JP6003491B2 - Engine cooling structure - Google Patents

Description

  The present invention relates to an engine cooling structure, and more particularly to an engine cooling structure including an air guide member.

  2. Description of the Related Art A motorcycle that employs an engine cooling structure that includes a shroud that covers a cylinder and a cylinder head and a fan for blowing air is known (for example, see Patent Document 1). In this motorcycle, air is guided by a fan for blowing air through a flow path formed by a shroud, and a heated cylinder and a cylinder head are cooled. Since the fan is rotated by the power of the engine and the cylinder and the cylinder head are forcibly cooled, higher cooling efficiency can be obtained compared to natural cooling by running wind.

  In this motorcycle, an injector for controlling the supply of fuel to the combustion chamber is disposed in the vicinity of the cylinder head. When the injector becomes hot due to heat from the cylinder and the cylinder head, the fuel in the injector is vaporized, causing problems such as unstable engine speed and reduced output. Therefore, in the cooling structure described in Patent Document 1, a flow path that guides the air that has passed through the cylinder and the cylinder head to the injector is formed so that the injector is cooled.

JP 2010-223211 A

  However, in the cooling structure described in Patent Document 1, since the air whose temperature has increased through the cylinder and the cylinder head is guided to the injector, the cooling efficiency of the injector may be reduced. In this case, it is difficult to prevent the fuel in the injector from being vaporized.

  The present invention has been made in view of this point, and an object of the present invention is to provide an engine cooling structure capable of appropriately cooling components such as an injector and the like affected by the heat of a cylinder and a cylinder head.

An engine cooling structure according to the present invention includes a wind guide member that covers a part of a cylinder and a cylinder head of an engine, and forms a cooling flow path that guides cooling air to the cylinder and the cylinder head; An engine cooling structure comprising a blower member to be sent to a cooling flow path and a fuel injection device disposed in an intake port of the engine , wherein the engine has the intake port directed upward with respect to an exhaust port disposed toward the longitudinal direction axis of the cylinder to be, the air guide member, have a blocking portion that form the branch flow path of the air is branched to the cooling passage leading to the fuel injection device The branch flow path is guided so that the cooling flow path is sandwiched vertically between the cylinder and the cylinder head at a position away from the cylinder and the cylinder head. Is formed along the inner wall surface of the member, the air blown to the fuel injection device through the branched flow path, characterized in that it is discharged from above the vehicle.

According to this configuration, the air guide member, because it has a shielding portion which forms a branch flow path into the fuel injection device guiding the air, cooling the fuel injection device in a different air from the air for cooling the cylinder and a cylinder head it can. Further, since the branch flow path is formed at a position away from the cylinder and the cylinder head, it is possible to suppress the propagation of heat from the cylinder and the cylinder head to the branch flow path, and to improve the cooling efficiency of the fuel injection device. . Therefore, an engine cooling structure capable of appropriately cooling components affected by the heat of the cylinder and the cylinder head is realized. In addition, since the branch flow path is formed along the inner wall surface of the air guide member so that the cooling flow path is sandwiched between the cylinder and the cylinder head, heat is transmitted from the cylinder and the cylinder head to the branch flow path. Can be further suppressed. Further, since the cooling channel is not blocked by the branch channel, the cooling efficiency of the cylinder and the cylinder head can be maintained high. Further, since the fuel injection device can be appropriately cooled by the air supplied through the branch flow path, the fuel can be stably supplied by preventing the fuel from being vaporized in the fuel injection device.

  In the engine cooling structure of the present invention, it is preferable that the shielding portion branches the cooling flow path at a position before the air from the air blowing member reaches the cylinder and the cylinder head. According to this structure, since the shielding part branches the cooling flow path at a position before the air from the air blowing member reaches the cylinder and the cylinder head, the air flowing through the branch flow path due to the heat of the cylinder and the cylinder head. Temperature rise can be prevented. Therefore, the cooling efficiency of components can be improved.

