EP3450732A1 - Method for braking a combustion engine - Google Patents

Method for braking a combustion engine Download PDF

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Publication number
EP3450732A1
EP3450732A1 EP18189788.5A EP18189788A EP3450732A1 EP 3450732 A1 EP3450732 A1 EP 3450732A1 EP 18189788 A EP18189788 A EP 18189788A EP 3450732 A1 EP3450732 A1 EP 3450732A1
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EP
European Patent Office
Prior art keywords
during
stroke
internal combustion
gas outlet
combustion engine
Prior art date
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Granted
Application number
EP18189788.5A
Other languages
German (de)
French (fr)
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EP3450732B1 (en
Inventor
Thomas Malischewski
Dominik Renner
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MAN Truck and Bus SE
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MAN Truck and Bus SE
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Publication of EP3450732A1 publication Critical patent/EP3450732A1/en
Application granted granted Critical
Publication of EP3450732B1 publication Critical patent/EP3450732B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/04—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation using engine as brake
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
    • F01L13/0036—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
    • F01L13/0042—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction with cams being profiled in axial and radial direction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/06—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking
    • F01L13/065—Compression release engine retarders of the "Jacobs Manufacturing" type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0203—Variable control of intake and exhaust valves
    • F02D13/0215—Variable control of intake and exhaust valves changing the valve timing only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0242—Variable control of the exhaust valves only
    • F02D13/0246—Variable control of the exhaust valves only changing valve lift or valve lift and timing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0242—Variable control of the exhaust valves only
    • F02D13/0249—Variable control of the exhaust valves only changing the valve timing only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0257—Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2760/00—Control of valve gear to facilitate reversing, starting, braking of four stroke engines
    • F01L2760/003—Control of valve gear to facilitate reversing, starting, braking of four stroke engines for switching to compressor action in order to brake
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F02D2041/001—Controlling intake air for engines with variable valve actuation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/101—Engine speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/12—Introducing corrections for particular operating conditions for deceleration

