Ενώ μέχρι τώρα υποθέταμε ότι η ανανεωμένη Mercedes-Benz S-Class θα εξοπλίζεται με τους ίδιους κινητήρες, η Γερμανική εταιρία ανακοίνωσε σήμερα ότι το 2017 θα εντάξει 4 νέα σύνολα στην γκάμα της: εξακύλινδρους εν σειρά κινητήρες βενζίνης και πετρελαίου, έναν νέο τετρακύλινδρο βενζινοκινητήρα και έναν νέο, biturbo V8. Οι κινητήρες αυτοί είναι μέρος μίας επένδυσης 3 δισεκατομμυρίων ευρώ από την Mercedes-Benz και σύμφωνα με την εταιρία “θέτουν νέα standards όσον αφορά στην ισχύ, τον εξευγενισμό και την αποδοτικότητα” ενώ παράλληλα ανοίγουν νέους δρόμους όσον αφορά στο modularity, υιοθετώντας ενιαία απόσταση μεταξύ κυλίνδρων της τάξης των 90 χιλιοστών και πανομοιότυπες διασυνδέσεις με το αυτοκίνητο.

Ξεκινάμε από τον κινητήρα με τον μικρότερο αριθμό κυλίνδρων. Ο δίλιτρο, τετρακύλινδρος βενζινοκινητήρας με κωδικό M264 εξοπλίζεται μεταξύ άλλων με twin-scroll turbo, βελτιωμένη πολλαπλή εισαγωγής και αντλία νερού που τροφοδοτείται από ένα ηλεκτρικό σύστημα 48 volt. Το αποτέλεσμα όλων αυτών, είναι ειδική απόδοση της τάξης των 134 ίππων ανά λίτρο ενώ η Merc τονίζει ότι η άνεση και το NVH του κινητήρα ήταν πολύ ψηλά στην λίστα προτεραιοτήτων των μηχανικών!

Στη συνέχεια, έχουμε τους εξακύλινδρους εν σειρά – με κωδικούς M256 για τον βενζινοκινητήρα και OM656 για τον diesel. Όσον αφορά στον OM656, η Mercedes μας λέει ότι ενώ είναι σημαντικά ισχυρότερος –πάνω από 313 άλογα και πάνω από 650 Nm ροπής– από τον V6, χάρη στην “stepped-bowl” καύση και την βελτιωμένη Nanoslide επίστρωση κυλίνδρων, καταναλώνει τουλάχιστον 7% λιγότερο καύσιμο. Από την άλλη, ο M256 είναι ένας κινητήρας που σχεδιάστηκε από την αρχή για “συστηματική ηλεκτροποίηση”. Εξοπλίζεται με ηλεκτρικό σύστημα 48 volt που χρησιμοποιείται όχι μόνο  για την τροφοδοσία της αντλίας νερού και τον κομπρέσσορα του air-condition, αλλά και για τον Integrated Starter-Generator (ISG) με αποτέλεσμα να μην υπάρχουν ιμάντες για τα περιφερειακά εξαρτήματα και να μειώνεται το μήκος του κινητήρα – και η φυσική πολυπλοκότητα του εννοείται. Επιπλέον, ο ISG προσφέρει και υβριδικές λειτουργίες, όντας ικανός για boost 20 ίππων/220 Nm ροπής, ανάκτηση ενέργειας κλπ. Έτσι, ο τρίλιτρος, εξακύλινδρος εν σειρά είναι σε θέση να αποδίδει περισσότερα από 408 άλογα και περισσότερα από 500 Nm ροπής ενώ οι εκπομπές CO2 έχουν μειωθεί κατά περίπου 15%!

