Hybrid Vehicle Torque Monitoring via Electrical Calculation
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Solution Overview
Problem
Hybrid electric vehicles lack reliable torque monitoring without additional torque sensors, leading to reduced reliability in controlling engine and motor torque, which affects drivability and fuel efficiency.
Innovation Solution
A method to monitor engine and motor torque by calculating output torque based on high voltage battery discharging power, electric load consumption, and motor speed, comparing difference values with reference values to enter fail-safe mode or correct torque maps, eliminating the need for additional torque sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque sensors are installed to measure engine torque and motor torque, then measurement precision and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical torque sensors with an electrical calculation-based system. The control unit calculates actual torque values by processing electrical signals from existing sensors (accelerator pedal position sensor, brake pedal position sensor, motor current sensor) and pre-stored torque maps, substituting mechanical measurement with electrical computation to avoid additional mechanical components
Solution Approach 2:
The patent creates a virtual copy of torque measurement functionality through software calculation. Instead of physically measuring torque with sensors, the system computes equivalent torque values by copying and processing data from existing sensors and combining them with lookup tables, achieving the same functional goal without physical duplication of measurement hardware
2Reliability
If torque sensors are installed to measure engine torque and motor torque, then reliability is improved, but cost increases
Solution Approach 1:
The patent replaces mechanical torque sensors with an electrical calculation-based system. The control unit calculates actual torque values by processing electrical signals from existing sensors (accelerator pedal position sensor, brake pedal position sensor, motor current sensor) and pre-stored torque maps, substituting mechanical measurement with electrical computation to avoid additional mechanical components
Solution Approach 2:
The system uses its own existing sensors and control unit to perform torque measurement functions that would otherwise require separate dedicated torque sensors. The control unit serves multiple functions including both control decisions and torque measurement, making the system self-sufficient and eliminating the need for additional specialized components
3Device complexity
If prediction-based torque control is used without torque sensors, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously compares accelerator pedal position, brake pedal position, and motor current data against pre-stored torque maps to calculate actual torque values. This closed-loop feedback approach using multiple sensor inputs significantly improves measurement precision compared to simple open-loop prediction methods
Solution Approach 2:
The control unit performs multiple functions simultaneously: it controls motor operation, monitors driver intent through pedal sensors, and calculates torque values by integrating data from all these sources with lookup tables. This multi-functional approach allows the system to achieve precise torque measurement without dedicated torque sensors, as the control unit universally processes all necessary information
Data Source
AI summary
A method for monitoring a torque in a hybrid electric vehicle includes calculating an output torque of a motor based on a discharging power of a high voltage battery, a consumption power of a plurality of electric loads, and a motor speed. A first difference value between a motor torque command and the calculated output torque of the motor is calculated. The first difference value is compared with a first reference value. When the first difference value is larger than the first reference value, the hybrid electric vehicle is entered in a fail safe mode.