Control of piston trajectory in a linear generator

Patent metadata

Field	Value
Publication number	US-11339735-B2
Application number	US-202117350224-A
Country	US
Kind code	B2
Filing date	Jun 17, 2021
Priority date	Mar 31, 2016
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

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.

First claim

What is claimed is:

1. A method performed by a programmed computer system for controlling displacement of a free-piston assembly, the method comprising:
a) determining, using a control system, a force to apply to the free-piston assembly based on a current position of the free-piston assembly and a target position without regard to a deviation from a previously determined trajectory;
b) cause the force to be applied to the free-piston assembly for a time interval; and
c) repeating a) and b) until the free-piston assembly reaches at least one of the target position or an apex position.

2. The method of claim 1 , wherein the target position comprises a desired apex position.

3. The method of claim 1 , wherein a) comprises determining the force based at least in part on an estimated pressure in a compression section in contact with the free-piston assembly.

4. The method of claim 1 , further comprising:
d) determining a new target position of the free-piston assembly;
e) determining a new force to apply to the free-piston assembly based on a new current position of the free-piston assembly and the new target position; and
f) causing the new force to be applied to the free-piston assembly for a new time interval.

5. The method of claim 1 , further comprising:
d) determining a new force to apply to the free-piston assembly based on a new current position of the free-piston assembly and the target position; and
e) determining not to apply the new force to the free-piston assembly for a second time interval if the current position is outside of a cut-off position threshold.

6. The method of claim 1 , further comprising determining the target position.

7. The method of claim 1 , wherein determining the force to apply to the free-piston assembly is based on a difference between the current position of the free-piston assembly and the target position.

8. The method of claim 1 , wherein the time interval is a prescribed time interval comprising a fixed frequency.

9. A method performed by a programmed computer system for controlling displacement of a free-piston assembly, the method comprising:
determining, using a control system, a force to apply to the free-piston assembly based on a current position of the free-piston assembly and a target position without regard to a deviation from a previously determined trajectory;
b) cause the force to be applied to the free-piston assembly for a position interval; and
c) repeating a) and b) until the free-piston assembly reaches at least one of the target position or an apex position.

10. The method of claim 9 , wherein the position interval is a particular discrete position interval comprising a fixed distance.

11. A system comprising:
a free-piston assembly configured to traverse a positional path; and
a control system configured to:
a) determine a force to apply to the free-piston assembly based on a current position of the free-piston assembly and a target position without regard to a deviation from a previously determined trajectory;
b) cause the force to be applied to the free-piston assembly for a time interval; and
c) repeat a) and b) until the free-piston assembly reaches at least one of the target position or an apex position.

12. The system of claim 11 , wherein the target position comprises a desired apex position.

13. The system of claim 11 , wherein the control system is further configured to repeat a) and b) by:
repeatedly determining a new force to apply to the free-piston assembly based on a new current position of the free-piston assembly and the target position; and
repeatedly causing the new force to be applied to the free-piston assembly for each respective time interval.

14. The system of claim 11 , wherein the control system is further configured to:
d) determine a new target position of the free-piston assembly;
e) determine a new force to apply to the free-piston assembly based on a new current position of the free-piston assembly and the new target position; and
f) cause the new force to be applied to the free-piston assembly for a second time interval.

15. The system of claim 11 , wherein the control system is further configured to:
d) determine new a force to apply to the free-piston assembly based on a new current position of the free-piston assembly and the target position; and
e) determine not to apply the new force to the free-piston assembly for a second time interval if the current position is outside of a cut-off position threshold.

16. The system of claim 11 , wherein the control system is further configured to determine the target position.

17. The system of claim 11 , wherein the control system is further configured to determine the force to apply to the free-piston assembly based on a difference between the current position of the free-piston assembly and the target position.

18. The system of claim 11 , wherein the time interval is a prescribed time interval comprising a fixed frequency.

19. The system of claim 11 , further comprising a sensor configured to:
sense the current position of the free-piston assembly; and
communicate with the control system.

20. The system of claim 11 , wherein the control system is further configured to determine the force to apply to the free-piston assembly without regard to a time in which the free-piston assembly reaches the target position.

Assignees

• Mainspring Energy Inc

Inventors

• Roelle Matthew
• Gadda Christopher

Classifications

• F02D41/1402

  Adaptive control · CPC title

• F02D29/06

  peculiar to engines driving electric generators · CPC title

• F02B63/04

  for electric generators · CPC title

• F02D35/023

  by determining the cylinder pressure · CPC title

• F02B71/04

  Adaptations of such engines for special use; Combinations of such engines with apparatus driven thereby · CPC title