Mazda Motor Corporation

Masanobu Kanno

Masayuki Tetsuno

Takayuki Yamaguchi

Hiroyuki Nishimura

Kenji Tanimura

Eiji Nakai

Motoshi Kataoka

Kota Maekawa

Yoshiaki Tomita

Daishi Ikeda

Hiroshi Hayashibara

Koichi Sugimoto

Kazunori Hirasawa

Kota Matsue

Kaoru Yamada

Kenta Ando

Takashi Tanaka

Tomohiro Taketani

An exhaust emission control device for an engine is provided with a first purifying catalyst including an HC adsorbent that adsorbs HC at a low temperature and releases HC at a high temperature and a diesel oxidation catalyst capable of oxidizing HC, a second purifying catalyst including a NOx catalyst capable of storing NOx contained in exhaust, a NOx catalyst regenerator that regenerates the NOx catalyst while raising the temperature of the NOx catalyst, and HC controller that decides whether the amount of adsorbed HC that is HC adsorbed by the HC adsorbent is equal to or more than a preset reference amount and, when the amount of adsorbed HC is decided to be equal to or more than the reference amount, raises the temperature of the first purifying catalyst.

Exhaust emission control device, method and computer program product for an engine

A control system for an engine is provided, which includes an engine body formed with a cylinder, a NOcatalyst, an oxidation catalyst, a PM filter, a fuel injector configured to perform a main injection and a post injection, and a controller configured to execute a DeNOcontrol in which the fuel injector is controlled to perform the main and post injections so that an air-fuel ratio of exhaust gas is brought close to the stoichiometric air-fuel ratio or becomes rich and fuel supplied into the cylinder by the post injection combusts therein, and a filter regenerating control in which the fuel injector is controlled to perform the main and post injections so that the air-fuel ratio becomes lean and the fuel supplied into the cylinder by the post injection causes no combustion therein, the controller executing the DeNOcontrol and the filter regenerating control consecutively in this order.

Control system for engine

A NOcatalyst is provided on an exhaust passage of an engine. The NOcatalyst reduces the occluded NOwhen an air-fuel ratio of exhaust gas is in the vicinity of a stoichiometric air-fuel ratio or in a richer state than the stoichiometric air-fuel ratio. Turbocharging is executed by turbochargers. In a low load region within the reduction execution region, a target air-fuel ratio is achieved, as required for NOreduction, by air amount adjustment with an air amount control valve provided on an intake passage. Since a large amount of air is needed in the high load region within the reduction execution region, the target air-fuel ratio is achieved by air amount adjustment using turbocharging pressure control.

Exhaust purification device of engine

An exhaust emission control system is provided, which includes a NOstorage catalyst provided in an exhaust passage of an engine and configured to store NO, a urea SCR catalyst provided in the exhaust passage, downstream of the NOstorage catalyst, and a NOreduction controlling module configured to set a NOreduction condition and, when the NOreduction condition is satisfied, performs NOreduction processing in which an air-fuel ratio of exhaust gas is set to be one of near a stoichiometric air-fuel ratio and rich, and the NOstored in the NOstorage catalyst is reduced, the NOreduction condition being set looser for the NOreduction processing performed the first time after the engine is started than the NOreduction processing performed the second and subsequent times after the engine is started.

Exhaust emission control system

An exhaust emission control system of an engine including a NOcatalyst disposed in an exhaust passage and for storing NOwithin exhaust gas when an air-fuel ratio of the exhaust gas is lean, and reducing the stored NOwhen the air-fuel ratio is approximately stoichiometric or rich, is provided. The system includes a SCR catalyst disposed downstream of the NOcatalyst and for purifying NOby causing a reaction with ammonia, and a processor configured to execute a NOreduction controlling module for controlling the air-fuel ratio to a target ratio so that the stored NOis reduced. The controlling module limits the performance of the NOreduction control when a temperature of the SCR catalyst is above a given temperature and loosens the limitation in a given engine operating state in which an exhaust gas flow rate is above a given rate despite the SCR catalyst temperature.

