Methods and systems for managing a clearance gap in a piston engine

Patent metadata

Field	Value
Publication number	US-RE49259-E
Application number	US-202016912538-A
Country	US
Kind code	E1
Filing date	Nov 30, 2020
Priority date	Dec 29, 2011
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

A piston engine may include a clearance gap between a piston assembly and a cylinder. The piston may be configured to translate in a bore of the cylinder. The clearance gap between the piston assembly and the bore may be actively or passively controlled. A control system may provide one or more adjustments based on, for example, a detected temperature, pressure, flow rate, work metric, and/or other indicator. The adjustments may include, for example, adjusting a cylinder liner, adjusting a flow through a bearing element, adjusting a coolant flow, adjusting a heat pipe property, and/or other adjustments. One or more auxiliary systems may be used to provide the adjustments.

First claim

What is claimed is:

1. A method of controlling a clearance gap between a piston assembly and a cylinder of a free-piston engine, the method comprising:
detecting at least one indicator of the clearance gap;
determining a control response based at least in part on the indicator;
generating a control signal based at least in part on the control response; and
causing the clearance gap to be adjusted based at least in part on the control signal, wherein:
the piston assembly comprises at least one feature or component that interacts with blow-by gas from a compression section of the free-piston engine to aid in centering the piston assembly, wherein the at least one feature or component is selected from the group consisting of a step, a slotted pocket, a labyrinth, and any combination thereof.

2. The method of claim 1 , wherein the at least one indicator comprises a temperature.

3. The method of claim 1 , wherein the at least one indicator comprises a thickness of the clearance gap.

4. The method of claim 1 , wherein the at least one indicator comprises a pressure.

5. The method of claim 1 , wherein the at least one indicator comprises a gas flow rate.

6. The method of claim 1 , wherein the at least one indicator comprises a work interaction of the free-piston engine.

7. The method of claim 1 , wherein the at least one indicator comprises a velocity.

8. The method of claim 1 , wherein the at least one indicator comprises an acceleration.

9. The method of claim 1 , wherein causing the clearance gap to be adjusted comprises causing a pressure to be adjusted to a cylinder liner positioned coaxial in the cylinder.

10. The method of claim 1 , wherein causing the clearance gap to be adjusted comprises causing a flow of a bearing fluid through a bearing element of the free-piston engine to be adjusted.

11. The method of claim 1 , wherein causing the clearance gap to be adjusted comprises providing a coolant to at least one of the piston assembly and the cylinder to control a temperature of the free-piston engine.

12. The method of claim 1 , wherein causing the clearance gap to be adjusted comprises causing a property of a heat pipe of the free-piston engine to be adjusted.

13. The method of claim 1 , wherein causing the clearance gap to be adjusted comprises causing a force applied to a piston assembly of the free-piston engine to be adjusted.

14. The method of claim 1 , wherein causing the clearance gap to be adjusted comprises causing a pressure of a gas flow to the inside of the cylinder to be adjusted.

15. A system configured to control a clearance gap between a piston assembly and a cylinder of a free-piston engine, the system comprising:
at least one sensor configured to detect at least one indicator of the clearance gap;
processing equipment configured to determine a control response based at least in part on the at least one indicator; and
a control interface configured to provide a control signal based at least in part on the control response, wherein:
the piston assembly comprises at least one feature or component that interacts with blow-by gas from a compression section of the free-piston engine to aid in centering the piston assembly, wherein the at least one feature or component is selected from the group consisting of a step, a slotted pocket, a labyrinth, and any combination thereof.

16. The system of claim 15 , wherein the at least one sensor is configured to detect a temperature.

17. The system of claim 15 , wherein the at least one sensor is configured to detect a thickness of the clearance gap.

18. The system of claim 15 , wherein the at least one sensor is configured to detect a pressure.

19. The system of claim 15 , wherein the at least one sensor is configured to detect a fluid flow rate.

20. The system of claim 15 , wherein the at least one sensor is configured to detect a work output of the free-piston engine or work input to the free-piston engine.

21. The system of claim 15 , wherein the at least one sensor is configured to detect a velocity.

22. The system of claim 15 , further comprising at least one auxiliary system configured to adjust the clearance gap based at least in part on the control signal.

23. The system of claim 22 , wherein the at least one auxiliary system is configured to adjust the clearance gap by adjusting a pressure to the outside of a cylinder liner positioned coaxial in the cylinder to reduce or increase the clearance gap in response to the control signal.

24. The system of claim 22 , wherein the at least one auxiliary system is configured to adjust the clearance gap by increasing or decreasing a gas flow through a bearing element of the free-piston engine in response to the control signal.

25. The system of claim 22 , wherein the at least one auxiliary system is configured to adjust the clearance gap by providing a coolant to at least one of the piston assembly and the cylinder to control a temperature of the free-piston engine in response to the control signal.

26. The system of claim 22 , wherein the at least one auxiliary system is configured to adjust the clearance gap by adjusting a property of a heat pipe of the free-piston engine in response to the control signal.

27. The system of claim 22 , wherein the at least one auxiliary system is configured to adjust a force applied to a piston assembly of the free-piston engine in response to the control signal.

28. The system of claim 22 , wherein the at least one auxiliary system is configured to adjust a pressure of a gas flow to the inside of the cylinder in response to the control signal.

29. A method of controlling a clearance gap between a piston assembly and a cylinder of a free-piston engine, the method comprising:
causing the clearance gap to be adjusted based at least in part on a control signal, wherein: the piston assembly comprises at least one feature or component that interacts with blow-by gas from a compression section of the free-piston engine to aid in centering the piston assembly, wherein the at least one feature or component is selected from the group consisting of a step, a slotted pocket, a labyrinth, and any combination thereof.

30. The method of claim 29, further comprising:
generating a control signal based at least in part on a control response corresponding to at least one indicator of the clear gap, wherein the at least one indicator comprises a temperature.

31. The method of claim 29, further comprising:
generating a control signal based at least in part on a control response corresponding to at least one indicator of the clear gap, wherein the at least one indicator comprises a thickness of the clearance gap.

32. The method of claim 29, further comprising:
generating a control signal based at least in part on a control response corresponding to at least one indicator of the clear gap, wherein the at least one indicator comprises a pressure.

33. The method of claim 29, further comprising:
generating a control signal based at least in part on a control response corresponding to at least one indicator of the clear gap, wherein the at least one indicator comprises a gas flow rate.

34. The method of claim 29, further comprising:
generating a control signal based at least in part on a control response correspo

Assignees

• Mainspring Energy Inc

Inventors

• Lawler John
• Svrcek Matt

Classifications

• F02B71/04

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

• F01B11/02

  Equalising or cushioning devices · CPC title

• F02F1/18 Primary

  Other cylinders · CPC title

• F16J10/02

  Cylinders designed to receive moving pistons or plungers · CPC title

• F16J1/09

  with means for guiding fluids (F16J1/08 takes precedence) · CPC title