Mini diesel engine.

[minh-thanh]

Thanks All !
About the plan:
Give me little time
With a lot of trial and error, change - change, adjust and ..... adjust... valve, injector, pump..and make new pistons, rings and cylinder heads
With a lot of test runs I have to check if pump and injector are good enough for long run time.. and I think it is enough for my requirements.

So much so , yesterday , there was an adjustment where the engine runs at its best and I no longer have the patience to adjust the engine again .
The video above is not the best way to run the engine but I think it's okay for you to watch
This engine seems to take all my patience !
I will try to finish it soon

 

[Mechanicboy]

Thanks All !
About the plan:
Give me little time
With a lot of trial and error, change - change, adjust and ..... adjust... valve, injector, pump..and make new pistons, rings

Add piston oil ring to keep oil in the crankcase since we are spotted your engine is spitting the oil out of exhaust pipe and too much smoke. Maybe you can smell there is unburned oil smoke. It's not good for the engine. The main function of the oil ring is to scrape any excess oil from the walls of the cylinder liner when the piston is in motion. The majority of the wiped oil is directed into the crankcase back to the oil sump.

 

[minh-thanh]

Please review my previous 2 videos
And I said the last video is not the one where the engine runs the best !
You said : " WE " ??

 

[djswain1]

Hi All !
An update:
I have conquered a real challenge : Diesel engine 10 cc .View attachment 131273View attachment 131274View attachment 131275




Thanks everyone !

Excellent work Minh-Thanh

 

[Thommo]

Thanks All !
About the plan:
Give me little time
With a lot of trial and error, change - change, adjust and ..... adjust... valve, injector, pump..and make new pistons, rings and cylinder heads
With a lot of test runs I have to check if pump and injector are good enough for long run time.. and I think it is enough for my requirements.

So much so , yesterday , there was an adjustment where the engine runs at its best and I no longer have the patience to adjust the engine again .
The video above is not the best way to run the engine but I think it's okay for you to watch
This engine seems to take all my patience !
I will try to finish it soon

Hey Than, I’m impressed with that little diesel! You showed a lot of courage and confidence building. Not may guys, even very experienced builders are willing to tackle a diesel. Well done!

 

[kuhncw]

Very well done, Minh Thanh. Your engine looks very nice and runs well. A diesel is a real accomplishment.

Chuck

 

[minh-thanh]

Hi All !
A update :
I just redrawn my diesel engine
I will check the plan again, hope everything is ok
Hopefully in a few days there will be drawing .

 

[minh-thanh]

Hi All !

Ser at this engine how to set timing..
Sorry I wrote wrong about 40-45 degrees before TDC at Find Hansen's engine, should be between 45 and 55 degrees before TDC. His diesel engine is set at 45 degrees before TDC can set up to 55 degrees, but the lever with excenter at the fuel pump (see at the movie) can be adjusted 15 degrees in the area where it runs best without getting an ignition knock. So you have to try out how big the angle is before TDC it goes best and easy to start up without ether in fuel and heating of the cylinder head.

I forgot one important thing :
When I change the compression ratio (higher) and change fuel (using kerosene), I have to set the injection start to about 45 (maybe more) before TDC.
I'm wrong
I owe Find Hansen and Mechanicboy an apology !
I'm sorry

 

[Mechanicboy]

Hi All !



I forgot one important thing :
When I change the compression ratio (higher) and change fuel (using kerosene), I have to set the injection start to about 45 (maybe more) before TDC.
I'm wrong
I owe Find Hansen and Mechanicboy an apology !
I'm sorry

Minh-Thanh..
You are forgiven.

From the time atomized paraffin leaves the injection nozzle until the paraffin begins to burn is called ignition lagg. This is why we set the injection time much earlier so that it takes time to heat up the atomized paraffin from heat of compression until it starts to burn a few degrees before TDC. Temperature development in a small diesel engine is not as great as large diesel engines that can have compression temperatures up to 550-600 degrees and then the injection timing will be much shorter around 10-20 degrees before TDC depending on engine design. Ignition lagg is shorter than in the model diesel engine due higher compression temperature in large diesel engine.

 

[minh-thanh]

Mechanicboy !

When I change the compression ratio (higher) and change fuel (using kerosene)

Like I said, it only happens when I increase the compression ratio and use kerosene
With less compression ratio, I set the injection time to about 20 degrees before TDC, using a mixture of ether + kerosene + oil w and using only kerosene

 

[minh-thanh]

Hi All !
Sorry for replying so late
I have to do some work and edit the plan
Now the plan is done
Price: 30 usd
Paypal account: [email protected]
I'm not a professional engine designer, let me know if I'm missing something or something you don't understand
If you have any questions, please email: [email protected]

 

[awake]

Hi All !
Sorry for replying so late
I have to do some work and edit the plan
Now the plan is done
Price: 30 usd
Paypal account: [email protected]
I'm not a professional engine designer, let me know if I'm missing something or something you don't understand
If you have any questions, please email: [email protected]

Paypal sent, including email address. Looking forward to seeing the plans!

 

[awake]

I received the plans promptly, and they look good! I am looking forward to digging into them in detail. Thanak, Minh-Thanh!

 

[minh-thanh]

Hi Awake !
Thank You very much !
Let's make a diesel engine. And when you make it run you will have many surprises , I SURE !
And then, it's not just one or two people who can do it
And then there will be more diesel engines and more designs....

 

[Chaffe]

Hello, great write up. Do you have any techniques for machining injection pump bore? Also injection pump piston itself? Some sort of lapping perhaps? What sort of tolerances are acceptable here?
I have a similar project in progress but currently use tiny nitrile O rings for seals, not ideal.

 

[Chaffe]

It has been an ongoing project for a couple years, with many interruptions

 

[Chaffe]

Here in action with 100% kerosene, injection pressure is very low at 8 bar, this is something I am working on

 

[minh-thanh]

Hi Chaffe !

With me : drill - reamer - lapping
Small hole lapping tool : you can buy it or make it yourself - I made it myself

https://www.mcmaster.com/lapping-tools/
Lapping pump cylinders is challenging and very patient
All scratches caused by drilling or reaming must be removed
Tolerance : I think it's about 0.01 -> 0.02 mm - I'm not sure - Because it's too small
I used o - ring - just for testing . They fail quickly with high pressure .This only improves when the cylinder surface is very smooth. I don't know if it will last long, but I don't like it to fail when I'm testing as well as I want the engine to run for a long time.
Piston: I make the piston diameter 0.1 - > 0.3 mm larger than the cylinder (this depends on the surface when machined), then lapping the piston until the piston slides into the cylinder with w20 oil
Cylinder and piston surfaces must be smooth

 

[Chaffe]

Thanks, my next plan was exactly as you describe, using cast iron for cylinder and silver steel as piston, a split aluminium lap.
but first I must finish my Stuart steam engine…

 

[minh-thanh]

I also use brass for the cylinder , they're pretty good