The engine of the excavator is powerless and emits white smoke. It can't be filled with oil. It's the source of the engine's suffocation and flameout
Nowadays, the assembly of EFI engine is the trend of the times. No matter how much we like and miss the solid, durable and low failure rate direct injection engine, we can't go back to the past. Like history, the wheels roll forward
But now the popularity of EFI is inevitable. Since we can't change history, we can only adapt to the development of the times. Therefore, we must have more understanding of EFI technology, pursue advantages and avoid disadvantages, and minimize the disadvantages and risks of EFI
Features of excavator EFI engine
Today we will start with the first characteristic of EFI engine
The first feature of electronic injection engine is to change the fuel high-pressure system into electronic control injection, from the high-pressure pump to the common rail oil tank, and then to the electric nozzle
In short, there are many wires, harnesses and sensors on the engine Through these harnesses and sensors and the sorting, analysis and command of ECU (ECM), the injection system can be controlled accurately in many aspects such as pressure, temperature and injection volume, so as to achieve the goal of environmental protection and energy conservation
Nozzle structure
After understanding the basic structure of the fuel injection nozzle, we will analyze the main fault points, fault causes, fault phenomena, judgment methods and precautions
Fault point of fuel injection nozzle
1. Control piston, failure rate 40%
2. Nozzle needle valve, failure rate 40%
3. Electronic coil and two-way valve, failure rate 10%
4. Failure rate of other accessories: 10%
It can be seen that most of the fault points of the electric nozzle are on the control valve and nozzle needle valve
Fault cause:
1. The liquid containing water or other chemical components in the fuel will lead to corrosion, rust death of the control piston and nozzle needle valve and sintering due to insufficient lubrication, which will lead to failure in fuel injection or accurate control of the amount and direction of fuel injection, affecting the atomization effect and mixture concentration. 65%
2. The fuel contains other solid particulate impurities, which cause the control piston and nozzle needle valve to be worn, scratched and stuck, resulting in failure to inject fuel or to accurately control the amount and direction of injection, affecting the atomization effect and mixture concentration, accounting for 30%
3. Other reasons: such as poor manufacturing and process of accessories, short circuit and open circuit of wires, accounting for 5%
Fault phenomenon
When the electric nozzle fails, the excavator engine fails
1. The power of the whole vehicle is insufficient, and the engine makes a sudden noise of lacking cylinders
2. According to the stuck position of the nozzle, if the atomization is not good, the engine may emit white smoke
3. If more than one nozzle fails, the engine will have unstable idle speed, or it will not be able to add oil, and in serious cases, it will hold back and shut down
Judge the fault mode
1. In the cylinder cutout experiment, observe the engine speed drop after cylinder cutout. The most serious drop is the faulty nozzle
2. Use a thermometer to detect the temperature of four or six cylinders. The cylinder with low temperature is the cylinder where the faulty nozzle is located
3. Remove all nozzles, and use batteries and pressure gauges to detect the opening spray pressure and atomization of nozzles
How to reduce the occurrence of faults?
Most of the nozzle failures are caused by fuel quality. Therefore, in order to reduce the nozzle failure rate, the following points should be noted:
1. When refueling, pay attention to the hygiene of fuel and refueling environment to avoid sandstorm. You can also filter impurities by adding silk socks and other methods
2. Don't add black oil from unscrupulous merchants. Don't add oil at the bottom of the refueling truck. It's best to add clean oil to your oil bucket after it has settled for 12 hours
3. Diesel oil, aviation kerosene and other heavy oil and light oil must be distinguished. Insufficient lubrication will wear and even sinter the plunger and valve needle
4. Before construction every day, the impurities and water precipitated from the bottom of the oil tank and the oil-water separator must be discharged first
5. If there is a fault, do not discard the fuel injector that has been repaired and replaced, because the accessories inside can be assembled and used again
summary
In short, the EFI nozzle is both delicate and delicate. Once it is not taken care of, it will immediately break down and lead to shutdown. Therefore, we need to take care of it carefully while improving our attention!
