Abstract: A seal for use on a noise-deadening shroud encasing an internal combustion engine, particularly the portion thereof which encases the muffler. A gap is formed between the outlet pipe for the muffler and the wall of the opening in the enclosure for the muffler. A seal is provided for this gap and includes a closure member which surrounds the exhaust outlet pipe with very little clearance therebetween.

Abstract: A hood (12) for an internal combustion engine compartment (C) has an air precleaner (10) and a muffler (11) mounted on the underside of the hood (12). The collar (26) connecting the precleaner (10) to the engine air intake (M1), and the pipe (36) from the exhaust manifold (M2) to the muffler (11) are both connected by means (26b, 37) which are releasable with the hood (12) in position, so the hood (12), precleaner (10) and muffler (11) constitute a removable module.

Abstract: An engine enclosure (10) has a noise suppression arrangement (15,15a,15b) mounted thereon including a plurality of acoustical energy absorbers (20,20a,20b) and sound reflectors (24,24a,24b) spaced from the absorbers to provide airflow passages (26,26a,26b) therebetween. The noise suppression arrangement (15,15a,15b) efficiently absorbs and reflects acoustical energy and exhibits a low space to sound absorption efficiency ratio in comparison to conventional noise suppression arrangements.

Abstract: An internal combustion engine surrounded, at least in part, by a sound insulating casing. The casing is closed to the atmosphere with the exception of an inlet opening for receiving air for combustion in the engine. An air filter is coupled to the inlet opening for filtering the air passing through this opening into the interior of the casing.

Abstract: A reed type valve is operatively secured on the outer surface of the casing of an engine air filter assembly to supply the exhaust system of an engine with secondary air. The reed valve is fluidly connected to an air induction passage formed interior of the casing of the air filter assembly. A resonance chamber is also formed interior of the casing and communicated through a communication passage with the air induction passage so as to attenuate a relatively low frequency component of exhaust noise transmitted through the reed valve. The air induction passage, resonance chamber and communication passage are formed as follows: ##EQU1## where, S.sub.o (cm.sup.2)=the cross-sectional area of the air induction passageS(cm.sup.2)=the cross-sectional area of the communication passagel(cm)=the length of the communication passageV(cm.sup.3)=the volume of the resonance chamberM=the number of the engine cylinders of the engine.

Abstract: In an internal combustion engine comprising a crankshaft (7) and crankshaft main bearings (6), an engine unit support (1) which supports the crankshaft main bearings, and a cylinderhead (3) mounted on the engine unit support (1), which are engine parts directly affected by body resonance and sound vibration, at least one vibration absorbing and power transmitting element (15) located between the engine parts directly affected by sound vibration and the crankcase (8), a sealing element (21) located in a joint between a engine unit support (1) and the crankcase (8) which seals an encapsulated upper dry engine region oil-tightly against a lower oil-wetted engine region (22), an elastic filling element (19) bridging at least a part of the joint being inserted into the joint before the mounting of the sealing element (21) and supporting the latter, whereby the sealing element (21) comprises a viscous material forming an adhesive compound with metal which is resilient after curing.

Abstract: In a reciprocating internal-combustion engine, a power unit comprises cylinders 1, cylinder heads 2, pistons, connecting rods, a crankshaft and crankshaft bearings. Soundproofing supporting members mount the ends of the power unit in an outer pan 7 which is connected to a flywheel housing 8. Soundproofing supporting members 12, 12a, 13 are coaxial with the crankshaft and center the power unit and hold it against substantial axial movement in the outer pan. An oil seal 14 is fitted between the power block and the top rim of the outer pan.

Abstract: A narrow profile power handle uniquely adapted for use as a flexible line trimmer having improved handling and safety features is disclosed. The power handle is also equipped with a quick connect and disconnect coupling and is useful for driving attachments to produce hand held rotary implements and tools such as brush cutters, edgers, cultivators, drills, etc., hand held reciprocating implements and tools such as hedge clippers, saws, etc., as well as portable water pumps, air compressors, generators, etc.The crankshaft of a two-stroke internal combustion engine is disposed along the longitudinal axis of a narrow profile housing which includes a rear handle having a hand grip portion disposed above and projecting rearwardly parallel to the axis of the housing. The cylinder extends upwardly from the crankcase, the carburetor is disposed below the crankcase, the flywheel, ignition system and starter to the rear, and the gas tank is disposed below the rear handle.

