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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