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Studies of emissions from vehicles equipped with catalysts have shown that some unregulated emissions can increase when a catalyst is used. One example of this is sulfuric acid, which has been studied extensively. Other unregulated emissions include ammonia and hydrogen cyanide. In a number of studies, these unregulated pollutant emissions have been measured from light-duty vehicles and heavy-duty engines. These emission levels were used in air quality dispersion models to predict the resultant air quality levels. The ambient concentrations predicted for each pollutant were then compared to suggested concentrations at which adverse health effects may be found to determine if additional monitoring or control would be indicated for these pollutants. It was determined that mobile source emissions of sulfuric acid, hydrogen cyanide, and ammonia do not in general result in ambient levels of concern for the air quality situations studied.

A stratified charge research engine and test stand were designed and built for this work. The engine was designed to exhibit some of the desirable traits of both the premixed charge gasoline engine and modern diesel engine. This spark ignition engine is fueled by M100 (99.99% pure methanol), operates under high compression (19.3:1) and uses direct fuel injection to form a stratification of the fuel-air mixture in the cylinder. The beginning of the combustion event of the stratified mixture is triggered by spark plug discharge. The primary goal of this project was to evaluate the feasibility of using a removable integral injector ignition source insert, which allows a convenient method of changing the relative location of the fuel injector to the ignition source, as well as the compression ratio, squish height, and bowl volumes. This paper provides an explanation of the hardware included in the experimental setup of the engine and selection of the direct injector configuration.

This paper describes the development of adjustment factors applicable to the EPA City and Highway MPG values. The paper discusses the data bases used, and the analytical methods employed to arrive at adjustment factors of 0.90 for the EPA City MPG value and 0.78 for the EPA Highway MPG value.

The Schatz Heat Battery stores excess heat energy from the engine cooling system during vehicle operation. This excess energy may be returned to the coolant upon the ensuing cold start, shortening the engine warm-up period and decreasing cold start related emissions of unburned fuel and carbon monoxide (CO). A Heat Battery was evaluated on a test vehicle to determine its effect on unburned fuel emissions, CO emissions, and fuel economy over the cold start portion (Bag 1) of the Federal Test Procedure (FTP) at 24°C and -7°C ambient conditions. The Heat Battery was mounted in a vehicle fueled alternately with indolene clear (unleaded gasoline) and M85 high methanol blend fuels. Several Heat Battery/coolant flow configurations were evaluated to determine which would result in lowest cold start emissions.

The cyclic and steady-state vehicle emissions, fuel economy, performance, and cold start behavior of an automobile equipped with a direct injection methanol engine are compared with those of three other comparable vehicles. One of the comparable vehicles was powered by a gasoline-fueled engine, and the other two were Diesels. One of the Diesel-powered vehicles was naturally aspirated and the other was turbocharged. All evaluations were made using the same road load horsepower and equivalent test weight. All the evaluations were conducted at low mileage. The emissions of the methanol vehicle are compared to California low emission vehicle standards, and to the emissions of another methanol vehicle.

The fuel economy data obtained from the emission tests run by the U.S. Environmental Protection Agency (EPA) have been used to show passenger car fuel economy trends from model year 1957 to present. This paper adds the 1975 model year to the historical trend and concentrates on comparisons between the 1975 and 1974 models. Methodologies which allow different 1975 vs 1974 comparisons to be made have been developed. These calculation procedures allow the changes in fuel economy to be determined separately for emission control systems, new engine-vehicle combinations and model mix shifts. Comparisons have been calculated not only for the fleet as a whole but for each of the 13 manufacturers who were certified as of the time this paper was prepared. The net change in fuel economy for the fleet has been estimated at +13.8% comparing the 1975 models to the 1974 models assuming no model mix change occurs.

