EP1658423A1 - Internal combustion engine comprising an engine braking mechanism - Google Patents

Internal combustion engine comprising an engine braking mechanism

Info

Publication number
EP1658423A1
EP1658423A1 EP04741405A EP04741405A EP1658423A1 EP 1658423 A1 EP1658423 A1 EP 1658423A1 EP 04741405 A EP04741405 A EP 04741405A EP 04741405 A EP04741405 A EP 04741405A EP 1658423 A1 EP1658423 A1 EP 1658423A1
Authority
EP
European Patent Office
Prior art keywords
exhaust gas
internal combustion
combustion engine
exhaust
turbine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04741405A
Other languages
German (de)
French (fr)
Inventor
Rainer Albat
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mercedes Benz Group AG
Original Assignee
DaimlerChrysler AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DaimlerChrysler AG filed Critical DaimlerChrysler AG
Publication of EP1658423A1 publication Critical patent/EP1658423A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F02B37/24—Control of the pumps by using pumps or turbines with adjustable guide vanes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/005—Exhaust driven pumps being combined with an exhaust driven auxiliary apparatus, e.g. a ventilator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B41/00—Engines characterised by special means for improving conversion of heat or pressure energy into mechanical power
    • F02B41/02—Engines with prolonged expansion
    • F02B41/10—Engines with prolonged expansion in exhaust turbines
    • 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
    • F01L13/06—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for braking
    • 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
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F02B37/22—Control of the pumps by varying cross-section of exhaust passages or air passages, e.g. by throttling turbine inlets or outlets or by varying effective number of guide conduits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86863—Rotary valve unit
    • Y10T137/86871—Plug

Definitions

  • the invention relates to an internal combustion engine with an engine brake device according to the preamble of claim 1.
  • the internal combustion engine has an exhaust gas turbocharger, the exhaust gas turbine of which is provided in an exhaust tract and the compressor of which is provided in an intake tract of the internal combustion engine. Downstream of the exhaust gas turbine there is a utility turbine driven by the exhaust gas of the internal combustion engine and coupled to the internal combustion engine via a transmission.
  • a bypass device is provided in an exhaust gas line downstream of the utility turbine, which allows a bypass line to be opened or closed around the utility turbine.
  • the bypass device is designed as a variable switching valve in the form of a flap valve.
  • the exhaust gas from the internal combustion engine drives the exhaust gas turbine, which drives the compressor via a common shaft.
  • the compressor sucks in air and conveys the compressed air into the intake tract of the internal combustion engine.
  • the exhaust gas from the internal combustion engine first flows into the exhaust gas turbine of the exhaust gas turbocharger and then further into the utility turbine, which feeds the remaining energy in the exhaust gas back to the internal combustion engine via the transmission.
  • fuel injection is deactivated and the compression brake is activated.
  • the compression brake opens at least one exhaust valve provided on the cylinder head for a short period of time.
  • the compressed air in the combustion chamber then escapes into the exhaust tract when the exhaust valve is open.
  • the internal combustion engine only performs compression work and thereby generates braking power.
  • the compression work depends on the degree of filling of the cylinders.
  • the exhaust gas back pressure after the exhaust gas turbine must be low.
  • the utility turbine downstream of the exhaust gas turbine represents a throttle that increases the exhaust gas back pressure.
  • the utility turbine driven by the exhaust gas drives the internal combustion engine.
  • the bypass device opens in order to reduce the exhaust gas back pressure and not drive the power turbine.
  • the exhaust gas flows into the bypass line past the utility turbine.
  • the braking power generated by a clocked compression brake shows a flat, approximately linear course over the speed. This means that the braking power is low at low to medium speeds.
  • the object of the invention is to provide an internal combustion engine of the type mentioned at the beginning, the braking power of which is significantly increased at low and medium engine speeds.
  • the braking power increases, even at medium to high engine speeds.
  • the internal combustion engine according to the invention is characterized by the bypass device, which is designed in the form of a combined switching and throttle valve, so that the exhaust line can be closed completely and the bypass line completely or partially.
  • An exhaust gas turbocharger and a power turbine are provided on the internal combustion engine with an engine brake device in the form of a compression brake.
  • the exhaust gas turbocharger has an exhaust gas turbine which has an exhaust tract and a compressor which is assigned to an intake tract.
  • the utility turbine is downstream of the exhaust gas turbine arranged and coupled via a gearbox to the internal combustion engine.
  • the exhaust gas turbine and the power turbine are connected to one another via a connecting line.
  • a bypass line branches off from the connecting line.
  • the bypass device is provided in the bypass line around the utility turbine.
  • the bypass device controls the amount of bypassed exhaust gas around the utility turbine.
  • the bypass device opens or closes the exhaust line, which leads from the utility turbine to the bypass device.
  • the bypass device is designed such that when the exhaust line and the bypass line are completely closed by the bypass device, they can be closed gas-tight.
  • the exhaust line and the bypass line are completely closed by the bypass device, they can be closed gas-tight.
  • the bypass device is designed in the form of a rotary slide valve.
  • the advantage of using a rotary valve as a bypass device lies in the low actuation forces even at high exhaust gas pressures.
  • the rotary slide valve has a housing with a tubular channel inserted therein, in which a freely rotatable rotor is mounted, which is designed with a cross section in the form of a circular section.
  • the housing has an opening the exhaust line, an opening to the bypass line and an opening to an exhaust line through which the exhaust gas can flow into the atmosphere or an exhaust system.
  • the channel allows the exhaust line and the bypass line to communicate with the exhaust line or to establish a connection.
  • the circular cross-section of the rotor is selected so that the rotor can either completely close the exhaust line and the bypass channel or only the exhaust line or the exhaust line and partially close the bypass line.
  • the circular section-shaped cross section of the rotor has a circular section angle of 120 ° to 140 °.
  • the compression brake opens in the engine brake mode and the bypass device closes the exhaust line and the bypass line in the engine brake mode at low to medium engine speeds.
  • the compression brake is preferably designed in the form of a known constant throttle.
  • the constant throttle egg is designed as an additional throttle valve in the cylinder head, which can be opened continuously during engine braking.
  • the throttle valve opens or closes a bypass around an exhaust valve of a cylinder of the internal combustion engine, so that compressed air gets into the exhaust tract.
  • the constant throttle opens and releases at least part of the compression work.
  • the bypass device closes the exhaust line and the bypass line in engine braking mode. This also increases the pumping power of the internal combustion engine.
  • the advantage of using a constant throttle with the bypass device as a dust brake is the increased braking power at low to medium engine speeds. There is also no need for a brake flap in the exhaust system.
  • the compression brake opens in the engine brake mode and the exhaust gas turbine, which has a variable turbine geometry, which changes the flow of the exhaust gas onto a turbine wheel in the engine brake mode so that an increase in the speed of the exhaust gas turbine in the engine brake mode at medium to high engine speeds takes place
  • the bypass device closes the exhaust line and opens the bypass line completely.
  • the variable turbine geometry is designed as a known guide vane, in particular as a radial guide vane with adjustable or fixed guide vanes.
  • the radial guide grid reduces an effective turbine cross-section when the engine is braking, so that the exhaust gas speed increases. This increases the speed of the exhaust gas turbine.
  • Increasing the speed of the exhaust gas turbine also increases the speed of a compressor, which increases the boost pressure.
  • the bypass device closes the exhaust line and opens the bypass line in engine braking mode.
  • the exhaust gas flows through the bypass line past the utility turbine. This reduces the exhaust gas back pressure after the exhaust gas turbine.
  • the speed of the exhaust gas turbine increases due to the increased pressure difference. This advantageously leads to an additional boost pressure increase and thus to an increased braking power.
  • the power turbine contributes to the braking power, since the internal combustion engine drives the power turbine and the power turbine does not deliver energy from the exhaust gas to the internal combustion engine.
  • the compression brake opens in the engine brake mode and the exhaust gas turbine, which has a variable turbine geometry, which changes the flow of the exhaust gas onto a turbine wheel in the engine brake mode so that an increase in the speed of the internal combustion engine increases at high to very high engine speeds Exhaust gas turbine takes place, the bypass device closing the exhaust line and partially closing the bypass line.
  • the exhaust gas turbocharger is optimally designed for the combustion operation of the internal combustion engine. Critical exhaust gas turbocharger speeds can therefore be exceeded in engine braking operation, in particular if an exhaust gas turbine of an exhaust gas turbocharger has a variable turbine geometry. In engine braking mode, the variable turbine geometry serves to increase the speed of the exhaust gas turbocharger.
  • the exhaust gas back pressure increases after the exhaust gas turbine, which leads to a reduction in the pressure difference at the exhaust gas turbine and to a reduction in the speed of the exhaust gas turbocharger.
  • the advantage lies in the omission of a speed-regulating measure on the exhaust gas turbocharger, for example a waste gate valve.
  • the exhaust valves of the internal combustion engine in engine braking operation, can be opened briefly by pressure peaks in the exhaust gas in the exhaust tract, as a result of which exhaust gas from the exhaust tract enters the cylinders of the internal combustion engine. It is possible to open the exhaust valves briefly, especially at low cylinder pressures. This leads, particularly at the end of the first work cycle (intake) or at the start of the second work cycle (compression), to a recharging effect in which exhaust gas from the exhaust system travels into the cylinders of the internal combustion engine. The leads advantageously Reloading effect to an increased cylinder charge and thus increased engine braking power.
