Honda Power Unit Hardware & Software

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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Nuvolari
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Re: Honda Power Unit

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Wil992 wrote:
08 May 2017, 12:22
Apologies for a possibly simplistic question.
Regs say only 1 injector, but multiple injections are allowed, is that correct?
If that's the case, then would it not make sense to have the injector in the pre chamber, inject once during intake stroke, to give a relatively lean mixture in main and pre, then a second injection immediately prior to ignition, to give a richer mix in the pre chamber than the main?
Am I missing something? Is there any evidence to tell us where the injector is, or is it all just speculation?
Thanks.
Up to five ignition events (sparks) are permitted per cycle (no limits on injection events), so I imagine fine control over combustion is possible. Looking at Mahle's diagrams:

Image

If the injectors are anything like this in F1, would these pre-chamber nozzles also help in homogenising the combustion chamber for the 'lean' injection, in addition to firing jets during the actual combustion? Also how about simple seperate channels from the same injector for pre-chamber and main chamber injections?

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etusch
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Re: Honda Power Unit

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Can injector has holes like diesel pre-chambers more than one or could it have only one injection point/hole ?
Last edited by etusch on 08 May 2017, 17:00, edited 1 time in total.

hurril
hurril
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Joined: 07 Oct 2014, 13:02

Re: Honda Power Unit

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Nuvolari wrote:
08 May 2017, 16:05
Wil992 wrote:
08 May 2017, 12:22
Apologies for a possibly simplistic question.
Regs say only 1 injector, but multiple injections are allowed, is that correct?
If that's the case, then would it not make sense to have the injector in the pre chamber, inject once during intake stroke, to give a relatively lean mixture in main and pre, then a second injection immediately prior to ignition, to give a richer mix in the pre chamber than the main?
Am I missing something? Is there any evidence to tell us where the injector is, or is it all just speculation?
Thanks.
Up to five ignition events (sparks) are permitted per cycle (no limits on injection events), so I imagine fine control over combustion is possible. Looking at Mahle's diagrams:

http://www.motorsportmagazine.com/wp-co ... /Mahle.jpg

If the injectors are anything like this in F1, would these pre-chamber nozzles also help in homogenising the combustion chamber for the 'lean' injection, in addition to firing jets during the actual combustion? Also how about simple seperate channels from the same injector for pre-chamber and main chamber injections?
See, the problem with this is that in F1, you are only allowed one injector. That solution requires two and hence completely avoids the problem of getting the fatter charge into the pre-chamber, or the brunt of the charge out of it.

GoranF1
GoranF1
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Re: Honda Power Unit

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muramasa
Today, 12:54

 

=========================================
bullets are for Hasegawa quotes as well as Nakamura (where specified so)
=========================================



China


Friday

http://f1sokuho.mopi...no=107558&tt=-1
https://sportiva.shu...__split___f1_3/
https://sportiva.shu...9/f1___split_7/
also print media etc (same for the rest too)


(on "easy" comment reported on autosport etc)
Of course we never thought like it was easy. At the point where we managed to achieve the target on mono-cylinder, we thought it would not be too difficult to proceed the remainder of the development and achieve the comprehensive target at that rate. But when we moved on from mono cylinder to V6, the supposed power was not there, so eventually had no choice but to enter the season with compromised spec.
We managed to achieve our target performance on single cylinder dyno test. There is a certain figure that "if mono cylinder is this much, it should be this much on V6 by calculation", but when we actually made V6, we were not able to get the supposed figure. That's what it was at the end of last year, at which point we already run out of time, so we had no choice but to introduce immature/compromised/interim one first for the season opener.
We are having some solutions that have good prospect, so we hope to introduce them sooner, and we'd actually like to introduce as soon as it is ready, but it's not next race that it will happen.
Perhaps with the first update, recovering to the point where they exceed last year's is all they can do. (anonymous unspecified "team personnel")


During the turmoil (splitting and switching to Merc etc) Honda held talks with McLaren 3 times in Aoyama and Woking and decided to make some modification to structure of Sakura, and it was something that mclaren can be satisfied with so the relationship improved. Even though Honda has been acquiring talents from outside in Europe etc aggressively under Hasegawa but it was still suffering from big corporate syndrome to some degree, but appointing an individual who knows racing well in a communication role between Sakura and Aoyama has made processes smoother. By that modification, Honda's atmosphere has become more aggressive and racy. One unnamed personel reckons that perhaps it was positive for Honda that such restructuring has been made by external pressure due to the turmoil of splitting with mclaren. [info in the article]

