High pressure fuel pump

Fuel pumps are designed to supply diesel cylinders to a cylinder at a certain pressure and at a certain point in the cycle, precisely measured portions of fuel corresponding to a given load applied to the crankshaft . According to the method of injection distinguish fuel pumps with direct action and battery injection .

In a direct-acting fuel pump, the plunger is mechanically driven, and the injection and injection processes occur simultaneously. In each cylinder section of the fuel pump delivers the necessary portion of fuel. The required spray pressure is created by the movement of the pump plunger.

In a fuel pump with battery injection, the working plunger is driven by the pressure forces of compressed gases in the engine cylinder or by means of special springs. On powerful low-speed diesel engines used battery fuel pumps with hydraulic accumulators .

In systems with hydraulic accumulators , the injection and injection processes proceed separately. Pre-fuel under high pressure is pumped into the battery, from which it flows to the injectors. This system provides high-quality spraying and mixing in a wide range of diesel loads, but due to the complexity of the structures, such a pump has not been widely adopted. Modern diesel engines use technology with control of solenoid valves from microprocessor devices (this combination is called “ common rail ”).

High pressure fuel pumps can be in-line, V-shaped (multisectional) and distribution. In the in-line injection pump, the pump sections are arranged one behind the other, and each supplies fuel to a specific engine cylinder. In distribution fuel injection pumps, which are single-plunger and double-plunger, one pump section supplies fuel to several engine cylinders.

Distribution pump injection unit:

1. reducing valve ;
2. all-mode regulator ;
3. drainage fitting ;
4. the housing of the high-pressure pumping section assembled with the plunger pair and discharge valves;
5. fuel pump ;
6. hatch control injection timing;
7. pump housing;
8. solenoid valve off fuel supply;
9. cam-roller device drive plunger.

The fuel supply from the tank to the injection pump is provided by the fuel priming pump (5), and the reducing valve (1) maintains a stable pressure at the inlet to the pump section of the injection pump, which is located in the housing (4).

The plunger pair of the pump section is a spool device that regulates the amount of fuel injected and distributes it to the cylinders of a diesel engine in accordance with the procedure for their operation . The all-mode regulator (2) ensures stable operation of the diesel engine in any mode set by the driver using the accelerator pedal and limits the maximum crankshaft speed , and the fuel injection timing regulator (6) changes the timing of the fuel supply to the cylinders depending on the engine speed.

Fuel pump feeds fuel to fuel pump in much larger volume than is required for diesel operation. Excess returns to the tank through the drainage fitting (3). As for the solenoid valve (8), it is designed to stop the diesel. When you turn the key in the ignition lock to the "off" position, the solenoid valve cuts off the fuel supply to the plunger pair, and therefore to the diesel cylinders, this is required to silence the power unit.

Depending on the pressure and duration of the injection, as well as on the magnitude of the cyclic fuel supply, there are the following models of in-line injection pumps:

• M (4-6 cylinders, injection pressure up to 550 bar)
• A (2-12 cylinders, injection pressure up to 950 bar)
• P3000 (4-12 cylinders, injection pressure up to 950 bar)
• P7100 (4-12 cylinders, injection pressure up to 1200 bar)
• P8000 (6-12 cylinders, injection pressure up to 1300 bar)
• P8500 (4-12 cylinders, injection pressure up to 1300 bar)
• R (4–12 cylinders, injection pressure up to 1150 bar)
• P10 (6-12 cylinders, injection pressure up to 1200 bar)
• ZW (M) (4–12 cylinders, injection pressure up to 950 bar)
• P9 (6-12 cylinders, injection pressure up to 1200 bar)
• CW (6-10 cylinders, injection pressure up to 1000 bar)
• H1000 (5-8 cylinders, injection pressure up to 1350 bar)

• Body
• Covers.
• All mode regulator
• Injection advance coupling.
• Booster pump.
• Camshaft.
• Pushers.
• Plungers with leads or gear sleeves,
• Sleeve liners.
• Recoil springs plungers.
• Pressure valves.
• Fittings.
• Rail.

The principle of the injection pump

The cam shaft receives rotation through the injection advance coupling and a gear from the crankshaft. When the cam shaft rotates, the cam hits the pusher and displaces it, and he, in turn, squeezing the spring, raises the plunger. When raising the plunger, it first closes the inlet channel, and then begins to displace the fuel above it. The fuel is displaced through the discharge valve, which has opened due to the pressure, and is supplied to the injector.

At the moment of movement of the plunger up the screw channel located on it coincides with the drain channel in the sleeve. The remaining fuel above the plunger begins to drain to the axial, radial and screw channels in the plunger and the drain in the sleeve. When the plunger is lowered due to the spring, the inlet channel opens, and the volume above the plunger is filled with fuel from the boost pump.

Changing the amount of fuel supplied to the nozzle by turning the plungers from the rail through the all-mode regulator. When turning the plunger, if the screw channel coincides with the drain earlier, the fuel injected will be less. At the opposite turn, the channels will match later, and the injected fuel will be more.

On some fuel injection pumps (for example, the fuel pump of the tractor T-130), part of the sections is turned off at idle, respectively, part of the engine cylinders is also turned off.

Optional fuel pump units

Injection advance coupling - serves to change the injection advance angle depending on revolutions. By the principle of action is a mechanism that uses centrifugal force. Device:

• Leading coupling half.
• Driven half coupling.
• Loads
• Coupling springs loads.
• Load bearing pins

The principle of the coupling is as follows. At the minimum revolutions, the loads due to the springs are tightened to the center and the position between the couplings is initial, while the injection advance angle is within the adjusted parameter. With increasing speed, the centrifugal force in the cargo increases and spreads them, overcoming the resistance of the springs. In this case, the clutches are rotated relative to each other and the injection advance angle increases.

All-mode regulator - serves to change the amount of fuel supply depending on the engine operation modes: engine start, increase / decrease of revolutions, increase / decrease of load, engine stop. Device:

• Body
• Covers.
• Holder.
• Loads
• Coupling.
• Levers.
• Skoba-backstage.
• Adjusting screws.
• Retractable springs.

The principle of the regulator is as follows:

• Starting the engine: before starting the rail due to the spring is in the position of the maximum fuel supply, therefore when starting up the engine receives the maximum amount of fuel. It promotes quick start. As soon as the engine begins to develop revolutions, and the centrifugal force in the loads begins to grow, overcoming the resistance of the springs, they begin to diverge to the sides and with their internal levers to push the clutch, which will act on the lever, and the lever will pull the rail in the direction of reducing the fuel supply. Turns will be established in accordance with the spring tension.
• Increase in revolutions: when you press the "gas" pedal, the spring, which acts on the rail lever and the clutch, is tensioned. The clutch and rail is shifted, and the centrifugal force in the loads is overcome. The rail is shifted towards increasing the fuel supply, and revolutions are growing.
• Increase in load - with an increase in load and a constant position of the “gas” pedal, the speed decreases, the centrifugal force in the loads also. The loads are folded and make it possible for the clutch, the lever and the rail to move in the direction of increasing the fuel supply. When the load decreases, the revolutions start to increase, the centrifugal force in the loads also, the loads begin to diverge and shift the clutch, the lever and the rail with internal levers in the direction of reducing the fuel supply. Turnovers at the same time stop growing.
• Stopping the engine - when the engine is stopped, the bracket is rotated, the link of the bracket acts on the lever, and the lever - on the rail. The rake moves so much in the direction of decreasing feed that the flow stops and the engine stops

• Direct fuel injection system in gasoline engines
• Battery Rechargeable System

• Plunger animation