CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE AND METHOD FOR CONTROLLING INTERNAL COMBUSTION ENGINE

• US 20130282256A1
• Filed: 09/13/2012
• Published: 10/24/2013
• Est. Priority Date: 04/20/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: HAGARI, Hideki, WATANUKI, Takuo
• Granted Patent: US 9,261,031 B2
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: F02B 33/44 Passages conducting the charge from the pump to the engine inlet, e.g. reservoirs
• CPC Class Codes: F02B 37/16 by bypassing charging air
• CPC Class Codes: F02B 37/18 by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• CPC Class Codes: F02B 39/16 Other safety measures for, or other control of, pumps
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 23/02 the engines being of fuel-injection type
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/18 by measuring intake air flow
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Provided is a control device for an internal combustion engine, capable of controlling acceleration-response characteristics, performing an operation at an optimal fuel-efficiency point, and learning variation factors in an internal combustion engine provided with a supercharger including a wastegate valve. A target throttle-valve upstream pressure is calculated based on a target charging efficiency and a rotation speed. An exhaust-gas flow rate is calculated based on an air/fuel ratio and an intake-airflow rate. A target compressor driving force is calculated based on a target intake-airflow rate and a target throttle-valve upstream pressure. A wastegate-valve control value is calculated from the exhaust-gas flow rate and the target compressor driving force by using the relationship in which the relation expression expressing the characteristics of the exhaust-gas flow rate and the target compressor driving force depends only on the wastegate-valve control value.

Claims

1. A control device for an internal combustion engine including:

a throttle valve provided in an intake path of the internal combustion engine;

a supercharger including a turbine provided in an exhaust path and a compressor provided in the intake path on an upstream side of the throttle valve, for rotating integrally with the turbine;

a wastegate valve provided in a bypass passage for bypassing the turbine; and

a wastegate-valve driving section for driving the wastegate valve to change a flow-path sectional area of the bypass passage,

the control device comprising a wastegate-valve control part including;

a target throttle-valve upstream pressure computing section for calculating a target throttle-valve upstream pressure corresponding to a target value of a pressure on the upstream side of the throttle valve based on a target charging efficiency serving as a target value of a charging efficiency of the internal combustion engine and a rotation speed of the internal combustion engine;

an exhaust-gas flow-rate computing section for calculating an exhaust-gas flow rate based on an air/fuel ratio of the internal combustion engine and an actual in-cylinder fresh-air amount;

a target compressor driving-force computing section for calculating a target compressor driving force based on a target intake airflow rate serving as a target value of an intake airflow rate and the target throttle-valve upstream pressure; and

a wastegate-valve opening-degree computing section for calculating a wastegate-valve control value based on the exhaust-gas flow rate and the target compressor driving force,

wherein the wastegate-valve control part uses a relationship of characteristics of the exhaust-gas flow rate and the target compressor driving force, depending only on the wastegate-valve control value, to calculate the wastegate-valve control value so as to control the wastegate-valve driving section.

2. The control device for an internal combustion engine according to claim 1, wherein:

the wastegate-valve control part further includes a target inlet-manifold pressure computing section for calculating an actual volumetric-efficiency correction factor corresponding to a ratio of the intake airflow rate of air to be sucked into a cylinder based on the intake airflow rate, and on an inlet-manifold pressure and an intake-air temperature in the intake path so as to calculate a target inlet-manifold pressure based on the actual volumetric-efficiency correction factor, the intake-air temperature, the target charging efficiency, and a law of physics relating to an air state; and

the target throttle-valve upstream pressure computing section calculates the target throttle-valve upstream pressure based on the target inlet-manifold pressure including characteristics in which the throttle-valve upstream pressure becomes higher than the inlet-manifold pressure, and environmental corrections in accordance with the intake-air temperature and a water temperature.

3. The control device for an internal combustion engine according to claim 1, wherein:

the wastegate-valve control part further includes an actual compressor driving-force calculating section for calculating an actual compressor driving force based on a throttle-valve upstream pressure corresponding to an intake-air pressure on the upstream side of the throttle valve and the intake airflow rate; and

the wastegate-valve opening-degree computing section performs PID control in accordance with a difference between the actual compressor driving force and the target compressor driving force to calculate a feedback correction amount for the wastegate-valve control value.

4. The control device for an internal combustion engine according to claim 2, wherein:

the wastegate-valve control part further includes an actual compressor driving-force calculating section for calculating an actual compressor driving force based on a throttle-valve upstream pressure corresponding to an intake-air pressure on the upstream side of the throttle valve and the intake airflow rate; and

the wastegate-valve opening-degree computing section performs PID control in accordance with a difference between the actual compressor driving force and the target compressor driving force to calculate a feedback correction amount for the wastegate-valve control value.

5. The control device for an internal combustion engine according to claim 1, wherein the wastegate-valve opening-degree computing section calculates a feedback learning amount for the wastegate-valve control valve with respect to a quantitative deviation amount of the wastegate-valve control value so as to perform a learning correction on the actual compressor driving force and the wastegate-valve control value.

6. The control device for an internal combustion engine according to claim 2, wherein the wastegate-valve opening-degree computing section calculates a feedback learning amount for the wastegate-valve control valve with respect to a quantitative deviation amount of the wastegate-valve control value so as to perform a learning correction on the actual compressor driving force and the wastegate-valve control value.

