Verfahren zum Steuern einer Motorbremsvorrichtung sowie Motorbremsvorrichtung

The present invention relates to a method for controlling an engine retarder braking system for an internal combustion engine in motor vehicles, in particular commercial vehicles, according to the preamble of claim 1, an engine retarder braking system according to the preamble of claim 9 and a vehicle according to claim 14.

(Diesel) internal combustion engines in commercial vehicles in particular in air compressing it is known, to generate a back pressure during deceleration by an airbrake in the exhaust system, the work causes an effective engine braking, by the pistons of the internal combustion engine in the exhaust stroke (outlet valves open) against this back pressure.

To are opened to provide for such engine retarder braking system is known to increase the action of a clearly superimposed on, for example, from DE 10 2008,061,412 A1, additionally a decompression brake, wherein the exhaust valves for regular also in the compression stroke after the valve actuation four-cycle principle partially. The additional braking effect is produced here by the throttled deflation of the combustion air into the exhaust system.

For a exhauststeereddecompression brake the valve control is the exhaust valves so designed that the exhaust valves by the exhaust-gas back pressure in the closed (so called valve-jump ) and selectively irregularly Open airbrake this until the next regular valve opening are held open by a mechanism. The decompression brake is supplied from or will be triggered to depend on the insertion of the exhaust-gas back pressure on this.

The object of the invention is, to propose a method and an engine retarder braking system, by means of which a variable engine braking power can be regulated selectively and precisely controllable or at a supercharged combustion engine.

The solve this problem with the features of the independent claims can. Advantageous additional developments of the invention are subject matter of the subordinate claims.

According to claim 1 is a method for controlling an engine retarder braking system for an internal combustion engine in motor vehicles, in particular commercial vehicles, wherein the engine braking mode an intake system, an exhaust system, Austria AG internal-combustion engine-lateral gas-MAN truck & bus ".

_AOE280A2AO> [...][...][...]7ΐθ[...]. [...][...]. [...]…. :

3.4178 AT

09 DECEMBER 2014

shuttle valves (preferably in the four-cycle principle controlled gas exchange valves), in the exhaust system and the intake system by means of at least one a exhaust gas turbosupercharge integrated turbocharger and an engine brake device has, wherein the at least one exhaust valve of the gas exchange valves affecting a Engine braking system, and/or the exhaust gas back-pressure dependent gas-steered in particular, arranged in the exhaust system and a decompression brake, the exhaust gas has back pressure-end airbrake. according to invention is proposed that the requested braking torque as a function of the boost pressure of the exhaust gas turbocharger and engine-brakepray-lift in the upstream of the the exhaust gas back-pressure, preferably arranged upstream of a combustion gas turbine of the exhaust gas turbocharger, airbrake is regulated. It has become known that the exhaust gas back-pressure as soft controlled variable for selectively activating the decompression brake via the supercharging pressure of a turbocharged engine due to the varying pressure conditions is not sufficient, for a targeted insertion or. Controlling the braking power in the braking operation of each requested decompression brake to ensure or respectively of the. Only the linking of back pressure is a reliable controlled variable with the currently present, constitute decompression brake to a precisely controlling the supercharging pressure.

In an advantageous specific refinement of the invention it is proposed that a differential pressure (PL) and at least the manifold pressure as controlled variables are used (PD), wherein the differential pressure from the back pressure (Pa) and the charge pressure (PD) (PL) than Pa-PL = PD is formed. gas pressure-steereddecompression brake not directly As the mechanism of the exhaust gas back-pressure, but by the differential pressure between back pressure (Pa) and manifold pressure (PL) is a function, it is possible with the arrangements according to the invention in an advantageous manner, a precise control of the different brake performance requirements ensure decompression brake over the entire operating range of the engine brake device including.

Therefore, in an advantageous design of the control parameter in a first phase the braking torque with only controlled airbrake, in a transitional phase with a maximum possible braking power decompression brake and in an end phase-activated as decompression brake and the airbrake be regulated via the.

Continue with, a rising boost pressure for a defined differential pressure also in the braking operation of the exhaust gas back-pressure Pa by an alternative adjustment [...] defined-MAN truck & bus Austria AG

3.4178 AT

09 DECEMBER 2014

[...], progressively closing the, preferably arranged upstream of a combustion gas turbine of the exhaust gas turbocharger, airbrake be increased. Also the desired value can be calculated via a characteristic diagram of the supercharging pressure is clamped over the rotational speed of the internal combustion engine and the required engine brake torque.

