EP0068336B1 - Two-cylinder four-stroke boxer engine, particularly for a motor cyle, cooled by the oncoming air flux - Google Patents

Two-cylinder four-stroke boxer engine, particularly for a motor cyle, cooled by the oncoming air flux Download PDF

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Publication number
EP0068336B1
EP0068336B1 EP82105324A EP82105324A EP0068336B1 EP 0068336 B1 EP0068336 B1 EP 0068336B1 EP 82105324 A EP82105324 A EP 82105324A EP 82105324 A EP82105324 A EP 82105324A EP 0068336 B1 EP0068336 B1 EP 0068336B1
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EP
European Patent Office
Prior art keywords
crank
shaft
cylinder
valves
boxer engine
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
EP82105324A
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German (de)
French (fr)
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EP0068336A1 (en
Inventor
Jiri Dipl.-Ing. Seidl
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Bayerische Motoren Werke AG
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Bayerische Motoren Werke AG
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Publication date
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Priority to DE8383112438T priority Critical patent/DE3273260D1/en
Publication of EP0068336A1 publication Critical patent/EP0068336A1/en
Application granted granted Critical
Publication of EP0068336B1 publication Critical patent/EP0068336B1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
    • F02F1/4214—Shape or arrangement of intake or exhaust channels in cylinder heads specially adapted for four or more valves per cylinder
    • 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/022—Chain drive
    • 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/024—Belt drive
    • 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per 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
    • F02B61/00—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing
    • F02B61/02—Adaptations of engines for driving vehicles or for driving propellers; Combinations of engines with gearing for driving cycles
    • 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
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F02B75/18—Multi-cylinder engines
    • F02B75/22—Multi-cylinder engines with cylinders in V, fan, or star arrangement
    • 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
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F02B75/18—Multi-cylinder engines
    • F02B75/24—Multi-cylinder engines with cylinders arranged oppositely relative to main shaft and of "flat" type
    • F02B75/243—Multi-cylinder engines with cylinders arranged oppositely relative to main shaft and of "flat" type with only one crankshaft of the "boxer" type, e.g. all connecting rods attached to separate crankshaft bearings
    • 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/047—Camshafts
    • F01L1/053—Camshafts overhead type
    • F01L2001/0535—Single overhead camshafts [SOHC]
    • 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
    • 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
    • F02B1/00—Engines characterised by fuel-air mixture compression
    • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
    • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into 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
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
    • 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
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F02B75/18—Multi-cylinder engines
    • F02B2075/1804—Number of cylinders
    • F02B2075/1808—Number of cylinders two
    • 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
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/20—SOHC [Single overhead camshaft]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/244—Arrangement of valve stems in cylinder heads
    • F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis

