Mercedes-Benz OM 651

Mercedes Benz

OM 651
Manufacturer:	Daimler AG
Production period:	since 2008
Design:	Four-cylinder in - line engine
Engines:	1.8 liters (1796 cm³) 2.1 liters (2143 cm³)
Previous model:	OM 646 (in-line four-cylinder) OM 642 (V-six-cylinder)
Successor:	OM 654

The OM 651 engine is a diesel engine from Daimler AG , which was presented in October 2008 in the Mercedes-Benz C 250 CDI BlueEFFICIENCY model. The four-cylinder in - line engine is the successor to the OM-646 four-cylinder series and is also intended to replace the weaker versions of the V6 engine OM 642 . The OM 651 is not a revised version of the OM 646, but has been completely redeveloped.

The engine is preassembled at the Stuttgart plant and finished at MDC Power in Kölleda (Thuringia). The crankcase is supplied by the Fritz Winter and Halberg iron foundries .

technology

Base engine

The engine has a crankcase made of gray cast iron , a light metal - the cylinder head and the cylinder four V-shaped at an angle of 6 ° overhead valves ( four valves per cylinder ), two overhead camshafts and roller cam, which on resting lash compensation elements are mounted.

The camshaft drive is located at the rear end of the engine (output side) in order to keep the overall height at the front end as small as possible. With the engine installed lengthways, this enables a flat engine hood that rises towards the rear in favor of aerodynamics and pedestrian protection. In order to reduce the overall length of the motor, the drive is in two stages : first via gear wheels , as these require less space between the motor and the gearbox, and in the second stage via a single roller chain . The gears also drive the high-pressure fuel pump and two balance shafts on needle bearings ( Lanchester balance ).

The displacement is 1796 cm³ or 2143 cm³ with a bore of 83 mm and a stroke of 83 or 99 mm, with a cylinder spacing of 94 mm. In the 2.1-liter version (with a connecting rod length of 143.55 mm) the engine is designed to be much longer-stroke than its predecessor, which is favorable in terms of higher peak pressure. The compression is 16.2: 1 slightly lower than its predecessor.

Charging and exhaust

The more powerful versions 220 CDI BlueEFFICIENCY and 250 CDI BlueEFFICIENCY two provide turbocharger from BorgWarner in two-stage arrangement for an improved cylinder charging. Both turbines and compressors are connected in series: the exhaust gas first flows through the high pressure turbine, which drives the high pressure compressor, and then through the low pressure turbine. The intake air, in turn, is first passed through the low-pressure compressor and then through the high-pressure compressor. The boost pressure is regulated by an adjustable turbine bypass (similar to a wastegate), which directs the exhaust gas directly to the low-pressure turbine, bypassing the high-pressure turbine. When the engine speed is high, the charge air is routed around the high pressure compressor so as not to overload the high pressure charger. The boost pressure in the 150 kW variant is just under 3 bar (absolute).

The weaker units up to 105 kW have a single turbocharger with adjustable turbine guide vanes (VTG charger) from IHI . All versions have a charge air cooler (intercooler).

There is a cooled exhaust gas recirculation (EGR) with pre-cooler and main cooler. Depending on the engine's operating point, the main cooler is bypassed via an exhaust gas recirculation valve (EGR) manufactured by Handtmann in order to control the temperature of the recirculated exhaust gases.

injection

The common rail operates with a fuel pressure up to 2000 bar. The weaker engine variants have solenoid-operated injectors, whereas the more powerful ones have piezo injectors in which the nozzle needle is operated directly, so that up to five individual injections are possible per combustion process. The closed design of these injectors also eliminates the need for a leakage line.

The high-pressure fuel pump is throttled on the suction side in order to adjust the delivery flow as required. This reduces the heating of the diesel, so that it does not require a cooler, and also reduces the pump drive power.

Cooling and lubrication

The engine has a demand-controlled water pump . The control can shut off the coolant flow by means of a pneumatically operated slide, firstly to use less drive power for the pump and secondly to heat the combustion chambers faster when the engine is cold. The nominal temperature of the coolant is normally 100 ° C, but is reduced to up to 80 ° C under heavy loads and depending on driver behavior.

