DIVERT AIR VALVE FOR AN INTERNAL COMBUSTION ENGINE

Abstract

A divert air valve for an internal combustion engine arranged in a bypass channel between a pressure side and a suction side of a supercharging device includes a housing. A bypass valve comprises a first valve closure body. A control pressure chamber is connected with the pressure side through a compensation opening. A solenoid valve comprises a coil body, a magnetic yoke arrangement, an armature, and a second valve closure body which comprises a second spring element and cooperates with the armature. When the solenoid valve is energized and the bypass valve open, a fluidic communication can be established between the pressure side and the suction side or the atmosphere through the control pressure chamber. An overall cross section of the at least one control opening is larger than a cross section of the compensation opening. A closing of the fluidic communication causes a resultant force in a closing direction.

Description

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C. §371 of International Application No. PCT/EP2011/054301, filed on Mar. 22, 2011 and which claims benefit to German Patent Application No. 10 2010 024 297.7, filed on Jun. 18, 2010. The International Application was published in German on Dec. 22, 2011 as WO 2011/157457 A1 under PCT Article 21(2).

FIELD

The present invention relates to a divert air valve for an internal combustion engine, which is arranged in a bypass duct between the pressure side and the suction side of a supercharging device, comprising a bypass valve with a pneumatically actuable first valve closure body biased in the closing direction by a spring force, a control pressure chamber which, in the closed state of the bypass valve, is in communication with the pressure side via a permanently open compensation opening, and comprising a solenoid valve with a coil body, a magnetic yoke arrangement and an armature that is also biased in the closing direction, as well as a cooperating second valve closure body for at least one control opening, wherein, by energizing the solenoid valve during the opening process of the bypass valve, a fluidic communication between the pressure side and the suction side of the supercharging device can be established via the control pressure chamber.

BACKGROUND

Divert air valves for the recirculation of compressed combustion gas from the pressure side of a compressor of a turbocharger back to the suction side of the compressor are generally known as divert air valve devices. The connection between the pressure side and the suction side of the compressor via a bypass line is required for the transition from a high load to the overrun condition of the internal combustion engine, in order to avoid a high output of the charge pressure pump against a closed throttle valve and the pump effect resulting therefrom, as well as an overly strong, abrupt reduction of the turbo speed with the ensuing consequences of thermodynamic problems.

Divert air valves are often operated electromagnetically, with the valve closure body of the valve being moved by the electromagnetic force. An example for such an arrangement is described in DE 100 20 041 A1. The control is effected through a control unit according to available engine data. The valve comprises a pressure equalization opening at the valve closure body, whereby a balance of forces is established with respect to the pneumatic forces, given a corresponding design of the effective surfaces. However, these valves have a drawback in that, despite the pressure equalization unit of the valve, a great actuation force is required to actuate the valve closure body during the opening, where large solenoids have to be used in particular when the cross sections to be switched are large. There are at the same time limitations with respect to the opening times achievable.

In the interest of reducing the necessary magnetic force, DE 102 51 981 A1 describes providing a pneumatically actuated divert air valve whose control pressure chamber can be connected with the suction side of the compressor via a solenoid valve. This leads to the opening of the valve. However, the pressure difference responsible therefor decreases in the open state, so that an unintentional closing of the valve can occur.

DE 10 2005 028 141 A1 describes a bypass valve for internal combustion engines wherein an opening of the valve closure body is obtained by electromagnetically lifting a sealing plate from openings via which a fluidic communication of the control pressure chamber to the suction side of the compressor can be established. In addition, a permanent connection exists between the control pressure chamber and the pressure side via a pressure equalization opening in the valve closure body. However, since the latter has a smaller cross section than the openings to the suction side, a force acting in the opening direction is generated that causes the valve closure body to open. In the open state, however, the valve closure body again abuts against the sealing plate so that a pressure equilibrium forms at the valve closure body. This may lead to an unintentional closing of the valve due to a spring force acting in the closing direction. Pressure thereafter builds up again, so that the valve again opens due to the pressure difference. A control circuit comprising a valve that opens and closes is formed, which results in increased wear.

SUMMARY

An aspect of the present invention is to provide a divert air valve with which the above-mentioned drawbacks can be avoided, a defined position of the valve closure body provided when the solenoid is activated, while having as simple a structure as possible.

