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Method for sensing exhaust gas for OBD

a technology of exhaust gas and sensing method, which is applied in the direction of electrical control, machines/engines, mechanical apparatus, etc., can solve the problems that the sensors for pm (particulate matter), hc (hydrocarbon) and co (carbon monoxide) cannot be mounted in the vehicl

Inactive Publication Date: 2005-09-29
HINO MOTORS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention is a method for sensing exhaust gas for OBD (on-board diagnostics) that uses a NOx sensor to detect NOx concentration in the exhaust gas. The NOx sensor also picks up O2 concentration in the exhaust gas, which is used to determine the concentrations of PM (particulate matter), HC (hydrocarbons), and CO (carbondioxides) in the exhaust gas. By measuring these concentrations, the method allows for the determination of all the necessary information for OBD. Additionally, the method takes into account the fact that the PM, HC, and CO concentrations in the exhaust gas are influenced by the O2 concentration. The method also compensates for the purified ratios of the PM, HC, and CO concentrations based on the catalytic activity of the oxidation catalyst in the exhaust pipe. This ensures accurate determination of the final values of the PM, HC, and CO concentrations in the exhaust gas.

Problems solved by technology

However, most of conventionally known exhaust-gas sensors are large-sized fixed devices in laboratory level so that, except a NOx sensor which is compact in size and has been actually mounted in a vehicle, sensors for PM (particulate matter), HC (hydrocarbon) and CO (carbon monoxide) concentrations cannot be mounted in a vehicle up to the present.

Method used

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  • Method for sensing exhaust gas for OBD
  • Method for sensing exhaust gas for OBD
  • Method for sensing exhaust gas for OBD

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Embodiment Construction

[0023] Now, an embodiment of the invention will be described with reference to the drawings.

[0024] FIGS. 1 to 7 show an embodiment of a method for sensing exhaust gas for OBD according to the invention in which exhaust gas 3 is discharged via an exhaust manifold 2 from a diesel engine 1 and flows through an exhaust pipe 4. Arranged in the exhaust pipe 4 is a casing 6 which accommodates an oxidation catalyst 5 in the form of a flow-through type honeycomb structure.

[0025] Arranged on a most upstream side in the exhaust pipe 4 is a NOx sensor 8 which is positioned adjacent to a turbine outlet of a turbocharger 7. Arranged on an inlet side of the casing 6 is a temperature sensor 9 which detects temperature of the exhaust gas 3. Detection signals 8a and 9a from the sensors 8 and 9, respectively, are inputted to an electronic control unit (ECU) 10 which is an engine controlling computer.

[0026] When NOx, PM, HC and CO concentrations grasped on the basis of detection signals 8a and 9a fr...

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Abstract

All of NOx, PM, HC and CO concentrations necessary for realization of OBD are determined by utilization of an in-vehicle existing NOx sensor. A NOx sensor arranged in an exhaust pipe detects the NOx concentration in the exhaust gas. On the basis of O2 concentration detected in a course of detection of the NOx concentration, PM, HC and CO concentrations are determined in conversion through mutual correspondences of the concentrations.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for sensing exhaust gas for OBD. [0003] 2. Description of the Related Art [0004] It has been recently proposed to monitor controlled states of exhaust gas from a vehicle by virtue of an in-vehicle computer. It is generally called OBD (on-board diagnostic system); there is an active trend towards future legal compulsion including restrictions for OBD. [0005] Detection of exhaust-gas temperature and NOx (nitrogen oxides) concentration through sensors in a control system for an exhaust purifying or aftertreatment apparatus has been disclosed for example in JP 2002-161732 A. [0006] However, most of conventionally known exhaust-gas sensors are large-sized fixed devices in laboratory level so that, except a NOx sensor which is compact in size and has been actually mounted in a vehicle, sensors for PM (particulate matter), HC (hydrocarbon) and CO (carbon monoxide) concentrations ca...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F02D45/00F01N3/00F01N3/20F01N11/00
CPCF01N3/20F01N11/00Y02T10/47F01N2560/026F01N2560/06F01N11/007Y02A50/20Y02T10/40
Inventor FUNABASHI, HIROSHI
Owner HINO MOTORS LTD