Automatic Transmission Valve Actuation for Start-Stop Energy Savings
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Solution Overview
Problem
In automatic transmissions with a hydrodynamic torque converter, the hydraulic pressure supply drops when the engine is stopped, causing the transmission to shift to neutral, requiring time to rebuild pressure for starting, which increases energy consumption due to the need for a continuous power supply to maintain electrically controlled valves.
Innovation Solution
Applying electrical voltage to electrically controlled valves immediately after switching to the start phase, before hydraulic pressure build-up is complete, to engage a gear and fill the hydrodynamic torque converter with pressure medium, reducing energy consumption and quickening the start-up process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electrical voltage is continuously supplied to electrically controlled valves to maintain gear engagement during stop phase, then the transmission can quickly engage gear after restart, but electrical energy consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-positioning the transmission in neutral state during stop phase, and only activating the electrically controlled valves at the precise moment of restart initiation. This allows the system to be ready for immediate gear engagement without requiring continuous power supply to the valves during the stop phase, thus resolving the contradiction between quick start-up capability and electrical energy consumption.
2Stability of the object's composition
If hydraulic pressure is maintained in the hydraulic pressure supply during stop phase, then the transmission can maintain gear engagement, but the system requires continuous power consumption to build and maintain pressure
Solution Approach 1:
The patent extracts the hydraulic pressure maintenance function from the continuous operation mode and applies it only when needed during restart. By using electrically controlled valves that can rapidly engage gears once activated, the system eliminates the need for continuous hydraulic pressure maintenance during stop phase, thereby reducing power consumption while maintaining gear engagement stability when required.
3Loss of energy
If the transmission shifts to neutral position during stop phase due to pressure drop, then hydraulic pressure can be reduced, but the vehicle cannot start quickly as pressure must be rebuilt
Solution Approach 1:
The patent replaces the traditional hydraulic pressure-based gear engagement mechanism with an electrically controlled valve system. This substitution allows the transmission to use electrical signals to control valve positions, which then direct hydraulic pressure to engage gears. The electrically controlled valves can be activated instantly without waiting for pressure build-up, eliminating the time loss associated with hydraulic pressure reconstruction while minimizing hydraulic energy loss during stop phase.
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 method allows for quicker vehicle start-up and reduces electrical energy consumption by applying voltage to the valves before hydraulic pressure is fully built, optimizing the start-stop function in automatic transmissions.
Implementation Method 1
direct-actuated valves are provided whose magnetic force of the electromagnet is used directly to open or close the valve
Implementation Method 2
hydraulic or hydrodynamic components, which are supplied with a pressure medium, in particular oil, from a hydraulic pressure supply of the hydraulic system of the transmission and pressurized to bring about the shifting of the respective desired gear ratio
Implementation Method 3
the frictional connection in the transmission via the individual shifting elements cannot be maintained
Data Source
Figure 1
AI summary
The invention relates to a method for actuating an automatic transmission or automated manual transmission in a start-stop mode of a motor vehicle, wherein the transmission which is driven by an internal combustion engine of the motor vehicle comprises a hydraulic system with a hydraulic pressure supply and electrically controlled valves as well as a multiplicity of switching elements which, by having pressure applied to them with a pressure medium from the hydraulic pressure supply and through actuation of the valves, are switched in order to set various gears in the transmission. The valve device according to the invention is characterized in that when switching into a stop phase occurs, during which the internal combustion engine is switched off, a multiplicity or all of the electrically controlled valves are switched to a currentless state, and when switching into a start phase occurs or immediately after switching into a start phase, during which the internal combustion engine is switched on, an electric voltage is applied to the electrically controlled valves in order to engage a gear for the purpose of starting the vehicle.