CN113574254A

CN113574254A - Power unit for a motor vehicle

Info

Publication number: CN113574254A
Application number: CN202080020374.3A
Authority: CN
Inventors: V·J·约翰逊; K·塞尔瓦拉吉; B·玛尼; D·纳根德拉库玛
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2019-03-25
Filing date: 2020-03-18
Publication date: 2021-10-29
Also published as: WO2020194339A1

Abstract

The present subject matter relates to a power unit (200) for a motor vehicle. The power unit (200) includes a cylinder head (222) coupled to an exhaust system (205), the exhaust system (205) coupled to at least one exhaust port (261). The discharge passage (204) is disposed in fluid communication with the discharge port (261). The discharge channel (204) comprises a discharge pipe (210) forming at least a part of the discharge channel (204), and at least one treatment device (250) forming at least a part of the discharge channel (204) is arranged at an upstream end of the discharge pipe (210) and at a downstream end (263) of said discharge opening (261). At least a portion of the treatment device (250) is annularly enclosed by at least a portion of the cylinder head (222).

Description

Power unit for a motor vehicle

Technical Field

The present subject matter relates generally to a power unit for a motor vehicle, and in particular to an exhaust system for a power unit.

Background

Generally, a motor vehicle such as a compact saddle-ride type vehicle is provided with an Internal Combustion (IC) engine unit. These ride-on vehicles are popular for their compact layout and their ability to carry additional passengers and/or load thereon. These vehicles include two or three wheels depending on the application, engine layout, and the like. Some of these vehicles are equipped with a swing type engine, and a connecting link such as a toggle link is provided so as to swingably support the internal combustion engine unit. Some other types of saddle-ride type vehicles fixedly mount an internal combustion engine on a frame. In these vehicles, the internal combustion engine may be tilted forward. Therefore, these vehicles have an exhaust system that extends in the lower portion of the vehicle and extends toward a muffler body located on one side of the vehicle or located at the center. Therefore, vehicles must have sufficient ground clearance to safely accommodate the exhaust system, which is one of many packaging and layout challenges for such vehicles.

Furthermore, these ride-on vehicles operate in different terrains and in different driving modes, as these depend on the location of operation or the location of the user, which is beyond the control of the manufacturer. These vehicles may affect the exhaust system when operating in such different terrain and in different driving modes, as the exhaust system is one of the vehicle's lower-located systems.

Furthermore, when a swing type internal combustion engine is provided, it further undergoes up-and-down movement due to the swing mounting. An exhaust system directly connected to the internal combustion engine is directly subjected to such shocks from the internal combustion engine. Therefore, the exhaust system requires a robust and safe installation.

Furthermore, the exhaust system must operate in an optimal manner in order to be able to treat the exhaust gases without any system failure, even under severe use conditions. For example, poor ground clearance may damage the exhaust system, affecting the performance of the exhaust system, since the exhaust system is located substantially in the lower portion of the vehicle. Therefore, in addition to effective treatment of combusted gases, there is a need to safely contain the exhaust system.

Drawings

The detailed description describes embodiments with reference to the drawings. The same reference numbers will be used throughout the drawings to refer to similar features and components.

Fig. 1 depicts a left side view of an exemplary motor vehicle, according to embodiments of the present subject matter.

Fig. 2 illustrates a right side view of a frame member having a power unit according to an embodiment of the present subject matter.

FIG. 3 depicts a portion of a power unit according to an embodiment of the present subject matter.

FIG. 4 depicts a cross-sectional view of a portion of the power unit taken along axis X-X' of FIG. 3, according to an embodiment of the present subject matter.

Fig. 5 depicts an exploded view of a portion of an exhaust system according to an embodiment of the present subject matter.

Fig. 6(a) depicts a front perspective view and a cross-sectional view taken along axis P-P' of an exhaust system according to an embodiment of the present subject matter.

Fig. 6(b) depicts a detailed cross-sectional view of a portion of the venting system of fig. 6(a) in accordance with an embodiment of the present subject matter.

FIG. 7 depicts a front view of a portion of a motor vehicle with a power unit installed in accordance with another embodiment of the present subject matter.

FIG. 8 depicts a graphical representation of the conversion efficiency of a processing device plotted against time.

Detailed Description

Conventionally, motor vehicles are provided with treatment devices for treating the exhaust gases before they leave the exhaust system. The treatment device requires a certain light-off temperature to function. However, in the case of a vehicle having a power unit that generates less heat, or in the case of a conventional engine, during start-up, particularly during cold start-up, the power unit will not be able to generate enough heat to bring the processing device to the activation temperature. This will result in combusted gases leaving the power unit untreated or converted, whereby harmful gases may be released into the atmosphere. In general, the generated harmful gas may include various harmful components including Total Hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx). Therefore, early activation of the treatment device is required to reduce the emission of harmful gases.

For example, consider a low exhaust flow type power unit, such as a vehicle operating at relatively low engine Revolutions Per Minute (RPM) and single speed, with low exhaust temperatures, which is used with low capacity power units in high torque applications. Therefore, the processing device takes time to reach the light-off temperature. This results in poor performance of the treatment plant with poor conversion efficiency, resulting in the emission of untreated gases. FIG. 8 depicts a graphical representation of the conversion efficiency of a processing device plotted against time. Curve a depicts the conversion efficiency of the treatment in the exhaust system according to designs known in the art and as described above. As can be seen from this figure, referring to curve a, it takes longer if the process plant reaches saturation, i.e. a stable conversion point. Especially in the initial operating state of the power unit, the conversion is poor, resulting in the entry of harmful gases into the atmosphere.