Definitions

  • the invention relates to a two-cylinder four-stroke boxer engine of a type according to the features specified in the preamble of claim 1.
  • a known boxer engine of this type according to D E-A No. 2703520 has a relatively jagged outer shape, which is derived in particular from the arrangement of the valves and their drives. This is because the intermediate shaft for driving the two overhead cam shafts is arranged above the crankshaft and the chain and belt drives extend with separate covers arranged at a distance from the cylinders and cylinder heads to control housings projecting from the cylinder head.
  • the arrangement of parallel intake and exhaust valves also contributes to the asymmetrical and jagged design of this boxer engine.
  • the housing parts which protrude considerably beyond the basic contour of the cylinders and cylinder heads, also result in high construction costs with a correspondingly high weight.
  • the object of the invention is to avoid the aforementioned disadvantages and to create a boxer engine on the basis of the known design, which has a compact overall structure with low construction costs and light weight, favorable conditions for good ground clearance when installed in motorcycles, an efficient and speed-resistant control system V-valve arrangement, a largely smooth, easy-to-clean and appealing outer shape and finally, in the case of airstream air cooling, has a favorable cooling air flow on the cylinders and cylinder heads.
  • the invention provides an arrangement according to the characterizing part of patent claim 1.
  • a known boxer engine according to FR-A No. 818196 already has a pump wheel of a lubricating oil pump on a shaft below the crankshaft.
  • this shaft is designed as a camshaft for direct actuation of valves arranged laterally in the combustion chamber and guided in the cylinders.
  • the design of this design differs so significantly from that of the invention that no suggestion for the overall combination of the features of the invention can be derived from it.
  • the arrangement of the intake valves according to claim 4 results in a favorable position for the combustion process and maintenance of the spark plugs in the center of the combustion chamber or on the top of the cylinder heads, without reducing the aforementioned advantages.
  • the features of claim 8 accordingly include a corresponding weight and space-saving design and arrangement of the balancing masses.
  • the feature of claim 11 results in a space requirement of the spark plug, which avoids an excessive distance between the inlet valves and their valve springs.
  • the intermediate shaft 4 drives both a lubricating oil pump 12, of which a pump wheel 12 ′ is fastened on the intermediate shaft 4, and also two chain drives 13, each for an overhead cam shaft 14.
  • a lubricating oil pump 12 of which a pump wheel 12 ′ is fastened on the intermediate shaft 4
  • two chain drives 13 each for an overhead cam shaft 14.
  • the filter insert 16 of which is accessible for maintenance work through an internal cover 17.
  • the cover 17, the toothed belt drive 7, 8 and 9 and the generator 6 are protected against environmental influences by a largely smooth end wall cover 18, which at the same time favors the cleaning of the end face of the crankcase 2.
  • the flywheel 5 is framed by a mounting flange 19 for the connection of a transmission housing, not shown.
  • a circumferential fastening flange 20 with a number of fastening eyes 21 for fastening screws 22 is integrally formed on the top of the crankcase 2, with which a frame sheet metal hollow body 23 is screwed.
  • a crankcase ventilation opening 24 opens out.
  • the frame sheet metal hollow body 23 connects the crankcase 2 on a broad, rigid base to a control head 25 of a motorcycle.
  • the frame sheet metal hollow body 23 On its end face, the frame sheet metal hollow body 23 carries an intake air filter 26, through which the filtered intake air flows through openings 27 into the interior of the frame sheet metal hollow body 23.
  • This serves as an intake chamber for the combustion air of the engine and contains intake pipes 28 which are matched in length and which each feed the combustion air to a carburetor 29.
  • the carburetors 29 are partially inside indentations 30 of the hollow sheet metal body 23, which has sealed through openings 31 for the passage of the intake pipes 28 inside the indentations 30.
  • a cylinder 32 is flanged on both sides of the crankcase 2, and a cylinder head 33, each with a cylinder head cover 34, is flanged to each of these.
  • Cylinder 32, cylinder head 33 and cylinder head cover 34 have numerous cooling fins 35 for airflow air cooling. It en hold t quantities that a tunnel 36 for receiving the chain drives 13, as seen from the intermediate shaft 4 in the crankcase 2 to the camshaft 14 in the cylinder heads 33- in the driving direction - extend to the rear of the cylinder 32 and the cylinder heads 33rd
  • the chain drives 13 have a 1: 1 transmission, so that small sprockets 13 'can be used both on the intermediate shaft 4 and on the camshafts 14.
  • valve control for two intake valves 37 and one exhaust valve 38 by means of three rocker arms 39 as transmission elements from the camshaft 14 to the valves 37 and 38 has a somewhat larger side projection, so that the cylinder head cover 34 has a protrusion-free outer shape rounded on all sides have. This favors both their external appearance and their easy cleaning as well as the small overall width of the boxer engine and also the motorcycle equipped with it (Fig. 2 and 3).
  • valves 37 and 38 are arranged in the vertical V position.
  • the two inlet valves 37 lie parallel to one another, corresponding to a V-leg, which is determined by the plane of the two inlet valves 37 and, as viewed towards the end of the inlet valve 37, has an upward inclination of approximately 37 °.
  • the V-leg determined by the outlet valves 38 on the other hand, has a corresponding downward inclination of approximately 15 °.
  • the camshafts are each in an angle bisecting position within the approx. 52 ° V position of valves 37 and 38.
  • the rocker arms 39 for driving a valve 37 or 38 are rotatably arranged on bearing axes 40.
  • Their pivot bearing sections 41 are arranged eccentrically to their firmly clamped axle journals 42 for the valve clearance adjustment (FIGS. 2 and 5).
  • Their axle journals 42 can be clamped non-rotatably in bearing seats 44 of the cylinder head 33 which can be clamped by means of screws 43.
  • the bearing axles 40 have a key profile formed on an accessible front end, which cannot be seen in the drawing. An inner profile is preferred because it does not require space and saves weight as a material recess. The valve control thus requires little space and construction and does not contain any additional moving parts for the valve clearance adjustment.
  • valve plates 37 'and 38' of the inlet 37 and the outlet valves 38 are almost tangentially close to the associated circular contour 32 'of the associated cylinder 32 and at a relatively close distance between the valve plate 37' and each valve plate 38 '.
  • the spark gap of the spark plug 45 is located centrally between the valves 37 and 38 in the combustion chamber 46.
  • a large squeeze area 47 can be formed enables a pinch gap with a favorable influence on the combustion process in cooperation with a flat bottom portion of a piston 48.
  • the spark plug 45 is arranged at a steeper inclination than the inlet valves 37 in the vertical plane 49 together with the outlet valve 38.
  • the installation space requirement of the spark plug comes as a result not between the space requirements of the valve springs 50 of the inlet valves 37.
  • the spark plugs and their electrical connections are particularly conveniently accessible for maintenance.
  • an open horizontal cooling air duct 51 is formed, as seen in the direction of travel. This ends at its end opposite to the direction of travel in a vertical outflow shaft 52 which is arranged in front of the tunnel 36 of the chain drive 13 and is open at the top and bottom.
  • a favorable space-saving arrangement results from the valve arrangement described above also for the intake manifold 28 'with the carburetors 29 and for the exhaust pipes 53. While the suction system on the top of the engine rests closely on the frame sheet metal hollow body 23 in a space-saving manner and therefore has a small width there is sufficient space available for routing the exhaust pipes 53 with relatively large, low flow resistance radii, without impairing the ground - and the inclined freedom for motorcycle riding.
  • the overall structure of the two-cylinder, four-stroke boxer engine according to the invention results, especially for use in motorcycles, in a summation of mutually complementary advantages with regard to high performance, effective cooling, good running properties, low weight and construction expenditure, small space requirement and appealing external shape.
  • most of these advantages also come into play in stationary and / or encapsulated applications with forced air or liquid cooling.

Description

Die Erfindung bezieht sich auf einen Zweizylinder-Viertakt-Boxermotor einer Bauart gemäss den im Oberbegriff des Patentanspruches 1 angegebenen Merkmalen.The invention relates to a two-cylinder four-stroke boxer engine of a type according to the features specified in the preamble of claim 1.

Ein bekannter Boxermotor dieser Bauart nach der D E-A Nr. 2703520 weist eine verhältnismässig zerklüftete äussere Form auf, die sich insbesondere aus der Anordnung der Ventile und deren Antriebes herleitet. Dabei ist nämlich die Zwischenwelle für den Antrieb der beiden obenliegenden Nokkenwellen über der Kurbelwelle angeordnet und die Ketten- bzw. Riementriebe erstrecken sich mit gesonderten, im Abstand von den Zylindern und Zylinderköpfen angeordneten Abdeckungen zu jeweils vom Zylinderkopf abstehenden Steuergehäusen. Die Anordnung jeweils paralleler Ein- und Auslassventile trägt gleichfalls zum unsymmetrischen und zerklüfteten Aufbau dieses Boxermotors bei. Darüber hinaus ergibt sich aus den über die Grundkontur der Zylinder und Zylinderköpfe erheblich hinausragenden Gehäuseteilen auch ein hoher Bauaufwand mit entsprechend hohem Gewicht.A known boxer engine of this type according to D E-A No. 2703520 has a relatively jagged outer shape, which is derived in particular from the arrangement of the valves and their drives. This is because the intermediate shaft for driving the two overhead cam shafts is arranged above the crankshaft and the chain and belt drives extend with separate covers arranged at a distance from the cylinders and cylinder heads to control housings projecting from the cylinder head. The arrangement of parallel intake and exhaust valves also contributes to the asymmetrical and jagged design of this boxer engine. In addition, the housing parts, which protrude considerably beyond the basic contour of the cylinders and cylinder heads, also result in high construction costs with a correspondingly high weight.

