Driveline Torque Control Without Ground Speed Sensing
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Solution Overview
Problem
Vehicles without ground speed information cannot directly calculate wheel slip, leading to challenges in reducing wheel slip while maintaining high driveline output torque during demanding conditions.
Innovation Solution
A method for selecting and adjusting a vehicle standstill driveline output torque set point based on vehicle speed and accelerator pedal position, without direct ground speed data, using torque maps to control wheel slip and enhance tractive performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ground speed sensor data is used to directly calculate wheel slip, then wheel slip detection precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the ground speed sensor from the system and replaces it with an alternative approach using only wheel speed sensor data. The wheel slip calculation is reformed to use the difference between driven wheel speed and non-driven wheel speed, eliminating the need for ground speed sensors while maintaining wheel slip detection capability
Solution Approach 2:
The patent uses non-driven wheel speed as a reference copy to represent ground speed conditions. By comparing driven wheel speed against non-driven wheel speed, the system indirectly infers wheel slip without directly measuring ground speed, creating a functional substitute that achieves the same control objective
2Power
If driveline output torque is increased during standstill, then tractive performance is improved, but wheel slip increases
Solution Approach 1:
The patent implements dynamic adjustment of driveline output torque based on real-time wheel slip conditions. The torque is not fixed but continuously modulated according to the calculated wheel slip and vehicle speed, allowing the system to optimize the balance between tractive performance and slip prevention
Solution Approach 2:
The patent establishes a feedback control loop where wheel slip calculation results are fed back to adjust driveline output torque. The controller continuously monitors wheel slip conditions and modifies torque delivery accordingly, creating a closed-loop system that adapts to changing traction conditions
3Object-affected harmful factors
If driveline output torque is reduced to prevent wheel slip, then wheel slip is reduced, but tractive performance deteriorates
Solution Approach 1:
The patent applies partial torque reduction only when and where wheel slip is detected, rather than uniformly reducing torque across all conditions. The control strategy selectively modulates torque to the extent necessary to prevent slip while maintaining maximum possible tractive performance in other aspects
Data Source
AI summary
Traction control systems and methods are provided. In one example, a method for operating a driveline system includes selecting a vehicle standstill driveline output torque set point that maps to a pedal position and adjusting the vehicle standstill driveline output torque set point based on vehicle speed and accelerator pedal position. Adjusting the output torque includes ramping up the output torque set point when vehicle acceleration is less than a threshold value.