MW-50

MW -50 was the abbreviation for a methanol -water mixture with a mixing ratio of 50:50, which was used in World War II with the German Luftwaffe to increase the performance of turbocharged diesel engine. Aggregates, the MW -50 used primarily came in fighter aircraft such as the Bf 109 or Fw 190 used, so that the pilots could operate in critical situations, the engines briefly with increased power ( " Sondernotleistung ").

Mixing ratio

MW -50 consisted of 50 % methanol, 49.5% water and 0.5 % protection oil. This mixture had a specific gravity of 0.9 kg / l and was cold-resistant down to -50 ° C. Next MW MW -30 and 50 also EW- 30 (Ethanol instead of methanol ) were used to a lesser extent. MW -30 consisted of 30 % methanol, 69.5 % water and 0.5 % protection oil. This mixture had a specific gravity of 0.95 kg / l and was cold-resistant to -18 ° C.

Operation

The principle is based on the possibility of improving the performance of supercharged engines with intercooling. A variant of the charge air cooling is the internal cooling of the charge air by injecting a liquid into the charging passage means, said liquid charge of the heated air escapes by evaporation heat. The cooled gas mixture contains a greater amount of fuel into a given volume, so that more oxygen molecules per unit volume available for the combustion of the fuel is available. This improves the volumetric efficiency of the engine; can be delivered by the increased pressure thus means a better performance. A pure water injection would be more effective as a MW -50 injection, since water has a higher heat of evaporation. MW -50 developed about half as large heat of evaporation as pure water. The addition of methanol was carried out in order to prevent uncontrolled ignition (so-called "tapping ") and freezing at high altitudes. Furthermore, the methanol is increased due to its calorific value thermal conversion in the combustion and reduced the corrosion in the engine. MW -50 was injected at a pressure of 4 bar.

Use

The performance increase was permitted up to a period of ten minutes at a sufficient engine cooling, before a repeated use of the engine had to be operated at a lower power level for at least five minutes. If the engine is not overheated, the lifetime of the spark plug has been reduced. Later, the operation was extended for motors with good cooling performance up to 20 minutes. The performance gain with a consumption of 150 l / h was about 300 horsepower depending on the engine. The Fw 190 D could operate a total of 40 minutes, with its 115 -liter tank, the injection.

The use of this technique was only useful up to full pressure height of the engine, since above this level, the charger could no longer provide the required maximum capacity of air for combustion of the fuel.