A hedge trimmer has at least one cutting blade and an internal combustion engine operatively connected to the at least one cutting blade so as to drive the at least one cutting blade reciprocatingly. The internal combustion engine has an exhaust gas muffler with an outlet for discharging exhaust gases from the exhaust gas muffler. A multi-part exhaust gas pipe is connected seal-tightly to the outlet of the exhaust gas muffler and connects the outlet of the exhaust gas muffler to an outlet opening where the exhaust gases exit from the hedge trimmer. The multi-part exhaust gas pipe has a plurality of pipe sections, including at least a first pipe section and a second pipe section, wherein the second pipe section is embodied separate from the first pipe section. At least one of the plurality of pipe sections is made of plastic material.

A muffling structure for a pneumatic tool is provided and disposed in an exhaust pipe of the pneumatic tool. The muffling structure includes: an outer cylinder separated from the exhaust pipe by an outer gap-channel and defined with inlet and outlet ends, with the outlet end having a stop portion; an inner cylinder defined with an upstream end and a downstream end, the downstream end passing the inlet end to protrude into the outer cylinder and abut against the stop portion. The upstream end protrudes from the inlet end and has a baffling plate. The baffling plate has an area not less than the inlet end and separates from the exhaust pipe by a gap. An inner gap-channel is formed between the inner and outer cylinders. A communication opening whereby the outer and inner gap-channels are in communication is formed between the baffling plate and the inlet end.

A muffler for an engine assembly is disclosed. This muffler is arcuately-shaped and may be configured so as to not protrude beyond an outermost perimeter of an engine assembly that uses this muffler. The muffler may include a lower chamber, an intermediate chamber, and an upper chamber that are disposed in a common stack. Exhaust inlet and outlet ports to the muffler may be located at a common end of the muffler body. The exhaust inlet port may lead into the lower chamber. Multiple exhaust outlet ports out of the upper chamber may be utilized to allow the muffler to be used with different vehicle configurations, for instance to direct exhaust out of the muffler in different directions.

A muffler for single-cylinder diesel engines with an integrated oxidation catalyst is provided, such that the muffler is connected to the cylinder head of the engine, that the muffler housing is divided into two chambers, that is, an inlet chamber and an outlet chamber, by means of an intermediate wall and that the oxidation catalyst is secured in the intermediate wall such that it fludically connects together both chambers.

An engine is configured so that a muffler is affixed to the exhaust opening of the cylinder, and the air-cooled cylinder is cooled by a cooling fan. The engine is provided with a muffler cover for covering the muffler, and exhaust gas is discharged inside the muffler cover along the wall surface of the muffler. A second cooling air is combined with the exhaust gas flow from the upstream side thereof to be parallel thereto, and a first cooling air having been caused to flow under the muffler is caused to perpendicularly impinge against the exhaust gas flow on the downstream side thereof. Thus, the cooling airs are combined inside the muffler cover with the exhaust gas flow, and as a result the temperature of the exhaust gas is sufficiently reduced at the time when the exhaust gas is discharged from the opening of the muffler cover to the outside.

An engine-driven working machine capable of favorably reducing exhaust sound (that is, noise) is provided. An engine-driven working machine 10 is a generator in which an engine 15 and a muffler 67 are housed in an inside 13 of an outer case 12. The generator 10 includes a tail pipe 68 that is provided at a lower portion 67a of the muffler 67, a discharge port 37 that is disposed above the tail pipe 68, and a baffle plate 84 that is disposed to face the discharge port 37. The discharge port 37 is formed in the outer case 12. Further, cooling air that is sent from a cooling fan 17 is guided to below the muffler 67 with the baffle plate 84.

An exhaust purification system includes an exhaust passage. Exhaust gas flows through the exhaust passage. A burner is arranged in the exhaust passage. A combustion space for fuel in the burner is a part inside the exhaust passage. A NOx adsorbent is located downstream of the combustion space in the exhaust passage. The NOx adsorbent adsorbs nitrogen oxide contained in the exhaust gas. A selective reduction catalyst is located downstream of the NOx adsorbent in the exhaust passage. An adding valve is located between the selective reduction catalyst and the combustion space in the exhaust passage. A connection passage is connected to the adding valve. Urea water flows through the connection passage toward the adding valve. A part of the connection passage runs through the combustion space.

A silencing accessory or specially designed muffler to be attached to the exhaust of a portable generator, which is specially designed to reduce or eradicate excessive noise, as well as filter emissions. The present invention comprises a replaceable filter to provide a product that solves the problems of noise and air pollution created by these necessary units

An extraction apparatus (10) adapted to capture exhaust gas emitted by an internal combustion engine and to dilute the exhaust gas by mixing with air and also cool the exhaust gas. The extraction apparatus (10) has a first flow path (31), second flow path (32), and third flow path (33). The first flow path (31) extends between inlet (35) and an outlet (37) for air flow from the inlet to the outlet. The second flow path (32) receives exhaust gas emitted from the engine and delivers it into the first flow path (31) for mixing with an air flow along the first flow path. The third flow path (33) delivers water for mixing with the air flow. The arrangement is such that there is confluence of air, exhaust gas and water to provide a fluid mixture for discharging through the outlet (37). The exhaust gas is cooled using the cooling effects of the air and also the cooling effects of water in heat exchange relation with the exhaust gas prior to mixing of the exhaust gas with the air. There is also cooling of the mixture of exhaust gas and air using the cooling effects of water in heat exchange relation with the mixture, and also cooling by injection of water into the air. The various flow paths are configured for the requisite heat exchange relation.

A box-type generator driven by an engine, comprising a box-type soundproof hood assembly (3) enclosing the whole generator, a controller (2), an oil tank (19), a front and a back fans (13, 14), air ducts (11, 12), a permanent magnetic generator (4), an engine (5), a double-cavity type muffler assembly (6) and the like. With the novel designs such as forward fans air inlet (17) and controller arrangement, dual cooling air ducts and double muffler structure, and the integrated overall layout of the control system, the box-type generator ensures a generator cooling system to sequentially cool down heating components in a temperature ascending order, thus effectively reducing the system noise of a generator assembly, and facilitating the use, installation and maintenance of the generator.