Gm Global Technolgoy Operations, Inc.

Timothy J Holbert

Janean Kowalkowski

Eric M Sisco

Scott Alan Westfall

A control method and system for monitoring a selective catalytic reduction ('SCR') device of an exhaust gas treatment system is disclosed. The method includes monitoring a plurality of operating conditions related to determining an efficiency of the SCR device and a SCR temperature. The method includes determining if each of the operating conditions are within a respective predetermined range and if the SCR temperature is below an operating temperature range. The method includes activating a hydrocarbon supply based on if each of the operating conditions are within the respective predetermined range and if the SCR temperature is below the operating temperature range. The hydrocarbon supply is located upstream of the SCR device to generate heat if activated. The method includes monitoring the SCR temperature to determine if the SCR device is operating within the operating temperature range.

Heat generation system for determining a selective catalytic reduction device efficiency

A vehicle that includes an engine, an exhaust system, and a controller, and a method are disclosed herein. The exhaust system includes a passage for directing the exhaust gas stream from the engine through the series of exhaust after-treatment devices, including a selective-catalytic reduction device and a diesel particulate filter (DPF). The exhaust after-treatment devices are employed to reduce various exhaust emissions of the engine. The exhaust system, may however, prematurely return failing emissions results due to the amount of contaminants that have flowed through the exhaust system since the last regeneration even of the particulate filter. Therefore, the controller may, via the present method, alter the threshold of the SCR efficiency diagnostic due to contaminants accumulated on the DPF and selectively enable or disable the diagnostic based on a set of recorded instructions, to improve the robustness of the SCR efficiency diagnostic and prevent inaccurate failing emissions results.

Method and system for selectively enabling and disabling a diagnostic monitor of a selective-catalytic-reduction device

A method of starting an internal combustion engine includes sensing a temperature of an engine coolant at an engine block of the internal combustion engine, and sensing a temperature of a secondary engine component remote from the engine block when the internal combustion engine is not running. A numerical difference between the temperature of the engine coolant and the temperature of the secondary engine component is calculated. A start parameter setting used to control the start of the internal combustion engine is adjusted based upon both the sensed temperature of the engine coolant and the numerical difference between the sensed temperature of the engine coolant and the sensed temperature of the secondary engine component.

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Clarkston, MI, United States of America

Timothy J Holbert