CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

• US 20100049422A1
• Filed: 04/30/2008
• Published: 02/25/2010
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Moriya, Hidenori
• Granted Patent: US 8,286,610 B2
• Time in Patent Office: Days
• US Class Current: 701/103
• CPC Class Codes: F02D 19/0623 Failure diagnosis or prevention; Safety measures; Testing
• CPC Class Codes: F02D 19/0689 for in-cylinder direct injection
• CPC Class Codes: F02D 19/084 Blends of gasoline and alcohols, e.g. E85
• CPC Class Codes: F02D 19/088 by estimation, i.e. without using direct measurements of a corresponding sensor
• CPC Class Codes: F02D 2200/0612 determined by estimation
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In an internal combustion engine control device having an air-fuel ratio control device that controls the fuel injection amount so that the air-fuel ratio of exhaust gas of an internal combustion engine approaches a target stoichiometric air-fuel ratio, the control device further includes a device that calculates the lower calorific value of fuel, and a device that sets the target stoichiometric air-fuel ratio from the calculated lower calorific value based on a known relationship between the lower calorific value and the stoichiometric air-fuel ratio. It becomes possible to perform the air-fuel ratio control according to the fuel property by utilizing the relationship between the calorific value and the stoichiometric air-fuel ratio.

Claims

1. An internal combustion engine control device, comprising:

an air-fuel ratio sensor that detects air-fuel ratio of an exhaust gas of an internal combustion engine;

an air-fuel ratio control device that controls a fuel injection amount so that the air-fuel ratio detected by the air-fuel ratio sensor approaches a target stoichiometric air-fuel ratio;

a lower calorific value calculation device that calculates a lower calorific value of a fuel; and

a target stoichiometric air-fuel ratio setting device that sets the target stoichiometric air-fuel ratio from the calculated lower calorific value based on a known relationship between the lower calorific value and a stoichiometric air-fuel ratio.

2. The control device according to claim 1, further comprising:

an in-cylinder pressure sensor that detects pressure in a cylinder of the internal combustion engine, wherein

the lower calorific value calculation device includes a pressure-based lower calorific value calculation device that calculates the lower calorific value by using a heat generation amount calculated based on a detected in-cylinder pressure value that is detected by the in-cylinder pressure sensor.

3. The control device according to claim 1, further comprising:

a stoichiometric air-fuel ratio calculation device that calculates the stoichiometric air-fuel ratio based on the air-fuel ratio detected value detected by the air-fuel ratio sensor, wherein

the lower calorific value calculation device includes an air-fuel ratio-based lower calorific value calculation device that calculates the lower calorific value of the fuel from the stoichiometric air-fuel ratio calculated by the stoichiometric air-fuel ratio calculation device, based on the known relationship between the lower calorific value and the stoichiometric air-fuel ratio.

4. The control device according to claim 3, further comprising:

an O₂ sensor that detects oxygen concentration in the exhaust gas of the internal combustion engine, wherein

the air-fuel ratio-based lower calorific value calculation device calculates the lower calorific value based on a weighted average stoichiometric air-fuel ratio calculated by weighting the air-fuel ratio detected by the air-fuel ratio sensor with an output value of the O₂ sensor.

5. The control device according to claim 3, further comprising:

a diagnostic device that diagnoses at least one of the air-fuel ratio-based lower calorific value calculation device and the pressure-based lower calorific value calculation device based on comparison between the lower calorific value calculated by the air-fuel ratio-based lower calorific value calculation device and the lower calorific value calculated by the pressure-based lower calorific value calculation device.

9. The control device according to claim 4, further comprising:

a diagnostic device that diagnoses at least one of the air-fuel ratio-based lower calorific value calculation device and the pressure-based lower calorific value calculation device based on comparison between the lower calorific value calculated by the air-fuel ratio-based lower calorific value calculation device and the lower calorific value calculated by the pressure-based lower calorific value calculation device.

6. An internal combustion engine control device, comprising:

an air-fuel ratio sensor that detects air-fuel ratio of an exhaust gas of an internal combustion engine;

a stoichiometric air-fuel ratio calculation device that calculates a stoichiometric air-fuel ratio based on the air-fuel ratio detected value detected by the air-fuel ratio sensor; and

an air-fuel ratio-based lower calorific value calculation device that calculates a lower calorific value of a fuel from the stoichiometric air-fuel ratio calculated by the stoichiometric air-fuel ratio calculation device, based on a known relationship between the lower calorific value and the stoichiometric air-fuel ratio.

7. The control device according to claim 6, further comprising:

an O₂ sensor that detects oxygen concentration in the exhaust gas of the internal combustion engine, wherein

the air-fuel ratio-based lower calorific value calculation device calculates the lower calorific value based on a weighted average stoichiometric air-fuel ratio calculated by weighting the air-fuel ratio detected by the air-fuel ratio sensor with an output value of the O₂ sensor.

8. The control device according to claim 6, further comprising:

an in-cylinder pressure sensor that detects pressure in a cylinder of the internal combustion engine;

a pressure-based lower calorific value calculation device that calculates the lower calorific value based on the detected in-cylinder pressure value; and

a diagnostic device that diagnoses at least one of the air-fuel ratio-based lower calorific value calculation device and the pressure-based lower calorific value calculation device based on comparison between the lower calorific value calculated by the air-fuel ratio-based lower calorific value calculation device and the lower calorific value calculated by the pressure-based lower calorific value calculation device.

10. The control device according to claim 7 further comprising:

an in-cylinder pressure sensor that detects pressure in a cylinder of the internal combustion engine;

a pressure-based lower calorific value calculation device that calculates the lower calorific value based on the detected in-cylinder pressure value, and

a diagnostic device that diagnoses at least one of the air-fuel ratio-based lower calorific value calculation device and the pressure-based lower calorific value calculation device based on comparison between the lower calorific value calculated by the air-fuel ratio-based lower calorific value calculation device and the lower calorific value calculated by the pressure-based lower calorific value calculation device.