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RACING WITH HYBRIDS PROPOSAL TO THE ESMSC Jean Jacques His, Ferrari Head of Powertrain Department 16/11/2010. This presentation has been prepared and discussed by the Powertrain Group, and then presented to the Environmentally Sustainable Motorsport Commission.
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RACING WITH HYBRIDS PROPOSAL TO THE ESMSC Jean Jacques His, Ferrari Head of Powertrain Department 16/11/2010
This presentation has been prepared and discussed by the Powertrain Group, and then presented to the Environmentally Sustainable Motorsport Commission. However, this work is still in progress. This presentation has not yet got the final approval from the ESMSC.
Hybrids, KERS…Definitions & General Comments • Hybrid powertrains : • In this paper, hybrid powertrains are any kind of powertrain in which instant power may come from different sources, one of them being an internal combustion engine. • Primary energy on board the vehicle comes from a single energy source (ie : one single fuel is supplied to one single reservoir). • Secondary power source(s) use energy which has been recovered and stored in some accumulator (electric, pneumatic, flywheel or else..) while the car is running. • Kinetic Energy Recovery System : • In this system, the energy recovered and stored in the accumulator is only kinetic energy. Recovery takes place only when slowing down / braking.
Impact of Hybrid Powertrains On fuel economy • Hybrid powertrains in homologation cycle : • Engine is used at very low load : high mechanical + pumping losses • Energy use ≈ 35 % inertia / 45 % rolling + aerodynamic + resistence / 20 % gearbox & ancillaries • Stop & Start : cut idle operation (≈ 10 % of fuel used in EU cycle) • Efficiency : best ≈ 35 % (240 g/KW.h); city conditions (low BMEP) < 20 % ! • Major improvements : Load Point Moving + pure electric drive in city cycle • Brake energy recovery is an additional benefit of the device • Improvement of homologated fuel economy with hybrid systems may reach ≈ 30 % on powerful premium which run at very low BMEP in the homologation cycle. • General use on the road : • On high speed / motorway, potential improvement with hybrid systems is much lower / ≈ zero (internal combustion engine is then used in optimum conditions) • Hybrid system (secondary power source) may be used as a booster
Load point moving Best engine efficiency achieved at ≈ full load (case below ≈ 14 bar BMEP / 3000 rpm)In most low speed or steady state conditions, engines are run at >> 350 g/kWh. increase BMEP : Energy Storage & Recovery Systems are the most radical solution !
Potential impact of KERS On fuel economy in race conditions • Racing with Kinetic Energy Recovery System, a best case from some basic assumptions : • perfect recovery system • no limitation on torque applied by KERS during braking • no limitation on electric motor duty cycle • car speed profile supposed to be same w / wo KERS • fuel saving proportional to the energy which has been recovered by KERS, fully independent of the thermal engine • Realistic assumptions would probably lead to ≈ 50 to 60 % of expected fuel savings below
Potential impact of KERSOn fuel economy in race conditions • Conclusion : • a perfect 60 kW Kinetic Energy Recovery System, with 100 % efficiency, would recover < 10 kW average power, equivalent to 3,4 l/hour of fuel • a perfect 60 kW Kinetic Energy Recovery System, with 100 % efficiency, would recover < 3 % of the energy provided by a current F1 engine in the same conditions • for the same lap time, a perfect 60 kW Kinetic Energy Recovery System, with no energy storage limitation, would provide less than 3 % of fuel consumption improvement on a current F1 car. • real world situation, with real world 60 kW KERS (not a perfect system), would provide less than 1,5 % fuel consumption improvement with same ICE engine for the same lap time.
Impact of Hybrid PowertrainsOn fuel economy • Potential performance of a “perfect” KERS system, three options : • If speed profile is left free, for same car and engine, adding a KERS will just improve performance and will not significantly change fuel consumption • If speed profile is left free, if Load Point Moving is allowed, engine average load will be increased and a perfect KERS system would improve performance but fuel consumption will increase … even if efficiency (BSFC) is improved. • If speed profile is kept the same, for a race track having 16 % of lap time spent with brakes on, a perfect KERS would save ≈ 0,06 l/hour of fuel per kW of KERS (3,4 litres / hour saved by a perfect 60 kW KERS… whatever the engine).
Would racing with hybrids help hybrids? • Main challenges for road hybrids, focus on : low speed operation • Load Point Moving & Electric Drive • Cut the cost • Cut the weight : improve specific energy of energy storage systems • Improve components efficiency • Main challenges for race hybrids, focus on : high speed operation • Booster • Weight : improve electric motor & energy storage system power to weight ratio • Improve components efficiency • Vehicle dynamics control when KERS is working • Cost of development • Cost of components (control the use of “exotic” materials) • Crash safety • synergies between racing and mainstream industry would benefit to the development of hybrid systems components
Racing with hybrids? • Racing with hybrids would mean : • for given car + engine configuration : speed profile defines power requirement. Race engine already working at full load, ie : best efficiency • extra power from KERS : booster, on top of engine power : improved performance for “same” fuel consumption (overtaking …) • fuel consumption to be improved only by substitution of ICE energy with lost energy recovery (braking, thermal losses..) : electric drive in pit lane ?? • 4WD potential with some systems (electric front axle) • vehicle dynamic control to be adressed (balance during braking) • increase of cost and weight
Racing with hybrids In top level categories • Manufacturer competition : • Racing with hybrids would help improving energy storage and motors (electric or else ..) technologies • Risk : development of exotic technologies • Would race hybrids be worth their cost : • Would racing with hybrid help the development of energy storage systems, which has been going strongly up to now with industrial competition ? • What impact on racing ? …. overtaking (KERS), pit lane with electric drive, … • What racing with hybrids would mean : • Racing technologies would remain (more) consistent with road going technologies • We have to understand whether electric drive to front wheels might be acceptable • We have to understand whether motorsport needs hybrids ….. • ….. and whether hybrid technology needs motorsport.
Privateers racing with hybrids? • Privateers racing with hybrids : • Sports & GT road cars with hybrid powertrains are coming on the market • Hybrid cars should be homologated • Critical issues : • Safety • Cost (keep SoC of batteries at an acceptable level…) • Control strategies (recover braking energy only, or accept LPM, driving aids ….) • Power : air restrictors control maximum ICE power, adding a booster might be conflicting with instant power control • GT racing : • GT racing has to face the hybrid issue • Current GT racing open to 2WD only
Next Steps with Hybrids? • Racing with hybrids : • Accept a limited improvement of fuel economy in race conditions ? • A solution targeting higher FE improvement in race remains to be found • Use recovered enegy for overtaking ? • Electric drive : use recovered energy in pit lane ?? • Accept 4WD in categories which do not allow it up to now ??? • Would hybrid cars be competitive against conventional cars ?? • … and would all this be worth the money ? • Top level racing : • KERS currently investigated for F1 • GT racing : • Save consistency and relevance with production cars • Define technical rules • Define homologation rules