Steering System Heat Management for Azimuthing Propulsion
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Solution Overview
Problem
Azimuthing propulsion systems face heating issues due to over torque situations, particularly in arctic environments where smaller hydraulic motors are used, leading to increased rotation speed and reduced heat absorption capacity.
Innovation Solution
A steering system with a separate hydraulic overload protection unit that includes a pressure relief valve and a heat management unit featuring a temperature balance tank, which absorbs heat generated during over torque situations by circulating fluid through a heat sink or cooler, allowing the propulsion unit to turn with colliding objects without overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If smaller hydraulic motors are used to reduce weight and cost, then weight and dimensions are reduced, but heat absorption capacity is reduced leading to overheating during over torque situations
Solution Approach 1:
A temperature balance tank is introduced as an intermediary component between the hydraulic motor and the pressure relief valve. This tank acts as a heat sink that absorbs excess heat generated during over torque situations, allowing the use of smaller hydraulic motors without compromising the system's thermal management capability.
Solution Approach 2:
The system converts the harmful effect of heat generation during pressure relief into a beneficial thermal management mechanism. The temperature balance tank captures the heat that would otherwise cause overheating, and uses it to pre-heat the hydraulic fluid before it enters the motor, improving efficiency while preventing overheating.
2Power
If hydraulic motors operate at increased rotation speed to compensate for smaller size, then power output is maintained, but heat generation increases leading to overheating
Solution Approach 1:
The system converts the harmful heat generated by high-speed operation into a beneficial pre-heating effect. The temperature balance tank captures heat from the pressure relief valve outlet and uses it to pre-heat the fluid before it enters the motor, reducing the temperature differential and overall heat generation while maintaining power output.
Solution Approach 2:
The system changes the temperature parameter of the hydraulic fluid through the temperature balance tank. By pre-heating the fluid before it enters the motor and cooling it after pressure relief, the system optimizes the thermal parameters to reduce overall heat generation while maintaining the required power output at high rotation speeds.
3Reliability
If pressure relief valves are used to protect against over torque, then system reliability is improved, but heat is generated that can cause overheating
Solution Approach 1:
The temperature balance tank serves as an intermediary between the pressure relief valve and the hydraulic motor. It captures the heat generated during pressure relief operations and uses it to pre-heat the fluid before it enters the motor, thereby maintaining reliability protection while eliminating the overheating problem.
Solution Approach 2:
The system converts the harmful heat generation from pressure relief into a beneficial pre-heating mechanism. The heat that would normally be wasted and cause overheating is instead captured and used to pre-heat the hydraulic fluid, improving system efficiency while maintaining the protective function of the pressure relief valve.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the use of smaller, more compact hydraulic motors, reducing weight, dimensions, and costs while maintaining system performance, and preventing overheating during over torque events, suitable for arctic vessels and ice breakers.
Implementation Method 1
the temperature balance tank is configured to receive a heated outlet fluid flow of the pressure relief valve and to provide a filling fluid flow to a hydraulic motor inlet volume so that the fluid cycle comprising the overload protection unit is configured to at least partially absorb heat generated during turning of the propulsion unit
Data Source
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AI summary
According to an example aspect of the present invention, there is provided a steering system (30) of an azimuthing propulsion system (1), the steering system (30) comprising at least one hydraulic motor (2) configured to operate an azimuthing system of a propulsion unit (3), the propulsion unit (3) being arranged outside a vessel, a fluid cycle (4) from the at least one hydraulic motor (2) via a separate hydraulic overload protection unit and back to the motor (2), the overload protection unit comprises a pressure relief unit and a heat management unit, and wherein the pressure relief unit comprises a pressure relief valve (5), andthe heat management unit comprises a heat storage, a heat exchanger, or a combination of both, and wherein the fluid cycle (4) comprising the overload protection unit (32) is configured to at least partially absorb heat generated during turning of the propulsion unit (3).