Fuel injector control system for cylinder injection type internal combustion engine

• US 5,934,258 A
• Filed: 12/15/1997
• Issued: 08/10/1999
• Est. Priority Date: 04/18/1997
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Watanabe, Tetsushi
• Primary Examiner(s): Solis, Erick R.
• Application Number:
  US08/990,776
• Time in Patent Office: 603 Days
• Field of Search: 361/154, 123/490, 123/299
• US Class Current: 123/490
• CPC Class Codes: F02D 2041/2003 using means for creating a boost voltage, i.e. generation or use of a voltage higher than the battery voltage, e.g. to speed up injector opening
• CPC Class Codes: F02D 2041/2013 by using a boost voltage source
• CPC Class Codes: F02D 2041/389 for injecting directly into the cylinder
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: F02D 41/40 with means for controlling injection timing or duration
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A fuel injector control system for a cylinder injection type internal combustion engine capable of suppressing a concentrative heat generation at a voltage generating circuit, which system includes a sensor means (1) for detecting operation state of the internal combustion engine to thereby output engine operation state information (D), a control parameter arithmetic means (2) for determining arithmetically a fuel supply quantity and a fuel injection timing for the engine on the basis of the engine operation state information (D), a plurality of cylinder injection type fuel injectors (61 to 66) for injecting fuel directly and individually to cylinders (#1 to #6) of the engine, a driving circuit (5) for driving electrically the fuel injectors (61 to 66) in response to control signals (C1, . . . , C6) outputted from the control parameter arithmetic means (2), and a voltage generating circuit (4) for supplying fuel injection signals (J1, . . . , J6) to the fuel injectors (61, . . . , 66) through the medium of the driving circuit (5), wherein the voltage generating circuit (4) includes a high-voltage generating means (4H1, 4H2) for supplying overexcitation signals (E1, . . . , E6) in an initial phase of the fuel injection signal (J1, . . . , J6), and a low-voltage generating means (4L1, 4L2) for holding the fuel injection signal (J1, . . . , J6) to be constant at a predetermined current level. The high-voltage generating means (4H1, 4H2) and the low-voltage generating means (4L1, 4L2) are provided in parallel in a number corresponding to that of groups (#1, #3, #5; #2, #4, #6) of the cylinders (#1, . . . , #6) to be controlled groupwise.

Claims

1. A fuel injector control system for a cylinder injection type internal combustion engine, comprising:

sensor means for detecting operation state of said internal combustion engine to thereby output engine operation state information;

control parameter arithmetic means for determining arithmetically a fuel supply quantity and a fuel injection timing for said internal combustion engine on the basis of said engine operation state information;

a plurality of cylinder injection type fuel injectors for injecting fuel directly and individually to cylinders of said internal combustion engine;

a driving circuit for driving electrically said fuel injectors in response to control signals outputted from said control parameter arithmetic means; and

a voltage generating circuit for supplying fuel injection signals to said fuel injectors through the medium of said driving circuit,

wherein said voltage generating circuit includes;

high-voltage generating means for supplying overexcitation signals in an initial phase of said fuel injection signal; and

low-voltage generating means for holding said fuel injection signal to be constant at a predetermined current level, and

wherein said high-voltage generating means and said low-voltage generating means are provided in parallel in a number corresponding to the number of groups of said cylinders to be controlled groupwise.

2. A fuel injector control system according to claim 1,

wherein the groups of said cylinders energized groupwise by said high-voltage generating means and said low-voltage generating means are constituted by the cylinders for which the fuel injection sequence is distanced by two strokes.

3. A fuel injector control system according to claim 1, said driving circuit including:

a plurality of inhibiting means for inhibiting individually high-voltage outputs of said high-voltage generating means during output periods of said overexcitation signals, respectively,

wherein said inhibiting means inhibits generation of the high voltage by said high-voltage generating means in response to said overexcitation signals for said cylinder groups to be controlled.

4. A fuel injector control system for a cylinder injection type internal combustion engine, comprising:

sensor circuitry operable to detect an operation state of said internal combustion engine and output engine operation state information;

control parameter arithmetic circuitry operably connected to said sensor circuitry to receive said engine operation state information, said arithmetic circuitry operable to determine a fuel supply quantity and a fuel injection timing for said internal combustion engine on the basis of said engine operation state information;

a plurality of cylinder fuel injectors for injecting fuel directly and individually to cylinders of said internal combustion engine;

a driving circuit operable to drive electrically said fuel injectors in response to control signals outputted from said control parameter arithmetic circuitry; and

a voltage generating circuit operable to supply fuel injection signals to said fuel injectors through said driving circuit,

wherein said voltage generating circuit includes;

high-voltage generating circuitry operable to supply overexcitation signals in an initial phase of said fuel injection signal; and

low-voltage generating circuitry operable to hold said fuel injection signal to be constant at a predetermined current level, and

wherein said high-voltage circuitry and said low-voltage circuitry are provided in parallel.

5. A fuel injector control system according to claim 4, wherein said high-voltage generating circuitry and said low-voltage circuitry are provided in parallel in a number corresponding to the number of groups of said cylinders to be controlled groupwise.

6. A fuel injector control system according to claim 5, wherein the groups of said cylinders energized groupwise by said high-voltage generating circuitry and said low-voltage generating circuitry comprise the cylinders for which the fuel injection sequence is distanced by two strokes.

7. A fuel injector control system according to claim 5, said driving circuit including:

inhibiting circuitry operable to inhibit individually high-voltage outputs of said high-voltage generating circuitry during output periods of said overexcitation signals, respectively,

wherein said inhibiting circuitry inhibits generation of the high voltage by said high-voltage generating circuitry in response to said overexcitation signals for said cylinder groups to be controlled.

8. A fuel injector control system according to claim 4, wherein the control system is capable of individually controlling the amount of fuel sent to each fuel injector.