LEAN LIMIT INTERNAL COMBUSTION ENGINE ROUGHNESS CONTROL SYSTEM

• US 3,789,816 A
• Filed: 03/29/1973
• Issued: 02/05/1974
• Est. Priority Date: 03/29/1973
• Status: Expired due to Term

• Current Assignee: Siemens-Bendix Automotive Electronics LP
• Original Assignee: Chun Keung Leung, Lael B. Taplin, William R. Seitz
• Inventors: Seitz, William R., Taplin, Lael B., Leung, Chun Keung
• Primary Examiner(s): Burns, Wendell E.
• Assistant Examiner(s): Argenbright, Tony
• Application Number:
  US05/346,240
• Time in Patent Office: 313 Days
• Field of Search: 123/119R,139AW,198R,102,106,32AE,32EA 60/39.09
• US Class Current: 123/436
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• CPC Class Codes: G01P 15/165 for measuring angular accelerations

Abstract

A closed loop fuel control mechanism for controlling the air fuel mixture delivered to an internal combustion engine so as to regulate the roughness of the engine at a predetermined level. The control system receives as input signal a signal indicative of the engine roughness and processes this signal to generate an output control signal for controlling the fuel delivery mechanism of the internal combustion engine to operate that engine at the leanest possible air/fuel mixture ratio compatible with a predetermined level of engine roughness.

Claims

1. An engine control system for controlling an engine parameter of an internal combustion engine having a variable speed member the speed of which varies with the speed of the engine:

a. speed sensing means operatively associated with said variable speed member for providing a speed signal varying with the speed thereof;

b. speed signal differentiating means operatively connected in electrical circuit with said speed sensing means for providing a speed rate of change signal varying with a derivative of said speed signal;

c. rectifier means operatively connected in electrical circuit with said speed signal differentiating means for rectifying said speed rate of change signal and providing a rectified roughness output signal;

d. comparator means connected in electrical circuit with said rectifier means operative to provide a comparison signal having first and second magnitudes when said rectified roughness output signal is respectively above and below a predetermined magnitude;

e. integrator means operatively connected with said comparator means operative to generate a control signal having a magnitude changing at a first predetermined rate when the magnitude of said comparison signal is one of said first and second magnitudes and at a second predetermined rate when the magnitude of said comparison signal is the other of said first and second magnitudes; and

f. control means operatively connected with said integrator means and said engine responsive to control said engine parameter in accordance with said control signal.

2. The control system of claim 1, wherein said rectifier means comprises a full wave rectifier and wherein said first and second predetermined rates cause the magnitude of said control signal to respectively increase and decrease.

3. An engine control system for controlling an engine parameter of an internal combustion engine having a variable speed member the speed of which varies with the speed of the engine;

a. speed sensing means operatively associated with said variable speed member for providing a speed signal varying with the speed thereof;

b. speed signal differentiating means operatively connected in electrical circuit with said speed sensing means for providing a speed change signal varying with a derivative of said speed signal;

c. comparator means connected in electrical circuit with said speed signal differentiating means operative to provide a comparison signal having first and second magnitudes when the magnitude of said speed change signal is respectively above and below a predetermined magnitude;

d. integrator means operatively connected with said comparator means operative to generate a control signal increasing in magnitude when the magnitude of said comparison signal is one of said first and second magnitudes and decreasing the magnitude when the magnitude of said comparison signal is the other of said first and second magnitudes; and

e. control means operatively connected with said integrator means and said engine responsive to control said engine parameter in accordance with said control signal.

4. An engine control system for controlling an engine parameter of an internal combustion engine having a variable speed member the speed of which varies with the speed of the engine:

a. speed sensing means operatively associated with said variable speed member for providing a speed signal varying with the speed thereof;

b. speed signal differentiating means operatively connected in electrical circuit with said speed sensing means for providing a speed rate of change signal varying with a derivative of said speed signal;

c. rectifier means operatively connected in electrical circuit with said speed signal differentiating means for rectifying said speed rate of change signal and providing a roughness signal;

d. integrator means operatively connected with said rectifier means for generating a control signal varying with an integral of said roughness signal; and

e. control means operatively connected with said integrator means and said engine responsive to control said engine parameter in accordance with said control signal.

