EP0193142B1 - Engine-braking system for an internal-combustion engine - Google Patents

Engine-braking system for an internal-combustion engine Download PDF

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Publication number
EP0193142B1
EP0193142B1 EP86102326A EP86102326A EP0193142B1 EP 0193142 B1 EP0193142 B1 EP 0193142B1 EP 86102326 A EP86102326 A EP 86102326A EP 86102326 A EP86102326 A EP 86102326A EP 0193142 B1 EP0193142 B1 EP 0193142B1
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EP
European Patent Office
Prior art keywords
valve
engine
piston
braking system
spring
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.)
Expired
Application number
EP86102326A
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German (de)
French (fr)
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EP0193142A1 (en
Inventor
Achim Zur Nieden
Toni Kleinschmidt
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Kloeckner Humboldt Deutz AG
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Kloeckner Humboldt Deutz AG
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Publication of EP0193142A1 publication Critical patent/EP0193142A1/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
    • F01L13/06—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
    • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
    • F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic
    • F01L9/18—Means for increasing the initial opening force on the valve
    • 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
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L2003/25—Valve configurations in relation to engine
    • F01L2003/258—Valve configurations in relation to engine opening away from cylinder
    • 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
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the invention relates to an engine brake device for an internal combustion engine according to the preamble of claim 1 or 3.
  • CH-A-310 325 an engine brake device for an internal combustion engine is described, in which the combustion chamber is connected to the exhaust duct via a further closable gas duct, which increases the engine braking power by the blow-off and throttling action.
  • a valve is arranged in the gas duct, which can be actuated simultaneously via a linkage with a throttle valve in the exhaust duct. If the throttle valve is closed, the linkage simultaneously opens the valve in the gas duct and vice versa.
  • the gas channel can also be formed by an annular gap between the valve plate and valve seat.
  • the disadvantage is the complicated and complex control of the engine brake device by means of a linkage, which takes up special fastening points and space in the internal combustion engine and, despite regular lubrication, tends to show signs of failure during extended operation.
  • US-A-3 520 287 describes an engine brake device in which an annular gap is formed between the valve disk and the valve seat of the exhaust valve for the duration of the braking operation.
  • This annular gap is controlled by a hydraulic adjusting device integrated in the oil circuit of the internal combustion engine, oil being conveyed into the adjusting device via a pump in braking operation, whereby the adjusting device opens the annular gap.
  • a disadvantage is the complex control of this engine brake device.
  • the object of the invention is to provide an engine braking device which automatically adjusts itself to normal or braking operation.
  • this is achieved in that the actuating device is acted upon by the gas pressure in the exhaust gas duct in such a way that the further gas duct is open when the throttle valve is closed.
  • valve has a piston which is spring-loaded in the closed position of the valve in the actuating device, the effective piston area of which, in the opening direction of the valve, is acted upon by the gas pressure prevailing in the exhaust duct before the throttle valve in the opening direction of the valve.
  • the force of the spring on the piston surface must be dimensioned such that the valve assigned to the gas channel always remains closed when the throttle valve is open, i.e. that even the maximum ignition pressure in the combustion chamber cannot open the valve.
  • the piston surface facing away from the spring must be chosen so large that the gas pressure in the exhaust duct can move the piston when the throttle valve is closed and thus open the valve.
  • the valve is expediently located close to the combustion chamber, so in normal operation, i.e. When the throttle valve is open, no dead volume affects the function of the engine.
  • An alternative embodiment relates to an engine brake device for an internal combustion engine, in particular for a self-priming or supercharged diesel engine with at least one combustion chamber, which is connected via an outlet valve to an exhaust gas duct, with a hydraulic actuating device integrated into the oil circuit of the internal combustion engine during braking operation of the internal combustion engine between the valve plate and An annular gap is formed in the valve seat of the exhaust valve.
  • a throttle valve which is closed during braking operation is arranged in the exhaust duct and the setting of the annular gap is carried out automatically by the gas pressure in the exhaust duct.
  • the annular gap between the valve plate and the valve seat of the exhaust valve which has a throttle characteristic in relation to the cross section of the exhaust valve, can be defined in a defined manner.
  • a pressure chamber which is closable on the one hand by a counterpressure valve and on the other hand by a control piston is arranged in an oil line to the rocker arm space or valve space, the one limiting side of which forms a piston which is movably sealed in a cylinder in its axial direction.
  • the back pressure valve advantageously consists of a spring-loaded ball arranged in the pressure chamber, which is pressed in the closed position of the back pressure valve by the oil pressure in the pressure chamber onto the inlet of the oil line in the pressure chamber and closes the pressure chamber.
  • the control piston is advantageously connected at its end facing away from the pressure chamber to a membrane which is acted upon by the gas pressure in the exhaust duct against a spring force, such that the gas pressure in combustion mode of the internal combustion engine shifts the membrane with the control piston against the spring force and the control piston unilaterally the pressure chamber closes.
  • the piston expediently sets the rest position of the outlet valve, which position forms an end position, via an adjusting device, and the adjusting device consists of an auxiliary rocker arm, one end of which cooperates with the piston and the other end of which cooperates with the valve stem.
  • the auxiliary rocker arm can advantageously be adjusted in its axial position.
  • FIG. 1 shows an engine brake device according to the invention as a section through a cylinder head 5 with an adjacent cylinder tube 11.
  • the combustion chamber 1 is delimited by the cylinder tube 11, by the cylinder head 5 and by a piston (not shown).
  • the cylinder tube 11 is opposite the cylinder Head 5 sealed by a sealing ring arranged in a groove 29 in the cylinder head 5.
  • the exhaust gas duct 3 In the cylinder head 5 there is the exhaust gas duct 3, the connection to the combustion chamber 1 of which is controlled by an exhaust valve 2 moved by a rocker arm 13.
  • the valve plate 6 is conical and sits in a correspondingly designed valve seat 7.
  • the valve seat 15 is guided in a valve guide 14 which is fastened in the cylinder head 5.
  • valve stem 15 At the upper end of the valve stem 15, a spring plate 28 is attached, via which a valve spring 16 loads the valve in the closed position. Via a rocker arm 13 driven by a camshaft, the valve stem 15 is moved axially against the force of the valve spring 16 in time with the internal combustion engine and the outlet valve 2 is opened, which is closed again by the valve spring 16 when the rocker arm I 1 3 returns.
  • the combustion chamber 1 is connected to the exhaust gas duct 3 via a second gas duct 4 provided in the cylinder head 5 and controlled by a valve 8.
  • valve stem 17 of the valve 8 protrudes through the gas channel 3 and lies parallel to the valve stem of the exhaust valve 2. Its lower end is conical as a valve plate 18 and sits in the associated valve seat 12. The through hole of the valve seat leads into the gas channel 4, which in the Combustion chamber 1 opens.
