GB473288A - An improved internal-combustion engine - Google Patents

Abstract

473,288. Driving gear for variablecompression-ratio engines. HELMORE, W., and GRIFFITH, A. A. April 8, 1936, No. 10291. [Class 7 (ii)] Adjacent cylinders 12, 13 having a common combustion chamber 19 contain pistons connected to separate crank or equivalent shafts which are geared together to rotate at the same number of revolutions per minute. For varying the phase of the crank-shafts, and thereby the compression-ratio, during running epicyclic gearing is arranged within the gearwheels 35. Each crank-shaft carries a sunpinion 25 in gear with a planet-pinion 26, the carrier 28 of which is externally formed with the gear-track 35. A further sun-pinion is mounted on a spindle 30 carrying a lever 32. The levers associated with each pair of crankshafts are connected by a link 33 for joint adjustment by a servomotor 54 responsive to oil-pressure, and controlled by a capsule 61 in communication with the engine induction pipe and by a rod 66 connected to the carburetter mixture control. With the linkage set as shown in Fig. 5 for maximum compression ratio, the torque reactions are equal and opposite and balance one another. In out-ofphase settings where the torque reactions on the two sun-wheels are unequal, the forces transmitted to the member 34 may still be balanced due to the unsymmetrical position of the members 32 and link 33. Where the engine cylinders are arranged side-by-side they are inclined to reduce the size of the combustion chamber, the inclined cylinder axes passing through the axes of the crank-shafts. The cylinders may, however, be placed end-to-end with a central combustion chamber, and crankshafts at each end, rotating oppositely and geared together by intervening wheels. Sleeve valves may be used.