Diesel generator set accessories introduction - fuel injection pump

Diesel engines are assembled from many important components, mainly composed of the body, two major mechanisms (crank connecting rod mechanism, valve train), and four major systems (fuel supply system, lubrication system, cooling system, and starting system). In this article, the generator manufacturer JUNVOCH introduces you to the fuel injection pump, an important component of the fuel supply system.

 

1. The role of the fuel injection pump of the diesel generator set

1.1  Increase the oil pressure (constant pressure): increase the injection pressure to 10MPa ~ 20MPa.

1.2 Control the injection time (timing): inject and stop the injection according to the specified time.

1.3 Controlling the amount of fuel injection (quantitative): According to the working conditions of the diesel engine, change the amount of fuel injection to adjust the speed and power of the diesel engine.

 

2. Requirements of diesel generator set for fuel injection pump

2.1 The oil is supplied according to the working order of the diesel engine, and the oil supply of each cylinder is uniform.

2.2 The fuel supply advance angle of each cylinder should be the same.

2.3 The oil supply duration of each cylinder should be equal.

2.4  The build-up of oil pressure and the stop of oil supply must be rapid to prevent dripping.

 

3. Classification of fuel injection pumps for diesel generator sets

3.1 Plunger fuel injection pump.

3.2 Pump-injector type, which combines the fuel injection pump and the fuel injector.

3.3 Rotor-distributed fuel injection pump.

 

4. The structure of a typical diesel generator set fuel injection pump

The commonly used diesel fuel injection pumps in my country are: A-type pump, B-type pump, P-type pump, VE-type pump, etc. The first three are plunger pumps; VE pumps are distributed rotor pumps.

 

(1) Structural characteristics of B-type fuel injection pump

1. Adopt spiral groove plunger and flat hole plunger sleeve;

2. The oil volume adjustment mechanism is a gear rod type, and an adjustable maximum oil volume rigid limiter (some use a spring limiter) is installed at the front end of the gear rod;

3. Adjusting screw type roller body transmission parts;

4. The camshaft is a tangential cam and is supported on the housing with tapered roller bearings.

5. The pump body is integral and adopts independent lubrication.

 

(2) Structural characteristics of P-type fuel injection pump

1. Suspended wheel pump assembly The plunger, plunger sleeve, oil outlet valve and other parts are fixed together with a wheel pump steel sleeve with a flanged plate to become an assembly part. It is directly fixed on the shell with gold studs to form a suspended structure. The sleeve can be rotated by a certain angle.

2. Adjustment of the oil supply of each sub-pump There are arc grooves on the flange plate of the steel sleeve of the sub-pump, loosen the compression stud, and turn the steel sleeve, the plunger sleeve of the sub-pump will rotate with it to a certain angle, changing When the position of the oil inlet and return holes is relative to the upper chute of the plunger, the oil return time will change.

3. The adjustment of the oil supply starting point of the sub-pump increases or decreases the gasket under the flange plate sleeve, so that the oil inlet and return holes of the plunger sleeve move up and down a small amount, thereby changing the position relative to the upper end of the plunger. Start of fuel supply.

4. The ball-pin angle plate type oil volume adjustment mechanism is welded with 1~2 steel balls on the end face of the transmission sleeve. The cross section of the oil supply rod is in the shape of an angle steel, and there is a small square notch on the horizontal right-angle side. Engage with the steel ball on the drive sleeve. Non-adjustable roller body transmission parts;

5. The fully enclosed box type pump body adopts the integral type sealed pump body without opening the side window, only the upper cover and the lower cover. The pump body has high rigidity and can withstand high fuel injection pressure without deformation, so that the life of the plunger pair is longer;

6. Pressure type lubrication is adopted;

7. There is a special preparatory stroke inspection hole. There is a screw plug above the roller body. This hole can be used to check whether the preparatory stroke of each sub-pump is consistent (measured with a special instrument).