Method and apparatus for controlling internal combustion engines

• US 4,508,075 A
• Filed: 10/14/1981
• Issued: 04/02/1985
• Est. Priority Date: 10/17/1980
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Mizuno, Toshiaki, Takao, Mitsunori
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/311,395
• Time in Patent Office: 1,266 Days
• Field of Search: 123/440, 123/486, 123/480, 123/478, 123/419, 123/436, 123/339, 123/489
• US Class Current: 123/339.11
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 41/1498 measuring engine roughness

Abstract

In accordance with an amount of a change or a proportion of the change of at least one of operating parameters, such as a crankshaft rotational speed, an intake pipe pressure, etc., of an internal combustion engine equipped with an electronically controlled fuel injection system, or a rate of incremental change of the amount of the change or the proportion of the change and in dependence on whether air-fuel ratio feedback compensation by the use of an oxygen sensor is effected or not, at least one of control variables, such as a fuel injection quantity, ignition timing, etc., is corrected to ensure stable control of the rotational speed of the engine during its idling and low speed operations.

Claims

1. An apparatus for controlling an internal combustion engine of the type having an electronically controlled fuel injection system effecting air-fuel ratio feedback compensation by using an oxygen sensor for sensing an oxygen content of an exhaust gas from said engine, in which at least one of a plurality of control variables of said engine is corrected in accordance with at least one of a plurality of operating parameters of said engine to stabilize at rotational speed of said engine, said apparatus comprising:

a sensor for detecting said one operating parameter; and

computing means comprising input/output means for receiving an output signal of said sensor, an interruption command unit, memory means, a computing unit and output means of said computing means, whereby in accordance with the determination as to whether said air-fuel ratio feedback compensation by using the oxygen sensor is effected or not by said electronically controlled fuel injection system and in accordance with data related to an amount of change of said one operating parameter obtained at intervals of a predetermined period, correction values for said control variable are computed, said control variable is corrected in accordance with said correction values, and a signal indicative of said corrected control variable is output from said output means,

wherein said computing means has an interruption processing control program stored in said memory means thereby to perform said determination, computation, correction and outputting in response to an interruption command signal generated from said interruption command unit, and

wherein said memory means stores therein two different data maps to be used separately in dependence on whether said air-fuel ratio feedback compensation by using the oxygen sensor is effected or not, each of said data maps determining the relationship between the amount of change of said operating parameter and correction factors for computing correction values of said control variable, and wherein said interruption processing control program includes processing steps whereby correction factors for said control variable corresponding to the amount of change of said one operating parameter are read from a corresponding one of said data maps depending on whether said air-fuel ratio feedback compensation by using the oxygen sensor is effected or not.

3. A control apparatus according to claim 1, wherein said control variable correction factors in each of said data maps are determined to compensate for the amount of change of said one operating parameter, and wherein said correction factors for said control variable corresponding to the amount of change of said one operating parameter are made to take different values depending on whether said air-fuel ratio feedback compensation by using the oxygen sensor is being effected or not.

2. A method for controlling rotational speed of an internal combustion engine having an electronically controlled fuel injection system and an ignition system comprising the steps of:

sensing a pressure in an intake pipe of said engine, a rotational speed of said engine and an oxygen content in the exhaust of said engine;

determining an amount of fuel to be injected into said engine in accordance with said sensed pressure, rotational speed and oxygen content, said sensed oxygen content being used only when a feedback control responsive to said sensed oxygen content is desired;

monitoring whether said feedback control is effected or not;

detecting an amount of change in at least one of said sensed pressure and rotational speed between the precedingly sensed one and the currently sensed one;

determining a fuel correction value in dependence on said detected amount of change, said fuel correction value being varied in dependence on the result of said monitoring step;

correcting said determined amount of fuel to be injected by said determined fuel correction value;

injecting said corrected amount of fuel into said engine to be ignited by said ignition system;

repeating said sequence of steps;

determining an ignition timing in accordance with said sensed pressure and rotational speed;

determining an ignition correction value in dependence on said detected amount of change, said ignition correction value being varied in dependence on the result of said monitoring step;

correcting said determined ignition timing by said determined ignition correction value; and

igniting said injected fuel at said corrected ignition timing,

wherein said change detecting step detects said amount of change in both said sensed pressure and rotational speed.

