TW201016492A - Forced air-cooled vehicle engine unit, and motorcycle - Google Patents

Abstract

To provide a forced air-cooled vehicle engine unit which has a simple construction, higher layout flexibility in a vehicle and higher fuel combustion efficiency, and to provide a motorcycle including such an engine unit. An auxiliary air intake passage defining member 41 is connected to an air intake pipe 36 connected to a cylinder head 23. The auxiliary air intake passage defining member 41 defines an auxiliary air intake passage K1. The auxiliary air intake passage K1 is branched from a main air intake passage P1 in the air intake pipe 36 to guide intake air into a space defined adjacent to an injection nozzle of an injector at least during idling. At least a part of the auxiliary air intake passage defining member 41 is located outside a shroud 50. A portion around the injection nozzle is cooled by an assist air from the auxiliary air intake passage K1 during idling. A portion around the injection nozzle is cooled by cooling wind generated by a fan 56 during the traveling of a vehicle.

Description

201016492 Sixth Invention: TECHNICAL FIELD The present invention relates to a forced air-cooled engine unit and a locomotive for a vehicle. [Prior Art] In the engine disclosed in Patent Document 1, a main intake passage for conveying air from the air cleaner to the combustion chamber of the engine is provided. Autonomous intake passage; expenditure secondary intake passage. The injector is mounted on the cylinder head of the engine. In the sub-= gas passage, at least during idling, the intake of the 丨 autonomous intake passage is: auxiliary air flow. The auxiliary air is blown toward the granules injected by the ejector to promote micronization. Thereby, the combustion efficiency of the fuel at least during idling is improved. Patent literature! The engine described is a natural air-cooled engine that allows the engine to be blown to the 51 engine. This allows the engine to be cooled by the traveling wind. In general, a cold engine or a water-cooled engine is known as an engine used in a vehicle such as a locomotive. The air-cooled engine blows air to the engine: Allows the engine to cool. Therefore, the air-cooled 5 丨 engine has no water-cooled engine radiator or cooling water pump, etc., so that the structure is simple. In the engine described in Patent Document 1, since the ejector is mounted on the cylinder head, the steam red cover and the ejector are cooled by the wind. thus

The generation of a vapor seal for the fuel supplied to the injector increases the combustion efficiency. Promote atomization, which can be, however, patent literature! The engine described is a natural air-cooled type. It must be placed at a position where the lamp is easy to blow. |Qing, so there is a problem with the low degree of freedom of the engine configuration of the car 14i431.doc 201016492 t. In response to this, as described in Patent Document 2, 4 #^驮2, 6 has developed a type of forced air cooling: a wind that is driven by the rotation of the engine crankshaft and a cylinder head that covers the engine or A mask plate such as a steam rainbow body. The wind generated by the fan passes through the inside of the mask and is blown toward the human "J, the flying cylinder or the cylinder block to cool the engine. In the forced air-cooled engine, the s# π $ field fan is used to configure One part of the engine inside the mask is cooled.

The forced air-cooled engine does not rely on the driving wind to cool the engine, so there is no need to configure the engine in such a way that the wind is blown to the engine. Therefore, the degree of freedom in engine configuration in the vehicle is high. [PRIOR ART DOCUMENT] [Patent Document 1] [Patent Document 1] Patent Publication No. WO2005/09823A No. [Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-241326 [Summary of the Invention] [Problems to be Solved by the Invention] As described above, the natural air-cooled engine described in Patent Document 1 can promote the atomization of the fuel by the auxiliary working gas, so that the combustion efficiency of the fuel is high. However, it is necessary to blow the wind to the engine, so the degree of freedom of configuration is low. Further, the forced air-cooled engine described in Patent Document 2 does not need to be disposed so that the traveling wind is blown to the engine, and the degree of freedom in the arrangement in the vehicle is high. Therefore, the engine is intended to be applied to an engine as described in the patent document, that is, an engine in which an ejector is attached to a cylinder head of an engine and an atomizing 141431.doc 201016492 is promoted by an auxiliary air, and is applied to Patent Document 2 Forced air-cooled engine. The reason for this is that it is possible to provide an engine which is highly efficient in fuel combustion 35 and has a high degree of freedom in arrangement in a vehicle. The present invention has been made in view of the above circumstances, and an object of the invention is to provide a forced air-cooled engine unit for a vehicle having a simple structure, a high degree of freedom of arrangement in a vehicle, and a high combustion efficiency of fuel, and a locomotive having the same. [Technical means for solving the problem] The forced air-cooled engine unit for a vehicle of the present invention includes: a bow engine body including a crankcase that houses a crankshaft, a cylinder block that reciprocally accommodates a piston connected to the crankcase, and a steam red cover, the cylinder head forms a combustion chamber together with the cylinder block, and forms a main intake passage-partial portion-intake pipe connected to the combustion chamber, which is connected to the cylinder head and is coupled to the cylinder Forming the main air intake passage; the mask plate covering at least the portion of the steam cover; the fan 'disposed between the cover plate and the engine portion' is driven by the rotation of the crankshaft for use a cooling air of the cooling body; a throttle body having two air-closing valves arranged at intervals in a flow direction of the intake pipe-shaped rolling, and a part of the air intake pipe formed and 々# The body, and the above-mentioned two, that is, the tube between the two, that is, the right side of the above-mentioned mask; and the fuel spray f on the above-mentioned cover, having the above-mentioned road to the above-mentioned steam jet mouth. In the case of the daily transportation of the milk passage, the forced air-cooled engine unit for the vehicle includes a passage forming body that forms an auxiliary air intake passage, and the auxiliary air intake passage and the two throttle valves are connected from the top to the bottom. The milk passage knife is supported, and at least the air is guided to the space near the nozzle nozzle J41431.dc 201016492 formed on the steam red cover. At least the inner gas passage connecting the masks is formed. One of the surrounding portions of the auxiliary air intake passage, and a space between the shape and the space outside the mask plate. [Effects of the Invention] According to the present invention, it is possible to provide a simple structure, high degree of freedom, and high fuel combustion efficiency. Vehicle unit and locomotive with it. [Embodiment]

<Completion Process of the Invention of the Invention> (1) The inventors of the present invention have studied the case where an engine that mounts a mouthpiece on a cylinder head and that promotes atomization of fuel by assisting air is applied to the forced air-cooled plum. Thus, an engine having a high combustion efficiency of fuel and a high degree of freedom in arrangement in a vehicle can be realized.

In the case of a forced air-cooled engine (7), a forced air-cooled engine is provided with a sub-intake passage. This is a configuration in which the auxiliary air that has passed through the auxiliary air intake passage is blown to the fuel injected from the injector. In the forced air-cooled engine, the mask plate covers the engine body including the cylinder block and the like. Moreover, the air is introduced into the mask by a fan disposed in the mask, and air is allowed to flow in the mask, thereby cooling the engine body. Therefore, it is desirable to cover as many engine bodies as possible with a mask. However, after covering the engine body with the mask plate, the heat of the engine body easily fills the periphery of the mask plate, with the result that the periphery of the injector is easily at a high temperature. When the periphery of the injector becomes high temperature, bubbles are generated in the fuel supplied to the injector. As a result, a steam seal or breathing is generated, so that the combustion efficiency of the fuel is lowered. Further, in an engine which is easily covered with heat by being covered by a mask, even if only the auxiliary air intake passage is provided, the auxiliary air passage and the auxiliary air passing through the inside thereof reach a high temperature. As a result, the mixture of the injected fuel and the auxiliary air reaches a high temperature, and correspondingly, the oxygen concentration becomes low, so that the combustion efficiency of the fuel is lowered. Since the fan rotates together with the crankshaft provided in the engine body, the speed of the fan is also reduced when idling. Therefore, there is a problem that the cooling performance of the fan at the time of idling is lowered, and the inside of the mask plate is easily filled with heat from the engine body. The inventor of the case focused on the above situation. (3) The inventor of the present invention considered the vehicle separately from the time of idling. That is, it is found that the performance of the cooling fuel injection device can be improved when the vehicle is traveling and idling, respectively. (A) When the vehicle is running, the auxiliary air intake passage to which the injector as the fuel injection device is cooled is separated from the shield plate, and the injector or the auxiliary air intake passage can be first used when the vehicle is running. By turning, it is expected that the inside of the fan can be expected to flow to the outside. Thereby the cooling of the injector is improved. The fan is cooled at a high speed together with the crankshaft. In order to utilize the cooling of the fan, the structure of the injector or the arrangement is considered. Near the root, the air is removed from the mask. The cooling wind of the fan can be used. (B) When the vehicle is idling. Secondly, the idling is performed when idling. In the case of idling, since the crankshaft and the fan rotate at a low speed, the helmet method ^ ^ ^ Α ... is expected to cool the fan. However, in order to improve the combustion efficiency of the fuel, a feed passage is adopted, and the auxiliary intake passage 141431.doc 201016492 branches the autonomous intake passage, and guides the intake (auxiliary air) to the steam red cover at least during idling. Form the space near the nozzle of the mouth. In this way, the structure of the auxiliary hole and the work hole is adopted. In this configuration, attention is paid to the auxiliary air-cooled injector supplied from the auxiliary air intake passage when idling is available. Thereafter, a configuration in which the throttle body to which the auxiliary air intake passage is connected is disposed outside the mask is considered. Thereby, at least the upstream side of the sub-intake material is hard to be affected by the heat in the mask. Therefore, the passage through the auxiliary air intake passage can be suppressed

