Method and device for analyzing a sensor element

• US 7,389,680 B2
• Filed: 09/21/2005
• Issued: 06/24/2008
• Est. Priority Date: 10/26/2004
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Kassner, Uwe
• Primary Examiner(s): McCall; Eric S.
• Assistant Examiner(s): JENKINS, JERMAINE L
• Application Number:
  US11/232,784
• Publication Number:
  US 20060086180A1
• Time in Patent Office: 1,007 Days
• Field of Search: 731/15
• US Class Current: 73/114.16
• CPC Class Codes: F02D 2041/281 between sensors and control unit
• CPC Class Codes: F02D 2041/285 the sensor having a signal processing unit external to the engine control unit
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 35/025 by determining temperatures inside the cylinder, e.g. combustion temperatures
• CPC Class Codes: F02D 41/28 Interface circuits
• CPC Class Codes: G01L 23/10 by pressure-sensitive members of the piezoelectric type
• CPC Class Codes: G01L 23/22 for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines
• CPC Class Codes: G01L 9/085 with temperature compensating means non electric temperature compensating means G01L19/04

Abstract

A method and a device for analyzing a sensor element are described, which allow a temperature dependence of the sensor element to be considered without an additional temperature sensor in particular. The sensor element outputs a signal as a function of a measured variable. The signal of the sensor element is analyzed in a first analysis operating mode to detect the measured variable. The signal of the sensor element is analyzed in a second analysis operating mode to detect a characteristic variable of the sensor element which is different from the measured variable.

Claims

1. A method for analyzing a sensor element which outputs a signal as a function of a measured variable, comprising:

analyzing the signal of the sensor element in a first analysis operating mode to detect the measured variable; and

analyzing the signal of the sensor element in a second analysis operating mode to detect a characteristic variable of the sensor element which is different from the measured variable, wherein the sensor element is a combustion chamber pressure sensor for detecting a combustion chamber pressure of an internal combustion engine.

3. The method as recited in claim 1, wherein the second analysis operating mode is set for a cylinder of the internal combustion engine during at least one exhaust stroke of the cylinder.

2. A method for analyzing a sensor element which outputs a signal as a function of a measured variable, comprising:

analyzing the signal of the sensor element in a first analysis operating mode to detect the measured variable; and

analyzing the signal of the sensor element in a second analysis operating mode to detect a characteristic variable of the sensor element which is different from the measured variable, wherein a changeover between the first analysis operating mode and the second analysis operating mode is performed as a function of at least one controlled variable,

wherein a crankshaft angle of an internal combustion engine is the controlled variable.

4. A method for analyzing a sensor element which outputs a signal as a function of a measured variable, comprising:

analyzing the signal of the sensor element in a first analysis operating mode to detect the measured variable; and

analyzing the signal of the sensor element in a second analysis operating mode to detect a characteristic variable of the sensor element which is different from the measured variable, wherein a frequency of setting the second analysis operating mode is selected as a function of a rate of change of the characteristic variable.

5. A method for analyzing a sensor element which outputs a signal as a function of a measured variable, comprising:

analyzing the signal of the sensor element in a first analysis operating mode to detect the measured variable; and

analyzing the signal of the sensor element in a second analysis operating mode to detect a characteristic variable of the sensor element which is different from the measured variable, wherein one of a temperature or a capacitance is analyzed as the characteristic variable of the sensor element.

6. The method as recited in claim 5, further comprising:

incorporating the sensor element into an oscillator circuit to detect the temperature or capacitance, the oscillator circuit generating a frequency that is a function of only the capacitance of the sensor element.

7. The method as recited in claim 6, wherein the oscillator circuit is an astable multivibrator.

8. A method for analyzing a sensor element which outputs a signal as a function of a measured variable, comprising:

analyzing the signal of the sensor element in a first analysis operating mode to detect the measured variable;

analyzing the signal of the sensor element in a second analysis operating mode to detect a characteristic variable of the sensor element which is different from the measured variable; and

incorporating the sensor element into an impedance transformer circuit or into a charge amplifier circuit to detect the measured variable.