Energy recovery circuit configuration for solenoid injector driver circuits

• US 6,175,484 B1
• Filed: 03/01/1999
• Issued: 01/16/2001
• Est. Priority Date: 03/01/1999
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Lee, Chien C., Davis, Errol W., Love, William J., Caruthers, Michael A.
• Primary Examiner(s): FLEMING, FRITZ M
• Application Number:
  US09/259,942
• Time in Patent Office: 687 Days
• Field of Search: 361/152-156, 361/159, 361/160, 361/191
• US Class Current: 361/159
• CPC Class Codes: F02D 2041/2006 by using a boost capacitor
• CPC Class Codes: F02D 2041/2041 for controlling the current in the free-wheeling phase
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils

Abstract

A circuit configuration wherein a plurality of solenoid driver circuits are all coupled together such that the high voltage supply associated with one driver circuit is connected in parallel with the high voltage supply of another driver circuit. Each driver circuit includes a high voltage select switch, a select switch, and a modulation switch, all of which switches are coupled to and controlled by an electronic controller such that back EMF created by the solenoid coil in each respective driver circuit can be recaptured by charging the high voltage supply associated with that driver circuit. This recaptured energy can then be utilized to not only provide current flow to the solenoid coil associated with that particular driver circuit, but such energy can likewise be utilized to recharge any plurality of the other high voltage supplies associated with the other driver circuits, even while the solenoid coils of such driver circuits are being powered by their respective high voltage supply.

Claims

1. An apparatus for recovering solenoid coil energy in a solenoid driver circuit comprising:

a first solenoid driver circuit including a solenoid coil for controlling the operation of an actuator;

a high voltage capacitor coupled to said solenoid coil for providing current flow thereto;

a high voltage select switch connecting said capacitor to said solenoid coil;

a low voltage supply coupled to said solenoid coil;

a select switch connecting said low voltage supply to said solenoid coil;

a flyback current path connecting said solenoid coil with said high voltage capacitor; and

an electronic controller coupled to said high voltage select switch and to said select switch and being operable to output control signals thereto;

a second solenoid driver circuit including a solenoid coil for controlling the operation of an actuator; and

a high voltage capacitor coupled to said solenoid coil for providing current flow thereto and a flyback current path connecting said solenoid coil with said high voltage capacitor; and

the high voltage capacitor of said first driver circuit being connected in parallel to the high voltage capacitor of said second driver circuit;

wherein the current generated by the back EMF of the solenoid coil associated with said second driver circuit is operable to charge the high voltage capacitor of said first driver circuit at a time when the high voltage capacitor of said first driver circuit is providing current flow through the solenoid coil of said first driver circuit.

2. The apparatus, as set forth in claim 1, wherein the current generated by the back EMF of the solenoid coil associated with said second driver circuit is operable to charge the high voltage capacitor of said first driver circuit at a time when the high voltage capacitor of said first driver circuit is not providing current flow through the solenoid coil of said first driver circuit.

3. The apparatus, as set forth in claim 1, wherein said first driver circuit include a modulation switch connected in series with said solenoid coil, said modulation switch being operable between an open and a closed position, said electronic controller selectively outputting signals to said high voltage select switch, said select switch, and said modulation switch to control current flow through the solenoid coil of said first driver circuit at at least one of a time when said solenoid coil does not have sufficient current flow therethrough to operate the actuator and a time when said solenoid coil has sufficient current flow therethrough to operate the actuator, said electronic controller modulating the current through said solenoid coil between first and second predetermined current levels, said first and second predetermined current levels being less than the current level required to allow said solenoid coil to operate the actuator, the back EMF created in said solenoid coil during modulation being used to charge the high voltage capacitor of said first driver circuit at a time when said modulation switch is in its open position.