A high-speed/high-resolution imaging technique and analysis were applied to study fuel injector spray timed evolution in ambient air and in a motored single-cylinder engine. Alcohol fuel was injected from a mid-pressure injection system into the engine cylinder at shaft speed of 1,000 rpm. The fuel injection system with various nozzles was designed for use in the EPA/NVFEL program to develop clean and efficient engines that use alternative fuels. A 15W copper vapor laser with a fiber optic delivery system synchronized with a high-speed drum streak camera was utilized to expose films at 5,000 frames per second (fps). The spray characteristics were investigated at 15.0 MPa injection pressure and injection duration range of 3-5 ms. A sequence of successive frames was selected from the films to examine the influence of the injector parameters and the valve lift on the atomization process. The spray penetration was quantified by analyzing the high-speed films.

EPA Fuel economy figures are presented for model year 1982 cars and light duty trucks. Comparisons with the MPG figures of prior years are included. Sales penetrations of various vehicle, engine, and emission control design features are given, and domestic cars' MPG characteristics are compared to that of imports', gasoline vehicle MPG is compared to Diesel MPG, and 49-states MPG is compared to California MPG. Usage of newer vehicle technologies is continuing to increase, leading to continued growth in fuel economy capability in spite of stringent emission standards.

This is an analysis of fuel economy data compiled by the U.S. EPA on passenger cars from model years 1958-1978, and light-duty trucks from 1975-1978. The paper includes new fuel economy data on pre-1975 cars, which indicates that fleet average MPG for the older models is slightly higher than had been previously estimated. Analysis of 1977-78 passenger cars and light trucks' economy characteristics in terms of the new EPA/DOE “Vehicle Size” classes provides new insight into fleet MPG characteristics as related to model changes. The methodology for isolating fleet and individual manufacturer fuel economy changes due to specific factors such as system optimization and weight mix shifts has been refined, and is applied for the first time to trucks and to comparison of 49-states and California vehicles. The vehicle fleet which is the basis of the analysis includes the top-selling 18 car makers and 8 truck manufacturers.

EPA new-model fuel economy figures are presented for passenger vehicles and light duty trucks (those with GVW ratings up to 8500 lbs). The 1981 models are emphasized, with some comparisons to prior years included. Reader familiarity with the EPA tests, data bases, and analytical methods is assumed. Principal two-way analyses include comparisons of domestic vs. import, gasoline vs. Diesel, and Federal (49-state) vs. California vehicles. Sales fractions for a number of vehicle and engine emission control design features are included. The principal finding is that increased use of newer vehicle and emission control technologies in 1981 has accompanied significant fuel economy gains in spite of the tougher 1981 emission standards.

The fuel economy data compiled by the U.S. Environmental Protection Agency (EPA) have been analyzed to determine the trends in passenger car fuel economy beginning with model year 1958. Light duty truck fuel economy has been examined beginning with the 1976 model year. This paper adds the 1977 model year data to the historical trend and concentrates on the comparisons between the 1976 and 1977 models and the 1977 California and 49-state fleets. Calculation procedures have been used on the passenger car data which allow the changes in fuel economy due to system optimization, new engine/vehicle combinations, and weight mix shifts to be determined separately for individual manufacturers and the fleet as a whole. The passenger car fleet consists of the 13 manufacturers which were certified by September 13, 1976. Seven manufacturers comprise the light duty truck fleet.

The pre-1975 EPA fuel economy data base has been expanded to over 6,600 cars, and these data on older cars have been adjusted for odometer mileage effects on fuel economy. The data base for model year 1975-1977 certification cars is also updated, reflecting actual sales figures. The resulting trend analyses are thus (for the first time) consistent from year to year with regard to the representation of actual sales weighted new-car fleet fuel economy. Data on the 1979 fleet is presented in detail, and compared with that of the 1978 fleet, on the basis of projected sales for those two years. Comparisons with pre-emission control MPG, which serve as measures of technological change accompanying increasingly stringent emission standards, are accordingly revised from previous publications (1)* on this subject.