The oil pump is a vane pump with a pressure-dependent delivery rate. It regulates the pressure in the main oil channel after the oil filter in order to reduce the drive power of the pump when the filter load is low. The piston cooling via oil spray nozzles is switched on or off depending on the map. On the one hand, this reduces the drive power of the oil pump when piston cooling is not required at low loads. On the other hand, when the engine is cold, the higher piston temperature reduces hydrocarbon emissions.

Versions

The OM 651 is currently offered in the passenger car models in ten different performance levels:

OM 651 DE 18 LA red. *

Sales description	model series	Construction period
Displacement: 1796 cm³, output: 80 kW (109 hp) at 3200-4600 / min, torque: 250 Nm at 1400-2800 / min
A 180 CDI A 180 CDI BlueEFFICIENCY	W 176	2013 2012-2013
B 180 CDI B 180 CDI BlueEFFICIENCY	W 246	2013 2011-2013

OM 651 DE 18 LA *

Sales description	model series	Construction period
Displacement: 1796 cm³, power: 100 kW (136 hp) at 3600-4400 / min, torque: 300 Nm at 1600-3000 / min
CLA 200 CDI	C 117	2013-2014
A 200 CDI A 200 CDI BlueEFFICIENCY	W 176	2013–2014 2012–2013
B 200 CDI B 200 CDI BlueEFFICIENCY	W 246	2013–2014 2011–2013

OM 651 DE 22 LA red. *

Sales description	model series	Construction period
Displacement: 2143 cm³, power: 70 kW (95 hp) at 3800 rpm, torque: 250 Nm at 1400-2400 rpm
Vito 110 CDI	W / V 639	since 2010
Sprinter 210 CDI / 310 CDI / 510 CDI Sprinter 210 BlueTEC / 310 BlueTEC / 510 BlueTEC	W 906	2009–2016 2013–2016
Displacement: 2143 cm³, power: 84 kW (114 hp) at 3800 rpm, torque: 300 Nm at 1200-2200 rpm
Sprinter 211 CDI / 311 CDI / 411 CDI / 511 CDI	W 906	since 06/2016
Sprinter 211 CDI / 311 CDI / 411 CDI / 511 CDI	W 907/910	since 2018
Displacement: 2143 cm³, power: 88 kW (120 hp) at 2800-4600 / min, torque: 300 Nm at 1400-2800 / min
C 180 CDI C 180 CDI BlueEFFICIENCY	W / S 204	2013–2014 2010–2013
Displacement: 2143 cm³, power: 95 kW (129 hp) at 3800 rpm, torque: 305 Nm at 1200–2400 rpm
Sprinter 213 CDI / 313 CDI / 513 CDI Sprinter 213 BlueTEC / 313 BlueTEC / 413 BlueTEC / 513 BlueTEC	W 906	2009–2016 2013–2016
Displacement: 2143 cm³, power: 100 kW (136 hp) at 3800 rpm, torque: 330 Nm at 1200–2400 rpm
V 200 CDI / Vito 114 CDI	W / V 447	since 2014
Displacement: 2143 cm³, power: 100 kW (136 hp) at 3400-4000 / min, torque: 300 Nm at 1400-3000 / min
CLA 200 CDI	C 117	2014-2015
GLA 200 CDI	X 156	2013-2015
A 200 CDI	W 176	2014-2015
B 200 CDI	W 246	2014-2015
Displacement: 2143 cm³, power: 100 kW (136 hp) at 3200-4000 / min, torque: 300 Nm at 1400-3000 / min
CLA 200 d	C 117	since 2015
GLA 200 d	X 156	since 2015
A 200 d	W 176	since 2015
B 200 d	W 246	since 2015
Displacement: 2143 cm³, power: 100 kW (136 hp) at 2800-4600 / min, torque: 350 Nm at 1200-2700 / min
C 200 d (with automatic gear)	W / S 205
Displacement: 2143 cm³, power: 100 kW (136 hp) at 2800-3000 / min, torque: 360 Nm at 1600-2600 / min
C 200 CDI C 200 CDI BlueEFFICIENCY	W / S 204	2013–2014 2009–2013
E 200 CDI E 200 CDI BlueEFFICIENCY E 200 BlueTEC	W / S 212	2013–2014 2009–2013 since 2014
Viano 2.0 CDI / Vito 113 CDI	W / V 639	since 2010
Displacement: 2143 cm³, power: 105 kW (143 hp) at 3200 rpm, torque: 350 Nm at 1200-2800 rpm
GLK 200 CDI BlueEFFICIENCY	X 204	since 2010
Displacement: 2143 cm³, output: 105 kW (143 hp) at 3800 rpm, torque: 330 Nm at 1200–2400 rpm
Sprinter 214 CDI / 314 CDI / 514 CDI	W 906	since 06/2016
Sprinter 214 CDI / 314 CDI / 414 CDI / 514 CDI	W 907/910	since 2018

