Talking about the Causes of Difficulties in Starting Diesel Engines
Metallurgical Chemicals,Metallurgical Processing Chemical,Calcium Cyanamide Granule,Mining Metallurgical Chemical Ningxia Darong Chemicals & Metallurgy Co., Ltd. , https://www.darong-cyanamide.com
1 The smooth starting conditions of the diesel engine The diesel engine starts smoothly. The key lies in whether the diesel injected into the cylinder can quickly form a combustible mixture with the compressed air and ignite and burn. Whether it is mixture formation or combustion, the air entering the cylinder is required to be compressed to a higher temperature and pressure. From the point of view of the formation of the mixture, the higher the pressure of the air, the greater the density, the greater the resistance encountered when the diesel is injected, and the higher the quality of the diesel spray, the better the mixing with the air. At the same time, when the air temperature is high, the diesel easily evaporates, and quickly forms a good combustible mixture with the air. Diesel auto-ignition temperature is about 335C under normal pressure. For a combustible mixture, the ignition temperature decreases as the pressure of the combustible mixture increases. Therefore, after the air entering the cylinder is compressed, it has a higher temperature and pressure, which is the main factor for ensuring the smooth start of the diesel engine. In order to meet the above requirements, the following conditions must be met:
(1) Have enough speed. With high rotation speed and low gas leakage, the compressed air has a short heat transfer time to the cylinder and less heat loss, which can easily cause higher temperatures and pressures.
(2) The cylinder seal is good. It can reduce gas leakage and increase the pressure and temperature at the end of compression.
(3) The premise of fuel injection should meet the requirements, and the quality of the injection should be better, otherwise it will not form a combustible mixture.
Especially at low temperature start, the intake air temperature is low, and the start-up rotation speed is significantly reduced under low-temperature conditions, and the viscosity of the diesel oil increases and the atomization is unfavorable, thereby causing difficulty in starting the diesel engine.
2 Causes of Startup Difficulties Caused by Malfunction of Diesel Engine Supply System
(1) Injector valve stuck or plugged, injection pump column stuck, outlet valve sealed tightly, oil regulation lever failure, pump failure, related parts damage, etc. will make the injection pump will not produce high pressure oil fog.
(2) Fuel injection timing is not accurate. The reasons are the wear of the push rod roller and the cam, the damage of the fuel pump drive connected components and improper adjustment.
(3) low fuel injection pressure and poor atomization of fuel injection, multi-layered fuel injector needle stuck, fuel injector adjustment spring breakage and so on.
(4) The oil line is not supplied with oil. Most of the fuel tank is fuelless, the oil level is too low, the intake of the fuel pipe is damaged, the connectors are loose, the fuel is filled with water, the fuel filter and the overflow valve are blocked, and the filter is plugged.
3 Other causes of diesel engine startup difficulties
(1) The start-up speed is too low, the battery capacity is insufficient, the wire is loose and the contact is poor, the start-up power is weak, and the oil viscosity is generally increased to increase the resistance.
(2) The ignition temperature is too low (white smoke in the exhaust pipe), and hot water is not added to the water preheat cylinder block and cylinder head.
(3) Insufficient cylinder pressure. Cylinder liner ablation, cylinder head bolt looseness, cylinder leak, valve and valve seat ablation, etc.
(4) The electrical starting system is not working properly. The starter is damaged, and the gear teeth of the air ring gear are broken.
4 Startup Difficulties, Inspection Points
(1) Check the stock of diesel fuel and its quality, whether there is any blockage in the oil, and if necessary, clean and maintain.
(2) Check and tighten each oil fitting on the oil supply pump, and if necessary, discharge the air from the fuel.
(3) Maintain the filter. Clean as required, dry or replace the filter.
(4) After cleaning the nozzle assembly and installing it, it can be used after the pressure is qualified for debugging.
(5) Select high-quality lubricating oil and fuel according to different local seasons.
5 Relatively low temperature diesel start-up measures
(1) According to different temperatures, select the proper number of low-temperature diesel and diesel engine oil. Add antifreeze and anti-rust solution.
(2) Before starting, add about 80C of hot water (the vehicle without antifreeze).
(3) Shake the crankshaft several times to allow the oil to enter the mating surface so that all parts of the body are fully lubricated.
(4) Vehicles that have been cooled without antifreeze, especially under cold and cold conditions, should be placed with cold water while heating the water until the temperature of the body is appropriate.
(5) After using the car every day, the engine, the air reservoir, and the diesel prefilter should be drained.
(6) When the temperature is lower than 0C, the preheating screw can be rotated to the warm-up gear, and warmed up to 20-30C before starting.