Abstract: A housing for an internal combustion engine of the type used with portable chain saws having a cavity therein for a fuel supply and another cavity for lubricating oil. The engine housing is composed of at least an upper and a lower portion which are joined along a substantially horizontal dividing plane which is substantially parallel to the bottom plate of the lower portion of the engine housing. The dividing plane intersects the crankshaft casing of the engine whereby two separate closed cavities are formed for separately storing fuel and lubricating oil for said chain saw.

Abstract: An internal combustion engine comprising a flywheel mounted on a crankshaft and an aggregate housing which surrounds the flywheel and is mounted on the crank housing by vibration-damping buffer elements extending tangentially of the flywheel, which aggregate housing rotatably supports a drive shaft for an aggregate driven by the engine.

Abstract: A sound absorbing and attenuating panel is located at one end of an engine compartment for silencing the noise generated by an engine cooling fan located in the compartment. The panel includes a first set of laterally spaced, vertically extending silencing units comprising sound absorbing material encased in perforated containers and a second set of silencing units located one each between each of the first set of units and each comprising a container defining a combination of a pair of resonator chambers separated by a cavity filled with sound absorbing material.

Abstract: An internal combustion engine has a plurality of air intake conduits, air intake nipples, an air filter operatively coupled to the air intake conduits, a sound insulating capsule covering the engine, and at least one inlet opening in the capsule for admitting intake air. The intake conduits are integrated in the capsule and are directly connected to the respective air intake nipples.

Abstract: An internal combustion engine for an automobile is encased in a sound-insulating casing and is mounted on a frame of the automobile via sound-proofing suspensions. The wall of the casing extends around the suspensions, at which point the casing is supported on the frame by means of casing wall portions. These casing wall portions are acoustically insulated from the remainder of the casing wall by sound-insulating intermediate layers, e.g. by flat, elastic, annular sealing rings.

Abstract: A noise-proof and air-cooled enclosure system for an engine comprising a radiator compartment, a generally enclosed engine compartment separated from said radiator compartment by a partition wall, said radiator compartment being arranged sideways with respect to said engine compartment, and an ejector utilizing the flow of gases from an engine exhaust pipe for creating a relatively low pressure within an air outlet from said engine compartment to draw ambient cooling air through said radiator compartment into said engine compartment around said engine and out of said air outlet.

Abstract: An internal combustion engine with a sound-insulating enclosure and with a radiator arranged outside of the enclosure having a cooling fan and a cooling air box which has a discharge outlet outside of the enclosure; at least one cooling air line is thereby connected with the cooling air box which extends into the enclosure and whose discharge opening or openings is or are directed at least against one part or aggregate to be cooled.

Abstract: The carburetor of a motorcycle engine is fastened to an engine cylinder by a thin resilient hose connecting the fuel mixture outlet port of the carburetor to the intake port of the cylinder. The carburetor is fastened to the casing of the associated air cleaner much more rigidly than it is fastened to the cylinder. The fastening connection between the carburetor and the air cleaner casing is provided by a tubular member having a wider orifice fastened to said casing, a narrower orifice fastened to the carburetor, and a shoulder portion connecting the orifices and of greater wall thickness near the float chamber in the carburetor than elsewhere.

Abstract: An internal combustion engine includes an engine block and an oil pan sealingly secured to one another along substantially horizontally extending mounting faces to constitute a unit and a sound-insulating capsule shrouding the engine block and having a lower terminal zone. A sound dampening mounting arrangement is provided for attaching the lower terminal zone of the capsule to the unit at the height level of the mounting faces.

Abstract: To compensate for positional variations during assembly or in use between an engine body or crankcase and a sound-proofing shell enclosing the same, use is made of interposed spring arrangements including a load-setting means.

Abstract: There is provided a resilient connection between an engine and a transmission housing, of a vehicle of the open frame type, for dampening engine generated noise which is transmitted to the frame via the transmission housing. The resilient connection comprises rubber rings or cups on metallic spacer bushings compressed between the engine and housing. There is also an axially telescopic drive shaft from the engine to the transmission which accepts limited angular movement between the engine and housing in the plane of the resilient connection.

