Dual Clutch Transmission Emergency Safety Control
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Solution Overview
Problem
Existing monitoring concepts for vehicle control units, such as the 3-level EGAS concept, are not applicable to mechanically non-intrinsically safe systems like hydraulically or electromechanically actuated dual clutch transmissions, particularly those with 'normally closed' clutches, as they rely on mechanical spring forces and lack intrinsic safety mechanisms.
Innovation Solution
A device and method for controlling dual clutch transmissions that include a main computer, a monitoring unit, and a separate hardware unit to manage clutch actuation using residual energy stored in hydraulic or electrical accumulators, with mechanical locking devices to maintain the open state without additional energy expenditure, allowing for safe operation in emergency conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-level monitoring concept (EGAS concept) is used for control units, then reliability and availability are improved, but it cannot be applied to mechanically non-intrinsically safe systems like dual-clutch transmissions with normally closed clutches
Solution Approach 1:
The control system is divided into functionally independent parts: a main computer for normal control operations, a separate hardware unit for emergency clutch actuation, and a monitoring unit for safety supervision. This segmentation allows the system to maintain reliability through monitoring while adapting to mechanically non-intrinsically safe clutch designs by isolating the emergency function in a dedicated hardware component.
Solution Approach 2:
A separate hardware unit acts as an intermediary between the main computer and the clutch actuator in emergency situations. This intermediary component receives commands from the main computer and directly actuates the clutch using stored residual energy, bypassing the need for continuous active control and enabling safe operation of mechanically non-intrinsically safe systems.
2Use of energy by moving object
If residual energy is used to maintain the open clutch state, then energy consumption is reduced, but the system requires mechanical locking devices and separate hardware units
Solution Approach 1:
Energy is stored in advance in hydraulic or electrical accumulators during normal operation. When an emergency situation occurs, this pre-stored residual energy is immediately available to actuate the clutch open without requiring additional energy input during the critical safety event, thereby reducing real-time energy consumption while accepting the need for preliminary energy storage infrastructure.
Solution Approach 2:
The active control function is extracted from the emergency safety mechanism. Instead of relying on continuous active control to maintain clutch position, the system uses passive mechanical locking devices combined with residual energy storage. This extraction of the active control element simplifies the emergency response mechanism while accepting increased structural complexity in the form of separate hardware units and mechanical locks.
3Reliability
If a separate hardware unit is used for emergency clutch actuation, then safety is improved, but device complexity increases
Solution Approach 1:
The separate hardware unit is designed to be self-contained and self-actuating. It includes its own energy storage (hydraulic or electrical accumulators), control logic, and actuation mechanism that can independently open the clutch in emergency situations without requiring external power or control signals during the critical safety event. This self-service capability improves emergency safety while minimizing the complexity of external control systems.
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
Enables safe operation of mechanically non-intrinsically safe dual clutch transmissions by utilizing stored residual energy to maintain an open drive train state, eliminating the need for active control systems and enabling the use of 'normally closed' clutches in automated transmissions.
Implementation Method 1
The residual hydraulic energy is stored, in particular, as residual pressure in a hydraulic pressure accumulator of the device
Implementation Method 2
The hydraulic clutch actuator (KAH1, KAH2) is held in the open position by means of a mechanical locking device (VVR) when the at least one hydraulic clutch (KH1, KH2)
Implementation Method 3
at least one of the hydraulic clutches is closed by spring force in the unpressurized state
Data Source
Figure 1
Figure 2a~2c
AI summary
A device and method for regulating a double-clutch transmission activated hydraulically or electromechanically in a motor vehicle, wherein the device comprises a main computer (μC) which in an emergency operating mode can actuate a separate hardware unit (HWE), a monitoring unit (WD) for monitoring the main computer (μC), wherein the monitoring unit (WD) can also actuate the separate hardware unit (HWE) in the emergency operating mode, hydraulic clutches (KH1, KH2) for a first or second component transmission, wherein at least one clutch (KH1, KH2) is closed in the pressureless state by spring force, a control unit (SE1, SE2) for controlling a clutch actuator (KAH1, KAE1, KAH2, KAE2) for activating the clutch (KH1, KE1, KH2, KE2) and/or for controlling a transmission actuator (GAH, GAE) in order to bring about the various driving positions of the double-clutch transmission. In the case of a fault, the safe state of an open drive train can be brought about by means of the separate hardware unit (HWE) by the latter driving the clutch actuator (KAH1, KAE1, KAH2, KAE2) by means of the first control unit (SE1) and said clutch actuator opening the at least one normally closed clutch (KH1, KH2), or by said hardware unit (HWE) actuating the hydraulic transmission actuator (GAH) by means of the second control unit (SE2) and said transmission actuator (GAH) placing the double-clutch transmission in the neutral position, wherein the state of the open drive train can be brought about by using residual hydraulic and/or electrical energy which is stored in the device, and wherein this state can be maintained without the consumption of additional energy, until the emergency operating mode is cancelled.