Hybrid Controller Mediator for CAN Bus Conflict Resolution
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Solution Overview
Problem
The increased complexity of hybrid electric drive systems in vehicles leads to conflicts in controller area network (CAN) messages, particularly in parallel hybrid vehicles with PTO capability, resulting in potential conflicts and increased data traffic, which complicates the management of thermal engine angular velocity and torque changes.
Innovation Solution
Modifying the CAN messaging strategy to route thermal engine torque and angular velocity change requests from low-priority nodes through an intermediary hybrid controller, creating a logical series relationship among controllers, and using auxiliary datalink messages to conflate requests, thereby reducing conflicts and optimizing data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple controllers broadcast torque and speed requests directly to the engine controller on the CAN bus, then the system maintains high responsiveness and direct control, but conflicting messages increase data traffic and create control conflicts
Solution Approach 1:
The patent introduces a hybrid controller as an intermediary node between body controllers and the engine controller. Body controllers broadcast torque and speed requests to the hybrid controller, which then consolidates these requests with its own control objectives and broadcasts a single unified message to the engine controller. This intermediary structure eliminates message conflicts while maintaining control responsiveness.
2Adaptability or versatility
If the system uses conventional CAN messaging with multiple independent controllers, then each controller can independently manage its functions, but the thermal engine receives conflicting requests leading to increased data traffic
Solution Approach 1:
The patent merges multiple independent control requests into a single unified message. The hybrid controller receives torque and speed requests from various body controllers, combines these with its own hybrid control objectives, and transmits a consolidated single message to the engine controller. This merging reduces data traffic volume while preserving the adaptability of individual controllers through the hybrid controller's coordination.
3Ease of operation
If body controllers with low arbitration priority broadcast engine control requests, then they can access the CAN bus for PTO operations, but their messages may be overridden by higher priority controllers
Solution Approach 1:
The hybrid controller serves as a mediator that receives control requests from low-priority body controllers and ensures their reliable execution. By consolidating these requests and broadcasting them through the hybrid controller's higher priority channel, the system ensures that PTO operation requests are reliably executed without being overridden by arbitration conflicts.
Data Source
AI summary
Messaging in a controller area network is modified to hide thermal engine torque and angular velocity change requests originating with selected nodes with relatively low contention access priority from an engine controller and to route the messages instead through an intermediary controller which is an independent source of thermal engine torque and angular velocity change requests. More specifically, in a hybrid vehicle having a body controller with operational control over power take off equipment, a hybrid controller and a thermal engine controller, angular velocity and torque change requests to support power take off operation are embedded in auxiliary input/output messages. The hybrid controller operates on these auxiliary messages, conflating the embedded angular velocity and torque change requests with its own and rebroadcast in conventional form.