Mercedes-Benz has long been synonymous with automotive excellence, and at the heart of this legacy lies the engineering marvel of the Mercedes Engine. From powerful V8s to efficient inline-fours, Mercedes-Benz engines are celebrated for their innovation, performance, and reliability. Continuing this tradition of pushing boundaries, Mercedes-AMG has developed the M 139 engine, a groundbreaking powerplant that redefines what’s possible in a four-cylinder configuration. This engine isn’t just an evolution; it’s a revolution, setting new benchmarks for power density and efficiency in the realm of high-performance engines. Let’s delve into the intricacies of this remarkable Mercedes engine and explore the technologies that make it the world’s most powerful turbocharged four-cylinder in series production.
The M 139: World’s Most Powerful 4-Cylinder Mercedes Engine
The Mercedes-AMG M 139 engine is a testament to engineering prowess, boasting an unprecedented output of up to 416 horsepower. This remarkable figure firmly establishes it as the most potent turbocharged four-cylinder engine currently in series production globally. Mercedes-AMG engineers have not only surpassed their previous benchmark, the M 133 engine, by a significant 40 horsepower but have also elevated the torque, now reaching a maximum of 369 lb-ft from the previous 350 lb-ft. The power-per-liter ratio is equally astonishing, achieving up to 208 hp per liter, outperforming even many engines found in renowned supercars. This compact yet formidable Mercedes engine is meticulously crafted in Affalterbach, Germany, on a state-of-the-art production line, adhering to the revered “One Man, One Engine” principle.
Unrivaled Power and Performance of the Mercedes Engine
Available in two output stages for Mercedes-AMG compact models, the M 139 Mercedes engine offers 416 hp in the S-model variant and 382 hp in its base form. This tiered approach mirrors the successful strategy employed in AMG’s V8-powered Performance models, catering to a broader spectrum of customer preferences and performance needs.
Beyond sheer power figures, this Mercedes engine stands out for its exceptional responsiveness. Engineers meticulously calibrated the torque curve through a process known as “torque shaping.” The result is a peak torque of 369 lb-ft (354 lb-ft for the base version) readily available across a broad rev range of 5000-5250 rpm (4750-5000 rpm for the base version).
This refined configuration allows the M 139 Mercedes engine to deliver power in a manner reminiscent of a naturally aspirated engine, creating a more engaging and emotionally resonant driving experience. Furthermore, the engine developers successfully engineered a dynamically increasing torque curve at lower engine speeds, enhancing agility and responsiveness. The surging torque at higher RPMs encourages spirited driving and highlights the engine’s free-revving nature. The high maximum engine speed, reaching up to 7,200 rpm, definitively positions the M 139 as a true sports car engine within the Mercedes-Benz family.
Alt text: Expert technician meticulously assembling a high-performance Mercedes-AMG M139 engine at the Affalterbach factory, showcasing the “One Man, One Engine” principle.
Tobias Moers, former Chairman of Mercedes-AMG GmbH, aptly stated, “We already set the benchmark in the segment with the preceding engine. This fundamentally new four-cylinder presented us with the challenge of doing even better. And we succeeded with a number of sometimes revolutionary solutions. With the M 139, we have once again impressively demonstrated the engine expertise of Mercedes-AMG. Not only is the output per liter unrivalled for a turbocharged engine, the high level of efficiency also demonstrates that the internal combustion engine still has further potential.”
“One Man, One Engine” Philosophy Reinvented for the Modern Mercedes Engine
The M 139 Mercedes engine is entirely hand-assembled, a testament to Mercedes-AMG’s commitment to craftsmanship and quality. Inside the AMG engine manufactory in Affalterbach, a completely redesigned production line was established to elevate the “One Man, One Engine” principle to new heights, integrating Industry 4.0 methodologies. This advanced approach incorporates the latest innovations in ergonomics, materials handling, quality assurance, sustainability, and efficiency. AMG’s hand assembly operation, in its pursuit of Industry 4.0, embodies the vision of “smart production,” characterized by maximum flexibility, transparency, and exceptional efficiency. This modern production process safeguards and enhances engine quality and production processes through the implementation of innovative digital technologies.
Emmerich Schiller, COO and former member of the Board of Management at Mercedes-AMG GmbH, explained the evolution: “We have completely revised the principle of “One Man, One Engine” for assembly of the M 139. The result is an ultra-modern production process that places the focus on people. To achieve this, we created the ideal working conditions in a bright, precisely organized and clean environment for our employees. This provides the best basis for continuing to ensure our high quality level even as the technology becomes more complex.”
Advanced Engine Technology in the M 139 Mercedes Engine
The M 139 Mercedes engine is packed with intelligent design features that contribute to its exceptional performance and efficiency. One notable aspect is its 180-degree rotation compared to other Mercedes four-cylinder engines.
