Dip-stick heater test -- no go

<div class='quotetop'>QUOTE(c4 @ Jan 31 2007, 10:53 AM) [snapback]383315[/snapback]</div>

That is pretty much where I am. I looked at the Schmitboard prototyping system for surface mount and then learned about using film in a printer to make a mask for printing my own boards. I'll probably go with a $50 Schmitboard kit initially (good and fast) and later, when my wife isn't looking, try the film-exposure approach.

<div class='quotetop'>QUOTE(c4 @ Jan 31 2007, 10:53 AM) [snapback]383315[/snapback]</div>

Based upon the Japanese warm-up that seems focused around 40C, I use that as my initial control point. I have a power-on delay that avoids the race-condition of "0" volts (infinitely hot). Once it reaches 40C, I ramp up quickly to 70C. I have not thrown any codes waiting to 40C. When I was using 30C, I threw one code and below 30C, it throws a code all but instantly.

I have a Graham scanner so I can monitor the vehicle reported temperatures and if needed, clear any engine and hybrid vehicle codes.

<div class='quotetop'>QUOTE(c4 @ Jan 31 2007, 10:53 AM) [snapback]383315[/snapback]</div>

So far, waiting until I read 40C seems to work reliably.

<div class='quotetop'>QUOTE(c4 @ Jan 31 2007, 10:53 AM) [snapback]383315[/snapback]</div>

I used to just switch in the bias resistor-diode network without a ramp. The automated version has a one second polling interval for adjusting the PWM pattern with single step increments. I'm not sure the ramp is necessary but extensive testing will answer the question.

<div class='quotetop'>QUOTE(c4 @ Jan 31 2007, 10:53 AM) [snapback]383315[/snapback]</div>

Hobbit in the "Prius_Technical_Stuff" group was interested in this. I'll see if I can reproduce this and forward it to him. This could be useful. The trick we've used is to get 'autostop' and then put the car in "N". This inhibits power to MG1 so it can't start the ICE. I don't know how long we can go this way before it throws a code.

<div class='quotetop'>QUOTE(c4 @ Jan 31 2007, 10:53 AM) [snapback]383315[/snapback]</div>

Sounds like fun. I've got the maintenance manuals and I remember reading about some of the 'tricks' to force the ICE on to support emissions and other testing.

Bob Wilson

 

Hi folks,

The brass board works well enough that I'll use it the rest of the season until I build the permanent replacement. I can easily build extra copies if there is an interest. Based upon what I know, they should run about $100-200 each.

If you have an interest, send me a PM. This will give me an idea of how many parts to order and the technology to use. I'm not after deposits, just contact information and a 'request for a quote.'

SPECIFICATIONS:
1) Thermistor monitor and adjustment system.
2) By default, adjusts temperature to 70C after reaching 40C. (note 1)
3) By default, limits temperature adjustment below 82C. (note 1)
4) By default, start delay is 5 seconds. (note 1)
5) Records temperature adjustments for playback.
6) Upper, lower temperature settings and start delay can be changed.
7) Operating range -20C to 85C.
8) User installable without special tools

Note 1: Default parameters are specific for NHW11, USA Prius.

The web page has the brass board source listing:

http://hiwaay.net/~bzwilson/prius/pri_temp.html

Bob Wilson