Fig. 2.4.2-1 and Fig. 2.4.2.2 indicate the section and the performance of the S46MC-C type engine respectively. The second “C” of MC-C means Compact.
As shown in Table 2.4.2-1, the brake mean effective pressure of MC-C type engines was risen from 18bar to 19bar, and the mean- piston speed was also risen from 8.1m/s to 8.5m/s on the basis of the sufficient results of MC type engines. Consequently, the output was increased by 10%, while the engine speed was kept at the same as the current speed by increasing the stroke-bore ratio, S/D, from 3.8 to 4.0. Furthermore, S/D of the 6S46MC-C type engine was increased to 4.2 in aiming at the lower engine speed.
In spite of increasing S/D, however, the height of MC-C type engine was kept as same level as that of MC type engine by decreasing the connecting ratio from 2.29 to 2.05. By shortening the cylinder distance and by reducing the width of chain case, the overall length of the engine was reduced by 10%. Consequently, the weight of the engine was reduced by 10%.
