The question of whether increasing the fuel economy of light-duty natural gas fueled vehicles can improve their economic competitiveness in the U.S. market, and help the US Department of Energy meet stated goals for such vehicles is explored. Key trade-offs concerning costs, exhaust emissions and other issues are presented for a number of possible advanced engine designs. Projections of fuel economy improvements for a wide range of lean-burn engine technologies have been developed. It appears that compression ignition technologies can give the best potential fuel economy, but are less competitive for light-duty vehicles due to high engine cost. Lean-burn spark ignition technologies are more applicable to light-duty vehicles due to lower overall cost. Meeting Ultra-Low Emission Vehicle standards with efficient lean-burn natural gas engines is a key challenge.
In this study, feasibility tests of secondary air injection technology and lean A/F control technology were performed for LEV program using the FTP75 test on a 2.0 DOHC A/T vehicle. Second-by-second emissions and temperatures were evaluated. The temperatures of exhaust gas were measured at exhaust manifold, front of warm up, and the center of warm up converter. At first, amount of secondary air injection was determined with a bench aged warm up converter and a fresh UCC. And then, the performances of secondary air injection and lean A/F control strategy were compared with 80,000km vehicle aged converters(warm up converter, UCC). Both secondary air injection and lean A/F control technologies satisfied the ULEV regulation. This study shows that the lean A/F control strategy can be one of the potential technologies to meet the LEV/ULEV regulations without an active system that need a cost up.
The Coordinating Research Council conducted a program to measure the reversibility of fuel sulfur effects on emissions from California Low Emission Vehicles (LEVs). Six LEV models were tested using two non-oxygenated conventional Federal fuels with 30 and 630 ppm sulfur. The following emission test sequence was used: 30 ppm fuel to establish a baseline, 630 ppm fuel, and return to 30 ppm fuel. A series of emission tests were run after return to 30 ppm to ensure that emissions had stabilized. The effect of the driving cycle on reversibility was evaluated by using both the LA4 and US06 driving cycles for mileage accumulation between emission tests after return to 30-ppm sulfur fuel. The reversibility of sulfur effects was dependent on the vehicle, driving cycle, and the pollutant. For the test fleet as a whole most but not all of the sulfur effects were reversible.
The requirement to meet more stringent emission standards has focused attention on the effects of gasoline sulfur on automotive emissions. Numerous studies have shown that three-way catalyst performance is severely inhibited by sulfur. A literature review of laboratory studies on the interaction of sulfur with automotive catalyst components provides the basis for understanding impacts on catalyst activity under the variety of conditions encountered in vehicle operation. Under stoichiometric and rich conditions, SO2 formed during combustion is dissociatively adsorbed on platinum group metal surfaces to form strongly bound Sad. Sulfur inhibition results from both physical blockage and electronic effects of Sad, such that low coverage of Sad results in disproportionately higher levels of reaction site blockage. This is responsible for the nonlinear effects observed with increasing fuel sulfur level.
The natural gas vehicle has high potential as an Environmentally Enhanced Vehicle (EEV). In order to achieve low-emissions, a precise gaseous injection system coupled with optimized feedback control is necessary for the natural gas engines. An advanced natural gas vehicle, such as the Honda Civic GX, can meet the Super-Ultra-Low-Emission Vehicle (SULEV) emission standard in California and also meet the future European & Japanese emission standards. The low-emission natural gas vehicle emits very low off-cycle emissions, air toxic emissions and has zero-fuel evaporative emissions. The use of natural gas-based fuels achieves CO2 emission reductions relative to use of petroleum-based fuels. Low-emission NGVs are attractive for use in urban and metropolitan city centers to reduce smog.
The aerodynamic drag of future low emission vehicles will need to be low. Unfortunately, vehicle shapes that result in low drag coefficients - of the order of 0.15 - are often aerodynamically unstable in crosswinds. The addition of wheels, transmission, radiators, suspension, steering, brakes, air ducts and wing mirrors can easily increase this drag coefficient to 0.24 and above and produce an undesirable lift distribution. The Aero-Stable Carbon Car (ASCC) is a research project, in conjunction with industrial partners, to design and build a practical 3 to 4 seat low drag car (CD less than 0.20) with an acceptable lift distribution (front to rear) which is also stable in crosswinds and in yaw through a series of low speed wind tunnel tests performed in the Cranfield College of Aeronautics 8′ × 6′ wind tunnel facility.
