Transmission Fluid Pump Drive With Epicyclic Speed Control
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Solution Overview
Problem
In vehicle transmissions, existing pump arrangements often result in excessive fluid flow at high speeds, reducing efficiency and requiring complex fluid flow features to manage flow direction during reverse travel, which increases system complexity and weight.
Innovation Solution
An epicyclic gear set with a rotary actuator and temperature sensor-controlled pump driver maintains fluid temperature within specified limits by adjusting rotational speed, ensuring consistent fluid flow across varying vehicle speeds and directions without the need for non-return valves, thereby optimizing transmission efficiency and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pump arrangement is configured to cause transmission fluid to flow at a suitable rate when travelling slowly, then 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 and fluid temperature through the controller. The epicyclic gear set enables variable speed operation where the pump driver can rotate faster than the vehicle's powertrain output, allowing the system to optimize fluid flow rate according to actual operating conditions rather than running at constant speed.
Solution Approach 2:
The system changes operational parameters (rotational speed, fluid temperature) to optimize performance. The controller monitors fluid temperature and vehicle speed, then adjusts the pump driver's rotational speed accordingly. Fluid temperature is used as a parameter to indicate whether the fluid is too viscous (needs heating via increased flow) or sufficiently warm (flow should be reduced to avoid excess).
2Reliability
If a pump arrangement is configured to manage fluid flow at low speeds, then adequate lubrication is provided, but complex fluid flow features (e.g. non-return valves) are required to redirect flow during reverse travel
Solution Approach 1:
Instead of using complex flow redirection mechanisms like non-return valves to manage reverse flow, the system inverts the approach by controlling the pump driver's rotational speed and direction through the epicyclic gear set. The pump driver can be rotated in either direction at controlled speeds, eliminating the need for one-way flow restriction devices and their associated complexity.
3Productivity
If the pump driver rotates at high speed to maintain adequate fluid flow, then fluid circulation is sufficient, but fluid temperature increases excessively
Solution Approach 1:
The system uses fluid temperature as feedback to control pump driver operation. The controller continuously monitors fluid temperature and adjusts the pump driver's rotational speed in response. When fluid becomes too hot, the controller reduces the pump driver's speed to decrease circulation and allow temperature to stabilize, creating a self-regulating thermal management system.
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 maintains optimal transmission fluid flow rates across a range of speeds and directions, enhancing efficiency and reducing system complexity and weight by eliminating the need for complex fluid flow features, ensuring consistent performance and improved energy management.
Implementation Method 1
an epicyclic gear set having first and second inputs configured to receive rotational drive input from a torque output feature of a powertrain of the vehicle 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 epicyclic gear set
Implementation Method 2
a temperature sensor for generating output indicative of the temperature of fluid driven by the fluid pump
Implementation Method 3
a pump driver for driving a fluid pump
Data Source
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AI summary
Apparatus for managing fluid flow in a vehicle, comprising: an epicylic gear set (112) having first and second inputs configured to receive rotational drive input from a torque output feature of a powertrain and a rotary actuator (120; 220) respectively; a pump driver (110) for driving a fluid pump (108), the pump driver (110) configured to receive rotational drive input from an output of the epicylic gear set (112); a temperature sensor (111) for generating output indicative of the temperature of fluid driven by the fluid pump (108); and a controller (124) configured to receive the output generated by the temperature sensor (111) and based on this control the rotary actuator (120; 220) such that the pump driver (110) is caused to rotate at a speed such that the temperature of the fluid driven by the fluid pump (108) is substantially maintained in accordance with a prespecified condition.