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Particulate and nitrogen oxide emissions from a 1.9-liter Volkswagen diesel engine were measured for three different fuels: neat diesel fuel, a blend of diesel fuel with 10% ethanol, and a blend of diesel fuel with 15% ethanol. Engine-out emissions were measured on an engine dynamometer for five different speeds and five different torques using the standard engine-control unit. Results show that particulate emissions can be significantly reduced over approximately two-thirds of the engine map by using a diesel-ethanol blend. Nitrogen oxide emissions can also be significantly reduced over a smaller portion of the engine map by using a diesel-ethanol blend. Moreover, there is an overlap between the regions where particulate emissions can be reduced by up to 75% and nitrogen oxide emissions are reduced by up to 84% compared with neat diesel fuel.

The Prius is a major achievement by Toyota: it is the first mass-produced HEV with the first available HEV-optimized engine. Argonne National Laboratory's Advanced Powertrain Test Facility has been testing the Prius for model validation and technology performance and assessment. A significant part of the Prius test program is focused on testing and mapping the engine. A short-length torque sensor was installed in the powertrain in-situ. The torque sensor data allow insight into vehicle operational strategy, engine utilization, engine efficiency, and specific emissions. This paper describes the design and process necessary to install a torque sensor in a vehicle and shows the high-fidelity data measured during chassis dynamometer testing. The engine was found to have a maximum thermodynamic efficiency of 36.4%. Emissions and catalyst efficiency maps were also produced.

The effects of hybridization on heavy-duty vehicles are not well understood. Heavy vehicles represent a broader range of applications than light-duty vehicles, resulting in a wide variety of chassis and engine combinations, as well as diverse driving conditions. Thus, the strategies, incremental costs, and energy/emission benefits associated with hybridizing heavy vehicles could differ significantly from those for passenger cars. Using a modal energy and emissions model, we quantify the potential energy savings of hybridizing commercial Class 3-7 heavy vehicles, analyze hybrid configuration scenarios, and estimate the associated investment cost and payback time.

The effects of nitrogen-enriched air, supplied by an air separation membrane, on NOx emissions from a 1.9-L turbocharged direct-injection diesel engine were investigated. To enrich combustion air with more nitrogen, prototype air separation membranes were installed between the after-cooler and intake manifold without any additional controls. The effects of nitrogen-enriched combustion air on NOx emissions were compared with and without exhaust gas recirculation (EGR). At sufficient boost pressures (>50 kPag), nitrogen-enriched air from the membrane provided intake oxygen levels that were similar to those of EGR. Compared with EGR, nitrogen-enriched air provided 10-15% NOx reductions during medium to high engine loads and speeds. At part loads, when turbocharger boost pressure was low, the air separation membrane was not effective in enriching air with nitrogen. As a result, NOx reduction was lower, but it was 15-25% better than when EGR was not used.

Droplet vaporization models that are currently employed in simulating diesel engine sprays are based on a quasi-steady, low-pressure formulation. This formulation does not adequately represent many high-pressure effects, such as non-ideal gas behavior, solubility of gases into liquid, pressure dependence of liquid- and gas-phase thermophysical properties, and transient liquid transport in the droplet interior. More importantly, the quasi-steady assumption becomes increasingly questionable as the ambient pressure approaches and /or exceeds the fuel critical pressure. In the present study, a high-pressure, quasi-steady vaporization model is developed. Except for the quasi-steady assumption that is retained in the model, it incorporates all the other high-pressure effects.

A 1998 Toyota Corona passenger car with a direct injection spark ignition (DISI) engine was tested at constant engine speed (2000 rpm) over a range of loads. Engine-out and tailpipe emissions of gas phase species were measured each second. This allowed examination of the engine-out emissions for late and early injection. Regeneration of the lean NOx trap/catalyst was also examined, as was the efficiency of NOx reduction. NOx stored in the trap/catalyst is released at the leading edge of regenerations, such that the tailpipe NOx is higher than the engine-out NOx for a brief period. The efficiency of NOx reduction was <50% for the lowest loads examined. As the load increased, the efficiency of NOx reduction decreased to near 0% due to excessive catalyst temperatures. Loads sufficiently high to require a rich mixture produce high NOx reduction efficiencies, but in this case the NOx reduction occurs via the three-way catalysts on this vehicle.