Τέλος, έχουμε τον  M176 biturbo V8. Ο τετράλιτρος βενζινοκινητήρας έχει εξελιχθεί από την AMG και ενώ δεν υπάρχουν ακριβή νούμερα, οι Γερμανοί μας λένε ότι αποδίδει περισσότερα από 476 άλογα με την ροπή να είναι στα 700 Nm περίπου από τις 2.000 σ.α.λ. Ενώ είναι ικανός για αυτά τα νούμερα, ο νέος V8 είναι κατά 10% πιο οικονομικός όσον αφορά στην κατανάλωση καυσίμου σε σύγκριση με τον προκάτοχο του! Για ακόμα χαμηλότερη κατανάλωση, αν ο οδηγός έχει επιλέξει είτε το Comfort πρόγραμμα, είτε το Economy, σε συνθήκες μερικού φορτίου και μεταξύ 900 και 3.250 σ.α.λ., ο M176 απενεργοποιεί τους μισούς κυλίνδρους (συγκεκριμένα τους 2, 3, 5 και 8). Φυσικά, τα δύο turbos είναι τοποθετημένα στο εσωτερικό του V ενώ αξίζει να αναφέρουμε ότι ο κινητήρας διαθέτει την Nanoslide επίστρωση κυλίνδρων.

Όπως αναφέρει η Mercedes-Benz, η νέα S-Class θα είναι το πρώτο μοντέλο που θα εξοπλιστεί με αυτούς τους κινητήρες ωστόσο περιμένουμε στη συνέχεια να ακολουθήσουν και τα υπόλοιπα μοντέλα της Γερμανικής εταιρίας.

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Extensive strategic engine initiative from Mercedes-Benz: More powerful, more economical and cleaner

Stuttgart/Sindelfingen. The biggest strategic engine initiative in the history of Mercedes-Benz will enter its decisive phase in 2017. Following the launch of the new four-cylinder diesel engine in spring 2016, next year will see the addition of no fewer than four more members to the all-new family of engines: six-cylinder in-line engines in both diesel and petrol versions, a new four-cylinder petrol engine and a new biturbo V8. At the same time, there will be world premieres for ground-breaking technologies, such as the Integrated Starter-Alternator (ISG), the 48 V electrical system and the electric auxiliary compressor (eZV). These new technologies are tuned to the vehicles on state-of-the-art test rigs at the equally new Powertrain Integration Centre (AIZ) in Sindelfingen.

“More powerful, more economical and cleaner – the new modular family of engines from Mercedes-Benz offers the right powertrain for every vehicle,” says Prof. Dr Thomas Weber, 62, Member of the Daimler Board of Management with responsibility for Group Research at Daimler AG and Mercedes-Benz Cars Development. “The systematic optimisation of our high-tech engines plays a crucial role in the road map towards sustainable mobility. They also need to be designed with a view to all current and future requirements. A key success factor in this regard is the extensive electrification of the powertrain.”

Systematic electrification: new six-cylinder in-line petrol engine M 256

The new six-cylinder in-line petrol engine M 256 represents an outstanding example of electrification, including a 48 V electrical system. New, intelligent turbocharging, e.g. with an electric auxiliary compressor (eZV), as well as an Integrated Starter-Alternator (ISG) provide the guarantee of excellent drivability with no turbo lag. The ISG is responsible for hybrid functions, such as boost or energy recovery, while allowing fuel savings that were previously reserved for high-voltage hybrid technology. The bottom line is that the new six-cylinder in-line engine offers the same performance as an eight-cylinder machine while being much more fuel-efficient. The new petrol engine (internal code: M 256) launches next year in the new S-Class.

Systematic electrification dispenses with the need for a belt drive for ancillary components at the front of the engine, which reduces its overall length. The narrow construction, together with the physical separation of intake/exhaust, creates space for near-engine exhaust aftertreatment. The 48 V electrical system serves not only high power consumers, such as the water pump and air-conditioning compressor, but also the Integrated Starter-Alternator (ISG), which also supplies energy to the battery by means of highly efficient energy recovery.

An additional bonus is the unsurpassed refinement of the six-cylinder in-line engine. Output and torque are similar to the current eight-cylinder engine, i.e. over 300 kW (408 hp) and more than 500 Nm. In comparison with the previous V6, the CO₂ emissions from the engine have been reduced by around 15 percent.

