It is not “mild” nor “full”. Stellantis’ new hybrid powertrain is somewhere in between that defies these two definitions, taking something from both. Definitions which, however, are only commercial, given that on the registration certificate these two hybrid systems are defined in the same way. Thus the 1.5 e-Hybrid is already available on various Fiat (500X and Tipo), Jeep (Compass and
Renegade) and Alfa Romeo, in this case also in a more powerful variant that has 160 HP instead of 130 HP (the maximum torque is 240 Nm).
In any case, the concept behind this hybrid engine is simplicity: the 1.5 4-cylinder is combined with a 7-speed double clutch gearbox, inside which is the electric motor that provides another 20 HP. Then there are the 48 Volt electrical system, the BSG starter-generator and the 0.8 kWh lithium-ion battery. The latter weighs 13.5 kg and has a volume of 11 liters, thanks to which it has been positioned inside the central tunnel at the height of the front seats.
Leaving the technicalities aside, it is a much simpler scheme than that of “full hybrid” systems and only slightly more complex than a “mild hybrid”. Furthermore, during the WLTP homologation, it allows you to drive for almost half the time with the thermal part off, while consumption is on average 11% lower than the 1.3 T4 turbofan.
Not a striking difference but, as we said, it is a scheme that makes simplicity its strong point. It is designed to start the car with the thermal engine off and to make it intervene only over 20 km / h; in this way the city queues, the “stop and go” and the maneuvers are carried out in silence. The 4-cylinder then switches off in all those situations where the pace is constant and the gas pedal is only touched. Instead, every time the brake is pressed, the electric motor recovers energy and sends it to the battery.
The battery is managed by the software in such a way as to always gravitate around 50% of the charge, so as to have enough energy to push the car, but also enough space to store new one. The second aspect is fundamental, because unlike what happens in “full hybrids”, the petrol engine never generates current for the accumulators. The latter is also equipped with valuable solutions, such as the all-aluminum construction, the distribution with double phase variator and the 350 bar high-pressure direct injection system, which until now had only been seen on Ferrari engines. The last relevant technical note concerns the operating cycle which is not the classic Otto, but the Miller – the compression phase is shorter than the expansion phase, to increase the energy that derives from the pressure generated by combustion – for a compression ratio of 12.5: 1, two points higher than that of the 1.3 T4.