Hydraulic Pump Input Signal Scaling for Proportional Control
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Solution Overview
Problem
Existing refuse vehicles face challenges in maintaining pump proportional control when the request for fluid power exceeds the maximum capacity of the hydraulic system, leading to loss of proportional control and additional costs due to the implementation of compensation valves.
Innovation Solution
A processing circuit modifies input signals to adjust the amount of fluid power provided to vehicle components, ensuring proportional control by reducing the request to a level below the hydraulic system's threshold, thereby maintaining the intended relationship between operator input and component movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hydraulic system is designed to provide high fluid power capacity, then the maximum power availability is improved, but the system complexity and cost increase due to requiring compensation valves
Solution Approach 1:
The patent replaces mechanical compensation valves with an electronic control system that modifies input signals to the hydraulic pump. The processing circuit receives operator inputs, determines the requested fluid power level, and adjusts the control signal to the hydraulic pump to prevent exceeding maximum capacity, thereby eliminating the need for mechanical compensation valves while maintaining proportional control.
Solution Approach 2:
The patent changes the parameter being controlled from direct hydraulic pressure/flow compensation to modified input signal levels. By adjusting the electrical control signal parameters sent to the hydraulic pump based on current system state and requested power levels, the system prevents overload conditions without requiring additional hydraulic compensation components.
2Reliability
If compensation valves are added to maintain proportional control at maximum capacity, then the reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent substitutes mechanical compensation valves with an electronic processing circuit that modifies control signals. This electronic approach maintains proportional control reliability across the full operating range without requiring additional mechanical components, simplifying manufacturing and reducing costs.
Solution Approach 2:
The patent introduces a processing circuit as an intermediary between the operator input device and the hydraulic pump. This intermediary modifies control signals to ensure the hydraulic system operates within its maximum capacity while maintaining proportional control, replacing the need for compensation valves.
3Productivity
If the hydraulic system operates at maximum fluid power capacity, then the productivity is improved, but the loss of proportional control occurs when the threshold is exceeded
Solution Approach 1:
The patent implements a feedback mechanism where the processing circuit continuously monitors the requested fluid power level against the maximum capacity threshold. When the threshold is approached or exceeded, the circuit modifies the control signal to maintain proportional control, providing feedback-based protection while allowing full productivity utilization.
Solution Approach 2:
The patent makes the control system dynamic by continuously adjusting the control signal to the hydraulic pump based on real-time operating conditions. The processing circuit dynamically modifies input signals to maintain proportional control across varying load conditions while preventing threshold exceedance.
Data Source
AI summary
A refuse vehicle can include a first element, a hydraulic system, and one or more processing circuits. The one or more processing circuits can receive a first input to control the first element to cause the first element to perform a first operation of the refuse vehicle, obtain first information to indicate a metric associated with an energy source of the hydraulic system, determine that a first amount of fluid power exceeds a fluid power threshold for the hydraulic system, and modify the first input to reduce a request from the first amount of fluid power to a second amount of fluid power.