Abstract: An improved design for the central power and suction unit of built-in vacuum cleaning systems, which improved design provides significant acoustic damping to substantially reduce the noise level generated from the central power and suction unit. The design further permits the canister of the central power and suction unit to rest on the floor. The motors of the central power unit are enclosed within an interior chamber which includes at its lower end a baffle supporting an acoustic damper such as acoustic foam and the interior chamber is vented through exhaust ports the tips of the armatures are separated from the remainder of the armatures and motors by the baffle and the tips of the armatures extend into another chamber which further includes a second acoustic damper within the chamber and further includes openings for permitting cooling air to enter the chamber. Through this design, the noise level generated from the motors is very substantially reduced while the motors are sufficiently cooled.

Abstract: In an air-cooled type cooling system for an engine working machine assembly in which a working machine such as a generator, a compressor and the like is adapted to be driven by an internal combustion engine, there are provided an air-cooled engine, a working machine and an exhaust muffler in a machine area as well as a centrifugal cooling fan in a fan room within a casing. An exhaust air outlet passage and an exhaust air conduction passage are provided in such a manner as to come out in parallel from the periphery of the fan area. Part of the cooling air sucked into the fan area after cooling the engine and the working machine in the machine area is adapted to be discharged directly outside the casing through the exhaust air outlet passage, and the remaining part thereof is adapted to be discharged outside the casing through the exhaust air conduction passage after cooling the exhaust muffler.

Abstract: The invention is directed to an exhaust gas muffler for a two-cycle engine, especially for a handheld portable tool, such as a chain saw. In exhaust gas mufflers equipped with a catalyzer, the formation of flame from the fuel-containing exhaust gases exiting from the muffler must be prevented. These exhaust gases are intensely overheated because of the exothermal process in the catalyzer. The muffler according to the invention includes a catalyzer which establishes a connection between separate component chambers of the muffler housing. The muffler can be mounted directly on the motor outlet.

Abstract: The invention relates to an exhaust gas muffler for a two-stroke engine of a portable handheld tool such as a chain saw. The exhaust gas muffler includes a catalyzer wherein high exhaust gas temperatures are developed because of the exothermal reaction which takes place therein. The catalyzer is located in the forward portion of a gas-tight hollow body mounted in the housing of the muffler. The hollow body has a tapered portion which extends out of the housing in the direction of the exhaust gas flow. In this way, the surface temperature of the muffler housing is reduced.

Abstract: The silencer according to the invention contains two chambers (10,11) separated by a partition wall (14) and includes also a guide plate (25) guiding cooling air from a fan (27) through a channel (26) in which recesses (23) from one chamber terminate. By means of an ejecting function, then being formed, exhaust gases are evacuated into the channel and mixed with the cooling air to a lower temperature.

Abstract: An exhaust gas system with a silencer for an internal combustion engine supercharged by a turbocharger includes a main line leading to the turbine of the turbocharger and a bypass line bypassing the turbine. The main line and the bypass line terminate in the silencer aligned to one another in such a manner that the exhaust gas flow of the main line exerts an ejector action on the exhaust gas flow of the bypass line.

Abstract: A muffler for work vehicle V-type internal combustion engines is disclosed, which is mounted in a horizontal sideway position, with its axis placed perpendicularly with the longitudinal vehicle axis, kept a proper distance from the chassis or vehicle body so that it is disposed in full exposure to the atmosphere for proper cooling. A pair of spaced inlet ports are provided in the muffler, at locations adjacent to opposite ends thereof for receiving the exhaust gases from the engine through a pair of parallely extending, parallel exhaust pipes directly interconnected between the combustion chambers of the two cylinders and the muffler inlet ports, without using the conventional intermediate flexible corrugated connectors.

Abstract: An improved muffler system for mounting within a restricted engine compartment such as the engine compartment of a small off-road vehicle including a muffler surrounded by a heat shield having a plurality of apertures formed therein for selectively cooling selected certain areas of the engine compartment in conjunction with a venturi which creates a flow of cooling air from outside the engine compartment, over the engine, into the apertures, between the heat shield and the muffler to a point where the exhaust gas and the initially cooler air are mixed and subsequently exited into the atmosphere.