Definitions

  • the invention relates to a method for braking an internal combustion engine and a motor vehicle with a variable valve train for carrying out the method.
  • Such a method describes the DE 39 22 884 A1 in which, in addition to the closing of a stowage flap in the exhaust tract, a decompression effect substantially increasing the engine braking effect is achieved by partially opening the exhaust valves (inlet valves unchanged) by engaging in the valve control of the internal combustion engine in the compression stroke and thus in the cylinder during the intake stroke sucked in air in the exhaust tract decompressed blow off.
  • the exhaust valves are fully open in regular actuation each exhaust stroke, so here almost no decompression effect.
  • Exemplary further methods for braking an internal combustion engine are in the DE 10 2015 016 526 A1 .
  • the present disclosure particularly provides in the DE 10 2013 019 183 A1 disclosed method for controlling the engine braking effect on.
  • the at least one outlet valve is open, optionally with overlapping, in the compression stroke and in the exhaust stroke.
  • the at least one exhaust valve or at least one of the exhaust valves is opened with a defined predetermined and / or compared to a regular valve lift valve lift each in the TDC range of the piston between the compression stroke and the expansion stroke and between the exhaust stroke and the intake stroke.
  • a disadvantage of the from the DE 10 2013 019 183 A1 known methods may be that at low engine speeds due to the compression of the gas in the Ausschiebetakt can lead to unwanted engine excitation, for example, if not all cylinders be operated in engine braking mode. This motor excitation can lead to undesired vibrations in the drive train.
  • the invention is therefore based on the object to provide an improved method for braking an internal combustion engine.
  • the method is suitable for braking an internal combustion engine, in particular a four-stroke internal combustion engine.
  • the method comprises partially opening at least one gas outlet valve of at least one cylinder of the internal combustion engine during a compression stroke of the internal combustion engine.
  • the method comprises holding a partial opening of the at least one gas outlet valve during an expansion stroke of the internal combustion engine following the compression stroke and during an exhaust stroke of the internal combustion engine following the expansion stroke.
  • the method includes closing the partially opened at least one gas outlet valve at the end (in the TDC range) of the exhaust stroke or during an intake stroke of the internal combustion engine following the exhaust stroke.
  • the method makes particularly advantageous use of the gas dynamics of the gas flowing out of the combustion chambers of the internal combustion engine through the gas outlet valve (s).
  • the partial opening of the gas outlet valve during the expansion stroke and the Ausschiebetaktes leads in response to an engine speed of the internal combustion engine to greatly different cylinder pressure curves. This allows different, desirable cylinder pressure curves and thus engine brake effects to be set for different engine speeds.
  • only a compression and decompression in the region of the compression stroke can occur at low speeds. At higher speeds, however, a first compression and a first decompression in the compression stroke and a second compression and a second decompression in Ausschiebetakt may occur.
  • the at least one gas outlet valve may be provided upstream of an exhaust tract of the internal combustion engine.
  • the at least one gas outlet valve is opened so far during the partial opening that at a rotational speed of the internal combustion engine below a limit rotational speed of the internal combustion engine substantially no compression takes place in the respective cylinder during the exhaust stroke.
  • a flow cross-section defined by a valve gap of the at least one partially opened gas outlet valve may be set so that there is substantially no compression below the limit speed and thus engine braking due to compression in the respective cylinder during the exhaust stroke.
  • the flow cross section is sufficient to push out the gas at a relatively low piston speed at a low engine speed substantially without compression in the cylinder through the partially opened gas outlet.
  • the at least one gas outlet valve is opened so far during the partial opening that, at a rotational speed of the internal combustion engine above the limit rotational speed, a compression occurs in the respective cylinder during the exhaust stroke.
  • the flow cross-section defined by the valve gap of the at least one partially opened gas outlet valve may be set to be above the limit speed for compression and thus for engine braking in the respective cylinder during the exhaust stroke. This can be achieved above the limit speed desired at high speeds high engine braking effect.
  • the flow cross-section is dimensioned so that at a relatively high piston speed at a high engine speed, the gas can not be ejected without pressure increase in the cylinder through the partially opened gas outlet valve.
  • the compression increases in each cylinder in Ausschiebetakt with increasing speed of the internal combustion engine above the limit speed.
  • the limit speed is in a range between 1000 U / min and 1700 U / min, in particular in a range between 1200 U / min and 1500 U / min.
  • the limit speed may be selected so that the speed range below the limit speed is the range in which it would come to the above-mentioned adverse motor excitation by compression in Ausschiebetakt.
  • the at least one gas outlet valve is opened during partial opening in a range between 5% and 30% of a maximum valve lift of the at least one gas outlet valve.
  • the at least one gas outlet valve is opened during partial opening in a range between 0.5 mm and 3 mm.
  • a maximum valve lift is in a range between 10 mm and 16 mm.
  • the partial opening of the at least one gas outlet valve begins during the compression stroke in a range between 100 ° CA and 60 ° CA before TDC (top dead center of a piston movement of a piston of the respective cylinder).
  • the gas in the combustion chamber is first compressed and pushed out only at the end of the compression stroke through the partially opening at least one gas outlet valve to achieve a decompression effect in the exhaust system.
  • the closing of the at least one gas outlet valve begins at the end of the exhaust stroke or during the intake stroke in a range between TDC (top dead center of a piston movement of a piston of the respective cylinder) and 30 ° CA to TDC.
  • the gas flowing back from the exhaust tract into the combustion chamber during the expansion stroke can either be directly expelled back into the exhaust tract through the at least partially opened gas outlet valve or, at higher engine speeds, at least partially compressed and only then through the exhaust gas at least one partially opened gas outlet valve are pushed out. At higher speeds, it may thus come in Ausschiebetakt to a further compression of the gas in the combustion chamber with subsequent decompression of the compressed gas in the exhaust system, whereby an engine braking effect of the method is increased.
  • the closing of the at least one gas outlet valve may overlap with an opening of at least one gas inlet valve.
  • a constant valve lift of the at least one is achieved Gas outlet valve held.
  • This is control technology particularly simple, for example, realized with a constant height of a cam of a camshaft.
  • two gas outlet valves are provided per cylinder and only one of the two gas outlet valves is partially opened during the compression stroke, kept open with a partial opening during the expansion stroke and the exhaust stroke and closed at the end of the exhaust stroke or during the intake stroke. Additionally, the other of the two exhaust gas valves may be closed during the compression stroke, the expansion stroke, the exhaust stroke, and the intake stroke.
  • the loads on the associated with the gas outlet valves variable valve train can be reduced because in particular only one of the gas outlet valves per cylinder must be opened against the pressure in the combustion chamber during the compression stroke.
  • the method additionally comprises opening at least one gas inlet valve of the at least one cylinder during an intake stroke and closing the at least one gas inlet valve during the compression stroke, the expansion stroke and the exhaust stroke.
  • the gas inlet valves during engine braking operation of the internal combustion engine can be operated as in normal operation of the internal combustion engine.
  • the operation of the gas inlet valves for the engine braking operation does not have to be switched.
  • the gas inlet valves are used in engine braking operation to direct air from an air supply system of the internal combustion engine during the intake stroke in the combustion chambers.
  • the method may further include closing a damper provided downstream of the at least one gas outlet valve during the compression stroke and / or during the exhaust stroke.
  • the storage flap may preferably be arranged in the exhaust tract.
  • the present invention also relates to a variable valve train for an internal combustion engine.
  • the variable valve train may in particular be designed as a sliding cam system.
  • the variable valve train is configured to perform the method as disclosed herein.
  • the present disclosure also pertains to a motor vehicle, particularly commercial vehicle (eg, bus or truck) having an internal combustion engine having the variable valve train disclosed herein.
  • a motor vehicle particularly commercial vehicle (eg, bus or truck) having an internal combustion engine having the variable valve train disclosed herein.
  • the FIG. 1 shows a cylinder 12 of an internal combustion engine 10.
  • the internal combustion engine 10 is a four-stroke internal combustion engine, in particular a four-stroke diesel engine or a four-stroke gasoline internal combustion engine.
  • the internal combustion engine 10 in a commercial vehicle for example, a truck or a bus, for driving the commercial vehicle comprises.
  • the cylinder 12 has at least one gas inlet valve 14, at least one gas outlet valve 16, a combustion chamber 18 and a piston 20.
  • the at least one gas inlet valve 14 connects the combustion chamber 18 to an air supply system of the internal combustion engine 10 for supplying combustion air into the combustion chamber 18.
  • the at least one gas outlet valve 16 connects the combustion chamber 18 to an exhaust line of the internal combustion engine 10 for exhausting exhaust gases.
  • two gas inlet valves 14 and two gas outlet valves 16 per cylinder 12 and a plurality of cylinders 12 may be provided.
  • the at least one gas outlet valve 16 can be actuated via a variable valve drive 22.
  • the variable valve drive 22 may be formed, for example, as a sliding cam system.
  • the sliding cam system may have at least one cam carrier with at least two cams.
  • the cam carrier can be arranged rotationally fixed and axially displaceable on a camshaft.
  • the at least one gas exchange valve is actuated by various cams of the cam carrier in response to an axial position of the cam carrier. It is also possible that with several gas outlet valves 16 per cylinder 12, the gas outlet valves 16 of the respective cylinder 12 are actuated differently.
  • the piston 20 is reciprocably disposed in the cylinder 12 in a known manner and connected to a crankshaft 24.
  • FIG. 2 is an exemplary control diagram for the operation of the gas inlet valves 14 and the gas outlet valves 16 of FIG. 1 during engine braking operation of the engine 10.
  • a broken line A shows a valve lift of the gas inlet valves 14 in dependence on a crank angle of the crankshaft 24.
  • a dashed curve B shows a valve lift of the gas exhaust valve 16 as a function of the crank angle of the crankshaft 24.
  • a solid curve C shows a cylinder pressure in the combustion chamber 18 in FIG Dependence on a crank angle of the crankshaft 24 at a low engine speed.
  • a dotted curve D shows a cylinder pressure in the combustion chamber 18 in response to a crank angle of the crankshaft 24 at a high engine speed.
  • the curves A to D are plotted against the usual in four-stroke operation 720 ° crank angle (KW), the left axis of the graph indicate the cylinder pressures in bar and the right axis the valve strokes in mm.
  • the gas inlet valves 14 are opened during the engine braking operation as well as in the regular operation during the intake stroke. Over the further control cycle, the gas inlet valves 14 are closed.
  • the gas exhaust valves 16 are controlled unlike in the regular operation (normal operation) in which the gas exhaust valves 16 are opened only during the exhaust stroke.
  • the engine per cylinder 12 may have two exhaust gas valves 16, one of which is kept fully closed during engine braking operation and the other is controlled according to curve B during engine braking operation.
  • the gas exhaust valve 16 becomes about 60 ° CA to 100 ° CA before the upper ignition dead center, that is, the engine exhaust gas. H. before the end of the compression stroke, partially open.
  • the gas outlet valve 16 is then partially kept open during the expansion stroke and the exhaust stroke for approximately 360 ° CA.
  • the partially open gas outlet valve 16 is closed again after the Ausschiebetakt and remains closed until reopening in the compression stroke.
  • the gas outlet valve 16 is only partially opened according to the curve B.
  • the partial opening may correspond to a valve lift of 0.5 mm to 3 mm.
  • a maximum lift (regular stroke) of the gas exhaust valve 16 may be, for example, between about 10 mm for small internal combustion engines 10 and up to about 16 mm for very large internal combustion engines 10 in commercial vehicle construction.
  • the curve C at low rotational speeds of the internal combustion engine 10 to, for example, about 1200 rpm, no compression occurs in the combustion chamber 18 during the exhaust stroke. This is due to the valve gap through the partially opened gas outlet valve 16. This valve gap is sufficient at low velocities of the piston 20 to allow the gas in the combustion chamber 18 to flow from the combustion chamber 18 through the partially opened gas outlet valve 16 without increasing pressure.
  • the curve C relates, for example, to a cylinder pressure curve at an engine speed of the internal combustion engine of approximately 600 rpm.
  • the curve D at high rotational speeds of the internal combustion engine 10 from, for example, 1200 rpm to 1500 rpm, compression occurs in the combustion chamber 18 during the exhaust stroke. Due to the increased engine speed, the piston speed of the piston 20 increases and the volume flow over the partially opened gas outlet valve 16 also increases. The valve gap provided by the partially opened gas outlet valve 16 is no longer sufficient to push out the gas without compression. Instead, there is a second compression before top dead center at the end of Ausschiebetaktes. In the second compression, compression energy is dissipated by the still open gas outlet valve 16 and braking power is generated. In particular, the compression work brakes the piston 20, whereby the internal combustion engine 10 is braked during engine braking operation.
  • the curve D refers to a cylinder pressure history at an engine speed of the engine of about 2600 rpm.
  • a transition between the curves C and D takes place continuously with increasing engine speed of the internal combustion engine 10.
  • the invention thus makes it possible in a particularly advantageous manner that with the same control profile for a gas outlet valve 16 at high rotational speeds of the internal combustion engine 10, a high braking effect is achieved by the double compression-decompression (curve D). At low speeds as well, a (small) braking effect is achieved by the one-time compression-decompression (curve C), whereby motor excitation due to the omission of the second compression-decompression is prevented or at least reduced.
  • the process thus adapts itself to the ambient conditions (the engine speed), so that no additional control intervention from the outside is necessary.
  • the invention is not limited to the preferred embodiments described above. Rather, a variety of variants and modifications is possible, which also make use of the inventive idea and therefore fall within the scope.
  • the invention also claims protection of the subject matter and the features of the subclaims independently of the claims referred to.
  • the features of the subclaims are also independent of all features of independent claim 1 and, for example, independent of the characteristics regarding at least one opening of at least one gas outlet valve during a compression stroke, holding a partial opening of the at least one gas outlet valve during an expansion stroke and / or Ausschiebetaktes and / or Closing the partially open at least one gas outlet valve at the end of Ausschiebetaktes or during an intake stroke of the independent claim 1 disclosed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Valve Device For Special Equipments (AREA)

Abstract

Die Erfindung betrifft ein Verfahren zum Bremsen einer Brennkraftmaschine (10), insbesondere einer Viertakt-Brennkraftmaschine. Das Verfahren weist ein teilweises Öffnen mindestens eines Gasauslassventils (16) mindestens eines Zylinders (12) der Brennkraftmaschine (10) während eines Verdichtungstaktes der Brennkraftmaschine (10) auf. Das Verfahren weist ein Halten einer teilweisen Öffnung des mindestens einen Gasauslassventils (16) während eines an den Verdichtungstakt anschließenden Expansionstaktes der Brennkraftmaschine (10) und während eines an den Expansionstakt anschließenden Ausschiebetaktes der Brennkraftmaschine (10) auf. Das Verfahren weist ein Schließen des teilweise geöffneten mindestens einen Gasauslassventils (16) am Ende des Ausschiebetaktes oder während eines an den Ausschiebetakt anschließenden Ansaugtaktes der Brennkraftmaschine (10) auf. Damit können auf vorteilhafte Weise insbesondere im Bereich des Ausschiebetaktes unterschiedliche, von einer Motordrehzahl abhängige Zylinderdruckverläufe erzielt werden.The invention relates to a method for braking an internal combustion engine (10), in particular a four-stroke internal combustion engine. The method has a partial opening of at least one gas outlet valve (16) of at least one cylinder (12) of the internal combustion engine (10) during a compression stroke of the internal combustion engine (10). The method comprises holding a partial opening of the at least one gas outlet valve (16) during an expansion stroke of the internal combustion engine (10) following the compression stroke and during an exhaust stroke of the internal combustion engine (10) following the expansion stroke. The method includes closing the partially opened at least one gas outlet valve (16) at the end of the exhaust stroke or during an intake stroke of the internal combustion engine (10) following the exhaust stroke. This can be achieved in an advantageous manner, in particular in the field of Ausschiebetaktes different, dependent on an engine speed cylinder pressure curves.

