Series Interlock System with Unique Impedance Values for Breach Identification
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Solution Overview
Problem
Conventional series interlock systems in motor vehicles fail to accurately identify individual breached locations, leading to inefficiencies in diagnosis and potential misdiagnosis due to multiple possible states and interference from other conditions like open connectors or broken wires.
Innovation Solution
A series interlock system with safety interlocks having unique impedance values, where a control module measures and compares overall electrical characteristics to a data table to determine which interlock is breached, allowing for precise identification of open interlocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional series interlock systems are used with multiple access points, then the system can prevent access to high voltage when unsafe conditions are detected, but the controller cannot identify the specific location of breached interlocks, leading to considerable diagnostic time and effort
Solution Approach 1:
The patent applies the principle of using distinct electrical characteristics (analogous to color changes) by assigning unique impedance values to each interlock switch. When a switch opens, its unique impedance value changes the overall electrical characteristic of the series loop, allowing the controller to identify which specific interlock is breached by comparing the measured characteristic against stored reference values, thereby eliminating diagnostic time while maintaining safety reliability
Solution Approach 2:
The patent implements parameter changes by varying the impedance value of each interlock switch in the series loop. Each switch has a distinct impedance parameter that creates a unique electrical fingerprint for each possible breach location. The controller measures the overall electrical characteristic and compares it to a data table of expected values to quickly identify which specific interlock is open, resolving the contradiction between maintaining safety and reducing diagnostic time
2Reliability
If conventional series interlock systems are used with multiple access points, then the system can detect unsafe conditions, but the controller only detects one state corresponding to all interlocks being closed without indicating breach locations
Solution Approach 1:
The patent uses distinct electrical characteristics (analogous to color changes) by assigning unique impedance values to each interlock switch. When any switch opens, the overall electrical characteristic of the series loop changes in a specific way that corresponds to which switch is open. The controller measures this characteristic and compares it against stored reference values to identify the specific breach location, thereby preserving complete information about which interlock is breached while maintaining safety detection reliability
Solution Approach 2:
The patent changes the impedance parameter of each individual interlock switch to create unique electrical signatures. This allows the system to detect not only that an interlock is breached but also precisely which one is breached, eliminating information loss about breach location while maintaining the reliability of safety condition detection
3Measurement precision
If separate interlock loops are run to each interlock to enable identification of breached locations, then individual breach identification is possible, but added costs, space, weight, and installation time are required due to many additional wires
Solution Approach 1:
The patent merges multiple separate measurement functions into a single series loop configuration. Instead of requiring separate wires to each interlock, the system combines all interlock switches into one series circuit where the unique impedance value of each switch provides the identification information. This single loop approach achieves precise breach location identification while dramatically reducing wiring complexity, space, weight, and installation requirements compared to multiple separate loops
Solution Approach 2:
The single series interlock loop serves multiple functions simultaneously: it provides safety interlocking, enables precise identification of breach locations, and reduces wiring complexity. The unique impedance values assigned to each switch allow the same series loop structure to perform both safety protection and diagnostic identification functions, eliminating the need for additional separate measurement circuits
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and accurate identification of breached interlocks, reducing diagnostic time and effort by providing a unique impedance value for each combination of open and closed states, thus improving the reliability of interlock system analysis.
Implementation Method 1
A series interlock loop having an overall electrical characteristic. The series interlock loop including a first safety interlock with a first switch coupled in parallel with a first impedance value. A second safety interlock is electrically coupled in series with the first safety interlock. The second safety interlock includes a second switch coupled in parallel with a second impedance value.
Data Source
AI summary
A system is provided for implementing a series interlock loop. An example of the interlock system includes a series interlock loop, a data table, and a control module. The series interlock loop has an overall electrical characteristic. The series interlock loop includes first and second safety interlocks electrically coupled in series. Each interlock includes a switch coupled in parallel with an impedance value. The data table is configured to store values corresponding to the impedance values. The control module is communicatively coupled to the data table and configured to receive an indication of the overall electrical characteristic and to compare the overall electrical characteristic to the values in the data table to thereby identify an open one of the first and second safety interlocks.