180-Degree Rotation and Aerodynamic Advantages in Mercedes Engine Design
Unlike the transversely installed M 260 four-cylinder found in “35” models or its predecessor, the M 133 engine, the new Mercedes-AMG M 139 engine is rotated 180 degrees around its vertical axis. This innovative design places the turbocharger and exhaust manifold at the rear, adjacent to the firewall from a rearward perspective, while positioning the intake system at the front. This configuration facilitates a flatter and more aerodynamically optimized front-end design for vehicles housing this powerful Mercedes engine. Moreover, this arrangement optimizes airflow with shorter and less convoluted air ducts for both intake and exhaust systems, enhancing engine breathing and efficiency.
Roller Bearings: Enhancing Turbocharger Responsiveness in Mercedes Engines
The twin-scroll turbocharger within this Mercedes engine is engineered to deliver both rapid responsiveness at lower engine speeds and substantial power at higher RPMs. The turbine housing incorporates two parallel flow passages, working in conjunction with divided ducts in the exhaust manifold to channel exhaust flow to the turbine in a separated manner.
This design minimizes negative interference between cylinders during load cycles and improves the overall gas cycle dynamics. The result is enhanced torque delivery at lower engine speeds and remarkably quick turbocharger response.
Furthermore, a significant advancement in turbocharger technology is the incorporation of roller bearings for the compressor and turbine shafts, a feature shared with the high-output variant of the AMG 4.0-liter V8 engine in the AMG GT 4-door Coupe. Roller bearings minimize mechanical friction within the turbocharger, allowing it to respond more readily and achieve its maximum speed of up to 169,000 rpm with greater rapidity, contributing to the engine’s overall responsiveness and power delivery.
Alt text: Detailed view of key components of the Mercedes-AMG M139 engine, prominently featuring the advanced twin-scroll turbocharger with roller bearings.
Electronic Charge Pressure Control: Optimizing Responsiveness in Mercedes Turbo Engines
The 2.0-liter turbo Mercedes engine achieves a maximum charge pressure of 2.1 bar (1.9 bar in the base version), further highlighting its high-performance nature. An electronically controlled wastegate (exhaust relief valve) enables precise and flexible charge pressure regulation, optimizing responsiveness, particularly during acceleration from partial load conditions. The wastegate control unit considers numerous parameters, including charge pressure, throttle flap position, and knocking tendency. Modifying signals encompass intake air temperature, engine temperature, engine speed, and atmospheric pressure. This sophisticated system also enables temporary charge pressure boosting (overboost) during acceleration, providing an extra surge of power when needed.
To manage heat effectively, fresh air, in addition to oil and water, is employed to cool the turbocharger. Air is directed from the radiator grille specifically to the charger via the engine cover, which is designed as an air deflector, and through ducts positioned beneath the hood. This cooling concept draws upon principles and experience gained from cooling internally mounted turbochargers in current AMG 4.0-liter V8 engines, starting with the AMG GT in 2014. Moreover, the turbine housing incorporates integral insulation for enhanced thermal management.
Crankcase and NANOSLIDE Cylinder Liners: Durability and Efficiency in Mercedes Engine Construction
The Mercedes engine’s all-aluminum crankcase is constructed using a chill-casting process, resulting in exceptional material properties. In this method, molten aluminum is poured into a metallic mold, and the mold’s high thermal conductivity, aided by water cooling, facilitates rapid cooling and solidification of the molten metal. This rapid cooling leads to a fine-grained, dense structure, ensuring very high strength and durability. The chill-casting process also enables the creation of complex interior geometries through the use of enclosed sand cores.
The closed-deck construction, a design principle borrowed from motor racing, provides outstanding rigidity while minimizing weight, and allows for peak combustion pressures reaching up to 160 bar. The areas surrounding the cylinders are largely solid, with only small ducts for coolant and engine oil penetrating the cover plate, maximizing structural integrity. The crank assembly, featuring a lightweight forged steel crankshaft and forged aluminum pistons equipped with optimized piston rings, combines low friction with high strength. The engine’s maximum speed is 7200 rpm, with peak power achieved at 6750 rpm. The sump is equipped with baffle plates to ensure consistent engine oil supply to all critical components, even under high lateral acceleration forces and with a larger sump volume.
To minimize friction between pistons and cylinders, the cylinder liners are treated with patented NANOSLIDE technology. This coating creates a mirror-like surface on the linings, minimizing friction, doubling the hardness compared to conventional grey cast-iron liners, and significantly enhancing durability. NANOSLIDE, developed by Daimler AG, is protected by over 90 patent families and more than 40 patents. First utilized in AMG’s M 156 engine, NANOSLIDE has been employed in numerous subsequent AMG engines for many years and is also found in the Formula 1 engines of Mercedes-AMG Petronas Motorsport, demonstrating its effectiveness in extreme performance applications.
