| 摘要 |
Provided is an exhaust gas purification system for an internal combustion engine equipped with a selective reduction catalyst, in which discharge of reducing agent to the downstream of the selective reduction catalyst can be controlled while maintaining a high NOx reduction rate. The exhaust gas purification system comprises a storage correction input calculation section (6) for calculating an estimated value ST UREA_FB of a first storage amount, and then calculating the storage correction input G UREA_ST of urea injection amount G UREA so that the estimated value ST uREA_FB of a first storage amount coincides with a predetermined target value ST UREA_TRG of a first storage amount, a slip generation correction input calculation section (7) for calculating an slip generation correction input G UREA_SLP of urea injection amount G UREA based on an exhaust volume V EX_HAT so that a detection value NH3 CONS in an ammonia sensor coincides with a predetermined slip target value NH3 CONS_TRGT , and an adder (8) for determining a urea injection amount G UREA based on the storage correction input G UREA_ST and the slip generation correction input G UREA_SLP . |
