EVAPORATED FUEL TREATING DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To improve purge control performance by a purge control valve. SOLUTION: In an idling state, low flow rate purge control is started by duty control driving the purge control valve at high frequency (S1-S3). When a purge gas flow rate calculated on the basis of purge gas concentration and a duty value reaches a desired value α, an actual driving time (a) of the purge control valve is calculated (S4-S6). A duty value B0% in low frequency driving corresponding to the actual driving time (a) of the purge control valve is calculated, and a duty value insufficient amount C% necessary for acquiring the desired value α in low frequency driving is calculated (S7). A driving frequency is changed to a low frequency, and duty of the purge control valve is controlled by changing to a duty value B obtained by adding the insufficient amount C to the duty value B0 (S8-S10). COPYRIGHT: (C)2003,JPO