Claims:We Claim
1. An exhaust gas recirculation flow path (10), said exhaust gas recirculation flow path (10) comprising:
an exhaust gas recirculation cooler (12);
an exhaust gas recirculation bypass flow path (14) coupled between an inlet (16) of said exhaust gas recirculation cooler (12) and an outlet (18) of said exhaust gas recirculation cooler (12);
an exhaust gas recirculation bypass valve (20) in flow communication with said exhaust gas recirculation bypass flow path (14) and adapted to control a flow of exhaust gas through said exhaust gas recirculation bypass flow path (14); characterized in that
a pressure sensor (22) in flow communication with said exhaust gas recirculation bypass flow path (14), said pressure sensor (22) adapted to sense a pressure of exhaust gas flowing through said exhaust gas recirculation bypass flow path (14).
2. A method for determining if an exhaust gas recirculation bypass valve (20) is functioning normally by an engine control unit, said method comprising:
determining if a plurality of engine operating conditions are satisfied, said plurality of engine operating conditions comprising whether the exhaust gas recirculation cooler bypass valve (20) is switched off, whether the engine is running, whether HFM/PFM errors are detected, whether the exhaust gas recirculation switch is in an on state, and whether exhaust gas recirculation flow deviation error is detected;
determining an actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) by means of a pressure sensor (22) upon satisfaction of the plurality of engine operating conditions; and
determining that the exhaust gas recirculation bypass valve (20) is functioning normally by an engine control unit if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) is greater than a minimum threshold pressure limit and lesser than a maximum threshold pressure limit.
3. A method for determining if an exhaust gas recirculation bypass valve (20) is faulty by an engine control unit, said method comprising:
determining if a plurality of engine operating conditions are satisfied, said plurality of engine operating conditions comprising whether an exhaust gas recirculation cooler bypass valve (20) is switched off, whether the engine is running, whether HFM/PFM errors are detected, whether the exhaust gas recirculation switch is in an on state, and whether exhaust gas recirculation flow deviation error is detected;
determining an actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) by means of a pressure sensor (22) upon satisfaction of the plurality of engine operating conditions; and
determining that the exhaust gas recirculation bypass valve (20) is faulty by the engine control unit if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) is one of lesser than a minimum threshold pressure limit and greater than a maximum threshold pressure limit.
4. The method in accordance with Claim 3 wherein determining that the exhaust gas recirculation bypass valve (20) is faulty by the engine control unit comprises determining that the exhaust gas recirculation bypass valve (20) is stuck in a closed position if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) is lesser than a minimum threshold pressure limit.
5. The method in accordance with Claim 3 wherein determining that the exhaust gas recirculation bypass valve (20) is faulty by the engine control unit comprises determining that the exhaust gas recirculation bypass valve (20) is stuck in an open position if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) is greater than a maximum threshold pressure limit.
6. An engine control unit, said engine control unit adapted to :
determine if a plurality of engine operating conditions are satisfied, said plurality of engine operating conditions comprising whether an exhaust gas recirculation cooler bypass valve (20) is switched off, whether the engine is running, whether HFM/PFM errors are detected, whether the exhaust gas recirculation switch is in an on state, and whether exhaust gas recirculation flow deviation error is detected;
determine an actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) by means of a pressure sensor (22) upon satisfaction of the plurality of engine operating conditions; and
determine that the exhaust gas recirculation bypass valve (20) is functioning normally if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) is greater than a minimum threshold pressure limit and lesser than a maximum threshold pressure limit.
7. An engine control unit, said engine control unit adapted to :
determine if a plurality of engine operating conditions are satisfied, said plurality of engine operating conditions comprising whether an exhaust gas recirculation cooler bypass valve (20) is switched off, whether the engine is running, whether HFM/PFM errors are detected, whether the exhaust gas recirculation switch is in an on state, and whether exhaust gas recirculation flow deviation error is detected;
determine an actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) by means of a pressure sensor (22) upon satisfaction of the plurality of engine operating conditions; and
determine that the exhaust gas recirculation bypass valve (20) is faulty if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve (20) is one of lesser than a minimum threshold pressure limit and greater than a maximum threshold pressure limit.