Further, generally, the treatment device is disposed in the discharge pipe or in the muffler body. If the treatment device is placed inside the muffler body, the temperature will drop sharply because the muffler body is far from the combustion chamber and its exhaust port/pipe, which will delay the activation of the treatment device. However, a treatment device mounted in the exhaust duct will either occupy a large volume in the exhaust duct or will require a widening of the exhaust duct, which adversely affects the vehicle layout and the overall performance of the powertrain. Furthermore, in vehicles in which the power unit is arranged in the lower part, such as vehicles with a forward tilting engine, the ground clearance may be affected. Further, since the exhaust pipe widens in the up-down direction, the widening of the exhaust pipe further reduces the ground clearance, which is undesirable, particularly in a vehicle in which the engine is disposed substantially in the lower portion. Furthermore, such problems will occur in vehicles having a vertically or slightly forwardly inclined engine, since the front wheels (extending downward from the head pipe), the front fender, and the portion of the frame member at the front that supports the power unit are located near the exhaust pipe, causing clearance problems. Such vehicles face very serious challenges in achieving compact vehicle width, compact vehicle length, and sufficient ground clearance, along with reasonable saddle storage space. One side of the wheel well creates a limitation in the size of the wheel and the available degrees of freedom in the layout space, which is affected by the maximization of the saddle storage floor space, where the bottom side is the running ground clearance and the top side is the comfortable seat height. Typically, a skeleton-type frame structure having a substantially forward leaning or horizontal powertrain layout disposed below the skeleton would attempt to overcome the challenges where vehicle length/wheelbase is an additional challenge on the rear side.

In some designs known in the art, the treatment device will be welded to the discharge pipe at both ends or one end. This would require careful welding on the discharge pipe without causing the pipe to shift. Furthermore, this would require the replacement of the entire discharge pipe in case of failure of the treatment device, together with the muffler body, since the muffler body is also welded to the discharge system. This is not cost effective as the entire exhaust system needs to be replaced and is therefore costly. In another design known in the art, the housing of the treatment device is welded to the pipe and the treatment device is disposed within the housing, which would also require replacement of the entire exhaust system in the event of failure of any component, such as the treatment device. Thus, in either of the above designs, the gap is affected.

Further, in order to maintain the ground clearance and the manufacturing feasibility of the exhaust pipe, the processing means is provided behind the bent portion due to the presence of the bent portion in the exhaust pipe at the junction very close to the cylinder head side of the exhaust pipe. Since the treatment device is located remotely from the discharge, the time it takes for the treatment device to reach its activation temperature will be extended, adversely affecting the efficiency of the treatment device. Furthermore, such a design would require heating of the processing device using a heating system such as a coil or known methods. Such heating systems require additional accommodation space in the vicinity of the processing device, which can affect ground clearance or part clearance with other components, which is undesirable.

Furthermore, some vehicles have a discharge pipe with a smaller diameter, and housing the treatment device in such a discharge pipe would require the use of a longer treatment device that must be disposed after the bend (where the bend is located on the discharge pipe near the connection portion of the cylinder) and would have to house the treatment device along a considerable length, which again may lead to uneven heating, resulting in inefficient treatment devices. Furthermore, processing devices with larger volumes and larger diameters will have the disadvantages associated with insufficient clearance in the operational layout as described above. In such systems, to increase the efficiency of the processing apparatus, a greater amount of coating may be used, which may increase the cost of the processing apparatus. However, in the event of a failure of the treatment device, the entire exhaust system must be replaced, making the system cost-effective.

Accordingly, there is a need to address the above-mentioned and other shortcomings in the prior art. Therefore, there is a need to effectively treat the exhaust gas prior to discharge into the atmosphere. The treatment device should be safely accommodated in the exhaust pipe and have an early light-off of the treatment device, and at the same time the exhaust system should be optimally set without affecting the ground clearance and/or interfering with other auxiliary systems.

The present subject matter provides an exhaust system for a power unit of a motor vehicle. Motor vehicles include a power unit that includes an Internal Combustion (IC) engine. A cylinder head of an internal combustion engine includes an exhaust port disposed toward at least one side thereof. The exhaust system includes an exhaust pipe having one end connected to the exhaust port and the other end connected to the muffler.

In one embodiment, the power unit is of the forward tilting type, having a forwardly tilting cylinder/piston axis, which is fixedly mounted to a frame member of the motor vehicle. Accordingly, the power unit is mounted to the lower portion of the frame member.

The present subject matter has a power unit including an air intake system and an exhaust system. The air intake system includes an air control device capable of providing conditioned air and fuel through an air intake into the combustion chamber. Similarly, an exhaust system is connected to the exhaust port to purge combusted gases from the combustion chamber.

The power unit includes a cylinder portion defined by a cylinder block mounted to a crankcase of the power unit. One end of the cylinder portion is defined by a cylinder head, and the cylinder head supports the valve assembly. The valve assembly includes at least one intake valve and at least one exhaust valve. The intake passage defines a path between the intake connecting portion and the at least one intake valve. The discharge port defines a path connecting the discharge connection portion to the at least one discharge valve. The drain system is connected in fluid communication with the drain port through a drain connection.

