WO2014082778A1

WO2014082778A1 - Exhaust gas turbocharger

Info

Publication number: WO2014082778A1
Application number: PCT/EP2013/070774
Authority: WO
Inventors: Andreas Kellner
Original assignee: Robert Bosch Gmbh
Priority date: 2012-11-29
Filing date: 2013-10-07
Publication date: 2014-06-05
Also published as: DE102012221911A1

Abstract

The invention relates to an exhaust gas turbocharger (1), in particular for a motor vehicle, having a turbine (2), which can be driven by an exhaust gas stream and which has a compressed oil supply (10) comprising lubricant to lubricate moving parts and an actuation device (8) for influencing the exhaust gas stream, wherein the actuation device (8) is associated with a servo (9). According to the invention the servo (9) has a hydraulic cylinder (11), which is functionally connected to the actuation device (8) and is functionally connected or can be functionally connected to the compressed oil supply (10) by means of a valve (18) that can be actuated.

Description

turbocharger

The invention relates to an exhaust gas turbocharger, in particular for a motor vehicle, having a turbine which can be driven by an exhaust gas stream and which has a

Compression oil supply with lubricant, in particular oil, for the lubrication of moving parts and an adjusting device for influencing the exhaust gas flow, wherein the actuating device is associated with an actuator.

PRIOR ART Exhaust gas turbochargers of the type mentioned in the introduction are known from the prior art. They have a turbine, which is an exhaust gas flow of a

Internal combustion engine is supplied to drive the turbine. The turbine is in turn fixedly connected via a shaft to a compressor which, driven by the turbine, compresses fresh air and supplies it to the internal combustion engine. To increase the efficiency of the internal combustion engine and legal

To comply with specifications on pollutants in the exhaust gas, it is known to assign the turbine of an exhaust gas turbocharger an adjusting device which influences the exhaust gas flow supplied to the turbine by passing it either wholly or partially past the turbine, so-called "waste gate" principle, or the

Flow angle changed by means of a variable turbine geometry. In both

Cases, the performance of the turbine and thus the turbocharger is influenced.

A corresponding exhaust-gas turbocharger is known, for example, from DE 10 201 1 904 027 A1. The adjusting device is characterized by an electromotive

Actuator actuated. Also solutions are known in which the actuator is pneumatically formed. However, the previous solutions usually have an unfavorable design and are so far difficult to integrate into the rest of the geometry of the exhaust gas turbocharger. Disclosure of the invention

The exhaust gas turbocharger according to the invention with the features of claim 1 has the advantage that the actuator no separate power source needed and can be easily and compactly integrated into the exhaust gas turbocharger. According to the invention, provision is made here for the actuator to have a hydraulic cylinder operatively connected to the adjusting device, which is operatively connected / operatively connected to the pressure oil supply of the exhaust gas turbocharger by an actuatable valve. The actuator thus uses the exhaust gas turbocharger anyway available

Pressure oil supply as a source of power us through the valve with the

Connect pressure oil supply to be actuated by the lubricant. The valve is thus interposed between the hydraulic cylinder and pressure oil supply of the exhaust gas turbocharger. The pressure in the pressure oil supply is sufficient to actuate the hydraulic cylinder and thus the adjusting device.

Preferably, the hydraulic cylinder has a cylinder tube with a piston axially displaceably mounted therein, which together at least one

Form pressure chamber, wherein the at least one pressure chamber is connected to the valve. The connection is a fluidic connection, so that provided by the pressurized oil supply and under

Pressurized oil with appropriate actuation of the valve in the

Pressure chamber is guided to exert there pressure on the piston to its operation. Preferably, at least one return spring is assigned to the piston. This makes it sufficient to generate the pressure in a pressure chamber to actuate the piston or the hydraulic cylinder, since the return spring ensures that the piston then returns to its original

Starting position is moved back. The return spring is designed in particular as a helical spring, in particular coaxial with the piston

is arranged.

According to an advantageous embodiment of the invention it is provided that the piston with the adjusting device, in particular with a lever of the

Setting device is connected by a hinge. The piston, only in one

Direction is axially displaceable, thus relative to the actuator, be shifted in particular to the lever to its operation. Through the joint in particular the linear movement of the piston in a

Rotary movement and thus converted into an actuating torque.

