Powertrain Torque Estimation via Rotational Angle Discrepancy
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Solution Overview
Problem
Existing vehicle transmission systems lack efficient methods to estimate torque levels and detect clutch fill status, which are crucial for smooth power flow and control, as this information is not readily available.
Innovation Solution
A system utilizing a pair of speed sensors positioned with respect to rotatable members in the powertrain, communicating with a controller to estimate torque by calculating the discrepancy in rotational angles and detect clutch fill through monitoring input, output, and intermediate speed signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If speed sensors are used to estimate torque through rotational angle discrepancy, then torque estimation capability is improved, but device complexity increases due to additional sensors and control calculations
Solution Approach 1:
The system uses existing speed sensors (TISS, TOSS, TMSS) that are already installed for other transmission control functions to simultaneously estimate torque. No additional dedicated torque sensors are required, as the system makes the existing sensors serve dual purposes: speed monitoring and torque estimation through angle discrepancy calculation.
Solution Approach 2:
The controller acts as an intermediary that processes signals from existing speed sensors and calculates torque estimation through rotational angle discrepancy. Instead of directly measuring torque, the system uses the controller to interpret the angular difference between input and output members as a proxy for torque levels.
2Ease of manufacture
If existing speed sensors are utilized for torque estimation, then additional sensor installation cost is reduced, but measurement precision may be insufficient for accurate torque determination
Solution Approach 1:
The system changes the parameter being measured from direct torque to rotational angle discrepancy. By integrating speed sensor signals over time to obtain angular positions and calculating the difference between input and output member angles, the system transforms existing speed measurements into torque estimation data without requiring direct torque sensing.
Solution Approach 2:
The patent replaces mechanical torque sensing with an electrical/electronic measurement approach. Instead of using mechanical strain gauges or torque sensors on shafts, the system uses electrical speed sensors and computational algorithms to estimate torque based on rotational kinematics and the known mechanical properties of the transmission.
3Reliability
If torque estimation is implemented using rotational angle discrepancy, then clutch fill detection capability is improved, but control complexity increases
Solution Approach 1:
The controller continuously monitors rotational angle discrepancy in real-time and uses this feedback to detect clutch fill events. When the angle discrepancy reaches a threshold indicating that the oncoming clutch has been filled with hydraulic fluid, the controller adjusts control signals accordingly, creating a closed-loop feedback system for clutch management.
Solution Approach 2:
The system performs preliminary detection of clutch fill status by monitoring angle discrepancy before actual torque transfer begins. This allows the controller to prepare for the upcoming torque phase by pre-positioning control parameters, ensuring smooth transition and avoiding power flow interruptions.
Data Source
AI summary
A vehicle includes a powertrain having first and second rotatable members, speed sensors, and a controller. The speed sensors generate output signals encoding the speeds of the respective first and second rotatable members. The controller calculates a rotation angle of the members using the output signals and estimates a torque value in the powertrain as a function of the rotation angles. The sensors may count the teeth of respective first and second toothed gear elements and encode the count as the output signals. The controller may estimate the torque value as a function of a linear coefficient and the present gear ratio of the sensors. The controller may also detect a commanded upshift of the transmission and detect a fill event of an oncoming clutch of the transmission as a function of the corresponding rotation angles for the rotatable members. The members may be input, output, or intermediate members.