The temperature of the intake air rises to allow the injector to be cooled during idling. The inventor of the present invention completed the invention of the present invention by the process as described above. <Embodiment 1>, Lower > Schematic, an embodiment in which the present invention is embodied will be described. In addition, in the following description, the front, the top, the bottom, and the left and right sides of the locomotive are in a positional attack that is equivalent to a state in which the locomotive is in a horizontal position, and the viewpoint of the driver when the driver is facing the side is used as a reference. Moreover, in each figure, the arrow indicates the direction in front of the locomotive. Similarly: in each figure, 'α arrow B indicates the direction behind the locomotive, arrow indicates the direction above the locomotive, arrow 〇 indicates the direction under the locomotive, arrow U indicates the left direction of the locomotive' and is indicated by the arrow R The right direction of the locomotive. Fig. 1 is a right side view of a locomotive 200 according to a first embodiment of the present invention. In Fig. i, the portion of the locomotive 200 is cut off. In the present embodiment, the locomotive_ is a small-turbine treadmill. In addition, in the present embodiment, the small-turbine treadmill is a pure locomotive of the present invention, but the invention is not limited thereto. In addition to the small turbine treadmill, the present invention can also be applied to other locomotives such as a so-called motorcycle (m〇torcycle), a light-duty treadmill (m〇ped), and an off-road vehicle (heart 141431.doc 201016492 road bike). The front portion of the 200 is provided with a handle 10. The handle 10 is coupled to the front wheel 14 via a steering shaft 13 that is inserted into a head pipe U. The frame body 15 is coupled to the front tube 11. The frame body 15 The whole body is extended in the front-rear direction of the vehicle. The four end portions of the frame body 15 are coupled to the front tube. At the rear of the frame body 15, the ampoule has a seat 16. In the frame body 15, it is more than the seat 16 A footrest I7 is attached to the front. The footrest 17 is located below the seat 16. Further, a body cover 18 is attached to the frame body 15. The body cover 18 is from the footrest 17 The erection of the part upwards surrounds the space G1 below the seat 16 〇 Figure 2 is shown in an enlarged right side view, The body cover 18 is formed to surround the lower space G1 of the seat 16. The body cover μ includes a front wall 2〇2 disposed below the front end of the seat 16, and a right end and a left end disposed at the seat μ. A pair of side walls 203 below the portion. In Fig. 2, only the right side wall 2〇3 of the pair of side walls 203 is illustrated. The pair of side walls 2〇3 are formed bilaterally symmetrically. - on the frame body 15 The Swing Unit type engine unit 20 is installed. The engine unit 20 is a forced air-cooled engine unit. The engine unit 20 is partially covered by the vehicle body cover 18. Specifically, the engine unit 20 is described later. The front end side of the W-gen body and the front end side of the mask plate 5〇 are covered by the vehicle body cover 18. The best of the engine unit 2 includes: an engine body η, a gas S36, that is, a valve body 38, The auxiliary air intake passage forming body 々I and the mask plate 14] 43l.doc 201016492 are disposed behind the body cover engine body 21 behind the front wall 202 of the lower space G1 of the seat 166. Fig. 3 is an engine unit 2 〇 _ phase 八 a ^ knife profile, showing the state observed in the engine unit 20 Also, g卩_I7' represents a horizontal section of a portion of the engine unit 20. The A* axes of the engine body 21 and Ai® 1 are oriented toward the front and rear direction XI of the vehicle. The engine body 21 is a single cylinder four strokes. The engine body 21 is provided with a cylinder block 22, and the body is mounted on the cylinder block 22 (5)

The cylinder head 23 on the (1)% portion; and the crankcase μβ to the crankcase 24 mounted on the rear end portion of the cylinder block 22 constitute the rear end portion of the engine body 21. In the crankcase 24, there is a crankshaft 57 extending toward the left-right direction Yi of the vehicle. The crankshaft 57 is rotatably supported by the crankcase 24 via bearings 282. The right end 204 of the crankshaft 57 projects from the right side face 246 of the crankcase 24. A fan 56 is rotatably coupled to the right end portion 2〇4 of the crankshaft. The fan (10) is driven by the rotation of the crankshaft 57. To cool the engine body 21, the fan empties air from the mask 50. The outer bow is turned to the inside, and the air is introduced into the middle portion of the crankshaft 57 as a cooling wind, and the large end portion of the connecting rod (10) is connected. The cylinder block 22 is connected to the front end of the crankcase 24 The space in the cylinder block 22 is regarded as a vapor red chamber E in the cylinder chamber m, and the piston 2〇8 is accommodated in a reciprocating manner along the vapor red axis. The piston 208 is coupled to the piston pin 29 via the piston pin 29. The small end of the connecting rod 205. The cylinder head 23 is connected to the front end surface of the cylinder block 22 to constitute the front end of the engine body 21. In the cylinder head 23, it is accommodated to drive the intake valve (not shown) 141431.doc • 13 · 201016492 and the camshaft 209 of the exhaust valve 31. As shown in Fig. 1, the crankcase 24 and the frame body 15 are coupled via a pivot 25. The axis of the pivot sleeve 25 extends in the left and right direction of the vehicle γι. The rear portion of the unit 2 is attached to the rear wheel 27 via the power transmission unit 26. Again, A rear shock absorber (γ "γ shock abS〇rber" 28 is attached between the rear portion of the power transmission portion 26 and the rear portion of the frame body 15. According to this configuration, the engine unit 2 and the rear wheel 27 are swingable in the vertical direction with respect to the frame body 15 with the pivot 25 as the swing center. Fig. 4 is a longitudinal sectional view of a main portion of the engine unit 20, showing the state of the engine unit 20 as viewed from the right side. The space between the piston 29, the cylinder block 22, and the cylinder head 23 housed in the cylinder block 22 is a combustion chamber A1 in which the mixed gas is combusted. The cylinder head 23 is provided with an intake valve 210 opposed to the combustion chamber A1 and the above-described exhaust valve. Fig. 5 is a right side view of the engine unit 20, showing a part of it cut off, and a part of it is represented by an imaginary line, that is, a two-dot chain line. Referring to Fig. 4 and Fig. 5, a tubular shape is provided on the right side surface of the cylinder head 23! Sleeve 32. The first sleeve 32 is integrally formed with the cylinder head 23. The first sleeve 32 protrudes from the cylinder head 23 toward the outer side of the mask 50. The first! One of the front end sides of the sleeve 32 is located on the outer side of the mask 50 and is exposed from the mask 50. The inner space of the first sleeve 32 communicates with the main intake passage ρ, which will be described later, around the intake valve 210. An injector 34 as a fuel injection device is attached to the first sleeve 32 via a synthetic resin holder 33. Since the injector 34 is attached to the vapor red cover 23, it is located at the front end of the engine body 21. Referring to Fig. 4, the holder 33 includes a cylindrical portion 211 and a crotch portion 212 provided at the base end of the cylindrical portion 211. The crotch portion 212 abuts against the front end of the first sleeve 32. By 141431.doc -14- 201016492 ‘this’ positions the holder 33 relative to the first sleeve 32. The cylindrical portion 211 is housed in the accommodating space H1 formed inside the first sleeve 32. The outer peripheral surface of the base end portion 213 of the cylindrical portion 2丨i and the inner peripheral surface of the i-th sleeve 32 are fluid-tightly sealed by the first sealing member 214 such as a ring-shaped ring. Between the outer peripheral portion of the cylindrical portion 211 and the inner peripheral surface of the first portion 215 and the inner peripheral surface of the first sleeve 32, a cavity G2 which is an annular gap is formed. The front edge of the front portion 216 of the cylindrical portion 211 is fitted to the inner circumferential surface of the i-th sleeve 32 with substantially no gap. The inner space of the front end portion 216 of the cylindrical portion 211 is taken as the space near the nozzle 35 of the ejector 34, that is, the ejection space (7). The injection space (7) is formed in the cylinder head 23, and communicates with the combustion chamber A via the intake valve 21 to the front end portion 216 of the cylindrical portion 211, and a plurality of through holes 217 are formed. The through holes 217 are formed in plural (e.g., four) at equal intervals in the circumferential direction of the front end portion 216 of the cylindrical portion 211. The chamber G2 communicates with the ejection space G3 through the through hole 217. The injection benefit 34 system injects fuel from a fuel tank (not shown) to the intake passage. The injector 34 includes an injector body 218 having an elongated shape and a spray nozzle 35 disposed at the front end of the injector body 218. The injector body 218 is inserted into the cylindrical portion 211 of the holder 33 and held by the holder 33. The outer circumferential surface of the injector body 218 and the inner circumferential surface of the holder 33 are used. The second sealing member 219 such as a ring is sealed in a liquid-tight manner. The injection nozzle 35 is opposed to the radiant space G3 and is disposed in the main intake passage via the cylinder head 23. 1 is directed to the direction in which the fuel is injected into the intake valve 21〇. The timing at which the injector 34 fires the fuel to the intake valve 210 is shown by an ecu (also referred to as an Engine C〇ntrol Unit' engine control unit; m. 〇心(五)(4) 141431.doc 15 201016492

