Hydrocarbon deposition amount estimation device, hydrocarbon deposition amount estimation method, control device, and exhaust gas purification system

A hydrocarbon deposition amount estimation device comprising:

• a hydrocarbon deposition amount estimation computer unit that estimates a deposition amount of hydrocarbons deposited in an exhaust gas purification device of an internal combustion engine equipped with an oxidation catalyst based on at least a first measured value corresponding to an intake air temperature of the internal combustion engine, a second measured value corresponding to a temperature of a cooling liquid of the internal combustion engine, and a third measured value corresponding to an exhaust gas flow rate of the internal combustion engine,
• a storage computer unit that stores first correspondence information representing a correspondence of the third measured value, a fourth measured value corresponding to a temperature inside the exhaust gas purification device, and an increase amount of hydrocarbons deposited in the exhaust gas purification device, according to environmental conditions of the internal combustion engine, wherein
• the hydrocarbon deposition amount estimation computer unit estimates the increase amount based on the environmental conditions of the internal combustion engine determined based on the first measured value and the second measured value, the third measured value, the fourth measured value, and the first correspondence information when estimating the deposition amount, and
• the environmental conditions include factors related to at least one of injection timing, rail pressure, pilot injection amount, pilot injection period, and post injection amount, which are related to fuel injection control of the internal combustion engine,
• whereby hydrocarbon deposition amount is estimated more accurately based on the first through the fourth measured values than based on an engine rotation speed, an injected fuel mass, an intake air mass, and an ambient temperature as parameters, such that a time until a control that involves fixing an engine rotation speed is started is delayed and as a result, a time during which a normal operating state is continued can be extended.