Sensor controller

Patent metadata

Field	Value
Publication number	US-9316574-B2
Application number	US-201113183585-A
Country	US
Kind code	B2
Filing date	Jul 15, 2011
Priority date	Aug 6, 2010
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

A sensor controller for a particulate matter detection sensor includes a heater configured to heat an attachment portion so as to burn and remove particulate matter attached to the attachment portion, a learning portion for obtaining a sensor detection value immediately after burning and removing the particulate matter due to heating of the heater. The leaning portion calculates a sensor standard value based on the obtained sensor detection value in a state where the particulate matter is removed, and stores the sensor standard value as a learning value. Furthermore, a correcting portion corrects the sensor detection value based on the sensor standard value stored by the learning portion.

First claim

What is claimed is:

1. A sensor controller system configured to control the operation of an engine,
the sensor controller system comprising:
a particulate matter detection sensor; and
a sensor controller comprising:
a heater connected to the particulate matter detection sensor, the particulate matter detection sensor including an attachment portion to which conductive particulate matter contained in gas is attached, and a pair of opposed electrodes spaced from each other at the attachment portion, the heater heating, via the pair of opposed electrodes, the attachment portion so as to burn and remove the particulate matter attached to the attachment portion; and
a computer processor connected to the particular matter detection sensor and the engine, the computer processor performing at least
obtaining a sensor detection value, corresponding to a resistance between the pair of opposed electrodes, outputted from the particulate matter detection sensor immediately after the burning and removing the particulate matter due to heating of the heater,
calculating a first sensor standard value based on the obtained sensor detection value in a state where the particulate matter is removed from the attachment portion,
storing the first sensor standard value as a first learning value
correcting a sensor detection value outputted from the particulate matter detection sensor based on the stored first sensor standard value,
calculating an amount of attached particulate matter based on the corrected sensor detection value,
outputting a control signal to the engine based on the calculated amount of attached particulate matter, and
controlling the operation of the engine.

2. The sensor controller system according to claim 1 , wherein
the computer processor is configured to further perform calculating correction values that are different from each other in accordance with the amounts of the attached particulate matter, based on the first sensor standard value, and correcting the sensor detection value by using the calculated correction values.

3. The sensor controller system according to claim 1 , wherein the computer processor is configured to further perform
diagnosis of abnormality of the particulate matter detection sensor based on the sensor detection value obtained immediately after burning and removing of the particulate matter.

4. The sensor controller system according to claim 1 , wherein
the computer processor is configured to further perform obtaining the sensor detection value in a state where the resistance between the pair of opposed electrodes varies to be increased and a variation amount of the resistance is within a predetermined range, and calculating the first sensor standard value based on the obtained sensor detection value.

5. The sensor controller system according to claim 1 , wherein
the particulate matter detection sensor is connected to a signal output circuit such that the sensor detection value is changeable in a predetermined output range by the signal output circuit,
the learning means obtains the sensor detection value in a burning of the particulate matter due to heating of the heater, calculates a second sensor standard value in a state where the resistance between the pair of opposed electrodes is reduced based on the obtained sensor detection value, and stores the second sensor standard value as a second learning value; and
the correcting means corrects the sensor detection value based on at least one of the first sensor standard value and the second sensor standard value stored by the learning means.

6. The sensor controller system according to claim 5 , wherein
the signal output circuit is a voltage-dividing circuit that has an electrode resistance corresponding to the resistance of the pair of opposed electrodes, a shunt resistance and an electrical source portion,
the voltage-dividing circuit is configured to output a voltage at a middle point between the electrode resistance and the shunt resistance as the sensor detection value, and
the learning means obtains the voltage at the middle point in the burning of the particulate matter, and calculates the second sensor standard value based on the voltage at the middle point.

7. The sensor controller system according to claim 6 , wherein
the correcting means calculates correction values that are different from each other in accordance with the amounts of the attached particulate matter based on the second sensor standard value, and corrects the sensor detection value by using the calculated correction values.

8. The sensor controller system according to claim 5 , further comprising
abnormality diagnosis means for performing diagnosis of abnormality of the particulate matter detection sensor based on the sensor detection value in the burning of the particulate matter.

9. The sensor controller system according to claim 5 , wherein
the learning means obtains the sensor detection value in a state where the resistance between the pair of opposed electrodes varies to be decreased and a variation amount of the resistance is within a predetermined range, and calculates the second sensor standard value based on the obtained sensor detection value.

10. The sensor controller system according to claim 2 , wherein
the computer processor is configured to further perform calculating the correction value based on the first sensor standard value, such that the correction value is smaller as the amount of the attached particulate matter becomes larger.

11. The sensor controller system according to claim 7 , wherein
the correcting means calculates the correction value based on the second sensor standard value such that the correction value is smaller as the amount of the attached particulate matter becomes smaller and is larger as the amount of the attached particulate matter becomes larger.

12. The sensor controller system according to claim 4 , wherein the particulate matter detection sensor further comprises
a voltage-dividing circuit that comprises the pair of opposed electrodes of the attachment portion, a shunt resistance and an electrical source portion, and has an electrode resistance corresponding to the resistance of the pair of opposed electrodes, wherein
the voltage-dividing circuit is configured to output a voltage at a middle point between the electrode resistance and the shunt resistance as the sensor detection value, and wherein
the computer processor is further configured to perform obtaining the voltage at the middle point immediately after the burning and removing of the particulate matter, and calculating the first sensor standard value based on the voltage at the middle point.

Assignees

• Sakamoto Yuuki
• Matsuoka Mikiyasu
• Matsumoto Yuuzou
• Denso Corp

Inventors

• Sakamoto Yuuki
• Matsuoka Mikiyasu
• Matsumoto Yuuzou

Classifications

• G01N15/0656 Primary

  using electric, e.g. electrostatic methods or magnetic methods (by investigating individual particles G01N15/1031, G01N15/12) · CPC title