Control device of internal-combustion engine

Patent metadata

Field	Value
Publication number	US-10436154-B2
Application number	US-201815912572-A
Country	US
Kind code	B2
Filing date	Mar 6, 2018
Priority date	Mar 21, 2017
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

In a control device of an internal-combustion engine according to the disclosure, an intake throttle valve ( 25 ) for adjusting an EGR valve differential pressure (ΔPEGR) is provided, an EGR valve upstream pressure (PEGR 0 ) is estimated by using a target fresh air amount (GAIRCMD) (step 6 ), a target differential pressure (ΔPEGRCMD) is set to a smaller value as the target fresh air amount (GAIRCMD) becomes smaller (FIG. 5 ), and a difference between the EGR valve upstream pressure (PEGR 0 ) and the target differential pressure (ΔPEGRCMD) is set as a target valve downstream pressure (P 1 CMD) (step 7 ). By using the target fresh air amount (GAIRCMD), the EGR valve upstream pressure (PEGR 0 ), and the target valve downstream pressure (P 1 CMD), the target EGR valve opening degree (LEGRCMD) is set (step 23 ), and an EGR valve ( 43 ) is controlled based on the target EGR valve opening degree (step 24 ).

First claim

What is claimed is:

1. A control device of an internal-combustion engine for controlling an EGR amount which is an amount of an exhaust gas recirculated from an exhaust passage to an intake passage through an EGR passage, comprising:
an EGR valve which is provided in the EGR passage to adjust the EGR amount;
a throttle valve which is provided at one of an upstream side of the intake passage in relation to a connection portion between the intake passage and the EGR passage and a downstream side of the exhaust passage in relation to a connection portion between the exhaust passage and the EGR passage to adjust a differential pressure between an upstream pressure and a downstream pressure of the EGR valve;
a target EGR amount setting unit which sets a target EGR amount which is a target of the EGR amount;
a flow rate parameter acquiring unit which acquires a flow rate parameter representing a flow rate of fresh air and/or an exhaust gas corresponding to a load of the internal-combustion engine;
an opposite throttle valve side pressure estimation unit which estimates an opposite throttle valve side pressure which is a pressure at the opposite side to the throttle valve among an upstream side and a downstream side of the EGR valve using the acquired flow rate parameter;
a target differential pressure setting unit which sets a target differential pressure which is a target of the differential pressure to a smaller value as the flow rate indicated by the flow rate parameter becomes smaller;
a target throttle valve side pressure setting unit which sets a target throttle valve side pressure which is a target of a throttle valve side pressure on the side of the throttle valve among the upstream side and the downstream side of the EGR valve based on the target differential pressure and the opposite throttle valve side pressure;
a target EGR valve opening degree setting unit which sets a target EGR valve opening degree which is a target of an opening degree of the EGR valve by using the target EGR amount, the opposite throttle valve side pressure, and the target throttle valve side pressure; and
an EGR valve control unit which controls the EGR valve based on the target EGR valve opening degree.

2. The control device of the internal-combustion engine according to claim 1 ,
wherein the target differential pressure setting unit sets the target differential pressure so that the target differential pressure is not smaller than a predetermined lower-limit value.

3. The control device of the internal-combustion engine according to claim 2 ,
wherein the throttle valve is an intake throttle valve which is provided at an upstream side of the intake passage in relation to the connection portion between the intake passage and the EGR passage and generates a negative pressure at the downstream side of the EGR valve by a throttling to adjust the differential pressure,
wherein the throttle valve side pressure is the downstream pressure of the EGR valve,
wherein the opposite throttle valve side pressure is the upstream pressure of the EGR valve, and
wherein the flow rate parameter is a target fresh air amount set as a target value of a fresh air amount.

