Search Results

Due to environmental and legislative concerns, less polluting and more efficient vehicle powertrain systems must be developed. A first step is a simple, low cost system such as the presented Engine Stop-Start (ESS) system. A 1.9 liter four-cylinder spark-ignition engine with a four-speed automatic transmission was modified to enable fuel off-on transitions during decelerations and stops. Additional hardware includes a 7 kW electric motor-generator, a power electronics module with an inverter and a DCDC converter, a 36 Volt nominal battery system, and minor modifications to the transmission. A control scheme was developed which takes advantage of the system's fuel saving potential while minimally affecting driveability. Tests have shown EPA City fuel economy gains of approximately 12-14 percent while maintaining the same emissions classification. The EPA Highway fuel economy was increased by approximately 1 percent.

The design of the newly developed Toyota AZ series 4 cylinder engine has been optimized through both simulations and experiments to improve heat transfer, cooling water flow, vibration noise and other characteristics. The AZ engine was developed to achieve good power performance and significantly reduced vibration noise. The new engine meets the LEV regulations due to the improved combustion and optimized exhaust gas flow. A major reduction in friction has resulted in a significant improvement in fuel economy compared with conventional models. It also pioneered a newly developed resin gear drive balance shaft.

Global environmental issues require that new alternatives to R-134a refrigerant be investigated by the automotive air-conditioning (A/C) industry. Test facilities must be able to handle the challenges that these refrigerants pose. One refrigerant currently under investigation is Carbon Dioxide (CO2). The high pressure and toxicity of CO2, require the test facility to institute more stringent guidelines and add equipment to safeguard personnel. The operating characteristics of this refrigerant, and the additional equipment needed for the test A/C system, necessitate more complex automated test data acquisition and control. The addition of an internal heat exchanger in the CO2 A/C system is an example of the changes required. Different thermal characteristics introduced by this refrigerants mean that new measurement devices such as higher-pressure transducers are required. Compatibility between test stand sealing materials, hose assemblies, etc., and the refrigerant must be addressed.

Fulfillment of SULEV standards without catalyst - this is a target engineers at IAV have been working on since the middle of the 1990s. The core of this development is an advanced steam engine with a high performance burner. This burner features extremely low raw pollutant emission. This paper describes new solutions that were found to solve the challenging tasks in the development of such an engine concept.

The use of cutting fluid in machining operations not only poses a health risk to workers but also creates environmental challenges associated with fluid treatment and disposal. In an effort to minimize these concerns and eliminate the costs associated with cutting fluids, e.g., purchase, maintenance, and treatment, dry machining is increasingly being considered as an alternative. This paper is focused on comparing dry and wet machining approaches from several perspectives, including air quality, product quality, and economics. Both experimental and analytical work is presented. Experiments have been performed to determine the effect cutting fluid has on product quality and aerosol generation in the wet and dry turning of gray cast iron. To compare costs in wet and dry turning, a cost model, which includes cutting fluid-related components, has also been established.

The demands on valve seat inserts are that they should have enhanced wear resistance and machinability using non-environmentally hazardous materials at a reasonably low cost. Research into the possibility of producing a new valve seat insert material which fulfills such demands was therefore made. As a result Hitachi Powdered Metals (HPM) has developed a new material which uses dispersed die steel hard particles in the production of intake valve seat inserts.

Test standards for evaluating filters should provide uniform methods for the quantitative performance evaluation. Currently, automotive air induction filters are tested according to the SAE J726 standard. This standard recommends measurement of the gravimetric initial and final efficiencies. Measurement of gravimetric efficiencies provides limited information on filter behavior, since the information about the size of particles penetrating the filter is not included. In addition, the measurement of the initial gravimetric efficiency does not provide sufficient information on the initial stage of filtration. Determination of the efficiency at the initial stage of filtration is critical, since at this stage filters show their lowest efficiency, which can have an adverse effect on engine wear. To overcome this problem and to obtain more knowledge on the initial stage of filtration, the initial gravimetric efficiency was measured at different levels of dust loading.

