Mercedes-Benz M 120
| Mercedes Benz | |
|---|---|
|
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| M 120 | |
| Manufacturer: | Daimler Benz |
| Production period: | 1991-1998 |
| Design: | Twelve-cylinder - V engine |
| Previous model: | none |
| Successor: | M 137 |
The motor type M 120 is a twelve-cylinder - V engine of Daimler-Benz and the first series-produced car twelve-cylinder of the brand Mercedes-Benz . The gasoline engine with six liters of displacement and four-valve technology was from 1991 to 1998 in the sedans and coupes of series W 140 / C 140 used later in the SL series R 129 .
The engine type was replaced in 1999 for use in the S-Class of the 220 series (later also in other series) by the somewhat smaller and lighter M 137 . The M 120 is also used in an optimized form as the M 297 in some sports cars and luxury sedans , for example in the Pagani Zonda , the Mercedes-Benz CLK GTR and the Lotec Sirius . The Mercedes-Benz test vehicle C 112 was equipped with the M 120 and used together with the manual six-speed gearbox for test drives.
Origin and technology
In the mid-1980s, Daimler-Benz began developing a new S-Class, which was to be presented in 1991.
In the luxury sedan market segment, only the British brand Jaguar had a V12 on offer in the XJ Mk. I from 1972 , otherwise twelve-cylinder engines were the domain of sports car manufacturers such as Ferrari and Lamborghini .
In addition to the tried and tested M 117 V8 engines , a twelve-cylinder engine for a planned “600 SEL” had already been developed for the 126 series, which was in production . However, it seemed unwise to present such a large engine in the aftermath of the 1974 oil crisis, and Daimler decided not to open it for series production.
In 1987, BMW presented the 7-series 750i, the first twelve-cylinder engine in a car in German post-war history. Daimler-Benz now decided to do the same as its fiercest competitor and also to include passenger cars with twelve-cylinder engines in its range.
In 1988 Dr.-Ing. Kurt Obländer commissioned the development of a twelve-cylinder engine for the new S-Class 140 series, which appeared in 1991 , which would by far exceed the Bavarian unit in terms of output and displacement and develop at least 294 kW (400 hp). At that time, a new 5.6-liter V8 engine with four-valve technology and almost 400 hp had already been developed under the code M117 / 9 , which the tuning company (and later Daimler subsidiary) AMG initially produced alone. These units were later produced in a simplified design together with Daimler-Benz and installed in coupés and sedans of the 126 series for solvent customers.
At the same time, Obländer had developed an eight-liter V16 with around 540 hp ready for series production for the initially planned “800 SEL” model of the W 140, but Daimler-Benz shrank from its series introduction, similar to the introduction of the V12 engine in the previous W 126 series .
The new six-liter V12 introduced with the W 140 series developed 300 kW (408 hp). This engine was not only the first series-produced twelve-cylinder car from Mercedes-Benz, it was also the most powerful Mercedes-Benz car engine to date. The maximum torque is 580 Nm and already exceeds the 500 Nm mark at 1600 rpm. The V12 is equipped with a camshaft adjustment of the intake camshafts as well as a fully electronic Bosch injection system with a hot wire air mass meter ( LH-Motronic ).
In engine development, the focus was on minimizing pollutant emissions and fuel consumption. The electronic ignition calculates the optimal ignition point from 300 ignition maps, individually for each cylinder and adapted to the knock limit. The M 120 is the only twelve-cylinder in the world to have this cylinder-selective anti-knock control. This is the only way to achieve the high compression ratio of 10: 1 required for optimal fuel utilization. The engine and drive management was innovative, in which all control modules communicate with one another via a common data channel ( CAN bus ). This is used, among other things, to quickly heat up the catalytic converters after a cold start of the engine, as well as for traction control and for the new engine drag torque control, which prevents a car from breaking away on a slippery road as a result of taking the accelerator away.
The engine's exhaust system houses the world's largest catalytic converter system for cars. With a volume of seven liters, it was dimensioned so that the catalytic converter does not consume more fuel and ensures high long-term stability. Thanks to a new concept of double-walled and three-layer insulated exhaust manifolds and also double-walled supply lines, the ceramic catalytic converters embedded in a heat-insulated swelling mat reach operating temperature in a short time.
