Accumulator pre-charge monitoring using position sensor

Patent metadata

Field	Value
Publication number	US-11788563-B2
Application number	US-202017127277-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Apr 24, 2020
Publication date	Oct 17, 2023
Grant date	Oct 17, 2023

Abstract

Systems and methods for determining a pre-charge gas pressure in a gas-charged hydraulic accumulator are disclosed. For example, systems and methods for determining pre-charged gas pressure of a gas-charged hydraulic accumulator included as part of a vehicle are disclosed. Further, the present disclosure provides for determining a pre-charge gas pressure of a gas-charged hydraulic accumulator using a position sensor. The accumulator may form part of a hydraulic system used to move one part of the vehicle relative to another.

First claim

What is claimed is:

1. A method for detecting a pressure condition of a gas-charged hydraulic accumulator, the method comprising:
lifting a first portion of a vehicle relative to a second portion of the vehicle to a selected height with hydraulic fluid at a pressure in excess of a first pressure;
releasing the pressure in excess of the first pressure to cause the first portion of the vehicle to fall relative to the second portion of the vehicle;
establishing the hydraulic fluid at the first pressure when the first portion has fallen by a selected amount;
compressing a gas within a gas-charged hydraulic accumulator with the hydraulic fluid at the first pressure;
causing the first portion of the vehicle to rebound relative to the second portion of the vehicle in response to compression of the gas within the gas-charged hydraulic accumulator; and
determining a pre-charge gas pressure in the gas-charged hydraulic accumulator in response to the rebound of the first portion of the vehicle relative to the second portion of the vehicle, the pre-charge gas pressure being a gas pressure within the gas-charged hydraulic accumulator in the absence of hydraulic pressure.

2. The method of claim 1 , wherein determining the pre-charge gas pressure in the gas-charged hydraulic accumulator in response to the rebound of the first portion of the vehicle relative to the second portion of the vehicle comprises determining a distance that the first portion of the vehicle rebounds in response to the hydraulic pressure established at the first pressure.

3. The method of claim 2 , wherein the distance that the first portion of the vehicle rebounds relative to the second portion of the vehicle is a change in length of an actuator coupled between the first portion of the vehicle and the second portion of the vehicle.

4. The method of claim 1 , wherein determining the pre-charge gas pressure in the gas-charged hydraulic accumulator in response to the rebound of the first portion of the vehicle relative to the second portion of the vehicle comprises determining the pre-charge gas pressure according to the relationship

P
0

(

x
,

a

)

=

(

x
a

)

·

[

n
·

(

F

F
⁢
1

)

2

V
o

·
m

]

,

where P 0 is the pre-charge gas pressure within the gas-charged hydraulic accumulator; x is the distance that the first portion of the vehicle rebounds relative to the second portion of the vehicle; a is the acceleration of the first portion of the vehicle as the first portion of the vehicle falls relative to the second portion of the vehicle; n is a polytropic exponent of the gas contained in the gas-charged hydraulic accumulator; F F1 is the static suspension force used to maintain the first portion in a vertically stationary position; V 0 is the internal volume of the gas-charged hydraulic accumulator; and m is the mass of the first portion of the vehicle or part of the first portion of the vehicle supported by F F1 .

5. The method of claim 1 , wherein lifting the first portion of the vehicle relative to the second portion of the vehicle to a selected height with hydraulic fluid at a pressure in excess of a first pressure comprises pivoting the first portion of the vehicle about a pivoting axis coupled to the second portion of the vehicle.

6. The method of claim 1 , further comprising:
comparing the determined pre-charge gas pressure to a selected gas pressure; and
altering a pressure of the gas within the gas-charged hydraulic accumulator when the determined pre-charge gas pressure varies by a selected amount from the selected gas pressure.

7. A method for detecting a pressure condition in a gas-charged hydraulic accumulator for a vehicle, the method comprising:
lifting, with a first hydraulic pressure greater than a selected hydraulic pressure, a first portion of the vehicle relative to a second portion of the vehicle to a selected height, the first portion of the vehicle coupled to the second portion of the vehicle;
lowering, with a second hydraulic pressure greater than the selected hydraulic pressure, the first portion of the vehicle relative to the second portion of the vehicle;
stopping the lowering of a first portion of the vehicle relative to the second portion when the first portion has been lowered by a selected amount;
rebounding the first portion of the vehicle relative to the second portion of the vehicle with a gas-charged hydraulic actuator;
sensing an amount of rebound of the first portion of the vehicle relative to the second portion; and
determining a pre-charge gas pressure within the gas-charged hydraulic accumulator using the amount of rebound of the first portion of the vehicle relative to the second portion of the vehicle, the pre-charge gas pressure being a gas pressure within the gas-charged hydraulic accumulator in the absence of applied hydraulic pressure.

8. The method of claim 7 , wherein lifting, with a first hydraulic pressure greater than a selected hydraulic pressure, the first portion of the vehicle relative to a second portion of the vehicle to as selected height comprises applying the first hydraulic pressure to a first end of a hydraulic actuator; and
wherein lowering, with the second hydraulic pressure greater than the selected hydraulic pressure, the first portion of the vehicle relative to the second portion of the vehicle comprises applying the second hydraulic pressure to a second end of the hydraulic actuator opposite the first end.

9. The method of claim 8 , wherein the selected height is a maximum stroke of the hydraulic actuator.

10. The method of claim 7 , wherein determining the pre-charge gas pressure within the gas-charged hydraulic accumulator using the amount of rebound of the first portion of the vehicle relative to the second portion of the vehicle comprises determining the pre-charge gas pressure according to the relationship

P
0

(

x
,

a

)

Assignees

• Deere & Co

Inventors

• Reiners Alexander C
• Dighton John A
• Johnson Peter A

Classifications

• F15B19/00 Primary

  Testing; {Calibrating; Fault detection or monitoring; Simulation or modelling of} fluid-pressure systems or apparatus not otherwise provided for · CPC title

• E02F9/2257

  Vehicle levelling or suspension systems (suspensions for vehicles in general B60G) · CPC title

• F15B1/08

  using a gas cushion; Gas charging devices; Indicators or floats therefor · CPC title

• F15B2211/857

  Monitoring of fluid pressure systems · CPC title

• E02F9/2217 Primary

  with energy recovery arrangements, e.g. using accumulators, flywheels · CPC title