  In the engine cooling structure according to the aspect of the invention, it is preferable that the shielding portion is formed of a member different from the air guide member. According to this configuration, since the degree of freedom of the shape is increased as compared with the case where the air guide member and the shielding portion are integrally formed, the cooling flow path and the branch flow path are reliably separated from the cylinder and the cylinder head. The propagation of heat to the branch channel can be suppressed. Further, since the material of the air guide member and the material of the shielding part can be changed, the heat insulating effect of the shielding part can be enhanced, and the propagation of heat from the cylinder and the cylinder head to the branch channel can be further suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the engine cooling structure which can cool appropriately components, such as an injector which receives the influence of the heat | fever of a cylinder and a cylinder head, can be provided.

1 is a perspective view showing an appearance of a motorcycle. Fig. 2 is a left side view showing a structure around a rear wheel of a motorcycle. Fig. 3 is a right side view showing a structure around a rear wheel of a motorcycle. It is a perspective view which shows an engine and its surrounding structure. It is sectional drawing which cut | disconnected the engine by the plane perpendicular | vertical to a vehicle width direction. It is explanatory drawing for demonstrating the cooling structure of an engine. It is a perspective view which shows the shape of a shroud. It is a perspective view which shows the structure of a shielding part. It is a schematic diagram which shows the flow of the air in a shroud.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, an example in which the engine cooling structure according to the present invention is applied to a scooter type motorcycle will be described, but the application target is not limited to this and can be changed. For example, the engine cooling structure according to the present invention may be applied to other types of motorcycles, four-wheeled vehicles, and the like.

  The configuration of the motorcycle according to the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing an appearance of a motorcycle according to the present embodiment, FIG. 2 is a left side view showing a structure around a rear wheel of the motorcycle, and FIG. 3 is a rear wheel of the motorcycle. FIG. 4 is a right side view showing the structure of the periphery, and FIG. 4 is a perspective view showing the structure of the engine and its periphery. In each figure used in the following description, the front of the vehicle body is indicated by an arrow F. In the following drawings, some components may be omitted for convenience of explanation.

  As shown in FIGS. 1 to 3, the scooter type motorcycle 1 is configured by attaching various covers as a vehicle body exterior to an underbone frame 11 made of steel or aluminum alloy. A leg shield 21 that protects the driver's legs is provided at the front of the motorcycle 1, and a step board 22 on which the legs are placed is disposed behind the leg shield 21. A side cover 23 that covers the side surface of the vehicle body is provided behind the step board 22.

  A front fork 31 is rotatably supported at the front of the vehicle body via a steering shaft (not shown). A handlebar 32 for steering the front wheel 3 is provided above the front fork 31. A brake lever 33 is provided on the handle bar 32, and a headlamp 34 is disposed in front of the handle bar 32. A front fender 35 that covers the upper part of the front wheel 3 is installed at the lower part of the front fork 31 while the front wheel 3 is rotatably supported. The front wheel 3 is provided with a brake disk (not shown) and a caliper (not shown) that holds the brake disk.

  The seat 5 is disposed above the side cover 23, and a tail lamp 47 and a rear fender 48 are provided at the rear part of the side cover 23. Inside the side cover 23, a fuel tank (not shown) is disposed below the seat 5, and an engine 6 is provided further below the fuel tank. As shown in FIG. 4, an injector (fuel injection device, component) 7 that controls fuel supply is attached to the left front portion of the engine 6. Fuel is sent from the fuel tank to the injector 7 through the fuel hose 71.

  A shroud (air guide member) 101 that covers a part of the engine 6 is attached to the right side of the engine 6. An opening O1 is provided on the right side surface of the shroud 101, and a fan (air blowing member) 102 is disposed inside the shroud 101 corresponding to the opening O1 (see FIG. 3). The fan 102 is connected to a crankshaft (not shown) so as to be rotated by the power of the engine 6 and takes air into a space covered by the shroud 101. The engine 6 is forcibly cooled by the shroud 101 and the fan 102 even during idling.