  • the blow-off cross section of the gas channel 4 has a throttle characteristic in comparison to the effective outlet cross section of the exhaust valve.
  • the blow-off cross-section is preferably less than 1: 3 in diameter ratio or less than 1:10 in area ratio compared to outlet valve.
  • valve stem 17 of the valve 8 protrudes into an adjusting device 19.
  • the valve stem 17 is guided in the lower part 20 of the actuating device and connected to the piston 10, which has three grooves or piston rings 24 on its running surface and divides the interior of the upper part 22 into two subspaces.
  • the side of the piston 10 facing away from the gas channel 4 is loaded by a spring 26.
  • the spring chamber communicates with the atmosphere through a bore 27; the side of the piston 10 opposite the spring 26 is connected to the exhaust duct 3 via a bore 21.
  • This has the same order of magnitude as the braking power with a throttle valve without a gas channel in the two work cycles «pushing out and priming» and is added to this.
  • the gas channel 4 is replaced by an annular gap 4 ′ formed in the closed position of the exhaust valve 2 between the valve plate 6 and the valve seat 7 of the exhaust valve (shown in broken lines).
  • Fig. 2 shows this advantageous embodiment, which is explained below.
  • An exhaust valve 2 arranged in the cylinder head 5 projects through its exhaust shaft 15 through an exhaust duct 3 and sits with its valve plate 6 in a valve seat 7.
  • the rocker arm 13 is actuated by a camshaft 31, the camshaft 31 being connected to the rocker arm 13 via a plunger 43.
  • a rod 44 is arranged in the cylinder head 5, which is screwed into the cylinder head 5 at one end.
  • the rod 44 serves as a fastening for an auxiliary rocker arm 42 which is placed on the rod 44.
  • the rod 44 has two nuts 45 which, together with an abutment 4a, serve as a stop for the auxiliary rocker arm 42.
  • the auxiliary rocker arm 42 is pressed against the nuts 45 by a spring 46 which coaxially surrounds the rod 44.
  • the auxiliary rocker arm 42 is in the manner of a balance beam and is also elastically supported by the spring 46.
  • An arm 48 of the auxiliary rocker arm 42 is U-shaped and lies on the ring 30a, which is on the end face of the valve shaft 15 rests on.
  • a spherical pin 47 of the rocker arm 13 is arranged within the U-shaped arm 48 of the auxiliary rocker arm 42 and acts on the cylindrical extension 30b of the ring 30a.
  • the arm of the auxiliary rocker arm 42 opposite the U-shaped arm 48 rests on a piston 37 which is movably sealingly guided in its axial direction in a cylindrical bore in the cylinder head 5.
  • the movement of the piston 37 is limited by a stop 49.
  • the bottom of the piston 37 facing the exhaust gas duct 3 forms one side of a pressure chamber 36 in the cylinder head 5, the pressure chamber 36 having an inlet 39 and an outlet 40.
  • the inlet 39 is formed by an oil line 34 of the internal combustion engine, which is integrated in the oil circuit of the internal combustion engine.
  • a throttle 32 is arranged in the oil line 34, which throttles the flow of the oil through the oil line 34.
  • the outlet 40 of the pressure chamber 36 merges into a bore 50 arranged parallel to the valve stem 15, which is connected on the one hand to the valve chamber or rocker arm chamber and on the other hand merges into a spring chamber 51.
  • a membrane 41 is arranged in the spring chamber 51 and divides the spring chamber 51 from an adjacent gas chamber 52. Both spaces are separated from one another by the membrane 41 in a gastight manner.
  • a cylindrical control piston 35 is attached to the diaphragm 41, which extends through the spring chamber 51 and projects into the bore 50. The control piston 35 is coupled to the movement of the membrane 41 and seals the outlet 40 of the pressure chamber 36 when the membrane 41 extends in the direction of the spring chamber 51.
  • a compression spring 53 is arranged coaxially around the control piston 35 and acts upon the membrane 41 in the direction of the gas chamber 52.
  • the gas space 52 is connected to the exhaust duct 3 through a bore 54.
  • a counter pressure valve Arranged in the pressure chamber 36 is a counter pressure valve which consists of a spring-loaded ball 38 which, in the closed position of the counter pressure valve, is pressed from the oil pressure in the pressure chamber 36 onto the inlet 39 of the oil line 34 into the pressure chamber 36 and closes it. So that the ball 38 only performs a defined axial change in position, it is held by a conically shaped spring 55.
  • the spring 55 is supported on the one hand on a U-shaped bracket 56 in the pressure chamber 36 and on the other hand on the ball 38.
  • the throttle valve 9 in the exhaust gas duct 3 is open, so that no high gas pressure builds up in the exhaust gas duct 3.
  • the gas pressure in the exhaust duct 3, which acts on the diaphragm 41 via the bore 54, is not sufficient to bulge it against the force of the compression spring 53 in the direction of the spring chamber 51.
  • the control piston 35 does not close the outlet 40 of the pressure chamber 36, so that the oil flowing through the oil line 34 passes unhindered through the pressure chamber 36 into the valve or rocker arm chamber.
  • the piston 37 can yield to the oil pressure and change its position in the direction of the stop 49, and the auxiliary rocker arm 42, so that, despite the open outlet 40, the piston 37 the U-shaped arm 48 of the auxiliary rocker arm 42 is deflected in the direction of the valve seat 7. If the outlet valve 2 returns to the closed position, the auxiliary rocker arm 42 immediately returns to its original position, since the piston 37 presses the oil in the pressure chamber 36 through the outlet 40 into the valve chamber or rocker arm chamber.
  • this process is of subordinate importance for the mode of operation of the engine brake device according to the invention and can also be avoided by suitably coordinating the size of the outlet 40 in connection with the throttle 32. It is important according to the invention that the movement of the outlet valve 2 is unaffected in normal operation.
  • the throttle valve 9 in the exhaust duct 3 is closed, and the gas pressure in the exhaust duct 3 is sufficient to bulge the diaphragm 41 with the control piston 37 attached thereto in the direction of the spring chamber 51 against the force of the compression spring 53.
  • the control piston 37 then closes the outlet 40 of the pressure chamber 36. If the outlet valve 2 is just in the open position, oil flows from the oil line 34 into the pressure chamber 36 and pushes the piston 37 up to a stop 49. If the outlet valve 2 returns to the closed position , then the ring 30a returning to the rest position on the valve stem 15 lifts the U-shaped arm 48 of the auxiliary rocker arm 42 and thereby presses the opposite arm onto the piston 37.
  • a pressure builds up in the pressure chamber 36, which pressures the inlet 39 of the back pressure valve closes when the pressure in the pressure chamber 36 is greater than in the oil line 34.
  • the auxiliary rocker arm 42 can no longer return to its rest position, so that the outlet valve 2 also remains in a certain deflected end position.
  • the end position of the exhaust valve 2 is selected such that the annular gap 4 ′ between the valve plate 6 and the valve seat 7 of the exhaust valve 2 has a throttle characteristic in relation to the cross section of the exhaust valve 2.
  • the setting of the annular gap 4 ' is accordingly carried out automatically by hydraulic means, controlled by the gas pressure in the exhaust gas duct. Furthermore, due to the incompressibility of the oil, the annular gap 4 ′ which determines the throttle cross section can be precisely defined.
  • the nuts 45 on the rod 44 allow the axial position of the auxiliary rocker arm 42 and thus the throttle cross section of the ring channel 4 'to be determined or corrected even after the internal combustion engine has been installed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Valve Device For Special Equipments (AREA)
  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)

Description

Die Erfindung betrifft eine Motorbremsvorrichtung für eine Brennkraftmaschine gemäss Oberbegriff des Anspruchs 1 oder 3.The invention relates to an engine brake device for an internal combustion engine according to the preamble of claim 1 or 3.

