System Level Block Diagram of Fuel Injector Controller

This subsystem contains all circuitry that will regulate power to the microprocessor, sensors, and sparks subsystems.  This would include such circuits as voltage regulators, converters, line conditioners, and oscillators.

This subsystem contains the physical sensors and the interfacing to the microprocessor.  Any analog to digital converters, filters, and scaling circuitry would be contained in this system.

uC / Software:
This subsystem contains the microprocessor, address decoding circuitry, and program EPROM.  The EPROM will contain the code for the controller, in which a full program flow chart is shown in Fig I.  This subsystem can be looked upon as the brains of the operation, because all the inputs and outputs will be maintained from here.  Manipulating the control outputs based on the inputs received from the sensor subsystem attains the control of the engine.

The spark subsystem contains the ignition coils.  It accepts a timing input from the microprocessor and fires the spark plugs accordingly.

In this subsystem, the injectors, fuel pump, and timing/sequence circuitry are contained.  The function of the system is to control the injector sequence and duration of fuel spray into the pre-combustion chamber.  During startup, the fuel relay pump is turned on prior to starting the engine so that the fuel line is pressurized.  This allows pre-prime of the engine prior to startup.

This subsystem is responsible to maintain the reliability and working condition of the controller.   Two inputs, power and error detection, allow the driver to provide the controller with immediate attention.  This system also maintains the trouble shooting routine that tests the controller to ensure working condition, and if not, return the error code corresponding to the detected problem.

Automatic Transmission:
This system contains two power transistors that will be used to control the up and down sequence of the transmission.  Two inputs from the microprocessor will determine when the transmission is to shift.

This subsystem will maintain the link between the controller and the outside world.  A serial communication port will be used to establish a link to a PC for reading of diagnostic codes and real-time calculations.  The EPROM look-up table is also contained in this subsystem because it can be exchanged to incorporate other desired engine characteristic.

Key to Labels:
    1) Power to Sensor Subsystem
    2) Power to Microprocessor
    3) Power to Spark Ignition System
    4) Sensor Inputs to Microprocessor
    5) Timing for Sparks
    6) Fuel Relay Control Signal
    7) Injection timing Signal
    8) Revolution Limiting Signal
    9) Power Detect Signal
    10) Error Detect Signal
    11) Diagnostic Start Input
    12) Transmission Shift Up
    13) Transmission Shift Down
    14) Lookup Table Signal
    15) Serial Port Communication