Patent Application
20200040780
The present invention relates to an internal combustion engine that includes a crankshaft that is rotatably supported on a crankcase, and a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle.
Patent Document 1 discloses a pulse sensor. The pulse sensor is made to face an outer rotor of a generator. The outer rotor is fixed to an extremity of a crankshaft. A to-be-detected body is mounted on an outer face of the outer rotor. The pulse sensor detects the to-be-detected body in response to rotation of the outer rotor and generates a pulse signal while synchronizing it with the rotation in response to the to-be-detected body being detected.
Patent Document 2 discloses a ring gear (to-be-detected body) that is mounted on a crankshaft of an internal combustion engine when determining misfiring. An extremity of an eddy current type microdisplacement sensor (detection sensor) opposes an outer peripheral face of the ring gear. The microdisplacement sensor detects the crank angle. The positional relationship between a crank chamber of the internal combustion engine and the microdisplacement sensor is not disclosed.
Patent Document 1: Japanese Utility Model Registration Publication No. 2510184
Patent Document 2: Japanese Patent Application Laid-open No. 2014-199040
It is desired that when determining misfiring the angular velocity of a crankshaft is detected with high precision. However, when the outer rotor of the generator plays the role of a ring gear, since the generator is disposed at a shaft end of the crankshaft, the run-out of the crankshaft increases, and it is difficult to detect the angular velocity of the crankshaft with high precision.
The present invention has been accomplished in light of the above circumstances, and it is an object thereof to provide, in a so-called V-type internal combustion engine, a structure for disposing a detection sensor that can detect the angular velocity of a crankshaft with high precision.
According to a first aspect of the present invention, there is provided an internal combustion engine comprising a crankcase that defines a crank chamber, a crankshaft that is rotatably supported on the crankcase, a cylinder block that is joined to the crankcase and defines a plurality of cylinders in a V-type arrangement in which the cylinders are disposed above a virtual horizontal plane including a rotational axis of the crankshaft and intersect each other at a bank angle, a to-be-detected body that rotates integrally with the crankshaft, and a detection sensor that is mounted from an outside at a position, lower than the virtual horizontal plane, of a front face of the crankcase that receives air flow, is made to face a trajectory of the to-be-detected body, and generates a pulse signal in response to movement of the to-be-detected body.
According to a second aspect of the present invention, in addition to the first aspect, the internal combustion engine further comprises an oil cooler that is mounted on an outer face of the crankcase beneath the detection sensor.
According to a third aspect of the present invention, in addition to the first or second aspect, the internal combustion engine further comprises an exhaust pipe that is positioned further forward than the front face of the crankcase and at least partially overlaps the detection sensor when viewed from the front.
According to a fourth aspect of the present invention, in addition to any one of the first to third aspects, the detection sensor is disposed in one space resulting from partitioning by a virtual plane that is orthogonal to the rotational axis of the crankshaft at a middle position in an axial direction of the crankshaft, and a starter motor is disposed in another space resulting from the partitioning.
According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, the internal combustion engine further comprises an oil filter mounted on the outer face of the crankcase at a position beneath the detection sensor.
According to a sixth aspect of the present invention, in addition to any one of the first to fifth aspects, the detection sensor is disposed in one space resulting from partitioning by a virtual plane that is orthogonal to the rotational axis of the crankshaft at the middle position in the axial direction of the crankshaft, and an AC generator is disposed in another space.
According to a seventh aspect of the present invention, in addition to any one of the first to sixth aspects, the detection sensor comprises a main body that is inserted into a through hole formed in the crankcase and faces the crank chamber via a detection part at an extremity, a connector that is joined to the main body and is disposed in a space outside the crankcase, and a fastening piece that is joined to the main body and is fastened to an outer face of the crankcase.
In accordance with the first aspect, due to the detection sensor being mounted on the crankcase, the to-be-detected body can be separated from the outer rotor of a generator, and it is therefore possible to avoid the influence of an electromagnetic force acting between the outer rotor and an inner stator. The angular velocity of the crankshaft can be detected with high precision. Moreover, the detection sensor can be protected beneath the cylinder block. The detection sensor receives air flow and can thus be cooled. In addition, since the detection sensor is mounted from the outside of the crankcase, any increase in the dimensions of the crankcase or a case cover can be avoided.
In accordance with the second aspect, the oil cooler can protect the detection sensor from stones, etc. scattered up from the road.
In accordance with the third aspect, the exhaust pipe can protect the detection sensor from stones, etc. coming from the front.
In accordance with the fourth aspect, since the detection sensor is distant from the starter motor, the influence of the magnetic force of the starter motor can be avoided.
In accordance with the fifth aspect, the oil filter can protect the detection sensor from stones, etc. scattered up from the road.
In accordance with the sixth aspect, since the detection sensor is distant from the AC generator, the influence of the magnetic force of the AC generator can be avoided.
In accordance with the seventh aspect, the detection sensor is merely inserted into the through hole of the crankcase, the detection sensor can easily be fitted into the internal combustion engine, and since it is fastened to the outer face of the crankcase by means of the fastening piece, the sensor can be reliably fixed to the case outer face.
