Inductive load driving device and driving method

• US 6,209,513 B1
• Filed: 12/31/1998
• Issued: 04/03/2001
• Est. Priority Date: 07/02/1996
• Status: Expired due to Fees

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Yoshida, Daisuke, Sakasai, Takashi, Akagi, Jiro
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US09/214,236
• Time in Patent Office: 824 Days
• Field of Search: 123/299, 123/490, 361/154
• US Class Current: 123/299
• CPC Class Codes: F02D 2041/2013 by using a boost voltage source
• CPC Class Codes: F02D 2041/2017 using means for creating a boost current or using reference switching
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for
• CPC Class Codes: H01F 7/1816 making use of an energy accumulator for relays H01H47/043
• CPC Class Codes: H02P 8/10 Shaping pulses for starting; Boosting current during starting

Abstract

An inductive load driving device in which the rise of load current at an initial stage of driving can be executed at high speed includes a plurality of step-up circuits (21, 31), for alternately applying a high voltage to the same inductive load within a predetermined period of time, to thereby allow each load current to rise at a high speed; a holding current output circuit (43), for applying a predetermined voltage to the same inductive load after the load current has risen, to thereby hold the load current at a predetermined value; a plurality of switching means (46, 47), adapted to be switched in such a manner that the respective outputs of the plurality of step-up circuits (21, 31) and the holding current output circuit (43) can be alternately connected to the same inductive load; and a control logic circuit (44), for switching the plurality of switching means (46, 47) in a predetermined sequence.

Claims

1. An inductive load driving device which is suitable for driving a same inductive load a plurality of times within a predetermined period of time and for executing that driving repeatedly, wherein said same inductive load is a respective solenoid, of a respective one of solenoid valves in fuel injectors for respective cylinders of an internal combustion engine, which controls a start time and a finish time of fuel injection by the respective one of the solenoid valves;

said inductive load driving device comprising;

a plurality of step-up circuits, each for alternately storing energy to step up a voltage to a high voltage and then applying the resulting high voltage to a respective same inductive load within a predetermined period of time, to allow a respective resulting load current to rise at high speed;

a single holding current output circuit, for applying a predetermined voltage to a respective same inductive load, after the respective resulting load current has been raised responsive to a respective one of said plurality of step-up circuits, to hold the respective resulting load current at a predetermined value;

a plurality of switching means, which are switchable in such a manner that a respective output of said plurality of step-up circuits and an output of said single holding current output circuit are alternately connected to a respective same inductive load; and

a control logic circuit for switching said plurality of switching means in a predetermined sequence; and

wherein said plurality of step-up circuits includes a first step-up circuit and a second step-up circuit;

wherein said first step-up circuit and said single holding current output circuit drive solenoids in the fuel injectors corresponding to respective cylinders in the internal combustion engine at times of pilot injection for the respective cylinder;

wherein said second step-up circuit and said single holding current output circuit drive, at each respective time of main injection, the same respective solenoid that was driven at a respective time of pilot injection for the respective cylinder;

wherein said plurality of switching means execute switching from/to outputs of said first step-up circuit at a time of a pilot injection to/from outputs of said second step-up circuit at a time of a main injection.

2. An inductive load driving device which is suitable for driving a same inductive load a plurality of times within a predetermined period of time and for executing the driving repeatedly, wherein said same inductive load is a respective solenoid, of a respective one of solenoid valves in fuel injectors for respective cylinders of an internal combustion engine, which controls a start time and a finish time of fuel injection by the respective one of the solenoid valves into a respective cylinder of said internal combustion engine, said inductive load driving device comprising:

a plurality of step-up circuits, each for alternately storing energy to step up a voltage to a high voltage and then applying the resulting high voltage to a respective same inductive load within a predetermined period of time, to allow a respective resulting load current to rise at high speed;

a single holding current output circuit, for applying a predetermined voltage to a respective same inductive load, after the respective resulting load current has been raised responsive to a respective one of said plurality of step-up circuits, to hold the respective resulting load current at a predetermined value;

a plurality of switching means which are switchable in such a manner that a respective output of said plurality of step-up circuits and an output of said single holding current output circuit are alternately connected to a respective same inductive load; and

a control logic circuit for switching said plurality of switching means in a predetermined sequence; and

wherein said plurality of step-up circuits includes a first step-up circuit and a second step-up circuit;

wherein said first step-up circuit and said single holding current output circuit drive a first solenoid in a fuel injector corresponding to a first cylinder in the internal combustion engine at a time of pilot injection for said first cylinder, and drive a second solenoid corresponding to a second cylinder, which injects fuel next after said first cylinder, at a time of main injection for said second cylinder, and those drivings at a time of a pilot injection and at a time of a main injection are repeated for other combinations of cylinders;

wherein said second step-up circuit and said single holding current output circuit drive the first solenoid, corresponding to said first cylinder, at a time of main injection for said first cylinder, and drive the second solenoid, corresponding to the second cylinder which injects fuel next after said first cylinder, at a time of pilot injection for said second cylinder, and those drivings at the time of a main injection and at a time of pilot injection are repeated for other combinations of cylinders; and

wherein said plurality of switching means executes switching from/to outputs of said first step-up circuit and said single holding current output circuit, at a time of pilot injection, to/from outputs of said second step-up circuit and said single holding current output circuit, at a time of main injection, or executes switching from/to outputs of said first step-up circuit and said single holding current output circuit, at a time of main injection, to/from outputs of said second step-up circuit and said single holding current output circuit, at a time of pilot injection.