A new gasoline-fueled Super Ultra Low Emissions Vehicle (SULEV) technology has been developed that meets the California Air Resources Board's (CARB) most stringent tailpipe emission levels and zero evaporative emissions, while fulfilling all On-Board Diagnostic II (OBD II) requirements. This paper will describe the various new technologies used in achieving the SULEV standards, such as the HC trap system with an ultra-thin wall substrate for the improvement of catalyst light-off time, and an electrically actuated swirl control valve for reducing cold-start emissions. In addition, a control approach to stabilizing NOx emissions will also be discussed.
In this study, a chemiluminescence apparatus (CL), ATLAS CL–400, was employed to measure the oxidation induction time (OIT) of various types of lubricants. Results of OIT obtained for base oils and industrial oils were compared to that obtained from standardized methods requiring larger expenditures of sample and/or analysis time. Some exploratory tests were also run on engine oils having increased expected performance. The technique was found to be very good for the ranking of lubricants since the relative oxidation stability of the products studied has been successfully evaluated by chemiluminescence (CL). This method was shown to be a good tool for oil formulation optimization.
Classical approaches to pollution control have been to develop benign, non-polluting processes or to abate emissions at the tailpipe or stack before release to the atmosphere. A new technology called PremAir® Catalyst Systems1 takes a different approach and reduces ambient, ground level ozone directly. This technology takes advantage of the huge volumes of air which are processed daily by both mobile and stationary heat exchange devices. For mobile applications, the new system involves placing a catalytic coating on a vehicle's radiator or air conditioning condenser. For stationary applications, the catalytic coating typically is applied to an insert, which is attached to the air conditioning condenser. In either case, the catalyst converts ozone to oxygen as ozone containing ambient air passes over the coated radiator or condenser surfaces.
The emissions impact associated with increasing gasoline sulfur content was investigated using eight late-model vehicles, most of which were equipped with advanced emission control systems and certified as California Low-Emission Vehicles. The effect of returning to operation on low-sulfur fuel on emissions was also investigated. Vehicle testing was performed using California Phase 2 Certification test fuels with nominal sulfur levels of 40 and 540 ppm in combination with the LA4 and US06 driving cycles. In addition to exhaust emission measurements, engine-out emissions, air-fuel ratio, catalyst composition, and catalyst temperature data were collected. The data showed that most of the vehicles were sensitive to gasoline sulfur content as emissions increased when the vehicles were operated on the higher-sulfur test fuel; however, the degree of sensitivity varied from vehicle to vehicle.
The College of Engineering-Center for Environmental Research and Technology at the University of California, Riverside and Honda Motor Company are conducting a cooperative research program to study the emission characteristics and evaluate the environmental impact of advanced technology vehicles designed to have emission rates at, or below, the California ULEV standard. This program involves a number of technical challenges relating to instrumentation capable of measuring emissions at these low levels and utilizing this instrumentation to gather data under realistic conditions that will allow assessments of the environmental impact of these advanced vehicle technologies. This paper presents results on the performance and suitability of a Fourier Transform Infrared (FTIR) based on-board measurement system developed principally by Honda R&D for this task. This system has been designed to simultaneously measure vehicle exhaust and ambient roadway pollutant concentrations.
The new California LEV-II regulations for “near zero” evaporative emissions require a 75% reduction from current emission levels for light duty vehicles. To meet the challenge of satisfying these new regulations, there is an immediate need for an increased understanding of the sources of evaporative emissions. Hydrocarbon speciation by gas chromatography is a powerful analytical tool for determining the composition of complex hydrocarbon mixtures. Gas chromatography and gas chromatography/mass spectrometry were used to identify the volatile organic compounds (VOC) present in the evaporative emissions from a number of prototype and recent production model gasoline-fueled vehicles. For a “typical” evaporative emissions sample, more than 90% of the emissions were found to be fuel-type hydrocarbons.
