The turbocharger turns 100 years old this week

The turbo-charger , which has dominated the development of the internal combustion engine for the last 30 years, turned 100 years old this week. On 16 November 1905 Swiss engineer Dr. Alfred Büchi received patent No. 204630 from the Imperial Patent Office of the German Reich for a "combustion machine consisting of a compressor (turbine compressor), a piston engine, and a turbine in sequential arrangement". Porsche chose the occassion to introduce its very latest take on the turbocharger, this time with variable turbine geometry (VTG). This extensive article covers the development and major achievements of the turbocharger and the new VTG technology which realises even more efficiency, resulting in a significant improvement of engine flexibility and acceleration particularly at low engine speeds. In introducing the new 911 model some 31 years after it gave us the first series production sports car with an exhaust gas turbocharger (the 1974 Porsche 911 Turbo), Porsche will be presenting the world's first turbocharged gasoline engine with variable turbine geometry (VTG).

This technology featured in turbocharged diesels since the '90s ensures a significant improvement of engine flexibility and acceleration particularly at low engine speeds. So far, however, much higher exhaust gas temperature of up to 1000° C in comparison with the turbocharged diesel has always proved to be an insurmountable barrier. But now Porsche has solved this problem in close cooperation with Borg Warner Turbo Systems by using high temperature-resistant materials from space technology wherever required.

The very concept of turbocharger technology is linked inseparably with the name Porsche and the Porsche brand. It was back in October 1974 that the German sports car manufacturer from Stuttgart launched the world's first series production sports car with an exhaust gas turbocharger. And ever since, each new generation of the Porsche 911 Turbo has fascinated enthusiasts the world over with a new and distinctly better enhancement of the technology: the intercooler, bi-turbo, VarioCam Plus, as well as the title "Cleanest Car in the World" have all set the benchmark in turbocharger development. Now the new competitive edge of the next generation of the Porsche Turbo is spelt VTG - variable turbine geometry.

The core features of VTG are the variable turbine blades guiding the flow of exhaust gas from the engine in exactly the direction required on to the turbine wheel of the exhaust gas turbocharger. The principle of variable turbine geometry thus combines the benefits of a small and large exhaust gas turbocharger all in one – a combination ensuring both very good response and high torque at low engine speeds as well as superior output and high performance at high speeds. And the supreme level of torque is now maintained consistently throughout a much wider speed range.

Happy Birthday The exhaust gas turbocharger was invented exactly 100 years ago: On 16 November 1905 Swiss engineer Dr. Alfred Büchi received patent No. 204630 from the Imperial Patent Office of the German Reich for a "combustion machine consisting of a compressor (turbine compressor), a piston engine, and a turbine in sequential arrangement".

Born on 11 July 1879, Büchi, who died on 27 October 1959, worked as an engineer in the Swiss town of Winterthur. His idea was not just to pre-compress the air flowing into the engine, but also to use the kinetic energy coming out in the exhaust gas under high pressure, which otherwise was simply wasted. So he used the exhaust gas flowing out after the combustion process to drive a turbine serving, in turn, to drive a compressor pre-compressing the intake air and boosting the air charge in the engine. This marked the birth of the turbocharger.

Büchi had to wait a long time until his invention was able to enter practical use. The first application of turbocharger technology was in large marine engines, with the German Ministry of Transport commissioning the construction of the "Danzig" and "Preussen" passenger liners in 1923. Each of these two passenger ships had twin ten-cylinder diesel engines with output boosted by turbocharger technology from 1750 to 2500 horsepower.

The first attempts to use this technology in the automobile began in the late '50s, with the so-called "turbo gap" – the delayed response of the engine to the throttle – presenting development engineers with a challenge still insurmountable at the time.

In 1973 Porsche raced the 917/30 developing more than 1100 bhp as a spearhead in turbocharger technology in the US CanAM Series, this ultra-powerful racing car literally destroying its opponents on the track. The result was a modification of regulations in the CanAM Series sending the almighty 917/30 straight to the museum.

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