Vehicle Drive Lubrication Control for Torque Limiting Under Oil Flow Faults
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Solution Overview
Problem
In vehicle drive devices, when the amount of heat generated by the transfer mechanism increases, the lubricating oil supply may become fixed at a low flow rate due to sticking in signal or switching valves, leading to potential overheating despite the need for a higher flow rate.
Innovation Solution
A vehicle drive device with a control system that can detect abnormal oil pressure supplying states and reduce the torque transferred between the drive source and wheels if the desired lubricating oil flow rate is not achieved, thereby preventing overheating by limiting the torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of lubricating oil supplied to the transfer mechanism is increased to deal with increased heat generation, then the cooling effect is improved, but the risk of valve sticking and abnormal states increases
Solution Approach 1:
The control part monitors the actual flow rate of lubricating oil supplied to the transfer mechanism and compares it with the instructed flow rate. When a discrepancy is detected (indicating valve sticking or abnormal state), the system automatically responds by limiting torque to prevent overheating, creating a closed-loop feedback control system that ensures reliable operation.
2Use of energy by moving object
If the flow rate switching valve is made switchable between high and low flow rates, then gas mileage is improved during steady traveling, but the system becomes more complex and prone to valve sticking
Solution Approach 1:
The system dynamically adjusts the flow rate of lubricating oil based on real-time monitoring of actual versus instructed flow rates. The control part can switch between high and low flow rates as needed, and when valve sticking is detected, it automatically limits torque to protect the transfer mechanism from overheating, making the system adaptable to changing conditions.
Solution Approach 2:
The control part continuously monitors the actual flow rate and compares it with the instructed flow rate to detect valve sticking or abnormal states. This feedback mechanism allows the system to identify problems early and take corrective action by limiting torque, ensuring reliable operation despite the added complexity of flow rate switching capability.
3Temperature
If the control part limits torque when abnormal state is detected, then overheating is prevented, but the power transmission capability is reduced
Solution Approach 1:
When valve sticking or abnormal state is detected through flow rate monitoring, the control part proactively limits torque before overheating can occur. This preliminary protective action prevents thermal damage to the transfer mechanism, though it temporarily reduces power transmission capability until the abnormal state is resolved.
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
This solution ensures that the transfer mechanism does not overheat even when the lubricating oil supply does not increase as intended, by reducing the torque load and thus preventing overheating.
Implementation Method 1
oil pressure generated by an oil pump is supplied as lubricating oil to the moving parts
Implementation Method 2
lubricating oil supplied to the transfer mechanism from the oil pressure control device to lubricate and cool the moving parts
Data Source
AI summary
An apparatus including a transmission mechanism in a power transfer path between a drive source and wheels; an oil pressure control device supplying lubricating oil to the transmission mechanism; and a control part outputting an electrical instruction to increase a flow rate of the supplied lubricating. When the control part outputs an electrical instruction to the oil pressure control device to increase a flow rate of lubricating oil supplied to the transmission mechanism, and determines that the flow rate of lubricating oil supplied to the transmission mechanism from the oil pressure control device does not increase as indicated by the electrical instruction (time t1), the control part considers that the oil pressure control device is in an abnormal state, and can impose a limitation that an absolute value of torque of the transmission mechanism transferred between the wheels and the drive source be reduced (time t1-t5).