Affalterbach has once again redefined engine technology with the groundbreaking Mercedes-AMG 2.0-liter M 139 engine. This completely new development emerges as the world’s most potent turbocharged four-cylinder engine in series production, delivering an astonishing output of up to 416 hp. Mercedes-AMG has surpassed its own previous benchmark, the M 133 engine, by an impressive 40 hp, while also boosting maximum torque from 350 to up to 369 lb-ft. Boasting a per-liter output of up to 208 hp, this high-performance turbo engine outclasses many renowned supercar engines, showcasing the pinnacle of modern engine engineering. The meticulously crafted engine is assembled in Affalterbach on an innovative production line adhering to the revered “One Man, One Engine” principle.
Unleashing Unprecedented Power from a Mercedes 4 Cylinder Engine
The Mercedes-AMG M 139 engine is specifically tailored for the compact models within the Mercedes-AMG range and is offered in two performance stages to cater to diverse customer preferences. The S-model variant boasts a formidable 416 hp, while the base version delivers a still-impressive 382 hp. This strategic product segmentation mirrors the successful approach implemented in AMG’s V8-powered Performance models, ensuring that customer desires for varying levels of power are precisely met.
Beyond sheer power figures, the M 139 stands out for its exceptional responsiveness. AMG engineers have meticulously sculpted the torque curve through a process termed “torque shaping.” This careful calibration ensures that the peak torque of 369 lb-ft (354 lb-ft for the base version) is readily available across a broad rev range, specifically from 5000 to 5250 rpm (4750-5000 rpm in the base version).
This deliberate engine configuration results in a power delivery profile akin to that of a naturally aspirated engine, enriching the driving experience with a more visceral and engaging feel. Engine developers have also successfully engineered a dynamically ascending torque curve in the lower engine speed spectrum, significantly enhancing agility and responsiveness during acceleration. The progressive torque build-up as revs climb further contributes to the engine’s free-revving character. Furthermore, the engine’s high maximum engine speed limit of 7200 rpm unequivocally positions the M 139 as a true sports engine, ready for high-performance demands.
Tobias Moers, Chairman of Mercedes-AMG GmbH at the time of the engine’s release, 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.”
Reimagining “One Man, One Engine” for the Modern Era
The Mercedes-AMG M 139 engine epitomizes handcrafted precision, being entirely assembled by hand. Within the AMG engine manufactory in Affalterbach, a newly designed production line on the first floor represents a significant evolution of the “One Man, One Engine” principle. This modern facility seamlessly integrates Industry 4.0 methodologies, incorporating the latest advancements in ergonomics, materials handling, quality assurance, sustainability, and overall efficiency. AMG’s hand assembly operation, in its pursuit of Industry 4.0 implementation, embodies the vision of “smart production”—characterized by maximum flexibility, transparency, and exceptional efficiency. Innovative digital technologies are employed to safeguard and continuously improve both engine quality and production processes.
Emmerich Schiller, COO and member of the Board of Management at Mercedes-AMG GmbH, explained, “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.”
The 180-Degree Rotation Advantage in Mercedes 4 Cylinder Engine Design
The innovative design of the Mercedes-AMG M 139 engine incorporates numerous intelligent features. A key differentiator from the transversely installed M 260 four-cylinder found in the “35” models and the preceding M 133 engine is the M 139’s 180-degree rotation around its vertical axis. This rotation strategically positions the turbocharger and exhaust manifold at the rear, towards the firewall, while placing the intake system at the front.
This configuration yields several significant benefits. Firstly, it facilitates a flatter and more aerodynamically optimized front-end design for the vehicle. Secondly, the reversed arrangement streamlines airflow with shorter and less convoluted air ducts for both intake and exhaust systems, enhancing engine breathing and efficiency.
Roller Bearings and Turbocharger Responsiveness
The new twin-scroll turbocharger integrated into the Mercedes 4 Cylinder Engine M 139 is engineered to deliver both rapid response at lower engine speeds and substantial power at higher rpm. The turbine housing features dual flow passages running parallel to each other. Combined with divided ducts in the exhaust manifold, this design allows exhaust gases to be channeled to the turbine separately.
Alt text: Close-up of the twin-scroll turbocharger in the Mercedes-AMG M139 engine, highlighting its design for enhanced responsiveness and power.
This sophisticated approach minimizes negative interference between individual cylinders during load cycles, optimizing the gas cycle. The outcome is enhanced torque output at lower engine speeds and exceptionally quick turbocharger responsiveness, virtually eliminating turbo lag.
Furthermore, a significant advancement in turbocharger technology is the incorporation of roller bearings for the compressor and turbine shafts. This feature, borrowed from the high-output variant of the AMG 4.0-liter V8 engine in the AMG GT 4-door Coupe, minimizes mechanical friction within the turbocharger. As a result, the turbocharger reacts more promptly and reaches its maximum speed of up to 169,000 rpm with greater rapidity.
