This paper presents the design and development of the Detroit Diesel Electronic Control system (DDEC) for heavy duty diesel engines. DDEC is a microprocessor controlled electronic unit injection-engine governing system. The application of microprocessor technology to the unit injection system provides both precision and flexibility in fuel injection timing and metering events through the use of solenoid operated unit injectors. The on-board diagnostic capabilities of the microprocessor provide for system self-diagnostics and, combined with engine oil and water system sensors, offer engine protection diagnostics.
The design and development of the solenoid operated unit injector, the selection of the sensors, and the engine control philosophy are discussed. Injector solenoid performance characteristics and engine data on cold starting, cold smoke, and transient smoke are presented in illustration of design decisions.