One embodiment of the present invention is explained below by reference to the attached drawings. Here, the top and bottom, front and rear, and left and right of a vehicle body are defined based on the point of view of a person riding a two-wheeled motor vehicle.
An internal combustion engine 23 is mounted on the vehicle body frame 12 between the front wheel WF and the rear wheel WR. The internal combustion engine 23 is arranged as a V-type four cylinder internal combustion engine. The internal combustion engine 23 generates power around a rotational axis Xc. The power of the internal combustion engine 23 is transmitted to the rear wheel WR via a power transmission device (not illustrated).
An exhaust pipe 24 is connected to the internal combustion engine 23. An exhaust muffler 25 is connected to the exhaust pipe 24. The exhaust muffler 25 extends from below the internal combustion engine 23 and has an exhaust port disposed to one side of the axle 21. Exhaust of the internal combustion engine 23 is discharged from the exhaust muffler 25.
A fuel tank 26 is mounted on the vehicle body frame 12 above the internal combustion engine 23. A rider's seat 27 is mounted on the vehicle body frame 12 to the rear of the fuel tank 26. Fuel is supplied from the fuel tank 26 to a fuel injection device of the internal combustion engine 23. When driving the two-wheeled motor vehicle 11 a rider straddles the rider's seat 27.
As shown in
The cylinder rows 33a and 33b are formed as a V-type arrangement in which they are disposed above a virtual horizontal plane HP containing the rotational axis Xc of the crankshaft 32 and intersect each other at a bank angle. The cylinders of the first cylinder row 33a on the front side have a cylinder axis Xf that is inclined forward at an angle that is half the bank angle with respect to a virtual vertical plane containing the rotational axis Xc. The cylinders of the second cylinder row 33b on the rear side have a cylinder axis Xr that is inclined rearward at an angle that is half the bank angle with respect to a virtual vertical plane containing the rotational axis Xc.
The internal combustion engine 23 includes a pulser sensor (detection sensor) 36 mounted from the outside on the crankcase 31 at a position beneath the virtual horizontal plane HP. The pulser sensor 36 projects from an outer face of the crankcase 31 so as to go away from the rotational axis Xc of the crankshaft 32. The exhaust pipe 24 is disposed on the side, in the vehicle width direction, of the pulser sensor 36 while curving. The exhaust pipe 24 overlaps the pulser sensor 36 when viewed from the side of the vehicle. That is, in a projection of the exhaust pipe 24 and the pulser sensor 36 from a direction orthogonal to a virtual plane 43 that is orthogonal to the rotational axis Xc of the crankshaft 32, the projection image of the exhaust pipe 24 and the projection image of the pulser sensor 36 overlap each other.
An oil cooler 37 is mounted on the front face 31a of the crankcase 31 beneath the pulser sensor 36. The oil cooler 37 includes an infeed path joined to an oil passage opening on the front face 31a of the crankcase 31 and an outlet path joined to the cylinder head 34 by means of a pipe member 38. Oil that is cooled by the oil cooler 37 is supplied to the cylinder head 34.
An oil filter 39 is mounted on a side face of the crankcase 31 beneath the pulser sensor 36. The oil filter 39 is connected to two oil passages opening on the side face of the crankcase 31. Oil that is discharged from an oil pump is filtered by the oil filter 39 and returned to an oil passage within the crankcase 31.
As shown in
The internal combustion engine 23 includes an AC generator (ACG) 45. The AC generator 45 includes an outer rotor 46 fixed to the crankshaft 32 extending through the crankcase 31 and projecting from the crankcase 31, and an inner stator 47 disposed around the crankshaft 32 while being surrounded by the outer rotor 46. A generator cover 48 is joined to the crankcase 31. The generator cover 48 covers the AC generator 45 from the outside.
An electromagnetic coil 49 is wound around the inner stator 47. A magnet 51 is fixed to the outer rotor 46. When the outer rotor 46 rotates relative to the inner stator 47, power is generated in the electromagnetic coil 49.
The exhaust pipe 24 is positioned in front of the front face 31a of the crankcase 31, and at least partially overlaps the pulser sensor 36 when viewed from the front. That is, in a projection of the exhaust pipe 24 and the pulser sensor 36 from a direction orthogonal to a vertical virtual plane containing the rotational axis Xc of the crankshaft 32, the projection image of the exhaust pipe 24 and the projection image of the pulser sensor 36 overlap each other. The exhaust pipe 24 curves while bypassing the oil cooler 37 when viewed from the front. That is, in a projection of the exhaust pipe 24 and the oil cooler 37 from a direction orthogonal to the vertical virtual plane containing the rotational axis Xc of the crankshaft 32, the projection image of the exhaust pipe 24 and the projection image of the oil cooler 37 do not overlap each other.