, Description:Field of the invention
[0001] This invention relates to an exhaust gas recirculation bypass flow path and more particularly to a pressure sensor in flow communication with the exhaust gas recirculation bypass flow path.

Background of the invention
[0002] KR 19980047835 U describes an exhaust gas recirculation valve control device in communication with the intake manifold and the exhaust gas recirculation device exhaust gas recirculation exhaust manifold. The exhaust gas is discharged through the exhaust pressure sensor that detects the pressure of the vaporized gas discharged from the engine. The exhaust pressure is compared to the reference value set when the exhaust pressure is higher than the reference value. A control signal is output to an ECU and driven by the control of the intake manifold in communication with the vacuum valve and the exhaust gas in association with the vacuum valve to bypass the intake manifold by configuring the EGR valve is higher than the exhaust pressure is a reference pressure through vacuum valve by an EGR valve in proportion to engine output shown is able to control the exhaust gas recirculation amount.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic diagram of an exhaust gas recirculation flow path.

Detailed description of the invention
[0004] An exhaust gas recirculation flow path 10 is described. The exhaust gas recirculation flow path 10 comprises an exhaust gas recirculation cooler 12. An exhaust gas recirculation bypass flow path 14 is coupled between an inlet 16 of the exhaust gas recirculation cooler 12 and an outlet 18 of the exhaust gas recirculation cooler 12. An exhaust gas recirculation bypass valve 20 coupled in flow communication with the exhaust gas recirculation bypass flow path 14 and is adapted to control a flow of exhaust gas through the exhaust gas recirculation bypass flow path 14. A pressure sensor 22 is coupled in flow communication with the exhaust gas recirculation bypass flow path 14, the pressure sensor 22 adapted to sense a pressure of exhaust gas flowing through the exhaust gas recirculation bypass flow path 14.
[0005] In addition, a method for determining if an exhaust gas recirculation bypass valve 20 is functioning normally by an engine control unit is described. The method comprises determining if a plurality of engine operating conditions are satisfied, the plurality of engine operating conditions comprising whether the exhaust gas recirculation cooler bypass valve 20 is switched off, whether the engine is running, whether HFM/PFM errors are detected, whether the exhaust gas recirculation switch is in an on state, and whether exhaust gas recirculation flow deviation error is detected. The method further comprises determining an actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 by means of a pressure sensor 22 upon satisfaction of the plurality of engine operating conditions. In addition, the method comprises determining that the exhaust gas recirculation bypass valve 20 is functioning normally by an engine control unit if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 is greater than a minimum threshold pressure limit and lesser than a maximum threshold pressure limit.
[0006] Moreover, an engine control unit is described. The engine control unit is adapted to determine if a plurality of engine operating conditions are satisfied, the plurality of engine operating conditions comprising whether an exhaust gas recirculation cooler bypass valve 20 is switched off, whether the engine is running, whether HFM/PFM errors are detected, whether the exhaust gas recirculation switch is in an on state, and whether exhaust gas recirculation flow deviation error is detected. The engine control unit further determines an actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 by means of a pressure sensor 22 upon satisfaction of the plurality of engine operating conditions. In addition, the engine control unit determines that the exhaust gas recirculation bypass valve 20 is functioning normally if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 is greater than a minimum threshold pressure limit and lesser than a maximum threshold pressure limit.

[0007] The exhaust gas recirculation flow path 10 comprises an exhaust gas recirculation cooler 12. The exhaust gas recirculation cooler 12 comprises an inlet 16 adapted to receive exhaust gas from an engine. The exhaust gas that is received from the engine is cooled in the exhaust gas recirculation cooler 12 and then delivered to the outlet 18 of the exhaust gas recirculation cooler 12. The exhaust gas recirculation flow path 10 comprises an exhaust gas recirculation bypass flow path 14 that is coupled between the inlet 16 of the exhaust gas recirculation cooler 12 and the outlet 18 of the exhaust gas recirculation cooler 12. The exhaust gas recirculation bypass flow path 14 is adapted to channel exhaust gas at an elevated temperature that is not required to be cooled by the exhaust gas recirculation cooler 12 to the outlet 18 of the exhaust gas recirculation cooler 12, thereby bypassing the exhaust gas recirculation cooler 18. An exhaust gas recirculation bypass valve 20 is coupled in flow communication with the exhaust gas recirculation bypass flow path 14. More specifically, the exhaust gas recirculation bypass valve 20 is adapted to control a flow of exhaust gas through the exhaust gas recirculation bypass flow path 14.
