Hydraulic Valve Sticking Detection in Closed-Circuit Construction Machinery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In construction machines with closed circuit hydraulic drive systems, stuck-open surplus flow control valves can cause unintended hydraulic cylinder operations, leading to reduced productivity and operational efficiency, as existing failure diagnosis methods require machine stoppage for diagnosis.
Innovation Solution
A system with a closed circuit unit, an open circuit unit, and a control unit that includes pressure sensors and controllers to detect and manage the stuck-open state of surplus flow control valves in real-time, allowing continuous operation without reducing machine speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing failure diagnosis methods are used to detect stuck-open surplus flow control valves, then diagnostic accuracy is improved, but machine operation must be stopped reducing productivity
Solution Approach 1:
The system performs preliminary actions by continuously monitoring pressure values during normal operation and pre-judging the stuck-open state of the surplus flow control valve before actual failure occurs. This allows early detection and warning without requiring machine stoppage, thus maintaining productivity while ensuring reliability through advance fault prediction
Solution Approach 2:
The pressure monitoring and judgment system operates continuously during machine operation, enabling uninterrupted detection of valve status. This continuous monitoring ensures that the useful action of detecting valve failures persists without interruption, maintaining both diagnostic capability and operational continuity
2Productivity
If real-time pressure monitoring is implemented during operation, then productivity is maintained, but system complexity increases
Solution Approach 1:
The pressure sensor serves multiple functions: it monitors system pressure for normal operation control and simultaneously detects stuck-open states of the surplus flow control valve. This multi-functionality reduces the need for separate diagnostic hardware, thereby limiting the increase in system complexity while enabling continuous operation and real-time fault detection
Solution Approach 2:
The system uses the existing pressure monitoring infrastructure to self-diagnose valve failures without requiring additional external diagnostic equipment. By leveraging already-present sensors and control units, the system performs self-service fault detection, minimizing added complexity while maintaining continuous operational monitoring
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
Enables real-time detection and management of stuck-open surplus flow control valves, preventing abrupt hydraulic cylinder operations and maintaining operational efficiency and productivity.
Implementation Method 1
a pressure sensor that measures a delivery pressure of the open circuit pump
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a construction machine capable of detecting a stuck-open state of a surplus flow control valve in real time during operation without involving a reduction in the operational speed. The construction machine is equipped with: a surplus flow control valve control section configured to output a closing command to a first surplus flow control valve at the operation start when an operation amount signal of an operation lever device is detected; a pump delivery control section configured to output a delivery flow rate command to an adjustment section of an open circuit pump; an assist valve control section configured to continue to output a closing command from before to an assist valve; a sticking detection determination section configured to compare a pressure signal with a previously set threshold value and determining that the surplus flow control valve is in a stuck-open state when the pressure signal is less than the threshold value and determining that the surplus flow control valve is normal when the pressure signal exceeds the threshold value; and a stop signal generating section configured to input therein a sticking determination signal, output in the case of a stuck-open state a control signal maintaining a closed state of the assist valve to the assist valve control section, and output in the case of a normal state a control signal causing the assist valve to perform an opening operation to the assist valve control section.