ALP-Piaggio Liberty 125 iget 4T-3V

(Demonstrator vehicle)

Introduction

Based on the air-cooled 125cc Piaggio Liberty, we have finishing a rolling demonstrator vehicle with ALP-supercharger. Beside several detail improvements regarding the ALP supercharger, the visual integration of the ALP components into the vehicle, was our primary focus. Further technical and physical considerations pointed out the position of the ALP-pump between rear wheel and exhaust gas silencer. The advantages of this ALP arrangement are:

  1. ALP-pump and exhaust gas tubes are combined with the silencer system into one unit
  2. Vehicle chassis, fairings, helmet storage volume (under the seat) remain completely unmodified
  3. The ALP is covered by the silencer system already at 70-80%
  4. The ALP-arrangement is suitable for all scooter propulsion with single swing arm (CVT) independent from the manufacturer
  5. Without any package problems larger ALP-systems for higher engine displacements can be positioned in this way

Running demonstrator vehicle“ ALP-Piaggio Liberty 125ccm” at the geographical center of the European community

Performance improvements

The air-cooled ALP-supercharged Piaggio engine (3V-iget) has arrived with its vigorous peak performance (14 hp) the level of the high revving naturally aspirated water-cooled four valve engines, but this on lower engine speed level. The ALP-engine offers with a maximum torque of 13,9 Nm in a wide range a surplus 10-20% compared to the four valve engines. Regarding the original factory engine the ALP-engine increased torque by 40% and performance by 30% at the best. Noise emissions are lightly higher than factory level due to the modified air box, necessary for a higher gas flow.

Reduction of fuel consumption and performance:

Additionally the ALP-vehicle is equipped with a longer final drive, lowered friction speed of the centrifugal clutch and modified variomatic transmission character to realize a real down speeding engine behavior. The engine works with stoichiometric air fuel mixture (AFR = 14,7) in all mapping points without thermal overstress. Especially under full load there is a large potential for fuel savings (and emissions) as visible in the subsequent diagram. For this comparative measurement the vehicle was driven on the roller performance tester under real conditions at constant velocities along the tractive resistance line.

The fuel consumption was tested in the field, consisting of 1/3 urban and 2/3 country roads. The ALP Liberty consumed 2,25 Lit/100km (44,5 km /Lit), where as the factory Liberty 2,7 Lit/100km (37km/Lit) required. The fuel savings are 17%!

Despite the significant down speeding the acceleration of the ALP-Liberty is much better compared to  the factory version. The top speed of the ALP-Liberty reaches 99 km/h and thus is 8 km/h faster than the factory-Liberty.

Conclusion:

  • The reduction of fuel consumption of the ALP-engine achieves 17%
  • With the ALP-supercharger common air-cooled engines touch or surpass the performance of expensive water-cooled naturally aspirated four valve engines
  • The excellent acceleration of the ALP-engine due to the high torque at medium speed range is generally not reachable with naturally aspirated engines
  • The top speed of the ALP-Liberty was increased up to 99 km/h, what means a significant improvement of security for the vehicle rider on non urban roads
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