Passive prechamber spark plug (DIY??)

[pgfpro]

This is a company that is in my area.
SmartPlugs - About

They have been producing these for the military to run all types of fuel. It requires a high compression engine because its also an ignition system. They have been retrofitted to all types of engines. They work very well, I have seen them tested first hand. They have several patents to protect themselves but it's some good info to come up with your own.

[serialk11r]

@teoman I don't think that's possible, you can't place multiple ignition points far away and have the arc jump to them (the arc would just go to the valves instead which are closer). Building a consumable item into the piston is not a good idea anyways. If you had a 3 valves per cylinder, you could put two spark plugs to either side of the single exhaust valve. Along similar lines here is the Miyama Multispark concept placing ignition points where the head gasket is: Miyama MULTIspark | Multi-point ignition technology

@pgfpro Catalytic autoignition sounds like a really bad idea to me. You have no control over when it ignites. Since you need to wait for gas to diffuse through the chamber, you're losing ignition timing as speed goes up, which is not good.

[teoman]

I knew if it were a bright idea it would have been already implemented.

[pgfpro]

Originally Posted by serialk11r

@teoman I don't think that's possible, you can't place multiple ignition points far away and have the arc jump to them (the arc would just go to the valves instead which are closer). Building a consumable item into the piston is not a good idea anyways. If you had a 3 valves per cylinder, you could put two spark plugs to either side of the single exhaust valve. Along similar lines here is the Miyama Multispark concept placing ignition points where the head gasket is: Miyama MULTIspark | Multi-point ignition technology

@pgfpro Catalytic autoignition sounds like a really bad idea to me. You have no control over when it ignites. Since you need to wait for gas to diffuse through the chamber, you're losing ignition timing as speed goes up, which is not good.

They actually dyno all the engines before and after to determine a base line power and what element will be used to make improvements. They increase the compression ratio with a much higher comp piston. Also with their pre-chamber modification it won't need a lot of ignition advance because of the flame jet it produces vs a conventional kernel. The flame speed increases drastically. So this is why it works amazing for a lean burn engine. The dyno results show an increase in HP and torque across the power band.

[serialk11r]

Originally Posted by pgfpro

They actually dyno all the engines before and after to determine a base line power and what element will be used to make improvements. They increase the compression ratio with a much higher comp piston. Also with their pre-chamber modification it won't need a lot of ignition advance because of the flame jet it produces vs a conventional kernel. The flame speed increases drastically. So this is why it works amazing for a lean burn engine. The dyno results show an increase in HP and torque across the power band.

MAP will also affect the timing too, it's just too many variables that aren't being controlled for my liking. Can you buy them anywhere? It would be fun to test on a gas generator or something.

Another thought, with less ignition advance and higher compression ratio, the benefit of an offset crankshaft increases, since there's less stress on the piston on the compression stroke. A nice candidate to test a prechamber plug on would be a Toyota AR engine.

[serialk11r]

Here's another video from another company trying to do this for passenger cars. They have change in BSFC graphs:
https://youtu.be/PCDDXtFmtVs?t=135

The active prechamber is good for increasing EGR dilution which explains the large low speed low load gains, while the passive prechamber is only good at increasing combustion speed (you see a small ~2% improvement at low load low speed, while it goes up to 4% by 4000rpm, and I imagine the gains would be even more impressive at say 7000rpm). On a car with a smaller engine that operates at a higher mean load, the passive prechamber would still yield some pretty good gains combined with increased compression ratio.

[pgfpro]

Originally Posted by serialk11r

MAP will also affect the timing too, it's just too many variables that aren't being controlled for my liking. Can you buy them anywhere? It would be fun to test on a gas generator or something.

Another thought, with less ignition advance and higher compression ratio, the benefit of an offset crankshaft increases, since there's less stress on the piston on the compression stroke. A nice candidate to test a prechamber plug on would be a Toyota AR engine.

I'm like you and would want to be able to control ignition maps.

I will look into seeing if they will sell them in a couple weeks.

The AR engine would be an excellent choice for a test engine.