Description

Die Erfindung betrifft ein Verfahren zum Bremsen einer Brennkraftmaschine und ein Kraftfahrzeug mit einem variablen Ventiltrieb zum Ausführen des Verfahrens.The invention relates to a method for braking an internal combustion engine and a motor vehicle with a variable valve train for carrying out the method.

Ein derartiges Verfahren beschreibt die DE 39 22 884 A1 , bei dem im Motorbremsbetrieb neben dem Schließen einer Stauklappe im Abgastrakt eine die Motorbremswirkung wesentlich steigernde Dekompressionswirkung dadurch erzielt wird, dass die Auslassventile (Einlassventile unverändert) durch Eingriff in die Ventilsteuerung der Brennkraftmaschine jeweils im Verdichtungstakt teilweise geöffnet werden und damit die beim Ansaugtakt in den Zylinder eingesaugte Luft in den Abgastrakt dekomprimiert abblasen. Ferner sind die Auslassventile in regulärer Betätigung jeweils beim Ausschubtakt vollständig geöffnet, hier also nahezu ohne Dekompressionswirkung.Such a method describes the DE 39 22 884 A1 in which, in addition to the closing of a stowage flap in the exhaust tract, a decompression effect substantially increasing the engine braking effect is achieved by partially opening the exhaust valves (inlet valves unchanged) by engaging in the valve control of the internal combustion engine in the compression stroke and thus in the cylinder during the intake stroke sucked in air in the exhaust tract decompressed blow off. In addition, the exhaust valves are fully open in regular actuation each exhaust stroke, so here almost no decompression effect.

Beispielhafte weitere Verfahren zum Bremsen einer Brennkraftmaschine sind in der DE 10 2015 016 526 A1 , DE 10 2005 033 163 A1 , der DE 196 49 174 A1 und der US 4,592,319 A offenbart.Exemplary further methods for braking an internal combustion engine are in the DE 10 2015 016 526 A1 . DE 10 2005 033 163 A1 , the DE 196 49 174 A1 and the US 4,592,319 A disclosed.

Die vorliegende Offenbarung bildet insbesondere das in der DE 10 2013 019 183 A1 offenbarte Verfahren zum Steuern der Motorbremswirkung weiter. Im Einzelnen offenbart die DE 10 2013 019 183 A1 ein Verfahren zum Steuern der Motorbremswirkung einer ventilgesteuerten Brennkraftmaschine, insbesondere einer Viertakt-Brennkraftmaschine, für Kraftfahrzeuge, bei dem neben einem Abgasstau in der Abgasleitung durch Schließen einer Stauklappe eine Dekompressionswirkung durch teilweises, insbesondere irreguläres, Öffnen des wenigstens einen Auslassventils je Zylinder der Brennkraftmaschine erzeugt wird. Das wenigstens eine Auslassventil ist, gegebenenfalls mit Überschneidungen, im Verdichtungstakt und im Ausschubtakt geöffnet. Zur Erhöhung der Motorbremswirkung wird das wenigstens eine Auslassventil oder wenigstens eines der Auslassventile mit einem definiert vorgegebenen und/oder gegenüber einem regulären Ventilhub geringerem Ventilhub jeweils im OT-Bereich der Kolben zwischen dem Verdichtungstakt und dem Expansionstakt und zwischen dem Ausschubtakt und dem Ansaugtakt geöffnet.The present disclosure particularly provides in the DE 10 2013 019 183 A1 disclosed method for controlling the engine braking effect on. In detail, the reveals DE 10 2013 019 183 A1 a method for controlling the engine braking effect of a valve-controlled internal combustion engine, in particular a four-stroke internal combustion engine, for motor vehicles, in which in addition to an exhaust gas in the exhaust pipe by closing a damper a decompression effect by partial, in particular irregular, opening the at least one exhaust valve per cylinder of the internal combustion engine is generated , The at least one outlet valve is open, optionally with overlapping, in the compression stroke and in the exhaust stroke. To increase the engine braking effect, the at least one exhaust valve or at least one of the exhaust valves is opened with a defined predetermined and / or compared to a regular valve lift valve lift each in the TDC range of the piston between the compression stroke and the expansion stroke and between the exhaust stroke and the intake stroke.

Nachteilig an dem aus der DE 10 2013 019 183 A1 bekannten Verfahren kann sein, dass es bei niedrigen Motordrehzahlen aufgrund der Komprimierung des Gases im Ausschiebetakt zu einer ungewünschten Motoranregung kommen kann, wenn beispielsweise nicht alle Zylinder im Motorbremsbetrieb betrieben werden. Diese Motoranregung kann zu ungewünschten Schwingungen im Antriebsstrang führen.A disadvantage of the from the DE 10 2013 019 183 A1 known methods may be that at low engine speeds due to the compression of the gas in the Ausschiebetakt can lead to unwanted engine excitation, for example, if not all cylinders be operated in engine braking mode. This motor excitation can lead to undesired vibrations in the drive train.

Der Erfindung liegt somit die Aufgabe zu Grunde, ein verbessertes Verfahren zum Bremsen einer Brennkraftmaschine vorzusehen.The invention is therefore based on the object to provide an improved method for braking an internal combustion engine.

Die Aufgabe wird gelöst durch ein Verfahren und ein Kraftfahrzeug gemäß den unabhängigen Ansprüchen. Vorteilhafte Weiterbildungen sind in den abhängigen Ansprüchen und der Beschreibung angegeben.The object is achieved by a method and a motor vehicle according to the independent claims. Advantageous developments are specified in the dependent claims and the description.

Das Verfahren ist zum Bremsen einer Brennkraftmaschine, insbesondere einer Viertakt-Brennkraftmaschine, geeignet. Das Verfahren weist ein teilweises Öffnen mindestens eines Gasauslassventils mindestens eines Zylinders der Brennkraftmaschine während eines Verdichtungstaktes der Brennkraftmaschine auf. Das Verfahren weist ein Halten einer teilweisen Öffnung des mindestens einen Gasauslassventils während eines an den Verdichtungstakt anschließenden Expansionstaktes der Brennkraftmaschine und während eines an den Expansionstakt anschließenden Ausschiebetaktes der Brennkraftmaschine auf. Das Verfahren weist ein Schließen des teilweise geöffneten mindestens einen Gasauslassventils am Ende (im OT-Bereich) des Ausschiebetaktes oder während eines an den Ausschiebetakt anschließenden Ansaugtaktes der Brennkraftmaschine auf.The method is suitable for braking an internal combustion engine, in particular a four-stroke internal combustion engine. The method comprises partially opening at least one gas outlet valve of at least one cylinder of the internal combustion engine during a compression stroke of the internal combustion engine. The method comprises holding a partial opening of the at least one gas outlet valve during an expansion stroke of the internal combustion engine following the compression stroke and during an exhaust stroke of the internal combustion engine following the expansion stroke. The method includes closing the partially opened at least one gas outlet valve at the end (in the TDC range) of the exhaust stroke or during an intake stroke of the internal combustion engine following the exhaust stroke.

Das Verfahren nutzt auf besonders vorteilhafte Weise die Gasdynamik des aus den Verbrennungskammern der Brennkraftmaschine durch das oder die Gasauslassventile ausströmenden Gases. Die teilweise Öffnung des Gasauslassventils während des Expansionstaktes und des Ausschiebetaktes führt in Abhängigkeit von einer Motordrehzahl der Brennkraftmaschine zu stark unterschiedlichen Zylinderdruckverläufen. Dies ermöglicht, dass für unterschiedliche Motordrehzahlen unterschiedliche, wünschenswerte Zylinderdruckverläufe und somit Motorbremswirkungen einstellbar sind. Insbesondere kann bei niedrigen Drehzahlen nur eine Verdichtung und Dekomprimierung im Bereich des Verdichtungstaktes auftreten. Bei höheren Drehzahlen können hingegen eine erste Verdichtung und eine erste Dekomprimierung im Verdichtungstakt und eine zweite Verdichtung und eine zweite Dekomprimierung im Ausschiebetakt auftreten. Damit kann insbesondere der eingangs genannte Nachteil der ungewünschten Motoranregung bei niedrigen Motordrehzahlen aufgrund einer Verdichtung mit anschließender Dekomprimierung im Ausschiebetakt verhindert werden. Dieser Effekt wird dadurch erzielt, dass durch das teilweise geöffnete Gasauslassventil stets der gleiche Strömungsquerschnitt bereitgestellt wird, die für das Gas zum Ausströmen zur Verfügung stehende Zeit bei niedrigen Motordrehzahlen jedoch größer ist als bei hohen Motordrehzahlen.The method makes particularly advantageous use of the gas dynamics of the gas flowing out of the combustion chambers of the internal combustion engine through the gas outlet valve (s). The partial opening of the gas outlet valve during the expansion stroke and the Ausschiebetaktes leads in response to an engine speed of the internal combustion engine to greatly different cylinder pressure curves. This allows different, desirable cylinder pressure curves and thus engine brake effects to be set for different engine speeds. In particular, only a compression and decompression in the region of the compression stroke can occur at low speeds. At higher speeds, however, a first compression and a first decompression in the compression stroke and a second compression and a second decompression in Ausschiebetakt may occur. This can be prevented in particular by the aforementioned disadvantage of the unwanted engine excitation at low engine speeds due to compression with subsequent decompression in Ausschiebetakt. This effect is achieved by the fact that the partially opened gas outlet always the same flow cross-section however, the time available for the gas to flow out is greater at low engine speeds than at high engine speeds.

