Search Results

(Paint) film as an alternative to spray applied paint has received growing attention in recent years. The potential for economic and environmental advantage and quality enhancement with this technology has been reported in several technical papers (Ref. 1, 3 and 4). The actual practice of film finishing, however, has received only limited notice. Film finishes have been applied to aluminum, stainless steel, PVC, and ABS. Starting in 1982, part applications include: wheel covers, door edge guards, window surrounds, roof drip moldings, lower windshield moldings, rocker panels, body side moldings, B pillars, and A pillars. Industry awareness and acceptance of film finishing as a viable alternative to spray applied paint is increasing. The two technologies are similar in many ways, yet distinctly different in other ways. They share a common goal: To yield a durable finish, economically and with superior visual impact. This paper reviews the unique aspects of film finishing.

To reduce the Body in White (BIW) mass, it is necessary to expand the application of Advanced High-Strength Steels (AHSS) to complex shaped parts. In order to apply AHSS to complex shaped parts with thinner gauge, high formability steel is required. However, higher strength steels tend to display lower elongations, compared with low/medium strength steels. Current AHSS are applied to limited parts for this reason. The new 1.2GPa material, with high formability, was developed to solve this issue. The mechanical property targets for the high elongation 1.2GPa material were achieved by precise metallurgical optimization. Many material aspects were studied, such as formability, weldabilty, impact strength, and delayed fracture. As the result of this development, 1.2GPa AHSS has been applied to a new vehicle launched in 2013.The application of this material was the 1st in the world, and achieved a 11kg mass reduction.

The demand for improved fuel economy in both cars and trucks has emphasized the need for lighter weight components. The application of high strength steel to wheels, both rim and disc, represents a significant opportunity for the automotive industry. This paper discusses the Ranger HSLA wheel program that achieved a 9.7 lbs. per vehicle weight savings relative to a plain carbon steel wheel of the same design. It describes the Ranger wheel specifications, the material selection, the metallurgical considerations of applying HSLA to wheels, and HSLA arc and flash butt welding. The Ranger wheel design and the development of the manufacturing process is discussed, including design modifications to accommodate the lighter gage. The results demonstrate that wheels can be successfully manufactured from low sulfur 60XK HSLA steel in a conventional high volume process (stamped disc and rolled rim) to meet all wheel performance requirements and achieve a significant weight reduction.

This paper describes the Electronic Air Suspension (EAS) System developed by Ford Motor Company. Design trade-offs between load-carrying capacity necessary with conventional steel spring suspension systems and riding comfort are avoided when today's microcomputer technology is combined with a leveling air spring suspension. An electric air compressor with regenerative air dryer, three electronic “Hall Effect” height sensors, four air springs with integral solenoids, and a control module with a single chip microcomputer are the key EAS System components discussed.

Simulation has become an integral part in the design and development of an automotive air-conditioning (AC) system. Simulation is widely used for both system level and component level analyses and are carried out with one-dimensional (1D) and Computational Fluid Dynamics (CFD) tools. This paper describes a 1D approach to model refrigerant loop and vehicle cabin to simulate the soak and cool down analysis. Soak and cool down is one of the important tests that is carried out to test the performance of a heating, ventilation and air-conditioning (HVAC) system of a vehicle. Ability to simulate this cool down cycle is thus very useful. 1D modeling is done for the two-phase flow through the refrigerant loop and air flow across the heat exchangers and cabin with the commercial software AMESim. The model is able to predict refrigerant pressure and temperature inside the loop at different points in the cycle.

A theoretical model is presented for predicting springback of wide sheet metal subjected to 2D-stretch-bending operation. The material is assumed to be normal anisotropic with n-th power hardening law, σ = Fεn. Two types of stretch-bending experiment, bending with simultaneous stretching and stretch-bending followed by consecutive re-stretching, is conducted using AK sheet steel and sheet aluminum alloy A5182-O. The measured values of springback are in good agreement with analytical ones for a wide range of bending radii, stretching forces, and loading conditions. Furthermore, a calculation method for predicting springback configurations of 2D sheet metal parts with arbitrary cross-sections which include both stretch-bending and stretch-bending-unbending deformation is proposed.

