Where does the "spin" originate?

A diesel engine requires a "swirl" for proper combustion.
Where and how exactly is the spin generated?
Is it not possible to widen the channels in a simple way?
Does the spin get lost?
How about larger valves?

best regards
Torsten.

hello

'It's not just the diesel engine that needs swirl, but swirl is often a combination of swirl and tumble, which is then called 'tipped'. The way these movements are created depends on the type of injection: direct, pre-chamber, or swirl chamber. Furthermore, it depends on the valves, the position of the valves, and the intake manifold. If you want to make any changes, it's best to do so on a flow bench.'

I hope I've helped you.

peter

Hello Peter,

Thank you very much for your reply.
First of all, I want to mention that my car is a TDI, which means it's a direct injection diesel engine. Is the airflow behavior comparable to that of a gasoline engine?
Following the motto: What is good for a gasoline engine, cannot be bad for a diesel engine.
Does the "classic tuning" typically applied to gasoline engines also work with diesel engines?
What if I polish the valve guides and the valve seats?
What needs to be considered?
Unfortunately, as a private individual, I do not have access to a wind tunnel.

Sincerely,
Torsten.

Without further modifications, polishing alone won't achieve much because while it might allow for slightly more air, it will also let in the same amount of diesel into the cylinders. For a TDI engine, the first step is usually a chip tuning or power box, followed by larger injectors and a turbocharger.
For a naturally aspirated gasoline engine, things are naturally different.

@ Corry (as an explanation regarding Christians)

Here, the saying "What's good for a gasoline engine..." does NOT apply.

The gasoline engine sucks in the air-fuel mixture. So, if you can increase the volume of air flowing through by widening and polishing the channels, more of the mixture will enter the cylinder, resulting in a bigger "bang" and thus more power.

With a diesel engine, you are only introducing more __air__ into the cylinder - of which there is already "too much," because diesel engines always operate with an __excess__ of air.

A 1Z engine (90 HP TDI in a Golf3) can have up to 20% more air in the cylinder than it needs for the standard fuel injection amount (required for clean combustion).

That means you can burn almost 20% more diesel without producing soot, all without making any mechanical changes. That's exactly what a "10 Ct. Tuning" or a simple power box does (by simply injecting more diesel). Only after you've already used up this "gift" of excess air do you need to add more air. But even then, hardly anyone will polish the intake channels; that's what the turbo is for. So, by using a chip (or even a "10 Ct. Tuning"), increase the boost pressure and inject even more diesel.

m;

Thank you for the detailed explanation.
I think I understand.
Currently, I only offer performance enhancements for gasoline engines.

t.

Here's another beautiful picture showing what polished channels can achieve in a TDI engine that has been running for a long time (after 180,000 km):
http://www.luxus-wg.de/~martin/auto_bilder/AGR_Saugstutzen/Kopf_3-2.jpg

Well, there's nothing polished here - but if there were, no one would notice it anyway.

The AGR (Abgasrückführung) and oil mist in the intake manifold create a "bake-bake-cake" situation.

http://www.luxus-wg.de/~martin/auto_bilder/AGR_Saugstutzen/
http://www.luxus-wg.de/~martin/auto_bilder/AGR_Saugstutzen_sauber/
http://www.luxus-wg.de/~martin/auto_bilder/Kruemmer/

Hello,
That looks really dirty and grimy.
After the cleaning, it was very clean, and could you notice a difference in how it ran?
Where does the dirt come from?
KW-Ventilation + EGR?

t.

The dirt is coming from the cooling system vent, but also likely from a slightly leaky turbo, and then there's the soot from the EGR valve.

I didn't immediately notice any differences in the driving experience, probably because I changed several things at once and hadn't driven for a while.

m;: