Mercedes-Benz OM 646 / OM 647 / OM 648

Mercedes Benz
OM 646, OM 647, OM 648
Manufacturer:	Mercedes Benz
Production period:	2002-2010
Design:	Inline four cylinder OM 646 Inline five cylinder OM 647 Inline six cylinder OM 648
Engines:	2.2 liters (2148 cm³) 2.7 liters (2685 cm³) 3.2 liters (3222 cm³)
Previous model:	OM 611 (4-cylinder) OM 612 (5-cylinder) OM 613 (6-cylinder)
Successor:	OM 651 (4-cylinder) OM 642 (6-cylinder)

The OM 646 by Mercedes-Benz is a four cylinder - diesel engine with common-rail direct injection . Vehicles with this engine type mostly have 200 CDI and 220 CDI in their sales designation. The engine type represents a further development of the OM 611 .

The article also covers the engines OM 647 ( 270 CDI ) with five cylinders and OM 648 ( 280 CDI, 320 CDI ) with six cylinders, also in- line engines that are technically closely related to the OM 646, as well as the four-cylinder OM 644 as a variant for the transverse installation in the Chrysler PT Cruiser .

These engines were mainly installed in several model series between 2002 and 2010, including the C-Class and E-Class , as six-cylinder units also in the S-Class and in vans ( Sprinters ).

technology

General

The Mercedes-Benz OM 646 is a four-cylinder diesel engine with two overhead camshafts which operate the 16 valves via hydraulic valve lifters. For the first time, the OM 646 was sold under the name E 220 CDI when the E-Class was launched. In direct comparison to the predecessor, the consumption could be reduced again and the engine output increased. This is due to modifications to over 80 components. An on-board diagnosis system was installed to ensure that the exhaust gas values ​​are continuously observed, which monitors all components in the engine and exhaust system that are relevant to exhaust emissions. To improve running smoothness, the more powerful models (220 CDI) were equipped with two Lanchester balance shafts. They rotate in opposite directions to each other at double the crankshaft speed and eliminate inertia forces that arise from the piston movement.

The mechanical fuel feed pump has been replaced by an electrical variant that does its job in the tank. To ensure sufficient interior heating to ensure a was PTC - heater installed. Compared to its predecessor, it is not the coolant that is heated here, only the air flowing into the interior. From 2003, a soot particle filter was initially offered as an option and later as standard in conjunction with the Euro 4 emissions standard.

The engine type OM 644 is a special version of the OM 646 for front-wheel drive transverse installation in the Chrysler PT Cruiser . It was released in two performance levels, first for the Euro 3 emissions class , then for Euro 4 .

injection

OM 646 EN 22 LA engine without intake silencer and acoustic cover

This engine type is the first to use 3rd generation common rail direct injection . The system supplier is Bosch . As before, fuel is distributed via a common fuel line (common rail) in which the fuel pressure is kept continuously high by a high-pressure pump. The system pressure has been increased compared to the previous engine. The fuel enters the solenoid valve-controlled injection nozzles through the pipe, from which it is injected through seven holes into the combustion chamber at a pressure of up to 1600 bar. The new injection nozzles distribute the fuel even more finely in the combustion chamber. New from this engine type are double pilot injections, by means of which a small amount of fuel is introduced into the cylinder before the actual combustion and is burned there. This preheats the combustion chamber more effectively, which lowers the rise in temperature and pressure during the main combustion. This ensures smoother running. The high-pressure fuel pump is regulated by volume flow and pressure via a quantity control valve and a pressure control valve.

Charging

As with the OM 611 of the CDI series II, the engine is charged by a turbocharger with variable turbine geometry . It has adjustable guide vanes on the exhaust side , which ensure that the boost pressure builds up more quickly. This improves the cylinder filling and thus also the torque. This reduces the so-called turbo lag. The boost pressure control is achieved by adjusting the guide vanes. In contrast to the previous model, this is electronically controlled. The engines in the Mercedes Sprinter are excluded from this. These are implemented in vehicles with a slightly higher engine via a high and low pressure charger (two-stage charging) using negative pressure. A boost pressure control flap and a wastegate are used, which significantly improve the efficiency and responsiveness of the engine.

A charge air cooler is installed to cool down the compressed hot charge air and thus bring more oxygen into the combustion chamber .

Intake tract

In the intake tract of the OM 646, the EKAS (intake duct shut-off) known from the OM 611 is used. One of the two inlet ports per cylinder, the tangential port, can be switched off at low engine speeds. The sucked in air now flows entirely through the specially shaped second channel, the swirl channel. The resulting swirl leads to a better mixture formation, whereby a better combustion is achieved. The EKAS is electronically controlled and works continuously. In contrast to the predecessor, the pneumatically controlled exhaust gas recirculation valve has been replaced by an electronically controlled variant. It reduces excess air and lowers temperatures by adding exhaust gases to the fresh air drawn in. This reduces nitrogen oxide emissions and combustion noises. To regulate the exhaust gas recirculation, a hot-film air mass meter is installed, which enables an exact measurement of the air mass sucked in.

