DE102012207266A1 - Adjustment arrangement for adjusting boost pressure in combustion engine for vehicle, has cooling device that is connected in series with control valve for cooling the exhaust gas flowing through valve - Google Patents

Abstract

The adjustment arrangement has a primary control valve (36) for bridging an exhaust turbine (22) of a turbo supercharger (10). A cooling device (30) is connected in series with the primary valve for cooling the exhaust gas (34) flowing through the primary valve. A secondary valve (38) is located parallel to the first valve and is connected with the cooling device. Independent claims are included for the following: (1) an exhaust system; (2) a combustion engine; (3) a method for adjusting boost pressure in combustion engine; and (4) a control device.

Description

Technical area

The invention generally relates to a control circuit and a method for regulating boost pressures in internal combustion engines, in particular of boost pressures in internal combustion engines with a charging device.

State of the art

Boost pressures in internal combustion engines are generated by superchargers, so-called turbochargers, in particular exhaust gas-driven turbochargers, and serve to increase the performance of piston engines by increasing the mixture throughput per power stroke. For this purpose, the internal combustion engine in its intake tract to a compressor which is driven by an exhaust gas turbine in its exhaust system. The turbocharger thus uses the energy of the exhaust gases of the internal combustion engine.

Such a combustion engine with a turbocharger is from the DE 102 41 884 A1 known. The disclosed therein internal combustion engine has for wastegate control a wastegate channel with a valve closing the wastegate channel to pass exhaust gas flowing through the exhaust system controlled by the exhaust gas turbine.

Disclosure of the invention

According to the invention an arrangement for adjusting a boost pressure in an internal combustion engine according to claim 1, and an exhaust system, an internal combustion engine, a method for adjusting a boost pressure and a control device according to the dependent claims is provided.

• – ein als Stellglied ausgebildetes Ventil zum Überbrücken einer Abgasturbine des Turboladers; und
• – eine Kühlvorrichtung in Reihe zum Ventil zum Kühlen eines das Ventil durchströmenden Abgases.

According to a first aspect, there is provided an arrangement for adjusting a boost pressure in an internal combustion engine with a turbocharger, comprising:

• - Designed as an actuator valve for bypassing an exhaust gas turbine of the turbocharger; and
• - A cooling device in series with the valve for cooling an exhaust gas flowing through the valve.

The above arrangement may particularly preferably be a control loop which adjusts the boost pressure in the internal combustion engine with the turbocharger by regulating the boost pressure.

The invention is based on the consideration that the wastegate duct in the known boost pressure control directs the hot exhaust gas from an internal combustion engine directly past the exhaust gas turbine into, for example, a catalyst. The catalyst serves for the complete combustion of unburned fuel components in the exhaust gas.

The invention is further based on the consideration that the materials of the catalyst are very expensive if they must be resistant to the high temperatures of the hot exhaust gas. Therefore, when using the known boost pressure control with the exhaust gas turbine bridging wastegate channel a costly catalyst is necessary, especially when operating with gas and diesel internal combustion engines, in which the temperatures of the exhaust gas are relatively high.

In order to lower the temperature of the exhaust gas conducted past the exhaust gas turbine, the invention therefore proposes to provide a cooling device in the wastegate duct, which cools the exhaust gas conducted past the exhaust gas turbine and thus exposes the catalyst to less high temperatures. In this way, the catalyst of less temperature-resistant and thus generally cheaper materials can be constructed, which reduces the cost of production of a catalytic converter and the turbocharger with the wastegate channel comprehensive internal combustion engine.

By the specified arrangement, the exhaust gas temperature can be reduced in a combustion engine in an internal combustion engine in a catalytic converter of the internal combustion engine, so that it is exposed to less high temperatures and can be constructed from less temperature-resistant and thus costly materials. The specified arrangement can thus reduce the production costs of an internal combustion engine without sacrificing quality.

In a further development, the specified arrangement comprises a further valve connected in parallel to the valve and to the cooling device. The further, parallel-connected valve thus provides a further wastegate channel, which can be equipped without a cooling device. In this further wastegate channel, the path bridging the exhaust gas turbine can be minimized, so that in the event of an excessively high boost pressure, the specified arrangement can react immediately, in particular if the specified arrangement is designed as a control loop. The wastegate channel with the cooling device, which reacts relatively slowly due to its longer distance, can then be switched to the other Wastegatekanal, whereby the specified arrangement designed as a control loop maximum dynamics can be imparted.

