Powertrain: Power from six or eight cylinders

Jun 24, 2019
Stuttgart/Salt Lake City

The high standards of the new Mercedes-Benz GLS are likewise clearly apparent in its engine line-up. Powerful six and eight-cylinder engines deliver the harmonious motoring comfort and the effortless power that suit the characteristics of this luxurious car. The introduction of the GLS 580 4MATIC marks the world première of a new electrified V8 petrol engine with 48-volt on-board electrical system and integrated starter-generator (combined fuel consumption: 10.1-9.8 l/100 km; combined CO2 emissions: 230-223 g/km)[1]. This engine has a displacement of about four litres and produces an output of 360 kW (489 hp) and 700 Nm of torque, with another 250 Nm of torque and 16 kW/22 V8 hp of additional output temporarily on tap via EQ Boost (more about the V8 in the next chapter). At the market launch, two straight-six diesel engines, which are reserved to the European and Russian markets, and a straight-six petrol engine with EQ Boost for the American and Chinese market will be available.

The two GLS diesel models are powered by the OM 656, the straight­ six engine from the current engine family. It is available in two output levels, as the GLS 350 d 4MATIC with 210 kW (286 hp) and 600 Nm (combined fuel consumption: 7.9-7.6 l/100 km; combined CO2 emissions: 208-200 g/km)2 and as the GLS 400 d 4MATIC with 243 kW (330 hp) and 700 Nm of torque (combined fuel consumption: 7.9-7.6 l/100 km; combined CO2 emissions: 208-201 g/km)2. In both versions, the powerful engine even in demanding driving conditions already complies with the Euro 6d- standard (RDE/Real Driving Emissions Stage 2), which does not come into force until 1 January 2020 for new models and one year later for all vehicles.

This is achieved with, among other things, an additional selective catalytic reduction (SCR) converter with an ammonia slip catalyst (ASC) in the exhaust tract of the GLS. This allows dosing of the AdBlue® reducing agent that is even more closely aligned with the individual driving characteristics because any excessive ammonia surplus in the second SCR converter is broken down further. The AdBlue® tank has a capacity of 31.6 litres. As before, refilling is convenient via a separate pipe behind the fuel filler flap.

Most of the components relevant for efficient emissions reduction are installed directly on the engine. The integrated technology approach combining the new stepped-bowl combustion process, dynamic multi-way exhaust gas recirculation and near-engine emission-control system, combined for the first time with variable valve-lift control, makes further reduced consumption with low emissions possible. Thanks to the near-engine insulated configuration, the emission control system does not suffer great levels of heat loss and generates extremely favourable 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 hydrocarbons (HC),
  • a particulate filter with SCR catalytic function (sDPF), 
  • an SCR catalytic converter (selective catalytic reduction) for reducing nitrogen oxides. For this purpose, ammonia in the form of the carrier AdBlue® is added to the exhaust gases before entering the sDPF, 
  • an additional selective catalytic reduction (SCR) converter with an ammonia slip catalyst (ASC) in the exhaust tract.

The other features of the top-of-the-range engine of the premium diesel family include two-stage turbocharging, the combination of aluminium block and steel pistons as well as further advanced NANOSLIDE® cylinder coating.

Six-cylinder petrol engine for countries without diesel market

The Mercedes-Benz GLS 450 4MATIC as the first petrol model at market launch is available exclusively outside the EU market. Its in-line six-cylinder engine has been electrified with 48-volt technology. Its performance data: 270 kW (367 hp) and 500 Nm of torque, with a further 250 Nm of torque and 16 kW/22 hp available via EQ Boost over short periods. The integrated starter-generator (ISG) is responsible for hybrid functions such as EQ Boost or energy recuperation, while allowing fuel savings that were previously reserved for high-voltage hybrid technology.

ISG eliminates the need for a belt drive for ancillary components at the front of the engine, which reduces its overall length. The slim design of the in-line engine, together with the physical separation of intake/exhaust, creates space for close-coupled emission control. The 48 V on-board electrical system serves not only high power consumers, such as the water pump and air-conditioning compressor, but also the integrated starter-generator (ISG), which also supplies energy to the battery by means of highly efficient energy recuperation.

Nine gears for comfortable and efficient gear shifts

In all variants of the new GLS, power is transmitted by the 9G-TRONIC automatic transmission. The broad ratio spread of gears one to nine allows a clearly perceptible reduction in engine speed and is a decisive factor behind the high level of energy efficiency and ride comfort. The high overall efficiency is reflected in the fuel economy. Shortened shift and response times ensure optimum spontaneity combined with outstandingly smooth gear changes. Particularly in manual mode and S mode, 9G-TRONIC responds immediately and enhances driving pleasure.

The particularly good gear-shifting comfort of the nine-speed automatic transmission is the result of extensive measures. These include the novel direct control system which enables short, barely perceptible gear changes. The combination of twin-turbine torsional damper and centrifugal pendulum technology in the torque converter ensures outstanding drive comfort. An additional electric transmission oil pump is activated in start/stop operation and when the petrol engine is switched off in sailing mode, ensuring a basic supply to the control elements and actuators. The time delay between the desire to move off and the vehicle's actual movement is reduced by the electric transmission oil pump.

The models of the new GLS at a glance:

 

GLS 350 d 4MATIC2

GLS 400 d 4MATIC2

GLS 450 4MATIC
(not for Western Europe)

GLS 580 4MATIC1

Number of cylinders/arrangement

6/in-line

6/in-line

6/in-line

8/V

Displacement (cc)

2925

2925

2999

3982

Rated output (kW/hp)

200/272

243/330

270/367

360/489

at rpm

3400-4600

3600-4000

5500-6100

5500

Additional output EQ Boost (kW/hp)

-

-

16/22

16/22

Rated torque (Nm)

600

700

500

700

at rpm

1200-3200

1200-3000

1600-4500

2000-4000

Add torque EQ Boost (Nm)

-

-

250

250

Combined fuel consumption
(l/100 km)

7.9-7.6

7.9-7.6

n/a

10.1-9.8

Combined CO2 emissions (g/km)

208-200

208-201

n/a

230-223

Emissions class

Euro 6d

Euro 6d

omitted

Euro 6d temp

Acceleration 0-100 km/h (s)

7.0

6.3

5.7

5.3

Top speed (km/h)

227

238

250

250

1 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 a certificate of conformity with official figures are not yet available. Differences between the stated figures and the official figures are possible.

2 The stated figures are the measured "NEDC CO2 figures in conformance with Article 2 No. 1 Implementing Regulation (EU) 2017/1153. The fuel consumption figures were calculated based on these figures. A higher value may be applied as a basis for calculating the motor vehicle tax.

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