Dual Hydraulic Circuit Work Implement Control

Solution Overview

Problem

Hydraulic control systems with smaller cross-sectional area control valves are less power efficient and slower to respond when handling resistive and overrunning loads, compromising the control and productivity of work implements in machines.

Innovation Solution

A control system comprising a first and second hydraulic circuit, with a hydraulic cylinder assembly and a controller that generates a connection to tank signal based on the pressure difference between the head end and rod end, allowing fluid to be directed from either end to a tank, optimizing fluid flow and pressure management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If smaller cross-sectional area control valves are used, then fine control of work implement movements is improved, but power efficiency and response speed deteriorate when handling resistive loads

Engineering Contradiction:

Improvefine control precisionVSAvoidpower efficiency

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between two hydraulic circuits based on operating conditions. The first circuit with smaller cross-sectional area valves is used during normal operations for fine control, while the second circuit with larger cross-sectional area valves is activated during resistive loads for improved power efficiency and response speed. This dynamic reconfiguration resolves the contradiction by adapting valve characteristics to operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the effective valve cross-sectional area parameter based on load conditions. By switching between two hydraulic circuits with different valve sizes, the system adjusts the flow capacity parameter to match operational demands, achieving both fine control during normal operations and high power efficiency during resistive loads.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If smaller cross-sectional area control valves are used, then fine control of work implement movements is improved, but response speed deteriorates when handling resistive loads

Engineering Contradiction:

Improvefine control precisionVSAvoidresponse speed

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The system dynamically switches between two hydraulic circuits based on operating conditions. The first circuit with smaller cross-sectional area valves is used during normal operations for fine control, while the second circuit with larger cross-sectional area valves is activated during resistive loads for improved power efficiency and response speed. This dynamic reconfiguration resolves the contradiction by adapting valve characteristics to operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the effective valve cross-sectional area parameter based on load conditions. By switching between two hydraulic circuits with different valve sizes, the system adjusts the flow capacity parameter to match operational demands, achieving both fine control during normal operations and high power efficiency during resistive loads.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If larger cross-sectional area control valves are used, then power efficiency and response speed are improved, but fine control capability deteriorates

Engineering Contradiction:

Improvepower efficiencyVSAvoidfine control precision

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The system dynamically switches between two hydraulic circuits based on operating conditions. The first circuit with smaller cross-sectional area valves is used during normal operations for fine control, while the second circuit with larger cross-sectional area valves is activated during resistive loads for improved power efficiency and response speed. This dynamic reconfiguration resolves the contradiction by adapting valve characteristics to operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the effective valve cross-sectional area parameter based on load conditions. By switching between two hydraulic circuits with different valve sizes, the system adjusts the flow capacity parameter to match operational demands, achieving both fine control during normal operations and high power efficiency during resistive loads.

Inventive Principle:

Principle #35Parameter changes

4Speed

If larger cross-sectional area control valves are used, then response speed is improved, but fine control capability deteriorates

Engineering Contradiction:

Improveresponse speedVSAvoidfine control precision

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The system dynamically switches between two hydraulic circuits based on operating conditions. The first circuit with smaller cross-sectional area valves is used during normal operations for fine control, while the second circuit with larger cross-sectional area valves is activated during resistive loads for improved power efficiency and response speed. This dynamic reconfiguration resolves the contradiction by adapting valve characteristics to operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the effective valve cross-sectional area parameter based on load conditions. By switching between two hydraulic circuits with different valve sizes, the system adjusts the flow capacity parameter to match operational demands, achieving both fine control during normal operations and high power efficiency during resistive loads.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enhances the efficiency and responsiveness of work implement control systems by managing fluid flow effectively, improving control and productivity during resistive and overrunning loads, while maintaining fine movement precision.

Implementation Method 1

generating a connection to tank control signal as a function of the work implement function, and the difference between the fluid pressure on the rod end and the fluid pressure on the head end

Methodology Applied

Scientific EffectFluid pressure differential: Pressure Gradient

Data Source

PatentUS9169620B2Work implement control system

Publication Date: 2015.10.27 CATERPILLAR INC

AI summary

A control system for a work implement on a machine is disclosed including a first hydraulic circuit, a second hydraulic circuit, and a controller. The first hydraulic circuit includes a hydraulic cylinder assembly, a pressurized fluid source, and a fluid tank. The hydraulic cylinder assembly includes a head end, a rod end, a cylinder, and a rod. The pressurized fluid source and the fluid tank are selectively connected to the head end or the rod end. The second hydraulic circuit includes a valve configured to receive a connection to tank signal and selectively connect the head end or the rod end to the fluid tank. The controller is configured to generate the connection to tank signal.