4. A method for controlling an internal combustion engine of the type having an electronically controlled fuel injection system effecting air-fuel ratio feedback compensation by using an oxygen sensor for sensing an oxygen content of an exhaust gas from said engine, in which at least one of a plurality of control variables of said engine is corrected in accordance with at least one of a plurality of operating parameters of said engine to stabilize a rotational speed of said engine, said method comprising the steps of:

detecting an amount of change of said one operating parameter at intervals of a predetermined period;

determining for at least said one control variable and in accordance with data related to the amount of change of said one operating parameter, at intervals of said predetermined period, a first group of correction values if said air-fuel ratio feedback compensation is effected by use of said oxygen sensor and a second group of correction values if said compensation is not effected by use of said oxygen sensor;

correcting said control variable by using the determined correction values of one of said groups; and

controlling said engine by applying said corrected control variable thereto.

7. A control method according to claim 4, wherein said operating parameters include at least a rotational speed of said engine and a pressure in an intake pipe of said engine.

8. A control method according to claim 4 or 7, wherein said control variables include at least one of a fuel injection quantity and an ignition timing of said engine.

9. A control method according to claim 4, wherein the predetermined period is a predetermined time period.

10. A control method according to claim 4, wherein the predetermined period is a predetermined rotational angle of a crankshaft of said engine.

5. A method for controlling rotational speed of an internal combustion engine having an electronically controlled fuel injection system and an ignition system comprising the steps of:

sensing a pressure in an intake pipe of said engine, a rotational speed of said engine and an oxygen content in the exhaust of said engine;

determining an amount of fuel to be injected into said engine in accordance with said sensed pressure, rotational speed and oxygen content, said sensed oxygen content being used only when a feedback control responsive to said sensed oxygen content is desired;

monitoring whether said feedback control is effected or not;

detecting an amount of change in at least one of said sensed pressure and rotational speed between the precedingly sensed one and the currently sensed one;

determining, in dependence on said detected amount of change, a first group of fuel correction values if said monitoring indicates said feedback control is effected and a second group of fuel correction values if said feedback control is not effected;

correcting said determined amount of fuel to be injected by one of said groups of determined fuel correction values;

injecting said corrected amount of fuel into said engine to be ignited by said ignition system; and

repeating said sequence of steps.

11. A method according to claim 5 further comprising the steps of:

determining an ignition timing in accordance with said sensed pressure and rotational speed;

determining an ignition correction value in dependence on said detected amount of change, said ignition correction value being varied in dependence on the result of said monitoring step;

correcting said determined ignition timing by said determined ignition correction value; and

igniting said injected fuel at said corrected ignition timing.

6. An apparatus for controlling an internal combustion engine of the type having an electronically controlled fuel injection system effecting air-fuel ratio feedback compensation by using an oxygen sensor for sensing an oxygen content of an exhaust gas from said engine, in which at least one of a plurality of control variables of said engine is corrected in accordance with at least one of a plurality of operating parameters of said engine to stabilize at rotational speed of said engine, said apparatus comprising:

a sensor for detecting said one operating parameter; and

computing means comprising input means for receiving an output signal of said sensor and output means for computing for at least said one variable and in accordance with data related to an amount of change of said one operating parameter obtained at intervals of a predetermined period, a first group of correction values if said air-fuel ratio compensation is effected by said electronically controlled fuel injection system using said oxygen sensor and a second group of correction values if said compensation is not effected by using said oxygen sensor, for correcting said one control variable in accordance with the computed correction values of one of said groups, and for outputting via said output means a signal indicative of said corrected control variable.

12. A control apparatus according to claim 6, wherein said computing means has memory means and an interruption processing control program stored therein for performing said computating, correction and outputting in response to an interruption command signal.

13. A control apparatus according to claim 6, wherein the predetermined period is a predetermined time period.

14. A control apparatus according to claim 6, wherein the predetermined period is a predetermined rotational angle of a crankshaft of said engine.