A little Sleeve Valve Engine

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sorveltaja:
Achim, that reed switch is something, that I've also considered for my test engine, but not being sure would it last :scratch:.

It sure is tempting option, as they are more commonly available than certain hall-switches.

Interesting to see, how it works with your engine :thumbup:.

madjackghengis:
Achim, congratulations on an excellent build of a rather difficult design that has many potential pitfalls. With regard to your experience with hall effect sensors, they are extremely sensitive to impedance, and require rather exact current limiting circuits which means you have to either build your own transistor circuit for power through the coil, or have the sensor's matched to an ignition circuit with the parameters well matched. I am still up in the air as to what ignition I will be using on my radial engine build, I have an option of using an auto ignition unit from a Mallory "unilite" distributer, which will demand 12 volts, a ballast resistor to control the current, and making a disc or sleeve with cutouts, to activate the LED sensor, and either build and advance unit, or operate it entirely manually for advance. I am also considering building a magneto for the engine, but I'm not sure I can get the power necessary out of such a small unit. I also have an ignition kit I built, which is designed to convert points to electronic, and with it, one can use micro switches, as the trigger current is too small to burn out the contacts quickly, as they do if used directly. If you know the actual voltage delivered to the hall effect switch, you can put in series, a resistor that will reduce the current substantially, but test to ensure you don't lose reliability of the sensor. The type of transistor trigger circuit that drives the coil has a great effect on the load on the sensor, and is drawing too much current through something that is just supposed to be a trigger, and not a component of any substantial power. I am impressed with your idea of the reed switch, and that it works reliably may mean that is what you stay with, but if you wish to pursue the hall effect ignition, I'd be happy to assist you in figuring out circuitry, I just have to pull it out of some fifteen years of ignoring electronics, and get back to my books. I'm having to do this anyway for my own engine build, and when I get to it, I will be posting it, along with the rest as I go. If you want to do something with it in the mean time, I will jump ahead, and take a good look at the electronics, as I have to eventually in any case. Regardless of all that, you have done an excellent job on a difficult build, and done so very impressively. Md Jack :thumbup:

Joachim Steinke:
Jack, many thanks for your offer of help and advice.

By the way, the reed switch was not a longer lasting solution too. After several good running periods I got new problems with temporarily contact bonding. Maybe there are several reasons for this failure, still too excessive current on the micro contacts of this very small reed type, too little magnetic field intensity and perhaps too excessive vibrations under this circumstances.

So I turned back to the hall problems, spend some time on understanding the working principals of the transistor circuit and was also looking for help in my German CNC Forum too. It soon becomes obvious, that the ignition module (I took from a website) is a very primitive layout. The creator hadn’t turned any attention on keeping away high-voltage influences from all the sensitive parts. I would need some components like a Zener diode in the main transistor power line and maybe a fast recovery diode in the hall sensor supply line too. An additional alternative could be to separate the hall sensor completely from the ignition coil area and transmit the trigger signal via an opto-coupling device. Such a fully galvanic separation is common in professional vehicle ignition modules.

Anyway, all the nice things I would need to enhance my ignition module where naturally not available at my local store. So I had to make an order first and it would take same days until I can progress with the hall unit complex.

In the mean time I don’t wanted to trust in further electronic experiments only…ha ha ha…..

So I put some pieces of Dural on my machinery…..

and after a couple of horizontal……

and vertical milling actions…….

and some small components made from bronze….

and Polyamid…..

…….finally I managed to get a good old fashioned ignition switch.

For sealing the housing cut-out of the little ignition camshaft from any oil leakage I arranged an o-ring gasket between the shaft and the base plate tunnel, I don’t have enough space for a normal rotary shaft seal here.

The separate ignition switch plate has a cylinder clamp mounting…..

and can be rotated around the base plate about +/- 20deg.

Now it’s quite comfortable to change and adjust the ignition timing.

As I will use the existing transistor device for driving the ignition coil, the bronze contacts don’t have much current to handle and a smoothing capacitor is not necessary too.

This pure mechanical system is working fine, here comes a new testing video I made this afternoon.

Sorry, some unsteady camera movements here, but I used a new digi cam and have to look for some new cutting software now as my old system don’t like the new MPG format very much. So the complete video sequence is taken directly from the camera and totally uncut.

http://pl-hi.de/JST/SLVE/SLVE_RUNNING_SWI_01.mpg

Good night from Achim

sorveltaja:
Achim, nice work on the new breaker points :thumbup:.

Bernd:
Only one way to describe this "simply assume" :thumbup:

Having a bit of trouble with the video. Won't play but about one second of the vid. :scratch:

Bernd

Just updated my media player. Vid works fine now. :thumbup:

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