KR102765635B1 - Spring Slide Abrasion Prevention type 3 Way EGR Valve Unit EGR(and Exhaust Gas Recirculation System thereby - Google Patents

Abstract

The spring-type wear prevention type 3-way EGR valve unit (1) applied to the EGR system (200) of the present invention opens and closes the EGR flow port (5) with the EGR valve (40) of the EGR valve shaft (41) fixed to the segment gear (30) by the driving force of the motor and reducer built into the valve housing (3), opens and closes the air flow port (7) with the intake valve (80) of the intake valve shaft (81) fixed to the rotation arm (60) together with the ball bearing (70) in contact with the profile (30A) rotated by the segment gear (30), and returns the EGR valve (40) to the default position when restored after being tensioned in the rotational direction of the segment gear (30). And by including an intake return tension spring (90) that returns the intake valve (80) to the default position when restored after tensioning in the rotational direction of the rotation arm (60), the valve operation failure (STUCK) due to internal wear foreign substances is eliminated by removing the spring sliding part inside the valve housing, and in particular, by eliminating the torsion spring mounting space in the internal space of the valve housing, the degree of freedom in the layout of valve parts is greatly improved, and the axial length of the EGR valve and intake valve is reduced, thereby reducing the size of the finished product.

Description

{Spring Slide Abrasion Prevention type 3 Way EGR Valve Unit EGR (and Exhaust Gas Recirculation System thereby}

The present invention relates to a three-way EGR valve unit, and more particularly, to an EGR system to which a three-way EGR valve unit is applied that does not form a spring sliding part with the inside of the valve by a tensile return spring.

Generally, a 3-way EGR valve unit applied to a vehicle's EGR (Exhaust Gas Recirculation) system supplies a portion of the exhaust gas as EGR gas to be mixed with the intake (i.e., fresh air) of the intake in the engine's combustion chamber. In this case, the EGR system contributes to improved performance and fuel efficiency along with increased engine output by supplying EGR gas in addition to increasing the air supply amount by compressing the intake air.

For example, the above-described 3-way EGR valve unit is composed of a motor, a reduction gear, a cam, a rotation arm, an intake valve, an EGR return spring (i.e., for the EGR valve), and an intake return spring (i.e., for the intake valve) linked to the EGR valve. In this case, the EGR valve opens and closes a passage in the EGR flow port of the valve housing, and the intake valve opens and closes a passage in the air flow port of the valve housing, respectively.

Through this, the above-mentioned 3-way EGR valve unit uses a motor and a reduction gear to rotate the EGR valve during the EGR valve opening operation (i.e., OPEN operation), and according to the rotation, a cam structure mounted on the EGR valve gear pushes the bearing of the rotation arm to rotate (i.e., CLOSE) the intake valve, and during the EGR valve closing operation (i.e., CLOSE operation) in which the valve returns to the default position (CLOSE) after valve operation (OPEN), the EGR valve is returned by the motor and reduction gear, and the intake valve is returned (i.e., OPEN operation) by the intake return spring.

In addition, the EGR return spring and the intake return spring operate as limp home operating parts in the event of a motor failure, so that the EGR return spring is responsible for returning the EGR valve to the default position (i.e., CLOSE) and the intake return spring is responsible for returning the intake valve to the default position (i.e., OPEN), respectively.

Therefore, the above 3-way EGR valve unit can solve the problem of the EGR valve and intake valve not returning to the default position through the return spring even in the event of a motor failure, and especially, can additionally perform the limp-home function in the event of an uncontrollable state due to a motor failure, etc. during product operation.

Japanese registered patent JP 5086338 B (2012.09.14)

However, the above return spring is a torsion spring type and has the characteristic of always sliding against the spring guide (inside the spring) during rotational motion, which causes a problem in that it acts as a load and has a negative effect.

For example, referring to Fig. 5, which illustrates the adverse effect of friction between a valve housing and a spring when using a torsion return spring, in the case of the shaft boss (95) of the valve housing (3), the return spring inevitably causes adverse effects due to internal wear foreign substances as the spring friction portion wears during long-term operation, and in severe cases, the internal wear foreign substances may cause problems that lead to valve malfunction (STUCK).

