Excuse the annoying accent on the commentator but watch this video.
Basically changing the spark plug hole shape can reduce EGTs by 600 F!
One thing I\'m not convinced on though is the spark plugs causing pushing forces in opposite directions in the engine as he doesn\'t explain that the sparks actually fire at different times, and that the trailing spark plug is there to ignite excess fuel/ better complete combustion.
Anyway here\'s the video so you know what I\'m talking about
http://youtu.be/m3pCLjHZmhM
He\'s not talking about the firing process grant, what he\'s saying is true that at tdc with the compression bowl central e compression force is equal and only momentum carries it over the top.
Interesting ideas though.
Surely though the split timing will reduce this? The lemans car had 3 plugs per rotor so I\'m sure that is t much of an issue, however I do think the offset bowl is a good idea
Did you notice his Plugs had moved on his modified housings. I think the trailing plug is more to do with complete burn as the bowl is so long as a posed to a :censored::censored::censored::censored:ed on motor.
I think it may cause balance issues at higher rpm but interesting ideas, I also wonder how effective the spark is with a small slot rather than a large hole.
Yeh the trailing plug is for better burn, you can run the engine without those plugs if you want.
Yeh I noticed the plugs holes were both on the bottom side of the lobe in the housing. That\'s a strange one but must have done that to work with the offset bowl? Hmm.
If the spark is strong enough and the slot has the same area as the conventional hole then it should work as good, then you wouldn\'t get the blow by he is talking about.
Reduced EGTs by 600F is a lot, should put it back too similar levels of a piston motor
I was guessing to match the bowl as well.
It\'s not just area it\'s locality to the spark, I wonder why Mazda used such a large hole in the first place.
Reduced egts are a good thing but it would hurt turbo spool?
I want to see more, like a running prototype.
Me too, from what I understand higher egts give great velocity which helps spool turbos? I may be wrong, however the amount of air flow through a rotary is tremendous so we should still be able to spool big turbos even if the egts went down. Plus overlap helps spool turbos, raw fuel and air going out of the exhaust, same as the large spark plug hole I guess.
See the things that make rotors grate are also their biggest downfall.
Not necessarily, standard ports and huge boost can still make good power.
Don\'t forget though that a rotary sounds best when it braps. Overlap :D
Hes barking up the wrong tree cos even though spark is often before tdc the actual dynamic phase of pushing the rotor around takes place long after the rotor has moved past tdc as the pressure wave begins to rise and is at max way beyond tdc where combustion chamber dont really matter anymore.
Piston engines are the same with at various times spark taking place before tdc when piston is still rising in opposite direction to what eventually becomes the power phase.
People forget that the expansion phase is a controlled burn over time and not just a big instant explosion.
I was wondering about that primary spark plug hole too. Because secondary spark plug hole is small... That 16x engine prototype, does it have 3 spark plugs?
Quote from: HaywardRotary;847961Hes barking up the wrong tree cos even though spark is often before tdc the actual dynamic phase of pushing the rotor around takes place long after the rotor has moved past tdc as the pressure wave begins to rise and is at max way beyond tdc where combustion chamber dont really matter anymore.
Piston engines are the same with at various times spark taking place before tdc when piston is still rising in opposite direction to what eventually becomes the power phase.
People forget that the expansion phase is a controlled burn over time and not just a big instant explosion.
That is what I was thinking Carl when the mixture ignites it is more of a controlled burn than an explosion, pushing the rotor around.
It would be good to see if the different sized plug holes made a difference in the EGTs, although would lower EGTs actually gain any better other than cooler engine and its parts. More importantly cooler rotors and apex seal, also maybe burning less oil withing the engine?
Quote from: re japi;847964I was wondering about that primary spark plug hole too. Because secondary spark plug hole is small... That 16x engine prototype, does it have 3 spark plugs?
IDK but they were talking of using laser ignition for better burn of the fuel and lower emissions.