vendredi 27 avril 2012
CESA 2012 interview : Guillaume Devauchelle (Valeo) part 3
"Given the CO2 regulations in Europe and US for 2020 and beyond, it is now obvious for the automotive community that hybridization of powertrains is no longer an option. Hybrid means breeding together an Internal Combustion Engine (ICE) and an electrical motor. The electrical motor allows to recover kinetic energy during braking in the form of electricity which is stored in a battery and made available for the next acceleration where the electric motor will provide extra torque to the ICE which, in turn, will need less fuel.
The problem with the hybrids is that they use a powerful electric motor to allow significant range of electric drive. To do this a high voltage is needed, which turns the battery big and expensive. The battery is the main on-cost of an hybrid, and all of them today suffer from an overcost and overprice which limits their market penetration.
Valeo's affordable hybrid concept is streamlined by 2 main concepts: First, to turn an hybrid cheap, the main lever is to reduce the voltage to reduce the cost of the battery. This requires to limit the power of the electric machine. Second, to use the long experience in StopStart micro-hybrids systems (that Valeo invented) using cheap, alternator-based, electric motor. Extensive simulations have shown that limiting the power to 12 kW allows to save up to 10-15% of fuel on the European cycle while allowing a low 48V voltage system. Also, limiting the electric drive to take-off and some low speed cruise operations allows to have a reasonably small battery pack.
Valeo's affordable hybrid system consists then in a Belt-Driven Starter Generator with 12 kW peak power, inherited from our former StARS StopStart system, together with a small 300Wh 48V battery and a 48V-12V DC/DC converter. All together the cost of the system is halved compared to traditional hybrids. Vehicles have been built to demonstrate this "right sized" system with value-to-cost optimization and OEMs have all shown high interest for this solution in the past months. We have no doubt this will turn hybridization into a real mass-market, why we have tagged our system "Hybrid4All".