In der CH-A-310 325 ist eine Motorbremsvorrichtung für eine Brennkraftmaschine beschrieben, bei welcher der Brennraum mit dem Abgaskanal über einen weiteren verschliessbaren Gaskanal verbunden ist, welcher durch Abblase- und Drosselwirkung die Motorbremsleistung erhöht. Im Gaskanal ist ein Ventil angeordnet, welches über ein Gestänge simultan mit einer Drosselklappe im Abgaskanal zu betätigen ist. Wird die Drosselklappe geschlossen, so öffnet das Gestänge gleichzeitig das Ventil im Gaskanal und umgekehrt. In anderer Ausführungsform kann nach der CH-PS 310 325 der Gaskanal auch durch einen Ringspalt zwischen Ventilteller und Ventilsitz gebildet sein.In CH-A-310 325 an engine brake device for an internal combustion engine is described, in which the combustion chamber is connected to the exhaust duct via a further closable gas duct, which increases the engine braking power by the blow-off and throttling action. A valve is arranged in the gas duct, which can be actuated simultaneously via a linkage with a throttle valve in the exhaust duct. If the throttle valve is closed, the linkage simultaneously opens the valve in the gas duct and vice versa. In another embodiment, according to CH-PS 310 325, the gas channel can also be formed by an annular gap between the valve plate and valve seat.

Nachteilig ist die komplizierte und aufwendige Steuerung der Motorbremsvorrichtung durch ein Gestänge, welches in der Brennkraftmaschine besondere Befestigungspunkte und Platz beansprucht, und trotz regelmässiger Schmierung bei längerem Betrieb zu Ausfallerscheinungen neigt.The disadvantage is the complicated and complex control of the engine brake device by means of a linkage, which takes up special fastening points and space in the internal combustion engine and, despite regular lubrication, tends to show signs of failure during extended operation.

In der US-A-3 520 287 ist eine Motorbremsvorrichtung beschrieben, bei der für die Dauer des Bremsbetriebes zwischen Ventilteller und Ventilsitz des Auslassventils ein Ringspalt gebildet ist. Dieser Ringspalt ist durch eine in den Ölkreislauf der Brennkraftmaschine integrierte hydraulische Stellvorrichtung gesteuert, wobei im Bremsbetrieb Öl über eine Pumpe in die Stellvorrichtung gefördert wird, wodurch die Stellvorrichtung den Ringspalt öffnet. Nachteilig ist die aufwendige Steuerung dieser Motorbremsvorrichtung.US-A-3 520 287 describes an engine brake device in which an annular gap is formed between the valve disk and the valve seat of the exhaust valve for the duration of the braking operation. This annular gap is controlled by a hydraulic adjusting device integrated in the oil circuit of the internal combustion engine, oil being conveyed into the adjusting device via a pump in braking operation, whereby the adjusting device opens the annular gap. A disadvantage is the complex control of this engine brake device.

Aufgabe der Erfindung ist es, eine Motorbremsvorrichtung zu schaffen, die sich selbsttätig auf Normal-oder Bremsbetrieb einstellt.The object of the invention is to provide an engine braking device which automatically adjusts itself to normal or braking operation.

Erfindungsgemäss wird dies dadurch gelöst, dass die Stellvorrichtung vom Gasdruck im Abgaskanal derart beaufschlagt ist, dass bei geschlossener Drosselklappe der weitere Gaskanal geöffnet ist.According to the invention, this is achieved in that the actuating device is acted upon by the gas pressure in the exhaust gas duct in such a way that the further gas duct is open when the throttle valve is closed.

In vorteilhafter Ausführung wird dies dadurch erreicht, dass das Ventil einen in Schliessstellung des Ventils federbelasteten Kolben in der Stellvorrichtung aufweist, wobei dessen eine wirksame Kolbenfläche im Öffnungssinn des Ventils gegen die Kraft der Feder vom im Abgaskanal vor der Drosselklappe herrschenden Gasdruck beaufschlagt ist.In an advantageous embodiment, this is achieved in that the valve has a piston which is spring-loaded in the closed position of the valve in the actuating device, the effective piston area of which, in the opening direction of the valve, is acted upon by the gas pressure prevailing in the exhaust duct before the throttle valve in the opening direction of the valve.

Die Kraft der Feder auf die Kolbenfläche muss so dimensioniert sein, dass das dem Gaskanal zugeordnete Ventil bei geöffneter Drosselklappe immer geschlossen bleibt, d.h. dass auch der maximale Zünddruck im Brennraum das Ventil nicht öffnen kann. Demgegenüber muss die der Feder abgewandte Kolbenfläche so gross gewählt werden, dass der Gasdruck im Abgaskanal bei geschlossener Drosselklappe den Kolben bewegen und damit das Ventil öffnen kann.The force of the spring on the piston surface must be dimensioned such that the valve assigned to the gas channel always remains closed when the throttle valve is open, i.e. that even the maximum ignition pressure in the combustion chamber cannot open the valve. In contrast, the piston surface facing away from the spring must be chosen so large that the gas pressure in the exhaust duct can move the piston when the throttle valve is closed and thus open the valve.

Zweckmässigerweise liegt das Ventil dicht am Brennraum, damit im Normalbetrieb, d.h. bei geöffneter Drosselklappe, kein Totvolumen die Funktion des Motors beeinflusst.The valve is expediently located close to the combustion chamber, so in normal operation, i.e. When the throttle valve is open, no dead volume affects the function of the engine.

Eine alternative Ausführungsform betrifft eine Motorbremsvorrichtung für eine Brennkraftmaschine, insbesondere für einen selbstansaugenden oder aufgeladenen Dieselmotor mit mindestens einem Brennraum, der über ein Auslassventil mit einem Abgaskanal verbunden ist, wobei durch eine in den Ölkreislauf der Brennkraftmaschine integrierte hydraulische Stellvorrichtung im Bremsbetrieb der Brennkraftmaschine zwischen Ventilteller und Ventilsitz des Auslassventils ein Ringspalt gebildet ist. Erfindungsgemäss ist im Abgaskanal eine im Bremsbetrieb geschlossene Drosselklappe angeordnet und die Einstellung des Ringspaltes erfolgt selbsttätig durch den Gasdruck im Abgaskanal gesteuert.An alternative embodiment relates to an engine brake device for an internal combustion engine, in particular for a self-priming or supercharged diesel engine with at least one combustion chamber, which is connected via an outlet valve to an exhaust gas duct, with a hydraulic actuating device integrated into the oil circuit of the internal combustion engine during braking operation of the internal combustion engine between the valve plate and An annular gap is formed in the valve seat of the exhaust valve. According to the invention, a throttle valve which is closed during braking operation is arranged in the exhaust duct and the setting of the annular gap is carried out automatically by the gas pressure in the exhaust duct.