  The engine 6, transmission (not shown), and the like are integrated with a unit swing 8 that can swing up and down. A rear cushion unit 81 is attached between the unit swing 8 and the frame 11. The rear wheel 4 is rotatably supported at the rear part of the unit swing 8. A mission cover 41 is disposed on the left side of the rear wheel 4. The power of the engine 6 is transmitted to the rear wheel 4 via a pulley and a belt (both not shown) stored in the mission cover 41. In addition, a stand 42 that supports the vehicle body at the time of parking is provided in front of the mission cover 41 (lower left of the step board 22) (see FIG. 1).

  An air cleaner box 43 is disposed above the mission cover 41. The air taken into the air cleaner box 43 is sent to the engine 6 through the intake hose 44, the throttle body 45, and the intake manifold 46. The combustion chamber of the engine 6 is supplied with a mixture of air from the intake manifold 46 and fuel from the injector 7. The gas after combustion is discharged as exhaust gas from a muffler 61 provided on the right rear side of the engine 6.

  Next, the engine 6 and its cooling structure according to the present embodiment will be described. FIG. 5 is a cross-sectional view of the engine 6 cut along a plane perpendicular to the vehicle width direction. As shown in FIGS. 4 and 5, in the engine 6, a substantially cylindrical cylinder 112 is disposed in front of the crankcase 111, and a cylinder head 113 and a cylinder head cover 114 are attached to the front of the cylinder 112. The cylinder 112 is provided with a plurality of heat radiation fins 112b.

  A crankshaft (not shown) is accommodated in the crank chamber 111a in the crankcase 111 so that the rotation shaft is parallel to the vehicle width direction. A cylindrical space 112a in the cylinder 112 accommodates a piston (not shown) that can reciprocate in the cylinder axis direction (front-rear direction). The crankshaft and the piston are connected via a connecting rod (not shown) so that the reciprocating motion of the piston is converted into the rotational motion of the crankshaft.

  The cylinder head 113 is formed with an intake port 113a for sending a mixture of air and fuel into the combustion chamber, and an exhaust port 113b for discharging the gas after combustion outside the combustion chamber. An intake manifold 46 and an injector 7 are connected to the intake port 113a, and air and fuel are supplied. The cylinder head 113 is provided with an intake valve 113c for opening and closing the intake port 113a and an exhaust valve 113d for opening and closing the exhaust port 113b. An ignition plug (not shown) is provided adjacent to the intake port 113a and the exhaust port 113b, and the air-fuel mixture in the combustion chamber can be ignited by electric discharge.

  The intake / exhaust mechanism of the engine 6 is an OHC (Overhead Camshaft) that opens and closes the intake valve 113c and the exhaust valve 113d by a camshaft (not shown). The camshaft includes a cam (not shown) having a shape corresponding to the opening / closing timing of the intake valve 113c or the exhaust valve 113d. One end of the camshaft is connected to the crankshaft via a power transmission mechanism (not shown) such as a sprocket or a cam chain. Thereby, the rotational force of the crankshaft is transmitted to the camshaft, and the intake valve 113c and the exhaust valve 113d are opened and closed so as to correspond to the rotation of the crankshaft.

  In the engine 6 as described above, when the piston moves toward the bottom dead center, the intake valve 113c is opened, and air and fuel are sent into the combustion chamber through the intake manifold 46 and the injector 7 (intake stroke). Thereafter, the intake valve 113c is closed, and the air-fuel mixture is compressed by moving the piston toward the top dead center (compression stroke). When the piston reaches top dead center, the compressed air-fuel mixture ignited by the spark plug burns (combustion stroke). When the pressure in the combustion chamber increases due to the combustion of the air-fuel mixture, the piston moves toward the bottom dead center. Thereafter, when the piston reaches the bottom dead center and begins to move toward the top dead center again due to inertia, the exhaust valve 113d is opened, and the burned gas is discharged from the exhaust port 113b (exhaust stroke). The valve operating device including the intake valve 113c and the exhaust valve 113d provided in the cylinder head 113 enables such an operation.

  As described above, the engine 6 repeats the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke, thereby converting the reciprocating motion of the piston into the rotational motion of the crankshaft. For this reason, the cylinder 112 and the cylinder head 113 are heated with the operation of the engine 6. In the engine 6 of the present embodiment, the cylinder 112 and the cylinder head 113 are cooled and kept at an appropriate temperature by the cooling structure including the shroud 101 and the fan 102.

