Abstract: An engine exhaust purification device comprises: a selective reduction type NOx catalyst; an oxidation catalyst disposed on an upstream side of the NOx catalyst; a reducing agent adding device which adds an NOx reducing agent to an exhaust gas of an engine; a control device which controls the reducing agent adding device; and an NO2 ratio calculation device which estimates an NO2 ratio of the exhaust gas flowing into the NOx catalyst. The NO2 ratio of the exhaust gas flowing into the NOx catalyst is calculated by a catalytic reaction model where the oxidation reaction of NO in the oxidation catalyst is numerically formulated, and the NO2 ratio is reflected to calculate an amount of ammonia adsorbed on the NOx catalyst by a catalytic reaction model where a chemical reaction concerned with the reduction of NOx in the NOx catalyst is numerically formulated.

Abstract: An engine exhaust purification device comprises: a selective reduction type NOx catalyst; an oxidation catalyst disposed on an upstream side of the NOx catalyst; a reducing agent adding device which adds an NOx reducing agent to an exhaust gas of an engine; a control device which controls the reducing agent adding device; and an NO2 ratio calculation device which estimates an NO2 ratio of the exhaust gas flowing into the NOx catalyst. The NO2 ratio of the exhaust gas flowing into the NOx catalyst is calculated by a catalytic reaction model where the oxidation reaction of NO in the oxidation catalyst is numerically formulated, and the NO2 ratio is reflected to calculate an amount of ammonia adsorbed on the NOx catalyst by a catalytic reaction model where a chemical reaction concerned with the reduction of NOx in the NOx catalyst is numerically formulated.

Abstract: An exhaust gas pressure P, exhaust gas temperatures TU and TD on upstream and downstream of a DPF, a rotation speed Ne, a load Q, and an intake flow rate F as various operating conditions are read, and an amount of PM generated for short time ?t is obtained to be added to a PM deposited amount m, and thus, to obtain an initial deposited amount. Exhaust gas properties and a space velocity SV are obtained based on various operating conditions, and the PM deposited amount m after a lapse of the short time ?t is estimated from a PM deposited amount estimation equation “m=m·exp(?B·?t)” having been derived considering the exhaust gas properties and the space velocity SV. When the PM deposited amount m is equal to or more than a predetermined value, a forced regeneration processing in the DPF is executed, and thereafter, the PM deposited amount m is reset to 0.

Abstract: A combustion timing prediction method for a compression self-ignition internal combustion engine includes the steps of: specifying types of a plurality of hydrocarbon components contained in a hydrocarbon fuel and proportions of the respective types in the hydrocarbon fuel; calculating, on the basis of a temperature in a combustion chamber of the internal combustion engine, a value of a first function serving as a function of the temperature for each of the types; calculating, on the basis of the proportion and the first function relating to each of the types, a value of a second function, which is a function that increases in value in response to an increase of the value of the first function and/or the proportion, for each of the types; integrating the values of the second function relating to the respective types; and predicting, on the basis of the integrated value of the values of the second function, the combustion timing of the hydrocarbon fuel in the internal combustion engine to be steadily later as

Abstract: An exhaust gas pressure P, exhaust gas temperatures TU and TD on upstream and downstream of a DPF, a rotation speed Ne, a load Q, and an intake flow rate F as various operating conditions are read, and an amount of PM generated for short time ?t is obtained to be added to a PM deposited amount m, and thus, to obtain an initial deposited amount. Exhaust gas properties and a space velocity SV are obtained based on various operating conditions, and the PM deposited amount m after a lapse of the short time ?t is estimated from a PM deposited amount estimation equation “m=m·exp(?B·?t)” having been derived considering the exhaust gas properties and the space velocity SV. When the PM deposited amount m is equal to or more than a predetermined value, a forced regeneration processing in the DPF is executed, and thereafter, the PM deposited amount m is reset to 0.