Gm Global Technolgoy Operations, Inc.

Raffaele Esposito

Michael A Smith

Charles E Dean

Giovanni Montinaro

Umberto Ferrara

Alberto Giordano

Giacomo Latrofa

Tiziana Belvedere

Luca Chiapusso

Marco Tiberio

An internal combustion engine fluidly coupled to an exhaust aftertreatment system that includes an exhaust purifying device is described. A pressure monitoring device is disposed to monitor a pressure differential between an inlet and an outlet of the exhaust purifying device. A method of monitoring the exhaust purifying device includes monitoring a pressure differential between an inlet and an outlet thereof, and determining an exhaust gas flowrate associated with operation of the internal combustion engine. A raw flow resistance is dynamically determined based upon the pressure differential and the exhaust gas flowrate, and an estimated flow resistance is determined based upon the raw flow resistance. The exhaust purifying device is evaluated based upon the estimated flow resistance.

Method and apparatus for monitoring flow resistance in an exhaust aftertreatment system

Exhaust gas systems includes an oxidation catalyst (OC) capable of receiving exhaust gas and oxidizing one or more of combustable hydrocarbons (HC) and one or more nitrogen oxide (NOx) species, a selective catalytic reduction device (SCR) disposed downstream from and in fluid communication with the OC, an upstream NOx sensor disposed upstream from the SCR, and a downstream NOx sensor disposed downstream from the SCR. Methods for controlling systems include providing exhaust gas to the OC and subsequently the SCR, measuring an upstream exhaust gas NOx concentration, measuring a downstream exhaust gas NOx concentration, determining a NOx differential by subtracting the downstream exhaust gas NOx concentration from the upstream exhaust gas NOx concentration; and comparing the NOx differential to a differential threshold to determine OC catalytic performance. The method is conducted under while OC is above a NOx to NH3 conversion yield threshold, and/or under rich conditions.

Methods for controlling and monitoring oxidation catalyst devices

Methods for monitoring thermal characteristics of oxidation catalyst (OC) catalytic composition(s) (CC) are provided, and comprise communicating exhaust gas to the OC, and determining a temperature change of the CC for the time frame based on a plurality of heat sources including heat imparted to the CC from exhaust gas enthalpy, heat imparted to the CC via oxidation of HC and/or CO in exhaust gas, heat imparted to the CC via water present in the exhaust gas condensing on the CC or heat removed from the CC via water evaporating from the CC, and optionally heat exchanged between the CC and the ambient environment. Heat imparted to the CC via water condensing on the CC can be determined using an increasing relative humidity proximate the CC, and heat removed from the CC via water evaporating from the CC can be determined using a decreasing relative humidity proximate the CC.

Methods for monitoring and modelling thermal characteristics of oxidation catalyst devices

Methods and apparatuses are provided for detecting a defective internal clock signal. A signal transformer receives a clock signal having a duty cycle and a frequency and converts with the signal transformer the clock signal into a monitoring signal having a peak value related to the duty cycle and to the frequency of the clock signal. A detector is connected to the signal transformer to receive the monitoring signal and generates an error signal when the peak value of the monitoring signal is outside a predefined range.

Clock signal monitoring apparatus and method

A method and apparatus are disclosed for detecting a clogging of a fuel injector of an internal combustion engine. Each fuel injector of the plurality of fuel injectors may be tested for a clogging. A test injector is switch off. A requested value of a fuel quantity to be injected by the other fuel injectors of the plurality of fuel injectors is adjusted to operate the internal combustion engine in an idle mode. A difference is calculated between the requested value of the fuel quantity and a reference value of the fuel quantity to be injected by all the fuel injectors of the plurality of fuel injectors to operate the internal combustion engine in idle mode. The calculated difference for each test injector is used to identify if the test injector is clogged.

Method of detecting a clogging of a fuel injector in an internal combustion engine

A method is provided for operating a compression-ignition engine having a combustion chamber. The method includes establishing, via an injection driver, electronic communication with a primary clock configured to generate a primary time signal. The method also includes commanding an injector to introduce into the combustion chamber injections of fuel having respective pulse widths timed using the primary time signal to generate combustion within the combustion chamber. The method additionally includes detecting a loss of the primary time signal and subsequently establishing an electronic communication between the injection driver and an auxiliary clock configured to generate an auxiliary time signal. Furthermore, the method includes commanding the injector to introduce into the combustion chamber a number of injections of fuel having respective pulse widths timed using the auxiliary time signal and thereby continuing combustion within the combustion chamber. A vehicle employing the injection driver for executing the method is also provided.

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Siano, Italy

Raffaele Esposito