Insbesondere kann das mindestens eine Gasauslassventil stromaufwärts von einem Abgastrakt der Brennkraftmaschine vorgesehen sein.In particular, the at least one gas outlet valve may be provided upstream of an exhaust tract of the internal combustion engine.

In einer besonders vorteilhaften Weiterbildung wird das mindestens eine Gasauslassventil beim teilweisen Öffnen so weit geöffnet, dass es bei einer Drehzahl der Brennkraftmaschine unterhalb einer Grenzdrehzahl der Brennkraftmaschine zu im Wesentlichen keiner Verdichtung im jeweiligen Zylinder während des Ausschiebetaktes kommt. Im Einzelnen kann ein Strömungsquerschnitt, der von einem Ventilspalt des mindestens einen teilweise geöffneten Gasauslassventils definiert wird, so eingestellt sein, dass es unterhalb der Grenzdrehzahl zu im Wesentlichen keiner Verdichtung und somit Motorbremswirkung aufgrund der Verdichtung im jeweiligen Zylinder während des Ausschiebetaktes kommt. Mit anderen Worten gesagt, der Strömungsquerschnitt reicht aus, um bei einer vergleichsweise geringen Kolbengeschwindigkeit bei einer kleinen Motordrehzahl das Gas im Wesentlichen ohne Verdichtung im Zylinder durch das teilweise geöffnete Gasauslassventil auszuschieben.In a particularly advantageous development, the at least one gas outlet valve is opened so far during the partial opening that at a rotational speed of the internal combustion engine below a limit rotational speed of the internal combustion engine substantially no compression takes place in the respective cylinder during the exhaust stroke. In detail, a flow cross-section defined by a valve gap of the at least one partially opened gas outlet valve may be set so that there is substantially no compression below the limit speed and thus engine braking due to compression in the respective cylinder during the exhaust stroke. In other words, the flow cross section is sufficient to push out the gas at a relatively low piston speed at a low engine speed substantially without compression in the cylinder through the partially opened gas outlet.

In einer bevorzugten Weiterbildung wird das mindestens eine Gasauslassventil beim teilweisen Öffnen so weit geöffnet, dass es bei einer Drehzahl der Brennkraftmaschine oberhalb der Grenzdrehzahl zu einer Verdichtung im jeweiligen Zylinder während des Ausschiebetaktes kommt. Im Einzelnen kann der Strömungsquerschnitt, der von der Ventilspalt des mindestens einen teilweise geöffneten Gasauslassventils definiert wird, so eingestellt sein, dass es oberhalb der Grenzdrehzahl zu der Verdichtung und somit Motorbremswirkung im jeweiligen Zylinder während des Ausschiebetaktes kommt. Damit kann oberhalb der Grenzdrehzahl die bei hohen Drehzahlen gewünschte hohe Motorbremswirkung erzielt werden. Mit anderen Worten gesagt, der Strömungsquerschnitt ist so bemessen, dass bei einer vergleichsweise hohen Kolbengeschwindigkeit bei einer hohen Motordrehzahl das Gas nicht ohne Druckanstieg im Zylinder durch das teilweise geöffnete Gasauslassventil ausgeschoben werden kann.In a preferred development, the at least one gas outlet valve is opened so far during the partial opening that, at a rotational speed of the internal combustion engine above the limit rotational speed, a compression occurs in the respective cylinder during the exhaust stroke. In detail, the flow cross-section defined by the valve gap of the at least one partially opened gas outlet valve may be set to be above the limit speed for compression and thus for engine braking in the respective cylinder during the exhaust stroke. This can be achieved above the limit speed desired at high speeds high engine braking effect. In other words, the flow cross-section is dimensioned so that at a relatively high piston speed at a high engine speed, the gas can not be ejected without pressure increase in the cylinder through the partially opened gas outlet valve.

In einer Ausführungsvariante nimmt die Verdichtung im jeweiligen Zylinder im Ausschiebetakt bei zunehmender Drehzahl der Brennkraftmaschine oberhalb der Grenzdrehzahl zu.In one embodiment, the compression increases in each cylinder in Ausschiebetakt with increasing speed of the internal combustion engine above the limit speed.

In einer Ausführungsvariante liegt die Grenzdrehzahl in einem Bereich zwischen 1000 U/min und 1700 U/min, insbesondere in einem Bereich zwischen 1200 U/min und 1500 U/min.In one embodiment, the limit speed is in a range between 1000 U / min and 1700 U / min, in particular in a range between 1200 U / min and 1500 U / min.

Insbesondere kann die Grenzdrehzahl so gewählt sein, dass der Drehzahlbereich unterhalb der Grenzdrehzahl derjenige Bereich ist, in dem es zu der oben genannten nachteiligen Motoranregung durch eine Verdichtung im Ausschiebetakt kommen würde.In particular, the limit speed may be selected so that the speed range below the limit speed is the range in which it would come to the above-mentioned adverse motor excitation by compression in Ausschiebetakt.

In einer Ausführungsvariante wird das mindestens eine Gasauslassventil beim teilweisen Öffnen in einem Bereich zwischen 5 % und 30 % eines maximalen Ventilhubs des mindestens einen Gasauslassventils geöffnet. Alternativ oder zusätzlich wird das mindestens eine Gasauslassventil beim teilweisen Öffnen in einem Bereich zwischen 0,5 mm und 3 mm geöffnet.In an embodiment variant, the at least one gas outlet valve is opened during partial opening in a range between 5% and 30% of a maximum valve lift of the at least one gas outlet valve. Alternatively or additionally, the at least one gas outlet valve is opened during partial opening in a range between 0.5 mm and 3 mm.

In einer weiteren Ausführungsvariante liegt ein maximaler Ventilhub in einem Bereich zwischen 10 mm und 16 mm.In a further embodiment, a maximum valve lift is in a range between 10 mm and 16 mm.

In einer Ausführungsform beginnt das teilweise Öffnen des mindestens einen Gasauslassventils während des Verdichtungstaktes in einem Bereich zwischen 100° KW und 60° KW vor OT (oberen Totpunkt einer Kolbenbewegung eines Kolbens des jeweiligen Zylinders). Damit wird das in der Verbrennungskammer befindliche Gas zunächst verdichtet und erst zum Ende des Verdichtungstaktes durch das sich teilweise öffnende mindestens eine Gasauslassventil unter Erzielung einer Dekompressionswirkung in den Abgastrakt ausgeschoben.In one embodiment, the partial opening of the at least one gas outlet valve begins during the compression stroke in a range between 100 ° CA and 60 ° CA before TDC (top dead center of a piston movement of a piston of the respective cylinder). Thus, the gas in the combustion chamber is first compressed and pushed out only at the end of the compression stroke through the partially opening at least one gas outlet valve to achieve a decompression effect in the exhaust system.

In einer weiteren Ausführungsform beginnt das Schließen des mindestens einen Gasauslassventils am Ende des Ausschiebetaktes oder während des Ansaugtaktes in einem Bereich zwischen OT (oberen Totpunkt einer Kolbenbewegung eines Kolbens des jeweiligen Zylinders) und 30° KW nach OT. Damit kann das während des Expansionstaktes aus dem Abgastrakt in die Verbrennungskammer zurückströmende Gas in Abhängigkeit von einer Motordrehzahl im Ausschiebetakt entweder in den Abgastrakt durch das zumindest teilweise geöffnete eine Gasauslassventil direkt wieder ausgeschoben werden oder, bei höheren Motordrehzahlen, zumindest teilweise verdichtet und erst dann durch das zumindest eine teilweise geöffnete Gasauslassventil ausgeschoben werden. Bei höheren Drehzahlen kann es somit im Ausschiebetakt zu einer weiteren Kompression des Gases in der Verbrennungskammer mit anschließender Dekompression des verdichteten Gases in den Abgastrakt kommen, wodurch eine Motorbremswirkung des Verfahrens erhöht wird.In another embodiment, the closing of the at least one gas outlet valve begins at the end of the exhaust stroke or during the intake stroke in a range between TDC (top dead center of a piston movement of a piston of the respective cylinder) and 30 ° CA to TDC. Thus, the gas flowing back from the exhaust tract into the combustion chamber during the expansion stroke can either be directly expelled back into the exhaust tract through the at least partially opened gas outlet valve or, at higher engine speeds, at least partially compressed and only then through the exhaust gas at least one partially opened gas outlet valve are pushed out. At higher speeds, it may thus come in Ausschiebetakt to a further compression of the gas in the combustion chamber with subsequent decompression of the compressed gas in the exhaust system, whereby an engine braking effect of the method is increased.

