Fuel evaporative emission amount detection system

摘要

A detecting system for condition of a fuel evaporative emission generated in a fuel tank, includes a pressure sensor and a three-way valve for selectively connecting the pressure sensor to atmosphere and the fuel tank. The pressure sensor is initially communicated with the atmosphere to detect an atmospheric pressure Pa (step 110), and subsequently communicated with the fuel tank to detect an internal pressure Pf of the fuel tank (step 130). Based on the atmospheric pressure Pa and the internal pressure Pf of the fuel tank, an amount EVP of the fuel evaporative emission generated in the fuel tank is derived through a map look-up against a preset map (step 150).