Control system of at least one flap of a fluid duct and fluid duct system

Abstract

A control system of at least one flap of a fluid duct of an intake system of an internal combustion engine, including: a swivel axis, at least one flap connected off-center to the swivel axis by which the at least one flap can be swiveled within the fluid duct between positions with different degrees of opening, a swivel lever connected to the swivel axis, the swivel lever pivoting the swivel axis, an elastic working return element connected directly or indirectly to the swivel lever and applying a force to the at least one flap to return the at least one flap toward a home position.

Claims

1. A control system of at least one flap of a fluid duct of an intake system of an internal combustion engine, comprising: a swivel axis; a rotation axis; at least one flap swivel-mounted directly on the swivel axis, mounted in an interior of the fluid duct, the flap rotating on the swivel axis, the at least one flap connected offcenter to the swivel axis by which the at least one flap swivels within the fluid duct between positions with different degrees of opening; a swivel lever connected to the swivel axis, the swivel lever pivoting the swivel axis; an actuating lever having a first end rotatably mounted to a housing part of the fluid duct and configured to swivel with the at least one flap, the actuating lever rotating around the rotation axis, the actuating lever having: a working surface; a spring acting as an elastic working return element connected indirectly to the swivel lever through the actuating lever, the spring having a first end resting directly on and apply a force to the working surface of the actuating lever, the spring applying a linearly aligned force to the at least one flap to return the at least one flap toward a home position; wherein the rotation axis, the connection axis and the swivel axis are parallel to each other; wherein a radial distance between the swivel axis and the working surface is varying dependent on the opening/closing position of the at least one flap; wherein the at least one flap is moved passively within the fluid duct between an open position and a closed position by an action of a differential pressure force of fluid pressures upstream and downstream of the flap, the differential pressure force acting against the linearly aligned force of the spring to position the at least one flap to the different degrees of opening, the differential pressure force and the linearly aligned force of the spring working alone to passively move the at least one flap without other actuating elements.

2. The control system according to claim 1, wherein the distance between the rotation axis and the connection axis and/or between the swivel axis and the connection axis and/or between the working surface and the connection axis and/or between the working surface and the rotation axis is varying automatically dependent on the opening/closing position of the at least one flap.

3. The control system according to claim 1, wherein the actuating lever includes an elongated guidance element in the form of a long hole forming a guidance groove or slot; and wherein the swivel lever includes an actuating element in the form of a pivot pin or rod which is moveably arranged in the long hole of the guidance element; wherein the actuating element realizes the connection axis.

4. The control system according to claim 3, wherein the guidance element extends radially in the actuating lever relative to the rotation axis.

5. The control system according to claim 3, wherein the guidance element is at least partially is curved.

6. The control system according to claim 1, wherein the working surface is arranged between the connection axis and the rotation axis.

7. The control system according to claim 1, wherein the working surface and the swivel axis of the flap are on opposite ends of the actuating lever.

8. The control system according to claim 1, wherein the elastic working return element includes at least one bias element.

9. A fluid duct system of an internal combustion engine, comprising: at least one fluid duct; a control system of at least one flap, including: a swivel axis; a rotation axis; at least one flap swivel-mounted directly on the swivel axis, mounted in an interior of the fluid duct, the flap rotating on the swivel axis, the at least one flap connected offcenter to the swivel axis by which the at least one flap swivels within the fluid duct between positions with different degrees of opening; a swivel lever connected to the swivel axis, the swivel lever pivoting the swivel axis; an actuating lever having a first end rotatably mounted to a housing part of the fluid duct and configured to swivel with the at least one flap, the actuating lever rotating around the rotation axis, the actuating lever having: a working surface; a spring acting as an elastic working return element connected indirectly to the swivel lever through the actuating lever, the spring having a first end resting directly on and apply a force to the working surface of the actuating lever, the spring applying a linearly aligned force to the at least one flap to return the at least one flap toward a home position; wherein the rotation axis, the connection axis and the swivel axis are parallel to each other; wherein a radial distance between the swivel axis and the working surface is varying dependent on the opening/closing position of the at least one flap; wherein the at least one flap is moved passively within the fluid duct between an open position and a closed position by an action of a differential pressure force of fluid pressures upstream and downstream of the flap, the differential pressure force acting against the linearly aligned force of the spring to position the at least one flap to the different degrees of opening, the differential pressure force and the linearly aligned force of the spring working alone to passively move the at least one flap without other actuating elements.