7. The control device for an internal combustion engine according to claim 3, wherein the wastegate-valve opening-degree computing section calculates a feedback learning amount for the wastegate-valve control valve with respect to a quantitative deviation amount of the wastegate-valve control value so as to perform a learning correction on the actual compressor driving force and the wastegate-valve control value.

8. The control device for an internal combustion engine according to claim 4, wherein the wastegate-valve opening-degree computing section calculates a feedback learning amount for the wastegate-valve control valve with respect to a quantitative deviation amount of the wastegate-valve control value so as to perform a learning correction on the actual compressor driving force and the wastegate-valve control value.

9. The control device for an internal combustion engine according to claim 1, wherein each of the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section calculates a correction ratio for a standard state of an atmospheric pressure and a correction ratio for a standard state of an intake-air temperature in the intake path so that the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section respectively calculate the target compressor driving force, the exhaust-gas flow rate, and the actual compressor driving force by using environmental correction amounts corresponding to the calculated correction ratios.

10. The control device for an internal combustion engine according to claim 2, wherein each of the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section calculates a correction ratio for a standard state of an atmospheric pressure and a correction ratio for a standard state of an intake-air temperature in the intake path so that the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section respectively calculate the target compressor driving force, the exhaust-gas flow rate, and the actual compressor driving force by using environmental correction amounts corresponding to the calculated correction ratios.

11. The control device for an internal combustion engine according to claim 3, wherein each of the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section calculates a correction ratio for a standard state of an atmospheric pressure and a correction ratio for a standard state of an intake-air temperature in the intake path so that the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section respectively calculate the target compressor driving force, the exhaust-gas flow rate, and the actual compressor driving force by using environmental correction amounts corresponding to the calculated correction ratios.

12. The control device for an internal combustion engine according to claim 4, wherein each of the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section calculates a correction ratio for a standard state of an atmospheric pressure and a correction ratio for a standard state of an intake-air temperature in the intake path so that the target compressor driving-force computing section, the exhaust-gas flow-rate computing section, and the actual compressor driving-force computing section respectively calculate the target compressor driving force, the exhaust-gas flow rate, and the actual compressor driving force by using environmental correction amounts corresponding to the calculated correction ratios.

13. The control device for an internal combustion engine according to claim 1, wherein:

the wastegate-valve driving section comprises a pressure-type wastegate valve; and

the wastegate-valve control part controls a duty ratio of the wastegate valve, for controlling a pressure to be applied to a diaphragm of the wastegate valve with the wastegate-valve control value.

14. The control device for an internal combustion engine according to claim 2, wherein:

the wastegate-valve driving section comprises a pressure-type wastegate valve; and

the wastegate-valve control part controls a duty ratio of the wastegate valve, for controlling a pressure to be applied to a diaphragm of the wastegate valve with the wastegate-valve control value.

15. The control device for an internal combustion engine according to claim 3, wherein:

the wastegate-valve driving section comprises a pressure-type wastegate valve; and

the wastegate-valve control part controls a duty ratio of the wastegate valve, for controlling a pressure to be applied to a diaphragm of the wastegate valve with the wastegate-valve control value.

16. The control device for an internal combustion engine according to claim 1, wherein:

the wastegate-valve driving section comprises an electric-type wastegate valve; and

the wastegate-valve control part controls an opening degree of the wastegate valve with the wastegate-valve control value.

17. The control device for an internal combustion engine according to claim 2, wherein:

the wastegate-valve driving section comprises an electric-type wastegate valve; and

the wastegate-valve control part controls an opening degree of the wastegate valve with the wastegate-valve control value.

18. The control device for an internal combustion engine according to claim 3, wherein:

the wastegate-valve driving section comprises an electric-type wastegate valve; and

the wastegate-valve control part controls an opening degree of the wastegate valve with the wastegate-valve control value.

19. A control method for an internal combustion engine including:

a throttle valve provided in an intake path of the internal combustion engine;

a supercharger including a turbine provided in an exhaust path and a compressor provided in the intake path on an upstream side of the throttle valve, for rotating integrally with the turbine;

a wastegate valve provided in a bypass passage for bypassing the turbine; and

a wastegate-valve driving section for driving the wastegate valve to change a flow-path sectional area of the bypass passage, the control method comprising;

calculating a target throttle-valve upstream pressure corresponding to a target value of a pressure on the upstream side of the throttle valve based on a target charging efficiency serving as a target value of a charging efficiency of the internal combustion engine and a rotation speed of the internal combustion engine;

calculating an exhaust-gas flow rate based on an air/fuel ratio of the internal combustion engine and an actual in-cylinder fresh-air amount;

calculating a target compressor driving force based on a target intake airflow rate serving as a target value of an intake airflow rate and the target throttle-valve upstream pressure; and

calculating a wastegate-valve control value (WG) based on the exhaust-gas flow rate and the target compressor driving force,

wherein a relationship of characteristics of the exhaust-gas flow rate and the target compressor driving force, depending only on the wastegate-valve control value, is used to calculate the wastegate-valve control value so as to control the wastegate-valve driving section.