Exhaust gas cleaning device for diesel engine

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be explained in accordance with the several embodiments with reference to the drawings.
In FIGS.
1-3, an exhaust gas cleaning device A is connected to an exhaust pipe 2 of a diesel engine 1.
The exhaust gas cleaning device A is provided with a metallic casing 3 having an inlet port 3a communicated with the exhaust pipe 2 and an outlet port 3b, a filter member 4 which is accomodated within the metallic casing 3 for collecting the carbon particulates and a heater wire 5a of an electric heater 5 which is buried within the end portion of the filter member 4 on the upstream side of the latter.
To the metallic casing 3, a differential pressure sensor 8 is mounted for detecting the differential pressure between the upstream side and the downstream side of the filter member 4.
The sensor 8 is connected to a relay 10 through a control circuit 7.
The heater wire 5a is buried within the exhaust gas inlet end portion of the filter member 4 and is connected to a battery 6 through the relay 10.
As the exhaust gases containing combustible particulates pass the filter member 4, the particulates are collected by the filter member 4.
As the amount of the collected particulates increases, the flowing resistance of the filter member 4 gradually rises.
As a result, the differential pressure between the inlet side and the outlet side of the filter member 4 increases.
When the differential pressure sensor 8 detects when the differential pressure reaches a predetermined pressure, the control circuit 7 generates an electric signal and the relay 10 changes into ON state.
Then, electric current flows into the heater wire 5a from the battery 6.
The heater wire 5a applies heat to the particulates collected in the end portion 42 of the filter member 4 and the particulates begin to burn.
The heat generated due to the combustion of the particulates in the end portion 42 is transmitted toward the outlet side of the filter member 4 by the exhaust gas flow