The forming of alloys from the liquid state can be realized thanks to various casting technologies where the temperature of the metal is high enough to fill a given die correctly. A variety of casting defects often occur in the final part, such as gas porosity, shrinkage porosity and hot cracking. In the case of the magnesium foundry, all handling of molten metal requires serious safety precautions to avoid explosion and burning. Protective gas mixtures (SF6, SO2, CO2) are used to minimize the ignition risks but have a bad impact on the environment. The semi-solid forming operates using a lower temperature in the solidus-liquidus range and seems to be interesting, in particular, for the quality requests of the die caster and for safety and a clean environment. The purpose of this paper is to present the mechanical results of tensile tests carried out on magnesium standard samples, which are cast by Thixomag® process from the semi-solid state.

The evolution toward the use of electrostatic painting processes has been driven primarily by environmental legislation and efforts to improve efficiencies in the painting process. The development of conductive substrate material compliments the industry trend toward a green environment through further reductions in emissions of volatile organic compounds during the painting process. Traditionally, electrostatic painting of thermoplastics requires that a conductive primer be applied to the substrate prior to topcoat application. The conductive polymer blend of polyphenylene ether and polyamide provides sufficient conductivity to eliminate usage of conductive primers. Additional benefits include improved transfer efficiencies of the primer and top coat systems, uniform film builds across the part, and improved painting of complex geometries.

One of the main drawbacks of the NOx adsorber technology vs. the other leading approach for high level NOx conversion, namely selective catalytic reduction, is its high sensitivity to sulfur. In spite of the likely availability of ultra-low sulfur fuel and protecting devices like sulfur traps, and furthermore taking into consideration additional sulfur sources such as engine oil and lubricants, a desulfurization strategy will be essential to the commercial implementation of NOx adsorber catalysts on diesel vehicles. The results presented in this paper were obtained on NOx adsorbers with proven thermal durability and efficiency in diesel engine exhaust. They show NOx performance recovery following severe sulfur poisoning, after desulfation under temperature and air/fuel mixture conditions compatible with diesel engine operation. In addition, different desulfurization tactics, tested on a synthetic gas bench simulating diesel exhaust, are depicted and discussed.

Selective Catalytic Reduction (SCR) with NH3 or urea is one of the most effective methods for removal of NOx in exhaust from HD diesel engines with potential for achieving more than 90% NOx-reduction measured in the European transient or a US HD FTP test cycle. The present paper describes the following two systems; One OEM UREA-SCR SILENCER, comprising a silencer with built-in catalyst. The system was tested on a Scania DC1205 320 kW diesel engine, which was calibrated for the Euro II emission standard. The test results showed that it is possible to reduce more than 85% of the NOx emission with an insignificant NH3 slip in the ETC transient test cycle. The pressure-drop of the system was measured at 80% of that of the engine's original silencer and the silencing performance was improved for low frequencies below 125 Hz. One RETROFIT UREA-SCR SYSTEM for HD engines, comprising a silencer with built-in catalyst, an electronic urea injection control system, urea injection and a urea tank.

As part of a California Selective Catalyst Reduction (SCR) system demonstration and evaluation project [13], the authors and their industrial partners have conducted engine dynamometer emissions tests of SCR systems. The transient Federal Test Procedure (FTP) cycle and 13 Mode European Stationary Cycle (ESC) were conducted using certification diesel fuel with 300-500 ppm of sulfur. This paper reviews the performance of the first system to meet the goal of attaining 1 g/bhp-hr NOx emissions in the transient FTP cycle on a 1999 DDC Series 60 engine that has an initial 4 g/bhp-hr level. This paper discusses key characteristics of a typical automotive SCR system and then presents the results and analysis of the engine dynamometer emission testing of a SCR system. The paper concludes with a discussion of the challenges involved in on-road operation of the system.

A catalytic deSoot-deNOx system, comprising Pt and Ce fuel additives, a Pt impregnated wall-flow monolith soot filter and a vanadia-type monolithic NH3 - SCR catalyst, was tested with a 2 cylinder DI diesel engine. The soot removal efficiency of the filter was 98-99% (mass), the balance temperature (stationary pressure drop) was 315 °C at an engine load of 55%. The NOx-emission at high loads is around 15% lower than those of engine running without fuel additives. The NOx conversion ranged from 40 to 73%, at a NH3/NOx ratio of 0.9, both measured at a GHSV of 52,000 l/l/h. The maximum NOx conversion was obtained at 400 °C. No deactivation was observed after 380 h time on stream.

