Vibration isolation system and method for engine, and control system and method for active vibration isolation support system

An engine vibration isolation method comprising the steps of:

• supporting, on a vehicle body via an active vibration isolation support system, an engine that can switch among an all-cylinder running, a first modified running and a second modified running, wherein said first modified running and said second modified running differ from one another in the number of cylinders that are cut off;
• and
• controlling, via a control portion, an actuator of the active vibration isolation support system according to a vibrational state of the engine so as to suppress transmission of vibration from the engine to the vehicle body,
• wherein the method further comprises the steps of:
• carrying out the first modified running in a first period;
• carrying out, in a transitional period subsequent to the first period, all-cylinder running in which all the cylinders are in operation;
• and
• carrying out the second modified running in a second period subsequent to the transitional period;
• and
• wherein when the ratio of the order of vibration of the first modified running and the order of vibration of the second modified running is not an integer, the control portion interposes the all-cylinder running.

A control method for an active vibration isolation support system, comprising the steps of:

• supporting, on a vehicle body via the active vibration isolation support system, an engine that carries out cylinder cut-off running which combines one cylinder cut-off period and two combustion periods in one cycle;
• and
• controlling, via a control portion, an actuator of the active vibration isolation support system according to a vibrational state of the engine so as to suppress transmission of vibration from the engine to the vehicle body,
• wherein the one cylinder cut-off period starts at the same time as when starting one cycle of reading in the engine vibrational state during the cylinder cut-off running, and the two combustion periods follow.

A control method for an active vibration isolation support system, comprising the steps of:

• supporting, on a vehicle body via the active vibration isolation support system, an engine that carries out cylinder cut-off running which combines one cylinder cut-off period and two combustion periods in one cycle;
• and
• controlling, via a control portion, an actuator of the active vibration isolation support system according to a vibrational state of the engine so as to suppress transmission of vibration from the engine to the vehicle body,
• wherein the engine vibrational state is calculated by filter calculation of a crank angular velocity based on rotational variation of a crankshaft using a differential filter, a series of the two combustion periods is started at the same time as when starting one cycle of reading in the engine vibrational state during the cylinder cut-off running, and the one cylinder cut-off period follows.