Dual-Clutch Transmission Shift Reversal for Off-Road Packaging Limits
Solution Overview
Problem
Dual-clutch transmissions have not been widely adopted in off-road vehicles due to high manufacturing costs and packaging issues, particularly in the limited engine compartment space, which hinders efficient packaging and deployment.
Innovation Solution
A method for controlling a powertrain with a dual-clutch transmission that includes a first and second clutch, a subtransmission with high and low gear settings, and a controller to manage gear shifts without interrupting torque distribution, allowing for efficient shifting and torque control during gear changes, enabling the use of dual-clutch transmissions in off-road vehicles by optimizing packaging and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dual-clutch transmission is used in off-road vehicles, then shifting performance and efficiency are improved, but manufacturing costs and packaging complexity increase
Solution Approach 1:
The transmission system is divided into a main transmission with odd gears on a first shaft and even gears on a second shaft, with a separate subtransmission handling high/low range selection. This segmentation allows independent optimization of each subsystem and simplifies the overall packaging by distributing components across different functional modules.
Solution Approach 2:
The subtransmission is integrated within the dual-clutch transmission assembly, with the high/low range gears nested within the existing main transmission structure. This nesting approach reduces the overall packaging volume by utilizing existing spaces and structural elements rather than adding separate external components.
2Productivity
If a dual-clutch transmission is used in off-road vehicles, then shifting performance is improved, but manufacturing costs increase
Solution Approach 1:
The subtransmission high/low range mechanism is designed to be compatible with standard dual-clutch transmission components and manufacturing processes. By using universal design principles and standardizing interfaces, the system can leverage existing supply chains and manufacturing capabilities, thereby reducing overall manufacturing costs despite the enhanced functionality.
3Productivity
If space in the engine compartment is limited, then packaging of the dual-clutch transmission is difficult, but efficient packaging is needed for off-road vehicle deployment
Solution Approach 1:
The transmission system utilizes vertical stacking of shafts and gears to accommodate multiple gear sets within a compact footprint. By arranging the first shaft for odd gears and the second shaft for even gears in different vertical planes, the design maximizes space utilization in the limited engine compartment volume without compromising shifting performance.
Data Source
AI summary
A method for controlling a powertrain of a vehicle, the powertrain a dual-clutch transmission including a first clutch and a second clutch selectively actuated to transmit motion from the engine to a first shaft and a second shaft respectively. The method includes producing a first shift request for shifting from an initial gear to a different gear; in response to the first shift request, executing a first shift sequence to shift from the initial gear to the different gear; during execution of the first shift sequence, producing a second shift request for shifting from the different gear to the initial gear; in response to the second shift request: interrupting the first shift sequence prior to the first shift sequence having finished; and executing a second shift sequence to reverse the first shift sequence such that the transmission engages the initial gear for driving on the first shaft.