Maseratti Nettuno pre-chamber engine

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
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Holm86
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Re: Maseratti Nettuno pre-chamber engine

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Bence wrote:
Sat Jul 11, 2020 1:18 am
Holm86 wrote:
Wed Jul 08, 2020 10:10 am
But I don't think a 90° V6 will ever sound that good, it also has a firing order of 1-6-3-4-2-5
...C30/32-powered NSXs were sounding goosebumpily good...
Yeah it's a matter of personal taste, but I never liked the sound of those ...

gruntguru
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Re: Maseratti Nettuno pre-chamber engine

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Found this quote from an earlier paper on TJI. It explains the benefit of the extra spark plug external to the pre-chamber.
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Additionally, a new concept in “Spark Assisted Jet Ignition” combustion was proposed to enable stoichiometric boosted high load operation, where the jet igniter is coupled with a conventional spark plug. With this concept, some of the main chamber charge is consumed first using the conventional spark ignition flame propagation process, with the remaining charge consumed by the jet ignition process Figure 14. Two possible configurations for “Spark Assisted Jet Ignition”, where some of the main chamber charge is consumed using the conventional spark ignition flame propagation process and the remainder using jet ignition combustion in order to increase the burn duration and reduce the heat release at stoichiometric boosted high loads.
A Gasoline Fueled Pre-Chamber Jet Ignition Combustion System at Unthrottled Conditions
Attard et al / SAE Int. J. Engines / Volume 5, Issue 2(May 2012) 327
je suis charlie

63l8qrrfy6
63l8qrrfy6
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Re: Maseratti Nettuno pre-chamber engine

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Why would one want to increase burn duration and reduce heat release?

gruntguru
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Re: Maseratti Nettuno pre-chamber engine

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I think TJI equipped engines can get into excessive pressure rise rate trouble (with consequent noise and harshness) under some conditions.
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63l8qrrfy6
63l8qrrfy6
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Re: Maseratti Nettuno pre-chamber engine

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Engine designers have been chasing that ideal instantaneos heat release at constant volume for so long it almost feels like blasphemy having to actively reduce the heat release rate. I do get the point that the closer they get to ideal, the sharper the rate of pressure rise and the higher the peak pressures.

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etusch
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Re: Maseratti Nettuno pre-chamber engine

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It looks like they didn't work on combustion process which is most expensive part of engine to develop. Usage of two spark plugs, two injectors, it looks like it is some kind of feature useless in real world but made to put it as item to count in the car catalog.
There may be a difference between F1 engine which is idling at higher revs and a road engine revs lower rpms. But I think they could achieve it in that rev level by using compressor/supercharger and higher compression. Mazda uses same concept without prechamber. They worked on it for long time to make it work properly. ( I don't know how long maseratti worked on it ) but looks unsufficient in first look.
At the end if it runs with prechamber with spurk plug in it at higher revs still not bad.
They are talking about efficiency etc in the video but compression ratio is 11:1 while skyactive x has 16.3:1. I don't know but it looks very striaghtforward engine.