Diesel oil piston rings
Oil piston rings are fitted first in grooves on piston crowns and in powerful slow-speed diesels (trunk piston type) additionally by two oil piston rings with thermal clearances at the junction with cuttings or drilled orifices along the perimeter for connecting and elimination of surplus oil to the diesel crankcase are installed.
The width of adhering to the cylinder liner surface belts of oil piston rings must be oriented of no more than 1 mm. For using the feeding pressure to take off oil film, the oil which is compound by lubricators and of oil circulation system, which is deposited on the cylinder liner surface during diesels running.
At the slow speed diesels cooling , as a rule, the piston crown with circulating oil by means of telescopic system with the temperature outing oil from the piston crowns according to the instruction on diesel maintenance as at the very high temperature the hydron and asphaltines falling from oil is going on, the clogging of piston cooling voids occurs – the heat transferring is delayed due to temperature drops and the cracks are formed on the piston crowns, the emergency situations occur and the diesel is out of order.
Internal combustion engine cooling
The diesel enclosed fresh water system. It is necessary to start with preparation of water. Fresh water must be soft (when necessary it is distilled – of high quality from the distilling plant with admixtures of anticorrosive mixture from the estimation of quality according to the instruction on diesel maintenance).
Cooling fresh water should be of anticorrosion property – protect the voids cooling of cylinder liners blocks, cylinder heads from corrosion and cavitating running, elimination of slag and salt depositing in the diesel cooling voids. There may be another grade of anticorrosive oils, which are dissolved in the fresh cooling water to the poor milky colour.
At the powerful slow speed diesels the difference of inlet (from the bottom of diesel block) and outlet cooling water (from cylinder heads) must be at the range of 5-7ºC.
The difference of temperatures at the close running cooling water cylinders should be not more than at 30ºC. With the aim of employing the flinging heat of cooling water when it is used in vacuum distilling plants (at the distilling plant warming up circuit), its temperature (cooling water) must be no less than 60ºC.
Gas turbo chargers, which deliver air to the scavenging header under the pressure of 3.5 p.eg.in. which the air temperature of 80ºC and more before the diesel scavenging header it is necessary to cool, according to the instruction on diesel maintenance (with fresh water or another way) for enlargement of weigh charge of delivery air for supplying into the diesel cylinders and providing burning a great deal of fuel – successive enlargement of diesel power and providing operative according to the cylinders, cooling fresh water temperature, exhaust gases, pressure and complete combustion of fuel in accordance with the norms of ecological requirements on environment protection (appendix 6 to the International Convention “MARPOL-73”).
Taking into account that the rotor of the gas turbocharger is an massive all-unit shaft made from alloyed steel of 120-300 kg in weight due to different constructive and powerful peculiarities of sliding bearing or ball bearings – they have autonomous lubricating system, which includes autonomous geared pump or another), autonomous capacity tank and cooler. The rotor shaft at the point of setting gas turbine by exhaust gases which induce rotor to be rotated, heats the rotary shaft of gas turbocharger up to 550º-700º, such temperature is badly dangerous for white metal both sliding bearings and ball bearings – the former is melted out and the latter is sticked, that’s why it is prohibited to switch off the autonomous gas turbocharger lubricating system after stopping of the main engine during 8-10 hours, as the white metal of sliding bearings is melted at the 450ºC.
The law of heat transferring in the metal heats the consoles of the rotary shaft at the same temperature as in the point of gas turbine setting.