OM 644

For the cooperation with Chrysler in the USA, a four-cylinder version for transverse installation in the Chrysler PT Cruiser as a 2.2 CRD was designed in advance from the year 2000 . This layout change is also to be regarded as a forerunner of the later A- and B-class engine, also for the transverse installation. At first it was similar to the predecessor OM 611 in terms of the combustion process and other technology, but already introduced the numbering of the next engine generation. In the course of the further development of CDI technology, the PT Cruiser also received an engine version with higher power and better emission classification Euro 4 , see the following section on EVO.

OM 646 EVO

In 2006, the OM 646 EVO was presented as part of the E-Class facelift. It is a further developed variant of the OM 646 in which over 90 components have been modified. The compression ratio has been reduced from 18.0: 1 to 17.5: 1 by installing taller pistons and shorter connecting rods. In addition, a new turbocharger with modified charge air cooling was installed. A structure-borne noise sensor in the injection system allows the fuel to be metered in accordance with requirements. The cylinder head has been redesigned to achieve even more effective engine cooling. The air duct has also been redesigned. This enabled pressure loss and noise emissions to be reduced. The glow plugs are made of ceramic instead of metal for improved engine starting and cold running behavior . They enable higher annealing temperatures. The balancer shafts previously known from the more powerful versions found their way into all OM 646 EVO engines. With the revision, the engines then reached the Euro 4 emissions class (previously Euro 3 ).

Five-cylinder OM 647 and six-cylinder OM 648

With the exception of the balancer shafts, the changes from the OM 611 to the OM 646 were also adopted for the OM 612 (five-cylinder) and OM 613 (six-cylinder) series. This is how the OM 647 and OM 648 series emerged, which differ from the OM 646 in terms of their number of cylinders; The bore and stroke are the same for all engines in this engine family. The modifications of the OM 646 EVO (four-cylinder) no longer benefited the OM 647 (five-cylinder) and OM 648 (in-line six-cylinder) series, as these were replaced by weaker variants of the subsequent OM 642 V6 engine .

Data

Sales description	Engine type *	Model	Power at (1 / min)	Torque at (1 / min)	construction time
4 cylinder
Displacement: 2.2 L 2148 cm³, bore × stroke: 88 × 88.3 mm
Chrysler PT Cruiser 2.2 CRD	OM 644 DE 22 LA (transverse installation)	644.981	89 kW (121 hp) at 4200	300 Nm at 1600-2600	2000-2005
		644.982	110 kW (150 PS) at 4000	330 Nm at 1800–3200	2006-2010
Vito 109 CDI ( W 639 )	OM 646 DE 22 LA red.	646.983	65 kW (88 PS) at 3800	220 Nm at 1400-2500	2003-2006
			70 kW (95 hp) at 3800	250 Nm at 1400-2600	2006-2010
Vito 111 CDI, Viano 2.0 CDI ( W 639 )		646.982 red.	80 kW (109 PS) at 3800	290 Nm at 1600-2500	2003-2006
			85 kW (116 hp) at 3800	290 Nm at 1600-2600	2006-2010
			80 kW (109 PS) at 3800	290 Nm at 1600–2400	2006–2010 ( 4MATIC only )
Vito 115 CDI Viano 2.2 CDI ( W 639 )	OM 646 DE 22 LA	646.982	110 kW (150 PS) at 3800	330 Nm at 1800–2400	2003-2010
Sprinter 209 CDI, 309 CDI, 509 CDI ( W 906 )	OM 646 DE 22 LA	646.984	65 kW (88 PS) at 3800	220 Nm at 1600-2600	2006-2009
Sprinter 211 CDI, 311 CDI, 411 CDI, 511 CDI ( W 906 )		646.985	80 kW (109 PS) at 3800	280 Nm at 1600–2400	2006-2009
Sprinter Classic 311 CDI		-	80 kW (109 PS) at 3800	280 Nm at 1600–2400	2013 – today
Sprinter 213 CDI, 313 CDI ( W 906 )		646.986	95 kW (129 hp) at 3800	305 Nm at 1200–2400	2006-2009
Sprinter Classic 413 CDI		-	100  kW (136 hp) at 3800	320 Nm at 1800–2200	2013 – today
Sprinter 215 CDI, 315 CDI, 415 CDI, 515 CDI ( W 906 )		646.989 646.990	110 kW (150 PS) at 3800	330 Nm at 1200–2400	2006-2009
C 220 CDI ( W / S / CL 203 )	OM 646 DE 22 LA	646.963	105 kW (143 hp) at 4200	340 Nm at 2000	2003-2004
			110 kW (150 PS) at 4200	340 Nm at 2000	2004-2007
C 200 CDI ( W / S 204 )	OM 646 DE 22 LA EVO red.	646.811 red.	100 kW (136 hp) at 3800	270 Nm at 1600-3000	2007-2009
C 200 CDI BlueEFFICIENCY ( W 204 )		646.812			2008-2009
C 220 CDI ( W / S 204 )	OM 646 DE 22 LA EVO	646.811	125 kW (170 hp) at 3800	400 Nm at 2000	2007-2009
CLC 200 CDI ( CL 203 )	OM 646 DE 22 LA red.	646.962	90 kW (122 hp) at 4200	270 Nm at 1600-2800	2008-2010
CLC 220 CDI ( CL 203 )	OM 646 DE 22 LA	646.963	110 kW (150 PS) at 4200	340 Nm at 2000	2008-2010
CLK 220 CDI ( C 209 )	OM 646 DE 22 LA	646.966	110 kW (150 PS) at 4200	340 Nm at 2000	2005-2009
E 200 CDI ( W 211 )	OM 646 DE 22 LA red.	646.951	75 kW (102 PS) at 4200	235 Nm at 1800	2003-2006 (taxi variant)
			90 kW (122 hp) at 4200	270 Nm at 1400-2800	2003-2006
E 200 CDI ( W / S 211 )	OM 646 DE 22 LA EVO red.	646.820 646.821	100 kW (136 hp) at 3800	340 Nm at 2000	2006-2009
E 220 CDI ( W / S / VF 211 )	OM 646 DE 22 LA	646.961	110 kW (150 PS) at 4200	340 Nm at 2000	2002-2006
	OM 646 DE 22 LA EVO	646.821	125 kW (170 hp) at 3800	400 Nm at 2000	2006-2009
5 cylinder
Displacement: 2.7 L 2685 cm³, bore × stroke: 88 × 88.3 mm
E 270 CDI ( W / S / VF 211 )	OM 647 DE 27 LA	647.961	130 kW (177 hp) at 4200	400 Nm at 1800–2600 (425 at 2000)	2002-2005
6 cylinder
Displacement: 3.2 L 3222 cm³, bore × stroke: 88 × 88.3 mm
E 280 CDI ( W / S 211 )	OM 648 DE 32 LA red.	648.961 red.	130 kW (177 hp) at 4200	425 Nm at 1800-2600	2005
E 320 CDI ( W / S 211 )	OM 648 DE 32 LA	648.961	150 kW (204 hp) at 4200	500 Nm at 1800	2003-2005
S 320 CDI ( W / V 220 )		648.960			2002-2005