Particularly preferably, the joint is designed as a slot guide. For this purpose, the piston or the adjusting lever on a slot into which engages a arranged on the adjusting lever or on the piston slide pin, so that it is mounted longitudinally displaceable in the slot. It is thus a kind

Slotted link between piston and adjusting lever offered.

According to an advantageous embodiment of the invention it is provided that the valve is designed as a 3/2-way valve, with the pressure chamber, with the pressure oil supply and with a the oil of the pressure oil supply

collecting / storing tank is connected. The 3/2-way valve has three connections and two switch positions, between which it is adjustable. This makes it easy to operate the hydraulic cylinder and thus the actuator.

According to an alternative embodiment of the invention, it is preferably provided that the valve is designed as a 2/2-way valve. This valve thus also has two extreme line divisions, but only two ports, one of which is connected to the pressure oil supply and the other at least with the pressure chamber. This variant is less expensive to implement, since the valve itself is designed simpler.

Preferably, the hydraulic cylinder on two pressure chambers, wherein the 2/2-way valve is connected with an output to the pressure chamber directly and with the other pressure chamber and the tank through a throttle. The throttle ensures that the lubricant is first supplied to the pressure chamber and serves only secondarily to fill the other pressure chamber, so that always a correct actuation of the hydraulic cylinder is ensured.

Particularly preferably, the valve is designed as a proportional valve, so that it can take intermediate states between the extreme states, whereby, for example, the speed of movement of the piston adapted or a certain intermediate position of the piston can be maintained. Particularly preferred are the actuator and the adjusting device between the turbine and a drivable by the turbine compressor of the

Exhaust gas turbocharger arranged. Naturally there is space between the compressor and the turbine. While the provision of an electric motor drive in this space is not unproblematic due to the high temperatures, the invention provides the advantage of the pressure oil supply the advantage that the actuator is already exposed to high temperatures, namely the temperatures of the pressure oil. The actuation of the valve is preferably carried out electromagnetically, in which case no high power levels are required and insofar requirements for temperature resistance can be easily met.

In the following, the invention will be explained in more detail with reference to the drawing. To show:

1 shows an exhaust gas turbocharger in a schematic representation,

Figure 2 shows a first embodiment of an actuator of the

Exhaust gas turbocharger and

Figure 3 shows a second embodiment of the actuator in each case in a simplified representation. FIG. 1 shows a schematic top view of an exhaust gas turbocharger 1, which has a turbine 2 and a compressor 3. The turbine 2 has a housing arranged in the housing and a turbine wheel, which is fixedly connected via a turbocharger shaft with a compressor wheel of the compressor 3 (not visible). The turbine 2 is supplied via an inlet 4, an exhaust gas of an internal combustion engine, which drives the turbine wheel. Through an outlet 5 leaves the

Exhaust the turbine 2 then again. The compressor 3 has correspondingly an inlet 6 for fresh air, which is sucked in by the rotating compressor wheel and compressed out through an outlet 7 from the exhaust gas turbocharger 1 again led out and in particular the internal combustion engine is supplied. Furthermore, the exhaust gas turbocharger 1 has an adjusting device 8, which is designed to set a variable turbine geometry. By actuating the adjusting device 8, the angle of attack of the exhaust gas is adjusted to the turbine wheel and thereby influenced the exhaust gas flow such that the power of the turbine 2 is changed. By means of the adjusting device 8 can thus adjust the performance of the exhaust gas turbocharger. The digit direction 8 is a

Assigned actuator 9, which works hydraulically and this with a

Pressure oil supply 10 of the exhaust gas turbocharger 1 is connected. The

Pressure oil supply 10 serves to lubricate moving parts of the exhaust gas turbocharger, in particular the bearing associated with the turbocharger shaft with lubricant, in particular with oil. The pressure oil supply 10 can

For example, part of the oil circuit of the aforementioned

Be internal combustion engine, the pressure required for lubrication is generated for example by a corresponding pump.

