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Technical Paper

Mobility and fuel economy of hybrid-driven vehicles in terrain~Results from computer simulation

2000-06-12
2000-05-0394
An important requirement for the application of hybrid drives in future terrain vehicles is their competitiveness with regard to the driving properties and the fuel economy. Therefore, a two-axle, all-wheel-driven military transport vehicle equipped with a serial hybrid propulsion system has been regarded and examined by computer simulation. The tool, used for this purpose, is the simulation program ORSIS, (Off Road Systems Interactive Simulation), which has been developed at the University of the Federal Armed Forces in Hamburg. By generating a realistic surrounding area with reproducible conditions ORSIS allows an objective comparison of different vehicle types and the investigation of the influence of modified vehicle parameters. The paper presents results from computer simulations which include acceleration and braking procedures, determination of maximum drawbar pull, and the estimation of fuel consumption under realistic conditions by driving on determined routes.
Technical Paper

The development of warm-up control strategies for a methanol reformer fuel cell vehicle

2000-06-12
2000-05-0330
A fuel-cell-powered vehicle requires a plentiful supply of hydrogen to achieve good performance. This can be produced from methanol via an on-board reformer and gas clean-up unit. Since the reformer can take several minutes to reach its operating temperature, it is initially necessary to provide an alternative power source, such as a battery or ultra-capacitor, in order to drive the vehicle. This paper describes the use of a fuel cell vehicle simulation to predict behavior over a drive cycle from a cold start and to evaluate different warm-up control strategies in terms of performance and fuel efficiency.
Technical Paper

Experimental Study on Diesel Nitrogen Oxide Reduction By Exhaust Gas Recirculation

2000-06-12
2000-05-0335
This paper concerns mainly with the research work of diesel nitrogen oxide reduction by Exhaust Gas Recirculation (EGR). Using exhaust gas cleaned by a high efficiency bag filter as EGR gas, a 1110 DI diesel engine test bed was set up, and tests were made to investigate the EGR effects on engine performances, including engine emissions and fuel economy. The results showed that the EGR could be used as an effective way to reduce diesel nitrogen oxides with very little economy penalty. When the engine works at low or moderate loads, 25 to 40 percent of the EGR rate is good for better trade-off of engine economy and emissions. The nitrogen oxide reduction efficiency can be as high as 50% to 60% based on emission concentrations, and can be even higher based on total exhaust gas emissions of nitrogen oxides. Larger EGR rate can attain higher nitrogen oxide reduction efficiency, but the engine economy, HC and CO emissions will worsen.
Technical Paper

Analytical Design of Muffler Based on Transmission Loss Calculation

2000-06-12
2000-05-0311
As in many field today, a significant gap has developed between theory and practice in muffler design. The theory often does not appreciate the relevant practical concerns associated with the design process, while the designer often has difficulty in properly interpreting theoretical results for practical use. In this study, transmission Loss calculation on basic muffler elements is firstly considered. And then transmission loss on real muffler is compared with experimental results. We also found good agreement between prediction and experiment results. Finally we compared transmission loss with exhaust tailpipe noise on real car
Technical Paper

Three-way catalysts for partial lean-burn engine vehicle

2000-06-12
2000-05-0322
Emission of carbon dioxide from mobile sources seriously concerned to solve greenhouse effect and high price of gasoline in some countries have resulted in the development of lean-burn concept engine. In spite of many studies on the lean deNOx catalyst, we have no clear solution to obtain high fuel economy and high efficiency of NOx conversion in lean-burn application. This paper describes applicability and problems of NOx adsorber system to partial lean-burn vehicle, the development of three-way catalyst with improvement of washcoat technology based on three-way catalyst used for gasoline application, and comparison test results of evaluations is synthesized gas activity test, Federal Test Procedure (FTP) test, etc. This study shows improved three-way catalysts in partial lean- burn vehicle have max. 89% of NOx conversion in FTP without adding rich spike and regeneration functions to engine management system.
Technical Paper

