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With the increasing emphasis on fuel efficiency and environmentally friendly vehicles, much effort is being directed by the auto industry to develop efficient, lightweight and alternative-powered vehicles. One of the ongoing research programs at DaimlerChrysler's Liberty and Technical Affairs is not only aimed at reducing the overall weight of the automobile body structure, but also reducing the cost of manufacturing it. In addition, an automobile body structure needs to meet the requirements of noise, vibration and harshness (NVH), durability, crashworthiness and recyclability. The objective of this paper is to provide a review of the ongoing research and development activities leading to an automobile body structure that meets the above objectives. The paper highlights the many different technology development challenges faced during the process.

Increased international competition of automotive companies have lead to new approaches and concepts for the manufacturing processes, especially for body-in-white (BIW) manufacturing systems. The main issues are competitive cost advantages, shorter launch periods and quality of produced vehicles. The supplier acting as general contractor and the customer have applied a new approach for operating and engineering as well as installing a segmented BIW-system. This paper will present the conceptional approach based on an advanced operating concept to engineer and realize a competitive BIW-system.

A new approach to in-process monitoring has been described in earlier papers, based on non-contact sensors mounted right in the assembly weld tools. The current paper describes new approaches to sensor implementation, which have been developed and field tested in the past year. Several cases of broad distribution of sensors throughout assembly lines are described. These implementations include use of sensors both in-tool and at end of line stations. The networking of multiple stations to present data at multiple locations, as well as use of plant networks to allow users to view and analyse information at their desks is described. Recently, similar sensors have been applied with robots to provide multi-function inspection capability in a programmable station, ideal for use in a stamping facility. Such systems reduce the need for visual inspection as well as eliminating the need for individual part check fixtures.

More complicated parts, higher requirements concerning shape and dimension accuracy, reduction of forming steps and utilization of new innovative materials represent important development trends in the today’s automotive industry. Since these tendencies leads to more difficulties in forming, especially in deep drawing, it is essential for the industrial enterprises to increase the manufacturing stability. Therefore, it is necessary to identify methods which can lead to an improvement of the material flow during the forming operation. In this case, multpoint drawing technique, superposition of vibrations during forming and closed-loop control systems represent promising approaches to achieve improvements.

Autokinetics is a Rochester Hills MI design firm working with Armco, a supplier of stainless steel. Together, they have developed an architecture that replaces the traditional stamped and spot welded steel unibody with a novel stainless steel spaceframe architecture. Fabrication Rollformings Thin wall castings Progressive die stampings Plastic support and exterior panels Assembly - Spot, laser, and MIG welding Relative to conventional steel unibodies, the Autokinetics spaceframe architecture offers a number of projected advantages. Substantial mass reduction Increased safety Improved ride and NVH More flexible packaging Lower lifecycle impact Potential for paint shop elimination The obvious question that arises, and the one that this paper will answer, is: How does the Autokinetics spaceframe architecture compete on cost?

A marine gear is a reversible reduction gear provided in an inboard engine typically used as a propulsion unit for fishing boats. One of its functions is to provide “trolling speed” to make the boat go very slow. Some devices to attain the trolling speed is already available, in which hydraulic oil pressure for clutch coupling is mechanically controlled to achieve the boat's slow speed. However, conventional device is not satisfactory in view of performance and operational handiness. The new control system reported here resolves such problem by utilizing a solenoid to achieve optimal control over the hydraulic oil pressure. It assures easy handling, and provides the most desirable performance for a fishing boat to go dead slow. The system has an additional function to deal with another concern about a marine gear, that is, the rattling noise of the driving gear which often occurs while the engine is running in the low speed range.

In recent research, decreasing oil consumption and using a synthetic oil have been shown to be effective methods of reducing smoke emissions. However, the investigation of the constituents of white smoke and its environmental effect on humans have not been undertaken. The purpose of this investigation is to clarify the characteristics and compositions of white smoke and to analyze its environmental effect on humans using Ames test, and to evaluate a control for reduction of emitted matter by steady-state engine tests. Emitted matters(EM) from synthetic oil is less than that of semi-synthetic and mineral oils under the same test conditions. Emission after treatment resulted in the lowest EM when simulating the results of the ISO 6460 test, which results showed a decrease to about 1/10. EM from two-stroke engine mainly consists of unburned engine-oil and more than 95 % of EM is soluble organic fraction (SOF).

Reacent strict emisssion regulation requires inprovement in the contradictory turget, that is to say, more engine power per displacement and less pollutants. This target could be realized ZEXEL by increasing the allowable injection quantity in the nozzle with a smaller sac volume, and increasing the flow rate of nozzle hole without enlarging the nozzle orifice size. Sac volume of the super-mini sac nozzle is dereased to 0.17mm3, from 0.23-0.31 mm3 which is the minimum level of the conventional mini sac nozzle. Increase in injection flow rate was obtained by means of the “Extrude Horn” treatment which makes round and smooth both inner surface of the sac and the entrance edge of the orifice. The trade-off between NOx, HC emissions and the combustion noise was improved by optimizing the injection rate in low speed and low load range.

The simulation techniques play important role on contemporary engine design. In this study, computer fluid dynamics approach (CFD) was focused to design the intake and combustion system of the direct injection diesel engine for versatile use. A practicality was stressed as much as an accuracy to correspond to designer and researcher's requirements, such as close relationship to the engine performance and short period of computation. The correlation of the trapping efficiency and the swirl ratio was mainly focused. A steady flow rig tests and engine operation data were combined to improve their quality mutually.

