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
Single seater
Average circuit
Braking / lap time (typical lap : 90 sec, brakes on : 17 sec)
Braking power recovery (kW)
16%
60
Kinetic Energy Recovery System overall efficiency
100%
Engine + gearbox overall efficiency
31%
Average power recovery from KERS (kW)
9,6
If above power would have to be supplied by ICE engine, this
power would increase fuel consumption by (l/h) ………………
3,40
Potential impact of KERS
On 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 Powertrains
On 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