Saddle-ridden type vehicle

There is provided a saddle-ridden type vehicle. An oil cooler cools engine oil to be supplied to an engine. A supercharger compresses combustion air to be supplied to the engine. A water pump pumps cooling water to the engine and the supercharger. A cooling piping flows the cooling water delivered from the water pump. A first inlet piping supplies the cooling water to the oil cooler. A second inlet piping is disposed in parallel with the first inlet piping and supplies the cooling water to the supercharger. A first outlet piping extends upward from the oil cooler and returns the cooling water to the water pump. A second outlet piping extends upward from the supercharger and returns the cooling water to the water pump. The first outlet piping and the second outlet piping converge above the oil cooler and the supercharger.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure of Japanese Patent Application No. 2015-210465 filed on Oct. 27, 2015, including specification, drawings and claims is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The disclosure relates to a saddle-ridden type vehicle including an engine having a supercharger.

BACKGROUND

A saddle-ridden type vehicle such as a motorcycle may include an engine having a supercharger so as to improve a fuel consumption and an output. The engine having the supercharger has a cooling device for cooling an oil cooler and the supercharger.

For example, the cooling device of the engine having the supercharger disclosed in Patent Document 1 has a cooling water passage (for discharge) configured to supply cooling water, which is discharged from the engine, to a radiator and a cooling water passage (for supply) configured to supply the cooling water cooled at the radiator to the engine. The oil cooler and the supercharger are connected to the cooling water passage (for discharge) via two cooling water supply passages disposed in parallel. Two cooling water discharge passages extending from the oil cooler and the supercharger converge on the way, which is connected to the cooling water passage (for supply). A water pump for pumping the cooling water to the engine is interposed on the cooling water passage (for supply).

Most of the cooling water discharged from the engine is cooled while passing through the radiator, and is again supplied to the engine through the cooling water passage (for supply). A part of the cooling water discharged from the engine passes through the two cooling water supply passages and cools the oil cooler and the supercharger. The cooling water having cooled the oil cooler and the supercharger passes through the two cooling water discharge passages and converges on the cooling water passing through the cooling water passage (for supply).

In the above technology, the oil cooler and the supercharger are cooled using the cooling water having cooled the engine. However, in some cases, it is not possible to sufficiently cool the oil cooler and the supercharger by the cooling water of which temperature has increased after cooling the engine. Also, the high-temperature cooling water having cooled the supercharger and the like is mixed with the low-temperature cooling water cooled at the radiator in the cooling water passage (for supply). In this case, the temperature of the cooling water that is to be supplied to the engine becomes unstable.

SUMMARY

It is therefore an object of the disclosure to provide a saddle-ridden type vehicle capable of appropriately cooling an oil cooler and a supercharger and stabilizing a temperature of cooling water to be supplied to an engine and the like.

According to an aspect of the embodiments of the present invention, there is provided a saddle-ridden type vehicle comprising: an engine; an oil cooler configured to cool engine oil to be supplied to the engine; a supercharger configured to compress combustion air to be supplied to the engine; a water pump configured to pump cooling water to the engine and the supercharger; and a cooling piping configured to flow the cooling water delivered from the water pump, wherein the cooling piping comprises: a first inlet piping configured to supply the cooling water delivered from the water pump to the oil cooler; a second inlet piping disposed in parallel with the first inlet piping and configured to supply the cooling water delivered from the water pump to the supercharger; a first outlet piping extending upward from the oil cooler and configured to return the cooling water having cooled the oil cooler to the water pump; and a second outlet piping extending upward from the supercharger and configured to return the cooling water having cooled the supercharger to the water pump, and wherein the first outlet piping and the second outlet piping converge above the oil cooler and the supercharger.

According to the above configuration, the oil cooler (engine oil) is cooled by the cooling water supplied through the first inlet piping. The supercharger is cooled by the cooling water supplied through the second inlet piping. Since the first inlet piping and the second inlet piping are disposed in parallel, the cooling water necessary for cooling of the oil cooler and the cooling water necessary for cooling of the supercharger are separately supplied. Also, the oil cooler and the supercharger are supplied with the cooling water from the water pump, which has not been used for other cooling. Thereby, it is possible to appropriately cool the oil cooler and the supercharger.

In the saddle-ridden type vehicle, the cooling piping may further comprise a convergence piping configured to converge the first outlet piping and the second outlet piping and connected to a circulation path of the cooling water positioned above the oil cooler and the supercharger.

According to the above configuration, the first outlet piping and the second outlet piping are made to converge at the convergence piping, so that it is possible to unify circulation destinations with the circulation path.

The saddle-ridden type vehicle may further comprise: a radiator configured to cool the cooling water; a cooling water flow control unit disposed above the oil cooler and the supercharger and configured to regulate an amount of the cooling water to flow in the radiator in accordance with a temperature of the cooling water; and a core piping configured to communicate the cooling water flow control unit and the water pump each other, and the convergence piping may be configured to communicate with the core piping via the cooling water flow control unit serving as the circulation path.