Abstract: An internal combustion engine with a sound-reducing encapsulation, wherein at least the hottest parts of the exhaust system of the engine are located outside of the engine encapsulation and within a special exhaust pipe casing. At the upper side of the exhaust pipe casing an air outlet opening is provided through which the air heated by the exhaust system parts can emerge to the surroundings without getting into the encapsulation. The air outlet opening is lined with sound-absorbing material. The free sectional area of the air outlet opening preferably may be variable by flap means and in dependency of an engine operation parameter. The flap means can be operated by a hydraulic cylinder connected to the lubricating system of the engine.

Abstract: A low-noise-level combustion engine comprises an engine unit support with auxiliary units rigidly connected thereto, a crankcase and a flywheel case. The engine unit support, as an engine part directly affected by sound vibration, is connected to the crankcase by at least three resonance-absorbing elements which provide power transmission from the engine unit support to the crankcase. The engine comprises further a sealing element located between the engine unit support and the crankcase, which divides the engine into a lower oil-wetted engine region and an upper dry engine region which is oil-tightly sealed against the lower engine region. The sealing element surrounds the engine, the engine unit support, and is attached to the engine unit support and to the crankcase. It has no supporting function and is highly resilient.

Abstract: An internal combustion engine having a noise-suppressing encapsulation, a cooling air blower to ventilate the encapsulation, at least one cooling air inlet opening and at least one cooling air outlet opening arranged in the encapsulation, and an exhaust pipe connected to the engine by means of at least one body-resonance-absorbing compensator located at least partially within the encapsulation. The compensator penetrates the encapsulation without touching it and in the region of penetration is arranged at least one plate-like absorption silencer substantially within a plane perpendicular to the compensator axis.

Abstract: An internal combustion engine having a noise suppressing encapsulation, said encapsulation being ventilated by a blower and cooling air ducts being formed within the encapsulation by means of partitions, one of said cooling air ducts comprising all fuel and oil leading engine parts and the other cooling air duct being imperviously divided from the first one comprising the parts of the exhaust system.

Abstract: A ventilation system for an encapsulated internal combustion engine providing a reduction in short-circuit air flow from the pressure side to the suction side of the ventilation radial fan.

Abstract: A fork-lift truck having a chassis provided with a counterweight to balance the weight of a load carried by the mast and fork of the vehicle and an internal-combustion engine for propelling the vehicle, e.g. via a hydrostatic transmission, has the passages for the flow of cooling air to and from the engine formed directly in the counterweight and provided with flow-deflecting bends to serve as noise dampers. The noise at least emitted from the intake duct is thus partially damped by absorption of acoustic energy in the relatively massive counterweight.

Abstract: An internal combustion engine has an engine block, an oil pan and a sound insulating capsule shrouding the engine block. The engine block and the oil pan have circumferential mounting faces oriented towards one another. A mounting arrangement includes a sound dampening intermediate layer situated between the mounting faces for a noise-dampened connection of the oil pan with the engine block and with a lower terminal zone of the capsule. The oil pan is held by the lower terminal zone of the capsule and the capsule is supported by a component other than the internal combustion engine. The intermediate layer is constituted by a gasket which has at least one fold to take up relative motions between the engine block and the oil pan during operation of the internal combustion engine.

Abstract: A sound proof encapsulated engine, particularly an internal combustion engine, comprising a fan and an intermediate support for the fan, the fan being driven by an elastic element and mounted on the engine case with the aid of the intermediate support by means of a number of bearing faces, the fan bearing housing and the fan drive being accommodated within the encapsulation, and between the engine case and each of the bearing faces being provided an intermediate support having n elastic and body-transmitted sound-absorbing element.

Abstract: An internal combustion engine comprises an engine unit support and a crankcase which parts are connected by a resonance-absorbing element. The engine parts located above the resonance-absorbing element are encased by a noise-suppressing encapsulation. The exhaust pipe and the inlet pipe penetrate the encapsulation without touching it and are connected to the cylinderhead by vibration-insulating couplings. Supporting arms are provided which support the exhaust and the inlet pipes. The supporting arms are secured to the crankcase which is freed from body resonance due to the resonance-absorbing element. The supporting arms take over all holding and vibration forces so that the vibration-insulating couplings may be designed very soft in the sense of optimal vibration insulation.