The intake pipe 36 is controlled by a control device such as a unit 'electronic control unit', and includes an intake hose 37 that is connected to the air cleaner (not shown) and extends forwardly; The cylindrical tubular body 22〇 at the distal end portion of the intake hose-37; and a connecting pipe 39 connected to the front end portion of the tubular body 22〇 and bent downward. A cylindrical intake port 221 is formed on the cylinder head 23'. The main intake passage on the cylinder body 21 is formed by the intake port 221! ^. An intake valve 210 is disposed at one end of the intake port 221, and the other end of the intake port 221 is open to the upper surface of the cylinder head 23. The other end of the intake port 221 is formed by a flange 222 formed on the cylinder head 23. The flange 222 faces the flange 223 formed at the front end portion of the connecting pipe 39, and is fixed by a fixing screw (not shown). By this, the intake port 221 is connected to the front end portion of the connecting pipe 39 (i.e., the downstream end of the intake pipe 36). The main intake passage P1 is formed by the intake port 221 of the cylinder head 23 and the intake pipe 36. The throttle body 38 includes the above-described tubular body 220, and a first throttle valve 40A and a second throttle valve 40B as two throttle valves. The axis of the cylindrical body 220 extends in the front and rear direction XI of the vehicle auxiliary. The tubular body 220 is disposed above the cylinder block 22 of the engine body 21. Further, the care body 220 is disposed above the upper wall 243 of the tubular portion 51 of the mask plate 5A. Thereby, the entire throttle body 38 is disposed on the outer side of the mask plate 50. The first damper valve 40A and the second throttle valve 40B open and close the main intake passage P1 on the intake pipe %, respectively. The i-th throttle valve 4A and the second throttle valve 40B are disposed at intervals of the flow direction 〇1 of the intake air in the main intake passage Pi, and are disposed at 141431.doc -16 - 201016492. The first throttle valve 40A and the second throttle valve 40B are housed in the tubular body 22A. The first throttle valve 4A is disposed on the downstream side of the second throttle valve 40B in the flow direction C1 of the intake air. That is, in the main intake passage p, the i-th throttle valve 40A is located between the second throttle valve 40B and the cylinder head 23. The first throttle valve 4A and the second throttle valve 40B are each formed in a disk shape. The first throttle valve 40A is supported by a first rotating shaft 224 that extends orthogonally to the central axis of the tubular body 220. The second throttle valve 40B is supported by a second rotating shaft 225 that extends orthogonally to the central axis of the tubular body 22A. Figure 6 is a diagrammatic right side view of the throttle body 38. Referring to Fig. 6, the second rotation shaft 224 and the second rotation shaft 225 are rotatably supported by the cylindrical body 220, respectively. By the rotation of the first rotating shaft 224, the first throttle valve 4A is rotated integrally with the first rotating shaft 224 around the i-th rotating shaft 224. Similarly, the second throttle valve 225 rotates around the second rotation shaft 225 to rotate integrally with the second rotation shaft 225 by the rotation of the second rotation shaft 225. A drive wheel 226 is rotatably coupled to the second shaft 225. A throttle cable (not shown) is attached to the drive wheel 226. Thereby, the drive wheel 226 rotates in conjunction with the driver's throttle operation. The second rotating shaft 225 is rotated by the rotation of the driving wheel 226 to open and close the second throttle valve 4A. The opening and closing operation of the second throttle valve 40B and the opening and closing operation of the i-th throttle valve 4A are associated with the cup coupling mechanism 227. That is, the seventh throttle valve 4A and the second throttle valve 40B are interlocked. The link mechanism 227 has a so-called ineffective motion structure, and the time when the i-th throttle valve 4A starts to open is later than the second throttle valve 4〇B starts to be actuated 141431.doc -17- 201016492. The link mechanism 227 includes a first main link member 228 and is disposed in the first! The second main link member 229, the sub-link member 230, and the rotation transmitting member 231 on the rear side of the main link member 228. The second main link member 229 is a small piece member formed integrally with the drive wheel 226. The second main link member 229 is rotatable about the second rotation shaft 225. The second main link member 229 is rotatably coupled to the sub-link member 230 via the second connecting shaft 232. The sub-link member 230 is a rod-shaped member that is long in the vehicle longitudinal direction XI, and the second main link member 229 is associated with the first main link member 228. A second connecting shaft 232 is disposed at the rear end of the sub-link member 230. The front end of the sub-link member 230 is coupled to the first main link member 228 so as to be rotatable relative to each other via the first connecting shaft 233. The first main link member 2 2 8 is an elongated member formed of a metal plate. The first end of the first main link member 228 is coupled to the first connecting shaft 233. The intermediate portion of the first main link member 228 is coupled to the first rotating shaft 224 so as to be rotatable relative to each other. Thereby, the first main link member 228 can be rotated independently of the first rotating shaft 224. At the rear end of the first main link member 228, a pressing member 234 is provided. The distance from the center axis J1 of the second rotating shaft 225 which is the swing center of the second main link member 229 to the center axis J2 of the second connecting shaft 232 is only a distance D2. Further, the distance from the central axis of the first rotating shaft 224 which is the swing center of the i-th main link member 228 to the central axis 14 of the i-th connecting shaft 233 is only a distance D1. Between the distances d 1 and D2, the relationship of D2 > D 1 is established. 141431.doc -18- 201016492 The rotation transmitting member 23 1 is a member formed of a metal plate. The rotation transmitting member 23 1 is rotatably coupled to the first rotating shaft 224. A pressed portion 235 that can abut against the pressing member 234 is formed on the rotation transmitting member 23 1 . When the second throttle valve 40B is in the fully closed state, the pressing member 234 and the pressed portion 235 are spaced apart from each other in the circumferential direction of the first rotating shaft 224 by a predetermined interval. FIG. 4, the auxiliary air intake passage forming body 41 It is extended from the tubular body 220 of the throttle body 38 and formed to the cylinder head 23! Until the sleeve 32. The entire auxiliary air intake passage forming body 41 is disposed on the outer side of the mask plate 5A. The auxiliary air intake passage forming body 41 forms an auxiliary air intake passage κι. The first sleeve 32 is formed integrally with the cylinder head 23. An injector 34 is mounted on the first sleeve 32. On the sleeve [32], a fourth sleeve 239 is integrally formed. The fourth sleeve 239 extends perpendicularly to the axis of the injector 34. A third sleeve 238 is attached to the fourth sleeve 239. The auxiliary air intake forming body 41 includes a second sleeve 236 fixed to the tubular body 22, a fourth sleeve 239 and an i-th sleeve 32 formed on the cylinder head 23, and disposed in the first sleeve 32. The cylindrical portion 211 of the holder 33; the third sleeve 238 attached to the fourth sleeve 239; and the hose 237 connecting the third sleeve 238 and the second sleeve. ★ The second sleeve 236 is a cylindrical member made of metal and formed in an L shape. The second sleeve = 36 is disposed on the upper side of the tubular body 22A. One of the 2% ends of the second sleeve constitutes a pair = the upstream end forming portion of the passage forming body 41. The upstream end forming portion 24'' is at one end between the first throttle valve 4GA and the second throttle valve housing, and is fixed to the tubular body 220. The auxiliary air intake passage in the second sleeve 236 constitutively forms the auxiliary air intake I4143I.doc 19 201016492 The upstream end K2 of the road K1 and communicates with the main intake passage pi. The hose 237 is a tube formed of rubber and other flexible materials. One end of the hose 237 is coupled to the other end of the second sleeve 236. One end of the third sleeve 238 is connected to the other end of the hose 237. The fourth sleeve 239 is formed integrally with the first sleeve 32. The fourth sleeve 239 and the first sleeve 32 are disposed such that their central axes are substantially orthogonal to each other. The fourth sleeve 239 is disposed on the outer side of the mask 50 with reference to Figs. 4 and 5'. The auxiliary air inlet passage κι and the first sleeve 32 of the other end of the hose 23 7 , the third sleeve 23 8 and the fourth sleeve 239

The inner chamber G2 and the through hole 217 of the cylindrical portion 211 constitute the auxiliary air intake passage and the downstream end K3. Downstream K3 series and the first! The spray space (7) in the sleeve 32 is connected. The other end of the third sleeve 238 is connected to the fourth sleeve 239. The downstream end forming portion 241 of the auxiliary air intake passage forming body is constituted by the other end of the hose 237, the third sleeve 238, the fourth sleeve 239, the first sleeve 32, and the cylindrical portion 211 of the retainer 33. The downstream end forming portion 241 is disposed on the outer side of the mask plate 5. In the first sleeve 32, the downstream end forming portion 241 is formed by being disposed outside the mask plate.

