Shortening lead time while maintaining product quality requires planning the design process carefully. A simple, flexible process-planning mechanism for engine design, the Design Relationship Matrix, is used to achieve it. The matrix represents functional as well as structureal velationships between major components to assure that design information is reliably transmitted through the design organization. An investigation of an engine's design process was made in an automobile manufacturer. The authors identified areas for improvement, and synthesized mechanisms to achieve those improvements.