Comments on: Why do diesel engines use turbos insted of using superchargers?

By: db79300

db79300 — Sat, 12 Apr 2008 12:12:59 +0000

That is a good question. Turbos, which are placed in the engine exhaust system, capture some of the energy that would otherwise have gone out the tail pipe. That captured energy spins a compressor that forces more air (oxygen) into the combustion chambers to markedly increase the engine power. Supercharging does the same thing but the compressor is belt driven off the crankshaft. Operating the compressor in this fashion subtracts some the horsepower gained by pressurizing the incoming air. Superchargers are heavier, more complex and take up more space than turbos. Superchargers however, produce power right from the start of the rpm band and are capable of far more boost.

By: Bob H

Bob H — Fri, 11 Apr 2008 20:24:42 +0000

Turbos are exhaust driven ( in the exhaust pipe ) and work best when the RPM range is narrow. A diesel might be useful at 1,000 to 2,000 RPM. Plus they’re cheap. Superchargers are belt driven and will work at a wider range (2,000-8,000) as on a dragster. Diesel engines have very low valve lift and can’t use high volumes of forced air whereas ignition engines can use much higher volumes of mixture due to high valve lift and overlap.

By: Mad Scientist Matt

Mad Scientist Matt — Fri, 11 Apr 2008 02:20:57 +0000

Both of them cram more air into the engine. There are supercharged diesels - many locomotives are supercharged, and the GMC 4-71, 6-71, and similar superchargers were originally used on diesel engines too.