1. Field of the Invention
The present invention relates to a personal watercraft (PWC) which is configured to generate a propulsive force as a reaction of a water jet. More particularly, the present invention relates to a personal watercraft configured to change a direction of a water jet to switch between forward driving and reverse driving.
2. Description of the Related Art
A personal watercraft includes a water jet pump configured to be driven by an engine to generate a rearward water jet and a movable reverse bucket provided at the periphery of the water jet pump. When the reverse bucket is in a forward driving position in which the reverse bucket permits the rearward water jet being ejected from the water jet pump, the personal watercraft can drive forward. On the other hand, when the reverse bucket is in a reverse driving position in which the reverse bucket changes the direction of the water jet being ejected from the water jet pump from a rearward direction to a forward direction, the personal watercraft can drive reversely. The personal watercraft includes a reverse driving operation member operated by the rider. The reverse bucket is configured to move from the forward driving position to the reverse driving position in response to the rider's operation of the reverse driving operation member.
The personal watercraft includes a driving power operation member which is operated by the rider to control an engine driving power. When the driving power operation member is operated by the rider to increase the engine driving power, the water jet is accelerated, causing the watercraft to be accelerated. When the driving power operation member is not operated, the water jet slows, and a body tilts forward. Thereby, a body resistance increases, and the watercraft is decelerated naturally.
According to the present invention, a personal watercraft comprises an engine mounted in a body; a water jet pump configured to be driven by the engine to generate a rearward water jet to apply a propulsive force to the body; a reverse bucket mounted at a periphery of the water jet pump and movable between a forward driving position and a reverse driving position, the reverse bucket being configured to permit the rearward water jet in the forward driving position and to direct the water jet in a forward direction in the reverse driving position; a driving power operation member configured to be operated by a rider to control a driving power of the engine; a reverse driving operation member configured to be operated by the rider to change a position of the reverse bucket from the forward driving position to the reverse driving position; and a deceleration operation member configured to be operated by the rider; wherein the reverse bucket is in the forward driving position when the deceleration operation member and the reverse driving operation member are not operated; and wherein the reverse bucket is in a deceleration position between the forward driving position and the reverse driving position when the deceleration operation member has been operated and the reverse driving operation member is not operated.
In accordance with such a configuration, the propulsive force applied to the watercraft is flexibly adjustable by operating the driving power operation member, and a decelerative effect of water resistance is produced when the driving power operation member is not operated during driving of the watercraft. In addition, when the deceleration operation member is operated by the rider, the reverse bucket moves to the deceleration position between the forward driving position and the reverse driving position, thereby changing the direction of the water jet being ejected from the water jet pump. As the resulting reaction, an additional decelerative effect is produced. Since the rider can select a normal decelerative effect or an enhanced decelerative effect according to the rider's preference, maneuverability of the watercraft is improved.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with reference to the accompanying drawings.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As used herein, the term “directions” refers to directions from the perspective of a rider straddling a personal watercraft.
[Embodiment 1]
Upon the engine 6 starting running, the rotation of the crankshaft 7 is transmitted to the pump shaft 11, causing the water jet pump 10 to operate. The impeller 12 rotates according to a driving power of the engine 6, to pressurize and accelerate the water sucked through the water intake 16, thereby generating a water jet directed rearward. The water jet is guided by the fairing vanes 13 and is ejected rearward from the outlet port 18 through the steering nozzle 19. As the resulting reaction, the watercraft 1 gains a propulsive force for driving the body 2.
