CN110494643B

CN110494643B - Air induction system for two-wheeled vehicle

Info

Publication number: CN110494643B
Application number: CN201880024263.2A
Authority: CN
Inventors: M·安纳马拉; V·拉贾凯萨文; K·文卡塔纳加苏达喀尔; S·奇丹巴拉姆
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2017-03-02
Filing date: 2018-02-28
Publication date: 2021-10-29
Anticipated expiration: 2038-02-28
Also published as: CN110494643A; BR112019018086A2; WO2018158698A1

Abstract

A cylinder head (204) of an internal combustion engine (101) includes two intake valves, a swirl intake valve (308) and a tumble intake valve, operating within a swirl port (501) and a tumble port (502). The charge is injected into the swirl port and the tumble port respectively by a fuel injection valve (301). The mixing zone (620) is facilitated by the position of the fuel injection valve, wherein the fuel spray is injected into the mixing zone (620) towards the swirl and tumble ports. The ratio of the vertical distance (a) between the fuel spray point (P) and the base of the port end (Y-Y) to the cross-sectional width (E, F) of at least one of the two intake ports is between 1.5 and 3. The present invention provides charge inlets from swirl and tumble ports to ensure adequate charge distribution and avoid undesirable engine noise.

Description

Air induction system for two-wheeled vehicle

Technical Field

The present subject matter relates generally to two-or three-wheeled saddle-type vehicles. More particularly, the present subject matter relates to an air intake duct for an induction system of a two-wheeled vehicle.

Background

Intake systems play an important role in Internal Combustion (IC) engines and affect drivability, provide increased mileage and generate desired torque. The sensing system includes a pressurized fuel pump, fuel injection valves, an ECU, a throttle valve, an intake pipe, an air cleaner, and various sensors that provide inputs to the ECU. The fuel injection valve introduces fuel directly inside the IC engine or inside the intake pipe in the form of a fuel spray formed by atomization of the fuel at high pressure through a small nozzle. Air induction systems with fuel injection have many advantages such as cleaner and more complete combustion, minimal fuel loss, higher valve sensitivity, and preventing excessive fuel from entering the IC engine. Overall, this improves IC engine performance and has better cold start characteristics. The position and orientation of the fuel injection valve is important because it provides advantages in terms of improved combustion, accessibility of the fuel injection valve, and connectivity of various inputs to the fuel injection valve. Generally, to improve combustion efficiency and achieve desired air fuel mixture combustion characteristics in an IC engine, the IC engine includes a cylinder head having an inlet port. In two-wheeled vehicles, such as scooter-type vehicles having a head with two inlet ports, installation and placement of the fuel injection valve is a challenge. However, installing a fuel injection valve in an air induction system setting is challenging due to the presence of two intake ports and the loss of fuel during the fuel injection valve injecting fuel to both intake ports. Two-wheeled vehicles having a cylinder head with two inlet ports have attractive features for increased mileage and fuel efficiency, and improved IC engine performance is of great importance.

Disclosure of Invention

The present invention has been devised in view of the above circumstances.

The internal combustion engine includes a cylinder head. The cylinder head includes two intake valves, a swirl intake valve and a tumble intake valve operating within the swirl port and the tumble port. Atmospheric air from the throttle valve body and fuel injected through the fuel injection valve enter the swirl port and the tumble port, respectively. The short-circuiting portion forming the mixing region facilitates the position of the fuel injection valve in which the fuel spray is injected into the mixing region toward the swirl port and the tumble port. To facilitate mounting of the fuel injection valve, the intake pipe is provided with an injector region having a mounting flange and an opening allowing the fuel injection valve to enter. The mixing region of the air inlet tube is suitably dimensioned such that the ratio of the vertical distance from the end of the air inlet tube to the tip of the partition wall in the mixing region to the cross-sectional width of at least one. The two inlet ports are between 1.5 and 3.

It is an object of the present invention to provide charge inlets from swirl and tumble ports to ensure adequate charge distribution and avoid undesirable engine noise.

The summary of the invention provided above explains the essential features of the invention, and does not limit the scope of the invention. The nature and further features of the invention will become more apparent from the following description with reference to the accompanying drawings.