The desired value of the differential pressure across a favourable main characteristic diagram Furthermore it with control technology is clamped over the rotational speed of the internal combustion engine and the [...], and further via a sinking characteristic diagram, engine brake requirement is spanned over the rotational speed of the internal combustion engine and the, are identified. The main characteristic diagram[...] is advantageously a function of the type, as may be necessary with a rising boost pressure also a rising differential pressure, so as to cause a gas pressure-steered valve opening. On partial brake torque requirementssinking characteristic diagram has the task also to reduce the differential pressure in the.

differential pressure desired valuedifferential pressure actual value We will also see the the position of the as a function of the specifically engine air brake adjusted and preferably.

Finally, it can be advantageous, when at a engine braking load printing desired value about the determined via a regulating element is adjusted to the combustion gas turbine a and influenced load printing actual value, which in turn, in co-operation with the engine braking power or the use of targeted decompression brakedifferential pressure value PD the requested. The control element on the exhaust gas turbocharger can in a manner known per se a bypass valve and/or a flow guiding element of an exhaust gas turbocharger (Waste Gate), in particular a flow guiding element an exhaust turbine with variable turbine geometry be. Optionally can also be an advantage in the air intake system of the internal combustion engine provided for the actuation of a throttle valve.

For a according to the invention is provided in engine retarding systems, the airbrake in the exhaust system and the manifold pressure in the intake system of the internal combustion engine that in the braking operation by the requested braking power via a via a dependent Load pressure regulator and, back pressure and boost pressure are controlled from a differential pressure forming differential pressure regulator. This arise advantages described above in connection with the process control according to the invention already.

Even in which the invention is in turn preferably upstream of a combustion gas turbine of the exhaust gas turbocharger arranged the airbrake engine retarder braking system, highly MAN truck ….….…. ** ** & bus Austria ACT * preferably ** …. * *.

3.4178 AT [...]….[...][...]….[...][...]….[...]

09 DECEMBER 2014

disposed immediately upstream and adjacent the combustion gas turbine, and thus forms a (positive) affecting the gas biasing flow guidance flap from the combustion gas turbine. This it is possible almost without structural additional cost, the inlet manifold pressure for the raise and thus strongly in the braking operation of the braking power necessary to increase mass flow rate in the internal combustion engine can be achieved. The airbrake thus fulfills several functions simultaneously: assist in ensuring preferably regulated for a sufficient exhaust gas back-pressure and, in addition, similar to the function of a regulating flap in exhaust turbines with variable turbine geometry for an advantageous flow against the turbine at reduced exhaust throughput and lower waste gas enthalpy. In practical terms, the upstream of the exhaust turbine (preferably immediately upstream and adjacent the combustion gas turbine) arranged downstream of the exhaust turbine, as opposed to an airbrake a higher pressure drop on the exhaust turbine arranged airbrake, whereby, due to the higher mass and volume flow through the exhaust turbine then possible, the manifold pressure and the exhaust-gas back pressure and thus also the engine braking power can be substantially increased without thermal overloading of the internal combustion engine can be significantly increased on operator-safe manner. This is achieved via the pressure drop of the upstream chamber airbrake By a lesser load of said gas turbine at the same back pressure, what leads thus with increase of back pressure to the desired higher load of said gas turbine without increasing the braking power.

Particularly is preferably provided here that the airbrake upstream and outside, preferably immediately upstream of and outside, a turbine casing of a combustion gas turbine of the exhaust gas turbocharger is disposed (and hence upstream of an flowing in channelturbine case-lateral ). By the arrangement of the at least one upstream flowing in channel the combustion gas turbine and thus outside a turbine casing or the loss of a airbrake this forms a component of the exhaust turbine, whereby a positioning of the airbrake assembly-easy results with increased constructive degrees of freedom. In particular, here then structural interventions in the combustion gas turbine and need not be a multiplicity of different turbines for different model ranges avoided are kept in stock. Particularly preferred concrete first embodiment the turbine can, in accordance with a pilot, in particular a turbine housing of the exhaust turbine, here then with a, via at least one, preferably over several, cylinders of the internal combustion engine with exhaust gas be acted upon fluidically coupled exhaust manifold, wherein between the exhaust turbine and the exhaust manifold, in particular between a turbine housing of the exhaust turbine and the exhaust manifold, and thus immediately upstream and outside of a turbine casing of said gas turbine is capable of obstructing the airbrake having a separate structural unit, with both the turbine casing and the exhaust manifold is solid the connected. According to a second concrete embodiment variant, provided is particularly compact and advantageously structurally that the combustion gas turbine or directly to a via at least one of the exhaust gas turbocharger a exhaust-gas turbine housing, preferably over several, cylinders of the internal combustion engine with exhaust gas powered exhaust manifold is grown, wherein in the region of the exhaust manifold and thus immediately upstream the airbrake and is arranged outside a turbine casing of said gas turbine.

