Britannica Sources used in this answer

How do piezoelectric ceramic sensors measure pressure in automobiles?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

advanced ceramics Steps in doctor blading, a tape-casting process employed in the production of ceramic films. Ceramic powder and solvent are mixed to form a slurry, which is treated with various additives and binders, homogenized, and then pumped directly to a tape-casting machine. There the slurry is continuously cast onto the surface of a moving carrier film. The edge of a smooth knife, generally called a doctor blade, spreads the slurry onto the carrier film at a specified thickness, thereby generating a flexible tape. Heat lamps gently evaporate the solvent, and the dry tape is peeled away from the carrier film and rolled onto a take-up reel for additional processing.

In automobiles, piezoelectric ceramic sensors are primarily used to measure dynamic pressures, such as those occurring within the combustion chamber.1

These sensors function based on the piezoelectric effect, a property of certain materials—such as lead zirconate titanate (PZT)—to generate an electric voltage when subjected to mechanical stress. When pressure fluctuations deflect or compress the ceramic material, the resulting displacement of ions within the crystal lattice creates an electric polarization, producing a measurable voltage.123

Because these sensors are highly responsive and can be manufactured in small sizes, they are ideal for monitoring rapid, transient pressure changes in engine environments. This is distinct from other automotive pressure sensors, such as those in intake or exhaust manifolds, which often utilize alumina diaphragms to measure pressure through changes in capacitance rather than piezoelectricity.1