Drawings

The detailed description is described with reference to the accompanying drawings. The same reference numbers are used throughout the drawings to reference like features and components.

Fig. 1 shows a left side view of a two-wheeled vehicle employing an embodiment of the present subject matter.

Fig. 2 illustrates an enlarged and right side view of an internal combustion engine having an air induction system according to one embodiment of the present subject matter.

Fig. 3 shows a cross-sectional view of an internal combustion engine and intake air pipe according to an embodiment of the present subject matter.

FIG. 4 shows an exploded view of a cylinder head, intake air conduit, and fuel injection system according to an embodiment of the present subject matter.

Fig. 5 illustrates a front view of a cylinder head according to an embodiment of the present subject matter.

Fig. 6a shows an isometric view of an air inlet tube according to an embodiment of the present subject matter.

Fig. 6b shows another isometric view of an air inlet tube according to an embodiment of the present subject matter.

Fig. 6c shows a front view of an air inlet tube according to an embodiment of the present subject matter.

Fig. 7 shows a cross-sectional view of an intake pipe with a fuel injection system according to an embodiment of the present subject matter.

Detailed Description

Various features and embodiments of the inventive subject matter will become apparent from the following further description, which is set forth below. According to one embodiment, an internal combustion engine (IC) as described herein operates in four cycles. Such an IC engine is mounted in a two-wheeled straddle-type vehicle. It is contemplated that the concepts of the present invention may be applied to other types of vehicles that fall within the spirit and scope of the present invention. A detailed description of the constitution of the other parts than the essential parts constituting the present subject matter is omitted where appropriate.

Supplying an optimal air and fuel mixture is critical to proper combustion within an IC engine. If the mixture is not proper (lean or rich), improper combustion can result, affecting IC engine performance and resulting in increased exhaust emissions. Maintaining an appropriate air and fuel mixture ratio is critical, and varying the supply ratio and rate based on real-time IC engine operating data greatly improves IC engine performance. The air intake system can be of essentially two types, namely a fuel injection system and a carburettor system. The fuel injection system electronically injects and controls the air-fuel mixture based on certain parameters determined by various sensors. The carburetor mechanically controls the air-fuel mixture based on a throttle valve applied by a rider of the two-wheeled vehicle. The intake system and the fuel injection system play an important role in order to provide an IC engine with smooth drivability, increased mileage, improved power and torque.

Generally, an intake system includes an air cleaner, an intake passage, a throttle body, a fuel injection valve, and an intake pipe. The air cleaner draws air from the atmosphere and filters it, and then supplies the air to downstream components. The air filter passage directs air flow from the air filter through a throttle body that includes a venturi and a butterfly valve through which air is throttled to control the rate of air intake based on throttle control by a rider. The throttled air is directed through an intake duct to a plurality of intake ports of the IC engine. The plurality of intake ports form a portion of a cylinder head of the IC engine, which guides an air-fuel mixture to the combustion chamber. The outlets of the plurality of intake ports are controlled by the same number of intake valves configured to be operatively connected to open and close to match the four cycles of the IC engine. The fuel injection valve is provided so that fuel is injected into the throttle air in the intake pipe after throttling. The fuel injection valve introduces fuel directly into the IC engine or in the intake pipe in the form of a fuel spray formed by atomizing the fuel through a small nozzle at high pressure. The fuel injection valve may be mounted on the throttle body or the intake pipe. Various sensors exist that determine the IC engine operating state and riding conditions, and an Electronic Control Unit (ECU) regulates the air-fuel mixture based on these inputs. There is a fuel pump configured to supply pressurized fuel to the fuel injectors so that the fuel can be easily injected. This pressure helps to atomize the fuel at the tip of the fuel injection valve, which is ejected as a fuel spray. The IC engine operating state and riding conditions measured by the various sensors are stored in a memory block of the ECU called a map. The ECU is programmed with certain preset patterns and fuel delivery amounts when the value reaches a certain amount, and the ECU determines how much fuel to deliver based on these amounts. The various sensors are a throttle position sensor, an idle sensor, a crankshaft rotational speed sensor, and the like.