A 1998 Toyota Corona passenger car with a direct injection spark ignition (DISI) engine was tested via a variety of driving cycles using California Phase 2 reformulated gasoline. A comparable PFI vehicle was also evaluated. The standard driving cycles examined were the Federal Test Procedure (FTP), Highway Fuel Economy Test, US06, simulated SC03, Japanese 10-15, New York City Cycle, and European ECE+EDU. Engine-out and tailpipe emissions of gas phase species were measured each second. Hydrocarbon speciations were performed for each phase of the FTP for both the engine-out and tailpipe emissions. Tailpipe particulate mass emissions were also measured. The results are analyzed to identify the emissions challenges facing the DISI engine and the factors that contribute to the particulates, NOx, and hydrocarbon emissions problems of the DISI engine.

Particulate and gaseous emissions from a Mitsubishi Legnum GDI™ wagon were measured for FTP-75, HWFET, SC03, and US06 cycles. The vehicle has a 1.8-L spark-ignition direct-injection engine. Such an engine is considered a potential alternative to the compression-ignition direct-injection engine for the PNGV program. Both engine-out and tailpipe emissions were measured. The fuels used were Phase-2 reformulated gasoline and Indolene. In addition to the emissions, exhaust oxygen content and exhaust-gas temperature at the converter inlet were measured. Results show that the particulate emissions are measurable and are significantly affected by the type of fuel used and the presence of an oxidation catalyst. Whether the vehicle can meet the PNGV goal of 0.01 g/mi for particulates depends on the type of fuel used. Both NMHC and NOx emissions exceed the PNGV goals of 0.125 g/mi and 0.2 g/mi, respectively. Meeting the NOx goal will be especially challenging.

Recent advances in fuel-cell technology and low-emission, direct-injection spark-ignition and diesel engines for vehicles could significantly change the transportation vehicle power plant landscape in the next decade or so. This paper is a scoping study that compares total fuel cycle options for providing power to personal transport vehicles. The key question asked is, “How much of the energy from the fuel feedstock is available for motive power?” Emissions of selected criteria pollutants and greenhouse gases are qualitatively discussed. This analysis illustrates the differences among options; it is not intended to be exhaustive. Cases considered are hydrogen fuel from methane and from iso-octane in generic proton-exchange membrane (PEM) fuel-cell vehicles, methane and iso-octane in spark-ignition (SI) engine vehicles, and diesel fuel (from methane or petroleum) in direct-injection (DI) diesel engine vehicles.

This paper evaluates the total lifecycle impacts for hauling freight long distances over land in the United States. The dominant modes of surface freight transport in the United States are large motor trucks (tractor-semitrailer combinations) and trains. These vehicles account for a significant portion of the transportation sector's petroleum usage and atmospheric emissions (among which nitrogen oxides and particulate matter are especially important). The objective of this paper is to evaluate the potential for reductions in energy use (in particular, petroleum use) and atmospheric emissions that result from freight transport, possibly as the result of research and development on improved technology or alternative fuels, such as Fischer-Tropsch diesel and natural gas, or from mode shifts in competitive markets. The impacts examined include energy use, both in toto and the petroleum fraction, and emissions of greenhouse gases and nitrogen oxides and particulate matter.

A two-stage Delphi study was conducted to collect information that would enable a technical and economic assessment of electric (EV) and hybrid electric (HEV) vehicles. The first-stage worldwide survey was completed in fall 1994 while the second-stage was completed by summer 1995. The paper reports results from the second round of the survey and the major differences between the two rounds. This second-stage international survey obtained information from 93 expert respondents from the automotive technology field. The second stage response provided the following key results. EVs will penetrate the market first followed by internal combustion engine powered HEVs while gas turbine and fuel cell powered HEVs will not have any significant penetration until after 2020. By 2020 EVs and internal combustion engine powered HEVs are projected to have approximately a 15% share of the new vehicle market.

