The key benefit of HCCI is rapid combustion with completion very close to TDC.PlatinumZealot wrote: ↑03 Oct 2017, 08:13Nope still slower. Even if HCCI ignites the whole the mixture at near the same Instant... You still have to wait to build up enough peak pressure to ignite in the first place. Just like deisel Poor or no control over ignition timing.ncassi22 wrote: ↑02 Oct 2017, 00:20HCCI ignition is quicker than SI. Would the issue not be a control and excessive cylinder pressure issue? Ultra lean Lean HCCI can be assisted by TJI/CVCC to ignite reliably (Forced into HCCI mode). Nice thing about these MGU-H assisted turbos, are that you can get high boost pressures at lower RPM and load - maybe do psuedo HCCI in these lower reaches to increase economy.PlatinumZealot wrote: ↑01 Oct 2017, 15:20The way HCCI works it is not suitable for F1 engines at high rpms... Hcci is compression ignition which is too slow for f1.
TJI is what we know is used in Ferrari Mercedes and Renault. Honda is yet to be confirmed but it was alluded to by hasegawa that the engine has all the
" lastest" technologies.
Racing engines have similar port velocities regardless of rpm and boost. The port cross section area is sized to achieve the desired velocity.ncassi22 wrote: ↑03 Oct 2017, 17:45Also I'd assume with 4 -5 bar of boost and 12000rpm port velocity must be pretty high too; with dimples wayyy too small to have any effect as the dimpled surface would just stall and act as a smooth surface anyway.MrPotatoHead wrote: ↑03 Oct 2017, 14:14These days a little smoother is desired - but not too smooth. There is a sweet spot of around 10 to 20 microns cusp height on a cnc ported head that performs the best. This seems to produce a boundary layer that is about perfect.
Aren't the engine direct injection? Where would fuel puddle? It's going directly into the cylinders......rough finish is not for aerodynamics. But to prevent fuel from puddling on the walls. The V10 engines were showered in fuel from those port injectors so i assume that you want to prevent any coallescing which would happen on a smooth surface..
On the piston crowns and cylinder walls which contributes to wall quenching, and is unavoidable, although you can mitigate it to a certain extent by doing things with the head, chamber and piston crown itself. And obviously the injectors.Rodak wrote: ↑04 Oct 2017, 03:07My first post here, so please be gentle. @ PlatinumZealot:Aren't the engine direct injection? Where would fuel puddle? It's going directly into the cylinders......rough finish is not for aerodynamics. But to prevent fuel from puddling on the walls. The V10 engines were showered in fuel from those port injectors so i assume that you want to prevent any coallescing which would happen on a smooth surface..
https://www.autosport.com/f1/news/13219 ... de-dilemma"If there is a new spec engine or any improvements, that will be with a penalty and we will start last.
"So it is difficult to compensate if we want to start last with an extra horsepower, or do we want to do a perfect weekend and try to score points?
"It is not up to us. The Honda engineers will tell us if first if there is an evolution ready that we don't know yet and if there is something ready, if it is better to take that opportunity or not."
Usually the higher scoring driver gets the update. Who's going to tell Alonso?loner wrote: ↑04 Oct 2017, 17:01https://www.autosport.com/f1/news/13219 ... de-dilemma"If there is a new spec engine or any improvements, that will be with a penalty and we will start last.
"So it is difficult to compensate if we want to start last with an extra horsepower, or do we want to do a perfect weekend and try to score points?
"It is not up to us. The Honda engineers will tell us if first if there is an evolution ready that we don't know yet and if there is something ready, if it is better to take that opportunity or not."
we will know in the coming 24 hours hopefully Fabrega source is very reliable and here will be one unit available.
i assume no more new spec 3.7 it was just a stop gap til they have the spec 4
7 august aricleIt's hoped 'Spec 4', which is expected to debut at the Japanese Grand Prix, will deliver another major boost, taking Honda past Renault, according to motorsport chief Yusuke Hasegawa.
"I think we can keep the same ratio of the increasing of the power but it is difficult to catch up Mercedes or Ferrari," Hasegawa told Motorsport.
"I really want to move ahead of Renault in terms of performance before the end of the season."
Asked if that was a realistic goal, given Honda's woes, Hasegawa hinted that data from their 'Spec 4' power unit showed positive gains.
"Yes," he replied. "I can see that on the data. I will not tell you the number, but we are closing the gap [to Renault]."
Hence the massive vibration issues. The sound of this engines can be misleading because of the way the turbo is used ( MGUH and so on).