  • FIG. 1 shows a schematically simplified illustration of an internal combustion engine which is equipped with an engine brake device, an exhaust gas turbocharger and a utility turbine,
  • FIG. 2 shows a schematically simplified illustration of the rotary slide valve according to the invention with an open exhaust gas line and a closed bypass line
  • FIG. 3 shows a schematically simplified illustration of the rotary slide valve according to the invention with closed exhaust pipe and closed bypass pipe
  • FIG. 4 shows a schematically simplified illustration of the rotary slide valve according to the invention with the exhaust pipe closed and the bypass pipe open and
  • FIG. 5 shows a schematically simplified representation of the rotary slide valve according to the invention with the exhaust gas line closed and with the bypass line partially open.
  • the engine brake device 2 is preferably designed as a constant throttle in the form of a known compression brake.
  • the exhaust gas turbocharger 3 has an exhaust gas turbine 5 and a compressor 6, which are connected to one another via a common shaft 7.
  • the exhaust gas turbine 5 is assigned to an exhaust tract 8 and the compressor 6 is assigned to an intake tract 9 of the internal combustion engine 1.
  • a charge air cooler (not shown in detail) can be introduced in the intake tract 9.
  • the utility turbine 4 is provided downstream of the exhaust gas turbine 5 and is coupled to the internal combustion engine 1 via a transmission 10.
  • the exhaust gas turbine 5 is equipped with a variable turbine geometry 11.
  • the variable turbine geometry 11 is designed as a radial guide vane with adjustable or fixed guide vanes. With the help of the radial guide vane 11, the exhaust gas flow in front of a turbine wheel on the blades of the turbine wheel of the exhaust gas turbine 5 can be changed.
  • the radial guide grill 11 can be actuated electrically, pneumatically or hydraulically by an actuating device, not shown in more detail, which engages the radial guide grill 10 and is located outside a housing of the exhaust gas turbine 5.
  • the actuation device is controlled by means of an electronic engine control unit 12, which is connected to the actuation device via a first control line 13.
  • the exhaust gas turbine 5 and the power turbine 4 are connected to one another via a connecting line 14.
  • a bypass line 15 branches off from the connecting line 14.
  • a bypass device 16 is provided in the bypass line 15 around the utility turbine 4.
  • the bypass device 16 controls the amount of bypassed exhaust gas around the power turbine 4.
  • the bypass device 16 opens or closes an exhaust line 17 which leads from the power turbine 4 to the bypass device 16.
  • the bypass device 16 is controlled by means of the engine control unit 12 via a second control line 18.
  • the engine control unit 12 controls the constant throttle 2 via a third control line 19.
  • the exhaust gases flow via the Bypass device 16 further into an exhaust pipe 20 into the atmosphere or a further exhaust system, not shown.
  • the bypass device 16 is designed in the form of a rotary slide valve or roller control valve with a housing 21.
  • the housing 21 has a tubular channel inserted therein
  • the housing 21 has an opening 24 to the bypass line 15, an opening 25 to the exhaust line 17 and an opening 26 to the exhaust line 20.
  • the rotor 23 in the channel 22 allows either the bypass line 15 or the exhaust line 17 to communicate with the exhaust line 20 via the channel 22 or to establish a connection.
  • the rotor 23 is designed such that, in a position according to FIG. 3, both the bypass line 15 and the exhaust line 17 are closed together by covering the openings 24 and 25 by means of the rotor 23. 2, the bypass line 15 is closed and the exhaust line 17 is completely open. In a position according to FIG. 4, the bypass line 15 is completely open and the exhaust line 17 is closed. 5, the bypass line 15 is partially open and the exhaust line 17 is closed.
  • the rotor 23 is preferably designed as a rod element with a circular cross-sectional cross section, which has a circular cutting angle of 120 ° to 140 °. It is also conceivable to have a rotor 23 which has two cross-sectional cross-sections which are arranged one above the other in the longitudinal direction of a rotor axis of rotation.
  • the two circular section-shaped cross sections can have different circular section angles and, depending on the position of the openings 23, 24 or 25 in the housing 21 to be closed, opened or partially opened, are at any angle to one another.
  • the rotary slide valve 16 is designed such that the rotor 23 when one of the openings 24 and 25 is completely covered, seals them gas-tight.
  • the actuator 23 can be rotated electrically, pneumatically or hydraulically by an actuating device, not shown, which engages the rotor 23 and lies outside the rotary slide valve 16.
  • An electric servomotor is preferably provided for this.
  • the advantage of using a rotary slide valve 16 is its gas tightness when the rotor 23 is completely covered with the openings 24 and 25 to the lines 15 and 17 and the low actuation forces even at high exhaust gas pressures.
  • the internal combustion engine 1 sucks in the air pre-compressed by the compressor 6 from the intake tract 9.
  • the pre-compressed air is compressed further and the compressed air is mixed with fuel (diesel) or an already existing fuel-air mixture is compressed (Otto).
  • the exhaust gas resulting from the combustion of the fuel-air mixture flows through the exhaust gas turbine 5 without its flow being influenced by the radial guide vane 11.
  • the exhaust gas turbine 5 drives the compressor 6 by means of a common shaft 7.
  • the rotor 23 of the rotary slide valve 16 closes the bypass line 15 and opens the exhaust gas line 17, so that the exhaust gas flows completely through the power turbine 4.
  • the power turbine 4 can absorb the remaining energy of the exhaust gas and then supply it to the internal combustion engine 1 by means of the transmission 10.
  • the internal combustion engine 1 draws in pre-compressed air from the intake tract 8.
  • the internal combustion engine 1 compresses the air and, on the other hand, does not mix the compressed air with fuel, so that no combustion can take place.
  • the engine control unit 12 opens the constant throttle 2 in the respective cylinders via the control line 19 in order to to let compressed air escape from the internal combustion engine 1 into the exhaust tract 8.
  • the constant throttle valve 2 is designed as an additional throttle valve in the cylinder head, which can be opened continuously during engine braking.
  • the throttle valve opens or closes a bypass around an exhaust valve of a cylinder of the internal combustion engine 1, so that compressed air enters the exhaust tract 8.
  • the braking power of the internal combustion engine 1 arises from the power which the internal combustion engine 1 applies in order to compress the intake air, but does not get it back by decompression of the compressed air.
  • the engine control unit 12 additionally controls the rotary slide valve 16 and the radial guide vane 11 as a function of the speed of the internal combustion engine 1.
  • the constant throttle valve 2 interacts with the rotary slide valve 16 in such a way that the constant throttle valve 2 is opened and the rotor 23 closes the bypass line 15 and the exhaust gas line 17 equally gas-tight (FIG. 3).
  • This increases the pumping power or engine braking power of the internal combustion engine 1, since the pistons have to perform a higher push-out work in the fourth work cycle (extension cycle) due to the higher exhaust gas back pressure in the exhaust system 8.
  • the constant throttle valve 2 interacts with the radial guide vane 11 and the rotary slide valve 16 such that the constant throttle 2 is open and the radial guide vane 11 changes an effective turbine cross section such that the speed of the exhaust gas turbine 5 increases.
  • This increases the boost pressure and thus the filling of the cylinders and ultimately the compression work in engine braking.
  • the rotor 23 closes the exhaust pipe 17 and opens the Bypass line 15 completely (FIG. 4) or only partially (FIG. 5), the bypass line 15 and the exhaust line 20 being connected to one another via the channel 22 of the rotary slide valve 16.
  • the exhaust gas flows through the bypass line 15 past the utility turbine 4.
  • the exhaust gas counterpressure after the exhaust gas turbine 5 drops and the increased pressure difference at the exhaust gas turbine 5 increases the speed of the exhaust gas turbine 5.
  • this leads to an additional boost pressure increase and thus to an increase in the engine braking power.
  • the exhaust back pressure after the exhaust gas turbine 5 can be increased by partially closing the bypass line 15 by means of the rotary slide valve 16, which leads to a reduction in the pressure difference at the exhaust gas turbine 5 and leads to a decrease in the speed of the exhaust gas turbocharger 3.
  • a characteristic curve for controlling the constant throttle 2, the radial guide vane 11 and the rotary slide valve 16 is stored in the engine control unit 12.
  • the characteristic curve was previously determined in test bench tests depending on the exhaust gas temperature of the internal combustion engine 1 and the speed of the exhaust gas turbocharger 3.
  • the transition point is determined at a medium speed at which the constant throttle 2 interacts with the rotary slide valve 16 or with the radial guide vane 11 and the rotary slide valve 16.
  • the transition point at a medium speed depends on a maximum permissible exhaust gas temperature and / or indicated work in engine braking mode from the high and low

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Supercharger (AREA)
  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

Disclosed is an internal combustion engine (1) comprising an engine braking mechanism, especially in the form of a constant throttle valve, an exhaust gas turbocharger (3), a variable turbine geometry (11), and an effective turbine (4). The exhaust gas turbine (5) is associated with an exhaust manifold (8) while the compressor (6) is allocated to an intake manifold (9) of the internal combustion engine (1). The effective turbine (4) is mounted downstream of the exhaust gas turbine (5) of the exhaust gas turbocharger (3) and is driven by means of the exhaust gas of the internal combustion engine (1). The effective turbine (4) is preferably coupled to the internal combustion engine (1) via a transmission (10). A bypass device (16) which is connected to the effective turbine (4) via an exhaust gas pipe (14) is provided in a bypass conduit (15) around the effective turbine (4). The inventive bypass device (16) is embodied in the form of a rotary slide valve and is used for air-compressing or mixture-compressing internal combustion engines comprising an engine braking mechanism.

