Method and apparatus for controlling the operation of an internal combustion engine

• US 4,161,162 A
• Filed: 07/07/1977
• Issued: 07/17/1979
• Est. Priority Date: 04/09/1974
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Latsch, Reinhard, Bianchi, Valerio
• Primary Examiner(s): Cox, Ronald B.
• Application Number:
  US05/815,383
• Time in Patent Office: 740 Days
• Field of Search: 123/32 EA, 123/139 E, 332/9 T, 317/5, 73/117.3, 73/517 A, 73/70.1
• US Class Current: 123/435
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/149 Replacing of the control value by an other parameter
• CPC Class Codes: F02D 41/1498 measuring engine roughness

Abstract

An electronic control circuit for operating an internal combustion engine near its lean running limit includes means for measuring the scattering bandwidth of the cyclic fluctuations of the combustion chamber pressure. This measurement is made indirectly by measuring the angular speed a rotating engine member, e.g., the crankshaft, and by forming and storing an appropriate analog signal. Circuitry is provided which supplies a nominal value of the scattering bandwidth which is compared electrically with the measured actual value. An appropriately processed difference signal is fed to a fuel injection controller which changes the fuel-air mixture to the desired ratio.

Claims

1. An apparatus for controlling the operation of an internal combustion engine, which includes a crankshaft, comprising:

(A) sensor means associated with the crankshaft, for sensing crankshaft rotation during a predetermined measurement-time interval and forming an electrical signal related to the crankshaft rotation, said measurement-time interval corresponding to an angular region of the crankshaft rotation related to at least one stroke of a piston of the engine;

(B) actual value signal generator means including integration means, connected to said sensor means, for integrating sequential ones of the electrical signals generated by the sensor means generating during the predetermined measurement-time interval an electrical actual value signal related to the speed of rotation of the crankshaft, which signal is representative of the fluctuation in the average combustion chamber pressure in two sequential time intervals;

(C) nominal value signal generator means, for generating an electrical nominal value signal from engine parameters;

(D) first comparator means, for electrically comparing said actual value signal with said nominal value signal and for forming an electrical output signal; and

(E) servo means, connected to the output of said first comparator means, for adjusting the composition of the fuel-air mixture of said internal combustion engine in response to the electrical output signal.

11. An apparatus as defined in claim 1, further comprising:

(I) controller means, with integral control behavior, connected between said first comparator means and said servo means.

13. An apparatus as defined in claim 1, further comprising:

(P) switching means, for interrupting the connection between said first comparator means and said servo means; and

(Q) sensor means for sensing a particular engine condition and for actuating said switching means.

14. An apparatus as defined in claim 13, further comprising:

(R) control means, connectable to said servo means by said switching means when actuated, for controlling the operation of the internal combustion engine in a domain substantially different from that in which it operates when said switching means is not actuated by said sensor means, especially for operation in a domain in which the fuel-air ratio is that of a stoichiometric mixture.

16. An apparatus as defined in claim 1, wherein said sensor means includes a disc with markings, mounted on said rotating drive means for defining the angular orientation thereof.

17. An apparatus as defined in claim 1, wherein said nominal value signal generator includes means for forming a signal which is proportional to the inverse third power of the rpm of the engine and constitutes a nominal value of the rotation time of said rotating drive means.

23. An apparatus as defined in claim 1, wherein said servo means has an integral operational characteristic.

24. An apparatus as defined in claim 23, further comprising:

(Z) connecting means for establishing communication between the intake and exhaust manifolds of said internal combustion engine; and

(AA) valve means, located within said connecting means, capable of defining the flow cross-section thereof and controlled by said servo means.

2. An apparatus for controlling the operation of an internal combustion engine, which includes rotating drive means comprising:

(A) sensor means, associated with said rotating drive means, for forming an electrical signal related to the rotation of said rotating drive means, which rotation is related to the combustion chamber mean pressure;

(B) actual value signal generator means, connected to said sensor means, for generating an electrical actual value signal related to the speed of rotation of said rotating drive means;

(C) nominal value signal generator means for generating an electrical nominal value signal from engine parameters;

(D) first comparator means for electrically comparing said actual value signal with said nominal value signal and for forming an electrical output signal;

(E) servo means, connected to the output of said first comparator means, for adjusting the composition of the fuel-air mixture of said internal combustion engine;

(F) a first shift register, for storing sequential ones of said electrical actual value signals;

(G) a selector circuit, for selecting the smallest and the largest of said signals stored in said first shift register; and

(H) an arithmetic circuit, connected to the output of said selector circuit, for forming a signal representative of the difference between said largest and said smallest of the signals stored in said first shift register, wherein said actual value signal generator means includes at least two data storage locations and said electrical actual value signal is representative of the fluctuations in the average combustion chamber pressure in two sequential time intervals.