Aufgabe der Erfindung ist es, die vorgenannten Nachteile zu vermeiden und auf der Grundlage der bekannten Bauart einen Boxermotor zu schaffen, der einen kompakten Gesamtaufbau mit geringem Bauaufwand und geringem Gewicht, günstige Voraussetzungen für gute Bodenfreiheit beim Einbau in Motorräder, eine leistungsgünstige und drehzahlfeste Steuerung mit V-Ventilanordnung, eine weitgehend glatte, reinigungsgünstige und ansprechende äussere Form sowie schliesslich bei Fahrtwind-Luftkühlung eine günstige Kühlluftströmung an den Zylindern und Zylinderköpfen aufweist.The object of the invention is to avoid the aforementioned disadvantages and to create a boxer engine on the basis of the known design, which has a compact overall structure with low construction costs and light weight, favorable conditions for good ground clearance when installed in motorcycles, an efficient and speed-resistant control system V-valve arrangement, a largely smooth, easy-to-clean and appealing outer shape and finally, in the case of airstream air cooling, has a favorable cooling air flow on the cylinders and cylinder heads.

Zur Lösung dieser vielseitigen Aufgabe sieht die Erfindung eine Anordnung gemäss dem Kennzeichen des Patentanspruches 1 vor. Durch diese Merkmale wird die gestellte Aufgabe der Erfindung in überraschend günstiger Weise gelöst. Der Ventilantrieb einschliesslich Ölpumpenantrieb erfordert durch diese Merkmale einen äusserst geringen Raumbedarf ohne von der Grundkontur der Motorbauteile vorspringende Gehäuseteile oder Abdeckungen. Die Ventil-, Nockenwellen- und Gaswechselkanal-Anordnungen führen gleichfalls zu einem sehr kompakten Gesamtaufbau des Boxermotors mit eng an die Aussenkonturen anliegenden Führungen der Ansaug- und Abgassysteme auf der Oberseite bzw. Unterseite der Zylinder und Zylinderköpfe.To achieve this versatile object, the invention provides an arrangement according to the characterizing part of patent claim 1. These features achieve the object of the invention in a surprisingly favorable manner. Due to these features, the valve drive including the oil pump drive requires an extremely small amount of space without housing parts or covers projecting from the basic contour of the engine components. The valve, camshaft and gas exchange duct arrangements likewise lead to a very compact overall construction of the boxer engine with guides of the intake and exhaust systems closely fitting to the outer contours on the top and bottom of the cylinders and cylinder heads.

Ein bekannter Boxermotor gemäss der FR-A Nr. 818196 weist zwar bereits ein Pumpenrad einer Schmierölpumpe auf einer Welle unterhalb der Kurbelwelle auf. Dabei ist diese Welle jedoch als Nockenwelle für die unmittelbare Betätigung im Brennraum seitlich stehend angeordneter und in den Zylindern geführter Ventile ausgebildet. Diese Ausbildung weicht in ihrer Bauart so erheblich von derjenigen der Erfindung ab, dass aus ihr keineAnregung für die Gesamtkombination der Erfindungsmerkmale abgeleitet werden kann.A known boxer engine according to FR-A No. 818196 already has a pump wheel of a lubricating oil pump on a shaft below the crankshaft. In this case, however, this shaft is designed as a camshaft for direct actuation of valves arranged laterally in the combustion chamber and guided in the cylinders. The design of this design differs so significantly from that of the invention that no suggestion for the overall combination of the features of the invention can be derived from it.

Durch die Merkmale des Anspruches 2 werden die zum Anspruch 1 zuletzt genannten Anordnungen noch weiter begünstigt, so dass sich die Ansauganlagen auf der Oberseite der Zylinder und Zylinderköpfe beider Seiten noch enger annähern und insgesamt einen noch geringeren Platzbedarf aufweisen, während den Abgasleitungen an der Unterseite der Zylinder und Zylinderköpfe mehr Raum für eine der Bodenfreiheit bei Motorrädern zugute kommende Führung der Abgasleitungen zur Fahrzeugmitte hin zur Verfügung gestellt wird.Due to the features of claim 2, the arrangements mentioned last for claim 1 are further favored, so that the intake systems on the top of the cylinders and cylinder heads come closer on both sides and have an overall smaller space requirement, while the exhaust pipes on the underside of the Cylinders and cylinder heads provide more space for routing the exhaust pipes to the center of the vehicle, which benefits the ground clearance of motorcycles.

Die Verwendung zweier Einlassventile und eines Auslassventiles nach Anspruch 3 ermöglicht gegenüber je einem Ein- und Auslassventil grössere Ventilzeitquerschnitte bei relativ kleinem V-Winkel der Ventile, was den vorgenannten räumlichen Vorteilen weiter zugute kommt und darüber hinaus die Leistung und den Drehzahlbereich des Motors erhöht bzw. erweitert sowie eine unterschiedliche Teillast-Steuerung beider Einlasskanäle ermöglicht.The use of two intake valves and one exhaust valve according to claim 3 enables larger valve time cross-sections with a relatively small V-angle of the valves compared to one intake and one exhaust valve, which further benefits the aforementioned spatial advantages and further increases the power and speed range of the engine or expanded and enables a different partial load control of both inlet channels.

Die Anordnung der Einlassventile nach Anspruch 4 ergibt eine für den Verbrennungsablauf und die Wartung günstige Lage der Zündkerzen in Brennraummitte bzw. an der Oberseite der Zylinderköpfe, ohne dass die vorgenannten Vorteile verringert werden.The arrangement of the intake valves according to claim 4 results in a favorable position for the combustion process and maintenance of the spark plugs in the center of the combustion chamber or on the top of the cylinder heads, without reducing the aforementioned advantages.

Die Merkmale des Anspruches 5 begünstigen sowohl die Drehzahlfestigkeit der Ventilsteuerung durch die sehr geringe bewegte Masse der Kipphebel als auch die Baubreite und die Bodenfreiheit für Motorradeinbau des Motors durch die geringe Bauhöhe der Ventilsteuerung über den Ventilschaftenden.The features of claim 5 favor both the speed stability of the valve control due to the very small moving mass of the rocker arm as well as the width and the ground clearance for motorcycle installation of the engine due to the low height of the valve control over the valve stem ends.

