Hydraulic Pressure Supply System for Automatic Transmission
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Solution Overview
Problem
Conventional hydraulic pressure systems in automatic transmissions experience unnecessary power loss and reduced fuel efficiency due to uncontrollable oil supply and generation of high hydraulic pressure at high RPM, leading to inefficient power transmission.
Innovation Solution
A hydraulic pressure supply system that includes a mechanical oil pump and an electrical oil pump, with switch valves and solenoid valve actuators to control oil flow and operation modes, allowing for optimized fuel efficiency by minimizing mechanical pump capacity and utilizing the electrical pump as a main driver in key areas, while providing a recirculation path and check valve for stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a mechanical oil pump is used to supply hydraulic pressure to the automatic transmission, then the system can provide continuous hydraulic pressure, but unnecessary power loss occurs and fuel efficiency deteriorates due to uncontrollable oil supply and high hydraulic pressure generation at high RPM
Solution Approach 1:
The patent divides the single mechanical pump system into two separate pumps: a mechanical oil pump and an electrical oil pump. This segmentation allows each pump to operate independently based on specific driving conditions, enabling the mechanical pump to be downsized and operate only when necessary, thereby reducing unnecessary power loss and improving fuel efficiency.
Solution Approach 2:
The system dynamically switches between different pump operation modes (first operation mode with both pumps operating, second operation mode with only electrical pump operating, third operation mode with only mechanical pump operating) based on driving conditions such as vehicle speed and engine RPM. This dynamic adaptation eliminates unnecessary power consumption by the mechanical pump at high RPM while maintaining required hydraulic pressure.
2Loss of energy
If the mechanical oil pump capacity is reduced to improve fuel efficiency, then power loss decreases, but the system may fail to provide sufficient hydraulic pressure under certain driving conditions
Solution Approach 1:
The electrical oil pump acts as an intermediary that supplements the downsized mechanical pump. When the mechanical pump alone cannot provide sufficient hydraulic pressure, the electrical pump activates to make up the difference, ensuring reliable hydraulic pressure delivery while allowing the mechanical pump to operate at reduced capacity for improved fuel efficiency.
Solution Approach 2:
The system changes operational parameters by switching between different pump combinations based on driving conditions. The control unit monitors vehicle speed, engine RPM, and hydraulic pressure requirements to determine when to activate each pump, thereby maintaining reliable hydraulic pressure while optimizing power loss across varying operating conditions.
3Productivity
If switch valves and solenoid valve actuators are added to control oil flow and operation modes, then fuel efficiency is optimized through minimized mechanical pump capacity, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical flow control mechanisms with electronically controlled solenoid valves and switch valves. This substitution allows for precise control of oil flow and pump operation modes through electrical signals, simplifying the control architecture while enabling optimized fuel efficiency through minimized mechanical pump capacity operation.
4Stability of the object's composition
If a recirculation path is implemented to ensure hydraulic pressure stability, then pressure control is improved, but system complexity increases
Solution Approach 1:
The recirculation path merges the discharge line back to the suction line, creating a closed-loop system that stabilizes hydraulic pressure by allowing excess oil to recirculate rather than being wasted. This integration of the recirculation function into the existing pump system provides pressure stability while minimizing additional system complexity.
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 achieves maximum fuel efficiency by realizing five operation modes based on driving conditions, minimizing mechanical pump capacity, ensuring hydraulic pressure stability, and enhancing system reliability with a fail-safe function, even during electrical pump malfunctions.
Implementation Method 1
a mechanical oil pump fluidly-connected to the oil pan and driven by an engine to pump the oil stored in the oil pan as a first high-pressure hydraulic pressure
Implementation Method 2
an electrical oil pump fluidly-connected to the oil pan and driven by an electrical motor to pump the oil stored in the oil pan as a second high-pressure hydraulic pressure
Implementation Method 3
A check valve preventing back flow is provided on the third supply path
Data Source
AI summary
A hydraulic pressure supply system of an automatic transmission may include a mechanical oil pump fluidly-connected to the oil pan to supply oil to first and second discharge paths fluidly-connected to the mechanical oil pump, a first switch valve fluidly-connected to the first discharge path and selectively supplying oil to a first supply path fluidly-connected to the first switch valve, a second switch valve fluidly-connected to the first and second discharge paths and selectively supplying oil supplied in the first supply path to the transmission unit and a pressure control valve through a second supply path fluidly-connected to the second switch valve, respectively, a first solenoid valve actuator engaged to the first switch valve and a second solenoid valve actuator engaged to the second switch valve, and an electrical oil pump fluidly-connected to the oil pan to supply the oil to a third supply path fluidly-connected with the second supply path.