Mercedes-Benz ML 63 AMG Efficiency and superlative performance


Engine and power transmission: Lower fuel consumption, higher performance

  • AMG 5.5-litre V8 biturbo engine with 386 kW (525 hp)
  • Output boosted by 24 kW (32 hp) with AMG Performance package
  • Scintillating power delivery, pulling power and engine sound
  • Fuel consumption reduced by 4.7 litres/100 km or 28 percent
  • Standard-fit ECO start/stop function helps to save fuel
  • AMG SPEEDSHIFT PLUS 7G-TRONIC with three transmission modes

ML 63 AMGHigher output but lower consumption: the new ML 63 AMG will help Mercedes-AMG achieve its goal of continuously reducing fuel consumption and emissions in new models over the coming years whilst also further enhancing the brand value “Driving Performance”. Despite an increase in maximum output from 375 kW (510 hp) to 386 kW (525 hp) compared to the outgoing model, the new ML 63 AMG has relatively low fuel consumption of 11.8 litres per 100 kilometres (NEDC combined, 276 g CO2/km), making the high-performance SUV one of the best in its competitive segment.

Output is up 11 kW (15 hp) yet fuel consumption has been cut by 4.7 litres per 100 kilometres – or 28 percent – and the peak torque of 700 newton metres is 70 newton metres higher. Customers who specify the optional AMG Performance package get an output of 410 kW (557 hp) and a torque of 760 newton metres – with identical NEDC consumption figures. The variant with AMG Performance package differs by virtue of a charge pressure increased from 1.0 to 1.3 bar, an engine cover made of high-quality genuine carbon fibre, red-painted callipers and the AMG performance steering wheel with DINAMICA microfibre in the grip area.

Rich torque curve for scintillating power delivery

The scintillating power delivery is one of the defining features behind the outstanding driving impression in the ML 63 AMG: the effortless increase in speed is characterised by a rich torque curve. Some 700 newton metres are on tap across a wide engine speed range of 1750 to 5000 rpm – or 760 newton metres from 2000 to 5000 rpm if the AMG Performance package is specified. The emotive, hallmark-AMG eight-cylinder sound produced by the AMG sports exhaust system’s two chromed twin tailpipes likewise has full license to thrill.

A glance at the performance figures reinforces this impression: the ML 63 AMG accelerates from zero to 100 km/h in 4.8 seconds, and with the AMG Performance package the SUV reaches the 100 km/h mark in 4.7 seconds. The top speed of both engine variants is 250 km/h (electronically limited).

A paragon of efficiency: the AMG 5.5-litre V8 biturbo engine

Key to these performance figures is the AMG V8 powerplant with in-house designation M 157: the AMG 5.5-litre V8 biturbo engine premiered in 2010 in the S 63 AMG and CL 63 AMG. It has also been the dynamic driving force behind the E 63 AMG and CLS 63 AMG since earlier in 2011. The M 157 is a paragon of efficiency and boasts a wealth of technological highlights: on account of higher thermodynamic efficiency, the combination of twin turbochargers, direct petrol injection and spray-guided combustion allows better fuel economy and results in lower exhaust emissions. Fast and precise piezo injectors inject the fuel into the combustion chambers and ensure exceptionally fine distribution of the fuel drops around the air in combustion chamber. An electric low-pressure pump sends the fuel from the tank to a high-pressure pump in the engine compartment at a pressure of 6 bar. The pressure of the fuel in the high-pressure rail is fully variable on demand between 100 and 200 bar, ensuring agile response in any driving situation.

Further highlights of the innovative and unique eight-cylinder powerplant from Affalterbach include an all-aluminium crankcase, four valves per cylinder with camshaft adjustment, air/water intercooling, alternator management and the standard-fit ECO start/stop function. Whereas the previous AMG 6.3-litre V8 naturally aspirated engine had a displacement of 6208 cc, the new AMG 5.5-litre V8 biturbo engine needs just 5461 cc.

