1. Injector common faults and effects

(1) Poor spray injection
When the injection pressure is too low, the spring end face is worn or the spring force is decreased, the injector will be opened early, the time will be closed, and the injection atomization will be bad, resulting in the diesel engine power falling, the combustion is insufficient, and the exhaust pipe is exhausted. Black smoke.
(2) Seal failure, white smoke and accompanied by cannon
When the injector is working, the sealing cone surface of the needle valve body is subjected to the frequent strong impact of the needle valve and the abrasive wear, the taper surface will gradually appear scratches or pitting, and the contact width of the taper surface increases, thereby causing the seal failure and the fuel injection. Drip oil. When the diesel engine temperature is low, the exhaust pipe emits white smoke; when the diesel engine temperature is high, the exhaust pipe emits gunfire from time to time in addition to black smoke. At this time, if the supply of oil to the cylinder is stopped, the smoke and the sound of the cannon quickly disappear.
(3) The needle valve is stuck and cannot be sprayed
If the moisture or acid in the diesel oil is excessive, the needle valve will be stuck due to corrosion; when the sealing cone of the needle valve is damaged, the combustible mixture in the cylinder will also break into the mating surface and form carbon deposit, so that the needle valve is If it is stuck, the injector cannot spray oil, causing the cylinder to stop working.
(4) Internal leakage, long injection time, difficulty in starting
When the needle valve makes frequent reciprocating motion in the needle valve hole, if the diameter of the impurity particles in the diesel oil is too large, the needle valve hole guiding surface will gradually wear, resulting in increased injector leakage, pressure drop and fuel injection time. It causes difficulty in starting the diesel engine and increases vibration during operation.
(5) The combination hole of the injector and the cylinder head leaks and simmers
If the injector has carbon deposits in the mounting holes on the cylinder head, the copper washers are not intact and uneven. The asbestos board or other material is used instead of the copper material, or the thickness of the gasket cannot ensure that the injector extends out of the cylinder head plane. The heat is not good or the sealing effect is not caused, resulting in air leakage and oil leakage at the joint hole of the injector and the cylinder head.
(6) Black smoke
Due to the continuous jet scouring of the high-pressure diesel oil, the nozzle nozzle hole will be enlarged due to the gradual wear, resulting in a decrease in the injection pressure, a shorter injection distance, and an uneven mixing of the combustible mixture, thereby causing the black smoke phenomenon in the diesel engine. Charcoal will also increase.

2. Insulin maintenance and maintenance points

(1) Improve the installation position of the injector pad
Since the metal is most likely to wear when working under high temperature conditions, the injectors of the pin and hole injectors protrude into the combustion chamber, and most of the surfaces are in direct contact with the gas, and are subjected to high temperature and high pressure gas baking. It is the main cause of the wear of the injector needle cone and the needle guide surface. For the pin needle injector, in order to avoid the whole nozzle of the injector being gas-fired, a suitable thickness of copper washer can be added to the nozzle head; for the hole injector, a v-shaped pad can be added, v The pad should be designed so that the outer diameter is as large as possible, so that the inner hole is as large as possible, so that it can be disassembled and prevented from invading when the injector is replaced.
(2) Regularly check and adjust the injector
The injector should be checked and adjusted once every 700 hours of operation. If the opening pressure is lower than the specified value, the needle valve should be unloaded, put into the clean diesel oil, scrape the carbon deposit with wood chips or copper sheets, use the fine iron wire to clear the spray hole, and then debug after repairing. It is required that the injection pressure difference of each cylinder on the same diesel engine must be less than l MPao
(3) Regularly check and adjust the fuel injection advance angle of the fuel injection pump
In order to make the fuel injected into the cylinder of the injector can be mixed uniformly and completely burned, it is necessary to regularly check and adjust the advance angle of the fuel supply of the fuel injection pump. If the oil supply time is too early, the diesel engine will be difficult to start, and there will be faults such as knocking on the cylinder and increasing vibration. If the oil supply time is too late, it will lead to adverse effects such as black smoke, high engine temperature and rising fuel consumption. 

(4) Change the oil according to the season, regularly maintain the diesel filter
Due to the high precision of the needle valve coupler and the small orifice diameter of the injector, it is necessary to select the clean diesel oil of the specified grade in strict accordance with the seasonal changes, and regularly maintain the diesel filter, often drain the filter and The oil in the tank is used to prevent the intrusion of dust and impurities and accelerate the wear of the needle valve coupler.
(5) Carefully clean and replace the needle valve
When replacing the needle valve coupler, the needle valve member should be placed in hot oil of 70-80 °C for 10 minutes. Then, in the 'clean diesel oil, the needle valve is twitched back and forth in the valve body for thorough cleaning. In this way, it is possible to effectively avoid the failure of the needle valve to stick to the needle valve due to the melting of the rust preventive oil during operation. In addition, when cleaning the needle valve coupler, do not touch other hard objects to prevent the needle valve guide surface from being scratched.
(6) Avoid needle valve being stuck
When the high-pressure oil pipe joint is loosened, if a large amount of air bubbles or oil bubbles are seen, the needle valve is stuck in the open state, so that the compressed gas generated when the cylinder is compressed is poured into the high-pressure oil through the injector. At this time, if the high pressure oil pipe is touched by hand, the diesel pulsation or the pulsation is not felt. If the needle valve is stuck, due to the presence of particulate matter in the oil and residual iron in the injector, the injector may not work properly or may not work. At this time, the needle valve coupler should be cleaned and assembled again.
(7) Ensure that the diameter of the nozzle of the injector meets the technical requirements
If it is determined that the fuel injection pressure of the injector is not enough for the expansion of the nozzle hole, for a single-hole shaft needle injector, a steel ball with a diameter of 4 to 5 mm can be placed at the end of the hole, and lightly tapped with a small hammer to make The nozzle hole is locally deformed by plastic deformation to reduce the aperture; for the porous direct injection type injector, since the number of holes is large and the aperture is small, only an exclusive punch can be tapped at the end of the hole. If the technical requirements are still not met after the restoration, the needle valve coupler should be replaced.
(8) Avoid overloading the diesel engine for a long time
The diesel engine should avoid overloading for a long time to prevent the needle of the injector from being stuck due to overheating of the body. For long-term sealed diesel engines, the injector should be removed and immersed in clean diesel to prevent the needle valve from corroding and cannot be opened and closed flexibly.