Multiplexed electronic fuel injection control system

An electronic fuel injection control system of the type having a plurality of fuel injection valves, each valve operated by an electromagnetic solenoid, the control system comprising:

• at least one driver circuit for supplying power to a drive terminal of the solenoids, the driver circuit including a current limiting circuit for safeguarding the system from excessive current surges;
• at least one control circuit for controlling the current flow through a selected solenoid;
• a first array of switches electrically connected in series between the power source and the first terminals of the solenoids;
• and
• a second array of switches electrically connected in series between the control circuits and a second terminal on the solenoids;
• the first and second arrays of switches being interconnected among the power source, the at least one control circuit, and the solenoids so that closure of any single switch from each array of switches uniquely selects and energizes a single solenoid.

An electronic fuel injection control system of the type having a plurality of fuel injection valves, each valve operated by an electromagnetic solenoid, the control system comprising:

• at least one driver circuit for supplying power to a drive terminal of the solenoids, the driver circuit including means for providing continuous current flow through a selected solenoid throughout the fuel injection cycle;
• at least one control circuit for controlling the current flow through the selected solenoid, the control circuit being configured to operate by pulse width modulating the voltage applied across the selected solenoid to effect a predetermined current flow therethrough;
• a first array of transistor switches electrically connected in series between the at least one driver circuit and the drive terminals of the solenoids;
• a second array of switches electrically connected in series between the control circuits and control terminals of the solenoids;
• the first and second arrays of switches being interconnected among the at least one driver circuit, the at least one control circuit, and the solenoids so that closure of any single switch from each array of switches uniquely selects and energizes a single solenoid;
• and
• a central computer having output signals for selectively operating the individual transistor switches of each array of switches.

An electronic fuel injection control system of the type having a plurality of fuel injection valves, each valve operated by an electromagnetic solenoid, the control system comprising:

• at least one driver circuit for supplying power to the solenoid during a fuel injection cycle, the driver circuit including means for collapsing the magnetic field of a selected solenoid and, thus, rapidly dissipating the energy stored therein at the end of the fuel injection cycle;
• at least one control circuit for providing precision control of the current flow through the selected solenoid during the fuel injection cycle;
• a first array of switches electrically connected in series between the power source and the first terminals of the solenoids;
• and
• a second array of switches electrically connected in series between the control circuits and a second terminal on the solenoids;
• the first and second arrays of switches being interconnected among the power source, the at least one control circuit, and the solenoids so that closure of any single switch from each array of switches uniquely selects and energizes a single solenoid.