Generally, in order to improve fuel efficiency and obtain effective combustion characteristics in the combustion chamber, the movement of the air-fuel mixture inlet in the combustion chamber plays an important role, and the combustion characteristics are affected depending on the type of the air-fuel mixture inlet. The type and direction of the air fuel mixture inlet depends on the contour and geometry of the inlet port. It is desirable to obtain a swirling motion of the air-fuel mixture in a lower engine speed range and to obtain a tumble motion of the air-fuel mixture at a higher engine speed. It is further desirable that the inlet motion of the air-fuel mixture has a combined swirl and tumble motion, whereby the IC engine is able to have the combined advantages of swirl and tumble motion over all engine speed ranges. A single port cannot achieve the swirling motion and the tumble motion of the air-fuel mixture. Thus, two intake port cylinder heads for IC engines are known in the art, wherein two different intake ports impart swirl and tumble motions to the auxiliary air fuel mixture in each intake port. The port geometry (direction and curvature) determines the direction of the air-fuel mixture into the combustion chamber. The swirl port opening is located at the center of the cylinder head bore and the tumble port opening is offset from the center of the cylinder bore, with one port located above the other.

There are many intake systems designed to supply an air-fuel mixture to an IC engine having two intake ports (a swirl port and a tumble port). One such design involves the use of separate intake pipes connecting the throttle body to the two intake ports. The intake pipe has a partition wall that divides the path of the flowing air into two separate paths that can supply smooth and non-turbulent flows of air and fuel to the two intake ports. In this regard, the controlled burn rate concept is also used. Controlled burn rate is a port deactivation concept in which turbulent kinetic energy of the air-fuel mixture is generated at the correct time and location in the combustion chamber and rapid and stable combustion occurs, which allows operation of the engine with Lambda excess air ratios well above 1.5. This provides low exhaust emissions and good fuel economy. Two different intake ports, a swirl port and a tumble port, are used to achieve a controlled rate of combustion. Additionally, the throttle body is used for port deactivation. At part load and lower engine speeds, the tumble port is disconnected and only the swirl port is activated. Further, due to the optimum position of the ignition plug, lean combustion with no difference in performance and fuel economy can be obtained.

Therefore, during part-load operation, the butterfly valve in the throttle body is designed to allow only the air-fuel mixture to pass through one path in the intake pipe to supply only the air-fuel mixture to the swirl port. During full valve operation, the air fuel mixture is allowed to enter both paths. In this way, efficient operation over all throttle position ranges may be achieved. However, achieving fuel injection is critical to achieving optimal air velocity, providing fuel spray to both paths of the intake pipe, and additionally ensuring that fuel is injected as close to the intake ports as possible, and the fuel injection path in each intake port should minimize wall wetting. The fuel injection system for such a cylinder head is challenging, difficult to install, poorly accessible and difficult to accommodate in existing vehicle layouts.

Further, in a cylinder head having three ports (two intake ports and one outlet port), a center spark plug is generally used. However, in the partial throttle condition, the air-fuel mixture enters from only one port (swirl port) and therefore combustion occurs only on one side, while there is post-combustion on the tumble port side. This can produce undesirable engine noise. Therefore, to ensure adequate charge distribution, it is desirable to allow some air-fuel mixture to pass through the tumble port.

Therefore, in order to implement a fuel injection system in such a two-wheeled vehicle, various types of fuel injection valve mounts have been proposed in the art. Generally, one solution is to provide two fuel injection valves to direct the air-fuel mixture into two different intake ports. This design has the disadvantages of using additional fuel injection valves, increasing the complexity of the mechanism and using different ECU maps to control the two fuel injection valves, and increasing the capacity of the fuel pump. Replacing two fuel injection valves with a single fuel injection valve is difficult due to the inherent disadvantages of effectively providing fuel spray to two intake ports. Vehicle layout limitations due to space limitations in various frame designs and vehicle layouts make mounting and positioning fuel injection valves and throttle body in two-wheeled vehicles such as described in the preceding paragraph a challenging task.

