Agricultural Vehicle Clutch Thermal Load Management
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Solution Overview
Problem
Existing control systems for agricultural and industrial off-highway vehicle transmissions fail to efficiently manage clutch plate temperature, leading to reduced performance and excessive wear, especially in challenging conditions.
Innovation Solution
A control system that includes a thermal load managing device to regulate the power balance between the clutch and lubricating oil, using strategies such as torque saturation, speed limitation, and increased oil flow to maintain clutch plate temperature within safe thresholds, thereby preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the clutch is operated at maximum performance to maintain transmission efficiency, then power transmission capability is improved, but clutch plate temperature increases leading to excessive wear
Solution Approach 1:
The control system continuously monitors clutch operating conditions including temperature, slip condition, and power transmission demands. Based on this feedback, the controller dynamically adjusts the torque reference sent to the clutch actuator, reducing torque when temperature thresholds are approached and allowing maximum torque when cooling capacity is sufficient. This closed-loop control enables the clutch to operate at maximum performance when conditions permit while preventing thermal damage.
Solution Approach 2:
The system dynamically adapts clutch operation based on real-time thermal conditions and cooling capacity. The torque reference is not fixed but varies continuously according to the balance between thermal power generated by clutch friction and thermal power removed by the lubricating oil flow. This dynamic adjustment allows the clutch to operate at optimal performance levels under varying thermal conditions.
2Temperature
If torque is reduced to control clutch plate temperature, then temperature is contained, but clutch performance decreases
Solution Approach 1:
The system changes the torque parameter dynamically based on thermal conditions. When the lubricating oil flow rate increases and cooling capacity improves, the controller increases the torque reference, allowing the clutch to transmit higher power. When cooling capacity is limited, the torque reference is reduced to prevent excessive temperature rise. This parameter adjustment enables optimal balance between temperature control and performance.
Solution Approach 2:
The control system implements periodic modulation of torque during clutch engagement and operation. By oscillating the torque reference around optimal values based on thermal feedback, the system prevents thermal runaway while maintaining average performance close to maximum capability. This periodic action allows the clutch to operate near thermal limits without exceeding safe temperature thresholds.
3Temperature
If the lubricating oil flow rate is increased to remove thermal power, then temperature control is improved, but system complexity and energy consumption increase
Solution Approach 1:
The control system utilizes existing sensors and actuators already present in the transmission system for temperature management. The same sensors that monitor clutch operation (temperature, speed, torque) are used to determine cooling capacity, and the same clutch actuator is used to adjust torque as a cooling strategy. No separate dedicated cooling control hardware is required, as the existing system serves dual purposes of power transmission and thermal management.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively controls clutch plate temperature, maintaining performance while reducing wear and ensuring efficient power transmission.
Implementation Method 1
thermal power removed by the lubricating oil flow rate
Implementation Method 2
thermal power removed by the lubricating oil flow rate
Implementation Method 3
thermal power generated by the clutch plates through friction in the slipping condition
Data Source
AI summary
A control system for the transmission of an agricultural vehicle or an industrial off-highway vehicle, wherein the system comprises a controller of the clutch, connected thereto to supply an operating signal, a plurality of sensors suitable for measuring a plurality of characteristic quantities of the transmission and connected to the controller to supply a plurality of signals proportional to the quantities, a torque processor suitable for calculating a reference torque and connected to the controller to supply thereto a signal proportional to the reference torque, and a thermal load managing device suitable for receiving at least some of the plurality of quantities and for receiving the reference torque in order to calculate at least one operative datum on which the thermal power exchanged in the clutch is dependent. The control system is suited to process the operative datum to operate the transmission so as to limit the temperature in the clutch.