Showing papers on "Muffler published in 2005"
TL;DR: In this article, a urea-based selective catalytic reduction (SCR) system was developed to satisfy both these demands, and will be introduced in the fall of 2004, and the operating conditions of vehicles in Japan are different from those in the US and Europe.
Abstract: In Japan there is currently a strong social demand for exhaust emissions reduction from heavy-duty diesel engines. Therefore, new Long-Term Regulation will come into effect in October 2005, setting the NOx standard at 2.0 g/kWh and the PM standard at 0.027 g/kWh. At the same time, customers always demand exceptional fuel economy from heavy-duty commercial vehicles. A urea-based Selective Catalytic Reduction (SCR) system was developed to satisfy both these demands, and will be introduced in the fall of 2004. The operating conditions of vehicles in Japan are different from those in the US and Europe. Basically, average vehicle speeds are significantly lower. To improve the low temperature SCR performance, an oxidation catalyst was located upstream of the SCR, and an additional oxidation catalyst was located downstream of the SCR for emergency NH3 slip. The muffler size with all three catalysts was similar to a conventional muffler. The fuel and urea water solution consumption of the system was studied and compared with the fuel consumption of a similar system equipped with EGR and a Diesel Particulate Filter (DPF) unit. The properties of the urea water solution used here were not well known at the time of this project. Therefore, the specifications and corrosion characteristics of relevant materials were investigated and suitable materials were selected. Urea water solutions freeze at around -11 deg C, so a thawing system was also developed. Vehicle tests were carried out at various conditions, during which no major problems arose.
71 citations
TL;DR: In this article, the principles of TMM for predicting the transmission loss (TL) of a muffler are summarized and the method is applied to different muffler configurations and the numerical predictions are compared with the results obtained by means of an experimental set up.
Abstract: Mufflers are widely used for exhaust noise attenuation in vehicles and machinery. Recent advances in modeling procedures for accurate performance prediction have led to the development of modeling methods for practical muffler components in commercial design. Muffler designers need simple and fast modeling tools, especially in the preliminary design evaluation stages. Finite Element and Boundary Element methods are often used to provide valid results in a wide range of frequencies. However, these methods are time-consuming, its use needs highly trained personnel and the commercial software is usually quite expensive. Therefore, plane wave based models such as the transfer matrix method (TMM) can offer fast initial prototype solutions for muffler designers. In this paper, the principles of TMM for predicting the transmission loss (TL) of a muffler are summarized. The method is applied to different muffler configurations and the numerical predictions are compared with the results obtained by means of an experimental set up. Only stationary, non-dissipative mufflers are considered. The limitation of both the experimental method and the plane wave approach are discussed. The predicted results agreed reasonably well with the measured results in the low frequency range where the firing engine frequency and its first few harmonics are the main sources of noise.
69 citations
TL;DR: An alternative procedure is proposed, in which the full equations are solved in the time domain, based on the CFD simulation of an impulsive test, so that the transmission loss may be computed and compared with measurements and other numerical approaches.
Abstract: The study of the three-dimensional acoustic field inside an exhaust muffler is usually performed through the numerical solution of the linearized equations. In this paper, an alternative procedure is proposed, in which the full equations are solved in the time domain. The procedure is based on the CFD simulation of an impulsive test, so that the transmission loss may be computed and compared with measurements and other numerical approaches. Also, the details of the flow inside the muffler may be studied, both in the time and the frequency domains. The results obtained compare favorably with a conventional FEM calculation, mostly in the ability of the procedure to account for dissipative processes inside the muffler.
58 citations
Patent•
26 Aug 2005
TL;DR: A flow-through muffler as mentioned in this paper includes a plurality of heat conducting walls, baffles, or partitions that together define the passages arranged to form acoustic waveguides, attenuators, and/or cancellation chambers.
