The car of the future

[Remundo]

to dry a Lithium in self-discharge, it takes months and months ...

On the other hand, it is true that a Lithium dried at 0V, and well it will do it only once ... In other words the battery will be dead, while a Nicad starts again as in 40.

And the "special storage" mode of the Tesla must be a system that minimizes the electrical servitudes of the car.

[I Citro]

As always, buying an innovative vehicle means taking risks.
That said, there are economically relevant choices in hybrid and electric.
It is clear that the market is not yet ripe.
This is why traveling to events like this is so essential.
Your servant will be waiting for you at the Mobil-Eco stand. :

[Macro]

since this subject has come up: a real question for my ultralight car of the future: which wheel size to choose?

the most common tire size currently is 155 / 70R13

to have a smaller size, these are trailer tires that are not even radial tires: that therefore wear out faster and lose more energy

I’m thinking of a pancake wheel, like 115 / 70R15 with the same diameter as the 155 / 70R13

The flat tires are tires intended for temporary use of one they have a very low speed index (80km / h) maximum and melt like snow in the sun ... Avoid ... We still find very easily at very low prices affordable from 135 / 15.Or 135 145 / 13..Du 125 or 115/15 must be able to be found with a T index which is enough ...

For the tesla. The European price is almost multiplied by 3 compared to the US price ... It's that they don't want to bother to sell it ... Importing one yourself is completely impossible (market locked by the importer of record) ...

[chatelot16]

flat tires have a limited speed when made to take on the load of the larger tire ... but I think that if they are used at low load, they will have correct performance

I see that the diagonal tires always wear out faster than the radial ... and some flat tires are diagonal: I have seen 115D14 ... it may be those that wear out at full speed

the wear of the flat tire when you put only one on the car is not significant, firstly it is heavily loaded, secondly it is stiffer than the other tires, so when cornering alone takes a larger share of lateral effort: we can understand that he suffers

the advantage of the 115 / 70R15 is that it can replace the 155 / 70R13 running on small trailers: it would be an opportunity to try them on a trailer that does a lot of km

the 155 / 70R13 are too big for small trailers, but the manufacturers put this dimension everywhere because it is the cheapest available ... putting smaller tires better suited to the load would be an interesting experience

[Michel Kieffer]

Hello everybody

Here is a good opportunity to delve back into our automotive subject: we (HKW-aero) are co-organizing a conference on the transport of the future with the UTBM (near Belfort). Lovers of modeling are of course welcome. The subjects will concern the automobile, light aircraft, transport aircraft, trains and some original subjects such as suborbital flight for example (subject without interest given its extravagant energy cost, but very formative in terms of modeling and design). The theme "car of the future" will of course address the most interesting topics from our extensive debates. But above all I will not fail to stress the importance of forums (such econology ) to advance knowledge.

This first general conference introduces other conferences, but which will be specialized by theme: automotive, aeronautics, railways, etc.

Michel

Program available on the conference brochure, see page http://www.hkw-aero.fr/generalites.html

[I Citro]

chatelot16, the gums of temporary tires are formulated for very short use and will not last thousands of km, even if the wheels are less loaded.

Michel Kieffer, what a pleasure to read you, I took the opportunity to browse some of your old documents (I am preparing a conference and you are a good source of inspiration). I note that a lot has changed in recent years and some of your assumptions have lost their relevance, in particular your perception of the electric car and the role it can (and should) play in the mix of future transport.

Furthermore, I did not find in your presentations any reference to the transmission efficiency of vehicles and their link with the overall performance of the vehicle.
You will agree that optimum consumption will be obtained by associating the engine speed with the optimal transmission ratio. It is for this reason that cars which had 3-speed gearboxes in the 50s are now delivered with 6-speed gearboxes and that we are announcing the upcoming commercialization of 10-speed gearboxes ...

I recently got a close look at PSA's "Hybrid Air" prototype. The manufacturer announces an "approved consumption" of 3 liters per 100km for a C3 and makes a diversion on the real technological content of the vehicle which does not use air (it compresses nitrogen in an oleopneumatic circuit).
The main gain of the vehicle is at the level of the transmission WITHOUT GEARBOX but using a continuously variable transmission (CVT) very inspired by the one we know about Toyota Hybrids.
.
From my point of view, the cars of the future will have to be either:
- 100% electric (100.000 km of personal experience convinced me, I continue ...)
- Rechargeable hybrids according to the architecture of the Chevrolet VOLT or the Opel Ampera as well as the architecture of the Toyota PHEV
- Hybrids according to the Toyota HSD architecture, the continuously variable transmission of which is to date the only one whose performance is as high as its reliability is proven.
The latter is, moreover, the only "reasonable" hybrid that is manufactured in France with the Yaris HSD model.

In addition, you often mentioned the share of pollution from the electric car linked to the production of electricity.
The electric car is a tremendous asset for the development of renewable energies such as wind and photovoltaic connected to the grid. To do this, electric cars will have to be integrated into the SMART GRID, of which they will regulate peaks in renewable production and absorb peaks in consumption.
The most sold electric car in the world, the Nissan Leaf (more than 60.000 sales since its commercialization) is even designed to power the home of its owners in the event of a power outage. This excellent car, the new (much improved) version of which arrives on the market, is produced in Japan, the USA and England.

[Michel Kieffer]

Citro,

It is a real pleasure to come back to this forum which formatted me a lot (very positively). In recent years I, or rather our team, we have been "dispersed" in aerotechnics, a very interesting subject as you can imagine. Of course, the electric for cars previously optimized has a major interest. But thermal is not to be outdone, in particular by the recovery of kinetic energy, and this, provided that the mass in addition does not come to degrade the benefit of the recovery of Ec ... This subject will be discussed on June 6 by ourselves and by PSA and the Hybrid Air solution. The theoretical potential on mixed cycle is around 20 to 30%! As for mass, it is no coincidence that PSA equips this 208 not too heavy. Here is a very good start.

Michel

PS: See also Remundo's study on the recovery of kinetic energy.

[I Citro]

Indeed, this forum and the subjects covered also really mattered to me.

What time wasted by PSA when we see the 10 years ahead and 5 million cars sold by Toyota which now sells more than 2 Million per year and is made of profits ...
All the more so as PSA will not market the "Hybrid Air" for 3 years ...
For the weight, the car is not the heaviest but it also does not seek to reverse the spiral, just to contain it ...

[sen-no-sen]

Lovers of modeling are of course welcome. The subjects will concern the automobile, light aircraft, transport aircraft, trains
Michel

Well, I would like your point of view on the TGV, the TER and the endangered intercities (ex-coral) which seemed to me to be the best trains, econologically speaking?

[Michel Kieffer]

Sen no sen,

Parasitic drag increases with the cube of speed. That is to say that if the speed goes from 160 to 320 km / h, the power to mobilize = 2 to the cube 3 is 8 x more power… But as the beast goes 2 x faster, the consumption of energy increases not with the cube but with the square of the speed. That is to say 2² = 4 x more consumption, which remains enormous.

But the parasitic drag, that which is linked to the aerodynamic characteristics, absorbs only part of the total drag. The latter also includes running drag, considerable for cars (around 30%), low for trains (roughly 5 to 10%). This low train drag is explained by the steel-to-steel contact, therefore without large deformations of the link. But the corrolaire being a mediocre “handling” therefore requiring rails and long stopping distances.

In this sense, whatever the name of the train (TER, coral…), the important thing is to keep a “reasonable” speed. FYI, the TER runs at around 200 km / h in the Alsace plain, which is more than enough for inter-city links.

Michel