Insbesondere kann sich das Schließen des mindestens einen Gasauslassventils mit einem Öffnen mindestens eines Gaseinlassventils überschneiden.In particular, the closing of the at least one gas outlet valve may overlap with an opening of at least one gas inlet valve.

In einem Ausführungsbeispiel wird beim Offenhalten des Gasauslassventils während des Expansionstaktes und des Ausschiebetaktes ein konstanter Ventilhub des mindestens einen Gasauslassventils gehalten. Dies ist steuerungstechnisch besonders einfach beispielsweise mit einer gleichbleibenden Höhe eines Nockens einer Nockenwelle realisierbar.In one embodiment, when the gas outlet valve is held open during the expansion stroke and the exhaust stroke, a constant valve lift of the at least one is achieved Gas outlet valve held. This is control technology particularly simple, for example, realized with a constant height of a cam of a camshaft.

In einem bevorzugten Ausführungsbeispiel sind je Zylinder zwei Gasauslassventile vorgesehen und nur eines der zwei Gasauslassventile wird während des Verdichtungstaktes teilweise geöffnet, während des Expansionstaktes und des Ausschiebetaktes mit einer teilweisen Öffnung offengehalten und am Ende des Ausschiebetaktes oder während des Ansaugtaktes geschlossen. Zusätzlich kann das andere der zwei Gasauslassventile während des Verdichtungstaktes, des Expansionstaktes, des Ausschiebetaktes und des Ansaugtaktes geschlossen sein. Damit können die Belastungen auf den mit den Gasauslassventilen verbundenen variablen Ventiltrieb verringert werden, da insbesondere nur eines der Gasauslassventile je Zylinder gegen den Druck in der Verbrennungskammer während des Verdichtungstaktes geöffnet werden muss.In a preferred embodiment, two gas outlet valves are provided per cylinder and only one of the two gas outlet valves is partially opened during the compression stroke, kept open with a partial opening during the expansion stroke and the exhaust stroke and closed at the end of the exhaust stroke or during the intake stroke. Additionally, the other of the two exhaust gas valves may be closed during the compression stroke, the expansion stroke, the exhaust stroke, and the intake stroke. Thus, the loads on the associated with the gas outlet valves variable valve train can be reduced because in particular only one of the gas outlet valves per cylinder must be opened against the pressure in the combustion chamber during the compression stroke.

In einer weiteren Ausführungsvariante weist das Verfahren zusätzlich ein Öffnen mindestens eines Gaseinlassventils des mindestens einen Zylinders während eines Ansaugtaktes und ein Geschlossen-Halten des mindestens einen Gaseinlassventils während des Verdichtungstaktes, des Expansionstaktes und des Ausschiebetaktes auf. Damit können die Gaseinlassventile während des Motorbremsbetriebs der Brennkraftmaschine wie im Normalbetrieb der Brennkraftmaschine betätigt werden. Damit muss die Betätigung der Gaseinlassventile für den Motorbremsbetrieb nicht umgeschaltet werden. Wie auch im Normalbetrieb werden die Gaseinlassventile im Motorbremsbetrieb dazu genutzt, Luft aus einem Luftzufuhrsystem der Brennkraftmaschine während des Ansaugtaktes in die Verbrennungskammern zu leiten.In a further embodiment variant, the method additionally comprises opening at least one gas inlet valve of the at least one cylinder during an intake stroke and closing the at least one gas inlet valve during the compression stroke, the expansion stroke and the exhaust stroke. Thus, the gas inlet valves during engine braking operation of the internal combustion engine can be operated as in normal operation of the internal combustion engine. Thus, the operation of the gas inlet valves for the engine braking operation does not have to be switched. As in normal operation, the gas inlet valves are used in engine braking operation to direct air from an air supply system of the internal combustion engine during the intake stroke in the combustion chambers.

Insbesondere kann das Verfahren ferner ein Schließen einer stromabwärts des mindestens einen Gasauslassventils vorgesehenen Stauklappe während des Verdichtungstaktes und/oder während des Ausschiebetaktes aufweisen. Die Stauklappe kann vorzugsweise im Abgastrakt angeordnet sein.In particular, the method may further include closing a damper provided downstream of the at least one gas outlet valve during the compression stroke and / or during the exhaust stroke. The storage flap may preferably be arranged in the exhaust tract.

Die vorliegende Erfindung betrifft auch einen variablen Ventiltrieb für eine Brennkraftmaschine. Der variable Ventiltrieb kann insbesondere als ein Schiebenockensystem ausgebildet sein. Der variable Ventiltrieb ist dazu ausgebildet, das Verfahren wie hierin offenbart durchzuführen.The present invention also relates to a variable valve train for an internal combustion engine. The variable valve train may in particular be designed as a sliding cam system. The variable valve train is configured to perform the method as disclosed herein.

Zusätzlich betrifft die vorliegende Offenbarung auch ein Kraftfahrzeug, insbesondere Nutzfahrzeug (zum Beispiel Omnibus oder Lastkraftwagen), mit einer Brennkraftmaschine aufweisend den variablen Ventiltrieb wie hierin offenbart.Additionally, the present disclosure also pertains to a motor vehicle, particularly commercial vehicle (eg, bus or truck) having an internal combustion engine having the variable valve train disclosed herein.

Es ist auch möglich, die Verfahren wie hierin offenbart bei Personenkraftwagen, Großmotoren, geländegängigen Fahrzeuge, stationären Motoren, Marinemotoren usw. zu verwenden.It is also possible to use the methods disclosed herein for passenger cars, large engines, off-highway vehicles, stationary engines, marine engines, and so on.

Die zuvor beschriebenen bevorzugten Ausführungsformen und Merkmale der Erfindung sind beliebig miteinander kombinierbar. Weitere Einzelheiten und Vorteile der Erfindung werden im Folgenden unter Bezug auf die beigefügten Zeichnungen beschrieben. Es zeigen:

Figur 1
eine Schemadarstellung eines Zylinders einer Brennkraftmaschine; und
Figur 2
ein Steuerdiagramm einer Ventilsteuerung einer Viertakt-Brennkraftmaschine.
The preferred embodiments and features of the invention described above can be combined with one another as desired. Further details and advantages of the invention will be described below with reference to the accompanying drawings. Show it:
FIG. 1
a schematic representation of a cylinder of an internal combustion engine; and
FIG. 2
a control diagram of a valve control of a four-stroke internal combustion engine.

Die Figur 1 zeigt einen Zylinder 12 einer Brennkraftmaschine 10. Die Brennkraftmaschine 10 ist eine Viertakt-Brennkraftmaschine, insbesondere eine Viertakt-Diesel-Brennkraftmaschine oder eine Viertakt-Benzin-Brennkraftmaschine. Vorzugsweise ist die Brennkraftmaschine 10 in einem Nutzfahrzeug, zum Beispiel einem Lastkraftwagen oder einem Omnibus, zum Antreiben des Nutzfahrzeugs umfasst.The FIG. 1 shows a cylinder 12 of an internal combustion engine 10. The internal combustion engine 10 is a four-stroke internal combustion engine, in particular a four-stroke diesel engine or a four-stroke gasoline internal combustion engine. Preferably, the internal combustion engine 10 in a commercial vehicle, for example, a truck or a bus, for driving the commercial vehicle comprises.

Der Zylinder 12 weist mindestens ein Gaseinlassventil 14, mindestens ein Gasauslassventil 16, eine Verbrennungskammer 18 und einen Kolben 20 auf.The cylinder 12 has at least one gas inlet valve 14, at least one gas outlet valve 16, a combustion chamber 18 and a piston 20.

Das mindestens eine Gaseinlassventil 14 verbindet die Verbrennungskammer 18 mit einem Luftzufuhrsystem der Brennkraftmaschine 10 zum Zuführen von Verbrennungsluft in die Verbrennungskammer 18. Das mindestens eine Gasauslassventil 16 verbindet die Verbrennungskammer 18 mit einem Abgasstrang der Brennkraftmaschine 10 zum Abführen von Abgasen. Beispielsweise können zwei Gaseinlassventile 14 und zwei Gasauslassventile 16 je Zylinder 12 und eine Mehrzahl von Zylindern 12 vorgesehen sein.The at least one gas inlet valve 14 connects the combustion chamber 18 to an air supply system of the internal combustion engine 10 for supplying combustion air into the combustion chamber 18. The at least one gas outlet valve 16 connects the combustion chamber 18 to an exhaust line of the internal combustion engine 10 for exhausting exhaust gases. For example, two gas inlet valves 14 and two gas outlet valves 16 per cylinder 12 and a plurality of cylinders 12 may be provided.