OM 651 DE 22 LA *

Sales description	model series	Construction period
Displacement: 2143 cm³, power: 120 kW (163 hp) at 3800 rpm, torque: 360 Nm at 1400-2400 rpm
Viano 2.2 CDI / Vito 116 CDI	W / V 639	2010-2014
V 220 CDI / Vito 116 CDI	W / V 447	since 2014
Sprinter 216 CDI / 316 CDI / 416 CDI / 516 CDI Sprinter 216 BlueTEC / 316 BlueTEC / 416 BlueTEC / 516 BlueTEC	W 906	since 2009 since 2013
Displacement: 2143 cm³, output: 120 kW (163 hp) at 3800 rpm, torque: 380 Nm at 1400-2400 rpm
Sprinter 216 CDI / 316 CDI / 416 CDI / 516 CDI	W 907	since 2018
Displacement: 2143 cm³, power: 125 kW (170 hp) at 3600-4400 / min, torque: 350 Nm at 1600-3200 / min
GLA 220 CDI	X 156	2013-2015
Displacement: 2143 cm³, power: 125 kW (170 hp) at 3400-4000 / min, torque: 350 Nm at 1400-3400 / min
CLA 220 CDI	C 117	2013-2014
A 220 CDI A 220 CDI BlueEFFICIENCY	W 176	2013–2015 2012–2013
B 220 CDI B 220 CDI BlueEFFICIENCY	W 246	2013–2014 2012–2013
Displacement: 2143 cm³, power: 125 kW (170 hp) at 3400-4000 / min, torque: 400 Nm at 1400-2800 / min
C 220 CDI C 220 CDI BlueEFFICIENCY	W / S / C 204	2013–2015 2009–2013
C 220 BlueTEC C 220 d C 220 BlueTEC BlueEFFICIENCY Edition C 220 d BlueEFFICIENCY Edition	W 205	2014-2015 since 2015 2014–2015 since 2015
GLK 220 CDI GLK 220 CDI BlueEFFICIENCY GLK 220 BlueTEC	X 204	since 2013, 2009–2013 since 2012
E 220 CDI E 220 CDI BlueEFFICIENCY E 220 BlueTEC	C / A 207	2013–2014 2010–2013 2014-2017
E 220 CDI E 220 CDI BlueEFFICIENCY E 220 BlueTEC	W / S 212	2013–2014 2009–2013 2014-2016
E 220 CDI Edition E 220 BlueTEC BlueEFFICIENCY E 220 CDI BlueEFFICIENCY Edition	W 212	2012–2013 since 2013 2012–2013
CLS 220 BlueTEC CLS 220 d	C / X 218	2014-2015 2015-2018
Displacement: 2143 cm³, output: 130 kW (177 hp) at 3400-4000 / min, torque: 350 Nm at 1400-3400 / min
CLA 220 CDI	C 117	2014-2015
B 220 CDI	W 246	2014-2015
Displacement: 2143 cm³, output: 130 kW (177 hp) at 3600-3800 / min, torque: 350 Nm at 1400-3400 / min
A 220 d	W 176	since 2015
CLA 220 d	C 117	since 2015
GLA 220 d	X 156	since 2015
B 220 d	W 246	since 2015
Displacement: 2143 cm³, power: 140 kW (190 hp) at 3800 rpm, torque: 440 Nm at 1400-2400 rpm
V 250 BlueTEC / Vito 119 BlueTEC	W / V 447	since 2014
Displacement: 2143 cm³, power: 150 kW (204 hp) at 4200 rpm, torque: 500 Nm at 1600-1800 rpm
ML 250 BlueTEC	W 166	since 2011
SLK 250 d SLK 250 CDI SLK 250 CDI BlueEFFICIENCY	R 172	since 2015 2013–2015 2012–2013
C 250 CDI C 250 CDI BlueEFFICIENCY	W / S / C 204	2013–2015 2008–2013
C 250 BlueTEC C 250 d	W / S 205	2014–2015 since 2015
C 300 BlueTEC HYBRID C 300 h	W / S 205	2014–2015 since 2015
GLK 250 CDI BlueEFFICIENCY GLK 250 BlueTEC	X 204	2009–2012 2012–2015
GLC 250 d	X 253	since 2015
E 250 CDI E 250 CDI BlueEFFICIENCY E 250 BlueTEC	C / A 207	2013–2014 2009–2013 2014-2017
E 250 CDI E 250 CDI BlueEFFICIENCY E 250 BlueTEC	W / S 212	2013–2014 2009–2013 2014-2016
E 300 BlueTEC HYBRID	W 212	2012-2015
CLS 250 CDI CLS 250 CDI BlueEFFICIENCY CLS 250 BlueTEC CLS 250 d	C / X 218	2013–2014 2011–2013 2014–2015 2015-2018
S 250 CDI BlueEFFICIENCY	W / V 221	2011-2013
S 300 BlueTEC HYBRID S 300 h	W / V 222	2014-2015 2015-2017

