METHOD FOR ON-BOARD DIAGNOSIS OF AN OXIDATION CATALYST IN AN EXHAUST-GAS SYSTEM OF AN INTERNAL COMBUSTION ENGINE OF A VEHICLE

摘要

A method for on-board diagnosis of an oxidation catalyst in an exhaust-gas system of an internal combustion engine of a vehicle having an engine control device and a temperature sensor in the exhaust gas system upstream from a downstream side of said oxidation catalyst. The method includes operating the internal combustion engine is in an overrun mode, and injecting a quantity of fuel upstream from the oxidation catalyst. The change of temperature values over time is measured by the temperature sensor, and at least one physical quantity that characterizes the heat release in said oxidation catalyst is calculated on the basis of said amount of injected fuel. The method further includes ascertaining whether the calculated quantity falls within a set of values, and, if so, declaring that said oxidation catalyst is considered to be defective.

主权项

1. A method for on-board diagnosis of an oxidation catalyst in an exhaust-gas system of an internal combustion engine of a vehicle, wherein the vehicle has an engine control device and a temperature sensor located in the exhaust gas system upstream from a downstream side of said oxidation catalyst, said method comprising the following steps:
operating said internal combustion engine in an overrun mode; injecting an amount of fuel upstream from said oxidation catalyst; measuring, via said temperature sensor, a change of temperature values over time; calculating, via said engine control device, at least one physical quantity that characterizes a heat release in said oxidation catalyst on the basis of said amount of injected fuel; determining, via said engine control device, whether the calculated quantity falls within a set of values; and declaring, via said engine control device, that said oxidation catalyst is defective if the calculated quantity falls within the set of values.