AMT Gear Control for Soft Surface Traction
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Solution Overview
Problem
Automatic Manual Transmissions (AMTs) face challenges in effectively managing gear selection across a wide variety of operating conditions, particularly in soft surface environments like sand, snow, or wet mud, where normal control modes fail to provide sufficient traction and driving force, leading to wheel slip and inability to climb hills.
Innovation Solution
A powertrain system with a control unit that employs two distinct gear selection control algorithms: a normal mode and a soft surface mode. The soft surface mode shifts gears at higher engine speeds, includes more gear shifts, and allows for quicker torque ramps, while considering steering angle and travel resistance to optimize gear changes for improved traction on loose surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If normal gear selection control algorithm is used, then vehicle operates efficiently on ordinary roads, but vehicle cannot provide sufficient driving force on soft surfaces leading to wheel slip and inability to climb hills
Solution Approach 1:
The control system dynamically switches between normal and soft surface gear selection control algorithms based on detected road conditions. The system adapts its gear selection strategy in real-time by selecting the appropriate algorithm when soft surface conditions are detected, enabling reliable operation across diverse road conditions.
Solution Approach 2:
The system changes control parameters by switching between different gear selection algorithms. The soft surface algorithm modifies gear selection behavior by delaying upshifts and maintaining lower gears longer, providing sustained high torque delivery appropriate for soft surface conditions while preserving efficient normal operation on ordinary roads.
2Force
If gear is shifted down to provide more torque on soft surfaces, then driving force increases, but wheels start to slip due to loose surface material
Solution Approach 1:
The soft surface control algorithm performs preliminary action by proactively delaying gear upshifts before wheel slip occurs. By maintaining lower gears and higher engine speeds preemptively, the system delivers continuous high torque without the need for reactive gear downshifts that would cause wheel spin on loose surfaces.
Solution Approach 2:
The system uses feedback from wheel slip detection and engine load sensors to maintain appropriate gear selection. When soft surface conditions are detected, the control algorithm continuously monitors operating parameters and maintains gear selections that provide sufficient torque while preventing the harmful feedback loop of slip-induced gear changes.
3Adaptability or versatility
If multiple gear shifts are performed to optimize traction, then vehicle can navigate soft surfaces better, but gear shift frequency increases causing more interruptions in power delivery
Solution Approach 1:
The soft surface control algorithm performs preliminary gear selections that anticipate upcoming traction needs. By pre-selecting appropriate gears before wheel slip or power interruption occurs, the system reduces the frequency of reactive gear shifts and minimizes interruptions in power delivery while maintaining optimal traction.
Data Source
AI summary
A method and system for controlling a powertrain in a vehicle includes steps including registering a road condition. If the registered road condition corresponds to normal road conditions then a first gear selection control algorithm is used intended for driving the vehicle in a normal mode corresponding to the conditions on an ordinary road. If the registered road condition corresponds to soft surface road conditions then a second gear selection control algorithm is used intended for driving the vehicle in a soft surface mode corresponding to the conditions on an soft surface road. In this way, a vehicle can be adapted to be provided with an AMT to work in a satisfactorily way under an increased diversity of conditions.