This paper describes the engineering, manufacturing and integration necessary to produce the Corvette's first ever all-aluminum spaceframe (see Figure 1). The engineering and manufacturing of the spaceframe was a joint venture between General Motors and suppliers ALCOA (Aluminum Company of America) and Dana Corporation. ALCOA led the initial design of the spaceframe; Dana Corp led the manufacturing; General Motors' Engineering and Manufacturing groups led the integration of the assembly. The aluminum spaceframe design is modeled after the baseline steel structure of the Corvette coupe. The aluminum spaceframe reduces 140 lbs from the steel baseline and enters the plant at 285 lbs. This frame allows the 2006 Corvette Z06 to enter the market at a 3100 lbs curb weight. Aluminum casting, extruding, stamping, hydroforming, laser welding, Metal Inert Gas (MIG) welding, Self Pierce Riveting (SPR), and full spaceframe machining make up the main technologies used to produce this spaceframe.

In order to reproduce heavy bass with a small diameter loudspeaker for automotive use similar to the intensity and low distortion of a home-use Hi-Fi system, a large volume velocity must be obtained. This is done by lowering the minimum resonant frequency of system and by linearly expanding the amplitude range of diaphragm. We have developed a 3-D woofer system using a centering suspension that consists of four tubes of square cross-section continuously laid in the circumferential direction and a cone suspension that has V-shaped pleats in both of the circumferential and diameter directions for the vibration system. The results are good acoustic characteristics in an automotive cabin that are low in distortion with high output in the low frequency range up to 100Hz.

Beside the automotive industry, where 2-cylinder inline engines are catching attention again, twin-cylinder configurations are quite usual in the small engine world. From stationary engines and range-extender use to small motorcycles up to big cruisers and K-Cars this engine architecture is used in many types of applications. Because of very good overall packaging, performance characteristics and not least the possibility of parts-commonality with 4-cylinder engines nearly every motorcycle manufacturer provides an inline twin in its model range. Especially for motorcycle applications where generally the engine is a rigid member of the frame and vibrations can be transferred directly to the rider an appropriate balancing system is required.

Traditional acoustic measurements inside any cavity have historically been conducted with a small number of microphones. By this means it is possible to gain information about parameters like frequencies, orders and sound pressures. However, a space-selective analysis is nearly impossible and it is not feasible to find the position of the sound sources in space in a practical way. While traditional beam forming systems with planar microphone arrays have enlarged the possibilities of acoustic measurements, they do not give comprehensive information about the sound sources in the entire vehicle interior. Therefore, the components of the Acoustic Camera of the GFal were extended by a spherical, acoustically transparent and omni-directional array. A new option is to map onto a common 3D-CAD-model of the object of interest, for instance a vehicle interior. The advantages and disadvantages of 2D- and 3D-mappings will be discussed in the paper.

A continuously growing demand comes from the automotive industry in order to get an experimental tool allowing for the optimization of materials and sound insulating products implementation inside the car, so as to propose the best acoustic performance at reduced costs. The acoustical imaging system LORHA provides part of the solution and its demonstrated capability of measuring the acoustic field inside a vehicle makes it an advanced tool for performing extensive studies of the acoustic transparency of car openings. This paper focuses on the methodology and recent operational results obtained within the tight collaboration established between METRAVIB RDS, its partner HUTCHINSON and well known car manufacturers.

The vehicle Heating, Ventilation and Air conditioning (HVAC) system is designed to meet both the safety and thermal comfort requirements of the passengers inside the cabin. The thermal comfort requirement, however, is highly subjective and is usually met objectively by carrying out time dependent mapping of parameters like the velocity and temperature at various in-cabin locations. These target parameters are simulated for the vehicle interior for a case of hot soaking and its subsequent cool-down to test the efficacy of the AC system. Typically, AC performance is judged by air temperature at passenger locations, thermal comfort estimation along with time to reach comfortable condition for human. Simulating long transient vehicle cabin for thermal comfort evaluation is computationally expensive and involves complex cabin material modelling.

Developing lightweight, stiff and crash-resistant vehicle body structures requires a balance between part geometry and material properties. High strength materials suitable for crash resistance impose geometry limitations on depth of draw, radii and wall angles that reduce geometric efficiency. The introduction of 3rd generation Advanced High Strength Steels (AHSS) can potentially change the relationship between strength and geometry and enable simultaneous improvements in both. This paper will demonstrate applicability of 3rd generation AHSS with higher strength and ductility to replace the 780 MPa Dual Phase steel in a sill reinforcement on the current Jeep Cherokee. The focus will be on formability, beginning with virtual simulation and continuing through a demonstration run on the current production stamping tools and press.