Thus, to avoid the problems associated with the intake ports of the above-described design, the present invention discloses an intake path equipped with a short-circuited area by removing a small portion of the separating wall that separates the valves in the fuel-air intake passage itself before separating them. Furthermore, the intake pipe is designed to accommodate a fuel injection valve positioned to inject fuel. This allows proportional direct injection of fuel into each of the two intake ports. At the entrance of each port, the charge mixes effectively and produces a uniform charge distribution. Additionally, even during partial throttle operation, the air-fuel mixture enters the swirl ports and tumble ports. It therefore has the dual function of initiating combustion as early as possible and helping to reduce noise when fuel injection is employed. The described invention relates to adapting a fuel injection system to an intake pipe in a split intake pipe design. Second, the short circuiting of the other individual flows helps to supply sufficient fuel to the tumble port, which is generally not operable during a part-throttle condition. This ensures an almost uniform charge in the cylinder. Furthermore, this ensures a sufficient charge flow near the center spark plug tip. This facilitates earlier, faster and more complete combustion, thereby reducing the chance of knock, and facilitates leaner combustion by allowing further spark progression.

By the above design changes, advantages may be obtained such as taking advantage of improved performance of the fuel injection system, minimizing fuel wall wetting in the intake port while injecting fuel, improved IC engine performance, better fuel efficiency and less exhaust emissions. Additionally, minimal layout changes are required to accommodate the fuel injection valve and the throttle body. Further, the fuel pressure loss of the fuel injection valve is minimized. Further, the fuel injection valve and the throttle body are easier to maintain and access, and allow for easy tool movement, and access to the connecting member (such as a fastener). Further, two types of fuel injection valves may be used. In this embodiment, a single fuel spray is injected from a fuel injection valve that is separated by a wall of the cylinder head. In another embodiment, a dual injection type fuel injection valve may be used that injects fuel at two different angles in different directions.

The present subject matter and all of the attendant embodiments, as well as other advantages, are described in more detail in the following paragraphs, which are incorporated in the accompanying drawings.

Fig. 1 shows a two-wheeled vehicle according to one embodiment of the invention. The vehicle includes a frame assembly, typically a chassis frame, that provides a generally open central area to allow a rider to step onto the vehicle. Typically, the frame assembly includes a head tube (102), a main tube (107), and a pair of side tubes 109 (only one shown). The two-wheeled vehicle extends from a front portion (F) to a rear portion (R) on a longitudinal axis. The head pipe (102) is disposed toward the front (F). The main tube (107) extends downward and rearward from the head tube (102) to form a flat horizontal stride portion (117). The other end of the main tube (107) is connected to a pair of side tubes (109) by a bracket (not shown). The head tube (102) is configured to rotatably support a steer tube (104) and is further connected to a front suspension system (121) at a lower end. A handle support member (not shown) is connected to the upper end of the steering tube (102) and supports the handle assembly (106). Two telescoping front suspension systems 121 (only one shown) are attached to a bracket (not shown) on the lower portion of the steer tube (104) on which the front wheels (119) are supported. The upper part of the front wheel (119) is covered by a front fender (103) mounted on the lower part of the steering shaft (104). The pair of side pipes (109) extend from the other end of the main pipe, and are disposed in parallel on both sides in the vehicle width direction. Each of the side pipes (109) includes a down frame portion (109a), and the down frame portion (109a) is inclined and extended from the main pipe (109) and gradually extended rearward in a substantially horizontal direction to the rear of the vehicle after a certain length. A plurality of cross tubes (not shown) are secured between the pair of side tubes (109) at selected intervals to support vehicle accessories, including a tool box (not shown), a seat assembly (108), and a fuel tank assembly (not shown).

The seat (108) is supported on a pair of side tubes (109), and a rider can sit on the pair of side tubes (109). Generally, a toolbox (not shown) is supported between the front portions of the left and right ends of a pair of side pipes (109) so as to be disposed under the seat (108). A fuel tank assembly (not shown) is disposed between the rear portions of the pair of side pipes (109). Front brakes (not shown) and rear brakes (114) are disposed on the front wheels (119) and the rear wheels (113), respectively. The rear wheel (113) is supported toward the rear side of the frame by an Internal Combustion (IC) engine (101), and the Internal Combustion (IC) engine (101) is horizontally swingably coupled to the rear of the frame assembly of the two-wheeled vehicle through a rear suspension system (not shown). When the IC engine is directly coupled to the rear wheels (113) through a Continuously Variable Transmission (CVT) system, the IC engine directly transmits drive to the rear wheels (113). The IC engine includes a CVT system provided on the left side of the IC engine (101) in the vehicle width direction.