Optimized Cylinder Head and CAMTRONIC Valve Control in Mercedes Engines
Repositioning and slightly angling the injection nozzles and spark plug system within the cylinder head of this Mercedes engine allowed for the enlargement of exhaust valves compared to the preceding M 133 engine. The larger exhaust cross-sections facilitate low-loss gas expulsion from the combustion chambers, reducing overall piston venting action and improving engine efficiency.
Enhanced cylinder head cooling is achieved through the use of seating rings with a reduced installed height and a cooling borehole positioned near the combustion chamber in the web area between the exhaust seating rings. Cooling performance is further improved by a near-surface water jacket geometry, a faster coolant flow rate, and an optimized volumetric flow rate. A multi-layered, state-of-the-art corrugated metal seal isolates the cylinder head from the crankcase, ensuring robust sealing and durability under high pressures and temperatures.
Two overhead camshafts control the 16 valves via weight-optimized roller cam followers. Camshaft adjustment on both the inlet and outlet sides enables excellent engine response and optimizes the gas cycle for various operating conditions. Variable CAMTRONIC valve control on the exhaust side further enhances efficiency and responsiveness, featuring two cams per valve with different geometries. Depending on the cam setting, tailored to driving conditions, exhaust valves can open for shorter or longer durations. This system provides improved responsiveness at low engine speeds, comfortable and fuel-efficient driving at medium rpm, and full power delivery at higher rpm, optimizing engine performance across the entire operating range.
Two-Stage Fuel Injection: Combining Efficiency and Power in the Mercedes Engine
Turbocharging and direct injection with spray-guided combustion are employed in this Mercedes engine to achieve high power output while simultaneously enhancing thermodynamic efficiency, reducing both fuel consumption and exhaust emissions.
Notably, this high-performance four-cylinder Mercedes engine incorporates two-stage fuel injection for the first time. In the first stage, exceptionally fast and precise piezo injectors deliver fuel directly to the combustion chambers at pressures up to 200 bar. This process is often multi-staged and controlled by the engine management system as needed for optimal combustion.
The second stage involves additional intake manifold injection using solenoid valves. This supplementary injection is essential to achieve the engine’s high specific output and ensure sufficient fuel delivery under demanding conditions. The electronically controlled fuel supply operates at a pressure of 6.7 bar, ensuring consistent and reliable fuel delivery across the engine’s operating range.
Sophisticated Cooling System: Managing Heat for Optimal Mercedes Engine Performance
The high output of this Mercedes engine necessitates a meticulously designed cooling system. An auxiliary radiator positioned in the wheel arch complements the primary radiator in the front module, enhancing overall cooling capacity. A low-temperature circuit is also integrated for air-to-water intercooling. Working in conjunction with a series-connected intercooler, a high-performance electric pump assists coolant flow through the radiators. This comprehensive cooling system ensures optimal cooling of the highly compressed charge air, contributing to peak engine performance and preventing overheating under strenuous conditions.
Transmission oil cooling is integrated into the engine’s coolant circuit and is further supported by a heat exchanger directly mounted on the transmission. The engine control unit is strategically located on the air filter housing, where it benefits from airflow cooling, maintaining optimal operating temperatures for electronic components.
Electric Water Pump: Enhancing Efficiency and Control in Mercedes Engine Cooling
The demand-controlled, electric high-performance water pump operates independently of engine speed, offering significant advantages. Delayed activation during engine warm-up allows the engine block to reach operating temperature more quickly, reducing friction and improving fuel consumption and emissions. The pump can also be selectively activated or deactivated based on driving demands, reducing parasitic losses when less cooling is required at lower power outputs or engine speeds. Furthermore, the electric water pump ensures full engine output and optimal heat dissipation across the entire engine speed range and provides protection against thermal damage when idling in high ambient temperatures, ensuring consistent and reliable engine cooling under diverse operating conditions.
Additional features incorporated into this advanced Mercedes engine technology package include alternator management, the ECO start/stop function with rapid restarting, a gliding function for enhanced fuel efficiency, and a gasoline particulate filter to minimize emissions.
Sustainable and Efficient Production of the Mercedes Engine
The new AMG 2.0-liter turbocharged four-cylinder Mercedes engine, internally designated M 139, is assembled entirely by hand following the traditional AMG “One Man, One Engine” principle. However, the production process has been revolutionized with digital support and optimized logistical organization.
Industry 4.0 and Smart Production for Mercedes-AMG Engines
People remain central to the production process, with employees assisted by digital tools. The focus is on leveraging intelligent, flexible technology to enhance efficiency and ergonomics. The cornerstone of this modern production process is a combination of highly flexible line assembly and pre-configured shopping carts utilizing driverless transport systems. Sustainability was a key consideration in the planning of the new M 139 production line. Production operations utilize renewable energy sources and significantly reduce CO2 emissions, water consumption, and waste, reflecting Mercedes-AMG’s commitment to environmentally responsible manufacturing.
