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Development of the Aprilia DITECH 50 engine.
ISSN: 0148-7191, e-ISSN: 2688-3627
Published December 01, 2001 by SAE International in United States
Annotation ability available
A good scooter engine needs the following characteristics:
- Simplicity and low weight;
- high specific power;
- great fuel consumption
Those characteristics are in line (mostly) with the specification of a modern two-stroke engine. However, the non-stop upward spiral of anti-pollution laws has imposed new limits to scooter engines.
Three immediate solutions are capable of operating in today's legislative environment:
- High speed four stroke engine (with or without catalyst / secondary air injection);
- Two stroke catalyzed engine (with or without secondary air injection);
- Two stroke engine with direct injection (the most revolutionary solution).
Aprilia has decided to follow the third way by presenting DITECH, a new perspective in the motorcycling world.
Obviously, as pioneer of this technology on small, high-speed engines, Aprilia has spent a great deal of time and money to solve the “application” related problems of the DITECH system, problems not previously encountered.
The biggest design and /or development challenges during the engine's industrialization have been:
- Air compressor lay-out / Crank shaft balancing;
- Air Fuel Rail: head and combustion chamber planning, spark plug positioning;
- Lubricant distribution;
- High altitude operation;
- Plug fouling under extreme ambient conditions.
This project has taken Aprilia through the creation of a totally new engine, with unique characteristics. With DITECH, a tremendous reduction of oil an fuel consumption and very low emission of exhaust smoke has been possible, without sacrificing “top end” performance and great mid range torque of a classic two stroke engine.
The potential of this new engine technology is very high, due to the relatively simple emissions package required to meet coming anti-pollution laws.
CitationAmbler, M. and Zocchi, A., "Development of the Aprilia DITECH 50 engine.," SAE Technical Paper 2001-01-1781, 2001, https://doi.org/10.4271/2001-01-1781.
- Motociclismo, Article, September 2000 issue
- Bell G. and Finucci C., “exhaust emissions sensitivities with direct injection on a 50cc scooter”, SAE paper 970365
- Dell'Orto SpA, Laboratori R & S, Prova No. 589 “rilievi di emissioni ECE47 (euro 1): Aprilia SR 50 DITECH”. 19/07/2000
- Aprilia S.p.A., User Manual: Aprilia SR 50