A handle 20 is provided in front of the seat 5 and includes a pair of right and left grips which are gripped by the rider. The handle 20 is coupled to the steering nozzle 19 via a steering cable 21 (see
A bowl-shaped reverse bucket 22 is mounted at the periphery of the water jet pump 10. Hereinafter, the surface of the reverse bucket 22, forming a space 22a, is referred to as an inner surface 23, and an opposite surface of the inner surface 23 is referred to as an outer surface 24. The inner surface 23 of the reverse bucket 22 is curved and faces the steering nozzle 19. The reverse bucket 22 is pivotable with respect to the body 2 around a pivot shaft 25 extending horizontally in a rightward and leftward direction. To be more specific, the reverse bucket 22 is pivotable between a forward driving position (indicated by a solid line) in which the reverse bucket 22 is retracted and in an up position and a reverse driving position (indicated by a two-dotted line) in which the reverse bucket 22 extends in a downward direction and is in a down position. The reverse bucket 22 is pivoted clockwise in
A driving power operation member 30 is attached to the right grip 29 of the handle 20. In this embodiment, the driving power operation member 30 is a throttle lever and is pivotally attached to the right grip 29 in front of and adjacent to the right grip 29. The driving power operation member 30 is movable between a first position and a second position. In a state where the driving power operation member 30 is not operated, the driving power operation member 30 is in the first position where the driving power operation member 30 is most distant from the right grip 29. When the driving power operation member 30 is pulled toward the rider, it is moved to the second position where the driving power operation member 30 is closest to the right grip 29.
In this embodiment, the driving power operation member 30 is mechanically coupled to the throttle device 27 via the throttle cable 31. The throttle device 27 is operable to change an air-intake amount according to the position of the driving power operation member 30. This makes it possible to change the speed of the water jet being ejected from the water jet pump 10 driven by the engine 6, and thereby change a propulsive force applied to the body 2 of the watercraft 1.
When the driving power operation member 30 is moved to the second position, the driving power of the engine 6 and hence the propulsive force increase. Under this condition, the watercraft 1 planes on the water surface while the body 2 is slightly tilted in a rearward direction, i.e., the fore portion of the body 2 is moving up. When the driving power operation member 30 is returned to the first position during driving of the watercraft 1, the driving power of the engine 6 decreases and the propulsive force is lost. Under this condition, the body 2 tilts forward and the body resistance increases. By utilizing a decelerative effect of the water resistance, the watercraft 1 is decelerated.
The left grip 32 of the handle 20 is attached with a reverse driving operation member 33 and a deceleration operation member 34. In this embodiment, the reverse driving operation member 33 and the deceleration operation member 34 are lever-type operation members (deceleration operation lever and reverse driving operation lever). The reverse driving operation member 33 and the deceleration operation member 34 are pivotally attached to the left grip 32. The reverse driving operation member 33 and the deceleration operation member 34 are coupled to the reverse bucket 22 via a coupling mechanism 35. The position of the reverse bucket 22 is changed according to the position of the reverse driving operation member 33 and the position of the deceleration operation member 34. In the watercraft 1, the reverse bucket 22 moves in association with the operation of the deceleration operation member 34, to change the direction of the water jet being ejected from the water jet pump 10. As the resulting reaction of the water jet, the watercraft 1 can gain an additional decelerative effect.
The coupling mechanism 35 may include wires configured to mechanically couple the reverse driving operation member and the deceleration operation member to the reverse bucket, as described hereinafter. The reverse driving operation member 33 is coupled to one end portion of a reverse driving cable 36. The deceleration operation member 34 is coupled to one end portion of a deceleration cable 37. The opposite end portions of the cables 36 and 37 are coupled to a coupling member 38. The coupling member 38 is coupled to the reverse bucket 22 via a bucket cable 39. Upon the reverse driving cable 36 and the deceleration cable 37 being pulled forward, the coupling member 38 pushes out the bucket cable 39 in a rearward direction. The coupling member 38 is formed by, for example, a seesaw-like lever which is pivotable around the pivot at its center portion. The reverse driving cable 36 and the deceleration cable 37 are coupled to the one end portion of the coupling member 38, and the bucket cable 39 is coupled to the opposite end portion of the coupling member 38. The deceleration cable 37 is coupled to the coupling member 38 in a location that is more distant from the pivot of the coupling member 38 than the location at which the reverse driving cable 36 is coupled to the coupling member 38. The reverse driving cable 36, the deceleration cable 37 and the bucket cable 39 are push-pull cables. A biasing member 40 is provided between the reverse bucket 22 and the body 2. The biasing member 40 applies a force to place the reverse bucket 22 in the forward driving position. The biasing member 40 includes, for example, a coil spring, etc. Alternatively, another biasing member may be provided between the coupling member 38 and the body 2 to apply a force to allow the reverse driving cable 36 and the deceleration cable 37 to be pulled in a rearward direction and the bucket cable 39 to be pulled in a forward direction.
