US Patent 7178330 Pressure detecting apparatus having solenoid valve and pressure sensor

A secondary air pressure detecting apparatus includes a solenoid valve and a pressure sensor. The solenoid valve defines a secondary air passage that introduces secondary air from the air pump into the exhaust system of an engine. The solenoid valve opens and closes the secondary air passage. The pressure sensor is integrally mounted to the solenoid valve to detect pressure of secondary air in the solenoid valve. The solenoid valve includes a coil assembly and magnetic members. The coil assembly includes a solenoid coil that generates magnetic force when the solenoid coil is energized. The magnetic members construct a magnetic circuit with the solenoid coil. The magnetic circuit is arranged outside of the secondary air passage. The pressure sensor is arranged on an opposite side of the secondary air passage with respect to the magnetic circuit.