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Stringent emission standards are driving the development of diesel-fuel injection concepts to mitigate in-cylinder formation of particulates. While research has demonstrated significant reduction in particulate formation using micro-orifice technology, implementation requires development of industrial processes to fabricate micro-orifices with diameters as low as 50 μm and with large length-to-diameter ratios. This paper reviews the different processes being pursued to fabricate micro-orifices and the advanced techniques applied to characterize the performance of micro-orifices. The latter include the use of phase-contrast x-ray imaging of electroless nickel-plated micro-orifices and laser imaging of fuel sprays at elevated pressures. The experimental results demonstrate an industrially viable process to create small uniform orifices that improve spray formation for fuel injection.

Limited battery power and poor engine efficiency at cold temperature results in low plug in hybrid vehicle (PHEV) fuel economy and high emissions. Quick rise of battery temperature is not only important to mitigate lithium plating and thus preserve battery life, but also to increase the battery power limits so as to fully achieve fuel economy savings expected from a PHEV. Likewise, it is also important to raise the engine temperature so as to improve engine efficiency (therefore vehicle fuel economy) and to reduce emissions. One method of increasing the temperature of either component is to maximize their usage at cold temperatures thus increasing cumulative heat generating losses. Since both components supply energy to meet road load demand, maximizing the usage of one component would necessarily mean low usage and slow temperature rise of the other component. Thus, a natural trade-off exists between battery and engine warm-up.

As batteries become a major component of numerous advanced vehicles, significant efforts have been allocated towards characterizing and estimating battery energy capability over the lifetime of a vehicle. Currently, battery State of Charge (SOC) is one of the primary values used for this characterization; however SOC usage has several issues when implemented in Electric Vehicle (EV), Hybrid Electric Vehicle (HEV), and Plug-In Hybrid Electric Vehicle (PHEV) systems. One of the main issues with reporting battery SOC as a characterization of battery energy capability is that it only gives a percentage of the energy available to the operator. SOC does not accurately represent the true capability or capacity of the battery, and thus fails to account for the impact to capability with respect to battery size, age, and recent operational history.

This study undertakes an investigation of the effect of battery charge balance in hybrid electric vehicles (HEVs) on EPA fuel economy label values. EPA's updated method was fully implemented in 2011 and uses equations which weight the contributions of fuel consumption results from multiple dynamometer tests to synthesize city and highway estimates that reflect average U.S. driving patterns. For the US06 and UDDS cycles, the test results used in the computation come from individual phases within the overall certification driving cycles. This methodology causes additional complexities for hybrid vehicles, because although they are required to be charge-balanced over the course of a full drive cycle, they may have net charge or discharge within the individual phases. As a result, the fuel consumption value used in the label value calculation can be skewed.

As vehicle technology progresses to new levels of sophistication, so too, vehicle test methods must evolve. This is true for analytical testing in a laboratory and for on-road vehicle testing. Every year since 1993, the U.S. Department of Energy (DOE) and original equipment manufacturer (OEM) sponsors have organized a series of competitions featuring advanced hybrid electric vehicle (HEV) technology to develop and promote DOE goals in fuel savings and alternative fuel usage. The competition has evolved over many years and has included many alternative fuels feeding the prime mover (including hydrogen fuel cells). EcoCAR turned its focus to plug-in hybrid electric vehicles (PHEVs) and it was quickly realized that to keep using on-road testing methods to evaluate fuel and electricity consumption, a new method needed to be developed that would properly weight depleting operation with the sustaining operation, using the established Utility Factor (UF) method.

The U.S. Department of Energy's Office of Energy Efficiency & Renewable Energy initiated a study that conducted coastdown testing and chassis dynamometer testing of three vehicles, each at multiple test weights, in an effort to determine the impact of a vehicle's mass on road load force and energy consumption. The testing and analysis also investigated the sensitivity of the vehicle's powertrain architecture (i.e., conventional internal combustion powertrain, hybrid electric, or all-electric) on the magnitude of the impact of vehicle mass. The three vehicles used in testing are a 2012 Ford Fusion V6, a 2012 Ford Fusion Hybrid, and a 2011 Nissan Leaf. Testing included coastdown testing on a test track to determine the drag forces and road load at each test weight for each vehicle. Many quality measures were used to ensure only mass variations impact the road load measurements.

The recovery of braking energy through regenerative braking is a key enabler for the improved efficiency of Hybrid Electric Vehicles, Plug-in Hybrid Electric, and Battery Electric Vehicles (HEV, PHEV, BEV). However, this energy is often treated in a simplified fashion, frequently using an overall regeneration efficiency term, ξrg [1], which is then applied to the total available braking energy of a given drive-cycle. In addition to the ability to recapture braking energy typically lost during vehicle deceleration, hybrid and plug-in hybrid vehicles also allow for reduced or zero engine fueling during vehicle decelerations. While regenerative braking is often discussed as an enabler for improved fuel economy, reduced fueling is also an important component of a hybrid vehicle's ability to improve overall fuel economy.

