# US 10,119,489 B2 · Diagnostic device and diagnostic system

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- Number: US 10,119,489 B2
- Document ID: US10119489B2
- Status: Granted
- Kind: B2
- Application number: 15/553,940
- Filed: 2016-02-24
- Published: 2018-02-08
- Granted: 2018-11-06
- Earliest claimed: 2015-02-27
- Assignees: Isuzu Motors Limited
- Applicants: Isuzu Motors Limited
- Inventors: Ken Hasegawa; Hirotaka Takahashi; Masanobu Minezawa
- Web page: https://patentgrep.com/patent/US10119489B2

## CPC

- F02D 41/222: {relating to the failure of sensors or parameter detection devices}
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus
- F01N 13/008: {Mounting or arrangement of exhaust sensors in or on exhaust apparatus (sensor arrangements for engine control F02D41/1439)}
- F02D 9/04: concerning exhaust conduits (throttle valves, or arrangements thereof in conduits F02D9/08)
- F02D 41/123: {the fuel injection being cut-off}
- F02D 41/1445: {the characteristics being related to the exhaust flow}
- F02D 41/1461: {of the exhaust gases emitted by the engine}
- F02D 41/1463: {of the exhaust gases downstream of exhaust gas treatment apparatus}
- F02D 41/2441: {characterised by the learning conditions}
- F02D 41/2448: {Prohibition of learning}
- F02D 41/2474: {Characteristics of sensors}
- F02D 41/3005: {Details not otherwise provided for}
- G01M 15/104: {using oxygen or lambda-sensors (testing catalytic converters F01N3/18, F01N11/007)}
- G01N 33/0037: {NOx}
- F01N 2240/36: an exhaust flap
- F01N 2560/026: for measuring or detecting NOx
- F01N 2610/02: the substance being ammonia or urea
- F01N 2900/1402: Exhaust gas composition
- F01N 2900/1411: Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate
- F02D 13/04: using engine as brake
- F02D 2200/602: Pedal position
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02T 10/12: Improving ICE efficiencies
- Y02T 10/40: Engine management systems
- 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)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A diagnostic device for a sensor 100 provided in an exhaust passage 11 of an internal combustion engine 10 of a vehicle and detecting nitrogen compounds in exhaust gas, the diagnostic device including an offset diagnosis unit 42 which diagnoses, during deceleration of the vehicle in which the internal combustion engine 10 stops fuel injection, an offset amount of a sensor value of the sensor 100 from a zero point based on the sensor value of the sensor value, and a diagnosis prohibition unit 44 which prohibits the diagnosing of the offset amount when a flow rate of the exhaust gas of the internal combustion engine 10 rapidly increases while the offset amount is diagnosed by the offset diagnosis unit 42.

## Claims

### Claim 1

A diagnostic device for a sensor provided in an exhaust passage of an internal combustion engine of a vehicle and detecting nitrogen compounds in exhaust gas, the diagnostic device comprising:
an offset diagnosis unit which diagnoses, during deceleration of the vehicle in which the internal combustion engine stops fuel injection, an offset amount of a sensor value of the sensor from a zero point based on the sensor value of the sensor; and
a diagnosis prohibition unit which prohibits the diagnosing of the offset amount when a flow rate of the exhaust gas of the internal combustion engine rapidly increases while the offset amount is diagnosed by the offset diagnosis unit.

### Claim 2 (depends on 1)

The diagnostic device according to claim 1,
wherein the diagnosis prohibition unit prohibits the diagnosing of the offset amount when an exhaust brake device is switched from an operation state to a non-operation state.

### Claim 3 (depends on 2)

The diagnostic device according to claim 2,
wherein the diagnosis prohibition unit prohibits the diagnosing of the offset amount until a predetermined period of time has passed after switching to the non-operation state when the exhaust brake device is switched from the operation state to the non-operation state.

### Claim 4

A diagnostic system comprising:
a sensor provided in an exhaust passage of an internal combustion engine of a vehicle and detecting nitrogen compounds in exhaust gas; and
a control unit,
wherein the control unit is operated to execute:
an offset diagnosis process of diagnosing, during deceleration of the vehicle in which the internal combustion engine stops fuel injection, an offset amount of a sensor value of the sensor from a zero point based on the sensor value of the sensor; and
a diagnosis prohibition process of prohibiting the diagnosing of the offset amount when a flow rate of the exhaust gas of the internal combustion engine rapidly increases while the offset amount is diagnosed by the offset diagnosis process.

### Claim 5 (depends on 4)

The diagnostic system according to claim 4,
wherein, in the diagnosis prohibition process, the control unit prohibits the diagnosing of the offset amount when an exhaust brake device is switched from an operation state to a non-operation state.

### Claim 6 (depends on 5)

The diagnostic system according to claim 5,
wherein, in the diagnosis prohibition process, the control unit prohibits the diagnosing of the offset amount until a predetermined period of time has passed after switching to the non-operation state when the exhaust brake device is switched from the operation state to the non-operation state.