EXHAUST FOR OUTBOARD JET PROPULSION ENGINE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application is a Non-Prov of Prov (35 USC 119(e)) application of Provisional Application No. 60/751 ,700 filed on December 19, 2005.

BACKGROUND OF THE INVENTION

[0002] This invention is related to an exhaust for an outboard jet propulsion engine, and in particular, a bucket for exhausting the water jet when driving the associated craft in the reverse direction.

[0003] It is known in the art to utilize an outboard jet propulsion engine to drive a boat. As known from applicant's co-pending U.S. Application No. 10/988,327, filed September 14, 2005 entitled OUTBOARD JET DRIVE MARINE PROPULSION SYSTEM (the "327 application") water is driven through a housing, the force of the exiting jet of water moving the boat in the forward direction. A bucket assembly is mounted at the jet exhaust so as to selectively move from a first position to a second position between covering the exhaust and keeping clear of the exhaust. As the bucket assembly covers an exiting water jet, it diverts the direction of the water jet to move the boat in the reverse direction.

[0004] Making reference to Figs. 1 A and 4A, a prior art bucket assembly generally indicated as 10 includes bucket housing 12 adapted to be mounted downstream of the water jet exhaust of the jet drive unit. A bucket 14 is rotatably mounted on bucket housing 12 so as to selectively close a first exhaust at an exit end of bucket housing 12 as seen in Fig. 2A. As the jet exiting the jet drive unit hits upon an interior surface 16 (Fig. 1A) of bucket 14, the water is blocked from exiting the first exhaust and is deflected through exhaust plenum 22 on either side of bucket 14.

[0005] Plenums 22 extend from bucket 14 and are in communication with the interior of bucket 14 on either side of bucket 14 (see Figs. 1A and 3A) to also provide an escape for water deflected against interior back surface 16 of bucket 14. The exhausts of plenum 22, are substantially coextensive with the bucket and exhaust .

water in a direction generally back and towards the lower surface of housing 12 when bucket 14 is in the closed position. In this way, water is pushed back towards the boat - having a net effect of pushing the boat in the reverse direction.

[0006] This structure has been satisfactory for reversing the boat under the control of a jet propulsion engine. However, it suffers from the disadvantage that power is lost when the engine is required to make tight turns in the reverse direction; particularly in the type of movements required by a tugboat, i.e., tight quick turns under high power. As known from the '327 application, steering of a boat utilizing the jet propulsion engine is accomplished by moving the direction of the jet, i.e., movement of the bucket and exhaust port about a pivot point 30 relative to the remainder of the housing or the boat. During tight maneuvers, one of plenums 22 became blocked by the structure of the boat, reducing the effective power of the engine. Additionally, water jets exiting plenums 22 quickly lost their cohesion and in effect their power.

[0007] Furthermore, it was discovered that the gas exhaust from the engine housed within the jet propulsion housing was producing bubbles as it exited the housing, which was interfering the optimal operation of the jet engine as a result of cavitation.

[0008] Accordingly, an improved bucket assembly and exhaust system is desired which overcomes the deficiencies of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Objects, features of the present invention will be apparent from the written description in which:

[0010] FIG. 1A is a front perspective view of a bucket assembly constructed in accordance with the prior art;

[0011] FIG. 1 B is the comparable perspective view of a bucket assembly constructed in accordance with the invention;

[0012] FIG. 2A is a side elevational view of a bucket assembly constructed in accordance with the prior art;

[0013] FIG. 2B is the comparable elevational view of a bucket assembly constructed in accordance with the invention;

[0014] FlG. 3A is a front perspective view showing a prior art bucket assembly;

[0015] FIG. 3B is a comparable front perspective view of a bucket assembly constructed in accordance with the invention;

[0016] FIG.4A is a rear elevational view of a prior art bucket assembly in the closed position;

[0017] FIG. 4B is a rear elevational view of a bucket assembly constructed in accordance with the invention in the closed position;

[0018] FIG. 5 is a side elevational view of a bucket assembly mounted on a jet propulsion engine in a substantially open position constructed in accordance with the invention;

[0019] FIG. 6 is a rear perspective view of the housing and bucket assembly, constructed in accordance with the invention;

[0020] FIG. 7 is a side elevational view of the bucket assembly constructed in accordance with the invention in the open position;

[0021] FIG. 8 is a first side elevational view of a housing and bucket assembly constructed in accordance with another embodiment of the invention;

[0022] FIG. 9 is a rear elevational view of the housing and bucket assembly in the closed position constructed in accordance with the invention of FIG. 8;

[0023] FIG. 10 is front elevational view of a housing and bucket assembly in the closed position constructed in accordance with the invention of FIG. 8;

[0024] FIG. 11 is a bottom plan view of the housing and bucket assembly in the closed position constructed in accordance with the invention of FIG. 8;

[0025] FIG. 12 is a top plan view of the bucket assembly in the closed position constructed in accordance with the invention of FIG. 8;

[0026] FIG. 13 is a side elevational view of the opposite side of bucket assembly in a closed position constructed in accordance with the invention of FIG. 8;

[0027] FIG. 14 is a sectional view taken along line 14-14 of FIG. 8. and

[0028] FIG. 15 is a first side elevational view of a housing and bucket assembly in the open position constructed in accordance with the invention of FIG.8.

