Some thoughts about problem solving in a DMAIC framework

This paper explores the iterative nature of problem solving in the context of a complex system issue involving the interplay of hardware and software on a diesel engine. The case study illustrates how application of TRIZ and parameter design methodologies can greatly enhance and accelerate the problem-solving process. Slow- and high-amplitude oscillation of the entire vehicle powertrain under steady pedal position at idle is called "ringing", and similar behaviour under cruise-control conditions is called "hitching". TRIZ (a Russian acronym for Theory of Inventive Problem Solving) Anticipatory Failure Determination was used to discover root cause. Dr. Taguchi's parameter design was then used to find the appropriate levels for a variety of software variables to virtually eliminate the "hitching" condition. The use of TRIZ and robust engineering methods up-front in the design process, and the distinction between Six Sigma and design for Six Sigma are also discussed.