| 主权项 |
1. An exhaust gas treatment device of a diesel engine having an exhaust gas separator (2) disposed on an exhaust gas flow passage (1) to allow particulate material (PM) in exhaust gas (3) to be localizedly positioned and thus to separate the exhaust gas (3) into EGR gas (4) containing the localizedly positioned PM and emission gas (5) as the rest of the exhaust gas (3), thereby recirculating the EGR gas (4) to a combustion chamber (42) and emitting the emission gas (5) to the air, the exhaust gas treatment device comprising:
a central cylinder (7) disposed at the center of the exhaust gas separator (2), having an emission gas entry opening, an outlet (30) having a peripheral wall (37), and a plurality of discharge protrusions (6) protruding from an outer periphery of the central cylinder (7); an exhaust gas swirl chamber (9), having a peripheral wall (14), surrounding the central cylinder (7), so that the plurality of discharge protrusions (6) protrude toward the peripheral wall (14) of the exhaust gas swirl chamber (9); an exhaust gas deflection guide wall (18) adjacent the discharge protrusions (6); an exhaust gas swirl approach passage (26), having a peripheral wall (33), along a spirally formed approach guide wall (26a) on an upstream side of the exhaust gas swirl chamber (9); and an emission gas-emitting passage (27), having a peripheral wall (27a) divided into a peripheral wall (35) of an inlet (28) thereof and a peripheral wall (36) downstream from the peripheral wall (35), the peripheral wall (35) of the inlet (28) being interposed between the downstream side peripheral wall (36) of the emission gas-emitting passage (27) and the peripheral wall (37) of the outlet (30) of the central cylinder (7), the peripheral wall (35) of the inlet (28) of the emission gas-emitting passage (27) being formed of the exhaust gas deflection guide wall (18), such that exhaust gas (3) moving toward the discharge protrusions (6) is deflected by the deflection guide wall (18) to the peripheral wall (14) of the exhaust gas swirl chamber (9) around the discharge protrusions (6), the peripheral wall (35) of the inlet (28) being molded of an electrical insulator to electrically insulate the peripheral wall (14) of the exhaust gas swirl chamber (9), the peripheral wall (33) of the exhaust gas swirl approach passage (26) and the downstream side peripheral wall (36) of the emission gas-emitting passage (27), wherein: the exhaust gas separator (2) has electrodes (12, 13) having different polarities from each other to allow the PM in the exhaust gas (3) to be charged to a given polarity by means of corona discharge between the electrodes (12, 13); the central cylinder (7) has electrodes (12) having the same polarity as the charged PM; and the peripheral wall (14) of the exhaust gas swirl chamber (9), the peripheral wall (33) of the exhaust gas swirl approach passage (26) and the downstream side peripheral wall (36) of the emission gas-emitting passage (27) electrodes (13) having an opposite polarity from electrodes (12) of the central cylinder (7) and the charged PM, so that the charged PM in the exhaust gas (3) swirling the exhaust gas swirl chamber (9) is localizedly positioned around the peripheral wall (14) of the exhaust gas swirl chamber (9) through a centrifugal force and an electrostatic force to allow the exhaust gas (3) containing the localizedly positioned PM to be separated as the EGR gas (4) and sent to a terminal end portion (15) of the exhaust gas swirl chamber (9), while the exhaust gas (3) around the central cylinder (7) is being separated as the emission gas (5) and sent to the interior of the central cylinder (7) through the emission gas entry opening. |
