Emission models are important tools for traffic emission and air quality estimates. Existing instantaneous emission models employ the steady-state “engine emissions map” to estimate emissions for individual vehicles. However, vehicle emissions vary significantly, even under the same driving conditions. Variability in the emissions at a specific driving condition depends on various influencing factors. It is important to gain insight into the effects of these factors, to enable detailed modeling of individual vehicle emissions. This study employs a portable emissions measurement system (PEMS), to collect vehicle emissions including the corresponding parameters of engine condition, vehicle activity, catalyst temperature, geography, and meteorology, to analyze the variability in emission rates as a function of those factors, across different vehicle specific power (VSP) categories. We observe that carbon dioxide, carbon monoxide, nitrogen oxides, and particle number emissions are strongly correlated with engine parameters (engine speed, torque, load, and air-fuel ratio) and vehicle activity parameters (vehicle speed and acceleration). In the same VSP bin, emissions per second on highways and ramps are higher than those on arterial roads, and the emissions when the vehicle is traveling downhill tend to be higher than the emissions during uphill traveling, because of higher observed speeds and accelerations. Morning emissions are higher than afternoon emissions, due to lower temperatures.

中文翻译：

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根据现场测试数据捕获瞬时车辆排放中的变异性

排放模型是交通排放和空气质量估算的重要工具。现有的瞬时排放模型使用稳态的“发动机排放图”来估计单个车辆的排放。但是，即使在相同的驾驶条件下，车辆的排放也会有很大差异。在特定驾驶条件下，排放的可变性取决于各种影响因素。重要的是要洞悉这些因素的影响，以便能够对单个车辆的排放进行详细的建模。这项研究使用便携式排放物测量系统（PEMS）来收集车辆排放物，包括发动机状况，车辆活动，催化剂温度，地理位置和气象学的相应参数，以分析排放率随这些因素的变化，跨不同的车辆特定功率（VSP）类别。我们观察到二氧化碳，一氧化碳，氮氧化物和颗粒物排放与发动机参数（发动机转速，扭矩，负载和空燃比）和车辆活动参数（车辆速度和加速度）密切相关。在同一个VSP箱中，高速公路和坡道上的每秒排放量高于干道上的每秒排放量，并且由于观察到的速度和加速度更高，车辆下坡行驶时的排放量往往高于上坡行驶时的排放量。由于温度较低，早晨的排放量高于下午的排放量。颗粒物的排放与发动机参数（发动机转速，扭矩，负载和空燃比）以及车辆活动参数（车辆速度和加速度）密切相关。在同一个VSP箱中，高速公路和坡道上的每秒排放量高于干道上的每秒排放量，并且由于观察到的速度和加速度更高，车辆下坡行驶时的排放量往往高于上坡行驶时的排放量。由于温度较低，早晨的排放量高于下午的排放量。颗粒物排放量与发动机参数（发动机转速，扭矩，负载和空燃比）和车辆活动参数（车辆速度和加速度）密切相关。在同一个VSP箱中，高速公路和坡道上的每秒排放量高于干道上的每秒排放量，并且由于观察到的速度和加速度更高，车辆下坡行驶时的排放量往往高于上坡行驶时的排放量。由于温度较低，早晨的排放量高于下午的排放量。并且由于观察到的更高的速度和加速度，车辆下坡行驶时的排放往往高于上坡行驶时的排放。由于温度较低，早晨的排放量高于下午的排放量。并且由于观察到的更高的速度和加速度，车辆下坡行驶时的排放往往高于上坡行驶时的排放。由于温度较低，早晨的排放量高于下午的排放量。