At 500 cc, the new machine has the same displacement per cylinder as the premium diesel engine family unveiled last year as well as the family of four-cylinder petrol engines.

Most powerful passenger-car diesel engine in the history of Mercedes-Benz: six-cylinder OM 656

The new top-of-the-line engine in the premium diesel family is likewise a six-cylinder in-line machine. The characteristics of the OM 656 include the stepped-bowl combustion process, two-stage exhaust turbocharging and, for the first time, the use of CAMTRONIC variable valve timing. Its design features a combination of aluminium engine block and steel pistons as well as further-improved NANOSLIDE^® coating of the cylinder walls. Although there is a significant increase in output compared with the previous OM 642 (over 230 kW/313 hp instead of 190 kW/258 hp), the new engine consumes more than seven percent less fuel.

Like the already unveiled four-cylinder OM654, the new six-cylinder diesel engine OM 656 is likewise designed to comply with future emissions legislation (RDE – Real Driving Emissions). All the components of relevance for efficient emissions reduction are installed directly on the engine. The integrated technology approach of new stepped-bowl combustion process, dynamic multi-way exhaust gas recirculation and near-engine exhaust aftertreatment, combined for the first time with variable valve timing, opens the way for further reductions in consumption together with extremely low emissions. Thanks to the near-engine insulated configuration, exhaust aftertreatment has a low heat loss and extremely favourable operating conditions. This is reinforced by the CAMTRONIC switchable exhaust camshaft, which supports the consumption-neutral heating of the exhaust system.

Number of cylinders to suit the requirements: new V8 biturbo petrol engine M 176

Dynamic power delivery combined with high efficiency: the new biturbo (internal code: M 176) is one of the most economical V8 petrol engines in the world. Its special features include cylinder shutoff at part load as well as the positioning of the turbochargers in the V between the cylinder banks. From its 3982 cc displacement, the new V8 biturbo produces over 350 kW (476 hp) with a maximum torque of around 700 Nm from 2000 rpm. The new engine will consume over 10 percent less fuel than its predecessor, which is rated at 335 kW (455 hp). The new V8 will launch with this technology next year in the new S-Class.

For lower fuel consumption, when operated at part load the new M 176 shuts off four cylinders simultaneously by means of CAMTRONIC valve timing. This reduces the pumping losses while improving the overall efficiency of the remaining four cylinders by shifting the operating point towards higher loads.

Sporty specific output: new four-cylinder petrol engine M 264

A two-litre four-cylinder engine with a specific output of around 100 kW: the new Toptype petrol engine from Mercedes-Benz (internal code: M 264) advances into output regions previously reserved for high-displacement six-cylinder machines. At the same time, it consumes significantly less fuel than a comparable six-cylinder engine. The engine’s special features include twin-scroll turbochargers, belt-driven 48 V starter-alternator (BSA) and electric 48 V water pump.

The BSA is also responsible for fuel-saving hybrid functions:

• Easy start: virtually imperceptible starting and acceleration of the engine
• Boost in the engine-speed range up to 2500 rpm
• Energy recovery up to 12.5 kW
• Shifting of the load point: allows operation in a more favourable area of the engine map
• Coasting with engine off.

In the interests of high power output and a spontaneous engine response, Mercedes-Benz has opted for twin-scroll turbocharging. Unlike conventional systems, a twin-scroll turbocharger merges the exhaust gas ducts of cylinder pairs in the flow-optimised manifold. This turbocharging concept with systematic cylinder flow separation produces high torque in the low-rpm range together with high specific output. Further efficiency measures include intake CAMTRONIC and a friction loss reduction package.

