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"Less unsprung weight helps vehicles start, stop and turn faster by reducing wheel rotational inertia, significantly improving response time to driver input." Surely you must mean less rotational weight, not less unsprung weight, right? There are lots of ways to reduce unsprung weight that don't reduce rotational inertia, just as there are many ways increase unsprung weight without increasing rotational inertia. In this case we have a reduction in unsprung weight and a reduction in rotational weight which are both good things, but let us not confuse the two subjects.
"Less unsprung weight helps vehicles start, stop and turn faster by reducing wheel rotational inertia, significantly improving response time to driver input." Surely you must mean less rotational weight, not less unsprung weight, right? There are lots of ways to reduce unsprung weight that don't reduce rotational inertia, just as there are many ways increase unsprung weight without increasing rotational inertia. In this case we have a reduction in unsprung weight and a reduction in rotational weight which are both good things, but let us not confuse the two subjects.
No I was wrong... the 2 MW HR system is 700 kWh, per the link above. HR stands for "High Rate".
Davemart, the article does say it is 2MW HR, by which I believe they mean 2 mWh, which is 2,000 kWh. They can apparently make a single container up to 4 mWh: http://www.a123energy.com/084a3550-d058-44d0-bd0d-34125b79d4bd/download.htm
Great news! If it isn't already in the planning, they should add what I'd call a distraction endorsement. This would be a rating of a driver's ability to deal with distractions such as passengers, children as passengers, telephones (hands-free or otherwise), navigation systems, eating food, personal grooming, changing radio stations, all of which have different levels of difficulty while driving. Some people are true multi-taskers and could possibly do all those things simultaneously while driving without being a hazard to themselves or others. Most of us (like me) can't multi-task very well at all. Those that have such proven ability via such simulation, should be entitled to a top-rated endorsement while the rest of us might barely qualify to have adult passengers, let alone telephones while driving. This would be a way to put some science to the subject of distracted driving, instead of what is otherwise a very emotional and subjective subject, as demonstrated by the US government's dismay over how traffic fatalities keep decreasing as highway speeds increase and as driver's are increasingly distracted by vehicle gadgetry. I can hear the looming argument... but are simulators a good judge of critical skills? It seems to work for airline pilots pretty well.
Engineer-Poet, have you ever seen the size of a 445 kW liquid-cooled resistor, or even one 1/10th that size? Finding a place to put this resistor and making it less expensive than friction brakes is the trick. The motors can likely be scaled to handle the power, as they are already at 80+ kW each, but there needs to be a practical place to put that power, and as you said that's going to be at least some friction braking for the for foreseeable future. Some, but very few battery technologies, such as Altairnano, can handle pulse charging at the same rate as pulse discharging, so there is hope to actually capture that energy instead of wasting it. Indeed Arnold, steerable wheels are more sensitive to unsprung mass, but these motors are powerful enough to be used on rear wheels-only for through-the-road hybrids and smaller EVs.
Many of the commentators above would have benefited from going to Protean's web site (http://www.proteanelectric.com/)to read more about the technology before posting. 1) The Protean Drive system uses a conventional wheel and tire that can use conventional mounting and balancing equipment. Removing the motor to steal it will be considerably more difficult than removing the wheel, especially if the intent is to not damage it or its cables while removing it. 2) Indeed friction brakes (albeit smaller) are still likely to be needed with the Protean Drive system and it can support several mechanical braking configurations, but the motor isn't the cause for this need. It is the battery that is main reason the regenerative braking energy can't always be absorbed, due to too high a state of charge, maximum charge rate limitations, or too high or low of operating temperature. Solving this problem will pave the way to all-electric brakes someday. 3) The concept of multiple internal inverters provides modularity and redundancy, benefits from a wider selection of power electronics components, and leverages the proven economies-of-scale associated with high volume electronics manufacturing. 4) Mr. Purcell is attributed to bringing the EV1 into production, along with many other technical innovations that likely flew in the face of GM's upper management. He was never implicated in having pulled the plug on the EV1 in any movies, books, or Internet conspiracies. He should be a great asset to Protean as this technology moves toward production. 5) Unsprung mass concerns are overblown, especially on mid-size and larger vehicles, as only time and test driving will prove. Damper tuning has tremendous positive effects, especially with modern day active damping technology and upcoming active suspension systems. Consider the live rear axle in a modern pickup or SUV and how much this technology could actually reduce unsprung mass. 6) Other in-wheel motor systems, such as Michelin's, use gear drives to increase torque at the wheels which causes audible gear noise and efficiency losses. Integrating the power electronics as Protean's system does offers great packaging and EMC advantages by not needing to find another place in the vehicle for that electronics. 7) There are several working concept vehicle models, as Protean has been publicly demonstrating, and as shown on their web site. The existing motor, their PD18, is just one of many models coming in their future road map, and each one is capable of more than 80 kW (>100 HP), battery permitting.
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Oct 10, 2010