This, the eleventh in a series of Papers on EPA fuel economy trends, emphasizes the current Model Year (1983) as usual, but also gives increased emphasis to trends in vehicle technology, including catalyst and transmission subclasses. Final “CAFE”* production volumes and MPG figures have been used to update the data bases through the 1980 Model Year, and an analytic method used in the past to allocate year-to-year fleet MPG changes to specific causes, such as weight mix shifts, has been reinstituted. Conclusions are presented on the relation between fuel economy and emission standards, catalyst types, and transmission types.

This, the fourteenth in this series of papers, examines trends in fuel economy, technology usage and estimated 0 to 60 MPH acceleration time for model year 1986 passenger cars. Comparisons with previous year's data are made for the fleet as a whole and using three measures of vehicle/engine size: number of cylinders, EPA car class, and inertia weight class. Emphasis on vehicle performance and fuel metering has been expanded and analysis of individual manufacturers has been deemphasized; comparisons of the Domestic, European, and Japanese market sectors are given increased emphasis.

This, the fifteenth in this series of papers, examines trends in light-duty vehicle fuel economy and technology usage for model years 1978 through 1987. Comparisons with previous years’ data are made for the fleet as a whole and for number of cylinders, vehicle size class, inertia weight class, and market segment (Domestic, European, and Asian).

Numerical simulations of lean Methanol combustion in a four-stroke internal combustion engine were conducted on a high-compression ratio engine. The engine had a removable integral injector ignition source insert that allowed changing the head dome volume, and the location of the spark plug relative to the fuel injector. It had two intake valves and two exhaust ports. The intake ports were designed so the airflow into the engine exhibited no tumble or swirl motions in the cylinder. Three different engine configurations were considered: One configuration had a flat head and piston, and the other two had a hemispherical combustion chamber in the cylinder head and a hemispherical bowl in the piston, with different volumes. The relative equivalence ratio (Lambda), injection timing and ignition timing were varied to determine the operating range for each configuration. Lambda (λ) values from 1.5 to 2.75 were considered.

A numerical study on the combustion of Methanol in a directly injected (DI) engine was conducted. The study considers the effect of the bowl-in-piston (BIP) geometry, swirl ratio (SR), and relative equivalence ratio (λ), on flame propagation and burn rate of Methanol in a 4-stroke engine. Ignition-assist in this engine was accomplished by a spark plug system. Numerical simulations of two different BIP geometries were considered. Combustion characteristics of Methanol under swirl and no-swirl conditions were investigated. In addition, the amount of injected fuel was varied in order to determine the effect of stoichiometry on combustion. Only the compression and expansion strokes were simulated. The results show that fuel-air mixing, combustion, and flame propagation was significantly enhanced when swirl was turned on. This resulted in a higher peak pressure in the cylinder, and more heat loss through the cylinder walls.

Three-dimensional transient simulations using KIVA-3V were conducted on a 4-stroke high-compression ratio, methanol-fueled, direct-injection (DI) engine. The engine had two intake ports that were designed to impart a swirling motion to the intake air. In some cases, the intake system was modified, by decreasing the ports diameter in order to increase the swirl ratio. To investigate the effect of adding shrouds to the intake valves on swirl, two sets of intake valves were considered; the first set consisted of conventional valves, and the second set of valves had back shrouds to restrict airflow from the backside of the valves. In addition, the effect of using one or two intake ports on swirl generation was determined by blocking one of the ports.

The offset (sometimes called “shortfall”) between EPA MPG and actual in-use MPG has been shown to be dependent upon vehicle technology and EPA MPG level. If these variables change significantly, there is the potential for the constant EPA MPG adjustment factors (0.90 city, 0.78 highway) to become obsolete. Trends in passenger car MPG have been used to formulate a model of vehicle technology mixes and MPG levels over the next 15 years, to investigate the degree to which MPG adjustments derived from such a scenario might differ from the promulgated constant adjustment factors. As a check on the reasonableness of the future technology scenario, a simple econometric model was constructed independently which relates car class market fractions and MPG levels to gasoline price, and to regulatory requirements: MPG Standards and the Gas Guzzler tax.