Diagnosis device

Patent metadata

Field	Value
Publication number	US-2016245722-A1
Application number	US-201415025082-A
Country	US
Kind code	A1
Filing date	Sep 26, 2014
Priority date	Sep 27, 2013
Publication date	Aug 25, 2016
Grant date	—

Abstract

A diagnosis device includes: a diesel particulate filter (DPF) collecting particulate matter (PM) in exhaust gas; a resistive type PM sensor provided downstream of the DPF, detecting an amount of PM from current flowing through PM deposited between electrodes. An actual regeneration interval calculator calculating an actual interval from completion of regeneration of the sensor to a start of the next regeneration; a PM slippage amount calculator estimating an amount of PM slippage in exhaust gas that slips through the DPF, assuming the DPF is normal; an estimated regeneration interval calculator calculating, on the basis of the PM slippage amount, an estimated interval from completion of the regeneration of the sensor to the start of the next regeneration; and a DPF failure-normal determination device determining whether the DPF has failed or is normal by comparing the actual interval to the estimated interval.

First claim

1 . A diagnosis device comprising:
a filter that collects a particulate matter in an exhaust gas emitted from an internal combustion engine; a sensor provided at a downstream side of the filter that detects an amount of the particulate matter based on a current flowing through the particulate matter deposited between electrodes, and for which regeneration is possible that combusts and eliminates the particulate matter when the particulate matter deposited between the electrodes reaches a predetermined amount; an actual interval calculator for calculating an actual interval from a completion of the regeneration of the sensor to a start of a next regeneration; a slippage amount estimator for estimating an amount of a particulate matter slippage in the exhaust gas that is emitted from the internal combustion engine and that slips through the filter assuming a collection capability of the filter being normal; an estimated interval calculator for calculating an estimated interval from the completion of the regeneration of the sensor to the start of the next regeneration based on the particulate matter slippage amount; and determination device for determining at least failure of the filter by comparing the actual interval to the estimated interval.

2 . The diagnosis device according to claim 1 , wherein the determination device determines the filter being normal when the regeneration of the filter is not started after a predetermined threshold time elapses from the completion of the calculation of the estimated interval.

3 . The diagnosis device according to claim 1 or 2 , wherein the determination device determines the filter being in failure when the calculation of the estimated interval is not completed after a predetermined threshold time elapses from the completion of the calculation of the actual interval.

4 . The diagnosis device according to claim 1 , wherein the determination device determines the filter being in failure when a difference between the actual interval and the estimated interval exceeds a predetermined maximum threshold.

5 . The diagnosis device according to claim 1 , wherein the determination device determines the filter being in failure when a ratio of the actual interval to the estimated interval exceeds a prescribed maximum threshold.

6 . The diagnosis device according to claim 1 , wherein the slippage amount estimator estimates the particulate matter slippage amount from a model formula having an input value containing an intake and exhaust state quantity that changes depending on an operational status of the internal combustion engine.

7 . The diagnosis device according to claim 1 , wherein the sensor is forcibly regenerated when the internal combustion engine is started.

Assignees

• Isuzu Motors Ltd

Inventors

• Hanawa Satoshi
• Uchiyama Tadashi
• Fujie Hidekazu
• Nakada Teruo
• Murasawa Naoto

Classifications

• G01M15/102 Primary

  by monitoring exhaust gases · CPC title

• F01N2550/04

  Filtering activity of particulate filters · CPC title

• F01N11/00 Primary

  Monitoring or diagnostic devices for exhaust-gas treatment apparatus · CPC title

• F01N2560/05

  the means being a particulate sensor · CPC title

• Y02T10/40

  Engine management systems · CPC title