When the water pump stops as the engine stops, for example, the cooling water flowing through the cooling piping also stops. Thereafter, the cooling water is heated at the supercharger, thereby generating water vapor. According to the above configuration, since the cooling water flow control unit is disposed above the supercharger and the like, the generated water vapor smoothly moves downstream through the respective outlet pipings and the convergence piping. Then, the cooling water upstream of the supercharger is supplied to the supercharger by a pressure equilibrium action between the supercharger and the cooling piping. Thereby, even after the engine stops, it is possible to continuously cool the supercharger. Also, the cooling water used for cooling of the engine, the oil cooler and the supercharger is collected to the cooling water flow control unit and is then cooled by the radiator. Thereby, it is possible to stabilize a temperature of the cooling water, which is to pass through the radiator and to be supplied to the engine.

In the saddle-ridden type vehicle, an inner diameter of the convergence piping may be made greater than an inner diameter of the first outlet piping and may be made greater than an inner diameter of the second outlet piping.

According to the above configuration, since the inner diameter of the convergence piping is made greater than the inner diameters of the respective outlet pipings, it is possible to enable the cooling water to smoothly flow from the respective outlet pipings to the convergence piping. Thereby, it is possible to improve cooling performances of the oil cooler and the supercharger.

In the saddle-ridden type vehicle, the oil cooler may be disposed at a front-lower side of the engine, the supercharger may be dispose above the oil cooler, and the cooling piping may be disposed at an inner side relative to a length of the engine in a vehicle width direction, as seen from the front, and may be disposed at a rear side of a front end portion of the supercharger, as seen from a side.

According to the above configuration, the cooling piping is intensively disposed near a front side of the engine, so that it is possible to miniaturize the engine having the supercharger.

In the saddle-ridden type vehicle, the cooling piping may further comprise a branched piping configured to branch a tip portion thereof extending from the water pump and connected to the first inlet piping and the second inlet piping, and an inner diameter of the branched piping may be made greater than an inner diameter of the first inlet piping and may be made greater than an inner diameter of the second inlet piping.

According to the above configuration, since the inner diameter of the branched piping is made greater than the inner diameters of the respective inlet pipings, it is possible to sufficiently secure flow rates of the cooling water before the cooling water is split into the respective inlet pipings. Thereby, it is possible to sufficiently supply the cooling water to the oil cooler and the supercharger.

According to the disclosure, it is possible to appropriately cool the oil cooler and the supercharger. Also, it is possible to stabilize the temperature of the cooling water that is to be supplied to the engine and the like.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a preferred illustrative embodiment of the disclosure will be described with reference to the accompanying drawings. Meanwhile, in below descriptions, front, rear, right, left, upper and lower directions are described on the basis of a driver who sits on a seat of a motorcycle.

An overall configuration of a motorcycle1in accordance with the illustrative embodiment is described with reference toFIG. 1.FIG. 1is a left side view depicting the motorcycle1.

A vehicle body frame211of the motorcycle1is formed by joining a plurality of steel pipes, for example. Specifically, the vehicle body frame211has a head pipe212disposed at a front-upper side of the motorcycle1, a pair of main frames213each of which is disposed at right and left sides of the motorcycle1, respectively and has a front end portion connected to an upper part of the head pipe212and a rear end extending rearward with being inclined downward, a pair of down tubes214each of which is disposed at the right and left sides of the motorcycle1and has a front end portion connected to a lower part of the head pipe212and a rear end extending rearward with being inclined downward beyond the main frame213, a pair of side frames215each of which is disposed at the right and left sides of the motorcycle1and has a front end portion connected to an intermediate part of the down tube214and a rear end extending rearward, and a pair of pivot frames216joined to the rear ends of the main frames213. Also, a reinforcement frame217is provided among the main frame213, the down tube214and the side frame215.

A steering shaft (not shown) is inserted into the head pipe212, and upper and lower end portions of the steering shaft are respectively provided with steering brackets225. The upper steering bracket225is provided with a handlebar226. A pair of right and left front forks227is supported at upper parts thereof to the upper and lower steering brackets225, and a front wheel228is supported to lower ends of the front forks227.

A front end of a swing arm232is supported between the pair of right and left pivot frames216via a pivot shaft231, and a rear wheel233is supported to a rear end of the swing arm232. An axle of the rear wheel233is provided with a driven sprocket234, and a chain235configured to transmit power of an engine12(which will be described later) is wound on the driven sprocket234.

An engine unit11is provided between the front wheel228and the rear wheel233. The engine unit11is mainly disposed between the left main frame213and left down tube214and the right main frame213and right down tube214and is supported to the corresponding frames.

A fuel tank241is provided above the engine unit11, and a seat242is provided at the rear of the fuel tank241. A side stand243is provided at the left side of the motorcycle1, i.e., at a lower-rear part of the engine unit11. An upper cowl244is provided at a front-upper side of the motorcycle1. The motorcycle1is provided with an under cowl245configured to mainly cover a front-lower side of the engine unit11.

