Active Driveline Control for NVH Reduction in Mode Transitions
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Solution Overview
Problem
Existing dynamic driveline systems in motor vehicles often require user intervention or are inefficient in transitioning between two-wheel and four-wheel drive modes, leading to suboptimal performance and increased noise, vibration, and harshness (NVH) during mode changes.
Innovation Solution
An active driveline system that automatically transitions between two-wheel and four-wheel drive modes based on vehicle speed, torque, steering angle, and slip conditions, using releasable torque transmitting means such as clutches, which can connect or disconnect wheels quickly and efficiently without the need for user input, optimizing performance and reducing NVH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic driveline reconnect systems are used to enable four-wheel drive operation while moving, then the vehicle can adapt to changing driving conditions, but noise, vibration, and harshness (NVH) increase during mode transitions
Solution Approach 1:
The control system predicts wheel slip conditions using a predictive evaluator that monitors operating parameters before actual slip occurs. This allows the driveline to transition to four-wheel drive mode proactively, avoiding the harshness and vibration associated with reactive transitions during active wheel slip. The system performs the mode change in advance, before the harmful dynamic conditions develop.
Solution Approach 2:
The system employs both reactive and predictive evaluators that continuously monitor wheel slip and operating parameters. This feedback mechanism allows the control system to make informed decisions about when to transition between drive modes, optimizing the timing to minimize NVH while maintaining adaptability to changing driving conditions.
2Reliability
If reactive evaluator systems are used to determine driveline mode transitions, then the system responds to actual wheel slip conditions, but the transition occurs after performance degradation has already happened
Solution Approach 1:
The predictive evaluator analyzes operating parameters to forecast wheel slip conditions before they occur. This allows the system to transition to four-wheel drive mode in advance, eliminating the time delay inherent in reactive systems. The mode change happens proactively, maintaining optimal traction without waiting for performance degradation to occur.
Solution Approach 2:
The dual-evaluator system combines reactive monitoring of actual wheel slip with predictive analysis of operating parameters. This feedback loop enables the system to balance reliability in detecting actual conditions with timely response, transitioning modes based on predicted needs rather than waiting for degradation to occur.
3Ease of operation
If user-operable selectors are provided for two-wheel or four-wheel operation, then the driver has control over driveline mode, but the system requires user intervention and cannot automatically adapt to changing conditions
Solution Approach 1:
The driveline control system automatically monitors wheel slip and operating parameters, then autonomously transitions between two-wheel and four-wheel drive modes without requiring driver input. The system serves itself by making intelligent decisions based on real-time feedback from sensors and evaluators, eliminating the need for manual selector intervention while maintaining full driver control capability if needed.
Data Source
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AI summary
The invention relates to a motor vehicle driveline and a method of controlling same. The driveline includes front wheels (11, 12) and rear wheels (14, 15), a controller (40) and a prime mover (11). Either the front wheels (11, 12) or all wheels are connected to the prime mover (11). The rear wheels (14, 15) may be connected via a prop shaft (23) with clutches (22; 27) at both ends. The decision to switch between 2WD and 4WD is taken on basis of speed-dependent trigger conditions.