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Emission gas cleaning device of internal combustion engine

Inactive Publication Date: 2014-12-25
DENSO CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent text describes a way to change the output of a gas sensor by controlling the current flow between electrodes. This allows for a change in output without needing to add extra components to the gas sensor, reducing design changes and cost. Additionally, this method can be used in systems with a three-way catalyst, which helps reduce exhaust emissions.

Problems solved by technology

In this case, the emission gas sensor does not need to have the auxiliary electrochemical cell or the like built therein, so that the output characteristic of the emission gas sensor can be changed without causing a significant design change and a large increase in cost of the emission gas sensor.

Method used

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  • Emission gas cleaning device of internal combustion engine
  • Emission gas cleaning device of internal combustion engine
  • Emission gas cleaning device of internal combustion engine

Examples

Experimental program
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embodiment 1

[0045]An embodiment 1 of the present disclosure will be described on the basis of FIG. 1 to FIG. 10.

[0046]First, a general configuration of an entire engine control system will be described on the basis of FIG. 1.

[0047]An intake pipe 12 of an engine 11 is provided with a throttle valve 13, the opening of which is controlled by a motor or the like, and a throttle opening sensor 14, which senses an opening of the throttle valve 13 (throttle position). Further, each of cylinders of the engine 11 is provided with a fuel injection valve 15 for performing a direct injection or an intake port injection, whereas a cylinder head of the engine 11 has an ignition plug 16 fixed on each of the cylinders. An air-fuel mixture in each of the cylinders is ignited by a spark discharge of each ignition plug 16.

[0048]On the other hand, an exhaust pipe 17 of the engine 11 has a three-way catalyst 18, which cleans CO, HC, and NOx in an emission gas, provided therein and has a NOx storage-reduction cataly...

embodiment 2

[0096]Next, an embodiment 2 of the present disclosure will be described by the use of FIG. 12 and FIG. 13. However, descriptions of the parts substantially identical to those in the embodiment 1 will be omitted or simplified and parts different from those in the embodiment 1 will be mainly described.

[0097]In the present embodiment 2, a three-way catalyst 37 for cleaning CO, HC, and NOx in the emission gas is arranged also downstream of the three-way catalyst 18. Further, an emission gas sensor 20 (air-fuel ratio sensor or oxygen sensor) for sensing an air-fuel ratio of an emission gas or sensing whether an air-fuel ratio of an emission gas is rich or lean is arranged upstream of the three-way catalyst 18, and an oxygen sensor 28, the output voltage of which is reversed depending on whether the air-fuel ratio of the emission gas is rich or lean with respect to a stoichiometric air-fuel ratio, is arranged downstream of the three-way catalyst 18 (between the three-way catalyst 18 and t...

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PUM

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Abstract

In a system having an oxygen sensor arranged downstream of a NOx storage-reduction catalyst, a constant current is made to flow between sensor electrodes by a constant current circuit provided in the outside of the oxygen sensor, which makes it possible to change an output characteristic of the oxygen sensor. Further, during a lean combustion control of an engine, a sensing responsiveness to a lean component of the oxygen sensor is improved. In this way, when NOx (lean component) is emitted to the downstream of the catalyst, the NOx can be quickly sensed by the oxygen sensor. Meanwhile, during a rich combustion control of the engine, the sensing responsiveness to a rich component of the oxygen sensor is improved. In this way, when HC and CO (rich components) are emitted to the downstream of the catalyst, the HC and the CO can be quickly sensed by the oxygen sensor.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is based on Japanese Patent Applications No. 2012-22261 filed on Feb. 3, 2012, and No. 2012-221944 filed on Oct. 4, 2012, the disclosures of which are incorporated herein by reference.TECHNICAL FIELD[0002]The present disclosure relates to an emission gas cleaning device of an internal combustion engine which has a catalyst for cleaning an emission gas of the internal combustion engine and which has an emission gas sensor arranged downstream of the catalyst or in the catalyst.BACKGROUND ART[0003]In an emission gas cleaning system of an internal combustion engine, for example, as described in Patent Literature 1 (Japanese Patent No. 399759), there is proposed the following emission gas cleaning system: that is, an exhaust pipe has a catalyst (for example, a three-way catalyst or a NOx storage-reduction catalyst) arranged therein and has an emission gas sensor (an air-fuel ratio sensor or an oxygen sensor) arranged upstream o...

Claims

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Application Information

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IPC IPC(8): F01N11/00F01N3/20
CPCF01N3/20F01N11/007F01N3/0842F01N3/101F01N2560/025G01N27/4065F02D41/0235F02D41/0275F02D41/1439F02D41/1454F02D41/1476B01D53/30B01D53/9422B01D53/9431B01D53/9445B01D53/9477F01N13/009Y02T10/12G01N27/409B01D53/94F01N3/08F01N3/24F01N3/00
Inventor YOKOI, MASAHIROMATSUOKA, MIKIYASUNAKATA, SHINGO
Owner DENSO CORP