Remotely detected vehicle mass from engine torque-induced frame twisting
Abstract. Determining the mass of a vehicle from ground-based passive sensor data is important for many traffic safety requirements. This work presents a method for calculating the mass of a vehicle using ground-based video and acoustic measurements. By assuming that no energy is lost in the conversion, the mass of a vehicle can be calculated from the rotational energy generated by the vehicle’s engine and the linear acceleration of the vehicle over a period of time. The amount of rotational energy being output by the vehicle’s engine can be calculated from its torque and angular velocity. This model relates remotely observed, engine torque-induced frame twist to engine torque output using the vehicle’s suspension parameters and engine geometry. The angular velocity of the engine is extracted from the acoustic emission of the engine, and the linear acceleration of the vehicle is calculated by remotely observing the position of the vehicle over time. This method combines these three dynamic signals; engine induced-frame twist, engine angular velocity, and the vehicle’s linear acceleration, and three vehicle specific scalar parameters, into an expression that describes the mass of the vehicle. This method was tested on a semitrailer truck, and the results demonstrate a correlation of 97.7% between calculated and true vehicle mass.
Quantifying Incremental Pavement Damage Caused by Overweight Trucks
Significant increases in commercial truck loadings across the Saskatchewan road network have resulted in accelerated damage to the provincial highway system. This accelerated damage has decreased the expected performance life of many of these roads and also increased maintenance and rehabilitation requirements and costs. Although provincial highways have maximum commercial legal load limits and most commercial carriers are compliant, it is inevitable that some trucks will exceed legal load limits. In the past, difficulties have been encountered in efforts to quantitatively account for incremental pavement damage due to overweight vehicles. With its aged state, the performance prediction of incremental damage on Saskatchewan highways resulting from commercial vehicle overloading is difficult to quantify using empirical highway design methods and pavement surface distress surveys. This study employed a mechanistic-based pavement analysis framework. Using Saskatchewan primary and secondary highway structural asset management data based on heavy weight deflectometer (HWD) network deflection data, the incremental damage from typical trucks operating on Saskatchewan highways was determined. In total, overloading the Saskatchewan highway network by 15 percent trucks (assuming 30,000 truck trips per day) province wide results in an overall daily cost of $621 per km per day and an overall annual cost of $226,677 per km per year. Based on the impact analysis carried out in this study, reducing the number of overweight trucks on Saskatchewan's highway network could significantly reduce road damage costs. Savings will not only be seen in terms of preservation and rehabilitation costs, but also in overall structural performance of the road. For the covering abstract of this conference see record control number 201111RT334E.
A Critical Assessment on Functional Attributes and Degradation Mechanism of Membrane Electrode Assembly Components in Direct Methanol Fuel Cells
Direct methanol fuel cells (DMFC) are typically a subset of polymer electrolyte membrane fuel cells (PEMFC) that possess benefits such as fuel flexibility, reduction in plant balance, and benign operation. Due to their benefits, DMFCs could play a substantial role in the future, specifically in replacing Li-ion batteries for portable and military applications. However, the critical concern with DMFCs is the degradation and inadequate reliability that affect the overall value chain and can potentially impede the commercialization of DMFCs. As a consequence, a reliability assessment can provide more insight into a DMFC component’s attributes. The membrane electrode assembly (MEA) is the integral component of the DMFC stack. A comprehensive understanding of its functional attributes and degradation mechanism plays a significant role in its commercialization. The methanol crossover through the membrane, carbon monoxide poisoning, high anode polarization by methanol oxidation, and operating parameters such as temperature, humidity, and others are significant contributions to MEA degradation. In addition, inadequate reliability of the MEA impacts the failure mechanism of DMFC, resulting in poor efficiency. Consequently, this paper provides a comprehensive assessment of several factors leading to the MEA degradation mechanism in order to develop a holistic understanding.