Das mindestens eine Gasauslassventil 16 kann über einen variablen Ventiltrieb 22 betätigt werden. Der variable Ventiltrieb 22 kann beispielsweise als ein Schiebenockensystem ausgebildet sein. Das Schiebenockensystem kann mindestens einen Nockenträger mit mindestens zwei Nocken aufweisen. Der Nockenträger kann drehfest und axial verschiebbar auf einer Nockenwelle angeordnet sein. Das mindestens eine Gaswechselventil wird in Abhängigkeit von einer Axialposition des Nockenträgers von verschiedenen Nocken des Nockenträgers betätigt. Es ist auch möglich, dass bei mehreren Gasauslassventilen 16 je Zylinder 12 die Gasauslassventile 16 des jeweiligen Zylinders 12 unterschiedlich betätigbar sind.The at least one gas outlet valve 16 can be actuated via a variable valve drive 22. The variable valve drive 22 may be formed, for example, as a sliding cam system. The sliding cam system may have at least one cam carrier with at least two cams. The cam carrier can be arranged rotationally fixed and axially displaceable on a camshaft. The at least one gas exchange valve is actuated by various cams of the cam carrier in response to an axial position of the cam carrier. It is also possible that with several gas outlet valves 16 per cylinder 12, the gas outlet valves 16 of the respective cylinder 12 are actuated differently.

Der Kolben 20 ist auf eine bekannte Art und Weise hin- und herbewegbar in dem Zylinder 12 angeordnet und mit einer Kurbelwelle 24 verbunden.The piston 20 is reciprocably disposed in the cylinder 12 in a known manner and connected to a crankshaft 24.

In Figur 2 ist ein beispielhaftes Steuerdiagramm für die Betätigung der Gaseinlassventile 14 und der Gasauslassventile 16 von Figur 1 während eines Motorbremsbetriebs der Brennkraftmaschine 10 dargestellt.In FIG. 2 is an exemplary control diagram for the operation of the gas inlet valves 14 and the gas outlet valves 16 of FIG. 1 during engine braking operation of the engine 10.

Eine strichpunktierte Kurve A zeigt einen Ventilhub der Gaseinlassventile 14 in Abhängigkeit von einem Kurbelwinkel der Kurbelwelle 24. Eine gestrichelte Kurve B zeigt einen Ventilhub des Gasauslassventils 16 in Abhängigkeit von dem Kurbelwinkel der Kurbelwelle 24. Eine durchgezogene Kurve C zeigt einen Zylinderdruck in der Verbrennungskammer 18 in Abhängigkeit von einem Kurbelwinkel der Kurbelwelle 24 bei einer niedrigen Motordrehzahl. Eine gepunktete Kurve D zeigt einen Zylinderdruck in der Verbrennungskammer 18 in Abhängigkeit von einem Kurbelwinkel der Kurbelwelle 24 bei einer hohen Motordrehzahl.A broken line A shows a valve lift of the gas inlet valves 14 in dependence on a crank angle of the crankshaft 24. A dashed curve B shows a valve lift of the gas exhaust valve 16 as a function of the crank angle of the crankshaft 24. A solid curve C shows a cylinder pressure in the combustion chamber 18 in FIG Dependence on a crank angle of the crankshaft 24 at a low engine speed. A dotted curve D shows a cylinder pressure in the combustion chamber 18 in response to a crank angle of the crankshaft 24 at a high engine speed.

Die Kurven A bis D sind über die im Viertaktbetrieb üblichen 720° Kurbelwinkel (KW) aufgetragen, wobei die linke Achse des Diagramms die Zylinderdrücke in bar und die rechte Achse die Ventilhübe in mm angeben.The curves A to D are plotted against the usual in four-stroke operation 720 ° crank angle (KW), the left axis of the graph indicate the cylinder pressures in bar and the right axis the valve strokes in mm.

Gemäß der Kurve A werden die Gaseinlassventile 14 während des Motorbremsbetriebs wie auch im regulären Betrieb während des Ansaugtaktes geöffnet. Über den weiteren Steuerzyklus sind die Gaseinlassventile 14 geschlossen.According to the curve A, the gas inlet valves 14 are opened during the engine braking operation as well as in the regular operation during the intake stroke. Over the further control cycle, the gas inlet valves 14 are closed.

Während des Motorbremsbetriebs werden die Gasauslassventile 16 anders als im regulären Betrieb (Normalbetrieb), in dem die Gasauslassventile 16 nur während des Ausschiebetaktes geöffnet sind, gesteuert. Beispielsweise kann die Brennkraftmaschine je Zylinder 12 zwei Gasauslassventile 16 aufweisen, von denen eines während des Motorbremsbetriebs vollständig geschlossen gehalten wird und das andere während des Motorbremsbetriebs gemäß der Kurve B gesteuert wird.During the engine braking operation, the gas exhaust valves 16 are controlled unlike in the regular operation (normal operation) in which the gas exhaust valves 16 are opened only during the exhaust stroke. For example, the engine per cylinder 12 may have two exhaust gas valves 16, one of which is kept fully closed during engine braking operation and the other is controlled according to curve B during engine braking operation.

Gemäß der Kurve B wird das Gasauslassventil 16 ungefähr 60°KW bis 100°KW vor dem oberen Zündtotpunkt, d. h. vor dem Ende des Verdichtungstaktes, teilweise geöffnet. Das Gasauslassventil 16 wird dann während des Expansionstaktes und des Ausschiebetaktes für ungefähr 360°KW teilweise offen gehalten. Das teilweise geöffnete Gasauslassventil 16 wird nach dem Ausschiebetakt wieder geschlossen und verbleibt bis zur erneuten Öffnung im Verdichtungstakt geschlossen.According to the curve B, the gas exhaust valve 16 becomes about 60 ° CA to 100 ° CA before the upper ignition dead center, that is, the engine exhaust gas. H. before the end of the compression stroke, partially open. The gas outlet valve 16 is then partially kept open during the expansion stroke and the exhaust stroke for approximately 360 ° CA. The partially open gas outlet valve 16 is closed again after the Ausschiebetakt and remains closed until reopening in the compression stroke.

Das Gasauslassventil 16 wird gemäß der Kurve B nur teilweise geöffnet. Die teilweise Öffnung kann einem Ventilhub von 0,5 mm bis 3 mm entsprechen. Im Gegensatz dazu kann ein Maximalhub (regulärer Hub) das Gasauslassventils 16 beispielsweise zwischen ungefähr 10 mm für kleine Brennkraftmaschinen 10 und bis zu ungefähr 16 mm für sehr große Brennkraftmaschinen 10 im Nutzfahrzeugbau sein.The gas outlet valve 16 is only partially opened according to the curve B. The partial opening may correspond to a valve lift of 0.5 mm to 3 mm. In contrast, a maximum lift (regular stroke) of the gas exhaust valve 16 may be, for example, between about 10 mm for small internal combustion engines 10 and up to about 16 mm for very large internal combustion engines 10 in commercial vehicle construction.

Durch die nur teilweise Öffnung des Gasauslassventils 16 gemäß der Kurve B können unterschiedliche Zylinderdruckverläufe in der Verbrennungskammer 18 bei unterschiedlichen Drehzahlen der Brennkraftmaschine 10 erzielt werden.Due to the only partial opening of the gas outlet valve 16 according to the curve B different cylinder pressure curves in the combustion chamber 18 at different speeds of the internal combustion engine 10 can be achieved.

Gemäß der Kurve C kommt es bei niedrigen Drehzahlen der Brennkraftmaschine 10 bis beispielsweise ungefähr 1200 U/min zu keiner Verdichtung in der Verbrennungskammer 18 während des Ausschiebetaktes. Der Grund hierfür liegt in dem Ventilspalt durch das teilweise geöffnete Gasauslassventil 16. Dieser Ventilspalt reicht bei niedrigen Geschwindigkeiten des Kolbens 20 aus, um das in der Verbrennungskammer 18 befindliche Gas ohne Druckanstieg aus der Verbrennungskammer 18 durch das teilweise geöffnete Gasauslassventil 16 strömen zu lassen. Die Kurve C bezieht sich beispielsweise auf einen Zylinderdruckverlauf bei einer Motordrehzahl der Brennkraftmaschine von ungefähr 600 U/min.According to the curve C, at low rotational speeds of the internal combustion engine 10 to, for example, about 1200 rpm, no compression occurs in the combustion chamber 18 during the exhaust stroke. This is due to the valve gap through the partially opened gas outlet valve 16. This valve gap is sufficient at low velocities of the piston 20 to allow the gas in the combustion chamber 18 to flow from the combustion chamber 18 through the partially opened gas outlet valve 16 without increasing pressure. The curve C relates, for example, to a cylinder pressure curve at an engine speed of the internal combustion engine of approximately 600 rpm.