DETAILED DESCRIPTION OF THE INVENTION

[0029] Reference is made to Figs. 1 B, 2B, 3B and 4B in which a bucket assembly, generally indicated as 100, is shown. Bucket assembly 100 includes a bucket housing 104. A bucket 102 is rotatably mounted on bucket housing 104. Bucket housing 104 is in communication with a water exhaust of the jet propulsion engine so as to receive water existing the water exhaust (not shown). Bucket housing 104 has an entrance port 106 and a first exhaust 108 (Fig. 7), seen at an opposed end of housing 104 for allowing water to exit bucket housing 104 when bucket 102 is in the open position.

[0030] An exhaust assembly, generally indicated as 110, provides a second exhaust. The exhaust assembly 110 has a first vent 112 and a second vent 114. Vent 112 extends along a first axis and vent 114 extends along a second access so that the first axis intersects the second axis, i.e. vent 114 is angled relative to vent 112. When bucket 102 blocks water from exiting exhaust 108, it also places vents 114, 112 are in communication with the interior of bucket housing 104 to allow water to exit when bucket 102 is in the closed position.

[0031] A bucket linkage 124 is connected to bucket 102. A reverse cable 126 which controls linkage 124, rotates bucket 102 to a first position in which bucket 102 is open (Fig. 5, Fig. 6) to allow water to pass through exit port 108. Linkage 124 . also controls bucket 102 to move in a direction to close exit port 108 and redirect the

water path through first and second vents 112, 114 of bucket housing 104 to guide the water in a direction substantially back towards the jet propulsion engine housing 202.

[0032] In a preferred embodiment, bucket housing 104 has a substantially circular body. Vents 112, 114 are disposed along the circumference of bucket housing 104, away from a bottom 140 of bucket housing 104 and on opposed sides of a pivot axis 119 extending through bucket housing 104.

[0033] The angle formed between vent 112 and vent 114 should be sufficient to divert water at an angle to flow around a boat to which exhaust assembly 110 is attached. In a preferred non-limiting embodiment, the angle formed by the intersection of the axes along which vents 112 and 114 lie is about 34°. Accordingly, in the closed position, water enters bucket housing 104 in a direction towards bucket 102. When in the closed position, water is deflected by bucket 102 substantially reversing direction out through first and second vents 112, 114. When in the open position, water will flow directly through exit port 108 of bucket housing 104.

[0034] Bucket 102 is substantially curved so as to be convex (Fig. 4) providing room for water traveling through bucket housing 104 to travel towards first and second vents 112, 114 as well as providing a surface which facilitates the substantially unimpeded deflection of water in the reverse direction; namely the convex curve.

[0035] First and second vents 112, 114 are in fluid communication with each other when bucket 102 is in the closed position. Accordingly, if during tight maneuvers either one of first and second vents 112, 114 becomes closed against the jet unit structure, the pressure of the water exiting the unblocked vent is increased. In this way, thrust sufficient to perform the tight maneuver is maintained. In this way, the jet propulsion engine is self-adjusting.

[0036] Furthermore, bucket 102 includes a first plenum 130 and a second plenum 132 in communication with the interior of bucket housing 120 to provide a third exhaust for the water jet when bucket 102 is in the closed position. Plenums 130, 132

preferably extend a length between extending beyond bucket 102 and to at least a bottom surface 140 of bucket housing 104 when the housing is in a closed position.

[0037] Plenums 130, 132 substantially reside in a plane. Secondary exhausts 112, 114 substantially reside in a second plan, the first plane intersecting the second plane at a substantially obtuse angle. In this way, the water exiting the plenums 130, 132 and the secondary events avoid housing 200.

[0038] Furthermore, as the result of the longer plenum run, the jet remains more cohesive as it exits plenum 130, 132. Additionally, by releasing the jet at a point at least at the bottom of bucket housing 104, the boat and/or housing are less likely to interface with the jet thrust, increasing overall thrust.

[0039] A secondary problem is cavitation that is air bubbles being trapped in the jet stream intake. The air bubbles are formed from the exhaust of the engine from the housing.

[0040] Reference is now made to Fig. 7 in which structure for diverting air bubbles in accordance with anotehr embodiment of the invention is provided. A housing for an engine for driving the jet propulsion unit as known from U.S. Application No. 10/988,327 and incorporated as if fully detailed herein, generally indicated at 200, includes sidewalls 202. Exhausts are formed as elongated channels 204 extending along a lower portion of sidewall 202. Channels 204 are operatively coupled to the exhaust of the engine of the jet propulsion system. In this way, the bubbles are diverted beyond the intake of the jet propulsion drive.

