Fuel injector units

The fuel injector units are controlled electronically by the engine control module, with a pulse of 110 volts, to

a solenoid.

The units are actuated by engine lubricating oil from the high-pressure system.

The value of the oil pressure can be altered by the engine management system, this pressure is known as

“injection control pressure”.

The injector unit has two main chambers: the oil chamber and the fuel chamber.

The oil chamber receives engine oil from the supply manifold at injection control pressure. A valve, which is

connected to the armature of the solenoid, controls the flow of oil through the oil chamber.

l   When the solenoid is energised, the valve closes an outlet port and opens an inlet port.

l   When the solenoid is de-energised, the valve opens the outlet port and closes the inlet port.

The fuel chamber receives fuel at supply pressure from the supply manifold. A ball-valve and a flat-valve

control the flow of fuel through the chamber.

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Peregrine EDi and 1300 Series EDi

Fuel injection cycle

There are three phases of injection:

l   Phase 1 - Injection (see page 162)

l   Phase 2 - End-of-injection (see page 163)

l   Phase 3 - Fill (see page 164)

These occur during the two strokes of the piston.

l   The injection phase occurs during the down stroke of the piston.

l   The end-of-injection phase and the fill phase occur during the up stroke of the piston.

Key to the colours in the illustrations

Green

Blue

Lubricating oil at injection control pressure

Lubricating oil at discharge pressure

Yellow

Red

Fuel at supply pressure

Fuel at injection pressure

Grey

A moving component, the direction of movement is shown by an arrow on the component

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Peregrine EDi and 1300 Series EDi

Phase 1: Injection

An electrical pulse from the engine control module energises the solenoid (A1). The armature (A2) of the

solenoid pulls the valve (A3) against the pressure of the spring (A6), to close the outlet port (A5), and to open

the inlet port (A7). This allows engine oil at injection control pressure to enter the oil chamber (A4).

The oil pressure above the piston is now greater than the total pressure of the spring (A9) and the fuel below

the piston (A8), this causes the piston to move down into the fuel chamber (A10).

Note: The surface area of the top of the piston is six or seven times greater than the surface area of the bottom

of the piston. This difference gives a mechanical advantage. The mechanical advantage is 6:1 for WK, WL,

WP and WQ engines, and is 7:1 for WM, WN, WR and WS engines. An increase of pressure in the oil chamber

causes an increase of pressure in the fuel chamber that is six or seven times greater.

As the piston moves down into the fuel chamber, the pressure of the fuel below the piston increases. When

this pressure is greater than the supply pressure (B3), the ball-valve (B4) in the fuel chamber closes. This

prevents the entry of more fuel into the chamber.

When the ball-valve closes, the pressure in the fuel chamber rises rapidly and the flat valve (B5) opens to allow

the high-pressure fuel into the nozzle (B6) of the injector unit.

As the piston continues to move down, more oil enters the oil chamber and the pressure in the fuel chamber

continues to increase. When the fuel reaches injection pressure, the nozzle needle (B2) is pushed up from its

seat, against the pressure of the spring (B1), and injection begins.

The period of injection is controlled by the engine control module.

1

2

5

3

6

7

4

8

9

3

4

10

1

2

5

6

A

B

PW239

PW240

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Peregrine EDi and 1300 Series EDi

Phase 2: End-of-injection

The engine control module de-energises the solenoid to start the end-of-injection.

When the solenoid is de-energised, the pressure of the spring (C4) moves the valve up, this closes the oil inlet

port (C5), and opens the oil outlet port (C3). The oil chamber is now closed to oil at injection control pressure

and the oil pressure in the chamber is allowed to discharge through the outlet port into the rocker cover.

When the pressure in the oil chamber is less than the total pressure of the spring (C6) and the fuel in the fuel

chamber, the piston moves up into the oil chamber.

When the piston moves up, the pressure of the fuel in the fuel chamber reduces rapidly. This causes the flat

valve to close. As the piston continues to move up, the fuel pressure above the flat-valve becomes less than

the fuel pressure below it and the valve is kept closed.

The initial rapid reduction of pressure in the fuel chamber allows the spring (D1) to close the nozzle needle. As

soon as the nozzle needle closes it fills more space in the nozzle, which causes the pressure below the flat

valve to increase rapidly. This opens the nozzle needle again and a small amount of fuel is injected, then the

pressure reduces again and the nozzle needle closes. Fuel injection ends.

3

4

1

5

2

6

7

3

2

1

8

C

D

PW241

PW242

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Peregrine EDi and 1300 Series EDi

Phase 3: Fill

When the piston moves up during the end-of-injection phase, the pressure in the fuel chamber (E3) reduces.

When this pressure is less than supply pressure (E2), the ball valve opens, and fuel is allowed to fill the fuel

chamber through holes in the side of the injector unit. The flat-valve is closed by the pressure of the fuel below

it.

2

3

1

E

PW242

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Peregrine EDi and 1300 Series EDi

Fuel filter

To renew the fuel strainer and the canister of the fuel filter

Operation 11-1

Fuel pre-filter

This will normally be fitted between the fuel tank and the engine. Check the filter bowl for water at regular

intervals and drain as necessary. Refer to the User’s Handbook for the correct service intervals.

Caution: It is important that only the genuine Perkins parts are used. The use of incorrect parts could damage

the HEUI fuel injectors.

Note: The fuel filter assembly has a fuel strainer to remove the larger particles from the fuel and a filter canister

to remove the smaller particles. The fuel strainer and the filter canister should be renewed at the same time.

1  Thoroughly clean the outer surfaces of the fuel filter assembly.

2  Use a strap wrench or similar tool to loosen the filter canister, and remove the canister.

1

3  Use a 29 mm (1  /   in) socket spanner to remove the plastic cover (A5) from the fuel strainer. Remove the

8

strainer (A3) and the ’O’ ring (A4) from the cover.

4  Fit a new strainer and a new ’O’ ring to the cover and fit the cover to the filter head.

Caution: Ensure that the open end of the new strainer is toward the filter head.

5  Ensure that the threaded adaptor (A1) is secure in the filter head and that the inside of the head is clean.

Lubricate lightly the seal (A2) of the new canister with clean diesel fuel. Fit the new canister to the filter head

1

and tighten the canister by hand until the seal contacts the filter head. Tighten the canister a further  /   turn by

2

hand. Do not use a strap wrench.

6  Eliminate the air from the fuel filter, see Operation 11-9.

3

1

4

2

5

A

W009

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Peregrine EDi and 1300 Series EDi

Fuel injector units

To remove

Operation 11-2

A faulty fuel injector unit can cause an engine misfire.

Cautions:

l   Special equipment is necessary to test the fuel injector units. This equipment is available at Perkins

distributors.

l   Fuel injector units should be removed by a person who has had the correct training. If the correct procedure

is not used, the cylinders of the engine will be filled with fuel and engine lubricating oil.

The fuel injector units are controlled by the engine management system, which cannot be adjusted by the

operator.

1  Put a container of approximately 2 litres (4 pints) capacity under the drain plug (A2) of the supply manifold.

2  Remove the banjo bolt (B3) of the fuel return pipe, and disconnect the banjo union (B2). Discard the copper

washers.

3  Remove the valve (B1) for the fuel return pipe and drain the fuel from the gallery in the supply manifold (A3).

4  Remove the plug (A2) and drain the lubricating oil from the gallery in the supply manifold (A3). Remove and

discard the ‘O’ ring (A1).

1

2

1

3

2

3

A

B

W212

W213

Continued

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