Accordingly, taking the above points into consideration, the present invention aims to provide a spring friction wear prevention type 3-way EGR valve unit and EGR system in which a tension return spring is applied to the outside of an EGR valve and an intake valve, thereby eliminating the spring friction part inside the valve housing and thereby achieving stable valve operation without valve operation malfunction (STUCK) due to internal wear foreign substances, and in particular, the freedom of layout for valve parts is greatly improved by eliminating the torsion spring mounting space in the internal space of the valve housing, and the axial length of the EGR valve and intake valve is reduced, thereby reducing the size of the finished product.

In order to achieve the above object, the three-way EGR valve unit of the present invention is characterized by including: a valve housing having an EGR flow port and an air flow port; an EGR valve coupled to an EGR valve shaft having a segment gear fixed thereon, which is rotated by the driving force of a motor and a reducer, and which opens and closes the EGR flow port by counterclockwise rotation of the segment gear; an intake valve coupled to an intake valve shaft having a rotation arm fixed thereon together with a ball bearing in contact with a profile rotated by the segment gear, and which opens and closes the air flow port according to the rotation direction of the rotation arm; an EGR return tension spring tensioned by the segment gear when the EGR valve is opened by counterclockwise rotation of the segment gear; and an intake return tension spring tensioned by the rotation arm when the intake valve is closed by clockwise rotation of the rotation arm.

In a preferred embodiment, the EGR return tension spring, when restored after being tensioned by the segment gear, rotates the segment gear clockwise to return the EGR valve to the default position.

In a preferred embodiment, the EGR return tension spring is positioned on an upper surface of the segment gear in the segment gear receiving space of the valve housing, has one end fixed by a valve housing upper hook having a protrusion structure formed on the valve housing, and has the opposite end fixed by a segment gear hook having a protrusion structure formed on the upper surface of the segment gear, and the segment gear hook is positioned in a lower area of the segment gear.

In a preferred embodiment, the intake return tension spring, when restored after being tensioned by the rotation arm, rotates the rotation arm counterclockwise to return the intake valve to the default position.

In a preferred embodiment, the intake return tension spring is positioned on an upper surface of the rotation arm in the rotation arm receiving space of the valve housing, has one end fixed by a valve housing lower hook having a protrusion structure formed on the valve housing, and has the opposite end fixed by a rotation arm hook having a protrusion structure formed on an upper surface of the rotation arm, and the rotation arm hook is positioned in a lower region of the rotation arm.

And to achieve the above object, the EGR system of the present invention comprises a three-way EGR valve unit comprising an EGR valve of an EGR valve shaft fixed to a segment gear which is rotated by the driving force of a motor and a reducer built into a valve housing, which opens and closes an EGR flow port, and an intake valve of an intake valve shaft fixed to a rotation arm together with a ball bearing which is in contact with a profile which is rotated by the segment gear, which opens and closes an air flow port, and an EGR return tension spring which returns the EGR valve to a default position when tensioned and then restored in accordance with the rotational direction of the segment gear; and an intake return tension spring which returns the intake valve to a default position when tensioned and then restored in accordance with the rotational direction of the rotation arm, and is characterized in that when the valve of the three-way EGR valve unit is opened, the EGR gas flow rate from the EGR flow rate port and the air flow rate from the air flow rate port are sent to an engine of an engine system.

In a preferred embodiment, the EGR flow port and the air flow port have an acute angled layout.

As a preferred embodiment, the EGR valve is a low pressure EGR valve type that extracts some of the exhaust gas flowing through the exhaust pipe of the engine system at a position after the turbocharger and supplies it as EGR gas.

The spring wet wear prevention type 3-way EGR valve unit applied to the EGR system of the present invention implements the following functions and effects.

First, since a tension return spring with no spring movement structure source is used in comparison with a torsion spring having a spring movement part for returning to the default position, stable valve operation is achieved without valve operation malfunction (STUCK) due to internal wear foreign substances. Second, since the difficulty of assembling parts is reduced compared to the internal assembly structure of the existing torsion spring, assembly man-hours are improved. Third, since the spring space is eliminated inside the valve, the degree of freedom in the layout of valve parts is greatly improved. Fourth, since the spring space is eliminated inside the valve, the axial length of the EGR valve and intake valve is reduced, which enables the manufacture of a more compact 3-way EGR valve unit by reducing the size of the finished product.

