All-Wheel Drive Disconnect Clutch Presynchronization Control
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Solution Overview
Problem
Existing all-wheel drive systems for motor vehicles experience prolonged and unnecessary coupling operations, leading to excessive stress on vehicle components and reduced driving comfort due to delayed switching into all-wheel drive mode.
Innovation Solution
A method for controlling all-wheel drive vehicles that determines an all-wheel requirement using input signals and prepares the secondary drive axle for connection without closing the disconnect clutch, allowing for rapid and reduced frequency of coupling operations, thereby reducing wear on components and enhancing driving comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the disconnect clutch is closed immediately when all-wheel drive is required, then the switching response is fast, but the coupling operation lasts too long and causes excessive stress on vehicle components
Solution Approach 1:
The patent applies preliminary action by presynchronizing the torque transmission train with the primary drive axle before actually closing the disconnect clutch. When the control unit predicts an upcoming all-wheel drive requirement based on input signals, it initiates synchronization of the secondary drive axle in advance, so that when the clutch finally closes, the coupling operation is completed much faster and with reduced stress on components.
2Speed
If the disconnect clutch is closed immediately when all-wheel drive is required, then the switching response is fast, but driving comfort is reduced due to delayed switching
Solution Approach 1:
The control unit performs preliminary synchronization of the torque transmission train before the actual clutch engagement. This advance preparation eliminates time delays during the switching process, ensuring smooth and rapid transition to all-wheel drive mode, thereby maintaining driving comfort while achieving fast response.
3Adaptability or versatility
If coupling operations are carried out frequently, then the all-wheel drive system responds to various driving conditions, but vehicle components experience excessive wear
Solution Approach 1:
By presynchronizing the torque transmission train in advance when all-wheel drive is anticipated, the system reduces the duration and intensity of coupling operations. This minimizes mechanical stress and wear on the disconnect clutch and torque transmission train components, while still maintaining the ability to respond adaptively to various driving conditions.
Data Source
AI summary
A method for controlling a motor vehicle (1) operated in all-wheel drive at times, by means of a control unit (3), wherein the motor vehicle comprises a drive unit (11), a primary drive axle (14) permanently driven by the drive unit (11), a secondary drive axle (24), a torque transmission train (17, 17.1) for transmitting the torque of the drive unit (11) to the secondary drive axle (24), and a disconnect clutch (15) for coupling the secondary drive axle (24) to and uncoupling same from the drive unit (11), wherein the control unit (3) can actuate the disconnect clutch (15) via a first actuating unit (16), characterized by the following stepsdetermining an all-wheel requirement for the motor vehicle from input signalsif there is a predetermined all-wheel requirement, preparing an all-wheel operation, wherein the disconnect clutch (15) is not closed.