IVT Control Adjusting Output for Engine Load Stability
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Solution Overview
Problem
Work machines with internal combustion engines coupled with infinitely variable transmissions face issues such as engine speed drops and potential stalling due to sudden loads, and excessive wheel slippage or engine overload when external hydraulic functions are activated, as the response time to adjust IVT ratios is slower than needed to prevent these conditions.
Innovation Solution
Implementing at least one sensor to provide real-time load values to an electrical processing circuit, which sets a threshold load value for the IC engine and controls the IVT output based on this comparison to prevent overload conditions, allowing for dynamic adjustment of IVT output to match changing load demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the IVT ratio is adjusted to respond to sudden loads, then engine speed stability is improved, but the response time of the IVT system is too slow to prevent substantial engine speed drop and stalling
Solution Approach 1:
The control system performs preliminary action by detecting engine load conditions in advance and proactively adjusting the IVT ratio before substantial engine speed drop occurs. The processor continuously monitors load sensors and preemptively modifies transmission ratios to prevent overload conditions, rather than merely reacting after speed drops are detected.
Solution Approach 2:
The system implements feedback control by continuously monitoring engine load through sensors and comparing actual load values against threshold values. The processor uses this feedback loop to dynamically adjust IVT ratios, creating a closed-control system that responds to changing load conditions in real-time, thereby maintaining engine speed stability despite the inherent response time limitations of the IVT mechanism.
2Speed
If the IVT output torque and speed are increased to match operator commands, then vehicle speed capability is improved, but excessive wheel slippage and engine overload occur under external loads
Solution Approach 1:
The control system applies preliminary anti-action by detecting external load conditions (such as hydraulic function activation) in advance and counteracting their harmful effects by reducing IVT output torque and speed before engine overload or excessive wheel slippage occurs. This preemptive reduction prevents the harmful conditions while still allowing the operator to command higher speeds when load conditions permit.
Solution Approach 2:
The system dynamically changes operating parameters by adjusting IVT ratio based on detected load conditions. When external loads are detected through sensor inputs, the processor modifies transmission parameters (ratio, output torque, output speed) to keep the engine operating within safe load boundaries, thereby preventing overload while optimizing vehicle performance under varying load conditions.
3Reliability
If real-time load monitoring and dynamic IVT control are implemented, then engine overload prevention is improved, but system complexity increases due to additional sensors and control circuits
Solution Approach 1:
The control system achieves multi-functionality by using the existing IVT control processor to perform both standard transmission control functions and the new load monitoring/protection functions. The processor leverages existing sensor inputs (load sensors, position sensors) and integrates the threshold comparison and dynamic ratio adjustment logic into its existing control architecture, thereby implementing comprehensive engine protection without requiring entirely separate control systems.
Solution Approach 2:
The system introduces an intermediary control layer (the processor with threshold comparison logic) that mediates between sensor inputs and IVT actuation. This intermediary layer processes load information, compares it against threshold values, and generates appropriate control signals, thereby simplifying the overall system architecture while enabling sophisticated load management without direct complex connections between all components.
Data Source
AI summary
A work machine includes an internal combustion (IC) engine, and an infinitely variable transmission (IVT) coupled with the IC engine. At least one sensor provides an output signal representing a real-time load value on the IC engine. At least one electrical processing circuit is configured for controlling an output of the IVT, dependent upon a threshold load value for the IC engine and the real-time load value for the IC engine. In one embodiment, the at least one electrical processing circuit includes an engine control unit (ECU) associated with the IC engine, and a transmission control unit (TCU) associated with the IVT. The ECU provides an output signal to the TCU representing the real-time load value. The TCU controls the output of the IVT dependent upon a comparison between the threshold load value and the real-time load value.