At ninety years old, Luciano Tonini has amazed the automotive engineering world with a surprising innovation in the internal combustion engine. In an era where electrification seems to dominate the future of mobility, Tonini has proven that there is still room to improve the efficiency of traditional combustion engines, reducing both fuel consumption and environmental impact.
The Geometric Revolution of the Engine
The idea behind this modification consists of shifting the crankshaft pin of a traditional engine to the 90° position and, using the piston’s pivot point at mid-stroke, rotating the cylinder counterclockwise by an optimal angle for operation. After various tests, a tilt of about 12° was chosen. This new geometric configuration creates an “X” arrangement between the traditional axis and the new cylinder axis, with significant effects on the engine dynamics.
The consequences of this modification are remarkable: the Top Dead Center (TDC) is advanced by more than 3 degrees, while the Bottom Dead Center (BDC) is delayed by about 4 degrees. This results in a longer duration of the intake and expansion phases, increasing from 180° to 187°, and a reduction of the compression and exhaust phases to about 173°.
The Advantages of the New Configuration
Tonini’s geometric innovation brings several benefits:
- Better combustion of the air/fuel mixture, thanks to the longer active phase, positively impacting the reduction of polluting emissions.
- Increased cylinder filling, due to the extended intake phase, optimizing the engine’s volumetric efficiency.
- Reduced lateral thrust on the connecting rod, thanks to a more favorable expansion angle, improving engine reliability and longevity.
Tests on Honda 125 4T Engines
To verify the effectiveness of the modification, Tonini and his team tested the system on two Honda 125 4T motorcycles from the 1980s, one modified and the other original for comparison. The tests, conducted by the “101 srl” Testing Center in Rimini and on the test benches of the Naldi Terzo Workshop in Predappio, showed a clear improvement in the performance of the modified engine in terms of both power and torque.
This project demonstrates that innovation in internal combustion engines has not yet reached its limits. Thanks to Luciano Tonini’s passion and ingenuity, a simple geometric modification has resulted in a more efficient and less impactful engine, making a valuable contribution toward a more sustainable future.