Electronic Load Sense Control for Hydraulic Stability

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Solution Overview

Problem

Traditional load sense systems face instability and cost issues due to long hydraulic hoses and rigid control mechanisms, leading to response and stability problems, especially in applications where the pump is far from the control spools.

Innovation Solution

An electronic load sense control system with a micro-processor, pressure transducers, and a proportional pressure relief valve replicates the load sense signal electronically, eliminating the hydraulic load sense line and allowing for variable working margins and torque control through software adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional hydraulic load sense lines are used to connect pump to control spools, then pressure control function is achieved, but system stability deteriorates and response time increases due to long hose lengths

Engineering Contradiction:

Improvesystem stabilityVSAvoidhydraulic hose length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent replaces the traditional mechanical hydraulic load sense line with an electronic sensing and control system. Pressure transducers convert hydraulic pressure signals to electrical signals, which are processed by a microcontroller to generate control signals for proportional valves. This substitution eliminates the long hydraulic hose connection while maintaining the load sense function, thereby improving system stability and reducing response time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electronic intermediaries (pressure transducers, microcontroller, and proportional valves) between the pump and control spools. These intermediaries convert and transmit the load sense signal electronically rather than hydraulically, allowing for faster response and better stability while eliminating the need for long hydraulic hoses.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If fixed working margin is used in traditional load sense systems, then system simplicity is maintained, but adaptability to different operating conditions deteriorates

Engineering Contradiction:

Improvevariable working marginVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic working margin that can be adjusted based on operating conditions. The microcontroller calculates and adjusts the working margin parameter in real-time based on feedback from pressure transducers and system operating state. This allows the system to adapt to different load conditions and optimize performance, transforming the fixed working margin into a dynamic, adjustable parameter.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the working margin from a fixed physical parameter to a variable electronic parameter. Through software control, the working margin can be dynamically adjusted based on system conditions, allowing the same hardware to provide different working margins as needed. This parameter change enables greater adaptability without requiring multiple physical systems.

Inventive Principle:

Principle #35Parameter changes

3Speed

If electronic control system with long hydraulic hoses is used, then pressure control function is achieved, but response speed deteriorates due to signal transmission delays

Engineering Contradiction:

Improvesystem response speedVSAvoidhydraulic hose length

Core Design Contradiction:

SpeedVSLength of moving object

Solution Approach 1:

The patent replaces the mechanical hydraulic signal transmission through long hoses with electronic signal transmission. Pressure transducers convert hydraulic pressure to electrical signals that can be processed and transmitted rapidly by the microcontroller, eliminating the slow response associated with long hydraulic hose transmission and significantly improving system response speed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system stabilizes circuit operation, reduces costs, and provides a full variable working margin, preventing engine stalling by electronically managing pressure and torque within engine capabilities, thus enhancing system performance and efficiency.

Implementation Method 1

sensors that detect pressure on opposite sides of a control valve that control hydraulic flow from a source to a hydraulic actuator. The sensors produce electrical signals indicating pressure.

Methodology Applied

Scientific EffectPressure detection:

Implementation Method 2

a controller produces an output signal which operates a proportional control valve to regulate pressure at a node of a hydraulic circuit

Methodology Applied

Scientific EffectPressure regulation:

Data Source

PatentUS9759212B2Electronic load sense control with electronic variable load sense relief, variable working margin, and electronic torque limiting

Publication Date: 2017.09.12 DANFOSS POWER SOLUTIONS INC

AI summary

An electrical pressure control load sense system having a pump connected inline to an operator control spool valve and a compensation circuit. The system also has a plurality of sensors, at least one pressure transducer, a micro-processor, a fixed orifice, a proportional pressure relief valve, and a swashplate angle sensor.