Fuel Circuit - Engine OM501LA

Mercedes Benz Actros

Fuel Circuit - Engine OM501LA

Pada bab ini, kita akan bahas tentang fuel circuit pada engine yang terpasang pada truck Actros. Untuk beberapa seri mungkin akan berbeda lokasi komponennya.

I Fuel delivery pump
II Injection nozzle
III Fuel filter
IV Unit pump
V MR control unit 
VI Pressure holding valve

1. Through prefilter from fuel tank
2. Check valve
3. Leak oil
4. From unit pumps
5. To unit pumps
6. To fuel delivery pump
7. To fuel filter
8. To injection nozzles
9. Draining filter and flowback of leak oil

Fuel Line

1 Fuel tank
1.1 Fuel strainer (800 µm) 
2 Manual fuel feed pump 
2.1 Fuel prefilter (300 µm) 
For vehicles without code (K81) 
Fuel prefilter without heated water separator
2.2 Fuel prefilter (10 µm) 
For vehicles with code (K81) 
Fuel prefilter with heated water separator
3.1 Assembly valve in fuel feed (opened by pressure)
3.2 Assembly valve in fuel return flow (opened by pressure) 
4 Fuel heat exchanger 
5 Fuel pump 
5.1 Pressure relief valve (9.0 to 12.0 bar)
6 Fuel filter
6.1 Fuel filter drain valve 
6.2 Continuous ventilation in the fuel filter 
6.3 Fuel filter element (1.5µ m) 
7 Injection nozzles in the nozzle holder combinations
8 Throttle in the banjo union at the 
9 Overflow valve (2.0 – 2.6 bar) 
9.1 Throttle in overflow valve 
10.1 Fuel feed connector (in frame)
10.2 Fuel return flow connector (in frame)
11 Throttle in the pressure side fuel feed to the flame starting system (FLA) 
Only in case of vehicles with code (M89) Flame starting system (FLA)  

A6 Engine control (MR) control unit
B10 Fuel temperature sensor
R3 Flame glow plug 
Only for vehicles with code (M89)
Flame starting system (FLA)
Y5 Flame starting system solenoid valve 
Only for vehicles with code (M89)
Flame starting system (FLA)
Y6 Cylinder 1 unit pump 
Y7 Cylinder 2 unit pump
Y8 Cylinder 3 unit pump 
Y9 Cylinder 4 unit pump 
Y10 Cylinder 5 unit pump
Y11 Cylinder 6 unit pump

A Fuel feed line, suction side and / or vacuum side 
B Fuel feed line, pressure side 
C Fuel high-pressure line 
D Fuel return line 
E Fuel short circuit line 
F Suction or vacuum side fuel feed line to the fuel prefilter with a heated water separator 
Only for vehicles with code (K81) Fuel prefilter with heated water separator 
G Pressure side fuel feed line to the flame starting system (FLA) 
Only for  vehicles with code (M89) Flame starting system (FLA) 

Pump Line Nozzle – PLD 

1 O-ring 

2 Leakage drilling 

3 Cover plate 

4 Valve stop 

5 Thread for union nut 

6 Valve spring 

7 Intermediate plate 

8 Armature plate 

9 Unit pump solenoid (electromagnet) 

10 Valve spring base 

11 Spring cup 

12 Float needle 

13 High pressure chamber 

14 Pump housing 

15 Sleeve 

16 Pump element 

17 Roller tappet spring 

18 Spring plate (roller tappet) 

19 Roller tappet. 

20 Oil hole 

21 Roller 

22 Roller tappet pin 

Unit Pump Classification

Klasifikasi unit pump berupa nomor 14 digit (C) yang terletak di odel plate unit pump. Kode ini dimasukan melalui DAS dalam menu “Replace Unit Pump”. Memasukan kode unit pump ini perlu dilakukan agar mendapatkan engine smooth running serta penyemprotan bahan bakar yang efektif dan efisien. Agar didapat horse power maksimal yang tersimpan dalam control unit MR.

A MB number

B Certification number

C Unit pump number

D Barcode

E, G,H Manufactur information

F Manufacturer barcode

Construction of PLD

1 Unit pump 

2 High pressure pipe 

3 Pressure pipe connection 

4 Nozzle holder combination 

5 Pump element 

6 Supply passage 

7 Solenoid valve 

8 High pressure chamber 

9 Return flow passage 

10 Solenoid 

11 Armature plate 

12 Float needle 

13 Injection nozzle 

B Fuel feed 

C Fuel high-pressure 

D Fuel return flow 

Fuel Injection by PLD

• Suction Stroke

Selama suction stroke pump element (10) bergerak turun. Solenoid valve (7) de-energized sebagai akibatnya bahan bakar dengan tekanan yang konstan pada fuel low-pressure section masuk kedalam high pressure chamber unit pump (9) melalui saluran supply (8). 

Note :

Energized : mendapat arus listrik

De – energized : tidak mendapat arus listrik

• Pre Stroke

Selama pre stroke pump element (10) bergerak keatas karena solenoid valve (7) energized tetapi valve (6) belum tertutup penuh, sedikit bahan bakar  tertekan ke dalam displacement chamber (2) kemudian kembali ke saluran balik (3).

• Delivery Stroke

Sesaat setelah valve (6) tertutup, sementara pump element (10) bergerak ke top dead center maka unit pump berada pada posisi delivery stroke. Penyemprotan bahan bakar terjadi pada saat ini. Dalam hal ini tekanan bahan bakar di dalam high pressure chamber (9) meningkat sampai 1800 bar.

 

• Residual Stroke

Solenoid valve (7) de – energized kemudian valve (6) terbuka (akhir delivery stroke) maka bahan bakar di dalam high pressure chamber (9) berkurang. Sisa bahan bakar yang tertekan oleh pump element (10) sampai pada cam lobe  unit pump (1) sehingga masuk ke dalam displacement chamber (2) dan kemudian keluar melalui saluran balik (3). Displacement chamber sebagai expansion chamber untuk pressure peaks (tekanan puncak) dari unit pump saat residual stroke.

Injection Nozzle Assembly

Nozzle holder dan injector nozzle terletak secara  vertical ditengah-tengah cylinder. Injector nozzle dengan 8 lubang yang ada dilindungi oleh nozzle protection sleeve. 

1 Injection line

3 Thrust bolt

4 O-ring

5.1 Pressure pipe connection with anti-twist lock (interference-fit ball)

5.2 Pressure pipe connection without anti-twist lock

6 Nozzle holder combination

7 O-ring

8 Bolt

9 Tensioning arm

10 Seal

11 End cover of constant throttle