Abstract: A flow-through muffler includes a plurality of heat conducting walls, baffles, or partitions that together define a plurality of passages arranged to form acoustic waveguides, attenuators, and/or cancellation chambers, the walls, baffles, or partitions increasing a surface area exposed to the exhaust gases to facilitate extraction of heat while attenuating or canceling the resulting sound pressure waves. The muffler may have a cooling arrangement mounted thereon, and thermoelectric generator elements or other heat-powered device, such as a reformer, connected across the heat differential between the cooling arrangement and an exterior surface of the muffler housing that is in thermal contact with the heat conducting walls, bafflers, or partitions. In addition, the muffler may be made tuneable by providing a device for varying a length of one of the passages relative to another passage, and by including a sound cancellation chamber at an intersection of the passages. In addition, the internal surfaces of the muffler may be coated with a catalyst to provide a combination muffler and catalytic converter.
52 citations
Patent•
22 Dec 2005
TL;DR: In this paper, an ultra-compact combination exhaust muffler and aftertreatment element and water trap assembly provides exhaust flow through an after treatment element surrounded by an annular water collection space receiving water diverted and shed from an upper dome cap above the exhaust manifold.
Abstract: An ultra-compact combination exhaust muffler and aftertreatment element and water trap assembly provides exhaust flow through an aftertreatment element surrounded by an annular water collection space receiving water diverted and shed from an upper dome cap above the aftertreatment element and below the upper outlet. In a further embodiment, the assembly includes housing sections separable from each other at a service joint axially between axial ends of the aftertreatment element for ease of servicing. In a further aspect, the aftertreatment element has an axial end within a housing section saving axial extension space.
46 citations
Patent•
27 Jan 2005
TL;DR: In this article, a modular replacement exhaust system was proposed for a range of vehicle applications including automobiles, motorcycles, and all terrain vehicles, consisting of a header pipe and a muffler.
Abstract: A vehicle exhaust assembly (100) for improved evacuation of exhaust gases from an internal combustion engine. The system comprises a modular replacement exhaust system having a novel header pipe (102) and muffler (104). The present invention readily adapts to a range of vehicle applications including automobiles, motorcycles, and all terrain vehicles.
43 citations
Patent•
8 Sep 2005
TL;DR: The exhaust heat recovery muffler as discussed by the authors includes a muffler unit having the outer surface of the outer pipe covered, and a switching valve that switches the flow of exhaust gas into the exhaust manifold and into the heat recovery unit.
Abstract: The exhaust heat recovery muffler includes a muffler unit having the outer surface thereof covered, an exhaust heat recovery unit disposed integrally with the muffler unit, and a switching valve that switches the flow of exhaust gas into the muffler unit and into the exhaust heat recovery unit. An outer pipe of the muffler unit and a cylindrical shell of the exhaust heat recovery unit, covering the outer circumference of the outer pipe, are coaxially disposed. The exhaust heat recovery unit includes a heat exchange chamber, formed by a pair of partitions provided between the inner circumference of the shell and the outer circumference of the outer pipe, and small-diameter pipes penetrating through the pair of partitions and extending through the heat exchange chamber. A heat exchange medium flows inside of the heat exchange chamber.
38 citations
1 Jan 2005
TL;DR: A novel scheme for the shape optimization of double-chamber mufflers by using a genetic algorithm (GA) utilizes the four-pole transfer matrix - a technique for evaluating the sound transmission loss (STL) on the basis of plane wave theory - in conjunction with the GA method.
Abstract: In an effort to meet the demands of operation and maintenance inside a constrained machine room, the volume of the muffler system is often compromised. Therefore, the need to enhance the level of muffler performance under limited space conditions becomes even more expedient in the field of practical engineering work. The present paper proposes a novel scheme for the shape optimization of double-chamber mufflers by using a genetic algorithm (GA). The new approach utilizes the four-pole transfer matrix - a technique for evaluating the sound transmission loss (STL) on the basis of plane wave theory - in conjunction with the GA method. A numerical case of the sound elimination of pure tone is discussed in this study. To achieve optimization in the GA, several test parameter values were used. Results showed that the maximum value of the STL was optimally obtained at the desired frequency of 250 Hz. The approach used in this study for optimum design of the STL is both easy and quite effective.