Even cleaner: particulate filter for petrol engines as standard

Mercedes-Benz is the first manufacturer to opt for the large-scale use of particulate filters for petrol engines to further improve their environmental compatibility. After more than two years of positive experience in the field with the S 500, in 2017 further S-Class variants will be equipped with the new M 256 and M 176 petrol engines with this technology. The filter will then be gradually introduced in other new vehicle models, facelifted models and new engine generations, such as the M 264.

The particulate filter for petrol engines reduces the emissions of fine soot particles. How it works: the exhaust-gas stream is supplied to a particulate filter system. The filter has a honeycomb structure with alternately sealed inlet and outlet channels. This forces the exhaust gas to flow through a porous filter wall, which traps the soot. The filter can be continuously regenerated under corresponding driving conditions.

New Powertrain Integration Centre (AIZ): state-of-the-art test rigs

With its new Powertrain Integration Centre (AIZ), in summer 2016 Mercedes-Benz took into service one of the automotive industry’s most advanced test facilities. A total of ten vehicle test rigs inside the all-new state-of-the-art building in Sindelfingen are used for such purposes as the fine tuning of engine and transmission – comfort, dynamics and agility are matched to each other. The highlights include test rigs with high-precision torque measurement directly at the wheels of the vehicle as well as a test rig with a climatic altitude chamber, which uses partial vacuum to simulate an altitude of up to 5000 metres at temperatures of down to -30°C, while the vehicle operates fully automatically on a chassis dynamometer.

The new building at the Sindelfingen Mercedes-Benz Technology Centre (MTC) houses ten vehicle test rigs for tuning vehicles and their powertrains. The new building used 16,800 m³ of concrete, equivalent to the capacity of five Olympic swimming pools. There were also 2500 tonnes of reinforcing steel. The designers of the AIZ attached great importance to energy recovery, with 98 percent of the electric braking energy produced on the test rigs being fed back into the power network. Also, the air conditioning of the test rigs is energy-neutral for two-thirds of the year, which means that no power is consumed from the joint network. With all ten test rigs in continuous operation, this would be the same as supplying around 7500 households with electricity.

Extension of the Mercedes-Benz Technology Centre

The new Powertrain Integration Centre is part of extensive additions and conversions to the Mercedes-Benz Technology Centre (MTC) in Sindelfingen. The new driving simulator, climatic wind tunnels and a high-tech aero-acoustic wind tunnel are already in operation. By 2018, there will also be a state-of-the-art technology centre for vehicle safety, an electronics testing centre and a computer centre. Housed on the upper floor of the AIZ, the computer centre will directly use the electricity generated downstairs on the test rigs in order to operate and cool the computers.

The MTC is home to the headquarters of the company’s global Group Research and passenger car development, including design.

New four-cylinder petrol engine (M 264): Specific output and agility on a par with a sports car

A two-litre four-cylinder engine with a specific output of up to 100 kW: the new Toptype petrol engine from Mercedes-Benz (internal code: M 264) advances into output regions previously reserved for high-displacement six-cylinder machines. At the same time, it consumes significantly less fuel than a comparable six-cylinder engine. The engine’s special features include twin-scroll turbochargers and belt-driven 48 V starter-alternator (BSA). The M 264 will celebrate its debut next year.

A specific output of around 100 kW per litre almost puts the M 264 on a par with full-blooded sports car engines. In the interests of high power output and spontaneous engine response, Mercedes-Benz has opted for twin-scroll turbocharging, as in the Mercedes-AMG M 133 engine. Unlike conventional systems, a twin-scroll turbocharger merges the exhaust gas ducts of cylinder pairs in the flow-optimised manifold. This turbocharging concept with systematic cylinder flow separation produces high torque in the low-rpm range together with high specific output.

A further-improved intake manifold with extremely short air paths and an exceptionally compact compressor housing additionally ensure spontaneous engine response and fast reactions to accelerator pedal movements. The twin-scroll turbocharger has an electric wastegate actuator, which allows fast changes of the charge-air pressure.

Further efficiency measures include intake CAMTRONIC, a newly developed electric 48 V water pump and a friction loss reduction package.