Fig. 2 shows a side view of a rear portion of a two-wheeled vehicle showing an IC engine swingably supported to a pair of side pipes (109) according to an embodiment of the present subject matter. Further, FIG. 2 shows an air induction system that supplies an air fuel mixture to an IC engine. The air induction system includes an air cleaner (201), an air cleaner passage (202), a throttle body (302), an intake pipe (601), and a fuel injection valve (301). The air cleaner (201) is located on a rear portion (R) of the two-wheeled vehicle above the rear wheel (113), and the direction of the air flow is from the rear portion to the front portion of the two-wheeled vehicle. The throttle valve body (302) is favorably disposed in a space formed below the storage box and above a crankcase of the IC engine (101). An air filter passage (202) connects an air filter (201) outlet to the throttle body (302). The entire device is assembled to be easily accessible for assembly and disassembly, as it allows the tool to be moved to access the clip secured by the screwdriver once the tool box is removed. An intake pipe (204) connects the throttle body (302) to a cylinder head (not shown). The fuel injection valve (301) is suitably arranged on the intake pipe (601), and this mounting of the fuel injection valve (201) is an important aspect of the present subject matter.

Fig. 3 shows a cross-sectional view of the IC engine (101), showing the main components of the IC engine (101), and representatively showing the fuel inlet of the fuel injection system according to an embodiment of the present subject matter. The IC engine (101) includes a cylinder block (205), and a cylinder head (204) is provided on the cylinder block (205) to form a combustion chamber (306) at the junction. The air-fuel mixture is combusted in a combustion chamber (306), which causes pistons (not shown) to reciprocate within the cylinder block (205) and transfer mechanical energy to a rotatable crankshaft (not shown) that generates power as a result of a slipper crank mechanism. The cylinder head (204) includes two intake valves, a swirl intake valve (308) and a tumble intake valve (not shown) operating in a swirl port (501) and a tumble port (502). The valves are operated by rocker arms (310) actuated by camshafts (309). Typically, the swirl intake valve (308) and the tumble intake valve are actuated by a single rocker arm. A cam chain (not shown) operatively connects a rotatable crankshaft (not shown) and a camshaft (309) to drive it in the cylinder head (204). Atmospheric air from the throttle valve body (302) and fuel injected through the fuel injection valve (301) enter the swirl port (501) and the tumble port (502), respectively. The cylinder head (204) also includes an exhaust port (307), the end of which facing the combustion chamber (306) is controlled by an exhaust valve (not shown), and the exhaust port (307) directs exhaust gas out of the combustion chamber (306) to a muffler (111) connected to the exterior of the cylinder head (204). In an embodiment of the present invention, the engine operates in four cycles, i.e., an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. Combustion of the air-fuel mixture occurs at the end of the compression stroke and the beginning of the power stroke. After combustion, exhaust gas is generated, which exits the cylinder block (204) during the exhaust stroke.

In an exemplary embodiment, the throttle body (302) includes a throttle housing (not shown), an idle air control valve (302b), a throttle position sensor, and a throttle control system. The throttle housing includes a housing having a venturi for throttling inlet atmospheric air under pressure to the IC engine (101). A butterfly valve (not shown) is arranged downstream of the venturi, which is rotatable about an axis. Controlling the rotation may control air control towards the first path (602) or both the first path (602) and the second path (603). The idle air control valve (302b) includes an electronic actuator and a separate idle airflow circuit for controlling and maintaining an idle state of the IC engine (101). A throttle position sensor (operating on the hall effect principle in an exemplary embodiment) can detect a real-time status of the throttle position and transmit a signal to a control unit (not shown).

FIG. 4 shows an exploded view of a cylinder head, intake air conduit, and fuel injection system according to an embodiment of the present subject matter. The intake pipe (601) is placed on a cylinder head intake mounting surface (204a) of the cylinder head (204). An insulating gasket (304) is placed between the intake pipe (601) and the cylinder head intake mounting surface (204 a). The insulating mat (304) acts as a flame arrestor, preventing the transfer of flame and heat from the combustion chamber (306) back to the intake pipe (601). The intake pipe (601) includes a port flange (608) having a threaded hole (608 a). The port flange (608) has a profile that matches a surface of the cylinder head intake mounting face (204a) when assembled, and the threaded holes (608a) match corresponding threaded holes on the insulating mat (304) and the cylinder head intake mounting face (204a) into which fasteners may be inserted.

