Multi-speed Gearbox for Low Spool Auxiliary Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern airplane engines face inefficiencies in extracting electric power from high pressure spools, necessitating specialized generators for low pressure spools due to significant speed differences, which increases costs and reduces efficiency.
Innovation Solution
A gearbox system with first and second clutches and output gears driven by an input shaft from a low spool turbine engine, allowing selective engagement of clutches to adjust rotational speeds for an auxiliary component like a generator, using an actuator controlled by a controller to manage speed transitions and prevent overrunning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power is extracted from the high pressure spool to drive a generator, then electric power is generated, but engine efficiency drops to an unacceptable level
Solution Approach 1:
The patent applies dynamics by making the gearbox capable of switching between different gear ratios (first and second gear ratios) based on operating conditions. The selectable gear ratio mechanism allows the system to adapt the transmission ratio between the low pressure spool and generator dynamically, optimizing power extraction efficiency across different engine operating points while maintaining acceptable engine efficiency.
Solution Approach 2:
The patent changes the transmission ratio parameter by providing at least two different gear ratios through the gearbox. This allows the system to optimize the speed and torque relationship between the low pressure spool and generator, enabling efficient power extraction across varying operating conditions without compromising engine efficiency.
2Power
If a generator is designed for use with the faster low spool to achieve desired electrical output, then electrical power is generated, but specialized equipment is required increasing cost
Solution Approach 1:
The gearbox acts as an intermediary between the low pressure spool and the generator. It mediates the speed mismatch by providing gear reduction, allowing a standard generator designed for lower speeds to be used with the faster low pressure spool. This eliminates the need for specialized high-speed generator designs and reduces overall system cost.
Solution Approach 2:
The gearbox changes the rotational speed parameter through gear reduction. By providing at least two selectable gear ratios, it transforms the high-speed rotation of the low pressure spool into appropriate speed ranges for standard generators, enabling use of conventional equipment rather than specialized high-speed designs.
3Power
If the low pressure spool drives the generator directly, then power extraction is available, but the speed range is significantly higher requiring specialized generator design
Solution Approach 1:
The gearbox serves as a speed-matching intermediary between the low pressure spool and generator. It reduces the significantly higher rotational speed of the low pressure spool to appropriate levels for standard generators through gear reduction, enabling direct power extraction without requiring specialized high-speed generator designs.
Solution Approach 2:
The selectable gear ratio mechanism provides dynamic speed adjustment capability. The system can switch between different gear ratios to match the generator's optimal operating speed range with the varying speed of the low pressure spool, optimizing power extraction across different operating conditions.
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
Enables efficient and cost-effective power extraction from low pressure spools by allowing generators to operate within optimal speed ranges, reducing the need for specialized equipment and improving overall engine efficiency.
Implementation Method 1
the first clutch is an overrunning clutch, and the gearbox is configured such that the first clutch is rotationally overrun in response to engagement of the second clutch
Data Source
Figure 1~2
Figure 3~4
AI summary
A turbine engine power generation system includes a gearbox (43) that receives rotational drive from a low spool (14) through an input gear, in one example. The gearbox includes first and second clutches (58, 60) that are coupled to an input shaft (62) of an auxiliary component (64), such as a generator. First and second output gears (54, 56) are driven at different rotational speeds by the input gear (46, 48) and respectively associated with the first and second clutches. An actuator (66) selectively engages at least one of the first and second clutches to select between first and second rotational speeds in response to a command from a controller (74)