# US 11,028,747 B2 · Controller and control method for internal combustion engine

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- Number: US 11,028,747 B2
- Document ID: US11028747B2
- Status: Granted
- Kind: B2
- Application number: 16/526,920
- Filed: 2019-07-30
- Published: 2020-02-13
- Granted: 2021-06-08
- Earliest claimed: 2018-08-07
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Yuki Nose; Yuto Ikeda; Hirofumi Hashinokuchi; Tatsuaki Suzuki; Eiji Ikuta; Yoshiyuki Shogenji; Hirokazu Ando
- Web page: https://patentgrep.com/patent/US11028747B2

## CPC

- F01N 3/0253: {adding fuel to exhaust gases}
- F02D 41/1446: {the characteristics being exhaust temperatures}
- F01N 3/0842: {Nitrogen oxides}
- F01N 3/0871: {using means for controlling, e.g. purging, the absorbents or adsorbents}
- F01N 3/101: {Three-way catalysts}
- F01N 3/2033: {using a fuel burner or introducing fuel into exhaust duct}
- F01N 3/206: {Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents}
- F01N 3/2066: {Selective catalytic reduction [SCR]}
- F01N 3/22: Control of additional air supply only, e.g. using by-passes or variable air pump drives
- F01N 3/30: Arrangements for supply of additional air (control, e.g. using by-passes or variable air pump drives, F01N3/22)
- F01N 9/00: Electrical control of exhaust gas treating apparatus (monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00)
- F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus
- F02D 37/02: one of the functions being ignition
- F02D 41/042: {for stopping the engine}
- F02D 41/123: {the fuel injection being cut-off}
- F02D 41/1439: {characterised by the position of the sensor}
- F02D 41/1454: {the characteristics being an oxygen content or concentration or the air-fuel ratio}
- F02D 41/146: {the characteristics being an NOx content or concentration}
- F02D 41/2454: {Learning of the air-fuel ratio control}
- F02D 41/30: Controlling fuel injection {(F02D41/182, F02D41/24 take precedence)}
- F02D 41/34: with means for controlling injection timing or duration
- F01N 3/0814: {combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts}
- F01N 3/2013: {using electric or magnetic heating means}
- F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent}
- F01N 2240/16: an electric heater, i.e. a resistance heater
- F01N 2430/06: by varying fuel-air ratio, e.g. by enriching fuel-air mixture
- F01N 2430/085: at least a part of the injection taking place during expansion or exhaust stroke
- F01N 2560/025: for measuring or detecting O2, e.g. lambda sensors
- F01N 2560/026: for measuring or detecting NOx
- F01N 2560/06: the means being a temperature sensor
- F01N 2610/02: the substance being ammonia or urea
- F01N 2610/146: Control thereof, e.g. control of injectors or injection valves
- F01N 2900/0602: Electrical exhaust heater signals
- F01N 2900/1602: Temperature of exhaust gas apparatus
- F01N 2900/1804: Properties of secondary air added directly to the exhaust
- F01N 2900/1812: Flow rate
- F02D 41/1441: {Plural sensors}
- 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)
- 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

A controller for an internal combustion engine includes a fuel introduction process of introducing an air-fuel mixture containing fuel injected by a fuel injection valve into an exhaust passage without burning the air-fuel mixture in a cylinder. The fuel introduction processor is configured to perform, during the execution of the fuel introduction process, a determination process of determining whether afterfire, in which the air-fuel mixture burns at an upstream side of a three-way catalyst device in the exhaust passage, has occurred and a stopping process of stopping the fuel introduction process when determining in the determination process that the afterfire has occurred.

## Claims

### Claim 1

A controller configured to control an internal combustion engine, the internal combustion engine includes: (i) a fuel injection valve; (ii) a cylinder into which an air-fuel mixture containing fuel injected by the fuel injection valve is introduced; (iii) an ignition device that ignites the air-fuel mixture introduced into the cylinder with a spark; (iv) an exhaust passage through which gas discharged out of the cylinder flows; and (v) a three-way catalyst device arranged in the exhaust passage, the controller comprising:
a fuel introduction processor configured to execute:
a fuel introduction process of introducing the air-fuel mixture, which contains the fuel injected by the fuel injection valve, into the exhaust passage without burning the air-fuel mixture in the cylinder;
a determination process of determining, during the execution of the fuel introduction process, whether afterfire has occurred, in which the air-fuel mixture burns before flowing into the three-way catalyst device in the exhaust passage; and
a stopping process of stopping, during the execution of the fuel introduction process, the fuel introduction process based on the determining in the determination process that the afterfire has occurred.

