Hydraulic Pump Pressure Control for Shock-Free Construction Operation
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Solution Overview
Problem
Conventional hydraulic pump control systems in construction machines waste fuel and cause manipulation shocks due to abrupt reduction in flow rate when load pressure exceeds a preset value, leading to inefficient operation and poor operator feedback.
Innovation Solution
A hydraulic pump control system that proportionally reduces the discharge flow rate of the hydraulic pump in response to load pressure, using a control unit to manage the flow rate based on detected pressure and manipulation inputs, and includes a system pressure boost-up function to prevent drive speed reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main relief valve allows hydraulic fluid to be drained to the hydraulic tank when load pressure exceeds a preset value, then the hydraulic components are protected from damage, but fuel is wasted unnecessarily due to continuous discharge of the hydraulic pump
Solution Approach 1:
The patent applies dynamics by making the hydraulic pump's displacement variable rather than fixed. The control unit adjusts the pump's discharge flow rate dynamically based on real-time load pressure feedback, allowing the system to adapt to changing conditions and avoid unnecessary continuous discharge that wastes fuel while still protecting components when needed.
Solution Approach 2:
The patent implements feedback control by using a pressure detector to monitor load pressure continuously and feeding this information back to the control unit. The control unit then adjusts the pump's discharge flow rate accordingly, creating a closed-loop system that optimizes fuel efficiency while maintaining component protection through proportional flow rate adjustment based on actual pressure conditions.
2Loss of energy
If the relief valve is turned on or off when discharge pressure exceeds the preset value to reduce flow rate loss, then the flow rate loss is reduced, but a shock occurs in the hydraulic system resulting in deterioration of manipulation feeling
Solution Approach 1:
The patent resolves this contradiction by implementing dynamic, proportional adjustment of the discharge flow rate rather than abrupt on/off valve operation. The control unit continuously modulates the pump's flow rate in proportion to the degree by which load pressure exceeds the preset value, creating a smooth transition that reduces flow rate loss without causing shocks to the hydraulic system or deterioration of manipulation feeling.
Solution Approach 2:
The patent applies parameter changes by continuously adjusting the discharge flow rate parameter based on load pressure conditions. Instead of maintaining a fixed flow rate and using relief valves to dump excess pressure, the system varies the flow rate parameter proportionally to pressure conditions, achieving both energy efficiency and smooth operation without abrupt changes that cause shocks.
3Loss of energy
If the discharge flow rate of the hydraulic pump is abruptly reduced when load pressure exceeds the preset value, then the flow rate loss is reduced, but a shock occurs in the hydraulic system
Solution Approach 1:
The patent applies beforehand cushioning by implementing proportional, gradual reduction of the discharge flow rate before pressure buildup can cause harmful shocks. The control unit anticipates pressure issues by continuously monitoring load pressure and adjusting the flow rate in proportion to pressure conditions, cushioning against potential shocks through smooth, progressive adjustment rather than abrupt changes.
Solution Approach 2:
The patent resolves the contradiction between reducing flow rate loss and preventing shocks by making the flow rate adjustment dynamic and proportional. The control unit continuously adapts the discharge flow rate based on real-time load pressure feedback, creating a smooth, progressive reduction that eliminates abrupt changes and their associated shocks while still achieving energy efficiency through appropriate flow rate management.
Data Source
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AI summary
Disclosed is a system for controlling a hydraulic pump in a construction machine which can reduce the discharge flow of the hydraulic pump in proportion to the load pressure of the hydraulic pump to enhance operability by the driver. The present invention provides the system for controlling the hydraulic pump in the construction machine, which is characterized by detecting the discharge pressure of the hydraulic pump and the operation activity of an operation lever, and comparing the detected discharge pressure of the hydraulic pump and a predetermined pressure value, and when the detected discharge pressure exceeds the predetermined pressure value, the maximum dischargeable flow of the hydraulic pump is reduced in proportion to the difference between the detected pressure and the predetermined pressure value.