Caterpillar cat315 excavator, with a short arm bucket capacity of up to 4 cubic meters, has large power and high working efficiency. It adopts the mechanically actuated electronic control unit injector (EUI) fuel system. The EUI unit injector is used to generate high injection pressure by the mechanical force generated by the camshaft. This device combines the pumping element, electronic fuel metering element and fuel injection element in a separate device The electronic control system is designed into the engine fuel system and the engine intake and exhaust system as a whole to electronically control the fuel delivery and injection timing Compared with the conventional mechanical engine, the electronic control system can provide enhanced timing control and fuel air mixture ratio control Fuel injection timing is achieved by precise control of fuel injection ignition time The engine speed per minute is controlled by adjusting the duration of fuel injection
The computer board of Caterpillar cat315 excavator has the main control board of the locomotive. Because the handle is an electric control handle and the engine is an EFI engine, there are more input and output electrical signals than ordinary models. Therefore, the computer board has powerful functions. There are parameter keys on the monitor, which can call up many important parameters of the locomotive and engine, such as the output signal of the electric control handle and the current value of the pilot proportional solenoid valve on the main control valve that controls the action of each mechanism, The current of the power shift pressure reducing valve of the main pump and swing pump, the signals of various important sensors of the engine, etc
When the engine fails to start, the possible causes are the problem of the starting circuit, the failure of the fuel supply, or mechanical failure
Maintenance process:
Because it occurs under the condition of normal shutdown, the possibility of mechanical failure is very small. Turn on the key to turn on the power supply. If there is a circuit failure, the fault content and fault diagnostic code will be displayed in the information display center of the monitor. At this time, the low cooling liquid level will be displayed, because this display has already existed, which is a sensor failure and does not affect the startup. Press the main menu key of the monitor to adjust the line diagnostic fault and code, because there are no other fault displays, Don't consider the circuit reasons first During trial starting, the starting motor can rotate and the starting speed is enough, which can eliminate the possibility of problems in the starting circuit and insufficient battery voltage, and the engine sound is normal without abnormal noise Based on the principle of "easy first, difficult later", the possible causes of the oil circuit should be eliminated first, and the exhaust should be carried out first. There is no air in the oil circuit. When the hand pump pumps oil, the pressure is very high, and the fuel pressure is sufficient
The fault diagnosis code shows that the cooling liquid level is low at this time, because this display has already existed. It is a sensor fault and does not affect the startup. Press the main menu key of the monitor to call the line diagnosis fault and code. Because there are no other fault displays, the circuit reasons can be ignored first During trial starting, the starting motor can rotate and the starting speed is enough, which can eliminate the possibility of problems in the starting circuit and insufficient battery voltage, and the engine sound is normal without abnormal noise
First, eliminate the possible causes of the oil circuit. First, exhaust the air. There is no air in the oil circuit. When pumping oil by hand pump, you feel a lot of pressure, and the fuel pressure is sufficient. Check the fuel pressure regulating valve (back pressure valve), and there is no problem. There is no leakage or blockage in the oil circuit. The causes of the oil circuit can be preliminarily eliminated In order to further confirm that there is no fault in the circuit, it is necessary to check whether there is current to the electronically controlled unit injector. Because there is no special caterpillar Electronic Technician (ET) detection tool, the test lamp is used for detection. After detection, the test lamp is on, indicating that the circuit is normal and there is current to the injector. Therefore, it is preliminarily judged that the fault is the unit injector, because the injector of this machine has been used for more than 5000 hours, because the fuel quality on the construction site is very poor, The plunger, valve core, nozzle, etc. inside the electronic control unit injector have been worn, causing the fuel atomization and injection volume to fail to meet the technical standards, making the engine of Caterpillar cat315 excavator unable to start
When the left position of the reversing valve works, the pressure oil will enter the left chamber of the hydraulic cylinder from the left hydraulic control check valve. At the same time, the right hydraulic control check valve will be opened through the control port, so that the return oil in the right chamber of the hydraulic cylinder can flow back to the mailbox through the right hydraulic control check valve.
