JMU AFV Lab Blog

This interesting invention by Dean Kamen, the inventor of the Segway, was in today’s edition of gizmag news.  He has developed and patented a unique motor scooter which uses a Stirling engine to charge a battery to run an electric motor.  Now, the Stirling engine has been around a long time.  I suppose it can be called an external combustion engine, as it derives its power from heat generated somewhere other than in the chamber that drives the piston which provides the motion needed to produce power.  Dan Drumheller here at the AFV Lab has built a working model of a Stirling engine.  He had it running here one day with a candle flame as a source of heat.  Check it out at: http://www.gizmag.com/dean-kamen-segway-hybrid-scooter/12096/ Ever since Dan had that engine here in the lab, I have thought about it and wondered if a Stirling engine be used for something like this.  Seems it can!

Source: http://www.gizmag.com/dean-kamen-segway-hybrid-scooter/12096/

Dean Kamen developing eco hybrid that will run on anything that burns

By Ben Purvis

20:19 June 28, 2009 PDT

Dean Kamen – the multimillionaire inventor behind the Segway personal transporter – is well down the road in the development of a new bike that combines electric power and a radical generator which will allow it to burn almost any fuel.

Built around a fairly conventional battery and electric motor combination to provide the drive to the wheel, something Kamen’s experience with the much-hyped Segway makes relatively easy, the radical part of the design is the inclusion of a Stirling engine to recharge the bike’s battery pack. Based on technology that pre-dates the internal combustion engine by nearly a century, the Stirling engine is closer in concept to a steam engine, using external combustion, and without the need for a fuel that can be injected and burned incredibly fast inside a normal engine’s combustion chamber, it can run on virtually anything that burns – opening the door to easily renewable fuels rather than relying on dwindling fossil fuel supplies.

Although the prototype bike has yet to be shown in public, unlike Kamen’s Stirling-engined car which has been demonstrated several times, Kamen himself is understood to have been using the prototype to zip around his own estate.

As revealed in Kamen’s own patent for the technology, the bike looks like a conventional scooter, with the Stirling engine and its fuel tank mounted under the seat, a rechargeable battery pack in the floor and a radiator in the front fairing. Although the Stirling engine’s low output – one this size is unlikely to make any more than 5bhp – means it can’t give the bike much performance on its own, it’s able to keep the battery topped up by continuing to supply electricity even when you’re not moving. The energy reserves in the battery can be used when more power is needed. And as the Stirling engine could be left running at low speed even when the bike is parked, the battery would never be likely to go flat.

Kamen has already sunk more than $50 million into his development of Stirling engine technology, using the idea for everything from bikes to cars and even to water-purifiers to be used in the developing world.

What’s a Stirling engine?

Although the idea for Stirling engines has been around since 1816, they’ve never been mass produced so the concept is still quite unfamiliar.

Like a steam engine or internal combustion engine, Stirling engines use pistons to turn a crankshaft, but unlike the alternatives they have no valves as no gas ever enters or leaves the cylinders. Instead, the idea is to use the fact that gas expands when it’s hot and contracts when it’s cool to move the pistons. Although there are several variations on the theme, Kamen’s design uses a design known as a two-piston Stirling engine which has a power piston and a displacer piston.

The cylinder of the power piston is heated from outside, making the gas – normally helium – inside the cylinder expand, moving the power piston and giving a power stroke to the crankshaft.

The flywheel weight on the crankshaft keeps the rotation going, moving the power piston back, on what would be the exhaust stroke of a four-stroke internal combustion engine. But rather than sending the expanded gas out into the atmosphere, it’s sent through a transfer port into the second “displacer” cylinder, which has its own piston – at this stage moving down its stroke. Unlike the power cylinder, the displacer cylinder is cooled, so once the gas is moved there it contracts.

Again, flywheel momentum keeps the engine going as the displacer piston returns up its bore, forcing the gas – now cool – back through the transfer port into the power cylinder, where it’s heated for the cycle to begin again.

Disadvantages:

Compared to an internal combustion engine, Stirling engines give out relatively little power and torque compared to their size and weight, they take time to warm up and start working properly and they can’t react quickly to a throttle control – which explains why they never replaced either the steam engine (even slower to warm up, but more powerful) or the internal combustion engine (very powerful, no warm-up time and fast throttle response). But by linking a Stirling engine to a battery and electric motor, the disadvantages start to drop away.

