Hydraulic Flow Prioritization for Lift Arm and Attachment Actuators
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Solution Overview
Problem
In working machines like compact track loaders, when the lift arm cylinders and attachment hydraulic actuators are actuated concurrently, the combined flow rate requirements often exceed the maximum delivery flow rate of the shared hydraulic pump, leading to reduced flow rates for both systems and compromised work efficiency.
Innovation Solution
A hydraulic system with a special flow rate control system that includes a hydraulic pump, manual operators to set required flow rates, flow rate controllers to match supply flow rates with set requirements, and a system to reduce the supply flow rate of one actuator if the total required flow rate exceeds the pump's maximum delivery flow rate, ensuring that the higher-priority actuator receives the required flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sum of the required flow rate of the lift arm cylinders and the required flow rate of the hydraulic actuator of the attachment exceeds the maximum delivery flow rate of the hydraulic pump, then the flow rate supplied to both systems decreases below required levels, but if the pump capacity is increased, then the system complexity and cost increase
Solution Approach 1:
The hydraulic system dynamically adjusts flow rate distribution between lift arm cylinders and attachment actuators based on real-time demand. The control system continuously monitors required flow rates and automatically reallocates hydraulic fluid flow to prioritize critical functions when total demand exceeds pump capacity, eliminating the need for oversized pump equipment.
Solution Approach 2:
The system changes flow rate parameters dynamically by using variable displacement hydraulic pumps and flow control valves to adjust the volume of hydraulic fluid delivered to different actuators. This allows the same hydraulic system to adapt to varying operational demands without requiring multiple fixed-capacity pumps.
2Reliability
If the hydraulic pump delivers maximum flow rate to meet the higher priority actuator's demand, then the lower priority actuator receives reduced flow rate, but if both actuators receive equal flow rate, then neither achieves required performance
Solution Approach 1:
The hydraulic system applies different flow rate qualities to different actuators based on their priority and functional requirements. Critical actuators such as lift arm cylinders receive higher flow rates to ensure reliable operation, while non-critical actuators receive reduced flow rates when resources are limited, optimizing overall system reliability.
Solution Approach 2:
The control system continuously monitors the operational status and flow rate requirements of all hydraulic actuators, using this feedback to dynamically adjust flow distribution. When the system detects that total demand exceeds supply capacity, it automatically prioritizes critical functions and reallocates flow to maintain essential work performance.
Data Source
AI summary
A hydraulic system for a working machine includes first and second hydraulic actuators actuated by hydraulic fluid delivered by a hydraulic pump, a first flow rate controller to control a first supply flow rate of hydraulic fluid supplied to the first hydraulic actuator to match a first required flow rate, a second flow rate controller to control a second supply flow rate of hydraulic fluid supplied to the second hydraulic actuator to match a second required flow rate, and a special flow rate control system to, if a sum of the first and second required flow rates is greater than a maximum delivery flow rate of the hydraulic pump, reduce the first supply flow rate to allow the second supply flow rate to approach the second required flow rate.