AMT Gear Shift Torque Fill Using a Primary-Shaft Electric Machine
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Solution Overview
Problem
Automated manual transmissions (AMT) and manual transmissions (MT) suffer from a torque gap during gear changes, causing noticeable deceleration perceived by drivers and passengers, which existing solutions fail to adequately address without increasing fuel consumption or complexity.
Innovation Solution
Incorporating an electric machine connected to the primary shaft of the transmission, which provides supplementary torque during gear changes to counteract deceleration forces, thereby reducing the torque gap and improving the driving experience by synchronizing engine and electric motor actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an automated manual transmission (AMT) is used to reduce fuel consumption and CO2 emissions, then fuel efficiency is improved, but a noticeable torque gap and deceleration are perceived during gear changes
Solution Approach 1:
An electric machine is introduced as an intermediary component between the engine and the drive wheels. During gear change phases when the clutch disconnects the engine from the transmission, the electric machine acts as a mediator to provide supplementary torque to the drive wheels, compensating for the torque gap and eliminating the perceived deceleration while maintaining the fuel efficiency benefits of AMT
2Ease of operation
If the gear change time is reduced to eliminate torque gap perception, then driving comfort is improved, but the complexity of the transmission system increases
Solution Approach 1:
The system changes the torque parameter dynamically during gear transitions. By controlling the electric machine to provide supplementary torque specifically during the disengagement phase, the system maintains driving comfort without requiring a complete redesign of the transmission architecture, thus avoiding excessive complexity while achieving seamless gear changes
3Ease of operation
If an electric machine is added to compensate for torque gap, then driving comfort is improved, but the cost and complexity of the transmission system increase
Solution Approach 1:
The electric machine is designed with multi-functionality: it serves both as a torque compensator during gear changes and as a hybrid propulsion component for reducing fuel consumption and CO2 emissions. This universal application justifies the added complexity by delivering multiple benefits from a single component addition
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 solution eliminates the perception of torque reversal during gear changes, making the AMT equivalent to automatic or dual-clutch transmissions in terms of driving sensation, while maintaining low fuel consumption and costs, and enabling the transformation of internal combustion engine vehicles into hybrid electric vehicles with reduced CO2 emissions.
Implementation Method 1
incorporating an electric machine connected to the primary shaft of the transmission, which provides supplementary torque during gear changes
Data Source
Figure 1
Figure 2a~2c
AI summary
A management and control method of the gear change phases of a vehicle fitted with a manual or automated manual transmission (16), comprising the steps of: - providing a vehicle having an endothermic engine (8) with relative crankshaft (26), and a manual or automated manual transmission (16) having a clutch, a primary shaft (28) operatively connected to the clutch (24), and a secondary shaft (32) operatively connected to the drive wheels (36) of the vehicle, wherein the primary and secondary shafts (28, 32) are provided with gears (40) meshing with each other in a plurality of gears, wherein the gear change comprises a first step of opening or disengaging the clutch (24) so as to disconnect the engine (8) from the primary shaft (28), a second step of engaging a new gear, keeping the clutch (24) disengaged, a third step of engaging the clutch (24) to reconnect the crankshaft (26) with the primary shaft (28) of the manual or automated manual transmission (16). Advantageously, the steps of preparing an electric machine (44) operatively connected to the primary shaft (28) by transmission means(48), said electric machine (44) being mechanically separate from the engine (8), and the actuation of the electric machine (44) during at least one of said gear change steps so as to supply torque to the secondary shaft (32) via the primary shaft (28) to counteract the reduction in speed of progress of the vehicle during said gear change, are provided for.