Advantages:

Because they don’t need internal combustion, where you need a highly volatile, liquid fuel to burn at incredibly high speed inside the cylinders, they can run on almost anything and use high-efficiency burners that completely use whatever fuel is being used. With many of the emissions problems from internal combustion engines relating to “unburned hydrocarbons”, Stirling engines can be cleaner.

Think of them like the wood burners that are becoming increasingly popular in homes, which are able to chuck out huge amounts of heat from slow-burning, natural fuel. Just like them, the Stirling engine’s ability to completely burn whatever fuel is being used, making the most of the potential power tucked away inside that fuel.

They also use the heat from burning fuel very efficiently. In an internal combustion engine, heat is a problem and engineers go to huge efforts to get rid of it, Stirling engines use the heat itself to create power.

And by running cleanly and at a constant speed, they’re perfect for being linked to a generator to supply electricity.

Has the Stirling engine come of age?

Kamen isn’t the only person to have leapt onto the idea of Stirling engines as the world looks around for cheap, sustainable and clean energy, although with several years’ development under his belt and more than $50 million invested he’s got a head start.

Honda has also been looking at the idea, not so much as a way of powering an entire vehicle but as a way of extracting more power from a conventional internal combustion engine. The firm has patented concepts revolving around small Stirling engines bolted to the exhaust system of a normal engine, using the heat from the exhaust as “free” power for the Stirling engine, which could then be used instead of a power-sapping alternator to power a car’s (or bike’s) electrical systems.

Motorsport experts Prodrive have also been helping develop a Stirling engine, not for a vehicle but for your home. The idea is to create a machine roughly the size of a tumble drier that will both heat a house and provide all its electrical needs, all using the Stirling engine concept.

Other new applications for the technology include an autonomous robot for the US military, which is being designed around a Stirling engine which allows it to effectively “eat” by feeding itself wood or leaves, creating a machine that can remain active for years on end without needing to be recharged, while on the other side of the world, in Taiwan, tiny Stirling engines are being developed to run off the heat from computer chips, providing power for a cooling fan.

source: http://www.gizmag.com/dean-kamen-segway-hybrid-scooter/12096/

These two items from gizmag and AutoblogGreen came to my attention recently.

The first, immediately below, from gizmag, introduces a novel system for an electric bicycle that uses both a hub mounted motor and a separate hub mounted battery on the other wheel.  This struck me as quite an interesting idea.  Having never ridden an electric bicycle of any kind, I can only speak from what I suppose to be the case.  With that caveat, I have always thought that the battery pack on any electric bicycle I have seen heretofore was mounted much too high for stability.  It seemed to me they were all mounted up on the top frame tube or on the down tube coming down from the fork bearing tube.  Of necessity, they had to be high so not to interfere with the riders legs when pedaling.  Having the battery mounted in the hub would seem to me to make for a lower center of gravity and, thus, a more stable bike.  Having the probable weight distribution close to 50/50 would have to make for a better handling bike, too.

Even though it’s dated earlier, the second item, from AutoblogGreen, initially fascinated me, as it combines motor, battery, control system, and charger in one hub.  It also adds a Bluetooth wireless throttle control, too.  Talk about state of the art, this concept has all the bells and whistles.  Then I started really analyzing it and I kind of lost my initial enthusiasm.  I can’t help but think that all that weight biased to one end or the other would negatively affect handling.  I also can’t see how they are going to get a big enough battery in that hub to deliver the performance they claim.  I suppose the bluetooth solves the problem of wiring a control on the handlebar to the wheel, but I can’t help but think it’s overkill.  It appears to me to be a solution in search of a problem.

Sources:  http://www.gizmag.com/e-electric-bicycle-electric-motion/11059/ and http://www.autobloggreen.com/2009/02/19/mit-greenwheel-simply-an-electric-bicycle-revolution/

February 23, 2009 With the increasing popularity of the electrically assisted pushbike we are starting to see some innovative designs hit the market. While hub motors are the number one solution for mounting the electric motor within a bike frame, either in the front or rear wheel, mounting the battery pack and motor drive electronics has remained a challenge when taking into consideration practically and aesthetics. The folks at Electric Motion Systems think they have the answer with a combination of a 750 watt rear wheel mounted hub motor with built-in motor drive electronics paired with a battery pack mounted in the front wheel hub.

