Method for detecting the beginning of combustion in an internal combustion engine

• US 7,516,732 B2
• Filed: 01/20/2005
• Issued: 04/14/2009
• Est. Priority Date: 02/04/2004
• Status: Expired due to Fees

• Current Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Original Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Inventors: Meyer, Ernst, Tuna, Mehmet, Hagel, Reinhold
• Primary Examiner(s): SOLIS, ERICK R
• Application Number:
  US10/587,929
• Publication Number:
  US 20080127945A1
• Time in Patent Office: 1,545 Days
• Field of Search: 123/336, 123/406.58, 123/406.59, 123/406.65, 123/436
• US Class Current: 123/406.58
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 2200/1012 Engine speed gradient
• CPC Class Codes: F02D 35/028 by determining the combustion timing or phasing
• CPC Class Codes: F02D 41/008 Controlling each cylinder individually
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02D 41/1408 Dithering techniques

Abstract

A method detects the beginning of combustion in an internal combustion engine (1) having several cylinders (2, 3, 4, 5), form a rotation speed signal determined for a shaft (6) of the engine (1). A segment signal (SS), whose signal length corresponds to an integral multiple of one or more full rotation of the shaft (6), is extracted from the rotation speed signal. A cylinder signal (ZS1, ZS2, ZS3, ZS4), which reproduces the operational state in a cylinder (2, 3, 4, 5), is generated from the segment signal (SS). The cylinder signal is transformed into a cylinder frequency signal (FS1, FS2, FS3, FS4) in an angular frequency range. Signal information indicating the beginning of combustion in the associated cylinder is extracted from the cylinder frequency signal at least one predefined angular frequency.

Claims

1. A method for detecting the beginning of combustion in an internal combustion engine (1) having several cylinders (2, 3, 4, 5), from a rotation speed signal determined for a shaft (6) of the internal combustion engine (1), in which

at least one segment signal (SS), whose signal length corresponds to an integral multiple of one or more full rotations of the shaft (6), is extracted from the rotation speed signal, so that each cylinder (2, 3, 4, 5) ignites one time in the rotation angle range represented by the signal length,

a cylinder signal (ZS1, ZS2, ZS3, ZS4), which substantially reproduces the operational state in one of the cylinders (2, 3, 4, 5), is generated from the segment signal (SS),

the cylinder signal (ZS1, ZS2, ZS3, ZS4) is transformed into a cylinder frequency signal (FS 1, FS2, FS3, FS4) in an angle frequency range,

a signal information indicating the beginning of combustion in the associated cylinder (2, 3, 4, 5) is extracted from the cylinder frequency signal (FS 1, FS2, FS3, FS4) at least one predefined angle frequency with regard to amplitude and phase values associated with the predefined angle frequency, and

the beginning of combustion is detected from the signal information.

2. A method according to claim 1, characterized in that the cylinder signal (ZS1, ZS2, ZS3, ZS4) is generated by means of extraction of a partial signal from the segment signal (SS), the partial signal detecting the rotation angle range, within which the concerned cylinder (2, 3, 4, 5) ignites.

3. A method according to claim 1, characterized in that the operational state in the cylinder (2), for which the beginning of combustion is to be detected, is adjusted, and in that the segment signal (SS) resulting from adjustment is used as a whole as the cylinder signal (ZS1) which is significant for this cylinder (2).

4. A method according to claim 1, characterized in that the cylinder frequency signal (FS1, FS2, FS3, FS4) is generated by means of a discrete Hartley-Transformation (DHT) or a discrete Fourier-Transformation (DFT) or by means of digital filtering.

5. A method according to claim 1, characterized in that at least two successive segment signals (SS) are determined arithmetically.

6. A method according to claim 1, characterized in that for generating the rotation speed signal a transmitter wheel (7) is used and that the inaccuracies in the segment signal (SS) resulting from transmitter wheel errors are at least largely eliminated.

7. A method according to claim 1, characterized in that by means of a digital signal processing an improved segment signal (SS*), in particular with a higher scanning rate, is generated.

8. A method according to claim 7, characterized in that the segment signal (SS) is subject to an interpolation method, in particular to a Lagrange- or a sinc-interpolation.

9. A method according to claim 7, characterized in that the segment signal (SS) is subject to a frequency transformation, in particular to a discrete Hartley-Transformation or a discrete Fourier-Transformation.

10. A method according to claim 1, characterized in that the signal information indicating the beginning of combustion is used for regulating the beginning of combustion.