10. The fluid duct system according to claim 9, wherein the fluid duct system has at least two fluid ducts.

11. The fluid duct system according to claim 10, wherein at least one of at least two fluid ducts has a different flap and/or control system or no flap and/or no control system.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiments, but not restricted to the embodiments, wherein is shown schematically

(2) FIG. 1 an intake system of an internal combustion engine of a motor vehicle including an air filter and an air duct system with two air ducts, wherein one of the air ducts has a flap with a control system;

(3) FIG. 2 a local section of the air duct system of FIG. 1, wherein the flap is closed;

(4) FIG. 3 the local section of the air duct system of FIG. 2 from a different angle;

(5) FIG. 4 the local section of the air duct system of FIG. 2, wherein the flap is half-opened;

(6) FIG. 5 the local section of the air duct system of FIGS. 2 and 4, wherein the flap is fully opened;

(7) FIG. 6 a local section of an air duct system with an alternative control system for the flap.

(8) In the drawings, equal or similar elements are referred to by equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. Moreover, the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention.

SUMMARY OF INVENTION

(9) FIG. 1 depicts an air intake system 10 of an internal combustion engine of a motor vehicle including an air filter 12 and an air duct system 14. The air duct system 14 is mounted upstream on a housing 16 of the air filter 12. An air outlet 18 of the housing 16 of the air filter 12 is connected by a not shown clean air pipe with the internal combustion engine. In FIGS. 2 to 5 the air duct system 14 is shown in different perspectives and operational states.

(10) The air duct system 14 has two air ducts, namely a main air duct 20 and a bypass air duct 22. The air ducts 20 and 22 are parallel relating to an air flow. Thus, air can flow through one or both air ducts 20 and 22. The air ducts 20 and 22 have approximately equal cross-section areas over their whole length. Each air duct 20 and 22 leads to an air inlet of the housing 16 of the air filter 12, which is hidden in FIG. 1.

(11) A flap 24 is inside of the bypass air duct 22. With the flap 24 a current of combustion air through the bypass air duct 22 can be affected. The main air duct 20 has no flap.

(12) The flap 24 is shaped accordant to the interior surface of the bypass air duct 22. The flap 24 is swivel-mounted to the bypass air duct 22 by a swivel axis 26. The swivel axis 26 is connected off-centered to the flap 24. The swivel axis 26 is part of a two-lever-control system 28 for controlling the flap 24. The flap 24 can be swiveled by the swivel axis 26 between positions with different degrees of opening. In its closed position, shown in FIGS. 1 to 3, the flap 24 closes the orifice completely. The closed position is the home position of the flap 24. In its open position, shown in 5, the flap 24 lies substantially parallel to a longitudinal axis of the bypass air duct 22.

(13) The swivel axis 26 is pivot-mounted in the housing of the bypass air duct 22. Outside the bypass air duct 22, one end of the swivel axis 26 is fixed to an elongated swivel lever 30. The swivel axis 26 can be pivoted by the swivel lever 30. Contrariwise the swivel lever 30 can be swiveled by the swivel axis 26. The swivel lever 30 extends perpendicular to the swivel axis 26 approximately parallel to a plane of the flap 24. A free end of the swivel lever 30 thereby is on the same side of the swivel axis 26 like the flap 24.

(14) A connection axis 32 realized by a pivot is fixed permanently to the swivel lever 30 near its free end. The connection axis 32 is parallel to the swivel axis 26. It extends on the side of the swivel lever 30, which is opposite to the flap 24.

(15) A distance 34 radial to the swivel axis 26 between the swivel axis 26 and the connection axis 32 is constant. For the sake of clarity, the radial distance 34 is marked only in FIG. 4 with a reference numeral. The radial distance 34 is 12 mm.

(16) Further, the control system 28 has an elongated actuating lever 36. The actuating lever 36 is mounted to the housing of the bypass air duct 22 swiveling round a rotation axis 38. The rotation axis 38 is realized by a machine bolt. The rotation axis 38 is parallel to the swivel axis 26 and parallel to the connection axis 32. The rotation axis 38 is arranged on a side of the bypass air duct 22 which circumferential is far from the swivel axis 26. The actuating lever 36 is perpendicular to the rotation axis 38, to the connection axis 32 and to the swivel axis 26 each. In the closed position of the flap 24 the actuating lever 36 extends approximately tangential to the radial outer circumferential side of the bypass air duct 22.

(17) The actuating lever 36 has near its end which is opposite to the rotation axis 38 a long hole 40. The long hole 40 serves as a guidance element for the connection axis 32. The long hole 40 has a straight shape. In longitudinal direction the long hole 40 extends radial to the rotation axis 38 from radial inside to radial outside.

(18) The connection axis 32 is supported shiftable in the long hole 40. In the guidance groove of the long hole 40 the connection axis 32 is guided on opposite sides. The actuating lever 36 is mounted to the swivel lever 30 swiveling round the connection axis 32 in the long hole 40.

(19) A distance 42 radial to the rotation axis 38 between the rotation axis 38 and the connection axis 32 can be changed automatically dependent on the opening/closing position of the flap 24. This radial distance 42 can vary between approximately 45 mm and 60 mm. In the closing position of the flap 24 the radial distance 42 is 45 mm.