4. The control device of the internal-combustion engine according to claim 3 , further comprising:
an intake throttle valve upstream pressure estimation unit which estimates an upstream pressure of the intake throttle valve by using the target fresh air amount;
a target intake throttle valve opening degree setting unit which sets a target intake throttle valve opening degree which is a target of an opening degree of the intake throttle valve by using the target fresh air amount, the upstream pressure of the intake throttle valve, and the downstream pressure of the EGR valve; and
an intake throttle valve control unit which controls the intake throttle valve based on the target intake throttle valve opening degree.

5. The control device of the internal-combustion engine according to claim 2 ,
wherein the throttle valve is an exhaust throttle valve which is provided at a downstream side of the exhaust passage in relation to the connection portion between the exhaust passage and the EGR passage and increases the upstream pressure of the EGR valve by a throttling to adjust the differential pressure,
wherein the throttle valve side pressure is the upstream pressure of the EGR valve,
wherein the opposite throttle valve side pressure is the downstream pressure of the EGR valve, and
wherein the flow rate parameter is a target fresh air amount set as a target value of a fresh air amount.

6. The control device of the internal-combustion engine according to claim 5 , further comprising:
an exhaust throttle valve downstream pressure estimation unit which estimates a downstream pressure of the exhaust throttle valve by using the target fresh air amount;
a target exhaust throttle valve opening degree setting unit which sets a target exhaust throttle valve opening degree which is a target of an opening degree of the exhaust throttle valve by using the target fresh air amount, the downstream pressure of the exhaust throttle valve, and the upstream pressure of the EGR valve; and
an exhaust throttle valve control unit which controls the exhaust throttle valve based on the target exhaust throttle valve opening degree.

7. The control device of the internal-combustion engine according to claim 1 ,
wherein the throttle valve is an intake throttle valve which is provided at an upstream side of the intake passage in relation to the connection portion between the intake passage and the EGR passage and generates a negative pressure at the downstream side of the EGR valve by a throttling to adjust the differential pressure,
wherein the throttle valve side pressure is the downstream pressure of the EGR valve,
wherein the opposite throttle valve side pressure is the upstream pressure of the EGR valve, and
wherein the flow rate parameter is a target fresh air amount set as a target value of a fresh air amount.

8. The control device of the internal-combustion engine according to claim 7 , further comprising:
an intake throttle valve upstream pressure estimation unit which estimates an upstream pressure of the intake throttle valve by using the target fresh air amount;
a target intake throttle valve opening degree setting unit which sets a target intake throttle valve opening degree which is a target of an opening degree of the intake throttle valve by using the target fresh air amount, the upstream pressure of the intake throttle valve, and the downstream pressure of the EGR valve; and
an intake throttle valve control unit which controls the intake throttle valve based on the target intake throttle valve opening degree.

9. The control device of the internal-combustion engine according to claim 1 ,
wherein the throttle valve is an exhaust throttle valve which is provided at a downstream side of the exhaust passage in relation to the connection portion between the exhaust passage and the EGR passage and increases the upstream pressure of the EGR valve by a throttling to adjust the differential pressure,
wherein the throttle valve side pressure is the upstream pressure of the EGR valve,
wherein the opposite throttle valve side pressure is the downstream pressure of the EGR valve, and
wherein the flow rate parameter is a target fresh air amount set as a target value of a fresh air amount.

10. The control device of the internal-combustion engine according to claim 9 , further comprising:
an exhaust throttle valve downstream pressure estimation unit which estimates a downstream pressure of the exhaust throttle valve by using the target fresh air amount;
a target exhaust throttle valve

Assignees

• Honda Motor Co Ltd

Inventors

• Ueno Masaki
• Kimura Noritaka
• Ihara Kosuke
• Katori Yuto
• Uto Hajime
• Yamada Yosuke
• Hidaka Masashi

Classifications

• F02D41/0077

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

• F02D41/1446

  the characteristics being exhaust temperatures · CPC title

• F02D41/1448

  the characteristics being an exhaust gas pressure · CPC title

• F02D2041/0017

  by simultaneous control of throttle and exhaust gas recirculation · CPC title

• F02M26/47

  the characteristics being temperatures, pressures or flow rates · CPC title