The M 264 is combined with a 48 V electrical system, which is used for the belt-driven starter-alternator (BSA) and the electric water pump. The BSA is also responsible for fuel-saving hybrid functions:

• Easy start: virtually imperceptible starting and acceleration of the engine
• Boost in the engine-speed range up to 2500 rpm
• Energy recovery up to 12.5 kW
• Shifting of the load point: the engine can be operated in a more favourable area of the engine map; load increase/reduction depending on the state of charge of the battery
• Coasting with engine off

• iECO: extended stop/start with intelligent engine shutoff even at low speeds

At the very top of the list of requirements for developers were comfort and NVH (noise, vibration, harshness). Plastic engine mounts and the BSA contribute to exemplary refinement, as do numerous insulation measures. These include insulation of the engine block and extensive covering of the engine with an acoustic insert as well as further NVH optimisation in relation to the injection hydraulics. To guarantee excellent exhaust emissions, use is made of tried-and-tested piezo injectors with good mixture preparation, a further-improved combustion chamber and a particulate filter for petrol engines.

New six-cylinder diesel engine (OM 656): Majestic long-distance athlete

With the new six-cylinder in-line diesel engine OM 656, the next member of the ground-breaking family of premium diesel engines from Mercedes-Benz will follow in 2017. Its features include the stepped-bowl combustion process, a combination of aluminium engine block and steel pistons as well as further-improved NANOSLIDE^® cylinder wall coating.

The new family of premium diesel engines from Mercedes-Benz celebrated its world premiere with the four-cylinder E 220 d in spring 2016. In 2017, another important representative of this modular family will follow with the six-cylinder in-line engine OM 656. Although there is a significant increase in output compared with the previous OM 642 (over 230 kW/313 hp instead of 190 kW/258 hp), the new engine consumes more than seven percent less fuel.

A special feature of the family of premium diesel engines is the combination of steel pistons with an all-aluminium engine block. The lower expansion of steel as operating temperatures rise ensures an increasing clearance between piston and aluminium block, thereby reducing the friction by 40 to 50 percent. At the same time, the fact that steel is stronger than aluminium allows very compact, lightweight pistons that even offer additional strength reserves. Finally, the lower thermal conductivity of steel leads to higher component temperatures, thereby improving the thermodynamic efficiency, increasing combustibility and reducing combustion duration.

The combination of innovative steel pistons and the optimised piston ring package with the further-improved NANOSLIDE^® coating of the cylinder walls results in benefits in terms of fuel consumption and CO₂ emissions, especially in the lower and medium engine-speed ranges, which are of relevance for day-to-day vehicle use.

Stepped-bowl combustion process

The new OM 656, too, employs the Mercedes-Benz stepped-bowl combustion process – named after the shape of the combustion bowl in the piston. The stepped bowl has a positive effect on the combustion process, the thermal loading of critical areas of the pistons and the introduction of soot into the engine oil. The efficiency is increased by the higher burning rate in comparison with the previous omega combustion bowl. The characteristic feature of the specifically configured combination of bowl shape, air movement and injector is its very efficient utilisation of air, which allows operation with very high air surplus. This means that particulate emissions can be reduced to an especially low level.

Exhaust emissions: all set for the future

The new diesel engine is designed to meet future emissions legislation (RDE – Real Driving Emissions). All the components of relevance for efficient emissions reduction are installed directly on the engine. Supported by insulation measures and improved catalyst coatings, there is no need for engine temperature management during cold starting or at low load. In addition to the advantages in terms of emissions, this results in fuel savings, especially on short journeys. Thanks to the near-engine configuration, exhaust aftertreatment has a low heat loss and extremely favourable operating conditions. This is reinforced by the CAMTRONIC switchable exhaust camshaft, which supports the consumption-neutral heating of the exhaust system.

The new engine is equipped with multi-way exhaust gas recirculation (EGR). It combines cooled high-pressure and low-pressure EGR. This makes it possible to significantly further reduce the untreated emissions from the engine across the entire engine map, with the centre of combustion being favourable for fuel economy.

