Economic analyzes on the passage from 90 km / h to 80 km / h in France ...

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Adrien (ex-nico239)
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Re: Economic analyzes on the passage from 90 km / h to 80 km / h in France ...




by Adrien (ex-nico239) » 23/05/18, 23:39

I like to reason with the absurd.

And why the speed would not be limited to 50 for example on all roads?

Basically this poses a problem identical to that of rising fuel prices

From what fuel price does the company collapse?
From what maximum speed on roads (outside agglomeration) society collapses?

I mean by crumbling, getting sore or something like that.

3 €, 4, 5, 6 € per liter for fuel?
80, 70, 60, 50 on the roads?

And instead of talking about the followers of the speed if one spoke about the followers of the slowness?
What maximum speed would they willingly accept for themselves?
80 is it already too much? 70, 60?
And are they already driving at this speed?
Finally nothing prevents them?
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Re: Limitation to 70 km / h on the device




by Adrien (ex-nico239) » 23/05/18, 23:54

Christophe wrote:Theoretically the power needed to overcome the drag would be increased by the ratio of velocities to the cube, ie 1,18 ^ 3 = + 64% ... hey! But no modern car consumes + 64% from 110 to 130 km / h, so there is good compensation by increasing engine efficiency. In the end, the increase is from 5 to 10% at most ... see not at all, even negative ... (uh a negative increase, it's a drop huh ...)



I am absolutely not a specialist in engines and their performance.

The question I ask is stupid, it's more like the couple and the minutes.

If we go down the speed, at some point we have to downshift because the car can not ride 70 or 50 5ème.

So the number of turns increases

Question: consumption too?
Or not?

In short I am a bit messy but I hope you understand what I want to express.

Reasoning the absurd city 30 I am in second.
If I make 100 terminals in seconds at 30 do I pollute more and consume more (or not) than if I drive in 5 or 6eme to 90?
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Re: Limitation to 70 km / h on the device




by Christophe » 24/05/18, 00:07

sen-no-sen wrote:Yes, I understood what you meant, but it seems to me that you overestimate the current technologies.

Image

This chart confirms it.


Ok I overestimate maybe a little the average power of the park! Okay ... okay!

What is the source and methodology?

It is not very different from this one: new-transport / analysis-economic-on-90-passing-km-ha-80-km-h-en-France-t15672.html # p339284 so I'm afraid it's the same methodology ...

So I would like to know for what average engine power it was established ... and what SCx and other parameters of the power equation I posted above ...

sen-no-sen wrote:
Auto Plus - which has an independent lab (see video) - released the 19 January 2018 consumer testing. Our guinea pig vehicle was not a Peugeot 308, but a Renault Kadjar dCi 130.


Verdict: the conso (steady speed) goes from 5,4 l / 100 km to 90 km / h to 4,9 to 80, 10% less, and so many CO2.

https://news.autoplus.fr/80-kmh-Vitesse-Consommation-Labo-Auto-Plus-Reportage-France-2-1524374.html


Ok..I can not find the video of the test ... a test drive that does not last hundreds of km is not worth much if we seek accuracy ... cons I noted that is very relevant and we have not yet mentioned: staging of gearboxes that may not be suitable for the new speed limits!

https://news.autoplus.fr/80-kmh-Vitesse ... 24374.html

Joebartaz wrote:10/04/2018 - 09:57
Here I just read this article and I want to add this: my laguna 1.9 dci 6 90 km / h nickel I have recovery in case of pb and I consume only 4L6 / 100 km but 80 km / h I do not think it's too dangerous so I stay in 5 and I use 5L4 / 100 km. Where is the economy and security in it?


sen-no-sen wrote:The reasoning is all the more true with electric vehicles:
Image


No, the consumption of a thermal car goes up at low speed so it is not the same reasoning as the conclusion of Auto Plus ... I said above: this reasoning that corrects the consumption by the efficiency n is not valid with electric and hybrid ...

As the efficiency of an electric motor is almost constant, its consumption will therefore be directly related to the necessary forward power, so not far from the cube of the speed from 100-110 km / h (speed where the aeronautical drag becomes largely predominant over the other forces) ... that's what this curve shows us.

On the other hand I am surprised of the point of inflection to 30 km / h of the Tesla and the Volt which should have the same behavior as all the others ... A reason for this?

Again, what is the source?
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Re: Limitation to 70 km / h on the device




by Christophe » 24/05/18, 00:13

nico239 wrote:If we go down the speed, at some point we have to downshift because the car can not ride 70 or 50 5ème.

(...)

In short I am a bit messy but I hope you understand what I want to express.


This is completely understandable and relevant and I just anticipated the answer by quoting the comment from "JoeBarTaz": lstaging of existing boxes may not be optimum at all with new speed limits ...

nico239 wrote:Reasoning the absurd city 30 I am in second.
If I make 100 terminals in seconds at 30 do I pollute more and consume more (or not) than if I drive in 5 or 6eme to 90?


So there it is no longer really a problem of gearbox staging but of thermodynamics and the curves above (although questionable because I do not have all the parameters) clearly show that we consume as much at 40 km / h at 110 km / h (hey yes ...) and that you will consume more at 30 km / h than at 90 km / h ... to make 100 km ... And we are not talking about the "loss of time "(it's also energy !! Huh human energy ... it costs too!)
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Re: Limitation to 70 km / h on the device




by Adrien (ex-nico239) » 24/05/18, 00:17

I admit that I did not read the whole subject ....

