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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

Visualization techniques to identify and quantify sources and paths of exterior noise radiated from stationary and nonstationary vehicles

2000-06-12
2000-05-0326
In recent years, Nearfield Acoustical Holography (NAH) has been used to identify stationary vehicle exterior noise sources. However that application has usually been limited to individual components. Since powertrain noise sources are hidden within the engine compartment, it is difficult to use NAH to identify those sources and the associated partial field that combine to create the complete exterior noise field of a motor vehicle. Integrated Nearfield Acoustical Holography (INAH) has been developed to address these concerns: it is described here. The procedure entails sensing the sources inside the engine compartment by using an array of reference microphones, and then calculating the associated partial radiation fields by using NAH. In the second part of this paper, the use of farfield arrays is considered. Several array techniques have previously been applied to identify noise sources on moving vehicles.
Technical Paper

Automotive Seat Guide Line Study By Comparing Anthropometric Data between Eastern & Western People

2000-06-12
2000-05-0305
It is well known that there are some differences between eastern & western people's body size. But eastern people's physical condition is not considered enough in designing seat. In this study, it is tried to find the relationship of seat comfort differences between eastern and western people by analyzing anthropometic data and subjective seat comfort feeling. And some key point and direction of design concept is set up by considering their anthropomeric differences and subjective preference, and showed optimal guide lines of good seat for eastern & western people.
Technical Paper

Powertrain-related vehicle sound development

2000-06-12
2000-05-0301
This paper reflects an efficient and comprehensive approach for vehicle sound optimization integrated into the entire development process. It shows the benefits of early consideration of typical vehicle NVH features and of intensive interaction of P/T and vehicle responsibilities. The process presented here considers the typical restriction that acoustically representative prototypes of engines and vehicles are not available simultaneously at the early development phase. For process optimization at this stage, a method for vehicle interior noise estimation is developed, which bases on measurements from the P/T test bench only, while the vehicle transfer behavior for airborne and structure-borne noise is assumed to be similar to a favorable existing vehicle. This method enables to start with the pre- optimization of the pure P/T and its components by focusing on such approaches which are mainly relevant for the vehicle interior noise.
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

ACTIVE NOISE CONTROL WITH ARTIFICIAL NEURAL EXPERTS

2000-06-12
2000-05-0294
The aim of the project is related to active control of in-car noise. Basically, an artificially generated sound is superimposed on the unwanted interior noise in order to cancel it out. The canceling signal is obtained by suitable detection and processing of the interior noise so that the unwanted sound perceived by the human observer is considerably reduced. The core of the system consists of an ensemble of “experts' that are specialized in modeling the in-car noise for predefined engine rotation intervals. These are implemented by artificial neural networks, due to their well-known approximation capabilities. Tracking capabilities of the changes occurring in the environment are provided by adaptive weighting of the experts outputs. This action is driven by a discriminator that is able to distinguish between useful sounds (voice, radio, alarm signals) and unwanted noise.
Technical Paper

Noise analysis and modeling with neural networks and genetic algorithms

2000-06-12
2000-05-0291
The aim of the project is to reliably identify the set of constructive features responsible for the highest noise levels in the interior of motor vehicles. A simulation environment based on artificial intelligence techniques such as neural networks and genetic algorithms has been implemented. We used a system identification approach in order to approximate the functional relationship between the target noise series and the sets of constructive parameters corresponding to the cars. The noise levels were measured with a microphone positioned on the driver''s chair, and corresponded to a variation of the engine rotation of 600-900 rot/min. The database includes 45 different cars, each described by vectors of 67 constructive features.
Technical Paper

Linking evaluation of subjective tire tests on the road with objectively measured data

2000-06-12
2000-05-0279
Measurements of the initial values lead to an inverse and mathematically unprecisely formulated problem. A precise definition of an inverse problem is possible. It is to state a mathematical model of a physical process with clearly defined initial and exit values for the system behind the process. One can grasp the idea of an inverse problem by considering the tire as a copy of the objects of nature in a room with observations. Interpretation of nature is generally a result of an inverse problem. On one hand, the tire may be represented through the sensory organs and the nervous system as well as the experiences of the developer''s existing apparatus of the projection of reality. On the other hand, it may be represented by a physical law or a model that can be confirmed or is to be refuted with teh help of suitable measurements.
Technical Paper

