Outboard Marine Corporation

Bombardier Motor Corporation of America

Applied Combustion Technology, Inc.

A Michael Varney

John D Martino

Kimball P Hall

A marine outboard motor includes a power unit and a pump jet. The power unit includes a drive output and an exhaust outlet, and the pump jet includes a rotor hub and a rotor carried thereby. The rotor hub is connected to the drive output of the power unit for selective rotation for forward or reverse motion, and the rotor hub has an internal passageway connected in fluid communication with the exhaust outlet. The pump jet further includes an exhaust bypass movable between normal and bypassed positions. The exhaust bypass when in the normal position directing exhaust through the internal passageway of the rotor hub to discharge downstream of the rotor during forward motion. The exhaust bypass when in the bypassed position bypassing exhaust from the internal passageway to discharge downstream of the rotor during reverse motion.

Pump jet with an exhaust bypass and associated methods

A pump jet having a perforated wear liner inside the rotor housing for altering the spectrum of noise produced by the pump jet. The perforated wear liner is inserted in a circumferential recess formed on the inner surface of the rotor housing and surrounds the rotor tip region. The throughholes or perforations are preferably constant in size and regularly spaced. The perforated wear liner acts as a Helmholtz resonator liner which alters the spectrum of noise emitted from the pump jet during operation. Proper selection of the size, number and spacing of the holes permits the designer to control the specific noise spectrum range that is emitted from the front and rear lobes of the pump jet, thereby altering the hydrodynamic noise field.

Pump jet rotor housing modification for noise signature spectral control

A pump jet in which the axial flow of water through the device is controlled by bleeding exhaust gas into the pump jet water stream, thereby producing a thrust loss. The addition of gas into the primary pump jet water flow stream reduces the effective flow density of the exit media, thereby reducing the exit momentum (and thrust) produced by the pump jet. The thrust modulation device can be actuated using any conventional electrical or mechanical actuation subsystem via a knob or lever positioned near the throttle control.

Pump jet with axial directional flow control device for thrust modulation

An ETV-type pump jet having a stator housing with an attachment for minimizing the mismatches between the velocity and direction of the exhaust gas stream flowing out of a stator vane outlet and the velocity and direction of boat and pump jet motion. In one embodiment, a multiplicity of exhaust ducts are attached to the external surface of the stator housing, each exhaust duct being positioned to be in flow communication with the exhaust gas outlet of a respective hollow stator vane. Exhaust gases exiting the exhaust outlets are redirected by the inner surfaces of the ducts to flow in parallel with the rotor shaft axis. In another embodiment, a circumferential exhaust skirt made of sheet metal is substituted for the exhaust ducts. The exhaust skirt surrounds the stator housing and redirects the exhaust gas stream to be substantially parallel with the surrounding water flow.

Pump jet with redirected exhaust gas through stator vane for drag reduction

A pump jet apparatus having a double-walled stator housing containing an annular passage through which exhaust gas can flow. Gas enters the annulus through an exhaust gas inlet or port formed in the outer stator shell at the top of the stator housing, flows in two streams around the annular passage formed between the inner and outer stator shells, and exits the stator housing through exhaust outlets or ports formed in the outer stator shell near the bottom of the stator housing. The streams of exhaust gas and impelled water flowing through the stator housing of the pump jet are kept separate by the inner stator shell.

Pump jet with double-walled stator housing for exhaust noise reduction

A marine pump jet includes a rotor located upstream and in front of the rotor drive mechanism. The lower unit of the tractor pump jet has a rotor housing which substantially surrounds the rotor and a stator housing located downstream of the rotor and rotor housing. A drive shaft extending from an upper gear case enters the stator hub where a pinion gear engages a crown gear attached to the rotor shaft. This places the rotor drive mechanism downstream of the rotor so that the rotor is substantially the first mechanical element that water initially comes into contact with. The inlet opening of the pump jet is larger than the outlet opening at the outlet of the stator housing. Because the rotor operates on essentially undisturbed, non-turbulent water, it is more efficient than traditional pump jets where the rotor is located aft of the drive mechanism. The upper gear case includes a reverse shifting mechanism that permits the tractor pump jet to operate in either the forward or reverse direction.

Tractor pump jet

A marine pump jet includes a rotor located upstream and in front of the rotor drive mechanism. The lower unit of the tractor pump jet has a rotor housing which substantially surrounds the rotor and a stator housing located downstream of the rotor and rotor housing. The drive shaft extending from the power head enters the stator hub where a pinion gear engages a crown gear attached to the rotor shaft. This places the rotor drive mechanism downstream of the rotor so that the rotor is substantially the first mechanical element that water initially comes into contact with. The inlet opening of the pump jet is larger than the outlet opening at the outlet of the stator housing. Because the rotor operates on essentially undisturbed, non-turbulent water, it is more efficient than traditional pump jets where the rotor is located aft of the drive mechanism. According to an alternative embodiment, a reverse shifting mechanism permits the tractor pump jet to operate in either the forward or reverse direction.

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Sewall's Point, FL, United States of America

A Michael Varney