Series hydraulic hybrid system for a vehicle and method of operating a series hydraulic hybrid system for a vehicle

Patent metadata

Field	Value
Publication number	US-11255429-B2
Application number	US-201716308617-A
Country	US
Kind code	B2
Filing date	Jun 12, 2017
Priority date	Jun 13, 2016
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

A series hydraulic hybrid system for a vehicle may have: a hydraulic circuit with a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit, a hydraulic actuator, and a hydraulic accumulator assembly. The hydraulic accumulator assembly is selectively in fluid communication with the hydraulic circuit via at least one controllable circuit valve. The hydraulic accumulator assembly is selectively in fluid communication with the hydraulic actuator via at least one controllable actuator valve, such that the hydraulic accumulator assembly is configured to be selectively fluidly connected with and to be selectively fluidly disconnected from the hydraulic actuator via the at least one actuator valve independently of a control position of the at least one circuit valve. A method of operating the system is also described.

First claim

The invention claimed is:

1. A hydraulic hybrid system for a vehicle, comprising:
a first hydraulic circuit comprising:
a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit, the first displacement unit connected to an engine;

a hydraulic actuator;
a hydraulic accumulator assembly selectively in fluid communication with the first hydraulic circuit via at least one circuit valve, and the at least one circuit valve controllable to allow fluid flow from the first hydraulic displacement unit to the hydraulic accumulator assembly and from the hydraulic accumulator assembly to the second displacement unit;
at least one actuator valve selectively connecting the hydraulic accumulator assembly with the hydraulic actuator to allow fluid flow from the hydraulic accumulator assembly to the hydraulic actuator, and the at least one actuator valve and the at least one circuit valve operating independently of one another;
a working pump fluidly connected with the hydraulic actuator for selectively pressurizing the hydraulic actuator; and
a control unit configured to control the at least one circuit valve, and configured to control the at least one actuator valve and the working pump such that an actuator pressure acting on the hydraulic actuator remains constant when the hydraulic accumulator assembly is fluidly connected with the hydraulic actuator and/or fluidly disconnected from the hydraulic actuator.

2. The hydraulic hybrid system of claim 1 , wherein the at least one circuit valve and the at least one actuator valve are controllable in such a way that the hydraulic accumulator assembly is:
a) selectively fluidly connected with the hydraulic actuator and fluidly disconnected from the first hydraulic circuit,
b) selectively fluidly connected with the first hydraulic circuit and fluidly disconnected from the hydraulic actuator, and
c) selectively fluidly disconnected from the first hydraulic circuit and fluidly disconnected from the hydraulic actuator.

3. The hydraulic hybrid system of claim 1 , further comprising a vehicle output and the second hydraulic displacement unit is drivingly engaged or selectively drivingly engaged with the vehicle output.

4. The hydraulic hybrid system of claim 1 , wherein the hydraulic accumulator assembly comprises a high pressure hydraulic accumulator and a low pressure hydraulic accumulator,
wherein the at least one circuit valve is configured to selectively fluidly connect the high pressure hydraulic accumulator with the first hydraulic circuit and to selectively fluidly connect the low pressure hydraulic accumulator with the first hydraulic circuit to drive fluid from the low pressure accumulator to the high pressure accumulator and to allow fluid flow from the high pressure accumulator, through the second displacement unit, to the low pressure accumulator, and/or
wherein the at least one actuator valve is configured to selectively fluidly connect the high pressure hydraulic accumulator with the hydraulic actuator and to selectively fluidly connect the low pressure hydraulic accumulator with the hydraulic actuator to allow fluid flow from the high pressure accumulator to the hydraulic actuator and from the hydraulic actuator to the low pressure accumulator.

