| 摘要 |
PROBLEM TO BE SOLVED: To increase response properties in temperature control of a denitration catalyst, to increase exhaust gas NOx reduction effect, and to maintain soundness of the denitration catalyst, with a simple and inexpensive structure.SOLUTION: An internal combustion engine includes: a diesel engine with a supercharger; a denitration catalyst reducing nitrogen oxides contained in exhaust gas thereof; a bypass part with a bypass valve, bleeding some of the exhaust gas and sending it to the denitration catalyst while bypassing the supercharger; and a control part controlling an opening of the bypass valve. The control part executes denitration catalyst temperature estimation control A calculating an estimation value of a total flow rate of the exhaust gas on the basis of a rotation speed of the diesel engine, a fuel supply amount, and an intake air flow rate, calculating, on the basis of the calculated estimation value, the opening of the bypass valve, an estimation value of an operation point of the supercharger, and an estimation value of an inlet temperature of the denitration catalyst from a pre-programmed map, and setting the opening of the bypass valve so that the estimation value T of the inlet temperature of the denitration catalyst falls within a range T-Tpreferable for the denitration catalyst. |