According to the above configuration, the upstream end of the auxiliary air intake passage K1 is formed by the upstream end forming portion 24 of the second casing, and is between the first air valve and the first air valve 40B and the main intake passage. Connected. Further, the downstream material of the auxiliary air intake passage K1 is formed by the downstream end forming portion 241. The downstream end K31 is in communication with the injection space G3. , '乍 is the auxiliary air independent air intake passage ρι flows into the auxiliary air intake 》. The auxiliary air passing through the auxiliary air intake passage K1 is guided to the injection air j. The auxiliary air supplied to the injection space G3 is blown toward the self-injector* 141431.doc • 20· 201016492 The fuel injected ‘ to promote the atomization of the fuel. Fig. 7 is a diagram showing the relationship between the opening degree of the first throttle valve 4A and the opening degree of the second throttle valve 4B. Furthermore, in Figure 7, the first! The opening degree of the throttle valve 4〇A is zero when it is idling. Similarly, the opening degree of the second throttle valve 40B is zero when it is idling. The solid line diagram in Fig. 7 shows the opening degrees of the first throttle valve 4A and the second throttle valve 40B in the present embodiment. As shown in the solid line diagram, when the opening degree of the second throttle valve 4〇B is 10 degrees or less, the opening degree of the i-th throttle valve 4A is maintained at a degree of twist. On the other hand, in Fig. 7, the broken line shows the case where the opening degrees of the first and second throttle valves are always the same because the invalid moving mechanism is not provided. As shown in the virtual line diagram and the solid line diagram, in the present embodiment, the second throttle valve 4A is opened later than the first throttle valve 40A. The operation of the i-th throttle valve 4A and the second throttle valve 40B will be described in further detail below with reference to FIGS. 6 and 7. The opening degrees of the first throttle valve 40A and the second throttle valve 40B are dependent on the load (throttle). The door operation amount is changed and controlled in the following manner. First, the i-th throttle valve 40A located on the downstream side of the flow direction of the intake air is maintained at the fully closed position from the no-load (slow speed) operation region to the specific partial load operation region. Specifically, the rotation of the drive wheel 226 accompanying the throttle operation of the driver is not transmitted to the first rotation shaft 224 but only to the second rotation shaft 225 until the partial load operation region. Therefore, only the second throttle valve 40B is opened and closed by the rotation of the second rotating shaft 225. At this time, the sub-link member 23A and the i-th main link member 228 operate in conjunction with the operation of the second main link member 229. Thereby, the first main link member 228 is rotated about the first rotating shaft 224 by 141431.doc -21 - 201016492. However, before the pressing member 234 of the first main link member 228 abuts against the pressed portion 235, the first rotating shaft 224 and the first throttle valve 40A are not rotated. Therefore, the amount of air flowing into the injection space G3 of the injection nozzle 直至 is controlled only by the opening degree of the second throttle valve 4〇b until the partial load operation region. In the partial load operation region, the auxiliary air flowing in the auxiliary air intake passage K1 is mixed with the fuel injected from the injection nozzle 35 in the injection space G3. Thereby, the atomization of the fuel can be promoted, and the fuel burning efficiency can be improved. Therefore, it is also possible to reduce the unburned fuel which is easily generated when the engine is cold-started. On the other hand, in the transition from the partial load region to the high load operation region, the i-th throttle valve 4A is opened in response to the throttle operation. Thereby, not only the auxiliary air passing through the auxiliary air intake passage K1 but also the intake air passing through the other end of the intake air 221 is introduced into the cylinder head 23. Specifically, referring to Figs. 7 and 8, when the transition from the partial load region to the high load operation region, the amount of rotation of the second main link member 228 based on the idling state exceeds a specific value. As a result, the pressing member 234 of the i-th main link member 228 abuts against the pressed portion 235 of the rotation transmitting member 231. Thereby, in conjunction with the rotation of the first main link member 228, the rotation transmitting member 231 and the first rotating shaft 224 are rotated, so that the first! The throttle valve 4〇a rotates. Thus, the air is introduced not only through the auxiliary air intake passage, but also through the connecting pipe (10). As described above, for the link mechanism 227, the distance D2 > the distance (1) results in 'in the high load operation region' the opening and closing speed of the ith throttle valve 141431.doc • 22 - 201016492 than the second throttle valve 40B The opening and closing speed is fast. As a result, when the second throttle valve 40B is fully opened, the first throttle valve 4A is also fully opened. Referring to Fig. 1, an exhaust pipe 43 connected to an exhaust valve of a cylinder head 23 and a muffler 44 connected to a rear end portion of the exhaust pipe 43 are attached to the engine body 21. The entire exhaust pipe 43 and the muffler 44 are singularly elongated in the longitudinal direction of the vehicle. The exhaust pipe 43 is disposed below the engine body 21 . The upper end portion (front end portion) of the exhaust pipe 43 is bent upward and connected to the lower surface of the cylinder head 23 to communicate with the exhaust passage near the exhaust valve. The rear end of the exhaust pipe 43 and the front end of the muffler 44 are connected to the rear end of the crankcase 24 at a position substantially the same as the rear end surface of the crankcase 24, and the muffler 44 extends rearwardly obliquely rearward of the rear wheel 27. Inside the muffler 44, a catalyst device (not shown) is housed. FIG. 9 is a plan view of the mask 50. Further, in Fig. 9, a part of the engine unit 20 is represented by an imaginary line, that is, a two-dot chain line. Referring to FIGS. 5 and 9', on the engine body 21, a mask plate 50 for cooling the engine body 21 is mounted. The mask plate 50 includes a cylindrical portion 51 that surrounds the entire cylinder 22' throughout the entire circumference and throughout A portion of the cylinder head 23, that is, the rear end portion 207 is circumferentially surrounded; the side plate portion 52' covers the crankcase 24 from the right side of the crankcase 24; and the protective pad 53. Further, the mask 50 is formed by combining two left and right half members 54L and 54R. The partition portion 51 is constituted by the entire left half member 54L and the rain end portion of the right half member 54R. Further, in the right half member 54R, the portion closer to the rear than the tubular portion 51 constitutes the side plate portion 52 and the guard 塾 141431.doc -23- 201016492 53 °. Referring to FIGS. 3 and 5, the tubular portion 51 is disposed in the The right side of the engine body 21 has a right wall 242 that bulges to the right side, and the right wall 242 covers a portion of the right side surface of the cylinder block 22 and the right side surface of the rear end portion 207 of the cylinder head 23. The right wall 242 bulges to the right side to the extent that the rear end is larger than the front end. In addition, as shown in FIG. 9 and the left side view of the main part of the engine unit 2, the cylindrical portion 51 further includes an upper wall 243 disposed above the engine body 21 and disposed on the left side of the engine body 21. The left wall 244. The upper wall 243 covers a portion of the upper surface of the cylinder block 22 and the upper surface of the rear end portion 207 of the cylinder head 23. The left wall 244 covers a left side of the cylinder block 22 and a portion of the left side south of the rear end portion 207 of the cylinder head 23. Further, the tubular body 22 is disposed substantially at the center of the engine body 21 in the left-right direction Y1 of the vehicle. Figure 11 is a bottom plan view of the main portion of the mask 50. Further, in Fig. u, a part of the engine unit 20 is represented by an imaginary line, that is, a two-dot chain line. Referring to Fig. 5 and Fig. 11, the cylindrical portion 5 further includes a bottom wall 245 disposed below the engine body 21. The bottom wall 245 covers a portion of the bottom surface of the cylinder block 22 and the bottom surface of the rear end portion 207 of the cylinder head 23. 3 and 5, the side plate portion 52 includes a main plate portion 247 that faces the fan 56 via the right side surface 246 of the crankcase 24 in the vehicle left-right direction Y1, and a peripheral edge of the autonomous plate portion 247. An arc-shaped arcuate plate portion 248. The main plate portion 247 covers the right side surface 246 of the crankcase 24 from the right side. The front end of the main plate portion 24 7 is connected to the right wall 242 of the cylindrical portion 51. The arcuate plate portion 248 is formed in an arc shape. The arc-shaped plate portion 248 is a self-supporting plate 141431.doc •24-201016492 247 extends to the right side surface 246 of the crankcase 24, and is adjacent to the right side surface 246 of the crankcase 24 via the third sealing member 249. The arcuate plate portion 248 is fixed to the crankcase 24 by a fixing screw (not shown). Referring to Fig. 3, a front space M1 is formed between the outer circumferential surface of the cylinder block 22 and the outer circumferential surface of the rear end portion 207 of the cylinder head 23 and the inner circumferential surface of the tubular portion 51. Further, a rear space M2 is formed between the inner surface of the side plate portion 52 and the right side surface 246 of the crankcase 24. The cooling air passage M3 through which the cooling air of the fan 56 passes is formed by the front space M1 and the rear space M2. A portion of the cooling air passage M3 is located between the front end of the mask 50 and the rear end 207 of the cylinder head 23. At the front end of the front space M1, a portion of the front end portion of the cylindrical portion 51 is hermetically sealed from the outer surface of the cylinder head 23. Details of the structure associated with the seal will be described below. On the other hand, at the rear end of the front space M1, the rear end edge of the cylindrical portion 5 is in airtight contact with the front end surface 206 of the crankcase 24. Specifically, the rear end edges of the upper wall 243, the left wall 244, and the bottom wall 245 of the tubular portion 51 abut against the front end surface 206 of the crankcase 24. Further, in the rear space M2, the rounded plate portion 248 of the side plate portion 52 and the right side surface 246 of the curved shaft portion 24 are hermetically sealed. Next, the structure related to the sealing will be explained. Figure 1 is a cross-sectional view of the main portion of the ΧΙΙ-ΧΠ line along Figure 3. Referring to Figs. 3 and 12, an arc-shaped third sealing member 249 is inserted between the left end edge of the arcuate plate portion 248 of the side plate portion 52 and the right side surface 246 of the crankcase 24. The third sealing member 249 is formed in a shape of a shape of 141431.doc -25· 201016492 which is a circular arc shape of the arcuate plate portion 248. Further, the upper surface, the bottom surface, the rear side surface, and the left side surface of the crankcase 24 are not covered by the mask 50 but exposed. The fan 56 is disposed at the end portion of the cover plate 5A in the front-rear direction XI of the vehicle. The fan 56 is disposed in the rear space m2. Further, an intake portion 58 is formed on the side plate portion 52. The intake portion 58 includes a plurality of small openings formed on the right side of the fan 56. After the fan 56 is rotated, the outside air is introduced into the rear space m2 through the intake portion 58. Referring to Figs. 5 and 11', a through hole 59 is formed at an end portion of the mask plate 5A. The through hole 59 is disposed in the front wall 242 of the tubular portion 51 and the front end side of the bottom wall 245. The exhaust pipe 43 is inserted through the through hole 59. Further, a discharge port 250 is formed on the front end side of the bottom wall 245. The discharge port 250 is, for example, opened in a rectangular shape. The through hole 59 and the discharge port 250 are arranged in the left-right direction γι of the vehicle. The cooling air introduced into the rear space M2 of the cooling air passage M3 by the fan 56 flows toward the front space M1. At this time, the cooling wind contacts the surface of