  FIG. 6 is an explanatory diagram for explaining the cooling structure according to the present embodiment. FIG. 7 is a perspective view showing the shape of the shroud 101. As shown in FIGS. 6 and 7, the shroud 101 includes a right half 101 </ b> R that covers the right side of the engine 6 and a left half 101 </ b> L that covers the left front side of the engine 6.

  The right half 101R extends to the left from the right wall WR that covers the right front side of the engine 6, the upper right wall WRU that extends leftward (inward in the vehicle width direction) from the front upper end of the right wall WR, and the front lower end of the right wall WR. A right lower wall WRD and a right front wall WRF extending leftward from the front end of the right wall WR are provided. The right wall WR is formed so as to cover the right side surface of the crankcase 111, the cylinder 112, and the cylinder head 113. The upper right wall WRU is formed to cover the upper right side of the cylinder 112 and the cylinder head 113, and the lower right wall WRD is formed to cover the lower right side of the cylinder 112 and the cylinder head 113.

  The left half 101L includes a left wall WL covering the left front side of the engine 6, a left upper wall WLU extending rightward (inward in the vehicle width direction) from the upper end of the left wall WL, and a lower left wall extending rightward from the lower end of the left wall WL. WLD. The left wall WL is formed so as to cover the left side surfaces of the cylinder 112 and the cylinder head 113. The upper left wall WLU is formed to cover the upper left side of the cylinder 112 and the cylinder head 113, and the lower left wall WLD is formed to cover the lower left side of the cylinder 112 and the cylinder head 113.

  The right wall WR, the upper right wall WRU, the lower right wall WRD, the left wall WL, the upper left wall WLU, and the lower left wall WLD of the left half 101L are all a crankcase 111, a cylinder 112, and a cylinder head 113. It is arranged in the position away from. That is, in a state where the shroud 101 is attached to the engine 6, a space through which air flows is formed between the crankcase 111, the cylinder 112, the cylinder head 113, and the shroud 101.

  In the right half 101R, a cylindrical portion C protruding rightward (outward in the vehicle width direction) is provided at the rear of the right wall WR, and an opening O1 serving as an intake port is provided at the right end of the cylindrical portion C. Is formed. The cylindrical portion C and the opening O1 are provided at positions corresponding to the fan 102. That is, with the shroud 101 attached to the engine 6, the fan 102 is disposed in the space on the left side of the cylindrical portion C (in the vehicle width direction).

  When the fan 102 rotates in this cooling structure, air is taken into the shroud 101 through the opening O1. The air taken into the shroud 101 flows through a space formed between the shroud 101 and the engine 6. The rotation of the fan 102 creates an air flow in the shroud 101 from the right rear space of the engine 6 to the left front space via the right front space, and the cylinder 112, the cylinder head 113, and The injector 7 is cooled. As described above, a cooling flow path for cooling the cylinder 112, the cylinder head 113, and the injector 7 is formed in the shroud 101.

  By the way, when the air whose temperature has passed through the cylinder 112 and the cylinder head 113 is guided to the injector 7 by this cooling flow path, the cooling efficiency of the injector 7 is greatly reduced. Therefore, in the cooling structure according to the present embodiment, a shielding portion that divides the cooling flow path is arranged in the shroud 101, and the air flow path for cooling the cylinder 112 and the cylinder head 113 and the injector 7 are cooled. To separate the air flow path.

  FIG. 8 is a perspective view showing the configuration of the shielding part. As shown in FIGS. 7 and 8, the shielding portion 103 has a curved shape along the inner wall surface of the right half portion 101 </ b> R of the shroud 101. Specifically, the shielding portion 103 includes an upstream portion 103a disposed along the right wall WR and the upper right wall WRU of the shroud 101, a midstream portion 103b disposed along the right front wall WRF and the upper right wall WRU, And a downstream portion 103 c that forms a flow of air toward the injector 7. By attaching the shielding portion 103 to the inner wall surface of the shroud 101, a branch channel that branches the cooling channel is formed.