 * Engine designation is encoded as follows: OM = oil engine (diesel), series = 3 digits, DE = direct injection, displacement = deciliters (rounded), A = exhaust gas turbocharger, L = charge air cooling, red. = reduced performance, EVO = further development

Web links

Commons : Mercedes-Benz OM646  - Collection of Pictures, Videos and Audio Files

Individual evidence

1. ↑ Archived copy ( memento of the original dated November 8, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. 
2. ↑ http://www.jesmb.de/news/news/w211.htm
3. ↑ http://www.autointell.de/News-deutsch-2003/Mai-2003/Mai-2003-1/Mai-02-03-p02.htm
4. ↑ http://www.jesmb.de/news/news/w203-2.htm
5. ↑ http://mercedes-typen.de/blog/om-646.html  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
6. ↑ http://www.mercedes-benz.de/content/media_library/germany/mpc_germany/de/mercedes-benz_deutschland/transporter_ng/neue_transporter/vito/transporter_vito_preisliste.object-Single-MEDIA.download.tmp/MB_PL_VITO_2009_09_1September_0.pdf  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
7. ↑ http://www.auto-motor-und-sport.de/mercedes-viano-2.0-cdi-lang-17785.html
8. ↑ http://www.auto-motor-und-sport.de/mercedes-viano-2.0-cdi-4-matic-kompakt-17777.html
9. ↑ http://www.ultimatespecs.com/?option=4&brand=13&model=499&car=2823
10. ↑ http://www.mercedes-benz.bg/content/media_library/hq/hq_mpc_reference_site/van_ng/new_vans/models/sprinter_906/pickup/product_information/technical_data/engines/sprinter_pickup_engines_01_1294_de-COM_09.fownload8_pdownload /Sprinter_Sprinter_Sprinter_Motor_Data_de_COM_09-2008_j.pdf
11. ↑ http://www.carfolio.com/specifications/models/car/?car=113025
12. ↑ http://www.carfolio.com/specifications/models/car/?car=130350
13. ↑ http://www.carfolio.com/specifications/models/car/?car=192478
14. ↑ Archived copy ( memento of the original from December 17, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. 
15. ↑ http://www.carfolio.com/specifications/models/car/?car=152845
16. ↑ http://www.carfolio.com/specifications/models/car/?car=169488
17. ↑ http://www.carfolio.com/specifications/models/car/?car=169477
18. ↑ http://www.ultimatespecs.com/?option=4&brand=13&model=354&car=1525
19. ↑ http://www.carfolio.com/specifications/models/car/?car=106887
20. ↑ http://www.carfolio.com/specifications/models/car/?car=142692
21. ↑ http://www.carfolio.com/specifications/models/car/?car=90904
22. ↑ http://www.carfolio.com/specifications/models/car/?car=142637
23. ↑ http://www.carfolio.com/specifications/models/car/?car=168795
24. ↑ Archived copy ( memento of the original from October 12, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
25. ↑ http://www.ultimatespecs.com/?option=4&brand=13&model=489&car=2539
26. ↑ http://www.ultimatespecs.com/?option=4&brand=13&model=494&car=2737