Isuzu Motors Limited

Hiroyuki Yuza

Daiji Nagaoka

Teruo Nakada

Takayuki Sakamoto

Akihide Oogushi

Masashi Gabe

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.

Exhaust purification system and catalyst regeneration method

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 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

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.

Exhaust purification system, and control method for exhaust purification system

An exhaust purification system includes; a catalyst provided in an exhaust passage of an engine to purify an exhaust gas; a catalyst temperature estimating unit that estimates a temperature of the catalyst based on an initial temperature of the catalyst at the time of starting of the engine and a caloric value of the catalyst which changes depending on an operating state of the internal combustion engine; and an initial catalyst temperature setting unit that sets an initial temperature of the catalyst based on a catalyst temperature stored immediately before stopping the engine, a temperature of an exhaust gas flowing into the catalyst which is stored immediately before stopping the engine, a temperature of an exhaust gas flowing into the catalyst which is acquired at the time of starting the engine, and a temperature of air taken into the engine which is acquired at the time of starting the engine.

Exhaust purification system and catalyst control method

When a catalyst temperature of a catalyst device is at or below a lower limit air-fuel ratio richness control is prohibited. When a first timing, where an estimated value of a NOx storage amount has reached an enrichment start threshold value, and a second timing, based on a set interval time in an enrichment interval time map, are both satisfied, the control is started. The second timing is corrected by multiplying the set interval time by an enrichment interval correction coefficient preset based on the catalyst temperature and a storage ratio of the estimated value of the NOx storage amount to an enrichment start threshold value of the NOx storage amount. The frequency of the air-fuel ratio richness control of a catalyst device configured to recover a purification capacity of a catalyst is reduced, and the catalyst temperature is raised while preventing white smoke development and hydrocarbon slip, to thereby achieve improvement in exhaust gas composition and improvement in fuel efficiency.

Exhaust gas purification system and exhaust gas purification method

A diesel oxidation catalyst, a NOx occlusion reduction catalyst, and a diesel particulate filter are connected to an exhaust pipe of an engine, downstream of an exhaust pipe injector provided on the exhaust pipe. NOx in the exhaust gas is occluded by the NOx occlusion reduction catalyst when an air-fuel ratio is lean. The occluded NOx is reduced and purified when the air-fuel ratio is rich. When a prescribed amount of particulate matter has accumulated in the diesel particulate filter, the exhaust gas temperature is raised when performing particulate matter regeneration. The exhaust gas temperature is further raised to perform a sulphur purge. The rich condition is prohibited during the particulate matter regeneration period and the sulphur purge period. When the sulphur purge is completed, the rich condition prohibition continues until the difference between the inlet temperature of the diesel oxidation catalyst and the outlet temperature of the NOx occlusion reduction catalyst becomes equal to or less than a predetermined threshold.

Control method for exhaust gas aftertreatment device

An exhaust gas purification method of a diesel engine, which purifies exhaust gas while suppressing deterioration in drivability and fuel consumption, including when exhaust gas enters a rich reduction state, opening an EGR valve and closing an intake throttle, if a temperature of an NOx occlusion reduction catalyst is at or above a predetermined temperature, and a vehicle having a diesel engine is decelerating from a speed at or above a predetermined speed, and then closing an exhaust throttle provided downstream of the NOx occlusion reduction catalyst and supplying fuel to the NOx occlusion reduction catalyst as a reductant.

