Systems and methods for reducing noise, vibration, and/or harshness during engine shutdown and restart

A method of reducing vibration generated by an internal combustion engine, the method comprising:

• detecting, by an engine control unit (ECU), a condition that causes a transition of an engine speed of the engine from a first engine speed to a second engine speed;
• determining, by the ECU, an engine speed target profile for transitioning the engine speed of the engine, wherein the engine speed target profile specifies a plurality of expected engine speeds at a plurality of points in time following detection of the instruction;
• monitoring, by the ECU, the engine speed of the engine;
• determining, by the ECU, a correction torque to drive the engine speed toward an expected engine speed at a given point in time according to the engine speed target profile;
• and
• causing, by the ECU, an electric motor to apply the correction torque.

A non-transitory computer-readable medium having computer-executable instructions stored thereon that, in response to execution by an engine control unit (ECU), cause the ECU to perform actions for reducing vibration generated by an internal combustion engine, the actions comprising:

• detecting, by the ECU, a condition that causes a transition of an engine speed of the engine from a first engine speed to a second engine speed;
• determining, by the ECU, an engine speed target profile for transitioning the engine speed of the engine, wherein the engine speed target profile specifies a plurality of expected engine speeds at a plurality of points in time following detection of the instruction;
• monitoring, by the ECU, the engine speed of the engine;
• determining, by the ECU, a correction torque to drive the engine speed toward an expected engine speed at a given point in time according to the engine speed target profile;
• and
• causing, by the ECU, an electric motor to apply the correction torque.