3. An apparatus for controlling the operation of an internal combustion engine, which includes rotating drive means comprising:

(A) sensor means, associated with said rotating drive means, for forming an electrical signal related to the rotation of said rotating drive means, which rotation is related to the combustion chamber mean pressure;

(B) actual value signal generator means, connected to said sensor means, for generating an electrical actual value signal related to the speed of rotation of said rotating drive means;

(C) nominal value signal generator means for generating an electrical nominal value signal from engine parameters;

(D) first comparator means, for electrically comparing said actual value signal with said nominal value signal and for forming an electrical output signal;

(E) servo means, connected to the output of said first comparator means, for adjusting the composition of the fuel-air mixture of said internal combustion engine;

(F) electrical rectifying means, connected to the output of said actual value signal generator, for rectifying the signals thereof;

(G) second comparator means, whose first input receives the output of said rectifying means and whose second input receives signals from said nominal value signal generator means;

(H) a second shift register which receives signals from said second comparator means;

(I) circuit means for forming an electrical average of signals received from said second shift register; and

(J) diode means, connected between said circuit means and said servo means.

12. An apparatus as defined in claim 3, further comprising:

(O) electrical correcting means, connected between said second comparator means and said nominal value signal generator means, for correcting the electrical signals from said nominal value signal generator means.

4. An apparatus for controlling the operation of an internal combustion engine, which includes rotating drive means comprising:

(A) sensor means, associated with said rotating drive means, for forming an electrical signal related to the rotation of said rotating drive means, which rotation is related to the combustion chamber mean pressure;

(B) actual value signal generator means, connected to said sensor means, for generating an electrical actual value signal related to the speed of rotation of said rotating device means;

(C) nominal value signal generator means for generating an electrical nominal value signal from engine parameters;

(D) first comparator means, for electrically comparing said actual value signal with said nominal value signal and for forming an electrical output signal;

(E) servo means, connected to the output of said first comparator means, for adjusting the composition of the fuel-air mixture of said internal combustion engine;

(F) pulse train generator means to receive signals from said sensor means and adapted to deliver signals to said nominal value signal generator for forming rmp-related nominal value signals and also connected to deliver signals to said actual value generator means;

(G) first AC amplifier means, for amplifying signals from said at least two data storage locations;

(H) rectifying means between said first AC amplifier means and said first comparator means, said first comparator means also being arranged to receive signals from said nominal value signal generator means; and

(I) a bistable multivibrator whose first input is arranged to receive signals from said first comparator means, the second input of which is connected to its own output, with the clock input arranged to receive signals from said pulse train generator means and the output of which is arranged to operate said servo means, wherein said actual value signal generator means includes at least two data storage locations.

15. An apparatus as defined in claim 4, further comprising:

(W) controller means with integral control behavior, disposed between said output of said bistable multivibrator and said servo means.

5. An apparatus for controlling the operation of an internal combustion engine, which includes rotating drive means comprising:

(A) sensor means, associated with said rotating drive means, for forming an electrical signal related to the rotation of said rotating drive means, which rotation is related to the combustion chamber mean pressure;

(B) actual value signal generator means, connected to said sensor means, for generating an electrical actual value signal related to the speed of rotation of said rotating drive means;

(C) nominal value signal generator means for generating an electrical nominal value signal from engine parameters;

(D) first comparator means, for electrically comparing said actual value signal with said nominal value signal and for forming an electrical output signal; and

(E) servo means, connected to the output of said first comparator means, for adjusting the composition of the fuel-air mixture of said internal combustion engine, wherein said nominal value signal generator includes three electrical integrating circuits, disposed in series, for forming a signal which is proportional to the inverse third power of the rpm of the engine and constitutes a nominal value of the rotation time of said rotating drive means.

18. An apparatus as defined in claim 5, wherein each of said three electrical integrating circuits includes an integrating capacitor and, parallel thereto, a switch which can short-circuit said integrating capacitor when actuated by said pulse train generator means.

19. An apparatus as defined in claim 18, further comprising:

(X) a first interrupter switch, actuatable by said pulse train generator means and connected between the output of said nominal value signal generator means and said first comparator means.

20. An apparatus as defined in claim 19, further comprising:

(Y) circuit means, including an integrator, a second interruptor switch and a second AC amplifier means all in series, connected between said first AC amplifier means and said rectifying means.

21. An apparatus as defined in claim 20, wherein said circuit means further includes an integrating capacitor, connected to said integrator and an electronic switch in parallel with said integrating capacitor and actuatable by said pulse train generator means, for resetting said integrator to zero.

