Dual-Clutch Transmission Locking for Standstill Without Heat Loss
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Solution Overview
Problem
Dual clutch transmissions in work vehicles dissipate excessive energy when maintaining a standstill, leading to inefficiency and increased heat loss, as both clutches must remain slipping to prevent engine stall, which is not sustainable for prolonged operations.
Innovation Solution
A method that modulates the forward and rearward clutches to lock the transmission by engaging the even and odd clutches, creating a mechanical short circuit to block the intermediate geared shaft and output shaft, allowing the vehicle to be decoupled from the engine, thereby preventing unnecessary energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both forward and rearward clutches are maintained slipping to prevent engine stall when vehicle is at standstill, then engine stall is prevented, but excessive energy is dissipated as heat
Solution Approach 1:
The invention segments the clutch control into distinct states: a first state where both clutches are slipping to prevent engine stall, and a second state where both clutches are locked to prevent energy dissipation. The control system transitions between these segmented states based on vehicle speed thresholds, allowing optimal performance in each operating condition.
Solution Approach 2:
The invention dynamically adjusts clutch operation based on real-time vehicle speed. When vehicle speed exceeds the first threshold, the system transitions from the locking state to the slipping state. When vehicle speed falls below the second threshold, it transitions from slipping to locking. This dynamic adaptation resolves the contradiction by matching clutch behavior to actual operational needs.
2Stability of the object's composition
If clutches are maintained slipping to keep vehicle at standstill, then vehicle positioning is maintained, but heat generation increases
Solution Approach 1:
The control system segments clutch operation into distinct thermal management states. Below the second speed threshold, clutches are locked to minimize heat generation. Above the first threshold, clutches slip to maintain positioning. This segmentation allows the system to manage thermal load effectively while maintaining vehicle stability.
Solution Approach 2:
The system employs periodic monitoring of vehicle speed against predefined thresholds and alternates between slipping and locking states accordingly. This periodic action between the two clutch states allows the system to maintain vehicle positioning when needed while minimizing heat generation during extended standstill periods.
3Loss of energy
If clutches are locked to prevent energy dissipation, then energy efficiency is improved, but engine stall may occur
Solution Approach 1:
The control system continuously monitors vehicle speed and provides feedback to adjust clutch operation. When speed exceeds the first threshold, feedback triggers transition to slipping mode to prevent engine stall. When speed drops below the second threshold, feedback triggers transition to locking mode for energy efficiency. This closed-loop feedback resolves the contradiction by adapting clutch state to real-time conditions.
Solution Approach 2:
The system establishes predefined speed thresholds that trigger clutch state transitions in advance. The first threshold preliminarily signals when to transition from locking to slipping mode, while the second threshold preliminarily signals when to transition from slipping to locking mode. This preliminary action prevents engine stall before it can occur while maximizing energy efficiency.
4Speed
If service brakes are used for deceleration, then vehicle speed is reduced, but braking distance and wear increase
Solution Approach 1:
The invention merges engine braking through clutch slipping with service brake operation. During deceleration, the control system engages clutch slipping to provide engine braking torque, which works in combination with service brakes. This merging reduces the duration and intensity of service brake application, thereby reducing wear and braking distance while achieving the required deceleration.
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 the vehicle to be maintained in a locked state without energy wastage, reducing fuel consumption and enabling the vehicle to be stopped on slopes, with the transmission remaining firmly blocked for extended periods.
Implementation Method 1
engaging the even and odd clutches, creating a mechanical short circuit to block the intermediate geared shaft and output shaft
Implementation Method 2
both clutches must be maintained slipping in order to prevent the stall of the engine. In this way clutches dissipate a lot of energy in heat
Data Source
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AI summary
Method and system for locking a dual clutch transmission (1) of a work vehicle which is in movement, said method essentially comprising the phases of: • Use the rearward clutch (6) of the dual clutch transmission (1) to brake the vehicle until a preset value of velocity; • Select a blocking gear between the speed ratio gears (14, 15); and • Produce a mechanical short-circuit between the even and odd shafts (11, 12) of the dual clutch transmission (1) in order to block the transmission (1); and • Decouple the engine input shaft (2) from transmission (1) by disengaging the forward and rearward clutches (5, 6).