Excavator Pilot Hydraulic Pressure Monitoring for Unloading Valve Faults
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing hydraulic control systems of hydraulic excavators face challenges in detecting abnormalities in the pump output power switching device, particularly when the unloading valve is stuck at the interruption, communication, or intermediate positions, leading to inadequate fuel consumption optimization and potential hydraulic fluid loss.
Innovation Solution
A hydraulic control system that includes a pump output power switching device, an accumulator, a pump check valve, a pressure sensor, and a controller with an abnormality determination section. The controller computes the command continuation time and determines abnormality based on predetermined values, enabling independent detection of pump output power switching device issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the unloading valve is stuck at the interruption position, then the accumulator can accumulate hydraulic fluid, but the output power of the pilot pump cannot be reduced and fuel consumption cannot be improved
Solution Approach 1:
The system uses pressure sensors to detect hydraulic fluid pressure and provides feedback to the controller. The controller monitors this feedback information to determine whether the unloading valve is functioning properly or stuck, enabling real-time detection and response to valve abnormalities.
Solution Approach 2:
The patent replaces purely mechanical valve operation monitoring with an electronic detection system using pressure sensors and a controller. This substitution allows for more reliable and precise detection of valve status compared to traditional mechanical monitoring methods.
2Use of energy by moving object
If the unloading valve is stuck at the communication position, then fuel consumption is reduced, but hydraulic fluid in the accumulator is lost over time and the pilot valve loses function
Solution Approach 1:
Pressure sensors continuously monitor the hydraulic system and provide feedback to the controller. When the controller detects abnormal pressure patterns indicating the unloading valve is stuck at the communication position, it can identify the abnormality and alert the operator to prevent hydraulic fluid loss and pilot valve failure.
Solution Approach 2:
The system provides early warning through abnormality detection before actual hydraulic fluid loss or pilot valve failure occurs. This allows operators to take preventive measures, cushioning against the harmful effects of stuck valve operation.
3Measurement precision
If traditional pressure sensor detection is used, then abnormality can be detected when pressure deviates from normal range, but abnormalities when the valve is stuck at interruption or intermediate positions cannot be detected
Solution Approach 1:
The controller receives continuous feedback from pressure sensors and analyzes pressure patterns over time. By monitoring how pressure changes in response to controller commands, the system can detect abnormalities regardless of which position the unloading valve is stuck in, providing comprehensive detection coverage.
Solution Approach 2:
The system dynamically monitors pressure changes over time rather than relying on static pressure thresholds. This dynamic approach allows the detection system to identify abnormalities in various valve positions by observing pressure behavior patterns, enhancing adaptability across different stuck positions.
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 the detection of abnormalities in the pump output power switching device, regardless of its operational state, thereby optimizing fuel consumption and preventing hydraulic fluid loss by accurately determining when the unloading valve is stuck.
Implementation Method 1
the accumulator accumulates a portion of the hydraulic fluid delivered from the pilot pump, and supplies the hydraulic fluid to the pilot valve
Implementation Method 2
The pump check valve permits the flow of the hydraulic fluid from the pilot pump to the pilot valve and the accumulator, and prevents the flow of the hydraulic fluid from the accumulator to the pilot pump
Implementation Method 3
The pressure sensor detects the pressure of the hydraulic fluid supplied to the pilot valve and outputs it to the controller
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Provided is a work machine hydraulic control system capable of detecting abnormality in a pump output power switching device independently of the abnormality state of the pump output power switching device. A hydraulic control system of a hydraulic excavator is equipped with an accumulator 21 connected to a hydraulic line 25A between a pilot pump 17 and a pilot valve 20, an unloading valve 27 that is a pump output power switching device, a pressure sensor 29 detecting the pressure of the hydraulic fluid supplied to the pilot valve 20, and a controller 30 having a pump output power control section 31 switching the unloading valve 27 in accordance with the pressure detected by the pressure sensor 29. The controller 30 further has an abnormality determination section 32 that computes a command continuation time in a state in which a command output to the unloading valve 27 is not changed. In the case where this command continuation time is not less than a predetermined value, it determines that the unloading valve 27 is abnormal, and outputs the determination result.