In the following, the actuator 9 will be explained in more detail with reference to Figures 2 and 3. Figure 2 shows a first embodiment of the actuator 9 of the exhaust gas turbocharger 1 in a simplified representation. The actuator 9 has a hydraulic cylinder 1 1, which is formed by a cylinder tube 12 and a piston 12 axially displaceably mounted in the cylinder tube 12. The piston 13 protrudes at one end from the cylinder tube 12 with a piston rod 14 out. The piston rod 14 is sealed by means of a seal 15 on the cylinder tube, so that no medium can escape from the cylinder tube 12. On the opposite side of the piston rod 14, the piston 13 together with the cylinder tube 12 forms a first pressure chamber 16 and on the side of the piston rod 14, a second pressure chamber 17th

The actuator 9 further comprises an electromagnetically operable valve 18, which is designed as a 3/2-way proportional valve and this three

Ports 19, 20, 21 and between two extremal states switchable back and forth. Due to the design as a proportional valve, the valve 18 can also assume intermediate states.

The port 19 is connected to the pressure oil supply 10. The port 20 is connected to the first pressure chamber 16. The port 21 is provided with a tank 22 collecting the oil of the pressurized oil supply 10 or, alternatively, with a Return line of the pressure oil supply 10 connected. From the line leading to the tank 22 and the return line, another line leads to the second pressure chamber 17 of the hydraulic cylinder 1 first

The piston 13 is articulated by means of the piston rod 14 with a control lever 23 of the adjusting device 8. For this purpose, the piston rod 14 near its free end on a sliding pin 24 which is mounted longitudinally displaceable in a formed in the adjusting lever 23 slot 25. The slide pin 24 and the slot 25 thus together form a slot guide. An adjusting lever 23 associated with the angle sensor 26 detects the angle of rotation about which the adjusting lever 23 is adjusted about its axis of rotation 27 by the piston 13. A restoring spring 28, which in the present case is designed as a helical spring, is held pretensioned between one side of the adjusting lever 23 and a housing section 29 of the exhaust-gas turbocharger 1. The return spring 28 is thus indirectly associated with the piston 13, since it acts on the piston 13 via the adjusting lever 23.

The operation is as follows: In the illustrated state of the valve 18, the output 20 is connected to the output 21, so that the first

Pressure chamber 16 is depressurized. Since the second pressure chamber 17 is connected directly to the output 20, it is also depressurized. The return spring 28 thus urges the piston 13 in its initial position. By actuating the valve 18, this is brought into its second extreme state, so that the previously blinded output 19 connected to the output 20 and the output 21 is switched blind. Thus, the first pressure chamber 16 is connected to the pressure oil supply 10 and the first pressure chamber 16 is pressurized. Characterized the piston 13 is displaced against the force of the return spring 28 and thereby the adjusting lever 23 is rotated about the axis of rotation 27, which can be detected with the angle sensor 26. By setting

Intermediate states, the piston 13 with a desired

Move speed and in a desired position to adjust the variable turbine geometry accordingly. The control of the valve 18 is advantageously carried out by an engine control unit, in particular by means of a pulse-width modulation / control depending on the feedback of the first position of the actuator by the angle sensor 26. Alternatively or in addition to the angle sensor 26 may also for this purpose Displacement sensor 30 is provided and assigned to the piston 13. In the present case, the distance measuring sensor 30 is shown in dashed lines.

As shown in Figure 1, the hydraulic components, so the

Hydraulic cylinder 1 1 and the valve 18 expediently in the

Integrated turbine housing of the exhaust gas turbocharger 1, since there is the lubrication and cooling supply of the exhaust gas turbocharger. The individual components can be realized as complete screw - in parts, where they are independent of the exhaust gas turbocharger manufacturer with standardized fitting geometries in the

Exhaust gas turbocharger housing can be used.

Figure 3 shows another embodiment of the actuator 9, wherein from the preceding figures already known elements with the same

Reference numerals are provided so that insofar as to the above

Description is referenced. In the following, the differences should be dealt with essentially.

In contrast to the embodiment according to Figure 2, the valve 18 is formed as a 2/2-way proportional valve in the actuator 9 according to Figure 3, which has only two ports 19 and 31. In the first shown

Extremal state, both connections are switched blind. The port 31 is connected via a line 32 to the tank 22 and to the return of the pressure oil supply 10. From the line 32 goes one

Connecting line 33 which is connected to the first pressure chamber 16 and a second connecting line 34 which is connected to the second pressure chamber 17. The second connection line 34 is arranged downstream of the first connection line 33 on the line 32 outgoing. Between the junctions of the lines 33, 34 with the line 32, a throttle 35 is provided, so that the output 31 is connected directly to the first pressure chamber 16 and via the throttle 35 to the second pressure chamber 17 and to the tank 22. In the second extreme state of the valve 18 are the

Ports 19 and 31 connected to each other.

