Powertrain: Clean debut: New powerful two-litre diesel engine is the first engine to fulfil the Euro 6d emission standards

Nov 28, 2018
Stuttgart

In comparison to the preceding model, the new B-Class has consistently new, more efficient engines. The transverse-mounted version of the two-litre OM 654 diesel model series with 110 kW and 140 kW is the first engine to fulfil the Euro 6d norm, which is only mandatory for new models as of 2020. It complements the OM 608 four-cylinder diesel engine with 1.5 litre displacement, up to 85 kW and up to 260 Nm familiar from the A-Class. In addition, two four-cylinder petrol engines from the M 282 model series with 1.33 litre capacity and 100 kW/120 kW will be available at launch. Innovations include cylinder management (in combination with 7G-DCT transmission), delta shape of the cylinder head and particle filter. All engines comply with the Euro 6d-TEMP limits at a minimum. The new B-Class is initially available exclusively with dual-clutch transmissions. New here is the eight-speed 8G-DCT, which is used in combination with the larger diesel engine. Other new engines will follow, as will models with 4MATIC all-wheel drive. The fuel tank has a capacity of 43 litres as standard, with a 51-litre tank optionally available for certain engine variants.

The following five engine variants will be available at the launch of the B-Class:

  • B 180 (100 kW/136 hp, 200 Nm) with 7G-DCT dual-clutch transmission (fuel consumption combined 5.6- 5.4 l/100 km, CO2 emissions combined 128-124 g/km)[3]
  • B 200 (120 kW/163 hp, 250 Nm) with 7G-DCT dual-clutch transmission (fuel consumption combined 5.6-5.4 l/100 km, CO2 emissions combined 129-124 g/km)1
  • B 200 d (110 kW/150 hp, 320 Nm) with 8G-DCT dual-clutch transmission (fuel consumption combined 4.5-4.2 l/100 km, CO2 emissions combined 119-112 g/km) [4]
  • B 220 d (140 kW/190 hp, 400 Nm) with 8G-DCT dual-clutch transmission; fuel consumption combined 4.5-4.4 l/100 km, CO2 emissions combined 119-116 g/km4.

The new OM 654q diesel engine: lighter, more powerful, cleaner

The transverse-mounted version of the latest premium diesel engine family makes its début in the new B-Class. On the interior, the OM 654q corresponds to its longitudinally mounted brother, tapping in to new levels of efficiency thanks to a series of innovations. At the same time, it is the first Mercedes-Benz to already conform to the Level 2 of the RDE (Real Driving Emissions) which do not come into effect until 202, and is certified according to Euro 6d.

Technical highlights include:

  • the stepped bowl combustion system named after the shape of the combustion recess in the piston
  • the combination of an aluminium engine block and steel pistons
  • further-improved NANOSLIDE® coating of the cylinder walls
  • optimised airflow on the intake and exhaust sides and
  • the use of fourth-generation common-rail injection with pressures up to 2050 bar.

There are differences in the engine periphery. The intercooler is arranged as an air-air cooler fixed to the vehicle. Extensive measures with regard to noise, vibration and harshness characteristics contribute to a high level of acoustic comfort. 

These include:

  • Oil pan encapsulation
  • Crankcase dam on the hot side toward the passenger compartment.
  • Injector well cover
  • Design cover with NVH function and
  • air intake and charge air resonator

The new engine is more compact than the preceding model. Components relevant for efficient emissions reduction are installed directly on the engine. Thanks to the near-engine configuration, exhaust aftertreatment has a low heat loss and excellent operating conditions. The measures taken include

  • high and low-pressure exhaust gas recirculation including cooling
  • a diesel oxidation catalytic converter (DOC) to avoid the emission of carbon monoxide (CO) and unburned hydrocarbon (HC)
  • a particulate filter (sDPF) as well as
  • an SCR catalytic converter (selective catalytic reduction) for reducing nitrogen oxides. Ammonia in the form of the carrier AdBlue® is added to the exhaust gases before entering the SCR catalytic converter.

