Hydraulic energy transfer
View Patent ↗A regenerative shock absorber that include a housing and a piston that moves at least partially through the housing when the shock is compressed or extended from a rest position. When the piston moves, hydraulic fluid is pressurized and drives a hydraulic motor. The hydraulic motor, in turn, drives an electric generator that produced electric energy. The electric energy may be provided to a vehicle, among other things. The regenerative shock absorber may also provide ride performance that comparable to or exceeds that of conventional shock absorbers.
1. A shock absorber comprising:
a housing that includes a compression volume and an extension volume;
a piston disposed in the housing and that in a first mode moves through at least a portion of a compression stroke to move hydraulic fluid from the compression volume and that in a second mode moves at least partially through an extension stroke to move hydraulic fluid from the extension volume;
a hydraulic motor including a first port and a second port, the first port in fluid communication with the compression volume and the second port in fluid communication with the extension volume, wherein the hydraulic motor is constructed and arranged to be operated as a hydraulic motor in a first state of operation where the hydraulic motor is driven by the hydraulic fluid flowing between the extension volume and the compression volume through the hydraulic motor, and wherein the hydraulic motor is constructed and arranged to be operated as a pump in a second state of operation where the hydraulic motor drives the hydraulic fluid flowing between the extension volume and the compression volume through the hydraulic motor;
one or more valves in parallel with the hydraulic motor, the one or more valves, when in a bypass mode, provide fluid communication between the compression volume and the extension volume such that at least a portion of the hydraulic fluid bypasses the hydraulic motor during a piston stroke, wherein the stroke comprises at least one of the compression stroke and the extension stroke.
2. The shock absorber of claim 1 , wherein a maximum compression volume is defined when the piston has reached an end of the extension stroke and a maximum extension volume is defined when the piston has reached an end of the compression stroke, wherein the shock absorber includes a reservoir having a reservoir volume equal to or greater than a difference between the maximum extension volume and the maximum compression volume.
3. The shock absorber of claim 2 , wherein the one or more valves are in bypass mode when the piston is in the first mode and wherein the reservoir is in fluid communication with the compression volume during the first mode.
4. The shock absorber of claim 3 , wherein the reservoir is configured to maintain a minimum hydraulic pressure.
5. The shock absorber of claim 4 , wherein the minimum pressure is about 30 psi or greater.
6. The shock absorber of claim 2 , wherein the one or more valves are in bypass mode when the piston is in the second mode and wherein the reservoir is in fluid communication with the extension volume during the second mode.
7. The shock absorber of claim 6 , wherein the reservoir is configured to maintain a minimum hydraulic pressure.
8. The shock absorber of claim 7 , wherein the minimum pressure is about 30 psi or greater.
9. The shock absorber of claim 1 , wherein fluid communication between the first port of the hydraulic motor and the extension volume is valve-free and wherein fluid communication between the second port of the hydraulic motor and the extension volume is valve-free.
10. The shock absorber of claim 1 , wherein the one or more valves comprise one or more check valves.
11. The shock absorber of claim 1 , wherein the one or more valves consists of a check valve.
12. The shock absorber of claim 1 , further comprising: an electric generator coupled to the hydraulic motor.
13. The shock absorber of claim 12 , wherein the electric generator and the hydraulic motor are coupled in a seal-free manner.
14. The shock absorber of claim 12 , further comprising: a controller that controls a load applied to the electric generator.
15. The shock absorber of claim 14 , wherein the controller controls the load according to a look-up table.
16. The shock absorber of claim 14 , wherein the controller controls the load by switching the load between a first resistance element with a first resistance, a vehicle load, and a second resistance element with a second resistance greater than the first resistance.
17. The shock absorber of claim 16 , wherein the controller utilizes pulse width modulation to switch between the first resistance element, the vehicle load, and the second resistance element.
18. The shock absorber of claim 14 , wherein the controller detects a polarity of the electric generator to determine whether the shock absorber is in the first mode or the second mode.
19. The shock absorber of claim 1 , wherein one or more shock absorbers are assembled into a suspension system of a vehicle.
20. The shock absorber of claim 19 , wherein damping of the suspension system is provided primarily by the one or more regenerative shock absorbers.
21. The shock absorber of claim 14 , wherein the controller controls the load according to an equation.
22. The shock absorber of claim 1 , wherein the one or more valves are in the bypass mode when a pressure of the hydraulic fluid is greater than a preset threshold value.
23. The shock absorber of claim 1 , wherein the one or more valves are in the bypass mode when a velocity of the piston is greater than a preset threshold value.
24. The shock absorber of claim 1 , wherein the hydraulic motor is protected from overspinning when the one or more valves are in the bypass mode.
25. The shock absorber of claim 1 , wherein when in the bypass mode, the piston moves with less damping than when in a non-bypass mode.
26. The shock absorber of claim 1 , wherein moving hydraulic fluid through the hydraulic motor provides a damping force.
27. The device of claim 1 , wherein when the hydraulic motor is in the second state of operation it controls the position and/or force of the piston.
28. The device of claim 1 , wherein the bypass is a pressure-relief valve.
29. The shock absorber of claim 1 , wherein the bypass mode of the one or more valves and operation of the hydraulic motor are controlled separately.
30. A shock absorber comprising:
a housing that includes a compression volume and an extension volume;
a hydraulic motor fluidly coupled to the compression volume and the extension volume;
a piston disposed in the housing and that in a first mode moves through at least a portion of a compression stroke to move hydraulic fluid from the compression volume to the extension volume through the hydraulic motor and that in a second mode moves at least partially through an extension stroke to move hydraulic fluid from the extension volume to the compression volume through the hydraulic motor, wherein the hydraulic motor is constructed and arranged to be operated as a hydraulic motor in a first state of operation where the hydraulic motor is driven by the hydraulic fluid flowing between the extension volume and the compression volume through the hydraulic motor, and wherein the hydraulic motor is constructed and arranged to be operated as a pump in a second state of operation where the hydraulic motor drives the hydraulic fluid flowing between the extension volume and the compression volume through the hydraulic motor; and
a bypass in parallel with the hydraulic motor, wherein the bypass is adapted and configured to allow at least a portion of the hydraulic fluid to bypass the hydraulic motor when the bypass is in a bypass mode during a piston stroke, wherein the stroke comprises at least one of the compression stroke and the extension stroke.
31. The shock absorber of claim 30 , wherein the bypass comprises one or more valves.
32. The shock absorber of claim 31 , wherein the one or more valves restrict a flow of fluid through the bypass.
33. The shock absorber of claim 30 , wherein the bypass is in the bypass mode only during one of the compression stroke and the extension stroke.
34. The shock absorber of claim 30 , wherein the bypass is in the bypass mode when a pressure of the hydraulic fluid is greater than a preset threshold value.
35. The shock absorber of claim 30 , wherein the bypass is in the bypass mode when a velocity of the piston is greater than a preset threshold value.
36. The shock absorber of claim 30 , wherein the hydraulic motor is protected from overspinning when the bypass is in the bypass mode.
37. The shock absorber of claim 30 , wherein when in the bypass mode, the piston moves with less damping than in a non-bypass mode.
38. The shock absorber of claim 30 , wherein moving hydraulic fluid through the hydraulic motor provides a damping force.
39. The device of claim 30 , wherein when the hydraulic motor is in the second state of operation it controls the position and/or force of the piston.
40. The device of claim 30 , wherein the bypass is a pressure-relief valve.
41. The shock absorber of claim 30 wherein the bypass mode of the bypass and operation of the hydraulic motor are controlled separately.