4. The apparatus, as set forth in claim 1, wherein said second driver circuit includes a high voltage select switch connecting said high voltage capacitor to said solenoid coil;

a low voltage supply coupled to said solenoid coil;

a select switch connecting said low voltage supply to said solenoid coil; and

an electronic controller coupled to said high voltage select switch and to said select switch and being operable to output signals thereto;

the electronic controller coupled to said second driver circuit selectively outputting signals to the high voltage select switch and the select switch of said second driver circuit for controlling the operation of said solenoid coil between a first condition wherein said high voltage capacitor provides current flow through said solenoid coil, a second condition wherein said low voltage supply provides current flow through said solenoid coil, and a third condition wherein no current flow is provided through said solenoid coil by either said high voltage capacitor or said low voltage supply;

the back EMF created in the solenoid coil of said second driver circuit during the time current flow is provided through said solenoid coil causing current to flow through said flyback current path to recharge the high voltage capacitor of said second driver circuit to a predetermined level at a time when no current flow is provided through said solenoid coil by said high voltage capacitor or said low voltage supply;

the current generated by the back EMF of the solenoid coil of said second driver circuit charging the high voltage capacitor of said first driver circuit.

5. The apparatus, as set forth in claim 1, wherein the current generated by the back EMF of the solenoid coil associated with said first driver circuit charges the high voltage capacitor of said second driver circuit at at least one of a time when the high voltage capacitor of said second driver circuit is providing current flow through the solenoid coil of said second driver circuit and a time when the high voltage capacitor of said second driver circuit is not providing current flow through the solenoid coil of said second driver circuit.

6. The apparatus, as set forth in claim 4, wherein said second driver circuit includes a modulation switch connected in series with said solenoid coil, said modulation switch being operable between an open and a closed position, said electronic controller selectively outputting signals to said high voltage select switch, said select switch, and said modulation switch to control current flow through the solenoid coil of said second driver circuit at a time when said solenoid coil does not have sufficient current flow therethrough to operate the actuator, said electronic controller modulating the current through said solenoid coil between first and second predetermined current levels, said first and second predetermined current levels being less than the current level required to allow said solenoid coil to operate the actuator, the back EMF created in said solenoid coil during modulation being used to charge the high voltage capacitor of said second driver circuit at a time when said modulation switch is in its open position.

7. The apparatus, as set forth in claim 4, wherein the electronic controller associated with said second driver circuit is the same electronic controller associated with said first driver circuit.

8. The apparatus, as set forth in claim 1, including a plurality of additional solenoid driver circuits, each additional solenoid driver circuit including a solenoid coil for controlling the operation of an actuator and a high voltage capacitor coupled to said solenoid coil for providing current flow thereto, all of the high voltage capacitors of said additional driver circuits being coupled together such that the high voltage capacitor associated with one of said additional driver circuits is connected in parallel with the high voltage capacitor associated with another of such additional driver circuits, and one of said additional high voltage capacitors being connected in parallel to the high voltage capacitor of said second driver circuit, the current generated by the back EMF of the solenoid coil associated with said first driver circuit charging at least some plurality of the high voltage capacitors of said additional driver circuits at a time when no current flow is provided through the solenoid coil of said first driver circuit by said high voltage capacitor or said low voltage supply.

9. The apparatus of claim 1, wherein said electronic controller is operable to selectively output signals to the high voltage select switch and the select switch of said first driver circuit for controlling the operation of said solenoid coil between a first condition wherein said high voltage capacitor provides current flow through said solenoid coil, a second condition wherein said low voltage supply provides current flow through said solenoid coil, and a third condition wherein no current flow is provided through said solenoid coil by either said high voltage capacitor or said low voltage supply;

wherein the back EMF created in the solenoid coil of said first driver circuit during the time current flow is provided through said solenoid coil causing current to flow through said flyback current path to recharge the high voltage capacitor of said first driver circuit to a predetermined level at a time when no current flow is provided through said solenoid coil by said high voltage capacitor or said low voltage supply; and

wherein the current generated by the back EMF of the solenoid coil associated with said first driver circuit is operable to charge the high voltage capacitor of said second driver.

10. An apparatus for recovering solenoid coil energy in a solenoid driver circuit comprising:

a first solenoid driver circuit including at least one solenoid coil for controlling the operation of an actuator;

a high voltage supply coupled to said at least one solenoid coil for providing current flow thereto;

a high voltage select switch connecting said high voltage supply to said at least one solenoid coil;

a low voltage supply coupled to said at least one solenoid coil;

a select switch connecting said low voltage supply to said at least one solenoid coil;

a modulation switch connected in series with said at least one solenoid coil;

a flyback current path connecting said at least one solenoid coil with said high voltage supply; and

an electronic controller coupled to said high voltage select switch, said select switch, and said modulation switch and being operable to output control signals thereto to control the opening and closing of said switches;

