Hydraulic Leak Detection With Delayed Shutdown for Mowing Circuits

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Solution Overview

Problem

Existing hydraulic leak detection systems in grass mowing machines require operators to disable hydraulic circuits or ignore leak warnings, risking turf damage and inefficiency.

Innovation Solution

A hydraulic leak detection system with a vehicle controller, solenoid valve, and temperature sensor that compensates for fluid expansion/contraction, allowing continued operation until cutting units are raised, then shuts down circuits to prevent further leaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the operator is required to turn off hydraulic circuits immediately when a leak is detected, then hydraulic fluid loss is reduced, but productivity decreases and turf damage risk increases

Engineering Contradiction:
Improvehydraulic fluid lossVSAvoidmowing efficiency
Core Design Contradiction:
Loss of substanceVSProductivity

Solution Approach 1:

The system performs preliminary detection and warning before requiring circuit shutdown. The leak detection switch monitors hydraulic fluid levels continuously and provides advance warning to the operator, allowing the operator to complete the current mowing pass before shutting down circuits, thus preventing immediate productivity loss while still addressing the fluid leak issue

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the response based on operational context. Rather than requiring immediate shutdown upon detection, the system allows continued operation until the cutting units are raised, adapting the shutdown timing to the operational phase to minimize turf damage and productivity impact

Inventive Principle:
Principle #15Dynamics

2Object-generated harmful factors

If the operator is required to disable the hydraulic mow circuit during operation, then hydraulic fluid leak onto turf is prevented, but the risk of turf damage increases due to sudden circuit shutdown

Engineering Contradiction:
Improvehydraulic fluid leak onto turfVSAvoidturf damage from sudden shutdown
Core Design Contradiction:
Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The system raises the cutting units as a preliminary action before shutting down the hydraulic mow circuit. This sequence ensures that the cutting units are no longer in contact with the turf when hydraulic fluid leakage occurs during circuit shutdown, eliminating the risk of turf damage from sudden shutdown while still preventing fluid contamination

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system takes preliminary anti-action by blocking the lift and lower circuit from lowering the cutting units after they are raised. This prevents the cutting units from accidentally returning to the turf position during or after circuit shutdown, providing an additional layer of protection against turf damage

Inventive Principle:
Principle #9Preliminary anti-action

3Productivity

If operators are allowed to ignore leak warnings and continue mowing, then productivity is maintained, but hydraulic fluid continues to leak onto the turf

Engineering Contradiction:
Improvemowing efficiencyVSAvoidhydraulic fluid leak onto turf
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically changes the operational state based on the detection status. Initially, the system allows continued operation with warning displayed to the operator. However, once the cutting units are raised, the system automatically shuts down the hydraulic mow circuit and blocks the lift and lower circuit, dynamically transitioning from a permissive state to a restrictive state to prevent further fluid leakage

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system provides continuous feedback through the warning device to inform the operator of the leak condition. The feedback mechanism ensures the operator is aware of the situation, and the automatic shutdown action provides definitive feedback that prevents further leakage regardless of operator response, closing the feedback loop

Inventive Principle:
Principle #23Feedback

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

Prevents turf damage by allowing continued operation without immediate shutdown, reducing hydraulic fluid leaks onto the turf.

Implementation Method 1

A solenoid valve with a temperature sensor increases the hydraulic fluid level in the sensing chamber if the temperature sensor indicates a hydraulic fluid temperature lower than a calculated reduced temperature

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 2

A solenoid valve with a temperature sensor increases the hydraulic fluid level in the sensing chamber if the temperature sensor indicates a hydraulic fluid temperature lower than a calculated reduced temperature

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP3871487B1Hydraulic leak detection method
Publication Date: 2025.07.16 DEERE & CO
  • EP3871487B1 patent drawingFigure 1
  • EP3871487B1 patent drawingFigure 2
  • EP3871487B1 patent drawingFigure 3

AI summary

A hydraulic leak detection system (100) includes a leak detection switch (112) responsive to a level of hydraulic fluid in a tank used by a hydraulic mowing circuit (108) and a lift and lower circuit (109) of a grass mowing machine (102). The system includes a controller (128) that activates a warning indicator (130) if the leak detection switch indicates the level of hydraulic fluid in the tank is low, but allows the hydraulic mowing circuit and the lift and lower circuit to continue operating until the lift and lower circuit reaches a fully raised position. A solenoid valve (116) may control the level of hydraulic fluid in the tank based on temperature of the hydraulic fluid.