Date: Sat, 16 Nov 2013 22:15:09 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Arduino and Vanagons-The fuel injection handbook.
Content-Type: text/plain; charset="us-ascii"
Get this book
http://www.amazon.com/Bosch-Fuel-Injection-Engine-Management/dp/B0029OVEX2
A lot will make sense. On the Vanagon like most engines except for extra
pulses while starting the injectors "batch" fire once every revolution, or
every other time the ignition fires. The fuel hits and then vaporizes
immediately off the head parts. This boil off leaves residues such as carbon
and other stuff in the intake tract. Besides improved fuel quality and
design the next fix for this is the "sequential" injection systems. These
time the delivery to the cylinders to reduce the time the fuel sits in the
manifold and boiling off. Much of this is becoming mute as we are now
transitioning into direct injection systems for gasoline similar to Diesel
use. The next future set should be dual mode engines where they will
transition from spark ignition and tight mixture control to compression
ignition and extremely lean mixtures getting diesel like advantages running
gasoline without the diesel pollution disadvantages. Many industrial engines
use combinations of natural gas and Diesel to get these benefits. What
diesel head has not heard of propane injection?
Are we having fun yet?
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Scott Daniel
Sent: Saturday, November 16, 2013 10:00 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Arduino and Vanagons
a few more thoughts..
OK...the injectors fire when there is an ignition pulse , all 4 of them.
So ....for the one cylinder that happens to be just before TDC with the
spark plug firing ..
that cylinder's injection pulse is actually late for that cylinder.
the other 3 cylinders .....the injector squirt will be at some other phase
of the 4 stroke cycle.
It works out that things are moving fast enough ..( I read this years ago in
some paper discribing the system ) that injecting into the intake manifold
happens continously in pulses...and it all works out.
and they are not actually timed to intake valve being open say ..
or perhaps one cylinder is . .
while the other injector pulses happen in the intake runners at various 'not
intake valve opening' times.
That's a more elaborate way of saying what I meant when I wrote that
injection events do not occur in a 'timed to engine position' way.
Scott
On 11/16/2013 5:28 PM, JRodgers wrote:
> Wow!
>
> Thanks Mark, for even more illumination on how things work in our
> mechanical beasts!
>
> This is all great stuff for those of us that don't know!
>
> John
>
> On 11/16/2013 4:24 PM, mark drillock wrote:
>> The injectors do fire in time with the engine position. All 4
>> injectors fire once every hall pulse which happens every 180 degrees
>> of crankshaft rotation, so twice for every engine revolution. The
>> ignition spark is by definition according to engine position and the
>> fuel injectors fire based on the same triggering event that the
>> ignition uses. Of course the ECU adjusts the ignition point to
>> optimize it. The ECU also cuts off the injection pulses when
>> conditions dictate, such as going down hill with your foot off the
>> gas, assuming your throttle position switch is working.
>>
>> Mark
>>
>> Scott Daniel wrote:
>>> 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.
>>>
>>>
>> .
>>
>