Durch die Merkmale des Anspruches 6 wird die Fahrtwind-Luftkühlung des Zylinderkopfes begünstigt, ohne hierbei die übrigen Vorteile der Erfindung negativ zu beeinflussen.Due to the features of claim 6, the airstream air cooling of the cylinder head is favored without adversely affecting the other advantages of the invention.

Die Merkmale des Anspruches 7 ergeben einerseitseinen sehr geringen Lagerabstand der Kurbelwellenlager und damit geringe Biegemomente aus den Kurbelkräften mit daraus entsprechend geringen Durchbiegungen der Kurbelwelle. Andererseits ist der Hebelarm der Ausgleichsmassen relativ gross, wodurch diese klein gehalten werden können und damit auch das Motor-Gesamtgewicht verringert ist.The features of claim 7 on the one hand result in a very small bearing spacing of the crankshaft bearings and thus low bending moments from the crank forces with correspondingly low deflections of the crankshaft. On the other hand, the lever arm of the balancing masses is relatively large, which means that they can be kept small and thus the overall engine weight is reduced.

Die Merkmale des Anspruches 8 beinhalten demgemäss eine entsprechend gewichts- und raumsparende Ausbildung und Anordnung der Ausgleichsmassen.The features of claim 8 accordingly include a corresponding weight and space-saving design and arrangement of the balancing masses.

Die Merkmale des Anspruches 9 ergeben einen einfach abdichtbaren Anschluss mit verteilter Kräfteeinleitung von einem Rahmen-Blechhohlträger in das Kurbelgehäuse, wobei sich Leitungen für die Kurbelgehäuse-Entlüftung erübrigen, wenn der Rahmen-Blechhohlkörper als Ansaugraum für die Verbrennungsluft des Motors dient.The features of claim 9 result in an easily sealable connection with distributed introduction of force from a hollow frame support into the crankcase, wherein lines for the crankcase ventilation are unnecessary if the hollow frame body serves as an intake chamber for the combustion air of the engine.

Die Merkmale des Anspruches 10 ergeben eine Anordnung des Verschlussdeckels für einen Ölfilter, die einen sonst üblichen zerklüfteten Aussenwandteil mit Schmutzecken vermeidet. Die Zugänglichkeit für den Ölfilter-Wechsel ist trotzdem unverändert beibehalten, weil bei Wartungsarbeiten der Stirnwand-Deckel üblicherweise sowieso abgenommen werden muss, um andere Nebenaggregate zu überprüfen.The features of claim 10 result in an arrangement of the cover for an oil filter, which avoids an otherwise usual jagged outer wall part with dirt corners. The accessibility for changing the oil filter is still unchanged because the bulkhead cover is usually used anyway for maintenance work must be removed to check other ancillary units.

Das Merkmal des Anspruches 11 ergibt einen Raumbedarf der Zündkerze, der einen zu grossen Abstand der Einlassventile und deren Ventilfedern vermeidet.The feature of claim 11 results in a space requirement of the spark plug, which avoids an excessive distance between the inlet valves and their valve springs.

In der Zeichnung ist ein Ausführungsbeispiel der Erfindung dargestellt. Es zeigen:

  • Fig. 1 einen Längsschnitt eines fahrtwind-luftgekühlten Zweizylinder-Viertakt-Boxermotors für Motorräder mit an der Oberseite des Kurbelgehäuses angeflanschtem Rahmen-Blechhohlkörper in schematischer Darstellung,
  • Fig. 2 eine teilweise geschnittene Stirnansicht gemäss Pfeil II in Fig. 1,
  • Fig. 3 die teilweise geschnittene Draufsicht gemäss der Linie III-III in Fig. 2,
  • Fig. 4 die Innenansicht des Brennraumes im Zylinderkopf mit Ventil- und Zündkerzenanordnung gemäss der Linie IV-IV in Fig. 3,
  • Fig. 5 die Draufsicht auf die offenliegende Ventilsteuerung gemäss der Linie V-V in Fig. 3, und
  • Fig. 6 den Längsschnitt durch den Kühlluftkanal im Zylinderkopf nach der Linie VI-VI in Fig. 3. Ein fahrtwind-luftgekühlter Zweizylinder-Viertakt-Boxermotor 1 weist ein in seiner vertikalen Längsmittenebene I-I geteiltes Kurbelgehäuse 2 auf. In Fig. 1 ist demgemäss der Längsschnitt im Bereich des Kurbelgehäuses durch Weglassen seiner einen Hälfte gebildet. In der Längsmittenebene I-I ist sowohl eine einteilige Kurbelwelle 3 als auch eine Zwischenwelle 4 in Gleitlagern gelagert. Die Kurbelwelle 3 trägt an ihrem abtriebsseitigen Ende ein Schwungrad 5 und an ihrem gegenüberliegenden vorderen Ende einen Generator 6 sowie ein Zahnriemenrad 7 für die 1:2-untersetzte Antriebsverbindung mittels eines Zahnriemens 8 und eines weiteren Zahnriemenrades 9 zur Zwischenwelle 4. Beiderseits ihrer Hubkurbeln 3' und ausserhalb ihrer Hauptlager 10 ist der Kurbelwelle 3 je eine relativ schmale scheibenförmige Ausgleichsmasse 11 angeformt, die in entsprechend engen Ringräumen 2' des Kurbelgehäuses 2 zwischen den Hauptlagern 10 und anschliessenden Wellendichtungen 10' angeordnet sind. Durch den relativ grossen Abstand der Ausgleichsmassen 11 wird deren Ausgleichsfunktion verstärkt bzw. deren Gewicht reduziert. Durch deren Anordnung wird der Abstand der Hauptlager 10 und damit das Gewicht des Kurbelgehäuses 2 verringert.
In the drawing, an embodiment of the invention is shown. Show it:
  • 1 shows a longitudinal section of a wind-air-cooled two-cylinder four-stroke boxer engine for motorcycles with a hollow sheet metal frame flanged to the top of the crankcase, in a schematic illustration,
  • 2 is a partially sectioned end view according to arrow II in FIG. 1,
  • 3 shows the partially sectioned top view according to line III-III in FIG. 2,
  • 4 shows the interior view of the combustion chamber in the cylinder head with valve and spark plug arrangement according to line IV-IV in FIG. 3,
  • Fig. 5 is a plan view of the open valve control along the line VV in Fig. 3, and
  • 6 shows the longitudinal section through the cooling air duct in the cylinder head along the line VI-VI in FIG. 3. An air-cooled, air-cooled two-cylinder four-stroke boxer engine 1 has a crankcase 2 divided in its vertical longitudinal center plane II. In Fig. 1, the longitudinal section is accordingly formed in the region of the crankcase by omitting one half. In the longitudinal center plane II, both a one-piece crankshaft 3 and an intermediate shaft 4 are mounted in plain bearings. The crankshaft 3 carries a flywheel 5 at its output end and a generator 6 and a toothed belt wheel 7 for the 1: 2 reduced drive connection by means of a toothed belt 8 and a further toothed belt wheel 9 to the intermediate shaft 4 on its opposite front end. Both sides of their lifting cranks 3 ' and outside of their main bearings 10, the crankshaft 3 is each formed with a relatively narrow disc-shaped compensating mass 11, which are arranged in correspondingly narrow annular spaces 2 'of the crankcase 2 between the main bearings 10 and subsequent shaft seals 10'. Due to the relatively large distance between the balancing masses 11, their balancing function is strengthened or their weight is reduced. By their arrangement, the distance between the main bearings 10 and thus the weight of the crankcase 2 is reduced.

