Mercedes Benz
M 271
Manufacturer:	Mercedes Benz
Production period:	From 2002 to 2015
Style:	Line four-cylinder
Engines:	1.6 liters (1597 cc)  1.8 liters (1796 cc)
Previous model:	M 111
Successor:	M 274

The M 271 is a petrol engine with four cylinders arranged in series by Mercedes-Benz , which was introduced in 2002 as the successor to the M 111 .

It is manufactured at the Mercedes-Benz Stuttgart-Untertürkheim plant . The engine has been offered since 2002 in various Mercedes passenger car models. The first was made in 2002 by the C-Class 203 series . Meanwhile, he is also offered in the SLK , CLK and in the E-Class . He is also used in the Sprinter (W 906).

The engine series presented in 2002 showed a noticeable improvement in many properties compared to its predecessor M 111 . These include lower fuel consumption, improved smoothness, improved performance and torque characteristics, and a stronger focus on lightweight construction. A TWINPULSE package of measures, consisting of four-valve technology with centrally located spark plug, variably adjustable camshafts , balance shafts, adaptive drive dynamics and supercharger supercharging with intercooler to allow a high running smoothness and driving pleasure with low fuel consumption. 

The engine weighs 167 kg, that is 18 kg less than the M 111. The weight savings was a cylinder distance of only 90 mm, a die-cast aluminum engine block with cast-in cast iron - cylinder liners and made of a high strength aluminum alloy cylinder head reached.

To improve smoothness, the engine has a Lanchester compensation that eliminates the second-order free mass forces. This compensation is omitted in the 1.6-liter variant to save friction. The balance shafts are mounted in an aluminum housing, which is bolted in the oil pan from below to the crankcase. The counter-rotating balance shafts are driven by a single sleeve chain with low masses. In the crankcase and the oil pump of the engine is housed; it is driven by one of the two shafts by means of a pair of gears.

Two camshafts driven by a single roller chain operate the valves via roller cam followers. The valves themselves have a maintenance-free hydraulic valve clearance compensation. The intake and exhaust camshafts can be independently adjusted in phase independently. For this purpose, a newly developed Flügelzellenversteller with integrated control valve allows continuous adjustment of the most favorable control times, which has a favorable effect on the torque behavior at full load, fuel consumption and exhaust emissions.

Unlike its predecessor, all engines of the M-271 series have a charging means compressor . Compared to the supercharged M-111 engines, the compressor has been completely redesigned with the aim of improving air flow and efficiency. The air gaps between the rotors and the charger housing were reduced and the rotors received a novel coating. To reduce noise emissions, broadband silencers were installed on both the suction and discharge sides. The charge air is brought to the optimum temperature by a charge air cooler .

The motor control is calculated by the Siemens SIM 4 LKE. The adaptive drive dynamics monitors pedal movements and registers acceleration maneuvers. Thus, the system is able to detect whether the driver prefers a more comfort-oriented or a sporty driving style and adapts the characteristics of accelerator pedal and throttle valve.

According to the so-called "downsizing concept", the engine delivers the desired power with low displacement and high boost pressure. The engine is thus smaller and lighter, and at part load are smaller throttle due to the smaller displacement. Although the compression must be reduced with increasing boost pressure to avoid knocking at full load, but this disadvantage is compensated by the better cylinder filling again. 

By 2008, all versions had 82 mm bore and 85 mm stroke and thus a displacement of 1796 cc. From April 2008 to April 2010, the C 180 Kompressor will be available as the first BlueEFFICIENCY model. This has a M 271 with reduced to 1.6 liters capacity. For this purpose, the stroke was reduced from 82 mm to 75.6 mm for the same bore. The smaller displacement in conjunction with the demand-based control of the power steering pump, the longer Hinterachsübersetzung, low rolling resistance tires and other fuel consumption measures on the vehicle, such. As aerodynamic improvements or weight-reduced components for a lower fuel consumption. 

The engine variant without direct injection can be operated with Super E10 (ROZ 95). 