In an embodiment, the present invention provides a divert air valve for an internal combustion engine. The divert air valve is arranged in a bypass channel between a pressure side and a suction side of a supercharging device. The divert air valve includes a housing. A bypass valve comprising a first valve closure body is configured to be pneumatically actuable and to be biased in a closing direction by a first spring element. A control pressure chamber is, in the closed state of the bypass valve, connected with the pressure side through a compensation opening which is configured to be permanently open. A solenoid valve comprises a coil body, a magnetic yoke arrangement, an armature configured to be biased in the closing direction, and a second valve closure body for at least one control opening. The second valve closure body comprises a second spring element and is configured to cooperate with the armature. When the solenoid valve is in an energized state, so that the bypass valve is open, a fluidic communication can be established between the pressure side and the suction side of the supercharging device or the atmosphere through the control pressure chamber. An overall cross section of the at least one control opening is larger than a cross section of the compensation opening, such that, when the bypass valve is open, a fluidic communication exists at least temporarily between the pressure side and the suction side of the supercharging device via the control pressure chamber. A closing of the fluidic communication causes a resultant force in a closing direction.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is described in greater detail below on the basis of embodiments and of the drawings in which:

FIG. 1 shows a sectional view of a bypass valve of the present invention.

DETAILED DESCRIPTION

By providing a first spring element for the first valve closure body and a second spring element for the second valve closure body, with the total cross section of the control opening(s) being larger than the cross section of the compensation opening, it is possible to establish, at least temporarily, a fluidic communication between the pressure side and the suction side of the supercharging device via the control pressure chamber when the bypass valve is fully open, wherein a closing of the fluidic communication causes a resulting force in the closing direction, whereby a defined opening and closing of the bypass valve is achieved. An unintentional closing or pulsating of the valve closure body is reliably avoided. At the same time, a simple and thus economic structure of the divert air valve is provided.

In an embodiment of the present invention, the coil body can, for example, comprise the control opening. This allows for an internal flow through the divert air valve. The second spring element may advantageously be supported on the magnetic yoke arrangement.

From a manufacturing point of view, it is advantageous if the armature is formed as a cylinder substantially open at one side, the second valve closure body being formed at the base of the cylinder. It is also advantageous to provide a solenoid valve housing comprising a fastening member arranged in the housing in a sealed manner. The solenoid valve housing may here be clamped using the fastening member. The first spring element can advantageously be supported at the fastening member.

The fact that the housing comprises a terminating element fixing the solenoid valve housing in the axial direction allows for a simple assembly of the divert air valve.

An embodiment is illustrated in the drawing.

The divert air valve 1 of the present invention essentially comprises a housing 16 in which a bypass valve 2, a solenoid valve 4 and a control pressure chamber 24 are arranged. Under interposition of a seal 9, the divert air valve 1 is flanged directly to a channel-forming housing 6 of a bypass channel 8 non-illustrated supercharger device of an exhaust gas turbo charger, which bypass channel 8 serves as a recirculation channel. The recirculation or bypass channel 8 may be formed either directly in the housing of the supercharger device or as an external channel.

The bypass valve 2 comprises a pneumatically actuable first valve closure body 10 that separates a pressure side 12 against which the first valve closure body 10 abuts, from a laterally positioned suction side 14 of the bypass channel 8 of the supercharger device. The first valve closure body 10 is biased in the closing direction by means of a first spring element 18.

In the closed state, a sealing lip 32 of the first valve closure body 10 rests on a valve seat 34 formed in the channel-forming housing 6. The valve closure body 10 further comprises at least one permanently open defined compensation opening 36 through which the control pressure chamber 24 is in communication with the pressure side 12, when the valve is in the closed state. As a result, in the closed state, the same pressure acts in the control pressure chamber 16 as on the pressure side 12 below the valve closure body 10. In this manner, in the closed state, the bypass valve 2 is substantially balanced with respect to the pneumatic forces. The bypass valve 2 is accordingly maintained in the closed state by the spring force of the first spring element 18.

In order to also be able to open the bypass valve 2, the housing is further provided with the solenoid valve 4 that comprises a coil body 20, a magnetic yoke arrangement 22 and an armature 23 also biased in the closing direction, as well as a second valve closure body 26 for at least one control opening 38, which cooperates with the armature. In the present embodiment, this control opening is provided in the coil body 20, the cross section of the control opening 38 being larger than the cross section of the compensation opening 36.

The armature 23 is substantially designed as a cylinder open on one side, with the second valve closure body 26 being formed at the base 25 thereof. A second spring element 27 exerts a spring force in the closing direction on the armature and thus on the second valve closure body and is supported at the magnetic yoke arrangement of the solenoid valve.

