Motor Vehicle Lamp Diagnostic Signal via Single Line Current Summation
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Solution Overview
Problem
Current motor vehicle lighting systems require multiple diagnostic lines to detect failures in light sources, which complicates manufacturing, increases costs, and may lead to incorrect status assumptions due to line interruptions, especially with LEDs having low power consumption.
Innovation Solution
A method using a single diagnostic line to transmit a diagnostic signal that clearly identifies the status of all light sources by assigning individual diagnostic currents proportional to power series values, allowing the control unit to determine the functioning or failure of each light source, eliminating the need for complex circuit arrangements and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple diagnostic lines are used to detect failures in each light source, then the reliability of failure detection is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
Multiple diagnostic lines for individual light sources are merged into a single shared diagnostic line. The patent combines the diagnostic functions of multiple light sources (LEDs) into one common transmission path, allowing all failure status information to be conveyed through a single wire rather than requiring separate lines for each light source.
Solution Approach 2:
The single diagnostic line serves multiple functions simultaneously - it carries failure status information from multiple different light sources, enables identification of which specific light source has failed, and provides a universal diagnostic interface for the entire lighting system rather than requiring light-source-specific diagnostic paths.
2Measurement precision
If individual diagnostic lines are assigned to each light source, then the measurement precision of failure status is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The patent merges multiple individual diagnostic connections into a single shared diagnostic line, simplifying the assembly process. Instead of requiring separate wiring for each light source's diagnostic function, the design combines these into one common path that is easier to manufacture and install.
Solution Approach 2:
A current summation circuit acts as an intermediary that receives individual diagnostic currents from multiple light sources and combines them into a single composite diagnostic signal. This mediator enables precise failure identification without requiring direct separate wiring to the control unit for each light source.
3Device complexity
If a single diagnostic line is used to transmit diagnostic signals from multiple light sources, then the device complexity is reduced, but the difficulty of detecting and measuring individual light source status increases
Solution Approach 1:
The patent assigns unique local characteristics (specific current values) to each light source's diagnostic current contribution. By giving each LED a distinct current magnitude that corresponds to its identity, the system enables the control unit to decode which specific light source has failed by analyzing the composite current signal's characteristics.
Solution Approach 2:
The system uses parameter changes in the diagnostic current - specifically varying the current magnitude according to a power series relationship - to encode information about individual light source status. The control unit detects failures by measuring changes in the total diagnostic current and correlating these changes with the known current values assigned to each light source.
4Use of energy by moving object
If LED power consumption is reduced for energy efficiency, then the use of energy is improved, but the reliability of detecting LED status deteriorates
Solution Approach 1:
The patent introduces a current summation circuit as an intermediary that amplifies and consolidates the small diagnostic currents from low-power LEDs. This mediator circuit enables reliable detection of the combined diagnostic signal even though individual LED diagnostic currents are minimal, solving the problem of detecting status from low-power components.
Solution Approach 2:
The system replaces direct electrical measurement of individual LED status with an optical/electrical conversion approach where diagnostic information is transmitted through current modulation. The control unit detects LED status by measuring current changes rather than directly monitoring each LED's operational state, enabling reliable detection despite low power consumption.
Data Source
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AI summary
A method for generating a diagnostic signal (Idiag) from a motor vehicle lamp (01) and a corresponding motor vehicle lamp (01) are described. The lamp has several light sources (02, 03, 04, 05, 06) each comprising at least one light source (10) and intended to fulfill at least one lighting function. At least two of these light sources are equipped with a fault detection device (11) for one or more of their light sources (10). The diagnostic signal (Idiag) is transmitted via a single diagnostic line (07) and indicates the proper functioning (corresponding to a good state) and/or the improper functioning (corresponding to a bad state) of one or more of the light sources (02, 03, 04, 05, 06) of the motor vehicle lamp (01) intended to fulfill at least one currently required lighting function. The signal uniquely assigns good and bad states to these light sources (02, 03, 04, 05, 06).For this purpose, the method provides a diagnostic signal (Idiag) in the form of a diagnostic current, which corresponds to a sum diagnostic current from one or more individual diagnostic currents. Each fault detection (11) of a light source (02, 03, 04, 05, 06) equipped with a fault detection (11) is assigned an individual diagnostic current of a specified current intensity.Furthermore, each sum of any combination of individual diagnostic currents assigned to the fault detections (11) results in a total diagnostic current of such a magnitude that it allows a clear conclusion to be drawn about those light sources (02, 03, 04, 05, 06) intended to fulfill one or more currently required lighting functions of the vehicle light (01) that are in good condition, as well as about those light sources (02, 03, 04, 05, 06) intended to fulfill one or more currently required lighting functions of the vehicle light (01) that are in bad condition.The motor vehicle lamp (01) has corresponding allocation means (13) which assign a unique individual diagnostic current to each fault detection (11), whereby the sum of any different combinations of individual diagnostic currents results in sum diagnostic currents of different current strengths which, when output as a diagnostic signal (Idiag), allow a unique identification of lamp sources (02, 03, 04, 05, 06) in good condition and lamp sources (02, 03, 04, 05, 06) in bad condition, as determined on the basis of the fault detections (11).