FIG. 1 is a configuration diagram of a spring wet wear prevention type 3-way EGR valve unit according to the present invention, FIG. 2 is a layout example of a spring wet wear prevention type tensile return spring according to the present invention, FIG. 3 is an example of an EGR system to which a spring wet wear prevention type 3-way EGR valve unit according to the present invention is applied, FIG. 4 is an operating state of a 3-way EGR valve unit in an EGR system according to the present invention, and FIG. 5 is a state exemplifying a wet wear side effect between a valve housing and a spring when a torsion return spring, which is a conventional technology, is used.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached exemplary drawings. These embodiments are provided as examples, and since those skilled in the art can implement the present invention in various different forms, it is not limited to the embodiments described herein.

Referring to Fig. 1, a three-way EGR valve unit (1) has an EGR valve (40) that opens and closes an EGR flow port (5) of a valve housing (3) and an intake valve (80) that opens and closes an air flow port (7), and a tension return spring (50, 90) applied thereto. In this case, the three-way EGR valve unit (1) is an LP (Low Pressure) EGR throttle valve in which a low-pressure type EGR valve (40) is an integrated valve of an intake valve (80) that is an air flow control valve, thereby controlling the flow rate for improving fuel efficiency by recirculating exhaust gas to a combustion chamber.

For example, the valve housing (3) forms the overall shape and size of the three-way EGR valve unit (1), and is formed with a layout in which the EGR flow port (5) and the air flow port (7) are arranged within an acute angle of 90° with respect to each other, and the EGR flow port (5) supplies a portion of the exhaust gas as EGR gas, and the air flow port (7) supplies external air (i.e., atmosphere) as fresh air.

Specifically, the above-described three-way EGR valve unit (1) is configured as a driving part including a segment gear (30) equipped with a profile (30A), a rotation arm (60), and a ball bearing (70) that rotates by the driving force of a motor and a reducer assembled in a valve housing (3), and an EGR valve (40) positioned at an EGR flow port (5) to control EGR flow rate and an intake valve (80) positioned at an air flow port (7) to control air flow rate are configured as a valve part. In this case, the motor is a DC motor driven by PID (Proportional Integral Differential) control by an ECU (Electronic Control Unit) (e.g., EGR controller) to generate power to open and close (i.e., open and close) the EGR valve (40) and the intake valve (80), and the reducer is configured as a two-stage gear with small and large diameters to change the rotational speed and torque (i.e., motor driving force) of the motor.

For example, the segment gear (30) is connected to the EGR valve (40) via the EGR valve shaft and is fixed to a large-diameter gear among the second gears of the reducer and rotates together, and the profile (30A) is inserted into the segment gear (30) and operates together to operate the ball bearing (70). The rotation arm (60) is formed in a disc shape and is connected to the intake valve (80) via the intake valve shaft, and the ball bearing (70) is combined with a bearing rod fixed to the intake valve shaft and moves in contact with the profile (30A) so that the rotation arm (60) follows the rotation of the segment gear (30).

In particular, the segment gear (30) is positioned in the segment gear receiving space of the valve housing (3), and the segment gear receiving space forms an axial boss (95) (see FIG. 5) through which the EGR valve shaft (41) passes. And the rotation arm (60) is positioned in the rotation arm receiving space of the valve housing (3), and the rotation arm receiving space forms an axial boss (95) (see FIG. 5) through which the intake valve shaft (81) passes. In this case, the distance between the segment gear receiving space and the rotation arm receiving space with respect to the axial boss (95) (see FIG. 5) is defined as the valve shaft-to-axis distance (L).

Therefore, the above segment gear (30) and the above profile (30A) directly operate the EGR valve (40) using the motor/reducer as a power source, and the above rotation arm (60) and the above ball bearing (70) directly operate the intake valve (80).

For example, in the valve section, the EGR valve (40) is coupled with the segment gear (30) and the EGR valve shaft (41) that fixes the profile (30A) and is positioned at the EGR flow port (5), and the EGR flow rate is controlled by opening the passage of the EGR flow port (5) according to the rotation direction and degree of the segment gear (30). The intake valve (80) is positioned at the air flow port (7) through the intake valve shaft (81) that fixes the rotation arm (60) and the ball bearing (70), and the air flow rate is controlled by closing the passage of the air flow port (7) according to the rotation direction and degree of the rotation of the rotation arm (60).

