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Cost is one of the critical factors in the commercialization of PEM fuel cells in automotive markets. Arthur D. Little has been working with the U.S. Department of Energy, Office of Transportation Technologies to assess the cost of fuel-flexible reformer proton exchange membrane (PEM) fuel cell systems based on near-term technology but cost modeled at high production volumes and to assess future technology scenarios. Integral to this effort has been the development of a system configuration (in conjunction with Argonne National Laboratories), specification of performance parameters and catalyst requirements, development of representative component designs and manufacturing processes for these components, and development of a comprehensive bill of materials and list of purchased components. The model, data, and component designs have been refined based on comments from the Freedom Car Technical Team and fuel cell system and component developers.

The task of matching engine, control system and catalytic converter has become very complex as the automotive industry strives to meet stringent demands for pollution abatement. To address the need for a robust, accurate modeling tool we have created a microkinetics-based simulation program that describes the reactions taking place on the surface of a catalytic converter. This chemically detailed approach permits the construction of faithful simulations of both steady state and transient performance of the catalyst using a combination of experimental measurements, literature data and quantum chemical calculations. The model can be coupled to existing simulations of the engine and control elements, notably those based on GT-Power.

A corona discharge device (CDD) used in conjunction with automotive stoichiometric catalysts has been shown to be effective in reducing exhaust tailpipe emissions and catalytic converter light-off temperatures. The CDD used here is a low power, low cost corona discharge device mounted ahead of the catalytic converter in the exhaust stream. Creation of radicals and other oxidizing species in the exhaust by the non-thermal plasma is shown to significantly improve catalyst conversion efficiencies for HC, CO and NOx. Burner flow data shows improvement in steady-state conversion efficiencies as well as improved catalyst light-off performance. Engine-dynamometer and vehicle data on spark ignition engines using production type (stoichiometric) control also shows improved performance with aged catalysts, and various levels of fuel sulfur. The reversibility of sulfur poisoning was also observed.

A cold-start partial oxidation (POX) system was integrated with a modern flexible fuel engine to assess its impact on cold-start performance and emissions. The POX reactor, a small combustion device operating fuel rich, converts liquid fuel into gaseous fuel species (reformate). The reformate from the reactor, when mixed with combustion air, replaces or supplements the standard fuel consumed during an engine start. This prototype integrated cold-start system has successfully reduced emissions from a cold-start on fuel grade ethanol (E95) at 5°C. The integrated POX system reduced the time-averaged hydrocarbon (HC) and carbon monoxide (CO) emissions by 80 and 40 percent, respectively. Starts on E95 reformate were achieved in less than 10 seconds at temperatures as low as -20°C.

Arthur D. Little in conjunction with the Department of Energy and the Illinois Department of Commerce and Community Affairs are developing an ethanol fuel processor for fuel cell vehicles. Initial studies were carried out on a 25 kWe catalytic partial oxidation (POX) reformer to determine the effect of equivalence ratio, steam to carbon ratio, and residence time on ethanol conversion. Results of the POX experiments show near equilibrium yields of hydrogen and carbon monoxide for an equivalence ratio of 3.0 with a fuel processor efficiency of 80%. The size and weight of the prototype reformer yield power densities of 1.44 l/kW and 1.74 kg/kW at an estimated cost of $20/kW.

The vast majority of cars and small trucks are sold with factory installed air conditioning (approximately 80% in 1989). For electric vehicles to succeed in the marketplace, air conditioning will need to be offered as optional equipment, along with adequate heating and defrosting systems. While providing the level of cooling performance expected by vehicle operators, it is important that the power consumption of the air conditioning systems used in electric vehicles be minimized, to minimize penalties to vehicle range and performance. Due to the ongoing CFC-12 phase-out, air conditioning systems intended for EV applications beyond the early 1990's must use an environmentally acceptable alternative refrigerant. This paper summarizes the design of a variable speed Scroll compressor based prototype air conditioning system for an electrically powered mini-van. The system refrigerant is HFC-134a and high performance heat transfer components are utilized.