Diesel engine exhaust gas purification method and exhaust gas purification system

An exhaust gas purification deviceincludes an exhaust gas processing deviceprovided in an exhaust passageof an internal combustion engine, an in-exhaust pipe fuel injection deviceprovided on an upstream side of the exhaust gas processing deviceto supply fuel to the exhaust gas processing device, a NOx sensorprovided on a downstream side of the exhaust gas processing device, and a control unitthat controls combustion in the internal combustion enginebased on operating state of the engine. To burn and remove PM trapped in the exhaust gas processing device, the control unitcauses the in-exhaust pipe fuel injection deviceto supply the fuel to the exhaust gas processing deviceand stores a detection value from the NOx sensoras a NOx value at an outlet of the engine

Exhaust gas purification device and control method for exhaust gas purification device

A diesel particulate filter ('DPF') system is provided with temperature sensors at an entrance side and an exit side of a diesel oxidation catalyst, an SV ratio determining device that determines an exhaust gas SV ratio by measuring flow rate of exhaust gas during the DPF forcible regeneration, and an injector diagnosing device including a heat-generation region determining unit to which detection values of the temperature sensors and a determination value of the SV ratio determining device are input to determine whether or not these values are within a theoretical heat-generation region, and an actual injection amount diagnosing unit that diagnoses a decrease amount in an actual injection amount of an exhaust pipe injector, when the detection values of the temperature sensors and the determination value of the SV ratio determining device are within the theoretical heat-generation region.

Diesel particulate filter system

An exhaust gas purification method, and system. In order from an upstream side of an engine exhaust passage there are provided, a NOx occlusion-reduction catalyst, a hydrocarbon ('HC') adsorbing member, and a catalyzed diesel particulate filter or oxidation catalyst. During NOx regeneration control, an air-fuel ratio of exhaust gas in terms of excess air factor is taken to be 0.8 to 1.1 when an index temperature representative of the HC-adsorbing member is a first judgment temperature or less, is taken to be 1.0 to 1.1 when the index temperature is between a first judgment temperature and a second judgment temperature, and is taken to be 0.8 to 1.1 when the index temperature is the second judgment temperature or above, causing an outflow of HC to the atmosphere to be reduced.

Exhaust gas purification method and exhaust gas purification system

Provided is a fuel injection control device that affords a wider lower limit range of injection amount by a injector for cylinder outside injection, and that can respond to injection requirements over a wider injection amount range. A fuel injection control device includes: a injectorfor cylinder outside injection that injects fuel into an exhaust passageof an engine, in an amount corresponding to a duty ratio; and a control meansfor controlling the injectorfor cylinder outside injection, wherein the control meanschanges an injector driving frequency upon determining the duty ratio, such that the frequency is lowered, stepwise or continuously, as the required injection amount decreases.

Fuel injection control device

An exhaust gas purifier including an NOx catalyst of the selective reduction type and a diesel particulate filter arranged in series, and being disposed in an exhaust passage of an internal combustion engine. The purifier includes a passage for urea supply having a hydrolysis catalyst therein and a passage for hydrocarbon supply having an oxidation catalyst therein. The passages are parallel to each other and separate on an upstream side of both the NOx catalyst and the diesel particulate filter. A urea feeder which supplies urea to the passage for urea supply and a hydrocarbon feeder supplies hydrocarbon to the passage for hydrocarbon supply. The injection of an urea is thereby reconciled with the direction injection of hydrocarbon into the exhaust pipe in a compact space.

Exhaust gas purifier and system for exhaust gas purification

An exhaust gas purification apparatus including a first exhaust gas treatment member carrying an oxidation catalyst, a three-way catalyst, or a NOx storage reduction catalyst which is used for purifying exhaust gas from an internal combustion engine, a second exhaust gas treatment member having a hydrocarbon ('HC') storing function disposed on the downstream side of the first exhaust gas treatment member, and a heat dissipating unit disposed between the first exhaust gas treatment member and the second exhaust gas treatment member. An upstream side of the heat dissipating unit is formed into a heat insulating structure, and a further upstream side thereof is formed into a heat retaining structure. Even when an internal combustion engine is accelerating, the exhaust gas flowing into the HC adsorption material can be cooled efficiently and HC can be adsorbed before the temperature of the three-way catalyst or the NOx purification catalyst rises to an HC light-off temperature.

Growing community of inventors

Yokohama, Japan

Hiroyuki Yuza