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

• US 4,153,013 A
• Filed: 07/11/1977
• Issued: 05/08/1979
• 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:
  US05/814,611
• Time in Patent Office: 666 Days
• Field of Search: 123/32 EA, 123/119 A, 123/117 R, 73/517 A, 73/70.1, 73/117.3
• US Class Current: 123/435
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• CPC Class Codes: F02D 41/182 for the control of a fuel injection device
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The composition of the combustible mixture supplied to an internal combustion engine is controlled in dependence on the fluctuations in cylinder pressure which are monitored by sensing the fluctuations in the rotation of the engine crankshaft. These fluctuations are measured by comparison with a signal which simulates an engine running uniformly at the basic engine r.p.m. The signal which characterizes the r.p.m. fluctuations is compared with a nominal or command value and the resulting signal is used to control the mixture composition so as to maintain the fluctuations within predetermined limits.

Claims

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

(A) generating a first electrical signal representative of the angular position of a rotating member of the engine, said signal being generated in rpm synchronized time intervals;

(B) generating a second electrical signal by twice integrating the first electrical signal, said second electrical signal being representative of the angular position of an object rotating uniformly at the same rpm as said rotating member of the engine;

(C) measuring the relative phase angle between said first and said second electrical signals, said measurement of the relative phase angle corresponding to the fluctuations of the mean combustion chamber pressure; and

(D) adjusting the fuel-air ratio of the fuel-air mixture admitted to the internal combustion engine in dependence on said phase angle.

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

(A) generating a first electrical signal representative of the angular position of a rotating member of the engine, said signal being generated in rpm synchronized time intervals;

(B) generating a second electrical signal by twice integrating the first electrical signal, said second electrical signal being representative of the angular position of an object rotating uniformly at the same rpm as said rotating member of the engine;

(C) measuring the relative phase angle between said first and said second electrical signals, said measurement of the relative phase angle corresponding to the fluctuations of the mean combustion chamber pressure; and

(D) adjusting the amount of exhaust gas which is recycled to the intake side of the engine in dependence on said phase angle.

3. An apparatus for controlling the operation of an internal combustion engine comprising:

(A) first signal generator means comprising an indicator operatively associated with the engine crankshaft and a pulse generator assembly, for detecting the periodic passage of the indicator relative to the pulse generator assembly, for generating a corresponding first electrical signal indicative of the engine crankshaft rotation, and for transmitting said first signal to an input of a phase comparator;

(B) second signal generator means connected to one output of the phase comparator, for generating, from said first electrical signal, a uniform periodic second electrical signal corresponding to the rotational frequency of a uniformly rotating engine crankshaft and for transmitting said second signal to an input of the phase comparator, said second signal generator means including means for performing a two-step integration of said first signal to produce said second signal; and

(C) a phase comparator, for comparing the relative phase angle between said first and second electrical signals and for generating an output signal when said signals are asynchronous, said comparison corresponding to the fluctuations of the mean combustion chamber pressure;

whereby said output signal may be used to control the composition of the fuel-air combustion mixture.

4. An apparatus as defined in claim 3, wherein said first integrator is composed of passive elements and said second integrator includes an operational amplifier and a capacitor connected between its input and its output and wherein the output of said first integrator is connected to the input of said second integrator and the output of said second integrator is connected to the input of said voltage-controlled oscillator.

5. An apparatus as defined in claim 3, wherein the signal fed to said voltage-controlled oscillator is substantially equal to the sum of the output signals from said first and from said second integrators.

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

(D) a controlled current source which delivers a current which is proportional to the output signal of said second integrator.

7. An apparatus as defined in claim 6, further comprising:

(E) a semiconductor switch whose control electrode is connected to an output terminal of said phase comparator; and

(F) a capacitor, connected to said semiconductor switch;

whereby said semiconductor switch controls the charging rate of said capacitor.

8. An apparatus as defined in claim 7, wherein said capacitor is connected so as to be charged by said controlled current source.

9. An apparatus as defined in claim 7, further comprising:

(G) a comparator circuit with at least two inputs, one input being connected to said capacitor and the other input being provided with a reference voltage.

10. An apparatus as defined in claim 9, further comprising:

(H) a servo element controlled by the output of said comparator for changing the composition of the fuel-air mixture supplied to the engine.

11. An apparatus as defined in claim 10, wherein said servo element has integral control characteristics.

12. An apparatus as defined in claim 10, wherein the composition of the fuel-air mixture is changed by altering the amount of exhaust gas returned to the intake of the engine.

13. An apparatus for controlling the operation of an internal combustion engine comprising:

(A) first signal generator means, for detecting the motion of a rotating member of the engine and for generating a corresponding first electrical signal, said rotating member including an indicator operatively associated with the engine crankshaft;

(B) second signal generator means, for generating a uniform periodic second electrical signal corresponding to the rotational frequency of a uniformly rotating engine member; and

(C) a phase comparator, for comparing the relative phase angle between said first and second electrical signals and for generating an output signal;

whereby said output signal may be used to control the composition of the fuel-air combustion mixture, whereas said second signal generator means includes;

(i) first and second integrators, connected in series to an output connection of said phase comparator; and

(ii) a voltage-controlled oscillator connected in series with said first and second integrators, the output terminal of said voltage-controlled oscillator being connected to an input connection of said phase comparator.