--

(new turbo)
(on introducing the new 2nd turbo and MGU-H for Vandoorne at this stage already) We haven't given up on clearing the reg of 4PU per season yet, but it's true that the outlook has become quite tough now.
(on the upgraded turbo and MGU-H) It's an update intended for performance improvement. Basically it is aimed at increasing compressor performance. In our case, compressor of TC and MGU-H are integrated, so we have no choice but to exchange both at once. There were various opinions regarding whether we should introduce it for this race or not, but considering the position we are standing in right now, we aggressively introduce anything as soon/long as we find something good / that improves performance even a bit, that's the stance. The reason for why we did not intend to introduce for both cars at the same time is that, although there was physical/logistical reason too, basically we wanted to confirm/verify its effect by introducing for / trialing on one car first.

(new intake)
both cars are fitted with upgraded intake system (which is outside 4PU/season rule)
>
both (turbo and intake) upgrades have been introduced earlier than originally planned
Regarding ICE as well, it is likely that we introduce new spec without waiting to go through 4 or 5 races.
[][]




Saturday
http://f1sokuho.mopi...no=107623&tt=-1
https://sportiva.shu.../11/___split_3/

(After the post-Quali meet the team press conference, EB and drivers headed to Honda hospitality to hold meeting for 30min, which was invited/proposed by Honda) It's certain that every one of team members are frustrated with current situation. This (13th and 16th in quali) is all we can get despite extracting max performance without issues, so it's natural that we are getting remarks from drivers like lack of power and bad driveability.
Of course the contents of the talk is serious. But it's what we do every race weekend, this year too, we are doing this many times already since pre-season testing. Today, we proposed to have talks, so we gathered.
We explained how current situation is like and what we are thinking on it. for example today as well we had an instance where engine failed to start for the reason that's not on Honda side, but with the state of current situation, drivers tend to misunderstand and think that it's engine problem again.
so we think it is important to explain and strive to build trust relationship with drivers by having communication opportunities with drivers, in order to prevent misunderstanding in such aspects. So this meeting was not the first of such kind, but we are holding it every race. We are talking about not only negative things but also positive things as well.
In the talk I keep getting nagged all the time tho (laughs)
That we get pointed out those negative attributes is practically feedback, ie we can drive better if you fix there. Furthermore, drivers pointing out those things means they are not giving up yet.
As long as there is not performance enough to win, it's natural that we have tough discussion about it. Therefore we wouldn't like to tolerate such talks as giving up immediately etc.

https://jp.motorspor...いない-891274/?s=1
2017-04-08

(post Quali)
it's tough. That was all we could get out of full performance of both car and driver, so it's tough after all.
In terms of top speed there is not much difference from last race, but period of the top speed difference lasts longer, so it affects lap time more.

Car performance is about both car and PU combined. So, chassis must be quite good, covering the deficit of PU. For example Sauber is using last year's Ferrari, but it has got more power than ours. even then we are still faster than Sauber in terms of lap time, so.
The chassis is pretty good. How good it is, where it's positioned actually, we have no idea unless we put such competitive engine. But it's got better for sure. It's obvious that if the engine were more competitive, we would be able to go much forward.

No matter how small the upgrade is, drivers are telling us that they want to do it. Criticisms like lack of power, bad driveability etc, they say these to mean that they can go faster if we fix these issues. So they are not giving up at all. Of course it's true that they are frustrated with current situation though.

(on public talks/criticisms) I dont mean to sound apathetic, but it is inevitable that you get criticized/told like lack of performance until/unless you achieve victory, so. There are talks like team spiting and Alonso going out, but we don't like such things/talks to take place. But I think it's unavoidable/natural that such talk is happening as long as we dont have performance to win.

(regarding the new spec PU to be tested at post Bahrain GP testing) What we are bringing to / trying at Bahrain testing is significant enough. But it's not something that will turn things upside down, also it might not make much difference on surface.
What we are planning to introduce are quite a big "weapon" if look at each one individually. But the gap to others is quite huge, so it's not like we can win immediately as soon as we've got updates.