An optically-accessible single-cylinder compression-ignition two-stroke research engine equipped with dual-injection system, image acquisition, and control system have been designed to acquire two-dimensional images of the pilot and main diesel fuel sprays. The engine construction permits illumination of the sprays by a thin sheet of laser light from a pulsed Nd:YAG laser frequency tripled to operate at the ultraviolet wavelength of 355 nm. The liquid fuel was decane with TMPD-naphthalene dopant dispersed in it. Upon ultraviolet excitation by the pulsed laser, liquid fuel regions fluoresced with a spectrum centered at the wavelength of 380 nm, while vapor regions fluoresced with a spectrum centered at 470 nm. This approach, called Exciplex technique, was applied to permit simultaneous acquisition of the liquid and vapor fuel regions in the cup-in- head geometry of the combustion chamber.

An optically-accessible research engine, image acquisition, and a control system are designed to acquire two-dimensional images of a pilot and main Diesel fuel sprays. This paper presents the engine-based apparatus, image acquisition techniques, and preliminary results of analysis performed upon interacting Diesel fuel sprays. The engine is a single-cylinder compression-ignition two-stroke with optically-accessible head mounted on a high speed CFR engine crankcase. It is equipped with a special dual-injection system for production of in-cylinder interacting sprays (main and pilot) with a high degree of adjustability with regard to the sprays fuel quantities and injection timings. The engine construction permits illumination of the sprays by a thin sheet of laser light from a pulsed Nd:YAG laser frequency doubled to operate at the visible wavelength of 532 nm.

The net heat release rate and net heat release fraction for a spark-ignited (SI) single-cylinder two-stroke, production engine were analyzed using the one-zone model. Three different throttle positions and four engine speeds for each position were considered for this study. The method used required cylinder pressure and crank-angle data which were obtained from a pressure transducer mounted in the cylinder head and a shaft encoder connected to the crankshaft. An effective routine referred to as the overlap method was used to smooth undesirable oscillations on the heat release rate curves after investigation of several different approaches. Parameters such as maximum heat release rate, rapid burn angle, combustion duration, maximum heat release rate angle, imep, bmep, etc. were calculated and discussed.

To better understand the complex scavenging process in ported two-stroke engines, velocity measurements were taken at the exit of an intake port of a motoring and firing single-cylinder propane-fueled two-stroke engine by Laser Doppler Velocimetry (LDV). The radial velocity component was measured at the center of one port at engine speeds of 600, 900, and 1200 rpm. Cylinder pressure was also recorded for both motoring and firing cycles. When plotted versus crankangle, it was observed that the intake flow ensemble-averaged mean velocities have a characteristic two-end-peak profile with peaks occurring just after the piston exposes or is about to block the measurement volume. The two peaks occurred at approximately the same crankangle in both the motoring and firing engines. At 600 rpm the two velocity end peaks in the fired engine are larger than the corresponding motored values by a factor of 1.73 to 2.26.

Analytical studies of oxygen-enriched diesel engine combustion have indicated the various benefits as well as the need for using cheaper fuels with water addition. To verify analytical results, a series of single-cylinder diesel engine tests were conducted to investigate the concepts of oxygen enriched air (OEA) for combustion with water emulsified fuels. Cylinder pressure traces were obtained for inlet oxygen levels of 21% to 35% and fuel emulsions with water contents of 0% to 20%. Data for emulsified fuels included no. 2 and no. 4 diesel fuels. The excess oxygen for the tests was supplied from compressed bottled oxygen connected to the intake manifold. The cylinder pressure data was collected with an AVL pressure transducer and a personal computer-based data logging system. The crank angle was measured with an optical encoder. In each data run, 30 consecutive cycles were recorded and later averaged for analysis.