In principle, Rudolf Diesel already planned the supercharging. However, there were too many problems with the realisation of the diesel engine as such. The
Swiss Alfred Büchi received in 1905 in Germany the patent for the turbocharger.The year 1924 marked the first ship diesel with this charge system.
It is not by chance that the history of the turbocharger starts with big diesel engines. A big diesel engine has, except through the construction and the material, no limitation of the boost pressure. The limitation of the
petrol engine is the knocking combustion. Because the diesel engine always works with excess air, its behaviour does not change with even more excess air, on the contrary, its smoke ejection becomes lower. The
petrol car should always keep a Lambda of 1. It is possible to use the loader of the diesel engine even exclusively for meeting certain exhaust emission standards.
The missing throttle valve causes with part load
a strong fresh gas flow which subsequently also keeps the turbine going with exhaust gases. The gas flow from lower part load to full load is considerably steadier than for the petrol engine. And if a turbo lag should
exist, nevertheless, it is easier forgivable for the big diesel engines than, for sporty petrol cars.
How it works
It has a place of honour on top of the engine. Not because it is prone to failing and would be easier to exchange. Rather because of the huge heat development. The charger must work really hard in the truck. The
boost pressure is higher than for the passenger car, already briefly above idling speed. The green band of trucks lies between 1200 rpm and 1900 rpm.
Like the diesel technology is more worthwhile for big engines than for small, the same holds true for the turbo-supercharging. A large volumetric flow makes the charger work more steadily and support the engine
better. Additionally, there is the smaller speed range in which the truck engine is typically operated. You do not have to be a clairvoyant to predict that the turbocharger will become even more important for the truck. In
countries with far higher gross weights like the USA and Australia engines with more performance are operational, often with the same cylinder number, but with stronger charging.