Measuring the real-world performance of emission control technologies is an important aspect in the development of advanced low-emission vehicles. In addition, data acquired from such measurements can be used to improve the accuracy of air quality predictive models. Honda has developed an on-board sampling/analysis system capable of measuring on-road emissions at ULEV levels and below. Ambient air can be analyzed simultaneously. This FTIR-based system can measure several species; this paper will focus on NMHC, NOX, and CO. Techniques were developed to address the challenges associated with acquiring accurate real-time data at concentrations below 1 ppm in an on-road vehicle. Validation studies performed with reference gases and vehicle exhaust indicate a very good correlation between the on-road analyzer system and classic bench methods for all target compounds. Dynamic studies performed by the University of California, Riverside, also show good correlation.
Tomorrow's winning powertrain solutions reside in those technology combinations providing optimized propulsion systems with zero emissions and no cost or performance penalty compared with today's vehicles. The recent Kyoto Protocol for CO2 reduction and the California Air Resources Board (CARB) thrust for zero emission vehicles along with the European Regulatory community, motivate car manufacturers to adopt new light body structures with low aerodynamic drag coefficients, low-rolling resistance and the highest efficiency powertrains. The environmental equation expresses car manufacturers aptitude and desire to create zero emission vehicles at acceptable levels of performance unlike limited range electrical powered vehicle products. The cheapest solution to the environmental equation remains the conventional internal combustion engine ($30 to $50 per kW).
The effects of gasoline fuel properties on exhaust emissions were investigated. Port injection LEVs, a ULEV, a prototype SULEV which were equipped with three–way (3–way) catalysts and also two vehicles with direct injection spark ignition (DISI) engines equipped with NOx storage reduction (NSR) catalysts were tested. Fuel sulfur showed a large effect on exhaust emissions in all the systems. In the case of the DISI engine with the NSR catalyst, NOx conversion efficiency and also regeneration from sulfur poisoning were dramatically improved by reducing sulfur from 30ppm to 8ppm. Distillation properties also affected the HC emissions significantly. The HC emissions increased in both the LEV and the ULEV with a driveability index (DI) higher than about 1150 (deg.F). The ULEV was more sensitive than the LEV. These results show that fuel properties will be important for future technologies required to meet stringent emission regulations.
With the advent of low evaporative emission requirements there has been the rapid adoption of multilayer extrusion technology into the production of Fuel and Vapour tubing used on Fuel systems on automobiles. Multilayer extrusion technology enables a manufacturer of Fuel and Vapour tubing to simultaneously co-extrude dissimilar thermoplastic materials in tubular form. This allows the manufacturer to combine expensive and brittle high performance evaporative emission ‘barrier’ polymers with lower cost engineering polymers. However, it is a well-known characteristic of these multilayer tube constructions that the joints between them and connector ‘barbs’ have lower joint integrity. Joint integrity is most often quantified by ‘Pull-off’ and leakage tests. Recent developments in LEV-II requirements for 2004 and beyond indicate that joint integrity will become a focus area for study and improvement.
This paper describes the history of promotional activities in Japan for neat methanol fuel (M100) vehicles. Since the middle of the 1980s, Nippon Methanol Fueled Vehicles Co., Ltd. (now, Organization for the Promotion of Low Emission Vehicles (LEVO)), has been leasing M100 vehicles, and has conducted research work regarding these vehicles. LEVO has also been involved in infrastructure promotion for M100 vehicles, to ensure energy security and as a countermeasure against air pollution. As a result, as of March 1999, a total of 572 M100 vehicles had been leased to fleet operators. This more than 10 years of market experience with these vehicles has contributed toward convincing the Japanese Government, local governments and fleet operators of methanol's potential as an automotive fuel.
This paper describes work done on spark-ignition engine Downsizing and Super-Charging (DSC). Substantial DSC is shown to have a potential for good fuel-economy in SI-engines especially at part-load without compromising in pollutant emission levels. Built into a 4-passenger light-weight car a fuel economy of 67 M/gal (3.5 l/100km) in the European test cycle MVEG-95 was achieved with the potential to satisfy ULEV or Euro IV emission limits.