Date: Sat, 16 Nov 2013 23:04:33 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
<BAY403-EAS989E43661B4333C6B55E34A0FA0@phx.gbl> <5287E41A.70601@gmail.com> <5287E71D.9090100@turbovans.com>
In-Reply-To: <5287E71D.9090100@turbovans.com>
Subject: RE: Arduino and Vanagons
Date: Sat, 16 Nov 2013 23:04:31 -0500
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I used the ignition dwell thing as it makes sense to mechanic familiar with
them. It all has to do with "time" A circle has 360 degrees. For the
distributor on a 4 cylinder engine that gives 90 degrees for each cylinder.
So a 45 degree dwell is really a 50% duty cycle.
As we make the transition to non-DC electricity or any nonlinear electrical
issues many measurements revolve around trigonometry. We look at frequency
and phase shifts for capacitive and inductive circuits. Look at lighting
ballast next time you are at home depot note some are marked as normal power
factor, some high power factor. Yes in industrial settings we have to pay
attention to that stuff. Too much phase shift and the power company may get
upset. Switching type power supplies like those used in inverters are
becoming very common. All trigonometry. These can cause all sorts of havoc
even in our DC vans. Yes a cheap inverter used while driving can toast an
engine ECU. As a tech we need to be aware of these considerations. We also
need to know the difference between apparent power, and true RMS. Newer
vehicles with all the smart systems can really be affected by outside stuff.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Scott Daniel
Sent: Saturday, November 16, 2013 4:44 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Arduino and Vanagons
minor correction ...waterboxer injectors don't turn on 'every revolution' ..
They are triggered continously in pulses...or in 'injector on time, in
milliseconds of duration.'
- as one big 4 part injector too btw. Called batch fire.
Not sequential, not timed to engine or piston position.
Somewhat crude.
Dwell in distributors is the amount of angle in degrees that the points are
closed..
during which time a field is building up in the coil. Smaller points gap
equals larger dweel angle..and more charge time of the coil primary circuit.
At the instant the points open, the field collapses, inducing the large
secondary voltage that fires the spark plugs.
I appreciated the PWM description for the Idle Valve .
Very clear,
thanks !
Scott
On 11/16/2013 1:31 PM, JRodgers wrote:
> Dennis,
>
> Thanks for that comment. It better explains things I never quite
> understood about "Dwell".
>
> John
>
> On 11/16/2013 10:37 AM, Dennis Haynes wrote:
>> As with many digital control circuits, things are not modulated but
>> rather turned on or foo with the "on time" or ratio of on to off time
>> achieving the required results. The injectors are the primary example
>> of this. They turn on once every engine revolution. The ECU changes
>> the length of this "open time" to control the fuel delivered. If they
>> were on all the time the duty cycle or pulse would 100%. Thing of
>> dwell back in the ignition points days.
>> There we used the angle to set the points. The longer the dwell, the
>> better the coil could charge before we opened the circuit to make the
>> spark.
>>
>> Dennis
>>
>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>> Behalf Of JRodgers
>> Sent: Saturday, November 16, 2013 11:13 AM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: Re: Arduino and Vanagons
>>
>> Uh, I seemed to have missed something in this discussion What is
>> a/the PWM?
>> It just doesn't come to me.
>>
>> Thanks,
>>
>> John
>>
>> On 11/15/2013 10:03 PM, Brett Ne wrote:
>>> GoWesty emailed back and declined to share their information, citing
>>> "that data is proprietary". It really isn't, just as knowing the
>>> expected output voltage range of a healthy voltage regulator isn't
>>> proprietary. Oh, well, it was worth a try...it just means a little
>>> more
>> work on our part.
>>>
>>>
>>> So, here's what we need to know:
>>> * The PWM duty cycle being feed to the idle air valve when:
>>> --the engine is cold, the starter is engaged, and the coil is
>> shorted
>>> --the engine is cold & running
>>> --the engine is fully warm & running
>>> --the engine is fully warm & running with PS operating
>>> --the engine is fully warm & running with AC on
>>> --the engine is fully warm & running with PS operating and AC
>>> on
>>> * The current draw from the idle air valve at a known duty
>>> cycle.(or feed it straight 12v and measure the current draw.)
>>> * The base voltage and the peak voltage coming from the Hall sensor
>>> The above items will need to be done by someone with a scope and a
>>> healthy ICU & idle air valve(and PS & AC).
>>>
>>> * Which connector, 4/ST2 or 11/ST1, supplies the PWM power to the
>>> idle air valve. (and confirm that whichever supplies the PWM power,
>>> that the other is a ground connection.)
>>> * What is the voltage at the coolant temperature sensor when cold
>>> and when
>>> 160 F.
>>>
>>> I think that this would provide all the information needed to design
>>> the circuitry and program the microcontroller to drive the idle air
>>> valve.
>>>
>>>
>>>
>>> And once a prototype is built, we will need a vict-- I mean
>>> volunteer-- to connect it to their rig for testing & fine tuning.
>>> Preferably in the Portland, OR area.
>>>
>>>
>>> --
>>> Brett in Portland, OR
>>> "Albert" '82 VanFox I4 Riviera
>>> .
>>>
>> .
>>
>
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