Vehicle ECU Activation Sequencing for Reliable Timer Operations
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Solution Overview
Problem
In vehicle control systems with multiple ECUs, activation timing deviations lead to communication abnormalities and erroneous failure detection when ECUs are activated at different times, particularly in hierarchical configurations with timer-based functions like timer charging or air conditioner operations.
Innovation Solution
A vehicle control apparatus with a host unit and lower units, where the host unit specifies and coordinates the activation of lower units by outputting an activation request command followed by an operation start command after a predetermined time, ensuring all units are activated before starting operations to prevent communication abnormalities and erroneous failure detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each ECU is activated independently without coordination, then the system can start operations quickly, but communication abnormalities and erroneous failure detection occur due to activation timing deviations
Solution Approach 1:
The host unit sends activation request commands to all lower units before the operation start command. This preliminary activation ensures all ECUs are ready and can communicate properly before the actual operation begins, preventing communication abnormalities and erroneous failure detection.
Solution Approach 2:
The host unit acts as an intermediary that coordinates the activation timing of all lower units. By controlling the sequence of activation requests and the operation start command, the host unit ensures synchronized activation across all ECUs, eliminating timing deviations that cause communication issues.
2Reliability
If failure detection is always performed as in conventional systems, then system reliability can be monitored continuously, but communication abnormalities occur with ECUs that are not yet activated
Solution Approach 1:
The system performs failure detection after all lower units have been activated by activation request commands but before the operation start command is sent. This timing ensures all ECUs are active and can communicate properly, allowing accurate failure detection without communication abnormalities.
Solution Approach 2:
The failure detection timing is made dynamic rather than fixed. The system adapts the failure detection moment to occur after activation requests are sent but before operation starts, adjusting the detection timing based on the activation sequence to avoid communication issues with inactive ECUs.
Data Source
AI summary
A vehicle control apparatus includes a plurality of control units communicable with each other. The plurality of control unit includes a host unit and a plurality of lower units managed by the host unit. The vehicle control apparatus configured to perform: specifying a lower unit used for executing a predetermined operation among the plurality of lower units when received a signal for instructing any one of the plurality of lower units to start the predetermined operation of the vehicle control apparatus; outputting an activation request command to the lower unit used for executing the predetermined operation; and outputting, after a predetermined time elapsed since the activation request command is output, an operation start command of the predetermined operation to the lower unit used for executing the predetermined operation.