Die Zwischenwelle 4 treibt sowohl eine Schmierölpumpe 12, von der ein Pumpenrad 12' auf der Zwischenwelle 4 befestigt ist, als auch zwei Kettentriebe 13 zu je einer obenliegenden Nokkenwelle 14 an. Im Kurbelgehäuse 2 ist ferner ein Ölfilter 15 angeordnet, dessen Filtereinsatz 16 zu Wartungsarbeiten durch einen innenliegenden Deckel 17 zugänglich ist. Der Deckel 17, der Zahnriementrieb 7, 8 und 9 und der Generator 6 sind von einem weitgehend glattflächigen Stirnwand-Deckel 18 gegen Umwelteinflüsse geschützt, der zugleich die Reinigung der Stirnfläche des Kurbelgehäuses 2 begünstigt.The intermediate shaft 4 drives both a lubricating oil pump 12, of which a pump wheel 12 ′ is fastened on the intermediate shaft 4, and also two chain drives 13, each for an overhead cam shaft 14. In the crankcase 2 there is also an oil filter 15, the filter insert 16 of which is accessible for maintenance work through an internal cover 17. The cover 17, the toothed belt drive 7, 8 and 9 and the generator 6 are protected against environmental influences by a largely smooth end wall cover 18, which at the same time favors the cleaning of the end face of the crankcase 2.

An der Rückseite des Kurbelgehäuses 2 ist das Schwungrad 5 von einem Befestigungsflansch 19 für den Anschluss eines nicht dargestellten Getriebegehäuses umrahmt. Der Oberseite des Kurbelgehäuses 2 ist ein umlaufender Befestigungsflansch 20 mit einer Anzahl Befestigungsaugen 21 für Befestigungsschrauben 22 angeformt, mit denen ein Rahmen-Blechhohlkörper 23 verschraubt ist. innerhalb der vom Befestigungsflansch 20 umrahmten Oberseite des Kurbelgehäuses 2 mündet eine Kurbelgehäuse-Entlüftungsöffnung 24 aus. Der Rahmen-Blechhohlkörper 23 verbindet das Kurbelgehäuse 2 auf breiter biegesteifer Basis mit einem Steuerkopf 25 eines Motorrades. An seiner Stirnseite trägt der Rahmen-Blechhohlkörper 23 einen Ansaug-Luftfilter 26, durch den die gefilterte Ansaugluft über Öffnungen 27 in das Innere des Rahmen-Blechhohlkörpers 23 strömt. Dieses dient als Ansaugraum für die Verbrennungsluft des Motors und enthält in ihrer Länge abgestimmte Ansaugrohre 28, die die Verbrennungsluft je einem Vergaser 29 zuleiten. Die Vergaser 29 liegen teilweise innerhalb von Einbuchtungen 30 des Rahmen-Blechhohlköpers 23, der für den Durchtritt der Ansaugrohre 28 innerhalb der Einbuchtungen 30 abgedichtete Druchtrittsöffnungen 31 aufweist.At the rear of the crankcase 2, the flywheel 5 is framed by a mounting flange 19 for the connection of a transmission housing, not shown. A circumferential fastening flange 20 with a number of fastening eyes 21 for fastening screws 22 is integrally formed on the top of the crankcase 2, with which a frame sheet metal hollow body 23 is screwed. Within the upper side of the crankcase 2 framed by the fastening flange 20, a crankcase ventilation opening 24 opens out. The frame sheet metal hollow body 23 connects the crankcase 2 on a broad, rigid base to a control head 25 of a motorcycle. On its end face, the frame sheet metal hollow body 23 carries an intake air filter 26, through which the filtered intake air flows through openings 27 into the interior of the frame sheet metal hollow body 23. This serves as an intake chamber for the combustion air of the engine and contains intake pipes 28 which are matched in length and which each feed the combustion air to a carburetor 29. The carburetors 29 are partially inside indentations 30 of the hollow sheet metal body 23, which has sealed through openings 31 for the passage of the intake pipes 28 inside the indentations 30.

