TJI

Why is this not used at all? TJI -Turbulent Jet Ignition, as used in F1 and now in Stellantis New Hurricane 4 engine..

Its supposed to be very complex but it is most likely not when you don't have to care about emissions...Especially when you check out what these guys have done... https://pulse-jetignition.co.uk/shop These guys have used it on motorcycles and cars (Porsche flat six etc) and planes long before F1 did.

Its a cap/cone below a revised smaller spark plug with holes in the cone end of the cap. On ignition, pressure in this pre chamber, shoots jets of ignited charge out through the holes. It gives a much faster and more efficient combustion event, because everything in the combustion chamber is ignited faster.

Tuning with ignition, fueling as well and filddeling with mechanics is a downside... A faster and stronger combustion process is the result. This type is a Passive TJI and will not work as much in lean situations, as is focus now in the industry, but what do we care, stoiciometric operation is more than good enough....

Pro's:

Flame front propagation is much faster so combustion goes faster and cleaner

Cylinder pressure is higher and comes earlier which will ensure

your car will not be as knock limited with you current compression, it can therefore be increased

Lowered EGT

Increased power and torque

Cons:

Of course a stronger, faster and earlier combustion pressure wiĺl put its toll on pistions, rods, bearings and crank, especially the crank torsional damper on the pulley will have to be upgraded.

Quotes:

"Combustion comparison shows that TJI can effectively shorten the ignition delay period and combustion duration. Especially under lean conditions with an excess air ratio (λ) being 1.3, TJI can shorten the combustion duration by 45 % compared with SI"

TJI replaces the spark plug with a jet ignition chamber. During the compression stroke, around 97 percent of the fuel charge is injected directly into the cylinder and the remaining three percent of fuel is directed into the chamber where a traditional spark plug ignites that small, overly rich charge within the tiny confines of the chamber. The resulting high-pressure jet stream of hot gasses are forced through a number of tiny holes in the chamber and into the main cylinder to ignite the rest of the air-fuel charge, which is by now thoroughly mixed and lean. According to Mahle, these hot jets fire out to the edge of the piston to ignite the mixture."

Well it is and it isn't the old pre-chamber. The best you can say is that it's based upon the old pre-chamber.It's using a chamber in the spark plug rather than the head, but the injection is different and the burn pattern(s) is WAY different

"The Turbulent Jet Ignition concept involves the use of a chemically active, turbulent jet to iinitiate combustion in lean fuel mixtures. With jet ignition, the combustion of the main charge is reliable over a much broader range of air-fuel ratios since the jet acts as a distributed ignition source. The large number of distributed ignition sites ensures that the flame travel distances are relatively small enabling short combustion durations even in traditionally slow burning lean mixture

Quotes end:An engine is an air pump, but it is also a slave of combustion efficiency, the primary artifact in all engines, is combustion. For the same air delivery, better combustion efficiency, is only better. TJI makes the combustion faster, because the speed of the flame front propagation is much faster. Thereby the name Pulse jet or Turbulent jet ignition. So in principle it makes the charge inside the combustion chamber ignite much faster, so that those "poor" air and fuel molecules out by the cylinder wall don't get left alone, and then self ignite, or knock. Which we all hate...

This is truly an invention that should not have come 50 years to late, because it is, a genuine way to improve combustion efficiency. Nowadays its drawn into shambles of emissions. So F1 finally made it mainstream because some dude there, picked up the idea, it was NOT his, it was already known!!!! It had been dabbled about for a long time before, by the link I mentioned to https://pulse-jetignition.co.uk/shop and also Honda in the 80's etc etc.

And I suspect it's still valid, it will work on any engine, but the research and experience about this tech, for your engine, has not been developed through the years.

So maybe its just a lost cause?