초록 ▼

Disclosed herein is an evaporative emission control system which can properly control the ratio between a tank purge amount and a canister purge amount to realize quick pressure reduction in a fuel tank and ensuring the storage capacity of a canister in a well balanced fashion. A target pressure in

Disclosed herein is an evaporative emission control system which can properly control the ratio between a tank purge amount and a canister purge amount to realize quick pressure reduction in a fuel tank and ensuring the storage capacity of a canister in a well balanced fashion. A target pressure in controlling the pressure in the fuel tank at a negative pressure and a detected pressure in the fuel tank are compared with each other. When the difference between the target pressure and the detected pressure is large, tank purge is preferentially carried out to open a tank pressure control valve. When the detected pressure is in the vicinity of the target pressure, canister purge is preferentially carried out to purge the evaporative fuel stored in the canister.

대표청구항 ▼

[ What is claimed is:] [1.]1. In an evaporative emission control system for an internal combustion engine, including a first evaporative fuel passage for connecting a fuel tank and an intake system of said internal combustion engine, a first control valve provided in said first evaporative fuel pass

[ What is claimed is:] [1.]1. In an evaporative emission control system for an internal combustion engine, including a first evaporative fuel passage for connecting a fuel tank and an intake system of said internal combustion engine, a first control valve provided in said first evaporative fuel passage for opening and closing said first evaporative fuel passage, first control means for controlling the opening degree of said first control valve so that the pressure in said fuel tank becomes lower than an atmospheric pressure, a second evaporative fuel passage for connecting said fuel tank and said intake system, a canister provided in said second evaporative fuel passage for temporarily storing evaporative fuel, a second control valve for opening and closing said second evaporative fuel passage, and second control means for controlling the opening degree of said second control valve; the improvement comprising:target pressure setting means for setting a target pressure in said fuel tank;tank pressure detecting means for detecting the pressure in said fuel tank; andthird control means for comparing said target pressure with said detected pressure in said fuel tank and controlling said first control means and said second control means according to the result of comparison between said target pressure and said detected pressure.