Subsequently, the engine unit11is described with reference toFIGS. 2 to 9.FIG. 2is a left side view depicting the engine unit11.FIG. 3is a right side view depicting the engine unit11.FIG. 4is a front view depicting the engine unit11(excluding a radiator).FIG. 5is a plan view depicting the engine unit11.FIG. 6is a front view depicting the engine unit11(including a radiator).FIG. 7is a plan view depicting an engine12and a cooling system.FIG. 8is a sectional view pictorially depicting the cooling system of the engine unit11.FIG. 9is a front view depicting the engine12and a cooling piping61.

The engine unit11has an engine12, parts of a driving system such as a primary deceleration mechanism configured to transmit power of the engine12to the rear wheel233, a clutch, a transmission and the like, a lubrication system configured to lubricate a moveable part of the engine12, an intake system (including a supercharger113) configured to supply a fuel-air mixture of air and fuel to the engine12, parts of an exhaust system configured to discharge an exhaust gas, which is to be generated as the fuel-air mixture is combusted, from the engine12, a cooling system configured to cool the engine12and the like, an AC generator configured to generate power by using rotation of a crankshaft, and the like.

In the illustrative embodiment, the engine12is a water-cooling type parallel two-cylinder four-cycle gasoline engine, for example. As shown inFIGS. 2 and 3, the engine12has a crank case13configured to accommodate therein a crankshaft (not shown), a cylinder14provided on the crank case13, a cylinder head15provided on the cylinder14and a cylinder head cover16provided on the cylinder head15.

An oil pan17is provided below the crank case13. A cylinder axis of the engine12is inclined so that an upper side is located at a forward position relative to a lower side. The engine12is provided with a balance shaft (not shown) configured to reduce vibrations, which are to be generated by movement of a piston. The balance shaft is disposed in front of the crankshaft. Specifically, a balancer chamber18is integrally formed at a front part of the crank case13of the engine12(refer toFIG. 2). The balancer chamber18is formed by expanding forward a part of the crank case13. The balance shaft is provided in the balancer chamber18. A left part of the crank case13is provided with a magneto chamber19(refer toFIG. 2), and the AC generator (not shown) is accommodated in the magneto chamber19.

A part of the driving system of the engine unit11is disposed at the rear of the engine12. That is, a transmission case21is integrally formed at the rear of the crank case13and the cylinder14, and the primary deceleration mechanism and the transmission are accommodated in the transmission case21. A clutch cover22configured to cover the clutch is attached to a right part of the transmission case21(refer toFIG. 3). A sprocket cover23configured to cover a drive sprocket is provided at a left part of the transmission case21(refer toFIG. 2). The drive sprocket is wound with a chain235configured to transmit the power of the engine12to the rear wheel233(refer toFIG. 1).

As shown inFIGS. 2 to 4, the lubrication system of the engine unit11has an oil pump (not shown), an oil filter25and a water-cooling type oil cooler26. The oil pump is configured to pump engine oil stored in the oil pan17of the engine12and to supply the same to the respective parts of the engine12. The oil filter25is configured to filter the engine oil. The oil cooler26is configured to cool the engine oil to be supplied to the engine12. The oil filter25and the oil cooler26are disposed side by side at the front of the lower end portion of the engine12and in the vicinity of a center in a right-left direction (vehicle width direction) (refer toFIG. 4).

As shown inFIGS. 2 to 5, the intake system of the engine unit11has an air cleaner111, a supercharger113, an intercooler117, an air discharging duct118, a surge tank119, an electronic control throttle device120and an injector123.

As shown inFIGS. 4 and 5, the air cleaner111is disposed at an upper-left side of the engine12. The air cleaner111is a device configured to filter air introduced from an outside, and has therein an air filter (not shown). InFIGS. 2 and 5, an intake port112of the air cleaner111is pictorially shown by a dashed-two dotted line. A position of the intake port112can be appropriately set. Also, the intake port112is provided with an air duct (not shown) configured to guide the outside air into the air cleaner111.

As shown inFIGS. 2 to 4, the supercharger113is disposed at the front of the cylinder14and the cylinder head15and in the vicinity of the upper of the oil cooler26. The supercharger113is configured to compress combustion air to be supplied to the engine12.

As shown inFIG. 4, the supercharger113has a turbine unit114, a compressor unit115and a bearing unit116.

The turbine unit114is disposed at a substantial center of the engine12in the right-left direction. The turbine unit114includes a turbine wheel (not shown) rotatably supported in a turbine housing. The turbine wheel is configured to rotate by the exhaust gas from the engine12. The compressor unit115is disposed at the left of the turbine unit114. The compressor unit115includes a compressor impeller (not shown) rotatably supported in a compressor housing. The compressor impeller is configured to rotate together with the turbine wheel and to compress the air supplied via the air cleaner111. The bearing unit116is disposed between the turbine unit114and the compressor unit115. The bearing unit116includes a bearing (not shown) configured to pivotally support the turbine wheel and the compressor impeller at an intermediate part. The bearing unit116is supplied with the engine oil by the driving of the oil pump. In the meantime, the compressor unit115may be disposed at the right of the turbine unit114.

