Mazda Motor Corporat Ion

Mazda Motor Corporation

Goro Tsuboi

Daishi Ikeda

Takayuki Yamaguchi

Yoshiaki Tomita

Chikara Ishihara

Hiroshi Yamada

Hiroyuki Nishimura

Hiroshi Hayashibara

Yoshiyuki Sato

Yoshio Mizuta

Kazuma Uchiyama

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.

An engine control device is provided, which includes an oxidation catalyst provided in an exhaust passage to oxidize unburned fuel within exhaust gas, a NOcatalyst provided integrally with or downstream of the oxidation catalyst, a PM filter provided in the exhaust passage downstream of the oxidation catalyst to capture fine particulate matter within the exhaust gas, a fuel injector, and a controller. When the particulate matter is accumulated by a given amount, the controller starts a PM filter regeneration control to remove the particulate matter, and after this control is started and when the accumulation amount decreases by a given amount, the controller starts a NOcatalyst regeneration control to switch between a first state in which an air-fuel ratio of the exhaust gas is a stoichiometric air-fuel ratio or less and a second state in which the air-fuel ratio is higher than the stoichiometric air-fuel ratio.

Control device for engine

An engine includes: an NOx catalyst and an SCR catalyst in an exhaust passage; an excess air ratio change device that changes an excess air ratio of an exhaust gas; and a reducing agent supply device that supplies a reducing agent for SCR including a material for NHor NHto a portion between the NOx catalyst and the SCR catalyst in the exhaust passages. The engine controls the reducing agent supply device in such a manner that a quantity of the reducing agent for SCR to be supplied from the reducing agent supply device to the exhaust passagebecomes small when the excess air ratio of the exhaust gas during regeneration control to regenerate the NOx catalyst is small, as compared to when the excess air ratio &#x3bb; of the exhaust gas during regeneration control to regenerate the NOx catalyst is large.

Growing community of inventors

Hiroshima, Japan

Goro Tsuboi