Hybrid Vehicle Torque Synchronization via Preliminary Engine Action
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Solution Overview
Problem
In hybrid vehicles, the delay in communication between the engine and electric machine controllers via a CAN link causes engine torque to be reduced for an extended period, leading to driveline torque disturbances and inefficiencies, as the engine torque response precedes the electric machine torque response.
Innovation Solution
Adjusting the requested engine torque to align with or lead the electric machine torque response by modifying the arbitrated engine torque, ensuring the electric machine torque is commanded sooner to match the engine torque changes, thereby reducing driveline disturbances and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If torque commands are broadcast to the electric machine controller via CAN communications link, then the electric machine torque response is delayed, but the engine torque response begins sooner
Solution Approach 1:
The system performs preliminary actions by having the engine controller receive and process the torque request before the electric machine controller. The engine controller begins preparing the engine torque response in advance, while the torque command is simultaneously being transmitted to the electric machine controller via CAN bus. This preliminary action allows the engine torque to start changing before the electric machine torque, compensating for the communication delay and achieving synchronized torque delivery at the driveline.
2Stability of the object's composition
If engine torque is reduced for an extended period to wait for electric machine torque response, then torque synchronization is improved, but driveline efficiency decreases
Solution Approach 1:
The engine controller performs preliminary action by receiving and processing the torque request in advance, allowing it to begin adjusting engine torque before the electric machine controller responds. This eliminates the need for extended engine torque reduction waiting for electric machine response, as the engine torque naturally leads the electric machine torque to achieve synchronization, thereby maintaining driveline efficiency.
Solution Approach 2:
The system uses feedback from the torque request signal to coordinate the timing of engine and electric machine torque responses. The engine controller receives feedback about the torque request and adjusts engine torque accordingly, while the electric machine controller receives the same torque request via CAN bus and adjusts electric machine torque. This feedback mechanism ensures both controllers respond to the same command, achieving torque synchronization without energy loss.
3Device complexity
If engine and electric machine torques are delivered at different times, then communication architecture is maintained, but driveline torque disturbances occur
Solution Approach 1:
The engine controller performs preliminary action by receiving and processing the torque request before the electric machine controller. This timing arrangement causes the engine torque to lead the electric machine torque, which compensates for the CAN bus communication delay. The result is that both torques arrive at the driveline simultaneously, eliminating torque disturbances while preserving the distributed controller architecture with separate engine and electric machine controllers.
Data Source
AI summary
Systems and methods for operating a vehicle that includes an engine and an electric machine are described. In one example, torque requests are aligned in time to compensate for a delay that may be caused by broadcasting one or more torque commands over a controller area network or another type of communication link. The torque requests may be aligned via delaying an engine torque request and predicting an electric machine torque.