It has been already scheduled to apply exhaust emission regulations onto motorcycles, intending to make exhaust gas cleaner. Several South-East Asian nations issued new regulations in 1996, then Japan in 1998, and European nations are planning to start stricter regulations from early 2000.The required emissions level of these new regulations are so strict that it is estimated that no engine will be able to pass the regulation without installing complicated devices, and a catalytic converter as well. The development of new technology in this category has become an urgent subject. This paper describes our development of an exhaust system including a honeycomb-type catalytic converter for large displacement 4 stroke motorcycle engines to meet even the proposed future regulations in Europe (EC Stage II) without sacrificing its performance. This paper also reports on observed troubles and our solutions during the development.

The purpose of this study was to find compatible specifications both of emission reduction and high power output with good throttle response for a sports utility motorcycle. In the emission reduction challenge, we examined equipping the exhaust system with a catalytic converter to achieve sufficient emission reduction. The catalytic converter, however, caused a temperature rise in the exhaust system, which caused a pressure propagation change. Additional muffler design optimization effectively maintained high performance and acceleration. The exhaust valve device was also optimized for emission reduction and high power output over a wide engine speed range. The optimized control of the exhaust valve was beneficial to preventing short-circuit of fresh mixture gas and early activation of the catalyst. Such comprehensive specifications could satisfy the performance and driveability characteristics required for sports utility motorcycles.

This paper describes the predicted results of acoustic transmission loss (T.L.) for a motorcycle muffler. First, the T.L. of a prototype muffler with one expansion chamber was obtained by measuring sound levels at the inlet and outlet ports of the muffler by speaker test. T.L. was then calculated by using a three-dimensional Finite-Element Method (FEM) for acoustic fields in the muffler. There was good coincidence between the calculated T.L. and experimentally observed data. Second, T.L. of the prototype muffler while attached to a motorcycle engine was measured. On this step, however, a similarly calculated T.L. using FEM to consider the effect of exhaust gas temperature in the muffler showed differences from the measured one. It was estimated that muffler body vibration sounds may affect the result. A dynamic analysis of the structure was carried out using FEM to obtain the eigen modes of the muffler body.

With an increasing number of vehicles, the reduction of traffic noise emissions becomes a greater social requirement. On the other hand, as users' tastes for motorcycles have diversified, it becomes important to develop and supply products to meet customers' requests within a short period. Therefore, it is a key factor to efficiently develop motorcycles which conform to the noise regulations. This paper describes concrete examples of currently utilized noise-source proving methods and noise reduction methods for motorcycles.

Recent advances in press and die building have provided the capability of restraining force (RF) variation during a sheet stamping stroke. Even though the commercial presses with VRF capabilities are now available, the full benefits cannot be attained because, for complex industrial stampings, it is difficult to select the VRF trajectory which will improve the stamping quality or achieve even more complex task of arriving at the desired design target. In this paper we demonstrate how numerical modeling can be used to select a proper VRF trajectory to achieve a postulated design target. The working numerical model using explicit LS-Dyna 3D code was successfully developed for time effective simulation of complex parts with variable binder force. Three case studies with the specific design targets of 1) springback, 2) punch force, and 3) maximum strain are presented and discussed. The results show strong nonlinear influence.

In deep drawing and drawing of car body parts the friction conditions are of great influence on process limits, on the robustness of the production process and on the quality of the produced parts. Beside the used lubricant, the friction conditions are influenced by the topography of the sheet metal surface and by the topography of the tool surface. This paper deals with the influence of sheet metal surfaces, coatings on sheet metal surfaces, tool surfaces, coatings on tool surfaces, and with the influence of the lubrication on the frictional behavior.

This paper shows the benefits of a new draw die design. To achieve an optimized contact pressure between blankholder and blank a segment-elastic blankholder in combination with a prismatic designed draw ring can be used. In this case the blankholder pressure is very equal distributed and can be influenced locally by varying the cushion pin forces. For this a multipoint cushion system is required. Within a new press concept as shown in this paper, this multipoint cushion system can be realized by short stroke hydraulic cylinders.

In 1997, Multimatic became involved in a project that is part of the Partnership for a New Generation of Vehicles (PNGV) program. The intent of the program is to develop technology that will allow very efficient passenger vehicles to be mass-produced. Ideally, the vehicles will offer performance and features comparable to those of current production mid-size sedans while achieving 80 mpg fuel economy. The goal of Phase 1 of the Hybrid Material Body Structure Development Project was to develop the lightest possible automotive body structure for a vehicle based on a current production mid-size sedan. The resulting design was to meet or exceed the stiffness performance of the existing steel structure while achieving the highest possible weight save.

Of the 1 million Tonnes of material used for body panels on cars and trucks in 1998, approximately, 57,000 Tonnes were plastic composites. Three material types, generically labeled SMC, RIM and Thermoplastic split this volume. In each case, specific performance criteria and costs dictated the use of plastic composites. Recently, SPECTRIM* HH 390, a polyurea RIM material, has replaced SMC as the material of choice on General Motors' Silverado and Sierra Sportside vehicles. Certain performance criteria as well as overall costs paved the way for this material to be approved and utilized on such a highly visible and important platform in the light truck market. Therefore, the entry of an ELPO capable RIM material widens the choice of plastic composites for body panel materials.

This paper will provide an overview of the need, requirements, and constraints governing the development and application of polymer composites in automotive body components. It will discuss the efforts underway to lead and support the technology developments required for the cost-effective application of these new materials in mass-produced vehicles. The requirements and constraints of customer-driven, mass-produced, energy-efficient vehicles with uncompromised cost, capacity and performance, drive careful consideration of an injection-molded thermoplastic approach to a composite automotive body. Recent progress with this approach will be reported and some next steps examined.