PEPS Infrared Detection for Battery Power Conservation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current passive entry passive start (PEPS) systems in vehicles deplete battery power quickly due to continuous transmission of low-frequency pulsed signals for polling key fobs, limiting the duration they can operate before needing to enter a sleep mode.
Innovation Solution
Incorporating an infrared detector to identify living things approaching the vehicle, allowing the system to initiate polling signals only when a user is detected, reducing power consumption by using lower current infrared detection and potentially switching to VHF-UHF band signals for further power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous low-frequency pulsed signals are transmitted for polling key fobs, then the PEPS system can detect approaching users reliably, but battery power is depleted quickly
Solution Approach 1:
The system transmits low-frequency pulsed polling signals periodically at predetermined pulse rates instead of continuously. The pulse width and pulse rate are optimized to detect approaching users while conserving battery power, allowing the system to operate for extended periods before requiring sleep mode.
Solution Approach 2:
An infrared detector is introduced as an intermediary component that continuously monitors for living things (users) approaching the vehicle. This infrared detection system operates at lower power consumption and triggers the high-power low-frequency polling signals only when a user is detected in proximity, significantly reducing overall battery drain while maintaining reliable detection.
2Length of stationary object
If the vehicle transmits polling signals at greater distances, then user detection range is improved, but more current is required
Solution Approach 1:
The polling signals are transmitted as periodic pulses with optimized pulse width and pulse rate. This periodic transmission allows the signal to reach greater distances while consuming less average current compared to continuous transmission at the same power level.
Solution Approach 2:
The system replaces direct long-range low-frequency polling with a two-stage approach: first using infrared detection (optical/thermal field) for initial user detection, then using low-frequency polling (electromagnetic field) for authentication. This substitution allows effective operation at greater distances without requiring excessive current for the low-frequency signals.
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
Extends the operational time of the PEPS system by reducing battery drain, enabling longer periods of operation without needing to enter sleep mode and allowing for more efficient direction-based door opening and vehicle function activation.
Implementation Method 1
using an infrared detector on the vehicle to identify a living thing in the vicinity of the vehicle
Implementation Method 2
using a low frequency (LF) pulsed signal to poll the key fob
Data Source
AI summary
A system and method for providing a polling signal transmitted from a vehicle that is received by a key fob held by an authorized user of the vehicle as the user approaches the vehicle. When the key fob receives the polling signal, it will automatically transmit a command signal back to the vehicle for some vehicle operation to be performed. Battery power is conserved on the vehicle by using an infrared detector to first detect whether a living thing is in proximity to the vehicle prior to the vehicle transmitting the polling signal.