The arrangement can be constructed from the two valves in any way. If the arrangement is constructed as a control loop, then both valves can act as actuators in a cascaded control be constructed, with a lower control loop is superimposed with a valve another sub-control circuit with the other valve. Alternatively, in the control loop, the two subregions may be connected in parallel with the valves. Also, both valves can control either the same controlled variable, such as the pressure or the temperature of the exhaust gas in the exhaust duct or different control variables.

According to a further aspect, an exhaust system for an internal combustion engine with a turbocharger is provided, which comprises an exhaust gas turbine of the turbocharger and a specified arrangement, wherein the valve bridges the exhaust gas turbine of the turbocharger.

In another aspect, an internal combustion engine is provided including an intake tract for aspirating a combustible fuel mixture and the above exhaust system.

In a further development, the specified internal combustion engine comprises an exhaust gas recirculation system for returning at least part of the exhaust gas from the exhaust gas system into the intake system. The exhaust gas recirculation can be used to reduce the emission of nitrogen oxides, which can occur during the combustion of fuel in known internal combustion engines, such as gasoline engines and diesel engines. For the highest possible maximum power, the proportion of exhaust gas recirculated into the intake tract should be as low as possible and the proportion of fresh air should be as large as possible.

According to a further embodiment, at least a part of a channel with the valve and the cooling device of the specified arrangement can be passed through at least part of the exhaust gas recirculation. In this way, an exhaust gas flow conducted into the intake tract by the exhaust gas recirculation can be further reduced, since now part of the exhaust gas flowing through the exhaust gas recirculation is used as exhaust gas to be led past the exhaust gas turbine. In this way, the maximum power of the exhaust gas recirculation is increased in the above manner.

In a particular embodiment, the cooling device of the wastegate channel of the specified control loop can be part of the exhaust gas recirculation. The further development is based on the consideration that the cooling device could be constructed, for example, from an evaporator, which evaporates additional fuel and cools the exhaust gas conducted past the exhaust gas turbine with the evaporative cooling. By using the cooling device in the exhaust gas recirculation channel for cooling the exhaust gas passed past the exhaust gas, no additional cooling device needs to be provided for the technical implementation of the specified arrangement in an internal combustion engine to build the specified arrangement, which further reduces the cost of manufacturing the internal combustion engine.

In another aspect, a vehicle may be provided that includes the above internal combustion engine for propulsion thereof.

In another aspect, there is provided a method of adjusting boost in an internal combustion engine having a turbocharger comprising the steps of bypassing an exhaust turbine of the turbocharger with a valve and cooling exhaust gas flowing through the valve.

According to a development, the specified method may include the step of exhausting the cooled exhaust gas from an exhaust gas recirculation, which connects the exhaust system with an intake tract of the internal combustion engine, which increases the maximum exhaust gas recirculation performance, as already mentioned.

According to another aspect, there is provided a control device configured to perform the above method.

In a development, the control device has a memory and a processor. The specified method is stored in the form of a computer program in the memory and the processor is provided for carrying out the method when the computer program is loaded from the memory into the processor.

Brief description of the drawings

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 a structural representation of an internal combustion engine; and

2 a structural representation of a control loop in the internal combustion engine of 1 ,

Description of embodiments

In the figures, like elements are given the same reference numerals and described only once.

It is referring to 1 taken, which is a structural representation of an internal combustion engine 2 shows. The internal combustion engine 2 has an intake tract 4 for intake of fresh air 6 on. The intake tract 4 is through the compressor 8th a turbocharger 10 guided. The from the compressor 8th exiting compressed fresh air 12 will be over one throttle 14 a combustion chamber 16 fed, the compressed fresh air 12 previously in a manner not shown fuel to combustion in the combustion chamber 16 is added.