a second solenoid driver circuit including at least one solenoid coil for controlling the operation of an actuator;

a high voltage supply coupled to said at least one solenoid coil for providing current flow thereto and a flyback current path connecting said solenoid coil with said high voltage supply;

the high voltage supply of said first driver circuit being connected in parallel to the high voltage supply of said second driver circuit;

said electronic controller selectively outputting signals to said high voltage select switch, said select switch, and said modulation switch of said first driver circuit to provide current flow through said at least one solenoid coil sufficient to allow said at least one solenoid coil to operate the actuator for a predetermined time;

said electronic controller operable to selectively output signals to said high voltage select switch, said select switch, and said modulation switch of said first driver circuit to control the current flow through said at least one solenoid coil at a current level which is not sufficient to allow said at least one solenoid coil to operate the actuator for a predetermined time;

the at least one solenoid coil of said first driver circuit generating back EMF and causing current to flow through said flyback current path to recharge the high voltage supply of said first driver circuit to a predetermined level at a time when the current flow through said at least one solenoid coil is not sufficient to allow said at least one solenoid coil to operate the actuator;

the current generated by the back EMF of the at least one solenoid coil of said second driver circuit operable to charge the high voltage supply of said first driver circuit when said first driver circuit is providing current flow to said solenoid coil.

11. The apparatus, as set forth in claim 10, wherein the at least one solenoid coil of said second driver circuit is operable between a first condition wherein current flow through said at least one solenoid coil is sufficient to operate the actuator, and a second condition wherein the current flow through said solenoid coil is not sufficient to operate the actuator, the current generated by the back EMF of the at least one solenoid coil of said first driver circuit charging the high voltage supply of said second driver circuit at a time when current flow through the at least one solenoid coil of said second driver circuit is at least one of sufficient to operate the actuator and not sufficient to operate the actuator.

12. An apparatus for recovering solenoid coil energy in a solenoid driver circuit comprising:

a first solenoid driver circuit including a solenoid coil for controlling the operation of an actuator;

a high voltage capacitor coupled to said solenoid coil for providing current flow thereto;

a high voltage select switch connecting said capacitor to said solenoid coil;

a low voltage supply coupled to said solenoid coil for providing current flow thereto;

a select switch connecting said low voltage supply to said solenoid coil;

a modulation switch connected in series with said solenoid coil, said modulation switch being operable between an open and a closed position;

a flyback current path connecting said solenoid coil with said high voltage capacitor; and

an electronic controller coupled to said high voltage select switch, said select switch, and said modulation switch and being operable to output control signals thereto;

a second solenoid driver circuit including a solenoid coil for controlling the operation of an actuator;

a high voltage capacitor coupled to said solenoid coil for providing current flow thereto; and

a flyback current path connecting said solenoid coil with said high voltage capacitor;

the high voltage capacitor of said first driver circuit being connected in parallel to the high voltage capacitor of said second driver circuit;

said electronic controller operable to selectively output signals to the high voltage select switch, the select switch, and said modulation switch of said first driver circuit for controlling the operation of said solenoid coil between a first condition wherein said high voltage capacitor provides current flow through said solenoid coil, a second condition wherein said low voltage supply provides current flow through said solenoid coil, and a third condition wherein no current flow is provided through said solenoid coil by said high voltage capacitor or said low voltage supply;

said electronic controller operable to selectively output signals to said high voltage select switch, said select switch, and said modulation switch to control current flow through the solenoid coil of said first driver circuit at a time when the current flow through said solenoid coil is being provided by said high voltage capacitor or said low voltage supply, said electronic controller modulating the current through said solenoid coil between first and second predetermined current levels;

the solenoid coil of said first driver circuit operable to generate back EMF during the modulation of the current through said solenoid coil between said first and second predetermined current levels, the back EMF created in said solenoid coil during modulation being used to charge the high voltage capacitor of said first driver circuit at a time when said modulation switch is in its open position;

the current generated by the back EMF of the solenoid coil of said first driver circuit operable to charge the high voltage capacitor of said second driver circuit at a time when said high voltage capacitor is providing current flow to said second driver circuit.