But on the pollution level what gives to lower the speed?

Does that lower the pollution from cars?

Neither should we reduce the number of deaths or injuries by 10%, but increase the number of cancers by the same amount ... oops
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Re: Limitation to 70 km / h on the device




by Christophe » 24/05/18, 00:28

Any engine has an "optimal" speed in terms of consumption, pollution and driving pleasure (torque reserve = safety ...) ... this optimum point is always a compromise between consumption, pollution and driving pleasure ... (and also wear ... in short engine manufacturer it's a job eh!)

Generally the manufacturers adapt on the legal speeds stabilized (examples: 50 km / h in 3ieme, 90 km / h in 5ieme and 120 km / h in 6ieme ... with the ladle) ... And it is there where the politicians are wrong to want to change the limits because the car fleet is not adapted ... AMHA! But it will be a good fit for the builders who will boost their sales in this way ... This is not the first legislative gift we give them and so much the worse for the planet!

For the anecdote, in the years 70-80, some manufacturers even made "vibrate" the car / the engine towards the 130-140 km / h (point of resonance) to dissuade the drivers to go faster, those who dared going faster could see that the vibrations stopped ... It was a bit the ancestor of cruise control! : Cheesy: But the technique was quickly stopped ... obviously : Cheesy:
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Re: Limitation to 70 km / h on the device




by Adrien (ex-nico239) » 24/05/18, 00:30

Ok thank you for this info :D
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Re: Economic analyzes on the passage from 90 km / h to 80 km / h in France ...




by Christophe » 24/05/18, 01:12

Forhorse wrote:The consumption curves have hardly changed because (...) but net power at maximum load is almost the same.


What time frame are you talking about? Because if it is since Euro 1 there has been a good -20% notably thanks to the common rail, reduction which is minimized by your point 2 it is true! All "ancillary" consumption has reduced the contribution of the engine improvement ...

It does not prevent the decline in consumption is still real, as the increase in comfort and safety ...

Forhorse wrote:- The technologies of depollution (EGR, catalysts, etc ...) induce a slight overconsumption compared to the same engine which would not be equipped with depollution. As a result, even though the current block yield is better than older blocks, actual consumption has not fallen significantly.


Yes and let's add (in others ...):

a) all the "comfort" electronic equipment, a current alternator is 2000-2500W ... it was 400-600W in the 90s ...
b) All the active safety equipment (abs, air bag, dtc) ... If the air bag and abs count very little, the DTC will calculate and permanently correct the stability by braking = overconsumption and premature wear
b) quasi-systematic series air conditioning now
c) wider tires generally (except on electric vehicles, it's HS but look at the original size of those of the BMW i3)
d) and above all an average mass of cars linked to these constantly increasing "comfort and safety" improvements

So if a car of 60 70 cv 90 years was doing both conso (and performance) than one 90-100 current cv it is for all these reasons ... but the comfort was not the current one and she smoked slightly more, too!

For the longer term evolution, I found this interesting picture on the Argus website: http://www.largus.fr/actualite-automobi ... 57388.html

Too bad it lacks a lot of data ... but it gives a good idea of ​​the evolution ...

la_voiture_moyenne8.jpg
the_main_carrier8.jpg (98.42 KIO) Accessed 2074 times


And the evolution of the consumption of gasoline cars in the United States since 1950 (hence the unit in km / L and not L / 100 km), the strong evolution took place during the 80 years especially (democratization of the injection) ... but 10 km / L it remains high for us ... After neither standards nor vehicles are the same ...

essence090308.gif
essence090308.gif (10.88 Kio) Viewed 2074 times


We can also look at this report of the National Assembly: http://www2.assemblee-nationale.fr/documents/notice/12/rap-off/i2757/(index)/depots/(archives)/index-depots
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Re: Economic analyzes on the passage from 90 km / h to 80 km / h in France ...




by Christophe » 24/05/18, 01:33

nico239 wrote:I like to reason with the absurd.

And why the speed would not be limited to 50 for example on all roads?


Because a thermal car will consume as much 50 100 km / h and that time (vehicle and human time ... in particular) has a cost also ...

So there is no interest in doubling the journey time for an identical consumption ... When we all ride the electric debate may be different! But we are far from being there!
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Re: Limitation to 70 km / h on the device




by sen-no-sen » 24/05/18, 11:01

Christophe wrote:No, the consumption of a thermal car goes up at low speed so it is not the same reasoning as the conclusion of Auto Plus ... I said above: this reasoning that corrects the consumption by the efficiency n is not valid with electric and hybrid ...


My remark concerned the notion of aerodynamics: whatever the type of vehicle is the same problem: the resistance of the air increases with speed ... unless you have a wall accelerator (MHD) ... : Lol:
Electric cars are obviously subject to this problem, which supports my claims on the facts that it is not possible to consume less at 130 than 110 km / h.
Concerning the source of the graphic on the electric cars, it is a compilation coming from site of constructors, ex of tesla:
Image
https://www.tesla.com/fr_FR/blog/model-s-efficiency-and-range
It is found that the optimal speed on the Tesla S is 25 MPH at the hour is about 40km / h ...
Of course, its optimal speeds are more important for thermal cars which, as you say, consume more at low speed, especially because of the staging of the gearbox and all the more so when driving at low speed.

Otherwise at the level of the methodology:http://theses.univ-lyon2.fr/documents/getpart.php?id=lyon2.2007.chevasson_g&part=129571
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