In addition, the above-mentioned three-way EGR valve unit (1) applies a return spring (50, 90) to a limp home operating part, and the return spring (50, 90) is composed of an EGR return tension spring (50) for the EGR valve (40) and an intake return tension spring (90) for the intake valve (80).

For example, the EGR return tension spring (50) is installed on the upper surface of the segment gear (30) in the lower region of the segment gear so that it is tensioned by the segment gear (30) during the EGR valve opening operation (i.e., OPEN operation) and then restored during the EGR valve closing operation (i.e., CLOSE operation), and the intake return tension spring (90) is installed on the upper surface of the rotation arm (60) in the lower region of the rotation arm so that it is tensioned by the rotation arm (60) that rotates together with the ball bearing (70) during the EGR valve opening operation (i.e., OPEN operation) and then restored during the EGR valve closing operation (i.e., CLOSE operation).

In particular, the EGR return tension spring (50) performs an EGR valve closing operation (i.e., a CLOSE operation) by providing an elastic restoring force that returns the EGR valve (40) to the default position in a motor failure state, and the intake return tension spring (90) is linked to the EGR valve closing operation (i.e., a CLOSE operation) by providing an elastic restoring force that returns the intake valve (80) to the default position in a motor normal and failure state.

Therefore, the EGR return tension spring (50) and the intake return tension spring (90) are tension spring types in which one end is pulled while both ends are fixed.

From this, the space of the valve housing (3) where the lower part of the segment gear (30) and the lower part of the rotation arm (60) are located in the three-way EGR valve unit (1) can be reduced compared to the existing EGR torsion spring and intake torsion spring mounting structure. This is because the space of the valve housing (3) must be formed with a length (i.e., size) that can accommodate the sizes of the existing EGR torsion spring and intake torsion spring.

For example, when the space of the valve housing (3) is defined as the EGR shaft hub space length (La) and the intake shaft hub space length (Lb), the EGR shaft hub space length (La) is set to accommodate only the shaft hub structure formed at the lower portion of the segment gear (30), thereby being able to be shortened further by excluding the EGR torsion spring size that was previously considered, and the intake shaft hub space length (Lb) is set to accommodate only the shaft hub structure formed at the lower portion of the rotation arm (60), thereby being able to be shortened further by excluding the intake torsion spring size that was previously considered.

Therefore, the valve housing (3) can also shorten the valve axis distance (L) between the EGR valve shaft (41) and the intake valve shaft (81) by the amount of reduction in the EGR shaft hub space length (La) and the intake shaft hub space length (Lb), and this reduction in the valve axis distance (L) acts to reduce the valve housing size (Size) by that amount.

As a result, the above three-way EGR valve unit (1) can be manufactured in a more compact size while maintaining the mounting gap between the EGR valve (40) and the intake valve (80) with a shortened valve shaft distance (L).

Referring to FIG. 2, the fixing structure of the EGR return tension spring (50) and the intake return tension spring (90) is exemplified.

For example, in the fixed structure of the EGR return tension spring (50), the EGR return tension spring (50) is fixed at one end of both ends to the valve housing upper hook (51) of the valve housing (3), and the opposite end is fixed to the segment gear hook (52) of the segment gear (30), thereby being installed at the upper surface of the segment gear (30) in the lower region of the segment gear. In this case, the segment gear hook (52) is located at the lower region of the segment gear (30).

For example, in the fixed structure of the above-described intake return tension spring (90), one end of the intake return tension spring (90) is fixed to the valve housing lower hook (91) of the valve housing (3) and the opposite end is fixed to the rotation arm hook (92) of the rotation arm (60), thereby being installed in the lower region of the rotation arm to the upper surface of the rotation arm (60). In this case, the rotation arm hook (92) is located in the lower region of the rotation arm (60).

In particular, each of the valve housing upper hook (51), the segment gear hook (52), the valve housing lower hook (91) and the rotation arm hook (92) is formed with a protrusion structure.

Therefore, the EGR return tension spring (50) enables a limp home operation to return the EGR valve (40) to the default position (CLOSE) even in a motor failure state when the EGR valve is closed (i.e., CLOSE operation) to return to the default position (CLOSE) after valve operation (OPEN), and the intake return tension spring (90) enables a limp home operation to return the intake valve (80) to the default position (OPEN) when the EGR valve is closed (i.e., CLOSE operation) to return to the default position (OPEN) after valve operation (CLOSE).

