My new project ...Diesel engine .

[AlexS]

me too! sounds good!

[AlexS]

The projects is interesting to follow. I have no pratical experience with diesel engine other than visit to test plant of DAF truck engine departement and VW. Which was interesting to see!

But also Roger progress and builds are interesting to follow. To realize a system for our homemade creations.

Out of the box, after deep chat with copilot maybe give a ball park idea to downscale a simple injector and delivery pump and spill port for variable quantity?. Maybe it is good idea to build a IDI indirect swirl chamber instead of DI direct. But still need high pressure at nozzle opening and pumping. Which need accurate tolerances and machining. Might interesting to outsourch critical parts far east in the world.

Might be interesting to first design and run the engine om gasoline and keep in mind to later turn to diesel. Building an Direct or indirect gasoline injection system which is less critical and prove the design. Later swapping piston/cylinder head to high compression. Gasoline is thinner and mix better with air, lower injection pressure needed and need less critical injector and pump body/piston!

Sorry I don't want to rush but this idea was in the head of couple days!

Greets

[Minh Thanh]

Sorry I don't want to rush but this idea was in the head of couple days!

Greets

Why the "sorry" !!??   Let's discuss this so everyone, including myself, understands better 

The pump doesn't need to create high pressure; the fuel injection time can be at 50 degrees before TDC, at which point the pressure in the cylinder is low.

[AlexS]

Great!

Okay I don't know exact delay or ramp angle when the cam lobe hit the maximum lift and the full open duration when there actually the needle of injector opend. What I read that aiming at 150 bar opening pressure of nozzle with very small holes (0.2-0.3mm two or more). But indeed cylinder compression pressure is far less. I could imagine that diesel is difficult to evaluate or create larger droplets under lower injection pressure. Which for model engine it would less a issue than modern emission targets. Maybe 80 bar would also be safer.

Well it would interesting to see one homemade!

[Minh Thanh]

  Hi AlexS !
For valve-type nozzles: I don't know the actual injection time.

Injection time: When the lobe begins contacting the plunger.

Lobe: After some testing, I found that straight lobes seem to inject slightly better than lobes with a curved radius.
Nozzle with very small holes (0.2-0.3mm, two or more): I haven't tried it, so I don't know. But I probably won't try it; I'll choose a simpler diameter that's feasible, inexpensive, fast... and still achieves the same result: the engine runs.

[AlexS]

Thanks for information! It is for sure a archievement that engine runs;)

[Minh Thanh]

 Hi All !
An update

[CI]

 

[vtsteam]

I don't know much about diesel engines, but the base is a beauty. How did you make it? 

[Minh Thanh]

CI , Steve . Thank you !
 A diesel engine is similar to other internal combustion engines, the only difference is that it has a higher compression ratio and fuel injectors and a fuel pump.

 

. How did you make it? 

 
  I haven't finished it yet because there are still a few holes to drill...
Here are a few pictures, hopefully they're helpful.
Just marking for sawing, milling, grinding, and a little bit of finesse.

It was made using a milling machine converted from a drill, and with a homemade l...a...t...h...e - you could call it a lathe - grinding... all of it.

[vtsteam]

Wonderful! 

I don't want to sidetrack this thread, but is there somewhere else where I can see or read about your lathe and converted drill/mill?

[Minh Thanh]

Wonderful! 

I don't want to sidetrack this thread, but is there somewhere else where I can see or read about your lathe and converted drill/mill?

Hi !
Machinery and tools are part of the machining process.

The lathe I built over 12 years ago, just a few simple things and it was a  "lathe !?".

But what's very interesting is that I built engines: Stirling, flame eater, steam, 2-stroke, 4-stroke - up to V4 and I4, and including "true" diesel engines (pump and injectors) and even an I4 true diesel engine from that lathe.

As for the milling machine: I just made the X-Y axis and assembled it onto the base of a bench drill, and it became a milling machine.
 
I'm planning to change a few things to make them better and upgrade them into an NC machine... Perhaps at some point in the future....

I recently bought a Chinese lathe (around 600 USD), which makes machining easier. However, perhaps due to habit, I usually use my homemade lathe, while the Chinese lathe, after adjustment..., I use it for tasks that sometimes require precision, such as turning long shafts or needle turning....

 some pictures for you.

[CI]

Nice work !
.

[Roger B]

A nicely made lathe    You get good results from it 

[Kim]

Wow! That's quite amazing! 

Kim