Internal combustion engine control for improved fuel efficiency

A drive pulse generator suitable for use in an engine controller arranged to control working chamber firings in an engine, wherein the engine controller has a variable displacement operational mode that causes selected active working cycles to be fired and selected passive working cycles not to be fired, the drive pulse generator comprising:

• an input signal digitizer arranged to receive an analog input signal indicative of a desired engine output and to output a digitizer output signal that is a feedback modified digital representation of the analog input signal;
• and
• a synchronizer arranged to receive the digitizer output signal and to output a drive pulse signal that is synchronized with the engine speed, wherein the drive pulse signal generally indicates when active working cycles are appropriate to deliver the desired engine output;
• and
• wherein feedback indicative of at least one of the drive pulse signal or a firing pattern that is based at least in part on the drive pulse signal is fed back to the input signal digitizer and is used in the generation of the digitizer output signal.

A method of controlling the operation of an internal combustion engine having a plurality of working chambers, each working chamber being generally arranged to operate in a succession of working cycles, the method comprising operating the engine in a variable displacement mode that includes:

• delivering air and fuel to the working chambers during the active working cycles;
• firing the working chambers in a firing pattern dynamically determined on a firing opportunity by firing opportunity basis during operation of the engine that skips the firing of selected skipped working cycles and fires selected active working cycles;
• wherein an amount of air and fuel delivered to the working chambers during a first set of the active working cycles is substantially optimized;
• and
• wherein the firing pattern is determined at least in part using predictive adaptive control to provide a desired engine output, and wherein the predictive adaptive control includes feedback indicative of at least one of requested and actual working cycle firings.

A method of controlling the operation of an internal combustion engine having at least one working chamber, each working chamber being generally arranged to operate in a succession of working cycles, wherein the method comprises operating the engine in a skip fire continuously variable displacement mode that includes:

• generating a drive pulse pattern that is synchronized with firing opportunities of the engine, wherein the drive pulse pattern generally indicates when working cycles need to be fired to deliver a desired engine output;
• generating a firing pattern based at least in part on the drive pulse pattern, wherein the firing pattern is not always the same as the drive pulse pattern;
• and
• firing the at least one working chamber in accordance with the firing pattern, wherein the firing pattern skips the firing of selected skipped working cycles and fires selected active working cycles.