Double-Clutch Hydraulic Circuit With Bypass Relief for Emergency Torque Cutoff
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dual clutch transmissions face challenges in achieving reliable and safe clutch control, particularly in emergency situations, due to uncontrolled torque flows and partial system failures, which existing hydraulic circuits are unable to adequately address.
Innovation Solution
A hydraulic circuit design with independent clutch branches, each equipped with a proportional pressure control valve, check valves, and bypass lines, allowing for controlled clutch actuation and rapid power flow interruption, ensuring safety and functionality even in faulty conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common hydraulic circuit is used for both clutches, then the device complexity is reduced, but uncontrolled torque flows and safety risks increase during emergencies
Solution Approach 1:
The hydraulic circuit is divided into two independent branches: a first hydraulic branch for the first clutch and a second hydraulic branch for the second clutch. Each branch has its own proportional pressure control valve, check valve, and bypass line, ensuring that failures in one branch do not affect the other and preventing uncontrolled torque flows during emergencies.
2Device complexity
If pressure control valves are placed in series without bypass lines, then the device complexity is reduced, but the ability to rapidly interrupt power flow in emergencies is lost
Solution Approach 1:
Bypass lines with check valves are pre-configured in parallel with each pressure control valve. In normal operation, the bypass lines are blocked by the check valves. In emergency situations, the check valves automatically open to allow rapid pressure relief and power flow interruption without requiring active valve actuation.
3Reliability
If a single hydraulic branch controls one clutch, then the reliability for that clutch is improved, but the device complexity increases due to additional components
Solution Approach 1:
Each hydraulic branch is equipped with locally optimized components: a proportional pressure control valve for precise clutch actuation, a check valve for automatic bypass control, and a bypass line for emergency pressure relief. This localized configuration ensures high reliability for each clutch while maintaining overall system manageability through modular design.
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 proposed hydraulic circuit enables rapid and controlled power flow interruption, maintaining transmission safety and functionality during emergencies, and ensures continued operation even if individual components fail, meeting high ASIL levels.
Implementation Method 1
A first proportional pressure control valve (51) is located in the line leading to the first clutch actuator (57). A second proportional pressure control valve (53) is located in the line leading to the second clutch actuator (59).
Implementation Method 2
The at least one check valve (83) is located upstream of the downstream pressure control valve (51, 53) when viewed from the hydraulic source (15).
Implementation Method 3
Each of the at least two pressure regulating valves (51, 53) is located in an independent hydraulic branch (65), the so-called coupling branch. At least two of the hydraulic branches (65) terminate in their respective actuators (57, 59).
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a hydraulic circuit which is part of a double clutch transmission, in particular as a passenger motor vehicle double clutch transmission, by way of which hydraulic circuit clutch actuators can be actuated. Furthermore, the present invention relates to a method concerning how controlled states of the transmission can be achieved in emergency situations of a double clutch transmission. It is particularly advantageous if each of the clutches can be actuated in a dedicated hydraulic branch via a pressure regulation operation. It is possible in an embodiment of this type that the degree of actuation of the controlled clutch corresponds to a pressure which prevails in the clutch actuating means, the clutch actuator. At least one bypass line belongs to each hydraulic branch. Ideally, the first hydraulic branch has a first bypass line and the second hydraulic branch has a second bypass line. The respective bypass line leads in sections parallel to a main line of the hydraulic branch. A flow regulation valve is integrated into at least one of the bypass lines.