The deceleration operation member 34 is pivotable between a first position (see
As shown in
When the reverse bucket 22 is in the reverse driving position, the space 22a of the reverse bucket 22 is positioned behind the steering nozzle 19 to surround the rear portion of the steering nozzle 19. To be more specific, the rear portion of the steering nozzle 19 is covered with the space 22a of the reverse bucket 22, and the rear end opening of the steering nozzle 19 overlaps with a part of the reverse bucket 22 as viewed from the rear. The inner surface 23 of the reverse bucket 22 extends downward farther than the lower end portion of the rear end opening of the steering nozzle 19. Under this condition, the water jet being ejected rearward through the steering nozzle 19 collides against the inner surface 23 of the reverse bucket 22, and thereby is directed forward. The water jet is easily guided in a forward direction by the portion of the inner surface 23 of the reverse bucket 22 which extends downward father than the lower end portion of the steering nozzle 19. As the resulting reaction of the forward water jet, the watercraft 1 gains a rearward propulsive force and drives in a reverse direction.
When the reverse bucket 22 is in the deceleration position, the rear portion of the steering nozzle 19 is covered with the space 22a of the reverse bucket 22. To be more specific, the lower end portion of the rear end opening of steering nozzle 19 substantially conforms in vertical position to the rear lower end portion of the reverse bucket 22 in the deceleration position. In this case, the water jet J being ejected from the water jet pump 10 collides against the inner surface 23 of the reverse bucket 22, and changes its direction. The resulting water jet J contains a forward component smaller than the forward component of the water jet in the state where the reverse bucket 22 is in the reverse driving position.
In a case where the rider wishes to produce an decelerative effect in addition to the decelerative effect of the water resistance during forward driving of the watercraft 1, the rider operates the deceleration operation member 34 to generate a reaction of the water jet containing a forward component, thereby applying a propulsive force containing a rearward component to the watercraft 1. In addition, the reaction of the water jet containing a downward component might assist the forward tilting of the watercraft 1, thereby increasing the body resistance. Based on such rearward propulsive force and the forward tilting assist, the watercraft 1 being driving in a forward direction would be able to gain an additional decelerative effect.
As should be readily appreciated from the above, the rider can determine whether or not to produce an additional decelerative effect by determining whether or not to operate the deceleration operation member 34. Therefore, when the rider wishes to decelerate the watercraft 1 during forward driving, the rider can select using a decelerative effect of only the body resistance, or using an additional decelerative effect to enhance a deceleration capability of the watercraft. As a result, maneuverability of the watercraft 1 is improved.
As shown in
The magnitude of the decelerative effect produced using the reverse bucket 22 depends on the speed of the water jet being ejected from the water jet pump 10. When the rider intentionally operates the deceleration operation member 34, the driving power operation member 30 with which an acceleration request or a high-speed driving request is input should be unoperated. In this case, it is difficult to generate a high-speed water jet for the deceleration. Hereinafter, a configuration for improving the decelerative effect produced using the reverse bucket 22 will be described.
