PURPOSE: To realize the stable high efficiency of the internal combustion engine by detecting the pressure drop in a compressed air reservoir to be caused by the use of the compressed air, introducing the signal to an opening/closing adjustment mechanism of an air intake valve, and quickening the timing of closing in the compression stroke of the air intake valve by the opening/closing adjustment mechanism.
CONSTITUTION: The compressed air is stored in a compressed air reservoir 1 by using the night power to drive a compressor. When a generator is driven by operating a reciprocating internal combustion engine 9 in the daytime, the air is fed by operating a control valve 5 mounted on a piping 6. The pressure in the compressed air reservoir 1 is detected by a pressure detector 2, and the signal V is transmitted to a control device 27 to control an opening/closing adjustment mechanism 19. When the compressed air in the compressed air reservoir 1 is comsumed by the internal combustion engine 9 and the pressure is gradually reduced, the pressure drop is detected by the pressure detector 2, the signal is introduced to the control device 27, a cam mechanism 18 of the opening/closing adjustment mechanism 19 is moved to a small diameter part to quicken the closing timing of an air intake valve 10a to make the air volume to be fed to the cylinder 12 constant.