Dem Kurbelgehäuse 2 sind beiderseits je ein Zylinder 32 und diesen wiederum je ein Zylinderkopf 33 mit je einem Zylinderkopf-Deckel 34 angeflanscht. Zylinder 32, Zylinderkopf 33 und Zylinderkopf-Deckei 34 weisen zur Fahrtwind-Luftkühlung zahlreiche Kühlrippen 35 auf. Sie enthalten ferner je einen Tunnel 36 zur Aufnahme der Kettentriebe 13, die sich von der Zwischenwelle 4 im Kurbelgehäuse 2 zu den Nockenwellen 14 in den Zylinderköpfen 33- in Fahrtrichtung gesehen - auf der Rückseite der Zylinder 32 und der Zylinderköpfe 33 erstrecken. Die Kettentriebe 13 weisen eine 1 :1-Übertragung auf, wodurch sich sowohl auf der Zwischenwelle 4 als auch auf den Nockenwellen 14 kleine Kettenräder 13' verwenden lassen. Diese erfordern auch in den Zylinderköpfen 33 und den Zylinderkopf-Deckeln 34 einen geringen Platzbedarf. Die Ventilsteuerung für jeweils zwei Einlassventile 37 und ein Auslassventil 38 mittels dreier Kipphebel 39 als Übertragungselemente von der Nockenwelle 14 zu den Ventilen 37 und 38 weist demgegenüber eine etwas grössere Seitenausladung auf, so dass die Zylinderkopf-Deckel 34 eine nach allen Seiten hin abgerundete vorsprungsfreie Aussenform besitzen. Dies begünstigt sowohl deren äusseres Erscheinungsbild als auch deren leichte Reinigung sowie ferner die geringe Gesamtbaubreite des Boxermotors und auch des damit ausgerüsteten Motorrades (Fig. 2 und 3).A cylinder 32 is flanged on both sides of the crankcase 2, and a cylinder head 33, each with a cylinder head cover 34, is flanged to each of these. Cylinder 32, cylinder head 33 and cylinder head cover 34 have numerous cooling fins 35 for airflow air cooling. It en hold t quantities that a tunnel 36 for receiving the chain drives 13, as seen from the intermediate shaft 4 in the crankcase 2 to the camshaft 14 in the cylinder heads 33- in the driving direction - extend to the rear of the cylinder 32 and the cylinder heads 33rd The chain drives 13 have a 1: 1 transmission, so that small sprockets 13 'can be used both on the intermediate shaft 4 and on the camshafts 14. These also require a small amount of space in the cylinder heads 33 and the cylinder head covers 34. The valve control for two intake valves 37 and one exhaust valve 38 by means of three rocker arms 39 as transmission elements from the camshaft 14 to the valves 37 and 38, on the other hand, has a somewhat larger side projection, so that the cylinder head cover 34 has a protrusion-free outer shape rounded on all sides have. This favors both their external appearance and their easy cleaning as well as the small overall width of the boxer engine and also the motorcycle equipped with it (Fig. 2 and 3).

Die Ventile 37 und 38 sind in vertikaler V-Stellung angeordnet. Jeweils die beiden Einlassventile 37 liegen parallel zueinander, entsprechend einem V-Schenkel, der von der Ebene der beiden Einlassventile 37 bestimmt ist und - zum Schaftende der Einlassventile 37 hin gesehen-eine Aufwärtsneigung von ca. 37° aufweist. Der von den Auslassventilen 38 bestimmte V-Schenkel weist dagegen eine entsprechende Abwärtsneigung von ca. 15° auf. Die Nockenwellen liegen jeweils in einer winkelhalbierenden Lage innerhalb der ca. 52°-V-Stellung der Ventile 37 und 38.The valves 37 and 38 are arranged in the vertical V position. In each case, the two inlet valves 37 lie parallel to one another, corresponding to a V-leg, which is determined by the plane of the two inlet valves 37 and, as viewed towards the end of the inlet valve 37, has an upward inclination of approximately 37 °. The V-leg determined by the outlet valves 38, on the other hand, has a corresponding downward inclination of approximately 15 °. The camshafts are each in an angle bisecting position within the approx. 52 ° V position of valves 37 and 38.

Die Kipphebel 39 für den Antrieb jeweils eines Ventiles 37 bzw. 38 sind auf Lagerachsen 40 drehbeweglich angeordnet. Deren Drehlagerabschnitte 41 sind zu deren fest einspannbaren Achszapfen 42 für die Ventilspiel-Einstellung exzentrisch angeordnet (Fig. 2 und 5). Deren Achszapfen 42 sind in mittels Schrauben 43 verklemmbaren Lagerstühlen 44 des Zylinderkopfes 33 verdrehfest einspannbar. Für den Ventilspiel-Einstellvorgang ist den Lagerachsen 40 an jeweils einem zugänglichen Stirnende ein - aus der Zeichnung nicht ersichtliches - Schlüsselprofil angeformt. Ein Innenprofil wird dabei bevorzugt, weil es keinen Platzbedarf hat und als Materialausnehmung Gewicht spart. Die Ventilsteuerung weist damit insgesamt einen geringen Raumbedarf und Bauaufwand auf und enthält keine bewegten zusätzlichen Einzelteile für die Ventilspiel-Einstellung.The rocker arms 39 for driving a valve 37 or 38 are rotatably arranged on bearing axes 40. Their pivot bearing sections 41 are arranged eccentrically to their firmly clamped axle journals 42 for the valve clearance adjustment (FIGS. 2 and 5). Their axle journals 42 can be clamped non-rotatably in bearing seats 44 of the cylinder head 33 which can be clamped by means of screws 43. For the valve lash adjustment process, the bearing axles 40 have a key profile formed on an accessible front end, which cannot be seen in the drawing. An inner profile is preferred because it does not require space and saves weight as a material recess. The valve control thus requires little space and construction and does not contain any additional moving parts for the valve clearance adjustment.

