Electric dust collecting apparatus

Patent metadata

Field	Value
Publication number	US-11459922-B2
Application number	US-201816195899-A
Country	US
Kind code	B2
Filing date	Nov 20, 2018
Priority date	Jan 18, 2018
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

The electric dust collecting apparatus comprises a plurality of discharge electrodes that are disposed in an exhaust flow passage, a ground electrode that constitutes at least a part of an inner wall surface of the exhaust flow passage, and a voltage applying device that is configured to apply voltage selectively from a common power supply to each of the plurality of discharge electrodes. The plurality of discharge regions, each of which includes at least one discharge electrode, are provided in the exhaust flow passage and an electrode-to-electrode distance between the discharge electrode and the ground electrode is different in each of the plurality of discharge regions. The voltage applying device applies voltage to the discharge electrode for each discharge region, and changes the discharge region where voltage is applied to the discharge electrode in accordance with exhaust gas temperature.

First claim

What is claimed is:

1. An electric dust collecting apparatus that charges and collects particulate matter included in exhaust gas, comprising:
a plurality of discharge electrodes that are disposed in an exhaust flow passage;
a ground electrode that constitutes at least a part of an inner wall surface of the exhaust flow passage; and
a voltage applying device that is configured to apply voltage selectively from a common power supply to each of the plurality of discharge electrodes,
wherein a plurality of discharge regions, each of which includes at least one discharge electrode of the plurality of discharge electrodes, are provided in the exhaust flow passage and an electrode-to-electrode distance between the at least one discharge electrode and the ground electrode is different in each of the plurality of discharge regions; and
wherein the voltage applying device applies voltage to the at least one discharge electrode for each discharge region via a switch, and operates the switch to change a discharge region where voltage is applied to the at least one discharge electrode in accordance with a temperature region to which exhaust gas temperature belongs.

2. The electric dust collecting apparatus according to claim 1 ,
wherein the voltage applying device varies the voltage applied to the at least one discharge electrode included in the discharge region connected to the common power supply via the switch in accordance with the temperature region to which the exhaust gas temperature belongs.

3. The electric dust collecting apparatus according to claim 1 ,
wherein the temperature region where voltage is applied to the at least one discharge electrode is set lower in a discharge region where the electrode-to-electrode distance is shorter than in a discharge region where the electrode-to-electrode distance is longer.

4. The electric dust collecting apparatus according to claim 3 ,
wherein the switch is a selector switch that changes the at least one discharge electrode connected to the common power supply for each discharge region; and
wherein the voltage applying device operates the selector switch to select a discharge region to which voltage is applied in accordance with the temperature region to which the exhaust gas temperature belongs.

5. The electric dust collecting apparatus according to claim 3 ,
wherein the voltage applied to the at least one discharge electrode is set higher in a discharge region where the electrode-to-electrode distance is shorter than in a discharge region where the electrode-to-electrode distance is longer.

6. The electric dust collecting apparatus according to claim 1 ,
wherein an upper limit temperature of the temperature region where voltage is applied to the at least one discharge electrode is set lower in a discharge region where the electrode-to-electrode distance is shorter than in a discharge region where the electrode-to-electrode distance is longer.

7. The electric dust collecting apparatus according to claim 6 ,
wherein the upper limit temperature is set for each discharge region;
wherein the switch is an on-off switch that turns on and off the connection between the common power supply and the at least one discharge electrode for each discharge region;
wherein, when the exhaust gas temperature has reached the upper limit temperature set for a certain discharge region, the voltage applying device operates the on-off switch to turn off the connection between the common power supply and the at least one discharge electrode in the certain discharge region corresponding to the upper limit temperature which the exhaust gas temperature has reached; and
wherein, when the exhaust gas temperature falls below the upper limit temperature set for a certain discharge region, the voltage applying device operates the on-off switch to turn on the connection between the common power supply and the at least one discharge electrode in the certain discharge region corresponding to the upper limit temperature which the exhaust gas temperature has fallen below.

8. The electric dust collecting apparatus according to claim 6 ,
wherein an applicable voltage that is applicable to the at least one discharge electrode is set lower in a discharge region where the electrode-to-electrode distance is shorter than in a discharge region where the electrode-to-electrode distance is longer; and
wherein the voltage applying device sets the applicable voltage set for a discharge region where the electrode-to-electrode distance is shortest among target discharge regions where voltage is applied to the at least one discharge electrode as the applied voltage for all the target discharge regions.

9. The electric dust collecting apparatus according to claim 1 ,
wherein the voltage applying device corrects the voltage applied to the at least one discharge electrode included in the discharge region connected to the common power supply via the switch in accordance with an estimated deposit amount of the particulate matter deposited on the at least one discharge electrode or the ground electrode.

10. The electric dust collecting apparatus according to claim 1 ,
wherein a distance from an axis center of the at least one discharge electrode to the ground electrode is identical among the plurality of discharge regions, a length from the axis center to a tip of the at least one discharge electrode is different in each of the plurality of discharge regions, and thereby the electrode-to-electrode distance is different in each of the plurality of discharge regions.

11. The electric dust collecting apparatus according to claim 1 ,
wherein a distance from an axis center of the at least one discharge electrode to the ground electrode is different in each of the plurality of discharge regions, a length from the axis center to a tip of the at least one discharge electrode is identical among the plurality of discharge regions, and thereby the electrode-to-electrode distance is different in each of the plurality of discharge regions.

12. The electric dust collecting apparatus according to claim 10 ,
wherein the exhaust flow passage is formed in a housing installed in an exhaust pipe of an internal combustion engine,
wherein the plurality of discharge regions are provided in the housing.

13. The electric dust collecting apparatus according to claim 11 ,
wherein the plurality of discharge regions are provided separately at pipe parts of the exhaust pipe, the pipe parts having different diameters from each other.

14. An electric dust collecting apparatus that charges and collects particulate matter included in exhaust gas, comprising;
a plurality of discharge electrodes that are disposed in an exhaust flow passage;
a ground electrode that constitutes at least a part of an inner wall surface of the exhaust flow passage; and
a voltage applying device that is configured to apply voltage to each of the plurality of discharge electrodes;
wherein a plurality of discharge regions, each of which includes at least one discharge electrode of the plurality of discharge electrodes, are provided in the exhaust flow passage and an electrode-to-electrode distance between the at least one discharge electrode and the ground electrode is different in each of the plurality of discharge regions; and
wherein the voltage applying device applies voltage from an individual power supply, that is provided for each of the plurality of discharge regions to the at least one discharge electrode for each discharge region, and operates the individual power supply to change a discharge region where voltage is applied to the at least one discharge electrode in ac

Assignees

• Toyota Motor Co Ltd

Inventors

• Sugimoto Kazuhiro

Classifications

• B03C3/49 Primary

  tubular · CPC title

• F01N3/027

  using electric or magnetic heating means · CPC title

• F01N3/01 Primary

  by means of electric or electrostatic separators · CPC title

• B03C2201/24

  for measuring or calculating of parameters, e.g. efficiency · CPC title

• B03C3/41

  Ionising-electrodes · CPC title