Mit dieser hydraulischen Einstellung ist der Ringspalt zwischen Ventilteller und Ventilsitz des Auslassventils, der im Verhältnis zum Querschnitt des Auslassventils eine Drosselcharakteristik aufweist, definiert einstellbar.With this hydraulic setting, the annular gap between the valve plate and the valve seat of the exhaust valve, which has a throttle characteristic in relation to the cross section of the exhaust valve, can be defined in a defined manner.

Zweckmässigerweise ist in einer Ölleitung zum Kipphebelraum bzw. Ventilraum ein einerseits durch ein Gegendruckventil und andererseits durch einen Steuerkolben schliessbarer Druckraum angeordnet, dessen eine begrenzende Seite ein Kolben bildet, der in seiner Axialrichtung bewegbar dichtend in einem Zylinder geführt ist. Dabei besteht das Gegendruckventil vorteilhafterweise aus einer im Druckraum angeordneten federbelasteten Kugel, die in Schliessstellung des Gegendruckventils vom Öldruck im Druckraum auf den Einlass der Ölleitung in den Druckraum gepresst ist und den Druckraum verschliesst.A pressure chamber which is closable on the one hand by a counterpressure valve and on the other hand by a control piston is arranged in an oil line to the rocker arm space or valve space, the one limiting side of which forms a piston which is movably sealed in a cylinder in its axial direction. The back pressure valve advantageously consists of a spring-loaded ball arranged in the pressure chamber, which is pressed in the closed position of the back pressure valve by the oil pressure in the pressure chamber onto the inlet of the oil line in the pressure chamber and closes the pressure chamber.

Der Steuerkolben ist vorteilhafterweise an seinem dem Druckraum abgewandten Ende mit einer Membran verbunden, die vom Gasdruck im Abgaskanal entgegen einer Federkraft beaufschlagt ist, derart, dass der Gasdruck im Brennbetrieb der Brennkraftmaschine die Membran mit dem Steuerkolben entgegen der Federkraft verschiebt und der Steuerkolben den Druckraum einseitig schliesst.The control piston is advantageously connected at its end facing away from the pressure chamber to a membrane which is acted upon by the gas pressure in the exhaust duct against a spring force, such that the gas pressure in combustion mode of the internal combustion engine shifts the membrane with the control piston against the spring force and the control piston unilaterally the pressure chamber closes.

Sinnvollerweise legt der Kolben über eine Stellvorrichtung die eine Endlage bildende Ruhestellung des Auslassventils fest, und die Stellvorrichtung besteht aus einem Hilfskipphebel, dessen eines Ende mit dem Kolben und dessen anderes Ende mit dem Ventilschaft zusammenwirkt.The piston expediently sets the rest position of the outlet valve, which position forms an end position, via an adjusting device, and the adjusting device consists of an auxiliary rocker arm, one end of which cooperates with the piston and the other end of which cooperates with the valve stem.

Damit der Ringspaltzwischen Ventilteller und Ventilsitz des Auslassventils definiert einstellbar ist, ist der Hilfskipphebel vorteilhafterweise in seiner axialen Lage einstellbar.In order for the annular gap between the valve plate and the valve seat of the exhaust valve to be adjustable, the auxiliary rocker arm can advantageously be adjusted in its axial position.

Weitere Merkmale der Erfindung ergeben sich aus der Beschreibung und den Zeichnungen, die zwei Ausführungsformen der Erfindung zeigen und nachfolgend näher beschrieben sind. Es zeigt:

  • Fig. 1 eine erfindungsgemässe Motorbremsvorrichtung als Schnitt durch einen Zylinderkopf mit angrenzendem Zylinderrohr,
  • Fig. 2 einen Schnitt durch einen Zylinderkopf mit einer erfindungsgemässen Motorbremsvorrichtung, wobei der Gaskanal durch einen Ringspalt zwischen einem Ventilteller und Ventilsitz ersetzt ist.
Further features of the invention result from the description and the drawings, which show two embodiments of the invention and are described in more detail below. It shows:
  • 1 shows an engine brake device according to the invention as a section through a cylinder head with an adjacent cylinder tube,
  • Fig. 2 shows a section through a cylinder head with an engine brake device according to the invention, wherein the gas channel is replaced by an annular gap between a valve plate and valve seat.

Fig. 1 zeigt eine erfindungsgemässe Motorbremsvorrichtung als Schnitt durch einen Zylinderkopf 5 mit angrenzendem Zylinderrohr 11. Der Brennraum 1 wird vom Zylinderrohr 11, vom Zylinderkopf 5 und von einem nicht eingezeichneten Kolben begrenzt. Das Zylinderrohr 11 ist gegenüber dem Zylinderkopf 5 durch einen in einer Nut 29 im Zylinderkopf 5 angeordneten Dichtungsring abgedichtet. Im Zylinderkopf 5 befindet sich der Abgaskanal 3, dessen Verbindung zum Brennraum 1 durch ein von einem Kipphebel 13 bewegtes Auslassventil 2 gesteuert wird. Der Ventilteller 6 ist kegelförmig ausgebildet und sitzt in einem entsprechend ausgebildeten Ventilsitz 7. Der Ventilsitz 15 ist in einer Ventilführung 14 geführt, die im Zylinderkopf 5 befestigt ist. Am oberen Ende des Ventilschafts 15 ist ein Federteller 28 angebracht, über den eine Ventilfeder 16 das Ventil in Schliessstellung belastet. Über einen von einer Nockenwelle angetriebenen Kipphebel 13 wird der Ventilschaft 15 gegen die Kraft der Ventilfeder 16 im Takt der Brennkraftmaschine axial bewegt und das Auslassventil 2 geöffnet, das durch die Ventilfeder 16 bei zurückführendem KipphebeI 1 3 wieder geschlossen wird.1 shows an engine brake device according to the invention as a section through a cylinder head 5 with an adjacent cylinder tube 11. The combustion chamber 1 is delimited by the cylinder tube 11, by the cylinder head 5 and by a piston (not shown). The cylinder tube 11 is opposite the cylinder Head 5 sealed by a sealing ring arranged in a groove 29 in the cylinder head 5. In the cylinder head 5 there is the exhaust gas duct 3, the connection to the combustion chamber 1 of which is controlled by an exhaust valve 2 moved by a rocker arm 13. The valve plate 6 is conical and sits in a correspondingly designed valve seat 7. The valve seat 15 is guided in a valve guide 14 which is fastened in the cylinder head 5. At the upper end of the valve stem 15, a spring plate 28 is attached, via which a valve spring 16 loads the valve in the closed position. Via a rocker arm 13 driven by a camshaft, the valve stem 15 is moved axially against the force of the valve spring 16 in time with the internal combustion engine and the outlet valve 2 is opened, which is closed again by the valve spring 16 when the rocker arm I 1 3 returns.