The LEV II and EURO V legislation in 2007/2008 require a high conversion level for nitrogen oxides to meet the emission levels for diesel SUVs and trucks. Therefore, U.S. and European truck manufacturers are considering the introduction of urea SCR systems no later than model year 2005. The current SCR catalysts are based mainly on systems derived from stationary power plant applications. Therefore, improved washcoat based monolith catalysts were developed using standard types of formulations. These catalysts achieved high conversion levels similar to extruded systems in passenger car and truck test cycles. However, to meet further tightening of standards, a new class of catalysts was developed. These advanced type of catalytic coatings proved to be equivalent or even better than standard washcoat formulations. Results will be shown from ESC, MVEG and US-FTP 75 tests to illustrate the progress in catalyst design for urea SCR.

Water-emulsified diesel fuel technology has been proven to reduce nitrogen oxides (NOx) and particulate matter (PM) simultaneously at relatively low cost compared to other pollution-reducing strategies. While the mechanisms which result in these reductions have been postulated, the development of new analytical tools to measure in-cylinder soot formation using optically accessible engines can lead to a deeper understanding of combustion and the chemical and physical mechanisms when water is present during combustion. In this study, an optically accessible single cylinder engine was used to study how water brought into the combustion chamber via an emulsified fuel changes the combustion process and thereby reduces emissions. In-cylinder measurements of relative soot concentrations were used to determine the effect of water-emulsified fuel on soot formation.

Particulate emission control from diesel engines is one of the major concerns in the urban areas in California. Recently, regulations have been proposed for stringent PM emission requirements from both existing and new diesel engines. As a result, particulate emission control from urban diesel engines using advanced particulate filter technology is being evaluated at several locations in California. Although ceramic based particle filters are well known for high PM reductions, the lack of effective and durable regeneration system has limited their applications. The continuously regenerated diesel particulate filter (CRDPF) technology discussed in this presentation, solves this problem by catalytically oxidizing NO present in the diesel exhaust to NO2 which is utilized to continuously combust the engine soot under the typical diesel engine operating condition.

Particulate emission from diesel engines is one of the most important pollutants in urban areas. As a result, particulate emission control from urban bus diesel engines using particle filter technology is being evaluated at several locations in the US. A project entitled “Clean Diesel Demonstration Program” has been initiated by NY City Transit under the supervision of NY State DEC and with active participation from several industrial partners. Under this program, several NY City transit buses with DDC Series 50 engines have been equipped with continuously regenerating diesel particulate filter system and are operating with ultra low sulfur diesel (< 30 ppm S) in transit service in Manhattan since February 2000. These buses are being evaluated over a 8-9 month period for operations, maintainability and durability of the particulate filter.

The aggressive reduction of future diesel engine NOx emission limits forces the heavy- and light-duty diesel engine manufacturers to develop means to comply with stringent legislation. As a result, different exhaust emission control technologies applicable to NOx have been the subject of many investigations. One of these systems is the NOx adsorber catalyst, which has shown high NOx conversion rates during previous investigations with acceptable fuel consumption penalties. In addition, the NOx adsorber catalyst does not require a secondary on-board reductant. However, the NOx adsorber catalyst also represents the most sulfur sensitive emissions control device currently under investigation for advanced NOx control. To remove the sulfur introduced into the system through the diesel fuel and stored on the catalyst sites during operation, specific regeneration strategies and boundary conditions were investigated and developed.

Urea-SCR system consisted of combined deNOx catalysts with wide range of temperature window, injector, sensor and injection controller. Synthetic gas activity test and NOx conversion efficiency test on the engine bench were carried out to evaluate and improve the performance of this system. To better suit the application of the urea-SCR system without engine modification, temperature of catalyst and engine RPM were used as input data to control amounts of urea aqueous solution that reacts with NOx. We concentrated on designing types of deNOx catalysts and controlling amounts of urea solution under different driving conditions to achieve higher NOx reduction and wider temperature window. Designed urea-SCR system showed substantial NOx reduction performance and relatively wide temperature window under different driving conditions.

One of the most attractive features of hybrid vehicles powered by SI-engines with three way catalysts is the potential of reaching extremely low emissions. In conventional drive trains, limitations in the air/fuel control result in lambda excursions during transients. These deviations from the ideal lambda result in increased emissions. In a hybrid vehicle, rapid load and speed changes of the SI-engine could be limited to an acceptable level as the battery acts as a power buffer. However, the efficiency of charging and discharging the battery is rather low, which means that excessive power buffering will increase the fuel consumption of the vehicle. Thus it is of great importance to know what degree of speed and load changes the air/fuel control system could cope with without an increase in emissions.