Fig. 5 illustrates a side view of a cylinder head (204) according to an embodiment of the present subject matter. The cylinder head (204) includes a cylinder head intake mounting surface (204a) on a side facing the roof of the two-wheeled vehicle, a surface of which is capable of receiving an intake pipe (601). The cylinder head (204) includes two intake ports, a swirl port (501) and a tumble port (502), which control the flow of an air-fuel mixture into the combustion chamber (306), and whose opening is defined in the cylinder head intake mounting face (204 a). The tumble port (502) opening is offset from the swirl port (501) opening and is disposed above the swirl port (501) opening. The swirl port (501) extends parallel to the tumble port (502) to the combustion chamber (306). The swirl port (501) and tumble port (502) openings have an elliptical shape, while the outlet at the combustion chamber (306) is circular. The elliptical shape increases the surface area of the port opening to allow for more air and fuel to enter while occupying less space on the cylinder head intake mounting face (204 a). The swirl port (501) is designed to have a profile with a greater curvature than the profile of the tumble port (502), but the swirl port (501) has a lower inclination towards the valve axis.

Fig. 6a shows a front isometric view, fig. 6b shows a side isometric view, fig. 6c shows a front view, and fig. 7 shows a cross-sectional view of an air inlet tube (601) according to an embodiment of the invention. The short circuit pocket as described in the present invention is located in the curved portion of the inlet pipe so that larger fuel droplets due to centrifugal action enter the tumble port and cause the swirl port to flow leaner than usual and without larger droplets. This helps to reduce fuel loss due to fuel sticking to the cylinder wall and helps to scrape fuel to the oil sump by the oil control ring on the piston, while the charge inside the cylinder is undergoing swirling motion. Such shorted cylinders may also reduce carbon monoxide and NOx emissions, knock, fuel loss, oil dilution. Although the tumble port flow (which would otherwise not flow during partial throttling) will carry the recall fuel and burn completely to produce better combustion. The invention is also applicable to the case where the inlet duct is straight. There will be no centrifugal effect in an IC engine (101) with a straight intake pipe, but there is also a significant improvement in tumble action. The short-circuit pocket created is just enough to allow a small charge to pass through the tumble port (502) and remain through the swirl port (501) during a partial throttle condition. This helps achieve better low end torque and improves combustion efficiency, since sufficient turbulence is generated within the combustion chamber (306).

The swirl port (501) generates a swirling motion in the charge as the charge enters the combustion chamber (306) from the first path (602) of the intake pipe (601). The tumble port (502) generates a tumble motion in the charge when the charge enters the combustion chamber (306) from the second path (603) of the intake pipe (601). Air from the throttle body (302) is split as the flow exits the throttle body (302) and enters the intake pipe (601). Then, due to the dividing wall (604), the air is kept in separate flows until they are mixed within the combustion chamber (306) (except for a separate mixing area (620) in the dividing wall (604) on the intake pipe (601)). During a part-throttle condition, contact between the butterfly valve in the throttle body (302) and the partition wall (604) ensures that there is no charge flow in the second path (603) of the intake pipe (601). After the throttle position rises beyond the dividing wall (604), the charge is allowed to enter the second path (603). This effectively ensures that only the swirl port (501) is operable during a partial throttle condition and that both ports are operable during higher and full throttle positions.

The shorting pockets provide a bypass between the two streams, which may not be completely mutually exclusive. Near the interface of the intake pipe and the cylinder head intake mounting face (204a), the port end (610) of the intake pipe is provided with a cutout/passage in its partition wall. This allows the charge to be diverted from the first path (602) to the second path (603), especially during a down-throttle operation. The spark plug (305) is mounted on the cylinder head (204) such that the tip of the spark plug is located at the center of the combustion chamber (306). Otherwise, without a bypass cut, there must be two spark plugs offset in the direction opposite the center. During a lower throttle condition, charge enters the cylinder through the bottom swirl port (501). Due to the short-circuited area, some amount of charge also enters through the tumble port (502). Charge flow from the tumble port (502) reaches the center spark plug more easily than a rotating charge. This ensures that combustion starts early, flame propagation is faster, and combustion is more complete, since the air-fuel mixture is more homogeneous. Further, this makes it possible to advance the ignition timing without knocking and lean burn, thereby having lower Brake Specific Fuel Consumption (BSFC) and the like.

