Hydraulic Flow Sharing Control for Prime Mover Stall Prevention
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Solution Overview
Problem
Hydraulic systems in work machines, such as excavators, often face prime mover stall due to insufficient power, requiring additional control equipment and components like torque controllers and electronic displacement control pumps, which increase costs.
Innovation Solution
A control approach that generates a flow vs pressure map from the prime mover speed-torque/power curve to determine the maximum available flow without stalling, and adjusts control valve spools to match the required flow demand, reducing the pump output flow to prevent prime mover stall without additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional control equipment (torque controller, electronic displacement control pump) is added to prevent prime mover stall, then prime mover stall prevention capability is improved, but device complexity and cost increase
Solution Approach 1:
The existing supervisory controller performs dual functions: normal hydraulic control and prime mover stall prevention. The controller uses its existing computational resources to generate flow vs pressure maps from prime mover speed-torque curves and compares required flow with available flow to prevent stall, eliminating the need for dedicated stall prevention hardware
Solution Approach 2:
The existing supervisory controller is extended to handle both standard hydraulic control operations and prime mover stall prevention. The same controller hardware and software platform that manages normal hydraulic functions now also monitors prime mover speed, generates flow maps, and controls flow distribution to prevent stall conditions
2Reliability
If additional control components (torque controller, separate control valve) are added to control pump torque and prevent stall, then prime mover stall prevention is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the stall prevention control function with the existing hydraulic control valve system. The supervisory controller integrates flow distribution control directly into the valve control architecture, merging multiple control functions into a unified system that reduces component count and manufacturing complexity
3Reliability
If electronic displacement control pump is used to prevent prime mover stall, then stall prevention capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical torque control systems with a software-based control approach. Instead of using mechanical torque controllers or electronic displacement control pumps, the system uses computational algorithms in the supervisory controller to generate flow vs pressure maps and dynamically adjust flow distribution through existing valves, substituting mechanical complexity with software intelligence
Data Source
AI summary
A method for preventing prime mover stall for a work machine including a hydraulic system having a plurality of control valves served by a hydraulic pump. The method can include determining an actual required flow rate value for the plurality control valves and a total maximum flow rate to the plurality of control valves that will enable the prime mover to operate without stalling. The method can also include operating the plurality of control valves such that the combined total flow of the plurality control valves is at or below the total maximum flow rate such that the pump operates at a condition below which prime mover stall will occur. The method can also include setting a flow sharing allocated specific criteria in which the flow reduction takes place during a flow saturation condition for each of the plurality of control valves such that the total sum of the flow rates (calculated based on the criteria) is equal to or less than the total maximum flow rate.