Parallel Shifting Transmission Clutch Control for Fault Tolerant Drivability
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Solution Overview
Problem
Existing methods for controlling parallel shifting transmissions fail to maintain drivability when a malfunction occurs in the clutch actuating device, leading to coarse gear step intervals and loss of shifting capability in case of total faults.
Innovation Solution
A method and device that allow seamless gear ratio changes between subtransmissions without traction interruption by disengaging one clutch and engaging the other, ensuring the previously engaged clutch is disengaged and no gear is selected in its subtransmission, using sensors and an electronic control device to manage clutch actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the previously engaged clutch is re-engaged immediately after malfunction detection, then drivability is maintained, but dangerous states may occur and traction interruption cannot be avoided
Solution Approach 1:
The control device checks whether the previously engaged clutch is already disengaged or whether no gear is selected in the associated subtransmission before allowing re-engagement. This preliminary verification prevents dangerous operating states by ensuring the clutch engagement conditions are safe before permitting the engagement action to occur.
2Ease of operation
If seamless gear ratio changes are implemented without traction interruption, then drivability is improved, but the system becomes vulnerable to malfunctions in clutch actuating devices
Solution Approach 1:
The control device continuously monitors the operational status of clutch actuators and receives malfunction signals from the clutch actuating devices. This feedback mechanism enables the system to detect malfunctions early and switch to alternative operating modes that maintain drivability while avoiding dangerous states, thus improving reliability without sacrificing ease of operation.
3Productivity
If the clutch is disengaged and re-engaged rapidly to maintain continuous operation, then productivity is maintained, but traction interruption occurs and system reliability decreases
Solution Approach 1:
Before re-engaging a clutch after malfunction, the control device performs preliminary checks to verify that the clutch is already disengaged or that no gear is selected in the associated subtransmission. This prevents rapid disengagement-reengagement cycles that would cause traction interruption and maintains system reliability while allowing continuous operation when safe conditions are met.
Data Source
AI summary
A method for controlling operation of a parallel transmission comprising two partial transmissions that act upon a common drive shaft and can be coupled to a drive shaft via one respective clutch. The gear ratio of the parallel transmission can be changed from the gear that is engaged in one partial transmission to the gear that is engaged in the other partial transmission without interrupting traction when the parallel transmission functions correctly by opening the clutch of one partial transmission and simultaneously closing the clutch of the other partial transmission. When a malfunction is detected in the actuator of at least one of the clutches, the open clutch can be closed only if at least one of the following conditions is met: the previously closed clutch is open; or, no gear is engaged in the partial transmission allocated to the previously closed clutch.