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The pressing need to improve U.S. energy independence and reduce climate forcing fossil fuel emissions continues to motivate the development of high-efficiency internal combustion engines. A recent trend has been to downsize and turbocharge automotive spark-ignited engines coupled with direct fuel injection to improve engine efficiency while maintaining vehicle performance. In-line with recent trends in state-of-the-art engine technology, the focus of this study is lean and EGR dilute combustion in a gasoline direct injection (GDI) engine. The lean and dilute operating limits are defined by combustion stability typically in terms of COVIMEP so experiments were carried out on an automotive size single-cylinder research engine to characterize combustion stability. From a 20,000 cycle sequence analysis, lean operating conditions exhibit binary high- to low-IMEP cycle sequences. This may be because the cycle-to-cycle feedback mechanisms are physically limited to one or two cycles.

The Natural Gas Vehicle (NGV) Challenge '92, was organized by Argonne National Laboratory. The main sponsors were the U.S. Department of Energy the Energy, Mines, and Resources - Canada, and the Society of Automotive Engineers. It resulted in 20 varied approaches to the conversion of a gasoline-fueled, spark ignited, internal combustion engine to dedicated natural gas use. Starting with a GMC Sierra 2500 pickup truck donated by General Motors, teams of college and university student engineers worked to optimize Chevrolet V-8 engines operating on natural gas for improved emissions, fuel economy, performance, and advanced design features. This paper focuses on the results of the emission event, and compares engine mechanical configurations, engine management systems, catalyst configurations and locations, and approaches to fuel control and the relationship of these parameters to engine out and tailpipe emissions of regulated exhaust constituents.

A production spark ignition engine powered vehicle (3.1-L Chevrolet Lumina, model year 1990) was tested with oxygen-enriched intake air containing 25 and 28% oxygen by volume to determine if (1) the vehicle would run without difficulties and (2) there would be emissions benefits. Standard Federal Test Procedure (FTP) emissions test cycles were run satisfactorily without vehicle performance anomalies. The results of catalytic converter-out (engine with a three-way catalytic converter in place) emissions showed that both carbon monoxide and hydrocarbons were reduced significantly in all three phases of the emissions test cycle, compared with normal air (21 % oxygen). Carbon monoxide emissions from the engine (with the three-way catalytic converter removed) were significantly reduced in the cold-phase of the test cycle. The catalytic converter also had an improved carbon monoxide conversion efficiency under the oxygen-enriched air conditions.

Statistical analyses of the acceleration capability of gasoline vehicles have focused on zero to 97 km/h acceleration rates and have concluded that peak power per kilogram is an appropriate single surrogate for acceleration capability. In this paper, statistical methods are used with data for 107 vehicles tested and reported by Consumers Union for 1986-1988 model years to estimate the determinants of contemporary gasoline vehicle acceleration capability under various conditions, adding new variables to the statistical tests reported by others. Like previous studies, this analysis determined that power and weight provide the most information about acceleration capability. Using a model formulation unlike other studies, this study found that engine displacement also provides statistically significant improvements in explanation of 0-48, 0-97, and 48-97 km/h acceleration times.

This paper explores the impact of U.S. emission controls and fuel economy improvements on the global warming potential (GWP) of new light-duty vehicles. Fuel economy improvements have reduced the GWP of both passenger cars and light-duty trucks by lowering the per mile emissions of carbon dioxide (CO2). Further GWP reductions have been achieved by emission standards for criteria pollutants: carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). The GWP of a criteria pollutant was calculated by multiplying the emission rate by a relative global warming factor to obtain a CO2 equivalent emission rate. Both CO2 and criteria pollutant emission rates per vehicle have decreased substantially for new light-duty vehicles over the period from 1968 to 1991. Over that period, the GWP from CO2 was reduced by almost 50% in new vehicles by improving fuel economy.