Der Brennraum 1 ist über einen im Zylinderkopf 5 vorgesehenen, von einem Ventil 8 beherrschten zweiten Gaskanal 4 mit dem Abgaskanal 3 verbunden.The combustion chamber 1 is connected to the exhaust gas duct 3 via a second gas duct 4 provided in the cylinder head 5 and controlled by a valve 8.

Der Ventilschaft 17 des Ventils 8 ragt durch den Gaskanal 3 und liegt parallel neben dem Ventilschaft des Auslassventils 2. Sein unteres Ende ist als Ventilteller 18 konisch gebaut und sitzt im dazugehörigen Ventilsitz 12. Die Durchlassbohrung des Ventilsitzes führt in den Gaskanal 4, der in den Brennraum 1 mündet.The valve stem 17 of the valve 8 protrudes through the gas channel 3 and lies parallel to the valve stem of the exhaust valve 2. Its lower end is conical as a valve plate 18 and sits in the associated valve seat 12. The through hole of the valve seat leads into the gas channel 4, which in the Combustion chamber 1 opens.

Der Abblasequerschnitt des Gaskanals 4 hat eine Drosselcharakteristik im Vergleich zum wirksamen Auslassquerschnitt des Auslassventils. Vorzugsweise beträgt der Abblasequerschnitt im Vergleich zum Auslassventil im Durchmesserverhältnis weniger als 1 : 3 bzw. im Flächenverhältnis weniger als 1 : 10.The blow-off cross section of the gas channel 4 has a throttle characteristic in comparison to the effective outlet cross section of the exhaust valve. The blow-off cross-section is preferably less than 1: 3 in diameter ratio or less than 1:10 in area ratio compared to outlet valve.

Der Ventilschaft 17 des Ventils 8 ragt in eine Stellvorrichtung 19. Diese bildet mit dem Ventilstössel 17 eine Baueinheit und kann als Ganzes dichtend in den Zylinderkopf 5 eingesetzt werden. Dazu sind im Zylinderkopf entsprechende Gewindebohrungen angebracht.The valve stem 17 of the valve 8 protrudes into an adjusting device 19. This forms a structural unit with the valve tappet 17 and can be inserted as a whole into the cylinder head 5 in a sealing manner. Appropriate threaded holes are made in the cylinder head for this purpose.

Ein Vorteil der beschriebenen Anordnung ist, dass diese Bohrungen als Montagedurchführung für den Einbau oder die Bearbeitung des Ventilsitzes 17 dienen können, solange die Baueinheit der Stellvorrichtung noch nicht eingesetzt ist.An advantage of the arrangement described is that these bores can serve as an assembly lead-through for the installation or machining of the valve seat 17 as long as the structural unit of the actuating device has not yet been used.

Der Ventilschaft 17 ist im Unterteil 20 der Stellvorrichtung geführt und mit dem Kolben 10 verbunden, der an seiner Lauffläche drei Nuten oder Kolbenringe 24 hat und den Innenraum des Oberteils 22 in zwei Teilräume aufteilt. Die dem Gaskanal 4 abgewandte Seite des Kolbens 10 ist durch eine Feder 26 belastet. Der Federraum steht durch eine Bohrung 27 mit der Atmosphäre in Verbindung; die der Feder 26 entgegengesetzte Seite des Kolbens 10 steht über eine Bohrung 21 mit dem Abgaskanal 3 in Verbindung.The valve stem 17 is guided in the lower part 20 of the actuating device and connected to the piston 10, which has three grooves or piston rings 24 on its running surface and divides the interior of the upper part 22 into two subspaces. The side of the piston 10 facing away from the gas channel 4 is loaded by a spring 26. The spring chamber communicates with the atmosphere through a bore 27; the side of the piston 10 opposite the spring 26 is connected to the exhaust duct 3 via a bore 21.

In der Strömungsrichtung des Abgaskanals 3 hinter der Mündung des Gaskanals 4 und der Bohrung 21 befindet sich eine fernbetätigbare Drosselklappe 9, üblicherweise für mehrere Zylinder zentral im Abgas-Sammelrohr (nicht dargestellt) angeordnet.In the direction of flow of the exhaust gas duct 3, behind the mouth of the gas duct 4 and the bore 21, there is a remotely operable throttle valve 9, usually arranged centrally for several cylinders in the exhaust gas manifold (not shown).

Ist die Drosselklappe 9 geschlossen, baut sich im Abgaskanal 3 nach wenigen Arbeitstakten des Kolbens ein Überdruck auf. Durch die Bohrung liegt dieser Überdruck auch an der dem Gaskanal 4 zugewandten Seite des Kolbens 10. Die wirksame Kolbenfläche ist so gewählt, dass der Überdruck den Kolben 10 gegen die Kraft der Feder 26 verschiebt und damit den Ventilschaft 17 anhebt, wodurch der Gaskanal 4 geöffnet wird.If the throttle valve 9 is closed, an excess pressure builds up in the exhaust duct 3 after a few working cycles of the piston. Through the bore, this overpressure is also on the side of the piston 10 facing the gas channel 4. The effective piston area is selected such that the overpressure displaces the piston 10 against the force of the spring 26 and thus lifts the valve stem 17, thereby opening the gas channel 4 becomes.

Zu Beginn des Kompressionstaktes ist der Druck im Brennraum 1 niedriger als im Abgaskanal 3. Dadurch strömt Gas durch den geöffneten Gaskanal 4 in den Brennraum und vergrössert dort die Füllung. Beim anschliessenden Komprimieren muss der Kolben zusätzliche Arbeit leisten und wird dadurch gebremst. Im weiteren Verlauf des Kompressionstaktes, wenn der Druck im Brennraum 1 höher ist als derjenige in der Abgasleitung 3, strömt Gas aus dem Brennraum 1 durch den Gaskanal 4 ab. Dadurch ist der Kompressionsenddruck niedriger als im Normalbetrieb mit geschlossenem Gaskanal 4; jedoch sind durch das Ausströmen irreversible Arbeitsverluste entstanden. Im anschliessenden Expansionstakt kann diese abgedrosselte Gasmenge nicht mehr auf den Kolben zurückwirken. In diesen beiden Arbeitstakten «Komprimieren und Expandieren» des Gases in der Brennkraftmaschine muss also vom Motor eine erhebliche Bremsarbeit geleistet werden.At the beginning of the compression cycle, the pressure in the combustion chamber 1 is lower than in the exhaust gas duct 3. As a result, gas flows through the open gas duct 4 into the combustion chamber and increases the charge there. During the subsequent compression, the piston has to do additional work and is therefore slowed down. In the further course of the compression stroke, when the pressure in the combustion chamber 1 is higher than that in the exhaust pipe 3, gas flows out of the combustion chamber 1 through the gas channel 4. As a result, the compression end pressure is lower than in normal operation with closed gas channel 4; however, irreversible labor losses have arisen from the leak. In the subsequent expansion stroke, this throttled amount of gas can no longer affect the piston. In these two work cycles of "compressing and expanding" the gas in the internal combustion engine, the engine must therefore perform a considerable amount of braking.

