DI two strokes, A brief history.
The V-Due, mention Direct Injection two stokes and some plonker will mention the V-Due.
Nice bike but the injectors only injected fuel and so it had no time to atomize properly, leading to an utterly crap engine that set back the whole DI two-stroke thing by years in the public’s eye’s.
Aprilia SR50 Di-Tech, been zooming around for years now (2000-)
Using an injector from orbital which combines air and fuel at the nozzle, this set-up actually works! but only up to 10,000rpm after that there is not enough time to inject enough fuel and air in to the cylinder.
Really impressive power from low down.
Ski-Doo 600 e-tec, Injection done right
Using a brand new injector (Voice coil injector) this thing injects at 35BAR solving the time issue with brute force so the engine can rev like a monster and behave like a pussy low down.
The future?
hasn’t even got going yet, the 600 rotax under the new injection system, is made like a boggo old two stroke with it’s carb’d limitation’s for example short stroke two-stroke have terrible short circuiting, injection solves that, allowing more revs and longer piston and ring life, Roller bearings, great for minimal lubrication, but can’t really go past 13,000rpm for long, using shell bearings, situated in the gearbox oil and a sump(?) built around the conrod to scavenge the oil, you could easyly build a 20,000rpm two-stroke. Result? longer flater torque curve, much like a four-stroke.
I can’t wait to get my hands on one of these things.