e-electric bicycle

The E+ Electric Bike is available in six styles of bike that are all a variation on a hard-tail mountain bike. The E+ comes standard with a 750 watt BLDC rear hub motor but there is a high torque 85 Nm 1kw hub motor as an upgrade option. Both hub motors have built in inverters so there’s one less box to find mounting space on the bike frame for. The front hub mounted battery pack is something we’ve never seen before on an e-bike. The internal layout is very similar to a hub motor with the stationary inner structure (called the stator) attached to the axle while the outer housing is attached to the rim via spokes and rotates as part of the wheel. Thirty NiMH battery cells are arranged in six groups of five cells arranged in a polygon layout parallel to the axle and mounted on the stator. The battery pack puts out 36 volts at 9 amp hour giving a battery capacity of 324 watt hour. (0.324kw/hr). No electric only range is quoted as this is very dependent on terrain, how much you pedal and the amount of regeneration possible but each battery charge should give between 20 and 40 miles (32 – 64 km). A full charge from a 110v wall socket will take four to six hours and cost about $0.03.

The E+ has a handlbar mounted LCD display where the rider can select 19 different cycling modes that range from full electric to pedal only modes. One of the E+ modes offers to let you set the cycling mode for increased resistance to give you a greater workout even if there are no hills in sight. While this could well be a useful feature, it also highlights one of the side effects of BLDC hub motors - they do not freewheel. Because a BLDC hub motor contains permanent magnets even when no power is applied there is still magnetic attraction between the magnets and the poles on the stator meaning there is always cogging resistance. The company says this should only be a problem with a flat battery on extended flat surface riding, as with any kind of undulation the motor will regenerate on the down hills just enough to provide power assistance up the next hill.

The LCD-display also shows speed, distance traveled, battery capacity, cruise control option, and 19 cycling modes. It also displays trip-specific data such as distance of trip, duration, and average speeds. Pocket-sized and removable for safe and easy storage, when the display is removed, the battery is disabled and the motor is put into full resistance mode, making pedaling virtually impossible. This unit has backlighting (0-100%) and automatically adjusts the contrast of display depending on outdoor conditions.

The Electric Motion Systems E+ Cruiser and E+ Mountain Bike cost USD$3,495.

One definition of the word elegant is “to be gracefully concise and simple.” In the future, the dictionary just might include the GreenWheel as a product that illustrates this principle perfectly. From the MIT Smartcities team that gave us the stackable cars concept and the RoboScooter (still a go), comes a wheel that can turn an ordinary bicycle into a very desirable electric one in an easy, cost effective manner. Enclosing a motor, A123 Systems batteries and a generator into a small aluminum pancake hub, the GreenWheel can give you up to 25 miles of propulsion, or much more if you don’t mind pedaling. Unlike conversions kits from the past, it forgoes running wires the length of your bike by incorporating the magic of bluetooth to control the twist-throttle.

Over a dozen different configurations of the GreenWheel are scheduled to be tried and tested by a variety of cyclists this spring. Once the the team analyzes their feedback, an ultimate configuration of power, speed and cost will be settled on and mass production will get under way. With an estimated cost of “several hundred dollars,” they better plan on making a lot of them since not only are they a wonderful “solution” for several cities and ridesharing programs already showing interest, but in a world-economy that can’t afford to buy cars the way they used to, the GreenWheel should have a bright future.

[Source: MSNBC]

I came across this interesting news release on the American Council for an Energy-Efficient Economy (ACEEE) website this morning.  It makes some interesting projections of possible energy savings in Virginia.  However, in skimming through the report available at the ACEEE website (site requires registration to download the full report) I failed to see any estimates of the capital outlays needed to effect these recommendations and the ensuing cost/benefit analysis of these recommendations.  The report would be more credible if it would have done so.

American Council for an Energy-Efficient Economy
presents comprehensive findings at the
Commonwealth of Virginia Energy
& Sustainability Conference

FOR IMMEDIATE RELEASE

September 19, 2008

Richmond, Va.: By investing in energy-efficient technologies, the Commonwealth of Virginia can reduce its electricity needs by one-fifth; deliver cleaner, less-expensive power to Virginia consumers; create thousands of new jobs; and better position the state to more cost effectively meet its future energy requirements, according to a new report by the American Council for an Energy-Efficient Economy (ACEEE).

The report, entitled Energizing Virginia: Efficiency First, concludes that the Commonwealth can meet close to 20 percent of its electricity needs by 2025 through energy efficiency, a strategy that also would cut Virginians’ utilities bills by $15 billion by 2025 and create nearly 10,000 new jobs – the equivalent of bringing almost 100 new manufacturing facilities to the state.  And by reducing electricity use, Virginia can play its part in reducing global warming and contributing to a more sustainable environment.