  Inside the shroud 101 to which the shielding part 103 is attached, an opening part O2 for taking air from the fan 102 into the branch flow path is formed by the upstream part 103a, the right wall WR, and the upper right wall WRU. Further, the air flowing in from the opening O2 is guided to the left front by the midstream portion 103b, the right front wall WRF, and the upper right wall WRU. Thus, since the branch flow path is formed at a position away from the cylinder 112 and the cylinder head 113 along the inner wall surface of the shroud 101, the propagation of heat from the cylinder 112 and the cylinder head 113 to the branch flow path is prevented. It is suppressed.

  In this cooling structure, the upstream portion 103a is disposed along the flow of air from the fan 102, and the branch flow path is bent only in the boundary region between the upstream portion 103a and the midstream portion 103b. For this reason, air can flow smoothly in the branch flow path, and high cooling efficiency can be obtained. In the downstream portion 103c, a rectifying portion 103d that regulates the air flow is disposed in a region in contact with the right front wall WRF. The flow of air toward the injector 7 is adjusted by the rectifying unit 103d, and the cooling efficiency of the injector 7 is enhanced.

  Further, the area of the opening O2 is sufficiently large, and the flow rate of air necessary for cooling the injector 7 is secured. By changing the area of the opening O2, the flow rate of air for cooling the injector 7 can be adjusted. The shield 103 may be formed of a material different from that of the shroud 101. For example, the propagation of heat from the cylinder 112 and the cylinder head 113 to the branch flow path can be further suppressed by forming the shielding portion 103 using a material having high heat insulating properties. The same effect can be obtained also when a heat insulating member is attached to the shielding part 103.

  FIG. 9 is a schematic diagram showing an air flow in the cooling structure according to the present embodiment. As shown in FIG. 9, the air taken into the shroud 101 from the opening O1 is sent forward by a fan 102 (not shown in FIG. 9). A part of the air is supplied to the cylinder 112 and the cylinder head 113 through the cooling flow path P1. Another part of the air flows into the opening O2 and is blown to the injector 7 through the branch flow path P2. The cylinder 112 and the cylinder head 113 are cooled by the air supplied through the cooling flow path P1, and the injector 7 is cooled by the air blown through the branch flow path P2.

  Thus, the cooling efficiency of the injector 7 can be improved by blowing air to the injector 7 through the branch flow path P2 formed exclusively for cooling the injector 7. Since this branch channel P2 is formed so as to sandwich the cooling channel P1 between the cylinder 112 and the cylinder head 113, the cooling channel P1 is not blocked by the branch channel P2. Therefore, the cooling efficiency of the cylinder 112 and the cylinder head 113 is also maintained high.

  As described above, according to the engine cooling structure according to the present invention, the shroud (wind guide member) 101 forms the branch passage P2 that guides air to the injector (fuel injection device, component) 7. Therefore, the injector 7 can be cooled with air different from the air that cools the cylinder 112 and the cylinder head 113. Further, since the branch flow path P2 is formed at a position away from the cylinder 112 and the cylinder head 113, the propagation of heat from the cylinder 112 and the cylinder head 113 to the branch flow path P2 is suppressed, and the cooling efficiency of the injector 7 is reduced. Can be increased. Therefore, an engine cooling structure capable of appropriately cooling components such as the injector 7 affected by the heat of the cylinder 112 and the cylinder head 113 is realized.

  Moreover, since the shielding part 103 branched the cooling flow path P1 in the position before the air from the fan (blower member) 102 reached the cylinder 112 and the cylinder head 113, it branches by the heat of the cylinder 112 and the cylinder 113. The temperature rise of the air flowing through the flow path P2 can be prevented. Therefore, the cooling efficiency of components such as the injector 7 can be increased.

  Further, since the branch flow path P2 is formed along the inner wall surface of the shroud 101 so as to sandwich the cooling flow path P1 between the cylinder 112 and the cylinder head 113, the branch flow path P2 extends from the cylinder 112 and the cylinder head 113. The propagation of heat to P2 can be further suppressed. Further, since the cooling flow path P1 is not blocked by the branch flow path P2, the cooling efficiency of the cylinder 112 and the cylinder head 113 can be maintained high.

