放测算误差可以减小3%~12%。这一结果强调了在排放测算中考虑车辆载重的必要性,为精准的排放建模和评估提供了一定的理论依据。

The existing issues that current transportation carbon emission models do not adequately consider the load variation characteristics of heavy-duty vehicles under real-world road conditions,and have not yet analyzed the impact of vehicle load on emissions from the perspective of microscopic emission rates,lead to the biggish uncertainty of carbon emission estimation.To address this issue,firstly,extensive data on the operational conditions and fuel consumption of heavy-duty trucks under real-world conditions were collected.A fuel consumption-based CO_(2)emission calculation model was used to calculate the CO_(2)emissions of heavy-duty trucks.Then,different categories of trucks were classified and discussed.An emission model based on VSP(Vehicle Specific Power)was used to study the impact of vehicle load on CO_(2)emissions,and a LC-VSP(Load-Considered VSP)emission model considering vehicle weight was established.A comparison was made between the LC-VSP model and the traditional mobile source emissions model MOVES(Motor Vehicle Emission Simulator Model)in terms of emission calculation errors.The results of the research indicate that load capacity has a significant impact on CO_(2)emission rates and VSP distribution of heavy-duty trucks,thus significantly affects the CO_(2)emission factors,as follows:①When VSP is in a small positive range,CO_(2)emission rates linearly increase with the increase of load;②In the same speed range,with the increase of load,the mean and variance of VSP distribution gradually decrease;③Under average operating conditions,the CO_(2)emission factors for fully loaded vehicles increase by approximately 24%to 113%compared to empty vehicles,depending on the vehicle type.When the vehicle speed is low(less than 20 km/h),the load has a significant impact on CO_(2)emission factors.The CO_(2)emission factor of fully loaded vehicles(49 t)is 2.8 times that of empty vehicles(18 t).However,as the speed increases,the impact of load on CO_(2)emission factors gradually diminishes;④Compared to emission models that do not consider the actual vehicle load,considering actual vehicle load can reduce CO_(2)estimation errors by 3%to 12%.It emphasizes the necessity of considering vehicle load in emission estimations,providing a certain theoretical basis for accurate emission modeling and assessment.