Première in emission control: OM 654q fulfils Euro 6d

Thanks to further improved exhaust aftertreatment, the powerful four-cylinder from the modern OM 654 engine family already meets the Stage 2 RDE (Real Driving Emissions) standard coming into force from 2020, and is certified to Euro 6d. Even in demanding driving situations and under challenging environmental conditions, the B-Class remains within all the emissions limits.

This is achieved by additional selective catalytic reduction (SCR) with an ammonia slip catalyst (ASC) in the exhaust system of the B-Class. This allows a more generous dose of the reduction agent AdBlue®, as any surpluses can be reduced and converted in the second SCR. These surpluses (ammonia slip) particularly occur during fast temperature changes in the exhaust tract, e.g. when moving from city traffic to the motorway.

Despite having a lower displacement than its predecessor, reduced to just under two litres, and weighing around 16 percent less, the new diesel powerplant in the B 220 d has an output of 140 kW (190 hp), precisely 10 kW more than the previous engine, and delivers an NEDC combined consumption of 4.5 litres per 100 kilometres.

Assembly of the OM 654q takes place in the plant Kölleda/Thuringia. The main plant in Untertürkheim/Baden-Württemberg produces the main engine components.

The M 282 petrol engine: four-cylinder with cylinder shutoff

The new entry-level engine in the B 180 and B 200 is the M 282 with a displacement of 1.33 litres. Compared to the previous 1.6-litre engine, the output of this all-aluminium engine has increased by up to eleven percent and the output per litre by no less than 25 percent. This engine excels with very compact dimensions, low weight and high static and dynamic rigidity. The turbocharger features an electronically controlled wastegate: thanks to flexible charge pressure control, it is also possible to set an optimum charge pressure under partial-load conditions.

This is the first four-cylinder Mercedes-Benz engine to feature cylinder shutoff (initially in conjunction with the 7G-DCT transmission). In the partial load range between 1250 and 3800 rpm, and depending on the power requirement, the intake and exhaust valves of the second and third cylinder are closed by valve clearance adjustment. The remaining two cylinders therefore operate under higher loads, and more efficiently. To minimise friction, the cylinder walls are coated using the patented NANOSLIDE® process. The piston skirts have an EcoTough coating. This is a special kind of graphite coating for optimised friction loss and high wear resistance.

Another special technical feature is the delta cylinder head, so called because of its shape. It is slightly higher when installed, but much narrower and lighter than conventional cylinder heads. Further advantages include the semi-integrated intake and exhaust manifolds, which allow compact construction. Daimler holds a patent for the compact arrangement of the high-pressure injection pump with a maximum of 250 bar. The multi-hole injection nozzles are centrally located in the combustion chamber, and injection occurs without the valves being subjected to the jet of fuel.

This new, high-compression four-cylinder engine has a particulate filter as standard. Particular effort was also devoted to noise emissions. The intake air duct features a Helmholtz resonator, the catalytic converter has insulating seals and the cover also has a noise-reducing role.

The new engine will initially be available with the 7G-DCT dual clutch transmission, and later also with a six-speed manual transmission and 4MATIC all-wheel drive.

The M 282 was developed by Mercedes-Benz in cooperation with Renault. It is produced at the Kölleda plant in Thuringia, and in future it will also be produced in Beijing/China. Renault supplies the components of the long block engine.

The OM 608 diesel engine: quieter and cleaner

The new entry-level engine in the B 180 and B 200 is the M 282 with a displacement of 1.33 litres. Compared to the previous 1.6-litre engine, the output of this all-aluminium engine has increased by up to eleven percent and the output per litre by no less than 25 percent. This engine excels with very compact dimensions, low weight and high static and dynamic rigidity. The turbocharger features an electronically controlled wastegate: thanks to flexible charge pressure control, it is also possible to set an optimum charge pressure under partial-load conditions.

This is the first four-cylinder Mercedes-Benz engine to feature cylinder shutoff (initially in conjunction with the 7G-DCT transmission). In the partial load range between 1250 and 3800 rpm, and depending on the power requirement, the intake and exhaust valves of the second and third cylinder are closed by valve clearance adjustment. The remaining two cylinders therefore operate under higher loads, and more efficiently. To minimise friction, the cylinder walls are coated using the patented NANOSLIDE® process. The piston skirts have an EcoTough coating. This is a special kind of graphite coating for optimised friction loss and high wear resistance.

