JP4670996B1 - Engine intake system passage structure - Google Patents

Abstract

An intake system passage structure for an engine that realizes appropriate piping while being compact is provided.
An air cleaner 15 disposed above a crankcase 13, a carburetor 18 connected to an intake passage led to the front of the air cleaner 15, and an intake pipe connecting the carburetor 18 and an intake port of a cylinder head 13B. The intake system passage structure of the engine 19 includes a breather hose 23 that is led to the front of the air cleaner 15 and connected to the cylinder head cover 12A. The breather hose 23 is piped so as to pass above the throttle position sensor 22 in a side view and always descend toward the cylinder head.
[Selection] Figure 3

Description

  The present invention relates to a structure of an intake system passage of an engine in a vehicle such as a motorcycle.

  In gasoline engines, etc., so-called blow-by gas causes engine oil deterioration, metal corrosion, and air pollution, so it is returned to the intake side, mixed with a new mixture, and burned. In order not to release into the atmosphere.

  For example, in an engine described in Patent Document 1 or the like, a breather case is provided in a cylinder head cover, and blow-by gas is supplied from the breather inlet penetrating the cylinder head cover to an oil separation chamber in the breather case and a breather outlet to the intake system of the engine. It is configured to be introduced.

  Further, in a vehicle such as a scooter type motorcycle, there is an engine in which an air cleaner is disposed above a crankcase and an intake passage extends straight forward in front of the air cleaner. And when a breather chamber is provided in a cylinder head cover and it opens to an air cleaner, a breather hose which connects both is required. In order to return the breather oil in the hose to the engine, the breather hose is preferably piped so that the air cleaner is opened higher than the breather chamber so as not to form a valley in the hose routing section.

JP-A-10-220215

  However, when piping the breather hose, it may intersect with other members (for example, secondary air hose and adjacent parts), and in order to secure a gap at the intersection, May be. In particular, in a scooter type vehicle or the like having a swing type engine (power unit), consideration must be given so that interference with each component does not occur when mounted on a compact vehicle. For this reason, by setting the bending points at a large number of locations on the breather hose, it is necessary to take measures such as avoiding interference with other parts, resulting in an increase in cost.

  In view of such circumstances, an object of the present invention is to provide an intake system passage structure for an engine that realizes an appropriate piping while being compact.

  The intake system passage structure of the engine of the present invention includes a cylinder inclined substantially horizontally toward the front, and is connected to an air cleaner disposed above the crankcase and an intake passage led to the front of the air cleaner. In an intake system passage structure of an engine including a carburetor and an intake pipe that connects the carburetor and an intake port of a cylinder head, the engine has a breather hose led to the front of the air cleaner and connected to a cylinder head cover. It is characterized in that piping is provided so as to pass above the throttle position sensor in a side view and always descend toward the cylinder head.

Further, in the intake system passage structure of the engine of the present invention, the breather hose is piped substantially linearly in both side view and top view and substantially parallel to the intake passage.
Further, in the intake system passage structure of the engine of the present invention, the secondary air hose connecting the secondary air cut valve and the air cleaner is piped through the lower part of the throttle position sensor in a side view. Features.
In the intake system passage structure for an engine according to the present invention, a concave portion is provided at a corner of the top surface of the cylinder head cover, and the breather hose is connected to the concave portion.

  According to the present invention, the breather hose piped so as to always descend can return the oil content contained in the blow-by gas to the breather chamber properly and smoothly, effectively reducing oil consumption and preventing deterioration of combustion. Can do. Moreover, the number of hose bending locations can be effectively reduced during piping. In this case, it is possible to separate the housing from the secondary air hose and to achieve a compact size.

1 is a side view showing an overall configuration of a motorcycle according to the present invention. 1 is a perspective view showing a configuration example of a body frame of a motorcycle according to the present invention. FIG. 3 is a side view showing a configuration example of a power unit mounted on a vehicle body frame in the motorcycle according to the present invention. 1 is a front view of a power unit in a motorcycle according to the present invention. FIG. 3 is a top view of a power unit in the motorcycle according to the present invention. FIG. 3 is a perspective view of a main part of the intake system passage structure in the motorcycle according to the present invention. FIG. 2 is a side view of the main part of the intake system passage structure in the motorcycle according to the present invention. FIG. 2 is a top view of the main part of the intake system passage structure in the motorcycle according to the present invention.

