This paper is an investigation to determine flow coefficients of small round orifices of the sizes used with diesel engines. The values of the flow coefficients were obtained under injection pressures, under back pressures, and at oil temperatures of the area before the orifices.
The results of this experiment showed that
(1) The oil temperatures of the area before the orifices from 16°C to 51°C had no effect on the values of the flow coefficients.
(2) The values of the flow coefficients were constant, independent of Reynolds numbers, under the back pressure 0 atg and under the injection pressures from 94 atg to 460 atg, and were not closely connected with Reynolds numbers under the back pressures above 0 atg.
(3) The values of the flow coefficients, plotted against those of Euler numbers not those of Reynolds numbers, drawed a single curve.
(4) The values of the flow coefficients became lower with the higher values of Euler numbers, and, unchanged with the above 200 values of Euler numbers.
(5) The flow coefficients, C_t, were expressed by
C_t=k [0.705+0.829/ (1+E_t) ^1.03]
where k=exp [-2.76 (log d_t+0.405) ²-4.84 (logλ+0.521) ²- (l_t/d_t-3.36) ²×10^-2]
E_t=Euler number
λ=d_t/d_s
d_t=diameter of orifice, mm
l_t=length of orifice, mm
d_s=diameter of upstream section, mm.
(6) The most suitable size of small round orifice was
d_t = 0.394 mm, λ=0.301, and l_t/d_t=3.36.
These experimental data will be useful in measuring the values of injection rate by pressure-lift method and in designing injection nozzles.

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Engine control room in ship is totally kept optimum air temperature and humidity conditions by air conditioning unit.
Generally, exclusive packaged air conditioner is installed in engine control room.
The planning of air conditioning unit needs firstly decision of unit capacity. The capacity is decided by accumulation of each cooled or heated load in engine control room, in general.
This paper shows abstract of instruction for design and outfitting of air conditioning unit, mainly capacity planning and outfit planning of unit.

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Over a very long period, Sulzer has further developed large Diesel engines step by step. While in earlier times the main target was an increased specific power, for the last decade the main efforts have been devoted to a reduction in the specific fuel consumption, in order to relieve the operators at least partly from the drastic increase in fuel price. A further step towards improved overall efficiency has been attained for low-speed engines by the introduction of the “superlong-stroke” design RTA, featuring a spectacularly low specific fuel consumption as well as optimally low propeller speed matching highly efficient propellers.
The development and design of the new engine series has been based on three major“pillars”, the immense service experience from predecessor two- and four-stroke generations, the full exploitation of the modern theoretical analysis means, as well as a comprehensive experimental programme with reduced-scale models, full size components and a four-cylinder test engine.
The first RTA-series engine began its trials for confirmation tests and final optimization in Japan at the end of 1982. The results obtained so far fully confirm the high thermal efficiency as well as the high safety level of all components. Sulzer is convinced that the RTA series will become another successful member of its well-reputated low-speed engine family, ensuring good reliability and high overall economy to their owners.

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