Designed Marine Hydrostatic Prop Drive
Problem:
Existing mechanical prop drive systems have the following limitations:
- Mechanical drive systems are inherently inefficient.
- Engine placement is fixed.
- High knots require high engine RPM.
- Low speed docking maneuvers are accomplished with plugging (bumping) the mechanical transmission in and out.
- Finding the “sweet spot” where engine torque, RPM and fuel economy coincide is nearly impossible.
Process:
- An engine was selected and an operating RPM was identified by the correlation of the torque, RPM, fuel efficiency curves.
- The engine was given two operating RPM’s. A docking (low) RPM and an Operating (high) RPM. Prop speed was varied by controlling the hydrostatic drive.
Results:
- Fuel Efficiencies Increased
- Hydrostatic drives are 10-15% more efficient than mechanical drives.
- By operating the engine at a constant RPM, the engine mass does not have to be accelerated.
- By operating an engine at a constant RPM the exhaust is able to be tuned and engine performance is significantly increased.
- Engine Noise Reduced
- By operating an engine at a constant RPM the exhaust is able to be tuned producing significantly quieter operation.
- Engine Placement is Infinite and Dynamically Variable
- Effective use of limited space is now available.
- Balancing non symmetrical loading is possible.
- Dynamic movement of the engine is possible during operation allowing maneuvering assistance and variation of wetted surface area.
- Docking Control Dramatically Improved
- Hydrostatic drives are able to deliver power and speed in a smooth infinitely variable operation.