Computers and Control Systems: Description and Operation

The diesel engine control system provides microprocessor control of injection timing, the EGR system and engine pre-heating, and links the fuel injection system to the active check control which monitors various vehicle systems and displays system status on an instrument panel mounted display. System components include an VP-20 control module, injection pump mounted timing (pulse) valve, fuel injectors with integral pulse and duration sensors, a separate pre-heating control unit and glow plugs for each cylinder, throttle position, engine speed, TDC and coolant temperature sensors, EGR vacuum switching valve and altitude compensation control.
The VP-20 control module monitors engine and vehicle operating conditions through a group of sensors, computes the ideal injection pump timing and EGR quantity based upon this information and controls injection pump and EGR valve operation accordingly. In addition, the system has a diagnostic capability which will light the ``Injection'' lamp in the active check control panel when a system malfunction is detected. The pre-heat controller monitors engine coolant temperature and current flow through the glow plugs in order to aid cold starting and provide acceptable cold engine driveability.