Mercedes-Benz M271 engine (2002-17)

The Mercedes-Benz M271 was an inline, four-cylinder petrol engine that was first introduced in 2002 and replaced the M111 engine. Manufactured at the Mercedes-Benz plant in Stuttgart-Untertürkheim, Germany, the M271 engine had a cast aluminum block with cast-in iron cylinder liners, a cast aluminium cylinder head, fracture split-forged steel connecting rods, double overhead camshafts (driven by a single roller chain), independent intake and exhaust camshaft timing, and four valves per cylinder. The M271 engines with conventional port injection had Siemens 4 LKE SIM engine management.

Compared to its M111 predecessor, the M271 engine had:

• Centrally-located spark plugs;
• A Lanchester balancer which eliminated second order inertial forces, though the 1.6-litre variant omitted the balancer for greater efficiency; and
• Forced induction with charge air cooling.

From 2003 to 2005, the M271 engine was available with direct petrol injection (‘CGI’) which operated at pressures from 50 to 120 bar. The direct injection engines had two separate intake ports, each of which had an adjustable swirl flap so that turbulence generated in the intake air enhanced the efficiency of the combustion process. The direct injection engines had Siemens SIM 4 LDE engine management.

M271 EVO

Available from September 2009, the M271 EVO engine had a turbocharger in place of the M271’s supercharger. Since the turbocharger did not require engine power to drive the compressor, the engine’s efficiency was improved. Other benefits included lower production costs, more compact packaging, an approximate 4 kg mass reduction and reduced noise and vibration characteristics. The M271 EVO engine was first offered in the E 250 CGI BlueEfficiency.

From 2010, M271 EVO engines with six-speed manual transmissions were available with an ECO start-stop function which enabled the engine to shut down when the vehicle was stationary in traffic.

While the M271 EVO engine was initially available with a five-speed automatic transmission, this was replaced by the seven-speed 7G-Tronic unit in mid-2011. However, the 7G-Tronic Plus transmission was introduced in September 2011 and included the ECO start-stop function.

The M271 engine was superseded by the M274 in 2011.