Hybrid AWD Axle Torque Split Control With Real-Time Optimization
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Solution Overview
Problem
Determining an optimal torque split between the primary and secondary axles of a hybrid vehicle in real-time is challenging due to its inherent multi-variable optimization nature, leading to sub-optimal vehicle operation.
Innovation Solution
A method and system that utilize a processor to perform real-time optimization, determining primary and secondary axle torque targets that minimize an objective cost function, adjusting torque splits, and controlling electric motors and engines to meet torque requests while maintaining a charge-neutral current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If real-time optimization is performed to determine optimal torque split between primary and secondary axles, then vehicle performance and efficiency are improved, but computational complexity and processing requirements increase
Solution Approach 1:
The system performs preliminary calculations of torque targets for both primary and secondary axles before final torque distribution. The processor pre-calculates optimal torque split based on current vehicle conditions, then applies these pre-computed targets to control the electric motors and engine, reducing real-time computational burden while maintaining optimization benefits
Solution Approach 2:
The torque control problem is segmented into separate optimization for primary axle torque target and secondary axle torque target. The processor independently determines each axle's torque contribution based on vehicle conditions, then combines them to meet total torque request. This segmentation simplifies the multi-variable optimization into more manageable sub-problems that can be solved in real-time
2Loss of energy
If torque requirements are precisely determined for optimal operation, then vehicle efficiency improves, but measurement and control difficulty increases
Solution Approach 1:
The system continuously monitors actual vehicle conditions including torque requests, electric motor outputs, and engine performance. The processor compares actual torque delivery against target values and adjusts torque distribution in real-time based on feedback from vehicle sensors and operating conditions, ensuring optimal efficiency while simplifying control through closed-loop regulation
Solution Approach 2:
The processor acts as an intermediary that translates complex multi-variable optimization requirements into simple torque target commands for the primary and secondary axles. It mediates between the total torque request and the individual axle contributions, converting difficult-to-measure optimal torque requirements into straightforward control signals that can be easily implemented by the motor controllers
Data Source
AI summary
A system performs a method for operating a vehicle. A raw total axle torque request for the vehicle is received at a processor of the vehicle. The vehicle includes a primary axle, one or more electric motors on the primary axle, an engine coupled to the primary axle, a secondary axle, and an additional electric motor on the secondary axle. The processor performs an optimization to determine a primary axle torque target and a secondary axle torque target that meets the raw total axle torque request while locating a value representative of a minimum of an objective cost function for the vehicle, controls the one or more electric motors and the engine at the primary axle using the primary axle torque target; and controls the additional electric motor at the secondary axle using the secondary axle torque target.