Diese hat die gleiche Grössenordnung wie die Bremsleistung mit Drosselklappe ohne Gaskanal in den beiden Arbeitstakten «Ausschieben und Ansaugen» und addiert sich zu dieser.This has the same order of magnitude as the braking power with a throttle valve without a gas channel in the two work cycles «pushing out and priming» and is added to this.

In einer weiteren Ausführungsform ist der Gaskanal 4 durch einen in geschlossener Stellung des Auslassventils 2 gebildeten Ringspalt 4' zwischen Ventilteller 6 und Ventilsitz 7 des Auslassventils ersetzt (strichliert eingezeichnet). Ein Vorteil dieser Bauform ist, dass kein zusätzlicher Gaskanal im Zylinderkopf erforderlich ist.In a further embodiment, the gas channel 4 is replaced by an annular gap 4 ′ formed in the closed position of the exhaust valve 2 between the valve plate 6 and the valve seat 7 of the exhaust valve (shown in broken lines). An advantage of this design is that no additional gas channel is required in the cylinder head.

Fig. 2 zeigt diese vorteilhafte Ausführungsform, die im folgenden erläutert wird.Fig. 2 shows this advantageous embodiment, which is explained below.

Ein im Zylinderkopf 5 angeordnetes Auslassventil 2 (vgl. Fig. 1) durchragt mit seinem Ventilschaft 15 einen Abgaskanal 3 und sitzt mit seinem Ventilteller 6 in einem Ventilsitz 7. Auf der der Ventilfeder 16 abgewandten Seite des Federtellers 28 ist ein Ring 30a mit einer zylindrischen Erweiterung 30b auf den Ventilschaft 15 aufgesetzt, der von einem nur schematisch gezeigten Kipphebel 13 kraftbeaufschlagt wird und den Ventilschaft 15 und damit den Ventilteller 6 in Öffnungsstellung des Auslassventils 2 verschiebt. Der Kipphebel 13 wird von einer,Nockenwelle 31 betätigt, wobei die Nockenwelle 31 mit dem Kipphebel 13 über einen Stössel 43 verbunden ist.An exhaust valve 2 arranged in the cylinder head 5 (cf. FIG. 1) projects through its exhaust shaft 15 through an exhaust duct 3 and sits with its valve plate 6 in a valve seat 7. On the side of the spring plate 28 facing away from the valve spring 16 there is a ring 30a with a cylindrical one Extension 30b is placed on the valve stem 15, which is acted upon by a rocker arm 13, which is only shown schematically, and which displaces the valve stem 15 and thus the valve disk 6 in the open position of the outlet valve 2. The rocker arm 13 is actuated by a camshaft 31, the camshaft 31 being connected to the rocker arm 13 via a plunger 43.

Parallel zum Ventilschaft 15 ist im Zylinderkopf 5 ein Stab 44 angeordnet, der mit seinem einen Ende in den Zylinderkopf 5 eingedreht ist. Der Stab 44 dient als Befestigung für einen Hilfskipphebel 42, der auf den Stab 44 aufgesetzt ist. Der Stab 44 weist an dem dem Zylinderkopf 5 abgewandten Ende zwei Muttern 45 auf, die zusammen mit einem Widerlager 4a als Anschlag für den Hilfskipphebel 42 dienen. Der Hilfskipphebel 42 wird durch eine Feder 46, die koaxial den Stab 44 umgibt, gegen die Muttern 45 gedrückt. Der Hilfskipphebel 42 ist dabei in der Art eines Waagebalkens und durch die Feder 46 ausserdem noch elastisch gelagert. Ein Arm 48 des Hilfskipphebels 42 ist U-förmig ausgebildet und liegt auf dem Ring 30a, der auf der Stirnseite des Ventilschafts 15 aufliegt, auf. Ein kugelförmiger Zapfen 47 des Kipphebels 13 ist innerhalb des U-förmigen Armes 48 des Hilfskipphebels 42 angeordnet und wirkt auf die zylindrische Erweiterung 30b des Ringes 30a ein.Parallel to the valve stem 15, a rod 44 is arranged in the cylinder head 5, which is screwed into the cylinder head 5 at one end. The rod 44 serves as a fastening for an auxiliary rocker arm 42 which is placed on the rod 44. At the end facing away from the cylinder head 5, the rod 44 has two nuts 45 which, together with an abutment 4a, serve as a stop for the auxiliary rocker arm 42. The auxiliary rocker arm 42 is pressed against the nuts 45 by a spring 46 which coaxially surrounds the rod 44. The auxiliary rocker arm 42 is in the manner of a balance beam and is also elastically supported by the spring 46. An arm 48 of the auxiliary rocker arm 42 is U-shaped and lies on the ring 30a, which is on the end face of the valve shaft 15 rests on. A spherical pin 47 of the rocker arm 13 is arranged within the U-shaped arm 48 of the auxiliary rocker arm 42 and acts on the cylindrical extension 30b of the ring 30a.

Der dem U-förmigen Arm 48 entgegengesetzte Arm des Hilfskipphebels 42 liegt auf einem Kolben 37 auf, der in einer zylindrischen Bohrung im Zylinderkopf 5 in seiner Axialrichtung bewegbar dichtend geführt ist. Die Bewegung des Kolbens 37 ist durch einen Anschlag 49 begrenzt. Der zum Abgaskanal 3 gewandte Boden des Kolbens 37 bildet eine Seite eines Druckraums 36 im Zylinderkopf 5, wobei der Druckraum 36 einen Einlass 39 und einen Auslass 40 aufweist. Der Einlass 39 wird von einer Ölleitung 34 der Brennkraftmaschine gebildet, die in den Ölkreislauf der Brennkraftmaschine integriert ist. In Strömungsrichtung vor dem Druckraum 36 ist in der ÖIleitung 34 eine Drossel 32 angeordnet, die den Durchfluss des Öls durch die Ölleitung 34 drosselt. Der Auslass 40 des Druckraums 36 geht in eine parallel zum Ventilschaft 15 angeordnete Bohrung 50 über, die einerseits mit dem Ventilraum bzw. Kipphebelraum verbunden ist und andererseits in einen Federraum 51 übergeht. Im Federraum 51 ist eine Membran 41 angeordnet, die den Federraum 51 von einem angrenzenden Gasraum 52 abteilt. Beide Räume sind durch die Membran 41 gasdicht voneinander getrennt. Auf der Membran 41 ist ein zylindrischer Steuerkolben 35 befestigt, der den Federraum 51 durchzieht und in die Bohrung 50 hineinragt. Der Steuerkolben 35 ist mit der Bewegung der Membran 41 gekoppelt und dichtet bei Ausdehnung der Membran 41 in Richtung Federraum 51 den Auslass 40 des Druckraums 36 ab. Im Federraum 51 ist koaxial um den Steuerkolben 35 eine Druckfeder 53 angeordnet, die die Membran 41 in Richtung Gasraum 52 kraftbeaufschlagt. Der Gasraum 52 ist durch eine Bohrung 54 mit dem Abgaskanal 3 verbunden.The arm of the auxiliary rocker arm 42 opposite the U-shaped arm 48 rests on a piston 37 which is movably sealingly guided in its axial direction in a cylindrical bore in the cylinder head 5. The movement of the piston 37 is limited by a stop 49. The bottom of the piston 37 facing the exhaust gas duct 3 forms one side of a pressure chamber 36 in the cylinder head 5, the pressure chamber 36 having an inlet 39 and an outlet 40. The inlet 39 is formed by an oil line 34 of the internal combustion engine, which is integrated in the oil circuit of the internal combustion engine. In the direction of flow upstream of the pressure chamber 36, a throttle 32 is arranged in the oil line 34, which throttles the flow of the oil through the oil line 34. The outlet 40 of the pressure chamber 36 merges into a bore 50 arranged parallel to the valve stem 15, which is connected on the one hand to the valve chamber or rocker arm chamber and on the other hand merges into a spring chamber 51. A membrane 41 is arranged in the spring chamber 51 and divides the spring chamber 51 from an adjacent gas chamber 52. Both spaces are separated from one another by the membrane 41 in a gastight manner. A cylindrical control piston 35 is attached to the diaphragm 41, which extends through the spring chamber 51 and projects into the bore 50. The control piston 35 is coupled to the movement of the membrane 41 and seals the outlet 40 of the pressure chamber 36 when the membrane 41 extends in the direction of the spring chamber 51. In the spring chamber 51, a compression spring 53 is arranged coaxially around the control piston 35 and acts upon the membrane 41 in the direction of the gas chamber 52. The gas space 52 is connected to the exhaust duct 3 through a bore 54.