Aus der oben beschriebenen V-Stellung der Ventile 37 und 38 ergibt sich in Verbindung mit der Anordnung jeweils der beiden Einlassventile 37 bzw. deren Ventilteller 37' in einem freien Abstand und der Anordnung einer Zündkerze 45 in diesem Abstand eine vorteilhafte Gestaltung des Brennraumes 46 (Fig. 2 und 4). Die Ventilteller 37' und 38' der Ein- 37 bzw. der Auslassventile 38 liegen nahezu tangierend eng an der zugehörigen Kreis-Kontur 32' des zugehörigen Zylinders 32 sowie in relativ engem Abstand zwischen dem Ventilteller 37' und jeweils einem Ventilteller 38'. Die Ventilteller 38' übergreifen dabei die horizontale Mittellinie 32" der Kreis-Kontur 32'. Die Funkenstrecke der Zündkerze 45 liegt zentrisch zwischen den Ventilen 37 und 38 im Brennraum 46. Im oberen Bereich des Brennraumes 46 lässt sich eine grosse Quetschfläche 47 ausbilden, die im Zusammenwirken mit einem flachen Bodenabschnitt eines Kolbens 48 einen Quetschspalt mit günstigem Einfluss auf den Verbrennungsvorgang ermöglicht. Die Zündkerze 45 ist in einer steileren Neigung als die Einlassventile 37 in der Vertikalebene 49 gemeinsam mit dem Auslassventil 38 angeordnet. Der Einbau-Raumbedarf der Zündkerze kommt dadurch nicht zwischen dem Raumbedarf der Ventilfedern 50 der Einlassventile 37 zur Geltung. Darüber hinaus weisen die Zündkerzen und deren elektrische Anschlüsse dadurch eine beson.- ders günstige Zugänglichkeit für die Wartung auf.From the V position of the valves 37 and 38 described above, in connection with the arrangement of the two inlet valves 37 or their valve plates 37 'at a free distance and the arrangement of a spark plug 45 at this distance, an advantageous design of the combustion chamber 46 ( 2 and 4). The valve plates 37 'and 38' of the inlet 37 and the outlet valves 38 are almost tangentially close to the associated circular contour 32 'of the associated cylinder 32 and at a relatively close distance between the valve plate 37' and each valve plate 38 '. The valve plate 38 'overlap the horizontal center line 32 "of the circular contour 32'. The spark gap of the spark plug 45 is located centrally between the valves 37 and 38 in the combustion chamber 46. In the upper region of the combustion chamber 46, a large squeeze area 47 can be formed enables a pinch gap with a favorable influence on the combustion process in cooperation with a flat bottom portion of a piston 48. The spark plug 45 is arranged at a steeper inclination than the inlet valves 37 in the vertical plane 49 together with the outlet valve 38. The installation space requirement of the spark plug comes as a result not between the space requirements of the valve springs 50 of the inlet valves 37. In addition, the spark plugs and their electrical connections are particularly conveniently accessible for maintenance.

Für die Fahrtwind-Luftkühlung der Zylinderköpfe 33 ist parallel zur Nockenwelle 14 im V-Raum der Ventile 37 und 38 ein - in Fahrtrichtung gesehen - offener horizontaler Kühlluftkanal 51 ausgebildet. Dieser mündet an seinem zur Fahrtrichtung entgegengesetzten Ende in einem vertikalen Abströmschacht 52, der vor dem Tunnel 36 des Kettentriebes 13 angeordnet und nach oben und unten offen ist. Eine hochwirksame Kühlung der Zylinderköpfe 33 wird dadurch ohne zusätzlichen Raumbedarf und Bauaufwand gewährleistet.For the airstream air cooling of the cylinder heads 33, parallel to the camshaft 14 in the V space of the valves 37 and 38, an open horizontal cooling air duct 51 is formed, as seen in the direction of travel. This ends at its end opposite to the direction of travel in a vertical outflow shaft 52 which is arranged in front of the tunnel 36 of the chain drive 13 and is open at the top and bottom. A highly effective cooling of the cylinder heads 33 is ensured without additional space and construction costs.

Eine günstige raumsparende Anordnung ergibt sich aus der oben beschriebenen Ventilanordnung auch für die Saugstutzen 28' mit den Vergasern 29 und für die Abgasleitungen 53. Während die Sauganlage an der Motor-Oberseite sich raumsparend eng an den Rahmen-Blechhohlkörper 23 anlehnt und dadurch eine geringe Breite aufweist, steht für eine Führung der Abgasleitungen 53 mit relativ grossen strömungs-widerstandsarmen Radien ausreichend Raum zur Verfügung, ohne die Boden - und die Schräglagen- Freiheit für den Motorrad-Fahrbetrieb zu beeinträchtigen.A favorable space-saving arrangement results from the valve arrangement described above also for the intake manifold 28 'with the carburetors 29 and for the exhaust pipes 53. While the suction system on the top of the engine rests closely on the frame sheet metal hollow body 23 in a space-saving manner and therefore has a small width there is sufficient space available for routing the exhaust pipes 53 with relatively large, low flow resistance radii, without impairing the ground - and the inclined freedom for motorcycle riding.

Der Gesamtaufbau des erfindungsgemässen Zweizylinder-Viertakt-Boxermotors ergibt vor allem für die Verwendung in Motorrädern eine Summierung einander gegenseitig ergänzender Vorteile hinsichtlich hoher Leistung, wirksamer Kühlung, guten Laufeigenschaften, geringem Gewicht und Bauaufwand, geringem Raumbedarf und ansprechender äusserer Form. Ein Grossteil dieser Vorteile kommt jedoch bei stationärer und/oder gekapselter Anwendung mit Gebläseluft- oder Flüssigkeits-Kühlung ebenfalls zur Geltung.

Figure imgb0001
Figure imgb0002
 The overall structure of the two-cylinder, four-stroke boxer engine according to the invention results, especially for use in motorcycles, in a summation of mutually complementary advantages with regard to high performance, effective cooling, good running properties, low weight and construction expenditure, small space requirement and appealing external shape. However, most of these advantages also come into play in stationary and / or encapsulated applications with forced air or liquid cooling.
Figure imgb0001
Figure imgb0002

Claims (13)

