Isuzu Motors Limited

Isuzu Motors Limi Ted

Takayuki Sakamoto

Daiji Nagaoka

Teruo Nakada

Hiroyuki Yuza

Masaaki Nishito

Masashi Gabe

Tomohiro Korenaga

The present invention is provided with: a SOx purge control unit that executes catalyst regeneration processing that maintains the temperature of a NOx occlusion/reduction catalyst at a prescribed recovery temperature; a catalyst temperature estimation unit that estimates catalyst temperature on the basis of the amount of unburnt fuel contained in exhaust and of a catalyst heat generation amount; a second exhaust temperature sensor that is arranged further to an exhaust downstream side than the catalyst and that detects exhaust temperature; and a heat generation amount correction value setting unit that, during the execution of the catalyst regeneration processing, on the basis of an estimated catalyst temperature estimated by the catalyst temperature estimation unit and of an actual exhaust temperature detected by the second exhaust temperature sensor, obtains a heat generation amount correction value that is used to correct the heat generation amount of the catalyst.

Exhaust purification device and control method for same

A control apparatus (): creates a torque correction table indicating a relationship between a change rate of an intake air amount, a change of the main injection amount and the main injection timing of a fuel injection apparatus () in the torque value of a diesel engine () in a lean state; measures an intake air amount in a rich state by using an MAF sensor (); calculates a change rate of the measured intake air amount for the intake air amount in the lean state; obtains a correction value of the main injection amount and a correction value of the main injection timing of the fuel injection apparatus () based on the calculated change rate and the torque correction table; and performs an injection of the fuel in the rich state at the main injection amount and the main injection timing, corrected by the respective correction values.

Exhaust gas purifying system

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.

Exhaust gas purification system for internal combustion engine, internal combustion engine, and exhaust gas purification method for internal combustion engine

An exhaust purification system includes: an NOx reduction type catalyst; an MAF sensor; an SOx purge control unit that uses an air system control having an intake air amount feedback-controlled based on a target intake air amount and an injection system control for a target injection increase amount set based on the target intake air amount, and a fuel injection amount feedback-controlled based on the target injection increase amount; an SOx purge prohibition processing unit that prohibits an SOx purge control; and a warming mode control unit that open-loop controls an air system when the SOx purge control is prohibited, controls the fuel injection amount, and maintains the exhaust gas at a temperature. The SOx purge control unit executes the injection system control by switching the target intake air amount into an actual intake air amount when starting the SOx purge control after a warming mode control is ended.

Exhaust purification system and catalyst regeneration method

An exhaust purification system includes a NOx-occlusion-reduction-type catalyst that occludes NOx in exhaust in a lean state and reduces and purifies the occluded NOx in exhaust in a rich state, and a NOx purge rich control unit that executes NOx purge of reducing and purifying the occluded NOx by putting the exhaust into the rich state by fuel injection control, where a catalyst temperature of the NOx-occlusion-reduction-type catalyst is equal to or higher than a catalyst temperature threshold value and a NOx occlusion amount of the NOx-occlusion-reduction-type catalyst is equal to or higher than an NOx occlusion amount threshold value, and executes the NOx purge when the catalyst temperature is lower than a catalyst temperature threshold value.

NOx occlusion amount estimating device and NOx occlusion amount estimating method

An exhaust purification system including a NOx catalystprovided in an exhaust passage of an internal combustion engineand purifying NOx in exhaust; a MAF sensorfor acquiring an air flow-rate of the internal-combustion engine; a control unitthat execute catalyst regeneration treatment of recovering a NOx purification ability of the NOx catalystby performing, in combination, air-based control of reducing air flow-rate of the internal-combustion engineto a predetermined target air flow-rate and injection-based control of increasing a fuel injection amount, wherein, in a case of executing the catalyst regeneration treatment, the control unitstarts with the air-based control and starts the injection-based control when the air flow-rate acquired by the MAF sensoris reduced to the target air flow-rate.

Exhaust purification system

Provided is an exhaust purification system including: an NOx occlusion reduction type catalyst that is provided in an exhaust system of an internal combustion engine, and occludes NOx when an exhaust gas is in a lean state, and reduces the NOx when the exhaust gas is in a rich state; a regeneration control unit that executes a regeneration process of bringing the exhaust gas into a rich state to reduce the NOx occluded in the NOx occlusion reduction type catalyst; a storing unit that stores an exhaust lambda prediction value in advance when the regeneration process is executed; a reduction amount estimating unit that estimates an NOx reduction amount when the regeneration process is executed; and a prohibition unit that prohibits the execution of the regeneration process by the regeneration control unit when the estimated NOx reduction amount is less than a predetermined lower limit threshold.

An internal combustion engine control device including an oxidation catalyst heating value estimation unitA, a NOx catalyst heating value estimation unitB, an oxidation catalyst temperature estimation unitC, a NOx catalyst temperature estimation unitD, and switchesthat switch between an enabled state in which processing performed by the oxidation catalyst heating value estimation unitA and the oxidation catalyst temperature estimation unitC is executed and a disabled state in which the processing performed by the oxidation catalyst heating value estimation unitA and the oxidation catalyst temperature estimation unitC is not executed, wherein the control device is configured to be applied to both an exhaust gas purification system including an NOx-occlusion-reduction-type catalyst and an oxidation catalyst and an exhaust gas purification system including the NOx-occlusion-reduction-type catalyst and not including the oxidation catalyst.