### Claim 2 (depends on 1)

The controller according to claim 1, wherein
the internal combustion engine includes an air-fuel ratio sensor arranged at the upstream side of the three-way catalyst device in the exhaust passage, and
the determination process is performed by determining that the afterfire has occurred when an air-fuel ratio detection value of the air-fuel ratio sensor is a value corresponding to a richer air-fuel ratio than a specified determination value.

### Claim 3 (depends on 1)

The controller according to claim 1, wherein
the internal combustion engine includes an exhaust temperature sensor arranged at the upstream side of the three-way catalyst device in the exhaust passage, and
the determination process is performed by determining that the afterfire has occurred when a temperature detection value of the exhaust temperature sensor is greater than or equal to a specified determination value.

### Claim 4 (depends on 1)

The controller according to claim 1, wherein
the internal combustion engine includes a NOx sensor arranged at a downstream side of the three-way catalyst device in the exhaust passage, and
the determination process is performed by determining that the afterfire has occurred when a NOx concentration detection value of the NOx sensor is greater than or equal to a specified determination value.

### Claim 5 (depends on 1)

The controller according to claim 1, wherein the fuel introduction processor is configured to restrict the fuel introduction process from being further executed until an ignition of the internal combustion engine is turned off, when stopping the fuel introduction process in accordance with determining that the afterfire has occurred.

### Claim 6 (depends on 1)

The controller according to claim 1, wherein the fuel introduction processor is configured to reduce a fuel injection amount of the fuel injection valve when executing the fuel introduction process after determining in the determination process that the afterfire has occurred.

### Claim 7 (depends on 1)

The controller according to claim 1, further comprising an air-fuel ratio control unit configured to:
perform, during a combustion operation of the internal combustion engine, an air-fuel ratio feedback control of a fuel injection amount based on an air-fuel ratio detection value of an air-fuel ratio sensor arranged at the upstream side of the three-way catalyst device in the exhaust passage;
learn an air-fuel ratio learning value in accordance with a correction value of the fuel injection amount by the air-fuel ratio feedback control; and
relearn the air-fuel ratio learning value when determining in the determination process that the afterfire has occurred.

### Claim 8 (depends on 1)

The controller according to claim 1, wherein the fuel introduction processor is configured to record, as diagnostic information, a number of times the fuel introduction process has been stopped in accordance with a determination result of the determination process.

### Claim 9

A method for controlling an internal combustion engine, the internal combustion engine including: (i) a fuel injection valve; (ii) a cylinder into which an air-fuel mixture containing fuel injected by the fuel injection valve is introduced; (iii) an ignition device that ignites the air-fuel mixture introduced into the cylinder with a spark; (iv) an exhaust passage through which gas discharged out of the cylinder flows; and (v) a three-way catalyst device arranged in the exhaust passage, the method comprising:
executing a fuel introduction process of introducing the air-fuel mixture, which contains the fuel injected by the fuel injection valve, into the exhaust passage without burning the air-fuel mixture in the cylinder;
determining, during the execution of the fuel introduction process, whether afterfire has occurred, in which the air-fuel mixture burns before flowing into the three-way catalyst device in the exhaust passage; and
stopping, during the execution of the fuel introduction process, the fuel introduction process based on the determining in the determination process that the afterfire has occurred.

### Claim 10

A controller configured to control an internal combustion engine, the internal combustion engine including: (i) a fuel injection valve; (ii) a cylinder into which an air-fuel mixture containing fuel injected by the fuel injection valve is introduced; (iii) an ignition device that ignites the air-fuel mixture introduced into the cylinder with a spark; (iv) an exhaust passage through which gas discharged out of the cylinder flows; and (v) a three-way catalyst device arranged in the exhaust passage, the controller comprising processing circuitry configured to execute:
a fuel introduction process of introducing the air-fuel mixture, which contains the fuel injected by the fuel injection valve, into the exhaust passage without burning the air-fuel mixture in the cylinder;
a determination process of determining, during execution of the fuel introduction process, whether afterfire has occurred, in which the air-fuel mixture burns before flowing into the three-way catalyst device in the exhaust passage; and
a stopping process of stopping, during the execution of the fuel introduction process, the fuel introduction process based on the determining in the determination process that the afterfire has occurred.