the engine body 21, thereby taking heat from the engine body 21. Next, a structure relating to the seal between the front end portion of the tubular portion 51 and the outer surface of the rear end portion 2〇7 of the cylinder head 23 will be described. Figure! The front view of the main part of the 3 Series engine unit 2〇 is shown in part. The fourth sealing member 251 and the fifth sealing member 252 which are formed of an elastic member such as rubber are disposed at the front end portion of the tubular portion 51. In the case of the first sealing member 251 and the fifth sealing member, the entire sealing system of the fourth sealing member 251 is formed into a strip-shaped one-piece molded product, and 141431.doc •26-201016492 is attached to On the cylindrical portion 51. The fourth sealing member 251 includes a first portion (5) and a second portion 2 5 4 . At the front end of the upper wall 243, an crocodile portion 255 protruding downward is formed. The first portion 253 of the fourth sealing member 25 is attached to the 'edge portion' of the crotch portion 255 of the upper wall 243. In the first portion (5), the crocodile portion 255 and the outer surface of the steam red cover 23 are hermetically sealed. Further, at the front end of the left wall 244, a crotch portion 256 that protrudes to the right side is formed. The crotch portion 256 of the left wall 244 is formed corresponding to the shape of the left side surface of the cylinder head 23. Specifically, the crocodile portion 256 is recessed toward the left side in the direction of the vehicle up and down direction 21. The second portion 254 of the fourth sealing member 251 is formed in a groove shape, whereby the second portion 254 is formed in a shape conforming to the shape of the edge portion of the crotch portion 256 of the left wall 244. The second portion 254 of the fourth sealing member 251 is attached to the edge of the flange portion 256 of the left J 244. The second portion 254 hermetically seals the crotch portion 256 and the opposing portions of the left side faces of the cylinder head 23 to each other. The fifth fifth sealing member 252 is formed as a strip-shaped one-piece molded article and held by the tubular crotch portion 51. The fifth sealing member 252 includes a first portion 257, a second portion 258, and a third portion 259. A crotch portion 260 that protrudes upward is formed at a top end ' of the bottom wall 245. The crotch portion 260 is abutted against a portion of the bottom surface of the cylinder head 23 that faces the crotch portion. The first portion 257 of the fifth seal member 252 is attached to the edge P of the bottom wall 245 from the intermediate portion to the right end portion of the vehicle left-right direction Y1. The first portion 257 hermetically seals the flange portion 26 of the bottom wall 245 and the facing portion of the cylinder head with the bottom surface thereof. At the lower end of the front end of the right wall 242, a crotch portion 261 protruding toward the right side 141431.doc -27-201016492 of the cylinder head 23 is formed. The second portion 258 of the fifth sealing member 252 is attached to the edge portion of the crotch portion 261 of the right wall 242. The second portion 258 hermetically seals the opposing portion between the crotch portion % and the right side surface of the cylinder head 23. The third portion 259 of the fifth seal member 252 is in contact with the outer peripheral surface of the fifth sleeve 262 protruding from the cylinder head 23 from the front side. The upper end of the third portion 259 of the fifth seal member 252 is fixed to the cylinder head 23 in the vicinity of the fifth sleeve 262. The fifth sleeve 262 is inserted into the cylinder head 23 by an ignition plug (not shown). Referring to Figs. 5 and 13, a recess 263 through which the fifth sleeve 262 is inserted is formed at the front edge of the right wall 242. The edge of the concave portion 263 is in contact with the outer circumferential surface of the fifth sleeve 262. The outer peripheral surface of the fifth sleeve 202 is surrounded by the edge portion of the concave portion 263 and the third portion 2W of the fifth sealing member. Figure 14 is a partial enlarged view of Figure 9. Referring to Fig. 5 and Fig. 14, a notch portion 6A is formed at the front end of the upper wall 243 of the tubular portion 51. The notch portion 6 is formed such that a portion of the front end of the upper wall 243 is recessed toward the rear side. The edge portion 264 of the notch portion 60 includes a first edge portion 265 that faces the flange 222 of the steam red cover 23, and a second edge portion 266 that faces the downstream end forming portion 241 of the auxiliary air intake passage forming body 41. And the third edge portion 267. The flange 222 of the cylinder head 23 has an opposing portion 268 opposite to the first edge portion 265. The shape of the first edge portion 265 conforms to the shape of the opposing portion 268. Specifically, in the first edge portion 265, the front side portion of the vehicle front and rear direction is substantially parallel to the vehicle front and rear direction XI, and the intermediate portion in the vehicle front and rear direction XI extends obliquely to the right rearward side, and the vehicle The rear side portion in the front-rear direction X1 is substantially parallel to the vehicle left-right direction γ 1 . 141431.doc -28 - 201016492 The central portion of the notched portion 60 in the vehicle left-right direction Y1 serves as a first opening region N1 for exposing the flange 222 of the cylinder head 23. The first edge portion 265 and the opposing portion 268 of the flange 222 of the air cylinder head 23 are hermetically sealed by the sixth sealing member 269. The sixth sealing member 269 is attached to the upper wall 243. The second edge portion 266 is disposed at the right end of the cutout portion 60. Further, the second edge portion 266 is disposed in the vicinity of the other end of the hose 237 of the auxiliary air intake passage forming body 41 and the fourth sleeve 239. The second edge portion 266 has a shape recessed to the right side in a plan view. When β is viewed from the right side, the rear end of the second edge portion 266 has a shape that extends substantially parallel to the front and rear directions XI of the vehicle. Further, in the right side view, the front end of the second edge portion 266 has a shape recessed toward the lower side. The outer peripheral surface of the fourth sleeve 239 has an opposing portion 270 opposed to the second edge portion 266. Further, the outer peripheral surface of the other end of the hose 237 has an opposing portion 272 opposed to the second edge portion 266. The second edge portion 266 is spaced apart from the opposing portion 270 by a few mm or so and the second edge portion 266 and the opposing portion 272 are spaced apart by about several mm. Thus, the first air passage qi is formed between the opposing portions 270 and 272 of the second edge portion 266 and the downstream end forming portion 241. In other words, in the mask panel %, the second edge portion 266 is a portion that forms the first air passage 屮. Further, in the auxiliary air intake passage forming body 41, each of the opposing portions 270 and 272 is a portion in which the first air passage Q1 is formed between the shroud plate 50 and the shim plate 50. The first air passage Q1 communicates with the space outside the cooling air passage river 3 and the shroud plate 50 in the shroud plate 50. A part of the cooling air in the cooling air passage M3 is discharged to the outside of the mask plate 5 through the first air passage Q1. The notch portion 60 is formed in the vicinity of the second edge portion 266, and forms a second opening region N2 for exposing the fourth sleeve 141431.doc • 29· 201016492 239. The third edge portion 267 is disposed at the right end of the front end portion of the cutout portion 60. Further, the third edge portion 267 is disposed in the vicinity of the first sleeve 32. The third edge portion 267 is formed in an arc shape. The third edge portion 267 extends along the opposing portion 271 of the outer peripheral surface of the first sleeve 32 opposite to the third edge portion 267. That is, the opposing portion 271 forms a portion of the downstream end forming portion 241. The third edge portion 267 is spaced apart from the opposing portion 27 1 of the first sleeve 3 2 by a few mm. Thereby, a second air passage Q2 is formed between the third edge portion 267 and the opposing portion 271 of the first sleeve 32. That is, in the mask plate 5, the third edge portion 267 is formed as an edge portion of the second air passage Q2. The second air passage Q2 communicates with the cooling air passage M3 in the mask 50 and the space outside the mask 50. Further, the second air passage Q2 communicates with the first air passage qi. As described above, the i-th air passage ... and the second air passage are formed around the downstream end forming portion 241. One of the cooling winds in the cooling air passage M3 is discharged to the outside of the mask 50 through the second air passage 卩2. The notch portion 60 is formed in the vicinity of the third edge portion 267, and forms a third opening region N3 for exposing the first sleeve 32. That is, in the notch portion 60, the third opening region N3 for preventing the interference between the mask plate 5 and the first sleeve 32 of the ejector is formed on the right side of the first opening region N1. The first sleeve is used. 32 protrudes from the third opening region N3 toward the outside of the mask 50. Further, the fourth sleeve 239 is disposed in a portion of the first sleeve 32 that protrudes outward from the mask 50. Therefore, the auxiliary air intake passage forming body 41 The outer surface of the mask 50 is connected to the cylinder head 23. Referring to Fig. 11 and Fig. 14, the second and third edge portions 266, 267, and arranging the i-th air passage ... and the second air passage Q2 are formed. The outlets 250 and 141431.doc • 30· 201016492 The through holes 59 are vertically disposed via the cylinder head 23 of the engine body 21. Further, the first air passage Q1 and the second air passage Q2, the discharge port 250, and the through hole 59 are in the vehicle. The front-rear direction XI is located at the front end of the tubular portion 51 as a discharge portion. That is, the second air passage Q1 and the second air passage Q2, which are discharge portions for discharging the cooling air in the mask 5, are disposed. 250 and the through hole μ are disposed on the front side of the mask plate 5〇 in the front and rear direction XI of the vehicle. The operation of the form will be described. Referring to Fig. 3 and Fig. 5, when the crankshaft 57 of the engine body 21 is driven, the fan 56 rotates. By this, the outside air is used as the cooling air to the intake air from the mask 50. The portion 58 is introduced into the rear space M2 of the cooling air passage M3 in the mask 50. At this time, the flow of the outside air is indicated by an arrow R1. The cooling air introduced into the rear space M2 is cooled by the fan in the cooling air passage M3. The middle portion is conveyed toward the front side of the vehicle in the front-rear direction to form a cooling air. At this time, the flow of the cooling air is divided into the flow toward the upper wall 243 of the tubular portion 51 of the mask 50 as indicated by an arrow R2, and toward the bottom wall. The flow of 245 is thereby circulated by the cooling air passage M3 from the rear space M2 to the front space M1 to capture the heat of the engine body 21. The cooling wind reaching the lower portion of the front space mi is as shown in Figs. 5 and 11 As shown by the arrows, the discharge port 25〇 and the through hole 59 are discharged. With reference to Fig. 5 and Fig. 14, one part of the cooling air reaching the upper portion of the front space M1 is indicated by the arrow R4, and the first air passage is the first and the second. 2 air passages 〇 2 are arranged to the outside of the mask 50 The cooling air is blown to the outer surface of the downstream end forming portion 241 of the auxiliary air passage forming body 41. Thereby, the cooling air passing through the second air passage Q2 of the first air passage takes heat from the downstream end forming portion 241. The junction 14I431. Doc -31 · 201016492 If the intake air of the downstream end of the auxiliary air intake (4) is maintained at a low temperature, it is guided into the injection space G3. Again, from the ith air passage... and the second air passage Part of the discharged cooling air is blown toward the i-th sleeve 32. Thereby, the cooling air also captures the heat of the first cylinder 32, thereby cooling the cutting (four) mounted on the first #f32. According to this embodiment, the following effects can be obtained. That is, the engine unit (10) is an oxygen-cooled engine unit. Therefore, there is no need for a heat sink or cooling water pump necessary for a water-cooled engine unit. Thus, the unit 20 can be realized with a simple structure.