35 citations
Patent•
1 Feb 2005TL;DR: In this paper, the exhaust muffler and the fuel tank are attached to common cross members to improve the noise vibration characteristics of the vehicle body while suppressing an increase in the weight of vehicle body.
Abstract: At the underside of a vehicle body, a fuel tank and an exhaust muffler are disposed alongside of each other along a vehicle body longitudinal direction, with a drive shaft being disposed between the fuel tank and the exhaust muffler. The front and rear of the fuel tank are attached with tank bands to two cross members. The exhaust muffler is attached to the two cross members via rubber supports. Because the exhaust muffler and the fuel tank are attached to common cross members, the noise vibration characteristics of the vehicle body are improved while suppressing an increase in the weight of the vehicle body.
34 citations
Patent•
14 Nov 2005
TL;DR: In this article, a muffler with a housing having an inlet, an outlet, and at least one chamber is provided with a cleaning member that is disposed in the chamber.
Abstract: A muffler with a housing having an inlet, an outlet, and at least one chamber is provided with a cleaning member that is disposed in the chamber. The cleaning member is movable relative to the housing.
33 citations
Patent•
20 Jul 2005TL;DR: In this paper, an exhaust device includes an exhaust pipe connected at its upstream end to a cylinder head of the engine and an exhaust muffler connected to the downstream end of the exhaust pipe for suppressing the generation of noise from a heat insulating cover that covers a part of exhaust pipe.
Abstract: An exhaust device includes an exhaust pipe connected at its upstream end to a cylinder head of the engine and an exhaust muffler connected to the downstream end of the exhaust pipe for suppressing the generation of noise from a heat insulating cover that covers a part of the exhaust pipe. A heat insulating cover covers a portion of the exhaust pipe near the engine and a stay is fixed to the heat insulating cover. The stay includes a supporting plate portion curved so as to partially surround the outer circumference of the exhaust pipe. A first vibration isolating member is provided that is sandwiched between the outer circumference of the exhaust pipe and the supporting plate portion, a band member is tightened to mount the supporting plate portion to the exhaust pipe, and a second vibration isolating member is sandwiched between the supporting plate portion and the band member.
TL;DR: In this paper, the estimation of flow noise emission from rear mufflers in IC engine exhaust systems, through the analysis of measurements performed in a steady cold flow bench, is discussed, where the ratio between the tailpipe in-duct acoustic power and the radiated acoustic power is analyzed as a function of the Strouhal number.
TL;DR: In this article, the authors considered the three-dimensional scalar problem of acoustic propagation in a muffler and derived a homogenized impedance condition when the perforated duct is coated by an absorbing material.
Abstract: We consider the three-dimensional scalar problem of acoustic propagation in a muffler. We develop and analyze a Fredholm-type formulation for a stationary fluid in the timeharmonic setting. We prove a homogenization result for a muffler containing periodically perforated ducts. Essentially, the perforated boundaries become completely transparent when the period of perforations, which is assumed to be of the same order as the size of perforations, tends to zero. We also derive a homogenized impedance condition when the perforated duct is coated by an absorbing material. We present numerical examples in two dimensions, obtained from coupling finite elements in the muffler with modal decompositions in the inlet and outlet ducts, which demonstrate the limiting validity of the theoretical results. © World Scientific Publishing Company.
Patent•
17 Nov 2005
TL;DR: A sound-cancelling flow-through muffler includes a linear first inner passage, and a curved or zig-zagged second outer passage that wraps around or surrounds the inner passage and that is situated between the linear outer passage and an exterior wall of the muffler.
