Compound Engine Shaft Synchronization for Smooth Clutch Engagement
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Solution Overview
Problem
Existing systems for coupling internal combustion engines to accessories and rotatable loads face challenges in efficiently managing rotational speeds and engaging/disengaging mechanisms, particularly in scenarios where accessories need to be driven independently of the rotatable load, such as in aircraft applications, leading to issues like clutch wear and undesirable vibrations.
Innovation Solution
A method involving a gearbox with a clutch that allows the engine shaft and turbine shaft to rotate independently and engage/disengage, with a compound cycle engine system using a turbine and compressor to drive accessories and loads, and a speed matching process to synchronize rotational speeds before engagement, enabling efficient power compounding and reducing wear on clutch components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the engine shaft and turbine shaft are directly engaged without speed synchronization, then the engagement process is simple, but clutch wear increases and vibrations occur
Solution Approach 1:
The patent applies preliminary action by synchronizing the rotational speeds of the engine shaft and turbine shaft before engagement. The control system monitors both shaft speeds and adjusts them to match prior to clutch engagement, preventing shock loads and reducing wear. This speed matching process occurs in advance of the actual engagement event, resolving the contradiction between simple engagement and reliable operation.
2Productivity
If the accessories are driven independently from the rotatable load, then the accessories can operate at optimal speeds, but the system complexity increases
Solution Approach 1:
The patent applies segmentation by separating the drivetrain into independent shaft systems - the engine shaft directly coupled to accessories, and the turbine shaft coupled to the rotatable load. This allows each shaft to rotate at its own optimal speed independently. The clutch mechanism provides selective coupling between these segmented systems, enabling accessories to operate efficiently while the load receives power from the turbine, thus resolving the contradiction between productivity and complexity.
3Loss of time
If the engine shaft rotational speed is increased rapidly to match turbine shaft speed, then the synchronization time is reduced, but mechanical stress on components increases
Solution Approach 1:
The patent applies dynamics by implementing a controlled, progressive speed adjustment process rather than rapid changes. The control system dynamically modulates the engine shaft speed to gradually approach and match the turbine shaft speed, maintaining acceptable mechanical stress levels throughout the synchronization process. This dynamic control resolves the contradiction between reducing synchronization time and limiting mechanical stress.
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 allows for efficient operation of accessories without driving the rotatable load, reduces clutch wear, and ensures smooth engagement, enhancing durability and efficiency by synchronizing rotational speeds before engagement, thus addressing the challenges of managing rotational speeds and engaging mechanisms in internal combustion engine systems.
Implementation Method 1
driving a turbine with exhaust gases of the intermittent internal combustion engine to rotate the turbine shaft
Data Source
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AI summary
A method of operating a compoundable engine (10) that includes a turbine (22) having a turbine shaft (26) and an intermittent internal combustion engine (12) having an engine shaft (14). The engine shaft (14) is rotated at a first rotational speed. The turbine (22) is driven by exhaust gases of the intermittent internal combustion engine (12) to rotate the turbine shaft (26) while the engine shaft (14) rotates independently from the turbine shaft (26). A rotatable load (L) is driven with the turbine shaft (26). A rotational speed of the engine shaft (14) is increased from the first rotational speed until the turbine shaft (26) reaches a predetermined rotational speed. After the turbine shaft (26) has reached the predetermined rotational speed, the rotational speed of the engine shaft (14) is adjusted until the turbine shaft (26) and the engine shaft (14) are drivingly engageable with each other, and the turbine shaft (26) with the engine shaft (14) are engaged such that both are in driving engagement with the rotatable load (L).