The exhaust system includes a muffler body disposed at a downstream end thereof. An upstream end of the exhaust system is in fluid communication with at least one exhaust port of the cylinder head. The exhaust system includes an exhaust pipe and a sleeve member, wherein the exhaust pipe is disposed downstream of the sleeve member.

The exhaust system includes an exhaust passage disposed in fluid communication with the exhaust port connecting the cylinder head to the at least one muffler body. The discharge passage includes a discharge tube forming at least a portion thereof.

At least one treatment device forming at least a part of the discharge channel is arranged at the upstream end of the discharge pipe and at the downstream end of the discharge opening. At least a portion of the treatment device is annularly enclosed by at least a portion of the cylinder head forming the exhaust port. The present subject matter is characterized in that the treatment device can be accommodated compactly and safely even before the first bend of the discharge pipe. Furthermore, the disposal means is located close to the discharge opening, resulting in early light-off.

The exhaust system includes a first treatment device capable of treating combusted gases exiting the cylinder head, and the first treatment device is mounted on the cylinder head. The cylinder head is adapted to support the treatment device with a cross-sectional area of the discharge channel that increases/flares in the downstream direction, at least a part of which matches the outer diameter/diameter of the treatment device. Accordingly, one aspect of the present subject matter is that the treatment device is disposed near the exhaust valve, thereby enabling early activation of the treatment device.

The present subject matter is characterized in that the cross-sectional area of the discharge channel adapted to at least partially support the treatment device enables to make full use of the area of the treatment device, since the area of the exhaust gases leaving the discharge channel and the area of the exhaust gases entering the treatment device are substantially identical.

A treatment device is disposed at the discharge passage opening, having at least a portion mounted to the discharge passage, and a remainder of the treatment device is configured to be located within the discharge system. One feature of the present subject matter is that the treatment device is optimally configured within the exhaust system.

In one embodiment, a sleeve member annularly encloses the treatment device, wherein an upstream end of the sleeve member abuts at least a portion of the cylinder head to form a tight seal therebetween. Thus, the present subject matter allows the combusted gases or exhaust gases to exit the cylinder head and enter the treatment device even before they completely exit the exhaust passage. On the one hand, the exhaust gases passing through the exhaust pipe itself cause heating of the treatment device, even during the start-up of the power unit, leading to early light-off.

The present subject matter is characterized in that, according to one embodiment, the flaring of the discharge passage in the downstream portion reduces the time spent by the exhaust gas when passing through the treatment device. Thus, the treatment device can be effectively used to treat exhaust gas. In one embodiment, the discharge passage is gradually flared such that the exhaust gas flowing therethrough varies with the cross-section and thereby enters a treatment device having a similar cross-section, thereby improving the utilization or uniformity of the treatment device.

Regardless of the capacity of the power unit, the opening of the discharge passage may be adapted to accommodate the power unit design without affecting its performance.

In one embodiment, at least one sealing member is disposed between the contact surface of the sleeve member and the cylinder head, wherein the sealing member may have one or more contact surfaces. For example, the sealing member may be a disk, a cylinder, or a combination of a disk and a cylinder.

In one embodiment, the downstream end portion of the sleeve member includes a first flange portion extending radially therealong. Similarly, the upstream end portion of the discharge pipe is provided with a second flange portion, wherein the second flange portion is fixed to the first flange portion. Further, an interface member is provided between the first flange portion and the second flange portion so that exhaust gas can flow therebetween in a leak-proof manner.

One feature is that the sleeve member acts as a protective housing for the processing device for protecting the processing device from physical damage or from external factors that may affect function.

The sleeve member may be a cast part, a molded part, a welded sheet metal part, a cured part made of a rigid material including any known metal or fiber reinforced plastic.

One feature is that the sleeve member at least partially annularly encloses the processing device with a gap disposed therebetween, the gap acting as a heat seal to maintain the temperature of the processing device. Furthermore, the handling means are protected from any direct contact.

In one embodiment, the treatment device has a downstream end supported by the sleeve member and an upstream end supported by the cylinder head. However, in another embodiment, the treatment device has a downstream end supported by the interface member and an upstream end supported by the cylinder head. Thus, the treatment device has at least a portion sandwiched between the cylinder head and the exhaust system, thereby being safely and compactly mounted thereto.

The present subject matter is characterized in that the treatment device can be arranged before the first bend of the discharge pipe without damaging the ground clearance or interfering with other components.

The present subject matter enables the treatment device to be accommodated in a position closer to the cylinder portion, at least partially within the exhaust passage, thereby suppressing extension of the exhaust pipe.

For example, in a forward tilting type power unit, the processing device according to the present subject matter, which is at least partially accommodated in the discharge passage, suppresses expansion of the discharge pipe in a downward direction. Further, in the power unit having the discharge connection portion disposed slightly toward the vehicle lateral side, the present subject matter suppresses expansion of the discharge pipe in the vehicle lateral direction.

One aspect of the present subject matter is that the treatment device is disposed before the first bend of the discharge tube. This may be the first processing means, which may be a preliminary processing means or a main processing means. For example, if a preliminary treatment device is provided in accordance with the present subject matter, the main treatment device may be provided at any point after the first bend or on the rest of the discharge pipe, as long as the discharge pipe has a sufficient length available, due to the compact design of the discharge system of the present subject matter.

