Ported-Enclosure Vibrating-Diaphragm Pressure Sensor

A potentially low-cost, frequency-output vibrating-diaphragm absolute pressure sensor has been developed which shows promise as an automotive manifold absolute pressure (MAP) sensor. The sensor output is stable within ± 1% of value from 25°C to 50°C and within ± 3% of value from -40°C to +80°C. It is insensitive to humidity and gasoline vapor variations. It requires no reference pressure and is therefore immune to errors due to a leaky reference chamber or material creep associated with a pressure differential.