• Reduction of fuel and oil consumption:

Two litres per 100 km. Compared to tradition technologies, the Aprilia DITECH engine is able to reduce fuel consumption by 40% in the ECE47 drive cycle and up to 50% at constant speed. And more importantly, the impressive reduction in consumption is obtained while maintaining performance equal or superior to that of current best-in-class engines.

Aprilia DITECH exceeds the 50 km per litre mark. Traditional technologies offer, at best, around 29 kilometres for the same litre of fuel.

A four-stroke 50 cc engine, until now considered the lowest consumption engine, can achieve a reduction of upto 30% at most, but with considerably lower performance.

In addition to these surprising results, oil consumption is also reduced by 60% (from 85 cc per 100 km in a two-cycle with catalytic converter to 35 cc per 100 km with a DITECH engine). Not just considerable financial savings, but also greater convenience as the scooter needs filling with oil only during a full service. Thanks to the 1.6 litre capacity of the oil tank you can travel almost 4,500 km without having to top up the oil.

• Performance and driveabilty

With respect to a two-cycle with catalytic converter, the Aprilia DITECH offers considerably better acceleration, with performance over 100 km up by 15%, equivalent to a second and a half and a full two to three seconds with respect to a four-stroke.

The Aprilia DITECH is characterised not just by acceleration. It can boast a driveabilty second to none in the 50cc scooter class. At low RPM and low speed, the scooter is easier to ride, with more stable and regular combustion.

Aprilia DITECH guarantees consistently perfect starting at all temperatures.

• Lower pollutant emissions.

With respect to a traditional 50cc engine, the Aprilia DITECH reduces pollutant emissions by 80%. It not just conforms to EURO 1 standards without requiring use of a catalytic converter, but actually improves on them by 50%.

DITECH, a technological solution opening up a new era for engines, offering further margins for development. Aprilia is working on a further development which will enable DITECH technology to respect the future Euro 2 limits proposed for 2002 without requiring a catalytic converter or other devices. This is particularly important as the use of electronics will enable a Euro 1 vehicle to be converted to a Euro 2 vehicle at zero cost. An "insurance policy" for Aprilia, but also for the customer choosing DITECH who will not have to worry about future traffic restrictions in the knowledge that he will be able to move about freely without having to bear additional costs and that he possesses a vehicle able to hold its value on the second hand market.

To respect Euro 2 standards, a four-stroke engine will surely be fitted with a catalytic converter on the exhaust and most likely also a secondary air injection system necessary to reduce the high CO emissions of this type of engine. The engine cost will be again higher and performance dramatically reduced.

Unlike two or four stroke engines with catalytic converter, DITECH maintains the long-term efficiency of the system without requiring further maintenance or the replacement of components.

• Longer life, reliability and electronic control

The APRILIA DITECH engine has a considerably longer working life than a traditional 50cc engine, firstly thanks to the injection of oil, undiluted by the fuel entering the crankcase, enabling it to act efficiently on the mechanical components. Electronic control of the oil pump guarantees optimum lubrication.

Highly reliable injection system guaranteed by many of the components used, for example, the fuel injector, deriving from the automotive sector and thus validated and produced in runs of millions.

The DITECH engine is completely electronically controlled by an Electonic Control Unit (ECU) providing constant automatic diagnosis of all components and real time warning of malfunction. The system provides description of anomalies found in a particular component, reducing the repair times and costs. Services and tuning are simple thanks to the computerised diagnosis system.

• Comfort

Thanks to DITECH, the emission of exhaust smoke is eliminated, as is emission of unburnt oil particles which settle on the rider’s garments and produce an unpleasant smell.

A new way of using the scooter, without the irritation of topping up the oil, dirty spark plug, flooded engine or difficult cold starting.

APRILIA DITECH: development phases

December 1998: Aprilia became the first company in the world to present an electronic direct injection (DITECH) engine.

April 1999: Aprilia became the first company in Italy to gain approval for a vehicle with a two-cycle electronic direct injection engine.

December 1999: Aprilia concluded the experimental and testing phase of the DITECH project.

2000: Aprilia is ready for large scale production of the DITECH engine.

THE ELECTRONIC DIRECT INJECTION APRILIA DITECH

The APRILIA DITECH is an environmentally friendly engine with extremely low consumption, high specific power and high performance. Small and light, it is both technologically advanced and simple in its construction. It is also very reliable thanks to the extensive use of electronic control of engine function.

OPERATION

DITECH is the perfect engine for small capacity scooters.

One of the great innovations of the DITECH engine is the fact that fuel is no longer mixed with the lubricating crankcase oil, but injected directly into the combustion chamber. The whole process is electronically controlled by sensors connected to the ECU.

