ULSAB-AVC Pursues Innovative Design Considerations for Packaging, Powertrain and Suspensions

DETROIT, MI, October 3, 2000 –- A platform approach, an innovative front end module and efficient front and rear suspension systems, packaged in a lightweight steel structure, are among the latest design developments in the global steel industry’s ULSAB-AVC (Advanced Vehicle Concepts) program.

Consistent with the auto industry’s shift to a systems design philosophy, these systems foster shorter development time through simultaneous engineering and early supplier involvement and optimize the assembly process and corresponding costs.

ULSAB-AVC is the most recent in the global steel industry’s series of initiatives to develop steel solutions to vehicle makers worldwide, which offer low cost mass reduction and performance improvement. A consortium of more than 30 of the world’s leading steel companies is leading and funding the study. Porsche Engineering Services, Inc., Troy, Mich., is conducting the design and engineering work and managing the technical aspects of the program.

At the onset of the ULSAB-AVC program, the consortium and Porsche defined two primary strategies to guide their efforts. The first was to create a lightweight steel platform that would optimize commonality of body structure parts between its two major vehicle targets: the European C-Class (typical example: Volkswagen Golf) and the North American PNGV-Class (based on the U.S. Partnership for a New Generation of Vehicles specifications).

The second major strategy was to optimize commonality of major components such as the suspension and powertrain systems of the two concept vehicles. In all cases, the stringent mass, carbon dioxide (CO2)emissions and safety targets and affordability parameters would drive decisions on common parts.

Front End Module

An excellent example of advanced modularity is ULSAB-AVC’s front end. The engine bay package layout is based on a fully operational front-end module that incorporates engine, gearbox, front suspension, radiator and steering rack, mounted on a single cradle and bolted to the body structure. This design allows for removal of the entire powertrain/suspension system in a single unit for servicing. For this purpose, Porsche will incorporate quick-release connections for power, heating, hydraulics and steering column.

Engine and Gearbox Package

Mass reduction objectives and stringent safety requirements for occupant safety are driving the engine/gearbox layout. To achieve safety requirements in the unique front end modular system, the Porsche design positions the engine behind the gearbox, allowing the powertrain to move rearward into a structural tunnel during a crash to minimize footwell intrusion into the passenger compartment. This positioning also contributes to better load distribution in ULSAB-AVC than is typical in front-wheel drive vehicles, and, thus, could facilitate the potential elimination of the stabilizer bar, for further mass savings. It also contributes to mass reduction due to a significantly shortened exhaust routing.

Consistent with the vehicle mass target and requirements for acceleration, cruising speed and CO2 emissions, the AVC consortium specified two engine versions (gasoline and diesel). Porsche chose a narrow, V3, 1200 cc engine concept. The reduced width of this engine type provides the clearance between the engine and the tunnel during a crash.

In packaging the vehicles during this preliminary design, Porsche paid special attention to positioning of the front occupants and the pedals to ensure adequate clearance between the occupants and tunnel. Specialists also carried out detailed studies of other important packaging areas such as steering wheel and rear passenger positions. Porsche put the fuel tank in a secure area underneath the rear seat forward of the rear suspension. The fuel tank capacity is 40 liters.

Suspension Concepts

A steel, double wishbone front suspension system allows for integration of the suspension into the front cradle, yet does not require disassembly of the strut to remove the engine cradle/suspension module for servicing. There also is no need to readjust the suspension alignment after engine servicing. The suspension uses a single leaf spring, eliminating the need for a shock/spring tower. This design complements the engine bay package.

Porsche developed a unique steel twistbeam for the rear suspension. With a four-point mounting, the suspension system allows for ease of assembly from underneath the vehicle and contributes to cost and mass optimization.

The concepts Porsche has developed for ULSAB-AVC thus far are preliminary, and as the program progresses, Porsche designers will make additional modifications and adjustments, as necessary.

Scheduled for completion in fall 2001, ULSAB-AVC will present advanced concepts to help automakers use steel more efficiently and provide a steel-based structural platform for achieving:

  • anticipated crash safety requirements for 2004

  • significantly improved fuel efficiency

  • optimized environmental performance regarding emissions, source reduction and

  • recycling, and, high volume manufacturability at affordable cost.

The Automotive Applications Committee (AAC) is a subcommittee of the Market Development Committee of AISI and focuses on advancing the use of steel in the highly competitive automotive market. With offices and staff located in Detroit, cooperation between the automobile and steel industries has been significant to its success. This industry cooperation resulted in the formation of the Auto/Steel Partnership, a consortium of DaimlerChrysler, Ford and General Motors and the member companies of the AAC.

This release and other steel-related information are available for viewing and downloading at American Iron and Steel Institute/Automotive Applications Committee’s website at http://www.autosteel.org.

American Iron and Steel Institute/
Automotive Applications Committee:
AK Steel Corporation
Bethlehem Steel Corporation
Dofasco Inc.
Ispat Inland Inc.
National Steel Corporation
Rouge Steel Company
Stelco Inc.
United States Steel Corporation
WCI Steel, Inc.
Weirton Steel Corporation