Hingegen kommt es gemäß der Kurve D bei hohen Drehzahlen der Brennkraftmaschine 10 ab beispielsweise 1200 U/min bis 1500 U/min zu einer Verdichtung in der Verbrennungskammer 18 während des Ausschiebetaktes. Durch die erhöhte Motordrehzahl steigt auch die Kolbengeschwindigkeit des Kolbens 20 an und der Volumenstrom über dem teilweise geöffneten Gasauslassventil 16 steigt ebenfalls an. Der durch das teilweise geöffnete Gasauslassventil 16 bereitgestellte Ventilspalt reicht nicht mehr aus, um das Gas ohne Verdichtung auszuschieben. Stattdessen kommt es zu einer zweiten Verdichtung vor dem oberen Totpunkt am Ende des Ausschiebetaktes. Bei der zweiten Verdichtung wird Kompressionsenergie durch das weiterhin geöffnete Gasauslassventil 16 dissipiert und Bremsleistung erzeugt. Im Einzelnen bremst die Verdichtungsarbeit den Kolben 20, wodurch die Brennkraftmaschine 10 im Motorbremsbetrieb gebremst wird. Die Kurve D bezieht sich beispielsweise auf einen Zylinderdruckverlauf bei einer Motordrehzahl der Brennkraftmaschine von ungefähr 2600 U/min.On the other hand, according to the curve D at high rotational speeds of the internal combustion engine 10 from, for example, 1200 rpm to 1500 rpm, compression occurs in the combustion chamber 18 during the exhaust stroke. Due to the increased engine speed, the piston speed of the piston 20 increases and the volume flow over the partially opened gas outlet valve 16 also increases. The valve gap provided by the partially opened gas outlet valve 16 is no longer sufficient to push out the gas without compression. Instead, there is a second compression before top dead center at the end of Ausschiebetaktes. In the second compression, compression energy is dissipated by the still open gas outlet valve 16 and braking power is generated. In particular, the compression work brakes the piston 20, whereby the internal combustion engine 10 is braked during engine braking operation. For example, the curve D refers to a cylinder pressure history at an engine speed of the engine of about 2600 rpm.

Bei beiden Kurven C und D kommt es zu einer ersten Verdichtung in der Verbrennungskammer 18 während des Verdichtungstaktes, da das Gasauslassventil 16 erst zum Ende des Verdichtungstaktes geöffnet wird. Durch die Öffnung des Gasauslassventils 16 kommt es zu einer Dekompression des verdichteten Gases in den Abgastrakt, in dem beispielsweise eine in diesem Moment geschlossene Stauklappe vorgesehen ist. Die vom Kolben 20 aufgebrachte Verdichtungsarbeit bremst wiederum die Brennkraftmaschine 10. Aufgrund der höheren Kolbengeschwindigkeit des Kolbens 20 kommt es gemäß Kurve D bei höheren Motordrehzahlen zu einer größeren Verdichtung in der Verbrennungskammer 18 und somit zu einer größeren Bremswirkung als bei niedrigen Motordrehzahl gemäß Kurve C.In both curves C and D, there is a first compression in the combustion chamber 18 during the compression stroke, since the gas outlet valve 16 is opened only at the end of the compression stroke. Due to the opening of the gas outlet valve 16, the compressed gas is decompressed into the exhaust gas tract, in which, for example, a stowage flap closed at this moment is provided. The compression work applied by the piston 20 in turn brakes the internal combustion engine 10. Due to the higher piston speed of the piston 20, curve D increases at higher engine speeds a greater compression in the combustion chamber 18 and thus to a greater braking effect than at low engine speed according to curve C.

Während des Expansionstaktes sind die Zylinderdrücke bei den Kurven C und D niedrig und es kann durch den Abgasstau im Abgastrakt Luft aus dem Abgastrakt zurück in die Verbrennungskammer 18 durch das teilweise geöffnete Gasauslassventil 16 strömen.During the expansion stroke, the cylinder pressures at curves C and D are low and air may flow from the exhaust tract back into the combustion chamber 18 through the partially opened gas outlet valve 16 through the exhaust stack.

Zusammenfassend kommt es bei niedrigen Motordrehzahl unterhalb einer Grenzdrehzahl, die bspw. zwischen 1200 U/min und 1500 U/min liegt, gemäß der Kurve C zu lediglich einer Kompression von Gas in der Verbrennungskammer 18 und Dekompression des verdichteten Gases in den Abgastrakt. Diese einmalige Kompression-Dekompression findet im Verdichtungstakt statt. Bei einer hohen Motordrehzahl oberhalb der Grenzdrehzahl kommt es mit der gleichen Steuerkurve (Kurve B) für das gleiche Gasauslassventil 16 gemäß der Kurve D zu einer zweifachen Kompression von Gas in der Verbrennungskammer 18 und Dekompression des verdichteten Gases in den Abgastrakt durch das teilweise geöffnete Gasauslassventil 16. Einerseits kommt es im Verdichtungstakt zu einer ersten Kompression mit anschließender Dekompression. Zusätzlich kommt es im Ausschiebetakt zu einer zweiten Kompression mit anschließender Dekompression.In summary, at low engine speed below a threshold speed, for example, between 1200 rpm and 1500 rpm, according to curve C, only compression of gas in the combustion chamber 18 and decompression of the compressed gas into the exhaust tract occurs. This unique compression-decompression takes place in the compression stroke. At a high engine speed above the limit speed occurs with the same control curve (curve B) for the same gas outlet valve 16 according to the curve D to double compression of gas in the combustion chamber 18 and decompression of the compressed gas in the exhaust gas through the partially opened gas outlet valve sixteenth On the one hand, there is a first compression in the compression stroke with subsequent decompression. In addition, there is a second compression in the Ausschiebetakt with subsequent decompression.

Ein Übergang zwischen den Kurven C und D erfolgt mit zunehmender Motordrehzahl der Brennkraftmaschine 10 stetig.A transition between the curves C and D takes place continuously with increasing engine speed of the internal combustion engine 10.

Die Erfindung ermöglicht somit auf besonders vorteilhafte Weise, dass mit ein und demselben Steuerprofil für ein Gasauslassventil 16 bei hohen Drehzahlen der Brennkraftmaschine 10 eine hohe Bremswirkung durch die doppelte Kompression-Dekompression erzielt wird (Kurve D). Bei niedrigen Drehzahlen wird ebenso eine (geringe) Bremswirkung durch die einmalige Kompression-Dekompression erzielt (Kurve C), wobei eine Motoranregung aufgrund des Verzichts auf die zweite Kompression-Dekompression verhindert oder zumindest reduziert wird. Das Verfahren passt sich somit selbst an die Umgebungsbedingungen (die Motordrehzahl) an, sodass kein zusätzlicher Steuerungseingriff von außen notwendig ist.The invention thus makes it possible in a particularly advantageous manner that with the same control profile for a gas outlet valve 16 at high rotational speeds of the internal combustion engine 10, a high braking effect is achieved by the double compression-decompression (curve D). At low speeds as well, a (small) braking effect is achieved by the one-time compression-decompression (curve C), whereby motor excitation due to the omission of the second compression-decompression is prevented or at least reduced. The process thus adapts itself to the ambient conditions (the engine speed), so that no additional control intervention from the outside is necessary.

Die Erfindung ist nicht auf die vorstehend beschriebenen bevorzugten Ausführungsbeispiele beschränkt. Vielmehr ist eine Vielzahl von Varianten und Abwandlungen möglich, die ebenfalls von dem Erfindungsgedanken Gebrauch machen und deshalb in den Schutzbereich fallen. Insbesondere beansprucht die Erfindung auch Schutz für den Gegenstand und die Merkmale der Unteransprüche unabhängig von den in Bezug genommenen Ansprüchen. Insbesondere sind die Merkmale der Unteransprüche auch unabhängig von sämtlichen Merkmalen des unabhängigen Anspruchs 1 und beispielsweise unabhängig von den Merkmalen bezüglich desteilweisen Öffnens mindestens eines Gasauslassventils während eines Verdichtungstaktes, des Haltens einer teilweisen Öffnung des mindestens einen Gasauslassventils während eines Expansionstaktes und/oder Ausschiebetaktes und/oder des Schließens des teilweise geöffneten mindestens einen Gasauslassventils am Ende des Ausschiebetaktes oder während eines Ansaugtaktes des unabhängigen Anspruchs 1 offenbart.The invention is not limited to the preferred embodiments described above. Rather, a variety of variants and modifications is possible, which also make use of the inventive idea and therefore fall within the scope. In particular, the invention also claims protection of the subject matter and the features of the subclaims independently of the claims referred to. In particular The features of the subclaims are also independent of all features of independent claim 1 and, for example, independent of the characteristics regarding at least one opening of at least one gas outlet valve during a compression stroke, holding a partial opening of the at least one gas outlet valve during an expansion stroke and / or Ausschiebetaktes and / or Closing the partially open at least one gas outlet valve at the end of Ausschiebetaktes or during an intake stroke of the independent claim 1 disclosed.