The Driver Side Air Bag Development for Light Truck

2000-06-12
2000-05-0273
This study presents a driver side airbag development procedure of a cab-over type light truck which weighs from 2000kg to 3500kg. For the airbag development, crash tests are performed according to FMVSS 208 regulation used for passenger car. Test results are used to develop an airbag ECU and get a vehicle pulse for computer simulation and sled test. This study proposes a modified airbag deployment criterion, T150mm−25ms, for cab-over type truck. A finite element computer model for occupant behavior analysis is developed and utilized to find optimal airbag parameter values. Then, sled test is performed to verify the computed airbag parameter values and tune them if necessary. Finally, crash test equipped with airbag is performed again to check the improvement of injury coefficients. This study suggests three things to overcome the difficulties in femur protection capability.
Technical Paper

Development of the All-Aluminum Light Body Structure for the Hybrid Electric Vehicle

2000-06-12
2000-05-0267
Global environmental problems have become the focus of much attention in recent years as an issue to be dealt with on an international scale. To alleviate these problems, automobile manufacturers are attempting to develop recyclable body parts and reduce vehicle exhaust emissions. These efforts have spurred the development of Low Emission Vehicles (LEV) and recyclable materials. One type of LEV is called the Hybrid Electric Vehicle which functions as either an electric car or an internal combustion vehicle and can operate as either type according to driving conditions. This hybrid vehicle is superior to conventional automobiles due to reduced exhaust emissions yet has the disadvantage of increased weight since it holds motors, batteries, and drivetrain control systems as well as a conventional internal combustion engine. We succeeded in eliminating this disadvantage by developing a lighter body using aluminum structural material.
Technical Paper

The new generation of BMW child seat and occupant detection system SBE2

2000-06-12
2000-05-0274
A new generation of BMW child seat and occupant detection system SBE2 for a smart airbag system is described. The SBE2 system consists of two subsystems: OC (occupant classification) and FDS (field detection system). The OC system is a force-sensitive sensor array that measures a pressure profile. The FDS system detects child seat and occupant according to the change of electrical field generated by four capacitive plates. Combining the signals from both subsystems, the BMW SBE2 system can distinguish fully automatically between a child seat and a person.
Technical Paper

Intelligent headrest design for rear impact safety and driver's convenience

2000-06-12
2000-05-0263
This paper introduces intelligent headrest using DC motor, photo sensor, and piezo sensor. Intelligent headrest which follows driver''s head during driving can protect driver''s neck efficiently when the vehicle is crashed from rear direction. This paper, we propose an intelligent method of headrest movement. For this method, at first, we had to obtain the optimum information that is the gap between driver''s head and headrest from 10 tested people who included beginner and expert drivers. At second, we developed new control method using this data. As it were, if driver''s head moves forward, headrest has to follow to driver''s head, or else if driver push headrest, headrest has to move backward. For this method, we used photo and piezo sensors. The photo sensor was installed to check the distance between head and headrest, and the piezo sensor was installed to check pressure from driver''s head to headrest.
Technical Paper

A development of electronic load sensing proportioning valve for control of brake pressure using direct adaptive fuzzy algoirthm

2000-06-12
2000-05-0266
In the brake system a proportioning valve which reduces the brake pressure at each wheel cylinder for anti-locking of rear wheels is closely related with the safety of vehicles. But, it is impossible for a present proportioning valve to exactly control brake pressure because mechanically it is an open-loop control system. So, in this paper, we describe an electronic brake pressure distribution system using a direct adaptive fuzzy controller in order to exactly control brake pressure using a closed-loop control system. The object of electronic brake pressure distribution system is to change a cut-in pressure and a valve slop of proportioning valve in order to have better performance of brake system more than that of the previous systems.
Technical Paper

The Development of Lightweight Vehicle using Aluminum Space Frame Body

2000-06-12
2000-05-0261
Due to the environmental problem like as CO2 emission, energy problem and etc., many car makers are trying to reduce the weight of the vehicle. The most effective way to reduce the weight of vehicle is to use lighter materials, aluminum, magnesium, plastics. And weight reduction of body is more effective than the others. There are two kinds of lightweight body, aluminum monocoque body and aluminum space frame body. Aluminum space frame body has many advantages from the space frame structure and the use of lighter materials. So, many car makers are developing aluminum space frame body and in mass production of some kinds of car, eg. Sports car, electric vehicle and etc. For these reason, we have developed and aluminum space frame body vehicle with ATOZ model base. Using FEM analysis, we designed sections of extrusions(6061) and fabricated spaceframe skeleton by ARC welding.
Technical Paper