Further, a forced air cooling type in which a cooling wind is forcibly generated by the fan 56 is employed. Therefore, it is not necessary to arrange the engine unit 2 to the portion where the wind blows on the locomotive 2 。. Therefore, the degree of freedom in the configuration of the engine single core in the locomotive can be improved. Further, when the vehicle is in motion, the fan 56 rotates at high speed together with the crankshaft 57, thereby generating sufficient cooling air in the mask 50. As a result, a sufficient amount of cooling air passes through the i-th air passage ... and the second air passage to the second air intake passage forming body 4, so that the auxiliary air intake passage forming body 4 is cooled by the cooling wind of the fan 56. . Thereby, it is possible to prevent the auxiliary air intake (4) from being heated by the heat of the engine body 21, so that the auxiliary air is ventilated through the auxiliary air intake passage, or the ejector 34 through which the auxiliary line flows does not become high temperature. As a result, the temperature of the mixture of the auxiliary g gas and the fuel is lowered, so that the combustion efficiency of the fuel can be improved. Further, at least during idling, the intake air is guided as auxiliary air from the auxiliary air intake passage K1 to the injection space (7). Thereby, the auxiliary air is blown to the fuel injected from the nozzle of the nozzle 141431.doc •32, 201016492 I5, thereby promoting the atomization of the fuel. As a result, the combustion efficiency of the fuel at the time of idling or low load is improved. Further, the auxiliary air intake passages are formed by the main air intake passages disposed in the tubular body 220 outside the mask plate 50, so that the connection portion of the virtual at least the tubular body is connected. On the outside of the mask 5G. As a result, it is difficult for the entire intake passage K1 of the field to be affected by the heat in the mask plate 5G, so that the auxiliary air passing through the auxiliary air intake passage K1 can be maintained at a low temperature. Therefore, the ejector 34 can be cooled by the auxiliary air at a low temperature, so that the temperature of the fuel passing through the ejector 34 can be lowered, so that the combustion efficiency of the fuel can be further improved. Thus, when the cooling air of the fan 56 is idling less due to the low speed rotation of the crankshaft 57, the combustion efficiency of the fuel can be improved. Moreover, the downstream end forming portion 241 is disposed in the vicinity of the injection nozzle 35 disposed on the cylinder head 23 which is easily heated by the heat from the combustion chamber A1. Therefore, the downstream end forming portion 241 is easily subjected to the heat of the cylinder head 23. However, the downstream end forming portion 241 is surely cooled by the cooling air passing through the first air passage 卩丨 and the second air passage Q2. Therefore, it is possible to surely suppress the heating of the auxiliary air passing through the downstream end K3 of the auxiliary air intake passage K1. Further, a downstream end forming portion 241 is disposed on the outer side of the mask plate 50. Therefore, the hot air of the engine body 21 in the mask 50 is difficult to be transmitted to the downstream end forming portion 241. Therefore, the heat of the engine body 21 is hard to be transmitted to the auxiliary air in the downstream end K3 of the auxiliary air intake passage K1. Thereby, it is possible to surely suppress the auxiliary air from becoming the south temperature. Further, the cooling air can be formed from the second edge portion 266 of the mask 50 and the third edge portion 267 and the first air passage 141431.doc • 33· 201016492 formed between the opposing portions 271, 270 and 272. Q1 and the second air passage Q2 are blown toward the downstream end forming portion 241. The i-th air passage (four) and the second air passage Q2 are located in the vicinity of the downstream end forming portion Μ. Therefore, the cooling air can be surely blown to the downstream end forming portion 241. Thereby, it is possible to more reliably suppress the heating of the auxiliary air passing through the phantom downstream end K3 of the auxiliary air intake passage. Further, in the mask 50, as shown by the arrows, the flow of the cooling air from the fan % toward the first air passage 1 and the second air passage Q2 is generated. The fan 56 faces the discharge port 250 and the through hole. 59 the flow of cooling wind. The cooling air flows in a manner across the cylinder head 23. Therefore, the area where the φ cooling air flows in the mask 50 can be made larger, so that the engine body 21 can be efficiently cooled. Further, it is possible to suppress the flow of the first air passage Q1 and the second air passage Q2, and the cooling air is introduced to the discharge port 250 and the through hole 59 side. Therefore, the cooling air can be reliably discharged from the first air passage ... and the second air passage to effectively cool the downstream end forming portion 241. Further, a connecting pipe 39 is inserted between the tubular body 22A of the throttle body 38 and the cylinder head 23. Thereby, the upstream end forming portion 240 of the throttle valve _ or the auxiliary air intake passage forming body μ can be surely spaced apart from the temperature-closed cylinder head 23 .热 The heat of the eight-cylinder head 23 can be hardly transmitted to the upstream end forming portion 240 of the auxiliary air intake passage forming body 41. As a result, it is possible to more reliably suppress the auxiliary air in the upstream end caliper 2 of the auxiliary air intake passage K1 from being heated by the heat of the cylinder head 23, and to circulate the cylinder 22 from the cylinder head 23 to the throttle body 38. The heat to be transmitted is blocked by the connection pipe 39. That is, the connecting pipe 39 can be utilized as a heat insulating member between the cylinder head 23 and the throttle body 38. Further, the entire auxiliary air passage forming body 41 is disposed outside the cover plate 5 of the lower temperature than the inner side of the mask plate 5, 14J431.doc -34·201016492. Thereby, the auxiliary air in the auxiliary air passage formation body 41 can be maintained at a lower temperature. Further, the mask 50 is disposed so as not to cover the i-th sleeve 32 or the ejector 34. Thereby, the mask panel 5 can be made small, so that the space G1 below the seat 16 can be made more spacious. According to the above, the locomotive '2〇0' of the engine unit 2〇 can be realized. Further, since the engine unit 20 is of a forced cooling type, it is not necessary to blow the wind to the engine body, and the degree of freedom of the engine unit 2 in the locomotive 2 can be improved. As a result, the engine unit 20 can be disposed so as to be surrounded by the vehicle body cover 18. That is, the present invention can be applied to a locomotive of a small turbine type. Further, the promotion of the atomization of the fuel by the auxiliary air at a low temperature and the cooling air of the fan 56 cool the auxiliary air in the auxiliary intake passage forming body, so that even in the case of idling or running, Both locomotives with extremely high fuel combustion efficiency can be realized. Further, the engine body 21 can be disposed in a posture of being tilted down in the longitudinal direction of the vehicle. Thereby, the engine body associated with the vehicle up and down direction 21 can be provided. The size is small. Thereby, the space between the engine body 21 and the seat 16 can be made more spacious. Therefore, for example, the storage a having a large volume can be disposed in the space, and in this case, the height of the seat can be prevented from being excessively high. Further, the cooling air of the fan 56 can be blown from the rear end of the mask 5 to the front end. Thereby, the cooling air of the fan 56 can be blown to a wider area on the surface of the engine body 21, so that the engine body 21 can be efficiently cooled. Further, the engine unit 20 of the present embodiment includes an engine body 21 having a cylinder head 23, a fan 56, and a mask 5 covering an area of the engine body 21 other than a portion of the cylinder cover 23 of at least 141431.doc-35·201016492. And an injector 34 mounted on a portion of the cylinder head 23 that is exposed outside the mask 50. Further, the first air passage Q1 and the second air passage Q2 that communicate the cooling air passage m3 between the mask 50 and the engine body 21 to the outside of the mask 50 are formed in the vicinity of the injector 34. According to this configuration, the mask 5 does not cover the entire body of the engine body 21, and covers the area of the engine body 21 excluding at least a part of the cylinder head 23. Therefore, the enlargement of the mask sheet 5 can be avoided. Further, a portion of the cooling air introduced into the cooling air space M3 between the mask 50 and the engine body 21 by the fan 56 will come from the first! The air passages... and the second air passages flow out to the outside of the mask 50. When the cooling air passes near the injector 34, the injector 34 is cooled, so that the temperature rise of the injector 34 can be suppressed. Further, a portion of the cylinder head 23 exposed to the outside of the mask plate 5 is formed with a first sleeve 32 for attaching the ejector 34 to the third edge portion 267 of the mask plate 5 and the first sleeve 32. The second air passage is formed between the outer peripheral surfaces. Therefore, the cooling air flowing out of the second air passage 卩2 passes through the vicinity of the ejector 34, so that the ejector 34 can be effectively cooled. Moreover, the cylinder head 23 and the ejector 34 are slid in the front and rear directions of the vehicle in the front and rear of the engine body 2, and the fan 56 is disposed on the rear side of the mask plate 50 in the front-rear direction of the vehicle for discharging the mask plate. The cooling air discharge port 250 and the through hole 59 in the inside of the vehicle are placed on the front side of the mask plate % in the front and rear direction of the vehicle. According to this configuration, the fan 56 is introduced into the mask plate 5 from the air 141431.doc • 36- 201016492, the passage Q1, the second air passage Q2, the discharge port 250, and the through hole 59 to the outside of the mask 50. The discharged cooling air flows in the entire front of the vehicle in the mask plate 5〇. The first air passage Qi and the second air passage q2 are disposed at the downstream end portion of the cooling air flow in the shroud plate 50. Thereby, the outflow of the cooling air from the first air passage Q1 and the second air passage Q2 can be promoted.

