And aerodynamics?

Tips, advice and tips to lower your consumption, processes or inventions as unconventional engines: the Stirling engine, for example. Patents improving combustion: water injection plasma treatment, ionization of the fuel or oxidizer.
eco_mobile
I discovered econologic
I discovered econologic
posts: 3
Registration: 09/12/11, 22:16




by eco_mobile » 11/12/11, 20:26

for 1 first response received to my first post here, I'm ... amazed : Shock:

It's an initiation ritual, a hazing : Mrgreen: ?

I would answer that the mistral as the initiator of the phenomenon seems to me quite "fluctuating".
the availability of a crane or gantry 1 Ton : Cheesy:

130Km / h stabilized speed seemed like a good approach to minimize the effect of natural wind. And so make reliable the actual incidence of the aerodynamic element.
And 40 € + a highway portion of 10Km more accessible to the kidam.

I had understood that automotive aerodynamics was also related to soil effects which will be very hard to simulate on a model.
rotating tires
air flowing through the engine compartment, the wheel arches ...
ground effect underbody
...

Let me continue my tests via moving vehicle + dynamic recorder ECU parameter. I would see if my measurement method is reproducible on the unmodified vehicle in these constraints.
0 x
User avatar
Flytox
Moderator
Moderator
posts: 14138
Registration: 13/02/07, 22:38
Location: Bayonne
x 839




by Flytox » 11/12/11, 21:52

eco_mobile wrote:To measure your consumption under aerodynamic stress, as long as we do not have access to wind tunnels : Mrgreen:
There is now for an 40ene of euros the kits ELM323 or elm327 + software obdII which dialogues in dynamics with the management of the engine (ECU).

With this you can memorize at steady speed
throttle butterfly opening (throttle pedal electric control)
-instant consumption
-speed
-charging engine

Since aerodynamics is predominant at high speeds, it is advantageous to measure at 130 KM / h steady speed.
Change an aerodynamic element of the car
redo a measurement

I will try to improve the aero AR of a Twingo 2 (raw and straight cut ass, by a spoiler with the famous 14 ° // airflow on the bodywork.

Have others already tried?
I just acquired an ELM327 and I tested some inconclusive free software.


Hello and welcome eco_mobile

The approach is interesting 8) . I have a little doubt about the reliability / accuracy of the conso measures of some on-board computer. Have you already done the same course several times in strictly the same conditions of road, weather, traffic, tire inflation, the same full of fuel etc ... to see if it shows you every time the same music (reliability, repeatability of the measure)?
0 x
Reason is the madness of the strongest. The reason for the less strong it is madness.
[Eugène Ionesco]
http://www.editions-harmattan.fr/index. ... te&no=4132
dedeleco
Econologue expert
Econologue expert
posts: 9211
Registration: 16/01/10, 01:19
x 10




by dedeleco » 11/12/11, 22:13

if my measurement method is reproducible on the unmodified vehicle in these constraints.

problem wind speed, variable on the course? !!
The wind direction, account, crooked changes all the whirlpools and the aerodynamics !!
a very light wind of 5km / h gives 2,5% error at 100km / h !!
10km / h 5% 15 - 7,5% 20km / h - 10% (square of the speed gives 1 / 2Dv / v in proportion)
The wind of other cars and especially trucks changes everything, and trucks abound on the highway!

So everything depends on the precision needed and have an anemometer.

I do not speak of the consumption to measure, which requires above all a constant speed perfectly, no coast, even small, etc..

Not obvious, physical measures !!
0 x
User avatar
chatelot16
Econologue expert
Econologue expert
posts: 6960
Registration: 11/11/07, 17:33
Location: Angouleme
x 264




by chatelot16 » 12/12/11, 02:10

car hung by a cable on a mistral day ... it's the most ridiculous

a car is made to roll! it seems to me most significant to measure it when it rolls

the wind disturbs the measurement ... just choose days with low wind ... it's easier than waiting for a windy day that will not even be constant!