The short circuit portion forming the mixing region (620) facilitates the position of the fuel injection valve in which the fuel spray is injected into the mixing region (620) toward the swirl port (501) and the tumble port (502). To facilitate mounting of the fuel injection valve (301), the intake pipe (601) is provided with an injector region (605), the injector region (605) having a mounting flange and an opening allowing entry of the fuel injection valve (301). The mixing region (620) of the air intake pipe (601) is suitably dimensioned such that the ratio of the vertical distance (D) from the end of the air intake pipe (601) to the tip of the partition wall (604) in the mixing region (620) to the cross-sectional width of any one of the two air intake ports E and F (501 and 502) is between 1.5 and 3.

Fig. 3 and 7 illustrate fuel injection paths taken when a fuel injector is disposed in an intake pipe (601) to direct fuel in embodiments of the present subject matter. In the layout of the present engine, the IC engine is inclined such that its cylinder bore axis is inclined at an angle of between 0 ° and 15 ° with respect to the horizontal. The swirl port (501) and the tumble port (502) face upward of the two-wheeled vehicle. The intake pipe (601) is designed to be able to position and mount the fuel injection valve (301) and is one of the important aspects of the present subject matter. The fuel injection valve (301) is mounted at an angle of a predetermined angle (theta) to the horizontal plane Y-Y to achieve fuel injection targets on the swirl port (501) and the tumble port (502). In one embodiment, the fuel injection valve (301) is disposed at a predetermined angle (θ) between 75 ° and 88 ° from a horizontal axis (Y-Y) of the vehicle. The fuel injection valve (301) is of a single fuel injection type, which can inject fuel spray in one angular direction. In one embodiment, the injection angle is in the range of 8 ° to 15 ° from the fuel tip.

Further, the injector tip (P) is disposed at a predetermined vertical distance (a) from the cylinder head intake mounting face (204a) such that a ratio of the vertical distance (a) between the tip and the port end (608) of the fuel injection valve (301) to the cross-sectional width E & F of any one of the two intake ports (501 and 502) is between 2.5 and 3, and the extension of the fuel injector axis (X-X) does not intersect the partition wall (604). This ratio helps direct the fuel injection to the port end (608) to efficiently and in a desired manner enter the swirl port (501) and tumble port (502). The fuel injection valve is positioned on the intake pipe (204) such that the fuel injection is optimized such that the fuel injection target is located on the sharp-edged element (304a) of the insulating mat (304) to separate the fuel spray cone (606) from the fuel injection valve (301) to be entered into the swirl port (501) and the tumble port (502). The fuel injection valve (301) is also mounted on the end of the curved portion (621) of the intake pipe (601) so that with minimal wall wetting, the fuel spray travels the shortest distance to reach the outlets of the swirl port (501) and tumble port (502). The intake pipe (601) has a non-linear curved profile and is divided into a curved portion (621) and a straight portion (622), and wherein the curved portion extends from the port end (608) to the tip end of the fuel injection valve (301), and the substantially straight portion (622) extends from the tip end of the fuel injection valve (301) to the throttle end (607). The intake pipe (601) has a partition wall (604), the partition wall (604) being arranged such that a width (B) of the first path (602) at the throttle end (607) is greater than a width (a) of the first path (602) at the port end (608), and wherein a width (H) of the second path (603) at the throttle end (607) is less than or equal to a width (G) of the second path (603) at the port end (608), wherein the partition wall (604) is more biased toward the first path (602) than the second path (603).

Many modifications and variations of the present subject matter are possible in light of the above disclosure. Therefore, within the scope of the claims of the present subject matter, the disclosure may be practiced other than as specifically described.

