[T2] electronic thermostat

[accessys at smart.net]

and any failure mode should be FULL open the same as VW did.

Bob

On Fri, 18 Apr 2014, Joe St Croix wrote:

> Date: Fri, 18 Apr 2014 10:59:04 -0400
> From: Joe St Croix <spotop at gmail.com>
> To: Christophe Guilbert <cguilbert at picasso.ucsf.edu>,
>     Type 2 List <type2 at type2.com>
> Subject: Re: [T2] electronic thermostat
> 
> An over ride switch.
> If there will be an lcd display showing the temp, the ability to push a 
> button to open or close the flaps as needed in case of an emergency.
>
> -----Original Message----- From: Christophe Guilbert
> Sent: Thursday, April 17, 2014 10:43 PM
> To: Type 2 List
> Subject: [T2] electronic thermostat
>
> Hi guys , a while ago , I announced that I will do an electronic
> thermostat.
> I did a prototype using an Arduino nano , a servo motor and a digital
> temp sensor which control the servo.
> The electronic and servo are located in the engine compartment. Servo
> and arduino are voltage regulated against voltage fluctuations. The
> flaps are moved  by the servo motor using a regular bicycle cable which
> goes through the bracket which was holding the mechanical thermostat .
> So far it looks really good, I will post everything once this project is
> complete (soon) with details and video.
>
> Meanwhile I would like some ideas/feedback about the way I should open
> the flaps according to the temperature.
>
> I have mainly 2 problems.
> 1) Where to put my temp sensor.
> 2) Flap opening(%) curve according to the temperature (which is
> Dependant to 1)
>
> So far , I wanted to install my (waterproof) temp sensor to the bracket
> holding (the now missing ) mechanical thermostat , however the optimal
> reading to open the flag of my sensor will be different than the one
> provide by the mechanical thermostat. why  ? well correct me if I am
> wrong but I suspect that since air is a great thermal insulator, most of
> the heat received by the mechanical thermostat will come trough  its
> metal mounting bracket which is attached to the engine. I probably will
> have to take care of that while programing point 2)
>
> Now , I also have this other idea. Instead of using the thermostat
> bracket to hold my temp sensor , I can install an (none contact)
> infrared temperature sensor just on the top  of cylinder III (by
> drilling a small hole trough the tin to accommodate the sensor) and use
> that temperature to control the flap. In this event what, should be
> point 2) ???. I like this idea because I the control of the flap will be
> the reflection of areal  cylinder temperature. I can also attach an LCD
> display to my Arduino to monitor real time the temperature and even put
> an alarm using a buzzer in case the flaps stay open too long , I also
> wont need any thermocouple temp sensor attached to the spark-plug anymore.
>
> Also , arduino has an endless possibilities , I would like to use it as
> a mini computer for my bus later on .
> I plan to check the voltage , RPM, oil temp , cyl temp, etc ....
>
> If you guys dream to add something to my project , what would it be?
>
> Thanks for any discussion.
>
> Chris
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