Mercedes-Benz M 272 V6 petrol engine 

Mercedes Benz
M 272
Manufacturer:	Mercedes Benz
Production period:	since 2004
Style:	V , six-cylinder
Engines:	2.5 liters (2496 cc)  to 3.5 liters (3498 cc)
Previous model:	M 112
Successor:	M 276

The M 272 is a petrol engine with six cylinders in V-arrangement from Mercedes-Benz . Since 2004, with the introduction of the new SLK-Class ( R 171 series ), it has been offered as a naturally aspirated engine with classic intake manifold injection in most Mercedes-Benz passenger car models; since 2006 in the CLS-Class ( C 219 series ) also with direct injection (CGI ). The engine type is related to the V8 cylinder gasoline engine M 273which originated in the same development cycle. This is why the M 272 also has the cylinder bank angle of 90 ° which is not typical for six-cylinder V engines, which requires an additional balancing shaft.

The M 272 and M 273 engines, in contrast to their three-valve M 112 and M 113 precursors, have four valves, one centrally located spark plug per combustion chamber and two chain-driven cams per cylinder bank ( DOHC ). The valves are operated via roller rocker arms with fixed hydraulic valve clearancecompensation. The intake and exhaust camshafts can be adjusted independently of each other continuously in phase. In addition, the motors have a variable intake manifold with two switchable lengths of the ducts to the individual cylinders.

The engine block of the M 272 is made of light metal, with cast-in cylinder liners made of an Al - Si alloy. The crankshaft bearing caps made of gray cast iron are bolted to stabilize the engine block also laterally. The cylinder bank angle is 90 °, and the split crankpin crankshaft sit side by side without intermediate cheek. Above the crankshaft in the cylinder V, as with the precursor, there is a balancing shaft for eliminating the first-order free mass forces, which is driven together with the camshafts by a double-sleeve chain.

In the suction tubes tumble flaps are pivoted, which generate at partial load turbulence of the mixture, whereby the combustion is faster and more uniform. As a result, a higher proportion of exhaust gas in the mixture is possible, which is controlled by the adjustment of the exhaust camshaft. The advantage of this "internal exhaust gas recirculation" is a higher efficiency through de-throttling and higher effective compression due to the larger cylinder filling.

Use 

The engine type is used in the C- , E- and S-Class , as well as in the CLS , CLK , SLK and SL , as well as in the R-Class and SUVs GLK and ML , furthermore in the Sprinter W 906 and the Vito / Viano as 3.5 liters with 190 kW (258 hp).

Mercedes offers the M 272 in six different versions:

• M 272 KE 25: Model designation "230" or "250"
• M 272 KE 30: Model designation "280" or "300"
• M 272 KE 35: Model designation "350"
• M 272 KE 35: Model name "350 Sportmotor"
• M 272 KE 35: Model "S 400 Hybrid" with 205 + 15 kW (279 + 20 hp)
• M 272 DE 35: Model name "350 CGI"

The CGI version of the 3.5-liter engine was in the CLS and the end of 2007 in the E-Class 211 series and its successor series 212 / 207 available.

Since the beginning of 2008, both the SLK (R171) and the facelifted SL (R230 Mopf 2) have been offered with a new 3.5-liter sports engine. This has the normal intake manifold injection, but has been increased in performance (including by raising the maximum speed). He makes between 224 and 232 kW (305-316 hp). Background to the sports engine: The more modern CGI machine is a bit higher due to the design and therefore does not fit under the flat bonnet of the Roadster.

This engine was mainly offered with the automatic transmission 7G-Tronic, but also with 6-speed manual transmission (eg in the SLK R 171). Basically, this engine is considered reliable, the first versions had problems (material wear) with a sprocket on the balancer shaft . Successor of the M 272 is the Mercedes-Benz M 276 .

Data

 * Engine designation is encrypted as follows: M = engine (Otto), series = 3 digits, KE = port injection, DE = direct injection