Low pressure exhaust gas recirculation apparatus

Patent metadata

Field	Value
Publication number	US-9709009-B2
Application number	US-84506710-A
Country	US
Kind code	B2
Filing date	Jul 28, 2010
Priority date	Jul 31, 2009
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A low pressure EGR regulating valve is driven by an electric actuator, and an output of the electric actuator is transmitted to an intake air throttle valve through a link device. An ECU executes a failure determination to determine presence of a failure in a case where a sensed opening degree, which is sensed with a low pressure EGR opening degree sensor, is other than an opening degree that corresponds to a maximum opening degree of the throttle valve limited by a mechanical stopper. The ECU executes the failure determination after the energization of the electric actuator is stopped in response to stopping of the engine.

First claim

What is claimed is:

1. A low pressure exhaust gas recirculation apparatus for an internal combustion engine that is communicated with an intake air passage, through which intake air is supplied to the internal combustion engine, and an exhaust passage, through which exhaust gas of the internal combustion engine is released to atmosphere, the low pressure exhaust gas recirculation apparatus comprising:
a low pressure exhaust gas recirculation (EGR) passage, which is configured to recirculate the exhaust gas as EGR gas from a low exhaust gas pressure area of the exhaust passage to a low negative intake air pressure generating area of the intake air passage;
a low pressure EGR regulating valve, which regulates an opening degree of the low pressure EGR passage to regulate a flow quantity of the EGR gas through the low pressure EGR passage;
a throttle valve, which is adapted to reduce an opening degree of one of the intake air passage and the exhaust passage to increase an EGR flow quantity of the EGR gas in the low pressure EGR passage;
an electric actuator, which drives the low pressure EGR regulating valve;
a link device, which converts an output of the electric actuator to drive the throttle valve;
a low pressure EGR opening degree sensor, which senses an opening degree of the low pressure EGR regulating valve;
a low pressure EGR valve return spring, which urges the low pressure EGR regulating valve in a closing direction thereof for closing the low pressure EGR passage upon stopping of energization of the electric actuator;
a mechanical stopper, which limits a maximum opening degree of the throttle valve; and
a failure sensing means for executing a failure determination to determine presence of a failure in a case where a sensed opening degree, which is sensed with the low pressure EGR opening degree sensor, is other than an opening degree that corresponds to a maximum opening degree of the throttle valve limited by the mechanical stopper, wherein the failure sensing means is activated after the energization of the electric actuator is stopped in response to stopping of the internal combustion engine.

2. The low pressure exhaust gas recirculation apparatus according to claim 1 , wherein the throttle valve is an intake air throttle valve, which is adapted to change the opening degree of the intake air passage at a location on an upstream side of a connection between the intake air passage and the low pressure EGR passage in a flow direction of the intake air.

3. The low pressure exhaust gas recirculation apparatus according to claim 1 , wherein the throttle valve is an exhaust throttle valve, which is adapted to change the opening degree of the exhaust passage at a location on a downstream side of a connection between the exhaust passage and the low pressure EGR passage in a flow direction of the exhaust gas.

4. The low pressure exhaust gas recirculation apparatus according to claim 2 , wherein the failure sensing means senses an intake air state of the intake air supplied to the internal combustion engine during a running state of the internal combustion engine and executes the failure determination based on the sensed intake air state.

5. The low pressure exhaust gas recirculation apparatus according to claim 1 , further comprising a throttle valve return spring, which applies an urging force against the throttle valve in an opening direction thereof for opening the one of the intake air passage and the exhaust passage.

6. The low pressure exhaust gas recirculation apparatus according to claim 1 , wherein:
the throttle valve is a butterfly valve, which regulates the opening degree of the one of the intake air passage and the exhaust passage by rotating a rotatable shaft of the butterfly valve, which is placed in an intermediate part of a valve plate of the butterfly valve; and
a fluid contact surface area of a downstream side valve plate portion of the valve plate, which is placed on a downstream side of the rotatable shaft, is larger than a fluid contact surface area of an upstream side valve plate portion of the valve plate, which is placed on an upstream side of the rotatable shaft, when the throttle valve is placed in a position, at which the opening degree of the one of the intake air passage and the exhaust passage is equal to or larger than a predetermined opening degree.

7. The low pressure exhaust gas recirculation apparatus according to claim 1 , wherein:
the low pressure EGR regulating valve includes an overturning means for overturning the low pressure EGR regulating valve from a first side of a full closed position of the low pressure EGR regulating valve, the first side including a full open position of the low pressure EGR regulating valve, to a second side of the full closed position, the second side of the full closed position opposite from the first side of the full closed position, after passing through the full closed position to open the low pressure EGR passage by a predetermined amount when the low pressure EGR regulating valve is driven from the one side of the full closed position to the other side of the full closed position; and
the low pressure EGR regulating valve is stopped at a position, at which the low pressure EGR passage is opened by the predetermined amount, through action of the low pressure EGR valve return spring and the overturn means upon the stopping of the internal combustion engine.

8. The low pressure exhaust gas recirculation apparatus according to claim 1 , wherein:
an inlet of the low pressure EGR passage is configured to be connected to the low exhaust gas pressure area of the exhaust passage located on a downstream side of an exhaust manifold; and
an outlet of the low pressure EGR passage is configured to be connected to the low negative intake air pressure generation area of the intake air passage located on an upstream side of an intake manifold.

9. The low pressure exhaust gas recirculation apparatus according claim 8 , wherein the inlet of the low pressure EGR passage is configured to be connected to the low exhaust gas pressure area of the exhaust passage located on a downstream side of a particulate filter in the exhaust passage.

10. The low pressure exhaust gas recirculation apparatus according to claim 1 , wherein:
an inlet of the low pressure EGR passage is configured to be connected to the low exhaust gas pressure area of the exhaust passage located on a downstream side of a high exhaust gas pressure area of the exhaust passage, at which an inlet of a high pressure EGR passage of a high pressure EGR apparatus is connected;
an outlet of the low pressure EGR passage is configured to be connected to the low negative intake air pressure generating area of the intake air passage located on an upstream side of a high negative intake air pressure generating area of the intake air passage, at which an outlet of the high pressure EGR passage is connected to recirculate the exhaust gas as EGR gas from the exhaust passage to the intake air passage;
an exhaust gas pressure in the low exhaust gas pressure area of the exhaust passage is smaller than that of the high exhaust gas pressure area of the exhaust passage when the internal combustion engine is running; and
a negative intake air pressure in the low negative intake air pressure generating area of the intake air passage is smaller than that of the high negative intake air pressure generating area of the intake air passage when the internal combustion engine is running.

11. A low pressure exhaust gas recirculation apparatus for an internal combustion engine that is communicated with an intake air passage, through which intake air is supplied to the internal combustion engine, and an exh

Assignees

• Miyazaki Shinsuke
• Furukawa Akira
• Shimane Osamu
• Sasaki Kazushi
• Takemoto Eiji
• Denso Corp

Inventors

• Miyazaki Shinsuke
• Furukawa Akira
• Shimane Osamu
• Sasaki Kazushi
• Takemoto Eiji

Classifications

• F02M26/25

  with coolers having bypasses · CPC title

• F02M26/49

  Detecting, diagnosing or indicating an abnormal function of the EGR system · CPC title

• F02M26/05

  High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor · CPC title

• F02M26/28

  with liquid-cooled heat exchangers · CPC title

• F02M26/51 Primary

  EGR valves combined with other devices, e.g. with intake valves or compressors (combined with intake air throttles F02M26/64) · CPC title