1. A two-cylinder four-stroke Boxer engine, especially an engine for a motor cycle which is cooled by the oncoming air-flow, comprising:
- for each cylinder (32), an overhead cam-shaft (14) which is arranged horizontally and parallel to the crank-shaft (3) and has a 1:2 reduction with respect to the crank-shaft (3);
- cam-shafts being each driven, through a roughly 1 : ratio chain-drive or belt-drive (13), by an intermediate shaft (4) which is reduced approximately 1:2 relatively to the crank-shaft speed and is arranged parallel to the crank-shaft (3) ;
- chain-drives or belt-drives (13) lying to the rear of the cylinders (32) in the direction of travel, and
- valves (37 and 38) actuated by rockers (39), characterized by the arrangement of:
- the intermediate shaft (4) below the crank-shaft (3);
- the drive for the intermediate shaft (4) at that end of the crank-shaft (3) that leads in the direction of travel;
- a pump wheel (12') of a lubricating-oil pump (12) below the crank-shaft and on the intermediate shaft (4);
- the chain-drives or belt-drives (13) in thetunnel (36) of the cylinders (32) and cylinder heads (33);
- the valves (37 and 38) in a V position as well as in planes vertical to the cam-shaft (14) which lies in a V-shaped space defined by the valves (37 and 38), and
- the suction and exhaust pipes (28'; 53) so that they extend respectively towards and away from the cylinder heads (33) substantially vertically in an upward and downward direction respectively.
2. A Boxer engine according to Claim 1, characterized in that the valves (37 and 38) are each turned in their vertical planes through such an angle, with respect to the horizontal to the V position, in that the outlet valves (38) are inclined downwards, at an angle of approximately 0 to 20°, and the inlet valves (37) are inclined upwards, at an angle of approximately 30 to 50°, to the horizontal of the plane concerned, said inclinations being as seen in the direction from the valve disc to the end of the valve stem.
3. A Boxer engine according to one of Claims 1 or 2, characterized in that, for each cylinder (32), two inlet valves (37) are arranged parallel to and alongside each other in similarly spaced vertical planes and one on each side of the vertical plane (49) of the outlet valve (38).
4. A Boxer engine according to Claim 3, characterized in that:
- the inlet valves (37) each have a gap at their valve discs (37');
- there is arranged in this gap a threaded bore for an ignition plug (45), which bore lies in the vertical plane (49) of the outlet valve (38) and does not intersect the valve-seat rings of the inlet valves (37), and
- the valve discs (37') of the inlet valves (37), in their closed position, are roughly tangential to or slightly overlapping the horizontal centre line (32") of the circular contour (32') of the associated cylinder (32) and are almost tangential to the circular contour (32') of the said cylinder (32).
5. A Boxer engine according to one of Claims 1 to 4, characterized in that:
- the bearing spindles (40) of the rockers (39) each have a rotary bearing portion (41) for the rocker (39), which portion (41 ) is eccentric in the cylinder head (33) with regard to their firmly clampable pivots (42);
- at least one firmly clampable pivot (42) has a clip device for securing the bearing spindle (40) in the rotary position, and
- a key cross-section is formed integrally with each bearing spindle (40) at at least one end face.
6. A Boxer engine according to one of Claims 1 to 5, with cooling-air guides on the cylinder head for cooling by the oncoming air-flow, characterized in that:
- a cooling air-duct (51) is arranged parallel to the cam-shaft (14) in the V-shaped space between the valves (37 and 38);
- said duct has an inflow orifice open in the direction of travel, and
- it discharges into an upwardly and/or downwardly vertically extending outflow passage (52) at the opposite end and in front of the tunnel (36) for the chain-drive or belt-drive (13).
7. A Boxer engine according to one of Claims 1 to 6, characterized in that:
- the crank-case (2) is divided in the vertical middle plane (I-I);
- the crank-shaft (3) and the intermediate shaft
(4) are arranged in the middle plane (I-I);
- a main bearing (10) is arranged at each side of immediately adjacent throws (3') of the crank-shaft (3), and
- an equalizing mass (11) is integrally formed immediately outside each of the two main bearings (10) and within shaft seals (10') for the crank-shaft (3) which are immediately adjacent the main bearings at side thereof.
8. A Boxer engine according to Claim 7, characterized in that the equalizing masses (11) take the form of narrow discs and are arranged in correspondingly narrow annular spaces (2') in the crank-case (2) between the main bearings (10) and the shaft seals (10').
9. A Boxer engine according to one of Claims 1 to 8, characterized in that:
- a peripheral fixing flange (20), with a number of fixing rings (21) and/or threaded bores for securing or receiving the fixing screws (22) of a sheet-metal hollow frame member (23), is formed integrally with the crank-case (2) on its upper face, and
- an opening (24) for removing air from the crank-case discharges within the top face framed by the fixing flange (20).
10. A Boxer engine according to one of Claims 1 to 9, with a substantially smooth-faced end-wall cover (18) for the crank-case (2), which cover closes off the adjacent equipment (generator 6) and/or the drive for the intermediate shaft (4), characterized in that an opening for fitting an oil filter (15) arranged longitudinally in the crank-case (2) is provided in the wall of the crank-case (2) that is closed off by the end-wall cover (18), which opening has a removable cover (17) comprising integrally formed connecting ducts (17') communicating with oil-ducts in the crank-case (2).
11. A Boxer engine according to Claim 4, characterized in that the longitudinal axis of the ignition plug (45) forms, with the axis of the cylinder, a greater angle - approximately 45 to 75° - than does the plane defined by the inlet valves (37).
EP82105324A 1981-06-26 1982-06-18 Two-cylinder four-stroke boxer engine, particularly for a motor cyle, cooled by the oncoming air flux Expired EP0068336B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE8383112438T DE3273260D1 (en) 1981-06-26 1982-06-18 Cylinder head for a four-stroke internal-combustion engine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19813125077 DE3125077A1 (en) 1981-06-26 1981-06-26 TWO-CYLINDER FOUR-STOCK BOXER ENGINE, ESPECIALLY DRIVE WIND AIR-COOLED FOR MOTORCYCLES
DE3125077 1981-06-26

Related Child Applications (1)

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EP83112438.3 Division-Into 1983-12-10

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EP0068336A1 EP0068336A1 (en) 1983-01-05
EP0068336B1 true EP0068336B1 (en) 1985-02-06

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EP83112438A Expired EP0113450B1 (en) 1981-06-26 1982-06-18 Cylinder head for a four-stroke internal-combustion engine
EP82105324A Expired EP0068336B1 (en) 1981-06-26 1982-06-18 Two-cylinder four-stroke boxer engine, particularly for a motor cyle, cooled by the oncoming air flux

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EP (2) EP0113450B1 (en)
JP (1) JPS58501045A (en)
DE (3) DE3125077A1 (en)
WO (1) WO1983000188A1 (en)

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Publication number Priority date Publication date Assignee Title
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Also Published As

Publication number Publication date
JPS58501045A (en) 1983-06-30
EP0113450B1 (en) 1986-09-10
US4558676A (en) 1985-12-17
EP0068336A1 (en) 1983-01-05
WO1983000188A1 (en) 1983-01-20
EP0113450A1 (en) 1984-07-18
JPS6127569B2 (en) 1986-06-26
DE3262212D1 (en) 1985-03-21
DE3273260D1 (en) 1986-10-16
DE3125077A1 (en) 1983-01-13

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