  Moreover, since the shielding part 103 is comprised with a member different from the shroud 101, since the freedom degree of a shape increases compared with the case where the shroud 101 and the shielding part 103 are shape | molded integrally, the cooling flow path P1 and It is possible to reliably separate the branch flow path P2 and suppress the propagation of heat from the cylinder 112 and the cylinder head 113 to the branch flow path P2. Moreover, since the material of the shroud 101 and the material of the shielding part 103 can be changed, the heat insulation effect of the shielding part 103 is enhanced, and the propagation of heat from the cylinder 112 and the cylinder head 113 to the branch flow path P2 is further suppressed. Can do.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above embodiment, the configuration in which the injector is cooled by the air flowing through the branch flow path is exemplified, but the engine cooling structure according to the present invention is not limited thereto. In an engine using a carburetor as a fuel injection device, the carburetor may be cooled with air flowing through a branch flow path. The cooling target may be at least a component different from the cylinder and the cylinder head. In the present embodiment, the branch channel is formed inside the shroud, but the branch channel may be formed outside the shroud.

  Moreover, the shielding part may be configured to be detachable so that the area of the opening of the branch flow path can be changed by replacing the shielding part. In this case, the flow rate of the air that cools the injector can be arbitrarily adjusted. Moreover, in this Embodiment, although a shroud and a shielding part are made into another member, a shroud and a shielding part are good also as one member comprised integrally. When the shroud and the shielding portion are integrated, the manufacturing cost of the cooling structure can be suppressed.

  The engine cooling structure according to the present invention is useful, for example, as an engine cooling structure in a motorcycle.

1 Motorcycle 6 Engine 7 Injector (fuel injection device, parts)
43 Air cleaner box 44 Intake hose 45 Throttle body 46 Intake manifold 61 Muffler 71 Fuel hose 101 Shroud (air guide member)
101R Right half 101L Left half 102 Fan (Blowing member)
103 Shielding part 103a Upstream part 103b Midstream part 103c Downstream part 103d Rectifying part 111 Crankcase 112 Cylinder 113 Cylinder head 114 Cylinder head cover C Cylindrical part O1, O2 Opening P1 Cooling flow path P2 Branch flow path WL Left wall WLD Left lower wall WLU Upper left Wall WR Right wall WRD Lower right wall WRU Upper right wall

Claims (5)

An air guide member that covers a part of a cylinder and a cylinder head of an engine and forms a cooling flow path that guides cooling air to the cylinder and the cylinder head; and a blower member that sends the air to the cooling flow path A fuel injection device disposed in an intake port of the engine, and an engine cooling structure comprising:
The engine is arranged with a cylinder axis line in the front-rear direction so that the intake port is directed upward with respect to the exhaust port,
It said air guide member, have a blocking portion that form the branch flow path of the air is branched to the cooling passage leading to the fuel injection device,
The branch flow path is formed along the inner wall surface of the air guide member so as to sandwich the cooling flow path between the cylinder and the cylinder head at a position away from the cylinder and the cylinder head. ,
The engine cooling structure characterized in that the air blown to the fuel injection device through the branch passage is discharged from above the vehicle .   The engine cooling structure according to claim 1, wherein the shielding portion branches the cooling flow path at a position before the air from the air blowing member reaches the cylinder and the cylinder head. 3. The engine cooling structure according to claim 1 , wherein the shielding portion is formed of a member different from the air guide member. An exhaust pipe for guiding exhaust gas discharged from the exhaust port of the engine to a muffler;
The branch flow path sandwiches the cooling flow path between the cylinder and the cylinder head in the vehicle width direction and between the exhaust pipe at a position away from the exhaust pipe in the vehicle vertical direction. The engine cooling structure according to any one of claims 1 to 3, wherein the cooling channel is formed so as to sandwich the cooling channel vertically. The said shielding part has a rectification | straightening part which arranges the flow of the said air in the upstream of the said fuel injection apparatus in the downstream part of the said branch flow path, The Claim 1 characterized by the above-mentioned. Engine cooling structure.

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