1 Lubrication system A function; is to transport the oil to the lubrication surface as required, so that the oil film on each surface reduces friction and makes the engine run normally. At the same time, it can also cool, clean, seal, anti-corrosion and shock absorption.
B lubrication parts
Oil pump, oil cooler, oil filter, oil pipe, oil pressure regulator, pressure limiting valve.
C lubrication form; pressure lubrication and splash lubrication combined. The large bore low speed high speed diesel engine is pressure lubricated. Modern diesel engine oil should take 1.5-3% of the total heat of the fuel, and use engine oil to cool the piston's engine 45-55L/KW.h. The high oil temperature can make the internal combustion engine have high mechanical efficiency, but the oil temperature is too high. The viscosity of the oil can not be guaranteed. The thickness of the oil film between the friction pairs is increased, and the oxidative deterioration speed of the oil is accelerated until the shaft is burned.
2 cooling system function; using external soft water through the engine water pump, forced into the cooling water chamber, reduce the internal temperature, so that the engine is running normally.
A parts; pump casing, pump shaft, impeller, gasket, radiator, water pipe, etc.
B cooling form; forced cooling, the coolant does not directly communicate with the external atmospheric pressure, the pressure in the system is higher than atmospheric pressure, so the outlet temperature of the coolant can be increased, which is beneficial for improving the thermal efficiency of the internal combustion engine.
2 surface evaporative cooling; it uses the water in the evaporating water tank for heat dissipation,
3 circulation heat; this cooling method is to take the outside water into the internal combustion engine and then discharge it to the outside world. Circulating cooling is used for small vessels.
3 fuel supply system
1 function; when the diesel engine is working, the oil pump extracts the diesel oil from the diesel tank, passes through the diesel filter, and sends it to the fuel injection pump. The fuel injection pump increases the diesel pressure and periodically delivers the high pressure oil pipe to each injector and fog. Combustion.
2 parts include: diesel tank, oil pipe, oil pump, diesel filter, oil pipe, fuel injection pump, high pressure oil pipe, fuel injector, etc.
3 technical requirements; the oil pump should have sufficient flow to supply the fuel injection pump, and the circulating oil supply of the fuel injection pump should reach the power requirement of the oil machine.
4 requirements for diesel quality
Diesel is directly evaporated from petroleum at temperatures ranging from 200 to 350 °C. Diesel is divided into light diesel and heavy diesel. Light diesel is used for diesel engines above 1000r/min, and heavy diesel is used for diesel engines below 1000r/min. Diesel grades +10,0,-10,-20,-35,-50. Indicates liquidity.
A good ignitability; the diesel engine is made by the diesel fuel injected into the cylinder and the compressed high-temperature air to find the fire on its own, and it is difficult to find fire when it is fired. It is an important indicator of the nature of diesel.
B Appropriate evaporability; refers to the ability of an object to be converted from a liquid to a gaseous state. According to the evaporative use process, the process refers to a temperature range in which the liquid fuel changes from a liquid state. When the temperature is 50%, the temperature should not be higher than 300 ° C, and when the temperature is 90%, the temperature should not be higher than 350 ° C. For diesel engines, the mixing time is very short, about 3‰-4‰ seconds, and the diesel oil needs better evaporation, so that it can evaporate quickly to form a mixture. This shortens the ignition delay period, but the evaporation is too good for the diesel engine. The diesel fuel injected into the cylinder during the fire delay period will form excessive vapor. When the flame appears, almost all of the injected diesel fuel will participate in the combustion, and the image of rough work will appear.
C appropriate twist; is an indicator of the thickness of the fluid and the ease of flow. Excessive fluidity is poor, affecting the oil supply, and the fuel consumption rate is increased. If the enthalpy is too small, when the injection is small, the oil particles are small and the range is too short, and the same cannot be distributed in the entire combustion chamber to mix with the air. As a result, the combustion is incomplete and the wear of the fuel injection parts is increased.
D. The lower freezing point of the diesel oil increases with the temperature drop, and loses its fluidity when it drops to a certain temperature.
E does not contain mechanical impurities and moisture; there should be no mechanical impurities in diesel fuel, because mechanical impurities will accelerate the wear of the precision parts of the fuel injection injector, reducing their matching accuracy may also block the oil circuit and the nozzle hole affecting the normal operation of the diesel engine. jobs. If the diesel contains water, it will make the diesel engine unstable, and it may freeze at low temperatures and block the oil circuit. If it is not possible to say that there is no water, only the water content is allowed to be below 0.025%.
4 starting system [including electric start and air start]
1 electric start; internal combustion engine does not start by itself, must rely on external force, the first combustion will occur, motor [starter] is widely used in vehicle start and fixed diesel engine start. There are mainly starters, relays, and external power supplies.
2 requirements; the starting torque must be greater than 5-10% of the starting torque of the diesel engine.
5 intake and exhaust system
1 intake system; including air filter, intercooler, compressor, intake pipe, etc.
2 requirements; the entry is fresh air, the intake pressure is higher than the atmospheric pressure, the intake pipe is smooth and smooth, the curve is as small as possible, the area should be as large as possible, and the seal should be better.
3 exhaust system; including exhaust pipe, volute, exhaust pipe, silencer and so on.
4 requirements; the general requirement is that the exhaust pipe should be unblocked, the pressure should be small, and the exhaust gas should be clean.