The solenoid valve 4 further comprises a solenoid valve housing 28 with an integrally-connected fastening element 30, which in the present embodiment is clamped sealingly into the housing 16. The fastening element 30 also thus provides the support surface for the first spring element 18. A seal 40 for the first valve closure body 10 is further supported in the fastening element 30. The control pressure chamber is accordingly defined by the interior of the first valve closure body 10, the space between the fastening element 30 and the outer surface of the solenoid valve housing 28, as well as the interior of the solenoid valve 4.

Towards the suction side 14, the housing of the divert air valve 1 is closed by a termination element 42 which is clamped in the housing 16 and fixes the solenoid valve housing 28 in the axial direction. It is also possible to provide a welding, soldering or other releasable or permanent connection instead of the clamping connection. The termination element 42 has further openings 44 via which, when the second valve closure body 26 is open, the control pressure chamber 24 is in communication with the suction side 14 through the control opening 38.

The divert air valve 1 of the present invention operates as follows:

Upon energization of the solenoid valve 4, the armature 23 is moved against the closing direction of the second spring element 27, whereby the control opening 38 is cleared. The gas in the control pressure chamber 24 escapes, since the pressure in the control pressure chamber 24 is higher than on the suction side 14 of the supercharging device. At the same time, the volume of gas flowing in through the compensation opening 36 is smaller because of the smaller cross section so that a pressure drop occurs in the control pressure chamber 24, whereby a pressure gradient occurs at the first valve closure body 10 causing a resultant force at the valve closure body 10 in the opening direction of the bypass valve 2. The valve closure body 10 is accordingly lifted from the valve seat 34 and the bypass valve 2 opens.

If the pressure difference between the pressure side 12 and the suction side 14 in the recirculation channel 8 subsequently shifts towards pressure equalization, the pressure in the control pressure chamber 24 also drops, since gas of lower pressure flows in through the opening 36. However, a pressure gradient always exists in the open state of the solenoid valve 4 due to the different cross sections of the compensation opening 36 and the control opening 38, which pressure gradient provides that the bypass valve 2 does not close unintentionally.

When the solenoid valve 4 is again closed, a pressure equalization occurs between the bottom side of the first valve closure body 10 and the control pressure chamber 24. This results in a pneumatic pressure equalization and thus results in a balance of the pneumatic forces. As a consequence, the bypass valve 2 is closed by the force of the first spring element 28. This state of pressure balance remains until the control opening 38 is again opened by the solenoid valve 4.

It should be noted that other embodiments of the divert air valve 1 are conceivable without leaving the scope of protection of the main claim. In particular, the control opening 38 can also be connected to atmosphere.

The present invention is not limited to embodiments described herein; reference should be had to the appended claims.

Claims

1-8. (canceled)

9. A divert air valve for an internal combustion engine, the divert air valve being arranged in a bypass channel between a pressure side and a suction side of a supercharging device, the divert air valve comprising:

a housing;

a bypass valve comprising a first valve closure body which is configured to be pneumatically actuable and to be biased in a closing direction by a first spring element;

a control pressure chamber which, in the closed state of the bypass valve, is connected with the pressure side through a compensation opening which is configured to be permanently open; and

a solenoid valve comprising a coil body, a magnetic yoke arrangement, an armature configured to be biased in the closing direction, and a second valve closure body for at least one control opening, the second valve closure body comprising a second spring element and being configured to cooperate with the armature;

wherein, when the solenoid valve is in an energized state so that the bypass valve is open, a fluidic communication can be established between the pressure side and the suction side of the supercharging device or the atmosphere through the control pressure chamber,

wherein an overall cross section of the at least one control opening is larger than a cross section of the compensation opening, such that, when the bypass valve is open, a fluidic communication exists at least temporarily between the pressure side and the suction side of the supercharging device via the control pressure chamber, whereby a closing of the fluidic communication causes a resultant force in a closing direction.

10. The divert air valve as recited in claim 9, wherein the coil body comprises the at least one control opening.

11. The divert air valve as recited in claim 9, wherein the second spring element is supported at the magnetic yoke arrangement.

12. The divert air valve as recited in claim 9, wherein the armature is provided substantially as a cylinder which is open on one side and which comprises a base, wherein the second valve closure body is formed at the base.

13. The divert air valve as recited in claim 9, further comprising a solenoid valve housing comprising a fastening element, the solenoid valve housing being arranged in the housing so as to be sealed.

14. The divert air valve as recited in claim 13, wherein fastening element is configured to clamp the solenoid valve housing.

15. The divert air valve as recited in claim 13, wherein the first spring element is configured to be supported on the fastening element.

16. The divert air valve as recited in claim 13, wherein the housing comprises a termination element configured to fix the solenoid valve housing in an axial direction.