On the one hand, even in a vehicle in which the power unit is arranged in the lower part of the body frame, the ground clearance is not affected, since at least a part of the processing device is accommodated in the discharge opening and arranged in front of the first bend, which will be one of the lower points of the vehicle. Thus, the ground clearance of the vehicle is not affected, while the processing device is safely disposed away from any impact caused by bumpy or uneven terrain.

On the other hand, no adapter or other means for welding is required to accommodate the processing device, thereby eliminating weak points due to the need for welding or welding itself. Thus, the present subject matter is cost effective because it eliminates the need for additional adapters and the need for welding and the like, thereby saving time and cost.

One feature of the present subject matter is that the treatment device is arranged upstream of the discharge pipe, which may have a smaller diameter, in particular for vehicles with a low floor, while the desired ground clearance is thereby also achieved. Furthermore, the use of a smaller diameter discharge tube may save on material costs.

Furthermore, the scope of the present subject matter is not limited to an exhaust system having a primary treatment device disposed in an exhaust pipe and a primary treatment device disposed in a muffler, as it applies to an exhaust system having the following conditions: one of the primary treatment means or the main treatment means is disposed in the discharge duct and the other of the primary treatment means or the primary treatment means is disposed in the first section, since the first section is capable of accommodating any treatment means.

These and other advantages of the present subject matter will be described in more detail in connection with embodiments of a two-wheeled saddle-type vehicle and the accompanying drawings in the following description.

An arrow provided anywhere in the upper right corner of the drawing indicates a direction relative to the vehicle, where an arrow F indicates a front direction, an arrow R indicates a rear direction, an arrow UP indicates an upward direction, an arrow DW indicates a downward direction, an arrow RH indicates a right side, and an arrow LH indicates a left side.

Fig. 1 illustrates a left side view of an exemplary two-wheeled vehicle, in accordance with embodiments of the present subject matter. The vehicle 100 has a frame member 105, and the frame member 105 serves as a structural member of the vehicle 100. The frame member 105 includes a head tube 106, and the steering assembly is rotatably coupled in an axial-radial manner (jounaled) by the head tube 106. The steering assembly includes a handlebar assembly 110 connected to front wheels 115 by one or more front suspensions 120. The front fender 125 covers at least a portion of the front wheel 115. Further, the frame member 105 includes a main frame 107 extending rearward and downward from the head pipe 106. The fuel tank 130 is mounted to a main frame 107 (also referred to as a skeleton frame) at a downward extending portion thereof. Further, the main frame 107 extends substantially horizontally rearward from a rear portion of a downward extending portion of the main frame 107, which is referred to as a downward frame 108. Further, the frame member 105 includes one or more rear frames 109, and the rear frames 109 extend rearward from the rear portion of the lower frame 108. In a preferred embodiment, the frame member 105 is a single tube type or a single tube skeleton type, which extends from the front F to the rear R of the vehicle 100. In a preferred embodiment, the frame member 105 has a single-tube frame structure with a skeleton-type structure.

The power unit 200 is mounted to the lower frame 108. In one embodiment, power unit 200 includes an internal combustion engine having at least one cylinder and operating at a lower maximum engine Revolutions Per Minute (RPM), with a higher low end torque configuration and single speed transmission. In another embodiment, power unit 200 further includes an electric motor operating in conjunction with the internal combustion engine. The fuel tank 130 is functionally connected to the power unit 200. In a preferred embodiment, the power unit is of the forward tilting type, i.e. the piston axis of the engine is tilted forward. The power unit 200 is functionally coupled to the rear wheels 140 through a transmission system. The swing arm 145 is swingably connected to the frame member 105, and the rear wheel 140 is rotatably supported by the swing arm 145. One or more rear suspensions 150 are connected to the swing arm 145 at an angle to simultaneously receive radial and axial forces due to wheel reaction forces, the one or more rear suspensions 150 being fixed to the frame member 105. The rear fender 155 is provided above the rear wheel 140 and can cover at least a part of the rear wheel 140. The seat assembly 160 is disposed rearward of the stride portion 170 of the vehicle. The bottom plate 165 is mounted to the lower frame 108, the lower frame 108 is a lower portion of the frame member 105, and the bottom plate 165 is disposed at the stride portion 170. However, the stride portion 170 is optional, and the space may be filled with a storage component for storing baggage or energy storage elements. In one embodiment, the seat assembly 160 includes a rider seat 161 and a rear seat 162 and is positioned substantially above the rear wheels 140. The base plate 165 covers at least a portion of the power unit 200. In addition, the vehicle 100 is provided with at least one set of foot pedals 180 for the rider/rear seat passenger to rest their feet.

Power unit 200 includes an air intake system (not shown), an exhaust system 205 (shown in FIG. 2). The air intake system includes an air-fuel control device capable of providing a regulated flow of air and fuel through an air intake into the combustion chamber. Similarly, exhaust system 205 is connected to exhaust 261 (shown in FIG. 4) to purge combusted gases from the combustion chamber.