Ergonomic Assembly Carts and Digital Tools for Mercedes Engine Craftsmanship
The assembly cart used for building the M 139 Mercedes engine was collaboratively developed with the assembly employees. It features its own independent power supply, eliminating the need for power cables and enhancing workplace safety and flexibility. All necessary operating fluids and tools are ergonomically positioned on and around the cart, streamlining workflows, minimizing movement, and improving overall efficiency. An integrated tablet PC provides employees with precise, clearly presented work instructions, eliminating paper-based manuals and guidelines and creating a paperless manufacturing environment.
Alt text: Modern Mercedes-AMG engine assembly line in Affalterbach, showcasing digital tools and ergonomic workstations used in the “One Man, One Engine” production process.
The new cordless screwdrivers are readily accessible, eliminating the need to retrieve suspended, wired tools from overhead at each station. This improved ergonomics has led employees to affectionately call their workplace “blue sky,” as the absence of hanging power cables creates a more open and pleasant working environment. The assembly shop is designed to be bright and airy, fostering a comfortable and productive working climate. Comprehensive digitization enhances both the efficiency and flexibility of the manufacturing process. Each tool is connected to the engine assembly shop’s WLAN, enabling automated enabling and torque settings for each assembly stage via indoor tracking. Furthermore, all completed tasks are digitally recorded, ensuring optimal quality assurance, traceability, and transparency throughout the engine assembly process.
Driverless Transport Systems: Streamlining Mercedes Engine Component Delivery
Each assembly technician is accompanied by a driverless transport system. These automated systems carry shopping carts precisely loaded with the components required for the engine being assembled at that specific station. The transport systems are loaded at the Mercedes-AMG logistical center in Marbach and delivered to the production line on a “just-in-sequence” basis, optimizing inventory management and reducing material handling. Indoor tracking via WLAN enables autonomous control of these transport systems, and all components are digitally tracked throughout the assembly process, ensuring accurate and efficient material flow.
The assembly and transport carts are styled in a black-and-white Mercedes-AMG design and feature motivational slogans such as “START YOUR ENGINE” or “AMG PERFORMANCE INSIDE,” fostering employee motivation and brand identification. Similarly, the shop floor incorporates design elements reminiscent of racetracks, including hatching and white-and-red stripes, reinforcing the performance-oriented nature of Mercedes-AMG.
Enhanced Test Stations: Ensuring Mercedes Engine Quality and Efficiency
Assembly efficiency is further enhanced by reducing the number of test stations through the consolidation of several individual stations into three central stations. These stations perform drag torque tests, leakage tests for oil, coolant, and fuel systems, and tests of the complete engine water jacket. This consolidation results in significant time savings and increased overall efficiency in the testing process. Here, too, all parameters and measured values are digitally recorded and stored, enabling complete traceability of the assembly process for each individual Mercedes engine and guaranteeing consistent quality control.
The “One Man, One Engine” assembly philosophy remains a hallmark of the Mercedes-AMG brand. Consequently, the M 139 Mercedes engine proudly features the AMG engine plate bearing the signature of the responsible assembly technician, signifying individual craftsmanship and accountability. All assembly technicians involved in the production of the new four-cylinder engine underwent extensive specialized training for the M 139, ensuring the highest levels of expertise and quality in the assembly of this advanced Mercedes engine.
Technical Data at a Glance
| Mercedes-AMG M 139 2.0 liter turbocharged four-cylinder engine | |
|---|---|
| Displacement | 1991 cc |
| Bore x stroke | 83.0 x 92.0 mm |
| Output | 416 hp at 6750 rpm (S-model) 382 hp at 6500 rpm (base version) |
| Peak torque | 369 lb-ft at 5000-5250 rpm (S-model) 354 lb-ft at 4750-5000 rpm (base version) |
| Max. engine speed | 7200 rpm |
| Compression ratio | 9.0:1 |
| Turbocharging | One twinscroll turbocharger with roller-bearing compressor and turbine wheels |
| Max. charge pressure | 2.1 bar (S-model) 1.9 bar (base version) |
| Mixture formation | Combined direct and manifold injection. 1.) Third-generation multiple direct injection. Fast and precise piezo injectors spray the fuel into the combustion chambers at high pressure 2.) Additional intake manifold injection with solenoid valves |
| Cylinder head | Two overhead camshafts, 16 valves, adjustable intake and exhaust camshafts, CAMTRONIC valve timing adjustment for the exhaust camshaft |
| Max. air mass throughput | 2,645 lb/h (S-model) 2,425 lb/h (base version) |
| Engine weight (wet) | 353.8 lbs |
