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Below you will find a small sample of the questions that are repeatedly asked or comments that are continually made in questioning the viability of the e-Traction® System (answers are presented in the following order and are found by scrolling to the relevant section):
"Unsprung Mass" theory does not apply At the time of this writing, we are putting the finishing touches on our third bus, the Whisper. Our first bus, “The Whisper”, displayed excellent road holding characteristics and a much higher passenger comfort level than previously anticipated. The e-Traction® Bus, our second bus, has logged many miles and displays fantastic handling. This has confounded those who were convinced we would encounter problems from the "Unsprung Mass" of our traction system. We are unlikely to encounter this problem in our current applications because: The “Unsprung Mass” of a typical conventional rear axle of a bus hovers around 600 kg. Our universal rear axle with two TheWheel™ SM500/2FE units and its brake system weighs roughly 1,400 kg. This “mass” will be agitated by the conditions of the road and magnified by speed. Neither of those two issues really apply for a city bus that operates at reduced speeds and on normally smooth surfaces. Though the curb weight of our hybrid (batteries and/or a generator provide the electric power needed) electric direct drive e-Traction® bus is roughly identical to its conventional sibling; the weight our traction system is, however, located below the suspension. We are, therefore, able to operate the air-suspension system at a lower level of stiffness thus giving the passengers a more comfortable ride. We frequently operate both the e-Traction® Bus an d the Whisper on not particularly smooth roads at speeds up to 80 KMH without manifestation of any of the alleged "Unsprung Mass" problems. VDL Berkhof, a renowned coachbuilder in the Netherlands and the supplier of the body for the Whisper, based on its recent experiences with our technology, has acknowledged that this theory does not appear to hold much water in relation to our traction system in its current applications. Time between overhauls hardly an issue The entire inner workings of our traction systems are solid state. It will work just as well twenty years from now as it does today (assuming proper use). The e-Traction® System has only one moving part, the rotor, which is held in place by high quality bearings. These very expensive bearings were purposely and very conservatively chosen to avoid them ever becoming a potential source of failure. They are rated to easily handle the normal and peak loads for a minimum of 1.000.000 KM in normal operation. Friction is the greatest source of waste Because the e-Traction® System has only one moving part, the rotor, it has very little friction (see: Mechanical Efficiency). It takes just 80 kg of pulling power to move a 9 metric ton bus equipped with our system. The same bus with a conventional traction system would require 140 kg in pulling power. This added friction from all the bearings, the differential and the gearbox must be continually overcome by the, less than efficient, conventional diesel traction motor. Just replacing this traction motor with an electric one, as is done in most "hybrid" configurations, can therefore never yield the same efficiency demonstrated by the e-Traction® System. Not only fuel consumption, but also CO2 emissions drops dramatically One e-Traction® powered bus reduces CO2 emissions by (30,000 liters * 2.7 kg/l) 79.4 metric tons per year (see: Air Pollution). Public transit bus replacement requirement in the Netherlands is 500+ buses per year. Hence, if all of those buses were to be powered with the e-Traction® System a reduction of (500 x 79.4 =) 39,700 metric tons of C02 could be achieved each subsequent year until all busses have been replaced. The gradually converted fleet of public transit buses would reduce CO2 emissions during the next 10 years by: 2,183,500 metric tons CO2. Most private cars are relatively fuel efficient An article in the U.S. magazine Autoweek highlights this point when it compared its long term usage test of the Toyota Prius with that of the Honda Civic LX. Whereas the Prius had an average fuel mileage of 43 MPG the Civic still managed a respectable 33 MPG. Factoring in the prevailing fuel price at the time and the non subsidized price of both vehicles, they determined that it would take 333,333 miles for the owner to break even in the incremental cost of the Prius (see: Energy Efficiency). Once the production cost of the e-Traction® System is reduced through mass production, it will become a serious alternative for newly designed vehicles. A retrofit of existing vehicles is quite possible, because the cost of conversion will most likely only "pay out" on high usage and/or low fuel mileage vehicles such as SUV's and delivery vans. Fuel cells as a source of energy are much more viable using the e-Traction® System. The current fuel cells are powering geared electric traction systems using many friction producing power transfers. The fuel cell bus used in Amsterdam uses 1 kg of hydrogen for every 4.8 km covered. Were this bus to have been equipped with the e-Traction® System it could cover 19.5 km with the very same kilo of hydrogen (see: Fuel Cell Alternative). This improved efficiency would eliminate to a large extend the storage problems currently hampering its development. The "Hydrogen Bus" of Amsterdam can operate only half a day before it needs to go back to its base for a refill. Were this bus to have been equipped with the e-Traction® System it would be able to use a much smaller fuel cell and only half the storage to operate a full day's duty cycle. Nm, not kW, indicates true performance Torque, measured in Newton Meters (Nm), is a meaningful measurement to compare electric motors while kW is not. The system used on the e-Traction® Bus and Whisper, TheWheel™ SM500/2FE, produces 8 Nm/amp, which is extremely high for the size and weight of such an all-inclusive unit. Our SM 700/3FE, by which the diameter of the rotor was raised from 500 mm to 700 mm, produces an astounding 21 Nm/Amp. Acceleration could rival with the best Assuming a sufficiently large energy supply a system such as our will outperform conventional traction system in each respective weight class. For instance, provided we can supply our TheWheel™ SM700/3AL system with a steady supply of 400 VDC and 1,000 Amperes, we should be able to produce a continuous acceleration of 1G to the maximum speed. When designing a vehicle for efficiency, however, acceleration becomes at best secondary concern. The weight penalty of carrying 1,000 Amp capability, in oversized battery storage and/or generator, would adversely effect the energy efficiency of the vehicle. Climbing obstacles or hills not a problem TheWheel™ SM500/2FE, which is being used on our recent buses, can make a continuous climb and accelerate from a full stop on a 15% gradient. It can also briefly overcome a 20% gradient obstacle such as a curb. e-Traction® System weighs less One can not compare the weight of the all-inclusive e-Traction® System to that of a simple electric motor. Our system will merely need a steady supply of direct current from any source and input from the operator via a CANopen system. All systems to make the alternating current motor work properly are built into this very wheel. A conventional electric traction configuration, however, would still need some type of mechanical gearing and/or power transfer to be able to propel individual wheels. Furthermore, it most likely would need many supplemental electrical components (inverters, cables etc.) to add up to the same functionality of our complete traction system (including ABS, traction control, regenerative braking to name but a few). The combined weight of a conventional system is likely higher and much less compact and versatile than the e-Traction® System. Tire wear is significantly lower The endurance of the tires on our e-Traction® Bus has been shown to be much better than that of a conventional bus. Not only do they not hob as predicted by the "Unsprung Mass" theorists; based on the steering deflection of the operator each powered wheel receives the exact amount of torque needed to manage the turn. That novel capability reduces tire wear on the traction wheels as well as the front (steering) wheels, because there is no need to fight the differential in the turns. Lower rear bus floor possible The specially designed "universal e-Traction® rear axle" makes it possible to lower the floor between the rear wheels to 50 cm above the road surface with a 80 cm aisle in European configuration. In North American configuration the aisle width increases by another 10 cm to 90 cm, while the ground clearance in both configurations is almost 15 cm. This system works where others failed The electric wheel hub motor concept is more than 100 years old (see: history) and most of them have proven to be less than commercially successful. We are not sufficiently familiar with all the reasons behind the lack of apparent success of the other initiatives. It is certain that we too would likely have failed if it were not for the latest electronic developments and battery technology. The official certification of the fuel consumption e-Traction® Bus is a fact that has become impossible to refute. The integrated system is worth every penny Our all-inclusive systems certainly may at first glance appear to be expensive, but not much more than a conventional diesel motor, gearbox, rear axle with differential combined. Furthermore, they are highly durable and easily recyclable from one vehicle to the next. To make it work one just needs to secure a steady supply of DC current, the extend of which determines the top speed. We are using with impressive results initially expensive, but ultimately cheaper Lithium-Ion batteries. In addition to batteries one will need some computer hardware to manage the individual systems from the driver position (accelerator, brake pedal, and a CPU). The systems have a five year warranty (if used in accordance with the specifications) and are designed for 1 million kilometers between preventive maintenance replacements of the bearings. Whatever the initial purchase price, it pales in comparison to the lower cost of operation in public transit while the environmental benefits are priceless (see: operational efficiency). Lithium-Ion batteries an efficient choice We have experimented extensively with different types of batteries and have become convinced that Lithium-Ion currently offers the best