Hydrostatic Speed Control for Engine Stall Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydrostatic systems in agricultural harvesting machines face challenges in maintaining constant cutter speed under varying power supply and loads, leading to engine speed droop and potential stalling, especially when the system attempts to increase speed during heavy loads, which can degrade performance and cause cutters to clog.
Innovation Solution
An automatic speed control system that monitors engine performance and switches between speed control and constant displacement modes, preventing further load on the engine during strain and automatically returning to normal operation when conditions improve, using a controller to manage the displacement of the hydrostatic system's pump and motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the automatic speed control increases pump displacement to maintain constant cutter speed under increased load, then cutter speed is maintained, but engine speed droop increases and stalling risk increases
Solution Approach 1:
The control system continuously monitors engine speed and uses this feedback to adjust pump displacement. When engine speed drops below a threshold, the system reduces pump displacement to prevent stalling, and when engine speed recovers, it gradually increases displacement to restore cutter speed, creating a closed-loop control that balances speed maintenance with engine protection
Solution Approach 2:
The system dynamically adjusts pump displacement based on real-time engine conditions rather than maintaining a fixed displacement setting. The control algorithm modifies the displacement command to the pump based on engine speed feedback, allowing the system to adapt between maintaining constant cutter speed under normal conditions and protecting the engine under high-load conditions
2Reliability
If the operator manually increases throttle position or decreases ground speed to prevent engine stalling, then engine performance is maintained, but overall machine productivity decreases
Solution Approach 1:
The control system automatically monitors engine conditions and adjusts pump displacement without requiring operator intervention. The system self-regulates by detecting engine speed droop and automatically reducing pump load, then restoring cutter speed when conditions improve, eliminating the need for operators to manually adjust throttle or ground speed to prevent stalling
3Adaptability or versatility
If the hydrostatic system operates under varying power supply and loads, then system versatility is improved, but maintaining constant cutter speed becomes difficult
Solution Approach 1:
The system uses speed feedback from the cutter drive motor to continuously monitor actual cutter speed and compares it to the desired setpoint. The control algorithm calculates the speed error and adjusts pump displacement accordingly, enabling the system to maintain constant cutter speed despite variations in engine power availability and cutting load conditions
Data Source
AI summary
A hydrostatic system and method of operation thereof, wherein at least one of a fluid motor and a pump of the system has a displacement which is variable for controlling a speed of operation of the motor, the pump being driven by an engine, and a controller configured for monitoring the speed of operation of the motor and an operating characteristic of the engine and automatically controlling the displacement responsive thereto, wherein if the operating characteristic is indicative of engine performance above a predetermined threshold, the controller will control the displacement for maintaining the speed of operation of the motor at about a predetermined value, and, if the operating characteristic is indicative of engine performance below the threshold, the controller will hold the displacement at a constant value. As a result, the controller can prevent the system from further decreasing the engine performance. And, if the engine performance increases to that or another threshold, the controller will automatically switch back to controlling the displacement for holding the motor speed at the predetermined value, optionally including to incrementally increase the speed to the predetermined value.