Denso Corporation

Yusuke Majima

Masumi Kinugawa

Shigeto Yahata

Yuuki Tarusawa

Mao Hosoda

A reducing agent supplying device is for a fuel combustion system that includes a NOx purifying device with a reducing catalyst arranged in an exhaust passage to purify NOx contained in exhaust gas of an internal combustion engine. The reducing agent supplying device supplies a reducing agent into the exhaust passage at a position upstream of the reducing catalyst. The reducing agent supplying device includes a reforming portion and a reformation suppressing portion. The reforming portion reforms the reducing agent by partially oxidizing the reducing agent. When a temperature of the reducing agent is higher than a first specified temperature that is equal to or higher than an activation temperature of the reducing catalyst, the reformation suppressing portion (i) suppresses the degree of reformation of the reducing agent in comparison with when a temperature of the reducing agent is lower than the first specified temperature, or (ii) stops the reformation of the reducing agent.

Reducing agent supplying device

A reducing agent supplying device includes a reaction container, an ozone generator, an air pump, an ozone-containing air pipe, a compressed air pipe, a switching device, and a switching controller. The reaction container defines a reaction chamber therein in which a reducing agent is reformed. The ozone generator generates ozone from oxygen in air. The air pump supplies air into the ozone generator. An ozone-containing air flows through the ozone-containing air pipe toward the reaction chamber. A portion of a compressed air flows through the compressed air pipe toward the reaction chamber. The switching device switches between an air pump mode, in which the ozone-containing air is supplied into the reaction chamber, and a supercharging mode, in which the compressed air is supplied into the reaction chamber. The switching controller controls the switching device based on a catalyst temperature, which is a temperature of the reducing catalyst, and an exhaust pressure, which is a pressure in the exhaust passage.

In a condition where an engine is running, a fuel injector injects no fuel, and a fuel pump discharges no fuel so that a fuel pressure in a common-rail is kept constant, an ECU computes an actual torque based on a current engine speed and determines whether the actual torque is increased or decreased relative to a predetermined reference torque. Moreover, in the same condition as above, a fuel pressure in the common-rail is detected. Based on variations of the actual torque and the fuel pressure in the common-rail, the ECU determines whether an abnormality occurs and identifies a type of the abnormality.

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Kariya, Japan

Yusuke Majima