MESOSCOPIC FUEL CONSUMPTION AND EMISSION MODELING
MESOSCOPIC FUEL CONSUMPTION AND EMISSION MODELING
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发表时间：
2008-03
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通讯作者：
Huanyu Yue
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作者：
Huanyu Yue
运输部门是美国燃料消耗和排放的主要贡献者。因此，评估交通活动的环境影响是空气质量改善计划的关键。目前最先进的模型基于典型的城市驾驶循环来估计车辆排放。大多数这些模型提供简化的数学表达式来计算燃料消耗和排放率的基础上，平均链路速度，而忽略瞬态变化的车辆的速度和加速度水平，因为它行驶在公路网。或者，微观模型捕捉这些瞬态效应;然而，微观模型的应用可能是昂贵和耗时的。此外，这些工具可能需要输入数据分辨率的水平，而这是不可用的。因此，本文试图填补能源和排放建模的空白，建立一个框架，模拟汽车燃料消耗和排放的中观。这个框架是用来开发的VT Meso模型使用一些数据源。该模型使用最多三个独立变量，即：平均行驶速度、每单位距离的平均停车次数和平均停车持续时间，逐路段估算轻型车辆的平均油耗和排放率。介观模型利用弗吉尼亚理工大学开发的微观车辆燃料消耗和排放模型来计算特定模式的燃料消耗和排放率。该模型被称为VT-Micro，根据车辆的瞬时速度和加速度水平预测瞬时燃油消耗量和HC，CO和NOx的排放率。中观模型利用这些链路的输入参数来构建一个合成的驱动循环，并计算平均链路的燃料消耗和排放率。在构建驾驶循环之后，该模型估计车辆在链路上行驶时通常花费的巡航、减速、怠速和加速时间的比例。然后，使用一系列燃料消耗和排放模型来估计每种操作模式的燃料消耗量和HC、CO、CO2和NOX排放量。随后，通过对不同的操作模式求和并除以行驶的距离来估计车辆在沿着路段行驶时消耗的总燃料和排放的污染物，以获得基于距离的平均车辆燃料消耗和排放率。该模型是为正常和高排放车辆开发的。该研究量化了典型的驾驶员减速行为，以纳入模型。由于该模型构建了包括减速模式的驾驶循环，因此典型车辆减速行为的准确表征对于车辆排放的准确建模至关重要。该研究表明，虽然减速率通常会随着车辆接近其期望的最终速度而增加，但在整个减速机动中使用恒定的减速率足以用于环境建模目的。
The transportation sector is a major contributor to U.S. fuel consumption and emissions. Consequently, assessing the environmental impacts of transportation activities is essential for airquality improvement programs. Current state-of-the-art models estimate vehicle emissions based on typical urban driving cycles. Most of these models offer simplified mathematical expressions to compute fuel consumption and emission rates based on average link speeds while ignoring transient changes in a vehicle’s speed and acceleration level as it travels on a highway network. Alternatively, microscopic models capture these transient effects; however, the application of microscopic models may be costly and time consuming. Also, these tools may require a level of input data resolution that is not available. Consequently, this dissertation attempts to fill the void in energy and emission modeling by a framework for modeling vehicle fuel consumption and emissions mesoscopically. This framework is utilized to develop the VT-Meso model using a number of data sources. The model estimates average light-duty vehicle fuel consumption and emission rates on a link-by-link basis using up to three independent variables, namely: average travel speed, average number of stops per unit distance, and average stop duration. The mesoscopic model utilizes a microscopic vehicle fuel consumption and emission model that was developed at Virginia Tech to compute mode-specific fuel consumption and emission rates. This model, known as VT-Micro, predicts the instantaneous fuel consumption and emission rates of HC, CO and NOx of individual vehicles based on their instantaneous speed and acceleration levels. The mesoscopic model utilizes these link-by-link input parameters to construct a synthetic drive cycle and compute average link fuel consumption and emission rates. After constructing the drive cycle, the model estimates the proportion of time that a vehicle typically spends cruising, decelerating, idling and accelerating while traveling on a link. A series of fuel consumption and emission models are then used to estimate the amount of fuel consumed and emissions of HC, CO, CO2, and NOX emissions for each mode of operation. Subsequently, the total fuel consumed and pollutants emitted by a vehicle while traveling along a segment are estimated by summing across the different modes of operation and dividing by the distance traveled to obtain distance-based average vehicle fuel consumption and emission rates. The models are developed for normal and high emitting vehicles. The study quantifies the typical driver deceleration behavior for incorporation within the model. Since this model constructs a drive cycle which includes a deceleration mode, an accurate characterization of typical vehicle deceleration behavior is critical to the accurate modeling of vehicle emissions. The study demonstrates that while the deceleration rate typically increases as the vehicle approaches its desired final speed, the use of a constant deceleration rate over the entire deceleration maneuver is adequate for environmental modeling purposes.