Search found 24 matches

by superlen
Thu Feb 06, 2014 9:15 pm
Forum: General FOSS EMS
Topic: determine engine load with MAP or MAF??
Replies: 23
Views: 73824

Re: determine engine load with MAP or MAF??

You'll need to revisit some physics. :) Namely the ideal Gas Law..... PV = nRT Understand this & you can write a function similar to FI_Air_Mass(.....) below. This function takes pressure (P) & volume(V) & intake air temp (T) and solves for n (number of moles) using the ideal gas law and...
by superlen
Thu Feb 06, 2014 8:05 pm
Forum: General FOSS EMS
Topic: determine engine load with MAP or MAF??
Replies: 23
Views: 73824

Re: determine engine load with MAP or MAF??

Settra, It looks like from your original post you have started to figure it out. Here's a really good book that covers a lot of this as well. There's nothing in here that you can't get form this forum or the people frequenting it, but the book is organized really well & will help solidify your t...
by superlen
Fri Sep 27, 2013 11:51 pm
Forum: General FOSS EMS
Topic: AFM question
Replies: 7
Views: 11810

Re: AFM question

The plot thickens... Upon researching the ratio of specific heats I found this: "The above value of 1.4 is highly consistent with the measured adiabatic indices for dry air within a temperature range of 0 to 200 °C, exhibiting a deviation of only 0.2% " Therefore the ratio in the earlier f...
by superlen
Fri Sep 27, 2013 11:38 pm
Forum: General FOSS EMS
Topic: AFM question
Replies: 7
Views: 11810

Re: AFM question

LOL. Don't hold back, Fred. Tell us how you really feel. :) I agree that there are much better options today, but what I'm working on needs to support my old junky AFM too. I did find the equations to calculate what the delta force on the flapper vane is when the density changes. Here is the relevan...
by superlen
Fri Sep 27, 2013 10:25 pm
Forum: General FOSS EMS
Topic: AFM question
Replies: 7
Views: 11810

Re: AFM question

After thinking about this some more, here are my thoughts. Cold dense air will definitely push the vane farther than warm air at a given flow rate. However, the delta change reflected in the vane position is very small compared to the delta change when the actual flow rate varies. Think of it as a 1...
by superlen
Fri Sep 27, 2013 3:23 am
Forum: General FOSS EMS
Topic: AFM question
Replies: 7
Views: 11810

AFM question

I have a question about the old style Vane air flow meters. It's call an air flow meter not mass flow meter. However, will the temperature of the air change the reading any, assuming the same cfm flowing through it? The reason I wonder is that cold air flowing through the meter will have more mass t...
by superlen
Mon Sep 16, 2013 2:24 am
Forum: FreeEMS Hardware Dev
Topic: Ideas For High Side Drivers
Replies: 7
Views: 34994

Re: Ideas For High Side Drivers

On Semiconductor NVC8460 6A High side switch. Fully protected, short circuit, thermal, ect. Has diagnostic feedback for Open load and such. 3.3 or 5v input I haven't used it yet, but have it on a current design & I should have pcb layout done this week. I'm just using it to fire an external fuel...
by superlen
Mon Sep 16, 2013 2:14 am
Forum: Pit Lane
Topic: Standalone Idle Valves
Replies: 9
Views: 25585

Re: Standalone Idle Valves

I'm assuming the two wire valves are just a pwm input.

One side +12V, the other pwm output by a suitable fet to GND.

Is this correct?

Lenny
by superlen
Thu Aug 29, 2013 5:43 pm
Forum: Jaguar
Topic: Jaguar 0.4-alpha over voltage clamp trace routing mistake
Replies: 4
Views: 8819

Re: Jaguar 0.4-alpha over voltage clamp trace routing mistak

Good point on the open source confusion factor. I can see were if the schematic is showing one pinout and the datasheet is another, someones going to be thinking WTF. Of course it would have to be the part that takes out the micro instead of some transistor driving an led or something cheap. I had a...
by superlen
Thu Aug 29, 2013 3:16 am
Forum: Jaguar
Topic: Jaguar 0.4-alpha over voltage clamp trace routing mistake
Replies: 4
Views: 8819

Re: Jaguar 0.4-alpha over voltage clamp trace routing mistak

Bummer on the footprint Andy. That's burned many a pcb designer, myself included....repeatedly. :) So at least you know you have company and that it will happen again in the future. Sometimes, you can just flip your part upside down, or upside down and rotate 120 degrees to at least get your prototy...