Mini diesel engine.

[minh-thanh]

you are maybe right at 45deg before tdc the pressure is quite low

You can't say: "maybe right.."
Because it's obvious , You must say : It is correct

 

[pirmin kogleck]

@ minh !
i deeply apologize ! yes you are correct!

pls dont kill me !

 

[minh-thanh]

pirmin kogleck !!

We've talked informations homemade diesel engine : Oil pump ... - and I hope it's helpful to you .

Another : About your previous comment :

@ minh than

i wnt even try to uswe ether, i want it to run without, allthough i have a lot ether athome and some model aero compression engines, i dont want to get into the ether discussion now...kerosene or nothing ! thats my goal. it must be a true diesel , not a compression ether engine ,....

With me - the general rule about diesel engines : all engines , if it injects fuel into the engine at compression stroke- whatever fuel it is, ether or not, kerosene or diesel, whatever gets the engine running is true diesel .
If you have success with this engine will you deny other engine use ether : that is not true diesel ??? and you would say engines that use ether in fuel are engines: compression ether engines ???
There's one more thing I hate: if someone says their engine or something they do is the prettiest, the smallest, the best...bla bla ..., or the world's smallest. .
Always There is someone make it better !
Think about that !

 

[pirmin kogleck]

it is just my goal to make it run as a Diesel !
in model Airplane /rc plane hobby there are so called diesels, and i think the topic was already discussed here . i just would like to have it run as a diesel like Mr. Hansen did . i used the terminology true model diesel or worlds smallest refering to model engine because when u look for just diesel injecotr or model diesel u get many other videos not related to the engine type we try to build, this is why i used this terminology ( "worlds smallest" and "true Diesel") i think it was also Mr. hansen wich used the Word "true Diesel" because if u search for model diesel , then youtube redirects you to the Rc airplane engines, wich i also do like, i have many of those Model Diesel rc engines , very small some under 0.2ccm ) those rely on the ether , but since we try to copy rudolph diesels system or more i should say the injector after Prosper Lòrange and the self ignition from diesel, i like to use True Diesel to not mix it up with rc model diesel engines...

 

[ranger]

To improve the surface finish of the pump bore, if the valve end was detachable, you could perhaps try ‘Ball sizing’ - ‘Ballizing’, whereby a correct size hardened ‘ball’ is forced through the bore to correct any taper, and improve the surface finish. Apparently to an almost mirror finish. With a softer material such as brass, perhaps an ordinary ball bearing might work?

 

[pirmin kogleck]

that is unfortunatley impossible because if the ball gets stuck there is no way to get im back out, the jhole on the bottom is only 0.5mm no chance to use such a think wire to get that ball back out . i will keep that in mind and maybe try ona test cylinder

 

[ranger]

Yes, trying to remove the ball from the bottom of a blind hole would be,’Interesting’, to say the least. But if the ‘cylinder’ was separate from the ‘valve block’, it would be a straight forward operation. Another possible advantage having a separate cylinder would be, you only have to replace the cylinder and maybe the plunger, if you wanted to try different methods of sealing, (or mess something up). Another thing which may help, could be, ‘anti extrusion rings’, either side of the ‘O’ ring, (if you can get them in the size you need).

 

[minh-thanh]

pirmin kogleck .

If I talk about " true diesel " , maybe some people will hate me including you .Sure .
So, Ok.. Let's put that aside, but remember what I said.
Back to main topic,

thanks for that info! i think i did exact that mistake that i forced tomuch out of the pump...,

This issue I talked about before, you did't read or skim through....

Hi pirmin kogleck !
If your engine has a low compression ratio and uses ether in the fuel and gives early injection time or gives early injection time with high compression ratio- about 45 degrees before TDC seems fine.
because if the O-rings are worn, the pump will still create enough oil pressure to inject into the cylinder at the compression stroke 45, 40, 35, 30 degrees before TDC, because at that time the pressure in the engine cylinder is still low. Or you can also combine the above suggestions with brass cylinders

Edit : Injection time: More precisely the time the lobe begins to contact the pump piston: 22 to 45 degrees before TDC

Please sit down and re-read what I said, if you don't understand : ask , because what I said may not be clear and my English is very bad and use google translate.
Regarding the O-rings and brass cylinders: I think you've got a pressure of 50bar, you're doing very well.
Wear problem : Like I said , don't try to put too much pressure on them , you also sit down and check the cylinders and pistons : how do they wear , why do they wear so fast ? .....
Let's make a part : lobe, motor ....combine them and the lobe will rotate at 500 , 700 ..rpm and use them to test the oil pump . If your oil pump can be ok for 10 ..15 ..min running , with medium pressure for a nice spray pattern it will be fine

 

[GailInNM]

With the assistance of other moderators and the support of forum members I have removed or edited about a dozen posts in this thread.

Some of the affected posts were not offensive but were removed or edited because they were no longer relavant as they were referencing posts that had been deleted.

Looking at the recent posts I think that this thread is back on track. Lets keep it that way so we can all learn from it while enjoying our hobby.