The idling control body 51 forms a bypass passage 55 for allowing air flowing into the air-intake passage 52 to bypass the throttle valve 54 and flow out from the air-intake passage 52. A bypass valve 56 is provided in the bypass passage 55 to increase or decrease a passage cross-sectional area of the bypass passage 55. The idling control body 51 is provided with a bypass valve drive device 57 configured to drive the bypass valve 56. The bypass valve drive device 57 includes a stator 58 forming an outer tube. An armature coil 59 is mounted to the inner peripheral surface of the stator 58. A cylindrical rotor 60 is mounted to the inner peripheral side of the armature coil 59 such that the rotor 60 is rotatably supported by the stator 58. A permanent magnet 61 is mounted to the outer peripheral surface of the rotor 60 to be opposite to the armature coil 59. A drive shaft 62 is inserted into the rotor 60. The drive shaft 62 is threadedly engaged with the rotor 60 and is unable to rotate. The bypass valve 56 is spline-coupled to the tip end portion of the drive shaft 62. When a desired current flows through the armature coil 59, the rotor 60 rotates by an electromagnetic induction action and the drive shaft 62 moves axially along with the rotor 60. In this manner, the bypass valve 56 operates to open and close the bypass passage 55.
Further, the engine controller 70 is communicatively coupled to a reverse driving operation sensor 75 configured to detect that the reverse driving operation member 33 is in the second position, and a deceleration operation sensor 76 configured to detect that the deceleration operation member 34 is in the second position. In this embodiment, the reverse driving operation member 33 and the deceleration operation member 34 are mechanically coupled to the reverse bucket 22 via the coupling mechanism 35 so that the position of the reverse bucket 22 is changed according to the position of the reverse driving operation member 33 and the position of the deceleration operation member 34. When the deceleration operation member 34 has reached the second position, the reverse bucket 22 has reached the deceleration position. Therefore, in this embodiment, the deceleration operation sensor 76 serves as a detector configured to detect whether or not the reverse bucket 22 has reached the deceleration position. Likewise, when the reverse driving operation member 33 has reached the second position, the reverse bucket 22 has reached the reverse driving position. Therefore, in this embodiment the reverse driving operation sensor 75 serves to detect whether or not the reverse bucket 22 has reached the reverse driving position.
Referring to
If it is determined that the reverse bucket 22 is in the deceleration position (S1: YES), the driving power of the engine 6 and the engine speed N are controlled according to the deceleration mode (step S6), and then the process returns to step S1. In this embodiment, the position of the reverse bucket 22 is determined with reference to a signal output from the deceleration operation sensor 76 in step S1, and the position of the reverse bucket 22 is determined with reference to a signal output from the reverse driving operation sensor 75 in step S3.
Referring to
If it is determined that the engine speed N is not lower than the first deceleration engine speed NR1 (S62: NO), the flag value f is set to 1 (step S64). The bypass valve drive device 57 is controlled so that the opening degree of the bypass valve 56 is adjusted to obtain an air-intake amount required to maintain the engine speed N at the first deceleration engine speed NR1 (step S65), and then the process returns to the main flow shown
If it is determined that the flag value f is not 0 (S61: NO), it is determined whether or not the flag value f is 1 (step S66). If it is determined that the flag value f is 1 (S66: YES), it is determined whether or not a timer value T is smaller than a predetermined time period T1 (step S67). If it is determined that the timer value T is smaller than the predetermined time period T1 (S67: YES), the time value T is set to a value which is a sum of a current set value and a predetermined value ΔT1 (step S68). The process moves to step S65 and the opening degree of the bypass valve 56 is adjusted to obtain an air-intake amount required to maintain the engine speed N at the first deceleration engine speed NR1. Then, the process returns to the main flow shown in
If it is determined that the timer value T is not smaller than the predetermined time period T1 (step S67: NO), it is determined whether or not the engine speed N is higher than a second deceleration engine speed NR2 (step S69). The value of the second deceleration engine speed NR2 is smaller than the value of the first deceleration engine speed NR1. If it is determined that the engine speed N is higher than the second deceleration engine speed NR2 (S69: YES), the bypass valve drive device 57 is controlled so that the opening degree of the bypass valve 56 decreases to obtain an air-intake amount required to decrease the engine speed N by a second predetermined value ΔN2 (step S70). Then, the process returns to the main flow shown in
