Exhaust gas purification system for an internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorKenichi Tsujimoto
Life of this patent
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Abstract
A degree of dispersion of a reducing agent added to an exhaust gas flowing into an exhaust gas purification apparatus is controlled. Before addition fuel is added, a valve opening Vd of a flow area changing valve is changed to generate pulsation of the exhaust gas, so that addition valve vicinity exhaust gas pressure Pg varies periodically. Addition timing TMad is controlled to synchronize with extremum arrival timing TMe. High or low dispersion type addition control adds fuel at timing (CP) when the addition valve vicinity exhaust gas pressure Pg becomes a maximum value Pgmax, at timing (TP) when at a minimum value Pgmin, or at both timings (CP, TP).
Claims21
1-9. (canceled)
An exhaust gas purification system for an internal combustion engine comprising:
- an exhaust gas purification apparatus that is arranged on an exhaust passage of said internal combustion engine for purifying an exhaust gas passing through said exhaust passage, a reducing agent addition unit that is arranged on said exhaust passage at a location upstream of said exhaust gas purification apparatus for adding a reducing agent to the exhaust gas passing through said exhaust gas purification apparatus, a flow area changing unit that is arranged on said exhaust passage for changing the flow area of the exhaust gas, a pulsation generation unit that generates pulsation of the exhaust gas by changing said flow area by means of said flow area changing unit before said reducing agent addition unit adds the reducing agent to the exhaust gas, and an addition timing control unit that controls said reducing agent addition unit so as to add the reducing agent at timing at which the exhaust gas pressure in the vicinity of said reducing agent addition unit, being varied due to said pulsation of the exhaust gas, becomes in the vicinity of a maximum value and/or a minimum value.
Dependencies are inferred from the claim text.