According to a particularly preferred embodiment the boost pressure is also a control member provided in the intake system in which maximum. The the boost pressure in the intake system provided on the exhaust turbine of the exhaust gas turbocharger for example, a control member can influences bypass valve and/or a flow guiding element an exhaust turbine, an exhaust turbine with variable turbine geometry in particular a flow guiding element, and/or a throttle valve in the intake system of the internal combustion engine be.

Finally, the reference values can be stored in families differential pressure automatic controllerload pressure control valve and/or of the the, the function at least from the rotational speed of the internal combustion engine, and pressure values of the boost pressure in the induction system and from the brake power demand is of back pressure in the exhaust system of the internal combustion engine are derived.

Although the invention above has been explained in connection with an airbrake always, this term is to be understood in a wide and broad sense, "airbrake" explicitly and not only limited in a swingable flap arrangement. By the term "airbrake" So, provided that this does not otherwise is explained, expressly also any other suitable and/or non-pivoting throttle devices, such as slide or rotary valve, be comprised.

Regarding which varies with the invention and the advantages it is referred to the process control according to the invention previously occupied by one vehicle.

One embodiment of the invention is with respect to the pendant, said more about schematic drawing. It show:

MAN truck & bus Austria AC? *..

3.4178 AT ** *"

09 DECEMBER 2014

Fig. more sketchily in only 1, simplified representation an internal combustion engine for a commercial vehicle with an air inlet system, an exhaust system, a turbocharger and an engine retarder braking system with a gas controlled decompression brake and an airbrake upstream of the exhaust turbine, wherein said means through an electronic engine control unit and a differential pressure control device are controlled with a Load pressure regulator in the braking operation;

A simplified block diagram of the regulation of the engine retarder braking system 1 2 Fig. with the Load pressure regulator and the differential pressure regulator for alternative adjustment Fig. of a defined back pressure;

Fig. 2 3 a chart on the arrangements of braking power of the internal combustion engine through the speed controllable or in-adjustable Fig.;

Fig. load printing desired value 4 a schematic representation of the formation of the in the Load pressure regulator; and

Fig. 5 a further, schematic representation of the formation of the differential pressure regulator for controlling the engine brake device according to the 1 and differential pressure desired value Fig. in the 2 .

1 only sketchily an internal combustion engine 1 is in the Fig. (for example, a six-cylinder-diesel internal combustion engine) in particular for a commercial vehicle represented, with an air inlet system and an exhaust system 3 2 (unless described conventional construction). In the intake manifold 4 of the intake system may optionally be provided a throttle valve 2 5.

The exhaust system connected to the combustion chambers of the internal combustion engine 3 has a 6 to 1 exhaust manifold, of a turbo charger 7 is connected indirectly or directly to the exhaust turbine 8. The Exhaust gas turbine drives in a known manner a compressor 8 to 9, the intake manifold 4 is connected via a line 10, in turn, promotes and of combustion air under a defined with the boost pressure PL to the combustion chambers of the internal combustion engine 1. Via the exhaust manifold 8 and the exhaust turbine 6 is exhaust gas flowing out The via an exhaust discharged 11 further. The further lines 2 and 3 of the internal combustion engine 1 in the motor vehicle of the intake system are not shown of the exhaust system.

MAN truck & bus Austria AG

3.4178 AT

09 DECEMBER 2014

f | [...] ;

As (not shown) on the internal combustion engine 1 a faces decompression brake engine retarder braking system, the acts on the gas exchange valves or the exhaust valves of the internal combustion engine 1. 8 provided upstream of the exhaust turbine 12 is also an airbrake, by means of which a defined back pressure Pa can be generated.

The decompression brakegas-steered on the increased exhaust-gas back pressure can in known manner be initiated Pa wherein at least partially enclosed airbrake 12, "flutter" or " valve-jump" in which is selectively triggered a (for example, 10 2008,061,412 A1 DE) the exhaust valves.

Regarding exhauststeereddecompression brake is cited in the alternative to said detailed execution of the publications.

In the intake manifold 13 is arranged a further 4 load pressure sensor, by means of which the boost pressure PL detected and 15 is fed via a signal line 14 to a more descriptive engine control unit. Also the back pressure in the exhaust manifold 12 is 6 a upstream of the airbrake Pa measuring pressure sensor 16 used, whose values are also guided via a signal line 14 to the control device.

