GB397387A - Improvements in or relating to reciprocating engines - Google Patents

Abstract

397,387. Balancing reciprocating engines. SULZER FRERES SOC. ANON., Winterthur, Switzerland. Feb. 14, 1933, No. 4566. Convention date, Feb. 29, 1932. [Class 122 (iii).] In a reciprocating engine, a periodically varying force is applied to the main crank shaft through one or more subsidiary cranks driven by the main engine to balance a harmonic component of the torque applied to the shaft. The cranks may be connected to pistons subjected to fluid pressure, or to weights. In a four cylinder internal-combustion engine, a sinusoidally increasing and decreasing force H is applied to the main crank shaft of the engine so as to oppose the resultant B, Fig. 3, of the harmonic components of the first order represented by the vectors I . . IV of the torque curve of the four cranks. The force H is applied to a subsidiary crank set at an angle a to the engine crank corresponding to the vector IV. In the construction, shown in Fig. 5, the main shaft is connected to a subsidiary shaft with a crank operating a scavenging-air compressor. The desired balancing force is provided by a piston 7 mounted on an extension of the compressor piston-rod which is subjected to the pressure in a chamber 9 above the compressor cylinder 6. A modified arrangement is described wherein balancing pistons are attached to the compressor piston-rod and a compressor valve rod. The forces on the pistons are so arranged that their resultant balances in magnitude and direction the vector resultant of the vectors representing the harmonic components of the torque curve of the four cranks. The loading of the pistons may be effected by springs or hydraulic pressure. Reciprocating inertia masses may be used instead of pistons. The ratio of the speed of drive of the auxiliary shaft driving these masses to the speed of the main shaft must be equal to half the order of the harmonic component to be opposed.