Fig. 2 illustrates a right side view of the frame member 105 having a power unit 200 suspended therefrom, according to an embodiment of the present subject matter. The power unit 200 includes a cylinder portion (not shown) defined by a cylinder block 220, and the cylinder block 220 is mounted to a crankcase 221 of the power unit. The cylinder block 220 supports a cylinder head 222 that includes valve assemblies. In the present embodiment, a single cylinder type power unit is depicted. However, the present subject matter is applicable to a multi-cylinder type power unit. The valve assembly includes at least one intake valve 236 (shown in FIG. 4) and at least one exhaust valve 260 (shown in FIG. 4) that enable an air-fuel mixture to enter the cylinder portion through an intake port and purge combusted gases from the cylinder portion through an exhaust port. In this embodiment, the power unit 200 is suspended from the frame member 105 at the lower portion 108 of the frame member 105, which frame member 105 is the lower frame 108 in this embodiment. The exhaust system 205 is connected to the exhaust at an exhaust connection 226 (as shown in fig. 5), and the exhaust system 205 extends laterally and rearward toward the rear of the vehicle 100. The exhaust system 205 includes a muffler body 270 disposed at a downstream end portion of the exhaust system 205, wherein the muffler body 270 is capable of reducing noise generated during combustion, and the muffler body 270 is capable of accommodating at least another exhaust treatment device therein. Further, in the power unit 200, as shown in fig. 2, an air control device 195 including a throttle body or a carburetor is provided at an upper portion thereof.

In the depicted embodiment, exhaust system 205 extends from cylinder head 222 below foot pedal 180 and below cooling hood 224 of power unit 200. A cooling shroud 224 covers at least a portion of power unit 200 to provide forced air cooling (not shown) by a cooling fan.

In the depicted embodiment, the power unit 200 is secured to the frame member 105 by a mounting bracket 190, the mounting bracket 190 being secured to the lower frame 108 (shown in fig. 1). The mounting bracket 190 is also capable of supporting a large Capacitive Discharge Ignition (CDI) coil. The configuration of the CDI coil mounting scheme does not affect the interface components. Additional CDI supports can be used to mount the CDI coils without interfering with the packaging of other components. This provides accessibility, ease of assembly and maintenance. Furthermore, the CDI coil can be accessed separately.

In another embodiment, power unit 200 may be swingably connected to frame member 105, and the connection is made at a substantially lower portion of frame member 105.

Exhaust system 205 includes an exhaust passage 204, exhaust passage 204 functionally connecting muffler body 270 to cylinder head 222. The discharge passage 204 includes a discharge pipe 210, and the discharge pipe 210 has a downstream end portion connected to a muffler body 270. Upstream end 211 of exhaust system 205 is in fluid communication with exhaust port 261 (shown in FIG. 4) via sleeve member 215 (shown in FIG. 3). In an embodiment, the exhaust pipe 210 is fixed to the cylinder head 222 along with the sleeve member 215 at the connection portion of the cylinder head 222.

FIG. 3 illustrates a detailed view of a cylinder head and a portion of an exhaust system according to an embodiment of the present subject matter. FIG. 4 shows a cross-sectional view of a drainage system having a cross-section taken along axis X-X' according to the embodiment of FIG. 3. The exhaust system 205 includes a first treatment device 250 configured to treat combusted gases exiting the cylinder head 222. The first treatment device 250 is disposed near the discharge port 261 such that the treatment device 250 achieves early light-off even under cold start conditions.

Further, the treatment device 250 is capable of treating combusted gases passing therethrough, commonly referred to as exhaust gases. The processing device 250 is constituted by a cover 251 and a substrate 252 (as shown in fig. 6 (b)). The cover 251 serves as a housing and a structural member that holds the substrate 252. The substrate 252 of the processing device 250 typically supports a catalytic material, such as platinum or any other alternative material, and is also referred to as a "processing device support". The substrate can provide a large surface area. For example, the substrate may have a honeycomb structure. However, depending on the application, the substrate 252 may have any other known structure including at least a first pattern covering a specific portion thereof and a second pattern covering the remaining portion of the substrate portion.

The cylinder head 222 includes at least one exhaust valve 260, which exhaust valve 260 is timed to open and close according to engine performance requirements using a camshaft assembly (not shown) that will be mounted on the top 225 of the cylinder head 222. The cylinder head 222 includes a spark plug mount 235 for securing a spark plug thereto. Exhaust port 261 is the portion of the cylinder defined in cylinder head 222 that enables combusted gases to pass from the cylinder portion to exhaust system 205. In other words, the discharge port 261 can guide the exhaust gas from the combustion chamber toward the outside of the cylinder head 222. The discharge port 261 has a cross-sectional area 262 that increases in the downstream direction. The cross-sectional area 262 is enlarged to substantially match the cross-sectional area/diameter D1 of the treatment device 250. In other words, the exhaust port 261 of the cylinder head 222 may be adapted to flare in a downstream direction to match the profile/diameter D1 of the treatment device 250 (as shown in fig. 6 (b)). Thus, the increased cross-sectional area 262 of the discharge orifice 261 enables the gas exiting the discharge passage to fully utilize the area of the processing apparatus 250 to provide better area utilization or uniformity index.

As depicted in fig. 4, according to one embodiment, the treatment device 250 is disposed at the discharge port 261. In other words, the treatment device 250 is disposed at the mouth of the exhaust port 261, whereby at least a portion 213 of the cylinder head 222 annularly encloses at least a portion 214 of the treatment device 250.