Meanwhile, FIGS. 3 to 5 show examples in which an EGR system (200) applied to an engine system (100) is composed of a three-way EGR valve unit (1).

Referring to FIG. 3, the engine system (100) includes an EGR system (200), and the EGR system (200) supplies a portion of exhaust gas as EGR gas to a three-way EGR valve unit (1) while supplying air flow to a combustion chamber of the engine.

For example, the above three-way EGR valve unit (1) is the three-way EGR valve unit (1) described in FIGS. 1 and 2.

For example, the above engine system (100) is composed of an intake device that supplies a mixture (new air + exhaust gas) to a combustion chamber centered on the engine, and an exhaust device that discharges exhaust gas of the engine.

For example, the EGR system (200) mixes the intake (i.e., fresh air) of the intake and the EGR gas, which is part of the exhaust gas, before the mixture (fresh air + exhaust gas) is supplied to the combustion chamber of the engine and is supplied to the combustion chamber.

In particular, the above EGR system (200) is an LP (Low Pressure) EGR system that extracts a portion of exhaust gas from an exhaust pipe at the rear end of a turbocharger and a catalyst and supplies it as EGR gas.

Referring to Fig. 4, the three-way EGR valve unit (1) operates in valve initial position (A), opening control (B), and closing control (C).

For example, the above valve initial position (A) is EGR fully closed, EGR valve (40) opening degree 0°/intake valve (80) throttle opening degree 0°.

Next, the above-described opening control (B) operates the EGR valve (40) through the EGR valve shaft (41) by the rotation of the segment gear (30) by the driving force of the motor (10) and the reducer (20), and the opening degree of the EGR valve (40) is 86°. The rotation of the rotation arm (60) by the ball bearing (60) in contact with the profile (30A) of the segment gear (30) operates the intake valve (80) through the intake valve shaft (81), so that the throttle opening degree of the intake valve (80) is formed as the EGR fully closed position.

On the other hand, the above closing control (C) returns the EGR valve (40) to the opening degree of 0° by restoring the segment gear (30) through the operation of the reverse rotation of the motor (10) and the reducer (20), and returns the intake valve (80) to the throttle opening degree of 0° by the elastic restoring force of the intake return tension spring (90).

In particular, when the EGR valve is closed (i.e., CLOSE operation) in a motor failure state, the EGR return tension spring (50) enables a limp home operation in which the EGR valve (40) returns to the default position by rotating the segment gear (30) clockwise with elastic restoring force, and the intake return tension spring (90) enables a limp home operation in which the intake valve (80) returns to the default position by rotating the rotation arm (60) counterclockwise with elastic restoring force.

As described above, the spring-type wear prevention type 3-way EGR valve unit (1) applied to the EGR system (200) according to the present embodiment opens and closes the EGR (Exhaust Gas Recirculation) flow port (5) with the EGR valve (40) of the EGR valve shaft (41) fixed to the segment gear (30) by the driving force of the motor and reducer built into the valve housing (3), opens and closes the air flow port (7) with the intake valve (80) of the intake valve shaft (81) fixed to the rotation arm (60) together with the ball bearing (70) in contact with the profile (30A) rotated by the segment gear (30), and returns the EGR valve (40) to the default position when restored after being tensioned in the rotational direction of the segment gear (30). And by including an intake return tension spring (90) that returns the intake valve (80) to the default position after tensioning and restoring in the rotational direction of the rotation arm (60), the valve operation failure (STUCK) due to internal wear foreign substances is eliminated by removing the spring sliding part inside the valve housing, and in particular, by eliminating the torsion spring mounting space in the internal space of the valve housing, the degree of freedom in the layout of valve parts is greatly improved, and the size of the finished product is also reduced by reducing the axial length of the EGR valve and intake valve.

