In a car with a diesel or gas engine, the engine produces vacuum which is used to boost the brake pressure so that you don't have to press the brake pedal so hard.
When I remove the enging there will be no more vacuum so I have replace that with something else.
So, I built a brake booster from a vacuum pump and vacuum sensor from an Audi A4, an old Sigg bottle that I used to have kerosene in for an outdoor stove, a contactor and the Arduino micro processor.
I use the Sigg bottle because it is red ;) and because it is aluminum. Since the car is made mostly from aluminum I want as much of the parts to be so as well.
The Arduino runs a very simple software the reads the pressure and turns the pump on and off between 600 and 800 mbar of vacuum.
The contactor, which is actually the security contactor that will be used to brake the high current circuit, will be replaced with simpler 12V automotive relay.
Have a look at the video:
Adding to my previous comment. When i got that answer i replied to my local inspector, pointing out the absurdity, that it in effect is a ban on EV-conversions. Though i do not not expect an answer.
ReplyDelete--steelneck
Something seem to have gone wrong with my first comment, so i add it again..
ReplyDeleteI have been planning a EV-conversion project, using a sportscar from the seventies. But since the rules to get it street legal was a bit fuzzy to me i wrote to Bilprovnngen (the Swedish Vehicle inspection agency) to find out what gives, describing my project in broad terms.
My local inspector could not answer me so he forwarded the mail to the central technical office in Stockholm. They took 1½ month to reply. The first person at the technical office could not answer so he also forwarded it to a third person (got the answer 28 June 2013).
Amomng other and widely known things the technical engineer Leif Johansson wrote:
If an electric driven vacuum pump replace vacuum from the motor, a new certificate of the brakes is needed.
Translated from Swedish above (Om en elektrisk vakuumpump ersätter motorns vakuum, krävs nytt bromsintyg.)
So i cannot proceed with my plans. I cannot risk a 100 thousand SEK on a car that probably never will get street legal. There is no way to get a manufacturer to write a certificate for a modified brake system. So the rule above basically says that vacuum for the brake servo must come from an internal combustion engine. You have to leave the ICE in the car and have it running just to produce vacuum for the brake servo. In effect a ban on EV-conversions.
--steelneck
Isn't it frustrating that the authorities can't give you a straight answer!
DeleteAnyhow, I have interpreted the Swedish regulations like this:
If you want to convert a newer car you have to register it as a rebuilt vehicle "ombyggt fordon". There is no other way.
In order to register it as a rebuilt vehicle you have to change not only the engine, but also the transmission and the brakes. And, if you convert the brakes, replacing the ICE with an electric vacuum pump is just a normal part of the brakes conversion.
So that is what I do:
I replace the transmission with one from a diesel. I put in larger rotors in the front (had to change the spindles in order to do that), change the drums in the rear to discs, replace the main cylinder with one with larger diameter. And add a vacuum pump.
All these add another SEK 20 000 to the project, but that way I can convert the car I want. A 2004 Audi A2!
:)
You can find most of it described here in the blog.
I read your blog with interest! I have been thinking about building an electric audi a2 for some time now, and together with my brother in law (who is an almost retired vw-mechanic) we decided today to go for it... I am living in the Netherlands, so I am not sure the strict Swedisch regulation also apply to the Dutch situation. so there is some homework in order to find out. I will follow your blog for tips & trics!
ReplyDeleteGreat Henk, welcome to the world of Audi A2 converters!
DeleteI will be happy to share what I can with you.
You should also join the facebook group Audi A2 EV as well.
In the Netherlands there are two suppliers that I think can tell you everything abount the regulations in your country. Rebbl (www.rebbl.nl) and Newelectric (www.newelectric.nl)
Cheers!
/ Peter
This is awesome!
ReplyDeleteDo you have the electrical diagraman for this? I would like to do one myself
ReplyDeleteHi Fernanda, I am sorry I missed your comment. Maybe it is not valid anymore?
DeleteAnyway, I would be happy to share the diagrams. Do you mean the diagram for the whole conversion or just for the brake booster
TSI engines doesn't produce enough vacuum and as such have electric vacuum pump. As such you can take part number from ETKA and use part number which perfectly matches
ReplyDeleteHey Friend,
ReplyDeleteCongratulation to you. I am happy after reading your post that you have posted in this blog. Thanks for this wonderful post and hoping to post more of this. I am looking for your next update.
Thanks a lot!
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