Further, the first air passage Q1 and the second air passage q2, the discharge port 25A, and the through hole 59 are disposed at positions on the opposite sides of the engine body 2A. Therefore, it is difficult to introduce the cooling air flowing out of the first air passage Q1 and the second air passage 卩2 to the discharge port 250 and the through hole 59 side. Therefore, the cooling air can be surely discharged from the first air passage Q1 and the second air passage Q2. Further, a first opening α region N1 for exposing the flange 222 of the cylinder head 23, which is a connection region between the outer surface of the cylinder head 23 and the downstream end of the intake pipe 36, is formed in the mask plate 50. Thereby, the mask 5Q does not cover the underside of the intake pipe, so that the mask 5 can be miniaturized as compared with the case where the cover plate covers the downstream end of the main intake passage. Further, a portion of the cylinder head 23 exposed to the outside of the mask 50 is formed with a downstream end forming portion 241 of the money passage forming body 41. According to this configuration, the J intake passage forming body 41 is connected to the cylinder head 3 outside the mask plate 5, and thus the lower end forming portion 241 of the auxiliary air intake passage forming body 41 is covered by the mask. The masking plate 50 can be miniaturized. The downstream end forming portion 241 is formed in the vicinity of the first air passage... and the second empty air passage Q2, and thus the air passage (10) and the second air passage are provided. The cooling air that has flowed out can cool the downstream end forming portion 241 of the auxiliary air intake passage forming body 41. Therefore, it is possible to avoid the auxiliary empty space supply from the auxiliary air intake passage 14143J.doc •37· 201016492 to the injection space G3, and the concentration of the gas of the metal 稍 助 助 下降 下降 下降 因 因 因 因 因 浓度 浓度. < Referring to Fig. 5 and Fig. 9, the body pad 53 is formed as a body pad 5 next. The protective pad 53 covers the outside of the right side of the (four) tube 43 (four) Μ. The protective pad 53 is formed in such a manner that the side plate portion protrudes downward from the lower edge of the main plate portion 247. The protective pad 53 is formed in an elongated shape in the front-rear direction of the vehicle, and is disposed on the right side of the exhaust pipe 43. Further, the position where the guard _ is slammed in the front and rear direction of the vehicle is the position corresponding to the fan 56. In other words, the guard_ is disposed at a position near the fan 56. The rear end of the protective pad 53 protrudes rearward toward the rear end of the side plate portion 52. A mask as a cooling mechanism of the engine body is disclosed in Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. However, a protective pad for covering the exhaust pipe or the muffler is not formed on the mask. Therefore, if you want to set a protective pad, it will increase the number of parts. On the other hand, in the present embodiment, since the guard 塾 53 and the mask 50 are integrally formed, the number of parts may be small. Further, the protective pad 53 is disposed in the vicinity of the fan %. Thereby, a portion of the air that is sucked into the fan 56 is brought into contact with the surface of the protective pad 53, so that the temperature rise of the protective pad 53 can be suppressed. Further, since the protective pad 53 is formed in a shape substantially parallel to the longitudinal direction of the exhaust pipe 43, the guard 塾 53 does not become large to be wasted. Thereby, the enlargement of the mask 50 can be avoided. <Embodiment 2> Fig. 15 is a partial sub-surface 141431.doc -38 - 201016492 of a main part of another embodiment of the present invention. In the present embodiment, the same components as those in the above-described embodiments are mainly described, and the same components as those in the above-described embodiments are denoted by the same reference numerals, and their description is omitted. Referring to Fig. 15, in the present embodiment, the lower end forming portion 241 of the auxiliary air intake passage forming member 41 is disposed inside the mask plate 50. Specifically, the mask 50 further includes a cover member 275 that is fixed to the upper wall 243 of the tubular portion 51. The cover member 275 is separately formed separately from the half members 54L, 54R (the half member 54L is not shown). The cover member 275 is located on the upper side of the upper wall 243. The cover member 275 includes a first cover 276 and a second cover 277 disposed on the rear side of the first cover 276. The first cover 276 is disposed in front of the first sleeve 32, and covers the first sleeve 32, the holder 33, the ejector 34, and the downstream end forming portion 241 from the front side. The second cover 277 is formed to have an inverted shape, for example, when viewed in the front-rear direction of the vehicle. The front end of the second cover 277 is connected to the first cover 276. The second cover 277 covers the first sleeve 32, the holder 33, the ejector 34, and the downstream end forming portion 241 from the right side, the upper side, and the left side. On the inner side of the second cover 277, an upper space M4 which is a part of the cooling air passage M3 is formed. The upper space M4 is connected to the front space M丨. Further, a third air passage is formed between the end portion 277a of the second cover 277, the adjacent portion 243a adjacent to the rear end portion 277a of the upper wall 243, and the other end 2373 of the hose 237 of the downstream end forming portion 241. Q3. The third air passage Q3 is formed around the downstream end forming portion 241 and communicates with the space outside the cooling air passage M3 and the mask 5. The third air passage Q3 can discharge the cooling air. The cooling air discharged from the first air passage Q1 and the second air passage Q2 is blown to the downstream end forming portion 241' in the upper space M4 in the cover member 275 as indicated by the arrow 141431.doc -39 - 201016492 arrow R4. As indicated by the arrow ruler 5, it is discharged from the third air passage (7) to the rear of the cover member 275. According to the present embodiment, the downstream end forming portion 24 is disposed inside the cover member 275 of the mask sheet 5 through which the cooling air flows, so that the cooling air of the fan % can be surely blown to the downstream end forming portion 241. Therefore, it is possible to surely suppress the heating of the downstream end forming portion 241 and the auxiliary air inside thereof by the heat of the engine body 21 by the cooling wind. <Other Embodiments> The present invention is not limited to the embodiments described above based on the description and the drawings. For example, the embodiments described below are also included in the technical scope of the present invention. (1) The mask plate covers the entire cylinder head of the engine body. (2) It is not limited to the aspect in which the cooling air is blown to the downstream end forming portion of the auxiliary air intake passage forming body. The cooling air can also be blown to the auxiliary air intake passage. (3) It is possible to prepare a wind guide member which is formed separately from the mask plate, and the cooling air discharged from the mask plate is blown toward the auxiliary air intake passage forming body by the air guiding member. ^ (4) The discharge port can be placed near the second air passage and the second air passage (5). The first air passage and the second air passage can be abolished. (6) At least a part of the auxiliary air intake passage forming body except the upstream end forming portion may be disposed in the mask. (7) The cylinder head and fuel injection device can be placed in the front-rear direction of the vehicle at 141431.doc • 40- 201016492 The middle portion of the engine body can also be disposed at the rear end and coaxial with the crankshaft, and in the vehicle front and rear direction, The t-part can also be arranged at the front end. (8) The bow engine unit can also be fixed to the frame body, and the body can be pivotally supported by the pivot. The (9) auxiliary air intake passage forming body is not limited to a form formed separately from the intake pipe. The auxiliary air intake passage forming body may be formed integrally with the member forming the connecting pipe. gas

