Patent ID: 7426919

Claim:
An evaporative fuel treatment apparatus comprising: a fuel tank; a purge passage that fluidly couples the intake path of an internal combustion engine and the fuel tank; a purge valve that is installed in the purge passage and controls the quantity of evaporative fuel purged from the fuel tank into the intake path; an evaporative fuel status measuring device that measures a density-based status of evaporative fuel in the fuel tank; a purge valve controlling device that controls the purge valve based on the density-based status of the evaporative fuel measured by the evaporative fuel status measuring device; and a canister that absorbs evaporative fuel produced in the fuel tank; wherein the evaporative fuel status measuring device comprises: a measuring passage with a throttle provided therein; a selector valve that is installed on one side of the measuring passage, and switches between communication between the throttle and the air, communication between the throttle and the fuel tank, and communication between the throttle and the canister; a gas flow generating device that couples to the measuring passage on the side of the throttle opposite the selector valve, and generates a gas flow; and a pressure detecting device that detects a pressure caused by the throttle and the gas flow generating device.