External TPMS Sensor Miniaturization With Low-Power RF Transmission
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Solution Overview
Problem
Existing TPMS sensors for heavy-duty trucks face challenges in achieving a long service life and miniaturization while maintaining stable data transmission, as they consume high power and interfere with tire dynamics due to large size, and their installation methods compromise safety and increase labor costs.
Innovation Solution
The TPMS sensor employs a helical antenna, a 1225 button cell, and various power-saving measures such as increased communication rate, reduced sampling period, decreased data frames, and RF output power, along with an optional LNA circuit to improve sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a large cell is used to ensure sufficient power capacity, then the service life is extended, but the size of the TPMS sensor increases
Solution Approach 1:
The patent changes the communication parameters by increasing the communication rate from traditional low rates (e.g., 9.6 kbps) to higher rates (e.g., 19.2 kbps or higher), which reduces the transmission time for each data frame. This parameter change allows the system to achieve the same data transmission stability with a smaller cell capacity, thereby reducing sensor size while maintaining acceptable service life
Solution Approach 2:
The patent implements periodic data transmission with optimized intervals, transmitting data frames at controlled rates rather than continuously. By adjusting the communication rate and transmission frequency, the system reduces total power consumption over the service period, enabling the use of smaller cells that would otherwise be insufficient for long-term operation
2Reliability
If a low communication rate is used to reduce power consumption per transmission, then the transmission stability improves, but the time to send each frame of data increases
Solution Approach 1:
The patent changes the communication rate parameter to higher values (e.g., 19.2 kbps or above), which inherently reduces the time required to transmit each data frame. This parameter change is compensated by optimizing other system parameters such as sampling frequency and transmission interval, thereby maintaining transmission stability despite the faster communication rate
3Reliability
If the number of data frames transmitted every time is increased to guarantee transmission stability, then the reliability improves, but the power consumption increases
Solution Approach 1:
The patent changes the communication rate parameter to higher values, which allows the system to transmit the same amount of data with fewer frames or in shorter time. This reduces the total transmission time and consequently the power consumption, while maintaining transmission stability through the increased robustness of each individual frame transmission at higher rates
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
This design reduces power consumption, miniaturizes the sensor, ensures stable data transmission, and maintains dynamic balance, meeting market demands for longevity and ease of installation without compromising safety.
Implementation Method 1
a helical antenna and a 1225 cell
Implementation Method 2
a 1225 cell, and is installed outside a tire of a vehicle
Data Source
AI summary
An external TPMS sensor for heavy-duty trucks comprises a helical antenna and a 1225 cell, and is installed outside a tire of a vehicle; and system power consumption is reduced by increasing the communication rate of the TPMS sensor, and/or decreasing the sampling period, and/or decreasing the number of data frames transmitted every time, and/or decreasing RF output power, and/or disposing an LNA circuit at an input terminal of a corresponding receiver antenna. The requirement of the TPMS sensor for a long service life is met by reducing system power consumption; the helical antenna, the matching network, and the 5 dBm chip for outputting power are used to realize miniaturization of the TPMS sensor; and the 1225 cell is used, which, compared with traditional TPMS sensors, allows the diameter of the TPMS sensor to be reduced by about 8 mm and the weight of the TPMS sensor to be reduced by over ⅓, such that miniaturization of the TPMS sensor is further realized.