EV Breath Interlock Using Proximity Pilot Circuit Immobilization
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Solution Overview
Problem
The installation of breath alcohol testers in electric vehicles is not routine due to the absence of a standard ignition system like internal combustion engine vehicles, necessitating an alternative method to ensure alcohol-free operation before vehicle activation.
Innovation Solution
A breath alcohol ignition interlock system for electric vehicles using a proximity pilot circuit, comprising a normally open relay, a normally closed relay, and a resistor, which triggers a breath test upon vehicle activation and enables vehicle operation only upon a valid breath sample, utilizing the electric vehicle's low voltage ignition active circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a breath alcohol tester is installed in an electric vehicle, then alcohol-free operation can be ensured, but the installation becomes non-routine and complex due to the absence of a standard ignition system
Solution Approach 1:
The system integrates multiple functions into a single interlock device that works with electric vehicle specific circuits. The device universally handles breath testing, relay control, and integration with the proximity pilot circuit and low voltage ignition active circuit, making it adaptable to EV architecture without requiring separate systems for each function.
Solution Approach 2:
The patent introduces intermediary relays (normally open and normally closed) that mediate between the breath alcohol tester and the vehicle's electrical systems. These relays act as intermediaries to control the proximity pilot circuit and low voltage ignition active circuit, enabling indirect control since direct ignition control is not available in EVs.
2Ease of operation
If relays are used to control the ignition circuit, then vehicle activation can be controlled, but additional components increase device complexity
Solution Approach 1:
The system uses dynamic relay switching based on breath test results. The normally open relay closes to activate the vehicle when the breath test passes, while the normally closed relay opens to prevent activation when the test fails. This dynamic response enables automated control without manual intervention.
Solution Approach 2:
The control function is segmented into two separate relays with distinct roles: the normally open relay for activation control and the normally closed relay for prevention control. This segmentation allows each relay to be optimized for its specific function and simplifies the control logic by distributing responsibilities across multiple specialized components.
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 effective breath alcohol testing and vehicle immobilization in electric vehicles by leveraging the proximity pilot circuit, ensuring alcohol-free operation before vehicle activation.
Implementation Method 1
the proximity pilot circuit is connected to ground via a 400 Ohm resistor. The vehicle senses this load and becomes immobile.
Data Source
AI summary
The improved breath alcohol ignition interlock is for use with a vehicle having a proximity pilot circuit and is of the type adapted to: receive a signal when a vehicle has been enabled for activation of the drivetrain; upon receipt of that signal, trigger a breath tester to prompt for and receive a breath sample; upon receipt of a breath sample, test for alcohol; and upon a determination that the amount of alcohol in the sample is below the legal limit or other threshold, activate a relay. The improvement comprises: a normally open relay coupled to an ignition active circuit of the vehicle for activation thereby; a normally closed relay coupled to the ignition interlock for activation thereby; and a resistor, coupled to the relays in series, between the proximity pilot circuit and ground.