As shown inFIGS. 3 to 5, the intercooler117is disposed at an upper-right side of the engine12. The intercooler117is a device configured to cool the air of which temperature has increased resulting from the compression by the compressor unit115of the supercharger113. The air discharging duct118configured to discharge the air (discharge air) having passed through the intercooler117to the outside is provided in the vicinity of the intercooler117. As shown inFIGS. 2 and 5, the surge tank119is disposed at an upper-rear side of the engine12. The surge tank119is a device configured to rectify the flow of the air cooled by the intercooler117.

The electronic control throttle device120is a device configured to regulate an amount of the air, which is to pass through the intercooler117and is to be supplied to the intake port of the engine12. As shown inFIG. 2, the electronic control throttle device120has a throttle body121, a throttle valve (not shown) provided in the throttle body121and configured to open and close an intake passage formed in the throttle body121, and a driving motor122configured to drive a throttle valve. The throttle body121is disposed between the surge tank119and the intake port of the engine12at the rear-upper side of the engine12.

The injector123is a device configured to inject the fuel to the intake port of the engine12. To the injector123, a delivery pipe124configured to supply the fuel from the fuel tank241to the injector123is connected.

The respective parts configuring the intake system are connected as follows. As shown inFIGS. 4 and 5, an air intake pipe125is connected between the air cleaner111and the compressor unit115of the supercharger113. The air intake pipe125is disposed at a front-left side of the engine12. Also, an air outlet pipe126is connected between the compressor unit115and the intercooler117. The air outlet pipe126is disposed at the front-left side of the engine12and at the right of the air intake pipe125. As shown inFIG. 5, a connecting pipe127is connected between the intercooler117and the surge tank119. The connecting pipe127is disposed at the right-rear side of the upper of the engine12.

As shown inFIGS. 4 and 5, the air introduced from the outside normally sequentially passes through the air cleaner111, the air intake pipe125, the compressor unit115of the supercharger113, the air outlet pipe126, the intercooler117, the connecting pipe127, the surge tank119and the throttle body121of the electronic control throttle device120, and is then supplied to the intake port of the engine12. An air bypass passage128(refer toFIGS. 2 and 4) configured to bypass the compressor unit115and to connect the air intake pipe125and the air outlet pipe126therebetween is provided in the vicinity of the supercharger113, and an air bypass valve129configured to switch communication and cutoff of the air bypass passage128is provided on the way of the air bypass passage128(refer toFIGS. 2 and 5).

As shown inFIG. 4, the exhaust system of the engine unit11has exhaust pipes131configured to connect exhaust ports (not shown) of the engine12and the turbine unit114of the supercharger113therebetween, a muffler joint pipe132configured to connect the turbine unit114of the supercharger113and a muffler-side, a muffler (not shown), and the like.

The exhaust pipes131configure a part of the engine unit11. The exhaust pipes131are disposed at the front of the engine12. In the illustrative embodiment, the exhaust pipes131are integrally formed with the turbine housing of the turbine unit114. Specifically, one ends of the two exhaust pipe131are respectively connected to the two exhaust ports of the parallel two-cylinder engine12. The other ends of the exhaust pipes131are coupled to each other to form one, which is integrated with the turbine housing of the turbine unit114. In the meantime, the exhaust pipe131may be separately provided from the turbine housing and may be coupled to the turbine housing. Meanwhile, the muffler joint pipe132has one end connected to the turbine housing of the turbine unit114and the other end passing the lower-right side of the engine12and extending rearward toward the muffler. Also, the muffler is disposed at a rear-lower side of the engine12.

The exhaust gas discharged from the respective exhaust ports is supplied into the turbine unit114via the exhaust pipes131. By the exhaust gas, the turbine of the turbine unit114is rotated. Subsequently, the exhaust gas discharged from the turbine unit114is supplied to the muffler via the muffler joint pipe132and is discharged from the muffler to the outside.

The turbine unit114of the supercharger113is provided with a waste gate valve133. That is, the turbine unit114is provided therein with a gate configured to circulate a part of the exhaust gas supplied via the exhaust pipes131toward the muffler joint pipe132without supplying the same to the turbine. The waste gate valve133is configured to regulate an inflow amount of the exhaust gas to the turbine by opening and closing the gate.

As shown inFIG. 3, the cooling system of the engine unit11has a water jacket (not shown), a water pump30, a radiator33, a cooling water flow control unit41, a core piping51, and a cooling piping61.

The water jacket is provided in the cylinder14and the cylinder head15. The cylinder14and the cylinder head15are cooled by the cooling water flowing through the water jacket.

