Shift System Pressure Control via Pre-Fill Valve
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Solution Overview
Problem
Automatic or automated shifting systems face challenges in maintaining constant air pressure during gear shifts due to pressure drops in the shift cylinders, which conventional regulators fail to address effectively, leading to inefficiencies and potential overpressure issues.
Innovation Solution
The method determines the precise pressure medium requirement for each shifting process and pre-fills the air storage space before shifting begins by calculating and controlling the main shut-off valves based on stored data, allowing for precise pressure management and avoiding pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional pressure regulators are used to maintain constant pressure during shifting, then pressure stability is improved, but the response time is too slow to compensate for rapid pressure drops at the beginning of shifting
Solution Approach 1:
The control unit calculates and opens the main shut-off valve before the shifting operation begins, pre-filling the air reservoir with pressure medium. This preliminary action ensures that when the shift cylinder volume increases during shifting, the pressure drop is immediately compensated without waiting for the pressure regulator to react, thus maintaining both pressure stability and fast response.
2Speed
If high throughput valves with short response time are used to compensate for pressure drops, then response speed is improved, but the setpoint pressure may be exceeded causing overpressure
Solution Approach 1:
The control unit continuously monitors the actual pressure in the air reservoir and uses this feedback information to control the opening duration of the main shut-off valve. By comparing the actual pressure with the target pressure, the control unit adjusts the valve opening time to precisely match the pressure medium requirement, ensuring fast response without exceeding the setpoint pressure.
Solution Approach 2:
The system dynamically adjusts the main shut-off valve opening duration based on real-time pressure conditions and shifting requirements. Rather than using a fixed valve opening strategy, the control unit calculates the optimal opening time considering the current pressure state, shifting phase, and volume changes, enabling precise pressure control during dynamic shifting operations.
3Stress or pressure
If pressure solenoid valves are used to control pressure during shifting, then pressure control precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention replaces complex pressure solenoid valves with a combination of a simple 2/2-way main shut-off valve and a control unit that calculates and controls the valve opening duration. This substitution uses electronic control and calculation algorithms to achieve precise pressure control without the mechanical complexity and high cost of pressure solenoid valves, while maintaining the ability to precisely control pressure during shifting operations.
4Speed
If the air space in the shift cylinder is small, then shifting speed is improved, but pressure drops more significantly during the first actuation
Solution Approach 1:
The control unit calculates the pressure medium requirement based on the small air space volume and opens the main shut-off valve beforehand to pre-fill the air reservoir. This preliminary action compensates for the significant pressure drop that occurs when the small volume is rapidly expanded during the first actuation, ensuring that pressure is maintained despite the fast shifting speed enabled by the small air space.
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 approach ensures that pressure remains constant during shifting, reducing the risk of overpressure and enabling efficient gear changes, even with inexpensive 2/2-way valves, by pre-filling the air storage space before piston movement, thus enhancing control and reducing the need for complex and costly pressure solenoid valves.
Implementation Method 1
the pressure medium requirement for shift processes to be carried out is determined and the respective main shut-off valves are controlled in dependence thereon
Data Source
AI summary
The invention relates to a method for controlling an automatic or automated shift system, for example for shifting a multi-step transmission, having a control unit (22), one or more shift cylinders (10, 12) which can be activated by pressure medium by means of assigned shift valves (14, 16, 18, 20), and at least one main shift valve (4, 6) which is arranged upstream of the shift valves, wherein the demand for pressure medium for shift processes to be carried out is determined and the respective main deactivation valves (4, 6) are actuated as a function thereof. According to the invention, pressure medium demand values are stored for all conceivable shift scenarios or shift times derived therefrom for the main deactivation valves (4, 6) in the control unit (22). When a shift command is initiated, they are retrieved and the shift system is already sufficiently filled by opening the main deactivation valves (4, 6) before a dip in pressure, in order to ensure the necessary pressure in the shift cylinders (10, 12).