If it is determined that the engine speed N is not higher than the second deceleration engine speed NR2 (S69: NO), the flag value f is set to 2 (step S71). The bypass drive device 57 is controlled so that the opening degree of the bypass valve 56 is adjusted to obtain an air-intake amount required to maintain the engine speed N at the second deceleration engine speed NR2 (step S72). Then, the process returns to the main flow shown in
If it is determined that the flag value f is not 1 (in other words, the flag value f is 2) (S66:NO), the process moves to step S72, and the bypass valve drive device 57 is controlled to maintain the engine speed N at the second deceleration engine speed NR2. Then, the process returns to the main flow shown in
In a case where the rider wishes to decelerate the watercraft 1 and operates the deceleration operation member 34, the normal driving mode transitions to the deceleration mode at time t1 when the deceleration operation member 34 has moved from the first position to the second position. Just after the time t1 when the deceleration mode starts, the flag value f is 0, and the engine speed N has decreased to the idling engine speed NI in the illustrated example. Therefore, step S61, step S62, step S63, and step S64 are sequentially performed. In other words, the engine speed N increases according to the first predetermined value ΔN1. For example, the engine controller may be configured to control the engine such that an engine speed reaches a set value higher than an idling engine speed regardless of an operation of the driving power operation member. With an increase in the engine speed N, the water jet being ejected from the water jet pump 10 increases in speed, and the additional decelerative effect produced by the resulting reaction of the water jet is enhanced.
At time t2 when the engine speed N has reached the first deceleration engine speed NR1 which is higher than the idling engine speed NI set in the state where the deceleration operation member 34 is not operated, the flag value f is set to 1. Thereafter, step S61, step S66, step S67, step S68 and step S65 are sequentially performed during a predetermined time period T1. To be specific, during the predetermined time period T1, the opening degree of the bypass valve 56 is maintained at a first deceleration opening degree θR1 which is larger than the fully-closed position, and the engine speed N is maintained at the first deceleration engine speed NR1. In this state, the additional deceleration effect continues to be enhanced as described above.
After time t3 when the predetermined time T1 has lapsed, step S61, step S66, step S67, step S69 and step S70 are sequentially performed. That is, the engine speed N continues to decrease according to a second predetermined value ΔN 2. With a decrease in the engine speed N, the speed of the water jet being ejected from the water jet pump 10 gradually decreases, and the additional decelerative effect decreases. At time t4 when the engine speed N has reached the second deceleration engine speed NR2, the flag value f is set to 2. Thereafter, step S61, step S66, and step S72 are sequentially performed. To be specific, the opening degree of the bypass valve 56 is maintained at a second deceleration opening degree θR2 which is larger than the opening degree corresponding to the fully-closed position and is smaller than the first deceleration opening degree θR1, and the engine speed N is maintained at the second deceleration engine speed NR2.
As should be readily appreciated from the above, when the deceleration operation member 34 has been operated and the reverse driving operation member 33 is not operated, the bypass valve drive device 57 is controlled to open the bypass passage 55. In this way, the air-intake amount of the engine 6 can be ensured, in response to the rider's request for decelerating the watercraft 1, even when the driving power operation member 30 is in the first position and the throttle valve 54 is in the fully-closed position. This makes it possible to increase the speed of the water jet being ejected from the water jet pump 10. Therefore, the decelerative effect can be suitably produced using the reverse bucket 22.
Regarding an increase in the engine speed N just after time t1 and a decrease in the engine speed N just after time t3, a change rate of the increasing engine speed is set larger than a change rate of the decreasing engine speed when the engine speed N is changed in association with the operation of the deceleration operation member 34. To be specific, the first predetermined value ΔN1 in step S63 is set larger than the second predetermined value ΔN2 in step S70. This makes it possible to quickly enhance the additional decelerative effect just after the deceleration operation member 34 has been operated and to suitably avoid an undershooting phenomenon in which the engine speed N is lower than the suitable second deceleration engine speed NR2.