The data of the new engine in comparison with its predecessor:

New six-cylinder petrol engine (M 256): Fascinating 48 V drive

Mercedes-Benz has developed a new six-cylinder in-line petrol engine that has for the first time been systematically designed for electrification. New, intelligent turbocharging, e.g. with an electric auxiliary compressor (eZV), as well as an Integrated Starter-Alternator (ISG) provide the guarantee of excellent drivability with no turbo lag. ISG is responsible for hybrid functions, such as boost or energy recovery, while allowing fuel savings that were previously reserved for high-voltage hybrid technology. The bottom line is that the new six-cylinder in-line engine offers the same performance as an eight-cylinder machine while being much more fuel-efficient. The new petrol engine (internal code: M 256) launches next year in the new S-Class.

The six-cylinder in-line engine features systematic electrification. For example, there is no belt drive for ancillary components at the front of the engine, which reduces its overall length. The narrow construction, together with the physical separation of intake/exhaust, creates space for near-engine exhaust aftertreatment. At 500 cc, the new engine has the same displacement per cylinder as the premium diesel engine family unveiled last year as well as the family of four-cylinder petrol engines. An additional bonus is the unsurpassed refinement of the six-cylinder in-line engine.

The output and torque of the new six-cylinder in-line engine are similar to the current eight-cylinder machine, i.e. over 300 kW (408 hp) and more than 500 Nm. In comparison with the previous V6, the CO₂ emissions from the engine have been reduced by around 15 percent.

Its performance is as dynamic as that of a V8, as the new six-cylinder in-line engine comes with an especially intelligent form of turbocharging: assisted by the ISG at start-off, the electric auxiliary compressor (eZV) guarantees immediate high torque when driving off and accelerating, bridging the time before the large exhaust turbocharger cuts in. The electric turbocharger accelerates to 70,000 rpm within 300 milliseconds, ensuring an extremely spontaneous reaction from the engine. The result is a dynamic engine response with no turbo lag.

The M 256 is the first member of a new family of premium petrol engines that have for the first time been systematically designed for electrification from the outset. The 48 V electrical system serves not only high power consumers, such as the water pump and air-conditioning compressor, but also the Integrated Starter-Alternator (ISG), which also supplies energy to the battery by means of highly efficient energy recovery. The ISG dispenses with the need for a belt drive for these components. This not only reduces the overall length of the engine and its complexity, but also paves the way for new, efficient control possibilities. The still existing 12 V system supplies power to consumers such as lights, cockpit, infotainment and control units.

The ISG is a key component of the 48 V system and not only serves as an alternator, but is also responsible for hybrid functions. This allows fuel savings that were previously reserved for high-voltage hybrid technology. For the first time, the ISG is also responsible for idle speed control. The hybrid functions include:

• Boost: 15 kW/220 N
• Energy recovery
• Shifting of the load point: the engine can be operated in a more favourable area of the engine map; load increase/reduction depending on the state of charge of the battery
• Coasting
• 3S start: almost imperceptible reinstatement of the engine

Another feature of the new family of premium petrol engines is near-engine exhaust aftertreatment. The as-standard particulate filter is the only part of the exhaust system that is under the floor. The M 256 is produced at the Untertürkheim plant.

The data of the new engine in comparison with its predecessor:

New V8 biturbo petrol engine (M 176): Number of cylinders to suit the requirements

Dynamic power delivery combined with high efficiency: the new biturbo is one of the most economical V8 petrol engines in the world. The special features of the V8 (internal code: M 176) include cylinder shutoff at part load. The M 176 will launch with this technology next year in the new S-Class.

Developed by AMG for Mercedes-Benz, the hallmarks of the new V8 biturbo are exemplary efficiency and environmental compatibility as well as superlative performance. From its 3982 cc displacement, the new V8 biturbo produces over 350 kW (476 hp) with a maximum torque of around 700 Nm from 2000 rpm. The new engine will consume over 10 percent less fuel than its predecessor, which is rated at 335 kW (455 hp).