After public criticism became loud, in September 1992, three years after the completion of the M 120, Daimler-Benz decided not to use mixture enrichment at full load, which injected more gasoline than was allowed to convert the pollutants. The manufacturer modified the engine management system, which resulted in a loss of power of 1/30 (3.33%) or 10 kW (14 PS) to 290 kW (394 PS) and a small reduction in torque to 570 Nm.
Series vehicles with M 120
From 1991
- in the 600 SE , (from 06/1993 S 600 ) W 140
- in the 600 SEL , (from 06/1993 S 600 long ) V 140
From 1992
Performance improvements
AMG developed various engines with 6.9, 7.0 and 7.3 liter displacement based on the M 120. a. were used in the CLK-GTR, the SL 70 AMG and the SL 73 AMG. Today, for example, they are still installed in the Pagani Zonda sports car . These engines are called M 297.
In the Supersport version of the Mercedes CLK GTR, the M 297 generates 488 kW (663 PS), while the engine in the Pagani Zonda F in its Club Sport version is still 478 kW (650 PS).
Tuning companies also worked on the M 120. From Brabus , Lorinser , Koenig-Specials, Renntech, Väth and Carlsson there was the twelve-cylinder with displacements between 7.2 and 7.4 liters. The Brabus 7.3S with an output of 428 kW (582 PS) is very well known. The performance range extends to the lesser known Carlsson RS74 Le Mans with up to 456 kW (620 PS). The torque of the different displacement versions ranges from 720 to 850 Nm.
There are also two complex conversions of the M 120 to a turbo engine. The Lotec GmbH in Kolbenmoor has left it at the standard six liters, however, two exhaust gas turbochargers (K 27) together with the charge air cooler fitted and the engine in Lotec Sirius installed. It develops an output of 735 kW (999 PS) and a torque of 1100 Nm at 0.85 bar boost pressure. With 1.2 bar boost pressure that can be called up for a short time, it is 883 kW (1,201 hp) and 1320 Nm. For comparison: the Bugatti Veyron super sports car with an 8-liter sixteen-cylinder engine and four turbochargers generates 736 kW (1,001 hp) and 1250 Nm.
Another version of the M 120 with exhaust gas turbocharging comes from the Russian tuner A-Level. This engine delivers 616 kW (838 hp) through twin-turbo charging and an enlarged displacement of 6.7 liters, and develops 1182 Nm of torque. This engine was installed in an S-Class Coupé from the C 140. The Lotec Sirius and the S 600 Coupé A-Level are one-offs.
Nowadays hardly any tuner does without a compressor or exhaust gas turbocharger to increase performance, since, in contrast to the large displacement versions of a naturally aspirated engine, they are much more economical, have a higher degree of efficiency and thus consume less fuel in relation to performance. The issues of durability, comfort and delayed power delivery (“ turbo lag ”) have meanwhile been satisfactorily solved, so that these engines have found their way into the sedans from Mercedes-Benz and Maybach .
Larger engines than the M 120 C 74 from Carlsson (7414 cm³) will probably hardly be developed for passenger cars in Germany in the future, as discussions about CO 2 emissions, gasoline prices, fuel consumption and alternative drive technologies are increasingly coming to the fore. Since around 2008, the trend towards “downsizing” with smaller, lighter and more economical engines has been going on at Daimler AG in particular, so that a four-cylinder diesel engine has also been available in the S-Class since the 221 series was introduced .
Data
- Engine type: M 120 E 60
- Installation position in the vehicle: front, lengthways
- Number of cylinders: 12
- Cylinder arrangement: V-shape
- Cylinder bank angle: 60 °
- Bore × stroke: 89.0 × 80.2 mm
- Displacement: 5987 cm³
- Compression ratio: 10.0: 1
- Valves per cylinder, arrangement: 4 (2 inlet, 2 outlet), V-shaped hanging
- Valve control: DOHC, two overhead camshafts per cylinder bank, inlet camshafts adjustable
- Camshaft drive: duplex roller chain
- Ignition: electronic with map control
- Cooling: liquid cooling, 18.5 l cooling liquid
- Lubrication: pressure circulation lubrication, 9.5 l oil
- Mixture formation: intake manifold injection with hot wire air mass measurement (Bosch LH-Jetronic)
- Output: 300 kW (408 hp) at 5200 rpm; from 09/1992: 290 kW (394 hp) at 5200 rpm
- Torque: 580 Nm at 3800 rpm; from 09/1992: 570 Nm at 3800 rpm
