Shin Caterpillar Mitsubishi Ltd.

Nippon Donaldson Ltd.

Masayoshi Kajitani

Izuru Morita

Shoji Tozawa

Kisaburo Otabe

Keisuke Kishitani

Masao Kodama

Masanori Satoh

Mamoru Onda

Masanobu Takano

A method of and apparatus for reducing smoke emitted from a diesel engine are disclosed. The apparatus comprises: a trap for trapping black smoke particles which is disposed within the exhaust system of the engine, the trap including a ceramic trap assembly having a honeycomb structure in which a catalyst which enables lowering of the combustion temperature of black smoke is carried on internal passage walls; a pressure sensor provided at the inlet of the trap; an engine speed sensor; a butterfly valve provided in the intake system of the engine; and a combination of a controller and an actuator for the butterfly valve. In this apparatus and method the controller obtains a specified exhaust pressure range in the trap on the basis of a signal from the engine speed sensor, compares an exhaust pressure signal from the pressure sensor with the specified exhaust pressure range, and controls the actuator so that the actuator controls the degree of opening of the butterfly valve so that the exhaust pressure inside the trap is maintained within the specified exhaust pressure range. By this means, black smoke particles can be controllably burned by means of exhaust gas without causing any engine trouble. Since the trap can be regenerated with the ceramic trap assembly left in place in, for example, a construction machine, it is possible to provide a diesel engine smoke reducing apparatus which is superior in both serviceability and durability.

Method of and apparatus for reducing engine smoke emissions

An apparatus which is disposed in an exhaust system of a diesel engine for treating particulate emissions contained in exhaust gas is disclosed. The apparatus comprises a splittable casing body including an inlet-side casing portion and an outlet-side casing portion, an inlet pipe secured to the inlet-side casing portion, an outlet pipe secured to the outlet-side casing portion, a partition plate detachably retained between the inlet- and outlet-side casing portions such as to divide the inside of the casing body into two compartments, and at least one filter assembly detachably mounted in an opening provided in the partition plate. The filter assembly is defined by a honeycomb-type ceramic filter which is accommodated in a metallic casing and surrounding by a cushioning material, and which has a catalyst carried on its internal passage wall. The catalyst enables a lowering in the combustion temperature of the particulate emissions. The ceramic filter is detachable from the partition plate together with the metallic casing in one unit. Accordingly, it is possible to replace the filter with ease and to vary appropriately the number of filters in accordance with the displacement volume of the engine concerned.

Apparatus for treating particulate emission from diesel engine

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Kanagawa, Japan

Masayoshi Kajitani