5. An air/fuel ratio control system for an internal combustion engine having controllable fuel delivery means and a rotatable member rotatable at speeds varying with the speed of the engine, said air/fuel ratio control system comprising:

a. speed sensor means responsively connected to The engine to provide a speed signal varying with the speed of the rotatable member;

b. differentiator means operatively connected to said speed sensor means for differentiating said speed signal and providing a roughness signal varying with a derivative of said speed signal;

c. integrator means operatively connected to said differentiator means for integrating said roughness signal to provide a predetermined correction signal; and

d. control means operatively connected to said integrator means and to said fuel delivery means for varying said air/fuel ratio by controlling said fuel delivery means in accordance with said predetermined correction signal.

6. An air/fuel ratio control system for controlling the mixture of air and fuel delivered to an internal combustion engine, the engine having air induction means for admitting an operator controllable air flow, fuel delivery means for delivering a controllable fuel flow to the air induction means in a controllable proportion to the air flow, and a rotatable member the momentary speed changes of which vary with the momentary speed changes of the engine to indicate the roughness of engine operation, said air/fuel control system comprising:

a. engine roughness sensing means responsively connected to the engine to sense momentary speed changes of the rotatable member and operative to provide a roughness signal having a magnitude varying with the sensed momentary speed changes; and

b. fuel delivery control means operatively connecting the fuel delivery means and the said engine roughness sensing means for controlling the fuel delivery means so as to vary the fuel flow in a preselected relationship to the air flow so as to maintain the magnitude of said roughness signal at a predetermined magnitude.

7. An air/fuel ratio limit control system for limiting the leanness of an air/fuel mixture delivered to an internal combustion engine, the engine having air induction means for admitting an operator controllable air flow, fuel delivery means for delivering a controllable fuel flow to the air induction means, and a rotatable member the speed of which varies with the speed of the engine and the speed change of which varies with the roughness of the engine and also with the magnitude of the air/fuel mixture delivered thereto, said air/fuel ratio limit control system comprising:

a. engine roughness sensing means responsive to the speed changes of the rotatable member to provide a roughness signal varying with the roughness of the engine; and

b. fuel delivery control means operative to normally control the fuel delivery means so as to deliver the fuel flow in a known relation to the air flow when the roughness signal is less than a predetermined magnitude and to otherwise cooperate with the roughness sensing means to cause the fuel delivery means to increase the fuel flow in relation to the air flow when said roughness signal exceeds said predetermined magnitude, whereby the leanness of the air/fuel mixture delivered to the engine is controlled to maintain said roughness signal below said predetermined magnitude.

8. An air/fuel ratio control system for controlling an engine performance related parameter of an internal combustion engine, the engine performance related parameter exceeding a predetermined magnitude as the magnitude of the air/fuel ratio exceeds a predetermined ratio, the engine having air induction means for admitting an operator control-lable air flow, controllable fuel metering means for providing a fuel flow in a controllable ratio to the air flow, and a variable speed member the instantaneous speed changes of which vary with the magnitude of the engine performance related parameter, said air/fuel ratio control system comprising:

a. speed change sensing means operatively coupled to said engine for providing a speed change signal varying in magnitude with the magnitude of said instantaneous speed changes of said variable speed member;

b. control signal generation means for Generating a speed change related control signal the magnitude of which increases as the magnitude of said speed change signal exceeds a predetermined magnitude; and

c. fuel metering control means operatively connected to said fuel metering means and said control signal generation means responsive to said speed change related control signal to normally increase the air/fuel ratio towards said predetermined ratio when the magnitude of said engine performance related parameter is less than said predetermined magnitude and to otherwise reduce the air/fuel ratio when the magnitude of said engine performance related parameter exceeds said magnitude, whereby the magnitudes of said air/fuel ratio and said engine performance related parameter are continually varied at magnitudes less than said predetermined ratio and predetermined magnitude.

9. An air/fuel ratio control system for an internal combustion engine having a rotatable member rotatable at speeds varying with the speed of the engine, air induction means for admitting an operator controllable air flow, controllable fuel metering means for varying the fuel flow in a controllable proportion to the air flow in accordance with a speed signal and with a speed change related signal, and a rotatable member rotatable at speeds varying with the speed of the engine, said air/fuel ratio control system comprising:

a. speed sensor means operatively connected to said control-lable fuel delivery means and to said rotatable member for generating said speed signal varying with the speed of the rotatable member;

b. differentiator means operatively connected to said speed sensor means for differentiating said speed signal and providing a roughnes signal varying with a derivative of said speed signal; and

c. signal generating means operatively connected with said differentiator means and said controllable fuel delivery means for generating said speed change related signal in accordance with a magnitude of said roughness signal, said speed change related control signal operative to cause said controllable fuel delivery means to increase the air/fuel ratio when said roughness signal is less than a predetermined roughness magnitude and to cause said controllable fuel delivery means to decrease the air/fuel ratio when said roughness signal is greater than said predetermined roughness magnitude.