• In a traditional two-cycle engine, the combustion chamber is scavenged with a fuel/air mixture. A considerable quantity of unburnt fuel and oil therefore "short circuits" the combustion chamber to the exhaust and is discharged into the environment (greater pollution and higher consumption). In the Aprilia DITECH system, the chamber is scavenged with air only. The fuel is injected directly into the chamber only when the exhaust ports are closed.

• With the DITECH system, ignition of the mixture is guaranteed with each piston stroke, thus eliminating the misfire effect with unburnt petrol and oil introduced directly into the exhaust. Perfect combustion is guaranteed by a direct charge injector enabling a stratified charge. Normally the mixture consists of 1 part fuel to 14 parts air. With DITECH, a richer mixture can be used only in the part of the combustion chamber nearest to the plug, controlling propagation even in areas where the mixture is so lean as to be at the limit of ignition. With DITECH, even at full gas the engine runs a lean air/fuel mixture. Under partial throttle conditions, it functions perfectly at 30 : 1 air/fuel ratio and at idle the ratio reaches 50:1.

• DITECH uses sophisticated electronic pumps to deliver the petrol and oil. All engine phases are controlled by sensors which continuously send information to the electronic control unit. Constant automatic diagnosis of the system enables the ECU to regulate and optimise operation of the engine.

ELEMENTS AND OPERATION OF THE APRILIA DITECH SYSTEM

ELECTRONIC PETROL PUMP (B) – Sends fuel from the tank to the air fuel rail, but this is not a traditional pump, but an highly innovative device working at pressure of 6 to 8 bars. Despite its high performance, the electrical absorption of the pump is very low, in comparison with a traditional pump.

AIR FUEL RAIL (G) - This consists of three separate components:

• Fuel injector (G2): this controls the fuel dosage by injecting precise quantities into the direct injector interface. The reliability of this element is fundamental. This is why a type used in the car sector (EFI) was chosen. Already produced for some time in millions and tested under all conditions, it guarantees maximum reliability and operating precision.

• Direct injector: this is perhaps the fundamental element of the system. Controlled by the ECU (G7), its task is to mix the petrol coming from the fuel injector with the compressed air and use the "force" of this air/fuel charge (5 bars) to atomise the fuel particles as it enters the combustion chamber (G1). To get an idea of the precision required by this component, a car "port" injection system (EFI) can atomise fuel particles to 50 microns (Sauter Mean Diameter SMD measurement) and a direct injection diesel engine achieves a size of 20-30 microns. Particle atomisation in the Aprilia DITECH system is 8 microns (SMD) with an evaporation time of less than one millisecond.

• Pressure regulator (G6): the fuel injector functions thanks to a difference in pressure between the petrol it contains and the compressed air circuit. The regulator guarantees pressure stability with precise fuel injector valve opening times to inject the precise quantity required.

COMPRESSOR (D) - The 5 bar compressor sends the compressed air to the direct injector. The compressor serves to atomise the charge and not to supercharge the engine. The compressor is controlled by an eccentric cam on the crankshaft. This technical solution avoids having to use an external compressor with additional tubes, independent lubrication and filtered air intake circuits, elements that would have complicated the component.

ELECTRONIC OIL PUMP (A) - The oil pump is a solenoid device driven electronically to guarantee maximum operating precision. The DITECH system guarantees optimum oil quantities for engine lubrication over the complete engine operating range.

IGNITION/COIL (E) the DITECH engine requires powerful, precise and reliable ignition, the only way to guarantee complete combustion, engine efficiency and a reduction in unburnt hydrocarbons in the exhaust gases.

ELECTRONIC CONTROL UNIT (ECU) (F) - The soul of the system, this extremely compact ECU controls and manages every aspect of the engine.

It regulates:

• injection quantities and timing;

• ignition timing;

• the fuel pump;

• the oil pump;

• continuous automatic diagnosis of all the electronic components in the system with warning of operating anomalies detected.

The control unit regulates all functions, processing information on revolutions and throttle opening in real time.

THROTTLE BODY (C) - in DITECH, the traditional throttle body regulating air intake and controlled by the throttle cable has an additional feature. It is fitted with an electronic TPS (Throttle Position Sensor) which reads the opening of the throttle and transmits the information to the electronic control unit.

TECHNOLOGICAL PARTNERS IN THE APRILIA DITECH SYSTEM

Experience, intuition, innovation and research also mean the ability to identify the right partners to explore new roads and try out avant-garde solutions.

Collaboration with the best and most highly qualified suppliers is a fundamental element in the network structure of a company such as Aprilia. Once again, this has led the Italian motorcycle company to choose the best prepared and most innovative available, hitting the bull’s eye with a fundamental chapter in the story of urban mobility on two wheels - the DITECH system.

ORBITAL ENGINE COMPANY is the technological partner responsible for developing the OCP (Orbital Combustion Process) technology on which the DITECH system is based.

SIEMENS AUTOMOTIVE is the leading world producer of injection systems.

SYNERJECT LLC, formed by the partnership between these two great names, is the company that is charged with supply the system components.