Free-Piston Engine Trajectory Control via Dynamic Recalculation
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Solution Overview
Problem
Existing free-piston combustion engines rely on open-form solutions for controlling piston movement based on predetermined trajectories, which do not account for changing engine conditions, leading to inefficiencies and potential misalignment with desired performance.
Innovation Solution
A processing subsystem in the free-piston engine calculates a position-force trajectory for one or more piston assemblies based on their current position and desired engine performance, without regard to deviations from previous trajectories, allowing for real-time adjustments to changing engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If open-form control solutions based on predetermined trajectories are used, then the control system is simple to implement, but the system cannot adapt to changing engine conditions
Solution Approach 1:
The patent implements dynamic trajectory recalculation based on current piston position and changing engine conditions. Instead of following a fixed predetermined trajectory, the control system continuously updates the trajectory in real-time, allowing the piston movement path to adapt dynamically to varying operating conditions while maintaining manageable system complexity through efficient calculation methods
Solution Approach 2:
The control system incorporates feedback mechanisms that monitor current piston position and engine conditions, then use this information to recalculate and adjust the trajectory. This closed-loop feedback enables the system to adapt to changing conditions by comparing actual position with desired position and modifying subsequent movement commands accordingly
2Productivity
If predetermined trajectories are used for piston control, then the control strategy is straightforward, but efficiency decreases due to inability to account for changing conditions
Solution Approach 1:
The system dynamically recalculates trajectories based on current engine conditions and piston position, enabling the control strategy to adapt to changing loads, temperatures, and operational states. This dynamic approach improves engine efficiency by optimizing piston movement for current conditions rather than following a static predetermined path
Solution Approach 2:
The control system changes key trajectory parameters such as position, velocity, and acceleration targets based on current engine operating conditions. By adjusting these parameters in real-time according to actual piston position and engine state, the system maintains high efficiency across varying operational scenarios
3Speed
If deviation compensation from original trajectory is implemented, then the original trajectory can be maintained, but the system responds slowly to rapid condition changes
Solution Approach 1:
The system implements dynamic trajectory recalculation that responds immediately to changes in piston position and engine conditions. Rather than slowly compensating for deviations from a fixed trajectory, the system rapidly generates new trajectory segments adapted to current conditions, achieving both fast response and maintained accuracy
Solution Approach 2:
The control system proactively recalculates trajectories based on predicted future conditions and current state, rather than reactively compensating for past deviations. This preliminary action allows the system to anticipate and prepare for upcoming position requirements while adapting to changing conditions, improving both response speed and trajectory accuracy
Data Source
AI summary
Various embodiments of the present disclosure are directed towards free-piston combustion engines. As described herein, a method and system are provided for displacing a free-piston assembly to achieve a desired engine performance by repeatedly determining position-force trajectories over the course of a propagation path and effecting the displacement of the free-piston assembly based, at least in part, on the position-force trajectory. In a dual-piston assembly free-piston engine, synchronization of the two piston assemblies is provided.