Numerical Simulation and Optimum Design of Automotive Catalytic Converters

2000-06-12
2000-05-0309
A fluid dynamic mathematical model of the room airflow in monolith was established by an equivalent continuum approach. The commercial CFD code STAR-CD was used to simulate multi-dimensional steady flows in automotive catalytic converters. In order to verify the fluid dynamic model of the converter, a three-hole Pitot tube was adopted to measure the velocity distribution at the rear of the monolith. Computing results are in good agreement with experiments, which means the established model is feasible and can be applied to predict the flow performances of various catalytic converters. Then, the enhanced diffusion header (EDH) converters and oblique diffuser converters with different configurations were designed and simulated by the CFD code. Simulation results indicate that EDH and an oblique diffuser can improve the flow uniformity and decrease pressure loss in the converters. These results provide a useful guide for the optimum design of automotive catalytic converters.
Technical Paper

The effect of engine misfire on catalytic converter and vehicle emissions

2000-06-12
2000-05-0325
A conventional automotive emission control system depends on the measurements provided by various sensors to control the air-fuel (A/F) ratio. Maintaining the A/F ratio close to stoichiometry permits catalytic converter to operate in an optimized efficiency, which reduces the exhaust emission. Malfunction resulted from engine misfire makes catalyst''s converting efficiency drop. Such a condition results in increased emissions as well as in damage to catalytic converters. So current researches are proceeded in response to the California OBD II (On-Board Diagnostics) and EOBD that will be adopted in Europe requirements for engine misfire detection in passenger vehicles. In this study, two methods to diagnose the misfire an approached: catalytic converter''s temperature measurement over the threshold exposure temperature to examine the catalyst''s damage, and the vehicle emission test over FTP-75 cycle by varying misfire rates.
Technical Paper

Numerical analysis of light-off performance and thermo-fluid characteristics in a three-way monolithic catalytic converter

2000-06-12
2000-05-0310
Mathematical modeling of three-way catalytic converter (3WCC) operation is used increasingly in the optimization of automobile converter systems. But almost all of previous computational models were based on "adiabatic one- channel" approach with the reaction kinetics computations, which is useful and efficient in predicting real-world performance of the catalyst. However, as long as flow maldistribution is not accounted for in the models, simulation results will not be reliable. In this work, two-dimensional performance prediction of catalyst coupled with turbulent reacting flow simulation has been performed and the results were compared with experimental data and one-channel simulation in the literature. The computational results from this study show the better prediction accuracy in terms of CO, HC and NO conversion efficiencies compared to those of 1-D adiabatic model. Varying cell density and hot spot moving pattern within the monolith during warm-up period are also considered.
Technical Paper

Scavenger free three-way catalyst with low hydrogen sulfide emission

2000-06-12
2000-05-0308
This study suggests new types of catalysts that show low hydrogen sulfide emission without scavenger such as NiO. Hydrogen sulfide can be reduced by changing the physicochemical properties of washcoat components. Synthesized gas activity tests were performed to investigate the effect of modified washcoat on hydrogen sulfide formation and catalytic activity. BET surface area tests, X- ray diffraction tests, and gas chromatography tests were also carried out to examine the characteristics of catalysts. Preparation methods for catalysts were focused on minimizing the adsorption of sulfur species on catalysts. The first approach is heat treatment of cerium oxide to reduce adsorption sites for sulfur compounds. But this leads to deterioration of CO and NOx conversion efficiencies. The second one is adding new types of promoters that increase thermal durability and dynamic oxygen storing function of cerium oxide.
Technical Paper

Experimental Study on the Influence of Motorcycle's Noise Reduction Through Structure and Dimension Variation of the Muffler

2000-06-12
2000-05-0303
With the rapidly development of motor technology, the environment pollution caused by motor exhaust gas and noise gets more and more attention. The paper presents the experimental study on influent factors of Motorcycle muffler noise reduction, including changes of length and radials of the muffler pipe, the ratio m of expand cavity, the size or shape of tail pipe, the position of isolation plate inside a cavity, and verify of the total volume of the muffler. Rules of muffler structure design are studied.
Technical Paper