Further, the sleeve member 215 annularly encloses the treatment device 250, with the upstream end 217 of the sleeve member 215 abutting at least a portion of the cylinder head 222, forming a tight seal therebetween. In one embodiment, a disc or tube sealing member 218 (shown in FIG. 5) is disposed between the contacting surfaces of the sleeve member 215 and the cylinder head 222. Further, the sleeve member 215 includes a cylindrical profile. However, the sleeve member 215 may be adapted to accommodate the handling device 250, wherein the profile of the sleeve member 215 has a complementary profile to the profile of the handling device 250. Further, the downstream end portion of the sleeve member 215 includes a first flange portion 216 extending in the radial direction thereof. Further, the upstream end 211 of the discharge pipe 210 is provided with a second flange portion 212, wherein in the assembled state the second flange portion 212 is arranged adjacent to the first flange portion 216. The downstream end portion of the discharge pipe 210 extends rearward of the motor vehicle 100 after passing through the first bend 206. Further, an interface member 230 is disposed between the first flange portion 216 and the second flange portion 212 such that exhaust gas can flow therebetween in a leak-proof manner. The interface member 230 is sandwiched between the first flange portion 216 and the second flange portion 212. The exhaust channel 204 includes an interface member 230 to form a fluid connection with the downstream end 254 (shown in fig. 6 (b)) of the treatment device 250.

Fig. 5 depicts an exploded view of a portion of an exhaust system according to an embodiment of the present subject matter. The cylinder head 222 includes an exhaust connection 226, and the exhaust system 205 is connected at the exhaust connection 226. The discharge connection part 226 includes two or more connection holes 227 disposed at a radially outer side of the discharge connection part 226. In one embodiment, the connection holes 227 are disposed in line and substantially orthogonal to the axis of the discharge port 261. In another embodiment, one of the connection holes 227 may be disposed outward/inward with respect to the other connection hole 227.

The discharge passage 204 has a discharge axis D-D ' taken at the treatment device 250, wherein the downstream end of the discharge orifice 261 is aligned with the discharge axis D-D ' and the upstream end 211 of the discharge pipe 210, as well as D-D '. Thus, alignment along the discharge axis D-D' may enable streamlined flow of the exhaust gas. Further, by optimally using the surface of the treating device 250 due to the uniform flow, uniformity of the flow of the exhaust gas from the discharge port 261 to the discharge pipe 210 is generated.

The treatment device 250 is mounted such that the discharge 261 at least partially covers the treatment device 250. In other words, the treatment device 250 will be mounted to the discharge orifice 261 (shown in fig. 4) through the mouth such that it is at least partially located in the discharge orifice 261. In one embodiment, depending on the length and cross-sectional area of the vent 261, a majority of the treatment device 250 will be disposed within the vent 261. Therefore, even in the starting state of the motor vehicle, the temperature around the discharge port quickly reaches a high temperature, so that the processing device is quickly warmed up.

Further, the sleeve member 215 is disposed adjacent the cylinder head 222 at the exhaust connection portion 226 with the sealing member 218 disposed therebetween. In another embodiment, to improve sealing, the sealing member 218 is adapted to provide a face/axial abutment and also a radial abutment to further improve sealing.

Further, the discharge tube 210 is functionally connected to the sleeve member 215 to be in fluid communication. In one embodiment, the interface member 230 is integrally formed with the discharge tube 210. Further, the interface member 230 includes an extension portion 231, which passes through the second flange portion 212 and extends toward the other side of the second flange portion 212, thereby forming a leakage preventing structure. Additionally, a universal mounting device (e.g., bolts 265) is used to secure exhaust system 205 to cylinder head 222. In one embodiment, the universal mounting bolt 265 passes through the second flange portion 212 and the first flange portion 216 to be secured to the connection hole 227. Accordingly, the universal mounting bolt 265 is able to maintain a desired alignment between all of the elements forming the discharge pipe 210. According to another embodiment, the mounting means may be a stud integral with the cylinder block 220.

Thus, combusted gases or exhaust gases exiting the cylinder head even before they completely exit the region of the exhaust port 261, and thus enter the treatment device 250 before the exhaust gases drop in temperature due to convection. In addition, the widened portion of the discharge orifice 261 provides an increased cross-sectional area (also referred to as flaring), thereby reducing the amount of time spent by the exhaust gas as it passes through the treatment device 250. Furthermore, regardless of the capacity of the power unit, the opening of the discharge passage may be adapted to accommodate the design of the power unit without affecting its performance.

Fig. 6(a) depicts a front perspective view and a cross-sectional view taken along axis P-P' of an exhaust system according to an embodiment of the present subject matter. Fig. 6(b) depicts a detailed view of a portion of a cross-sectional view of a drainage system according to the embodiment of fig. 6 (a). In the case of a power unit having a forwardly inclined cylinder portion, the exhaust port 261 extends downward or sideways downward, and the exhaust system 205 is connected to this exhaust port 261. The present subject matter enables the processing device 250 to be disposed closer to the cylinder portion. Further, even in such a cylinder portion of the forward-inclined type, since the treating device 250 is at least partially disposed within the discharge port 261, the ground clearance is not affected, whereby the distance between the cylinder portions is reduced and the efficiency of the treating device is improved.

Further, considering fig. 6(b) in conjunction with fig. 5, the present subject matter enables replacement of only the processing device 250 when the processing device 250 fails. Because the treatment device 250 is supported by the sleeve member 215 between the cylinder head 222 and the exhaust pipe 210, the present subject matter enables access to the treatment device 250 for repair or replacement treatments. Thus, the present subject matter is cost effective because the entire exhaust system need not be replaced when a treatment device fails.

In one embodiment, the cylinder head 222 is provided with at least one secondary port 267 at the exhaust port 261. The secondary vent 267 may be used to mount an oxygen sensor, secondary air injector outlet pipe, exhaust gas recirculation inlet pipe, etc.

