Wheel Position Assignment via Signal Attenuation
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Solution Overview
Problem
Existing tire pressure monitoring systems face challenges in accurately identifying and assigning wheel positions on a vehicle due to variations in signal power caused by temperature changes and the need for extensive cabling and complex circuitry, which leads to incorrect assignments and high installation costs.
Innovation Solution
A method and device that use a wheel unit with both a transmitter and receiver to measure signal intensity and determine a characteristic value like attenuation, which is used for accurate wheel position assignment, independent of signal power variations, allowing for reliable and cost-effective identification of wheel positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal power is used for wheel position assignment, then the assignment can be performed, but temperature variations cause incorrect assignments due to signal power changes
Solution Approach 1:
The patent changes the measurement parameter from signal power to signal attenuation. Instead of measuring the absolute power of the received signal which varies with temperature, the system measures the attenuation (loss) of the signal along the transmission path. This parameter change makes the measurement independent of temperature-induced power variations, as attenuation represents the relative loss rather than absolute power level.
2Measurement precision
If receive antennas are installed at all tire positions with cabling to receivers, then wheel position identification is possible, but installation and maintenance costs increase significantly
Solution Approach 1:
The patent extracts the receiving function from multiple distributed receive antennas and consolidates it into a single receive antenna. Instead of having receive antennas at all four wheel positions connected to receivers via cables, the system uses one central receive antenna that receives signals from all wheel units. This eliminates the need for extensive cabling and multiple receivers, dramatically reducing installation complexity and maintenance costs.
Solution Approach 2:
The single receive antenna serves multiple functions by receiving signals from all wheel units regardless of their position. The system achieves universal reception capability, where one antenna can identify and track multiple wheel positions through signal attenuation measurement, replacing the need for position-specific receive antennas.
3Measurement precision
If phase difference and polarity evaluation is used for wheel position determination, then position identification is achieved, but circuit complexity and outlay increase significantly
Solution Approach 1:
The patent replaces the complex electronic circuitry required for phase difference and polarity evaluation with a simpler signal attenuation measurement system. Instead of using circuits to analyze phase relationships and polarity, the system measures the power loss (attenuation) of the signal, which can be achieved with simpler components. This substitution dramatically reduces circuit complexity while maintaining position determination capability.
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
The solution provides a reliable and cost-effective method for assigning wheel units to their positions by using signal attenuation values, reducing the impact of signal power variations and enabling autonomous operation and collision avoidance, while allowing for efficient tire pressure monitoring and position determination.
Implementation Method 1
providing the wheel unit with a transmission unit for emitting a signal; providing an evaluation unit on the motor vehicle, and a receiving unit connected to the evaluation unit and disposed to receive the signal emitted by the wheel unit
Implementation Method 2
measuring an intensity of the signal emitted by the wheel unit in the receiving unit and communicating the intensity to the evaluation unit
Data Source
AI summary
In the automotive industry that there is an increasing need for automatic tire pressure checking systems. One challenge here is to identify the positions of the tires on the vehicle. This is normally programmed-in it at the factory at the end of the production line. The tires however mostly do not remain in the same position during their lifetime. The invention allows a wheel unit to be automatically assigned to its wheel position on the motor vehicle. To this end the attenuation along a transmit path from a wheel unit to a transmission unit or receiving unit on the motor vehicle is determined. The attenuation determined is a characteristic value which allows conclusions to be drawn about the position of a wheel unit. An assignment by way of the attenuation has the advantage that the wheel unit is independent of variations in the transmit power of the transmission unit.