Gm Global Technolgoy Operations, Inc.

GuoJun Shi

Wenbo Wang

Richard B Jess

Chuan He

Jay Tolsma

Matthew J Roelle

Benjamin D Ellies

Michael Denny Parr

Mark E Johnston

Jose L DeLeon

Kouji Sakumoto

A temperature sensor rationality control system for an exhaust treatment system having an oxidation catalyst includes an oxidation catalyst inlet temperature sensor that generates an inlet temperature signal and an oxidation catalyst outlet temperature sensor that generates an outlet temperature signal. A control module determines whether a difference based on the inlet temperature signal and the outlet temperature signal is below a difference threshold when an exhaust temperature is within a threshold range.

Diesel oxidation catalyst (DOC) temperature sensor rationality diagnostic

Methods and apparatus for accurately predicting a fuel injector tip temperature (FITT) are described. One technique for predicting the temperature of a fuel injector tip in an engine suitably includes the steps of estimating an initial temperature of the fuel injector tip and calculating a steady state temperature of the fuel injector tip. A filter coefficient is determined as a function of a rate of airflow into the engine, and the temperature of the fuel injector tip is predicted as a function of said initial temperature, the steady state temperature, and the filter coefficient. In a further embodiment, the steady state temperature is filtered into a feedback temperature at a rate that is determined by the filter coefficient.

Method and apparatus for predicting a fuel injector tip temperature

Method and apparatus to monitor secondary air injection and catalyst conversion efficiency. The method includes operating an engine in a rich condition after detecting an engine steady state condition. The secondary air injector injects air into an exhaust stream to simulate a lean engine condition. The injection of the air into the exhaust stream is ceased after both inlet and outlet sensors detect the lean condition. After ceasing air injection, a lag time is determined between the inlet sensor detecting the rich condition and the outlet sensor detecting the rich operating condition. An oxygen storage capacity of the catalytic converter is calculated based on the lag time. An efficiency of the catalytic converter is determined as a function of the storage capacity. Additionally, performance of the secondary air injector is monitored. If the inlet sensor fails to detect the lean condition after the secondary air injector is active, a fault is signaled.

Method and apparatus for monitoring catalyst efficiency and secondary air injection

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Canton, MI, United States of America

GuoJun Shi