Method for controlling the quantity of fuel and/or air to an internal combustion engine on a cylinder-by-cylinder basis

• US 20070175443A1
• Filed: 12/06/2006
• Published: 08/02/2007
• Est. Priority Date: 12/05/2005
• Status: Abandoned Application

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schueler, Matthias
• Application Number:
  US11/634,575
• Publication Number:
  US 20070175443A1
• Time in Patent Office: Days
• US Class Current: 123/402
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 41/0085 Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• CPC Class Codes: F02D 41/1498 measuring engine roughness

Abstract

A method for controlling the quantity of fuel and/or air to an internal combustion engine on a cylinder-by-cylinder basis is characterized in that a signal that is influenced by combustion or pertains to a quantity that influences the combustion and contains items of information from all cylinders, mutually offset in time, is analyzed by ascertaining vibration components in the frequency range caused by cylinder-specific differences and regulating these components separately for selected frequencies, and in that an amplitude regulator that determines the amplitude of a correction intervention measure and a phase regulator that determines the allocation of an intervention pattern with respect to the cylinders are provided for each frequency to be compensated.

Claims

1. A method for controlling a quantity of fuel and/or air to an internal combustion engine on a cylinder-by-cylinder basis, comprising:

analyzing a signal influenced by the combustion or pertaining to a quantity having influence on combustion and containing items of information from all cylinders, mutually offset in time, by ascertaining vibration components in the frequency range caused by cylinder-specific differences;

regulating the vibration components separately for selected frequencies; and

providing an amplitude regulator that determines the amplitude of a correction intervention and a phase regulator that determines the allocation of an intervention pattern with respect to the cylinders are provided for each frequency to be compensated.

2. The method as recited in claim 1, wherein the frequency of a camshaft signal and its multiples up to and including half the ignition frequency are analyzed.

3. The method as recited in claim 1, wherein an intervention into individual cylinder-specific actuating elements is performed, based on superimposing the control interventions ascertained for individual frequencies, in such a way that the control interventions at selected frequencies are calculated from the frequency-specific intervention amplitude ascertained by the amplitude regulator and the value derived for this cylinder from the frequency-specific intervention pattern.

4. The method as recited in claim 1, wherein the intervention pattern for a certain analysis frequency is a mean-free pattern and has a periodicity corresponding to this frequency.

5. The method as recited in claim 4, wherein the intervention pattern supplies a cylinder-specific value and is calculated on the basis of a sine as the basic function, a phase shift of the sine being implementable by an additive intervention by the phase regulator into the angle argument.

6. The method as recited in claim 1, wherein the phase regulator can induce a continuous shift in the intervention pattern between the cylinders through an additive intervention into the angle argument.

7. The method as recited in claim 1, wherein the phase regulator of a frequency keeps the intervention pattern constant when the ascertained cylinder-specific vibration at this frequency changes on account of the regulating intervention only in amplitude but not in phase.

8. The method as recited in claim 1, wherein with a change in phase, the phase regulator influences the angle argument of the periodic function in such a way that the intervention pattern into the cylinders is shifted so that this phase change is counteracted.

9. The method as recited in claim 1, wherein the amplitude regulator for a certain frequency compensates the vibration through intervention into the corresponding controlling amplitude.

10. The method as recited in claim 1, wherein when the shutdown threshold for the amplitude of a frequency is undershot, the regulating process by amplitude and phase regulators is stopped for this frequency and is not restarted until an activation threshold is exceeded.

11. The method as recited in claim 1, wherein the phase and amplitude regulators are active at the same time.

12. The method as recited in claim 1, wherein the phase and amplitude of the selected signal frequencies are ascertained by a Fourier transform or a fast Fourier transform.

13. The method as recited in claim 1, wherein the phase and the amplitude of the selected signal frequencies are ascertained by bandpass filtering.

14. The method as recited in claim 1, wherein the phase and/or amplitude of the individual frequencies are kept constant by a PI regulator.

15. The method as recited in claim 1, wherein the rotational speed signal is used as the input signal and the cylinder-specific injection quantity is used as the intervention quantity.

16. The method as recited in claim 1, wherein the lambda value, the pressure in the intake tract or the pressure in the exhaust system is used as the input signal, and the cylinder-specific injection quantity or cylinder-specific air controller is used as the intervention quantity.