The findings, which include 11 recommendations for Virginia’s policymakers, were presented today at the COVES (Commonwealth of Virginia Energy & Sustainability) conference to Virginia state energy officials and the public by Dr. R. Neal Elliott, associate director for research at ACEEE, a nonprofit, nonpartisan organization dedicated to advancing energy efficiency as a means of promoting economic prosperity, energy security and environmental protection.

Prior to issuing the report, which focused exclusively on the Commonwealth, ACEEE had ranked Virginia 38th out of 50 states in employing energy-efficiency programs and technologies.  Virginia is the latest in a series of states to receive ACEEE’s analysis.

“Our focus on Virginia was predicated on two factors,” Elliott said.  “First, the Commonwealth can realistically achieve significant savings – reducing electricity use by almost one-fifth by the time today’s newborns reach college – by making a commitment to energy efficiency.  And second, Virginia’s political climate is ripe for taking the action necessary to make real and lasting change.  Given Gov. Kaine’s leadership, the state’s reputation as exceedingly well-managed, and a bipartisan commitment from state legislators, we are optimistic that Virginia can become an exemplary state in the area of energy efficiency.”

Stephen Walz, Senior Advisor for Energy Policy to the Governor, stated that, “The Virginia Energy Plan, issued by Gov. Kaine last fall, called for Virginians to take all cost-effective energy conservation and efficiency actions as the first steps towards a more secure energy future.  This comprehensive analysis of how energy efficiency can help meet the Commonwealth’s electricity needs will help inform the Commonwealth’s analysis of our opportunities for the most effective energy efficiency actions.  I am pleased to accept this report and thank ACEEE and its sponsors for their hard work in developing their recommendations.”

Key Findings

On a sector-by-sector basis, the report concluded that by 2025, Virginia can achieve more than 20 percent reductions in electricity consumption in the following ways:

• In commercial buildings, replace incandescent lamps, enhance fluorescent lighting and employ lighting control measures as well as installing new HVAC systems.
• In residential housing, utilize more efficient heating and air conditioning systems, improve insulation and windows, and make improvements in residential lighting.
• In industrial facilities, employ more efficient electric motors and pumps, improving duct and pipe insulation.

The study also found that energy efficiency and demand response can reduce peak demand, which occurs during those days in the summer when electricity use is highest. Energy efficiency, together with demand response – i.e. shifting consumer demand for energy from peak periods to off-peak periods – can reduce peak demand by at least 26% by 2025.

The report confirms that energy efficiency has the potential to reduce consumer electricity bills by bringing down overall consumption.  And at one-third the cost of new conventional energy supply, energy efficiency has the added benefit of moderating future electricity price increases. According to the study, the recommended policies can cut customer electricity bills in Virginia by a net $15 billion by 2025.

Policy Recommendations

The report provides 11 specific recommendations where policymakers can begin creating a more favorable environment toward energy-efficiency programs.  ACEEE recommends, for example, that Virginia set a quantitative, long-term energy savings goal of at least 15 percent by 2022.  It also suggests creating a government/industrial collaborative called the “Virginia Manufacturing Initiative” (including university-based Centers of Excellence) to address the key barriers to energy efficiency.

The study also suggests that Virginia can lead by example by improving the efficiency of its own state and local government facilities; integrating efficiency into new buildings in Virginia by revising energy building codes that could reduce energy use by 30 percent; and undertaking an assistance program that helps low-income households adopt energy efficient practices, such as home weatherization programs.

Energizing Virginia: Efficiency First can be downloaded for free at www.aceee.org/pubs/e085.htm or purchased for $65 plus $5 postage and handling from ACEEE Publications, 529 14th Street, N.W., Suite 600, Washington, D.C. 20045, phone: 202-507-4000, fax: 202-429-2248, e-mail: aceee_publications@aceee.org.

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This article in Renewable Energy Weekly caught my attention this morning. The author, Charles Cresson Wood, offers up a scary proposition, that “At that point, it won’t matter who you are, or how important your organization’s mission is, nobody is going to produce the commodity your organization may be dependent upon.” I beg to differ with Mr. Wood, as it is my belief that the market described by Adam Smith over 300 years ago in An Inquiry into the Nature and Causes of the Wealth of Nations is still alive and healthy, and that as long as there is a demand for a product and there is a potential supply to meet that demand, the market will deliver that product; the catch is, at what price?  Oil may get very expensive, true, but I hardly think “…nobody is going to produce the commodity…” as Mr. Wood asserts.  What think you?