Thank you to all the forum members for all your t support.

I will remove this post in a few days.

Gail In NM, moderator

 

[Mechanicboy]

it is just my goal to make it run as a Diesel !
in model Airplane /rc plane hobby there are so called diesels, and i think the topic was already discussed here . i just would like to have it run as a diesel like Mr. Hansen did . i used the terminology true model diesel or worlds smallest refering to model engine because when u look for just diesel injecotr or model diesel u get many other videos not related to the engine type we try to build, this is why i used this terminology ( "worlds smallest" and "true Diesel") i think it was also Mr. hansen wich used the Word "true Diesel" because if u search for model diesel , then youtube redirects you to the Rc airplane engines, wich i also do like, i have many of those Model Diesel rc engines , very small some under 0.2ccm ) those rely on the ether , but since we try to copy rudolph diesels system or more i should say the injector after Prosper Lòrange and the self ignition from diesel, i like to use True Diesel to not mix it up with rc model diesel engines...

pirmin kogleck..

The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-called compression-ignition engine (CI engine). This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine (gasoline engine) or a gas engine (using a gaseous fuel like natural gas or liquefied petroleum gas). (Read again it does not say: injection or carburetor in these engines)

Rudolf Diesel wrote this in his patent No. 608,845, dated August-9, 1898 : My invention has reference to improvements in apparatus for regulating the fuelsupply'in slow-combustion motors, and inparticular to internal-combustion engines adapted for carrying outthe process described in my prior patent, No. 542,846, dated July 16, 1895, which process consists in first compressing air or a mixture of air and neutral gas or vapor to a degree producing a temperature above the igniting-point of the fuel to be consumed, then gradually introducing the fuel for combustion into the compressed air while expanding against resistance sufliciently to prevent an essential increase of temperature and pressure, then discontinuing the supplyof fuel and further expanding without transfer of heat.

US608845A - Internal-combustion engine - Google Patents - US542846A - diesel - Google Patents

In plain text, a diesel engine is a compression engine that causes the air to rise to a high temperature before the fuel is ignited and not how the fuel is supplied into the engine whether it goes via carburetor or injection. Nor a specific fuel since Rudolf Diesel wrote either it is solid, liquid or gas that could be fed into the engine and ignite by the heated air in the engine. So-called dual-fuel diesel engines or gas diesel engines burn two different types of fuel at the same time, such as a gaseous fuel and diesel engine fuel. The diesel engine fuel ignites spontaneously due to compression ignition, and then ignites the gaseous fuel. Such engines do not require any type of spark ignition and work in the same way as regular diesel engines.

What we choose to use injection or carburetor for diesel engine:
Heavy atomizing fuel is supplied via injection.
Lightly atomizing fuel is supplied via carburetor (Model diesel engine, diesel-powered chainsaw for example Comet, Husqvarna or Jonsered chainsaw.)

Glowplug make diesel engine easy to start up the diesel engine when it's difficult to atomize the fuel and there is not enough heated air to ignite the fuel in colder area or in winter period.

In the small model diesel engine with injector need light atomizing fuel due we need better atomizing the fuel and be easy ignited by heated air since the model diesel engine has great loss of heat than large diesel engine.

Ether in fuel has a purpose in model diesel engine: Easy to hand start engine. In fact, model diesel engine can run without ether which you can easily find in Youtube.

 

[minh-thanh]

One more thing I want to tell : I have never lapping pistons with cylinders if it has small diameter . Because the steel or stainless steel for the plunger with small in diameter ( < 3 mm ) it will bend and get stuck in the cylinder ... if it has a little difficulty moving in the cylinder . Even with the rod tool (a hard steel 3 mm , 2.5 mm, 2 mm ..) you can break it with tight tolerances
With large diameter cylinder - I have lapping piston with cylinder ?? Yes yes , only with a cylinder diameter of 16 mm . But only once or twice. And I don't like it. All - a lot of the cylinders I make for me and some friends (from 6 to 22 mm) including engines and cylinders, I always do my way: make the cylinders fit the pistons or back and I never lapping
I only rotate ,move back and forth the piston in the cylinder with oil a few turns , If the plunger actually moves through the entire cylinder with the oil but there is still a little - very little - not smooth
At this step you really have to be careful, the cylinder, plunger and oil must be really clean, a little mistake will ruin all your efforts and time.
If someone advises me: lapping plunger with cylinder has < 3mm diameter with tight tolerances. With my experience I very much doubt that
So be careful with any advice lapping pistons with cylinders if it has small diameter and with tight tolerances

 

[pirmin kogleck]

