Internal combustion engine and power generation system

An internal combustion engine, comprising:

• an internal combustion engine main body including a plurality of cylinders;
• a plurality of knock sensors being provided on each of the plurality of cylinders;
• a control board including same number of amplification circuits as the plurality of cylinders;
• and
• a plurality of cables differing in length and each connecting each of the knock sensors and the control board, each of the plurality of cables having different capacitance;
• wherein each of the amplification circuits includes a first charge amplifier, a second charge amplifier, a differential amplifier, a gain amplifier, and a bandpass filter,
• wherein the first charge amplifier includes a first operational amplifier, a first resistor, a second resistor, and a first capacitor;
• the second charge amplifier includes a second operational amplifier, a third resistor, a fourth resistor, and a second capacitor;
• the differential amplifier includes a third operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, and a eighth resistor;
• and
• the gain amplifier includes a fourth operational amplifier, a ninth resistor, a tenth resistor, and an eleventh resistor;
• wherein a first terminal of the first resistor is connected to a non-inverting input terminal of the first operational amplifier;
• a first terminal of the second resistor and a first terminal of the first capacitor are connected to an inverting input terminal of the first operational amplifier;
• a second terminal of the second resistor and a second terminal of the first capacitor are connected to an output terminal of the first operational amplifier;
• a ground is connected to a second terminal of the first resistor;
• a first terminal of the third resistor is connected to a non-inverting input terminal of the second operational amplifier;
• a first terminal of the fourth resistor and a first terminal of the second capacitor are connected to an inverting input terminal of the second operational amplifier;
• a second terminal of the fourth resistor and a second terminal of the second capacitor are connected to an output terminal of the second operational amplifier;
• the ground is connected to a second terminal of the third resistor;
• a first terminal of the fifth resistor and a first terminal of the sixth resistor are connected to a non-inverting input terminal of the third operational amplifier;
• a first terminal of the seventh resistor and a first terminal of the eighth resistor are connected to the an inverting input terminal of the third operational amplifier;
• a second terminal of the eighth resistor is connected to an output terminal of the third operational amplifier;
• an output terminal of the first charge amplifier is connected to a second terminal of the fifth resistor;
• the ground is connected to a second terminal of the sixth resistor;
• an output terminal of the second charge amplifier is connected to a second terminal of the seventh terminal;
• a first terminal of the ninth resistor is connected to a non-inverting input terminal of the fourth operational amplifier;
• a first terminal of the tenth resistor and a first terminal of the eleventh resistor are connected to an inverting input terminal of the fourth operational amplifier;
• a second terminal of the tenth resistor is connected to an output terminal of the fourth operational amplifier;
• the ground is connected to a second terminal of the ninth resistor;
• an output terminal of the differential amplifier is connected to a second terminal of the eleventh resistor;
• an output terminal of the gain amplifier is connected to a first terminal of the bandpass filter;
• the bandpass filter is configured to output, from a second terminal of the bandpass filter, only a signal of a predetermined frequency component in a signal output by the differential amplifier, as an output signal of each of the amplification circuits;
• an input terminal of the first charge amplifier is connected to a corresponding cable of the plurality of cables and an input terminal of the second charge amplifier is connected to another corresponding cable of the plurality of cables, the number of the plurality of cables being the twice number of the plurality of cylinders;
• and
• each of the plurality of knock sensors is connected to one of the plurality of cables, the one of the plurality of cables being connected to a corresponding amplification circuit of the amplification circuits, the number of the amplification circuits being the same as the number of the plurality of cylinders.