Study on PDE approach and its application to surface modeling of autobody

2000-06-12
2000-05-0258
At present most of software in styling and design, no matter single or integrate, utilize the spline curve as their basis method of surface creating. And the NURBS technology is applied broadly. However, considering the computing time, system resource, and in order to create high quality surface model quickly, the paper brings out and describes the PDE method and its application to surface modeling. PDE, that is partial differential equation, is a numerical method to solve boundary question. The paper will discuss the approach and its application in the following aspects: (1) Application type of the PDE in engineering; (2) Method to control surface shape; (3) Definition the boundary conditions; (4) Managing the CO four side face; (5) Managing the C1 four side face (6) Tackling the triangle face; (7) Interface of PDE to NURBS. The PDE method has many computing techniques, it is easy to write program, and the surface created using this method is smoother than the conventional method.
Technical Paper

Radial vibrations of tire tread-band at different rolling speeds

2000-06-12
2000-05-0254
The interaction tire-road at high speeds of rolling is a principal source of noise and vibration and influences the passenger comfort and safety. The paper presents the experimental and theoretical research on radial vibrations of tire tread-band at different rolling speeds. The experimental research involves the measurement of tread-band vibrations at 100 km/h, 140 km/h and 180 km/h rolling speeds. Also, the radial natural frequencies and corresponding mode shapes were measured. A two-dimensional finite element model was created for modal analysis and for study of tread-band radial vibrations at the mentioned rolling speeds. Likewise, the model enables the study of tire standing wave phenomenon. In order to correlate the model natural frequencies with the real tire ones, a model updating procedure was applied. The results offer useful information on the magnitude, on the circumferential distribution, and on the periodicity of tread-band radial vibrations.
Technical Paper

Identification of A Vehicle Pull Mechanism

2000-06-12
2000-05-0253
A vehicle pull problem is directly related to safety and comfort. Major parameters causing the pull problem are the PRAT and conicity of tires, the VRAT, cross camber, cross caster and other manufacturing uniformity of a vehicle, and road crown. The effects of these parameters are described in this paper. The significance of VRAT and PRAT is explained as pull matching parameters. Especially, conicity sensitivity and VRAT sensitivity with respect to the changes of cross camber and cross caster are given. To minimize the pull problem, it is shown that a co-work between vehicle and tire companies is necessary from the beginning of a vehicle development to the end
Technical Paper

Development of a new all-wheel-drive control system

2000-06-12
2000-05-0248
The new all-wheel-drive control system has been developed to improve stability, handling performance and safety under various road/operating conditions. This system consists of center differential and hydraulic transfer clutch which is electronically controlled according to road/operating condition. The center differential of this control system is in the form of composite planetary gear system without a starter ring. The output torque of transmission is distributed by this center differential 35% to front wheels and 65% to the rear wheels. It improves handling performance on dry road when the transfer clutch is open. On the other hand, when the slippery road condition is detected or motion of vehicle is disturbed, the actual torque distribution is modified by electronically controlled transfer clutch to improve stability and safety.
Technical Paper

Vehicle Driving Load Estimation for Longitudinal Motion Control

2000-06-12
2000-05-0249
An estimation algorithm for vehicle driving load has been proposed in this paper. Driving load is an important factor in a vehicle's longitudinal motion control. An approach using an observer is introduced to estimate driving load based on inexpensive RPM sensors currently being used in production vehicles. Also, the new torque estimation technique using neural network has been incorporated in this estimation algorithm to achieve better performance over variations in the automotive power transmissions process. The effectiveness of the observer-based method is demonstrated through the use of a nonlinear full vehicle simulation model in various scenarios. The proposed method using an observer has good performance, both over modeling error in powertrain system and under the uncertain environment of a running vehicle.
Technical Paper

A Study of Assist Control in Electric Power Steering - Driving Pattern Rule-Based Control -

2000-06-12
2000-05-0241
This paper describes a rule-based electric power steering control system wherein driving patterns are judged based on input torque change ratio in addition to steering angle and input torque and assist characteristics changed accordingly to achieve the most appropriate steering feeling. We installed a conventionally controlled system and one with the proposed control in a test vehicle and compared driving effort by studying electromyogram measurements. It has been shown by the results that driver effort has been reduced and steering wheel turnability has been improved without sacrificing conventional steering feeling. The proposed control is a first step toward improving steering feeling and achieving ideal assist control in electric power steering.
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