Remember that there are dynamic forces involved as well. You have to accelerate the valve's mass (and, say, half that of the spring, if you have one).
Exhaust valve forces
- Thread starter tigtorch
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Don't waste too much time on guestimating the pressure. If you had somehow underestimated the pressure (which is rather unlikely, as even 3bar is way too much for slow running and low compression) the valve will open a little bit later when pressure has fallen a bit.
And if it doesn't, you can still throttle the carburetor, lean the mixture and most efficient: lower the effective compression ratio by simply leaving the intake valve open during the first part of the compression stroke. The solenoid makes this very easy.
The last allows you to simulate some kind of atkinson cycle as well
I'd calculate with 5 bar, mostly because I'd be very curious about how the exhaust sounds of the small engine when opening (nonsensically) far from bottom dead center at low rev. There should be spectacular flames when running rich, too.
And if it doesn't, you can still throttle the carburetor, lean the mixture and most efficient: lower the effective compression ratio by simply leaving the intake valve open during the first part of the compression stroke. The solenoid makes this very easy.
The last allows you to simulate some kind of atkinson cycle as well
I'd calculate with 5 bar, mostly because I'd be very curious about how the exhaust sounds of the small engine when opening (nonsensically) far from bottom dead center at low rev. There should be spectacular flames when running rich, too.
As I have very few options as far as solenoids that will fit (either physically or my budget) I intend to not spend too much time calculating this force. I was hoping it was smaller than it is but now that I now what I am facing I intend to use the very last few thousandths of the plunger movement, where the force is the highest, and hope for the best. My valves are very big for the bore and only need open a very little distance.
I will have an operating (hopefully) example in a few days and will post pictures.
I will have an operating (hopefully) example in a few days and will post pictures.
Art K
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Tigtorch,
If you want to learn about selenoid operated valves then you should look up a man I've seen at the NAMES show since I started going, David Bowes. Here are a few websites I found in a 2 minute search, my advise don't try to reinvent the wheel, check out these sources of information.
http://rbowes1.11net.com/dbowes/
http://groups.yahoo.com/group/EVIC-111/?v=1&t=directory&ch=web&pub=groups&sec=dir&slk=16
[ame]http://www.youtube.com/watch?v=GGnT58gRAz8[/ame]
http://hackaday.com/2009/06/24/evic-engine/
Art
If you want to learn about selenoid operated valves then you should look up a man I've seen at the NAMES show since I started going, David Bowes. Here are a few websites I found in a 2 minute search, my advise don't try to reinvent the wheel, check out these sources of information.
http://rbowes1.11net.com/dbowes/
http://groups.yahoo.com/group/EVIC-111/?v=1&t=directory&ch=web&pub=groups&sec=dir&slk=16
[ame]http://www.youtube.com/watch?v=GGnT58gRAz8[/ame]
http://hackaday.com/2009/06/24/evic-engine/
Art