Internal combustion engine control device

An exhaust purification system is provided with a NOx-occlusion-reduction-type catalyst and a NOx purge rich control unit that executes NOx purge of reducing and purifying the occluded NOx by putting the exhaust into a rich state by fuel injection control, in a case where a catalyst temperature of the NOx-occlusion-reduction-type catalyst is equal to or higher than a catalyst temperature threshold value and a NOx occlusion amount of the NOx-occlusion-reduction-type catalyst is equal to or higher than an NOx occlusion amount threshold value, and executes the NOx purge even when the NOx occlusion amount is less than the NOx occlusion amount threshold value, in a case where the catalyst temperature is equal to or higher than a catalyst temperature threshold value which is greater than the catalyst temperature threshold value.

There is provided: a NOx occlusion reduction-type catalyst that is provided in an exhaust passage of an internal combustion engine, occludes NOx in exhaust when the exhaust is in a lean state, and reduces and purifies the occluded NOx when the exhaust is in a rich state; an exhaust injector that is provided in the exhaust passage and is positioned further upstream than the NOx occlusion reduction-type catalyst; a NOx-purging control unit that performs NOx purging of reducing and purifying the NOx occluded in the NOx occlusion reduction-type catalyst by lowering the exhaust to a prescribed target lambda by fuel injection by the exhaust injector; and a NOx-purging-prohibition processing unit that inhibits performance of the NOx purging in a case where the exhaust cannot be lowered to the target lambda even if the fuel injection is performed at a maximum limit injection amount of the exhaust injector.

An exhaust purification system is provided with a NOx-occlusion-reduction-type catalystthat occludes NOx in exhaust when the exhaust is in a lean state and reduces and purifies the occluded NOx when the exhaust is in a rich state, and a NOx purge rich control unitfor reducing and purifying NOx occluded in the NOx-occlusion-reduction-type catalystby putting the exhaust into the rich state by repetitively performing fuel injection control of at least one of post injection and exhaust pipe injection at a predetermined interval.

There is provided: a NOx-occlusion-reduction-type catalystthat is provided in an exhaust passageof an internal combustion engine; a NOx purge control unitthat performs a NOx purge control of setting the exhaust in the rich state and reducing and purifying NOx occluded in the NOx-occlusion-reduction-type catalyst; and a NOx purge inhibition processing unitthat inhibits NOx purge control when the internal combustion enginebecomes a motoring state in which fuel injection is stopped, and inhibiting, when the internal combustion enginehas started fuel injection during the inhibition of the NOx purge control, performance of the NOx purge control from the start of the fuel injection until a predetermined period of time has elapsed.

An exhaust purification system includes an exhaust after-treatment apparatus which is provided on an exhaust passage of an internal combustion engine and which includes catalysts for purifying exhaust gas, a catalyst temperature retention control module for executing a catalyst temperature retention control in which an intake air flow is reduced to thereby suppress a reduction in the temperature of the catalysts when the internal combustion engine is in a motoring state where fuel injection into the internal combustion engine is stopped, and a prohibition module for prohibiting the execution of the catalyst temperature retention control in a case where an activation of an exhaust brake system is detected while the internal combustion engine is in the motoring state.

Exhaust purification system and control method therefor

An exhaust purification system includes: an NOx reduction type catalyst, which is provided in an exhaust system; a temperature acquisition unit, which acquires a catalyst temperature of the NOx reduction type catalyst; and a regeneration treatment unit, which executes a catalyst regeneration to recover an NOx purification capacity, wherein the regeneration treatment unit alternately executes a rich control, in which an exhaust air fuel ratio is set to a rich state to raise a temperature of the NOx reduction type catalyst to a predetermined target temperature, and a lean control, in which the exhaust air fuel ratio is set to a lean state to lower the temperature of the NOx reduction type catalyst, and sets an execution period of the lean control based on a deviation between the catalyst temperature acquired by the temperature acquisition unit during the previous rich control and the target temperature.

The embodiments include: a NOx occlusion/reduction catalyst which is provided to an exhaust passage of an internal combustion engine, occludes NOx in exhaust when the exhaust is in a lean state, and reduces and purifies occluded NOx when the exhaust is in a rich state; a NOx purging control unit which, when the exhaust is in the rich state, executes NOx purging in which the NOx occluded in the NOx occlusion/reduction catalyst is reduced and purified; and a NOx-purging-prohibition processing unit which, when at least one of a plurality of prohibition conditions is fulfilled, prohibits execution of catalyst regeneration processing by the NOx purging control unit even if a catalyst-regeneration-processing start request has been issued, and, when one of the prohibition conditions is fulfilled during execution of the catalyst regeneration processing, invalidates the prohibition condition and allows continued execution of the catalyst regeneration processing by the NOx purging control unit.

Growing community of inventors

Fujisawa, Japan

Takayuki Sakamoto