Additive manufacturing was used to fabricate a head for an automotive-scale single-cylinder engine operating on natural gas. The head was consisted of a bimetallic composition of stainless steel and bronze. The engine performance using the bimetallic head was compared against the stock cast iron head. The heads were tested at two speeds (1200 and 1800 rpm), two brake mean effective pressures (6 and 10 bar), and two equivalence ratios (0.7 and 1.0). The bimetallic head showed good durability over the test and produced equivalent efficiencies, exhaust temperatures, and heat rejection to the coolant to the stock head. Higher combustion temperatures and advanced combustion phasing resulted from use with the bimetallic head. The implication is that with optimization of the valve timing, an efficiency benefit may be realized with the bimetallic head.

Gasoline Compression Ignition (GCI) engines using a low octane gasoline-like fuel (LOF) have good potential to achieve lower NOx and lower particulate matter emissions with higher fuel efficiency compared to the modern diesel compression ignition (CI) engines. In this work, we conduct a well-to-wheels (WTW) analysis of the greenhouse gas (GHG) emissions and energy use of the potential LOF GCI vehicle technology. A detailed linear programming (LP) model of the US Petroleum Administration for Defense District Region (PADD) III refinery system - which produces more than 50% of the US refined products - is modified to simulate the production of the LOF in petroleum refineries and provide product-specific energy efficiencies. Results show that the introduction of the LOF production in refineries reduces the throughput of the catalytic reforming unit and thus increases the refinery profit margins.

Given the importance of the fuel-injection process on the combustion and emissions performance of gasoline direct injected engines, there has been significant recent interest in understanding the fluid dynamics within the injector, particularly around the needle and through the nozzles. The pressure losses and transients that occur in the flow passages above the needle are also of interest. Simulations of these injectors typically use the nominal design geometry, which does not always match the production geometry. Computed tomography (CT) using x-ray and neutron sources can be used to obtain the real geometry from production injectors, but there are trade-offs in using these techniques. X-ray CT provides high resolution, but cannot penetrate through the thicker parts of the injector. Neutron CT has excellent penetrating power but lower resolution.

This paper focuses on detailed numerical simulations of direct injection diesel and gasoline sprays from production grade, multi-hole injectors. In a dual-fuel engine the direct injection of both the fuels can facilitate appropriate mixture preparation prior to ignition and combustion. Diesel and gasoline sprays were simulated using high-fidelity Large Eddy Simulations (LES) with the dynamic structure sub-grid scale model. Numerical predictions of liquid penetration, fuel density distribution as well as transverse integrated mass (TIM) at different axial locations versus time were compared against x-ray radiography data obtained from Argonne National Laboratory. A necessary, but often overlooked, criterion of grid-convergence is ensured by using Adaptive Mesh Refinement (AMR) for both diesel and gasoline. Nine different realizations were performed and the effects of random seeds on spray behavior were investigated.

As an energy carrier, hydrogen has the potential to deliver clean and renewable power for transportation. When powered by hydrogen, internal combustion engine technology may offer an attractive alternative to enable the transition to a hydrogen economy. Port-injected hydrogen engines generate extremely low emissions and offer high engine efficiencies if operated in a lean combustion strategy. This paper presents experimental data for different constant air/fuel ratio engine combustion strategies and introduces variable air/fuel ratio strategies for engine control. The paper also discusses the shift strategy to optimize fuel economy and contrasts the different engine control strategies in the conventional vehicle environment. The different strategies are evaluated on the urban driving cycle, then engine behaviors are explained and fuel economy is estimated. Finally, the paper projects the potential of hybridization and discusses trends in powertrain cycle efficiencies.

Preliminary research in our laboratory has demonstrated that boric acid is an effective lubricant with an unusual capacity to reduce the sliding friction (providing friction coefficients as low as 0.02) and wear of metallic and ceramic materials. More recent studies have revealed that water or methanol solutions of boric acid can be used to prepare strongly bonded layers of boric acid on aluminum surfaces. It appears that boric acid molecules have a strong tendency to bond chemically to the naturally oxidized surfaces of aluminum and its alloys and to make these surfaces very slippery. Recent metal-formability tests indicated that the boric acid films applied to aluminum surfaces worked quite well, improving draw scale performance by 58 to 75%.

Current-production hybrid electric vehicles (HEVs) have shown a measurable improvement in fuel economy, in comparison with conventional vehicles, by using the internal combustion engine in a more efficient operating region, which therefore reduces petroleum consumption. These HEVs operate with a charge-sustaining control strategy. Plug-in HEVs (PHEVs) show the potential to further decrease petroleum consumption by operating in a charge-depletion control strategy, in which the energy stored in the battery pack in used during normal driving and recharged through stationary, off-board vehicle charging. This charge-depletion strategy uses more electrical energy to propel the vehicle, which displaces more petroleum. This paper discusses the testing and analysis of a Hymotion Prius PHEV, an Energy CS Prius PHEV, and a Renault Kangoo PHEV.

