Isuzu Motors Limited

Masashi Gabe

Daiji Nagaoka

Takehito Imai

Naofumi Ochi

Yoshihisa Tashiro

Tsuneo Suzuki

Hitoshi Sato

Takayuki Sakamoto

Teruo Nakada

Takao Onodera

Hiroyuki Yuza

Takashi Haseyama

Shinji Hara

Takuro Iwashita

Masaaki Nishito

Hidetaka Shibata

Takeshi Igarashi

Takashi Urata

A spray devicesprays a liquid oxidation catalystinto an interior of an upstream small-diameter pipewhich is disposed upstream of an oxidation catalyst, so that the liquid oxidation catalystis supplied to particulate matters which have accumulated on an upstream end faceof the oxidation catalystand a diametrically expanded pipewhich is disposed upstream of the upstream end faceto thereby oxidize and remove the accumulated particulate matters by a catalytic action of the supplied liquid oxidation catalyst, whereby it becomes possible to remove the particulate matters which have accumulated on the upper end faceof the oxidation catalystwhich is disposed in an exhaust passageway and a portion of the exhaust passageway which is situated upstream of the upstream end face

Internal combustion engine and method for removing particulate substance from internal combustion engine

An exhaust gas cleaning system for an internal combustion engine is provided with, in an exhaust passage of an internal combustion engine and in order from an upstream side: a hydrocarbon supply unit; an upstream side catalyst unit of an oxidation catalyst, a NOx reduction catalyst, or the like; and a catalyst-equipped fine particle collection filter having a hydrocarbon adsorption function, wherein when a vehicle on which the engine is mounted accelerates after driving for a preset set time period at a temperature of exhaust gas equal to or less than a preset set exhaust gas temperature, the supply of hydrocarbon into the exhaust gas is started when an exhaust gas temperature becomes equal to or more than a preset first set temperature, and the supply of hydrocarbon is terminated when a preset termination condition is satisfied.

Exhaust gas cleaning system for internal combustion engine and exhaust gas cleaning method for internal combustion engine

An exhaust purification system includes: an NOx reduction type catalyst, which is provided in an exhaust passage; an intake air amount sensor, which detects an intake air amount of the internal combustion engine; and a controller, which executes a regeneration treatment that recovers an NOx purification capacity of the NOx reduction type catalyst by switching an exhaust air fuel ratio from a lean state to a rich state by using: an air-system control to reduce the intake air amount; and an injection-system control to increase a fuel injection amount, wherein, in response to a detection value of the intake air amount sensor, the controller changes at least one of a fuel injection timing and the fuel injection amount in the internal combustion engine, in at least one period of switching of: a period of starting the regeneration treatment; and a period of ending the regeneration treatment.

Exhaust purification system

An engine exhaust gas post-treatment device including a mechanism that can vary opening timing of an exhaust valve, and a control method. A unit is configured to raise a temperature of a part or all of the device to not less than a preset temperature by the mechanism opening the exhaust valve in an exhaust stroke at normal combustion within a range of an afterburning period, and the mechanism feeds the device an exhaust gas whose temperature and pressure are high due to combustion of fuel injected into a cylinder. After the exhaust gas is treated by the device, or when the device is regenerated, the unit adds an unburned fuel component to the exhaust gas by an additional injection of an injector in the cylinder or an injection of a hydrocarbon addition nozzle provided at an exhaust port in accordance with the valve opening timing by the unit.

Internal combustion engine and control method for same

An NOx purification system and a method for control of the NOx purification system. Two oxidation catalysts are provided upstream of an ammonia solution supply unit, and an in-cylinder fuel injection is so controlled that hydrocarbon in exhaust gas is mainly oxidized by an upstream one of the oxidation catalysts and nitric oxide in the exhaust gas is mainly oxidized by a relatively downstream one of the oxidation catalysts. NOx in the exhaust gas is purified by feeding an ammonia solution to a selective reduction NOx catalyst. The system adjusts to the concentrations of HC, NO and NOgoing to the selective reduction NOx catalyst to proper values so as to purify the NOx efficiently by the selective reduction NOx catalyst, and improve NOx purification performance in a lower temperature range.

NOx purification system and method for control of NOx purification system

An NOx purification system having a selective reduction catalyst, adapted so that even when no ammonia or urea is supplied, NOx is converted to ammonia by a first catalyst including a lean NOx catalyst or a ternary catalyst at ammonia formation control and the ammonia is adsorbed by the selective reduction catalyst disposed downstream and so that by the adsorbed ammonia, there is carried out reduction purification of the NOx contained in the exhaust gas when no ammonia formation control is performed by the selective reduction catalyst. At the ammonia formation control, an ammonia adsorption target amount being a target value of ammonia adsorbed by the selective reduction catalyst is computed, and the ammonia formation control is carried out only when a cumulative value of an ammonia formation amount formed by the first catalyst at the ammonia formation control is under the ammonia adsorption target amount. Consequently, ammonia is stably supplied in just proportion to the selective reduction catalyst.

Method of controlling NOx purification system and NOx purification system

An exhaust gas purification system has a NOx purification catalyst that purifies exhaust gas of NOx when an air-fuel ratio of exhaust of an internal combustion engine mounted on a vehicle is in a lean condition and recovers purification ability when the air-fuel ratio is in a rich condition. The system performs recovery control for setting the exhaust gas to a rich air-fuel condition in order to recover the NOx purification ability of the NOx purification catalyst, and at a time of retardation of the vehicle, both a fuel system rich control and an air intake rich control are used in the recovery control. The recovery control can be performed without worsening the drive comfort of the vehicle and with less fuel consumption.

