Gm Global Technolgoy Operations, Inc.

Ignazio Dentici

Michele Bastianelli

Methods and apparatus for operating an internal combustion engine are provided. The engine has an engine block defining a cylinder accommodating a reciprocating piston coupled to rotate a crankshaft, a fuel injector for injecting fuel inside the cylinder, and a crank position sensor positioned proximal to the crankshaft. A method includes commanding the fuel injector to perform a test fuel injection with a predetermined energizing time and using the crank position sensor to determine a crankshaft acceleration signal during the test fuel injection. The crankshaft acceleration signal is filtered and a value of an amplitude of a fundamental frequency component of the filtered crankshaft acceleration signal is determined. A correction factor of the predetermined energizing time is determined based on a difference between the determined value of the amplitude and a preset value thereof. The correction factor is used to correct an energizing time of subsequent fuel injections.

Method for operating an internal combustion engine using a corrected energizing time for fuel injections

A method is provided for controlling a Diesel Emission Fluid (DEF) injected quantity in a NOreduction system employing a Selective Catalytic Reduction (SCR) catalyst, and a DEF injector for injecting the DEF to reach said SCR catalyst. The method includes determining a required quantity of DEF for the SCR catalyst at a given time. If the required quantity of DEF is at least equal to a threshold quantity, then a DEF injection is activated, otherwise the required quantity of DEF is stored in memory of an Electronic Control Unit (ECU). After a period, a further required quantity of DEF to be added to the required quantity is determined to determine a new required quantity of DEF. The new required quantity of DEF is continuously updated until the new required quantity of DEF is at least equal to said threshold quantity, at which point the DEF injection of the new required quantity of DEF is activated.

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Turin, Italy

Ignazio Dentici