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In recent years emission control agencies have turned their attention to to the cleanup of diesel engines, both mobile and stationary. This paper is one of the first attempts to characterize the load and emissions of a subsection of stationary diesel emissions, specifically Truck/Trailer Refrigeration Units (TRUs). These devices are used to keep refrigerated or frozen cargo cold when it is being shipped/delivered. Two general sizes of TRUs were tested, smaller TRUs for cooling box trucks, used for local deliveries, and large TRUs, used for long hauling and very large deliveries. After observing a matrix of these units over a large spectrum of temperatures it was found that, although there were multiple control strategies, they all heavily relied on pulling the trailer down to the set point temperature as fast as the engine and refrigeration unit would allow.

This paper presents model-based predictions of the performance of diesel, compressed natural gas (CNG), and hybrid buses on bus routes in the City of San Francisco. The bus route details were obtained by recording time-series measurements of speed and grade during actual runs of buses on the city streets under different traffic conditions. The transit buses' physical and mechanical characteristics were obtained from manufacturers' data and chassis dynamometer testing of the buses on different city cycles. Both the bus routes and the bus performance characteristics were put into the simulation package ADVISOR from the National Renewal Energy Laboratory (NREL). The most extreme results were for the San Francisco routes that have high grades. The high grades cause performance and emissions problems for both the diesel and CNG buses relative to the hybrid bus.

In the last five years, there have been multiple demonstrations of fuel cell auxiliary power units (APUs) which provide power in lieu of idling of the main vehicle engine. The Institute of Transportation Studies at the University of California Davis has designed and evaluated a retrofitted, proton exchange membrane (PEM) fuel cell APU for powering accessories in heavy-duty truck cabs. The performance objectives for the system were determined based on truck driver feedback and industry design guidelines. The final FC APU system was developed to run for 3 days between refueling at a power output of 1.8 kW. The primary goals were to utilize exclusively commercially available components and to minimize costs. This paper discusses the performance targets, design tradeoffs, and evaluation of the developed system.

Line-haul truck engines are frequently idled to power hotel loads (i.e. heating, air conditioning, and lighting) during rest periods. Comfortable cabin climate conditions are required in order for mandatory driver rests periods to effectively enhance safety; however, the main diesel engine is an inefficient source of power for this conditioning. During idle, the diesel engine operates at less than 10% efficiency, consuming excess diesel fuel, generating emissions, and accelerating engine wear. One promising alternative is the use of small auxiliary power units (APUs), particularly fuel cell-based APUs. The Institute of Transportation Studies (ITS-Davis) developed an ADVanced VehIcle SimulatOR (ADVISOR)-based model to quantify the costs and benefits of truck fuel cell APUs. Differences in accessories, power electronics, and control strategy between the conventional engine idling and APUequipped systems are analyzed and incorporated into the model.

In the immediate future the introduction of a wider variety of fuel types will play a significant role in reducing emissions and in solving the energy needs of the transportation industry. Both compressed natural gas, CNG, and hydrogen are expected to play very large roles, and the present paper shows that these fuels, when used together, can offer large benefits in NOx emissions. Significant reductions in NOx emissions will be required for CNG transit buses and heavy duty trucks, if they are to meet the future stringent emissions standards that come into effect in the year 2007. In the present paper a detailed engine model was used to understand and predict the results from engine dynamometer tests from a production automotive engine over a range of hydrogen/CNG gas fuel mixtures.

As part of a California Selective Catalyst Reduction (SCR) system demonstration and evaluation project [13], the authors and their industrial partners have conducted engine dynamometer emissions tests of SCR systems. The transient Federal Test Procedure (FTP) cycle and 13 Mode European Stationary Cycle (ESC) were conducted using certification diesel fuel with 300-500 ppm of sulfur. This paper reviews the performance of the first system to meet the goal of attaining 1 g/bhp-hr NOx emissions in the transient FTP cycle on a 1999 DDC Series 60 engine that has an initial 4 g/bhp-hr level. This paper discusses key characteristics of a typical automotive SCR system and then presents the results and analysis of the engine dynamometer emission testing of a SCR system. The paper concludes with a discussion of the challenges involved in on-road operation of the system.

Class 8 trucks idling consume significant amounts of diesel fuel each year in North America and abroad. Engine idling occurs to power sleeper compartment accessories (air conditioners, refrigerators, televisions), and to avoid start-up problems. The alternative power sources available to reduce the need for idling (i.e. battery packs, auxiliary generators, direct-fired heaters, absorption coolers) all have severe economic and technical drawbacks that have limited their market acceptance. Freightliner Corporation, in conjunction with its development partner XCELLSiS Corp. has constructed a fully functioning concept demonstration vehicle that utilizes Proton Exchange Membrane (PEM) fuel cell technology in an auxiliary power unit (FC APU). While fuel cell powertrains continue to face significant technical and economic barriers, with additional development truck auxiliary power applications may offer a viable near-term market for small (1 - 5 kW) fuel cells.

The Institute of Transportation Studies at the University of California, Davis (ITS-Davis) has brought together a group of public and industrial partners to demonstrate and evaluate the Siemens-Westinghouse Urea-Selective Catalyst Reduction System (SINOx™). The SINOx System has the potential to generate major reductions in nitrogen oxides (NOx) and the volatile organic fraction (VOF) of particulate (PM) from heavy-duty diesel engines, without increasing fuel consumption and carbon dioxide (CO2) emissions. This demonstration began with engine bench testing at Detroit Diesel Corporation to calibrate the system to attain 1 g/bhp-hr NOx emissions in the transient portion of the US-FTP on a 1999 Series 60 engine that has a 4 g/bhp-hr emission level. The second phase of the project entails an on-highway demonstration of a set of ten, Freightliner Class 8 heavy-duty diesel vehicles. These vehicles are part of the Valley Material Transport fleet based in French Camp, California.