M 271 with direct injection 

Already announced at the launch of the M 271, the market launch of the M 271 with direct injection due to technical problems was postponed to mid-2003. First, as in the CGI C 200 ( C-class available), the M 271 DE 18 ML has also been CLK 200 CGI ( C / A209 used).

In this engine, the fuel is injected via an injector at 42 degrees and at a pressure of 50 to 120 bar (depending on the operating condition) into the cylinders, where the fuel forms a mixture cloud with the air. This is guided by specially shaped piston recesses to the spark plugs. The CGI engine has two separate intake ports, one of which is additionally equipped with an adjustable swirl flap. In this way turbulence is created in the intake air, which makes the combustion process more efficient. The injection pressure is generated by a high-pressure fuel pump. This is driven by the intake camshaft.

In contrast to the other M-271 engines, the Siemens SIM 4 LDE motor control system has been enhanced by specific functions such as the control of the pressure in the fuel line. In partial load operation, with a mean pressure of four to five bar, and at low speeds, the direct injection works in the stratified charge process . The fuel is injected relatively late into the air compressed by the piston. This creates an ignitable mixture in the region of the spark plug, while in the remaining combustion chamber there is a lean, hardly ignitable mixture. Outside this range, the direct injection is operated with the usual for catalyst engines air-fuel mixture (lambda 1). The nitrogen oxides accumulating in lean operationare filtered by a NO _x storage catalyst.

The fuel grade is Super Plus E5 (RON 98); refueling with Super E10 (ROZ 95) or Normal E10 (ROZ 91) is not possible even in exceptional cases, as the models must not be operated with a bioethanol addition of more than 5 percent.

Over the entire construction period, the direct injection engine was only available with the 6-speed manual transmission . In 2005 the engine was removed from the collection.

M 271 EVO 

After seven years of construction and more than one million units of the M 271 series, the M 271 EVO (EVO = Evolution) was launched in the E 250 CGI BlueEFFICIENCY in September 2009 . This represents a further development of the well-known compressor engine with direct injection and replaces the M 271 in some vehicles.

The newly designed variant received instead of the compressor, an exhaust gas turbocharger . In addition to the lower production costs, this has the advantage that the engine does not have to provide additional power for the drive of the compressor. This improves the efficiency of the engine. In addition, the turbocharger welded to the exhaust manifold is more compact, weighs around four kilograms less and scores higher than the compressor due to better noise and vibration characteristics. To regulate the pressure conditions, the loader has a wastegate and a recirculation valve .

A warm-up control interrupts the coolant flow when the engine is cold, which causes the engine oil to warm up faster, thus shortening the warm-up phase. The oil pump received a needs-based control.

The direct injection has been further developed and equipped with magnetic multi-hole injectors that inject the fuel at an angle of 30 degrees. The engine now operates in the homogeneous air-fuel mixture range of 14.6: 1 (lambda = 1) and dispenses with a stratified charge. 

Until mid-2010, the M-271 EVO engines were only available in conjunction with the automatic 5-speed transmission . Since then, the 180/200 CGI BlueEFFICIENCY models can also be ordered with the 6-speed manual transmission. The manual models have the ECO start-stop function. This feature automatically stops the engine as it rolls out of the traffic lights as soon as the vehicle rolls slower than 8 km / h, the brake is applied, and idling is engaged. If the driver presses the accelerator pedal or if he depresses the clutch pedal, the engine immediately starts automatically. In mid-2011, the 5-speed automatic transmission was replaced by a 7-speed automatic transmission (designation 7G-TRONIC), which has also been equipped with a start-stop function since September 2011 (designation 7G-TRONIC-PLUS).

Technical

M 271

M 271 EVO 

 * Engine designation is encrypted as follows: M = Engine (Otto), Series = 3 digits, E = Intake manifold injection, DE = Direct injection, Displacement = Deciliter (rounded), M = Compressor, A = Exhaust gas turbocharger, L = Intercooler, red. = reduced power, NGT = Natural Gas Technology