Hydraulic Excavator Area Limiting Control Engine Speed Management
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Solution Overview
Problem
In hydraulic excavators equipped with both low engine speed control and area limiting control, the sudden increase in engine speed during the transition from low engine speed control to area limiting control can compromise the control accuracy of the work implement, leading to potential intrusion of the implement under the target surface.
Innovation Solution
A switching device is implemented to selectively enable or disable low engine speed control based on the operation lever status, ensuring that low engine speed control is not executed when area limiting control is required, thereby maintaining consistent actuator speed and control accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low engine speed control is executed to improve fuel efficiency, then fuel consumption is reduced, but actuator speed fluctuates and control accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts engine speed control based on operational context. When area limiting control is active, the engine control section maintains normal engine speed despite idle lever conditions, preventing actuator speed fluctuations that would occur with low engine speed control. This dynamic adaptation resolves the contradiction by selecting the appropriate engine speed regime based on the current control mode.
2Loss of energy
If low engine speed control is activated during finishing operation, then fuel efficiency improves, but engine speed increases suddenly when area limiting control resumes, causing actuator speed fluctuation
Solution Approach 1:
The system performs preliminary assessment of control mode status before executing engine speed control. The engine control section checks whether area limiting control is active before deciding on low engine speed control execution. This preliminary check prevents the harmful sequence of low engine speed control followed by sudden engine speed increase, thereby maintaining actuator speed stability.
3Manufacturing precision
If area limiting control is executed to maintain work implement position accuracy, then positioning precision is improved, but engine speed must be maintained at normal levels preventing fuel efficiency improvement
Solution Approach 1:
The system applies different engine speed control strategies to different operational contexts. When area limiting control is active (requiring high position accuracy), normal engine speed is maintained. When area limiting control is inactive and idle conditions are detected, low engine speed control is applied for fuel efficiency. This localized control approach optimizes both precision and energy consumption in their respective contexts.
Data Source
AI summary
A work machine (1) having a controller (40) that can perform area limiting control, the work machine further includes a machine control ON/OFF switch (17) that alternatively selects an ON position permitting execution of the area limiting control and an OFF position prohibiting execution of the area limiting control. The controller (40) has an engine control section (63) that performs automatic idling control when a predetermined period of time (T1) has elapsed after a point in time when all of operation levers (1, 23) have attained a neutral state. The engine control section (63) is configured to execute the automatic idling control during when the switch (17) is in the OFF position and not to execute the automatic idling control during when the switch (17) is in the ON position.