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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.

Dual-fuel combustion using liquid fuels with differing reactivity has been shown to achieve low-temperature combustion with moderate peak pressure rise rates, low soot and NOx emissions, and high indicated efficiency. Varying fractions of gasoline-type and diesel-type fuels enable operation across a range of low- and mid-load operating conditions. Expanding the operating range to cover the full operating range of a heavy-duty diesel engine, while maintaining the efficiency and emissions benefits, is a key objective. With dissimilar properties of the two utilized fuels lying at the heart of the dual-fuel concept, a tool for enabling this load range expansion is altering the properties of the two test fuels - this study focuses on altering the reactivity of the diesel fuel component. Tests were conducted on a 13L six-cylinder heavy-duty diesel engine modified to run dual-fuel combustion with port gasoline injection to supplement the direct diesel injection.

A new method is proposed for controlling the temperature of high-temperature batteries namely, varying the hydrogen pressure inside of multifoil insulation by varying the temperature of a reversible hydrogen getter. Calculations showed that the rate of heat loss through 1.5 cm of multifoil insulation between a hot-side temperature of 425°C and a cold-side temperature of 25°C could be varied between 17.6 W/m2 and 7,000 W/m2. This change in heat transfer rate can be achieved by varying the hydrogen pressure between 1.0 Pa and 1000 Pa, which can be done with an available hydrogen gettering alloy operating in the range of 50°C to 250°C. This approach to battery cooling requires cylindrical insulating jackets, which are best suited for bipolar batteries having round cells approximately 10 to 18 cm in diameter.

A test series was conducted on a six-cylinder diesel engine to study the impacts of controlled factors (i.e., oxygen content of the combustion air, water content of the fuel, fuel-flow rate, and fuel-injection timing) on engine performance and emissions using Taguchi techniques. Separate experiments were conducted using a commercial-grade No. 2-diesel and a lower-grade No. 6-diesel fuel. This paper reports the test results for No. 6 fuel. Oxygen enrichment improved the combustion process with the lower-grade fuel. There was no observable change in turbocharger performance due to oxygen enrichment. The results showed significant reductions in smoke and particulate emissions, a small increase in thermal efficiency and a large increase in NOx emissions when oxygen-enriched air was used. The effect of water-emulsified fuel on NOx emissions was negligible.

A hybrid bus powered by a diesel engine and a battery pack has been analyzed over an idealized bus-driving cycle in Chicago. Three hybrid configurations, two parallel and one series, have been evaluated. The results indicate that the fuel economy of a hybrid bus, taking into account the regenerative braking, is comparable with that of a conventional diesel bus. Life-cycle costs are slightly higher because of the added weight and cost of the battery.

Advanced battery technology evaluations are performed under simulated electric-vehicle operating conditions at the Analysis & Diagnostic Laboratory (ADL) of Argonne National Laboratory. The ADL results provide insight into those factors that limit battery performance and life. The ADL facilities include a test laboratory to conduct battery experimental evaluations under simulated application conditions and a post-test analysis laboratory to determine, in a protected atmosphere if needed, component compositional changes and failure mechanisms. This paper summarizes the performance characterizations and life evaluations conducted during 1991 - 1992 on both single cells and multi-cell modules that encompass eight battery technologies [Na/S, Li/MS (M=metal), Ni/MH, Ni/Cd, Ni/Zn, Ni/Fe, Zn/Br, and Pb-acid]. These evaluations were performed for the Department of Energy, Office of Transportation Technologies, Electric and Hybrid Propulsion Division, and the Electric Power Research Institute.

The U.S. Department of Energy sponsored several student engineering competitions in 1993 that provided useful information on electric and hybrid electric vehicles. The electrical energy usage from these competitions has been recorded with a custom-built digital meter installed in every vehicle and used under controlled conditions. When combined with other factors, such as vehicle mass, speed, distance traveled, battery type, and type of components, this information provides useful insight into the performance characteristics of electrics and hybrids. All the vehicles tested were either electric vehicles or hybrid vehicles in electric-only mode, and had an average energy economy of 7.0 km/kWh. Based on the performance of the “ground-up” hybrid electric vehicles in the 1993 Hybrid Electric Vehicle Challenge, data revealed a 1 km/kWh energy economy benefit for every 133 kg decrease in vehicle mass.

