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Heavy-duty trucks spend more time on the road than passenger vehicles, so improving their efficiency can have a major effect on emissions--and their owners' bottom lines.
That's why Walmart is getting into the truck-design business with the WAVE--Walmart Advanced Vehicle Experience--concept.
The drivetrain concept is unique, yes... a hydrid EV, with a micro-turbine charging batteries that power the electric motor(s). I foresee a long development cycle to bring that concept to market, if they do at all, but faced by federal mandates to improve their fuel efficiency, they have to do something.
I think the part of the concept most likely to be adopted first might be the use of carbon fiber elements, which lighten weight over steel parts yet retain strength. Although more expensive initially, if used well they can more than pay their way in reduced fuel costs over the life of the vehicle.
This is actually a take off from the mining industry where diesel engines generate the electricity of electric motors so the concept is proven, the big refinement is the use of the turbine. Most of the development work has been done already since they are leveraging existing technology, just updating it.
There are many other important benefits that go along with this idea, power being one of them. While distributed inventory can go a long way to reducing the need to transport goods, once most of the inventory started being produced overseas, the distances needed to transport that inventory became something of an issue that couldn't be mitigated, the materials have to reach a port and those ports are fixed points.
The high torque available will increase the efficiency of the "tractor" for many routes, that will speed delivery times and time on the road with floating inventory is money tied up. The shorter the time inventory spends in transportation, the more money the business can make, there is a direct correlation when you include the reduction in storage inventory required. Apple knew about that and used it at great advantage within the last several years.
Doubtful the carbon fiber uses will survive any production since this design was a proof of concept, not a prototype on the way to production. While using other materials will increase the weight, when the overall weight is getting into the 80,000 range, the difference between carbon fiber and aluminum is inconsequential when all the other factors are also considered.
This vehicle demonstrates a competitive drive train that has many implications in the transportation industry, even down to regional and local delivery vehicle designs.
The railroad has been using electric engines for years, fed by a diesel generator. WalMart has always been looking at ways to cut costs and this is just one of them. They do almost all of their own trucking, a trend that started a few years back when they decided they could see a savings by doing so.
If this the wave of the future? I think it is. You see many fuel savings efforts everyday with trailers that have wind flaps under and behind them. That article states they got 13+ miles per gallon, over twice what the average truck gets. That average less than 20 years ago was about 4.
I see a turbine is used, presumably to turn a generator which drives the electric motor. We may assume the fuel is diesel, but it's not specified. The video shows a centric driver seat, but pedals on the floor are on the right side of largish divider, which means the driver can't sit square in the center. We have no information on MPG, size of the generator, capacity of the battery system. Lower weight sounds good in a trailer, until a 50 mph gust hits the side of the empty trailer while it's going over a bridge and the truck jackknifes.
While it looks pretty, there seem to be a lot of unanswered questions. I see Peterbilt in the video, and when visiting the Peterbilt website, it appears our federal department of transportation is giving hundreds of millions of dollars to company's trying to develop improved MPG large trucks to meet new mandated federal standards. Was the WalMart truck made by Peterbilt? Is the truck paid for by tax dollars or by WalMart dollars?
I see a turbine is used, presumably to turn a generator which drives the electric motor.
There's one more system in the flow, which is typical for "hybrids"... The turbine drives a generator which charges batteries, and power from the batteries drives the electric motors(s).
There's one more system in the flow, which is typical for "hybrids"... The turbine drives a generator which charges batteries, and power from the batteries drives the electric motors(s).
It may make sense to use energy stored in a battery if a generator isn't running. However if a generator IS running, it isn't possible to simultaneously charge and discharge any battery I've encountered through the terminals. The terminals would just conduct current to the load (electric engine).
It may make sense to use energy stored in a battery if a generator isn't running. However if a generator IS running, it isn't possible to simultaneously charge and discharge any battery I've encountered through the terminals. The terminals would just conduct current to the load (electric engine).
It isn't done through the terminals, but through a computerized power management system. Hybrid vehicles use them, solar PV systems use them. At times the generator might be generating more power than the motor is drawing so the battery can be charging, while at other times the motor might be drawing more power than the generator is putting out, so the battery can be discharging. In addition the regenerative braking systems generate additional electricity, but intermittently. The power management system handles the complicated balancing act required to have it all work out OK.
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Quote:
Originally Posted by Zot
pedals on the floor are on the right side of largish divider
And there are two pedals on the right side,
Probably just accelerator and brake ?
So no left foot action required
Last edited by irman; 03-07-2014 at 09:51 PM..
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