As shown inFIGS. 3 and 4, the water pump30is attached to the right side of the crank case13. The water pump30is disposed at a position corresponding to the balance shaft positioned in front of the crankshaft. The water pump30is provided with a pump inlet31. The water pump30is formed with a supply part30A for supplying the cooling water to the water jacket. A front side of the water pump30is provided with a cooling water discharge port30B. The water pump30is configured to operate by using the rotation of the crankshaft and to supply the cooling water to the engine12(water jacket) and the supercharger113.

As shown inFIGS. 2, 3 and 6, the radiator33is disposed at the front side of the engine12. The radiator33is configured to receive traveling wind or to drive a radiator fan40, thereby radiating the heat of the cooling water to the atmosphere to cool the cooling water. The radiator33has an upper radiator34and a lower radiator35.

The upper radiator34and the lower radiator35are disposed with being spaced vertically, and are connected to each other via a pair of right and left connecting hoses36. As shown inFIG. 7, the radiator fan40is attached to a rear surface of the upper radiator34. A radiator inlet37is provided at a left-upper side of the rear surface of the upper radiator34(refer toFIG. 2). A radiator outlet38is provided at a right-upper side of the rear surface of the upper radiator34(refer toFIG. 3).

As shown inFIG. 3, a cooling water supply port39to which a water injection hose56extending upward is connected is formed at a right-lower side of the rear surface of the upper radiator34. An upper end portion of the water injection hose56is provided with a cooling water injection part58having a cooling water injection port57. Also, the radiator33is connected with a reservoir tank59via an overflow pipe line (not shown).

As shown inFIGS. 6 and 7, the cooling water flow control unit41functioning as a circulation path is disposed above the oil cooler26and the supercharger113. Specifically, the cooling water flow control unit41is disposed at a right-front side above the cylinder head cover16, and is attached to a part of the engine12or the vehicle body frame211. The cooling water flow control unit41is provided to adjust an amount of the cooling water to flow through the radiator33in accordance with a temperature of the cooling water. Thereby, it is possible to keep the cooling water at a predetermined appropriate temperature.

As shown inFIG. 8, the cooling water flow control unit41has a thermostat housing42and a thermostat43. The thermostat housing42has a left housing42L and a right housing42R. The thermostat43is provided in the right housing42R.

A first cooling water inlet44is formed at a rear side of the left housing42L. A second cooling water inlet45is formed at a left side of the left housing42L. A cooling water delivery port46is formed at a front side of the left housing42L. The first cooling water inlet44, the second cooling water inlet45and the cooling water delivery port46are configured to respectively communicate with an inside of the left housing42L. A water temperature sensor S configured to detect the temperature of the cooling water flowing in the left housing42L is attached to a rear-left side of the left housing42L.

A cooling water return port47is formed at a front side of the right housing42R. A cooling water outlet48is formed at a rear side of the right housing42R. The cooling water return port47and the cooling water outlet48are configured to respectively communicate with an inside of the right housing42R.

A cooling water bypass passage49is formed between the left housing42L and the right housing42R. The cooling water bypass passage49is configured to communicate the inside of the left housing42L and the inside of the right housing42R each other.

The thermostat43is provided to open and close the cooling water bypass passage49in accordance with the temperature of the cooling water. The thermostat43has a valve seat43A, a main valve body43B, a thermoelement43C, and a sub-valve body43D.

The valve seat43A is fixed in the right housing42R. The main valve body43B and the sub-valve body43D are fixed to the thermoelement43C. The main valve body43B is configured to be separated from or to be seated on the valve seat43A. The sub-valve body43D is configured to be separated from or to be seated on an opening edge portion (hereinafter, referred to as “sub-valve seat43E”) of the cooling water bypass passage49. The thermoelement43C is configured to move the main valve body43B and the sub-valve body43D in the right-left direction in accordance with the temperature of the cooling water. The main valve body43B is configured to open and close a flow passage between the cooling water return port47and the cooling water outlet48and the sub-valve body43D is configured to open and close the cooling water bypass passage49.

As shown inFIGS. 7 and 8, the core piping51is configured to communicate the cooling water flow control unit41and the water pump30each other, and is provided to supply the cooling water having cooled the engine12to at least one of the water pump30and the radiator33. That is, the water pump30, the radiator33, the cooling water flow control unit41and the core piping51form an engine cooling water circulation structure configure to circulate the cooling water for cooling the engine12.

As shown inFIG. 7, the core piping51has a cylinder outlet hose52, a water pump inlet hose53, a radiator inlet hose54and a radiator outlet hose55. In the meantime, each of the hoses52to55is formed of a synthetic resin having flexibility, or the like, for example.

As shown inFIG. 8, the cylinder outlet hose52(first core piping) is connected between an outlet (not shown) of the water jacket and the first cooling water inlet44of the cooling water flow control unit41. The cylinder outlet hose52is provided to supply the cooling water having cooled (having flown out from the water jacket) the engine12to the cooling water flow control unit41.

The water pump inlet hose53(second core piping) is connected between the cooling water outlet48of the cooling water flow control unit41and the pump inlet31of the water pump30(refer toFIG. 7). The water pump inlet hose53is provided to supply the cooling water having passed through the cooling water flow control unit41to the water pump30.

