User:JSdeutsch/G-Lader
[This is the 6 November 2008 English rendering of the German Wikipedia article G-Lader as used for the English Wikipedia article G-Lader (which has been subject to editing since then). Translator's notes can be found under the discussion tab above.]
The G-Lader is a scroll-type supercharger used in various Volkswagen models. Its purpose is to increase the horsepower attainable with a given engine displacement. Since it is not enough simply to inject more fuel, as this produces too rich an air-fuel mixture, more intake air has to be added at the same time. This can be achieved with an exhaust-driven turbocharger or a belt-driven compressor. The G-Lader is in the compressor category, since it is belt-driven and does not have the turbocharger problem known as turbo lag.
History[edit]
This type of air pump, notable for low noise and high efficiency, was patented on October 3,1905 by Léon Creux of France (US Patent 801,182). Due to the very imprecise production methods of the period, however, it was not manufacturable for a long time, since the displacer (described below) inside the compressor comes within tenths of a millimeter of the housing wall without making contact. Only with the more advanced engineering methods of the 1980s did it become possible to produce the G-Lader.
Contrary to expectations, Volkswagen's often problematic designs turned out to need relatively frequent repair in normal operation, which was one of the reasons why that manufacturer eventually abandoned this technology. The main cause of its relatively high failure rate was that Volkswagen misrepresented the G-Lader as maintenance-free. Depending on RPM, load, and design details, various parts wear out, with results ranging from impaired performance to destruction of the G-Lader. Yet it is frequently possible to extend the life of the G-Lader, sometimes to several hundred thousand kilometers, by periodically overhauling it with suitable replacement parts.
Operation[edit]
The supercharger housing holds what is called the displacer plate (or just displacer), on both sides of which are spirals, with seals between the latter and the housing. The housing itself also has spirals on both sides that mesh with those on the displacer. Driven by the crankshaft, which is connected to the displacer shaft by a small belt, the displacer moves eccentrically with respect to the supercharger housing (like the rotor in a Wankel engine) and, through this motion, forces the intake air into a smaller and smaller space, ultimately producing a maximum gage pressure of 0.8 bar(g).
Sizes and car models[edit]
The German name G-Lader comes from the shape of the supercharger (Lader), which looks like the letter G. The displacer's spirals are either 40 mm deep or, in the larger version, 59.50 mm deep, i.e. close to 60 mm. This is the reason we see G40 and G60 in the names of VW models in which it was used:
- Golf GTI G60 (Golf Mk2)
- Rallye Golf G60 (Golf Mk2 - Limited to 5000 vehicles)
- Golf G60 Limited (Golf Mk2 - Limited to a special Volkswagen-Mortorsport series of 71 vehicles)
- Corrado G60 (Corrado 53i)
- Polo Mk2 G40 (Polo 86c - Limited to 500 vehicles)
- Polo Mk2F G40 (Polo 86c)
- Passat G60 Syncro (Passat 35i)