[0041] Reference is now made to Figs. 8-15 in which an alternative embodiment of the invention is provided. The primary difference between the bucket assembly shown in this embodiment and those shown in Figs. 1B-7, is that the vents 112, 114 have been replaced by an exhaust disposed within the bottom of the housing; the exhaust including vanes for directing the water. As known from co-pending application U.S. Serial No. 10/988,327, the bucket assembly is moved from the open to the closed position by a vertical cable 126. However, it has been determined that in a preferred embodiment, the length of the cable, to achieve maximum result, must be

relatively short given the length of the entire control assembly. In a preferred embodiment, the cable length extending in the vertical direction is about three inches. Because of this small throw distance, a bucket assembly must be designed to move the entire bucket so that the entire bucket is substantially clear of the output of the water jet when the bucket is in the open position to allow propulsion of the boat in a forward direction.

[0042] Furthermore, to reduce draft on the boat, it is desirable to have a venting mechanism for the housing which is not disposed on the outside of the housing as with vents 112, 114. Accordingly, this embodiment is a more streamlined embodiment which still directs water back towards the boat to create reverse thrust but angles substantially all of the exiting water jet below the boat so as not to reduce the thrust of the water jet.

[0043] Reference is now had to another embodiment of the bucket assembly, generally indicated as 300 and constructed in accordance with the invention. Like structure is indicated by like numerals for ease of description. Bucket assembly 300 includes a bucket housing 304, a bucket 302 is rotatably mounted on bucket housing 304. Bucket housing 304 is in communication with the water exhaust of the jet propulsion engine to receive water exiting the water exhaust as described above. Bucket housing has an entrance port 106 and an exhaust 108 at an opposite end of bucket housing 304.

[0044] An exhaust assembly, generally indicated as 310 is formed with housing 304. Exhaust assembly 310 includes an exhaust frame 314 and directional vanes 316 and 318 disposed within frame 314. Vane 316 extends across frame 314 and is formed at an angle relative to the plane of the bottom of the boat (not shown) to form an angle of less than 90° therewith, but greater than 1° so as to direct water exiting through exhaust 310 towards the boat but below the plane in which the bottom of the boat resides. Frame 314 holds vanes 316, 318 in place so that the entire venting assembly 310 form a structure which is in fluid communication with the interior of housing 304. As seen in Fig. 14, vanes 316, 318 intersect each other and form a plurality of first plenums 340.

[0045] During operation, water flows in the direction of arrow A through housing 304. When bucket 302 is in the closed position, it deflects water in the direction of arrow B, as a result of its curved surface towards vanes 316, 318 (Fig. 14). Because of the curved surface of bucket 302, water traveling in the direction of arrow B does not interfere with water traveling in the direction of arrow A reducing turbulence and providing greater efficiency of thrust out of the bucket assembly in the direction substantially of arrow C back towards the boat and down. In this way, the jet stream used to propel in the reverse direction does not interfere with the boat. Additionally, water is directed to the sides of the plenum (into the page and out of the page of Fig. 14) to exit through first plenum 330 and a second plenum 332.

[0046] Bucket 302 includes a second plenum and a third plenum 332 in communication with the interior of the bucket housing 304 to provide a third exhaust for the water jet when bucket 302 is in the closed position. Plenum 330, 332 extend to be at least coextensive with the bucket 302 but a preferred embodiment extends a distance from beyond bucket 302 to at least a bottom surface 346, each plenum 330, 332 has respective exhaust opening 352, 354. Furthermore, plenums 330, 332 are tapered towards exhaust 352, 354.

[0047] Like plenums 130, 132, plenums 330, 332 are formed at an angle relative to a bottom 346 of housing 304 to direct water existing plenum exhaust 352, 354 towards the boat hull but down to avoid the jet from being deflected against the boat hull.

[0048] It should also be well understood, as shown in Fig. 15, when bucket 302 is in the open position water moving in the direction of arrow A passes through exit port 108 and does not get deflected through plenum 340. In this way, the boat is pushed in the forward direction in accordance with the invention.

[0049] It should be noted that plenums 330, 332 are formed of an outer wall 360 of bucket assembly 302. A front wall 362 which may be formed of a single unitary piece across the entire bucket assembly 302 or individual pieces, and an interior sidewall 364 which slides along frame 314 (however, the outer wall of frame 314 may

also be used to form a wall of the plenum). It is this entire assembly which is lifted when bucket 302 is in the open position as shown in Fig. 15.

[0050] By providing vanes within frame 314 at the exhaust, there is a greater surface area along the traveled path which focuses the water, cuts down on turbulence and increases the pressure of the exiting water. Similarly, by tapering plenums 330, 332, the pressure of the water is increased as the cross section of the plenum decreases. Furthermore, the longer the plenum, the more directed and focused the water column becomes exiting in the direction of arrow D (Fig. 14). Again, substantially in the direction towards, but down, relative to the boat to which the jet propulsion system is attached.

[0051] Thus, while there have been shown, described and pointed out novel features of the present invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and change in the form and detail are contemplated so that the disclosed invention may be made by those skilled in the art without departing from the spirit and scope of the invention. It is the intention therefore to be limited only as indicated by the scope of the claims appended hereto. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which as a matter of language, might be said to fall there between.