# US 11,441,504 B2 · Controller and control method for internal combustion engine

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- Number: US 11,441,504 B2
- Document ID: US11441504B2
- Status: Granted
- Kind: B2
- Application number: 17/559,690
- Filed: 2021-12-22
- Published: 2022-07-14
- Granted: 2022-09-13
- Earliest claimed: 2021-01-08
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Hitoki Sugimoto
- Web page: https://patentgrep.com/patent/US11441504B2

## CPC

- F02D 41/1475: {Regulating the air fuel ratio at a value other than stoichiometry}
- F01N 3/08: for rendering innocuous (using electric or electrostatic separators F01N3/01; chemical aspects B01D53/92)
- F01N 11/007: {the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus}
- F02D 17/02: Cutting-out (cutting-out engines in multiple engine arrangements F02D25/04)
- F02D 41/0087: {Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123)}
- F02D 41/025: {by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus}
- F02D 41/0295: {Control according to the amount of oxygen that is stored on the exhaust gas treating apparatus}
- F02D 41/1439: {characterised by the position of the sensor}
- F02D 41/1444: {characterised by the characteristics of the combustion gases}
- F02D 41/1454: {the characteristics being an oxygen content or concentration or the air-fuel ratio}
- F02D 41/222: {relating to the failure of sensors or parameter detection devices}
- F01N 2430/02: by cutting out a part of engine cylinders
- F01N 2550/02: Catalytic activity of catalytic converters
- F01N 2560/025: for measuring or detecting O2, e.g. lambda sensors
- F01N 2560/06: the means being a temperature sensor
- F01N 2560/14: having more than one sensor of one kind
- F01N 2900/0416: using the state of a sensor, e.g. of an exhaust gas sensor
- F01N 2900/1624: Catalyst oxygen storage capacity
- F02D 2200/0816: Oxygen storage capacity
- 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)

## Abstract

A controller for an internal combustion engine includes processing circuitry that executes a richening process until an exhaust sensor detects exhaust gas having a rich air-fuel ratio. The processing circuitry executes an air supplying process to supply a catalytic converter with air until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio. The processing circuitry cumulates the amount of air supplied to the catalytic converter until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio in the air supplying process. The air supplying process includes stopping fuel supplied to the one or more of the cylinders and performing combustion at an air-fuel ratio that is less than or equal to the stoichiometric air-fuel ratio in the remaining one or more of the cylinders.

## Claims

### Claim 1

A controller for an internal combustion engine, wherein the internal combustion engine includes cylinders, a catalytic converter configured to purify exhaust gas and configured to store oxygen, and an exhaust sensor located at a downstream side of the catalytic converter and configured to detect oxygen, the controller comprising:
processing circuitry, wherein:
the processing circuitry is configured to execute a richening process that supplies the catalytic converter with exhaust gas having an air-fuel ratio that is rich until the exhaust sensor detects that the exhaust gas has a rich air-fuel ratio;
after the exhaust sensor detects that the exhaust gas has a rich air-fuel ratio in the richening process, the processing circuitry is configured to execute an air supplying process that supplies the catalytic converter with air until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio;
the processing circuitry is configured to execute a stored oxygen capacity estimating process that estimates a stored oxygen capacity of the catalytic converter by cumulating an amount of air supplied to the catalytic converter until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio in the air supplying process; and
the air supplying process includes stopping fuel supplied to one or more of the cylinders and performing combustion at an air-fuel ratio that is less than or equal to a stoichiometric air-fuel ratio in remaining one or more of the cylinders so that the cylinders supply the catalytic converter with exhaust gas, which as a whole, is controlled to have a lean air-fuel ratio.

### Claim 2 (depends on 1)

The controller according to claim 1, wherein the processing circuitry is configured to determine that the catalytic converter is defective when a cumulative air amount is less than a first threshold value, the cumulative air amount being the amount of air cumulated until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio in the air supplying process.

### Claim 3 (depends on 1)

The controller according to claim 1, wherein the processing circuitry is configured to determine that the catalytic converter is functioning normally when a cumulative air amount is greater than or equal to a first threshold value, the cumulative air amount being the amount of air cumulated until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio in the air supplying process.

### Claim 4 (depends on 2)

The controller according to claim 2, wherein the processing circuitry is configured to determine that the exhaust sensor is functioning normally when the cumulative air amount is less than or equal to a second threshold value that is greater than the first threshold value.

### Claim 5 (depends on 2)

The controller according to claim 2, wherein the processing circuitry is configured to determine that the exhaust sensor is defective when the cumulative air amount is greater than a second threshold value that is greater than the first threshold value.

### Claim 6 (depends on 1)

The controller according to claim 1, wherein the air supplying process includes stopping fuel supplied to the one or more of the cylinders and performing combustion at the stoichiometric air-fuel ratio in the remaining one or more of the cylinders.

### Claim 7

A method for controlling an internal combustion engine, wherein the internal combustion engine includes cylinders, a catalytic converter configured to purify exhaust gas and configured to store oxygen, and an exhaust sensor located at a downstream side of the catalytic converter and configured to detect oxygen, the method comprising:
executing a richening process that supplies the catalytic converter with exhaust gas having an air-fuel ratio that is rich until the exhaust sensor detects that the exhaust gas has a rich air-fuel ratio;
after the exhaust sensor detects that the exhaust gas has a rich air-fuel ratio in the richening process, executing an air supplying process that supplies the catalytic converter with air until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio; and
executing a stored oxygen capacity estimating process that estimates a stored oxygen capacity of the catalytic converter by cumulating an amount of air supplied to the catalytic converter until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio in the air supplying process;
wherein the air supplying process includes stopping fuel supplied to one or more of the cylinders and performing combustion at an air-fuel ratio that is less than or equal to a stoichiometric air-fuel ratio in remaining one or more of the cylinders so that the cylinders supply the catalytic converter with exhaust gas, which as a whole, is controlled to have a lean air-fuel ratio.