Control method and control apparatus for internal combustion engine

Patent metadata

Field	Value
Publication number	US-11920529-B2
Application number	US-202117632960-A
Country	US
Kind code	B2
Filing date	Apr 15, 2021
Priority date	Apr 15, 2021
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

A first output limit value is determined as an intersection point of a knock-limit output line which is set according to an exhaust gas recirculation rate and ignition timing and an exhaust-temperature-limit output line which is set according to the exhaust gas recirculation rate and ignition timing; a second output limit value is determined as an intersection point of the knock-limit output line and an air-quantity-limit output line which is set according to the exhaust gas recirculation rate, ignition timing and atmospheric pressure; and a third output limit value is determined as an intersection point of the knock-limit output line and a thermal-management-limit output line which is set according to the exhaust gas recirculation rate, ignition timing and vehicle running speed. A value of the exhaust gas recirculation rate at which the condition “P 1 ≥P 2 or P 1 ≥P 3 ” is satisfied is set as a target exhaust gas recirculation rate.

First claim

The invention claimed is:

1. A control method of an internal combustion engine mounted on a vehicle and comprising an exhaust gas recirculation device,
the internal combustion engine having: a first output limit which is associated with at least a knock limit and whose value increases with increase of an exhaust gas recirculation rate; and a second output limit which is associated with an output limiting factor including an atmospheric pressure or vehicle running speed and whose value decreases with decrease of the output limiting factor and with increase of the exhaust gas recirculation rate,
the control method comprising setting a target exhaust gas recirculation rate at which the first output limit becomes equal to the second output limit and controlling the exhaust recirculation device according to the target exhaust gas recirculation rate.

2. The control method of the internal combustion engine according to claim 1 , wherein the control method comprises setting a target output value at which the first output limit and the second output limit become equal to each other and controlling output of the internal combustion engine according to the target output value.

3. The control method of the internal combustion engine according to claim 1 , wherein the first output limit is determined from the knock limit and an exhaust temperature limit such that the value of the first output limit corresponds to the exhaust gas recirculation rate.

4. The control method of the internal combustion engine according to claim 1 , wherein the second output limit is defined as an air quantity limit depending on a turbocharger and correlated with an atmospheric pressure and the exhaust gas recirculation rate.

5. The control method of the internal combustion engine according to claim 1 , wherein the second output limit is defined as an output limit in terms of thermal management based on at least change in amount of heat radiation from a cooling system caused due to the vehicle running speed and change in amount of heat radiation to the cooling system caused by exhaust gas recirculation.

6. The control method of the internal combustion engine according to claim 1 , wherein the second output limit is determined as a lower value among an output limit associated with the atmospheric pressure and an output limit associated with the vehicle running speed.

7. The control method of the internal combustion engine according to claim 1 ,
wherein the first output limit is determined as an intersection point of a knock-limit output line which is set according to the exhaust gas recirculation rate and an ignition timing and an exhaust-temperature-limit output line which is set according to the exhaust gas recirculation rate and the ignition timing, and
wherein the second output limit is determined as an intersection point of the knock-limit output line and an air-quantity-limit output line which is set according to the exhaust gas recirculation rate, the ignition timing and the atmospheric pressure.

8. The control method of the internal combustion engine according to claim 1 ,
wherein the first output limit is determined as an intersection point of a knock-limit output line which is set according to the exhaust gas recirculation rate and an ignition timing and an exhaust-temperature-limit output line which is set according to the exhaust gas recirculation rate and the ignition timing, and
wherein the second output limit is determined as an intersection point of the knock-limit output line and a thermal-management-limit output line which is set according to the exhaust gas recirculation rate, the ignition timing and the vehicle running speed.

9. The control method of the internal combustion engine according to claim 1 ,
wherein the first output limit is determined as an intersection point of a knock-limit output line which is set according to the exhaust gas recirculation rate and an ignition timing and an exhaust-temperature-limit output line which is set according to the exhaust gas recirculation rate and the ignition timing,
wherein one type of the second output limit is determined as an intersection point of the knock-limit output line and an air-quantity-limit output line which is set according to the exhaust gas recirculation rate, the ignition timing and the atmospheric pressure,
wherein another type of the second output limit is determined as an intersection point of the knock-limit output line and a thermal-management-limit output line which is set according to the exhaust gas recirculation rate, the ignition timing and the vehicle running speed, and
wherein the exhaust gas recirculation device is controlled according to the target exhaust gas recirculation rate at which the first output limit becomes equal to a lower value among said one and another types of the second output limit.

10. A control apparatus for an internal combustion engine mounted on a vehicle and comprising an exhaust gas recirculation device, the control apparatus comprising:
a controller configured to control operation of the exhaust gas recirculation device and output of the internal combustion engine; and
one sensor or a plurality of sensors provided to detect information about an output limiting factor including an atmospheric pressure or vehicle running speed,
the internal combustion engine having: a first output limit which is associated with at least a knock limit and whose value increases with increase of an exhaust gas recirculation rate; and a second output limit whose value decreases with decrease of the output limiting factor and with increase of the exhaust gas recirculation rate,
wherein the controller is configured to set a target exhaust gas recirculation rate at which the first output limit becomes equal to the second output limit and control the exhaust gas recirculation rate according to the target exhaust gas recirculation rate.

Assignees

• Nissan Motor

Inventors

• Kodama Takayoshi
• Iwabuchi Yoshihiko

Classifications

• F02D41/0055 Primary

  Special engine operating conditions, e.g. for regeneration of exhaust gas treatment apparatus · CPC title

• F02D41/0052

  Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount · CPC title

• F02D2200/501

  Vehicle speed · CPC title

• F02D2200/703

  Atmospheric pressure · CPC title

• F02D35/027 Primary

  using knock sensors · CPC title