Power-Split Gearbox Cruise Control With Capacity Utilization Feedback
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Solution Overview
Problem
Existing drive systems in working machines with power-split gearboxes struggle to operate at a constant speed efficiently, leading to inefficiencies and increased operating costs.
Innovation Solution
A method for operating a drive device with a power-split gearbox that includes setting a target output speed based on operator input, recording actual capacity utilization, and adjusting engine speed to maintain efficiency, using a control device to manage the power-split gearbox and engine for continuous adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the working machine operates at a constant speed using a power-split gearbox with variator, then the transmission ratio can be continuously adjusted to maintain speed, but the capacity utilization of the engine and gearbox deteriorates, leading to reduced efficiency
Solution Approach 1:
The control device continuously monitors the actual capacity utilization of the engine and gearbox, comparing it with target values. Based on this feedback, the control device adjusts the engine speed dynamically to maintain optimal capacity utilization while preserving the desired constant output speed. This closed-loop control resolves the contradiction by actively compensating for efficiency losses.
Solution Approach 2:
Instead of operating the engine at a fixed speed, the system dynamically adjusts the engine speed based on real-time capacity utilization measurements. The engine speed is varied within a range while maintaining the output speed constant, allowing the system to adapt to changing load conditions and maintain optimal efficiency points on the engine and gearbox maps.
2Use of energy by moving object
If the engine speed is adjusted to improve capacity utilization, then efficiency improves, but the output speed may deviate from the target speed
Solution Approach 1:
The control device uses feedback control to simultaneously manage engine speed and output speed. By continuously monitoring both the capacity utilization and the actual output speed, the system adjusts the engine speed to maintain optimal efficiency while compensating for any deviations in output speed. This ensures both efficiency and speed stability are maintained.
Solution Approach 2:
The system changes the engine speed parameter dynamically while keeping the output speed constant. By adjusting the engine operating point (speed and load) based on pre-defined efficiency maps and real-time measurements, the system can move along different operating curves to maintain optimal capacity utilization without affecting the final output speed.
3Stability of the object's composition
If cruise control is implemented to maintain constant speed, then speed stability improves, but the complexity of the control system increases
Solution Approach 1:
The control device performs multiple functions: it manages the variator for continuous transmission ratio adjustment, controls engine speed for optimal capacity utilization, and implements cruise control for speed stability. By integrating these functions into a single control unit that uses a unified feedback mechanism, the system achieves speed stability without proportionally increasing complexity.
Solution Approach 2:
The patent combines the cruise control functionality with the existing power-split gearbox control and engine management system. Instead of adding a separate cruise control system, the control device integrates speed stabilization with capacity utilization optimization, merging multiple control objectives into a single coordinated control strategy.
Data Source
AI summary
A method is provided for operating a drive device for a working machine, where the drive device has an engine and a power-split gearbox with a variator for continuously variable adjustment of the transmission ratio of the gearbox. The method includes outputting a target output speed of the drive device based on a target speed request from an operator of the working machine. The method further includes recording an actual capacity utilization of the drive device and comparing the recorded actual capacity utilization with a target capacity unitization of the drive device. The method further includes outputting a target engine speed of the engine based on the comparison of the actual and target capacity utilization of the drive device.