EGR control device

Patent metadata

Field	Value
Publication number	US-10408145-B2
Application number	US-201816009420-A
Country	US
Kind code	B2
Filing date	Jun 15, 2018
Priority date	Sep 26, 2017
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

An EGR control device includes: a drive unit, a basic opening degree deriving unit, a measurement unit, a memory unit, a correction opening degree deriving unit and a control unit. The drive unit varies an opening degree of an EGR valve. The basic opening degree deriving unit derives a basic EGR valve opening degree based on an operating condition of an engine. The measurement unit measures a temperature in the downstream side of a position of where EGR gas is recirculated in an intake passage. In the memory unit, information acquired in advance is stored. The information indicates a relationship between the opening degree and a temperature difference. The correction opening degree deriving unit derives a correction opening degree with reference to the information. The control unit controls the drive unit such that the opening degree of the EGR valve becomes a target EGR valve opening degree by correcting the basic EGR valve opening degree with the correction opening degree.

First claim

The invention claimed is:

1. An EGR control device comprising:
a drive unit configured to vary an opening degree of an EGR valve;
a basic opening degree deriving unit configured to derive a basic EGR valve opening degree of the EGR valve on a basis of an operating condition of an engine;
a measurement unit configured to measure a temperature in the downstream side of a position of where EGR gas is recirculated in an intake passage;
a memory unit in which information acquired in advance is stored, the information indicating a relationship between the opening degree of the EGR valve and a temperature difference between a temperature when the EGR valve is set to the opening degree and a temperature when the EGR valve is set to a reference opening degree;
a correction opening degree deriving unit configured to derive a correction opening degree of the EGR valve with reference to the information, based on the temperature difference between the temperature when the EGR valve is set to the reference opening degree and the temperature when the EGR valve is set to the basic EGR valve opening degree; and
a control unit configured to control the drive unit such that the opening degree of the EGR valve becomes a target EGR valve opening degree obtained by correcting the basic EGR valve opening degree with the correction opening degree.

2. The EGR control device according to claim 1 ,
wherein the correction opening degree deriving unit derives the correction opening degree of the EGR valve based on a differential temperature difference which is a difference between a first temperature difference between the temperature when the EGR valve is set to the basic EGR valve opening degree and the temperature when the EGR valve is set to the reference opening degree, and a second temperature difference between the temperature when the EGR valve is set to the basic EGR valve opening degree and the temperature when the EGR valve is set to the reference opening degree on the basis of the information stored in the memory unit.

3. The EGR control device according to claim 2 ,
wherein the information includes information indicating a slope of the temperature difference with respect to the opening degree of the EGR valve, in each of regions divided with the opening degree of the EGR valve, and
the correction opening degree deriving unit is configured to specify a region including the basic EGR valve opening degree among the regions, derive a virtual line including a value of the first temperature difference with respect to the basic EGR valve opening degree and having a slope in a region including the basic EGR valve opening degree, and derive the correction opening degree on the basis of the virtual line and the differential temperature difference.

4. The EGR control device according to claim 1 ,
wherein the correction opening degree deriving unit stores the derived correction opening degree in the memory unit.

5. The EGR control device according to claim 2 ,
wherein the correction opening degree deriving unit stores the derived correction opening degree in the memory unit.

6. The EGR control device according to claim 3 ,
wherein the correction opening degree deriving unit stores the derived correction opening degree in the memory unit.

Assignees

• Subaru Corp

Inventors

• Ushijima Hirooki

Classifications

• F02D2041/007

  by estimation · CPC title

• F02D2200/0414

  Air temperature · CPC title

• F02D41/0065

  Specific aspects of external EGR control (constructional details of EGR system F02M26/00) · CPC title

• F02D2041/0067

  Determining the EGR temperature · CPC title

• F02D41/0077 Primary

  Control of the EGR valve or actuator, e.g. duty cycle, closed loop control of position (EGR valve position sensor F02M26/48) · CPC title