Precombustion-chamber type gas engine and operation control method of same

A method of controlling operation of a precombustion-chamber type gas engine which comprises:

• a main chamber defined between a piston and a cylinder head;
• a precombustion chamber which is in communication with the main chamber via an injection nozzle;
• a precombustion-chamber gas supply passage capable of supplying fuel gas to the precombustion chamber from a supply source of the fuel gas not via the main chamber;
• a check valve disposed in the precombustion-chamber gas supply passage;
• and
• a supply pressure control valve which is disposed on an upstream side of the check valve in the precombustion-chamber gas supply passage and which is capable of adjusting a pressure of the fuel gas to be supplied to the precombustion chamber,
• the method comprising:
• a torch strength information acquisition step of obtaining torch strength information correlated to strength of a torch from the injection nozzle, on the basis of a pressure in the main chamber and a pressure in the precombustion chamber;
• a precombustion-chamber gas supply amount calculation step of calculating an amount of the fuel gas to be supplied to the precombustion chamber from the precombustion-chamber gas supply passage (hereinafter, referred to as precombustion-chamber gas supply amount), on the basis of the torch strength information obtained by the torch strength information acquisition device and correlation information representing a correlation between the torch strength information, a thermal efficiency, and the precombustion-chamber gas supply amount;
• and
• a precombustion-chamber gas supply pressure control step of controlling the supply pressure control valve on the basis of the precombustion-chamber gas supply amount calculated in the precombustion-chamber gas supply amount calculation step.