OBD to DMI Interface Pulse Conversion for Vehicle Compatibility
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Solution Overview
Problem
Existing distance measuring instruments (DMI) face challenges in compatibility with modern vehicles due to varying cable locations and complexities in accessing the vehicle speed sensor (VSS) signal, leading to difficult installations, susceptibility to electromagnetic interference, and incompatibility with complex automotive systems, which affects accuracy and requires recalibration with vehicle changes.
Innovation Solution
An interface device that communicates with the vehicle's on-board diagnostic (OBD) system to obtain distance data, converting it into a series of pulses compatible with the DMI, eliminating the need to tap into the VSS signal and allowing the DMI to function in any OBD-fitted vehicle, while also providing a processor for signal interpretation and translation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transmission sensor is tapped into the VSS signal to measure vehicle speed and distance, then precise speed and distance measurements can be obtained, but the installation becomes complex and difficult due to varying cable locations and routing requirements
Solution Approach 1:
The patent uses an intermediary device (the sensor kit with pulse generator) that connects to the readily accessible OBD-II port rather than requiring direct tapping into the VSS signal cable. This intermediary approach maintains measurement precision while simplifying installation by eliminating the need to locate and access the VSS cable in hard-to-reach areas under the hood or along the transmission.
Solution Approach 2:
The sensor kit is designed to be universally compatible with multiple vehicle makes and models by connecting to the standardized OBD-II port rather than vehicle-specific VSS cables. This universal interface approach maintains precise speed and distance measurements across different vehicles while eliminating the need for custom installation procedures for each vehicle type.
2Ease of operation
If the VSS signal cable is routed through the firewall to access the DMI in the vehicle cab, then the DMI can be used inside the vehicle, but the wiring becomes susceptible to electromagnetic interference and corrosion
Solution Approach 1:
The patent introduces an intermediary processing unit that connects to the OBD-II port and generates pulse signals based on speed data received from the vehicle's computer. This intermediary device can be positioned inside the vehicle cab away from EMI sources while still receiving accurate speed data digitally from the OBD-II port, eliminating the need to route analog VSS cables through the firewall where they are exposed to electromagnetic interference and corrosion.
Solution Approach 2:
The patent replaces the mechanical/electrical analog VSS cable routing system with a digital data transmission system using the OBD-II port. Instead of physically routing the VSS signal cable through the firewall, the system uses digital communication protocols to transmit speed data from the vehicle's computer to the pulse generator inside the cab, eliminating susceptibility to electromagnetic interference and corrosion.
3Reliability
If the transmission sensor is installed under the hood or along the transmission to access the VSS signal, then the VSS signal can be obtained, but the installation requires drilling holes through the firewall and becomes time-consuming
Solution Approach 1:
The patent uses an intermediary connection to the OBD-II port that provides access to vehicle speed data without requiring physical installation near the transmission or drilling holes through the firewall. The OBD-II port serves as an intermediary access point that is readily available in the vehicle's interior, eliminating time-consuming installation steps while maintaining reliable speed data acquisition.
Solution Approach 2:
The patent leverages the pre-existing OBD-II port infrastructure that is already installed in modern vehicles, eliminating the need for preliminary installation steps such as drilling holes through the firewall or routing cables under the hood. The OBD-II port is already positioned in an accessible location, allowing for rapid deployment of the sensor kit without time-consuming modifications to the vehicle structure.
4Measurement precision
If the VSS signal is tapped into using a separate wire, then the DMI can receive speed data, but the wire installation is prone to corrosion and requires careful routing to avoid interference with ABS braking systems
Solution Approach 1:
The patent uses the OBD-II port as an intermediary connection that provides a shielded and protected pathway for speed data transmission. Instead of installing separate wires that are susceptible to corrosion and interference, the system uses the existing OBD-II communication infrastructure, which is designed to be protected from environmental factors and does not interfere with other vehicle systems like ABS braking.
Solution Approach 2:
The patent replaces the physical wire-tapping method with digital data communication through the OBD-II port. Instead of installing additional electrical wires that require careful routing and are susceptible to corrosion, the system uses digital protocols to transmit speed data, eliminating the reliability issues associated with physical wire installation while maintaining accurate speed data transmission.
5Adaptability or versatility
If a sensor kit is installed in each vehicle to interface with the VSS signal, then the DMI can be used in that vehicle, but compatibility with modern automotive systems becomes difficult due to increasing system complexity and signal multiplexing
Solution Approach 1:
The patent achieves universal compatibility across modern vehicles by connecting to the standardized OBD-II port, which is present in all vehicles manufactured after 1996. This universal interface allows the sensor kit to work with diverse automotive systems without requiring vehicle-specific modifications, overcoming the complexity of different VSS cable locations, routing, and signal configurations across various makes and models.
Solution Approach 2:
The patent uses the OBD-II port as a universal intermediary that abstracts away the complexity of underlying automotive systems. Rather than requiring direct access to vehicle-specific VSS signals with varying locations and configurations, the system communicates through the standardized OBD-II interface, which handles the complexity of different automotive architectures internally while presenting a consistent interface to the sensor kit.
Data Source
AI summary
A method and system for interfacing and communicating between an in-vehicle device such as an on board diagnostic (OBD) system and an existing distance measurement instrument (DMI) are provided. In one embodiment, the interface sends a plurality of vehicle speed requests to the OBD system to obtain a plurality of vehicle speed measurements, uses the plurality of vehicle speed measurements and time stamps associated therewith to compute a distance travelled during a time interval, converts the distance travelled to a series of pulses, and sends the series of pulses to the DMI.