Exhaust gas recirculation system for engine

Patent metadata

Field	Value
Publication number	US-9388770-B2
Application number	US-201314052424-A
Country	US
Kind code	B2
Filing date	Oct 11, 2013
Priority date	Oct 22, 2012
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

Disclosed is an exhaust gas recirculation system for an engine ( 1 ), wherein at least a downstream sub-region of a region of an exhaust passage ( 33 ) upstream of a turbine wheel ( 52 ) is divided into two sub-passages (R 1 , R 2 ) by a partition wall ( 20 a, 30 a ) extending along an exhaust gas flow direction. A high-speed sub-passage (R 2 ) in the two sub-passages (R 1 , R 2 ) is equipped with an openable-closable exhaust variable valve ( 23 ). The exhaust variable valve ( 23 ) is configured to be controlled to open the high-speed sub-passage (R 2 ) when an engine speed is equal to or greater than a reference speed, and close the high-speed sub-passage (R 2 ) when the engine speed is less than the reference speed. An inlet ( 60 a ) of an EGR passage ( 60 ) on the side of the exhaust passage ( 33 ) is opened to the high-speed sub-passage (R 2 ) at a position downstream of the exhaust variable valve ( 23 ).

First claim

What is claimed is:

1. An exhaust gas recirculation system for an engine, in which an EGR passage is provided to communicate between an exhaust passage and an intake passage and allow a part of exhaust gas flowing through the exhaust passage to be recirculated to the intake passage therethrough, wherein characterized in that:
the exhaust passage is equipped with a turbine wheel of a turbocharger; and
at least a downstream sub-region of a region of the exhaust passage upstream of the turbine wheel is divided into two sub-passages by a partition wall extending along an exhaust gas flow direction,
wherein one of the two sub-passages is equipped with an openable-closable exhaust variable valve operated by a controller, the exhaust variable valve being configured to be controlled to open the one sub-passage when an engine speed is equal to or greater than a reference speed, and close the one sub-passage when the engine speed is less than the reference speed,
and wherein an inlet of the EGR passage on the side of the exhaust passage is opened to the one sub-passage at a position downstream of the exhaust variable valve.

2. The exhaust gas recirculation system as defined in claim 1 , wherein the EGR passage is arranged to extend from the inlet on the side of the exhaust passage to an outlet on the side of the intake passage, and equipped with an EGR cooler and an EGR valve in this order between the inlet and the outlet, wherein the EGR cooler and the EGR valve are provided at an uppermost position of the EGR passage.

3. The exhaust gas recirculation system as defined in claim 2 , wherein the region of the exhaust passage upstream of the turbine wheel has a sub-region passing through a cylinder head, and a sub-region passing through an exhaust manifold joined to the cylinder head, in this order from an upstream side, wherein:
the inlet of the EGR passage is provided at a position downstream of the sub-region passing through the exhaust manifold; and
at least of a part of a region of the EGR passage between the inlet and the EGR cooler is provided in respective walls of the exhaust manifold and the cylinder head.

4. The exhaust gas recirculation system as defined in claim 2 , wherein the region of the exhaust passage upstream of the turbine wheel has a sub-region passing through a cylinder head, and a sub-region passing through an exhaust manifold joined to the cylinder head, in this order from an upstream side, wherein:
the inlet of the EGR passage is provided at a position downstream of the sub-region passing through the exhaust manifold; and
at least of a part of a region of the EGR passage between the inlet and the EGR cooler is provided in respective walls of the exhaust manifold and the cylinder head.

5. The exhaust gas recirculation system as defined in claim 2 , wherein the region of the exhaust passage upstream of the turbine wheel has a sub-region passing through a cylinder head, and a sub-region passing through an exhaust manifold joined to the cylinder head, in this order from an upstream side, wherein:
the inlet of the EGR passage is provided at a position downstream of the sub-region passing through the exhaust manifold; and
at least of a part of a region of the EGR passage between the inlet and the EGR cooler is provided in respective walls of the exhaust manifold and the cylinder head.

6. The exhaust gas recirculation system as defined in claim 1 , wherein the EGR passage is arranged to extend from the inlet on the side of the exhaust passage to an outlet on the side of the intake passage, and equipped with an EGR cooler and an EGR valve in this order between the inlet and the outlet, wherein the EGR cooler and the EGR valve are provided at an uppermost position of the EGR passage.

7. The exhaust gas recirculation system as defined in claim 1 , wherein the EGR passage is arranged to extend from the inlet on the side of the exhaust passage to an outlet on the side of the intake passage, and equipped with an EGR cooler and an EGR valve in this order between the inlet and the outlet, wherein the EGR cooler and the EGR valve are provided at an uppermost position of the EGR passage.

8. An exhaust gas recirculation system for an engine, in which an EGR passage is provided to communicate between an exhaust passage and an intake passage and allow a part of exhaust gas flowing through the exhaust passage to be recirculated to the intake passage therethrough, wherein characterized in that:
the exhaust passage is equipped with a turbine wheel of a turbocharger; and
at least a downstream sub-region of a region of the exhaust passage upstream of the turbine wheel is divided into two sub-passages,
wherein one of the two sub-passages is equipped with an openable-closable exhaust variable valve operated by a controller, the exhaust variable valve being configured to be controlled to open the one sub-passage when an engine speed is equal to or greater than a reference speed, and close the one sub-passage when the engine speed is less than the reference speed, and the exhaust gas flow through an other one of the two sub-passages is not blocked by opening and closing of the exhaust variable valve,
and wherein an inlet of the EGR passage on the side of the exhaust passage is opened to the one sub-passage at a position downstream of the exhaust variable valve.

9. An exhaust gas recirculation system for an engine, in which an EGR passage is provided to communicate between an exhaust passage and an intake passage and allow a part of exhaust gas flowing through the exhaust passage to be recirculated to the intake passage therethrough, wherein characterized in that:
the exhaust passage is equipped with a turbine wheel of a turbocharger; and
at least a downstream sub-region of a region of the exhaust passage upstream of the turbine wheel is divided into a first sub-passage and a second sub-passage by a partition wall extending along an exhaust gas flow direction, the partition wall including a first, upstream end positioned at a first upstream end of the first sub-passage and a first upstream end of the second sub-passage, and a second, downstream end positioned at a second downstream end of the first sub-passage and a second downstream end of the second sub-passage,
wherein one of the two sub-passages is equipped with an openable-closable exhaust variable valve operated by a controller, the exhaust variable valve being configured to be controlled to open the first sub-passage when an engine speed is equal to or greater than a reference speed, and close the first sub-passage when the engine speed is less than the reference speed,
and wherein an inlet of the EGR passage on the side of the exhaust passage is opened to the first sub-passage at a position downstream of the exhaust variable valve.

Assignees

• Mazda Motor

Inventors

• Tsujita Shuhei
• Suekuni Einosuke
• Umemura Junji
• Nabetani Yuki

Classifications

• F02M26/44 Primary

  in which a main EGR passage is branched into multiple passages · CPC title

• F02B37/00

  Engines characterised by provision of pumps driven at least for part of the time by exhaust · CPC title

• F02D23/00

  Controlling engines characterised by their being supercharged · CPC title

• F02M25/0751 Primary

  Mechanical Engineering · mapped topic

• Y02T10/144

  Cross-Sectional Technologies · mapped topic