22. An apparatus as defined in claim 21, wherein said circuit means further includes a monostable multivibrator, connected to said pulse train generator means, for actuating said second interruptor switch.

6. An apparatus for controlling the operation of an internal combustion engine, which includes rotating drive means comprising:

(A) sensor means, associated with said rotating drive means, for forming an electrical signal related to the rotation of said rotating drive means, which rotation is related to the combustion chamber means pressure;

(B) actual value signal generator means, connected to said sensor means, for generating an electrical actual value signal related to the speed of rotation of said rotating drive means, said actual value signal generator means includes at least two data storage locations;

(C) nominal value signal generator means for generating an electrical nominal value signal from engine parameters;

(D) first comparator means, for electrically comparing said actual value signal with said nominal value signal and for forming an electrical output signal;

(E) servo means, connected to the output of said first comparator means, for adjusting the composition of the fuel-air mixture of said internal combustion engine;

(F) pulse train generator means to receive signals from said sensor means and adapted to deliver signals to said nominal value signal generator for forming rpm-related nominal value signals and also connected to deliver signals to said actual value generator means;

(G) first AC amplifier means, for amplifying signals from said at least two data storage locations; and

(H) rectifying means between said first AC amplifier means and said first comparator means, said first comparator means also being arranged to receive signals from said nominal value signal generator means.

7. A method for controlling the operation of an internal combustion engine, comprising the steps of:

(A) determining a measurement-time interval, the duration of which corresponds to an angular region of the crankshaft rotation related to at least one stroke of a piston of the engine;

(B) generating a measurement value from an engine operating parameter during the measurement-time interval, said generated measurement value varying during the measurement-time interval as a measure of the fluctuations of the angular speed of the crankshaft over said angular region, and corresponding to the average combustion chamber pressure;

(C) integrating the measurement value generated;

(D) comparing an integrated measurement value generated during a subsequent measurement-time interval and generating a differential value as an actual value of the combustion chamber'"'"'s average pressure;

(E) generating a nominal value of the combustion chamber average pressure; and

(F) adjusting the fuel-air ratio of the fuel-air mixture admitted to the internal combustion engine in accordance with the difference between the nominal and actual values.

8. A method for controlling the operation of an internal combustion engine, comprising the steps of:

(A) determining a measurement-time interval, the duration of which corresponds to an angular region of the crankshaft rotation related to at least one stroke of a piston of the engine;

(B) generating a measurement value from an engine operating parameter during the measurement-time interval, said generated measurement value varying during the measurement-time interval as a measure of the fluctuations in the time taken by the crankshaft to rotate through said angular region, and corresponding to the average combustion chamber pressure;

(C) integrating the measurement value generated;

(D) comparing an integrated measurement value generated during a subsequent measurement-time interval and generating a differential value as an actual value of the combustion chamber'"'"'s average pressure;

(E) generating a nominal value of the combustion chamber average pressure; and

(F) adjusting the fuel-air ratio of the fuel-air mixture admitted to the internal combustion engine in accordance with the difference between the nominal and actual values.

9. A method for controlling the operation of an internal combustion engine, comprising the steps of:

(A) determining a measurement-time interval, the duration of which corresponds to an angular region of the crankshaft rotation related to at least one stroke of a piston of the engine;

(B) generating a measurement value from an engine operating parameter during the measurement-time interval, said generated measurement value varying during the measurement-time interval as a measure of the fluctuations of the angular speed of the crankshaft over said angular region, and corresponding to the average combustion chamber pressure;

(C) integrating the measurement value generated;

(D) comparing an integrated measurement value generated during a subsequent measurement-time interval and generating a differential value as an actual value of the combustion chamber'"'"'s average pressure;

(E) generating a nominal value of the combustion chamber average pressure; and

(F) adjusting the amount of exhaust gas which is recycled to the intake side of the engine in accordance with the difference between the nominal and actual values.

10. A method for controlling the operation of an internal combustion engine, comprising the steps of:

(A) determining a measurement-time interval, the duration of which corresponds to an angular region of the crankshaft rotation related to at least one stroke of a piston of the engine;

(B) generating a measurement value from an engine operating parameter during the measurement-time interval, said generated measurement value varying during the measurement-time interval as a measure of the fluctuations in the time taken by the crankshaft to rotate through said angular region, and corresponding to the average combustion chamber pressure;

(C) integrating the measurement value generated;

(D) comparing an integrated measurement value generated during a subsequent measurement-time interval and generating a differential value as an actual value of the combustion chamber'"'"'s average pressure;

(E) generating a nominal value of the combustion chamber average pressure; and

(F) adjusting the amount of exhaust gas which is recycled to the intake side of the engine in accordance with the difference between the nominal and actual values.