Dynamic Torque Limiting via Steering Angle for Driveline Protection
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Solution Overview
Problem
Existing engine control systems fail to effectively limit engine torque output during sharp turns to prevent damage to front half shafts in four-wheel drive or all-wheel drive vehicles, while maintaining driver control over torque output.
Innovation Solution
An engine control system comprising a limit determination module that varies torque limits based on steering angle, measured by a steering angle sensor, and a torque control module that limits engine torque output to protect front half shafts, with enabling/disabling functionality based on drive modes to adjust torque transfer to front wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined maximum torque limit is applied to protect front half shafts, then half shaft damage is prevented, but driver control over torque output is unnecessarily restricted
Solution Approach 1:
The torque limit is made dynamic by varying it based on steering angle. When the steering angle exceeds a threshold indicating a sharp turn, the torque limit is reduced to protect half shafts. When steering angle is within normal range, the torque limit returns to maximum, maintaining full driver control. This dynamic adjustment resolves the contradiction by adapting the protection level to actual driving conditions.
Solution Approach 2:
The system changes the torque limit parameter based on steering angle measurements. By monitoring steering angle as a control parameter and adjusting the torque limit accordingly, the system achieves conditional protection: maximum torque is allowed during normal driving, while reduced torque limits apply only during sharp turns that risk half shaft damage.
2Reliability
If torque output is limited during sharp turns, then front half shafts are protected from damage, but vehicle performance is reduced
Solution Approach 1:
The torque limit parameter is changed based on steering angle conditions. During sharp turns (high steering angle), the torque limit parameter is reduced to protect the drivetrain. During normal driving (low steering angle), the torque limit parameter returns to maximum, maintaining full power output and vehicle performance.
Solution Approach 2:
The torque limitation is made dynamic rather than static. The system continuously monitors steering angle and adjusts torque limits in real-time, applying power restrictions only when half shaft damage risk is detected, while maintaining full power availability during normal operating conditions.
3Measurement precision
If a steering angle sensor is added to dynamically adjust torque limits, then protection accuracy is improved, but device complexity increases
Solution Approach 1:
A steering angle sensor provides feedback to the ECM about the current steering angle. The ECM uses this feedback signal to determine whether to apply torque limiting. This feedback mechanism improves measurement precision for detecting sharp turns while using existing ECM processing capability to minimize additional system complexity.
Solution Approach 2:
The steering angle sensor acts as an intermediary that provides precise steering angle measurements to the control system. Rather than requiring complex direct monitoring of half shaft stress or other difficult-to-measure parameters, the sensor serves as a simple intermediary that enables accurate detection of sharp turn conditions through readily available steering angle data.
Data Source
AI summary
An engine control system comprises a limit determination module and a torque control module. The limit determination module selectively varies a torque limit based on a steering angle. The torque control module selectively limits torque output by an engine to the torque limit.