Causes of failure of engine speed of 2.0 ton excavator

Causes of failure of engine speed of 2.0 ton excavator

2020-12-09 11:15:24  edit:xiaoli

20. How to deal with the engine speed failure of excavator, let's find out today.

Causes of failure of engine speed of 2.0 ton excavator

One of the most common problems with excavators is that the engine is out of control. At present, the maintenance speed of 20 excavators is getting faster and faster, which may cause serious accidents such as damage to cylinders and diesel engines.

1. Diesel engines usually only occur when the load suddenly starts or disappears or releases, and the vehicle speed does not occur. There is no speed failure under load. Let's analyze the out-of-control speed of 20 excavators.

Inertial oil bath air filter oil contains too much oil. It is sucked into the cylinder and burned. It is equivalent to increasing the fuel supply, but also accelerating to cause speed.

2. Due to installation deviation or oil blockage, the plunger of the fuel injection pump will rotate and lose the speed control bracket. Especially the multi-cylinder oil pump will have a load rejection situation, and the oil supply will not change to cause this situation.

3. The single-cylinder diesel engine single-pulse pump governor drive sleeve is stuck, causing malfunction and speed control failure.

4. Some oil inlet holes and oil return holes on the plunger sleeve of the fuel injection pump are in the same plane position. If the positioning screw of the plunger sleeve is too long to block the oil return hole, the oil return will not be smooth, resulting in insufficient oil supply. The surge will also lead to acceleration.

5. The fuel pump adjusts the gear to the fuel supply position, or the rack and the governor lever are separated and out of control.

6. If there is too much oil in the governor housing, the speed will not turn on, which will affect the speed adjustment. The friction clutch of the governor will slip, the high-speed limit screw and safety device of the governor will loosen, withdraw quickly or get stuck, the governor spring will break, the thrust bearing or governor bearing will be damaged, resulting in the governor speed malfunction.

If the vehicle accelerates, the diesel engine may have serious consequences if it does not stop immediately. Therefore, when acceleration occurs, a way must be found to stop the diesel engine immediately. Emergency measures include the following:

1. Block the intake pipe, then the diesel engine will not turn into air and stall.

2. Heavy load can be used when driving, which means that the brake will reduce the engine speed and then turn off.

3. Place the throttle handle in the position where no fuel is required, open the pressure reducing device, and extinguish the cylinder without pressure.

4. Use a wrench to loosen the nut of the high-pressure oil pipe joint so that the diesel engine can be shut down without oil supply.

20 Why can't the excavator refuel?

(1) Check whether the oil circuit is blocked. First remove the oil pipe, remove the arm-type slide valve body, clean the valve stem and related parts, clean the oil circuit, and blow dry with compressed air. From the perspective of surface phenomena, it is mainly caused by seal failure, damage, squeeze or the sealing surface being pulled. Check whether the cone valve of the entire safety valve is stuck; check the fit clearance between the valve stem and the valve body. The normal fit clearance should be between 0.005 and 0.025 mm, and the maintenance limit should be 0.04 mm. Check the gap of the main valve core on the main valve sleeve. The standard clearance for normal fit is 0.010~0.018mm, and the repair limit is 0.03 mm.

(2) Grind the two-speed valve to remove burrs, so that the valve core can move freely in the valve body without jamming. First, check the slow moving side. Starting from the combination valve, remove the two oil pipes on the pressure limiting valve and insert them into the oil ports. The central rotary joint has many oil passages that are easy to collude with each other.

This is the problem of the engine speed of the excavator and the reason why the throttle cannot be increased. Hope it helps you.

Copyrigh: MINI Excavators&Crawler Hydraulic Excavator