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

According to Mercedes-Benz, however, the engine has not yet reached its performance limit. At least 162 kW are still possible. The engine's torque could also be increased to such an extent that its performance data could certainly replace the current OM 642 in the 320 CDI with 165 kW and 540 Nm torque.

All versions meet the Euro 5 emissions standard and the basic design of the engine is designed for the Euro 6 emissions standard, which the ML 250 BlueTEC will meet from 2011.

use

The engine was first offered in the C-Class 204 series in late summer 2008 in a front-runner series known as the “PrimeEdition” (5000 units). This is followed by use in the GLK and, since May 2009, in the E-Class 212 series / 207 series . The other series have also been equipped with the new machine since 2010. Since the end of September 2010, this engine has even been offered in the highest configuration level in the S-Class . Since November 2011 it has also been installed in the B-Class, but here transversely. The displacement was reduced to 1.8 liters.

Technical problems

Shortly after the engine was launched, quality problems with the piezo injectors supplied by Delphi became known. The two more powerful expansion stages with 125 kW and 150 kW were affected by this, but not the less powerful versions, as they have magnetically controlled injectors. The problem usually occurs with a mileage of around 50,000 km. In the event of damage, the affected motors only have a limited power output , as the motors automatically switch to the emergency program to avoid further damage . The vehicle can continue to drive at low speed . Some customers criticized the fact that Mercedes-Benz did not have all injectors of the defective series replaced in the affected vehicle due to capacity bottlenecks at the supplier , but only had individual injectors that had failed. This meant that customers had to visit a workshop up to four times so that all four injectors were replaced. In the further course, however, all injectors were replaced at once. According to various sources, between 2,800 and 50,000 vehicles were affected, with up to 300,000 vehicles mentioned elsewhere. Due to the high failure rate, only a few engines are built with Delphi piezo injectors. The performance of the Delphi magnetic injectors has been increased to 145 kW, so that the 220 CDI and 250 CDI models can also be equipped with it. In addition, Bosch solenoid injectors are occasionally used in the all-wheel drive and M-Class variants.

Another problem is the water pump. In many cases this will leak.