Key data at a glance:

Cylinder arrangement V8
Cylinder angle 90°
Valves per cylinder 4
Displacement 5461 cc
Bore x stroke 98.0 x 90.5 mm
Cylinder spacing 106 mm
Compression ratio 10.0 : 1
Output 386 kW (525 hp) at 5250 rpm 410 kW (557 hp) at 5750 rpm*
Output per litre 71 kW (96 hp) 75 kW (102 hp)*
Max. torque 700 Nm at 1750-5000 rpm 760 Nm at 2000-5000 rpm*
Torque per litre 128 Nm 139 Nm*
Maximum engine speed 6400 rpm
Engine weight (dry) 204 kg
Power/weight ratio 0.39 kg/hp 0.36 kg/hp*
Fuel consumption, NEDC combined 11.8 l/100 km
CO2 emissions 276 g/km
Efficiency class F
Acceleration 0-100 km/h 4.8 s 4.7 s*
Top speed 250 km/h**

*With AMG Performance package **Electronically limited

Two exhaust gas turbochargers located next to the cylinder banks supply the eight cylinders with fresh air. At their maximum speed of 185,000 rpm under full load, the two turbochargers force 1750 kg of air per hour into the combustion chambers. The maximum charge pressure is 1.0 bar, or 1.3 bar if the AMG Performance package is included. Thanks to their special, compact design – the turbine housings are welded to the exhaust manifold – there are significant space advantages, and the catalytic converters also heat up more rapidly.

The AMG V8 is the first turbocharged engine to dispense with the usual blow-off valve. This neat solution enabled the compressor housing to be made extremely compact. To ensure agile responsiveness with no time lag, all the air ducts in the intake tract are as short as possible. The wastegate valve, which reduces the pressure in the exhaust system during negative load changes, is vacuum-controlled via an electropneumatic converter. This allows dethrottling under partial loads, which in turn lowers the fuel consumption.

As was already the case in the AMG 6.0-litre V12 biturbo engine, the eight-cylinder direct-injection unit uses particularly efficient air/water intercooling. The low-temperature cooler with its water circulation is space-savingly accommodated within the V of the cylinder banks. It effectively cools down the intake air compressed by the turbochargers before it enters the combustion chambers, and maintains a constantly lower intake temperature under full load. The large radiator at the car’s front end ensures defined cooling of the water circulating in the low-temperature circuit. Extremely short charge-air ducting makes for optimum responsiveness. The stainless-steel pressure pipes for the fresh and charge air are produced by the hydroforming process, have a wall thickness of only 0.8 millimetres and are designed for very low pressure loss.

All-aluminium crankcase with Silitec cylinder liners

The crankcase for the AMG 5.5-litre V8 biturbo engine is made of diecast aluminium. The low (dry) engine weight of 204 kilograms is the result of uncompromising lightweight construction methods and gives the vehicle balanced weight distribution. The bearing cover for the main crankshaft bearings, made of grey cast iron, is bolted to the crankcase for high rigidity. Cast-in Silitec cylinder liners ensure that the eight pistons operate with low friction.

Drilled ventilation holes in the crankcase lead to a higher output and fuel savings under partial load: above the bearing blocks there are longitudinally drilled holes which connect the adjacent crankcase cavities. Normally the upward and downward movement of the pistons causes air to be forced into and extracted from the sump, which leads to increased internal friction losses and therefore a reduction in output. The ventilation holes prevent this by ensuring effective pressure compensation between the cavities. The forged crankshaft made of the high-quality steel alloy 38MnS6BY (a combination of the chemical elements manganese, sulphur, boron and yttrium) rotates in five main bearings, has eight counterweights and is optimised with respect to torsional rigidity, inertia, low rotating masses and durability. A two-mass viscous damper mounted at the front reliably eliminates vibrations. Each connecting rod journal on the crankshaft carries two forged, cracked connecting rods. In the interests of low mechanical friction and high wear resistance, the eight lightweight pistons have a metallic contact surface. Pressure-controlled oil-spray nozzles in the crankcase ensure that the highly stressed piston crowns are efficiently cooled.