One more thing I want to tell : I have never lapping pistons with cylinders if it has small diameter . Because the steel or stainless steel for the plunger with small in diameter ( < 3 mm ) it will bend and get stuck in the cylinder ... if it has a little difficulty moving in the cylinder . Even with the rod tool (a hard steel 3 mm , 2.5 mm, 2 mm ..) you can break it with tight tolerances
With large diameter cylinder - I have lapping piston with cylinder ?? Yes yes , only with a cylinder diameter of 16 mm . But only once or twice. And I don't like it. All - a lot of the cylinders I make for me and some friends (from 6 to 22 mm) including engines and cylinders, I always do my way: make the cylinders fit the pistons or back and I never lapping
I only rotate ,move back and forth the piston in the cylinder with oil a few turns , If the plunger actually moves through the entire cylinder with the oil but there is still a little - very little - not smooth
At this step you really have to be careful, the cylinder, plunger and oil must be really clean, a little mistake will ruin all your efforts and time.
If someone advises me: lapping plunger with cylinder has < 3mm diameter with tight tolerances. With my experience I very much doubt that
So be careful with any advice lapping pistons with cylinders if it has small diameter and with tight tolerances

thanks for your thoughts...it is indeed very tricky and like i mentioned in one of my private messages Find Hansen said himself it is almost impossible to lap a such small Plunger in our Home Workshops with out machines . he said itr woill work for a short time and then it get lweaks, many times he had tried and failed and also many many people before and after him tried this and had little succes....i also believe that u are 100% right that the pump i have built has the pressure i need and it wokrs fine, it is just the thing that i want too have it sealed so the engine does not drip fuel on the wood plate and everything looks fine...i am sometimes very very picky and if something doesnt work i cant go to bed without fixing it

 

[minh-thanh]

. he said itr woill work for a short time and then it get lweaks, many times he had tried and failed and also many many people before and after him tried this and had little succes....i also believe that u are 100% right that the pump i have built has the pressure i need and it wokrs fine, it is just the thing that i want too have it sealed so the engine does not drip fuel on the wood plate and everything looks fine...i am sometimes very very picky and if something doesnt work i cant go to bed without fixing it

Because brass is soft and easy to machine .
You can easily create a beautiful brass surface, harder with cast iron and more harder with steel .
Brass cylinders and plunger no O-rings or with O-rings are not suitable for too high pressure in cylinders with high compression ratio (18-1 or higher) and injection time around 22 before TDC. That's why I use cast iron or steel for the cylinder.
But with moderate pressure - enough to inject well into the cylinder at about 45 degrees before TDC in high compression engine it should be fine. That's why Find Hensen chooses a 45 - 50 degree inject time before TDC for him engine

 

[pirmin kogleck]

okay guys !

i had succes with my Pump configuration , i used some tiny o rings and now my pump is 100% tight and sealed ! no leaks! pump domension is 18mm plunger, 2mm mm bore , 4 o rings like a ringed piston. thats it for now

here a video of the injecotr at full pump pressure

https://www.youtube.com/shorts/iPQbB8iS3xs
i have no idea how much BAR my pump delivers but it should be okay now !

i also machined the flyball governor for the engine build already becaue i was bored and have to wait for my material to arrive

 

[pirmin kogleck]

Here the flyball governors for the diesel build!

One will be for sale i made it extra but have no need for it ! If someone is interested pls send me a message .

 

[minh-thanh]

The way it inject looks fine, but it seems to inject the way it does when there's a sudden high pressure , I not sure
Have you checked the tightness of the injectors ?
The tightness of the injector is really important !!! (I told you about this on facebook group and I also spoke on this forum) If the injector is not completely sealed then you cannot control the injection time, affect the pressure in the cylinder. engine and oil pressure in the oil pipe - Don't expect it to be more tightness with the high pressure in the engine cylinders.
Simply connect your injector ( at the injector inlet or outlet ) with compressed air with a pressure of about 2 - 3 bar and immerse the injector in kerosene ( if using water to test, you should clean it after checking ) no air coming out at the other end it is ok .

 

[pirmin kogleck]

okay guys , small progress here.
since i have to wait for some material and a bit more money for a Mig welder i decided to make all the small parts for the engine one after another , so far i have the governer, the pump and injectors ,

last item is the Sight feed Oilers


check it out

 

[minh-thanh]

pirmin kogleck !

..i am sometimes very very picky and if something doesnt work i cant go to bed without fixing it

I like the way you try to solve the problem.
But , sometimes do something else ..... to clear your mind , and then come back to solve the problem , it will be better .
Anyway, the parts you made are really nice !

 

[pirmin kogleck]

Thank you ! i am very proud on the parts i make, you must know i started machining 6 months ago, i had Zero knowledge about machining metal parts or anyx machine ( i am a cook ) but to be honest, it is a big challenge to copy Find hansens engines if u want to "replicate the engines " since i have no measurements and plans , i have to use his pictures and videos only and sometimes it takes many many hours to make a drawing, check the video again, check the measurements and then check the proportions....now some people would say i am disrespectfull when i replicate an engine from Find but in fact it is Respect.here in ASustria we have a saying : "Imitation is the sincerest form of recognition"

 

[Peter Twissell]

I completely agree!
All of us building engines today are using the knowledge gained by others who built engines over the last century and more.
We are all standing on the shoulders of giants.
I am sure that if our predecessors could see what we are doing, they would be happy to know that their work continues to inspire thousands of home engine builders.