Reduced torque variation for engines with active fuel management

An internal combustion engine comprising:

• a first set of cylinders;
• a second set of cylinders;
• a fuel supply line and an air intake for each cylinder of the first and second sets of cylinders;
• a supplemental gas supply line for each cylinder of the second set of cylinders;
• and
• a controller communicably coupled to the supplemental gas supply line, wherein the controller is configured to perform a method, the method comprising:
• stopping a fuel flow into the first set of cylinders, the stopping causing a deactivation of the first set of cylinders;
• continuing injection of fuel into the second set of cylinders to provide power while the first set of cylinders are deactivated;
• and
• injecting gas, via the supplemental gas supply lines, into the first set of cylinders when each of the first set of cylinders are at bottom dead center, the injected gas increasing a cylinder pressure in each of the first set of the plurality of cylinders that reduces an amplitude of first order torque variations during operation of the engine while the first set of the plurality of cylinders are deactivated.

A method for active fuel management in an engine having a plurality of cylinders, the method comprising:

• stopping a fuel flow into a first set of the plurality of cylinders, the stopping causing a deactivation of the first set of the plurality of cylinders;
• continuing injection of fuel into a second set of the plurality of cylinders to provide power while the first set of the plurality of cylinders are deactivated;
• injecting air into the first set of the plurality of cylinders to increase a cylinder pressure in each of the first set of the plurality of cylinders to reduce an amplitude of first order vibration during operation of the engine while the first set of the plurality of cylinders are deactivated;
• and
• adjusting a firing interval of the first set and second set of the plurality of cylinders to further reduce the amplitude of first order vibrations.