[0008] Therefore, if the mass flow rate of exhaust gas through the exhaust gas recirculation cooler 12 is required to be decreased to facilitate increasing the temperature of exhaust gas, the exhaust gas recirculation bypass valve 20 is opened to facilitate channeling exhaust gas through the exhaust gas recirculation bypass flow path 14. The flow of exhaust gas through the exhaust gas recirculation bypass flow path 14 causes the temperature of the exhaust gas at the outlet 18 of the exhaust gas recirculation cooler 18 to increase. If the exhaust gas recirculation bypass valve 20 is closed, the entire exhaust gas that is released from the engine is channeled to the exhaust gas recirculation cooler 12 where it is substantially cooled and subsequently released to the outlet 18 of the of the exhaust gas recirculation cooler 12. Therefore, the temperature of the exhaust gas at the outlet 18 of the exhaust gas recirculation cooler 12 decreases more than if the exhaust gas recirculation bypass valve 20 is open.
[0009] A pressure sensor 22 is coupled in flow communication with the exhaust gas recirculation bypass flow path 14. In an exemplary embodiment, the pressure sensor 22 may be any type of pressure sensor 22 that senses the pressure of the exhaust gas flowing through the exhaust gas recirculation bypass flow path 14. The pressure sensor 22 comprises a sensing element that is positioned within the exhaust gas recirculation bypass flow path 14 and senses a pressure of exhaust gas flowing through the exhaust gas recirculation bypass flow path 14. When the exhaust gas recirculation bypass valve 20 is closed, the pressure sensor 22 senses that the pressure of the exhaust gas within the exhaust gas recirculation bypass flow path is low. When the exhaust gas recirculation bypass valve 20 is opened, the pressure sensor 22 senses that the pressure of the exhaust gas within the exhaust gas recirculation bypass flow path 14 is high as the exhaust gas from the engine flows through the exhaust gas recirculation bypass flow path 14. An engine control unit is in electronic communication with the pressure sensor and is adapted to determine if the exhaust gas recirculation bypass valve 20 is functioning normally or is stuck in an open / closed position as will be explained in further detail below.
[0010] A working of the exhaust gas recirculation bypass flow path 14 is explained as an example. The engine control unit determines if a plurality of engine operating conditions are satisfied before a signal from the pressure sensor 22 can be received. The plurality of engine operating conditions comprises whether the exhaust gas recirculation cooler bypass valve 20 is switched off, whether the engine is running, whether HFM/PFM errors are detected, whether the exhaust gas recirculation switch is in an on state, and whether exhaust gas recirculation flow deviation error is detected. Once the engine control unit determines that the above conditions are met, the engine control unit determines an actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 by means of the pressure sensor 22.
[0011] A user can set a minimum threshold pressure limit. If the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 as determined by the pressure sensor 22 is lesser than the minimum threshold pressure limit, it may be inferred by the engine control unit that the exhaust gas recirculation bypass valve 20 is closed.
[0012] The user can set a maximum threshold pressure limit. If the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 as determined by the pressure sensor 22 is greater than the maximum threshold pressure limit, it may be inferred that the exhaust gas recirculation bypass valve 20 is open by the engine control unit. The engine control unit determines that the exhaust gas recirculation bypass valve 20 is functioning normally if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 is greater than the minimum threshold pressure limit and lesser than the maximum threshold pressure limit. The engine control unit determines that the exhaust gas recirculation bypass valve 20 is faulty if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 is lesser than the minimum threshold pressure limit. In addition, the engine control unit determines that the exhaust gas recirculation bypass valve 20 is faulty if the actual value of pressure of exhaust gas flowing through the exhaust gas recirculation bypass valve 20 is greater than the maximum threshold pressure limit.
[0013] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to leverage and dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.