The radiator inlet hose54(third core piping) is connected between the cooling water delivery port46of the cooling water flow control unit41and the radiator inlet37of the upper radiator34(refer toFIG. 7). The radiator inlet hose54is provided to supply the cooling water having passed through the cooling water flow control unit41to the radiator33.

The radiator outlet hose55(fourth core piping) is connected between the radiator outlet38of the upper radiator34and the cooling water return port47of the cooling water flow control unit41(refer toFIG. 7). The radiator outlet hose55is provided to supply the cooling water having passed through the radiator33to the cooling water flow control unit41.

The water pump inlet hose53, the radiator inlet hose54and the radiator outlet hose55are intensively disposed in a space between the engine12and the radiator33(refer toFIGS. 2 and 3).

As shown inFIGS. 8 and 9, the cooling piping61is configured to flow the cooling water delivered from the water pump30. The cooling piping61is provided to supply the cooling water having cooled the oil cooler26and the supercharger113to at least one of the water pump30and the radiator33. That is, the water pump30, the radiator33, the cooling water flow control unit41and the cooling piping61form a supercharger cooling water circulation structure configured to circulate the cooling water for cooling the oil cooler26and the supercharger113.

The cooling piping61is disposed at an inner side relative to a width (a length in the vehicle width direction) of the engine12in the right-left direction (refer toFIG. 9), as seen from the front, and is disposed at a rear side of the front end portion of the supercharger113(refer toFIG. 3), as seen from a side. That is, the cooling piping61is intensively disposed in a space between the engine12and the radiator33(refer toFIG. 3). In this way, the cooling piping61is intensively disposed near the front side of the engine12, so that it is possible to miniaturize the engine having the supercharger.

The cooling piping61includes a branched piping62, a first inlet piping63, a second inlet piping64, a first outlet piping65, a second outlet piping66, and a convergence piping67. In the meantime, the branched piping62, the first inlet piping63, the second inlet piping64, the first outlet piping65and the convergence piping67are preferably formed of a synthetic resin hose having flexibility, respectively, but may also be formed of a metallic pipe.

A tip portion of the branched piping62extending downward from the water pump30is branched, which are then connected to the first inlet piping63and the second inlet piping64. Specifically, an upstream end portion of the branched piping62is connected to the cooling water discharge port30B of the water pump30. A downstream end portion of the branched piping62is attached with an upstream-side triply branched pipe62A for splitting the flow of the cooling water into two flows.

The first inlet piping63is provided to supply the cooling water delivered (discharged) from the water pump30to the oil cooler26. The first inlet piping63is connected between one branched side of the upstream-side triply branched pipe62A and a right side surface of the oil cooler26.

The second inlet piping64is provided to supply the cooling water delivered from the water pump30to the supercharger113. The second inlet piping64is connected between the other branched side of the upstream-side triply branched pipe62A and the bearing unit116of the supercharger113. That is, the second inlet piping64is disposed in parallel with the first inlet piping63. Specifically, the second inlet piping64extends leftward from the upstream-side triply branched pipe62A and is disposed above the oil cooler26and the oil filter25. A downstream end portion of the second inlet piping64is connected to a lower inlet pipe116A protruding from a lower surface of the bearing unit116.

An inner diameter of the branched piping62is made greater than an inner diameter of the first inlet piping63and an inner diameter of the second inlet piping64.

The first outlet piping65is provided to return the cooling water having cooled the oil cooler26to the water pump30. The first outlet piping65extends obliquely in a right-upper direction from the right upper side surface of the oil cooler26.

The second outlet piping66is provided to return the cooling water having cooled the supercharger113to the water pump30. The second outlet piping66has a supercharger outlet pipe66A and a supercharger outlet hose66B. In the meantime, preferably, the supercharger outlet pipe66A is formed of metal or the like, and the supercharger outlet hose66B is formed of a synthetic resin or the like. However, the entire second outlet piping66may also be formed of a metallic pipe or a synthetic resin hose.

An upstream end portion of the supercharger outlet pipe66A is connected to an upper outlet pipe116B protruding from an upper surface of the bearing unit116. The supercharger outlet pipe66A extends upward from the bearing unit116of the supercharger113and is then bent rightward. The supercharger outlet pipe66A passes between the supercharger113and the exhaust pipe131(passes the rear of the exhaust pipe131) and then extends rightward. The supercharger outlet hose66B is connected between a downstream end portion of the supercharger outlet pipe66A and a downstream-side triply branched pipe67A (which will be described later). The first outlet piping65and the second outlet piping66are disposed in parallel with each other and converge at the right of the engine12and above the oil cooler26and the supercharger113.