The vast majority of cars and small trucks are sold with factory installed air conditioning (approximately 80% in 1989). For electric vehicles to succeed in the marketplace, air conditioning will need to be offered as optional equipment, along with adequate heating and defrosting systems. While providing the level of cooling performance expected by vehicle operators, it is important that the power consumption of the air conditioning systems used in electric vehicles be minimized, to minimize penalties to vehicle range and performance. This paper summarizes the design and performance of several air conditioning systems that have been developed for electric vans over the past two years, including systems based largely on standard automobile air conditioning components and more advanced systems using high performance heat transfer components and a variable speed refrigerant compressor.

The influence of charge motion and fuel injection characteristics on diesel combustion was studied in a rapid compression machine (RCM), a research apparatus that simulates the direct-injection diesel in-cylinder environment. An experimental data base was generated in which inlet air flow conditions (temperature, velocity, swirl level) and fuel injection pressure were independently varied. High-speed movies using both direct and shadowgraph photography were taken at selected operating conditions. Cylinder pressure data were analyzed using a one-zone heat release model to calculate ignition delay times, premixed and diffusion burning rates, and cumulative heat release profiles. The photographic analysis provided data on the liquid and vapor penetration rates, fuel-air mixing, ignition characteristics, and flame spreading rates.

Three widely documented methods for the analysis of aliphatic aldehydes in air, i.e., chromotropic acid, 3-methyl-2-benzothiazolone hydrazone (MBTH) and 2, 4-dinitrophenyl hydrazone (DNPH), and a modified version of the MBTH method are frequently used for the analysis of aldehydes in diluted diesel exhaust. In order to assess their relative accuracy for analysis of aldehydes in such a matrix, a side-by-side comparison of the methods was conducted. The equivalent accuracy of the chromotropic acid, MBTH and DNPH methods for analysis of formaldehyde in a clean air matrix was confirmed and a negative bias in the MBTH method as a result of SO2 interference was documented. A comparison of the concentrations of formaldehyde and aliphatic aldehydes in diluted diesel exhaust measured by the four methods indicates that significant differences exist between several of them.

Several characteristics distinguish the combustion in large-bore engines from ordinary automotive engines; namely low rpm and associated long combustion duration, natural gas fuel, multiple spark plugs, lean (Φ ≈ 0.8) operation, substantial unmixedness due to direct gas injection during compression, and low surface to volume ratio. In order to better appreciate the effects of these factors on NOx formation, a phenomenological model of combustion in a 20-inch bore two-cycle natural gas engine is described. The model accounts for random “unmixedness” of the initial charge, stratification, and temperature gradients arising from successively burned zones. Predictions are compared with experimental data for the effects of variations in timing, fuel-air ratio, stratified charge, EGR, and turbulence.

A study was conducted to determine the potential reduction in automotive fuel consumption based on the use of innovative systems and improved components. Technological areas investigated were: spark ignited engines with and without turbocharging, electronic feedback controlled fuel injection with duel bed catalytic converters, stratified charge combustion, light weight diesels, lock-up torque converters, continuously variable ratio transmission, tires aerodynamic drag, vehicle weight, engine accessories and optional equipment. Standard and compact-size 1973 model year vehicles were selected for analysis using a computer-simulation program to predict fuel usage and performance with and without incorporation of the improvements. In addition estimates were made as to whether modified vehicles complied with study constraints such as emission, safety, noise and user requirements.

Sensory studies have described diesel exhaust odor in terms of two major odor character groups-oily-kerosene and smoky-burnt. The odorous compounds have been identified in a detailed analytical chemistry-odor study. The oily-kerosene odor group is associated with the aromatic portion of the unburned fuel-principally, the alkyl substituted benzenes, indans, and tetralins. The smoky-burnt odors arise from partial combustion products of the paraffin and aromatic fuel components. Our studies have shown a good correlation between exhaust odor intensity and abundance of the partial combustion products. An analytical method has been developed, based on liquid chromatography, for the quantitative expression of exhaust odor intensity by measurement of the smoky-burnt odor group. Initial survey studies show the method to be applicable over a wide odor emission range. Fuel variation has little effect, whereas injector variables do influence odor intensity.