Description

Brennkraftmaschine mit einer Motorbremseinrichtung Internal combustion engine with an engine brake device
Die Erfindung betrifft eine Brennkraftmaschine mit einer Motorbremseinrichtung nach dem Oberbegriff des Anspruchs 1.The invention relates to an internal combustion engine with an engine brake device according to the preamble of claim 1.
Aus der Patentschrift EP 0 477 579 Bl ist eine gattungsgemäße Brennkraftmaschine mit einer Motorbremseinrichtung in Form einer Kompressionsbremse bekannt . Die Brennkraftmaschine weist einen Abgasturbolader auf, dessen Abgasturbine in einem Abgastrakt und dessen Verdichter in einem Ansaugtrakt der Brennkraftmaschine vorgesehen sind. Stromab der Abgasturbine ist eine vom Abgas der Brennkraftmaschine angetriebene und mit der Brennkraftmaschine über ein Getriebe gekoppelte Nutzturbine vorgesehen. In einer Abgasleitung stromab der Nutzturbine ist eine Bypasseinrichtung vorgesehen, die es erlaubt, eine Bypassleitung um die Nutzturbine herum zu öffnen oder zu schließen. Die Bypasseinrichtung ist als variables Schaltventil in Form eines Klappenventils ausgeführt . Das Abgas der Brennkraftmaschine treibt die Abgasturbine an, die über eine gemeinsame Welle den Verdichter antreibt. Der Verdichter saugt Luft an und befördert die verdichtete Luft in den Ansaugtrakt der Brennkraftmaschine . Das Abgas der Brennkraf maschine strömt zunächst in die Abgasturbine des Abgasturboladers und dann weiter in die Nutzturbine, die die restliche Energie im Abgas über das Getriebe an die Brennkraftmaschine wieder zuführt . Im Motorbremsbetrieb ist die Kraftstoffeinspritzung deaktiviert und die Kompressionsbremse aktiviert. Die Kompressionsbremse öffnet am Ende eines Verdichtungstaktes mindestens ein am Zylinderkopf vorgesehenes Auslassventil für einen kurzen Zeitraum. Die komprimierte Luft im Brennraum entweicht bei offenem Auslassventil dann in den Abgastrakt . Die Brennkraftmaschine leistet nur Kompressionsarbeit und erzeugt dadurch eine Bremsleistung. Die Kompressionsarbeit ist abhängig vom Füllungsgrad der Zylinder. Um einen hohen Füllungsgrad zu erreichen, muss der Abgasgegendruck nach der Abgasturbine gering sein. Die Nutzturbine stromab der Abgasturbine stellt eine Drossel dar, die den Abgasgegendruck erhöht . Außerdem treibt die vom Abgas angetriebene Nutzturbine die Brennkraftmaschine an. Um den Abgasgegendruck zu senken und die Nutzturbine nicht anzutreiben, öffnet die Bypasseinrichtung. Das Abgas strömt in die Bypassleitung an der Nutzturbine vorbei. Die von einer getakteten Kompressionsbremse erzeugte Bremsleistung zeigt über der Drehzahl einen flachen, etwa linearen Verlauf. Dies bedeutet, dass bei niedrigen bis mittleren Drehzahlen die Bremsleistung gering ist .From the patent EP 0 477 579 B1 a generic internal combustion engine with an engine brake device in the form of a compression brake is known. The internal combustion engine has an exhaust gas turbocharger, the exhaust gas turbine of which is provided in an exhaust tract and the compressor of which is provided in an intake tract of the internal combustion engine. Downstream of the exhaust gas turbine there is a utility turbine driven by the exhaust gas of the internal combustion engine and coupled to the internal combustion engine via a transmission. A bypass device is provided in an exhaust gas line downstream of the utility turbine, which allows a bypass line to be opened or closed around the utility turbine. The bypass device is designed as a variable switching valve in the form of a flap valve. The exhaust gas from the internal combustion engine drives the exhaust gas turbine, which drives the compressor via a common shaft. The compressor sucks in air and conveys the compressed air into the intake tract of the internal combustion engine. The exhaust gas from the internal combustion engine first flows into the exhaust gas turbine of the exhaust gas turbocharger and then further into the utility turbine, which feeds the remaining energy in the exhaust gas back to the internal combustion engine via the transmission. In engine braking mode, fuel injection is deactivated and the compression brake is activated. At the end of a compression stroke, the compression brake opens at least one exhaust valve provided on the cylinder head for a short period of time. The compressed air in the combustion chamber then escapes into the exhaust tract when the exhaust valve is open. The internal combustion engine only performs compression work and thereby generates braking power. The compression work depends on the degree of filling of the cylinders. In order to achieve a high degree of filling, the exhaust gas back pressure after the exhaust gas turbine must be low. The utility turbine downstream of the exhaust gas turbine represents a throttle that increases the exhaust gas back pressure. In addition, the utility turbine driven by the exhaust gas drives the internal combustion engine. The bypass device opens in order to reduce the exhaust gas back pressure and not drive the power turbine. The exhaust gas flows into the bypass line past the utility turbine. The braking power generated by a clocked compression brake shows a flat, approximately linear course over the speed. This means that the braking power is low at low to medium speeds.
Aufgabe der Erfindung ist es demgegenüber, eine Brennkraftmaschine der eingangs genannten Art zur Verfügung zu stellen, deren Bremsleistung bei niedrigen und mittleren Drehzahlen der Brennkraftmaschine deutlich erhöht ist. Vorteilhafterweise ergibt sich ein ansteigender Verlauf der Bremsleistung auch bei mittleren bis hohen Drehzahlen der Brennkraftmaschine .In contrast, the object of the invention is to provide an internal combustion engine of the type mentioned at the beginning, the braking power of which is significantly increased at low and medium engine speeds. Advantageously, the braking power increases, even at medium to high engine speeds.
Diese Aufgabe wird durch eine Brennkraftmaschine mit den Merkmalen des Anspruchs 1 gelöst .This object is achieved by an internal combustion engine with the features of claim 1.
Die erfindungsgemäße Brennkraftmaschine ist gekennzeichnet durch die Bypasseinrichtung, die in Form eines kombinierten Schalt- und Drosselventils ausgeführt ist, so dass die Abgasleitung vollständig und die Bypassleitung vollständig oder teilweise schließbar ist. An der Brennkraftmaschine mit einer Motorbremseinrichtung in Form einer Kompressionsbremse sind ein Abgasturbolader und eine Nutzturbine vorgesehen. Der Abgasturbolader weist eine Abgasturbine auf, die einen Abgastrakt und einen Verdichter, der einen Ansaugtrakt zugeordnet sind. Die Nutzturbine ist stromab der Abgasturbine angeordnet und über ein Getriebe mit der Brennkraftmaschine gekoppelt. Die Abgasturbine und die Nutzturbine sind über eine Verbindungsleitung miteinander verbunden. Von der Verbindungsleitung zweigt eine Bypassleitung ab. In der Bypassleitung um die Nutzturbine herum ist die Bypasseinrichtung vorgesehen. Die Bypasseinrichtung steuert die Menge des bypassierten Abgases um die Nutzturbine herum. Neben der Steuerung der Abgasmenge in der Bypassleitung, öffnet oder schließt die Bypasseinrichtung die Abgasleitung, die von der Nutzturbine zu der Bypasseinrichtung führt. Der Vorteil dieser Anordnung ist, dass ein Schaltventil und ein Drosselventil in einem gemeinsamen Bauteil, der Bypasseinrichtung kombiniert sind.The internal combustion engine according to the invention is characterized by the bypass device, which is designed in the form of a combined switching and throttle valve, so that the exhaust line can be closed completely and the bypass line completely or partially. An exhaust gas turbocharger and a power turbine are provided on the internal combustion engine with an engine brake device in the form of a compression brake. The exhaust gas turbocharger has an exhaust gas turbine which has an exhaust tract and a compressor which is assigned to an intake tract. The utility turbine is downstream of the exhaust gas turbine arranged and coupled via a gearbox to the internal combustion engine. The exhaust gas turbine and the power turbine are connected to one another via a connecting line. A bypass line branches off from the connecting line. The bypass device is provided in the bypass line around the utility turbine. The bypass device controls the amount of bypassed exhaust gas around the utility turbine. In addition to controlling the amount of exhaust gas in the bypass line, the bypass device opens or closes the exhaust line, which leads from the utility turbine to the bypass device. The advantage of this arrangement is that a switching valve and a throttle valve are combined in a common component, the bypass device.
In Ausgestaltung der Erfindung ist die Bypasseinrichtung so ausgeführt, dass bei vollständigen Schließen der Abgasleitung und der Bypassleitung durch die Bypasseinrichtung, diese gasdicht geschlossen werden können. Um einen möglichst hohen Wirkungsgrad im Verbrennungsbetrieb oder im Motorbremsbetrieb der Brennkraftmaschine zu erreichen, ist es nötig der Abgasstrom genau zu steuern bzw. zu regeln. Beispielsweise würde bei einer nicht gasdicht geschlossenen Bypassleitung im Verbrennungsbetrieb Abgasesenergie verloren gehen, da diese der über die geöffnete Abgasleitung mit Abgas angetriebene Nutzturbine nicht mehr zur Verfügung steht.In an embodiment of the invention, the bypass device is designed such that when the exhaust line and the bypass line are completely closed by the bypass device, they can be closed gas-tight. In order to achieve the highest possible efficiency in the combustion mode or in the engine braking mode of the internal combustion engine, it is necessary to precisely control or regulate the exhaust gas flow. For example, exhaust gas energy would be lost in a combustion mode in a bypass line which is not closed in a gas-tight manner, since this is no longer available to the utility turbine driven by exhaust gas via the open exhaust line.
