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Leak detection of vehicle cabin interiors is an important quality inspection phase that typically has been handled with various time consuming, or potentially product damaging techniques. Leak detection in tank or pressure vessel applications is almost always a concern for gas or fluid containment in vehicles and in many other industries. Numerous techniques exist for the detection of leaks in these and other types of structures. When testing is required in a production environment, often the speed of leak detection is very important if all samples must be tested. The use of several ultrasound based methods for leak detection in vehicle cabins and pressure vessel applications is presented here. Ultrasound waves are typically classified as having spectral content greater than 20 kHz. In the case of leak detection in a production environment, frequently the ultrasonic spectrum is largely free from background noise content that dominates the audible spectrum.

Tire Sound Quality is an increasingly important factor for customer satisfaction within the replacement tire market. Manufacturers who compete in this market must be capable of predicting a driver's perception of tire noise as early in the design process as possible in order to reduce development time and cost. Typical methods for tire noise evaluation each have limitations that require improvement. Subjective in-vehicle testing is generally an effective method for predicting driver perception, but it is vehicle specific, time consuming, and requires complete sets of tires for testing. Traditional single tire (component level) test methods measure overall tire noise levels, but do not always provide information relevant to a driver's perception of tire noise in a vehicle. Detailed noise path analysis techniques are cost prohibitive due to the amount of time and effort required to characterize each vehicle and the multitude of vehicles that exist.

In recent years, the perceived quality of powered seat adjusters based on their sound during operation has become a primary concern for vehicle and seat manufacturers. Historical noise targets based on overall dB(A) at the occupant's ear have consistently proved inadequate as a measure of the sound quality of a seat adjuster. Significant effort has been devoted to develop alternative sound quality metrics that can truly discriminate between “good” and “bad” seat adjusters. These new metrics have been successfully applied for some years by product development engineers in test labs. However, in the assembly plant the sound quality of the seat adjuster is still assessed subjectively by an operator at the end of the assembly line. The main problem with this approach is not only the lack of consistency and repeatability across large samples of seat tracks, but also the fact that the only feedback provided from the end-of-line to the product development team is of subjective nature.

Two years after the start of production, some members in a family of power seat adjusters developed an intermittent loud squeal sound when operated in the vehicle. An exhaustive and comprehensive engineering analysis identified the noise source to be primarily a single component in the seat track which was excited under specific conditions to vibrate in its free - free natural resonant frequency mode. The component was identified as the horizontal lead screw which vibrated under stick-slip principles against mating hardware. The noise was not reproducible in any consistent way; therefore, it was not readily detectable with 100% serial testing. Several solutions were enacted for controlling the problem in the short term while an investigation to the root cause was completed. Three long term solutions which addressed the root cause were pursued in parallel up to the production release of the best solution.