Control device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10066557-B2
Application number	US-201715804450-A
Country	US
Kind code	B2
Filing date	Nov 6, 2017
Priority date	Nov 25, 2016
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A control device for an internal combustion engine adjusts the flow rate ratio between an amount of exhaust gas flowing to an exhaust gas recirculation cooler and an amount of exhaust gas flowing to a bypass passage, which bypasses the exhaust gas recirculation cooler, such that the amount of exhaust gas flowing to the exhaust gas recirculation cooler becomes zero during (i) a predetermined period from a point in time at which the exhaust gas recirculation operation shifts to execution, (ii) a period in which fuel cut is performed and the bed temperature of a catalyst is lower than a predetermined overheat temperature, or (iii) a period in which the flow rate of refrigerant flowing to the exhaust gas recirculation cooler is lower than a predetermined flow rate and the temperature of the refrigerant is lower than a predetermined first temperature.

First claim

What is claimed is:

1. A control device for an internal combustion engine, the control device comprising:
an exhaust gas recirculation passage that connects an exhaust passage and an intake passage of an internal combustion engine to each other;
an exhaust gas recirculation cooler disposed in the exhaust gas recirculation passage, the exhaust gas recirculation cooler being configured to perform heat exchange between refrigerant and exhaust gas which flow through the exhaust gas recirculation cooler;
a bypass passage which is divided form from the exhaust gas recirculation passage, the bypass passage being configured to bypass the exhaust gas recirculation cooler;
a flow rate ratio adjusting mechanism configured to adjust a flow rate ratio between an amount of exhaust gas flowing to the exhaust gas recirculation cooler and an amount of exhaust gas flowing to the bypass passage;
an exhaust gas recirculation control mechanism configured to control execution and stopping of an exhaust gas recirculation operation for recirculating exhaust gas into a cylinder of the internal combustion engine through the exhaust gas recirculation passage; and
an electronic control unit configured to control the exhaust gas recirculation control mechanism and the flow rate ratio adjusting mechanism based on an operating state of the internal combustion engine,
wherein the electronic control unit is configured to adjust the flow rate ratio such that the amount of exhaust gas flowing to the exhaust gas recirculation cooler becomes zero during (i) a predetermined period from a point in time at which the exhaust gas recirculation operation shifts from stop to execution, (ii) a period in which fuel cut, in which fuel injection is stopped, is performed and a bed temperature of a catalyst disposed in the exhaust passage is lower than a predetermined overheat temperature, or (iii) a period in which a flow rate of refrigerant flowing to the exhaust gas recirculation cooler is lower than a predetermined flow rate and a temperature of the refrigerant is lower than a predetermined first temperature.

2. The control device according to claim 1 , wherein the electronic control unit is configured to adjust the flow rate ratio such that the amount of exhaust gas flowing to the bypass passage becomes zero when the bed temperature of the catalyst reaches the overheat temperature during a period in which the fuel cut is performed.

3. The control device according to claim 1 , wherein the electronic control unit is configured to adjust the flow rate ratio such that the amount of exhaust gas flowing to the exhaust gas recirculation cooler becomes zero during a period in which the temperature of the refrigerant is lower than a predetermined second temperature after the exhaust gas recirculation operation shifts from stop to execution.

4. The control device according to claim 1 , wherein:
the flow rate ratio adjusting mechanism is a flow rate ratio adjusting valve that is provided at an upstream side connecting portion at which the exhaust gas recirculation passage and the bypass passage are connected, and the upstream side connecting portion is closer to the exhaust passage than the exhaust gas recirculation cooler in the exhaust gas recirculation passage; and
the exhaust gas recirculation control mechanism is an exhaust gas recirculation control valve that is provided to be closer to the intake passage than the exhaust gas recirculation cooler in the exhaust gas recirculation passage, the exhaust gas recirculation control valve is closer to the intake passage than a downstream side connecting portion at which the exhaust gas recirculation passage and the bypass passage are connected, and the downstream side connecting portion is closer to the intake passage than the exhaust gas recirculation passage.

5. The control device according to claim 1 , wherein:
the flow rate ratio adjusting mechanism is a flow rate ratio adjusting valve that is provided at a downstream side connecting portion at which the exhaust gas recirculation passage and the bypass passage are connected, and the downstream side connecting portion is closer to the intake passage than the exhaust gas recirculation cooler in the exhaust gas recirculation passage; and
the exhaust gas recirculation control mechanism is an exhaust gas recirculation control valve that is provided so as to be closer to the intake passage than the flow rate ratio adjusting valve in the exhaust gas recirculation passage.

6. The control device according to claim 1 , wherein:
the flow rate ratio adjusting mechanism includes a first flow rate adjusting valve and a second flow rate adjusting valve, the first flow rate adjusting valve is provided so as to be closer to the exhaust passage than the exhaust gas recirculation cooler in the exhaust gas recirculation passage, the first flow rate adjusting valve is closer to the intake passage than an upstream side connecting portion, at which the exhaust gas recirculation passage and the bypass passage are connected, and which is closer to the exhaust passage than the exhaust gas recirculation cooler, and the second flow rate adjusting valve is provided in the bypass passage; and
the exhaust gas recirculation control mechanism includes the first flow rate adjusting valve and the second flow rate adjusting valve.

7. The control device according to claim 1 , wherein:
the flow rate ratio adjusting mechanism is configured to include a first flow rate adjusting valve and a second flow rate adjusting valve, the first flow rate adjusting valve is provided in the exhaust gas recirculation passage and the first flow rate adjusting valve is closer to the intake passage than a downstream side connecting portion, at which the exhaust gas recirculation passage and the bypass passage, and which is closer to the intake passage than the exhaust gas recirculation cooler, and the second flow rate adjusting valve is provided in the bypass passage; and
the exhaust gas recirculation control mechanism is configured to include the first flow rate adjusting valve and the second flow rate adjusting valve.

Assignees

• Toyota Motor Co Ltd

Inventors

• Morishima Akinori
• Ibuki Taku

Classifications

• F02M26/26

  characterised by details of the bypass valve · CPC title

• F02M26/71

  Multi-way valves · CPC title

• F02M26/28

  with liquid-cooled heat exchangers · CPC title

• F02M26/25

  with coolers having bypasses · CPC title

• F02M26/53

  using electric actuators, e.g. solenoids · CPC title