Another special technical feature is the delta cylinder head, so called because of its shape. It is slightly higher when installed, but much narrower and lighter than conventional cylinder heads. Further advantages include the semi-integrated intake and exhaust manifolds, which allow compact construction. Daimler holds a patent for the compact arrangement of the high-pressure injection pump with a maximum of 250 bar. The multi-hole injection nozzles are centrally located in the combustion chamber, and injection occurs without the valves being subjected to the jet of fuel.

This new, high-compression four-cylinder engine has a particulate filter as standard. Particular effort was also devoted to noise emissions. The intake air duct features a Helmholtz resonator, the catalytic converter has insulating seals and the cover also has a noise-reducing role.

The new engine will initially be available with the 7G-DCT dual clutch transmission, and later also with a six-speed manual transmission and 4MATIC all-wheel drive.

The M 282 was developed by Mercedes-Benz in cooperation with Renault. It is produced at the Kölleda plant in Thuringia, and in future it will also be produced in Beijing/China. Renault supplies the components of the long block engine.

The key data of the engine family for the market launch of the B-Class: 

 

 

M 282 (B 200)*

OM 654q (B 220 d)**

Cylinders

Number/arrangement

4/in-line

4/in-line

Valves per cylinder

Number

4

4

Displacement

cc

1332

1951

Displacement of one cylinder

cc

333

488

Cylinder spacing

mm

85

90

Bore

mm

72.2

82

Stroke

mm

81.4

92.4

Bore/stroke

 

1.3

1.12

Rated output

kW/hp

120/163

140/190

at

rpm

5500

3800

Peak torque

Nm

250

400

at

rpm

1620–4000

1.600–2.400

Specific output

kW/l

90

73

Compression

ratio

10.6

15.5

* also available as B 180; ** also available as B 200 d

The 8G-DCT Transmission: More gears, higher torque

In the new B-Class, Mercedes-Benz is for the first time using the new 8G-DCT transmission in connection with the large diesel engine. It has been designed for torque of up to 520 Nm. The gear ratios are closer together on account of the additional gear range, which makes for enhanced ease of shifting and extends the possibility of operating the engine in the best possible operating point. At the same time, the 8th gear has a longer ratio, and at constant speeds on the motorway, for example, rpm is decreased which is good for efficiency and noise comfort.

The weight of the 8G-DCT was reduced by approximately 3.6 kg in comparison to the 7F-DCT. This was made possible by various lightweight design techniques, an internal circuit with synthetic cylinders and a lightweight housing. Despite the additional gear range, the transmission build is not any longer than the 7-speed variant.

The 8G-DCT has a new, fully-integrated direct control with potted electronics. This uses small magnets to aid faster actuation for shorter response times at reduced weight. The 8G-DCT has dry sump lubrication. A light-weight transmission oil with lower viscosity is used. The targeted oiling of the gearing, a reduced amount of oil and a mechanical oil pump with significantly reduced delivery volume ensure efficient oil supply and lubrication. The electrically driven oil pump provides support as required and in active start-stop function it supplies the shift elements of the transmission with hydraulic oil so that the vehicle is ready to drive directly after starting the engine.

B 180 and B 200 have the 7G-DCT dual clutch transmission already familiar from the A-Class. For a low dry weight of 67 kg, the actuators exhibit high mechanical and electrical efficiency. The gears are shifted electro-mechanically, the wet clutches are operated electrohydraulically. The software-controlled clutch allows different shift characteristics – from sporty to particularly comfortable. The driver is able to choose between ECO, Comfort, Sport and Individual. As further functions it allows extended coasting and ECO start/stop. This transmission was developed together with GETRAG, who also produces it. 

[3]Figures for fuel consumption and CO2 emissions are provisional and were determined by the technical service for the certification process in accordance with the WLTP test method and correlated into NEDC figures. EC type approval and certificate of conformity with official figures are not yet available. Differences between the stated figures and the official figures are possible.

[4]The stated figures were determined in accordance with the prescribed measuring method. These are the "NEDC CO2 figures" according to Art. 2 No. 1 Implementing Regulation (EU) 2017/1153. The fuel consumption figures were calculated based on these figures.

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