For even lower fuel consumption, when operated at part load the new M 176 shuts off four cylinders simultaneously by means of CAMTRONIC valve timing. This reduces the pumping losses while improving the overall efficiency of the remaining four cylinders by shifting the operating point towards higher loads.

The cylinders are turned on and off by the interplay between engine control and actuators on the cylinder head. The switchover to four-cylinder operation is accomplished by eight actuators that act on the axially movable cam parts of the intake and exhaust camshafts via a selector. These cam parts are held on the carrier shaft by gears and are locked in the respective end positions by means of a locking mechanism. The intake and exhaust valves of cylinders 2, 3, 5 and 8 do not open due to the zero-lift cams of the cam parts. At the same time, the fuel supply and ignition are deactivated, so that no unburned mixture is left in the deactivated combustion chamber.

Cylinder shutoff is active in the engine-speed range between 900 and 3250 rpm, provided the driver has selected mode C or E with the DYNAMIC SELECT switch. Cylinder shutoff is inactive in all other transmission modes. As soon as the driver requests higher engine power via the position of the accelerator or as soon as the engine speed goes above 3250 rpm, cylinders 2, 3, 5 and 8 are reinstated within a matter of milliseconds. The transition between the two operating modes is seamless and with no loss of comfort for the occupants. The main menu in the instrument cluster shows whether the engine is currently in four- or eight-cylinder mode.

The new V8 biturbo employs a centrifugal pendulum to reduce both the fourth-order vibrations in eight-cylinder mode as well as the second-order vibrations in four-cylinder mode.

A combination of biturbocharging and direct petrol injection with spray-guided combustion increases the thermodynamic efficiency, thereby reducing the fuel consumption and exhaust emissions. Particularly fast and precise piezo injectors spray the fuel at high pressure into the eight combustion chambers. Multiple injection occurs on-demand, ensuring a homogeneous fuel/air mixture. The delivery of fuel is electronically controlled and fully variable for a fuel pressure between 100 and 200 bar.

The engine is of closed-deck construction, which means that the engine block cover plate is extensively closed in the area around the cylinders. The engine block is of an aluminium alloy and produced by permanent mould casting. This ensures extreme strength while keeping the weight as low as possible, and allows high injection pressures of up to 140 bar. The further-improved NANOSLIDE^® coating of the cylinder liners reduces the friction loss while contributing to excellent efficiency. The cylinder head uses an aluminium-zirconium alloy, which is a better conductor of heat than the standard aluminium alloy.

“Spectacle honing” is another measure for reducing the friction and therefore consumption: in this complex process, the cylinder liners receive their mechanical surface treatment when already bolted in place. A jig resembling spectacles is bolted to the engine block in place of the cylinder head, which is mounted later. The honing of the engine block already produces the same state of stress as when the cylinder heads are mounted. For this reason, the tension of the piston rings can be reduced, which leads to a further reduction in friction loss and lower oil consumption.

For an exceptional engine response and low exhaust emissions, the two turbochargers are positioned not on the outside of the cylinder banks, but between them in the “V” – experts call this the “hot inside V”. In the interests of thermal protection for the engine components, the manifolds and exhaust turbochargers are specially insulated.

The efficiency-raising measures include the low-friction drive of alternator and refrigerant compressor by means of two short four-groove belts. The water pump is chain-driven by the timing assembly. A two-stage feedback-controlled oil pump circulates the engine oil. It varies the flow rate depending on the required load and engine speed, thereby helping to save fuel.

The M 176 has exhaust aftertreatment with two catalysts directly mounted on the engine and on the underfloor. The as-standard particulate filter is part of the exhaust system under the floor.

The M 176 is produced at the Untertürkheim plant in Stuttgart.

The data of the new engine in comparison with its predecessor:

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