How 48V technology can reduce fuel consumption by 25%

April 22, 2016 // By Christoph Hammerschmidt
Already with its Gasoline Technology Car I (GTC I), automotive suppliers Continental and Schaeffler managed to reduce fuel consumption by 17%. At the Vienna Motor Symposium, these two companies introduced the GTCI II – a feasibility study, devices in close collaboration with Ford motor company that reduces fuel consumption by another 8 percent points to reach the mark of 25%. A decisive role in both cases plays the 48V split-voltage technology.

The reference point for both vehicles in terms of fuel consumption was a series-built Ford Focus, tested according to the New European Driving Cycle (NEDC). This vehicle already was equipped with a very efficient turbocharged three-cylinder gasoline engine. The GTC II demonstrates the potential of intelligent 48V hybridisation of the newest generation. The most striking difference between GTC I and GTC II is that the electric motor/generator is integrated between internal combustion engine and transmission, the so-called P2 achitecture. An additional element in this configuration is the electric clutch that optimises manual gear switching. This electrified clutch enables the vehicle to get driving from zero speed solely powered by the electric motor, electric stop-and-go operation as well as recuperation mode almost down to zero speed, said Peter Guzmer, R&D manager at mechatronics company Schaeffler.


The 48V P2 hybrid architecture enables particularly compact hybrid configurations

 

Both GTC generations are based on an intelligent interplay between all elements in the powertrain. The hybrid operating strategies are utilising a comprehensive integration approach makes the whole more than just the sum its parts. However, the GTC II exploits the potential of the 48V technology at a higher degree than its predecessor. For instance, the electric motor is coupled to the system through a belt and attacks between combustion engine and transmission. Two clutches, one in front of the belt drive and one behind it, make it possible to completely separate the combustion engine from the powertrain and to operate the electric motor independently. This enables “electric soaring”, an operation mode runs under low partial load at constant speed and likewise electric stop-and-go operation, for instance in traffic congestions. This operating mode significantly saves fuel because the combustion engine is “out of the loop” and can be completely switched off. Since there is also no drag torque, it is possible to utilise significantly more kinetic energy for recuperation. In addition, operational mode enables better