Improvements in and relating to the operation of internal combustion engines

213,570. Seiliger, M. March 26, 1923, [Convention date]. Cylinders, varying clearance of; four-strokecycle engines.-Engines which are supplied with charging air from a compressor have the clearance variable to maintain constant compression ratio in the cylinder, the variation in the clearance and the adjustment of compressor pressure being regulated by hand. As shown applied to a four-stroke Diesel engine, a piston 12 is used in an additional clearance space 11. The piston 12 is connected through chain gear to a counterweight; the position of the piston is varied by adjusting the quantity of fluid contained in the space 18 behind the piston. The compressor supplying the air is driven from the engine through a clutch which may be opened to allow the engine to work without pre-compressed air. The regulating handles for the compressor suction and for the control of the fluid in the space 18, together with a manometer for the compressor delivery and an indicator for the counterweight, are mounted on a single control board. The adjustable piston may be in the main cylinder. The Specification as open to inspection under Sect. 91 (3) (a) states that the cylinder cover can be adjusted to vary the clearance. This subjectmatter does not appear in the Specification as accepted.