Epicyclic Pump Drive for Transmission Fluid Flow Control
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Solution Overview
Problem
In vehicle transmissions, excessive transmission fluid flow at high speeds reduces efficiency, and existing systems require complex fluid flow features to manage flow direction, especially when reversing, increasing system complexity and weight.
Innovation Solution
A system using an epicyclic gear set and a controller to regulate the rotational speed of a pump driver, ensuring transmission fluid flows at a pre-specified rate and temperature, eliminating the need for non-return valves by maintaining flow direction consistency across speeds and reversing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump arrangement is configured to cause transmission fluid to flow at a suitable rate when travelling slowly, then the fluid flow is adequate at low speeds, but at high vehicle travelling speed an excessive flow of transmission fluid arises which reduces overall transmission efficiency
Solution Approach 1:
The pump driver's rotational speed is dynamically adjusted based on vehicle speed conditions. The system transitions from a fixed-speed pump configuration to a variable-speed pump driven by the epicyclic gear set, which automatically adapts the pump speed to match vehicle operating conditions, preventing excessive fluid flow at high speeds while maintaining adequate flow at low speeds
Solution Approach 2:
The system changes the operational parameters of the pump by varying its rotational speed. Through the epicyclic gear set's speed reduction mechanism, the pump driver operates at different speeds depending on vehicle conditions, thereby controlling the transmission fluid flow rate parameter to optimize efficiency across different operating ranges
2Adaptability or versatility
If fluid flow features (e.g. non-return valves) are added to redirect the flow of transmission fluid, then the system can function when the vehicle travels in reverse, but the device complexity increases
Solution Approach 1:
The invention extracts and eliminates the need for complex fluid flow redirecting features such as non-return valves and flow redirection passages. By using the epicyclic gear set's inherent mechanical properties, the system achieves reverse operation capability without requiring additional fluid control components, thereby simplifying the overall system
Solution Approach 2:
The epicyclic gear set serves multiple functions: it reduces pump driver speed, enables bidirectional operation for reverse capability, and maintains simple fluid flow paths. This multi-functional component replaces what would otherwise require separate dedicated components for speed control and reverse operation, reducing overall system complexity
Data Source
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AI summary
Apparatus for managing fluid flow in a vehicle, comprising: an epicylic gear set having first and second inputs configured to receive rotational drive input from a torque output feature of a powertrain and a rotary actuator respectively; a pump driver for driving a fluid pump, the pump driver configured to receive rotational drive input from an output of the epicylic gear set; and a controller configured to determine information corresponding to the rotational speed of the torque output feature using information generated by a rotational speed sensor and based on this control the rotary actuator such that the pump driver is caused to rotate at substantially a pre-specified speed.