Sensorless Driveline Disconnect State Detection for Safe Clutch Engagement
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Solution Overview
Problem
Existing disconnect technologies in vehicle drivelines lack effective sensors for clutch state feedback, leading to potential damage from partial engagement and asymmetrical torque delivery, especially under high torque conditions, which can result in reduced efficiency and increased energy loss.
Innovation Solution
Implementing control logic and a closed-loop speed controller to synchronize motor and wheel speeds before disconnect engagement, and using a vehicle dynamics module to determine the disconnect state through motor and wheel speed correlation and torque response analysis, without the need for direct sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If disconnects are actuated quickly at any vehicle speed, then productivity is improved, but reliability deteriorates due to potential damage from partial engagement
Solution Approach 1:
The control logic synchronizes motor and wheel speeds before actuating the disconnect, ensuring speed delta is within threshold. This preliminary speed matching prevents partial engagement damage while enabling quick actuation at any vehicle speed.
Solution Approach 2:
The intrusive state-detection diagnostic continuously monitors disconnect engagement state by analyzing motor and wheel speed correlation. This feedback mechanism detects partial engagement conditions and prevents torque application that could damage the disconnect components.
2Reliability
If sensors are added to detect clutch state, then reliability is improved, but device complexity increases
Solution Approach 1:
The system uses existing motor and wheel speed sensors to self-determine disconnect engagement state through speed correlation analysis. No additional clutch position sensors are required, as the system leverages available data to perform state detection.
Solution Approach 2:
The control logic acts as an intermediary that infers disconnect state from the relationship between motor speed and wheel speed. Instead of directly sensing clutch position, the system uses speed differential as a mediator to determine engagement state.
3Power
If torque is applied during partial engagement, then power transmission is improved, but object-generated harmful factors worsen due to mechanical deformation
Solution Approach 1:
The control logic ensures complete disconnect engagement before applying torque by verifying speed synchronization. This preliminary engagement confirmation prevents torque application during partial engagement, avoiding mechanical deformation of clutch components.
Solution Approach 2:
The state-detection diagnostic provides feedback on disconnect engagement status by monitoring speed correlation. Torque application is enabled only when the diagnostic confirms full engagement, preventing mechanical damage while ensuring efficient power transmission.
Data Source
AI summary
A sensorless clutch state feedback method is provided including a driveline disconnect. To engage the sensorless disconnect, respective speeds of a motor assembly and the sensorless disconnect are synchronized to within a speed delta threshold of each other, a control system facilitates the engagement of the motor assembly and the sensorless disconnect, and the control system determines the success of the engagement by the motor speed response of the motor assembly (e.g., whether the presence of a load is detected).