A preferred embodiment of an intake system passage structure for an engine according to the present invention will be described below with reference to the drawings.
FIG. 1 is a side view of a motorcycle according to the present invention. First, the overall configuration of the motorcycle will be described with reference to FIG. In the drawings used in the following description including FIG. 1, the front of the vehicle is indicated by an arrow Fr, the rear of the vehicle is indicated by an arrow Rr, and the side right side of the vehicle is indicated by an arrow R as necessary. The left side is indicated by an arrow L.

  The vehicle 100 is configured by forming a vehicle body skeleton by a plurality of vehicle body frames made of steel or aluminum alloy and mounting various parts on the vehicle body frame. Note that FIG. 2 is also referred to as an example of the configuration of the body frame. The down tube 101 which is a part of the body frame has a front end coupled to the steering head pipe 102 and extends substantially downward from the steering head pipe 102, and is connected to the under frame 103 near the lower end portion thereof. The under frame 103 extends substantially rearward. A rear frame 104 composed of a pair of left and right as a part of the vehicle body frame is coupled to the rear side of the down tube 101, and each of them extends generally inclining rearward and upward.

  The steering head pipe 102 rotatably supports a front fork 105. A handle bar 106 is fixed to the upper end of the front fork 105, and a front wheel 107 is rotatably supported on the lower end side. The front wheel 107 is equipped with a brake disc 108 that rotates integrally therewith.

  Further, referring also to FIG. 3, a bracket 109 for supporting the power unit 10 including the engine 11 is attached to the rear end of the under frame 103, and a swing shaft is provided via a stay 110 provided on the bracket 109. A swing type power unit 10 is supported around 111 so as to be swingable in the vertical direction. The power unit 10 is a unitization of a transmission assembly 14 that includes a cylinder assembly 12 of an engine 11, a crankcase 13, and a continuously variable transmission using a belt / pulley. The rear wheel 112 is rotatably supported by the transmission device 14 on the vehicle rear side. The axle side of the rear wheel 112 and the rear frame 104 are connected by a shock absorber 113, and the power unit 10 as a whole functions as a swing arm.

  Further, as shown in FIG. 1, a seat 114 for a rider to sit on is installed above the power unit 10, and a step board 115 on which the rider seated on the seat 114 places his feet above the underframe 103, It is supported by a step frame 116 (see FIG. 2). The step board 115 is formed integrally with a leg frame cover that constitutes the exterior of the vehicle. Further, between the power unit 10 and the seat 114, there is a luggage box 117 formed as a storage space for articles and the like opened and closed by the seat 114.

  As a vehicle exterior, various vehicle body covers are supported and attached to appropriate positions such as a vehicle body frame. The front leg shield 118 covers the front side of the vehicle and is mounted with a winker or the like, and is continuous with the above-described step board 115. The rear frame cover 119 covers the lower part of the seat 114 or the rear side of the vehicle, and a winker and a brake lamp are mounted. Upper portions of the front wheel 107 and the rear wheel 112 are covered with a front fender 120 and a rear fender 121, respectively.

  Next, the power unit 10 will be further described with reference to FIGS. In the power unit 10, particularly in the intake system thereof, an air cleaner 15 is mounted on the upper surface side of the transmission 14 located on the vehicle rear side. The air cleaner 15 generally has a deformed box shape, and an air intake pipe 16 extends from the vicinity of the left front part, and an intake hose 17, a carburetor 18 and an intake pipe (intake pipe) 19 are connected sequentially from the front part toward the right side in front of the air cleaner 15. Is done. Here, the cylinder assembly 12 is formed by sequentially connecting a cylinder head cover 12A, a cylinder head 12B, and a cylinder 12C. The intake pipe 19 communicates with an intake port (intake port) in the cylinder head 12B of the cylinder assembly 12, and is cleaned from the air cleaner 15 to the intake port of the cylinder head 12B through an intake passage constituted by these members. Air is supplied. In addition, although detailed illustration is abbreviate | omitted, the fuel injection apparatus is standingly arranged by the intake pipe 19, and a fuel is injected toward an intake port. Further, an exhaust port is formed on the lower surface side of the cylinder assembly 12, and the exhaust pipe extends from the exhaust port to extend rearwardly and is connected to a muffler at the rear of the vehicle.