The convergence piping67is configured to converge the first outlet piping65and the second outlet piping66and is connected to the cooling water flow control unit41. An upstream end portion of the convergence piping67is attached with the downstream-side triply branched pipe67A for converging the first outlet piping65and the second outlet piping66. The downstream-side triply branched pipe67A is disposed above the water pump30and at the rear of the water pump inlet hose53. The convergence piping67extends obliquely in the left-upper direction from the downstream-side triply branched pipe67A. The convergence piping67passes above the exhaust pipe131and extends in the left direction of the engine12. That is, the convergence piping67is provided to be gradient upward from the right side of the engine12toward the left side. A downstream end portion of the convergence piping67is connected to the second cooling water inlet45of the cooling water flow control unit41(refer toFIG. 8). That is, the convergence piping67is configured to communicate with the core piping51via the cooling water flow control unit41.

The first outlet piping65is connected between the oil cooler26and one branched side of the downstream-side triply branched pipe67A. The second outlet piping66is connected between the bearing unit116of the supercharger113and the other branched side of the downstream-side triply branched pipe67A. An inner diameter of the convergence piping67is made greater than an inner diameter of the first outlet piping65and an inner diameter of the second outlet piping66.

Herein, the flow of the cooling water is described. When the engine12starts, the water pump30also starts. The cooling water is delivered from the water pump30(supply part30A) to the water jacket of the engine12, thereby cooling the cylinder14and the cylinder head15. As shown inFIG. 8, the cooling water used for cooling the engine12passes through the cylinder outlet hose52and is then introduced into the first cooling water inlet44of the cooling water flow control unit41(left housing42L).

Also, as shown inFIGS. 8 and 9, when the water pump30starts, the cooling water is discharged from the cooling water discharge port30B of the water pump30, flows through the branched piping62and is then split into the first inlet piping63and the second inlet piping64. The cooling water flowing through the first inlet piping63is supplied to the oil cooler26to cool the engine oil. On the other hand, the cooling water flowing through the second inlet piping64is supplied to the supercharger113to cool the turbine unit114and the like.

The cooling water used for cooling the oil cooler26(engine oil) flows through the first outlet piping65, and the cooling water used for cooling the supercharger113flows through the second outlet piping66. The cooling waters flowing through the respective outlet pipings65,66converge in the downstream-side triply branched pipe67A, which then passes through the convergence piping67and is then introduced into the second cooling water inlet45of the cooling water flow control unit41(left housing42L). The cooling waters having flown out from the oil cooler26and the supercharger113converge with the cooling water having flown out from the engine12in the left housing42L. The first outlet piping65and the second outlet piping66are made to converge at the convergence piping67, so that it is possible to unify the communication destinations with the core piping51via the cooling water flow control unit41.

Herein, the thermostat43of the cooling water flow control unit41is configured to control the flow of the cooling water in accordance with the temperature of the cooling water introduced into the thermostat housing42.

As shown inFIG. 8, when the temperature of the cooling water is equal to or lower than a predetermined reference temperature T1(for example, just after the engine12starts), for example, the main valve body43B is seated on the valve seat43A, and the sub-valve body43D is separated from the sub-valve body43E. That is, the thermostat43completely closes the flow passage between the cooling water return port47and the cooling water outlet48and completely opens the cooling water bypass passage49. At this time, the cooling water introduced from each of the cooling water inlets44,45passes through the cooling water bypass passage49without flowing in the radiator33and is then introduced into the right housing42R from the left housing42L. The cooling water passes through the water pump inlet hose53from the cooling water outlet48and is then introduced into the pump inlet31of the water pump30. In this way, the cooling water to flow toward the radiator33is regulated, so that it is possible to efficiently perform a warm-up operation of the engine12.

Also, when the temperature of the cooling water is higher than the predetermined reference temperature T1and is equal to or lower than a predetermined reference temperature T2(T2>T1), for example, the main valve body43B moves in a direction of separating from the valve seat43A and the sub-valve body43D moves in a direction of sitting on the sub-valve seat43E as the temperature of the cooling water increases. That is, as the temperature of the cooling water increases, the thermostat43increases an area of the flow passage between the cooling water return port47and the cooling water outlet48and reduces an area of the cooling water bypass passage49. At this time, the cooling water introduced from each of the cooling water inlets44,45is split into a flow facing toward the radiator33and a flow facing toward the cooling water bypass passage49in the left housing42L. In the meantime, as the temperature of the cooling water increases, an amount of the cooling water flowing in the radiator33increases, as compared to an amount of the cooling water flowing in the cooling water bypass passage49.

Specifically, the cooling water in the left housing42L flows in the radiator inlet hose54from the cooling water delivery port46and is then introduced into the upper radiator34from the radiator inlet37(refer toFIG. 2). A part of the cooling water is cooled by the upper radiator34, flows in the radiator outlet hose55from the radiator outlet38(refer toFIG. 3), and is then introduced into the right housing42R from the cooling water return port47. The remaining of the cooling water introduced into the upper radiator34is supplied to the lower radiator35through one connecting hose36and is cooled by the lower radiator35. The cooling water cooled by the lower radiator35returns to the upper radiator34through the other connecting hose36, and is introduced into the right housing42R through the radiator outlet38and the like.

