Author Topic: A little Sleeve Valve Engine (Read 99227 times)

Joachim Steinke · « **on:** December 18, 2009, 09:15:10 PM »

Hi to all,

today I want to give you a first survey about my actual project.

I aim to update this report from time to time, but not being a native speaker, writing relatively elaborated posts in English takes a lot more time for me than the activities in my German forums. And for the rest, a little time has to be left for machining all that things….ha ha ha…..

So I hope you understand if continuance might come sparsely

Building a miniature 4 stroke engine was on top of my to do list for a long time and in the last weeks I finitely designed the plans for a little 4.1 ccm motor. For me such a project has to have always a little thrill in it….ha ha ha…. so, to make things more complicated I choose a special design of charge changing. The engine will operate with a sleeve valve system, I think most people here would know this type of timing from the famous Bristol Airplanes build around the time of WW II.

This type of engines had been already build in perfect miniatures from such experts as for example Brian Perkins with his 9 cylinder Aquillia and Tom Pasco with a 3 cylinder radial of own design. That’s a class of craftsmanship I am far away from, so I keep it simple start my first engine with a single cylinder type following my own design and my limited abilities.

The basics are:
stroke 16mm, bore 18mm, capacity 4.1ccm, compression ratio 6:1, spark plug ignition via Hall Sensor module, lubrication by gear oil pump, air cooling of cylinder and head.
Over all sizes engine block: width 39mm, length 54mm and height 90mm.

And here are some of the now completed drawings:

This is a section from the right side

And some details of the inner structure

The oil pump

And the oil distribution system

The material composition of the stroke garniture is: piston, head, outer cylinder and piston rings are made from spheroidal graphite cast iron (GGG60) and the moving sleeve from high strength free cutting steel (ETG100), the crank- and camshaft are also machined from this steel.

The engine block, the connecting rod and most of the other parts will be made from aluminium 7075 and the bush bearings will be made of bronze.

End of Part one

Joachim Steinke · « **Reply #1 on:** December 18, 2009, 09:16:20 PM »

Part Two

The sleeve valve or otherwise said the cylinder sleeve is driven by a little ball of hardened steel sliding in a hardened cylinder which is mounted in the camshaft gear wheel.

Here is a more detailed graphic of the port function:

For a convenient check of the pre calculated in- and outlet port timing, which follows an elliptical curve on the circumference of the cylinder, I made an CAD animation of the involved component, you might take a look at a little sample video here, things become a lot more obvious then:

http://pl-hi.de/JST/SLVE/SLVE_PORTS_02.wmv

I just began the machining, so my progress is not that far. To get “warm” with the project I started with the carburettor.

End of part two

Joachim Steinke · « **Reply #2 on:** December 18, 2009, 09:17:14 PM »

Part three

In between I completed the gear wheels, they are made of steel with modul 0.5 dimensions.

And as I will solder them on there shafts it’s better to have a running test before getting an imprecise disaster when it’s too late, but all seems good so far. This sort of testing on the milling machine is a good method for measuring the very true distance of the axle-base too, you don’t have to rely on pure calculations and can judge the last hundreds of a millimetre from the running sound.

The next part I wanted to clarify was if my design of the ignition system will work proper enough, for that circumstance would determine the further design of the engines blocks front section.

The dimensions in front of the camshaft are really small and I wanted to place the magnet for the Hall Sensor in the front cover of the camshaft bearing. So the diameter of the revolving disk with the 2x4mm neodym magnet is only 9.5mm.

An easy way to find out if the sensor will work through a 0.5mm wall of aluminium and if the triggering will do a precision angle repetition on such a small revolver is to ( I think you guess it…) make the next little running test…….ha ha ha….

But at last my doubts where unnecessary, the trigger works well with an 1mm aluminium sheet holding in the gap between sensor and magnet, the overall distance between the parts can have an amount of more than 3.5mm before the trigger “looses contact”. And the small diameter has no bad influence on the precision of the trigger point, I tested this on the lathe with a mark on the lathe chuck, very reliable results.

So work can proceed, let’s see how it will go…..

Good night from Achim

gbritnell · « **Reply #3 on:** December 18, 2009, 11:27:17 PM »

Excellent work on your engine so far. I'm glad to hear your findings with the Hall sensor. I'm going to be using one in my current project and I was trying to keep my spacing down to within .035, .89mm. Now I won't have to be so critical with my dimensions.
George

dsquire · « **Reply #4 on:** December 19, 2009, 03:04:58 AM »

Achim

Wow is about all that I can say for starters. I definitely am going to be watching for every new installment as you have time to post them. The drawings that you have made are great. It looks like you have a good start on it with the Carb and the gears already done.

Don't worry about your English, there is nothing wrong with it. I'm just glad that I don't have to reply in German.

Cheers

Don

NickG · « **Reply #5 on:** December 20, 2009, 03:56:58 AM »

Incredible work Achim. As I was reading through I thought I was going to have a lot of questions but you answered them all and the video answered the rest! It looks very complicated and I have never seen valving like that before. It's even got an oil pump which I recognised before I got down to that bit.

