Self-Powered Tire Pressure Sensor Using Electromechanical Energy Harvesting
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Solution Overview
Problem
Existing tire pressure monitoring systems face challenges such as limited battery life, large size, high cost, and accuracy issues, particularly with indirect measurement methods requiring frequent recalibration and being prone to damage during tire changes.
Innovation Solution
A self-powered tire pressure sensor system where sensors are integrated within the inflatable tire portion, using a mechanical energy harvester to convert collisions into electrical potential, enabling wireless transmission of pressure data without external wires or bulky components, and an alternative embodiment using electromagnetic energy for power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a battery is used to power the wireless tire pressure sensor, then the sensor can transmit data wirelessly, but the battery life is limited and the device size increases
Solution Approach 1:
The sensor system generates its own power through electromagnetic induction by utilizing the relative motion between the sensor mounted on the tire and the magnetic elements in the wheel assembly. This self-powered approach eliminates the need for batteries, resolving the contradiction between battery life and device size.
Solution Approach 2:
The patent replaces the chemical energy storage system (battery) with an electromagnetic energy conversion system. The sensor uses electromagnetic induction to convert mechanical motion into electrical energy, substituting a mechanical/physical process for a chemical one, thereby eliminating battery constraints.
2Reliability
If a wired connection is used to power the tire-mounted sensor, then continuous power supply is achieved, but making a reliable continuous-path connection is difficult
Solution Approach 1:
The patent replaces the mechanical wired connection system with an electromagnetic field-based power transmission system. Power is transmitted wirelessly through electromagnetic induction between the wheel assembly and the sensor, eliminating the need for physical connectors and reducing connection complexity while maintaining reliability.
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary medium to transfer power from the wheel assembly to the sensor without direct physical contact. This intermediary approach allows power transmission through the tire structure without requiring reliable wired connections.
3Measurement precision
If direct measurement sensors are mounted on the tire, then accurate pressure reading is achieved, but the sensors are subject to damage during tire removal and fitting procedures
Solution Approach 1:
The patent combines the pressure sensor with the wheel assembly structure, integrating it into a protected location within the wheel rather than mounting it externally on the tire. This integration protects the sensor from damage during tire removal and fitting while maintaining measurement accuracy through proximity to the tire pressure.
Solution Approach 2:
The patent provides protective housing and mounting structures for the sensor within the wheel assembly before the tire is installed. This pre-protective measures approach shields the sensor from mechanical damage during subsequent tire handling operations.
4Ease of manufacture
If indirect monitoring systems are used, then the system is cheaper and easier to implement, but they are not as accurate and require frequent recalibration
Solution Approach 1:
The system uses existing wheel speed sensors and vehicle motion data to generate power for the pressure measurement, eliminating the need for separate power sources or complex calibration systems. This self-powered approach enables direct measurement accuracy at lower cost by utilizing already-present mechanical energy in the wheel assembly.
Solution Approach 2:
The patent makes the wheel assembly serve multiple functions: it provides structural support, generates power through electromagnetic induction, and houses the pressure sensing mechanism. This multi-functionality eliminates the need for separate calibration systems required by indirect monitoring methods.
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 system provides accurate, long-lasting, and cost-effective tire pressure monitoring without the need for recalibration, as sensors are small, robust, and can be easily installed or replaced, ensuring continuous monitoring of tire pressure both during motion and at rest.
Implementation Method 1
The power circuit converts mechanical acceleration experienced by the device into electrical potential using an electromechanical transducer
Implementation Method 2
the power circuit includes a means to convert electromagnetic (EM) energy received by the wireless receiver into electrical potential
Data Source
AI summary
A self-powered tire pressure sensor device. The sensor device includes a power circuit, an air pressure measurement sensor, a signal circuit and a wireless transmission circuit. The power circuit converts mechanical acceleration experienced by the device into electrical potential using an electromechanical transducer. Mechanical acceleration due to collisions between the mobile sensor device and the wall of the tire while the tire is in motion cause the transducer to emit a small electrical charge. An electrical potential storage element in the power circuit accumulates and stores the charge as electrical potential. Alternatively the power circuit receives and converts electromagnetic energy into electrical potential. The electrical potential powers an air pressure measurement sensor within the tire. A signal circuit and wireless transmission circuit transmit the measurement to a chassis-mounted receiver, which makes the tire pressure measurement available to systems remote from the tire.