performance and value per Ah delivered. Their size and weight, the number of cycles we can obtain during their lifespan, and the amount of energy that is available in each of these batteries make them an efficient and ideal choice for our applications. Today's purchase will influence the environment for many years to come It should by now have become abundantly clear that purchasing a conventionally powered vehicle today, ignoring serious consideration of novel capabilities of systems such as ours, will put an unnecessary burden on the environment that will ultimate wind up being much more costly decision than might be initially apparent during its economic lifespan of usually more than 10 years. e-Traction® System takes electric energy from different sources. Does that make it a "Hybrid"? The meaning of the word “hybrid” is sufficiently confusing due to a lack of a standard. An e-Traction® powered bus is not a conventional “hybrid” because, unlike all the currently available parallel hybrid vehicle offerings, it will always be propelled by its electric motors. The manner in which electricity, the sole energy used by the traction system, is provided is truly flexible and usually comes from at least two or more sources. The primary energy source will likely be Lithium-Ion batteries that can be charged, aside from regeneration, in many different ways. Whether one uses the power grid, a pantograph access to power (trolley or tram) and/or a fuel cell, or a fossil fuel (bio-diesel, LPG, CNG, or diesel) generator is truly the operator’s choice. The e-Traction® System may simply not be lumped together with all that claims to be “hybrid” and thus supposedly fuel-efficient. Its fuel savings and reduced CO2 emissions put it in a league of its own. All-electric vehicles - not necessarily better for the environment? A purely battery powered and a (diesel) generator version of the Whisper produce almost the same amount of CO2 emission, be it at different locations. Assuming the energy used to recharge the batteries comes from a fossil fuel burning power plant, the pollution burden can thus be moved but not removed (see: Fuel Consumption Calculator) The noise level of either version of an e-Traction® powered bus will be relatively similar at 60 DB or below. The super-single tires are currently our largest source of noise. One e-Traction® powered bus equals savings of more than 112 Toyota Priuses In a typical Dutch transit setting, our system would yield annual savings of 30,000 liters (7,925 US gallons) of diesel per bus. The much touted Toyota Prius saves on average 70.5 US gallons when used on average for 10,000 miles per year. The owner is invariably enticed to purchase it with some kind of government incentive, such as a tax rebate, to encourage its purchase. One city bus equipped with our system produces the same CO2 reduction of more than 112.4 such Priuses. This is not to say that the Prius should not be preferred over conventional cars, because it is definitely better for the environment; the government would, however, be much wiser in tackling its own fuel guzzling mass transit system instead of subsidizing private vehicles that are used relatively little. The investment yield, in terms of energy saved, of the incremental cost of an e-Traction® powered bus is is 36.6 times higher than the yield of the energy produced by a Toyota Prius (see: energy efficiency). 15 e-Traction® powered buses annually save the same energy one 2 mW windmill can generate. An e-Traction® powered bus annually saves 1,161,000 mega Joules (mJ), whereas a windmill, costing more than €3 million each, on average produces 17,280,000 mJ. The incremental cost of an e-Traction® powered bus will eventually be minimal but is currently estimated in series production to hover around 10% or €20,000. Twenty eight buses, producing the same energy savings generate by a windmill, would thus represent an incremental outlay of € 297,674 or little more than 10% of the investment otherwise needed. In addition, the e-Traction® powered buses, compared to their conventional alternative, are a substantial improvement for the environment in which they operate. The windmill will use land and is subject to extensive environmental impact scrutiny. The investment yield, in terms of energy saved, of the incremental cost of an e-Traction® powered bus is is 10.1 times higher than the yield of the energy produced by a windmill (see: energy efficiency). 6,719 solar panels are needed to generate the energy saved by one e-Traction® powered bus. The incremental cost of one e-Traction® powered bus, which saves 1,161,000 mega Joules annually, is €20,000. To produce that amount of energy would require 6,719 solar panels of 1 m2 costing € 500 each. To yield the same amount of energy saved by just one e-Traction® powered bus with solar panels, in the Netherlands, would therefore require 6,719 m2 of land and cost € 3,359,375. The investment yield, in terms of energy saved, of the incremental cost of an e-Traction® powered bus is is 168 times higher than the yield of the energy produced by solar panels. In addition, the e-Traction® powered buses, compared to their conventional alternative, are a substantial improvement for the environment in which they operate (see: energy efficiency). |
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