Hybrid Transmission Kinematic Mode Detection via Software Sensor
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Solution Overview
Problem
In hybrid vehicle transmissions, the reliability of determining the current kinematic mode is compromised by sensor failures or mechanical issues, as existing methods heavily rely on sensor data for gearbox control, which can be unreliable.
Innovation Solution
A method using a vector with at least two components representing the reduction ratios of each traction chain to identify the kinematic mode, allowing for the creation of a software sensor that detects anomalies without duplicating physical sensors, by observing the rotation speeds of the thermal engine, electric machine, and vehicle wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical sensors are used to detect the state of traction chains and determine kinematic mode, then measurement information is obtained, but reliability is compromised by sensor failures or measurement drift
Solution Approach 1:
The patent creates a software sensor that copies the function of physical sensors by calculating reduction ratios from observed rotation speeds. Instead of relying on physical sensors to directly detect kinematic mode, the system computes a virtual sensor output based on the relationship between engine speed, electric machine speed, and wheel speed, thereby eliminating sensor failure risks while maintaining detection accuracy
Solution Approach 2:
The patent replaces the mechanical sensor-based detection system with a computational method that uses the fundamental kinematic relationships in the hybrid transmission. By substituting physical sensing with mathematical calculation based on observable speeds, the system eliminates the reliability issues inherent in mechanical sensors while preserving the ability to accurately determine kinematic mode
2Reliability
If additional physical sensors are installed to verify sensor reliability and detect anomalies, then measurement reliability is improved, but device complexity and cost increase
Solution Approach 1:
The system performs self-verification by using the inherent kinematic relationships in the hybrid transmission to validate sensor readings. The software sensor calculates expected reduction ratios from independently measurable speeds (engine, electric machine, wheels) and compares these with sensor-reported values, enabling the system to detect sensor failures without requiring additional verification sensors
Solution Approach 2:
The control unit performs multiple functions: it controls the hybrid transmission operation and simultaneously verifies sensor reliability through software sensor calculations. This multi-functionality eliminates the need for dedicated verification sensors, reducing system complexity while maintaining the ability to detect sensor anomalies and ensure reliable operation
Data Source
Figure 1
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AI summary
Method for determining the current kinematic mode of a hybrid transmission which combines on an output differential to the wheels of the vehicle a traction chain transmitting the torque of a thermal engine on discrete reduction ratios established by a first reducer and an electric traction chain transmitting the torque of an electric machine on several discrete reduction ratios established by a second reducer, characterized in that the kinematic mode is identified by the state of a vector with at least two components [Ratio_Mth ; Ratio_ME], representing the reduction ratio on each of the two traction chains.