This is going to be some project.

Thanks for showing it,

Nick

Joachim Steinke · « **Reply #6 on:** December 24, 2009, 06:42:46 PM »

Hello to all you out there in this Christmas Night.

Monday I started with the real work on the crankcase and want to show you some pictures.

After milling the blocks to size from 7057 alloy stock I bored and reamed the pilot holes for the cam- and crankshaft bearings on the mill and taped the threads for jointing the two halves. Two of the threads contain a little aligning bush which will fix the parts precise for all further operations and naturally for the final assembly.

The concept is going from the inner parts to the outside geometry of the case, so I let an allowance of 0.25mm on each face of the blocks. The parts will not milled to final size before I have finished all the boring and facing jobs on the lathe, so the gripping marks of the lathe chuck don’t bother me.

After some hours of centering, boring and milling I got an acceptable, intermediate result, all parts are fitting very well.

So I continued with things like boring the oil system, taping a lot of left over M2 and M2.5 threads and all the rest of detailing the case.

Finally, after removing all allowance of the case sides and finishing the hole parts with water-resistant abrasive paper, steel wool and fine grinding pads the crank case is already completed.

Now I can continue with the crank- and camshaft, followed by the cylinder garniture and the oil pump. But things can go a lot more relaxed now, for the engine case is the most time consuming single component, one mistake here and the need of machining a complete new case would be the bitter consequence.

Good night from Achim

Darren · « **Reply #7 on:** December 24, 2009, 06:48:06 PM »

Good grief, that's some very nice work you're doing there

John Hill · « **Reply #8 on:** December 24, 2009, 07:43:24 PM »

Thank you Achim for showing us your beautiful work and beautiful pictures too!

sbwhart · « **Reply #9 on:** December 25, 2009, 02:07:03 AM »

Great Build Achim.

Enjoying your posts very much

Cheers

Stew

jim · « **Reply #10 on:** December 25, 2009, 02:10:01 AM »

WOW!

thats a fantastic bit of work

is that engine design also known as an "aspen" engine?? some years ago i was involved with a project involving an egine out of a bus, i think it was a six cylinder sleave valve, called an ASPEN engine??

Stilldrillin · « **Reply #11 on:** December 25, 2009, 02:13:42 AM »

Achim,

Wonderful work...... Wonderful photography!

David D

spuddevans · « **Reply #12 on:** December 25, 2009, 03:50:11 AM »

That is some fantastic work there

and a good finish right off the tool too

Tim

crankshafter · « **Reply #13 on:** December 25, 2009, 05:11:31 AM »

Achim.

1. HOLLY SMOKE
2.

3.

4. Have a Merry Christmas

Best regards.
Crankshafter.

NickG · « **Reply #14 on:** December 25, 2009, 05:54:59 AM »

Yes, amazing stuff! Loving this one!

Nick

sorveltaja · « **Reply #15 on:** December 28, 2009, 03:26:08 PM »

Achim, what is the model of the Hall sensor you are using? As the one that is suggested, for example on 5bears circuit, has became obsolete, at least here in Finland. Quite a little information is available of equivalent ones.

By the way, you have made really neat looking parts this far

.

But when you get to run that engine, that sure is going to be a thrill

.

Joachim Steinke · « **Reply #16 on:** December 28, 2009, 09:11:01 PM »

Hallo,

first of all I want to thank you for all the very kind replies.

Today I planed to building the oil pump, but at first some pictures of the housing cover which will fix the crankshafts front bearing.

I like, if possible, to machine most of the components which get a mixture of turning and dividing operations directly on the bar and leave it in the collet chuck switching this from the lathe to the mill and backwards. That saves a lot of measuring and adjusting and offers me a much higher precision than shifting the things permanently from one chuck to another.

And then came the time for the oil pump. This little brass gears are modul 0.5 type with 12 teeth and had to get 2.985mm borings to press the 3.000mm axles (hardened dowel pins) in.

The assembly was done on the late, making the pressure with the tailstock spindle.

After the press fitting the hardened axels were brought to precise length using a little cut off wheel and a grinding disk on the frontal operation to do the last finish.

Changing the tool post grinder to the front side I grinded the flat area for the fixing screw of the crank arm which is later driven by the crankshaft.

Next came the main housing of the pump.

I had prepared four little bronze bearing bushes and glued them with Loctite in there bearing seats which I had drilled on the mill in the meantime.

After the facing operations on the glued in bushings I milled the two little anti cavitation drains with a 1mm cutter.

Next steps where the borings for the gear itself, going 0.1mm deeper than the gear height of 4mm. The aimed axel clearance of 0.03mm of the gears to the housing faces will be done later by fine facing the case surface on the lathe.

As all fits very well I could turn the main body to the precise diameter for the crankcase boring and cut the grooves for the oil routes and the 1mm viton seals.