(for the race) If it's wet condition, power range should drop, so the PU disadvantage factor will be smaller. At the moment driveability is an issue, so that's a concern, though. But our drivers are good in wet, so that'll be advantage obviously.
[][][]




Sunday
http://f1sokuho.mopi...no=107727&tt=-1
https://jp.motorspor...シャルはあった-891989/
https://sportiva.shu.../11/___split_3/


(Stoffel's issue) As a symptom, the fuel pressure dropped and couldn't fire engine. Fuel didnt come to engine due to whatever reasons. It wasn't a problem on the engine side, so it must be an issue somewhere in fuel tank again.
Actually problems like this occur sometimes. It happens by fuel running out as well, but it cannot be about empty fuel this time, so...if it was final lap, that might be the case.
Stoffel was saying "can't we reboot the thing to solve it?", but that wasn't an issue of that sort.

Fernando had good pace so if he had continued he would've scored points. It was down to the driver to quite a degree certainly, but including that, today we had potential as a comprehensive package enough to aim for points. Track condition was damp which is yet another factor that worked in our favor, but we were able to make decent performance in quali of dry condition as well, so. It wasnt bad pace wise. Of course we benefited more relatively because there were some drivers who have dropped out due to the influence of wet condition, though.
Pure performance wise, currently we are somewhere between 13th or 15th and 20th in the pecking order. The positioning changes by trivial factors and there might be instances where we can reach points. So I dont say we cannot score points, but at the same time asked if we can score points purely on merit, that's difficult, that's difficult, that's where we are right now I reckon.
(it was expected that it would be tough race for Honda but actually Alonso managed to hold rivals somehow?) One thing is that we are not as bad as we are said to be publicly. I reckon that we are positioned on the verge of points or no points, similar to last year. However that's not a position we have been aiming at. Therefore we say we are far off from the expectation.
(troubles at this race weren't down to PU, meanwhile issue on car side seems to be becoming conspicuous?) We are competing as mclaren-honda comprehensively, so. But there is no denying/doubt whatsoever that the major factor for lack of speed is the engine. So we must work harder on both reliability and performance.

[][][]

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=======================================================================












Bahrain



Friday
http://f1sokuho.mopi...24&tt=-1&at=105
2017年4月15日

(FP1 trouble for Stoffel) coolant pressure of MGU-H has dropped, so we stopped the car (Nakamura)
(on changing PU) FP2 is held at the same hour as the race start, so it's very important session. Hence we prioritized actual running on track as much as possible. (Nakamura)

To be precise, we swapped everything except ES and CE. This spare unit is a package consisted of new, 2nd ICE and MGU-K combined with old, 1st turbo and MGU-H used in Melbourne. (Nakamura)
(but in FP2 it encountered the same issue again) it wasnt a drop (of water pressure in MGU-H) as sudden as it was in FP1, so we asked him to come back to the pit on his own slowly. (Nakamura)
Water has leaked to the outside, so it's finished. We must exchange the unit.

- SV's FP1 MGU-H: 2nd and upgrade spec unit introduced in China
- SV's FP2 MGU-H: 1st and prev spec unit introduced at OZ

Last year we encountered similar troubles. This time's trouble is the same in terms of symptom. Presumably the seal has come off. We have strengthened the component/structure to some degree, but there may still be fluctuations in quality. That means that the reliability of such aspect has not been established properly yet. (Nakamura)
Will contact/talk with Sakura to decide which spec of MGU-H to introduce as 3rd unit (Nakamura)
[][][]




Saturday
http://f1sokuho.mopi...959&tt=-1&at=75
2017年4月16日

(On Alonso issue in Q2) Same trouble as Stoffel's on Friday. Bearing has got stuck/adhered. Since it's sealed by the rotation of the bearing, if the bearing gets stuck, water leaks from the bearing shields, seems that's what happened.

