An amount of deposition of intramural PM in a particulate filter is estimated with a high degree of accuracy. A controller obtains, as a correlation between a reference value of an intramural PM deposition amount and an oxygen storage capacity of the catalyst, a change over time of an oxygen storage capacity of the catalyst according to a change of a filter PM deposition amount in a period of time from a point in time at which the filter PM deposition amount is substantially zero to a point in time at which the oxygen storage capacity of the catalyst, which becomes larger according to an increase of the filter PM deposition amount, reaches a maximum value. Further, the controller estimates a current intramural PM deposition amount based on a current oxygen storage capacity of the catalyst and the correlation.

An amount of deposition of intramural PM in a particulate filter is estimated with a high degree of accuracy. A controller obtains, as a correlation between a reference value of an intramural PM deposition amount and an oxygen storage capacity of the catalyst, a change over time of an oxygen storage capacity of the catalyst according to a change of a filter PM deposition amount in a period of time from a point in time at which the filter PM deposition amount is substantially zero to a point in time at which the oxygen storage capacity of the catalyst, which becomes larger according to an increase of the filter PM deposition amount, reaches a maximum value. Further, the controller estimates a current intramural PM deposition amount based on a current oxygen storage capacity of the catalyst and the correlation.

A rich-wait-time threshold value is set based on the NOx discharge amount per unit time discharged from an internal combustion engine. When the elapsed time, i.e. either the elapsed engine operation time since rich control was performed on a lean NOx trap catalyst device, or the elapsed engine operation time since the engine was started, becomes equal to or greater than the rich-wait-time threshold value, a determination that the rich control be started is added as a necessary condition for starting the rich control. Accordingly, an exhaust gas purification system for an internal combustion engine, an internal combustion engine, and an exhaust gas purification method for an internal combustion engine are provided, with which the execution timing of the rich control for recovering the NOx occlusion capacity of the lean NOx trap catalyst device is rendered more appropriate, and thus NOx reduction is performed with little fuel consumption deterioration.

A rich-wait-time threshold value is set based on the NOx discharge amount per unit time discharged from an internal combustion engine. When the elapsed time, i.e. either the elapsed engine operation time since rich control was performed on a lean NOx trap catalyst device, or the elapsed engine operation time since the engine was started, becomes equal to or greater than the rich-wait-time threshold value, a determination that the rich control be started is added as a necessary condition for starting the rich control. Accordingly, an exhaust gas purification system for an internal combustion engine, an internal combustion engine, and an exhaust gas purification method for an internal combustion engine are provided, with which the execution timing of the rich control for recovering the NOx occlusion capacity of the lean NOx trap catalyst device is rendered more appropriate, and thus NOx reduction is performed with little fuel consumption deterioration.

A system of controlling an engine provided with a dual continuously variable valve duration device may include the engine including a combustion chamber, an intake valve, an ignition switch provided in the combustion chamber, and an exhaust valve, the CVVD provided to adjust an intake duration of the intake valve and an exhaust duration of the exhaust valve, a warm-up catalytic converter (WCC) including a three-way catalyst (TWC) for purifying hydrocarbons, carbon monoxide, nitrogen oxides contained in the exhaust gas downstream of the engine, a Hydrocarbon (HC) trap disposed downstream of the warm-up catalytic converter for adsorbing and removing the hydrocarbons contained in the exhaust gas, an electrically heated catalyst disposed downstream of the HC trap and provided with a heating device, a three-way catalyst (TWC) disposed downstream of the electrically heated catalyst for purifying hydrocarbons, carbon monoxide, and nitrogen oxides contained in the exhaust gas, and a controller for adjusting an ignition timing of the ignition switch, the intake duration and the exhaust duration based on a driving condition of the vehicle.

A system of controlling an engine provided with a dual continuously variable valve duration device may include the engine including a combustion chamber, an intake valve, an ignition switch provided in the combustion chamber, and an exhaust valve, the CVVD provided to adjust an intake duration of the intake valve and an exhaust duration of the exhaust valve, a warm-up catalytic converter (WCC) including a three-way catalyst (TWC) for purifying hydrocarbons, carbon monoxide, nitrogen oxides contained in the exhaust gas downstream of the engine, a Hydrocarbon (HC) trap disposed downstream of the warm-up catalytic converter for adsorbing and removing the hydrocarbons contained in the exhaust gas, an electrically heated catalyst disposed downstream of the HC trap and provided with a heating device, a three-way catalyst (TWC) disposed downstream of the electrically heated catalyst for purifying hydrocarbons, carbon monoxide, and nitrogen oxides contained in the exhaust gas, and a controller for adjusting an ignition timing of the ignition switch, the intake duration and the exhaust duration based on a driving condition of the vehicle.

A catalyst temperature estimation device that estimates a temperature of a catalyst provided in an exhaust passage of an internal combustion engine includes a storage device and processing circuitry. The storage device stores mapping data that specifies a mapping that uses multiple input variables to output an estimation value of the temperature of the catalyst. The multiple input variables include at least one variable of an ambient temperature variable or an excess amount variable. The multiple input variables further include a fluid energy variable, which is a state variable related to energy of fluid flowing into the catalyst, and a previous cycle value of the estimation value of the temperature of the catalyst. The processing circuitry is configured to execute an acquisition process, a temperature calculation process, and an operation process. The mapping data includes data that is learned through machine learning.

A catalyst temperature estimation device that estimates a temperature of a catalyst provided in an exhaust passage of an internal combustion engine includes a storage device and processing circuitry. The storage device stores mapping data that specifies a mapping that uses multiple input variables to output an estimation value of the temperature of the catalyst. The multiple input variables include at least one variable of an ambient temperature variable or an excess amount variable. The multiple input variables further include a fluid energy variable, which is a state variable related to energy of fluid flowing into the catalyst, and a previous cycle value of the estimation value of the temperature of the catalyst. The processing circuitry is configured to execute an acquisition process, a temperature calculation process, and an operation process. The mapping data includes data that is learned through machine learning.

A reduction in measurement accuracy of a concentration sensor is minimized. An exhaust gas purifying device of a work machine includes a reduction catalyst that is placed in an exhaust flow passage of an exhaust gas of an engine and uses a reducing agent to reduce and purify nitrogen oxides in the exhaust gas, and a reducing agent injector to inject the reducing agent into the exhaust flow passage. The exhaust gas purifying device of a work machine includes: a storage unit that stores the reducing agent; a concentration sensor that has a sensing part placed within the storage unit to detect a concentration of the reducing agent; an air-bubble removal device that injects the reducing agent toward the sensing part; and a reducing agent pump that supplies the reducing agent in the storage unit to the air-bubble removal device.

A control apparatus controls an exhaust purification system including an exhaust purification catalyst provided in an exhaust passage for an internal combustion engine in a vehicle, and an electric heating device for heating the exhaust purification catalyst in response to the supply of electricity. The control apparatus includes a prediction unit that detects at least one preliminary action of a startup action for the vehicle performed before the startup operation and predicts that the startup operation will be performed, and a heating control unit that causes the electric heating device to heat the exhaust purification catalyst if the prediction unit predicts that the startup operation will be performed.