Abstract: An aspirating muffler having a simplified venturi construction. The muffler includes a body having an inlet pipe connected to the exhaust system of an engine and having an outlet pipe. The upstream end of the outlet pipe is rolled inwardly to provide the end with a reduced cross sectional area which defines a venturi. An aspirating tube which is connected to an air cleaner pre-cleaner for the engine communicates with the venturi and flow of exhaust gas through the venturi end of the outlet pipe creates an aspirating action to draw solid particles from the pre-cleaner and discharge the particles through the outlet pipe to the atmosphere.

Abstract: A muffler for internal combustion engine houses a catalyst for exhaust gas purification and is provided with an exhaust gas inlet pipe through which exhaust gas from the engine is fed to the upstream side of the catalyst. The exhaust gas inlet pipe includes an inlet pipe section provided therein with a venturi section through which atmospheric air as secondary air is inducted into the exhaust gas inlet pipe. The inlet pipe section is extended in the direction of exhaust gas flow to form an extension pipe section which has a length of at least two times the inner diameter of the extension pipe section, thereby suppressing cutoff frequency at lower levels.

Abstract: This invention relates to a mounting arrangement (10) for resiliently connecting an exhaust stack (12) to an exhaust pipe (14) and a frame (18) which eliminates the problems of vibration, noise transfer, joint failure, high exhaust temperatures, complexity, and inability to quickly assemble and disassemble. The mounting arrangement (10) has first and second spaced apart elastomeric devices (60,80) for resiliently connecting the exhaust stack (12) to the frame (18), a support bracket (98) and an exhaust pipe (14). The first elastomeric device (60) supports an open end of the exhaust pipe (14) in the exhaust stack (12) and on the frame (18) and the second elastomeric device (80) engages the support bracket (98) and which retains the first elastomeric device (60) in contact with the frame (18). A passage arrangement (74) passes cooling air flow past the first elastomeric device to cool the first elastomeric device (60) and the exhaust stack (12).

Abstract: A muffler for an internal combustion engine comprises an air inlet passage in a casing of said muffler in a hollow surrounded by an inner wall of said casing and an outer wall of a porous sound absorber which is held in said casing.

Abstract: An exhaust assembly for a tractor having a pivotal or slidable engine hood that must be moved out of the way to permit an operator complete access into the engine compartment. The exhaust assembly includes a tubular housing positioned within the engine compartment below the top surface of the engine hood. The tubular housing has a cylindrically shaped inlet conduit adapted to be connected to the exhaust manifold of the tractor engine. Exhaust gases are forced vertically into the inlet conduit and then directed in a horizontal swirling fashion through the tubular housing by apertures and baffles along the length of the inlet conduit. The tubular housing further includes a cylindrically shaped outlet conduit having an open conical discharge end which is in close proximity to the lower end of an elongated exhaust tube that is attached to the engine hood.

Abstract: Film cooling apparatus adapted to be connected into a conduit carrying a hot exhaust gas. The apparatus comprises single walled contoured duct means connectible to said conduit and a center-body aerodynamically shaped and supported within said duct means so as to form therewith an annular channel of zero pressure gradient. Slot means are provided in the single walled contoured duct means and in the center-body to enable a flow of cooling air over exterior surfaces thereof to maintain said surfaces at an acceptably low temperature. A network of ducting carries the cooling air to the contoured duct means and interior of the center-body. The duct means and center-body are preferably of circular cross-section taken orthogonally of the overall flow direction. The center-body is an axisymmetric bulb having annular slots for directing the cooling air over the exterior of said bulb.

Abstract: An exhaust gas pressure reducer for an internal combustion engine which is comprised of a housing having means for attaching the housing to the end of the exhaust pipe. The housing has one or more venturi restrictions and is open at the ends for creating a draft across the end of the exhaust pipe through the venturi and out the opposite open end of the housing. The open exit of the housing reduces pressure at the exit to the venturi assisting drawing exhaust gases from the exhaust pipe.

Abstract: A muffler for a vehicle mounted on a hood of an engine compartment, comprising an outer cylindrical member having a plurality of openings formed in the lower side wall thereof, an inner cylindrical member mounted on the bottom wall of the outer cylindrical member, the inner cylindrical member being connected to an exhaust pipe and reduced in diameter at the upper side wall thereof, and an extension pipe connected to the upper end of the outer cylindrical member wherein the outer cylindrical member is mounted on the hood in such a manner that the approximately lower half thereof is positioned under the hood.

