Improving a Vehicle Theft Deterrent System's Communication Using Design for Six Sigma (DFSS)

General Motors' vehicles are designed with an engine immobilizer theft deterrent system. An engine immobilizer theft deterrent system only allows starting of the vehicle engine after assuring the key is the correct key. The communication link from the vehicle to the key is a critical interface for the starting of the engine. This communication link must be reliable. The vehicle theft deterrent system's ability to communicate between the vehicle and transponder in the key is measured by the coupling factor. There are a number of physical interfaces that affect the coupling factor.

The focus of this work is to understand the physics and critical design parameters involved in achieving optimal coupling factor to improve the first time quality in future designs. Achieving this objective will lead to designs robust to variances in material and packaging design and result in less testing.

The process used in the past on these systems was the Design-Test-Fix approach. This method resulted in very expensive late design changes. Using an orthogonal array to understand the factors critical to coupling factor was a new approach for this system.

An L18 orthogonal array was utilized to assess various factors and their associated levels. A series of L18 orthogonal arrays were utilized to assess various factors with their associated levels and their impact on coupling factor in the face of compounded noise factors. The last L18 in the series is the focus of this paper.