In Ausgestaltung der Erfindung ist die Bypasseinrichtung in Form eines Drehschieberventils ausgeführt. Der Vorteil der Verwendung eines Drehschiebers als Bypasseinrichtung liegt in den geringen Betätigungskräften selbst bei hohen Abgasdrücken .In an embodiment of the invention, the bypass device is designed in the form of a rotary slide valve. The advantage of using a rotary valve as a bypass device lies in the low actuation forces even at high exhaust gas pressures.
In weiterer Ausgestaltung der Erfindung weist das Drehschieberventil ein Gehäuse mit einem darin eingebrachten rohrförmigen Kanal auf, in dem ein frei drehbarer Rotor gelagert ist, der mit einem kreisausschnittsfδrmigen Querschnitt ausgeführt ist. Das Gehäuse weist eine Öffnung zu der Abgasleitung, eine Öffnung zu der Bypassleitung und eine Öffnung zur einer Abgasleitung, durch die das Abgas in die Atmosphäre oder eine Abgasanlage strömen kann, auf. Der Kanal erlaubt es der Abgasleitung und der Bypassleitung mit der Abgasleitung zu kommunizieren bzw. eine Verbindung herzustellen. Der kreisausschnittsförmige Querschnitt des Rotors ist so gewählt, dass der Rotor entweder die Abgasleitung und den Bypasskanal oder nur die Abgasleitung oder die Abgasleitung vollständig und die Bypassleitung teilweise verschließen kann. Der Vorteil liegt in dem einfachen, druckunempfindlichen und gasdichten Aufbau selbst bei hohen Abgasdrücken.In a further embodiment of the invention, the rotary slide valve has a housing with a tubular channel inserted therein, in which a freely rotatable rotor is mounted, which is designed with a cross section in the form of a circular section. The housing has an opening the exhaust line, an opening to the bypass line and an opening to an exhaust line through which the exhaust gas can flow into the atmosphere or an exhaust system. The channel allows the exhaust line and the bypass line to communicate with the exhaust line or to establish a connection. The circular cross-section of the rotor is selected so that the rotor can either completely close the exhaust line and the bypass channel or only the exhaust line or the exhaust line and partially close the bypass line. The advantage lies in the simple, pressure-insensitive and gas-tight construction even at high exhaust gas pressures.
In weiterer Ausgestaltung der Erfindung weist der kreisausschnittsförmige Querschnitt des Rotors einen Kreisausschnittswinkel von 120° bis 140° auf. Durch die Wahl dieses Kreisausschnittswinkels kann ein flacher, bauraumsparender Aufbau des Gehäuses und der angeschlossenen Leitungen realisiert werden.In a further embodiment of the invention, the circular section-shaped cross section of the rotor has a circular section angle of 120 ° to 140 °. By choosing this circular cutout angle, a flat, space-saving construction of the housing and the connected lines can be realized.
In weiterer Ausgestaltung der Erfindung öffnet die Kompressionsbremse im Motorbremsbetrieb und die Bypasseinrichtung schließt im Motorbremsbetrieb bei niedrigen bis mittleren Drehzahlen der Brennkraftmaschine die Abgasleitung und die Bypassleitung. Die Kompressionsbremse ist vorzugsweise in Form einer bekannten Konstantdrossel ausgeführt . Die Konstantdrossei ist als ein zusätzliches Drosselventil im Zylinderkopf ausgeführt, das sich im Motorbremsbetrieb kontinuierlich öffnen lässt. Das Drosselventil öffnet oder schließt einen Bypass um ein Auslassventil eines Zylinders der Brennkraftmaschine herum, so dass komprimierte Luft in den Abgastrakt gelangt. Im Motorbremsbetrieb öffnet die Konstantdrossel und setzt zumindest einen Teil der Kompressionsarbeit frei . Außerdem schließt im Motorbremsbetrieb die Bypasseinrichtung die Abgasleitung und die Bypassleitung. Dadurch erhöht sich zusätzlich die Pumpleistung der Brennkraftmaschine. Der Vorteil der Verwendung einer Konstantdrossei mit der Bypasseinrichtung als Staubremse liegt in der erhöhten Bremsleistung bei niedrigen bis mittleren Drehzahlen der Brennkraftmaschine. Außerdem kann auf eine Bremsklappe im Abgassystem verzichtet werden.In a further embodiment of the invention, the compression brake opens in the engine brake mode and the bypass device closes the exhaust line and the bypass line in the engine brake mode at low to medium engine speeds. The compression brake is preferably designed in the form of a known constant throttle. The constant throttle egg is designed as an additional throttle valve in the cylinder head, which can be opened continuously during engine braking. The throttle valve opens or closes a bypass around an exhaust valve of a cylinder of the internal combustion engine, so that compressed air gets into the exhaust tract. During engine braking, the constant throttle opens and releases at least part of the compression work. In addition, the bypass device closes the exhaust line and the bypass line in engine braking mode. This also increases the pumping power of the internal combustion engine. The The advantage of using a constant throttle with the bypass device as a dust brake is the increased braking power at low to medium engine speeds. There is also no need for a brake flap in the exhaust system.
In weiterer Ausgestaltung der Erfindung öffnet die Kompressionsbremse im Motorbremsbetrieb und die Abgasturbine, die über eine variable Turbinengeometrie verfügt, die im Motorbremsbetrieb die Strömung des Abgases auf ein Turbinenrad so verändert, dass im Motorbremsbetrieb bei mittleren bis hohen Drehzahlen der Brennkraftmaschine eine Erhöhung der Drehzahl der Abgasturbine erfolgt, wobei die Bypasseinrichtung die Abgasleitung schließt und die Bypassleitung vollständig öffnet. Die variable Turbinengeometrie ist als bekanntes Leitgitter ausgeführt, insbesondere als Radialleitgitter mit verstellbaren oder feststehenden Leitschaufeln. Das Radialleitgitter verkleinert im Motorbremsbetrieb einen wirksamen Turbinenquerschnitt, so dass die Geschwindigkeit des Abgases steigt . Dadurch steigt die Drehzahl der Abgasturbine . Durch die Steigerung der Drehzahl der Abgasturbine steigt auch die Drehzahl eines Verdichters, wodurch sich der Ladedruck erhöht. Mit einer Erhöhung des Ladedrucks erhöht sich die Füllung im Zylinder und in Verbindung mit einer Konstantdrossei erhöht sich auch die Bremsleistung. Gleichzeitig verschließt im Motorbremsbetrieb die Bypasseinrichtung die Abgasleitung und öffnet die Bypassleitung. Das Abgas strömt durch die Bypassleitung an der Nutzturbine vorbei. Dadurch sinkt der Abgasgegendruck nach der Abgasturbine. Durch die erhöhte Druckdifferenz steigt die Drehzahl der Abgasturbine. Vorteilhafterweise führt dies zu einer zusätzlichen Ladedruckerhöhung und damit zu einer erhöhten Bremsleistung. Außerdem trägt die Nutzturbine zur Bremsleistung bei, da die Brennkraftmaschine die Nutzturbine antreibt und die Nutzturbine nicht Energie aus dem Abgas an die Brennkraftmaschine abgibt . In weiterer Ausgestaltung der Erfindung öffnet die Kompressionsbremse im Motorbremsbetrieb und die Abgasturbine, die über eine variable Turbinengeometrie verfügt, die im Motorbremsbetrieb die Strömung des Abgases auf ein Turbinenrad so verändert, dass im Motorbremsbetrieb bei hohen bis sehr hohen Drehzahlen der Brennkraftmaschine eine Erhöhung der Drehzahl der Abgasturbine erfolgt, wobei die Bypasseinrichtung die Abgasleitung schließt und die Bypassleitung teilweise schließt. Bei einer Brennkraftmaschine mit einem Abgasturbolader ist der Abgasturbolader für den Verbrennungsbetrieb der Brennkraftmaschine optimal ausgelegt . Im Motorbremsbetrieb kann es daher zum Überschreiten von kritischen Abgasturboladerdrehzahlen kommen, insbesondere wenn eine Abgasturbine eines Abgasturboladers eine variable Turbinengeometrie aufweist. Im Motorbremsbetrieb dient die variable Turbinengeometrie zur Drehzahlsteigerung des Abgasturboladers. Durch Drosselung der Bypassleitung steigt der Abgasgegendruck nach der Abgasturbine, was zu einer Verringerung der Druckdifferenz an der Abgasturbine führt und zu einer Verminderung der Drehzahl des Abgasturboladers bewirkt. Der Vorteil liegt im Wegfall einer drehzahlregulierenden Maßnahme am Abgasturbolader, beispielsweise eines Waste-Gate-Ventils .In a further embodiment of the invention, the compression brake opens in the engine brake mode and the exhaust gas turbine, which has a variable turbine geometry, which changes the flow of the exhaust gas onto a turbine wheel in the engine brake mode so that an increase in the speed of the exhaust gas turbine in the engine brake mode at medium to high engine speeds takes place, the bypass device closes the exhaust line and opens the bypass line completely. The variable turbine geometry is designed as a known guide vane, in particular as a radial guide vane with adjustable or fixed guide vanes. The radial guide grid reduces an effective turbine cross-section when the engine is braking, so that the exhaust gas speed increases. This increases the speed of the exhaust gas turbine. Increasing the speed of the exhaust gas turbine also increases the speed of a compressor, which increases the boost pressure. With an increase in the boost pressure, the filling in the cylinder increases and, in conjunction with a constant throttle, the braking power also increases. At the same time, the bypass device closes the exhaust line and opens the bypass line in engine braking mode. The exhaust gas flows through the bypass line past the utility turbine. This reduces the exhaust gas back pressure after the exhaust gas turbine. The speed of the exhaust gas turbine increases due to the increased pressure difference. This advantageously leads to an additional boost pressure increase and thus to an increased braking power. In addition, the power turbine contributes to the braking power, since the internal combustion engine drives the power turbine and the power turbine does not deliver energy from the exhaust gas to the internal combustion engine. In a further embodiment of the invention, the compression brake opens in the engine brake mode and the exhaust gas turbine, which has a variable turbine geometry, which changes the flow of the exhaust gas onto a turbine wheel in the engine brake mode so that an increase in the speed of the internal combustion engine increases at high to very high engine speeds Exhaust gas turbine takes place, the bypass device closing the exhaust line and partially closing the bypass line. In an internal combustion engine with an exhaust gas turbocharger, the exhaust gas turbocharger is optimally designed for the combustion operation of the internal combustion engine. Critical exhaust gas turbocharger speeds can therefore be exceeded in engine braking operation, in particular if an exhaust gas turbine of an exhaust gas turbocharger has a variable turbine geometry. In engine braking mode, the variable turbine geometry serves to increase the speed of the exhaust gas turbocharger. By throttling the bypass line, the exhaust gas back pressure increases after the exhaust gas turbine, which leads to a reduction in the pressure difference at the exhaust gas turbine and to a reduction in the speed of the exhaust gas turbocharger. The advantage lies in the omission of a speed-regulating measure on the exhaust gas turbocharger, for example a waste gate valve.
