The American fascination with mobility, aka the automobile, is going through a lot of change presently. The introduction of the Segway began a new generation of personal mobility devices. And the demand for environmentally friendly means of transportation have added unique constraints to all of the vehicle offerings coming to market from both large and small manufacturers.
The direct energy cost per mile or equivalent mpg is one measurement of performance for human mobility. A fully loaded cost per transportation mile, including vehicle cost, insurance, maintenance, etc., is more consistent with what we really experience. So there are competing values that each person must consider in the mix of personal mobility.
2 wheeled transportation used to mean bicycles and motorcycles. But the boundaries are getting fuzzy. The Seqway puts the two wheels side by side with independent drive motors with a drive train similar to an electric powered wheelchair. The wheels are independent and capable of operating as an electronic differential permitting these systems to turn in place, a turning radius of zero! Pretty neat from a maneuverability standpoint.
But the new EN-V from General Motors takes the Segway concept to a 2 passenger vehicle that’s smaller than the Smart Car and designed for short range city mobility. It’s very compact at 1/6th the footprint of a small car, so parking is not a problem. And since it’s enclosed, it works in the rain. The battery powered drive train will reach 24mph maximum speed. Driving range and equivalent MPG’s have not been announced.
All of the mobility issues are tied up in one formula, namely F=ma. Force = mass x acceleration. So as the mass of the vehicle and its design payload, passenger capacity, is reduced, like in a Segway, a motorcycle or the new EN-V, the force needed to move that mass is decreased proportionately. A 1 or 2 passenger solutions is much easier to deal with than a mini-van that has to have a 400 mile drive range.
In a very extreme response to the mass part of the equation, Honda has demonstrated it’s U3-X electric unicycle, borrowing the balancing concepts of the Segway, but converting the drivetrain to a single wheel system with perpendicular rotating elements where the tread would be so that the unit can move a person from side to side. (check the video demos on YouTube) At 22 pounds it is an astounding feat that it can move a person comfortably at 4 mph for 1-2 hours.
The General Motors EV-1 had over 2200 pounds of lead acid batteries in it. Which made it impractical. With the improvements of lithium batteries, a 400 pound payload of batteries, which is much more acceptable, makes electric vehicles practical on a technical level. But due to lithium batteries cost, the Tesla roadster battery pack being well in excess of $10,000, the hybrid solution becomes more cost effective.
By reducing the drive range and acceleration, energy storage requirements are greatly simplified. The designer can focus on the exact type of mobility sought in a given new product. This change in thinking is giving rise to a whole new group of design concepts including autonomous drive options as envisioned in “Minority Report” and the recent DARPA autonomous vehicle challenges.
In crowded urban areas with a highly networked communications infrastructure, new options like the EN-V become much more interesting, more cost effective at many levels, and potentially more safe than today’s smog filled city centers. And as the supporting technology in battery storage and electric motor technology continue to progress, new solutions and options will continue to be pioneered.
I like new options.