Powertrain Lash Management via Foot Motion and Traffic Sensors
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Solution Overview
Problem
Existing methods for managing lash in vehicle drivelines lack lead information on driver intent, leading to slow vehicle response and driver discomfort due to unnecessary lash adjustments during torque transitions.
Innovation Solution
A method that distinguishes between driver intent to brake or coast using foot motion and traffic patterns, adjusting lash adjustments accordingly to optimize torque transitions and reduce frequency through the lash region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driveline torque is adjusted during accelerator pedal tip-out assuming driver will brake, then lash adjustments are made to prepare for negative torque, but vehicle response slows and driver discomfort increases when driver coasts instead of braking
Solution Approach 1:
The system performs preliminary lash adjustments by detecting foot-off pedal events and predicting driver intent using foot motion sensors and traffic pattern analysis. When braking is predicted, the system pre-adjusts lash to negative torque conditions. When coasting is predicted, the system maintains current torque state, avoiding unnecessary adjustments and preserving fast vehicle response.
Solution Approach 2:
The system continuously monitors foot motion sensors, traffic sensors, and accelerator/brake pedal positions to provide real-time feedback on driver intent. This feedback loop allows the control system to distinguish between braking intent (foot moving toward brake pedal) and coasting intent (foot remaining near accelerator), enabling accurate prediction and appropriate lash management decisions.
2Reliability
If driveline torque transitions through lash zone multiple times during coasting, then torque adjustments are made assuming braking intent, but driver discomfort increases due to repeated lash adjustments
Solution Approach 1:
The system performs preliminary assessment of driver intent using foot motion sensors and traffic pattern analysis before initiating torque transitions. When coasting is predicted (foot remains near accelerator, traffic clearing), the system maintains current positive torque state and avoids unnecessary transitions through the lash zone, thereby eliminating repeated clunk events and driver discomfort.
Solution Approach 2:
The system changes the torque parameter based on predicted driver intent. When braking is predicted, torque transitions to negative values with appropriate lash adjustments. When coasting is predicted, torque remains positive without unnecessary transitions, changing the operational parameter to match actual driver behavior and reduce harmful lash zone crossings.
Data Source
AI summary
Methods and systems are provided for adjusting powertrain torque in a vehicle based on driver intent. Driver intent is inferred based on foot motion inside a foot well monitored via a foot well region sensor and changes in clearance outside the vehicle monitored via a range sensor. By adjusting powertrain torque based on operator foot motion and traffic movements outside the vehicle, frequency of lash transitions can be reduced and lash transition initiation can be adjusted based on expected changes in torque demand.