I share the doubts about the behavior of the engine and the measurement of its consumption, but there is more simple:

launch the car at high speed and put in neutral: record the speed during the slowdown: the slightest improvement of aerodynamics will be visible

even if the road is not perfectly flat, just try it in the same place

if there is a way to connect a computer to the car to take advantage of its speed sensor it would be nice

I used something else: a sensor GPS USB on a laptop: it records very well the movement of the car during the slowdown, without anything to plug on the car
0 x
dedeleco
Econologue expert
Econologue expert
posts: 9211
Registration: 16/01/10, 01:19
x 10




by dedeleco » 12/12/11, 20:43

Very, very good idea to measure the change of the slowing of the car in freewheeling, with various means, GPS, even without a computer, just reading at 1km near with stopwatch, counter, account turn on a wheel, like for a bike (magnet and small commercial electronics) , or even a small anemometer measuring the speed of the wind relative to the car, essential parameter, which makes it possible to correct the variations of the local wind, without any fatigue.
For the very simple and complicated types, see:
http://fr.wikipedia.org/wiki/An%C3%A9mom%C3%A8tre
http://en.wikipedia.org/wiki/Anemometer

With a crosswind, we can see if the result of the change is not changed.
0 x
eco_mobile
I discovered econologic
I discovered econologic
posts: 3
Registration: 09/12/11, 22:16




by eco_mobile » 19/12/11, 21:54

Ok tested software (paid version 15 €)
therefore 4 simultaneous curves recording capability.

but obviously the norm ... is not correctly implemented by renault so there are fixed values.

but with butterfly opening, engine load, engine speed, and short correction of the injection there's enough to do.

I also changed my rear rims from 5.5J ET 29 >> 5.0J ET 45.
put tires in 165 instead of 175 (admitted for my car)

therefore 0,5 inch narrower 5.5> 5.0
and 16 mm further back from the bearing face (ET29> ET45).
So now rim and rear tires are recessed in the rear wheel arch. So AR wheel fairing is easy to do because dishes!

As a result, the contact point of the tire moved 16mm towards the center. This changes the rear track width only. But the outer side is back 16 + 1/2 (rim 5.5> 5.0) => 16 + 6.5 => 22,5mm.
The internal flank only retreats by 16 - 6.5 => 9,5 mm.

On the front I did not dare, because the point of contact of the tire is targeted by the geometry of the wheel pivot : Mrgreen: except that the opportunity to mount the snow tires will also move from 175 to 165mm wide. Quit to do :P
0 x
Surfeurseb
I understand econologic
I understand econologic
posts: 79
Registration: 01/12/05, 11:51
Location: Britain
x 1

to revive the subject ...




by Surfeurseb » 16/12/13, 22:34

I've been thinking about it for a long time, and finally it should not be such a bad idea, because others have already done it:
the boat tailing

It consists of profiling the rear of the car to the maximum, to reduce the drag of base, very important in the aerodynamic balance of our cars. For practical reasons, no manufacturer can afford to go that far ...

http://ecomodder.com/forum/showthread.php/project-geo-metro-boat-tail-prototype-15-mpg-10691.html

It is an American site, as they are really capable of the best, as the worst (personal opinion).

15% saving on conso noticed, obviously especially in course of stabilized speed.

My idea was to make the same appendix, but totally removable and without any other consequences on the car: an inflatable structure, transparent, which would not even hide the traffic lights.
To go further, I must find information on the realization of inflatable structure, type PVC, or beach toy for example.
Attachment by suction cups and securing by cables, inflation ... as one can, or automatically by scoop (paragliding style), with deployment from a certain speed.

I like it, and I can imagine the faces of the people I might meet driving my "drop of water".
0 x
User avatar
chatelot16
Econologue expert
Econologue expert
posts: 6960
Registration: 11/11/07, 17:33
Location: Angouleme
x 264




by chatelot16 » 16/12/13, 23:19

I had the same idea for a long time: gonglable pointed ass

the pvc plasticized kind of beach toy is not very strong especially transparent: to make more solid it takes the nylon cloth coated pvc style tarpaulin truck

to make transparent there is better: the polyurethane: I saw a dirigible balloon completely transparent, the electroplume that had been used nicolas hulot: one of these electroplume became the prototype of a much more powerful machine
http://www.a-nse.com/fr/a-n400/
this 0,4mm polyurethane transparent envelope has seen all the colors ... I worked for a while at home

I know the welding of this kind of material, but I do not have the financial means to go to the realization

this inflatable tip would be convenient: when you deflate it could be clinging to the roof of the car with a rope that pulls the tip forward: no extra space in the city

and on the main road the congestion of this point would have no inconvenient

often the car has a rear that retracts too quickly: it picks up at the roof so the inflatable ass must be fixed on the car at the roof and rebuild all the shape back

the inflatable solution makes it very light

polyurethane is stronger than pvc, scratches less and remains better transparent, so good visibility through
0 x

Back to "Special motors, patents, fuel consumption reduction"

Who is online ?

Users browsing this forum : No registered users and 217 guests