Apparatus and method for injecting fuel into engine according to group injection system

• US 4,706,196 A
• Filed: 08/08/1985
• Issued: 11/10/1987
• Est. Priority Date: 08/10/1984
• Status: Expired due to Fees

• Current Assignee: Nippondenso Company Limited 1-1 Showa-Cho Kariya-Shi Aichi Japan
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Harada, Takashi, Isomura, Shigenori, Muramatsu, Toshihiko
• Primary Examiner(s): Lall, Parshotam S.
• Application Number:
  US06/763,795
• Time in Patent Office: 824 Days
• Field of Search: 364/431.05, 364/431.07, 364/551, 123/414, 123/480, 73/116, 73/117.3, 73/119 A, 324/167
• US Class Current: 701/103
• CPC Class Codes: F02D 41/345 Controlling injection timing F02D41/365 takes precedence
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In apparatus for injecting fuel into an internal combustion engine, a flip-flop used for frequency dividing an engine rotational angle signal is arranged to be reset when a basic injection pulse is not coincident with a cylinder-determining pulse signal. The basic injection pulse is produced by a Q/N charge-discharge circuit arranged to start charging a capacitor in response to a leading edge of an output pulse from the flip-flop and to start discharging the same in response to a trailing edge of the same where time constant on charging is constant and time constant on discharging is variable depending on the quantity Q of intake air of the engine. The basic injection pulse is used to produce final injection pulse with which fuel injection valves are operated where the width of the basic injection pulse determines the basic amount of fuel to be injected. After the flip-flop is reset, its output pulse is shifted by 180° CA, and thus the basic injection pulse TP occurs just before the final injection pulse thereby the latest engine operating conditions are reflected on the amount of fuel to be injected.

Claims

1. Apparatus for controlling fuel injection, for an internal combustion engine, comprising:

(a) a rotational angle sensor for generating a pulse signal synchronized with the rotation of said engine;

(b) a cylinder-determining sensor for producing a pulse signal indicative of a reference rotational angle of said engine;

(c) an airflow meter for producing an output signal indicative of intake airflow sucked into said engine;

(d) a flip-flop responsive to said pulse signal synchronized with engine rotation for frequency dividing the same;

(e) a charge-discharge circuit arranged to start charging in response to an output signal from said flip-flop with a first time constant and to start discharging in response to an invesion of said output signal from said flip-flop with a second time constant, one of said first and second time constants being variable in accordance with said output signal from said airflow meter, said charge-discharge circuit having means for producing a basic injection pulse whose width is defined by a period of time required for discharging;

(f) computing means responsive to said basic injection pulse, said pulse signal from said cylinder-determining sensor, and said pulse signal from said rotational angle sensor;

for generating plural groups of final injection pulse signals to be respectively fed to respective groups of fuel injectors of said engine such that final injection pulse signal to be fed to a particular group of fuel injectors are generated with a timing of said pulse from said cylinder-determining sensor;

for determining whether all said basic injection pulse, said pulse from rotational angle sensor and said pulse signal from said cylinder-determining sensor coincide with each other or not; and

for producing a control signal when the conincidence is not detected; and

(g) means for causing said flip-flop to produce said output signal which is shifted with respect to said output signal produced before receiving said control signal so that charging and discharging operation of said charge-discharge circuit is shifted accordingly.

2. Apparatus as claimed in claim 1, wherein said means for causing said flip-flop comprises means for resetting said flip-flop.

3. Apparatus as claimed in claim 1, wherein said means for causing said flip-flop is arranged to shift said basic injection pulse by 180°

CA.

4. Apparatus as claimed in claim 1, wherein said flip-flop comprises a D flip-flop with a reset terminal.

5. A method of controlling fuel injection, for an internal combustion engine, said method comprising the steps of:

(a) generating a pulse signal synchronized with the rotation of said engine;

(b) producing a pulse signal indicative of a reference rotational angle of said engine;

(c) producing an output signal indicative of intake airflow sucked into said engine;

(d) frequency dividing said pulse signal synchronized with engine rotation by way of a flip-flop;

(e) starting charging a charge-discharge circuit in response to an output signal from said flip-flop with a first time constant and starting discharging in response to an invesion of said output signal from said flip-flop with a second time constant, one of said first and second time constants being variable in accordance with said output signal indicative of intake airflow, said charge-discharge circuit producing a basic injection pulse whose width is defined by a period of time required for discharging;

(f) generating plural groups of final injection pulse signals to be respectively fed to respective groups of fuel injectors of said engine such that final injection pulse signal to be fed to a particular group of fuel injectors are generated with a timing of said pulse indicative of a reference rotational angle of said engine;

(g) determining whether all said basic injection pulse, said pulse synchronized with the rotation of said engine, and said pulse signal indicative of a reference rotational angle of said engine coincide with each other or not; and

(h) producing a control signal when the conincidence is not detected; and

(i) causing said flip-flop to produce said output signal which is shifted with respect to said output signal produced before receiving said control signal so that charging and discharging operation of said charge-discharge circuit is shifted accordingly.