Search Results

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.

Cavity reinforcement materials are used in the automotive industry to stiffen hollow cavities in vehicle body constructions. Typical areas of use include the engine rails, rocker panels, roof support or any other cavity in need of structural reinforcement. Use of these materials can allow for significant reductions in vehicle weight and increase structural stiffness with minimal impact to production tooling. Additional benefits can be gained by using the material as a physical barrier to the propagation of noise, water and dust. The objective of this paper is to describe a case study which implemented a new type of cavity reinforcing material to improve low frequency vehicle noise and vibration characteristics.

Complete data sets (i.e., when all components within a given sample have explicit failure mileage) are a rarity in automotive field data analysis. More typically, only a few components of the sample would fail and the respective failure mileage would be recorded. In order to correctly estimate the reliability function, however, one would need to know the (censoring) mileage on the non-failed components. The paper discusses a procedure to estimate the censoring mileage and, ultimately, the reliability function for a component of interest. The paper further argues that a similar procedure can be applied to the total time on test estimation in the reliability growth analysis.

Due to increased legal and market demands, the weight of a conventional car body will most likely increase in the future. At the same time, environmental demands will become stronger and weight reduction will play an important part in fulfilling them. These demands are contradicting and there are mainly two things that can solve it: The use of new materials and further optimization of the structure. High strength steel is the easiest way to implement improved materials in an integrated body structure. Press hardened steel is one of the most promising manufacturing techniques and in this project a B-pillar reinforcement was developed as an example. For linear analyses, structural optimization methods have been used for quite a while, but for crash simulations, trial and error has been the only alternative. One part of the project was to evaluate how the response surface method could be applied to car crash simulations. The results of the project were very good.

Recently, it has been demonstrated experimentally that the so-called “whiplash” response during low velocity rear-end collisions may produce a spontaneously resolving strain injury to muscles of the neck, but that injury to other spinal elements is biomechanically improbable. This paper reviews the results of these studies as a means of addressing the longstanding controversy which surrounds “whiplash” and the claims that the “whiplash” response produces more extensive injuries. It is concluded that there are no objective, experimentally-based scientific data to support the concept that the low-velocity “whiplash” response is capable of producing any injuries beyond those to the cervical musculature.

Keeping in view the current on-going developments in the field of automobile restraint systems, the advent of additional regulatory requirements for occupant protection has driven the development of a new generation of inflatable seat belt restraint system (IRS). Such a device has been developed for vehicle and integrated structural seat mounted applications. During the development of the IRS it became evident that a minimum performance specification for the inflatable assembly portion of the system was in order, such that the overall effectiveness could be measured prior to its introduction into the market place.

Predictions of occupant motion in passenger vehicles undergoing rollovers have been hampered by the uncertainties of the vehicular motion. These uncertainties arise due to a host of factors which may be difficult to quantify, such as trip conditions, vehicle/terrain interaction dynamics and mass eccentricities. In this paper the initial segment of a roll sequence of high angular velocity (greater than 4 radians per second) about a longitudinal axis is examined. The resultant unrestrained motions of the near and far side occupants are studied. To facilitate this analysis a mathematical model has been developed which incorporates dynamic characteristics of the occupant, the vehicle and the terrain surface. The analysis is carried through the first significant vehicle/ground impact following roll initiation. Occupant kinematics are described.

The automotive seating industry will always be interested in understanding what the end-consumer expects and wants in terms of comfort. Even in the face of a movement towards comfort quantification through various measurement technologies, surveys are, and will always be, the best way to understand comfort. With this said, it is surprising that the published seat comfort research does not provide a standard survey demonstrated to be reliable and valid. Based on the fact that seat comfort development relies so heavily on subjective data, one would think that, in order to make design decisions with minimal risk, a reliable and valid survey is a prerequisite. This paper’s contribution is significant in that it provides a survey with acceptable test-retest reliability, internal consistency, criterion-related validity, and construct validity. It also details a more suitable approach to data analysis that should markedly improve the process of designing a comfortable seat.