In weiterer Ausgestaltung der Erfindung können im Motorbremsbetrieb die Auslassventile der Brennkraftmaschine durch Druckspitzen des Abgases im Abgastrakt kurzzeitig geöffnet werden, wodurch Abgas aus dem Abgastrakt in die Zylinder der Brennkraftmaschine gelangt. Das kurze Öffnen der Auslassventile ist insbesondere bei niedrigen Zylinderdrücken möglich. Dies führt insbesondere am Ende des ersten Arbeitstaktes (Ansaugen) oder zu Beginn des zweiten Arbeitstaktes (Komprimieren) zu einem Nachladeeffekt, bei dem Abgas aus dem Abgastrakt in die Zylinder der Brennkraftmaschine gelangt. Vorteilhafterweise führt der Nachladeeffekt zu einer erhöhten Zylinderfüllung und damit erhöhten Motorbrems1eistung .In a further embodiment of the invention, in engine braking operation, the exhaust valves of the internal combustion engine can be opened briefly by pressure peaks in the exhaust gas in the exhaust tract, as a result of which exhaust gas from the exhaust tract enters the cylinders of the internal combustion engine. It is possible to open the exhaust valves briefly, especially at low cylinder pressures. This leads, particularly at the end of the first work cycle (intake) or at the start of the second work cycle (compression), to a recharging effect in which exhaust gas from the exhaust system travels into the cylinders of the internal combustion engine. The leads advantageously Reloading effect to an increased cylinder charge and thus increased engine braking power.
Weitere Merkmale und Merkmalskombinationen ergeben sich aus der Beschreibung sowie den Zeichnungen. Ein konkretes Ausführungsbeispiel der Erfindung ist in den Zeichnungen vereinfacht dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen:Further features and combinations of features result from the description and the drawings. A specific embodiment of the invention is shown in simplified form in the drawings and explained in more detail in the following description. Show it:
Fig.l eine schematisch vereinfachte Darstellung einer Brennkraftmaschine, die mit einer Motorbremseinrichtung, einem Abgasturbolader und einer Nutzturbine ausgestattet ist,1 shows a schematically simplified illustration of an internal combustion engine which is equipped with an engine brake device, an exhaust gas turbocharger and a utility turbine,
Fig.2 eine schematisch vereinfachte Darstellung des erfindungsgemäßen Drehschieberventils mit offener Abgasleitung und geschlossener Bypassleitung,2 shows a schematically simplified illustration of the rotary slide valve according to the invention with an open exhaust gas line and a closed bypass line,
Fig.3 eine schematisch vereinfachte Darstellung des erfindungsgemäßen Drehschieberventils mit geschlossener Abgasleitung und geschlossener Bypassleitung,3 shows a schematically simplified illustration of the rotary slide valve according to the invention with closed exhaust pipe and closed bypass pipe,
Fig.4 eine schematisch vereinfachte Darstellung des erfindungsgemäßen Drehschieberventils mit geschlossener Abgasleitung und mit geöffneter Bypassleitung und4 shows a schematically simplified illustration of the rotary slide valve according to the invention with the exhaust pipe closed and the bypass pipe open and
Fig.5 eine schematisch vereinfachte Darstellung des erfindungsgemäßen Drehschieberventils mit geschlossener Abgasleitung und mit teilgeöffneter Bypassleitung.5 shows a schematically simplified representation of the rotary slide valve according to the invention with the exhaust gas line closed and with the bypass line partially open.
In Fig. 1 ist schematisch vereinfacht eine Brennkraftmaschine 1 mit mindestens einem Auslassventil pro Zylinder dargestellt, die mit einer Motorbremseinrichtung 2, mit einem Abgasturbolader 3 und einer Nutzturbine 4 ausgestattet ist. Die Motorbremseinrichtung 2 ist in Form einer bekannten Kompressionsbremse vorzugsweise als Konstantdrossei ausgeführt. Zu dem Aufbau und der Wirkungsweise der Konstantdrossei wird beispielhaft auf die DE 197 27 584 Cl verwiesen. Der Abgasturbolader 3 weist eine Abgasturbine 5 und einen Verdichter 6 auf, die über eine gemeinsame Welle 7 miteinander verbunden sind. Die Abgasturbine 5 ist einem Abgastrakt 8 und der Verdichter 6 ist einem Ansaugtrakt 9 der Brennkraftmaschine 1 zugeordnet . In dem Ansaugtrakt 9 kann ein nicht näher dargestellter Ladeluft-Kühler eingebracht sein. Die Nutzturbine 4 ist stromab der Abgasturbine 5 vorgesehen und über ein Getriebe 10 an der Brennkraftmaschine 1 gekoppelt. Die Abgasturbine 5 ist mit einer variablen Turbinengeometrie 11 ausgestattet. Die variable Turbinengeometrie 11 ist als Radialleitgitter mit verstellbaren oder feststehenden Leitschaufeln ausgeführt. Mit Hilfe des Radialleitgitters 11 ist die Abgasströmung vor einem Turbinenrad auf die Schaufeln des Turbinenrades der Abgasturbine 5 veränderbar. Durch eine nicht näher dargestellte Betätigungseinrichtung, die an dem Radialleitgitter 10 angreift und außerhalb eines Gehäuses der Abgasturbine 5 liegt, kann das Radialleitgitter 11 elektrisch, pneumatisch oder hydraulisch betätigt werden. Die Steuerung der Betätigungseinrichtung erfolgt mittels eines elektronischen Motorsteuergerätes 12, das über eine erste Steuerleitung 13 mit der Betätigungseinrichtung verbunden ist. Die Abgasturbine 5 und die Nutzturbine 4 sind über eine Verbindungsleitung 14 miteinander verbunden. Von der Verbindungsleitung 14 zweigt eine Bypassleitung 15 ab. In der Bypassleitung 15 um die Nutzturbine 4 herum ist eine Bypasseinrichtung 16 vorgesehen. Die Bypasseinrichtung 16 steuert die Menge des bypassierten Abgases um die Nutzturbine 4 herum. Neben der Steuerung der Abgasmenge in der Bypassleitung 15, öffnet oder schließt die Bypasseinrichtung 16 eine Abgasleitung 17, die von der Nutzturbine 4 zu der Bypasseinrichtung 16 führt. Die Steuerung der Bypasseinrichtung 16 erfolgt mittels des Motorsteuergerätes 12 über eine zweite Steuerleitungen 18. Außerdem steuert das Motorsteuergerät 12 über eine dritte Steuerleitung 19 die Konstantdrossel 2. Die Abgase strömen über die Bypasseinrichtung 16 weiter in eine Abgasleitung 20 in die Atmosphäre oder eine nicht näher dargestellte, weiterführende Abgasanläge .1 schematically shows an internal combustion engine 1 with at least one exhaust valve per cylinder, which is equipped with an engine brake device 2, with an exhaust gas turbocharger 3 and a power turbine 4. The engine brake device 2 is preferably designed as a constant throttle in the form of a known compression brake. On the structure and mode of operation of the Konstantdrossei is referred to DE 197 27 584 Cl as an example. The exhaust gas turbocharger 3 has an exhaust gas turbine 5 and a compressor 6, which are connected to one another via a common shaft 7. The exhaust gas turbine 5 is assigned to an exhaust tract 8 and the compressor 6 is assigned to an intake tract 9 of the internal combustion engine 1. A charge air cooler (not shown in detail) can be introduced in the intake tract 9. The utility turbine 4 is provided downstream of the exhaust gas turbine 5 and is coupled to the internal combustion engine 1 via a transmission 10. The exhaust gas turbine 5 is equipped with a variable turbine geometry 11. The variable turbine geometry 11 is designed as a radial guide vane with adjustable or fixed guide vanes. With the help of the radial guide vane 11, the exhaust gas flow in front of a turbine wheel on the blades of the turbine wheel of the exhaust gas turbine 5 can be changed. The radial guide grill 11 can be actuated electrically, pneumatically or hydraulically by an actuating device, not shown in more detail, which engages the radial guide grill 10 and is located outside a housing of the exhaust gas turbine 5. The actuation device is controlled by means of an electronic engine control unit 12, which is connected to the actuation device via a first control line 13. The exhaust gas turbine 5 and the power turbine 4 are connected to one another via a connecting line 14. A bypass line 15 branches off from the connecting line 14. A bypass device 16 is provided in the bypass line 15 around the utility turbine 4. The bypass device 16 controls the amount of bypassed exhaust gas around the power turbine 4. In addition to controlling the amount of exhaust gas in the bypass line 15, the bypass device 16 opens or closes an exhaust line 17 which leads from the power turbine 4 to the bypass device 16. The bypass device 16 is controlled by means of the engine control unit 12 via a second control line 18. In addition, the engine control unit 12 controls the constant throttle 2 via a third control line 19. The exhaust gases flow via the Bypass device 16 further into an exhaust pipe 20 into the atmosphere or a further exhaust system, not shown.