Im Druckraum 36 ist ein Gegendruckventil angeordnet, welches aus einer federbelasteten Kugel 38 besteht, die in Schliessstellung des Gegendruckventils vom Öldruck im Druckraum 36 auf den Einlass 39 der Ölleitung 34 in den Druckraum 36 gepresst ist und diese verschliesst. Damit die Kugel 38 nur eine definierte axiale Lageänderung ausführt, ist sie von einer konisch geformten Feder 55 gehalten. Die Feder 55 stützt sich einerseits auf einem U-förmigen Bügel 56 im Druckraum 36 und andererseits auf der Kugel 38 ab.Arranged in the pressure chamber 36 is a counter pressure valve which consists of a spring-loaded ball 38 which, in the closed position of the counter pressure valve, is pressed from the oil pressure in the pressure chamber 36 onto the inlet 39 of the oil line 34 into the pressure chamber 36 and closes it. So that the ball 38 only performs a defined axial change in position, it is held by a conically shaped spring 55. The spring 55 is supported on the one hand on a U-shaped bracket 56 in the pressure chamber 36 and on the other hand on the ball 38.

Im Normalbetrieb der Brennkraftmaschine ist die Drosselklappe 9 im Abgaskanal 3 geöffnet, so dass sich kein hoher Gasdruck im Abgaskanal 3 aufbaut. Der Gasdruck im Abgaskanal 3, der über die Bohrung 54 auf die Membran 41 wirkt, reicht nicht aus, um diese entgegen der Kraft der Druckfeder 53 in Richtung Federraum 51 auszuwölben. Der Steuerkolben 35 verschliesst dadurch nicht den Auslass 40 des Druckraumes 36, so dass das durch die Ölleitung 34 hindurchfliessende Öl ungehindert durch den Druckraum 36 in den Ventil- bzw. Kipphebelraum gelangt.In normal operation of the internal combustion engine, the throttle valve 9 in the exhaust gas duct 3 is open, so that no high gas pressure builds up in the exhaust gas duct 3. The gas pressure in the exhaust duct 3, which acts on the diaphragm 41 via the bore 54, is not sufficient to bulge it against the force of the compression spring 53 in the direction of the spring chamber 51. As a result, the control piston 35 does not close the outlet 40 of the pressure chamber 36, so that the oil flowing through the oil line 34 passes unhindered through the pressure chamber 36 into the valve or rocker arm chamber.

Ist der Öldruck in der Ölleitung 34 in Strömungsrichtung hinter der Drossel 32 gross genug, so kann trotz des geöffneten Auslasses 40 der Kolben 37 bei geöffnetem Auslassventil 2 dem Öldruck nachgeben und seine Lage in Richtung Anschlag 49 verändern, und den Hilfskipphebel 42 derart anheben, dass der U-förmige Arm 48 des Hilfskipphebels 42 in Richtung Ventilsitz 7 ausgelenkt wird. Geht das Auslassventil 2 wieder in Schliessstellung, so geht der Hilfskipphebel 42 jedoch sofort wieder in seine ursprüngliche Lage zurück, da der Kolben 37 das Öl im Druckraum 36 durch den Auslass 40 in den Ventilraum bzw. Kipphebelraum drückt. Dieser Vorgang ist jedoch für die Wirkungsweise der erfindungsgemässen Motorbremsvorrichtung von untergeordneter Bedeutung und kann auch durch geeignete Abstimmung der Grösse des Auslasses 40 in Verbindung mit der Drossel 32 vermieden werden. Erfindungsgemäss ist von Bedeutung, dass im Normalbetrieb die Bewegung des Auslassventils 2 unbeeinflusst ist.If the oil pressure in the oil line 34 in the flow direction behind the throttle 32 is high enough, the piston 37 can yield to the oil pressure and change its position in the direction of the stop 49, and the auxiliary rocker arm 42, so that, despite the open outlet 40, the piston 37 the U-shaped arm 48 of the auxiliary rocker arm 42 is deflected in the direction of the valve seat 7. If the outlet valve 2 returns to the closed position, the auxiliary rocker arm 42 immediately returns to its original position, since the piston 37 presses the oil in the pressure chamber 36 through the outlet 40 into the valve chamber or rocker arm chamber. However, this process is of subordinate importance for the mode of operation of the engine brake device according to the invention and can also be avoided by suitably coordinating the size of the outlet 40 in connection with the throttle 32. It is important according to the invention that the movement of the outlet valve 2 is unaffected in normal operation.