Four-valve technology with variable camshaft adjustment

Perfect charging of the combustion chambers is ensured by large intake and exhaust valves, of which there are two per cylinder. The exhaust valves, which are subject to high thermal loads, are sodium-cooled and hollow in order to reduce weight. Four overhead camshafts operate the 32 valves via low-maintenance, low-friction cam followers. The infinitely variable camshaft adjustment within a range of 40 degrees on the intake and exhaust sides depends on the engine load and engine speed, leading to outstanding output and torque values. This also results in consistent idling at a low speed.

Depending on the engine speed, valve overlap can be varied for the best possible fuel/air supply to the combustion chambers and efficient removal of the exhaust gases. The variable camshaft adjustment is carried out electromagnetically via four pivoting actuators, and is controlled by the engine control unit. The camshafts are driven by three high-performance silent chains, which have considerable advantages in noise comfort compared to cylinder roller chains.

Innovative oil supply and water cooling

Efficient oil delivery under all load and operating conditions is ensured by an oil pump with an electrically controlled compression stage. The oil pressure can be varied between 2 and 4 bar, which has advantages in terms of friction and fuel consumption. An extraction stage integrated into the oil pump for the two turbochargers prevents oil from being entrained into the charge air and exhaust gases, thereby helping to reduce emissions even further. Both the sump and the extraction point have been optimised for maximum lateral acceleration and efficient lubrication. The oil capacity is 10.5 litres.

The combined water/oil cooling system is a clever solution: after a cold start, initially the engine oil is only cooled via the oil/water heat exchanger. If the cooling performance of the very compact cooler is insufficient, the flow is additionally directed through the external engine oil/air cooler by an oil thermostat. The advantage of this system is that the engine oil warms up more rapidly, as the engine coolant warms up faster and the oil is later cooled by the coolant. A selectable water thermostat ensures rapid warming of the coolant when starting the engine and driving off. Large intakes in the AMG front apron ensure an effective flow of air to the water, engine oil, charge-air and transmission oil coolers.

The engine coolant is cooled using the particularly efficient crossflow principle. There is a transverse flow of coolant through both the crankcase and the cylinder heads. Additional cooling slots in the cylinder head allow more efficient cooling of the combustion chambers, which has advantages during combustion: it enables earlier ignition timings to be chosen without incurring the risk of knocking.

Alternator management and optimised belt drive

Further factors which help to ensure low fuel consumption include the optimised belt drive, on-demand control of all ancillary units and pumps, and alternator management: whenever the V8 engine is on the overrun or when braking, kinetic energy is used to charge the battery rather than being wasted as heat in the usual way. In all other operating modes a combination of electrical-system and alternator management enables the alternator to be kept at a low voltage. This reduces the load on the engine and makes for fuel savings of around 0.15 litres per 100 kilometres according to the NEDC standard, and up to 0.2 litres per 100 km in city traffic with its frequent overrun and braking phases.

Highly efficient engine electronics for every function

All the engine functions are executed and controlled by a particularly efficient Bosch MED 17.7.3. control unit. This state-of-the-art engine computer not only controls the direct petrol injection, the charge pressure, the camshaft adjustment and the variable oil supply, but also communicates with all the other onboard control units, such as the one for the AMG SPEEDSHIFT PLUS 7G‑TRONIC. The microprocessor has more than 30,000 different parameters and functions stored in its memory, and is able to perform up to 260 million individual operations per second. To reduce the load on the engine control unit, the eight individual ignition coils have an integral electronic module known as an ignition amplifier at each cylinder. These ensure a strong ignition spark at all engine speeds and under all load conditions. The highly precise fuel distribution of the piezo injectors is handled by eight intelligent high-voltage output stages.

New catalytic converter housings for low exhaust emissions

Low exhaust emissions, compliance with country-specific standards, a characteristic AMG engine sound and a weight-optimised design – the requirements for the exhaust system of the new AMG 5.5-litre V8 biturbo engine were manifold and complex. The ML 63 AMG complies with the EU-5 emission standards, as well as meeting all the requirements of the US market (LEV-II standard, On-Board Diagnosis II and lambda sensor diagnosis).

