Track 2 Session 8
2:20 to 3:20 p.m. Wednesday June 18, 2008

Reliability Improvement in Golf Car Development using Applied Reliability Methods

Over the past four years, E-Z-GO used applied reliability methods in the development of its new golf car. The methods were far ranging and touched every aspect of the development process. The goal was to provide customers with world class reliability, driving experience and value. E-Z-GO started with the basics with functional analysis, Voice of the Customer (VOC) and Design FMEAs. We defined our reliability target and then used advanced Weibull and Bayesian analysis to determine how best to meet these targets. We had to define the use environment and the design life expectancy and then design, prototype and validate each system, subsystem and component in order to prove the reliability of the design. Since there was no historical failure rate data on a variety of subsystems and components and many of the designs were entirely new, it was necessary to develop some assumptions, test those assumptions and then modify the assumptions as actual failures occurred. Once the failures were characterized then the tests were reset and rerun. The validation plan then became easier to confirm the reliability and have confidence that it was right. These methods also forced us to use reliability allocation in setting the targets for individual parts such that the entire vehicle met its target. The end result was an extremely reliable vehicle with customers demanding to obtain them even before production began.

Key Words: VOC, Functional Specifications, DFMEA, DVP&R, Bayesian, Weibull, Reliability Models, Reliability/Durability Testing