Abstract: A sound-cancelling flow-through muffler includes a linear first inner passage, and a curved or zig-zagged second outer passage that wraps around or surrounds the inner passage and that is situated between the linear first inner passage and an exterior wall of the muffler. The outer passage has a length that is equal to, or a multiple of, one-half the wavelength of sound to be cancelled by the muffler such that sound exiting the inner and outer passages destructively interferes or cancels in a sound cancellation or conversion chamber. In addition, the walls of the outer passage serve as a heat sink to extract heat from the exhaust stream and conduct the heat to the outside of the housing. Alternatively, the outer passage may have a closed such that reflects sound back toward the inner passage for cancellation, the walls of the outer passage continuing to serve as a heat sink to extract heat from the exhaust stream and conduct the heat to the outside of the housing.
Patent•
4 Feb 2005
TL;DR: In this paper, a soundproof engine-driven operating machine (SEMO) is described, consisting of an engine, a operating machine main body that is driven by the engine, and a base frame that supports the engine and the operating machine in a vibration-proof structure.
Abstract: A soundproof engine-driven operating machine has a small installation area, is easy to assemble and disassemble, and has superior cooling effects. The soundproof engine-driven operating machine comprises an engine, a operating machine main body that is driven by the engine, a base frame that supports the engine and the operating machine main body in a vibration-proof structure, and a case that is fitted to the base frame and accommodates the engine and the operating machine main body. One part of the case includes a first-storey chamber that accommodates the engine and the operating machine main body, first and second heat exchangers, each having a cooling fan and being arranged above the first-storey chamber, the first and second heat exchangers performing heat conversion relating to the operation of the engine by using the cooling fans, arranged separately in a ventilation path, and a second-storey chamber that accommodates a muffler for discharging engine air. The part of the case is comprised from a structural frame that is provided on the base frame. A cover is secured to the base frame, and covers the entire structural frame.
Patent•
26 May 2005
TL;DR: In this article, a turbocharged engine with a turbine ( 305 ) having an outlet and an inlet, and a compressor ( 307 ) having inlet and an exhaust gas treatment module ( 317 ) is disposed in fluid communication with the outlet of the turbine and the inlet of the compressor.
Abstract: A turbocharged engine ( 301 ) with a turbine ( 305 ) having an outlet ( 306 ) and a compressor ( 307 ) having an inlet ( 308 ). An exhaust gas treatment module ( 317 ) is disposed in fluid communication with the outlet ( 306 ) of the turbine ( 305 ) and the inlet ( 308 ) of the compressor ( 307 ). The exhaust gas treatment module ( 317 ) may be advantageously mounted on the base engine ( 301 ), and disposed between an exhaust aftertreatment system ( 316 ) having an outlet to atmosphere, and the turbine outlet ( 306 ). A method of operating the turbocharged engine ( 301 ) includes the steps of collecting exhaust gas, passing the exhaust gas though the turbine ( 305 ), and deciding whether to command exhaust gas recirculation (EGR). When EGR is not commanded, an EGR valve ( 311 ) is closed, and exhaust gas is passed from the turbine ( 305 ) through an exhaust aftertreatment module ( 316 ) and a muffler 133 . When EGR is commanded, the EGR ( 311 ) valve is opened, and some exhaust gas is passed from the turbine ( 305 ) through a secondary exhaust treatment module ( 317 ) and compressor ( 307 ).
Patent•
28 Mar 2005TL;DR: In this paper, a vehicle exhaust system support structure is described in which an upstream side exhaust pipe (1) connected to an engine (E) is guided to an inlet (15) of a muffler (M) supported on a vehicle body (B), and a downstream side exhaust manifold (2) coupled to an outlet (16) of the muffler is disposed in the interior of a rear bumper (RB).
Abstract: In a vehicle exhaust system support structure, an upstream side exhaust pipe (1) connected to an engine (E) is guided to an inlet (15) of a muffler (M) supported on a vehicle body (B), and a downstream side exhaust pipe (2) coupled to an outlet (16) of the muffler (M) is disposed in the interior of a rear bumper (RB). The upstream side exhaust pipe (1) and the inlet (15) of the muffler are coupled to each other via a flexible tube (20), thus floatingly supporting the upstream side exhaust pipe (1) in the muffler (M). The downstream portion of the upstream side exhaust pipe (1) passes through the interior of the flexible tube (20), and is inserted into the inlet (15) of the muffler (M).