The turbochargers are welded to the exhaust manifolds, while air gap-insulated manifolds with an inner shell measuring only 1.2 millimetres in thickness allow a rapid catalytic converter response. For efficiency and to save space, this concept has a tandem catalytic converter housing on each side of the vehicle: adjacent to the firewall, two thin-walled ceramic substrates are grouped into each housing. This solution makes the previous, additional underbody catalytic converters unnecessary. The two ceramic substrates differ to ensure rapid and efficient emission control: the front one is coated with palladium, while the rear one has a bimetal coating of palladium and rhodium. One lambda sensor per row of cylinders is located in front of each catalytic converter housing, and there is a lambda diagnostic sensor between each of the two thin-walled substrates.

AMG sports exhaust system for a characteristic sound signature

The twin-pipe AMG sports exhaust system has a pipe cross-section of 70 millimetres from the manifolds to the rear silencers. Thanks to a particularly intelligent lightweight design, it has been possible to save 7.6 kg of weight compared with the previous model. The AMG experts achieved this by reducing the wall thickness of all of the exhaust pipes as well as the centre and rear silencers to 1.2 millimetres.

When designing the sound, the aim was to create a perfect synthesis of perceived dynamism and the comfort on long journeys that is the hallmark of a Mercedes. The goal of the developers was to achieve an emotional experience when accelerating and double-declutching, but unobtrusiveness at constant speeds. Unpleasant frequencies or droning noises were eliminated during a series of tests. The sports exhaust system emits a sonorous eight-cylinder sound that is typical of AMG from the chrome twin tailpipes.

Engine production – a tradition of hand-built excellence

Like all other AMG engines, the eight-cylinder biturbo is assembled by hand in the AMG engine shop taken into commission in 2002. Highly-qualified technicians assemble the M 157 according to the “one man, one engine” philosophy, maintaining the very strictest quality standards. This painstaking care is attested to by the responsible engineer’s signature on the characteristic AMG engine plate.

AMG SPEEDSHIFT PLUS 7G-TRONIC with ECO start/stop function

The perfect partner to the AMG 5.5-litre V8 biturbo engine comes in the form of the AMG SPEEDSHIFT PLUS 7G‑TRONIC. The seven-speed automatic transmission distributes the power to all four wheels on a permanent basis and features three modes – Controlled Efficiency (C), Sport (S) and Manual (M) – which can be selected at the push of a button on the centre console. Selecting Controlled Efficiency (“C”) mode activates the ECO start/stop function, which shuts off the eight-cylinder engine when the vehicle comes to a halt. An “ECO” symbol in the AMG main menu indicates the current status to the driver. In “C” mode, the ML 63 AMG generally moves off in second gear. The high engine torque available even at very low engine speeds coupled with the gentle accelerator and transmission characteristics mean that the transmission selects the highest viable gear quickly.

Further efficiency-enhancing measures include:

  • New fuel economy converter with centrifugal pendulum
  • Bearings designed for reduced friction loss
  • Transmission-oil thermal management system

In modes “S” and “M”, the engine and transmission take on a much more agile character, with higher engine speeds, more spontaneous gear changes and faster shift times. The automatic double-declutching function which is now active when downshifting as well as the brief, precisely defined interruption of ignition and injection when shifting up under full load shorten shifting times and increase emotional appeal when adopting a sporty driving style. The seven gears can be changed using the AMG shift paddles on the steering wheel. The upshift indicator integrated into the AMG instrument cluster informs the driver when a manual gear change is advisable.

In the two more performance-oriented driving modes “S” (Sport) and “M” (Manual), the ECO start/stop function is deactivated. If required, the driver can also switch the systems off while in “C” mode by pressing a button on the centre console. In this case an “ECO” symbol will not appear on the instrument cluster either.