In the illustrated Extremalzustand of the valve 18, the pressure chambers 16 and 17 are depressurized, so that the piston 13 is urged by the return spring 28 in its initial position, which also represents a return position becomes. By driving the valve 18 so that this in its second

Extremalzustand passes, the first pressure chamber 16 directly with the

Pressure oil supply 10 connected. Due to the throttle 35 ensures that the resulting pressure in the pressure chamber 16 is greater than that in the pressure chamber 17, which is also indirectly connected by the throttle 35 with the pressure oil supply 10. Thereby, the piston 13 is moved against the force of the return spring 28, and the adjusting lever 23 of the adjusting device 8 adjusted for adjusting the variable turbine geometry. According to the embodiment described above, the movement speed of the piston and / or the end position of the piston and thus the pivotal position of the actuating lever 23 can also be determined here by adjusting intermediate states of the valve 18.

Instead of actuating the variable turbine geometry, it is also conceivable to connect the actuator with a so-called waste gate valve for its actuation, which supplies the exhaust gas flow of the turbine 1 according to the position of the piston 13 or wholly or partially passes it.

Overall, therefore, an exhaust gas turbocharger 1 is offered, the actuator 9 is simple and inexpensive to implement due to its compact design, de de actuator 9 is directly connected to the actuator 8 and the space between the turbine 2 and compressor 3 used for the adjusting device 8 and the actuator 9 can be. Preferably, a heat shield 36 is provided which thermally decouples at least the valve 18 and its actuator from the turbine 2.

Claims

Exhaust gas turbocharger (1), in particular for a motor vehicle, having a turbine (2) which can be driven by an exhaust gas stream and which has a pressurized oil supply (10) with lubricant for lubricating movable parts and a

Adjusting device (8) for influencing the exhaust gas flow, wherein the adjusting device (8) is associated with an actuator (9), characterized

in that the actuating drive (9) has a hydraulic cylinder (11) operatively connected to the adjusting device (8), which is connected to the

Pressure oil supply (10) by an actuatable valve (18)

operatively connected / operably connected.

Exhaust gas turbocharger according to claim 1, characterized in that the hydraulic cylinder (1 1) a cylinder tube (12) having an axially therein

slidably mounted piston (13), which together form at least one pressure chamber (16,17), wherein the at least one pressure chamber (16,17) is connected to the valve (18).

Exhaust gas turbocharger according to claim 2, characterized in that the piston (13) is associated with at least one return spring (28).

Exhaust gas turbocharger according to one of claims 2 and 3, characterized

characterized in that the piston (13) with the adjusting device (8), in particular with an adjusting lever (23) of the adjusting device (8), is hingedly connected.

Exhaust gas turbocharger according to claim 4, characterized in that the piston (13) with the adjusting lever (23) is articulated by a slot guide.

Exhaust gas turbocharger according to one of the preceding claims, characterized in that the valve (18) is designed as a 3/2-way valve, with the at least one pressure chamber (16), with the pressure oil supply (10) and connected to a lubricant collecting / storing tank (22).

7. Exhaust gas turbocharger according to one of claims 1 to 6, characterized

characterized in that the valve (18) is designed as a 2/2-way valve.

8. Exhaust gas turbocharger according to one of the preceding claims, characterized in that the hydraulic cylinder (1 1) has two pressure chambers (16,17), wherein the valve (18) through an output (31) with one of the pressure chambers (16,17) directly and to the other pressure chamber (17,16) and the tank (22) through a throttle (35) is connected.

9. Exhaust gas turbocharger according to one of the preceding claims, characterized in that the valve (18) is designed as a proportional valve.

10. The exhaust gas turbocharger according to one of the preceding claims, characterized in that the actuator (9) between the turbine (2) and a by the turbine (2) drivable compressor (3) of the

Exhaust gas turbocharger (1) is arranged.