Mercedes-AMG
M 133
Manufacturer:	Mercedes Benz
Production period:	since 2013
How it works:	Otto
Style:	Line four-cylinder
Engines:	2.0 liters (1991 cm³)
Successor:	M 139

The M 133 is a petrol engine with four cylinders arranged in series by Mercedes-AMG , which is available since June 2013 in the third generation of the A-Class (W 176) as A 45 AMG on the market. The production takes place by hand at MDC Power GmbH in Kölleda . With a displacement capacity of 140 kW / l, it is the third largest mass-produced four-cylinder engine, which was previously installed in an approved for use on public roads car model factory (motor 4B11T in the Mitsubishi Lancer Evolution X : 150 kW / and 161 kW ).

When M 133 is a four-cylinder - Series - petrol engine with a displacement of 1991 cc. In the original version the power was 265 kW (360 hp) at 6000 rpm (maximum speed: 6700 rpm) and the torque 450 Nm at 2250 to 5000 rpm. Since 2015 the power is 280 kW (381 hp) at 6000 rpm and the maximum torque 475 Nm at 2250 to 5000 rpm.

At best, the engine achieves a specific fuel consumption of 234 g / kWh. The maximum effective mean pressure is over 28 bar. 

The engine is based on the M 270 front-to-rear serial aggregate from which it takes on all the basic structural dimensions, such as bore (83 mm), stroke (92 mm) and cylinder spacing (90 mm), since the aim is to achieve the greatest possible blocking . To achieve the high specific power, however, the engine was adapted for higher ignition pressures of up to 150 bar. The compression ratio is 8.6: 1. 

The in mold Kippgussverfahren prepared crankcase of M 133 is in closed-deck design carried out and consists of the aluminum alloy AlSi7Mg. The cylinder head is made of the aluminum alloy AlSi10MgZr, where the addition of zirconium has increased the thermal conductivity . 

The charge cycle is controlled by four valves per cylinder and two overhead camshafts driven by a timing chain . For both the intake and the exhaust camshaft a camshaft adjustment of 40 ° crank angle is possible. 

The crankshaft drive with a forged steel crankshaft (44MnSiVS6) with inductively hardened bearing surfaces, gray cast iron crankshaft bearing caps and forged pistons made of a racing alloy with friction-optimized piston rings also contribute to a weight- optimizing function. The M 133 weighs 147.8 kg according to the DIN standard. 

The entire air gap from the air inlet to the inlet channels into the cylinders is very short, with a total length of less than 1.2 m, to allow a spontaneous response. The motor is with a twin-scroll - turbocharger equipped, whereby the torque build-up takes place quickly, even at low speed ranges. The maximum boost pressure is 1.8 bar relative to the atmospheric pressure. The intercooler is indirectly via a separate low-temperature cooling circuit, whereby the charge air temperature is a maximum of 25 K above the ambient temperature. 

Injection

The M 133 belongs to the family of BlueDirect direct injection engines with piezo injectors in all four combustion chambers. When the engine is warm, it injects up to three times per cycle (two pre-injections for better mixture preparation), while the engine warms up to five injections per cycle to reduce particulate emissions. The M 270 base engine took over the injector and spark plug position, the inlet duct geometry and the entire combustion chamber roof configuration.

Cooling system 

The cooling system is largely based on the M 159 engine used in the SLS AMG sports car , but has been expanded to include a low-temperature cycle for air-to-water intercooling . There is also an additional radiator in the wheel arch. The water coolers are flown through by an electric pump and the series-connected intercooler. The cooling of the transmission oil is coupled to the engine-side high-temperature cooling circuit, however, the coolant removed therefrom is additionally cooled by a lying, installed in front of the radiator pack auxiliary cooler before it enters the gearbox mounted on the heat exchanger.

The redesign of the cooling system allows water temperatures below 110 ° C to be achieved over the entire map range and under all climatic conditions. Among other things, the delivery rate of the coolant pump was increased by 15%. 

M 133 DE 20 AL