Piezoelectric ceramic used in automobile
Piezoelectric effect in the performance of the car is, the brake pads contact the rotor in the car at low speed driving process will produce vibrations, sometimes expressed as shrill noise. This noise does not affect the performance of the brake, but would lead to unnecessary replacement brake pads and pads, installing the silencing material and other components used to eliminate noise.
When the brake piston is mounted in the vehicle in a simple piezoelectric ceramic actuator applied with the "dithering" frequency blocks to the inside of the brake support plate fir effectively suppress the generation of vibration noise is sharp, so that it can brake the temperature and humidity change play a role in the case of normal wear and tear of the system. Since no logic system or the detector is mounted to determine the appropriate control frequency, this device is much simpler in structure, the elements required is relatively small.
Piezoelectric ceramics can be used as a piezoelectric ceramic automotive knock sensor, an ultrasonic sensor, an acceleration sensor and other categories. Knock sensor consists of a piezoelectric ceramic piezoelectric ceramic oscillator, metal sheets, gaskets, metal shell. Vibration is proportional to the charge in the cylinder of the engine generated by a piezoelectric transducer, the generated voltage by the shield wire into the electronic control unit, thereby detecting the voltage generated by the vibration around 7kHz.
Electronic control means determines the knock intensity based on the size of this voltage, the timely response of delayed ignition timing correction or eliminate knocking, the engine near the knock highest thermal efficiency, fuel consumption of the ignition timing at least work knock-free operation state ensure that the engine power to the greatest possible economic indicators running.
Ultrasonic sensors for automotive anti-collision alarm reversing device, also known as ultrasonic parking sensor or reversing sonar systems, especially for the lengthened loading vehicles, contained significant trucks, mining vehicles and other large vehicles. Ultrasonic sensors typically change from aluminum alloy, piezoelectric ceramic energy converter, sound-absorbing material, wire electrodes, having a characteristic broad horizontal and the vertical direction is limited directionality, the use of lead zirconate titanate PZT piezoelectric ceramics on the principle and inverse piezoelectric effect and the mechanical energy between the energy conversion, both an electrical signal applied to the piezoelectric ceramics, the mechanical vibrations will produce ultrasonic waves, when the ultrasonic propagation obstacles encountered in the air is immediately reflected back on the way, the role of in its ceramics, then there will be an electrical signal output by the data processing time difference ranging, calculations show the distance and dangerous obstacle when the car collided with the police, can accurately detect rear of the car and the motorist's blind spot tiny obstacle perspective physical, practical quite strong.
In order to obtain high emission efficiency and receiving sensitivity, and transmitting and receiving together the whole ultrasonic sensor is the mainstream product in the market, with high emission efficiency, and the receiving sensitivity of a sharp directivity. An ultrasonic probe with a certain angle and range, can cover the entire area of the rear of the car. Electronically controlled suspension system for automotive direct measurement of ultrasonic sensors chassis with the road distance being developed. Ultrasonic sensors are also used for air flow meter, detects the size of the engine intake air.
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Piezoelectric ceramic accelerometer sensor for automotive airbag system, the inertia of the inertial force of the collision will be formed by shearing force acting on the piezoelectric ceramic body, whereby the occurrence of charge and the voltage proportional to the acceleration, high precision and high reliability. The two piezoelectric ceramic sheets is bound by the inside of the common electrodes connected in series to form a secondary structure, installation and formed in the direction of movement of the cantilever beam, and the thickness of the peripheral circuit in the integrated production of a housing to detect low or automobile momentary high-speed collision strength, converted into electrical signals output to meet the diagnostic algorithm to control a variety of requirements to ensure the strength of the big crash, the airbag accurate and timely turn, improve vehicle safety performance.
