Managing torque delivery during dynamic fuel management transitions

An engine control system arranged to direct dynamically fuel management of an engine, the engine control system having at least one controller configured to:

• operate the engine at a first firing fraction, a first cam phase, and a first throttle control position;
• determine a desired second firing fraction and a desired second cam phase, the desired second firing fraction being different than the first firing fraction;
• determine a torque request;
• determine a throttle area;
• determine a desired second throttle control position based on at least the throttle area, the torque request, the desired second firing fraction, and the desired second cam phase;
• and
• complete a firing fraction transition from the first firing fraction to the desired second firing fraction while completing a throttle transition from the first throttle control position to the desired second throttle control position, wherein each of the firing fraction transition and the throttle transition are completed with a predetermined relationship with respect to each other by constantly maintaining a proportional relationship between a delivered firing fraction and a manifold pressure during the entire firing fraction transition.

A vehicle system comprising:

• an engine having a plurality of pistons, each piston slidable within a cylinder bore, and a cam configured to control the flow of air and fuel into each cylinder bore;
• a throttle configured to control a flow of fluid into the engine;
• and
• a control system having at least one controller configured to:
• operate the engine at a first firing fraction, the cam at a first cam phase, and the throttle at a first throttle control position;
• determine a desired second firing fraction and a desired second cam phase, the desired second firing fraction being different than the first firing fraction;
• determine a torque request;
• determine a throttle area through the throttle, the throttle area being selectively variable;
• determine a desired second throttle control position based on at least the throttle area, the torque request, the desired second firing fraction, and the desired second cam phase;
• and
• complete a firing fraction transition from the first firing fraction to the desired second firing fraction while completing a throttle transition from the first throttle control position to the desired second throttle control position, wherein each of the firing fraction transition and the throttle transition are completed with a predetermined relationship with respect to each other by constantly maintaining a proportional relationship between a delivered firing fraction and a manifold pressure during the entire firing fraction transition.