As shown in
The crank 55 includes two crank pins 57 linked to connecting rods 56a and 56b. The crank pin 57 is disposed so as to be parallel to the rotational axis Xc and be displaced from the rotational axis Xc. Linked to the respective crank pin 57 are one piston of the first cylinder row 33a on the front side and one piston of the second cylinder row 33b on the rear side. Here, cylinders of the second cylinder row 33b are disposed so as to be as close to each other as possible, and cylinders of the first cylinder row 33a are disposed with a gap therebetween. Therefore, the connecting rods 56b of the second cylinder row 33b are linked to the crank pins 57 on the side where the bearing 54 in the middle is, and the connecting rods 56a of the first cylinder row 33a are linked to the crank pins 57 on the side where the bearings 54 on the outside in the axial direction are. Linear movement in the axial direction of the piston is converted into rotation of the crankshaft 32 of by virtue of the action of the connecting rods 56a and 56b. The virtual plane 43, which is orthogonal to the rotational axis Xc of the crankshaft 32 at the middle position in the axial direction of the crankshaft 32, forms a lateral plane of symmetry for the cylinders.
The crankshaft 32 includes a first drive shaft 58a projecting from the crankcase 31 via one end in the axial direction, and a second drive shaft 58b projecting from the crankcase 31 via the other end in the axial direction. As described above, the outer rotor 46 of the AC generator 45 is fixed to the first drive shaft 58a. Fixed to the second drive shaft 58b is a sprocket for a cam chain (not illustrated) or a drive gear (not illustrated) meshing with an input gear of a transmission.
Referring in addition to
The pulser ring 61 includes a plurality of reluctors (gear teeth) 61a arranged at equal intervals in an annular shape around the rotational axis Xc. The reluctors 61a are disposed with a central angle of for example 10 degrees therebetween. The reluctor 61a is formed from for example a magnetic body. The pulser sensor 36 is made to face the annular trajectory of the pulser ring 61 and generates a pulse signal in response to movement of the pulser ring 61.
As shown in
The fastening piece 66 is superimposed on an upper face of a pedestal 67 projecting from the front face 31a of the crankcase 31 and fastened to the pedestal 67 by means of a bolt 68. In the pulser sensor 36 a detection axis 69 that has the highest sensitivity is directed at the rotational axis Xc of the crankshaft 32.
The operation of this embodiment is now explained. In the present embodiment the pulser sensor 36 is mounted from the outside at a position, beneath the virtual horizontal plane HP containing the rotational axis Xc, on the front face 31a of the crankcase 31. Due to the pulser sensor 36 being mounted on the crankcase 31 the pulser ring 61 is separated from the outer rotor 46 of the AC generator 45. In this way the influence of an electromagnetic force acting between the outer rotor 46 and the inner stator 47 is avoided. The angular velocity of the crankshaft 32 is detected with high precision. Moreover, the pulser sensor 36 is protected beneath the forwardly inclined cylinder block 33. The pulser sensor 36 receives air flow and is thus cooled. In addition, since the pulser sensor 36 is mounted from the outside of the crankcase 31, any increase in the dimensions of the crankcase 31 can be avoided. On the other hand, if the pulser sensor 36 were to be disposed on the inside of the crankcase 31 or a case cover, it would not be possible to avoid an increase in the dimensions of the crankcase 31 or the case cover. An increase in the dimensions of the crankcase 31 or the case cover would cause a local increase in the weight of the internal combustion engine 23, thus degrading the weight balance of the internal combustion engine 23.
The internal combustion engine 23 related to the present embodiment includes the oil cooler 37 mounted on the outer face of the crankcase 31 beneath the pulser sensor 36. The oil cooler 37 protects the pulser sensor 36 from stones, etc. scattered up from the ground GD. In addition, the internal combustion engine 23 includes the oil filter 39 mounted on the outer face of the crankcase 31 at a position lower than the pulser sensor 36. The oil filter 39 protects the pulser sensor 36 from stones, etc. scattered up from the ground GD. Moreover, the internal combustion engine 23 includes the exhaust pipe 24, which is positioned further forward than the front face 31a of the crankcase 31 and at least partially overlaps the pulser sensor 36 when viewed from the front. The exhaust pipe 24 protects the pulser sensor 36 from stones, etc. coming from the front.
In the present embodiment, as described above, when the virtual plane 43, which is orthogonal to the rotational axis Xc of the crankshaft 32 at the middle position in the axial direction of the crankshaft 32, is set, the pulser sensor 36 is disposed in one space 44a resulting from partitioning by the virtual plane 43, and the starter motor 41 and the AC generator 45 are disposed in the other space 44b. Since the pulser sensor 36 is thus distant from the starter motor 41 and the AC generator 45, the influence of the magnetic force of the starter motor 41 or the AC generator 45 is avoided.
The pulser sensor 36 is inserted into the through hole 63 foil ied in the crankcase 31 and faces the crank chamber 52 via the detection part at the extremity. Since the pulser sensor 36 is merely inserted into the through hole 63 of the crankcase 31, the pulser sensor 36 can easily be fitted into the internal combustion engine 23.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-063118 | Mar 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/004395 | 2/8/2018 | WO | 00 |