Abstract: A muffler system positioned within the engine housing of the vehicle such as a garden tractor, includes a muffler surrounded by an open ended tubular heat shield having a venturi tube on its outer end which receives and accelerates the exhaust gases to create a flow of cooling air through the engine housing and between the muffler and the tubular heat shield for extracting heat from both the engine housing and the muffler.

Abstract: The invention relates to an exhaust silencer for internal combustion engines, particularly for manually operated appliances, in which a reduction of the contact and exhaust gas temperatures in order to prevent fire risks on contact with easily flammable objects, particularly forest fires, during the putting into operation of the manually operated appliance and with the supply of a large quantity of fresh air compared with the quantity of exhaust gas in order to bring about a maximum cooling of the hottest gases and/or the outer walls, is achieved in that the wall of the exhaust silencer shell portion which bounds the cooling pipe on one side, following the final outlet hood facing the pipe output port for deflecting the exhaust gas has a negative angular variation with an angle of approximately 2.degree. to 8.degree. for forming a pure or fluidic logic element.

Abstract: A method of and a device for attenuating the noise radiated by a free-expion gas jet throughout the audible-frequency range as well as in the ultrasonic and infrasonic frequency ranges. Concomitantly with the complete and shock-free expansion of the gas into the atmosphere, the acoustic field of the jet is organized by the substantial diminution of the low-frequency tones by causing them to pass from the annular section of the jet to the narrow annular section of the nozzle slot. This is followed by sound-wave diffraction on emergence from the slot in the presence of a baffle, and by a wave reflection towards the sound-absorption lining of the device housing. The final noise results from an intensive ejection of ambient air by the primary gas which, leaving the nozzle slot, entrains the air by means of turbulence, the air entering through the annular channels of the case, reaching the outer orifices of the nozzle, and dividing into two flows, namely inside and outside the nozzle.

Abstract: A spark arrestor aspirating muffler for an internal combustion engine which comprises an outer body or housing having an exhaust gas inlet in one end and a gas outlet in the opposite end. Located immediately upstream of the outlet is a venturi and air is drawn into the throat of the venturi through an air inlet tube connected to a pre-cleaner for the engine. A baffle plate containing a series of louvered openings is positioned upstream of the venturi and the exhaust gases entering the gas inlet conduit are swirled outwardly as they pass through the louvered openings and are discharged through the venturi. The solid particles in the swirling exhaust gas are thrown outwardly and move along the inner surface of a tubular member which is secured to the downstream side of the baffle and are collected in a collection chamber.

Abstract: A system for diffusing exhaust gases and controlling and suppressing backfire in an industrial truck is disclosed. Exhaust gases from the truck engine are first passed through a spark arresting muffler to remove hot, solid particles from the gas stream. The gases are then routed to a diffuser which is mounted on the truck's overhead guard. The diffuser contains a venturi and an air intake manifold to mix outside air with the gas stream and complete the ignition of unburned backfire gases. The diffuser includes a transverse diffusion chamber for substantially containing and burning backfires therein and a series of thin exit pipes for dispersing the gases and quenching exiting flames produced by the backfires within the chamber.

Abstract: A method of and a device for attenuating the noise radiated by a free-expion gas jet throughout the audible-frequency range as well as in the ultrasonic and infrasonic frequency ranges. Concomitantly with the complete and shock-free expansion of the gas into the atmosphere, the acoustic field of the jet is organized by the substantial diminution of the low-frequency tones by causing them to pass from the annular section of the jet to the narrow annular section of the nozzle slot. This is followed by sound-wave diffraction on emergence from the slot in the presence of a baffle, and by a wave reflection towards the sound-absorption lining of the device housing. The final noise results from an intensive ejection of ambient air by the primary gas which, leving the nozzle slot, entrains the air by means of turbulence, the air entering through the annular channels of the case, reaching the outer orifices of the nozzle, and dividing into two flows, namely inside and outside the nozzle.

Abstract: A silencing and cooling system for engine exhausts. The system utilizes a silencer body having an axial passage containing barriers, deflectors, and guide vanes. Cooling air enters via an axial inlet at one end and mixes with exhaust gases entering the axial passage from a lateral opening in the body as they travel to the outlet at the other end of the axial passage.

Abstract: Zinc coated tubes are cleaned by means of steam, and the zinc residue -- steam mixture is blown into a nozzle which is heated, and discharged into a noise attenuation chamber; the latter discharges into an expansion chamber, which in turn discharges into a filter. The mixture is diluted in the attenuation chamber by air sucked in from the outside along a tortuous path.