The engine speed N is increased after the reverse bucket 22 has reached a predetermined deceleration position after the deceleration operation member 34 has been operated. For example, the engine controller may be configured to start controlling the engine to cause the engine speed to be higher than the idling engine speed after the movement detector detects that the reverse bucket has reached the deceleration position. This makes it possible to suitably avoid a problem caused by an increase in the speed of the water jet during the movement of the reverse bucket 22, for example, smooth movement of the reverse bucket 22 is impeded by the high-speed water jet.
Alternatively, regarding the control executed when the deceleration operation member 34 has been operated, the bypass drive device 57 may be controlled to increase the engine speed after a lapse of a predetermined time after the deceleration operation member 34 has been operated. The control for decreasing the increased engine speed is not necessarily performed. The second deceleration engine speed NR2 may be higher than the first deceleration engine speed NR1. Although the set value of the engine speed N is switched with reference to the timer value T, other driving parameter(s) may be used.
The deceleration engine speed may be a predetermined single constant value. The increase amount of the engine speed with respect to the idling engine speed may be suitably changed according to the driving state parameter such as a driving speed, and the deceleration engine speed may be suitably set and changed. In this case, the increase amount may be set to a larger value as the driving speed is higher. This can produce a higher deceleration effect as the driving speed is higher.
The three operation members 30, 33 and 34 are not necessarily lever-type operation members. For example, the reverse driving operation member 33 and the deceleration operation member 34 may be button-type members. Although the reverse driving operation member 33 and the deceleration operation member 34 may be positioned near the left grip 32 of the handle 20 to enable the rider to easily operate them while touching the left grip 32 to improve steering stability, they may be positioned anywhere else in the handle 20.
Although the deceleration operation sensor 76 may be configured to detect that the deceleration operation member 34 has reached the second position, it may be configured to detect whether or not the deceleration operation member 34 has been operated a predetermined amount or larger from the first position. The same may occur in the reverse driving operation sensor 75.
[Embodiment 2]
The throttle device 127 of this embodiment shown in
The personal watercraft of Embodiment 2 does not include the coupling mechanism 35 shown in
If it is determined that the reverse driving operation member 33 is not operated in step S101 (S101: NO), it is determined whether or not the deceleration operation member 34 has been operated (step S105). If it is determined that the deceleration operation member 34 has been operated (5105:YES), it is determined whether or not the reverse bucket 22 has reached the deceleration position based on the detection value of the bucket position sensor 178 (step S106). If it is determined that the reverse bucket 22 has reached the deceleration position (S106: YES), the driving power and engine speed of the engine 6 are controlled according to the deceleration mode as in Embodiment 1 (step S6), and then the process returns to step S101. If it is determined that the reverse bucket 22 has not reached the deceleration position (step S106: NO), the bucket actuator 182 is controlled to move the reverse bucket 22 toward the deceleration position (step S107), and step S5 and step S103 are performed as in the case where the reverse bucket 22 moves to the reverse driving position. Then, the process returns to step S101.
If it is determined that the deceleration operation member 34 is not operated in step S105 (S105: NO), the bucket actuator 182 is controlled to move the reverse bucket 22 to the forward driving position (step S108), and step S5 and step S103 are performed as in the above case. Thus, the process terminates.
In Embodiment 2, also, when the normal driving mode transitions to the deceleration mode (S6), the control process is executed along the flow shown in
The personal watercraft of the present invention may be configured to include the throttle device 127 of Embodiment 1 and the electric reverse bucket 22 of Embodiment 2. Alternatively, the personal watercraft of the present invention may be configured to include the throttle device 127 of Embodiment 2 and the wire-driven reverse bucket 22 of Embodiment 1.
As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiments are therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.
Number | Name | Date | Kind |
---|---|---|---|
5813357 | Watson | Sep 1998 | A |
6350163 | Fujimoto | Feb 2002 | B1 |
6691634 | Fritchle | Feb 2004 | B2 |
7007621 | Bootes | Mar 2006 | B1 |
7052338 | Morvillo | May 2006 | B2 |
Number | Date | Country |
---|---|---|
2004196041 | Jul 2004 | JP |
Number | Date | Country | |
---|---|---|---|
20110244737 A1 | Oct 2011 | US |