Vehicle OBD Bitrate Detection for Remote Diagnostics
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Solution Overview
Problem
Existing vehicle diagnostic systems face challenges in determining the communication protocol and bitrate for interfacing with a vehicle's On-Board Diagnostics (OBD) system, which can vary significantly across different vehicles and are not readily ascertainable from documentation.
Innovation Solution
A communication system comprising a vehicle-side device and a tool-side device, where the vehicle-side device is configured to connect to the OBD system and determine the bitrate by monitoring communication outputs and using an onboard computer clock to track elapsed time, allowing bi-directional communication between the OBD system and remote network devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If remote networking systems are used to access OBD systems, then diagnostic and programming functions can be performed remotely, but determining the communication protocol and bitrate becomes difficult because these parameters vary significantly across vehicles and are not readily ascertainable from documentation
Solution Approach 1:
The system performs preliminary bitrate detection and protocol identification automatically before establishing remote diagnostic or programming sessions. The vehicle-side device monitors communication outputs and measures pulse widths to determine the OBD system's bitrate in advance, eliminating the need for technicians to manually research or guess communication parameters before remote access
Solution Approach 2:
The system enables self-service by allowing the OBD system to automatically provide its own communication parameters through active monitoring. The vehicle-side device listens to communication outputs from the OBD system and extracts bitrate information directly from the system itself, rather than requiring external documentation or manual configuration
2Reliability
If standardized OBD protocols are used, then basic diagnostic functions are reliable, but advanced computerized systems require non-standardized protocols and bitrates that are not published or documented
Solution Approach 1:
The system transitions from static, pre-configured protocol settings to dynamic, adaptive bitrate detection. The vehicle-side device actively monitors communication outputs and adjusts its understanding of the OBD system's bitrate in real-time, allowing reliable communication with both standardized and non-standardized advanced systems without requiring separate configuration for each
Solution Approach 2:
The system changes its approach from using fixed, documented protocol parameters to dynamically determining parameters through measurement. By monitoring communication outputs and analyzing pulse widths, the system adapts to different bitrate parameters used by various vehicle systems, including advanced computerized systems with non-standardized protocols
Data Source
AI summary
A method of remote communications with an on-board diagnostics (OBD) system of a vehicle includes connecting a vehicle communications device to a connector of a vehicle's OBD system, connecting a remote communications device to a connector of a vehicle tool device, and establishing a network communications link between the vehicle communications device and a remote communications device. The vehicle communications device receives communications at the ve-hicle-communications device from the vehicle's OBD system through the connector. A bit stream of the received communications is analyzed over an interval of time.