Mercedes-Benz M272 engine
The M 272 is a petrol engine with six cylinders in V - arrangement of Mercedes -Benz. It is offered as a naturally aspirated engine with manifold injection classical in most Mercedes -Benz passenger car models since 2004 with the introduction of the new SLK- Class (model series R 171), since 2006 in the CLS- Class (model series C 219 ) with direct injection ( CGI ). The engine type is related to the V8 - cylinder petrol engine M 273, which originated in the same development cycle. Therefore also includes the M 272 to the uncharacteristic six-cylinder V-engine cylinder bank angle of 90 °, which makes an additional balance shaft needed.
Description
The engines M 272 and M 273, in contrast to their three-valve precursors M 112 and M 113 four valves, a centrally located spark plug per combustion chamber and two chain-driven camshafts per cylinder bank (DOHC ). The valves are actuated via roller cam followers with stationary hydraulic valve clearance compensation. The intake and exhaust camshafts can be adjusted in phase continuously independently. In addition, the engines have a manifold with two switchable lengths of the channels to the individual cylinders.
The engine block of the M 272 is made of light alloy, with cast-in cylinder liners made of an Al -Si alloy. The crankshaft bearing cap made of cast iron are also laterally screwed to the stabilization of the engine block. The cylinder bank angle is 90 °, and the split journal on the crankshaft sit without intermediate cheek side by side. About the crankshaft in the cylinder V is as in the precursor a balance shaft to eliminate the free inertial forces of the first order, which is driven together with the camshaft by a double bushing chain.
In the suction pipes tumble flaps are pivoted, the produce at part load a swirling of the mixture, so that the combustion takes place more quickly and evenly. Thereby, 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 EGR " is a higher efficiency by de-throttling and higher effective compression due to the larger cylinder filling.
Data
DE = direct injection, KE = port injection
Use
It is used in C-, E - and S-Class, also in CLS, CLK, SLK and SL, as well as in the R-Class and the GLK and ML. In addition, the Sprinter W 906 and the Vito / Viano 3.5 liter with 190 kW (258 hp).
Mercedes offers the M 272 in 6 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 designation " 350 sports engine "
- M 272 KE 35: Model designation "S 400 Hybrid " 205 15 kW (279 hp 20 )
- M 272 EN 35: Model designation " 350 CGI "
The CGI version of the 3.5 liter engine series 212/207 offered in the CLS and the end of 2007 in the E-Class 211 series and its successors.
Since early 2008, both the SLK and the facelifted SL are offered with a new 3.5-liter sports engine. This has the normal port injection, but was increased in performance ( partly by raising the maximum speed). It delivers 224-232 kW ( 305-316 hp). The reason why the direct injection engine does not installs in these models is that the CGI machine has been designed for slightly higher and does not fit under the flat hood of the roadster.
Practical experience
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 deemed reliable, the first versions of problems ( wear and tear ) with a gear on the balance shaft had.
Successor M 276
Successor of the M 272 is the Mercedes- Benz M 276