Also the controller 14 is upon initiation of a signal corresponding to a supplied in the coasting mode of the commercial vehicle and a load signal α B engine braking. The signal B engine brake management (not) is represented by means of a a variable engine braking power requesting delivered.

The controller 14 controls a bypass valve 7 and an exhaust gas recirculation valve 17 on the exhaust turbine 8 of the exhaust gas turbocharger 2 and 3 the exhaust system 18 in a conduit placed between the intake system 19 is based on specifics on the engine power and exhaust emissions of the internal combustion engine 1 to operatingspecific.

The electronic control unit 1 in addition to the known functions in the fired driving operation of the internal combustion engine 14 is modified so that it, if a thrust operation, and the presence of an the airbrake engine brake signal B 12 to a greater or lesser extent for insertion takes place after a defined back pressure Pa closes and further controls the boost pressure PL.

14 in the controller 20 are (Fig. 2) a Load pressure regulator this simplified terms and 21 provided a differential pressure regulator, in the braking operation of the braking power by MAN truck & bus Austria ACT * B.

3.4178 AT

09 DECEMBER 2014

Driving of the airbrake 12 and of the control members (bypass valve 17 for reducing the boost pressure PL and/or a flow guidance flap for increasing the boost pressure and/or the throttle valve 2 in the intake system 5) determine.

The Fig. load printing desired value formation 4 shows schematically a 20' in conjunction with the here not further illustrated is preferably indicated via a characteristic diagram 20. Here Load pressure regulator 20a (only), which via the rotational speed n of the internal combustion engine and the required braking torque is spanned B, the load printing desired value determined. By control interferenceload printing actual value PL on one or more of said control members is adjusted the.

The Fig. differential pressure desired value formation 5 shows a 21' in conjunction with the here not further illustrated differential pressure regulator 20, in which two characteristic maps 21a preferably, 21b are provided, to form of the differential pressure (in terms of control or electronically) are linked mathematically PD.

As in Fig. 5 represented is here main characteristic diagram 21b via the, spanned over the rotational speed n and the load printing actual value PL, a differential pressure desired value formed. Furthermore, 21a via the sinking characteristic diagram, spanned over the rotational speed n and the brake torque requirement B, wherein the differential pressure over defined factors reduced partial brake torque requirements PD.

By using the thus formed pressure values PL and PD it is possible, the relevant back pressure for the engine braking power Pa precise such a manner that a lower curve above the engine speed n as in 3 Fig. represented decompression brake 22 for lesser brake power of a not activated, a central curve 23 for a transition region 24 and an upper curve decompression brake -activated as the greatest possible engine braking power can be selectively controlled or adjusted for, as well as, of course, also intermediate regions between the individual curves can be adjusted or selectively controlled. The lowermost curve constitute 25 is here the drag output, with which the internal combustion engine when the latter is completely opened is towed airbrake.

From the Pa load printing actual value PL shall ensure target exhaust counter-pressure The dependence of that the differential pressure is increased along with an increasing charge pressure PL also PD, whereby the [...]gas-steered valve opening the exhaust valves is ensured. Also the transition region is of only 12 to better manageable decompression brakeexhaust back pressure on the airbrake in addition, the, wherein the different pressure conditions in the gas change of the internal combustion engine 1 are taken into account in the braking operation of improved.

The charge pressure PL in the braking operation of the control members for alternative adjustment of the function of the by B may load printing actual value reduced braking power requested (for example, in the region of the curve 22 in Fig. 3) or increased (for example, curve 3 24 the Fig.) be. These it has been mentioned, as previously, by driving the throttle valve 5 in the suction system 2 reaches and/or of the bypass valve 7 and/or 17 on the exhaust gas turbocharger for example, by driving a flow guidance flap upstream of the exhaust turbine 12 also in conjunction with a the airbrake 8. Optionally could flow guidance flap of a turbo charger 7 with variable turbine geometry are used.

The invention is not limited to the depicted embodiment. With a multi-stage turbocompressor 1 could also include, for example, the internal combustion engine 7 be constructed with two exhaust gas turbochargers arranged one behind the other, one of which may be connected as a high pressure stage and the second as a low-pressure stage.

Truck & bus Austria AG * *..

_AOE280A2AO> [...][...]

_AOE280A2AO> [...][...]

AT * _AOE280A2AO> ' **

: Π [...] :

MAN truck …. * *.* * & bus Austria AG.

_AOE280A2AO> [...][...][...]

_AOE280A2AO> [...][...][...][...]

_AOE280A2AO> " [...][...][...]

3.4178 AT ** **

09 DECEMBER 2014