Patent•
14 Sep 2005TL;DR: In this paper, a compressor is located downstream of the discharge plenum and a helmholtz resonator is located upstream of the muffler, where the resonator can be replaced by a new resonator.
Abstract: A compressor includes a housing and one or more working elements. A muffler is located downstream of the discharge plenum and a helmholtz resonator is located in the discharge plenum upstream of the muffler.
Patent•
22 Dec 2005
TL;DR: In this article, an improved dual phase muffler for the abatement of reduction of sound and emission pollutants such as hydrocarbons, carbon monoxide, and nitrogen oxides is presented.
Abstract: The present invention is directed to an improved dual phase muffler for the abatement of reduction of sound and emission pollutants such as hydrocarbons, carbon monoxide, and nitrogen oxides. More specifically, the muffler comprises a muffler casing, an inner chamber formed in the muffler, and a catalytically coated supported material contained within the inner chamber. The present invention is also directed to a catalytically coated metallic foam catalyst support, which optionally can be pre-coat with a metallic thermal arc sprayed layer.
Patent•
8 Mar 2005
TL;DR: In this article, a diffuser cover is attached to the housing of an internal combustion engine (IC) for coupling to an exhaust port of an IC. The diffuser covers form a trap chamber, a restricted throat, and an ejector portion.
Abstract: A muffler (10) for coupling to an exhaust port of an internal combustion engine. The muffler (10) includes a housing (12) having an exhaust inlet (20) configured to receive exhaust gas from the engine, at least one internal expansion chamber (30) and an outlet opening (48). The muffler (10) further includes a diffuser cover (22) attached to the housing (12) over the exhaust opening (48) of the housing (12) forming an exhaust outlet of the muffler. The diffuser cover (22) forms a trap chamber (50), a restricted throat (60) and an ejector portion (52). The ejector portion (52) is configured to draw in ambient air through an air inlet (54) to cool the exhaust gas as it passes through the exhaust outlet (48). The restricted throat (60) is positioned downstream from said trap chamber (50) and has a smaller cross-sectional area than the trap chamber (50) so as to increase the velocity of the exhaust gas as the exhaust gas passes through the restricted throat (60) and into the ejector portion (52) so as to aid in drawing in ambient air.
TL;DR: In this paper, the relationship between back pressure and the noise level was found to be inversely proportional, which is undesirable as the requirement is to have a quiet muffler with a small back pressure (ideal muffler), and some design considerations were proposed in order to come up with an optimum muffler design.
Abstract: The main objective of this study is to find the relationship between the back pressure and the noise level. Back pressure needs to be kept to a minimum. The relationship between the noise and the back pressure is inversely proportional; lowering the noise level at the tip will result in high back pressure. However, this relationship is undesirable as the requirement is to have a quiet muffler with a small back pressure (ideal muffler). The design of the muffler chamber separation and arrangement is essential in determining the muffler characteristics. Some design considerations are proposed in order to come up with an optimum muffler design. The results how a general shape of an average design of the muffler which would be the most suitable for the test car model.
Patent•
5 Oct 2005
TL;DR: In this paper, an environmental control system muffler including a thin wall polyetherether ketone (PEEK) cover tube, an open cell polymer attenuator tube slip fit there into and polymer end fitting securing the two tubes together and cooperating to form a pneumatic seal with the cover tube is presented.
Abstract: An environmental control system muffler including a thin wall polyetherether ketone (PEEK) cover tube, an open cell polymer attenuator tube slip fit there into and polymer end fitting securing the two tubes together and cooperating to form a pneumatic seal with the cover tube. The method of making the muffler apparatus includes the selection of tubing constructed of such PEEK corrugated construction and the open cell polymer noise attenuation construction, telescoping the tubes together and securing the end fittings thereto.
TL;DR: In this article, a method for robust tuning of individual cylinders air-fuel ratio is proposed, where the fuel injection is adjusted so that each cylinder has the same air fuel ratio in inner control loops, and the resulting airfuel ratio in the exhaust pipe is controlled with an exhaust gas oxygen sensor (EGO) in an outer control loop.