Development of Hyundai ULEV system

2000-06-12
2000-05-0297
HYUNDAI has developed ULEV(Ultra Low Emission Vehicle) system for 01MY export vehicle with 2.0 liter DOHC Engine. The system features the reduction of raw emission during cold idle phase (including start) and the improvement of L.O.T.(Light-off Time) of Closed-Coupled catalyst(CCC). Injectors with small S.M.D.(Sauter-Mean diameter) and lean warm-up control were adopted to reduce cold raw emission. L.O.T. of catalyst is shortened by adopting Sus-Pipe Exhaust manifold, retarding spark timing excessively and optimizing catalyst volume and precious metal loading.
Technical Paper

New ways of fluid flow control in automobiles: Experience with exhaust gas aftertreatmetn control

2000-06-12
2000-05-0299
Flow control by fluidic devices - without moving parts - offers advantages of reliability and low cost. As an example of their automobile application based on authors'' long-time experience the paper describes a fluidic valve for switching exhaust gas flow in a NOx absorber into a by-pass during regeneration phase. The unique feature here is the fluidic valve being of monostable and of axisymmetric design, integrated into the absorber body. After development in aerodynamic laboratory, the final design was tested on engine test stand and finally in a car. This proved that the performance under high temperature and pulsation existing in exhaust systems is reliable and promising. Fluidic valves require, however, close matching with aerodynamic load. To optimize the exhaust system layout for the whole load-speed range and reaching minimum counter- pressure, both the components of exhaust system and control strategy have to be properly adopted.
Technical Paper

Exhaust emissions from medium- and high-mileage in-service cars with three- way catalytic emissions control system driven under Nordic driving conditions

2000-06-12
2000-05-0295
Exhasut emissions were determined from a fleet of some 50 cars that have been in normal private ownership service in Finnish driving conditions. These represent typical Nordic climate with strongly varying ambient temperatures between summer and winter months. All cars were petrol-fuelled, and had an up-to-date emissions control system based on a three-way catalytic converter. Tested vehicles represented model years 1990 to 1996. They had odometer ratings at the time of testing ranging from a low of 10,000 km up to a high of 373,000 km. The emissions performance was assessed using U.S. FTP75 urban during schedule. Testing was carried out at normal ambient temperatures (+22...23° ...). The paper reports an assessment of typical emissions performance as a function of distance driven encountered from normal TWC cars that have been in day-to-day use under sometimes quite rigorous driving conditions.
Technical Paper

Reducing Exhaust HC Emission at SI Engine Using Continuous and Synchronized Secondary Air Injection

2000-06-12
2000-05-0296
The effect of secondary air injection (SAI) on exhaust hydrocarbon (HC) emission has been investigated in a spark-ignition (SI) single cylinder engine operating at steady-state cold condition. Both continuous SAI and synchronized SAI, which corresponds to intermittent secondary air injection to exhaust port, are tested. Oxidation characteristics of HC are monitored with a FID analyzer and exhaust gas temperatures with thermocouples. Effects of exhaust air-fuel ratio (A/F), location of SAI, and engine-A/F have been investigated. Results show that HC reduction rate increases as the location of SAI is closer to the exhaust valve for both synchronized and continuous SAIs. HC emission decreases with increasing exhaust-A/F when exhaust-A/F is rich, and is relatively insensitive when exhaust-A/F is lean. In synchronized SAI, SAI timing has significant effect on HC reduction and exhaust gas temperature. Optimum SAI timing observed is ATDC 100° and 230°.
Technical Paper

Research of Employing an Electrostatic Centrifugal Precipitator to Collect Diesel Particulate

2000-06-12
2000-05-0289
An electrostatic centrifugal precipitator (ESCP) has been developed to trap diesel particulate. In the ESCP, particulate is charged by a corona field, and moves to the surface of the collecting plate due to electrical force. Particulate deposited on the collecting plate is removed to a hopper by the shear force of exhaust gas. Test results show that the ESCP has high trap efficiency with very low pressure drop, and the efficiency varies with the inlet exhaust gas velocity and temperature. The highest temperature under which the ESCP can perform normally is limited by the high temperature electrical properties of the gas. Compared with a wall-flow type diesel particulate filter, the ESCP has many advantages such as very low pressure drop, low cost and no regeneration.
Technical Paper