The U.S. Department of Energy (DOE) through Argonne National Laboratory sponsored and recorded energy data of electric vehicles (EVs) at five competitions in 1994. Each competition provided different test conditions (closed-track, on-road, and dynamometer). The data gathered at these competitions includes energy efficiency, range, acceleration, and vehicle characteristics. The results of the analysis show that the vehicles performed as expected. Some of the EVs were also tested on dynamometers and compared to gasoline vehicles, including production vehicles with advanced battery systems. Although the EVs performed well at these competitions, the results show that only the vehicles with advanced technologies perform as well or better than conventional gasoline vehicles.

As a life-cycle analysis tool, MARVEL has been developed for the evaluation of hybrid/electric vehicle systems. It can identify the optimal combination of battery and heat engine characteristics for different vehicle types and performance requirements, on the basis of either life-cycle cost or fuel efficiency. Battery models that allow trade-offs between specific power and specific energy, between cycle life and depth of discharge, between peak power and depth of discharge, and between other parameters, are included in the software. A parallel hybrid configuration, using an internal combustion engine and a battery as the power sources, can be simulated with a user-specified energy management strategy. The PC-based software package can also be used for cost or fuel efficiency comparisons among conventional, electric, and hybrid vehicles.

Electric vehicle batteries use energy and generate environmental residuals when they are produced and recycled. This study estimates, for four selected battery types (advanced lead-acid, sodium-sulfur, nickel-cadmium, and nickel-metal hydride), the impacts of production and recycling of the materials used in electric vehicle batteries. These impacts are compared, with special attention to the locations of the emissions. It is found that the choice among batteries for electric vehicles involves tradeoffs among impacts. For example, although the nickel-cadmium and nickel-metal hydride batteries are similar, energy requirements for production of the cadmium electrodes may be higher than those for the metal hydride electrodes, but the latter may be more difficult to recycle.

In the 1995 HEV Challenge competition, 17 prototype Hybrid Electric Vehicles (HEVs) were tested by using special HEV test procedures. The contribution of the batteries during the test, as measured by changes in battery state-of-charge (SOC), were accounted for by applying SOC corrections to the test data acquired from the results of the HEV test. The details of SOC corrections are described and two different HEV test methods are explained. The results of the HEV test methods are explained. The results of the HEV tests and the effects on the test outcome of varying HEV designs and control strategies are examined. Although many teams had technical problems with their vehicles, a few vehicles demonstrated high fuel economy and low emissions. One vehicle had emissions lower than California's ultra-low emission vehicle (ULEV) emissions rates, and two vehicles demonstrated higher fuel economy and better acceleration than their stock counterparts.

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.

Global Sensitivity Analysis (GSA) is conducted for a diesel engine simulation to understand the sensitivities of various modeling constants and boundary conditions in a global manner with regards to multi-target functions such as liquid length, ignition delays, combustion phasing, and emissions. The traditional local sensitivity analysis approach, which involves sequential perturbation of model constants, does not provide a complete picture since all the parameters can be uncertain. However, this approach has been studied extensively and is advantageous from a computational point of view. The GSA simultaneously incorporates the uncertainty information for all the relevant boundary conditions, modeling constants, and other simulation parameters. A global analysis is particularly useful to address the important parameters in a model where the response of the targets to the values of the variables is highly non-linear.

The use of gasoline in a compression ignition engine has been a research focus lately due to the ability of gasoline to provide more premixing, resulting in controlled emissions of the nitrogen oxides [NOx] and particulate matter. The present study assesses the reactivity of 93 RON [87AKI] gasoline in a GM 1.9L 4-cylinder diesel engine, to extend the low load limit. A single injection strategy was used in available experiments where the injection timing was varied from −42 to −9 deg ATDC, with a step-size of 3 deg. The minimum fueling level was defined in the experiments such that the coefficient of variance [COV] of indicated mean effective pressure [IMEP] was less than 3%. The study revealed that injection at −27 deg ATDC allowed a minimum load of 2 bar BMEP. Also, advancement in the start of injection [SOI] timing in the experiments caused an earlier CA50, which became retarded with further advancement in SOI timing.