Two Axis Antenna TPMS Sensor Localization
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Solution Overview
Problem
Combining SMART entry and TPMS systems with 125 KHz LF antennas results in difficulties in providing instantaneous tire pressure data at ignition, due to antenna placement issues, power drain, and interference with vehicle radio systems, leading to inaccurate localization of tire sensors.
Innovation Solution
Implementing a vehicle entry/tire pressure management system with strategically positioned LF antennas and an ECU that transmits LF fields from multiple antennas to wake up tire sensors, using unique header formats to conserve power and prevent interference, while also determining sensor locations based on received identification signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If LF antennas are mounted in wheel wells to wake up TPMS sensors, then tire pressure data can be obtained instantaneously at ignition, but the system complexity and number of antennas increase
Solution Approach 1:
The patent combines SMART entry and TPMS functions into a single LF antenna system. The same LF antenna that wakes up TPMS sensors also serves as a SMART entry antenna, eliminating the need for separate antennas for each function and reducing overall system complexity while maintaining instantaneous tire pressure data acquisition
2Device complexity
If LF antennas are combined for SMART entry and TPMS, then the number of antennas is reduced, but accurate localization of tire sensors becomes difficult
Solution Approach 1:
The patent implements a feedback mechanism where the ECU receives identification signals from TPMS sensors and uses signal strength information to determine which antenna woke up each sensor. This feedback loop enables accurate localization of tires even with combined antennas, as the system can trace which antenna received the strongest response from each sensor
3Reliability
If strong LF fields are transmitted to wake up tire sensors, then sensor detection is improved, but interference with vehicle radio systems occurs
Solution Approach 1:
The patent uses periodic transmission of LF wake-up signals rather than continuous transmission. The ECU transmits LF fields at specific intervals to wake up TPMS sensors, reducing the overall exposure time and minimizing interference with vehicle radio systems while maintaining reliable sensor detection through repeated periodic attempts
4Adaptability or versatility
If LF antennas are mounted on vehicle doors for SMART entry, then keyless entry functionality is achieved, but tire sensor localization becomes problematic when doors are open
Solution Approach 1:
The patent implements dynamic antenna selection based on door position. When doors are closed, door-mounted antennas are used for both SMART entry and TPMS. When doors are open, the system dynamically switches to use body-mounted or wheel well-mounted antennas for TPMS sensor detection, ensuring accurate tire localization regardless of door position while maintaining keyless entry functionality
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 accurate and timely presentation of tire pressure data at ignition, reduces power consumption, and minimizes interference with vehicle radio systems by optimizing antenna placement and signal processing.
Implementation Method 1
The TPMS control unit sends a signal to the LF antenna to transmit an LF field to wake up the TPMS sensor
Data Source
AI summary
A vehicle entry/tire pressure monitoring system for a vehicle includes an ECU, LF antennas mounted on the vehicle and being in communication with the ECU, and tire sensors mounted in, on or adjacent respective tires of the vehicle. Each LF antenna is configured to transmit an LF tire sensor wake up field and a SMART entry LF search field to wake up a portable transmission/reception unit for keyless entry of the vehicle tire sensor. Each tire sensor includes a two-axis receiver antenna and an RF transmitter configured to transmit an RF signal. Each two-axis receiver antenna is configured such that a first axis of the two-axis antenna is configured to detect a respective LF field transmitted by one of the LF antennas and a second axis of the two-axis antenna is configured to detect a respective LF field transmitted by another of the LF antennas.