Abstract: A device for the measurement of the engine oil level in sound proof encapsulated internal combustion engines by means of an oil dipstick.

Abstract: A motor vehicle has an engine equipped with an oil sump which is secured in a body-sound-insulated manner to the engine block, and a fan-cooled water radiator, a frame-mounted elastic membrane being provided between the oil sump and the vehicle body components so that the membrane completely encircles the oil sump at its upper edge and provides an acoustic separation between the spaces respectively situated above and below the oil sump, the upper space comprising a sound suppressing encapsulation which is closed relative to the vehicle interior by appropriate wall panels, partitions and sealing sections provided in the vehicle body. The outflow of hot cooling air from the radiator completely by-passes the encapsulation, the sealed upper space of the encapsulation being cooled by the forced draught of a further fan, and sound absorbing silencers being provided at inlet and outlet openings for the cooling air in the encapsulation.

Abstract: An internal combustion engine having a sound-deadening shroud surrounding the engine block and connected to latter with the interposition of anti-vibration means. An exhaust plant through which combustion gases are connected is arranged external of the shroud and connected to the engine block. A separate enclosure is secured to the shroud and encloses the exhaust plant leaving a small air gap on all sides between the exhaust plant and the enclosure with only the exhaust pipe of the exhaust plant projecting from the enclosure through an opening.

Abstract: The present invention is related to a casting for muffling sound conducted through solids and reducing noise in internal combustion engines and to a method for production of the casting.

Abstract: A motor vehicle with an internal combustion engine supported on two longitudinal subframe beams of the vehicle and provided with a noise-suppressing engine encapsulation consisting of a hood supported by the vehicle frame and including substantially perpendicular longitudinal and transverse walls, and a movable cover part on the upper rims of the walls, a front end wall situated in front of the engine reaching from the bottom rims of the beams to above a passage opening for the engines cooling water, a rear end wall arranged behind the gearbox extending downwardly from the top edges of the beams, and a middle transverse wall extending behind the engine from the top edges of the beams over an air intake pipe and exhaust pipes, two longitudinal side walls extending from the front end wall to the middle transverse wall and an oil sump cover part provided underneath the beams for completing an allround encapsulation assembly.

Abstract: A sound absorbing arrangement for an internal combustion engine having sound absorbing panels encasing the internal combustion engine. Cooling air is drawn in through openings in the paneling to subject the external surface of the engine body to the cooling air. The panels are lined with a sound absorbing material. The sound emitted from the air filter is muffled by arranging the air intake thereto so that it passes first in and around the engine and then through an intake pipe from the chamber defined by the paneling into the air filter.

Abstract: A sound abatement device for an internal combustion engine including a contoured shell resiliently mounted to reduce sound transmission through the shell mounting. The shell is formed of plastic filled with powdered metal to reduce transmission of air transmitted sound from the engine through the shell.

Abstract: There is provided a resilient connection between an engine and a transmission housing, of a vehicle of the open frame type, for dampening engine generated noise which is transmitted to the frame via the transmission housing. The resilient connection comprises rubber rings or cups on metallic spacer bushings compressed between the engine and housing. There is also an axially telescopic drive shaft from the engine to the transmission which accepts limited angular movement between the engine and housing in the plane of the resilient connection.

Abstract: An engine has a swingable hood with an exhaust stack and air inlet drain cap mounted thereon for swinging therewith which are operative with a muffler outlet and an air cleaner inlet, respectively, when the hood is in an operative position enclosing the engine of a vehicle on which the hood is mounted. A deflector is located between the muffler and air cleaner and oriented to deflect cooling air for the muffler to exhaust vents and the stack which stack forms an annulus around the muffler outlet to give a jet pump type action to enhance the draft for the stack which entrains the effluent from the muffler outlet while at the same time providing a radiant and convective heat shield for the air cleaner.

Abstract: An internal combustion engine with auxiliary machines driven by a V-belt and pulley from the engine the engine and the pulley being enclosed by a sound suppressing encapsulation, the auxiliary machines being mounted externally of the encapsulation, the V-belt extending at least partly through a sound absorbing funnel-shaped leadthrough to the pulley, the funnel-shaped leadthrough providing a silencer unit and a passageway for the intake of cooling air into the encapsulation.