1:3 way EGR valve unit
3: Valve housing 5: EGR flow port
7: Air flow port 10: Motor
20: Reducer 30: Segment Gear
30A : Profile 40 : EGR valve
41: EGR valve shaft 50: EGR return tension spring
51: Valve housing upper hook 52: Segment gear hook
60: Rotation arm 70: Ball bearing
80 : Intake valve 81 : Intake valve shaft
90: Intake return tension spring 91: Valve housing lower hook
92: Rotation Arm Hook 95: Axis Boss
100 : Engine System 200 : EGR System

Claims (14)

Valve housing with EGR (Exhaust Gas Recirculation) flow port and air flow port;
An EGR valve coupled to an EGR valve shaft having a segment gear fixed thereon, which is rotated by the driving force of a motor and a reducer, and which opens and closes the EGR flow port by counterclockwise rotation of the segment gear;
An intake valve coupled to a rotation arm fixed with a ball bearing in contact with a profile that is rotated by the above segment gear, and opening and closing the air flow port according to the rotation direction of the rotation arm;
When the EGR valve is opened by counterclockwise rotation of the segment gear, the EGR return tension spring is tensioned by the segment gear; and
When the intake valve is closed by clockwise rotation of the rotation arm, an intake return tension spring is included that is tensioned by the rotation arm.
The EGR return tension spring is positioned on the upper surface of the segment gear in the segment gear receiving space of the valve housing, and the intake return tension spring is positioned on the upper surface of the rotation arm in the rotation arm receiving space of the valve housing.
A three-way EGR valve unit, characterized in that the EGR return tension spring has a lower space of the segment gear located on the upper surface as the EGR shaft hub space length of the shaft hub, the intake return tension spring has a lower space of the rotation arm located on the upper surface as the intake shaft hub space length of the shaft hub, and the valve axis distance of the EGR valve shaft formed by the valve housing and the intake valve shaft is formed by the size of the EGR shaft hub space length and the intake shaft hub space length.
A three-way EGR valve unit according to claim 1, characterized in that the EGR return tension spring, when restored after being tensioned by the segment gear, rotates the segment gear clockwise to return the EGR valve to the default position.
delete A three-way EGR valve unit according to claim 2, characterized in that one end of the EGR return tension spring is fixed by a valve housing upper hook formed in the valve housing, and the other end is fixed by a segment gear hook formed on an upper surface of the segment gear.
A three-way EGR valve unit according to claim 4, characterized in that each of the valve housing upper hook and the segment gear hook has a protruding structure.
A three-way EGR valve unit according to claim 4, characterized in that the segment gear hook is located in a lower area of the segment gear.
A three-way EGR valve unit according to claim 1, characterized in that the intake return tension spring, when restored after being tensioned by the rotation arm, rotates the rotation arm counterclockwise to return the intake valve to the default position.
delete A three-way EGR valve unit according to claim 7, characterized in that the intake return tension spring has one end fixed by a valve housing lower hook formed in the valve housing, and the opposite end fixed by a rotation arm hook formed on an upper surface of the rotation arm.
A three-way EGR valve unit according to claim 9, characterized in that each of the valve housing lower hook and the rotation arm hook has a protrusion structure.
A three-way EGR valve unit according to claim 9, characterized in that the rotation arm hook is located in a lower area of the rotation arm.
In an EGR system applying a three-way EGR valve unit according to any one of claims 1, 2, 4 to 7, and 9 to 11,
A three-way EGR valve unit is provided, comprising: an EGR valve of an EGR valve shaft fixed to a segment gear that is rotated by the driving force of a motor and a reducer built into a valve housing, which opens and closes an EGR (Exhaust Gas Recirculation) flow port; an intake valve of an intake valve shaft fixed to a rotation arm with a ball bearing in contact with a profile that is rotated by the segment gear, which opens and closes an air flow port; an EGR return tension spring that returns the EGR valve to a default position when tensioned and then restored in accordance with the rotational direction of the segment gear; and an intake return tension spring that returns the intake valve to a default position when tensioned and then restored in accordance with the rotational direction of the rotation arm.
When the valve of the above 3-way EGR valve unit is opened,
An EGR system characterized in that it sends the EGR gas flow rate from the EGR flow port and the air flow rate from the air flow port to the engine of the engine system.
An EGR system according to claim 12, characterized in that the EGR flow port and the air flow port have a 90° arrangement layout.
An EGR system according to claim 12, characterized in that the EGR valve is a low pressure EGR valve type that extracts some of the exhaust gas flowing through the exhaust pipe of the engine system at a position after the turbocharger and supplies it as EGR gas.