  As described above, the power unit 10 includes the cylinder assembly 12, the crankcase 13, and the transmission device 14, and these are integrated. With the power unit 10 mounted on the vehicle 100, the cylinder assembly 12, the crankcase 13, and the transmission device 14 are arranged in this order from the vehicle front side. The cylinder assembly 12 includes a single-cylinder air-cooled engine, and is arranged so that the cylinder axis is substantially horizontal along the vehicle longitudinal direction.

  As described above, an intake passage composed of the intake hose 17, the carburetor 18, and the intake pipe 19 is formed from the air cleaner 15 toward the front side at an appropriate interval above the power unit 10 (cylinder assembly 12). The passage is arranged linearly so as to substantially follow the cylinder axis in plan view (FIG. 5). In this case, the carburetor 18 is connected to the intake pipe 19 in a substantially horizontal state, and the intake pipe 19 is disposed at a substantially central portion in the left-right direction of the cylinder with an appropriate gap above the cylinder head 12B. Further, the intake pipe 19 is connected to an intake port on the cylinder head 12B side in such a manner that the front side thereof is bent downward.

  With further reference to FIGS. 6 to 8, the intake system surroundings in the power unit 10 will be described. First of all, an intake passage (a part) is formed through the carburetor 18, and a throttle valve is supported in the intake passage so as to be rotatable about its rotation axis. It is assumed that the amount of air discharged to the downstream side is controlled by changing the opening of the intake passage according to the rotation angle of the throttle valve.

  As shown in FIG. 8 and the like, a throttle pulley 20 coupled to the rotation shaft of the throttle valve is disposed outside the carburetor 18 (right side in this example). A throttle cable is connected to the throttle pulley 20. For example, the throttle pulley 20 can be rotationally driven through the throttle cable by operating an accelerator handle or the like provided on the handle bar 106, that is, the throttle valve can be controlled to open and close. The throttle pulley 20 is urged in the return direction by the elasticity of the return spring 21 (see FIG. 8 and the like), and automatically returns. Further, a throttle position sensor 22 which is a throttle opening detection device is mounted on the outer side of the carburetor 18 opposite to the throttle pulley 20. The throttle position sensor 22 may be configured using, for example, a rotary encoder.

  Further, the breather hose 23 connects between the cylinder head cover 12A and the air cleaner 15. In this case, the breather hose 23 is led to the front of the air cleaner 15 and connected to the cylinder head cover 12A. However, when viewed from the left side of the carburetor 18 (see FIG. 7 and the like), the breather hose 23 always passes above the throttle position sensor 22 Piping to descend toward Further, as shown in FIG. 8, it is piped substantially in parallel with an intake passage composed of the intake hose 17, the carburetor 18, and the intake pipe 19 in a plan view. Further, a recess 24 is provided at the upper left corner of the top surface of the cylinder head cover 12A, and a connection union 25 is provided on the side wall 24a of the recess 24 so that the breather hose 23 is connected to the union 25 from the left side. I have to. A breather chamber is provided on the inner side of the cylinder head cover 12A corresponding to the portion where the connection union 25 is provided.

  The cylinder head cover 12A and the air cleaner 15 are also connected by a secondary air hose 26. In this case, a secondary air cut valve 27 is disposed in the middle of the secondary air hose 26. The secondary air hose 26A that connects between the secondary air cut valve 27 and the air cleaner 15 passes below the throttle position sensor 22 in a side view (see FIG. 7 and the like) on the left side of the carburetor 18 and is concavely curved upward. Piping. Thus, both the breather hose 23 and the secondary air hose 26 (secondary air hose 26A) are piped on the left side of the carburetor 18, that is, not arranged on the right side where the throttle pulley 20 which is a movable member is arranged.

  Note that the front side of the secondary air hose 26 is connected to a connection portion 28 provided on the top surface of the cylinder head cover 12A in such a manner as to bend downward from the secondary air cut valve 27. A mounting bracket 29 fixed to the upper portion of the carburetor 18 extends substantially forward, and the secondary air cut valve 27 is supported and fixed by the mounting bracket 29.

