MHSG Torque Deviation Diagnosis During Catalyst Heating
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Solution Overview
Problem
Current systems for mild hybrid starter and generator (MHSG) failure diagnosis in mild hybrid vehicles require additional sensors and are inefficient in diagnosing failures when assisting engine torque for catalyst heating after engine start, particularly in adhering to North-America On Board Diagnosis (OBD) regulations.
Innovation Solution
A system and method that utilize existing sensors like crank position and water temperature sensors to detect deviations in required and actual torque of the MHSG, determining catalyst activation needs and initiating failure diagnosis without additional sensors, using a controller with catalyst activation, failure diagnosis start, and judgment parts to assess torque deviations and communicate through CAN network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors are added to diagnose MHSG failure during catalyst heating operation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses existing sensors (crank position sensor, water temperature sensor) that already serve other functions to also provide data for MHSG failure diagnosis during catalyst heating. The controller self-services by processing torque deviation calculations using data from these multi-purpose sensors, eliminating the need for dedicated diagnosis sensors.
Solution Approach 2:
Existing sensors in the system are made multi-functional: the crank position sensor provides both engine speed control data and torque calculation data for failure diagnosis; the water temperature sensor provides both cooling control data and catalyst activation status data. This universal usage resolves the contradiction by improving diagnosis capability without adding sensors.
2Reliability
If MHSG failure diagnosis is performed during catalyst heating operation, then reliability is improved, but ease of operation deteriorates due to complex control requirements
Solution Approach 1:
The failure diagnosis function is merged with the existing catalyst heating control operation. The controller simultaneously performs catalyst activation control and MHSG failure diagnosis using the same sensor data and control loops. This integration improves reliability by covering more operating conditions while maintaining ease of operation through unified control logic.
Solution Approach 2:
The system implements feedback by continuously monitoring torque deviation between required and actual MHSG torque during catalyst heating operation. When deviation exceeds thresholds, the controller provides feedback diagnostic information. This automated feedback mechanism improves reliability without requiring complex manual operation.
3Measurement precision
If torque deviation method is used for MHSG failure diagnosis, then measurement precision is improved, but device complexity increases due to additional control logic
Solution Approach 1:
The controller acts as an intermediary that calculates torque deviation using existing sensor data (crank position, water temperature) and MHSG operating parameters. Rather than adding complex measurement hardware, the controller mediates between available data sources and failure diagnosis requirements through software-based torque deviation calculation, improving precision without proportionally increasing hardware complexity.
Data Source
AI summary
An embodiment system for mild hybrid starter and generator (MHSG) failure diagnosis of a mild hybrid vehicle includes a data detection part configured to detect data for determining whether to activate a catalyst, and a controller configured to determine whether there is an MHSG failure using a deviation between a required torque and an actual operating torque of an MHSG after determining whether catalyst activation is needed and whether to start a stage of the MHSG failure diagnosis based on the data detected by the data detection part.