Find the right tone

For a long time, a product’s functionality has not been the only key factor for its success - it also has to sound like a reliable, quality product. The motor of a power window unit, for example, should give off a powerful whir, and not whine or squeak - otherwise it would give the impression that it is overstrained by the weight of the glass.

In the past, noises and vibrations were seen as quality errors. Today they are viewed as mechanical system parameters, and are incorporated or optimized in development plans.

Bosch is working worldwide on improving noise quality

Bosch investigates and optimizes “Noise Vibration Harshness (NVH)” worldwide - conducting research in sounds, oscillations and vibrations.

In several locations in Europe, Japan and the U.S., researchers investigate the sounds produced by fuel injection nozzles, power window units, windshield wipers, starters, alternators and brakes.

One of the largest locations for Bosch NVH research is in Farmington Hills, Michigan, in the U.S.

Bosch acoustics laboratory in Farmington Hills
One of the crucial requirements for a perfect product sound is that the model calculations should have as precise a forecast accuracy as possible. Components whose acoustic qualities were perfected in the laboratory should also have an optimal sound on the road.

A special NVH procedure from Farmington Hills

Like the development process for improving the function, strength and durability of a product, the NVH process uses simulation, calculation and experimentation - but on a much more complex level.

A special “quality guarantee process” was defined in Farmington Hills, which establishes the exact procedure and construction targets for simulations, experiments, the test bench and vehicle measurements.

Reality is simulated on the test bench.

With the aid of single and double axle chassis dynamometers, vehicles of any size, from compact cars to the largest sport utility vehicles, can be tested on the varying demands made by road traffic.

The test benches are located in air conditioned rooms. The engineers can vary the temperature from ten degrees below to 50 degrees above zero Celsius, and create a relative humidity ranging from zero to 95 percent.
The walls and ceilings of the laboratories are equipped with sound absorbing material for acoustic measurements. The floors are fitted out like a roadway.

This newly furnished, 1500 square meter NVH laboratory plays a very large part in reducing development times. Thanks to simulation precision, product designers can integrate laboratory calculations directly into their work, using them to modify the object during the design process.