3. An inductive load driving device which is suitable for driving a same inductive load a plurality of times within a predetermined period of time and for executing the driving repeatedly, wherein said same inductive load is a respective one of a plurality of phase coils in a step motor, said inductive load driving device comprising:

a plurality of step-up circuits, each for alternately storing energy to step up a voltage to a high voltage and then applying the resulting high voltage to a respective same inductive load within a predetermined period of time, to allow a respective resulting load current to rise at high speed;

a holding current output circuit, for applying a predetermined voltage to a respective same inductive load, after the respective resulting load current has been raised responsive to a respective one of said plurality of step-up circuits, to hold the respective resulting load current at a predetermined value;

a plurality of switching means which are switchable in such a manner that a respective output of said plurality of step-up circuits and an output of said holding current output circuit are alternately connected to a respective same inductive load; and

a level variation circuit for switching said plurality of switching means.

4. An inductive load driving device in accordance with claim 3, wherein said plurality of step-up circuits include a first step-up circuit and a second step-up circuit;

wherein said first step-up circuit allows an exciting current at a first level to rise at high speed;

wherein said second step-up circuit allows an exciting current at a second level to rise at high speed, and

wherein said holding current output circuit can provide an exciting current at a first level and at a second level and is provided for a respective one of said plurality of phase coils in said step motor; and

wherein said plurality of switching means switches respective outputs of said first step-up circuit and said second step-up circuit.

5. An inductive load driving device in accordance with claim 3, wherein a phase current in a respective phase coil in said step motor can be set at a plurality of levels;

wherein each respective one of said plurality of step-up circuits is provided for a respective phase coil in said step motor to allow an exciting current to rise at high speed at each level of said plurality of levels; and

wherein said holding current output circuit holds an exciting current for a respective phase coil at each level of said plurality of levels.

6. An inductive load driving device which is suitable for driving same inductive load a plurality of times within a predetermined period of time and for executing the driving repeatedly, said inductive load driving device comprising:

a plurality of step-up circuits, each for alternately storing energy to step up a voltage to a high voltage and then applying the resulting high voltage to a respective same inductive load within a predetermined period of time, to allow a respective resulting load current rise to a high speed;

a single holding current output circuit, for applying a predetermined voltage to a respective same inductive load, after the respective resulting load current has been raised responsive to a respective one of said plurality of step-up circuits, to hold the respective resulting load current at a predetermined value;

a plurality of switching means which are switchable in such a manner that a respective output of said plurality of step-up circuits and an output of said single holding current output circuit are alternately connected to a respective same inductive load; and

a control circuit for switching said plurality of switching means in a predetermined sequence.

7. An inductive load driving device in accordance with claim 6 wherein said same inductive load is a respective one of a plurality of inductive loads;

wherein said plurality of step-up circuits include a first step-up circuit and a second step-up circuit;

wherein said first step-up circuit and a single holding current output circuit drive a first one of said plurality of inductive loads during a first time period; and

wherein said second step-up circuit and said single holding current output circuit drive said first one of said plurality of inductive loads during a second time period.

8. An inductive load driving device in accordance with claim 7, wherein said first step-up circuit and said single holding current output circuit drive a second one of said plurality of inductive loads during a third time period;

and

wherein said second step-up circuit and said single holding current output circuit drive said second one of said plurality of inductive loads during a fourth time period.

9. An inductive load driving device in accordance with claim 7, wherein each of said plurality of inductive loads is a solenoid in a solenoid valve in a fuel injector for a respective cylinder of an internal combustion engine having a plurality of cylinders.

10. An inductive load driving device in accordance with claim 9, wherein each solenoid controls a start time and a finish time of fuel injection by the respective fuel injector.

11. An inductive load driving device in accordance with claim 10, wherein said first time period is a time of pilot injection for a first one of said plurality of cylinders, and wherein said second time period is a time of main injection for said first one of said plurality of cylinders.

12. An inductive load driving device in accordance with claim 7, wherein said first step-up circuit and said single holding current output circuit drive a second one of said plurality of inductive loads during a third time period;

and

wherein said second step-up circuit and said single holding current output circuit drive said second one of said plurality of inductive loads during a fourth time period;

wherein each of said plurality of inductive loads is a solenoid in a solenoid valve in a fuel injector for a respective cylinder of an internal combustion engine having a plurality of cylinders;

wherein each solenoid controls a start time and a finish time of fuel injection by the respective fuel injector.

13. An inductive load driving device in accordance with claim 12, wherein said first time period is a time of pilot injection for a first one of said plurality of cylinders;

wherein said second time period is a time of main injection for said first one of said plurality of cylinders;

wherein said third time period is a time of pilot injection for a second one of said plurality of cylinders; and

wherein said fourth time period is a time of main injection for said second one of said plurality of cylinders.