eSAAB Series Hybrid Technolgy and Rational by yurtgc548

VIEWS: 1 PAGES: 14

									  eSAAB Series Hybrid
Technology and Rational
       Why Electric, Why Hybrid?
• Modern society runs on energy, most of which is
  derived from the burning of hydrocarbon fuels.
• This energy source is not sustainable for a number of
  reasons: Environmental, Economic, Political, Supply.
• Fixed energy needs can utilize solar, nuclear, wind, etc
  for alternative power sources.
• Transportation can not use these alternative power
  sources as easily. These other sources can be used
  when energy is stored electrically in batteries.
• Electric vehicles practicality can be enhanced by using
  electric drives operated in hybrid configuration with
  Internal Combustion Engines (ICEs).
 How is an Electric vehicle better than
    an ICE (status quo) vehicle?
• Electric motors are very efficient over a broad
  Torque and RPM range (simplicity and versatility).
• Electric motors need less if any gearing and have
  no need of torque converters or clutches.
• Electric motors can facilitate regenerative braking
  where braking is used to charge batteries.
• Batteries can be charged from efficient stationary
  sources. Solar power, Even 60% efficient coal or
  gas fired power plants.
   Electric vehicles are an old idea,
                 what’s
 new that makes them practical now?
• Early electric vehicles were very successful,
  however ICE vehicles came to offer more power
  and much greater range as ICE technology
  improved. Battery and electronics technology did
  not advance as fast as ICE technology.
• The battery storage system of 1920 electrics
  limited the range and power of vehicles. New
  technology can store 20 times the energy.
• Early electric control systems were wasteful.
  Modern electronics allow amazingly efficient
  control of motors and batteries.
            Why Hybrid Electric – ICE
             versus Electric only?
• Even with advances in battery and electronics technology, a
  conventional size vehicle with an electric only drive achieves a
  limited 20-40 mile range when driven above 45mph.
• Electric storage (battery) technology needs to improve another 5
  fold or complementary power source needs to be placed on board.
• The coupling of an ICE with an electric drive as a hybrid is a good
  compromise that yields ICE range and Electric drive efficiency.
• The simplest hybrid designs have the electric drive do the work at
  low speed/power and short distances, while the ICE does the work
  at high speed/power over longer distances.
• Complex hybrid designs attempt to optimize the operating range of
  the ICE, Either by only operating the ICE at its peak efficiency
  points, or by using parallel drive technology to keep the ICE as close
  as possible to its peak efficiency.
   I see hybrids on the road already, Is
    there any room for improvement?
Parallel Hybrids are the type      A Series Hybrid is proposed
common on the road today.          where the wheels are driven
These systems have the             by the electric drive only. The
following characteristics:         ICE charges batteries only:
•Small electric motor              •Large electric motor
•80% size ICE relative to status   •ICE 50% or smaller. Sized for
quo.                               average load.
•Complex mechanical drive          •Simple mechanical drive
•Reasonable efficiency gain        •Highest efficiency
•Comparable city/highway           •Comparable city/highway
performance relative to status     performance relative to status
quo. Low efficiency gains at       quo but highway speed
highway speeds.                    duration limited.
          How can an ICE operate more
           efficiently within a hybrid?
Current ICE technology is very evolved and amazingly advanced, but it suffers greatly
from a concept called, “power factor”.
•A Honda ICE generator with a 6.2 gal fuel tank(model EM6500S) specifications state a
10.4 hour run time for 3250 watt load and a 6.9 hour run time for 6500 watt load. This
means the same amount of fuel produces 33.8Kwh at half load but 44.85Kwh at full
load. When fully loaded, the generator is 32.7% more efficient.
•Vehicles experience a similar scenario. An ICE vehicle may get 23.6 mpg on the
highway at 70 mph, yet only get 15.4 mpg in the city at 35 mph. In terms of load
demand, the vehicle should do much worse at high speed due to wind drag. Almost 4
times the power is required to do twice the speed, yet slow speeds still produce better
fuel efficiency. The power factor losses of a lightly loaded ICE power plant makes the
vehicle more efficient at higher speed.
•Hybrids can use the electric drive and battery storage to “decouple” the ICE from the
actual momentary load requirements of the vehicle. This means the ICE can spend a
lot of time off, and then only run under conditions that better utilize its power factor.
            So what are the efficiency
          improvements from a hybrid?
•   Pluggable hybrids have a big gain for the duration they run entirely on battery.
    Modern power grid plants use multi-stage steam drives that get almost 60% of the
    energy out of their fuel. Even accounting for transmission losses, charging
    batteries from the grid is about 40% efficient. A good ICE in a car can only hope for
    15% efficiency. Thus, battery operation is 267% more efficient than the status quo.
    (and a lot cheaper to operate too)
•   When the ICE in a hybrid does run, it operates at near its full power factor. In the
    case of a series hybrid, this means a 30% increase in efficiency for highway driving
    and a 60% or more increase in efficiency for low speed city driving, approximately.
•   When in the city, a hybrid typically has regenerative braking which can recover up
    to 60% of the kinetic energy of the vehicle at every stop. This can produce an
    approximate 35% gain in efficiency for typical city driving.
•   The cooling requirement for hybrids is reduced (evidence of increased efficiency),
    thus grill fronts of cars can be made more aerodynamic. This will produce an
    efficiency gain at speed of 10% to 40% depending upon the profile of the vehicle.
     What should a series hybrid owner
      expect to see at the bottom line
There are many variables to consider, but at least 4 vectors of savings can suggest the following.
•A hybrid owner who operates his vehicle on battery 90% of the time (30 miles or less before charges)
can expect to use 42% of fuel normally used. If the charging source is solar or wind, the carbon usage is
near zero. Given a price of electricity at $0.08 per Kwh and gasolene at $3.00 per gal, the same owner
will spend 1.6% as much to operate the vehicle. If the owner spends $20 per week on gas, he will
instead spend around $0.32 per week on electricity. In yearly terms, $1040 per year versus $16.64
electric or an annual savings of $1023.36.
•A hybrid owner who operates his vehicle on battery only 10% of the time because of longer driving
between charges will have much less benefit. This driver will likely use 78% as much fuel. A small
amount of his transport energy comes from electric and so a small additional reduction in carbon use
may be realized by solar or wind sources. Since the majority of fuel is gasolene, cost savings will follow
fuel savings. A $60 per week cost for an ICE only becomes $46.8 per week for the hybrid. In yearly
terms, $3120 per year versus $2433 hybrid or an annual savings of $686.40.
•Assuming an additional cost per vehicle of $8000.00 for a hybrid (at $3.00 per gallon), it takes almost 8
years to pay for the additional expense of a hybrid versus a status quo ICE. It takes almost 12 years for
the high mileage operator to realize savings equal to the hybrid expense. However, if fuel doubles in
cost, which is likely within a few years, the low miles hybrid owner will pay for his vehicle in two years
and the high miler in as few as 5 years. The carbon reduction for the low mile driver, even with a coal
power source, is huge reducing his carbon by over half. The high mile driver sees almost a one fourth
reduction in carbon as well.
•Politically speaking, the low mileage driver gets almost all of his transportation energy domestically,
while the high mileage driver reduces imported oil use by almost 25%.
                The Roles of Hybrids
The previous example illustrates the characteristics of Hybrids and the roles
for which they are well suited.

