Thursday July 18 2013

What is the Kompressor?

By Mustafa Ziraba

Kompressor. I simply love the way it rolls off the tongue. Kompressor is a badge on Mercedes Benz cars and simply means supercharger. Supercharging, or turbocharging, has been used to boost a car’s power and speed since at least 1921. And of course you guessed it, the first supercharged cars came through in 1921 by a Daimler-Benz team with assistance from Ferdinand Porsche.

So how exactly does a Kompressor aka supercharger work? See, the ingredients for combustion in an engine are air, fuel and a spark. What a supercharger does is to mechanically increase the air intake over and above what the engine would have taken in naturally from the atmosphere. The presence of this extra air intake obviously begs for more fuel to be accepted into the combustion chamber at once, greatly increasing horsepower. Enter the Kompressor.

The amount of air the engine can consume, mixed with fuel, and burn determines how much power the engine can make. Usually, engines of greater displacement can consume more air and fuel and make more power.

The downside to this is that engines of greater displacement have larger internal friction surfaces inside making them less efficient and that robs power. In town driving a car requires very little power to maintain speed on level ground. This is the biggest reason that smaller engines get better mileage than larger engines.

The problem is, there are times that you need much more power like when overtaking or going uphill. This is where a bigger engine comes in handy, but you pay a fuel penalty when that larger engine is not needed.

There are advantages to making a smaller engine more powerful. That way they can make the power needed, and still get better fuel economy. Enter the Kompressor again where you get a small engine that is extremely efficient but develops required power with the use of the supercharger when needed.

In other instances, a Kompressors is deliberately used to increase engine power even further as the engineering and space constraints might not allow for a size increase in an already big engine.

So you will not be hard pressed to find machines like the G-Class or SLS with huge displacement rocking Kompressors. A Kompressor model can achieve very similar or better mileage to a naturally aspirated engine of the same displacement if it is driven very gently and the supercharger is not engaged very often. However, if you start to drive more aggressively and allow the supercharger to engage, fuel consumption will increase very quickly.