Does Your Car Rattle and Squeak? That's Good, Says World Congress Author

    WARRENDALE, Pa., Feb. 8 Most consumers want a comfortable,
quiet automobile ride. Governments and environmentalists want a reduction in
vehicle noise. So why haven't the automakers engineered a completely noiseless
car?

    "Cars have to be noisy," explains Hans Martin Gerhard, Porsche AG,
Germany, and author of SAE paper "The Perfectly Silent Car-an Engineering
Goal?" Gerhard will present his theories on the subject at the SAE 2001 World
Congress, March 5-8 in Cobo Center, Detroit, Michigan.

    "Noises in the passenger compartment are necessary because they transmit
messages to the driver -- although some of them may be annoying," admits
Gerhard. "Low interior noise levels can cause the driver to underestimate
driving speed because they lose `acoustical contact' with the engine."

    Lack of exterior noise can also be dangerous, according to Gerhard. He
says that cars would need to be silenced to solve dense automotive traffic
noise, but at what risk to the elderly, children and blind? And what about
consumers who expect driving to be a thrilling and acoustical experience?

    "Customers appreciate a car for the emotions it conveys," says Gerhard.
"Since these expectations are so closely linked with acoustic properties, the
answer to the question of a completely noiseless car must be `no'."

    "In the future, acoustical experts will need to transform noise into
acoustic information," says Gerhard. "We'll need new design methods to allow
sound to be engineered in a more precise and sensitive way. We must also take
up the challenge of traffic noise if we want the automobile to remain a
desirable product."

    In his paper, he notes that the International Standards Organization (ISO)
has prescribed noise-reducing measures that would ultimately lead to cars
silent enough to reduce overall traffic noise. However, Gerhard concludes the
ISO 362 approach is not practical because of unduly high workload and
financial costs.