Pme (BMEP: Brake mean effective pressure)
Although the 17.0 bar had been used in many vessels, the 18.2 bar, which is used as a rate (Rl rating) of RTA96C, had not actually been tested in a vessel as yet.
From a technical viewpoint, the only improvement of using the 18.2 bar which has three fuel valves instead of two fuel valves per cylinder is to maintain an equal thermal distribution in the combustion chamber of the RTA96C. From our standpoint, it was difficult to determine what amount of improvement made a tangible difference. Finally, NYK decided upon a 0.5 bar increase limitation which resulted in specifications of 17.5 bar or less.
Cm (Mean piston speed)
Though there had been several trials using new types of piston rings, actual vessel results still had not been confirmed. Based on this fact, we decided that 8.33 m/s (which is used as a rate (R1 rating) of RTA96C) would be slightly too risky, and chose the more conventional value of 8.0 m/s or less. (Please refer to Figure 4).
Risk of first engine
The developing process was framed around the following steps:
a) Design
b) Simulation and experiments on test bed to the check design
