The authors systematically conducted experiments for determining the present levels of NOx emission from small-size, high-speed to medium-size, medium-speed diesel engines. The effects of various factors on NOx emission were investigated through experiments and simulating calculations on the engines to find the factors that lower NOx levels. As a result, it has been found that the reduction in NOx without degrading the specific fuel consumption not so much can be achieved by injection timing retarding and properly increasing the compression ratio and air boost pressure to maintain the Pmax, which decreased by timing retarding, of the design point. Furthermore, it has been found that the influences of ambient conditions such as ambient temperature, humidity and intake air temperature have to be taken into account for evaluating NOx. And nitrogen content in fuel is also needed to take into account.
It is important for the energy saving to evaluate the performance of the marine propulsion plant in operation. The object of this study is the diesel propulsion system rated at 1, 103kW, installed in a training ship “Fukae-maru” (449 Gross Tonnage) owned by Kobe University of Mercantile Marine. Experiments have been made under the various loads of this engine on calm sea. In the analysis, the entire plant is assumed to be a steady-flow system, and both the first-and the second-law of thermodynamics are employed in order to clarify not only the quantity of energy but also the quality of energy. In consequence of these analyses, the places where the energy losses are generated in this plant are made known, and the Sankey diagrams (energy-flow diagrams) and the exergy efficiencies of this plant are also obtained.
Following the 1st. report of the main diesel engine system, the results of the performance evaluation of the emergency electric propulsion system on“Fukae-maru”are descibed in this paper. This system consists of the 200kW differential drive shaft generator-motor, the hydraulic system to drive the armature, and their attachments. Experiments have been made varing propeller pich angle and varing the direction of armature rotation on calm sea. In the analysis, the entire plant is assumed to be a steady-flow system, and both the first-and the second-law of thermodynamics are employed in order to clarify not only the quantity of energy but also the quality of energy. In consequence of these analyses, it becomes clear that the method of this analysis is effective to evaluate the performance of the plant which has the several forms of energy like in this plant. And, the Sankey diagrams (energy-flow diagrams) and the exergy efficiencies of this plant are also obtained.
For a high speed diesel engine, gas oil and Marine diesel oil (MDF) are used in general, but, on account of the utilization of alternative energy, and in order to decrease particulates and nitrogen oxides (Nox) in exhaust gas, blending alcohol with petro-fuels has been studied widely in many institutes. Here, separation rate of blended fuels of ethanol and gas oil or LCO (Light Cycle Oil) was measured in order to study the stability of these blended fuels fundamentally. In general LCO has not good industrial usage because it's cetane number is not high enough to be used in a diesel engine recently, but in this paper, it is found that LCO blending has shown astrong effect of improving the solubility of ethanol into gas oil. So, this finding will give a new industrial usage to LCO.
For the chemical tanker, cargo residues of substances with a vapour pressure greater than 5×103 Pa at 20°C may be removed from a cargo tank by ventilation. But according to the prevention of marine pollution (MARPOL73/78), the ones with a vapour pressure less than 5×103 Pa at 20°C must not be removed by ventilation. Recently stripping systems are developed, and on some chemical tankers the stripping residues quantity is decreased less than one litre by using thin pipe. If chemical substances with the little vapour pressure are removed by ventilation, this procedure is very useful for the operation and the prevetion for sea pollution. Hence the posibility of the removal by ventilation was examined by the model tank test and on board test. The experimental results show that the residues in the tank well is removed by ventilation using the suction pipe or stripping pipe. And the liquid adhering to the wall can be also removed by the ventilation.