No-battery Research On Tire Pressure Monitoring System Based On Piezoelectric Ceramic

In order to ensure the safety of the car, people fix the Tire Pressure Monitoring System in the wheel, which also be called TPMS, can measure the pressure and the temperature in the wheel. Nowadays, most brands of the TPMS use batteries as their power. However, batteries can not be used for a long time, and the capacity of the batteries will decline while the temperature drop to a certain degree. So numerous studies have been conducted to solve this limitation, and technique of no- battery TPMS got huge development. Piezoelectric power generation is one of method.In this dissertation, a piezoelectric generator was designed as the energy resource of the TPMS. The primary content and harvest as following:1. Theoretical analysis of the piezoelectric generatorsIn this paper, the characteristic of energy export of piezoelectric vibrator has been analyzed. And several factors that would influence the energy export also have been discussed include load form, sustain form, dimension and outside load of piezoelectric vibrator. When the sustain form is cantilever, piezoelectric vibrator can generate more power. If free end load a fixed load, the output voltage of piezoelectric vibrator is direct proportional to the length, inverse proportional to the width, thickness. If the load form is vibration input, the output voltage of piezoelectric vibrator depends on the physical characteristics and the size of incentives and frequency.2. Experiments of the power generation capability of the piezoelectric vibratorThere are some differences between application and theoretical analysis about the power generation capability of the piezoelectric vibrator. So it is necessary that testing the characteristic of energy export of piezoelectric vibrator. And the main factors that would influence the energy export are demonstrated in this paper, they are sustain form and dimension of piezoelectric vibrator, mass at the end of beam, frequency and amplitude of load vibration. These rules will be the design principle of piezoelectric generators.3. Research of piezoelectric generatorsThere are two manners that piezoelectric vibrator fix to the wheel according to characteristic of motion of motor vehicle, either in tire or on the hub of the wheel. However, there are many disadvantages when piezoelectric vibrator fix in the tire. There are six different fix manners when piezoelectric vibrator is on the hub of the wheel. Then, we test and analyze the power generation capability of the piezoelectric vibrator which fix on the hub of the wheel through each manner. When piezoelectric vibrator is fixed on the hub of the wheel perpendicular to the hub of the wheel and perpendicular to the direction of rolling wheel, piezoelectric generators generating capacity is strongest.4. Research on the means of energy harvest and trial-manufacture of sample machineThere are some characteristics of piezoelectric power generation with lower electric current and higher voltage, lower energy and alternative voltage, and there is damping phenomenon with energy harvesting. Thus, some means is needed to accumulate the electricity, so as to supply power for TPMS. Three viable means of energy harvesting are submitted in this part. They are the use of secondary battery, general capacitor and super capacitor. Super capacitor was chose through the comparison, and its property was tested by experiments. Considering the characteristic and dimension of the Piezoelectric vibrator and the property of the super capacitor, we design and manufacture the piezoelectric generators sample machine which are suitable for KIA CERATO and Audi A6.In this paper, some basic laws of piezoelectric vibrator are researched, which are based on theoretical and experimental. And several piezoelectric generators which can be installed on the hub of the wheel are designed. And the best power generator has be confirmed.