Further, the treatment device 250 has a first length L1, and the sleeve member has a second length L2, both L1 and L2 being axial lengths. In one embodiment, the first length L1 and the second length L2 are substantially equal. In the depicted embodiment, the treatment device 250 is disposed outwardly from the sleeve member 215 at an (axial) offset L3, wherein this enables the treatment device 250 to be installed or disposed in the vent 261. In addition, the offset L3 also enables the discharge pipe 210 to be optimally positioned away from the ground as it moves upward. The offset L3 is caused by the protruding part 219 of the handling means 250.

The sleeve member 215 substantially annularly encloses the treatment device 250, thereby protecting the treatment device 250 from foreign matter (e.g., stones), dirt, or water splash that affects the physical or performance characteristics of the treatment device 250. Thus, the processing device 250 is protected from undesirable quenching or cooling. Thus, although power unit 200 is disposed substantially in the lower portion of the vehicle and exhaust system 205 is disposed substantially in the lower portion, the performance of treatment device 250 is only improved.

Further, in a bare vehicle application having power unit 200 and exhaust system 205 that are substantially exposed to the atmosphere, treatment device 250 is protected from sudden drops in temperature because sleeve member 215 acts as a heat seal that maintains temperature around treatment device 250. Thus, the sleeve member 215 also functions as a protective member while functioning as a housing. In one embodiment, a gap is maintained radially between the handling device 250 and the sleeve member 215, thereby providing a heat seal therebetween, thus eliminating any need for welding.

Further, as shown in fig. 6(a), the discharge pipe 210 has the first bent portion 206 immediately after the second flange portion, because the present subject matter can achieve such a bent portion despite housing the processing device 250. Further, according to the present subject matter, the discharge pipe 210 may have one or more bends 207 according to the course thereof, and the one or more bends 207 are in the lateral direction or in the upward direction. Thus, the present subject matter enables compact containment of the exhaust system 205 in the vehicle 100 without affecting the ground clearance of the vehicle 100 and the location of other auxiliary components, while achieving good wheel well layout space, compact vertical packaging, low floor space availability and adequate ground clearance, and compact vehicle length/wheelbase.

FIG. 7 depicts a front view of a portion of a vehicle having a power unit, according to an embodiment of the present subject matter. It can be seen that the power unit 200 is of the forward leaning type. According to one embodiment, the drain connection portion 226 of the drain 261 (shown in fig. 4) is substantially downward and the lateral sides are slightly inclined. The exhaust system 205 is connected to the exhaust connection portion 226, and extends downward from the exhaust connection portion 226 and then rearward toward the muffler body 270 of the vehicle 100. Further, the discharge system 205 includes a discharge pipe 210 having a substantially uniform diameter. Furthermore, the treatment device 250 is mounted to the discharge port 261 through a port or at least partially to the discharge port 261. The sleeve member 215 and the discharge pipe 210 support the discharge pipe 210 around the discharge port 261. The muffler body 270 is fixed to the frame member 105 by a muffler bracket 271.

As shown in fig. 7, the discharge passage is substantially inwardly accommodated with reference to an imaginary line 280 passing through the outer periphery of the power unit 200 in a front view of the vehicle. Thus, power unit 200 in the width direction RH-LH of vehicle 100 is restrained, thereby protecting exhaust system 205 from contact with any external objects that may damage system 205. Further, the processing device 250 as the heat releasing device is disposed safely away from the foot board 180 of the rider, thereby improving the driving comfort.

FIG. 8 depicts a graphical representation of the conversion efficiency of a processing device plotted against time. Curve B shows the conversion efficiency of a processing apparatus according to an embodiment of the present subject matter. It can be seen that treatment device 250 provides improved conversion efficiency when power unit 200 is started. Treatment device 250 provides improved conversion efficiency due to the treatment device 250 being disposed near discharge port 261 (shown in fig. 4). Further, the placement of the treatment device 250 proximate the exhaust port 261 provides improved conversion efficiency even in power units having low flow rates and operating at lower rotational speeds (RPM). Further, region C, which is an additional region below curve B, depicts the improved conversion provided by the subject exhaust system 205.

It should be understood that aspects of the embodiments are not necessarily limited to the features described herein. Many modifications and variations of the present disclosure are possible in light of the above disclosure. Therefore, within the scope of the claims of the present disclosure, the present disclosure may be practiced other than as specifically described.

List of reference marks

100 vehicle

105 frame member

106-head pipe

107 main frame

108 lower frame/lower part

109 rear frame

110 handle assembly

130 fuel tank

140 rear wheel

145 swing arm

155 rear mudguard

160 seat assembly

161 rider seat

162 rear seat

165 baseboard

170 stride portion

180 foot pedal

190 mounting bracket

195 air control apparatus

200 power unit

204 discharge channel

205 discharge system

206 first bend

207 curved part

210 discharge pipe

212 second flange portion

213 (of the cylinder head)

214 (of the processing device)