13. An apparatus for recovering solenoid coil energy in a solenoid driver circuit comprising:

a first solenoid driver circuit including a plurality of solenoid coils, each solenoid coil controlling the operation of a particular actuator;

a high voltage supply coupled to each of said solenoid coils for providing current flow thereto;

a high voltage select switch connecting said high voltage supply to said plurality of solenoid coils;

a low voltage supply coupled to said plurality of solenoid coils;

a select switch connecting said low voltage supply to said plurality of solenoid coils;

a modulation switch connected in series with each of said solenoid coils;

a flyback current path connecting each of said plurality of solenoid coils with said high voltage supply; and

an electronic controller coupled to said high voltage select switch, said select switch, and said modulation switches and being operable to output control signals thereto to control the opening and closing of said switches;

a second solenoid driver circuit including at least one solenoid coil for controlling the operation of at least one actuator;

a high voltage supply coupled to said at least one solenoid coil for providing current flow thereto and a flyback current path connecting said at least one solenoid coil with said high voltage supply;

the high voltage supply of said first driver circuit being connected in parallel to the high voltage supply of said second driver circuit;

said electronic controller operable to selectively outputting signals to said high voltage select switch, said select switch, and said modulation switches of said first driver circuit to selectively provide current flow through said plurality of solenoid coils sufficient to allow each of said solenoid coils to operate its particular actuator for a predetermined time;

said electronic controller operable to selectively output signals to said high voltage select switch, said select switch, and said modulation switches of said first driver circuit to selectively provide current flow through said plurality of solenoid coils at a current level which is not sufficient to allow each of said solenoid coils to operate its particular actuator for a predetermined time;

each of said solenoid coils associated with said first driver circuit generating back EMF and causing current to flow through its respective flyback current path to charge the high voltage supply of said first driver circuit to a predetermined level at a time when the current flow through each of said respective solenoid coils is not sufficient to allow each of said solenoid coils to operate its particular actuator;

the current generated by the back EMF of each of said solenoid coils of said first driver circuit operable to charge the high voltage supply of said second driver circuit at a time when said high voltage supply is providing current to said at least one solenoid coil of said second solenoid driver circuit.

14. A circuit for controlling a plurality of operations effected through a plurality of solenoids comprising first and second driver circuit portions and a low voltage source, each of said first and second driver circuit portions including a solenoid controlled portion and an initiating portion, each initiating portion including a high voltage capacitor, each solenoid controlled portion including a solenoid coil, a current control portion, and a current sensing portion, said current control portion operable to generate current command signals under predetermined conditions, said high voltage capacitor of each of said first and second circuit portions being operatively connectable to the solenoid coil of such circuit portion in response to a current command signal to supply high voltage thereto and disconnectable from said solenoid coil when said current sensing portion of such circuit portion senses current through said solenoid exceeding a respective first predetermined level, said solenoid coil of each of said first and second circuit portions being operatively connectable to said low voltage source when said current sensing portion of such circuit portion falls below a respective second predetermined level and disconnectable from said low voltage source when said current sensing portion of such circuit portion exceeds said respective first predetermined level, said solenoid coil of each of said first and second circuit portions having a circuit connection back to said high voltage capacitor of such circuit portion to supply charging current thereto from said solenoid coil when either said high voltage supply from said high voltage capacitor is disconnected or said low voltage source is disconnected from said solenoid coil, said high voltage capacitors of said first and second circuit portions being connected to one another in parallel, whereby said high voltage capacitors of both said first and second circuit portions are charged with energy created in the solenoid coil inductances of said first and second circuit portions when charging current is supplied by either of said solenoid coils of said first or second circuit portions, said charging operable to occur when one of the high voltage capacitors is supplying high voltage to said solenoid coil.

15. An apparatus for recovering solenoid coil energy in a solenoid driver circuit, comprising:

a first capacitor operable to store a relatively high voltage;

a first solenoid coil operable to be switchably coupled with the first capacitor;

a first flyback current path coupling the first solenoid coil with the first capacitor and operable to couple back EMF of the first solenoid coil with the first capacitor;

a second capacitor coupled in parallel with the first capacitor, the second capacitor operable to store a relatively high voltage;

a second solenoid coil operable to be switchably coupled with the second capacitor; and

a second flyback current path coupling the second solenoid coil with the second capacitor and operable to couple back EMF of the second solenoid coil with the second capacitor and the first capacitor, the back EMF of the second solenoid coil operable to charge the first capacitor when the first capacitor is discharging through the first solenoid coil.