(20) A ratio of the radial distance 42 between the rotation axis 38 and the connection axis 32 to the radial distance 34 between the swivel axis 26 and the connection axis 32 can be between approximately 45/12 and 60/12.

(21) The actuating lever 36 further has a working surface 44 in which a return element 46 applies to the actuating lever 36. The working surface 44 and the swivel axis 26 are on opposite sides of the actuating lever 36. The working surface 44 is between the connection axis 32 and the rotation axis 38 nearby the rotation axis 38.

(22) A distance radial to the rotation axis 38 between the rotation axis 38 and a center of the working surface 44 is constant. This radial distance 48 is 15 mm.

(23) A ratio of the radial distance 34 between the swivel axis 26 and the connection axis 32 to the radial distance 48 between the rotation axis 38 and the working surface 44 is constant. It is approximately 4/5.

(24) A distance radial to the connection axis 32 between the working surface 44 and the connection axis 32 is also varying automatically dependent on the opening/closing position of the flap 24.

(25) A length of the respective lever arms for realizing a respective torque at a respective axis is defined by the respective radial distances 34, 42 and 48 of the axis/working surface each.

(26) The return element 46 is realized by an elastic working helical compression spring. The return element 46 rests with one end on the working surface 44 of the actuating lever 36. With the other end the return element 46 rests on a support 50 of the housing of the bypass air duct 22. The return element 46 is prestressed. The spring constant of the return element 46 is around 1414 N/m.

(27) A force transmission from the return element 46 to the actuating lever 36 is almost tangential to a virtual circle around the rotation axis 38. In the closed position of the flap 24 a direction of the force caused by the return element 46 is almost perpendicular to a plane which is spanned by the rotation axis 38 and the connection axis 32. The return element 46 causes a force which can effect a torque acting on the rotation axis 38 and/or the connection axis 32.

(28) The return element 46 is connected indirectly by the actuating lever 36 to the swivel lever 30. Thus, the return element 46 can cause a force which effects a respective torque on the swivel axis 26. The return element 46 forces the at least one flap 24 toward its close position.

(29) Combustion air is sucked into the main air duct 20 during operation of the internal combustion engine. The flow direction of the combustion air is indicated in FIG. 1 by an arrow 52.

(30) Initially, the bypass air duct 22 is closed by the flap 24. With help of the swivel lever 30 and the actuating lever 36 the return element 46 forces the flap 24 against external forces in its home position. External forces can be caused for example by a pressure difference on opposed sides of the flap 24. The torque applied on the swivel axis 26 is caused by the force of the return element 46 and an opening force of the air flow acting on the flap 24.

(31) The flap 24 opens automatically when the air flow rate is exceeding a specific value. The flap 24 is controlled passively by the volume flow rate of the air through the bypass air duct 22.

(32) Dependent on operating conditions, the air flow through the bypass air duct 22 is controlled by the control system 28. The direction of any air flow through the bypass air duct 22 is indicated in FIG. 1 by an arrow 54. FIG. 4 shows the flap 24 in half open position. In FIG. 5 the flap 24 is shown in its open position.

(33) For opening, the flap 24 swivels in direction 54 of the air flow. Thereby, it turns the swivel axis 26. The swivel axis 26 swivels the swivel lever 30. With the connection axis 32, the swivel lever 30 swivels the actuating lever 36 against the force of the return element 46.

(34) During the opening process of the flap 24, the connection axis 32 is guided along the long hole 40. The connection axis 32 is moved away from the rotation axis 38 and the working surface 44. The course of the long hole 40 is predetermined in order to achieve specific opening/closing characteristics of the flap 24.

(35) By the movement of the connection axis 32 in the long hole 40, the relationship of the levers is varying during the movement of the flap 24. The torque on the swivel axis 26 varies dependent on the opening/closing position of the flap 24.

(36) The opening/closing position of the at least one flap 24 corresponds to a rotation angle of the swivel axis 26. So the torque is depend on the rotation angle. A course of torque dependent on the rotation angle of the swivel axis 26 is a kind of sinusoidal. The torque has a maximum at a rotation angle of 0 based on the close position of the flap 24. The torque has a reduced value at a rotation angle which corresponds to an degree of opening of the flap 24 of 70%.

(37) When the air mass flow decreases the return element 46 with help of the actuating lever 36, the swivel lever 30 and the swivel axis 26 returns the flap 24 in direction of its close position.

(38) Combustion air always can flow through the main air duct 20. The bypass air duct 22 is switched on and off into a kind of bypass mode.

(39) FIG. 6 depicts a second embodiment of a control system 28. Different to the first embodiment, in the second embodiment a long hole 140 is curved. A radial outer face of the curved long hole 140 faces the swivel axis 26.