216 first flange portion

218 sealing member

219 projection

220 cylinder block

221 crankcase

222 cylinder cover

224 cooling jacket

225 top of

226 connecting part

227 connecting hole

230 interface member

235 spark plug mounting

236 air inlet valve

250 first processing device/processing device

254 downstream end portion

260 exhaust valve

261 discharge port

262 cross-sectional area

265 universal mounting bolt

270 muffler body

280 imaginary line

L1 first length

L2 second length

L3 offset

D1 diameter

D-D' discharge axis

Claims

1. A power unit (200) for a motor vehicle (100), the power unit (200) comprising:

a cylinder head (222) comprising at least one intake port and at least one exhaust port 261, the at least one exhaust port 261 being capable of directing exhaust gases from a combustion chamber towards the outside of the cylinder head (222);

an exhaust system (205) connected to the at least one exhaust port (261) of the cylinder head (222) at an exhaust connection portion (226), the exhaust system (205) comprising:

a discharge channel (204) disposed in fluid communication with the discharge port (261), the discharge channel (204) functionally connecting the cylinder head (222) to at least one muffler body (270), and the discharge channel (204) including a discharge pipe (210) forming at least a portion of the discharge channel (204); and

at least one treatment device (250) forming at least a portion of the exhaust passage (204), the treatment device (250) being disposed at an upstream end of the exhaust pipe (210) and a downstream end of the exhaust port (261), and at least a portion of the treatment device (250) being configured to be mounted on and annularly enclosed by at least a portion of the cylinder head (222).

2. The power unit (200) of claim 1, wherein the exhaust system (205) includes a sleeve member (215), the sleeve member (215) is configured to at least partially enclose the treatment device (250), and the sleeve member (215) is secured to the exhaust connection portion (226) of the cylinder head (222).

3. The power unit (200) of claim 2, wherein the disposal device (250) is disposed axially offset (L3) with respect to the sleeve member (215), wherein the disposal device (250) at least partially protrudes outwardly from the sleeve member (215), and a protruding portion (219) of the disposal device (250) is received at the drain opening (216).

4. The power unit (200) of claim 1, wherein the exhaust port (216) of the cylinder head (222) is adapted to flare in a downstream direction to match a diameter (D1) of the treatment device (250).

5. The power unit (200) of claim 1, wherein the exhaust passage (204) includes an interface member (230) to form a fluid connection between a downstream end (254) of the treatment device (250) and the exhaust pipe (210), and wherein a sleeve member (230) of the exhaust system (205) at least partially annularly overlaps the interface member (230).

6. The power unit (200) of claim 5, wherein the interface member (230) is sandwiched between the sleeve member (215) and the second flange portion (212) of the drain pipe (210).

7. The power unit (200) of claim 5, wherein the discharge passage (204) includes a discharge axis (D-D ') taken from the treatment device (250), wherein a downstream end of the discharge port (261) is aligned with the discharge axis (D-D ') and an upstream portion (211) of the discharge pipe (210) is aligned with the discharge axis (D-D ').

8. The power unit (200) of claim 1, wherein the exhaust system (205) is secured to the cylinder head (222), the cylinder head (222) being secured by one or more universal mounting devices (265), the universal mounting devices (265) extending through the second flange portion (212) and the first flange portion (216).

9. The power unit (200) of claim 1, wherein the discharge passage (204) includes a first bend (206) formed on the discharge pipe (210), the processing device (250) is disposed upstream of the first bend (206), and the first bend (206) is formed to change a direction of the discharge passage (204) in at least one of a lateral direction and a downward direction with respect to the motor vehicle (100).

10. The power unit (200) of claim 2, wherein the exhaust system (205) includes a seal member (218), the seal member (218) disposed between an exhaust connection portion (226) and the sleeve member (215), and the seal member (218) provides at least one of axial and radial abutment.

11. The power unit (200) of claim 1, wherein the vent channel (204) is substantially inwardly received relative to an imaginary line (280) passing through an outer periphery of the power unit (200).

12. The power unit (200) of claim 1, wherein the power unit (200) is of a forward leaning type, the power unit (200) is secured to a lower portion (108) of the frame member (105) by at least one of a fixed mount and a swingable mount, the frame member (105) is a mono-tubular frame, and the power unit (200) has a high-low end torque at lower revolutions per minute.

13. A motor vehicle (100) comprising:

a frame member (105); and

at least one power unit (200), the power unit (200) being secured to a lower portion (108) of the frame member (105) by at least one of a fixed mount and a swingable mount, the power unit (200) comprising:

a cylinder head (222) comprising at least one intake port and at least one exhaust port (261), said exhaust port (261) being capable of directing exhaust gases from a combustion chamber towards the outside of said cylinder head (222);

at least one treatment device (250) forming at least a portion of the exhaust passage (204), the treatment device (250) being disposed at an upstream end of the exhaust pipe (210) and a downstream end (263) of the exhaust port (261), and at least a portion of the treatment device (250) being configured to be mounted and annularly enclosed by at least a portion of the cylinder head (222).

14. A cylinder head (222) for a power unit (200), the cylinder head (222) comprising:

at least one exhaust port (261) configured to direct exhaust gases from a combustion chamber of the power unit (200) toward an outside of the cylinder head (222); and

an exhaust connection portion (226) for connecting an exhaust system (205) at an exhaust connection portion (226), the exhaust system (205) comprising an exhaust channel (204), at least one treatment device (250) forming at least a part of the exhaust channel (204), and the treatment device (250) being arranged at a downstream end (263) of the exhaust port (261), and at least a part of the treatment device (250) being annularly enclosed by at least a part of the cylinder head (222), and

the discharge opening (216) is adapted to open in a downstream direction to match a diameter (D1) of the treatment device (250).