In the meantime, the cooling water having flowed in the cooling water bypass passage49converges with the cooling water having flowed in the radiator33inside the right housing42R, which then returns to the water pump30(pump inlet31) through the cooling water outlet48and the like.

Also, for example, when the temperature of the cooling water is higher than the reference temperature T2, the main valve body43B is separated from the valve seat43A, and the sub-valve body43D is seated on the sub-valve seat43E. That is, the thermostat43completely opens the flow passage between the cooling water return port47and the cooling water outlet48and completely closes the cooling water bypass passage49. At this time, the cooling water introduced into the left housing42L from each of the cooling water inlets44,45flows in the radiator33without flowing in the cooling water bypass passage49and returns to the water pump30(pump inlet31) from the inside of the right housing42R.

In the meantime, the sub-valve body43D and the sub-valve seat43E of the thermostat43may be omitted. However, when the thermostat43having the sub-valve body43D and the like is adopted, like the illustrative embodiment, it is possible to appropriately completely close the cooling water bypass passage49. Thereby, it is possible to enable the cooling water in the left housing42L to flow toward the radiator33without leaking the same to the cooling water bypass passage49. Also, since the thermostat43having the sub-valve body43D is greater than a thermostat having no sub-valve body43D, the cooling water bypass passage49having the thermostat43accommodated therein is also enlarged. Thereby, since a flowing resistance of the cooling water passing through the cooling water bypass passage49is reduced, it is possible to rapidly perform the warm-up operation.

According to the motorcycle1of the illustrative embodiment as described above, the oil cooler26(engine oil) is cooled by the cooling water supplied through the first inlet piping63. The supercharger113is cooled by the cooling water supplied through the second inlet piping64. Since the first inlet piping63and the second inlet piping64are disposed in parallel, the cooling water necessary for cooling of the oil cooler26and the cooling water necessary for cooling of the supercharger113are separately supplied. Also, the oil cooler26and the supercharger113are supplied with the cooling water from the water pump30, which has not been used for other cooling. Thereby, it is possible to appropriately cool the oil cooler26and the supercharger113.

Also, according to the motorcycle1of the illustrative embodiment, since the inner diameter of the branched piping62is made greater than the inner diameters of the respective inlet hoses63,64, it is possible to sufficiently secure the flow rates of the cooling water before the cooling water is split into the respective inlet hoses63,64. Thereby, it is possible to sufficiently supply the cooling water to the oil cooler26and the supercharger113(bearing unit116).

Also, according to the motorcycle1of the illustrative embodiment, since the inner diameter of the convergence piping67is made greater than the inner diameters of the respective outlet pipings65,66, it is possible to enable the cooling water to smoothly flow from the respective outlet pipings65,66to the convergence piping67. Thereby, it is possible to improve cooling performances of the oil cooler26and the supercharger113.

In the meantime, when the water pump30stops as the engine12stops, for example, the cooling water flowing through the cooling piping61also stops. Thereafter, the cooling water is heated at the oil cooler26or the supercharger113, thereby generating water vapor. Regarding this, in the illustrative embodiment, the convergence piping67is connected to the cooling water flow control unit41(circulation path) positioned above the oil cooler26and the supercharger114. The cooling water flow control unit41is disposed at the highest position of the flowing path of the cooling water. For this reason, the generated water vapor smoothly moves downstream through the respective outlet pipings65,66and the convergence piping67. Then, the cooling water upstream of the supercharger113is pushed toward the supercharger113by a pressure equilibrium action between the supercharger113and the cooling piping61. Thereby, the cooling water is supplied to the oil cooler26and the supercharger113, so that even after the engine12stops, it is possible to continuously cool the oil cooler26and the supercharger113. Also, it is possible to prevent seizing of a bearing configured to pivotally support the crankshaft and deterioration of the engine oil.

Also, the cooling water used for cooling of the engine12, the oil cooler26and the supercharger113is collected to the cooling water flow control unit41and is then cooled by the radiator33. Thereby, it is possible to stabilize the temperature of the cooling water, which is to pass through the radiator33and to be supplied to the engine12.

In the illustrative embodiment, the convergence piping67is connected to the cooling water flow control unit41. However, the disclosure is not limited thereto. For example, the convergence piping67may also be connected to the water jacket of the engine12and other piping (a hose, a pipe, a branched piping and the like), which serve as the circulation path.

In the illustrative embodiment, the disclosure is applied to the motorcycle1. However, the disclosure is not limited thereto. For example, the disclosure can also be applied to a saddle-ridden type vehicle (for example, a three-wheeled vehicle with two front wheels and one rear wheel) having the same structure.

In the meantime, the illustrative embodiment relates to one aspect of the saddle-ridden type vehicle of the disclosure, and the technical scope of the disclosure is not limited to the illustrative embodiment. The constitutional elements of the illustrative embodiment can be appropriately replaced or combined with the existing constitutional elements and the like. Also, the illustrative embodiment is not construed to limit the inventions defined in the claims.