Electro-Hydraulic Actuation Circuit for Low-Energy Shaking Control

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Solution Overview

Problem

Electrified agricultural vehicles face inefficiencies in electricity consumption due to the continuous operation of electric motors at minimum rotation speeds, which is not necessary for hydraulic pump operation, leading to potential energy wastage and reduced battery life.

Innovation Solution

A hydraulic circuit with a fixed displacement pump and an open center control directional electro-valve controlled by a joystick, featuring a selector for shaking mode, a module to measure joystick signal frequency and amplitude, and a command module to optimize motor and valve signals for efficient oil flow during shaking operations, reducing unnecessary energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electric motor is operated continuously at minimum rotation speed to power the hydraulic pump, then the hydraulic system is always ready for operation, but electricity consumption increases unnecessarily

Engineering Contradiction:
Improvehydraulic system readinessVSAvoidelectricity consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by enabling the electric motor to operate intermittently rather than continuously. The motor starts only when hydraulic actuation is detected via joystick input, and stops when not needed. This is achieved through a control unit that monitors joystick position and activates the motor only during actual operation, eliminating continuous minimum-speed operation while maintaining system readiness when needed.

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If the electric motor is stopped to save electricity, then energy consumption is reduced, but the hydraulic system is not immediately ready for operation

Engineering Contradiction:
Improveelectricity consumptionVSAvoidsystem responsiveness
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies feedback through a control unit that continuously monitors the joystick position and hydraulic system state. When the joystick is moved from neutral position, the control unit detects this input and immediately activates the electric motor and hydraulic pump. This feedback mechanism ensures the system responds instantly to user commands while allowing the motor to remain stopped during idle periods, balancing energy savings with operational responsiveness.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If a variable displacement pump is used to optimize flow control, then energy efficiency improves, but device complexity and cost increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidpump system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements dynamics by using a simple on/off control strategy for a fixed displacement pump rather than a complex variable displacement pump. The motor and pump operate at full capacity only when needed, and stop completely when not needed. This dynamic start-stop operation with a simple pump achieves energy efficiency comparable to variable displacement systems while maintaining much lower complexity and cost.

Inventive Principle:
Principle #15Dynamics

4Reliability

If oil flow is discharged to the tank during idle periods, then the hydraulic system is reset for next operation, but energy is wasted through continuous circulation

Engineering Contradiction:
Improvesystem reset readinessVSAvoidenergy dissipation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the unnecessary continuous oil circulation function from the system. Instead of maintaining continuous flow through the hydraulic circuit and discharging to tank during idle periods, the system stops the pump entirely when not in use. This eliminates the energy waste associated with continuous circulation while maintaining system readiness, as the pump can immediately resume operation when hydraulic actuation is detected.

Inventive Principle:
Principle #2Taking out (Extraction)

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 allows for precise control of oil flow, minimizing energy wastage by only providing the necessary flow for shaking operations, thus extending the vehicle's battery life and reducing the likelihood of breakdowns.

Implementation Method 1

a fixed displacement hydraulic pump and an open center control directional electro-valve

Methodology Applied
Scientific EffectHydraulic pump: Pump

Implementation Method 2

an open center control directional electro-valve controlled by the user by means of a joystick

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Implementation Method 3

hydraulic actuator enslaved to the movement of a hydraulic work member

Methodology Applied
Scientific EffectHydraulic actuation: Hydraulic Press

Data Source

PatentEP4124760B1Electro-hydraulic actuation circuit of a hydraulic actuator for an electrified work vehicle and corresponding method
Publication Date: 2024.06.12 CNH IND ITALIA SPA
  • EP4124760B1 patent drawingFigure 1
  • EP4124760B1 patent drawingFigure 2~3
  • EP4124760B1 patent drawingFigure 4

AI summary

An electro-hydraulic circuit includes a fixed displacement hydraulic pump (P) and an electric motor (M) arranged to drive the hydraulic pump in rotation, a recovery tank (T), a hydraulic actuator (BOOM, BUCKET), an open center proportional directional electro-valve (V1, V2) comprising a release condition in which it isolates the hydraulic actuator by hydraulically connecting the hydraulic pump with the recovery tank, a selector (SEL) to select a mode of execution of a repetitive operation of the actuator, a processing unit (STK) to receive the signals of the selector and an input device (Joystick) operated by a user and generate control signals for the electro-valve (V2) and for the engine (M), wherein a number of revolutions of the electric motor (M) is determined based on the selector and an amplitude of oscillation of the input device as it is manipulated by the user to perform the repetitive operation, and a frequency of the command signal for the electro-valve (V2) it is determined on the basis of a frequency acquired through the input device.