Die Fig. 2 bis 5 zeigen eine schematisch, vereinfachte Ausführung der erfindungsgemäßen Bypasseinrichtung 16. Die Bypasseinrichtung 16 ist in Form eines Drehschieberventils bzw. Walzensteuerventils mit einem Gehäuse 21 ausgeführt. Das Gehäuse 21 weist einen darin eingebrachten rohrförmigen Kanal2 to 5 show a schematic, simplified embodiment of the bypass device 16 according to the invention. The bypass device 16 is designed in the form of a rotary slide valve or roller control valve with a housing 21. The housing 21 has a tubular channel inserted therein
22 auf, in dem ein frei drehbarer Rotor 23 gelagert ist. Das Gehäuse 21 weist eine Öffnung 24 zu der Bypassleitung 15, eine Öffnung 25 zu der Abgasleitung 17 und eine Öffnung 26 zu der Abgasleitung 20 auf. Der Rotor 23 in dem Kanal 22 erlaubt es wahlweise der Bypassleitung 15 oder der Abgasleitung 17 über den Kanal 22 mit der Abgasleitung 20 zu kommunizieren bzw. eine Verbindung herzustellen. Die Gestaltung des Rotors22 in which a freely rotatable rotor 23 is mounted. The housing 21 has an opening 24 to the bypass line 15, an opening 25 to the exhaust line 17 and an opening 26 to the exhaust line 20. The rotor 23 in the channel 22 allows either the bypass line 15 or the exhaust line 17 to communicate with the exhaust line 20 via the channel 22 or to establish a connection. The design of the rotor
23 ist so ausgeführt, dass in einer Stellung gemäß Fig. 3 sowohl die Bypassleitung 15 als auch die Abgasleitung 17 durch Überdeckung der Öffnungen 24 und 25 mittels des Rotors 23 gemeinsam geschlossen sind. In einer Stellung gemäß Fig. 2 ist die Bypassleitung 15 geschlossen und die Abgasleitung 17 vollständig geöffnet. In einer Stellung gemäß Fig. 4 ist die Bypassleitung 15 vollständig geöffnet und die Abgasleitung 17 geschlossen. In einer Stellung gemäß Fig. 5 ist die Bypassleitung 15 teilweise geöffnet und die Abgasleitung 17 geschlossen. Der Rotor 23 ist vorzugsweise als ein Stangenelement mit einem kreisausschnittsförmigen Querschnitt ausgeführt, der einen Kreisausschnittswinkel von 120° bis 140° aufweist. Denkbar ist auch ein Rotor 23 der zwei kreisausschnittsförmige Querschnitte mit besitzt, die in Längsrichtung einer Rotordrehachse übereinander angeordnet sind. Die zwei kreisausschnittsförmige Querschnitte können unterschiedliche Kreisausschnittswinkel besitzen und entsprechend der Lage der zu verschliessenden, zu öffnenden oder teilweise zu öffnenden Öffnungen 23, 24 oder 25 im Gehäuse 21 in einem beliebigen Winkel zueinander stehen. Das Drehschieberventil 16 ist so ausgeführt, dass der Rotor 23 bei voller Überdeckung einer der Öffnungen 24 und 25, diese gasdicht verschließt. Durch eine nicht näher dargestellte Betätigungseinrichtung, die an dem Rotor 23 angreift und außerhalb des Drehschieberventils 16 liegt, kann der Rotor 23 elektrisch, pneumatisch oder hydraulisch gedreht werden. Vorzugsweise ist hierzu ein elektrischer Stellmotor vorgesehen. Der Vorteil der Verwendung eines Drehschieberventils 16 liegt seiner Gasdichtheit bei voller Überdeckung des Rotors 23 mit den Öffnungen 24 bzw. 25 zu den Leitungen 15 bzw. 17 und den geringen Betätigungskräften selbst bei hohen Abgasdrücken.23 is designed such that, in a position according to FIG. 3, both the bypass line 15 and the exhaust line 17 are closed together by covering the openings 24 and 25 by means of the rotor 23. 2, the bypass line 15 is closed and the exhaust line 17 is completely open. In a position according to FIG. 4, the bypass line 15 is completely open and the exhaust line 17 is closed. 5, the bypass line 15 is partially open and the exhaust line 17 is closed. The rotor 23 is preferably designed as a rod element with a circular cross-sectional cross section, which has a circular cutting angle of 120 ° to 140 °. It is also conceivable to have a rotor 23 which has two cross-sectional cross-sections which are arranged one above the other in the longitudinal direction of a rotor axis of rotation. The two circular section-shaped cross sections can have different circular section angles and, depending on the position of the openings 23, 24 or 25 in the housing 21 to be closed, opened or partially opened, are at any angle to one another. The rotary slide valve 16 is designed such that the rotor 23 when one of the openings 24 and 25 is completely covered, seals them gas-tight. The actuator 23 can be rotated electrically, pneumatically or hydraulically by an actuating device, not shown, which engages the rotor 23 and lies outside the rotary slide valve 16. An electric servomotor is preferably provided for this. The advantage of using a rotary slide valve 16 is its gas tightness when the rotor 23 is completely covered with the openings 24 and 25 to the lines 15 and 17 and the low actuation forces even at high exhaust gas pressures.
Im Verbrennungsbetrieb saugt die Brennkraftmaschine 1 die durch den Verdichter 6 vorverdichtete Luft aus dem Ansaugtrakt 9 an. In den Zylindern der Brennkraftmaschine 1 wird die vorverdichtete Luft weiter komprimiert und die komprimierte Luft mit Kraftstoff vermischt (Diesel) oder es wird ein bereits vorhandenes Kraftstoff-Luft-Gemisch komprimiert (Otto) . Das durch die Verbrennung des Kraftstoff- Luft-Gemisches entstehende Abgas strömt durch die Abgasturbine 5 ohne in seiner Strömung von dem Radialleitgitter 11 beeinflusst zu werden. Die Abgasturbine 5 treibt mittels einer gemeinsamen Welle 7 den Verdichter 6 an. Wie in Fig. 2 dargestellt, schließt der Rotor 23 des Drehschieberventils 16 die Bypassleitung 15 und öffnet die Abgasleitung 17, so dass das Abgas vollständig durch die Nutzturbine 4 strömt. Die Nutzturbine 4 kann die restliche Energie des Abgases aufnehmen und sie anschließend mittels des Getriebes 10 der Brennkraftmaschine 1 zuführen.In the combustion mode, the internal combustion engine 1 sucks in the air pre-compressed by the compressor 6 from the intake tract 9. In the cylinders of the internal combustion engine 1, the pre-compressed air is compressed further and the compressed air is mixed with fuel (diesel) or an already existing fuel-air mixture is compressed (Otto). The exhaust gas resulting from the combustion of the fuel-air mixture flows through the exhaust gas turbine 5 without its flow being influenced by the radial guide vane 11. The exhaust gas turbine 5 drives the compressor 6 by means of a common shaft 7. As shown in FIG. 2, the rotor 23 of the rotary slide valve 16 closes the bypass line 15 and opens the exhaust gas line 17, so that the exhaust gas flows completely through the power turbine 4. The power turbine 4 can absorb the remaining energy of the exhaust gas and then supply it to the internal combustion engine 1 by means of the transmission 10.
Im Motorbremsbetrieb saugt die Brennkraftmaschine 1 vorverdichtete Luft aus dem Ansaugtrakt 8 an. Die Brennkraftmaschine 1 komprimiert die Luft und vermischt die komprimierte Luft hingegen nicht mit Kraftstoff, so dass keine Verbrennung stattfinden kann. Stattdessen öffnet die Motorsteuereinheit 12 über die Steuerleitung 19 die Konstantdrossel 2 in den jeweiligen Zylindern, um die komprimierte Luft aus der Brennkraftmaschine 1 in den Abgastrakt 8 entweichen zu lassen. Die Konstantdrossei 2 ist als ein zusätzliches Drosselventil im Zylinderkopf ausgeführt, das sich im Motorbremsbetrieb kontinuierlich öffnen lässt. Das Drosselventil öffnet oder schließt einen Bypass um ein Auslassventil eines Zylinders der Brennkraftmaschine 1 herum, so dass komprimierte Luft in den Abgastrakt 8 gelangt.In engine braking mode, the internal combustion engine 1 draws in pre-compressed air from the intake tract 8. The internal combustion engine 1 compresses the air and, on the other hand, does not mix the compressed air with fuel, so that no combustion can take place. Instead, the engine control unit 12 opens the constant throttle 2 in the respective cylinders via the control line 19 in order to to let compressed air escape from the internal combustion engine 1 into the exhaust tract 8. The constant throttle valve 2 is designed as an additional throttle valve in the cylinder head, which can be opened continuously during engine braking. The throttle valve opens or closes a bypass around an exhaust valve of a cylinder of the internal combustion engine 1, so that compressed air enters the exhaust tract 8.