Claims

1. An Internal Combustion (IC) engine (101), the Internal Combustion (IC) engine (101) comprising:

a cylinder head (204);

the cylinder head (204) comprises two intake ports (501, 502) separated by a cylinder partition wall (503), and the two intake ports (501, 502) are configured to direct an air-fuel mixture into the Internal Combustion (IC) engine (101);

an air cleaner (201) disposed behind the Internal Combustion (IC) engine (101);

an intake system connecting the air cleaner (201) and the two intake ports (501, 502), the intake system comprising:

a throttle valve body (302) configured to control a flow rate of air drawn from the air cleaner (201); an air cleaner passage (202) connecting the air cleaner (201) and the throttle valve body (302);

an intake pipe (601) provided downstream of the throttle body (302) connecting the throttle body (302) to the two intake ports (501, 502); the intake pipe (601) has a non-linear curved profile with a throttle body end (607) and a port end (608); the intake pipe (601) includes a partition wall (604) that divides the intake pipe (601) into a first path (602) and a second path (603); and is

The throttle body end (607) of the intake pipe (601) is connected to the throttle body (302), and the port end (608) of the intake pipe (601) is connected to the cylinder head (204), whereby the partition wall (604) and the cylinder head partition wall (503) of the intake pipe (601) are connected in series,

the method is characterized in that:

the first path (602) and the second path (603) supply each of the two intake ports (501, 502) on the cylinder head (204) with an air-fuel mixture, respectively, and the intake pipe (601) is provided with a mixing region (620) through at least one cutout provided in a partition wall (604);

-said inlet pipe (601) having a fuel injection valve (301) mounted on the inlet pipe (601) along a fuel injector axis (X-X), said fuel injection valve (301) being configured to direct fuel to said two inlet ports (501, 502) through said mixing region (620); and is

The fuel injection valve (301) is mounted such that the ratio of the vertical distance (a) between the fuel injection point (P) and the base (Y-Y) of the port end to the cross-sectional width (E, F) of at least one of the two intake ports (501, 502) is between 1.5 and 3.

2. The Internal Combustion (IC) engine (101) of claim 1, wherein the fuel injection valve (301) is mounted with a fuel injector axis (X-X) at a predetermined acute angle (θ) relative to a base (Y-Y) of the port end, and wherein the fuel injector axis (X-X) does not intersect the dividing wall (604).

3. An Internal Combustion (IC) engine (101) as in claim 1 wherein a width (B) of the first path (602) at the throttle body end (607) is greater than a width (a) of the first path (602) at the port end (608), and wherein a width (H) of the second path (603) at the throttle body end (607) is less than or equal to a width (G) of the second path (603) at the port end (608), whereby the separation wall (604) is more biased toward the first path (602) than the second path (603).

4. An Internal Combustion (IC) engine (101) as claimed in claim 1 or 3 wherein the fuel injection valve (301) is oriented to provide a fuel injection angle from the tip of the fuel injection valve (301) in the range of 8 ° to 15 °.

5. The Internal Combustion (IC) engine (101) of claim 1, wherein a ratio of a vertical distance (D) from an end of the intake pipe (601) to a tip of the partition wall (604) in a mixing region (620) to a cross-sectional width E or F of any one of the two intake ports (501, 502) is between 1.5 and 3.

6. The Internal Combustion (IC) engine (101) of claim 1, wherein the intake pipe (601) has a non-linear curved profile and is divided into a curved portion (621) and a straight portion (622), and wherein the curved portion extends from the port end (608) to a tip end of the fuel injection valve (301), and a substantially straight portion (622) extends from the tip end of the fuel injection valve (301) to the throttle body end (607).

7. An Internal Combustion (IC) engine (101) as claimed in claim 1 wherein an insulating gasket (304) is provided between the intake pipe (601) and the cylinder head (204), the insulating gasket (304) having an element (304a) to separate a fuel spray cone (606) from fuel injection valves (301) into both intake ports (501, 502).

8. The Internal Combustion (IC) engine (101) of claim 1, wherein the two intake ports comprise a swirl intake pipe that directs the air-fuel mixture to the swirl intake port and a charge intake pipe that directs the air-fuel mixture to the charge intake port.

9. The Internal Combustion (IC) engine (101) of claim 2, wherein the predetermined acute angle (Θ) is between 75 and 88 degrees.

10. A vehicle having an internal combustion engine (101) as claimed in claim 1.