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Algae biodiesel is a funky topic, I know of some researchers in that area who are trying to make algae whose photosynthesis is *less* efficient at absorbing light. The reason being that the algae easily block light from all but the top of the tank, so algae lower down die! Apparently stirring...

Partly. A precombustion chamber engine is also much easier to design than a direct injection one, I didn't have to worry about things like swirl ratios in the cylinder or the exact piston bowl geometry, just a spherical pre-chamber in the head and a passageway of appropriate size to connect it...

My design is very similar. The only issue is that the spray cone is quite narrow, so it suits some combustion chamber designs but not others.

Have you considered the MAN M-system design? It quite deliberately doesn't atomise most of the fuel, instead the fuel is squirted onto the surface of the piston bowl and intense air swirl strips layers of vapourising fuel from the resulting film. This is the method that was used in the...

I think it's some sort of very soft aluminium, sort of like a very thick foil or maybe shim stock. Easy to bend into shape, I was able to cut out a circle and draw the ID of the hole downwards, then sort of wrap it around the inside of the paper gasket. Result wasn't too great but I feel with...

Today I did the sanding thing on both block and head. Didn't help in the slightest! Thankfully, I think what I did next has revealed the source of the trouble. I decided to try making a soft gasket, so I cut one out of a manila folder. This gasket produced stronger compression, but upon testing...

Today I blued up my scraping master and checked the head and block top. The head isn't too bad for a milled part, but the top of the liner has two low spots that correspond pretty closely to where I've been having leaks. Also there's no contact on the prechamber cup, so it could be forming...

I'll give it a check with some engineers blue.

That's real pretty, excellent machine work!

Silver steel is water hardening tool steel typically made to BS 1407 and supplied normalised and centerless ground.

Indeed, I have in the past done this sort of thing by putting wet and dry sandpaper on the surface plate.

As flat as I could get them given how well my mill was machined at the factory (the spindle tram cannot be changed without scraping). The surface finish is not ideal because I fed a bit fast when milling. There's scope to lap or scrape them in (and with scraping I could probably get a seal with...

Yes, 0.6mm, not without making a dummy injector to adapt my compression tester to the cylinder head (I also need to check if the gauge goes high enough). The compression is certainly high enough to ignite starter fluid (it ran on it) and burn oil (I can smell it even cranking without fuel).

Thanks, I like this design. I ordered some fiber reinforced graphite material from eBay already, do you think it would need the metal fire rings? I also thought I might try forming fire rings from shim stock and wrapping them around the soft gasket material.

I did consider this, but the head is pretty cramped, the only space available is between the inlet and exhaust ports which is very narrow. I'm confident there was no hydrolock, in fact when I removed the head afterwards it was fairly dry with only a thin film of fuel/oil. The injector not...

Last couple of days I made up some mounting brackets, fuel fittings, crush washers and so forth. Timed the injection pump. Broke the high pressure line to the injector and had to braze on a new one. The engine is now complete enough to begin testing for fuel injection system issues, I'm planning...

Makes sense. I do worry about the stress riser from the step given the heavy loads in a diesel, but your pin is pretty big so it will probably be ok. 316 and 304 do turn beautifully, except for the stringy swarf! Not so nice to drill however. I make my gudgeon pins from silver steel.

Why the stepped gudgeon pin?

The ideal with HCCI is to have a cool, lean burn. Lean burn like a diesel is ideal for fuel economy, but the combustion of a diesel is very hot around the fuel droplets hence excessive NOx emissions, and also the burn conditions can be rich in some areas of the cylinder at high loads (= black...

4000 psi is a fair bit more injection pressure than we are running, I think. At least I'm aiming for 100 bar, about 1500 psi. I'm fairly sure that I've read that the lower pressure reduces 'penetration' of the spray. So presumably our sprays don't go so far. Nevertheless, what we see in that...