This race is the 3rd race for Alonso's PU, and its mileage has reached 1,300km. Of course it has completed 4,000km and 5,000km on dyno. However it was the first time we've covered this much mileage as actual on-track running in this season, including testing. We havent been able to make running in real environment, hence there's always chance that something would break. There is no way we can complain if we get criticized that that was the level of our reliability after all.
We will dismantle it and use the components again that are not broken. But we are going to exchange the whole package because there is no time to swap turbo only.
[]



Sunday
http://f1sokuho.mopi...999&tt=-1&at=45
https://www.as-web.jp/f1/111160?all
https://sportiva.shu...lit_6/#cxrecs_s


It was truly horrible weekend, and it's such miserable situation...
--

>> MGU-H <<

Stoffel Vandoorne
FP1
- 2nd MGU-H unit
- used in: China FP1(4), FP3(21), Q(6), race(17) ~ Bahrain FP1(10) ............58laps in total

FP2
- 1st MGU-H unit
- used in: Australia FP1(14), FP2(33), FP3(9), Quali(7), race(55) ~ Bahrain FP2(8) ...............126laps in total

Race (on the grid)
- 3rd MGU-H unit
- used in: Bahrain FP3(15), Quali(8) ...............23laps in total


Fernando Alonso
Quali
- 1st MGU-H
- used in: OZ FP1(18), FP2(19), FP3(7), Quali(15), race(50) ~ China FP1(5), FP3(17), Quali(13), race(33) ~ Bahrain FP1(14), FP2(31), FP3(10), Quali(8) ............231laps in total

--
(on Stoffel's issue) water pressure of MGU-H dropped during installation lap
we pumped water to increase pressure on the grid but it has been identified that water pressure cannot be maintained, so we decided to retire.
(on MGU-H issue) The issue has occurred at such early stage so that the mileage is unlikely to be the cause, besides it has happened as many as 4 times hence it's unlikely that it was due to anomaly in quality of particular components. Regarding Fernando's, the component that covered almost 1,300km in the past 2 races suddenly broke down here. With such frequency, we are suspecting factors peculiar to Bahrain such as sand issue and specific corners to be the cause, but anyways we havent identified the clear cause yet.
As far as the cause is not identified, we do not exclude any possibilities.
MGU-H issue (for both cars): burnt/adhered bearing -> sealing compromised -> coolant water leak [info in the article]
Honda will analyze oil to check the amount of dust in it etc [info in the article (according to Honda")]
We are absolutely going to rectify it for next race in Russia. If you cannot do it, you better not come anymore. We are determined to take countermeasures no matter what.
[][]
=======================================================================
=======================================================================







 
Sochi


https://www.as-web.jp/f1/114253?all
http://www.as-web.jp/f1/114633?all
https://sportiva.shu...9/f1___split_7/
2017.04.28


(regarding the reported topic of rescue deal to be contemplated at strategy group meeting held on 25 April)
Such subject has not been discussed at all actually. Suppose there is a gap of more than 0.3sec/lap, there is no ongoing discussion regarding rescue measure to make up the gap. (Hasegawa who attended the meeting)
What was being discussed about at the point of last year was about fixing/locking the current PU regulation until 2020, and about reviewing/easing the regulation if the PU performance difference between makers is still significant this year. For example, make it token-free, ease the number of PU components limit per season reg, and so on, but not such thing as rescue measure. In fact, the standard and method to measure the performance difference is still ambiguous and no conclusion has been reached, plus such talk hasn't been even put on table at the April 25 meeting either.
Of course we haven't made such request, and there is absolutely no way we as Honda are going to make such request. There is a possibility that regulation may be altered for reasonable reasons, such as, that this part(s) of regulation should be too hard for new entrants. However, we consider that there must not be such case where you ask for favor just for your own benefit/convenience unfairly.
But situation where such reports are being made is extremely embarrassing, of course.

Merc has increased output by 20hp since last year. Ferrari was behind Merc by about 10-15hp at the end of last year, but thanks partly to poaching many engineers from Merc, they are roughly on par with Merc this year. The gap b/w Ferrari and Renault at the end of last year was about 30hp, with Honda further 20-30hp down from that. (anonymous undisclosed "PU maker personnel" quoted)


(regarding the report of Merc consultancy)
That's impossible. I have nothing to comment about anything based on assumption.