Exhaust gas purification method and exhaust gas purification system

An exhaust gas purification system performing regeneration control in a rich condition by using control of an intake system for reducing the quantity of intake air together with control of a fuel system for increasing fuel injection amount into a cylinder. Timing for injecting fuel into the cylinder is varied in response to a continuous variation of an air fuel ratio in the cylinder during switching intervals between a lean condition and the rich condition at the time of regeneration control of a NOx purification catalyst. During a period of transition to rich condition or lean condition, misfiring, combustion noise, torque variation, deterioration in drivability, and the like, due to undue advance angle or lag angle in the timing for injecting fuel into the cylinder, can thereby be prevented.

Exhaust gas purifying method and purifier

In a NOx purification systemprovided with a NOx occlusion reduction catalystand a control unitwhich executes a NOx regeneration control and a sulfur poisoning regeneration control, a binary &#x3bb; sensorand a reducing agent concentration sensorfor detecting a concentration of the reducing agent are disposed downstream of the NOx occlusion reduction catalyst. The level of deterioration of the NOx occlusion reduction catalystcaused by sulfur poisoning is estimated on the basis of a time period Ta from a time point Tat which a marked decrease of oxygen concentration is detected by the binary &#x3bb; sensorto the time point Tat which the marked increase of the oxygen concentration is detected by the reducing agent concentration sensorunder the NOx regeneration control. Accordingly, the sulfur poisoning amount is accurately estimated and by performing the sulfur poisoning regeneration at an appropriate frequency, any excessive sulfur poisoning regeneration can be avoided, thereby preventing deterioration of mileage.

An exhaust gas purification system provided with an exhaust gas purification device, such as a NOx occlusion-reduction catalyst, in an exhaust passage of an internal combustion engine for purifying exhaust gas when the air-fuel ratio of the exhaust gas is in a lean state, and recovering purification ability when in a rich state. The system prevents highly dense, uncombusted fuel from acting as a binder that causes soot, together with the uncombusted fuel, to clog an EGR cooler in an EGR passage. An uncombusted fuel adsorption device for adsorbing uncombusted fuel is provided upstream of the EGR cooler for adsorbing uncombusted fuel passing through the EGR passage during a rich control.

An NOx purification system having NOx occlusion reduction-type catalysts including an occlusion material and a metal catalyst, which occludes NOx in a lean state in terms of a fuel-air ratio of an exhaust gas and releases the occluded NOx in a rich state. A high-temperature type catalyst is placed on the upstream side, and a low-temperature type catalyst is disposed on the downstream side in series with the high-temperature type catalyst. The molar ratio of platinum to rhodium supported on the high-temperature type catalyst is within a range of 2:1 to 1:2. This NOx purification system is capable of a wide NOx activation temperature window.

Nitrogen oxide purification system

Method of controlling an NOx purification system provided with an NOx occlusion reduction catalyst and a control unit that conducts NOx regeneration control and sulfur poisoning regeneration control. A degree of deterioration of the NOx occlusion reduction catalyst due to sulfur poisoning is estimated on the basis of an amount of an integrated value of a difference between an oxygen concentration on an outlet side of the NOx occlusion reduction catalyst and an oxygen concentration on an inlet side thereof. In so doing, the amount of sulfur poisoning in the NOx occlusion reduction catalyst is accurately estimated, excessive sulfur poisoning regeneration can be avoided, and fuel consumption can be reduced.

An exhaust gas purification system including a reducing agent supplying apparatus and an exhaust gas purification apparatus, in that order from an upstream side of an exhaust passage in an internal combustion engine, and a control unit for controlling an amount of reducing agent supplied into the exhaust gas to recover purification capability of the exhaust gas purification apparatus. A concentration of the reducing agent in the exhaust gas, which flows into the exhaust gas purification apparatus, is varied temporally. The reducing agent is supplied in a proper amount to efficiently recover the purification capability. At the same time, the outflow of the reducing agent to the downstream side of the exhaust gas purification apparatus can be prevented.

Regeneration control method for exhaust gas purification system, and exhaust gas purification system

In regeneration control of an exhaust gas purification system () equipped with NOx occlusion reduction catalyst (), a decision is made whether operating state of an engine is in a first engine operating range where the exhaust gas temperature is lower than a predetermined mode judgment temperature. If yes, EGR rich control is performed. Otherwise, injection rich control in exhaust pipe is performed. When EGR rich control is performed, a decision is made whether a vehicle is under acceleration or not. If a decision is made that the vehicle is under acceleration, regeneration control is postponed until that decision ends. This enables rich control for regeneration the NOx occlusion reduction catalyst (), while avoiding deterioration in drivability (comfortableness) during acceleration of the vehicle.

Exhaust gas purification method and system

Structure for guiding exhaust gas flow to an exhaust gas sensor in exhaust gas purification device installed in an exhaust passage, wherein a plurality of exhaust gas purification units is disposed in series in a container, the exhaust gas sensor is installed between the exhaust gas purification units and guide plates/pipes direct the exhaust gas flowing to the sensor to increase the exhaust gas sensor's responsiveness.

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Fujisawa, Japan

Masashi Gabe