Abstract: A method for robust tuning of individual cylinders air-fuel ratio is proposed. The fuel injection is adjusted so that each cylinder has the same air-fuel ratio in inner control loops, and the resulting air-fuel ratio in the exhaust pipe is controlled with an exhaust gas oxygen sensor (EGO) in an outer control loop to achieve stoichiometric air-fuel ratio. Correction factors to provide cylinder individual fuel injection timing are calculated based on measurements of the ion currents for the individual cylinders. An implementation in a production vehicle is shown with results from driving on the highway.
Patent•
6 Jan 2005
TL;DR: In this paper, the authors proposed an engine type generator composed of an engine duct 52 for externally discharging cooling air of cooling an engine 31 and a muffler 45 in the engine types generator 10, and an exhaust duct 50 integrally forming a generator duct 51 for internally discharging the cooling air for cooling a generator 32.
Abstract: PROBLEM TO BE SOLVED: To provide an engine type generator capable of improving positional accuracy of respective members, by reducing the number of its member items, by simplifying a shape of the members for constituting a cooling air duct. SOLUTION: This engine type generator is composed of an engine duct 52 for externally discharging cooling air of cooling an engine 31 and a muffler 45 in the engine type generator 10, and an exhaust duct 50 of integrally forming a generator duct 51 for externally discharging the cooling air of cooling a generator 32. The muffler 45 and the generator 32 are arranged in parallel, and the engine duct 52 and the generator duct 51 are arranged so as to become parallel in the discharge direction of the cooling air discharged from the engine duct 52 and the generator duct 51. An exhaust duct 50 is arranged by fixing the generator duct 51 to a crankcase 31a. An opening 52a of the engine duct 52 and an opening 51c of the generator duct 51 are laterally juxtaposed, and the opening 51c of the generator duct 51 is positioned on the upper side of the generator 32. COPYRIGHT: (C)2006,JPO&NCIPI
TL;DR: In this article, a transfer matrix-based approach was used to analyze axi-symmetric circular lined plenum chambers, and a parametric study was carried out to investigate the effects of different thicknesses and placements of the absorptive lining.
Abstract: Both reflective and dissipative silencers have their respective frequency range of good and poor acoustic performances. Reflective types of muffler in general produce more back pressure than the dissipative ones. So, to take advantage of both types of mufflers and to overcome their limitations, they may be combined to give the required performance over a broad range of frequency of interest. In the present paper the combination (or hybrid) muffler is analyzed using a transfer matrix based approach by means of a two-dimensional wave modeling. The present approach can be used to analyze axi-symmetric circular lined plenum chambers also. The effectiveness of the inherent bulk reaction assumption of the present analysis is illustrated. A parametric study is carried out to investigate the effects of different thicknesses and placements of the absorptive lining. The contributions of reflective and absorptive portion of combination muffler to attenuation are investigated from the designer's point of view.
Patent•
13 May 2005TL;DR: A multi-cylinder compressor is designed to have excellent noise and pulsation reduction and also to be easy to manufacture as mentioned in this paper, which includes first and second compressing compartments partitioned from each other to perform compression of gas.
Abstract: A multi-cylinder compressor is designed to have excellent noise and pulsation reduction and also to be easy to manufacture. The multi-cylinder compressor includes first and second compressing compartments partitioned from each other to perform compression of gas, respectively, first and second mufflers equipped to discharge openings of the first and second compressing compartments, respectively, a communication flow path communicating an interior of the first muffler to an interior of the second muffler, and at least one discharge flow path extended a predetermined length from the second muffler so as to reduce noise and pulsation while guiding discharge of compressed gas.
Patent•
31 Mar 2005TL;DR: In this article, the inside of a box-shaped muffler body is divided into a first exhaust chamber and a second exhaust chamber by a partitioning member which has a third exhaust chamber formed therein.
