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Up to now Six Sigma has mainly been used for manufacturing. A Six Sigma approach was introduced in 2004 at Tenneco for transactional business This paper illustrates 2 examples where Six Sigma was successfully applied to improve the service quality. One first case is the improvement of a measurement system analysis [1]. In the exhaust system domain the acoustic performance of an exhaust system must meet the requirements in terms of drive-by noise of a vehicle and in terms of subjective sound. Therefore it is vital to measure the so-called “tailpipe noise” of an exhaust system with precision and reliability. Otherwise some iterations take place to confirm the data, or - more critical - an exhaust system design can be rejected when in reality it is just meeting the target curves and inversely, this could be accepted when the targets are not met.

Steel prices soared in the past years due to the increased demand on the Asian market. Due to difficult economic conditions of the automotive industry it is not possible to transfer expenses to the final customer. Reduction of steel is therefore required to compensate for higher steel prices. Whereas the underbody design space decreases in European vehicles, requirements are getting higher in terms of tailpipe noise and backpressure reduction. This leads to flat structures for mufflers which are integrated into the underbody to achieve as much inner volume for tailpipe noise damping as possible. That requires larger surfaces and results in a rise in costs, weight and radiated noise over surfaces. Additionally, original equipment manufacturers (OEM) require lightweight designs to meet carbon dioxide and consumption targets. Especially for Diesel applications the weight of exhaust systems is penalized by heavy Diesel particle filters.