Crankshafts of motorcycles require high strength, high reliability and low manufacturing cost. Recently, a reduction of Pb content in the free-cutting steel, which is harmful substance, is required. In order to satisfy such requirements, we started the development of Pb-free free-cutting steel which simultaneously enabled the omission of the normalizing process. For the omission of normalizing process, we adjusted the content of Carbon, Manganese and Nitrogen of the steel. This developed steel can obtain adequate hardness and fine microstructure by air-cooling after forging. Pb-free free-cutting steel was developed based on Calcium-sulfur free-cutting steel. Pb free-cutting steel is excellent in cutting chips frangibility in lathe process. We thought that it was necessary that cutting chips frangibility of developed steel was equal to Pb free-cutting steel. It was found that cutting chips frangibility depend on a non-metallic inclusion's composition, shape and dispersion.

Previous applications of 980 XK steels in the automotive industry have been limited. However, to meet increased structural requirements of MVSS-301, AMC has incorporated 980 XK steel in the 1977 Gremlin and Hornet underbody rear sill subassemblies. This paper emphasizes how formability and spot weldability characteristics were optimized in order to meet the vehicular crashworthiness required in this structural application. Traditional mild steel design, forming, and spot welding procedures were successfully modified to utilize 980 XK. These modifications are practical and have been successfully incorporated in production operations.

Positive displacement pumps are key components in automotive and hydraulic fluid systems, often serving as the primary power source and a major source of noise in both on-highway and off-highway vehicles. Specifically, gerotor pumps are widely utilized in vehicle coolant, lubricating, and other fluid systems for both conventional and electric powertrains. This study introduces a novel method for predicting noise in gerotor pumps by combining a Computational Acoustics (CA) approach with a 3D Computational Fluid Dynamics (CFD) approach, both implemented in the Simerics–MP+ code. The CFD simulation includes the detailed transient motion of the rotors (including related mesh motion) and models the intricate cavitation/air release phenomena at varying pump speeds. The acoustic simulation employs a Ffowcs–Williams Hawkings (FW–H) integral formulation to predict sound generation and propagation based on the detailed flow field predictions from the CFD model.

The acoustics of automotive intake and exhaust systems is typically modeled using linear acoustics or gas-dynamics simulation. These approaches are preferred during basic sound design in the early development stages due to their computational efficiency compared to complex 3D CFD and FEM solutions. The linear acoustic method reduces the component being modelled to an equivalent acoustic two-port transfer matrix which describes the acoustic characteristic of the muffler. Recently this method was used to create more detailed and more accurate models based on a network of 3D cells. As the typical automotive muffler includes perforated elements and sound absorptive material, this paper demonstrates the extension of the 3D linear acoustic network description of a muffler to include the aforementioned elements. The proposed method was then validated against experimental results from muffler systems with perforated elements and sound absorptive material.

A mathematical simulation of the operation of a compressed-gas airbag system is developed. A system was built and tested, and the analysis is evaluated on the basis of these tests. Included in the study are nonideal gas effects, manifold and diffuser effects, bag stretch, bag leakage, and overpressurization of the passenger compartment. Interaction between a single rigid object and the bag is also considered. A correlation between bag pressure and the force it generates is obtained. This allows the development of an analytic model for determining the motion of a single rigid mass interacting with a dynamically inflating airbag mounted in a moving vehicle. An application of the model to study rebound of the occupant from the airbag is presented.

The aim of this work is to validate a BE numerical methodology to calculate how the acoustic properties of seats can affect the acoustic behaviour of the passenger compartment of a vehicle. An analytical model, based on the Delany and Bazley approach, was implemented in order to simulate the acoustic impedance of the foam-fabric system. This model has been validated with absorption coefficient measurements on a certain number of foam-fabric combinations. The calculated impedance was used as input for a BEM analysis of the interior cavity of a trimmed vehicle. The measured impedance of trimming components as floor carpet, door panels and parcel shelf were included into the cavity model. The acoustic field due to a known source with and without seats was calculated, in the frequency range 20-400 Hz: the calculated FRFs are in good agreement with the measured ones.

The focus of this paper is to develop an innovative vehicle layout and optimize vehicle body structure with the latest lightweight steel technologies, such as hydro-forming and hot stamping. Our BIW structure achieved a mass savings of 28 kg (−10%) compared to the mass of baseline BIW structure. (Base BIW : MD_Elantra)