Oxygen-enriched combustion is a proven, seriously considered technique to reduce exhaust hydrocarbons (HC) and carbon monoxide (CO) emissions from automotive gasoline engines. This paper presents the cold-phase emissions reduction results of using oxygen-enriched intake air containing about 23% and 25% oxygen (by volume) in a vehicle powered by a spark-ignition (SI) engine. Both engine-out and converter-out emissions data were collected by following the standard federal test procedure (FTP). Converter-out emissions data were also obtained employing the U.S. Environmental Protection Agency's (EPA's) “Off-Cycle” test. Test results indicate that the engine-out CO emissions during the cold phase (bag 1) were reduced by about 46 and 50%, and HC by about 33 and 43%, using nominal 23 and 25% oxygen enriched air compared to ambient air (21% oxygen by volume), respectively. However, the corresponding oxides of nitrogen (NOx) emissions were increased by about 56 and 79%, respectively.

This paper presents the results of emission tests of a flexible fuel vehicle (FFV) powered by an SI engine, fueled by M85, and supplied with oxygen-enriched intake air containing nominal 21%, 23%, and 25% oxygen (by volume). Emission data were collected by following the standard federal test procedure (FTP) and U.S. Environmental Protection Agency's (EPA's) “off-cycle” test EPA-REP05. Engine-out total hydrocarbons (THCs) and unburned methanol were considerably reduced in the entire FTP cycle when the oxygen content of the intake air was either 23% or 25%. However, CO emissions did not vary appreciably, and NOx emissions were higher. Formaldehyde emissions were reduced by about 53% in bag 1, 84% in bag 2, and 59% in bag 3 of the FTP cycle when 25% oxygen-enriched intake air was used.

The U.S. Department of Energy, through Argonne National Laboratory, and in cooperation with Natural Resources-Canada and Chrysler Canada, sponsored and organized the 1996 Propane Vehicle Challenge (PVC). For this competition, 13 university teams from North America each received a stock Chrysler minivan to be converted to dedicated propane operation while maintaining maximum production feasibility. The converted vehicles were tested for performance (driveability, cold- and hot-start, acceleration, range, and fuel economy) and exhaust emissions. Of the 13 entries for the 1996 PVC, 10 completed all of the events scheduled, including the emissions test. The schools used a variety of fuel-management, fuel-phase and engine-control strategies, but their strategies can be summarized as three main types: liquid fuel-injection, gaseous fuel-injection, and gaseous carburetor. The converted vehicles performed similarly to the gasoline minivan.

Previous work has demonstrated the capabilities of gasoline compression ignition to achieve engine loads as high as 19.5 bar BMEP with a production multi-cylinder diesel engine using gasoline with an anti-knock index (AKI) of 87. In the current study, the low load limit of the engine was investigated using the same engine hardware configurations and 87 AKI fuel that was used to achieve 19.5 bar BMEP. Single injection, “minimum fueling” style injection timing and injection pressure sweeps (where fuel injection quantity was reduced at each engine operating condition until the coefficient of variance of indicated mean effective pressure rose to 3%) found that the 87 AKI test fuel could run under stable combustion conditions down to a load of 1.5 bar BMEP at an injection timing of −30 degrees after top dead center (°aTDC) with reduced injection pressure, but still without the use of intake air heating or uncooled EGR.

This study evaluates iso-butanol as a pathway to introduce higher levels of alternative fuels for recreational marine engine applications compared to ethanol. Butanol, a 4-carbon alcohol, has an energy density closer to gasoline than ethanol. Isobutanol at 16 vol% blend level in gasoline (iB16) exhibits energy content as well as oxygen content identical to E10. Tests with these two blends, as well as indolene as a reference fuel, were conducted on a Mercury 90 HP, 4-stroke outboard engine featuring computer controlled sequential multi-port Electronic Fuel Injection (EFI). The test matrix included full load curves as well as the 5-mode steady-state marine engine test cycle. Analysis of the full load tests suggests that equal full load performance is achieved across the engine speed band regardless of fuel at a 15-20°C increase in exhaust gas temperatures for the alcohol blends compared to indolene.