This paper describes the development and use of new types of Physical Vapor Deposition (PVD) equipment and deposition technology for thin film hard coatings on a variety of large heavy duty stamping tools. The life of the tools increased significantly, beyond the limits of the presently available coating technologies (Chemical Vapor Deposition - CVD and Thermal Diffusion - TD). The pick-up is eliminated, the surface finish of the parts is improved and the process friction is reduced. Coated stock is handled better, as well as hot rolled high strength heavy gage steel up to 10 mm. thickness. This technique allowed parts up to 725 × 725 × 250 mm. and 450 kg. to be coated, while coating of parts twice the size and mass is possible in the near future.

Hot Metal Gas Forming is an innovative metal forming technique with the potential to leapfrog conventional metal forming techniques of structural steel components for automotive and aerospace industry. HMGF is an outgrowth of superplastic forming (SPF) and hot blow forming (HBF) techniques that the aerospace industry developed to form aluminum and titanium structures. The goal of this program is to develop the HMGF process and prove its production readiness for wide spread use in the Automotive and Aerospace industries by proving process robustness. An early process concept is shown below.

The future development of two-stroke engines will be conditioned by the drastic reduction of pollutant emission, especially of hydrocarbon. This goal is not achievable only by scavenging improvement, rather a new quality of mixture formation using direct injection is imposed. However, the internal mixture formation in a large range of speed and load, considering the scavenge flow particularities of two-stroke engines as well, appears as an extremely complex process. Thereby a numerical simulation is in this case very effective for the adaptation of a direct injection method at the engine. The paper presents a concept for modeling and optimization of the mixture formation process within a high-speed two-stroke engine with liquid fuel injection system. The injection system generates a pressure pulse which is not dependent on the engine speed.

High specific power output two-stroke engine for snowmobile use was converted to a Direct Fuel Injection (DFI) engine, in order to achieve lower HC emission by avoiding fuel short circuiting and to obtain higher specific power output by increasing induction air and optimizing A/F. High pressure single fluid fuel system was chosen because of extremely high fuel delivery rate. The fuel injector and its location were investigated and optimized for better mixture formation and lower HC emission. 140kW/L level specific power output, maximum engine speed of 9000 rpm, and 1/2 the level of HC emissions were obtained.

An attempt to reduce the HC emission of a two-stroke engine was carried out. A simple homogeneous charge combustion created with a Direct Fuel Injection (DFI) system was applied to a Personal Water Craft (PWC) engine. 1/4 HC emission of the base carbureted engine was obtained in International Council of Marine Industry Association (ICOMIA) driving mode due to the exclusion of fuel short-circuiting. Then stratified charge combustion was introduced. A numerical simulation of air and spray motion was performed and mixture formation was optimized. The low load misfiring was completely overcome and finally, less than 1/8 HC emission was achieved.

The IAPAC Direct fuel Injection (DI) system, developed by IFP, has already well proven its capability to reduce pollutants emissions and fuel consumption of 2-stroke engines. This crankcase Compressed Air Assisted Fuel Injection Process allowing the introduction of the fuel separately from the scavenging air, minimizes the fuel short-circuiting. In earlier works, results of the implementation of the IAPAC system on cylinder displacement from 125 cc to 400 cc have been presented in various papers. These first prototypes were all using a camshaft to drive the IAPAC DI poppet valve, which was considered as a limitation for applying this system to small displacement 2-stroke engines. The new SCIP™ system is no more using a camshaft neither driveshaft, or any electric power supply to drive the DI air assisted injection valve.

An experimental investigation was carried out to highlight the impact of different catalytic exhaust systems of a typical European two-stroke engine for small scooters on exhaust emissions and on engine performances. In particular different chemical compositions of the active coating materials and different precious metal loads were tested, and several geometries of the monolith in the exhaust system were analyzed. The influence of different carburetor settings on the efficiency of the catalyst and on engine performance was also evaluated. Finally, durability tests were performed, by monitoring the efficiency of the catalyst during a 12000 km aging test.

A project was conducted by Southwest Research Institute on behalf of the California Air Resources Board and the South Coast Air Quality Management District to demonstrate the technical feasibility of utilizing closed-loop three-way catalyst technology in off-road equipment applications. Five representative engines were selected, and baseline emission-tested using both gasoline and LPG. Emission reduction systems, employing three-way catalyst technology with electronic fuel control, were designed and installed on two of the engines. The engines were then installed in a fork lift and a pump system, and limited durability testing was performed. Results showed that low emission levels, easily meeting CARB's newly adopted large spark-ignited engine emission standards, could be achieved.