At MK, job interviews for engineers who wish to join Honda from Merc etc are conducted often. As for working at Sakura, if permanent status at Sakura is difficult, short tenure like 3 months is offered as well, also offered is the involvement as a sort of consultant at MK. Training of younger engineers tends to be overfocused, but actually poaching quite a few experienced engineers from production departments etc for F1 as well. [info in the article]

(some say Honda might be lacking passion for racing, working with corporate mindset?) There is no single staff who's being optimistic or working on it on easy mode. No doubt about that. Lack of expertise and experience for sure, it may be true that we are behind compared with those people who've been doing F1 continually for decades. However all of us are working on it with utmost spirits. We must prove our worth properly by catching up rivals firmly.
As I always say, result is everything about the race, so current state of Honda is unacceptable. We must do something. I dont want to receive words like "Honda has potential" or "Honda is doing well" for such state of ours. Of course we think we have potential/room for improvement/growth as long as we pursue/proceed the development, so we will definitely obtain accomplishment no matter what, at any cost.
--

Bahrain test
- ran with the same tentative countermeasures on MGU-H for 1st day and 2nd day
- encountered trouble in lap 2 on 1st day but that was due to different matter
- were able to confirm the validity of the countermeasure itself on 2nd day of testing by completing 81laps
[mishmash of Hasegawa&Nakamura quotes and "info in the article"]
(on series of MGU-H troubles at Bahrain GP) as a result of analysis, it turned out that there is no possibility of dust/sand entering oil system. However it is possible that hot temp at Bahrain was affecting it (Nakamura)
the cause of adhered MGU-H bearing is reverse flow of oil
There was mechanical trouble in bearing, so we took countermeasures against all the possible causes such as temp, hydraulic flow malfunction etc. But we dont know yet if it's really enough or not.
- For Sochi, brought revised/upgraded MGU-H with further reinforcement applied based on what has been learned in Bahrain test, such as modified hydraulic flow/piping structure and heat management
- 3rd MGU-H of SV's (the unit that failed on grid in race) is not completely broken so still usable, so may continue to be used as a Friday unit
- there is no problem in FA's PU at Bahrain race, its 2nd MGU-H is usable too but has been exchanged with the new upgraded unit
[info in the article]

[][][]





Friday
http://f1sokuho.mopi...410&tt=-1&at=15
2017年4月29日
(Stoffel's MGU-K issue in FP1) MGU-K's drive shaft has broken mechanically/physically. But that was due to the mileage of the component. According to dyno testing, it was supposed to last bit longer, but has broken earlier than expected. It's disposable parts that can be exchanged freely.
But in order to exchange the parts, you have to not only dismantle PU from chassis once but also detach MGU-K from the unit to investigate. It takes too long for that, so it would impossible to get ready in time for FP2. So talked with mclaren and decided to give up on analysis/exchange work and swap the whole unit. [info in the article]
Introducing 5th element at this stage is totally unexpected, and big trouble.

this time's MGU-K trouble is merely about maintenance/disposable parts breaking down earlier than expected, so not serious issue such as design flaw. This trouble has happened in JB at the race of Bahrain last year. At that time it was not drive shaft but bearing that has failed, but anyways upon encountering the trouble we reviewed the maintenance cycle to re-set it shorter. Drive related components around MGU-K do not last 4,000km, so you are allowed to exchange them freely without incurring penalty by regulation.

(on swapping PU in time for FP2) Team has done amazing job. I appreciate hard work of all the team members.
()[]





Saturday
http://f1sokuho.mopi...450&tt=-1&at=15
2017年4月30日

(Nando's lap) it was super lap. Regarding Stoffel, seems he struggled to warm up tyre by getting stuck behind Riccardo on the outlap
I don't deny we are beaten on power. As drivers say, there is nothing driver can do on the straight, so.
[][][]





Sunday
http://f1sokuho.mopi...492&tt=-1&at=15
2017年5月1日


(on Alonso's trouble)
During the formation lap, we encountered malfunction that MGU-K power is lost due to ERS system failure. We tried to restart it during heading to the grid, but we couldnt recover well so had to stop the car on the track, unable to start the race. The attempt ended up fail after all.
MGU-K didnt function at all. It's the same issue that has happened to Stoffel in OZ race, in his case we were able to reboot it successfully at the pit during the 1st stop, but this time it happened during formation lap, If you come into pit during formation lap, you have to start from the pit, so decided to reboot the system on track.
This time as well, if we had had him return to the pit we would've been able to reboot it definitely. So in hindsight we should've chosen pit start.

