System and method for reducing vehicle acceleration during engine transitions

A method for controlling an engine having multiple cylinders, each with at least one electrically actuated valve, the engine operating in a first mode having a first number of firing cylinders and a second mode having a second number of firing cylinders greater than said first mode, the method comprising:

• when transitioning the engine from operating in the first mode to the second mode and maintaining average torque substantially constant;
• operating a last cylinder in said first mode to be a non-firing cylinder;
• operating a first cylinder in said second mode to be a firing cylinder with an increased torque relative to the average torque output by adjusting valve operation of an electrically actuated valve of the first cylinder in said second mode;
• and
• when transitioning the engine from operating in the second mode to the first mode and maintaining average torque substantially constant;
• operating a last cylinder in said second mode to be a firing cylinder;
• operating a first cylinder in said first mode to be a firing cylinder, where a torque output of said first cylinder in said first mode is reduced relative to the average torque output by adjusting valve operation of an electrically actuated valve of the first cylinder in said first mode.

A system for a vehicle, comprising:

• an engine having multiple cylinders, each with at least one electrically actuated valve, the engine operating in a first mode having a first number of firing cylinders and a second mode having a second number of firing cylinders greater than said first mode;
• a torque converter coupled to the engine;
• a transmission coupled to the torque converter;
• and
• a controller for controlling engine operation, where when transitioning the engine from operating in the first mode to the second mode and maintaining average torque substantially constant, the controller operates a last cylinder in said first mode to be a non-firing cylinder and operates a first cylinder in said second mode to be a firing cylinder with an increased torque relative to the average torque output by adjusting valve operation of an electrically actuated valve of the first cylinder in said second mode;
• and when transitioning the engine from operating in the second mode to the first mode and maintaining average torque substantially constant, the controller operates a last cylinder in said second mode to be a firing cylinder, and operates a first cylinder in said first mode to be a firing cylinder, where a torque output of said first cylinder in said first mode is reduced relative to the average torque output by adjusting valve operation of an electrically actuated valve of the first cylinder in said first mode, the controller further adjusting torque transmission of the torque converter during transitions.