The engine is equipped with a simplex timing chain (instead of a duplex chain). Increased wear on the timing chain and / or on the chain tensioner can be seen with higher mileage. Replacing the timing chain is quite complex, as the timing chain is installed on the rear side of the transmission.

Problems with the chain tensioner became known again at the end of November 2014. The chain tensioner may then fail and engine oil may leak. All vehicles that were produced between February and November 2014 were recalled by the manufacturer.

Exhaust gas affair

According to media reports from Süddeutscher Zeitung, WDR and NDR, the diesel engine OM 651 is part of the investigation by the Stuttgart public prosecutor's office, citing a search warrant from May 2017. This investigates the suspicion that the engine contains an impermissible switch-off device, which means that the exhaust gas values on the test bench are better than in actual use. More than one million vehicles of different vehicle classes are said to be affected, which were sold between 2008 and 2016 in Europe and the USA with inadmissibly high pollutant emissions. In the meantime there has been an official recall in which the defeat devices on the OM 651 engine (and the OM 642 ) were removed. Various models that were built between 2011 and 2018 were affected. In April 2019 it became known that around 60,000 Mercedes-Benz GLK 220 CDI models with the OM 651 engine, which were produced between 2012 and 2015, the legal limit value for nitrogen oxides would be significantly exceeded. There is a suspicion of an impermissible disconnection device

This suspicion has been confirmed for Germany in the officially monitored KBA recalls for:

KBA 8227 - GLC 220d / GLC 250d: 06.2015 to 06.2018
KBA 8251, 8252, 8253, 8314 - Vito 2.2 Diesel: 09.2014 to 09.2016 (sometimes for car registrations in M1, sometimes for commercial vehicle registrations in N1)

The ADAC also publishes:

C 220d / C 250d and C 220, C 250 BlueTEC: 12.2013 to 05.2018
S 300 BlueTEC HYBRID / S 300 h: 12/2013 to 09/2016
ML 250 BlueTEC: 08.2011 to 06.2015
possibly also GLE 250d

A third recall by the KBA was initiated in October 2019.

literature

Joachim Schommers, Johannes Leweux, Thomas Betz, Jürgen Huter, Bernhard Jutz, Peter Knauel, Gregor Renner, Heiko Sass: The new four-cylinder diesel engine for passenger cars from Mercedes-Benz , in: MTZ - Motortechnische Zeitschrift 69 (2008), No. 12 , Pp. 1000-1009, Springer Vieweg, Wiesbaden, December 2008
Joachim Schommers, Peter Lückert, Heiko Sass, Christian Andres: The four-cylinder diesel engine OM651 - One for all , in: ATZ extra - The new A-Class from Mercedes-Benz , pp. 64–67, Springer Vieweg, Wiesbaden, September 2012

Web links

Individual evidence

↑ A miracle engine, which was for Daimler to disaster , faz.net, September 1, 2012

↑ Part 573 Safety Recall Report - Published on November 28, 2014 (engl.) ( Memento of the original dated January 11, 2015 Internet Archive ) Info: The archive link is automatically inserted and not yet tested. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2
↑ RAPEX A12 / 2167/14 notification (Engl.)
^ Hans Leyendecker and Klaus Ott: exhaust scandal. Serious exhaust gas allegations against Daimler. In: Economy. Süddeutsche Zeitung , July 12, 2017, accessed on July 14, 2017 .
↑ List of affected Mercedes models. Retrieved January 9, 2019 .
↑ German authorities discover new cheat software at Daimler. In: nzz.ch . April 14, 2019, accessed April 14, 2019 .
↑ https://www.kba-online.de/gpsg/startServlet?adress=gpsg
↑ https://www.adac.de/infotestrat/reparatur-pflege-und-wartung/rueckätze/suchverbindungen.aspx?Kategorie=Pkw&Hersteller=Mercedes
↑ https://www.n-tv.de/wirtschaft/KBA-erlaesst-Rueckrufbescheid-gegen-Daimler-article21326318.html

[1] A miracle engine, which was for Daimler to disaster , faz.net, September 1, 2012