5. The hydraulic hybrid system of claim 4 ,
wherein the first hydraulic circuit comprises a first main fluid line fluidly connecting or selectively fluidly connecting a first fluid port of the first hydraulic displacement unit with a first fluid port of the second hydraulic displacement unit,
wherein the first hydraulic circuit comprises a second main fluid line fluidly connecting or selectively fluidly connecting a second fluid port of the first hydraulic displacement unit with a second fluid port of the second hydraulic displacement unit, and
wherein the at least one circuit valve is configured to selectively:
fluidly disconnect the hydraulic accumulators from the first hydraulic circuit;
fluidly connect the high pressure hydraulic accumulator with the first main fluid line and fluidly connect the low pressure hydraulic accumulator with the second main fluid line while fluidly disconnecting the high pressure hydraulic accumulator from the second main fluid line and while fluidly disconnecting the low pressure hydraulic accumulator from the first main fluid line to allow fluid flow from the high pressure accumulator through the second displacement unit to the low pressure accumulator; and
fluidly connect the low pressure hydraulic accumulator with the first main fluid line and fluidly connect the high pressure hydraulic accumulator with the second main fluid line while fluidly disconnecting the low pressure hydraulic accumulator from the second main fluid line and while fluidly disconnecting the high pressure hydraulic accumulator from the first main fluid line.

6. The hydraulic hybrid system of claim 4 ,
wherein the hydraulic actuator comprises a first fluid port and a second fluid port,
wherein the at least one actuator valve is configured to selectively fluidly connect the high pressure hydraulic accumulator with the first fluid port of the hydraulic actuator and to selectively fluidly connect the low pressure hydraulic accumulator with the second fluid port of the hydraulic actuator such that the actuator receives fluid from the high pressure accumulator and sends fluid to the low pressure accumulator.

7. The hydraulic hybrid system of claim 1 , further comprising at least one accumulator pressure sensor configured to measure an accumulator pressure in the hydraulic accumulator assembly.

8. The hydraulic hybrid system of claim 1 , further comprising a steering arrangement for steering a vehicle, wherein the hydraulic actuator is drivingly engaged with the steering arrangement for selectively actuating the steering arrangement, and
the first displacement unit is connected to an engine, and
the second displacement unit is connected to a vehicle drive and the second displacement unit charges a low pressure accumulator of the hydraulic accumulator assembly during regenerative braking.

9. The hydraulic hybrid system of claim 1 , wherein the working pump fluidly connected or selectively fluidly connected with the hydraulic actuator for selectively pressurizing the hydraulic actuator, wherein a check valve is configured to allow a flow of fluid from the working pump to the hydraulic actuator and to prevent a flow of fluid from the hydraulic accumulator assembly and from the hydraulic actuator to the working pump.

10. The hydraulic hybrid system of claim 1 ,
wherein the control unit is configured to compare an accumulator pressure with a predetermined minimum actuator pressure, and
wherein the control unit is configured to control the at least one actuator valve to fluidly connect the hydraulic accumulator assembly with the hydraulic actuator if the accumulator pressure is above the minimum actuator pressure, and/or
wherein the control unit is configured to control the at least one actuator valve to fluidly disconnect the hydraulic accumulator assembly from the hydraulic actuator if the accumulator pressure falls below the minimum actuator pressure.

11. The hydraulic hybrid system of claim 10 ,
wherein the working pump has a variable hydraulic displacement and wherein the control unit is configured to reduce the hydraulic displacement of the working pump when the hydraulic accumulator assembly is fluidly connected with the hydraulic actuator.

12. The hydraulic hybrid system of claim 1 , further comprising an actuator pressure sensor for measuring the actuator pressure, wherein the control unit is configured to control the at least

Assignees

• Dana Italia Srl

Inventors

• Giorgio Bort Carlos Maximiliano
• Moser Davide
• Ornella Giulio

Classifications

• B62D5/06

  fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle · CPC title

• B60K6/12

  by means of a chargeable fluidic accumulator · CPC title

• F16H61/4096

  with pressure accumulators · CPC title

• F16H61/4078 Primary

  Fluid exchange between hydrostatic circuits and external sources or consumers · CPC title

• F15B2211/88

  Control measures for saving energy · CPC title