Gas engine drive system

A gas engine drive system comprising:

• a gas engine;
• a turbocharger including a compressor and a turbine that are connected to the gas engine;
• a fuel injection valve provided on the gas engine;
• a fuel supply line that leads a fuel gas to the fuel injection valve, the fuel supply line being provided with a pressure regulating valve;
• a first pressure meter that detects an intake air pressure that is a pressure of intake air fed from the compressor to the gas engine;
• a second pressure meter that detects a fuel supply pressure that is a pressure at a downstream side of the pressure regulating valve;
• and
• a controller that controls the pressure regulating valve such that a pressure difference between the fuel supply pressure detected by the second pressure meter and the intake air pressure detected by the first pressure meter is a target value, wherein
• the controller changes the target value from a first setting value to a second setting value higher than the first setting value when the controller determines by any one of (i) a first determination method, (ii) a second determination method, and (iii) a third determination method that a load on the gas engine increases rapidly,
• the first determination method includes:
• calculating a speed of increase in a necessary fuel injection amount;
• and
• determining that the load on the gas engine increases rapidly if the speed of increase in the necessary fuel injection amount is higher than a threshold, and determining that the load on the gas engine does not increase rapidly if the speed of increase in the necessary fuel injection amount is lower than the threshold,
• the second determination method includes:
• calculating a deviation between an actual rotational speed and a target rotational speed;
• and
• determining that the load on the gas engine increases rapidly if the deviation between the actual rotational speed and the target rotational speed is greater than a threshold, and determining that the load on the gas engine does not increase rapidly if the deviation between the actual rotational speed and the target rotational speed is less than the threshold, and
• the third determination method includes:
• detecting an output torque of the gas engine by a torque meter and calculating a speed of increase in the output torque;
• and
• determining that the load on the gas engine increases rapidly if the speed of increase in the output torque is higher than a threshold, and determining that the load on the gas engine does not increase rapidly if the speed of increase in the output torque is lower than the threshold.