Exhaust emission control system of engine

An exhaust emission control system of an engine, including an NOcatalyst disposed in an exhaust passage for storing NOwithin exhaust gas when an air-fuel ratio of the exhaust gas is lean, and reducing the stored NOwhen the air-fuel ratio is approximately stoichiometric or rich, is provided. The system includes an SCR catalyst disposed in the exhaust passage downstream of the NOcatalyst and for purifying NOwithin exhaust gas by causing a reaction with ammonia, a controller executing a NOreduction controlling module for executing a control in which the air-fuel ratio is controlled to a target air-fuel ratio so that the stored NOis reduced, and an ammonia adsorption amount acquiring module for acquiring an ammonia adsorption amount of the SCR catalyst by detection or estimation. The NOreduction controlling module controls the target air-fuel ratio to be leaner as the ammonia adsorption amount increases.

An exhaust emission control system of an engine including a NOcatalyst for storing NOwithin exhaust gas when an air-fuel ratio thereof is lean, and reducing the NOwhen the air-fuel ratio is approximately stoichiometric or rich, the NOcatalyst also functioning as an oxidation catalyst for oxidizing HC, is provided. The system includes a SCR catalyst for purifying NOby causing a reaction with NH, a urea injector, and a processor configured to execute a fuel injection controlling module, and a NOreduction controlling module for performing a NOreduction control to enrich the air-fuel ratio to a target ratio. When the urea injection is abnormal, the NOreduction controlling module performs an NH-supplied NOreduction control in which the NOcatalyst supplies NHto the SCR catalyst, by performing the NOreduction control, a lean air-fuel ratio operation control, and then the NOreduction control again.

An exhaust emission control system of an engine is provided including a NOcatalyst for oxidizing HC and storing NOwithin exhaust gas when an air-fuel ratio of the exhaust gas is lean, and reducing the NOwhen the air-fuel ratio is approximately stoichiometric or rich. The system includes a SCR catalyst for purifying NOby causing a reaction with NH, a urea injector, a fuel injection controlling module, and a processor configured to execute a NOreduction controlling module for performing a NOreduction control to enrich the air-fuel ratio to reach a target ratio. When the urea injection is determined to be abnormal, the NOreduction controlling module performs a NH-supplied NOreduction control in a state where a larger amount of unburned fuel than the amount of unburned fuel in the exhaust passage in the NOreduction control is supplied to the exhaust passage.

An exhaust emission control system of an engine is provided, which includes a NOcatalyst disposed in an exhaust passage for storing NOwithin exhaust gas when an air-fuel ratio of the exhaust gas is lean, and reducing the stored NOwhen the air-fuel ratio is approximately stoichiometric or rich. A processor executes a NOreduction controlling module for performing, when the NOstored amount exceeds a given amount, a NOreduction control in which a fuel injector performs a post injection of fuel to continuously control the air-fuel ratio to a target ratio so that the stored NOis reduced to be below a given amount, the target air-fuel ratio being a ratio at which the stored NOis reducible, the post injection causing the injected fuel to combust inside a cylinder, the execution of the control permitted when an engine load is within a medium load range.

An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; a low-pressure EGR passage connecting a part of the exhaust passage downstream of the turbine to a part of the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area of the low-pressure EGR passage; an exhaust shutter valve disposed downstream of the connected part of the exhaust passage to the low-pressure EGR passage, and for changing a cross-sectional area of the exhaust passage; a valve control device for controlling openings of the low-pressure EGR valve and the exhaust shutter valve; and a gear range detector for detecting a gear range of a transmission of a vehicle in which the engine is installed.

Exhaust gas recirculation control system of engine

An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; an intercooler disposed in the intake passage downstream of the compressor; a low-pressure EGR passage connecting the exhaust passage downstream of the turbine to the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area thereof; a high-pressure EGR passage connecting the exhaust passage upstream of the turbine to the intake passage downstream of the intercooler; a high-pressure EGR valve disposed in the high-pressure EGR passage and for changing a cross-sectional area thereof; a valve control device for controlling openings of the low-pressure and high-pressure EGR valves; and a gear range detector for detecting a gear range of a transmission.

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Hiroshima, Japan

Masanobu Kanno