Electronic Charge Pressure Control for Optimized Performance
The 2.0-liter turbo engine achieves exceptional performance with a maximum charge pressure of 2.1 bar (1.9 bar in the base version). Electronically controlled wastegate (exhaust relief valve) technology enables highly precise and flexible charge pressure regulation, particularly enhancing responsiveness during acceleration from partial load conditions. This intelligent system factors in numerous parameters for optimal control.
Key input signals for the wastegate control unit include charge pressure, throttle flap position, and any indication of engine knocking. Modifying signals encompass intake air temperature, engine temperature, engine speed, and atmospheric pressure. This advanced control system also enables temporary charge pressure boosting (overboost) during acceleration, providing an extra surge of power when needed.
To manage the thermal demands of the turbocharger, a sophisticated cooling system utilizes fresh air, oil, and water. Fresh air is channeled from the radiator grille directly to the turbocharger via the engine cover, which is designed as an air deflector, and through ducts located beneath the hood. This cooling strategy 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. Integral insulation within the turbine housing further contributes to thermal management efficiency.
Crankcase Design and Closed-Deck Construction
The Mercedes 4 cylinder engine M 139 features an all-aluminum crankcase constructed using a chill-casting process, resulting in exceptional material properties. In this process, molten aluminum is poured into a metallic mold. The mold’s excellent thermal conductivity facilitates rapid cooling and solidification of the aluminum melt, yielding a fine-grained, dense structure with very high strength characteristics. Complex internal geometries are achievable through the use of enclosed sand cores during the casting process.
The engine employs a closed-deck construction, a design principle derived from motor racing. This design ensures outstanding rigidity with minimal weight and enables the engine to withstand peak combustion pressures of up to 160 bar. The areas surrounding the cylinders are primarily 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 with optimized piston rings, combines low friction operation with exceptional strength. The engine is capable of reaching a maximum engine speed of 7200 rpm, with peak power output achieved at 6750 rpm. The oil sump incorporates baffle plates to ensure consistent engine oil supply to all critical components, even under high lateral acceleration forces.
Alt text: Illustration of the Mercedes-AMG M139 engine crankcase, showcasing its closed-deck construction and high-strength aluminum material.
NANOSLIDE Cylinder Coating Technology
To minimize friction between pistons and cylinders, the cylinder liners in the Mercedes-AMG M 139 engine are treated with patented NANOSLIDE technology. This coating creates a mirror-like surface on the cylinder liners, significantly reducing friction. NANOSLIDE is twice as hard as conventional grey cast-iron liners, substantially enhancing durability and wear resistance. Developed by Daimler AG, NANOSLIDE is protected by an extensive portfolio of patents and has been successfully implemented in AMG engines for many years, including the Formula 1 engine of Mercedes-AMG Petronas Motorsport.
Enhanced Cylinder Head and Valve Design
Repositioning and slightly angling the fuel injection nozzles and spark plug system within the cylinder head of the Mercedes 4 cylinder engine M 139 allowed for the incorporation of larger exhaust valves compared to the preceding M 133 engine. These larger exhaust cross-sections facilitate more efficient outflow of gases from the combustion chambers, minimizing losses and reducing overall piston venting effort.
Improved cylinder head cooling is achieved through the use of seating rings with a reduced installed height and a cooling borehole strategically positioned near the combustion chamber, in the web area between the exhaust seating rings. Cooling performance is further enhanced by a near-surface water jacket geometry, promoting faster coolant flow and optimized volumetric flow rate. A multi-layered, state-of-the-art corrugated metal seal effectively isolates the cylinder head from the crankcase.
Two overhead camshafts control the 16 valves via weight-optimized roller cam followers. Camshaft adjustment on both the inlet and outlet sides ensures excellent engine response and optimizes the gas cycle across various operating points. Variable CAMTRONIC valve control on the exhaust side is another advanced feature, utilizing two cams per valve with differing geometries. Depending on the cam setting, exhaust valves can be opened for shorter or longer durations, optimizing engine performance for different driving situations – enhanced responsiveness at low engine speeds, fuel-efficient cruising at medium rpm, and maximum power delivery at high rpm.
Two-Stage Fuel Injection System
The Mercedes-AMG M 139 engine employs a sophisticated two-stage fuel injection system, combining the benefits of turbocharging and spray-guided direct injection. This approach not only yields high power output but also enhances thermodynamic efficiency, reducing both fuel consumption and exhaust emissions.
For the first time in a Mercedes-AMG high-performance four-cylinder engine, two-stage fuel injection is utilized. In the first stage, exceptionally fast and precise piezo injectors directly inject fuel into the combustion chambers at pressures up to 200 bar. This process is often multi-stage and is precisely controlled by the engine management system. The second stage involves additional intake manifold injection using solenoid valves. This supplementary injection system is crucial for achieving the engine’s high specific output. The electronically controlled fuel supply operates at a pressure of 6.7 bar.
