Vehicle Diagnosis Bus Write Request Timing
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Solution Overview
Problem
The increasing load on vehicle diagnosis buses due to the use of diagnosis plug-in devices for data collection leads to significant collision rates and transmission delays, especially when using request/answer services, which can disrupt normal bus operations.
Innovation Solution
A method where the diagnosis plug-in device listens only after detecting a Bus Active condition, determines a write enable condition based on bus load and time, and carries out request/answer services during quiet instants on the bus, thereby minimizing disruption and collision rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diagnosis plug-in device continuously sends request/answer services on the diagnosis bus, then data collection productivity is improved, but collision rate and transmission delays increase significantly
Solution Approach 1:
The diagnosis plug-in device transitions from continuous operation to periodic action by sending requests only during quiet instants when bus load is below a threshold. The system monitors bus load levels and schedules requests accordingly, transforming continuous data collection into periodic, load-aware communication that avoids collisions while maintaining productivity.
Solution Approach 2:
The system dynamically adjusts its communication behavior based on real-time bus load conditions. The plug-in device monitors bus load levels and modifies its request transmission strategy accordingly - remaining silent during high-load periods and actively collecting data during low-load periods, making the system adaptive rather than static.
2Productivity
If the diagnosis plug-in device sends requests during high bus load periods, then data collection frequency is improved, but transmission delays and collisions increase
Solution Approach 1:
The system performs preliminary monitoring of bus load levels before transmitting requests. By detecting quiet instants in advance and preparing requests to be sent during these low-load periods, the system avoids transmission delays while maintaining adequate data collection frequency through proactive timing rather than reactive response.
3Stability of the object's composition
If the diagnosis plug-in device remains silent during initialization phase, then bus operation stability is improved, but data collection time is delayed
Solution Approach 1:
The system performs preliminary monitoring during the initialization phase to detect when the bus stabilizes and reaches a quiet instant. Rather than remaining silent indefinitely, the plug-in device proactively identifies suitable moments for request transmission after initialization, balancing stability with timely data collection.
Solution Approach 2:
The system dynamically transitions from a silent state during initialization to active request transmission once quiet instants are detected. This dynamic adaptation allows the plug-in device to respect the stability needs of the initialization phase while minimizing overall data collection time through timely engagement when conditions permit.
Data Source
AI summary
A method carried out in a system, the system comprising at least a diagnosis plug-in device (1) connected to the diagnosis plug (8) of a vehicle, a host server (2), one or more on-board ECUs (3), the method comprising the following steps: /a/ detect a Bus Active condition, either via an electrical pin on the diagnosis plug or via an analysis of activity level on at least one Diagnosis bus accessible at the diagnosis plug, /b/ cause the diagnosis plug-in device to listen only on the at least one Diagnosis bus after the Bus Active condition is detected, /c/ determine a write enable condition, according to evolution of bus load level on the at least one diagnosis bus and/or after a certain time elapsed since Bus Active condition was true, /e/ whenever the write enable condition becomes true, carry out the request/answer services to write requests on the diagnosis bus and retrieve, in the corresponding answers, various data from the board ECUs (3), to be decoded and forwarded to a client fleet management system, /e1/ determining, a cyclic pattern of messages circulating on the bus, with at least busy instants (IB) and quiet instants (IQ), /e2/ place write requests on the diagnosis bus at quiet instants (IQ).