Dual Element Pump Hydraulic Control System for Transmission
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Solution Overview
Problem
Conventional hydraulic control systems for automatic transmissions have complex components and inefficiencies in fluid distribution, leading to suboptimal controllability and energy usage.
Innovation Solution
A dual element pump system with separate high and low pressure outlets, driven by an electric motor, and a diversion valve that adjusts fluid flow to prioritize high pressure for torque transmitting devices and low pressure for cooling and lubrication, minimizing component complexity and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional main pump is used to provide pressurized hydraulic fluid to all circuits, then the system structure is simple, but the system cannot efficiently meet different pressure and flow demands of various subsystems leading to energy loss
Solution Approach 1:
The single main pump is segmented into two separate pumps: a high-pressure pump for torque transmitting devices and a low-pressure pump for cooling and lubrication circuits. This segmentation allows each pump to be optimized for its specific pressure requirements, eliminating energy loss from over-pressurization in low-pressure circuits while maintaining simple overall system architecture.
2Device complexity
If a single pump supplies all hydraulic circuits, then the component count is low, but the controllability of fluid distribution to different circuits is poor
Solution Approach 1:
By segmenting the pump system into two independent pumps with separate outlets, the system gains independent controllability over high-pressure and low-pressure circuits. Each pump can be controlled separately to meet the specific demands of different subsystems, significantly improving fluid distribution controllability without adding complex control mechanisms.
3Reliability
If hydraulic fluid is provided to torque transmitting devices with rotating seal rings, then the devices can be actuated, but fluid leakage occurs reducing system efficiency
Solution Approach 1:
The system incorporates pressure sensors in both high-pressure and low-pressure circuits that provide feedback to the control unit. This feedback enables the control unit to monitor actual pressure conditions and adjust pump operation accordingly, maintaining reliable actuation of torque transmitting devices while minimizing fluid leakage through optimized pressure control.
4Device complexity
If the main pump is engine-driven, then the pump operation is simple, but the system efficiency is reduced due to continuous operation regardless of actual hydraulic demand
Solution Approach 1:
The engine-driven mechanical pump system is replaced with an electrically-driven pump system. The electric motor can be precisely controlled by the control unit based on actual hydraulic circuit demands, allowing the pump to operate only when needed and at optimal speeds, significantly reducing energy consumption while maintaining simple drive mechanism operation.
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 reduces hydraulic losses, improving fuel economy by 0.5 miles per gallon and saving 50 watts of electrical energy, while maintaining effective actuation of torque transmitting devices.
Implementation Method 1
The dual element pump provides a first volume of hydraulic fluid to a first outlet port and provides a second volume of hydraulic fluid to a second outlet port. The first volume is greater than the second volume and the first outlet port is at a lower pressure than the second outlet port.
Implementation Method 2
The diversion valve has an inlet port in communication with the first outlet port of the dual element pump, a first outlet port in communication with the low pressure hydraulic circuit, and a second outlet port in communication with the high pressure hydraulic circuit. The diversion valve is moveable between at least two positions
Implementation Method 3
A dual element pump system with separate high and low pressure outlets, driven by an electric motor
Data Source
AI summary
A hydraulic control system for a transmission includes a motor, a sump for storing a hydraulic fluid, and a dual element pump connected to the motor. The dual element pump has at least one input port connected to the sump, a first outlet port, and a second outlet port. The dual element pump provides a first volume of hydraulic fluid to the first outlet port and provides a second volume of hydraulic fluid to the second outlet port. The first volume is greater than the second volume. The first outlet port is connected to a diversion valve. The second outlet port is connected to a high pressure hydraulic circuit. The diversion valve is operable to transmit the hydraulic fluid from the first outlet port to a low pressure hydraulic circuit and the high pressure hydraulic circuit.