Rg, 7 15 TOURS 66 diesel engine layout. 



exhaust gas line to outboard. The diesel en- 

 gine is equipped with decompression equip- 

 ment and complies with the regulations of 

 Germanischer Lloyds. 



The engine is cooled through a seawater- 

 freshwater twin circulation system incorpo- 

 rating both seawater and freshwater pumps. 

 The diesel fuel tank is within the exostruc- 

 ture. The fuel (0.47 m^) is delivered by means 

 of the fuel pump attached to the diesel en- 

 gine through a fuel tapping dome. Compen- 

 sation for used diesel fuel is effected by 

 means of the vehicle's trim tanks. A surface 

 cruising range of 400 nautical miles at 5 

 knots is possible. The diesel engine drives a 

 DC shunt-wound generator, which is self- 

 ventilated, and supplies 15 kW of charging 

 power for the main battery at 3,000 rpm, 

 with a voltage range between 250 and 290 

 and a maximum charging current of about 60 

 amp. Central ventilation is provided for the 

 battery room. The air is sucked by the bat- 

 tery-room fan from forward to aft over the 

 cells. During surface operation the air is 

 passed to outside via the exhaust air mast. 



The present use of diesel engines in sub- 

 mersibles (only in surface operations) avoids 



a great number of the problems that would 

 be encountered in closed-cycle diesel power 

 systems supplying submerged power (see 

 refs. 5 and 26). Nonetheless, Sub Sea Oil 

 Services of Milan is presently conducting a 

 research and development program which it 

 hopes will result in a system capable of both 

 extended surface cruising and closed-cycle 

 underwater operation for PHOENIX 66. 



The results of a program at Aerojet-Gen- 

 eral, Azusa, California, in 1970 have direct 

 application to closed-cycle diesel power sys- 

 tems and warrant the attention of present 

 and future submersible power design engi- 

 neers. Commencing as an in-house research 

 and development program, the Aerojet 

 power system called "Psychrodiesel" re- 

 ceived additional funds from the U.S. Air 

 Force to develop a breadboard model and 

 conduct demonstrations of a prototype 

 closed-circuit power system. 



Psychrodiesel operates on a principle Aero- 

 jet called "Psychrocycle," in which the diesel 

 engine "breathes" a mixture of oxygen gas 

 and water vapor in place of air. This syn- 

 thetic air combusts with diesel fuel to pro- 

 vide an exhaust consisting only of water 

 vapor, carbon dioxide and unconsumed oxy- 

 gen. The steam (water vapor) is condensed, 

 the carbon dioxide chemically absorbed and 

 the oxygen recycled to complete an operating 

 closed cycle. Thus, the complete system is 

 fully enclosed during an undersea operation. 



In a detailed discussion of the history, 

 development, and operation of the Psychro- 

 diesel, Hoffman et al. (30) compare its effi- 

 ciency with other closed-cycle systems, e.g., 

 Rankine, Stirling, and Brayton, and specu- 

 late that the internal combustion engine 

 may achieve higher thermal efficiency than 

 the Stirling because its maximum cycle tem- 

 perature is nearly double. Of particular in- 

 terest is their design of a Psychrodiesel sys- 

 tem (both closed-cycle and air breathing) for 

 small and large submersibles which could 

 supply power for propulsion and hotel loads. 

 The small submersible Psychrodiesel pack- 

 age is 4 feet in diameter by 6 feet in length 

 and delivers 60 kWh submerged. The large 

 system configuration constitutes a module 4 

 feet in diameter by 20 feet in length, totaling 

 16,000 pounds and delivering 1,000 kWh sub- 



337 