Advanced Cooling System for Sustained Performance
The high power output of the Mercedes 4 cylinder engine M 139 necessitates an intelligently designed cooling system. An auxiliary radiator positioned in the wheel arch complements the primary radiator in the front module. A low-temperature circuit is also incorporated for air/water intercooling. A high-performance electric pump, working in conjunction with the series-connected intercooler, optimizes coolant flow through the radiators. This system ensures effective cooling of the highly compressed charge air, contributing significantly to maintaining optimal engine performance under demanding conditions. Transmission oil cooling is integrated into the engine’s coolant circuit and is further supported by a heat exchanger mounted directly on the transmission. The engine control unit is strategically located on the air filter housing, where it benefits from airflow cooling.
Electric Water Pump for Enhanced Efficiency
The demand-controlled, electric high-performance water pump operates independently of engine speed. 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 switched on or off as needed during periods of lower power demand or low engine speeds. Furthermore, the electric water pump ensures consistent engine output and optimal heat dissipation across the entire engine speed range, and provides protection against thermal damage during idling in high ambient temperatures.
Additional technologies integrated into the Mercedes-AMG M 139 engine include alternator management, ECO start/stop function with rapid restarting, gliding function, and a gasoline particulate filter, further enhancing efficiency and reducing environmental impact.
Modern Assembly Process and Enhanced Efficiency
The Mercedes-AMG 2.0-liter turbocharged four-cylinder engine M 139 is assembled entirely by hand, adhering to the traditional AMG “One Man, One Engine” principle. However, the assembly process has been revolutionized with digitally supported workflows and optimized logistical organization. The focus remains firmly on the assembly technicians, who are supported by digital tools to enhance their work. The production process emphasizes intelligent and flexible technology. A combination of highly flexible line assembly and preconfigured shopping carts utilizing driverless transport systems forms the core of this modern manufacturing approach. Sustainability was a key consideration in the design of the new M 139 production line, with renewable energy sources used in production, significantly reducing CO2 emissions, water consumption, and waste.
The assembly cart used for M 139 engine construction was co-developed with the assembly employees. It features an independent power supply, eliminating the need for power cables. All necessary operating fluids and tools are ergonomically arranged on the cart, streamlining workflows, minimizing distances, and improving efficiency. An integrated tablet PC provides technicians with precise and clear work instructions, eliminating paper-based manuals and guidelines and creating a paperless manufacturing environment. Cordless screwdrivers are readily accessible, replacing suspended, wired tools and creating a cleaner and more efficient workspace, which employees have nicknamed “blue sky” due to the absence of overhead power cables. Comprehensive digitization enhances both manufacturing efficiency and flexibility. Each tool is connected to the engine assembly shop’s WLAN, enabling automated enabling and torque settings for each assembly stage through indoor tracking. All completed tasks are digitally recorded, ensuring optimal quality assurance, reproducibility, and transparency.
Each assembly technician is accompanied by a driverless transport system carrying a shopping cart pre-loaded with the exact components required for the engine being assembled. These transport systems are loaded at the Mercedes-AMG logistical center in Marbach and delivered to the production line in a “just in sequence” manner. Indoor tracking via WLAN enables autonomous control of the transport systems, and all components are digitally tracked throughout the process. The assembly and transport carts feature a black-and-white Mercedes-AMG design and slogans, fostering motivation and brand identification. The shop floor incorporates design elements reminiscent of racetracks, further reinforcing AMG’s performance heritage.
Efficiency gains have also been realized through a reduction in the number of test stations. Several individual stations have been consolidated into three central stations: drag torque test, leakage test for oil/coolant and fuel systems, and complete engine water jacket test. This consolidation results in significant time savings and enhanced efficiency. All parameters and measured values are digitally recorded and stored, providing a complete digital record of the assembly of each individual engine.
The “One Man, One Engine” assembly philosophy remains a hallmark of the Mercedes-AMG brand. A defining characteristic of the M 139 engine is the AMG engine plate bearing the signature of the assembly technician, a testament to the handcrafted nature and individual accountability in the engine’s creation. All assembly technicians for the new four-cylinder engine underwent extensive specialized training for the M 139.
Mercedes-AMG M 139 2.0 liter turbocharged four-cylinder engine – Technical Data
| Feature | Specification |
|---|---|
| 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 twin-scroll 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 |
| Direct Injection | Third-generation multiple direct injection, piezo injectors, up to 200 bar |
| Manifold Injection | Additional intake manifold injection with solenoid valves, 6.7 bar |
| Cylinder head | Two overhead camshafts, 16 valves, adjustable intake and exhaust camshafts, CAMTRONIC exhaust valve timing |
| Max. air mass throughput | 2,645 lb/h (S-model) / 2,425 lb/h (base version) |
| Engine weight (wet) | 353.8 lbs |