Hybrid Electric Vehicle (HEV) owners have reported significantly lower fuel economy than the published estimates. Under on-road driving conditions, vehicle acceleration, speed, and stop time differ from those on the normalized test procedures. To explain the sensitivity, several vehicles, both conventional and hybrid electric, were tested at Argonne National Laboratory. The tests demonstrated that the fuel economy of Prius MY04 was more sensitive to drive-cycle variations. However, because of the difficulty in instrumenting every component, an in-depth analysis and quantification of the reasons behind the higher sensitivity was not possible. In this paper, we will use validated models of the tested vehicles and reproduce the trends observed during testing. Using PSAT, the FreedomCAR vehicle simulation tool, we will quantify the impact of the main component parameters, including component efficiency and regenerative braking.

Developed by the U.S. Environmental Protection Agency (EPA), the Multi-scale mOtor Vehicle Emission Simulator (MOVES) is used to estimate inventories and projections through 2050 at the county or national level for energy consumption, nitrous oxide (N2O), and methane (CH4) from highway vehicles. To simulate a large number of vehicles and fleets on numerous driving cycles, EPA developed a binning technique characterizing the energy rate for varying Vehicle Specific Power (VSP) under predefined vehicle speed ranges. The methodology is based upon the assumption that the vehicle behaves the same way for a predefined vehicle speed and power demand. While this has been validated for conventional vehicles, it has not been for advanced vehicle powertrains, including hybrid electric vehicles (HEVs) where the engine can be ON or OFF depending upon the battery State-of-Charge (SOC).

Their high fuel economy is making light-duty vehicles with spark-ignition direct-injection (SIDI) engines attractive. However, the implications for exhaust emissions and the effects of fuel quality on emissions are not clear for this type of engine. A Mitsubishi Legnum with a 1.8-L GDI™ engine was tested on federal test procedure (FTP) and highway fuel economy cycles. The results were compared with those for a production Dodge Neon vehicle with a 2.0-L port fuel-injection (PFI) engine. The Mitsubishi was tested with Indolene, Amoco Premium Ultimate, and a low-sulfur gasoline. The Neon was tested only with Indolene. Both engine-out and tailpipe emissions were measured. Second-by-second emissions and hydrocarbon speciation were also evaluated. The SIDI engine provided up to 24% better fuel economy than the PFI engine on the highway cycle. Tailpipe emissions of oxides of nitrogen (NOx) from the SIDI vehicle using low-sulfur fuel were 40% less than those when using Indolene.

Fuel cell vehicles are undergoing extensive research and development because of their potential for high efficiency and low emissions. Because fuel cell vehicles remain expensive and there is limited demand for hydrogen at present, very few fueling stations are being built. To try to accelerate the development of a hydrogen economy, some original equipment manufacturers in the automotive industry have been working on a hydrogen-fueled internal combustion engine (ICE) as an intermediate step. This paper compares the fuel economy potential of hydrogen powertrains to conventional gasoline vehicles. Several timeframes are considered: 2010, 2015, 2030, and 2045. To address the technology status uncertainty, a triangular distribution approach was implemented for each component technology. The fuel consumption and cost of five powertrain configurations will be discussed and compared with the conventional counterpart.

Plug-in Hybrid Electric Vehicles (PHEVs) use electric energy from the grid rather than fuel energy for most short trips, therefore drastically reducing fuel consumption. Different configurations can be used for PHEVs. In this study, the parallel pre-transmission, series, and power-split configurations were compared by using global optimization. The latter allows a fair comparison among different powertrains. Each vehicle was operated optimally to ensure that the results would not be biased by non-optimally tuned or designed controllers. All vehicles were sized to have a similar all-electric range (AER), performance, and towing capacity. Several driving cycles and distances were used. The advantages of each powertrain are discussed.

Previous studies and on-road driving by consumers have shown that Hybrid Electric Vehicle fuel economy is very dependent on driver demand in both vehicle speed and vehicle acceleration [1]. The emerging technology of Plug-In Hybrid Vehicles (PHEV) may prove to also be more sensitivity to aggressive driver demand as compared to conventional internal combustion engine vehicles. This is due to the exceptional ability of the PHEV to minimize fuel consumption at mid to low power levels by the significant use of electric propulsion which enables engine downsizing. As vehicle speed and acceleration increase so does the power demand on the powertrain. The fuel consumption is directly affected by this increase in power demand level. To examine the fuel consumption impact of changing driver characteristics on PHEV’s, testing is conducted on two vehicles (parallel PHEV and power-split PHEV) on a four wheel chassis dynamometer at Argonne’s Advanced Powertrain Research Facility.