Ways to meet future emission standards for heavy Sports Utility Vehicles - SUV

2000-06-12
2000-05-0288
Diesel engines belong to the most efficient power sources for any kind of on-road vehicle, but especially in Europe increasingly for passenger cars. However, more stringent exhaust emission regulations, which will come into force world-wide in industrialised countries during the first decade of the next century will require NOx and particulate emissions to be reduced by up to 60% and more from today's levels. To meet these future emission standards particularly for heavier passenger vehicles, such as SUVs, Pickup Trucks and Light Commercial Vehicles, as well as for heavy luxury class passenger cars, the application of new technologies including advanced exhaust gas aftertreatment systems will be indispensable, especially in view of maintaining the thermal efficiency of diesel engines relative to gasoline engines.
Technical Paper

Effective particulates reduction in diesel engines through the use of fuel catalyzed particulate filters

2000-06-12
2000-05-0286
There is increasing worldwide interest in diesel particulate filters (DPF) because of their proven effectiveness in reducing exhaust smoke and particulate emissions. Fine particulates have been liked to human health. DPF use requires a means to secure the burn-out of the accumulated soot, a process called regeneration. If this is not achieved, the engine cannot continue to operate. A number of techniques are available, but most are complex, expensive or have a high electrical demand. The use of fuel additives to catalyze soot burn-out potentially solves the problem of securing regeneration reliably and at low cost. Work on organo-metallic fuel additives has shown that certain metals combine to give exceptional regeneration performance. Best performance was achieved with a combination of iron and strontium-based compounds.
Technical Paper

Trend toward weight reduction of automobile body in Japan

2000-06-12
2000-05-0240
With society demanding automobiles that provide higher fuel efficiency, safety of occupants in collisions and that at the end of their service life can be recycled with low environmental impact, the steel industry is tackling the needs of the automobile industry by developing ever-higher performance steel materials and simulation technologies that can demonstrate the performance of steel materials at the development stage without the need for costly prototype testing. In this paper, weight reduction of automobile body in Japan will be discussed. The main items will be as follows: (1) Development of Automobile Steel Sheets, (2) Materials for Automobile Bodies, (3) Materials and Technologies (Tailored Blanks, Hydroforming and Locally Quenching) for Reducing the Weight of Panels and Reinforcing members, (4) Future Prospects.
Technical Paper

Environment-Friendly Automotive Technologies in Korea

2000-06-12
2000-05-0007
As environmental concerns are getting increasingly important, world's automobile manufacturers are confronting the mounting pressure to increase the fuel efficiency, highly related to global warming-causing CO2 emissions, and to reduce the exhaust emissions. In order to resolve these issues, automotive companies in Korea also have been striving to develop many advanced technologies such as lean burn engine, direct injection gasoline engine (GDI), direct injection diesel engine, continuously variable transmission (CVT), vehicle lightweighting, lower emissions vehicle, recycling, and various alternative fuel vehicles (AFVs). AFVs include flexible fuel vehicle (FFV) on methanol, natural gas vehicle (NGV), LPG vehicle, hydrogen vehicle, electric vehicle (EV), hybrid electric vehicle (HEV), and fuel cells vehicle.
Technical Paper

The Engine: a Perspective on Human Life and Environments

2000-06-12
2000-05-0010
In the 17th century, Christiaan Huygens invented the first engine to save the labor, which is humanism. Nowadays, both gasoline (SI) and diesel (CI) engines hold the definite position as the prime mover of the current surface transport vehicles due to their superior power, energy density, and fuel economy. Although these engines give exceeding convenience to human life, they also have become the vanguard of environmental disruption. From this viewpoint, the author has tried to give a historical review and perspective on engine developments. Although it is said that further emission controls in CI engines are quite difficult, recent research work and prediction for both lower emissions and better fuel economy are discussed. It is concluded that CI engines will co-exist with SI engines in the future, part of which will be used in hybrid systems. Fuel cells will be widely utilized, and hydrogen internal combustion engines would be expected as well.
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