And this will become the oil intake line.

And nearly the last thing to do is to part off the pump case from the bar.

So here the finished components

and how they are located in the engine.

And this is how the assembled front bearing cover looks like.

Now I am very curios if the pump will do its purpose well….okay….we will see…..

Good night from Germany,

Achim

NickG · « **Reply #17 on:** December 29, 2009, 05:50:09 AM »

Now this is real model engineering, I'm just playing!

Great Stuff Achim.

Nick

Darren · « **Reply #18 on:** December 29, 2009, 08:39:03 AM »

Your work never ceases to amaze me

Bernd · « **Reply #19 on:** December 29, 2009, 09:51:29 AM »

Nice work Achim. That minuature pump almost looks like the oil pump used on the old VW air cooled engines.

Bernd

Joachim Steinke · « **Reply #20 on:** December 29, 2009, 09:56:56 PM »

Hallo,

@Sorveltaja, the Hall Sensor I use is the very common unipolar H501, but I think for example the Infineon Types TLE 4945 L should work here as well. Both sensors are in Germany good available at shops like CONRAD Electronics or REICHELT etc. But I don’t know if the mentioned distributors will be much help for your purchasing problems in Finland?

Today I was I little impatient and wanted to find out if the oil pump will do its job right. So I made a test, turned a small coupling axle, put the bearings in the block and filled the engine with oil.

Then I mounted the whole thing on my tool grinder where I can go up to more than 10 thousand rpm, the available speed on the lathe would be not high enough for getting informative results.

I would say it’s working very well. A good stream of oil was already delivered at some hundred rpm, over thousand the whole thing becomes real messy for the engine is already open at the top.

After closing the cylinder boring provisorily I could run the pump with more than 12 thousand for a longer period, no problems with vibrations, no ugly sounds and no increasing of temperature occurred.

So I am real happy about the first real functional, living component of this little project.

Good night from Achim

Stilldrillin · « **Reply #21 on:** December 30, 2009, 03:42:40 AM »

I am in awe.....

Lost for words!

Some wonderful work there Achim.

David D

Darren · « **Reply #22 on:** December 30, 2009, 07:32:33 AM »

You are not the only one David .... That's a fantastic engine your are designing and building there

And I can't stop looking at your tool grinder, did you ever make any plans available for it?

Joachim Steinke · « **Reply #23 on:** December 31, 2009, 04:11:45 PM »

Hallo Darren,

sorry, but detail drawings of my tool grinder are not available. I’m used to build the components directly from my 3D CAD model, so I normally don’t create special blue prints or workshop drawings.

But all the operating principles and fundamental details of the Mini Bonelle Tool Grinder are fully documented on my web site http://www.metallmodellbau.de/. So it should be no big deal to customize things to your own purpose.

Good by from Achim

Joachim Steinke · « **Reply #24 on:** January 03, 2010, 06:08:25 PM »

Hallo,

at first a little example of using the lathe as a substitute for a mill combined with a turntable.

Originally I wanted to use a simple paper sealing between the flange of the oil pump and the crank case rear. As there was still enough room between the fasting screws and the pump cylinder for a 1mm o-ring seal I choose this option by now.

But my smallest lathe cutting tool for planar use has 1.5mm width and I don’t wanted to grind a new one. So I took my small tool post grinding spindle and a little 1mm milling cutter.

Letting the lathe spindle rotate with very slow speed (ca. 50rpm) and running the cutter with 10tousand I get precise results with an excellent finish. This alternative method sometimes works much faster for me than extra putting my turn table on the mill for only one single duty.

Then today I spend some time on machining the con rod.

First I needed a fixture to hold the little rod on the turntable without using inconvenient and much too large clamps. In addition a fixture like this guaranties an always precise centring of the piece, you can turn it around without loosing any measure reference and have free access and a good sight on the things you do.

To adapt the con rod blanks to the fixture I made two precise brass bushings, one for the upper 4mm bore and the other one for the larger 5mm crank pin bearing. Below the centring bores I have two M3 threads, so the con rod can be easy turned over and fixed very convenient.

After centring the turntable to the mill axis and aligning the con rod fixture to the y-axis of the mill table (not before setting the turntable index to zero deg) things could get started.

The two blanks (one kept in reserve) are made from high strength alloy and have already got the bronze bearings assembled by press fit and are already milled to the final thickness of 6mm.

Wanting a nice radius transition going from the rod surface to the circumference of the two outer cylinders I was in need of a little ball cutter. As I don’t have a “serious” one for this job in stock (only 1mm radius is allowed here) I took some of the simple tools from the Proxxon shop and made a brass reduction insert from 2.35 to 6mm which is the dimension of my smallest milling collet.

Running this cutter with 5000 rpm worked very well and it made a good surface too.

And after milling the h-shape in both sides of the main body I finally got the con rod finished.

Good night from Achim

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Author Topic: A little Sleeve Valve Engine (Read 99227 times)