•Short trip drivers. A hybrid for driving kids around, groceries runs, etc is a
good match.
•Delivery vehicles. Vehicles with many starts and stops will benefit greatly.
The high utilization of a commercial vehicle will shorten the payback to a few
years making a hybrid a financial must-buy for delivery services.
•Long Haul, high mileage vehicles. This role does not see the greatest relative
efficiency gain, however the high utilization and high fuel expense relative to
vehicle cost make the low 25% reduction a big incentive for a hybrid vehicle.
Bid heavy vehicles could benefit from this most with payoff times as low as
one year. Unfortunately, there are no producers of this type of OTR vehicle
yet. Hopefully, industry will step up and create this vehicle soon.
 The Challenges and Opportunities for
           Hybrid Vehicles
The case for the need of hybrid vehicles has been made, both by this author and
others. However hybrid vehicles are not an evolved technology yet, and there are
many challenges to overcome, and opportunities to seize to improve this technology.

•The battery systems remain a big challenge. Power densities are just now at a
feasible level. A 2x increase in battery power density would make hybrids more
versatile while keeping payload volume and weight competitive with the status quo.
Also, a 2x or greater price reduction of batteries will drive the hybrid costs down to
the point that additional cost of a hybrid will be made up in a few years.
•The motor and generator form factors used in hybrids are suited for industrial use. Re
-design of these elements for purpose use in vehicles would allow for greater range
and efficiency in hybrid vehicles. This would make the performance limitations of
hybrid and electric vehicles non-existent and would even give hybrid vehicles a
performance advantage over traditional ICE vehicles.
•Infrastructure and taxation should be changed to favor the addition of hybrid vehicles
or purpose owned vehicles for short distance. Current lack of charging stations make
most electric only or hybrids unattractive as a general purpose sole vehicle, while tax
and insurance regulations make owning an additional vehicle for short distance
transportation unaffordable.
    Where does eSAAB fit into this?
The preceding discussion resulted in the following design criteria for the eSAAB:
•The conversion cost must be held below $15000 per car. An older car with current or
anticipated repair/restoration driveline costs of $2000 or more are ideal candidates.
•The battery cost must be minimal (5 to 10 minutes full power operation). Battery is
primarily for low speed short run commuting or ICE load decoupling.
•The performance of the conversion must yield a vehicle with performance on par
with the ICE only version of the car. (large electric motor).
•Driveline modification must be simple and reliable, thus a series hybrid is the only
option. The design must reuse as much of the existing car components as possible.
•Small on-board generator must extend the low speed range to a minimum of 100
miles per charge for speeds of 45 mph or lower.
•A highway option must be available to allow this vehicle to be a sole, general purpose
vehicle. eSAAB proposes a special trailer device which houses sufficient generator
capacity for sustained 65 mph driving. The trailer will also have storage area for
increased utility and have linkage improvements to improve trailer handling.
            What is next for eSAAB
• The eSAAB project is currently working on its first prototype to be
  rolled out at the 2011 SAAB owner’s convention. This design is a
  conversion on a classic 1972 SAAB 99. This conversion will feature a
  30hp (90hp max) 3 phase AC induction motor coupled with a 5,500
  watt gas generator via a 5.5Kwh LiFePO4 battery pack.
• Soon after completion of the first prototype a SAAB 900 (classic
  style) will be converted with a similar motor, battery, and
  generator combination.
• Enhancements to the system are already on the drawing board, for
  the ICE generator. Specifically TEG heat recovery for added
  generation capacity for the same amount of fuel. Miller cycle
  modifications to the ICE cam shaft coupled with increased RPM
  operation is also under consideration. Taken together, these
  enhancements promise an additional 10% to 60% increase in fuel
  economy of the ICE generator.
         How can I be involved
• Once the initial prototype is completed, eSAAB
  will be looking for other founding customers to
  order conversions.
• We love publicity and welcome open discussion.
  Feel free to talk about what we are doing and
  boost for us in your community.
• We will be taking on private investors in the last
  quarter of 2011. Talk with us then about
  investing the eSAAB.
• Contact us at eSAAB@proteanlogic.com or call us
  at 303 828 9156.

								
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