Skip fire internal combustion engine control

A method of determining firings during operation of an engine in a skip fire operational mode, the method comprising:

• receiving an input signal indicative of a desired engine output;
• determining a skip fire firing sequence that delivers the desired engine output;
• providing a feedback signal indicative of working chamber firings;
• and
• filtering the feedback signal to provide an indication of frequency components of the firing sequence in a selected frequency range;
• and
• wherein the filtered feedback signal is used in the determination of the firing sequence to help reduce the generation of firing sequences that contain frequency components in the selected frequency range.

A method of determining firings during operation of an engine in a skip fire operational mode, the method comprising:

• providing a feedback signal indicative of actual or requested working chamber firings;
• filtering the feedback signal using a band-pass filter to provide an indication of frequency components contained within the firing sequence in a selected frequency range;
• and
• utilizing the filtered feedback signal to help reduce the generation of firing sequences that contain frequency components in the selected frequency range.

A skip fire engine controller comprising a control block arranged to determine a skip fire firing sequence that delivers a desired output, wherein the control block includes:

• a plurality of stages;
• first pole associated with a first one of the stages and arranged to help suppress noise in at least a first frequency range;
• a second pole associated with a second one of the stages and arranged to help suppress noise in at least a second frequency range, wherein the first and second frequency ranges may be either coextensive or not coextensive;
• and
• a feed-forward zero arranged at least in part to help compensate for delay between the generation of a firing request and the realization of torque associated with an actual firing that corresponds to the firing request.

A skip fire controller arranged to direct working chamber firings during operation of an engine in a skip fire operational mode, the controller comprising:

• a control block that receives an input signal indicative of a desired output and is arranged to dynamically determine working chamber firings that deliver the desired output;
• and
• a filter arranged to filter a feedback signal to provide a filtered feedback signal, wherein the frequency characteristics of the filter are variable;
• and
• wherein the control block is arranged to utilize the filtered feedback signal in the determination of the working chamber firings.

A method of determining firings during operation of an engine in a skip fire operational mode, the method comprising:

• receiving an input signal indicative of a desired engine output;
• selectively determining working cycles to be fired and working cycles to be skipped, wherein the fired working cycles are arranged to deliver the desired engine output;
• and
• filtering a feedback signal, wherein the filtered feedback signal is used in the determination of the firings and wherein the frequency characteristics of the filter are varied during operation of the engine in the skip fire operational mode.