Die Bremsleistung der Brennkraftmaschine 1 entsteht durch die Leistung, welche die Brennkraftmaschine 1 aufbringt, um die angesaugte Luft zu komprimieren, aber nicht durch Dekompression der komprimierten Luft zurückerhält. Um im Motorbremsbetrieb die Bremsleistung weiter zu steigern, steuert das Motorsteuergerät 12 in Abhängigkeit der Drehzahl der Brennkraftmaschine 1 zusätzlich das Drehschieberventil 16 und das Radialleitgitter 11 an.The braking power of the internal combustion engine 1 arises from the power which the internal combustion engine 1 applies in order to compress the intake air, but does not get it back by decompression of the compressed air. In order to further increase the braking power in engine braking operation, the engine control unit 12 additionally controls the rotary slide valve 16 and the radial guide vane 11 as a function of the speed of the internal combustion engine 1.
Bei niedrigen bis mittleren Drehzahlen der Brennkraftmaschine 1 wirkt die Konstantdrossei 2 mit dem Drehschieberventil 16 so zusammen, dass die Konstantdrossei 2 geöffnet ist und der Rotor 23 die Bypassleitung 15 und die Abgasleitung 17 beide gleichermaßen gasdicht schließt (Fig. 3) . Dadurch erhöht sich die Pumpleistung bzw. Motorbremsleistung der Brennkraftmaschine 1, da die Kolben im vierten Arbeitstakt (Ausschubtakt) auf Grund des höheren Abgasgegendruckes in dem Abgastrakt 8 eine höhere Ausschiebearbeit leisten muss .At low to medium speeds of the internal combustion engine 1, the constant throttle valve 2 interacts with the rotary slide valve 16 in such a way that the constant throttle valve 2 is opened and the rotor 23 closes the bypass line 15 and the exhaust gas line 17 equally gas-tight (FIG. 3). This increases the pumping power or engine braking power of the internal combustion engine 1, since the pistons have to perform a higher push-out work in the fourth work cycle (extension cycle) due to the higher exhaust gas back pressure in the exhaust system 8.
Bei mittleren bis hohen Drehzahlen der Brennkraftmaschine 1 wirkt die Konstantdrossei 2 mit dem Radialleitgitter 11 und dem Drehschieberventil 16 so zusammen, dass die Konstantdrossel 2 geöffnet ist und das Radialleitgitter 11 einen wirksamen Turbinenquerschnitt so verändert, dass die Drehzahl der Abgasturbine 5 steigt. Dadurch erhöht sich der Ladedruck und damit die Füllung der Zylinder und schließlich die Kompressionsarbeit im Motorbremsbetrieb. Der Rotor 23 schließt dabei die Abgasleitung 17 und öffnet die Bypassleitung 15 vollständig (Fig. 4) oder auch nur teilweise (Fig. 5) , wobei die Bypassleitung 15 und die Abgasleitung 20 über den Kanal 22 des Drehschieberventils 16 miteinander verbunden sind. Das Abgas strömt durch die Bypassleitung 15 an der Nutzturbine 4 vorbei. Dadurch sinkt der Abgasgegendruck nach der Abgasturbine 5 und durch die erhöhte Druckdifferenz an der Abgasturbine 5 steigt die Drehzahl der Abgasturbine 5. Vorteilhafterweise führt dies zu einer zusätzlichen Ladedruckerhöhung und damit zu einer Erhöhung der Motorbremsleistung. Um ein Überschreiten von kritischen Drehzahlen des Abgasturboladers 3 bei hohen bis sehr hohen Drehzahlen der Brennkraftmaschine 1 zu vermeiden, kann durch teilweises Schließen der Bypassleitung 15 mittels des Drehschieberventils 16 der Abgasgegendruck nach der Abgasturbine 5 erhöht werden, was zu einer Verringerung der Druckdifferenz an der Abgasturbine 5 und zu einem Absinken der Drehzahl des Abgasturboladers 3 führt .At medium to high speeds of the internal combustion engine 1, the constant throttle valve 2 interacts with the radial guide vane 11 and the rotary slide valve 16 such that the constant throttle 2 is open and the radial guide vane 11 changes an effective turbine cross section such that the speed of the exhaust gas turbine 5 increases. This increases the boost pressure and thus the filling of the cylinders and ultimately the compression work in engine braking. The rotor 23 closes the exhaust pipe 17 and opens the Bypass line 15 completely (FIG. 4) or only partially (FIG. 5), the bypass line 15 and the exhaust line 20 being connected to one another via the channel 22 of the rotary slide valve 16. The exhaust gas flows through the bypass line 15 past the utility turbine 4. As a result, the exhaust gas counterpressure after the exhaust gas turbine 5 drops and the increased pressure difference at the exhaust gas turbine 5 increases the speed of the exhaust gas turbine 5. Advantageously, this leads to an additional boost pressure increase and thus to an increase in the engine braking power. In order to avoid exceeding critical speeds of the exhaust gas turbocharger 3 at high to very high speeds of the internal combustion engine 1, the exhaust back pressure after the exhaust gas turbine 5 can be increased by partially closing the bypass line 15 by means of the rotary slide valve 16, which leads to a reduction in the pressure difference at the exhaust gas turbine 5 and leads to a decrease in the speed of the exhaust gas turbocharger 3.
Im Motorbremsbetrieb können im Abgastrakt 8 auftretende Druckspitzen des Abgases zu einem kurzen Öffnen der Auslassventile insbesondere bei niedrigen Zylinderdrücken führen. Dies führt insbesondere am Ende des ersten Arbeitstaktes (Ansaugen) oder zu Beginn des zweiten Arbeitstaktes (Komprimieren) zu einem Nachladeeffekt, bei dem Abgas aus dem Abgastrakt 8 in die Zylinder der Brennkraftmaschine 1 gelangt . Der Nachladeeffekt führt zu einer erhöhten Zylinderfüllung und damit erhöhten Motorbremsleistung. Durch schwächere Ventilfedern an den Auslassventilen würden die Auslassventile schon bei niedrigeren Druckspitzen wiederöffnen und die Bremsleistung könnte weiter gesteigert werden. Es muss jedoch gewährleistet sein, dass die Auslassventile im Gaswechsel exakt der Nockenform folgen und es auch bei sehr hohen Drehzahlen der Brennkraftmaschine nicht zu einem Abheben der Auslassventile kommt . Im Motorbremsbetrieb trägt die Nutzturbine 4 zur Bremsleistung bei, da sie von der Brennkraftmaschine 1 mitgeschleppt wird.During engine braking, pressure peaks of the exhaust gas occurring in the exhaust tract 8 can lead to a brief opening of the exhaust valves, in particular at low cylinder pressures. This leads in particular at the end of the first work cycle (intake) or at the start of the second work cycle (compression) to a reloading effect in which exhaust gas from the exhaust system 8 reaches the cylinders of the internal combustion engine 1. The reloading effect leads to an increased cylinder charge and thus increased engine braking power. Weaker valve springs on the exhaust valves would open the exhaust valves again at lower pressure peaks and the braking performance could be further increased. However, it must be ensured that the exhaust valves follow the cam shape exactly when changing the gas and that the exhaust valves do not lift even at very high engine speeds. In engine braking operation, the power turbine 4 contributes to the braking power, since it is dragged along by the internal combustion engine 1.
In dem Motorsteuergerät 12 ist eine Kennlinie zur Steuerung der Konstantdrossel 2, des Radialleitgitters 11 und des Drehschieberventils 16 hinterlegt. Die Kennlinie ist zuvor in PrüfStandsversuchen abhängig von der Abgastemperatur der Brennkraftmaschine 1 und der Drehzahl des Abgasturboladers 3 ermittelt worden. Dabei wird der Übergangspunkt bei einer mittleren Drehzahl festgelegt, bei der die Konstantdrossel 2 mit dem Drehschieberventil 16 oder mit dem Radialleitgitter 11 und dem Drehschieberventil 16 zusammenwirkt. Der Übergangspunkt bei einer mittleren Drehzahl hangt von einer maximal zulässigen Abgastemperatur und/oder indizierten Arbeit im Motorbremsbetrieb aus der Hoch- undA characteristic curve for controlling the constant throttle 2, the radial guide vane 11 and the rotary slide valve 16 is stored in the engine control unit 12. The characteristic curve was previously determined in test bench tests depending on the exhaust gas temperature of the internal combustion engine 1 and the speed of the exhaust gas turbocharger 3. The transition point is determined at a medium speed at which the constant throttle 2 interacts with the rotary slide valve 16 or with the radial guide vane 11 and the rotary slide valve 16. The transition point at a medium speed depends on a maximum permissible exhaust gas temperature and / or indicated work in engine braking mode from the high and low
Niederdruckschleife ab. Bei Nutzfahrzeugmotoren mit etwa zwei Liter Hubraum pro Zylinder liegt der Übergangspunkt zwischen einer Drehzahl der Brennkraftmaschine 1 von n=1400/min und n=1600/min, vorzugsweise bei einer Drehzahl von n=1500/min.Low pressure loop. In commercial vehicle engines with a displacement of about two liters per cylinder, the transition point between a speed of the internal combustion engine 1 of n = 1400 / min and n = 1600 / min, preferably at a speed of n = 1500 / min.