In the combustion chamber 16 become the compressed fresh air 12 and the fuel to an exhaust 18 burned that over an exhaust system 20 from the internal combustion engine 2 is ejected. This is the exhaust system 20 over the turbine 22 of the turbocharger 10 led the compressor 8th based on the kinetic energy of the exhaust gas 18 drives. That from the turbine 22 exiting exhaust 18 is through a catalyst 24 directed, in a manner known to those skilled in the art for complete combustion of the exhaust gas 18 is provided so that no fuel residues in the exhaust gas 18 remain.

The exhaust system 20 and the intake tract 4 are via an exhaust gas recirculation 26 connected together, so a part 28 the exhaust gas 18 back to the intake system 4 can be returned. In the exhaust gas recirculation 26 is a cooling device 30 arranged, which is the recirculated exhaust gas 28 cools. Via an exhaust gas recirculation valve 32 can the amount of exhaust gas recirculation 26 recirculated exhaust gas 28 be set.

From the perspective of the exhaust system 20 is in front of the exhaust gas recirculation valve 32 a part 34 the recirculated but through the cooling device 30 cooled exhaust gas 28 via a first wastegate valve 36 called valve on the turbine 22 over in the catalyst 24 directed.

A second wastegate valve 38 is parallel to the first wastegate valve 36 and to the cooler 30 arranged, which is another part 40 from the combustion chamber 16 exiting exhaust gas 18 at the turbine 22 over in the catalyst 24 passes. In front of the catalyst 24 Thus, the exiting the combustion chamber exhaust gas 18 passing through the first wastegate valve 36 flowing exhaust gas 34 and that through the second wastegate valve 38 flowing exhaust gas 40 to one in the catalyst 24 entering exhaust 41 merged.

Compared with that through the second wastegate valve 38 directed exhaust 40 that's through the first wastegate valve 36 directed exhaust 34 cooler, as it is the cooling device 30 has gone through.

A control device 42 which, for example, as a motor control 42 may be formed in a vehicle, not shown, is to control the throttle 14 , the exhaust gas recirculation valve 32 and the wastegate valves 36 . 38 intended. On some of the control signals of the control device 42 will be part of the 2 discussed in more detail.

Through the wastegate valves 36 . 38 is primarily a boost pressure of the compressed fresh air 12 and thus of the combustion chamber 16 exiting exhaust gas 18 regulated, as that from the combustion chamber 16 exiting exhaust gas 18 the turbine 22 drives, in turn, via the compressor 8th the sucked fresh air 6 compacted. The more out of the combustion chamber 16 exiting exhaust 18 at the turbine via the wastegate valves 36 . 38 is passed, the less it is driven and the lower the compression of the fresh air 6 and thus the boost pressure of the compressed fresh air 12 ,

In 2 is structurally a control loop 44 with the wastegate valves 36 . 38 shown with that in the internal combustion engine 2 of the 1 the charge pressure of the compressed fresh air 12 can be adjusted.

The control loop 44 is in a temperature control loop 46 and a boost pressure control loop 48 split, both the internal combustion engine 2 set as a controlled system.

As an actuator has the temperature control circuit 46 the first wastegate valve 36 while the boost pressure control loop 48 as an actuator, the second wastegate valve 38 has.

The temperature control circuit 46 provides based on a set temperature 50 the actual temperature 52 of the catalyst 24 incoming exhaust gas 41 on, while the boost pressure loop 48 based on a target boost pressure 54 the boost pressure 56 the compressed fresh air 12 established.

For setting the set temperature 50 compares the temperature control loop 46 the actual temperature 52 of the catalyst 24 incoming exhaust gas 41 with the set temperature 50 and gives a temperature deviation 58 the actual temperature 52 from the set temperature 50 to a temperature controller 60 off, the temperature deviation 58 in a manner known to those skilled in a temperature controller output signal 62 transforms. The temperature controller 60 is in the present embodiment in the control device 42 integrated so that these as in 1 shown, the temperature controller output signal 62 outputs. With the temperature controller output signal 62 then becomes the first wastegate valve 36 driven. The use of a PID controller as a temperature controller 60 is particularly favorable, since in this the individual controller components, such as the D component can be switched off specifically. Alternatively, however, any other type of regulator for the construction of the temperature control loop 46 be used.