(10) The gap between the edge of the front end of the mask and the outer peripheral surface of the ejector can be used as the discharge cooling line. Further, a hole portion having a through-type shape may be formed in the vicinity of the mouthpiece of the material sheet, and the hole portion may be discharged as a gas passage. (11) The air passage through which the cooling air is discharged may be disposed on the upstream end side of the cooling air passage, or may be disposed substantially at the intermediate end and the downstream end.

. Similarly, the fan can be configured to the engine body without the need for a separate component relative to the frame relative to the frame (12). (13) The protective pad can be placed away from the intake fan. (14) The protective pad may cover the entire form of the exhaust pipe, cover one part of the exhaust pipe and a part of the muffler, cover the entire part of the exhaust pipe and a part of the muffler, and cover the exhaust pipe. The whole form of the whole and the silencer, and one of the forms covering one part of the silencer and the whole form. (15) When the auxiliary air intake passage forming body is formed as a sub-intake passage that connects between the first and second throttle valves and the injection space formed in the cylinder head, the same can be implemented as described above. 141431.doc 201016492 The composition of the form is not @. For example, the third sleeve can be omitted, and the other end of the hose can be embedded and fixed to the fourth sleeve. Further, the fourth sleeve may be omitted, and a recess may be formed in the first cylinder, and the third sleeve may be inserted and fixed in the recess. Also, it can also be a provincial poverty. Female μ β starts JJJ horse 3rd sleeve and 4th sleeve and directly fixes the end of the hose to the first sleeve * ^ Also, it can form a depression on the tubular body of the throttle body. And fixing the end of the hose in the recess. (16) The engine unit can be mounted on other vehicles than the locomotive. As such a vehicle, an ATV (A11 Terrain Vehicie, a vehicle suitable for all terrains) or a straddle type vehicle such as a snowmobile can be exemplified. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a right side view of a locomotive according to an embodiment of the present invention; Fig. 2 is a partially enlarged right side view of a locomotive around a body cover; Fig. 3 is a partial sectional view of the engine unit, showing a top view engine unit Figure 4 is a longitudinal sectional view of the main part of the engine unit, showing the state of the engine unit viewed from the right side; Figure 5 is a right side view of the engine unit, showing a part of the engine unit and a part of the imaginary line That is, the two-point chain line is shown; FIG. 6 is a schematic right side view of the throttle body; FIG. 7 is a line diagram showing the relationship between the opening degree of the first throttle valve and the opening degree of the second throttle valve; 1 is a schematic right side view of the throttle body when the throttle valve and the 2nd throttle valve are fully open; FIG. 9 is a plan view of the mask plate; 141431.doc • 42- 201016492 Fig. 1 Left side view of the tethered engine unit; A bottom view of a portion of the mask; Figure 12 is a cross-sectional view of the main part of the ΧΙΙ-ΧΙΙ line of Figure 3; a front view of the main part of the engine unit; Figure 14 Figure 9 An enlarged portion of FIG.; FIG. 15 and based further embodiment of the present invention of FIG. Part of the profile

[Main component symbol description] 15 Frame body 16 Seat 17 Foot pedal 18 Body cover 20 Engine unit (force air-cooled engine unit for vehicle) 21 Engine body 22 Cylinder block 23 Cylinder head 24 Crankcase 32 1st sleeve (Sleeve for accommodating nozzle) 34 Injector (fuel injection device) 35 Injection nozzle 36 Intake pipe 38 Throttle body 39 Connection pipe 141431.doc -43- 201016492 40A, 40B Throttle valve 41 Sub intake passage forming body 50 Mask plate 56 Fan 57 Crankshaft 59 Through hole (discharge portion) 200 Locomotive 207 Steam red cover rear end (cylinder 208 Piston 220 cylindrical body 240 upstream end forming portion 241 downstream end forming portion 250 discharge port (discharge portion) 264 edge Part (the air passage 270' 272 opposite portion (the downstream end forming portion 271 opposite portion (the downstream end forming portion A1, the combustion chamber C1, the flow direction of the intake air G1, the space G3, the injection space (the injection nozzle is attached with the K1 sub intake air) The upstream end K3 of the auxiliary air intake passage of the passage K2, the downstream end M3 of the auxiliary air intake passage, the cooling air passage (the inner surface of the mask), and the surface) 141431.doc -44 _ 201016492

PI Qi Q2 Q3 XI Main air intake passage First air passage (discharge unit) Second air passage (discharge unit) Third air passage Vehicle front and rear direction ❹ 141431.doc •45-

Claims (1)

201016492 VII. Patent Application Range: 1. A forced air-cooled engine unit for a vehicle, comprising: an engine body that includes a crankcase that houses a crankshaft, and a cylinder block that can be reciprocally received by a piston connected to the crankcase, And a cylinder head that forms a combustion chamber together with the cylinder block and forms a portion of a main intake passage connected to the combustion chamber; an intake pipe connected to the cylinder head, and the main intake air is formed together with the cylinder head path; a mask plate covering at least one portion of the cylinder head; a fan disposed between the mask plate and the engine body, driven by rotation of the crankshaft to generate cooling air for cooling the engine body; a throttle body having two throttle valves that are disposed at intervals in a flow direction of the intake air in the intake pipe, and a tubular body that forms one of the intake pipes and houses the two throttle valves, and Provided outside the above-mentioned mask plate; a fuel injection device mounted on the cylinder head, having an injection nozzle that injects fuel into the main intake passage of the cylinder head; and a sub intake passage forming body that forms a sub intake a passage, the auxiliary air intake passage is branched from the main intake passage between the two throttle valves, and the intake guide is bowed to a space formed on the steam red cover at least in the vicinity of the spray nozzle at least during idling And at least two of the knives around the auxiliary air intake passage have an air passage that communicates a space in the material plate with a space of the mask. 141431.doc 201016492 2. The forced air-cooled engine unit for a vehicle according to claim 2, wherein the auxiliary air intake passage includes an upstream end connected to the main intake passage and a downstream of the space connected to the vicinity of the injection nozzle The auxiliary air intake passage forming body includes an upstream end formed to form the upstream end. And a downstream end forming portion forming the downstream end, wherein the cold portion wind is guided at least to the downstream end forming portion. 3. The forced air-cooled engine unit for a vehicle according to claim 2, wherein the nozzle 2: the rainbow cover includes the downstream (four) portion of the auxiliary air intake passage forming body that is exposed outside the mask plate and accommodates the injection portion Above #商. 4. The forced air-cooled engine unit for a vehicle according to claim 3, wherein the V-mask includes an edge portion, and the air passage is formed between the edge portion and an outer surface of the downstream end forming portion. 5. The forced air-cooled engine unit of the vehicle of claim 4, wherein the ice sheet W is formed on the mask plate to form a discharge port for discharging the cooling air to the outside of the mask plate. The discharge port is disposed via the cylinder head. . The vehicle of the claim 1 is a forced air-cooled engine unit, in which the tube. The inlet pipe includes a connection between the cylindrical body and the cylinder head. 7. The vehicle-use forced air-cooled engine unit according to claim 1, wherein the outer domain auxiliary air intake passage forming system is disposed on the 141431 of the mask plate. The invention relates to a forced air-cooled engine unit for a vehicle according to claim 2, wherein the downstream end forming portion is disposed inside the mask plate. 9. A locomotive comprising: a frame body extending in a front-rear direction; a seat supported by the frame body; a foot pedal disposed in front of the seat; upward from a rear portion of the foot pedal And a vehicle body cover that surrounds the space below the seat; and the forced air-cooled engine unit for a vehicle according to any one of the items 1 to 8 of the present invention is supported by the frame in a state of being swingable in the up and down direction The body ' is disposed under the above-mentioned seat in such a manner as to be covered by the above-mentioned body cover. The locomotive of claim 9, wherein the cylinder head and the fuel injection device are located at a front end of the engine body in a front-rear direction of the vehicle, and the fan is disposed at a rear end side of the mask in a front-rear direction of the vehicle. The discharge portion for discharging the cooling air in the mask is disposed on the front end side of the mask in the front-rear direction of the vehicle. 141431.doc