Nvh management in diesel cda modes

A method for entering and exiting cylinder deactivation modes in a four cylinder diesel engine, comprising:

• monitoring an engine speed from an idle engine speed to a governed engine speed;
• monitoring an engine load;
• if the monitored engine speed is a governed engine speed or if the monitored engine load is greater than a predetermined low load condition, then full engine operation is implemented and cylinder deactivation modes are exited, or then the engine operation is restricted from entering any cylinder deactivation mode but a coast operation mode;
• if the monitored engine speed is the idle engine speed up to the governed engine speed, and if the engine load is less than the predetermined low load condition, then implementation of a cylinder deactivation mode is restricted to one of a one cylinder deactivation mode, a two cylinder deactivation mode, or a three cylinder deactivation mode;
• and
• selecting a cylinder deactivation mode for engine operation among the one cylinder deactivation mode, the two cylinder deactivation mode, and the three cylinder deactivation mode to operate the engine at an effective frequency that avoids two resonant frequencies of the vehicle and to operate the engine below a torsional vibration limit.

A method for calibrating an engine for switching among cylinder deactivation modes, comprising:

• motoring the engine through speed sweeps and load sweeps;
• calibrating a first resonant frequency at a first engine mount;
• calibrating a second resonant frequency at either a second engine mount or at a flywheel of the engine;
• programming control electronics of the engine to monitor and engine load and an engine speed;
• and
• programming control electronics of the engine to select a cylinder deactivation mode for engine operation among a 2 cylinder deactivation mode, a 3 cylinder deactivation mode, and a 4 cylinder deactivation mode to operate the engine at an effective frequency that avoids two resonant frequencies of the vehicle and to operate the engine below a torsional vibration limit when a monitored engine speed is between an idle engine speed up to a governed engine speed, and when a monitored engine load is less than a predetermined low load condition.

A method for entering and exiting cylinder deactivation modes in a diesel engine, comprising:

• monitoring an engine speed from an idle engine speed to a governed engine speed;
• monitoring an engine load;
• if the monitored engine speed is a governed engine speed or if the monitored engine load is greater than a predetermined low load condition, then full engine operation is implemented and cylinder deactivation modes are exited, or then the engine operation is restricted from entering any cylinder deactivation mode but a coast operation mode;
• if the monitored engine speed is the idle engine speed up to the governed engine speed, and if the engine load is less than the predetermined low load condition, then implementation of a cylinder deactivation mode is restricted to one of a 2 cylinder deactivation mode, a 3 cylinder deactivation mode, or a 4 cylinder deactivation mode;
• and
• selecting a cylinder deactivation mode for engine operation among the 2 cylinder deactivation mode, the 3 cylinder deactivation mode, and the 4 cylinder deactivation mode to operate the engine so as to limit the acceleration of the engine in a lateral linear direction and to operate the engine below a torsional vibration limit.