10. An air/fuel ratio control system for an internal combustion engine having controllable fuel delivery means for varying the air/fuel ratio in accordance with a speed signal and the speed change related signal, a rotatable member rotatable at speeds varying with the speed of the engine, and speed sensor means responsively associated with said rotatable member for generating said speed signal for said controllable fuel delivery means, said speed signal having low frequency components indicative of low frequency driver commanded performance changes and higher frequency components varying with the magnitude of an engine performance related parameter, said air/fuel ratio control system comprising:

a. differentiator means operatively connected to said speed sensor means for differentiating said speed signal and providing a roughness signal varying with a derivative of at least said higher frequency components of said speed signal;

b. control means operatively connected to said differentiator means for generating said speed change related control signal in accordance with the magnitude of said roughness signal, said speed change related control signal causing said controllable fuel delivery means to increase said air/fuel ratio when said roughness signal is below a predetermined roughness magnitude and to decrease said air/fuel ratio when the magnitude of said roughness signal is above said predetermined roughness magnitude.

11. In the apparatus of claim 10, said derivative of said speed signal being the second derivative thereof whereby the magnitude of the resulting roughness signal varies with the magnitude of just said Higher frequency components of the speed signal so that the speed change related signal does not cause the fuel delivery means to decrease the air/fuel ratio in the presence of said low frequency driver commanded performance changes.

12. In the apparatus of claim 10, said control means including frequency sensitive control override means responsive to said low frequency components to prevent said speed change related signals from causing said fuel delivery means to decrease the air/fuel ratio in the presence of said low frequency driver commanded performance changes.

13. An air/fuel ratio control system for an internal combustion engine having controllable fuel delivery means and a rotatable member rotatable at speeds varying with the speed of the engine, said air/fuel ratio control system comprising:

a. speed sensor means responsively connected to the engine to provide the speed signal varying with the speed of the rotatable member, said speed signal having low and high frequency components;

b. differentiator means operatively connected to said speed sensor means for differentiating said speed signal and providing a roughness signal varying with a derivative of said high frequency component of said speed signal;

c. first control means operatively connecting said differentiator means and said controllable fuel delivery means causing said fuel delivery means to increase the air/fuel ratio when said roughness signal is less than a predetermined roughness magnitude and to decrease said air/fuel ratio when the magnitude of said roughness signal is greater than said predetermined roughness magnitude; and

d. second control means operatively connected between said first control means and said differentiator means for modifying said speed change related signal when the magnitude of said low frequency components exceeds a predetermined low frequency magnitude.

14. A roughness control system for controlling the roughness of an internal combustion engine, the engine having an operator controllable air fuel delivery means for delivering a controllable air fuel mixture and a rotatable member the momentary speed changes of which vary with the momentary speed changes of the engine to indicate the roughness of engine operation, said roughness control system comprising:

a. engine roughness sensing means responsively connected to the engine for sensing momentary speed changes of the rotatable member and providing a roughness signal having a magnitude varying with the sensed momentary speed changes; and

b. control means operatively connecting the air fuel delivery means and the said engine roughness sensing means for controlling the air fuel delivery means so as to regulate the magnitude of said roughness signal at a predetermined magnitude.

15. An air/fuel ratio control system for controlling the mixture of air and fuel delivered to an internal combustion engine, the engine having an operator controllable air fuel delivery means for delivering a variable ratio air fuel mixture and a rotatable member and momentary speed changes of which vary with the momentary speed changes of the engine to indicate the roughness of engine operation, said air/fuel control system comprising:

a. engine roughness sensing means responsively connected to the engine for sensing momentary speed changes of the rotatable member and providing a roughness signal having a magnitude varying with the sensed momentary speed changes; and

b. control means operatively connecting the air fuel delivery means and the said engine roughness sensing means for controlling the fuel delivery means so as to normally bias the air fuel ratio in a lean direction until the magnitude of said roughness signal exceeds a predetermined magnitude and to thereafter decrease the air fuel ratio in a rich direction, whereby the air fuel delivery means regulates the magnitude of said roughness signal at said predetermined magnitude.