Multi-pressure hydraulic supply system for automatic transmission
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Solution Overview
Problem
Automatic transmissions rely on a hydraulic pump that acts as a parasitic load on the vehicle engine, which negatively impacts vehicle mileage, as existing systems do not efficiently manage pressurized fluid distribution to minimize this load.
Innovation Solution
A hydraulic system with a pump having both low and high pressure outlets, connected via a directional valve that dynamically routes pressurized fluid to either high or low pressure components based on engine speed and operational needs, utilizing a pressure regulator valve to control flow and minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic pump is used to provide pressurized fluid to the transmission, then the transmission can operate reliably, but the pump creates a parasitic load on the vehicle engine that reduces fuel efficiency
Solution Approach 1:
The hydraulic pump is segmented into two independent outlets: a high-pressure outlet (first outlet) and a low-pressure outlet (second outlet). This allows the system to separately manage high-pressure fluid delivery for transmission operation and low-pressure fluid delivery for cooling and lubrication, enabling the pump to be disengaged or operated at reduced load when only low-pressure functions are needed, thereby reducing parasitic load on the engine.
Solution Approach 2:
The system dynamically switches between different operational modes using a directional valve that can route fluid from either the high-pressure outlet or the low-pressure outlet to various transmission components. This dynamic routing allows the system to adapt to varying operational requirements, engaging the pump only when necessary and selecting the appropriate pressure level, thus minimizing continuous parasitic load on the engine.
2Reliability
If the hydraulic pump operates continuously to ensure transmission reliability, then the transmission functions properly, but power consumption increases and vehicle mileage decreases
Solution Approach 1:
The pump operation is made periodic rather than continuous. The control system activates the pump only when pressurized fluid is actually needed for transmission operation, allowing the pump to remain stationary during periods when the transmission does not require pressurized fluid. This periodic operation significantly reduces power consumption and energy loss while maintaining transmission reliability when needed.
Solution Approach 2:
Different pressure levels are provided locally to different transmission components based on their specific needs. The high-pressure outlet serves components requiring high pressure (such as clutch actuators and gear shift mechanisms), while the low-pressure outlet serves components requiring lower pressure (such as cooling and lubrication systems). This localized pressure delivery ensures reliable transmission function while minimizing the energy required to drive the pump.
3Device complexity
If a single-pressure hydraulic system is used, then the system is simple, but it cannot efficiently minimize parasitic load during low engine speeds
Solution Approach 1:
The hydraulic system is segmented into two pressure circuits with separate outlets and control pathways. This segmentation allows the system to select between high-pressure and low-pressure modes of operation, enabling efficient minimization of parasitic load during low engine speeds by operating in low-pressure mode when full power is not required, while maintaining the capability for high-pressure operation when needed.
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 optimizes pressurized fluid distribution, reducing parasitic load on the engine by recycling low-pressure fluid back to the pump inlet during low engine speeds, thereby minimizing power consumption and improving vehicle mileage.
Implementation Method 1
a first hydraulic line connects the first outlet with a first hydraulic component; a second hydraulic line connects the second outlet with a second hydraulic component
Implementation Method 2
a pressurized fluid source provided by a balanced vane pump (10)
Data Source
AI summary
A pressurized fluid supply system for a vehicle transmission is provided. The fluid supply system has a pump with at least high and low pressure outputs that supplies high and low pressure components via a directional valve. The pressurized fluid supply system minimizes the parasitic loss upon a vehicle engine.