Fuel system management during cylinder deactivation operation

A method for operating an engine fueling system to manage fuel in an accumulator supplying fuel to an engine including multiple cylinders, comprising:

• monitoring fuel load in the accumulator, wherein the accumulator is a common rail fuel accumulator connected between a high pressure fuel pump and a plurality of fuel injectors, and the high pressure pump is downstream of a lower pressure pump;
• determining that the engine is operating in a cylinder deactivation mode during which one or more fueling events to one or more of the cylinders is being skipped;
• determining an incremental engine load request in response to at least one of a throttle command, a gear shift operation, and a request to actuate an aftertreatment system during a time period in which a fuel delivery event is being skipped with the engine operating in the cylinder deactivation mode;
• and
• controlling a supply of fuel from the high pressure fuel pump in response to the incremental engine load request and the monitored fuel load in the common rail fuel accumulator during the time period in which fuel delivery is being skipped while operating in the cylinder deactivation mode by:
• causing fuel to be supplied from the high pressure fuel pump to the common rail fuel accumulator if the monitored fuel load is less than or equal to a second load value, wherein the second load value is greater than a first load value that defines an operational load of the common rail fuel accumulator;
• and
• causing fuel from the high pressure fuel pump to be recirculated dumped, or shunted and not be supplied to the common rail fuel accumulator if the monitored fuel load is greater than the second load value.