According to the intake system passage structure having the above-described configuration, first, the breather hose 23 is piped from the air cleaner 15 so as to always descend toward the cylinder head 12B as described above, whereby oil contained in the blow-by gas is removed from the breather chamber. Therefore, oil consumption can be reduced and combustion deterioration can be effectively prevented.
In this case, piping is performed above the throttle position sensor 22, but the secondary air hose 26, in particular, the secondary air hose 26 </ b> A is piping below the throttle position sensor 22, so that they can be separated. The space above the throttle position sensor 22 can be used effectively.
Further, since the breather hose 23 is piped so as to be always lowered toward the cylinder head 12B, the breather hose 23 can be piped substantially linearly in both side view and top view, and the number of hose bends can be effectively reduced during the piping. .

  In addition, as described above, the secondary air hose 26A is piped under the throttle position sensor 22 so that they can be separated from each other due to the mutual relationship with the breather hose 23, and the space below the throttle position sensor 22 is effectively utilized. can do. By fixing the secondary air hose 26 to the cylinder head 12B or the cylinder block, the swinging of the secondary air hose 26 during operation can be suppressed, and contact or interference with peripheral parts can be avoided.

  In the above case, a sluttle pulley 20 is provided on one side of the carburetor 18 and a breather hose 23 is piped on the other side substantially parallel to the intake passage. As a result, interference between the movable throttle pulley 20 and the breather hose 23 can be avoided, and proper and safe operation of the member can be ensured. If the breather hose 23 or the like is provided on the throttle pulley 20 side, the breather hose 23 and the like are arranged apart from each other to avoid interference between the two, and the arrangement space must be increased. By arranging it on the opposite side of the movable member such as the throttle pulley 20, it is possible to substantially save space.

Further, by providing the recess 24 on the top surface of the cylinder head cover 12A and connecting the breather hose 23 to the side wall 24a of the recess 24, the width in the left-right direction of the engine can be made compact when viewed from above.
Further, by connecting the breather hose 23 above the throttle position sensor 22 and the secondary air hose 26 below, the interference between the hoses can be reduced. It becomes possible to do.

  By making the pipes including the breather hose 23 and the secondary air hose 26 compact, the power unit 10 as a whole can be made compact. In particular, in the swing type power unit 10 as in this example, it swings in the vertical direction. By making the circumference of the pipe compact, troubles due to interference with peripheral members such as the rear frame 104 and the luggage box 117 can be effectively and prevented in advance.

  In addition, by reducing the size of the hose piping and clarifying the segregation of each hose in this way, the contact between the hoses can be reduced, and the overall length of the hose can be substantially shortened. It can be effectively reduced, and as a result, there are advantages such as cost reduction or reduction of bending jigs and bending processes thereof.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
For example, although the example which connects the breather hose 23 from the left side with respect to the connection union 25 of the recessed part 24 was demonstrated, according to arrangement | positioning of the union 25, it can connect from other than the left side.

10 power unit, 11 engine, 12 cylinder assembly, 13 crankcase, 14 transmission device, 15 air cleaner, 16 air intake pipe, 17 intake hose, 18 carburetor, 19 intake pipe, 20 throttle pulley, 21 return spring, 22 throttle position sensor , 23 Breather hose, 24 recess, 25 connection union, 26 secondary air hose, 27 secondary air cut valve, 100 vehicle, 101 down tube, 102 steering head pipe, 105 front fork, 106 handlebar, 107 front wheel, 108 brake Disc, 111 swing axis, 113 shock absorber, 114 seat, 115 step board, 118 front leg shield, 11 Rear frame cover, 120 a front fender, 121 rear fender.

Claims (4)

An air cleaner having a cylinder inclined substantially horizontally toward the front, disposed above the crankcase, a carburetor connected to an intake passage led to the front of the air cleaner, and an intake port of the carburetor and the cylinder head In the intake system passage structure of the engine consisting of the intake pipe connecting the
It has a breather hose that is led to the front of the air cleaner and is connected to the cylinder head cover, and the breather hose is routed above the throttle position sensor in a side view and is always piped so as to descend toward the cylinder head. Characteristic engine intake system passage structure.   2. The intake system passage structure of an engine according to claim 1, wherein the breather hose is piped substantially linearly in both side view and top view and substantially parallel to the intake passage. 3.   3. The engine according to claim 1, wherein a secondary air hose connecting a secondary air cut valve and the air cleaner is piped under the throttle position sensor in a side view. 4. Intake system passage structure.   The intake system passage structure for an engine according to any one of claims 1 to 3, wherein a concave portion is provided in a corner portion of the top surface of the cylinder head cover, and the breather hose is connected to the concave portion.

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