# US 10,865,747 B2 · EGR malfunction detection system

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- Number: US 10,865,747 B2
- Document ID: US10865747B2
- Status: Granted
- Kind: B2
- Application number: 15/895,349
- Filed: 2018-02-13
- Published: 2018-10-04
- Granted: 2020-12-15
- Earliest claimed: 2017-03-30
- Assignees: Subaru Corporation
- Applicants: Subaru Corporation
- Inventors: Naoki Miura; Yoshiki Isobe
- Web page: https://patentgrep.com/patent/US10865747B2

## CPC

- F02M 26/49: Detecting, diagnosing or indicating an abnormal function of the EGR system
- F02M 26/45: Sensors specially adapted for EGR systems
- F02M 26/52: Systems for actuating EGR valves
- F02D 2200/0406: Intake manifold pressure
- F02M 26/48: EGR valve position sensors (details of the sensor installation in the valve housing F02M26/72)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## Abstract

An EGR malfunction detection system includes an EGR valve configured to open and close an exhaust recirculation path for recirculating an exhaust gas from an exhaust channel to an intake channel of an engine, a measurement unit configured to measure an intake pressure inside the intake channel, a valve controller configured to control the EGR valve, and a malfunction detector configured to detect an anomaly in the exhaust recirculation path in accordance with a measurement unit output and a valve controller output. The malfunction detector determines whether the EGR valve is stuck in accordance with the intake pressures measured when the EGR valve is controlled to open and close. If the EGR valve is stuck, the malfunction detector determines whether the EGR valve is stuck in an open state, stuck in a closed state, or stuck in an intermediate state by comparing the measured pressure with predetermined thresholds.

## Claims

### Claim 1

An EGR malfunction detection system comprising:
an EGR valve configured to open and close an exhaust recirculation path for recirculating an exhaust gas from an exhaust channel to an intake channel of an engine;
a valve controller configured to control the EGR valve;
an intake pressure sensor configured to measure a first intake pressure inside the intake channel when the EGR valve is controlled to be in a closed state by the valve controller, and measure a second intake pressure inside the intake channel when the EGR valve is controlled to be in an open state by the valve controller; and
a processor configured to detect an anomaly in the exhaust recirculation path in accordance with an output from the intake pressures sensor and an output from the valve controller, wherein
the processor determines that the EGR valve is stuck in an open state and outputs a first signal indicating that the EGR valve is stuck in the open state, when the first intake pressure is larger than a first threshold and the second intake pressure is larger than a second threshold that is larger than the first threshold,
the processor determines that the EGR valve is stuck in the closed state and outputs a second signal indicating that the EGR valve is stuck in the closed state, when the first intake pressure is smaller than the first threshold and the second intake pressure is smaller than the second threshold, and
the processor determines that the EGR valve is stuck in an intermediate state and outputs both the first signal and the second signal indicating that the EGR valve is stuck in the intermediate state, when the first intake pressure is larger than the first threshold and the second intake pressure is smaller than the second threshold.

### Claim 2

An EGR malfunction detection system comprising:
an EGR valve configured to open and close an exhaust recirculation path for recirculating an exhaust gas from an exhaust channel to an intake channel of an engine;
a controller configured to control the EGR valve;
a sensor configured to measure a first intake pressure inside the intake channel when the EGR valve is controlled to be in a closed state by the controller, and measure a second intake pressure inside the intake channel when the EGR valve is controlled to be in an open state by the controller; and
circuitry configured to
detect an anomaly in the exhaust recirculation path in accordance with an output from the sensor and an output from the controller, wherein
the circuitry determines that the EGR valve is stuck in an open state and outputs a first signal indicating that the EGR valve is stuck in the open state, when the first intake pressure is larger than a first threshold and the second intake pressure is larger than a second threshold that is larger than the first threshold,
the circuitry determines that the EGR valve is stuck in the closed state and outputs a second signal indicating that the EGR valve is stuck in the closed state, when the first intake pressure is smaller than the first threshold and the second intake pressure is smaller than the second threshold, and
the circuitry determines that the EGR valve is stuck in an intermediate state and outputs both the first signal and the second signal indicating that the EGR valve is stuck in the intermediate state, when the first intake pressure is larger than the first threshold and the second intake pressure is smaller than the second threshold.