Gear Shift Coordination in Multi-Axle Drive Arrangements
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle drive systems with multiple gear boxes connected to drive axles face challenges in smooth gear shifting, particularly during high propulsive torque applications, leading to power or acceleration interrupts, which affect performance, comfort, and driveability.
Innovation Solution
A drive arrangement with at least one electronic control unit that automatically shifts gears simultaneously or sequentially on multiple gear boxes, allowing for versatile gear shifting modes based on prevailing conditions detected by sensors, such as tire friction, vehicle speed, and propulsive torque, to enhance comfort and dynamic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gear shifting is performed sequentially on multiple drive axles, then vehicle comfort is improved by reducing power interrupts, but gear shifting time and complexity increase
Solution Approach 1:
The gear shifting process is segmented into sequential operations across multiple drive axles. The control system divides the overall gear change into individual axle-level shifts, executing them one after another rather than simultaneously. This segmentation allows each axle to complete its gear change independently, reducing power transmission interrupts while managing the complexity of coordinating multiple axles.
Solution Approach 2:
The control system performs preliminary synchronization of rotational speeds before executing gear changes. By pre-coordinating the rotational states of different drive axles, the system prepares the mechanical conditions necessary for smooth sequential shifting. This preliminary action ensures that when each axle shifts gear, the power flow can be maintained with minimal interruption to the overall vehicle motion.
2Loss of time
If simultaneous gear shifting is performed on multiple gear boxes, then gear shifting time is reduced, but vehicle stability and comfort deteriorate due to increased power interrupts
Solution Approach 1:
Instead of executing gear changes simultaneously across all drive axles, the system segments the operation into sequential axle-level shifts. This segmentation prevents the mechanical conflicts and power transmission shocks that would occur with simultaneous shifting, thereby maintaining vehicle stability while still achieving relatively quick overall gear changes through efficient sequential coordination.
3Adaptability or versatility
If sequential gear shifting is implemented on multiple drive axles, then device complexity and control effort increase, but adaptability to different driving conditions improves
Solution Approach 1:
The control system dynamically adapts the gear shifting sequence based on real-time driving conditions. Rather than following a fixed predetermined sequence, the system monitors parameters such as road surface conditions, vehicle load, and propulsion requirements to optimize the timing and order of gear changes across different axles. This dynamic approach enhances adaptability while the underlying sequential framework manages control complexity.
Solution Approach 2:
The system employs feedback mechanisms to monitor driving conditions and adjust the gear shifting sequence accordingly. Sensors detect parameters such as wheel slip, road gradient, and vehicle speed, and this information feeds back to the control system to optimize the sequential gear change timing. This feedback loop enables the system to adapt to varying road conditions without requiring overly complex manual intervention.
Data Source
AI summary
The invention relates to a drive arrangement for a vehicle and a method for gear shifting in a vehicle. The drive arrangement (5) comprises at least a first drive axle (10, 20, 30) operatively connected to a first gear box (11) and a first propulsion unit (12). The drive arrangement (5) further comprises a second gear box (21) and a second propulsion unit (22) operatively connected to the first drive axle (10) or to an optional second drive axle (20, 30). The drive arrangement (5) further comprises at least one electronic control unit (ECU) adapted to govern gear transmission of the first and the second gear boxes (11, 21). The electronic control unit (ECU) is configured to automatically select between shifting gear on the first and the second gear boxes (11, 21) simultaneously, or sequentially. The drive arrangement and the method provides for a very versatile drive arrangement and gear synchronization providing comfort for the driver and the passengers as well as improved vehicle dynamics.