BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to ship propulsion systems, and more particularly to a built-in propulsion system.

2. Description of the Related Art

The general marine thruster mainly uses the engine to drive the propeller for high-speed operation. When the propeller is running at high speed, each blade will push the water flow backwards, and the reaction force generated when the water flow pushes back is used as the propulsion power of the hull, and the steering of the hull is controlled by the left and right deflection of the rudder.

Because the conventional propeller has a deep draught, the effective propulsion component generated by the rotation of the propeller when the boat is sailing is small and the propulsion efficiency is low. Secondly, the exhaust gas generated by the engine will be discharged through the shaft hole of the propeller hub, so that the water flow driven by the propeller and the exhaust gas generated by the engine easily interfere with each other at the water outlet to form a turbulent flow. As a result, the resistance of the propeller during operation becomes larger and the thrust applied to the hull is weakened, resulting in a reduction in propulsion efficiency. In addition, the propeller and the rudder are exposed at the bottom of the hull, which is easy to collide with foreign objects when the boat is sailing, or easy to entangle with foreign objects (such as plastic bags or fishing nets) during rotation to cause damage.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a built-in propulsion system, which can improve the propulsion efficiency.

To achieve this and other objects of the present invention, a built-in propulsion system comprises an engine, a diversion unit and a propulsion unit. The diversion unit comprises a diversion base and an exhaust pipe. The diversion base is located at a bottom end of the engine, comprising a water inlet located at a front end thereof, a water outlet located at an opposing rear end thereof, a diversion channel defined therein and having two opposite ends thereof respectively disposed in communication with the water inlet and the water outlet, a shaft hole, and an exhaust chamber. The shaft hole is located above the water inlet and communicated with the diversion channel. The exhaust chamber is located behind the shaft hole and fixed with a top end thereof on the outer periphery of the diversion base in communication with the exhaust chamber of the diversion base. The propulsion unit comprises a transmission shaft and an impeller connected to the transmission shaft. The transmission shaft is rotatably inserted through the shaft hole of the diversion base and connected to the engine. The impeller is located in the diversion channel of the diversion base above the water inlet of the diversion base. Thus, the power generated by the engine will drive the impeller to rotate through the transmission shaft.

It can be seen from the above that when the impeller rotates, the water flow is first drawn into the diversion channel. Then, after the rectification effect of the impeller, the water flow is ejected backward from the water outlet to advance the boat. During the operation of the engine, the exhaust gas generated by the engine will be concentrated in the exhaust chamber of the diversion base and then discharged from the exhaust pipe to the outside of the diversion base. This can effectively prevent the exhaust gas from interfering with the water flow through the diversion channel, thereby improving the propulsion efficiency.

Preferably, the water inlet has the opening thereof facing downward. The diversion unit further comprises a water inlet block located on a bottom surface of a front end of the diversion base below the water inlet. The water inlet block comprises a plurality of first diversion holes located on a front end thereof in communication with the water inlet, and a plurality of second diversion holes located on a bottom surface thereof in communication with the water inlet. With the setting of the first diversion holes and the second diversion holes, the water flow can be effectively guided into the diversion base through the water inlet block.

Preferably, the water inlet block comprises a plurality of arc-shaped deflectors arranged at intervals on the bottom surface thereof. With the setting of the arc-shaped deflectors, the water flow can be effectively guided from the second diversion holes into the diversion channel.

Preferably, the diversion base further comprises a ring wall surrounding the impeller so that the impeller can be completely covered. The arrangement of the ring wall not only can improve the water inlet efficiency, but also can make the impeller less harmful to fish, swimmers or divers near the bottom of the boat. Therefore, it can also be applied when the draft of the boat is shallow.

Preferably, the diversion unit further comprises a reverse deflector pivotally connected to the rear end of the diversion base and biasable up and down relative to the diversion base. When the reverse deflector is located above the water outlet, the water flow from the water outlet is directly ejected backward, making the boat forward. When the reverse deflector is located behind the water outlet, the water flow from the water outlet is changed by the reverse deflector to spray to the front, causing the boat to retreat.

Preferably, the reverse deflector comprises two lugs respectively located at opposing left and right sides thereof. The two lugs have a respective front end thereof respectively pivoted to the rear end of the diversion base. The diversion unit further comprises a rocker and a link. The rocker is pivoted back and forth on the outer peripheral surface of the diversion base. The link has a front end thereof pivoted on a bottom end of the rocker, and an opposing rear end thereof pivoted on a rear end of one lug of the reverse deflector. With the above technical features, when the rocker is driven by the power source, it can pull or push the reverse deflector through the link, so that the reverse deflector can be switched between the upper and lower positions.

Preferably, the diversion unit further comprises a tension spring. The tension spring has two opposite ends thereof respectively connected to the rocker and the reverse deflector, which can provide elastic force to help the link pull the reverse deflector from the second position to the first position.

Preferably, the exhaust pipe has a bottom end thereof open downward, which can surely prevent the exhaust gas of the engine from interfering with the water flow discharged from the water outlet.

The detailed structure, characteristics, assembly or use of the built-in propulsion system provided by the present invention will be described in the detailed description of the subsequent preferred embodiment. However, those with ordinary knowledge in the field of the present invention should be able to understand that these detailed descriptions and specific embodiments listed in the implementation of the present invention are only used to illustrate the present invention, not to limit the scope of the patent application of the present invention.