Abstract: A cover is provided for an engine which has first and second spaced-apart portions and an air cleaner. The cover has a middle portion, first and second opposed side portions, and first and second opposed end portions. The side and end portions are connected to the engine and form a chamber defined by the engine portions and the cover. The air cleaner is mounted on the middle portion of the cover.

Abstract: A bonnet structure for generator comprising a main wall enclosing the generator and an engine for driving the generator, a partition wall for dividing the bonnet into two chambers, each chamber containing the engine and the generator, respectively, and the cover wall provided on said main wall wherein a rotor-fan of the generator is positioned within the chamber containing the engine.

Abstract: A noise control enclosure comprises an assembly of a plurality of panels each having a structural framework on which a sound deadening sheet material is affixed. The structural framework is formed of frame members which have mounting flanges which are disposed about the periphery of the structural framework of each panel. The sound deadening sheet is permanently affixed thereto, for example by a suitable adhesive. Individual panels are removably connected to each other to form the enclosure by fastening means such as self-tapping screws. The sheet material is interposed between abutting frame members of adjacent panels. Peripheral edges of the sheets mounted on the framework or strips of similar material extend between abutting frame members of the structural framework to provide acoustic sealing between panels. The individual panel construction permits on site assembly and disassembly.

Abstract: An air sucking device for engines wherein the suction pipe, carburetor, and air cleaner are integrally connected together. The carburetor and suction pipe are housed within a covering so that the device affords protection and a favorable appearance for the respective components. The suction passageway is of a sufficient length to make operation of the engine more efficient.

Abstract: A motor vehicle with a soundproof encapsulated engine-gearbox unit, wherein the two subframe beams of the vehicle and/or further parts of the vehicle frame and the vehicle body form supplementary integral members of an allround fully closed soundproof encapsulation of the engine-gearbox unit.

Abstract: A construction for V type internal combustion engines having a pair of banks arranged in a V shaped form. An intake duct is composed of a metal sheet bottom portion and a metal sheet body formed with an intake passage both of which are coupled to each other. Partition walls are also provided on the front and rear end portions of the engine and coupled with the bottom portion of the intake duct so as to form a soundproofing chamber between the pair of banks.

Abstract: Low-noise-level internal combustion engine with an engine unit support and a cylinder head mounted thereon, auxiliary units rigidly connected to the engine unit support and the cylinder head, an engine case surrounding the engine unit support and connected to same by at least one resonance absorbing member.

Abstract: An internal combustion engine has an enclosure mounted therearound comprising an outer enclosure having a horizontally disposed hood positioned over a top of the engine and a pair of vertically disposed sidewalls positioned on either side thereof. An inner enclosure, disposed within the outer enclosure, comprises a horizontally disposed upper wall which is spaced vertically between the top of the engine and the hood to define first and second airflow passages therewith, the second airflow passage being further defined in part by the sidewalls. The inner enclosure further comprises a vertically disposed forward wall positioned adjacent to the front of the engine. An airflow guide means is secured internally on each of the sidewalls to define a passage therebetween which communicates with the second airflow passage defined about the engine.

Abstract: Engine noises directed to the bottom portion of an engine compartment are reflected from the surface of an under-cover partly closing the engine compartment bottom opening and thereafter absorbed by sound-absorbent material attached to the inner surface of the hood of the engine compartment.

Abstract: A noise reducing material especially suitable for attaching to internal combustion engine casing parts and comprising (a) a layer of a metal such as lead combining a high density with a low shear modulus, bonded to (b) a layer of a pliant thermoplastics matrix reinforced with fibrous material. Layer (b) is preferably asbestos fiber-reinforced bitumen and the laminate preferably comprises a layer of lead between two layers of the reinforced thermoplastics material.

Abstract: An internal combustion engine having a soundproof casing aerated by a blower and divided by at least one partition wall into two cooling air ducts tightly separated from each other, one of the ducts containing all fuel carrying members of the engine, the second duct containing the members of the exhaust system of the engine, the cooling air ducts being admitted by two partial cooling air flows.