Mazda Motor Corporation

Mazda Motor Corporat Ion

Yoshiaki Tomita

Takayuki Yamaguchi

Daishi Ikeda

Goro Tsuboi

Chikara Ishihara

Masanobu Kanno

Hiroyuki Nishimura

Masayuki Tetsuno

Hiroshi Hayashibara

Hiroaki Gotan

Hiroaki Ishida

Masashi Naono

Masato Katsuta

Kazunori Hirasawa

Kota Matsue

Kaoru Yamada

Tamiharu Nakamura

Takashi Tanaka

An NHsupply amount controller reduces and adjusts a supply amount of NHto an SCR catalyst by an NHsupplier, when an exhaust gas flowing into an NOcatalyst has a rich air-fuel ratio and NOoccluded by the NOcatalyst is reduced to N. A reduction amount of the supply amount of the NHcontrolled by the NHsupply amount controller is set larger when s flow amount of the exhaust gas detected or estimated by an exhaust-gas flow amount detector is larger.

Exhaust gas purification controller for engine

An NHsupply amount controller reduces and adjusts a supply amount of NHto an SCR catalyst by an NHsupplier, when an exhaust gas flowing into an NOcatalyst has a rich air-fuel ratio and NOoccluded by the NOcatalyst is reduced to N. A reduction amount of the supply amount of the NHcontrolled by the NHsupply amount controller is set smaller when a temperature of the NOcatalyst detected or estimated by an NOcatalyst temperature detector is higher.

An NHsupply amount controller reduces and adjusts a supply amount of NHto an SCR catalyst by an NHsupplier, when an exhaust gas flowing into an NOcatalyst has a rich air-fuel ratio and NOoccluded by the NOcatalyst is reduced to N. A reduction amount of the supply amount of the NHcontrolled by the NHsupply amount controller is set larger when an amount of reducing agent detected or estimated by a reducing agent amount detector is larger.

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

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.

Exhaust emission control system of engine

An exhaust emission control system, which comprises control meansoperable, in response to satisfaction of a given stop condition, to automatically stop an engine, and subsequently, in response to satisfaction of a given restart condition, to automatically restart the automatically stopped engine, a flow passageadapted for an aqueous urea solution for reducing nitrogen oxides contained in exhaust gas of the engine, and supply/recovery meansadapted to drive a pumpto supply an aqueous urea solution to the flow passage and recover an aqueous urea solution from the flow passage. The control means is operable, when the engine is forcibly stopped by turning off an ignition switch, to instruct the supply/recovery meansto recover an aqueous urea solution from the flow passage, and, when automatically stopping the engine in response to satisfaction of the given stop condition, to prohibit the supply/recovery meansfrom recovering an aqueous urea solution from the flow passage

Exhaust emission control system for engine and control method therefor

A method is provided for purifying exhaust gas from an engine having an exhaust passage with a selective reducing catalyst and an oxidation catalyst upstream of the selective reducing catalyst. The method calculates an amount of NOx that flows into the selective reducing catalyst; sets an amount of an additive agent to be supplied to the selective reducing catalyst based on the calculated amount of NOx; determines a degradation degree of the oxidation catalyst; determines whether a correction to the amount of the additive agent is necessary based on the determined degradation degree of the oxidation catalyst; corrects the amount of the additive agent to be supplied when the correction is necessary; and supplies the additive agent to the selective reducing catalyst in the corrected amount if the amount is determined to be corrected and in the uncorrected amount if the amount is determined not to be corrected.

Growing community of inventors

Hiroshima, Japan

Yoshiaki Tomita