Denkbar ist anstelle des Drehschieberventils 16 ein Schaltventil in die Abgasleitung 17 und ein Drosselventil in die Bypassleitung 15 einzubringen. Das Schaltventil und das Drosselventil sind über Steuerleitungen mit dem Motorsteuergerät 12 verbunden, das eine entsprechende Betätigungseinrichtungen an dem Schaltventil und dem Drosselventil ansteuern kann. Instead of the rotary slide valve 16, it is conceivable to introduce a switching valve into the exhaust line 17 and a throttle valve into the bypass line 15. The switching valve and the throttle valve are connected via control lines to the engine control unit 12, which can control corresponding actuation devices on the switching valve and the throttle valve.

Claims

Patentansprüche claims
1. Brennkraftmaschine (1) mit einer Motorbremseinrichtung (2) , insbesondere in Form einer Kompressionsbremse, mit mindestens einem Auslassventil pro Zylinder der Brennkraftmaschine (1) , mit einem Abgasturbolader (3) , dessen Abgasturbine (5) einem Abgastrakt (8) und dessen Verdichter (6) einem Ansaugtrakt (9) der Brennkraftmaschine (1) zugeordnet ist, mit einer vom Abgas der Brennkraftmaschine (1) angetriebenen und mit der Brennkraftmaschine (1) vorzugsweise über ein Getriebe (10) gekoppelten Nutzturbine (4) , die der Abgasturbine (5) des Abgasturboladers (3) nachgeschaltet ist, mit einer Bypassleitung (15) um die Nutzturbine (4) herum und einer Bypasseinrichtung (16) in der Bypassleitung (15) , wobei die Bypasseinrichtung (16) über eine Abgasleitung (17) mit der Nutzturbine (3) verbunden ist, dadurch gekennzeichnet, dass die Bypasseinrichtung (16) in Form eines kombinierten Schalt- und Drosselventils ausgeführt ist, so dass die Abgasleitung (17) vollständig und die Bypassleitung (15) vollständig oder teilweise schließbar ist.1. Internal combustion engine (1) with an engine brake device (2), in particular in the form of a compression brake, with at least one exhaust valve per cylinder of the internal combustion engine (1), with an exhaust gas turbocharger (3), the exhaust gas turbine (5), an exhaust tract (8) and its Compressor (6) is assigned to an intake tract (9) of the internal combustion engine (1), with a utility turbine (4) driven by the exhaust gas of the internal combustion engine (1) and coupled to the internal combustion engine (1), preferably via a transmission (10), that of the exhaust gas turbine (5) of the exhaust gas turbocharger (3) is connected downstream, with a bypass line (15) around the utility turbine (4) and a bypass device (16) in the bypass line (15), the bypass device (16) being connected via an exhaust line (17) of the utility turbine (3), characterized in that the bypass device (16) is designed in the form of a combined switching and throttle valve, so that the exhaust line (17) is complete and the bypass line (15) is fully or partially closable.
2. Brennkraftmaschine nach Anspruch 1, dadurch gekennzeichnet, dass die Bypasseinrichtung (16) so ausgeführt ist, dass bei vollständigen Schließen der Abgasleitung (17) und der Bypassleitung (15) durch die Bypasseinrichtung (16) , diese gasdicht geschlossen werden können.2. Internal combustion engine according to claim 1, characterized in that the bypass device (16) is designed such that when the exhaust line (17) and the bypass line (15) are completely closed by the bypass device (16), these can be closed gas-tight.
3. Brennkraftmaschine nach den Ansprüchen 1 bis 2, dadurch gekennzeichnet, dass die Bypasseinrichtung (16) in Form eines Drehschieberventils ausgeführt ist.3. Internal combustion engine according to claims 1 to 2, characterized in that the bypass device (16) is designed in the form of a rotary slide valve.
4. Brennkraftmaschine nach Anspruch 3 , dadurch gekennzeichnet, dass das Drehschieberventil (16) ein Gehäuse (21) mit einem darin eingebrachten rohrförmigen Kanal (22) aufweist, in dem ein frei drehbarer Rotor (23) gelagert ist, der mit einem kreisausschnittsförmigen Querschnitt ausgeführt ist.4. Internal combustion engine according to claim 3, characterized in that the rotary slide valve (16) has a housing (21) with a tubular channel (22) inserted therein, in which a freely rotatable rotor (23) is mounted, which is designed with a circular cross-section is.
5. Brennkraftmaschine nach Anspruch 4, dadurch gekennzeichnet, dass der kreisausschnittsförmige Querschnitt des Rotors (23) einen Kreisausschnittswinkel von 120° bis 140° aufweist.5. Internal combustion engine according to claim 4, characterized in that the circular section-shaped cross section of the rotor (23) has a circular section angle of 120 ° to 140 °.
6. Brennkraftmaschine nach den Ansprüchen 1 bis 5, dadurch gekennzeichnet, dass die Kompressionsbremse (2) im Motorbremsbetrieb öffnet und die Bypasseinrichtung (16) im Motorbremsbetrieb bei niedrigen bis mittleren Drehzahlen der Brennkraftmaschine (I) die Abgasleitung (17) und die Bypassleitung (15) schließt .6. Internal combustion engine according to claims 1 to 5, characterized in that the compression brake (2) opens in engine braking mode and the bypass device (16) in engine braking mode at low to medium engine speeds (I) the exhaust pipe (17) and the bypass line (15 ) closes.
7. Brennkraftmaschine nach den Ansprüchen 1 bis 6, dadurch gekennzeichnet, dass die Kompressionsbremse (2) im Motorbremsbetrieb öffnet und die Abgasturbine (5) über eine variable Turbinengeometrie (II) verfügt, die im Motorbremsbetrieb die Strömung des Abgases auf ein Turbinenrad so verändert, dass im Motorbremsbetrieb bei mittleren bis hohen Drehzahlen der Brennkraftmaschine (1) eine Erhöhung der Drehzahl der Abgasturbine (5) erfolgt, wobei die Bypasseinrichtung (16) die Abgasleitung (17) schließt und die Bypassleitung (15) vollständig öffnet.7. Internal combustion engine according to claims 1 to 6, characterized in that the compression brake (2) opens in engine braking mode and the exhaust gas turbine (5) has a variable turbine geometry (II) which changes the flow of the exhaust gas to a turbine wheel in engine braking mode, that in engine braking operation at medium to high speeds of the internal combustion engine (1) there is an increase in the speed of the exhaust gas turbine (5), the bypass device (16) closing the exhaust line (17) and completely opening the bypass line (15).
8. Brennkraftmaschine nach den Ansprüchen 1 bis 7, dadurch gekennzeichnet, dass die Kompressionsbremse (2) im Motorbremsbetrieb öffnet und die Abgasturbine (5) über eine variable Turbinengeometrie (11) verfügt, die im Motorbremsbetrieb die Strömung des Abgases auf ein Turbinenrad so verändert, dass im Motorbremsbetrieb bei hohen bis sehr hohen Drehzahlen der Brennkraftmaschine (1) eine Erhöhung der Drehzahl der Abgasturbine (5) erfolgt, wobei die Bypasseinrichtung (16) die Abgasleitung (17) schließt und die Bypassleitung (15) teilweise schließt.8. Internal combustion engine according to claims 1 to 7, characterized in that the compression brake (2) opens in the engine brake mode and the exhaust gas turbine (5) has a variable turbine geometry (11) which, in the engine brake mode, changes the flow of the exhaust gas onto a turbine wheel in such a way that in the engine brake mode at high to very high engine speeds (1) there is an increase in the speed of the exhaust gas turbine (5), the bypass device (16) closing the exhaust line (17) and partially closing the bypass line (15).
9. Brennkraftmaschine nach den Ansprüchen 1 bis 8, dadurch gekennzeichnet, dass im Motorbremsbetrieb die Auslassventile der Brennkraftmaschine (1) durch Druckspitzen des Abgases im Abgastrakt (8) kurzzeitig geöffnet werden können, wodurch Abgas aus dem Abgastrakt (8) in die Zylinder der Brennkraftmaschine (1) gelangt. 9. Internal combustion engine according to claims 1 to 8, characterized in that in engine braking operation, the exhaust valves of the internal combustion engine (1) can be opened briefly by pressure peaks of the exhaust gas in the exhaust tract (8), whereby exhaust gas from the exhaust tract (8) into the cylinders of the internal combustion engine (1) arrives.
EP04741405A 2003-08-29 2004-08-11 Internal combustion engine comprising an engine braking mechanism Withdrawn EP1658423A1 (en)

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DE2003139857 DE10339857A1 (en) 2003-08-29 2003-08-29 Combustion engine with motor brake system esp in the form of a constant throttle having a bypass unit in the form of a combined switch and throttle valve
PCT/EP2004/008978 WO2005028830A1 (en) 2003-08-29 2004-08-11 Internal combustion engine comprising an engine braking mechanism

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JP2007504383A (en) 2007-03-01
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US7347048B2 (en) 2008-03-25
US20060174620A1 (en) 2006-08-10

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