BezugszeichenlisteLIST OF REFERENCE NUMBERS

1010
BrennkraftmaschineInternal combustion engine
1212
Zylindercylinder
1414
GaseinlassventilGas inlet valve
1616
Gasauslassventilgas outlet
1818
Verbrennungskammercombustion chamber
2020
Kolbenpiston
2222
Variabler VentiltriebVariable valve train
2424
Kurbelwellecrankshaft
AA
Steuerkurve für GaseinlassventilControl curve for gas inlet valve
BB
Steuerkurve für GasauslassventilControl curve for gas outlet valve
CC
Zylinderdruckverlauf bei niedriger MotordrehzahlCylinder pressure curve at low engine speed
DD
Zylinderdruckverlauf bei hoher MotordrehzahlCylinder pressure curve at high engine speed

Claims (15)

Verfahren zum Bremsen einer Brennkraftmaschine (10), insbesondere einer Viertakt-Brennkraftmaschine, aufweisend: teilweises Öffnen mindestens eines Gasauslassventils (16) mindestens eines Zylinders (12) der Brennkraftmaschine (10) während eines Verdichtungstaktes der Brennkraftmaschine (10); Halten einer teilweisen Öffnung des mindestens einen Gasauslassventils (16) während eines an den Verdichtungstakt anschließenden Expansionstaktes der Brennkraftmaschine (10) und während eines an den Expansionstakt anschließenden Ausschiebetaktes der Brennkraftmaschine (10); und Schließen des teilweise geöffneten mindestens einen Gasauslassventils (16) am Ende des Ausschiebetaktes oder während eines an den Ausschiebetakt anschließenden Ansaugtaktes der Brennkraftmaschine (10). Method for braking an internal combustion engine (10), in particular a four-cycle internal combustion engine, comprising: partially opening at least one gas outlet valve (16) of at least one cylinder (12) of the internal combustion engine (10) during a compression stroke of the internal combustion engine (10); Holding a partial opening of the at least one gas outlet valve (16) during an expansion stroke of the internal combustion engine (10) following the compression stroke and during an exhaust stroke of the internal combustion engine (10) following the expansion stroke; and Closing the partially open at least one gas outlet valve (16) at the end of the Ausschiebetaktes or during an adjoining the Ausschiebetakt intake stroke of the internal combustion engine (10). Verfahren nach Anspruch 1, wobei: das mindestens eine Gasauslassventil (16) beim teilweisen Öffnen so weit geöffnet wird, dass es bei einer Drehzahl der Brennkraftmaschine (10) unterhalb einer Grenzdrehzahl der Brennkraftmaschine (10) zu im Wesentlichen keiner Verdichtung im jeweiligen Zylinder (12) während des Ausschiebetaktes kommt. The method of claim 1, wherein: the at least one gas outlet valve (16) during partial opening is opened so far that at a speed of the internal combustion engine (10) below a limit speed of the internal combustion engine (10) substantially no compression in the respective cylinder (12) during Ausschiebetaktes. Verfahren nach Anspruch 2, wobei: das mindestens eine Gasauslassventil (16) beim teilweisen Öffnen so weit geöffnet wird, dass es bei einer Drehzahl der Brennkraftmaschine (10) oberhalb der Grenzdrehzahl zu einer Verdichtung im jeweiligen Zylinder (12) während des Ausschiebetaktes kommt. The method of claim 2, wherein: the at least one gas outlet valve (16) during partial opening is opened so far that it comes at a speed of the internal combustion engine (10) above the limit speed to a compression in the respective cylinder (12) during the Ausschiebetaktes. Verfahren nach Anspruch 3, wobei: die Verdichtung im jeweiligen Zylinder (12) bei zunehmender Drehzahl der Brennkraftmaschine (10) im Ausschiebetakt oberhalb der Grenzdrehzahl zunimmt. The method of claim 3, wherein: the compression in the respective cylinder (12) increases with increasing speed of the internal combustion engine (10) in Ausschiebetakt above the limit speed. Verfahren nach einem der Ansprüche 2 bis 4, wobei: die Grenzdrehzahl in einem Bereich zwischen 1000 U/min und 1700 U/min, insbesondere in einem Bereich zwischen 1200 U/min und 1500 U/min, liegt. Method according to one of claims 2 to 4, wherein: the limit speed is in a range between 1000 U / min and 1700 U / min, in particular in a range between 1200 U / min and 1500 U / min. Verfahren nach einem der vorherigen Ansprüche, wobei: das mindestens eine Gasauslassventil (16) beim teilweisen Öffnen in einem Bereich zwischen 5 % und 30 % eines maximalen Ventilhubs des mindestens einen Gasauslassventils (16) geöffnet wird; und/oder das mindestens eine Gasauslassventil (16) beim teilweisen Öffnen in einem Bereich zwischen 0,5 mm und 3 mm geöffnet wird. Method according to one of the preceding claims, wherein: the at least one gas outlet valve (16) is opened during partial opening in a range between 5% and 30% of a maximum valve lift of the at least one gas outlet valve (16); and or the at least one gas outlet valve (16) is opened during partial opening in a range between 0.5 mm and 3 mm. Verfahren nach Anspruch 6, wobei ein maximaler Ventilhub in einem Bereich zwischen 10 mm und 16 mm liegt.The method of claim 6, wherein a maximum valve lift is in a range between 10 mm and 16 mm. Verfahren nach einem der vorherigen Ansprüche, wobei: das teilweise Öffnen des mindestens einen Gasauslassventils (16) während des Verdichtungstaktes in einem Bereich zwischen 100° KW und 60° KW vor OT beginnt. Method according to one of the preceding claims, wherein: the partial opening of the at least one gas outlet valve (16) begins during the compression stroke in a range between 100 ° CA and 60 ° CA before TDC. Verfahren nach einem der vorherigen Ansprüche, wobei: das Schließen des mindestens einen Gasauslassventils (16) am Ende des Ausschiebetaktes oder während des Ansaugtaktes in einem Bereich zwischen OT und 30° KW nach OT beginnt. Method according to one of the preceding claims, wherein: the closing of the at least one gas outlet valve (16) begins at the end of the exhaust stroke or during the intake stroke in a range between OT and 30 ° CA after TDC. Verfahren nach einem der vorherigen Ansprüche, wobei: beim Offenhalten des Gasauslassventils (16) während des Expansionstaktes und des Ausschiebetaktes ein konstanter Ventilhub des mindestens einen Gasauslassventils (16) gehalten wird. Method according to one of the preceding claims, wherein: keeping open the gas outlet valve (16) during the expansion stroke and the Ausschiebetaktes a constant valve lift of the at least one gas outlet valve (16). Verfahren nach einem der vorherigen Ansprüche, wobei: je Zylinder (12) zwei Gasauslassventile (16) vorgesehen sind und nur eines der zwei Gasauslassventile (16) während des Verdichtungstaktes teilweise geöffnet, während des Expansionstaktes und des Ausschiebetaktes mit einer teilweisen Öffnung offengehalten und am Ende des Ausschiebetaktes oder während des Ansaugtaktes geschlossen wird. Method according to one of the preceding claims, wherein: two gas outlet valves (16) are provided per cylinder (12) and only one of the two gas outlet valves (16) is partially opened during the compression stroke, kept open with a partial opening during the expansion stroke and the exhaust stroke, and closed at the end of the exhaust stroke or during the intake stroke. Verfahren nach Anspruch 11, wobei: das andere der zwei Gasauslassventile (16) während des Verdichtungstaktes, des Expansionstaktes, des Ausschiebetaktes und des Ansaugtaktes geschlossen ist. The method of claim 11, wherein: the other of the two gas outlet valves (16) is closed during the compression stroke, the expansion stroke, the exhaust stroke, and the intake stroke. Verfahren nach einem der vorherigen Ansprüche, ferner aufweisend: Öffnen mindestens eines Gaseinlassventils (14) des mindestens einen Zylinders (12) während eines Ansaugtaktes; und Geschlossen-Halten des mindestens einen Gaseinlassventils (14) während des Verdichtungstaktes, des Expansionstaktes und des Ausschiebetaktes. The method of any one of the preceding claims, further comprising: Opening at least one gas inlet valve (14) of the at least one cylinder (12) during an intake stroke; and Keeping closed the at least one gas inlet valve (14) during the compression stroke, the expansion stroke and the Ausschiebetaktes. Variabler Ventiltrieb (22), insbesondere Schiebenockensystem, für eine Brennkraftmaschine (10), wobei der variable Ventiltrieb (22) dazu ausgebildet ist, das Verfahren nach einem der vorherigen Ansprüche durchzuführen.Variable valve train (22), in particular sliding cam system, for an internal combustion engine (10), wherein the variable valve train (22) is designed to carry out the method according to one of the preceding claims. Kraftfahrzeug, insbesondere Nutzfahrzeug, mit einer Brennkraftmaschine (10) aufweisend den variablen Ventiltrieb nach Anspruch 14.Motor vehicle, in particular utility vehicle, with an internal combustion engine (10) having the variable valve drive according to claim 14.
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CN109611223B (en) 2022-09-27
BR102018067605A2 (en) 2019-04-24
US10738717B2 (en) 2020-08-11
EP3450732B1 (en) 2022-07-06
DE102017120150A1 (en) 2019-03-07

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