Abstract: In an engine exhaust muffler with an exhaust emission control function, the inside of a box-shaped muffler body is divided into a first exhaust chamber and a second exhaust chamber by a partitioning member which has a third exhaust chamber formed therein. The muffler body is provided with an exhaust inlet for introducing exhaust gas from an engine into the first exhaust chamber. The partitioning member is provided with first communication bores providing communication between the first and second exhaust chambers, and second communication bores providing communication between the second exhaust chamber and the third exhaust chamber. The third exhaust chamber is open to the atmosphere through an exhaust outlet pipe. An exhaust emission control catalyst is carried on an outer surface of the partitioning member facing the first and second exhaust chambers, as well as on an inner surface of the partitioning member facing the third exhaust chamber. An inner surface of the muffler body does not carry the exhaust emission control catalyst. Thus, in this exhaust muffler, thermal damages to the adjacent devices are less, the structure is simple and inexpensive, and a loss in output from the engine is less.
Patent•
30 Dec 2005
TL;DR: In this article, the exhaust gas system of an internal-combustion engine has an exhaust gas inlet and a first flow pipe arranged inside the muffler and completely penetrating the exhaust manifold.
Abstract: A muffler for an exhaust gas system of an internal-combustion engine has an exhaust gas inlet and a first flow pipe arranged inside the muffler and completely penetrating the muffler. A shut-off device is arranged in the first flow pipe, for the shutting-off and opening-up an exhaust gas tail pipe which is situated downstream of the muffler and is connected with the first flow pipe. A second flow pipe partially penetrates the muffler, and has an overflow path between the first and second flow pipes situated inside the muffler. The first and the second flow pipes are connected with the exhaust gas inlet by way of a branching element and the shut-off device is arranged upstream of the muffler in the first flow pipe.
Patent•
17 Feb 2005
TL;DR: In this article, the authors propose an exhaust device for a motorcycle, capable of achieving output performance and noise eliminating performance suitable to either operation conditions in either a high-load operation or a low-load one while achieving compactness of the motorcycle and volume enlargement of an expansion chamber for exhaust.
Abstract: PROBLEM TO BE SOLVED: To provide an exhaust device for a motorcycle, capable of achieving output performance and noise eliminating performance suitable to either operation conditions in either a high-load operation or a low-load operation while achieving compactness of the motorcycle and volume enlargement of an expansion chamber for exhaust SOLUTION: An exhaust pipe 28 connected to an exhaust port of an engine 15 is branched to two branch exhaust tubes 31 and 32 One branch exhaust tube 31 is connected to a first exhaust muffler 21, and the other branch exhaust tube 22, to a second exhaust muffler 22 Preferably, it is provided with the first exhaust muffler 21 that is suitable to high-load operation, and the second exhaust muffler 22 that is suitable to low-load operation On the branch tube 31 on the first exhaust muffler, an opening/closing valve 35 is provided to be opened in high-load operation to send exhaust gas to the first exhaust muffler 21, and closed in low-load operation to disconnect flow of exhaust gas to the first exhaust muffler 21 COPYRIGHT: (C)2006,JPO&NCIPI
Patent•
30 Jun 2005TL;DR: In this paper, the authors proposed a noise reduction structure for a hybrid vehicle in which a cover covers at least part of an air intake system connected to an engine capable of giving power to a driving wheel, an exhaust muffler constituting part of a exhaust system, and the electric motor is covered with the common cover.
Abstract: A noise reduction structure for a hybrid vehicle in which a cover covers at least part of an air intake system connected to an engine capable of giving power to a driving wheel, an exhaust muffler constituting part of an exhaust system connected to the engine, and an electric motor capable of giving power to the driving wheel. When at least part of the air intake system, the exhaust muffler constituting part of an exhaust system, and the electric motor is covered with the common cover, heat generated by the exhaust muffler is prevented from affecting the electric motor. The rotational axis of the electric motor extends in a longitudinal direction of a body frame and is disposed forwardly of the central position of the exhaust muffler extending in the longitudinal direction.