Analogous to the temperature control loop 46 compares the boost pressure control loop 48 for adjusting the boost pressure 56 the compressed fresh air 12 this with the setpoint pressure 54 and gives a corresponding charge pressure deviation 64 to a boost pressure regulator 66 from, which can also be performed as an example as a PID controller. With one out of the boost pressure regulator 66 outputted second boost pressure regulator output signal 68 becomes the second wastegate valve 38 driven. Also the boost pressure regulator 66 is in the present embodiment in the control device 42 integrated so that this is the boost pressure regulator output signal 68 outputs.

The boost pressure control circuit 48 reacts compared to the temperature control loop 46 faster, because the temperature control loop 46 the cooling device 30 which has a dead time in the temperature control loop 46 contributes. This dead time of the actual temperature 52 However, it is not problematic, since the temperature of the components to be protected from overheating in the internal combustion engine 2 such as the catalyst 24 can not rise by leaps and bounds. However, the boost pressure needs 56 much faster on the target boost pressure 54 be corrected because it exceeds a critical limit much faster damage in the internal combustion engine 2 can cause.

The boost pressure control circuit 48 and thus the second wastegate valve 38 are not mandatory. The temperature control circuit 46 can also control the boost pressure 56 with take over when passing through the first wastegate valve 36 flowing exhaust gas 34 introduced dead time is acceptable. Also, the first wastegate valve 36 be used alone for boost pressure control, with its own regulation of the temperature of the catalyst 24 incoming exhaust gas 41 is waived. The cooling of the exhaust gas 41 is controlled as it were. Also, the two control circuits 46 . 48 For example, be cascaded by the temperature controller 60 the target boost pressure 54 or vice versa, by the charge pressure regulator 66 the set temperature 50 outputs.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10241884 A1 [0003]

Claims (10)

Arrangement ( 44 ) for setting a charge pressure ( 56 ) in an internal combustion engine ( 2 ) with a turbocharger ( 10 ) comprising: - a valve designed as an actuator ( 36 ) for bridging an exhaust gas turbine ( 22 ) of the turbocharger ( 10 ) and - a cooling device ( 30 ) in series with the valve ( 36 ) for cooling the valve ( 36 ) by flowing exhaust gas ( 34 ). Arrangement ( 44 ) according to claim 1, which is parallel to the valve ( 36 ) and to the cooling device ( 30 ) switched another valve ( 38 ). Exhaust system ( 20 ) for an internal combustion engine ( 2 ) with a turbocharger ( 10 ) comprising: an exhaust gas turbine ( 22 ) of the turbocharger ( 10 ) and - an arrangement ( 44 ) according to one of claims 1 and 2, wherein the valve ( 36 ) the exhaust gas turbine ( 22 ) of the turbocharger ( 10 ) bridged. Internal combustion engine ( 2 ) further comprising: - an intake tract ( 4 ) for drawing in a combustible fuel mixture; and an exhaust system ( 20 ) according to claim 3. Internal combustion engine ( 2 ) according to claim 4, comprising an exhaust gas recirculation ( 26 ) for returning at least one part ( 28 ) of an exhaust gas ( 18 ) from the exhaust system ( 20 ) in the intake tract ( 4 ). Internal combustion engine ( 2 ) according to claim 5, wherein at least a part of a channel with the valve ( 36 ) and the cooling device ( 30 ) by at least a part of the exhaust gas recirculation ( 26 ). Internal combustion engine ( 2 ) according to claim 5 or 6, wherein the cooling device ( 30 ) Part of the exhaust gas recirculation ( 26 ). Method for setting a charge pressure ( 56 ) in an internal combustion engine ( 2 ) with a turbocharger ( 10 ) comprising the following steps: bridging of an exhaust gas turbine ( 22 ) of the turbocharger ( 10 ) with a positive valve ( 36 ); and - cooling one through the valve ( 36 ) flowing exhaust gas ( 34 ). Method according to claim 8, comprising: - tapping the cooled exhaust gas ( 34 ) from an exhaust gas recirculation ( 26 ), which is an exhaust system ( 20 ) of the internal combustion engine ( 2 ) with an intake tract ( 4 ) of the internal combustion engine ( 2 ) connects. Control device ( 42 ) arranged to perform the method according to claim 8 or 9.

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