System and method of controlling maximum hydrocarbon injection for diesel particulate filter regeneration

摘要

A method of providing hydrocarbons to an engine exhaust for regenerating a diesel particulate filter within an exhaust system of a diesel engine. A mass flow rate of exhaust gas within an exhaust system is determined. A mass flow rate of oxygen within the exhaust gas entering the diesel oxidation catalyst is determined. A set point indicative of an allowable mass flow rate of oxygen within the exhaust gas exiting the diesel oxidation catalyst is received. A hydrocarbon threshold that may be injected into the exhaust system is calculated. Hydrocarbons are injected into the exhaust system upstream of the diesel oxidation catalyst, wherein the injected hydrocarbons do not exceed the calculated threshold amount of hydrocarbons.

主权项

1. A method of providing hydrocarbons to an engine exhaust for regenerating a diesel particulate filter within an exhaust system of a diesel engine, the diesel engine comprising an electronic control module, at least one cylinder, and a diesel oxidation catalyst within the exhaust system, the method comprising:
determining a mass flow rate of exhaust gas within an exhaust system; determining a mass flow rate of oxygen within the exhaust gas entering the diesel oxidation catalyst; determining a minimum mass flow rate of oxygen within the exhaust gas exiting the diesel oxidation catalyst; receiving a set point indicative of an allowable mass flow rate of oxygen within the exhaust gas exiting the diesel oxidation catalyst; calculating a hydrocarbon threshold for injecting into the exhaust system based upon the mass flow rate of exhaust gas within the exhaust system, the mass flow rate of oxygen within the exhaust gas entering the diesel oxidation catalyst, and the minimum mass flow rate of oxygen within the exhaust gas exiting the diesel oxidation catalyst; calculating an amount of hydrocarbons required to raise a temperature of the diesel particulate filter to a pre-set temperature for regeneration; comparing the amount of hydrocarbons required to raise the temperature of the diesel particulate filter to the hydrocarbon threshold determined to be injected into the exhaust system based upon the mass flow rate of exhaust gas within the exhaust system, the mass flow rate of oxygen within the exhaust gas entering the diesel oxidation catalyst, and the minimum mass flow rate of oxygen within the exhaust gas exiting the diesel oxidation catalyst; injecting an amount of hydrocarbons equal to the lesser of the amount of hydrocarbons required to raise a temperature of the diesel particulate filter to a pre-set temperature for regeneration and a maximum amount of hydrocarbons determined to be injected into the exhaust system based upon the mass flow rate of exhaust gas within the exhaust system, the mass flow rate of oxygen within the exhaust gas entering the diesel oxidation catalyst, and the minimum mass flow rate of oxygen within the exhaust gas exiting the diesel oxidation catalyst.