September 15, 2008
High Costs Could Prompt Premature End to Oil Production
by Charles Cresson Wood

Consider what’s now happening at the major mining companies as a harbinger of what we can expect to see with oil production companies. According to a recent article appearing in The Wall Street Journal (link below), a number of mining companies are curtailing certain of their operations, in some cases shutting them down completely. The explanation, which at first blush seems strange, especially given the run up in commodity prices over the last few years, has to do with operating and investment costs. The cost of energy to run mining trucks and other equipment has skyrocketed. In addition, certain materials needed to make mining buildings and related infrastructure, materials like steel, have also become considerably more expensive.

Mining nickel, lead, copper and other metals from the ground actually has many similarities to pumping oil out of the ground. While the processes are technologically different, in both cases we are talking about discovering and extracting a commodity that is in limited supply. In both cases, the supply of these commodities is in the process of being exhausted, and as a result, these commodities are increasingly more difficult to find, and increasingly more expensive to extract from the earth. For example, no new giant oil fields are being discovered these days. Producers must now go into very inhospitable environments, such as the bottom of the sea, in order to find significant new deposits of oil.

In the future, firms that are mining minerals, and firms that are producing oil, will both be hit with the double whammy of higher energy prices combined with higher commodity prices. Higher energy prices mean that the cost per ton of ore produced, or the cost per barrel of oil produced, will be higher than it was in the past. Higher commodity prices will discourage investment in new and more efficient infrastructure, just as it will discourage efforts to develop additional deposits.

As was the case for carrier pigeons, bison and many other animals, the extraction of these “resources” continues until it is no longer economical. Personally, I think it’s deplorable that organizations make these decisions primarily based on economics, but that’s the way the system is set up right now. So the production of minerals and petroleum from the ground will continue until it is no longer economical for the producers to engage in this activity. This point comes when the variable operating costs, and the fixed investment costs, both mentioned above, no longer look attractive relative to the revenues that can be obtained from further production activities.

Exactly when this point will come for oil or other commodities is hard to estimate. Many factors will affect this timing, including remaining supplies, prevailing demand levels, available technology, government subsidies and taxes, as well as the cost of capital. The important take-away point is that there will come a time when the producers stop producing, NOT because supplies have run out, and NOT because demand has dried up. At that point, it won’t matter who you are, or how important your organization’s mission is, nobody is going to produce the commodity your organization may be dependent upon….

…Charles Cresson Wood, MBA, MSE, is an alternative fuels management consultant with Post-Petroleum Transportation in Sausalito, California. His most recent book is Kicking The Gasoline & Petro-Diesel Habit: A Business Manager’s Blueprint For Action. You can learn more about the book, read his alternative fuels blog, and reach him at www.kickingthegasoline.com.

Source: http://www.renewableenergyworld.com/rea/news/reinsider/story?id=53557

I saw this item on the “Autobloggreen” blog this morning, which led me to this article and thought you may be interested.  I was vaguely acquainted with the Atkinson Cycle before, but this article explains the theory and practice behind it.  This makes the Atkinson Cycle engine better, if not ideal, for a hybrid vehicle, in that a full hybrid ICE can be kept in a tighter engine RPM operating range and make use of the higher efficiency of the Atkinson Cycle.  Comments?

Atkinson Meets Otto: Why the Prius is So Efficient

This imbalanced compression/expansion ratio results in a reduction of what are called pumping losses. It produces a difference between how hard the engine works and how much power it develops.

In the case of the Prius engine, the effective compression ratio is about 8:1, while the expansion ratio is about 13:1. As a result, it is 12% to 14% more efficient, in terms of power output per fuel consumed, than the non-Atkinson engine upon which it is based.

But there’s no free lunch. Use of the Atkinson cycle results in improved efficiency, but it also results in a significant narrowing of the rpm range in which the engine makes useable power.

There are two ways to solve this problem. One way is to couple the engine to a continuously variable transmission (CVT) so that the engine always will run in its optimal rev range. The other is to give the engine supplemental power such as an electric motor. We do both those things.

Even better, by using our Variable Valve Timing-intelligent (VVT-i) system to continuously adjust intake-valve timing between Atkinson-cycle valve timing and conventional valve timing, the Prius engine can maximize fuel efficiency while still producing maximum power.

The result is the Prius Hybrid, which provides sprightly acceleration, more than sufficient highway speed and the best fuel economy ratings of any automobile available in the U.S. today. Seems like the best of all possible worlds.

- Jon F. Thompson, Editor, Open Road