15-11-2017, 11:34 AM
Energy research on methanol-fueled car engines has been transmitted from the standpoints of low environmental pollution and the use of alternative fuel since the oil crisis, and are now being tested on vehicles in several countries around the world. Several technical problems have already arisen. solved or the perspective is bright for them. It can be said that this type of engine is very close to being completed today. On the other hand, it is a real situation in the field of the marine engine that research on this type of engine has barely been proven so far, since it has rarely been evaluated from the point of view of the control of environmental pollution because it is used at sea and the idea of using methanol in marine engines is not yet established.
However, the IMO (International Maritime Organization) is investigating to include the exhaust gas of ships in the objects that will be controlled from the point of view of the protection of the environment on a global scale that has been highlighted aloud recently. In case clean methanol is used as fuel, work can be avoided to handle complicated machines such as centrifuges for heavy fuel and to treat the mud discharged from them, and in addition it can be expected that the frequent maintenance work of the engine will be reduced.
Therefore, it has been strongly desired to use methanol in marine diesel engines from, mainly, the point of view of the search for the economy. Although the knowledge that has been obtained with automobile engines can be used in principle, many issues remain to be solved, since marine diesel engines have large holes and average effective pressures of more than two times, their operating conditions are extremely severe and need high reliability and durability compared to automobile engines.
Methanol has a cetane number of three and, therefore, extremely low flammability. Marine engines with spark ignition can not present average effective pressures as high as those of ordinary diesel engines due to the high rate of pressure increase during ignition and can not allow a misfire due to the large volume of their systems. escape. The dual fuel injection system that has actual service results in large gas engines has been selected as the ignition system for this investigation.
A single-cylinder, four-stroke direct injection diesel engine with an internal cylinder diameter of 250 mm was modified to be suitable for this experiment. The rated speed of this experimental engine has been set lower than the original type so that the results of this research can be used as widely as possible.
The combustion system of the experimental engine is a dual fuel injection type, so that the main fuel injection valve (methanol) is located in the center of the combustion chamber and the atomized fuel of this valve is ignited by the pilot oil injection of the secondary injection valve (oil) located in the cylinder head near the periphery of the combustion space.
This system has been adopted for the reasons that has the high stability of ignition, good performance of low load and high reliability, and that serves as a measure to prevent corrosion, since the combustion tanks made by pilot oil injection cover the internal surface of the combustion chamber. The methanol injection pump is a forced lubrication type to avoid lubrication problems.
Because methanol is highly volatile, the auxiliary equipment of the methanol system such as the fuel tank, the filter, the supply pump and the valves have been installed in a closed chamber (a fuel supply unit) as shown in Fig.2 A fan and a gas detector were installed to sufficiently ventilate the interior of the unit for safety. Pipe joints also have a special structure to prevent fuel leaks.
However, the IMO (International Maritime Organization) is investigating to include the exhaust gas of ships in the objects that will be controlled from the point of view of the protection of the environment on a global scale that has been highlighted aloud recently. In case clean methanol is used as fuel, work can be avoided to handle complicated machines such as centrifuges for heavy fuel and to treat the mud discharged from them, and in addition it can be expected that the frequent maintenance work of the engine will be reduced.
Therefore, it has been strongly desired to use methanol in marine diesel engines from, mainly, the point of view of the search for the economy. Although the knowledge that has been obtained with automobile engines can be used in principle, many issues remain to be solved, since marine diesel engines have large holes and average effective pressures of more than two times, their operating conditions are extremely severe and need high reliability and durability compared to automobile engines.
Methanol has a cetane number of three and, therefore, extremely low flammability. Marine engines with spark ignition can not present average effective pressures as high as those of ordinary diesel engines due to the high rate of pressure increase during ignition and can not allow a misfire due to the large volume of their systems. escape. The dual fuel injection system that has actual service results in large gas engines has been selected as the ignition system for this investigation.
A single-cylinder, four-stroke direct injection diesel engine with an internal cylinder diameter of 250 mm was modified to be suitable for this experiment. The rated speed of this experimental engine has been set lower than the original type so that the results of this research can be used as widely as possible.
The combustion system of the experimental engine is a dual fuel injection type, so that the main fuel injection valve (methanol) is located in the center of the combustion chamber and the atomized fuel of this valve is ignited by the pilot oil injection of the secondary injection valve (oil) located in the cylinder head near the periphery of the combustion space.
This system has been adopted for the reasons that has the high stability of ignition, good performance of low load and high reliability, and that serves as a measure to prevent corrosion, since the combustion tanks made by pilot oil injection cover the internal surface of the combustion chamber. The methanol injection pump is a forced lubrication type to avoid lubrication problems.
Because methanol is highly volatile, the auxiliary equipment of the methanol system such as the fuel tank, the filter, the supply pump and the valves have been installed in a closed chamber (a fuel supply unit) as shown in Fig.2 A fan and a gas detector were installed to sufficiently ventilate the interior of the unit for safety. Pipe joints also have a special structure to prevent fuel leaks.