Im Bremsbetrieb ist die Drosselklappe 9 im Abgaskanal 3 geschlossen, und der Gasdruck im Abgaskanal 3 reicht aus, um die Membran 41 mit dem daran befestigten Steuerkolben 37 entgegen der Kraft der Druckfeder 53 in Richtung Federraum 51 auszuwölben. Der Steuerkolben 37 verschliesst dann den Auslass 40 des Druckraumes 36. Ist das Auslassventil 2 gerade in Offenstellung, so fliesst Öl aus der Ölleitung 34 in den Druckraum 36 und schiebt den Kolben 37 bis zu einem Anschlag 49. Geht das Auslassventil 2 wieder in Schliessstellung über, so hebt der in Ruhestellung zurückgehende Ring 30a auf dem Ventilschaft 15 den U-förmigen Arm 48 des Hilfskipphebels 42 an und drückt dadurch den entgegengesetzten Arm auf den Kolben 37. Dadurch baut sich im Druckraum 36 sofort ein Druck auf, der den Einlass 39 mittels des Gegendruckventils schliesst, wenn der Druck im Druckraum 36 grösser ist als in der Ölleitung 34. Als Folge davon kann der Hilfskipphebel 42 nicht mehr in seine Ruhestellung zurückgehen, so dass auch das Auslassventil 2 in einer gewissen ausgelenkten Endlage verbleibt. Die Endlage des Auslassventils 2 ist so gewählt, dass der Ringspalt 4' zwischen Ventilteller 6 und Ventilsitz 7 des Auslassventils 2 im Verhältnis zum Querschnitt des Auslassventils 2 eine Drosselcharakteristik hat.In braking operation, the throttle valve 9 in the exhaust duct 3 is closed, and the gas pressure in the exhaust duct 3 is sufficient to bulge the diaphragm 41 with the control piston 37 attached thereto in the direction of the spring chamber 51 against the force of the compression spring 53. The control piston 37 then closes the outlet 40 of the pressure chamber 36. If the outlet valve 2 is just in the open position, oil flows from the oil line 34 into the pressure chamber 36 and pushes the piston 37 up to a stop 49. If the outlet valve 2 returns to the closed position , then the ring 30a returning to the rest position on the valve stem 15 lifts the U-shaped arm 48 of the auxiliary rocker arm 42 and thereby presses the opposite arm onto the piston 37. As a result, a pressure builds up in the pressure chamber 36, which pressures the inlet 39 of the back pressure valve closes when the pressure in the pressure chamber 36 is greater than in the oil line 34. As a result, the auxiliary rocker arm 42 can no longer return to its rest position, so that the outlet valve 2 also remains in a certain deflected end position. The end position of the exhaust valve 2 is selected such that the annular gap 4 ′ between the valve plate 6 and the valve seat 7 of the exhaust valve 2 has a throttle characteristic in relation to the cross section of the exhaust valve 2.

Die Einstellung des Ringspaltes 4' erfolgt demnach, durch den Gasdruck im Abgaskanal gesteuert, selbsttätig auf hydraulischem Wege. Ferner ist aufgrund der lmkompressibilität des Öls der den Drosselquerschnitt bestimmende Ringspalt 4' genau definierbar. Durch die Muttern 45 auf dem Stab 44 lässt sich die axiale Lage des Hilfskipphebels 42 und damit der Drosselquerschnitt des Ringkanals 4' auch nach dem Einbau der Brennkraftmaschine noch festlegen oder korrigieren.The setting of the annular gap 4 'is accordingly carried out automatically by hydraulic means, controlled by the gas pressure in the exhaust gas duct. Furthermore, due to the incompressibility of the oil, the annular gap 4 ′ which determines the throttle cross section can be precisely defined. The nuts 45 on the rod 44 allow the axial position of the auxiliary rocker arm 42 and thus the throttle cross section of the ring channel 4 'to be determined or corrected even after the internal combustion engine has been installed.

Claims (9)

1. An engine-braking system for an internal combustion engine, especially for a normally aspirated or a supercharged diesel engine, the engine having at least one combustion chamber (1) communicating via an outlet valve (2) with an exhaust flue (3) fitted with a butterfly valve (9) which is closed during braking, in which the combustion chamber (1) also communicates with the exhaust flue (31 via a further flue (4) which due to the size of its cross-section relative to that of the outlet valve (2) acts as a throttle and which is opened for the duration of braking but gastightly closed during normal engine operation by a valve (8) actuatable by an adjusting device, characterized in that the gas pressure prevailing in the exhaust flue (3) is arranged to act on the adjusting device (19) in such a way that it actuates the valve (8) which opens the further flue (4) if the butterfly valve (9) is closed.
2. An engine-braking system according to claim 1, characterized in that the valve (8) is connected to a spring-loaded piston (10) disposed in the adjusting device (19), and in that the gas pressure prevailing in the exhaust flue (3) upstream of the butterfly valve (9) is arranged to act on the piston's one effective piston face so as to open the valve (8) against the bias of the spring (26).
3. An engine-braking system for an internal combustion engine, especially for a normally aspirated or a supercharged diesel engine, the engine having a combustion chamber (1) communicating via at least one outlet valve (2) with an exhaust flue (3), in which for the duration of braking an annular gap (4') is formed between the valve head (6) and the valve seat (7) of the outlet valve (2), and in which the annular gap is controlled by a hydraulic adjusting device forming part of the oil circuit of the engine, characterized in that the exhaust flue (3) is provided with a butterfly valve which is closed during braking, and in thatthe annular gap's (4') adjustement which is controlled by the gas pressure prevailing in the exaust flue (3) is automatic.
4. An engine-braking system according to claim 3, characterized in that the adjusting device includes a pressure chamber (36) closable, on the one side, by a counterpressure valve and, on the other side, by a control piston (35) and is arranged in an oil duct (34) leading to a box accommodating a rocker arm and the outlet valve respectively, and in that one end of the pressure chamber is defined by a piston (37) axially movable and sealingly guided in a cylinder.
5. An engine-braking system according to claim 4, characterized in that the counterpressure valve is a spring-loaded ball (38) arranged in the pressure chamber (36), and in that the ball, in the closing position of the counterpressure valve, is forced by the oil pressure prevailing in the pressure chamber (36) against the oil duct's (34) inlet (39) into the pressure chamber (36) and closes it.
6. An engine-braking system according to claim 4, characterized in that the control piston (35) is joined at its end portion remote from the pressure chamber (36) to a diaphragm (41), and in thatthe gas pressure prevailing in the exhaust flue (3) acts against the bias of a spring upon the diaphragm in such a way that, during engine-braking, the diaphragm (41) including the control piston (35) are displaced against the bias of the spring and that the control piston (35) closes the other side of the pressure chamber (36).
7. An engine-braking system according to any of the claims 4to 6, characterized in thatthe piston (37) holds, through an auxiliary adjusting device, the outlet valve (2) in its inoperative position which is one of its end positions.
8. An engine-braking system according to claim 7, in which the valve head (6) of the outlet valve (2) is joined to a valve stem (15), characterized in that the auxiliary adjusting device is an auxiliary rocker arm (42) one end of which interacts with the piston (37) and its other with the valve stem (15).
9. An engine-braking system according to claim 8, characterized in that the axial position of the auxiliary rocker arm (42) is adjustable.
EP86102326A 1985-02-27 1986-02-22 Engine-braking system for an internal-combustion engine Expired EP0193142B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3506894 1985-02-27
DE19853506894 DE3506894A1 (en) 1985-02-27 1985-02-27 ENGINE BRAKE DEVICE FOR INTERNAL COMBUSTION ENGINES

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EP0193142A1 EP0193142A1 (en) 1986-09-03
EP0193142B1 true EP0193142B1 (en) 1988-04-20

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US8776738B2 (en) 1997-12-11 2014-07-15 Jacobs Vehicle Systems, Inc Variable lost motion valve actuator and method
US8820276B2 (en) 1997-12-11 2014-09-02 Jacobs Vehicle Systems, Inc. Variable lost motion valve actuator and method

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DE3660138D1 (en) 1988-05-26
EP0193142A1 (en) 1986-09-03
DE3506894A1 (en) 1986-08-28

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