Free-Piston Trajectory Control via Dynamic Position-Force Computation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing free-piston combustion engines face challenges in controlling piston trajectory, as they often rely on open-form solutions that do not account for changing engine conditions, leading to deviations from desired trajectories and inefficiencies.
Innovation Solution
A processing sub-system computes a position-force trajectory for piston assemblies based on current position and desired engine performance, applying forces to achieve desired positions, velocities, and accelerations, while accounting for changing operating states without relying on previous trajectory deviations, using sensors to measure and estimate parameters like pressure and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open-form control solutions are used based on previously determined trajectories, then the control system is simple to implement, but the piston trajectory deviates from desired positions when engine conditions change
Solution Approach 1:
The control system dynamically determines piston trajectory in real-time based on current engine conditions rather than following a pre-determined fixed trajectory. The system continuously updates the desired piston position, velocity, and acceleration based on measured crankshaft position and engine state, allowing the trajectory to adapt dynamically to changing conditions while maintaining control simplicity through a unified control law.
2Reliability
If trajectory control compensates for deviations from previously determined trajectories, then the control system can handle some variations, but it still relies on open-form solutions that do not account for real-time changing engine conditions
Solution Approach 1:
The control system uses feedback from measured crankshaft position and engine conditions to continuously determine the desired piston trajectory in real-time. Rather than measuring deviation from a pre-determined trajectory and compensating, the system directly calculates the desired trajectory based on current engine state, providing both accurate trajectory tracking and adaptability to changing conditions through continuous feedback-based recalculation.
3Measurement precision
If expensive sensors are used to precisely measure engine parameters, then measurement precision improves, but system cost and complexity increase
Solution Approach 1:
The control system uses readily available measurements from the engine's existing crankshaft position sensor to derive all necessary trajectory control information. By calculating desired piston position, velocity, and acceleration from crankshaft position data alone, the system eliminates the need for additional expensive sensors while maintaining sufficient measurement precision for effective control.
Data Source
Figure 1
Figure 2~3
Figure 4
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.