(After post-race briefing Alonso called/caught Hasegawa to have one-on-one meeting) Fernando exploded his anger at me saying "too many problems, what are you going to do". I can only apologize for that, and had no other choice but to reply and promise "we will solve it". Certainly it's unacceptable to have this many reliability issues in 4 races, no matter what the reasons are. Cause for each issue is different/unique, so we have no choice but to crush one by one. If asked how much left, I have no word to return tho.
The opening 4 races exposed our lack of capability. The issues on both performance and reliability has become evident. On the other hand, we've also found out that as long as we finish the race the car itself is at decent level, so if we manage to improve performance and increase the power, we should be able to make better fight, I reckon
"I have no idols. I admire work, dedication & competence."

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diffuser
230
Joined: 07 Sep 2012, 13:55
Location: Montreal

Re: Honda Power Unit

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wow, that was a really good read.

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godlameroso
309
Joined: 16 Jan 2010, 21:27
Location: Miami FL

Re: Honda Power Unit

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gruntguru wrote:
08 May 2017, 04:59
godlameroso wrote:
08 May 2017, 04:18
Then perhaps a happy compromise between the two, entry ports and flame ports on the pre-chamber that work with small one way valves. The pre-chamber entry opening allows A/F mixture in during compression, and closes during combustion, exiting instead through jet holes.
I think the system (TJI) works fine as-is with optimised jet hole diameter.
Would any EGR effects be present, and would one work with or try to eliminate said effects?
Saishū kōnā

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MrPotatoHead
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Joined: 20 Apr 2017, 19:03
Location: All over.

Re: Honda Power Unit

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glenntws wrote:
07 May 2017, 23:58
I understand your Problem and I also think we could explain this a bit better. So I will try that :D

Since the pre-chamber is mostly likely fed by the main-chamber charge without it's own injector, it's important to not only achieve a good "cleaning" of the pre-chamber during the exhaust stroke, but also controlling the fuel concentration of the part of the mixture which goes into it.

To feed the pre-chamber precisely, you need to control the fuel injection timing to the right position of the piston and most impportantly to the right movements in the main chamber. This heavily depends not only on intake Timing,but also to the intake port shape. If you have a side-mounted injector, the goal would be to create a heavy charging motion with a tendency to create a big swirl counterwise (if exhaust is right and intake is left). This is exactly achieved by having a "mountain"-type piston and a very high angle of the intake port.
If you achieve this, you are able to allow a charge motion into the pre-chamber. This can be intesified with a asymmetric design of the pre-chamber. Now for the mixture part. If you have your tumble motion you need to time the injection properly to allow the injector to almost directly inject the fuel into the chamber with one fuel jet, or you decide to inject the fuel primarily into the main chamber ant time it correctly to allow a richer mixture in the pre-chamber. The first option is simpler for operation but harder to construct because you need to have a "extravagant" Sport for the injector, the later is harder to controlm but way simpler to contruct.

The second Problem is the "cleaning". This heavily depends on the timing of the exhaust valves and the overlap, but also very strongly on the shape of the pre-chamber, because it (in cooperation with the main chamber design) has to allow the charge to leave the chamber properly without getting into much trouble with the main charge motion.



Now, if you think these are all just simple expectations from me: They're not. This is based upon the simulations I've made with my own project. If you have interest, I could tell you a bit more about the charge in multiple photos in the next days, but for know I have one picture, where you can see how the ports, the main- and the pre-chamber look like.

If you wonder how this engine will work: Using direct injection and trying to directly feed the pre-chamber during the compression stroke, the goal is to achieve a slightly richer mixture in the pre-chamber (which makes up about 22% of the volume at TDC) and a slightly lean mixture in the main-chamber to average on a stochiometric level. The idea is a combustion, which always firstly occurs in the pre-chamber to auto-ignite the outside mixture in a form of HCCI.

The pre-chamber mixture is the "pressure booster" in the ignition cycle and allows to combine full control with a high efficiency. The pre-chamber mixture can be auto-ignited after the HCCI-principle if the engine is in the right operation engine (which get's increased by the possibility of a richer mixture) of with a spark plug.
To allow a high-efficiency combustion in the pre-chamber even with spark-plug operation, the pre-chamber is designed asymmetrically to achieve extremely high levels of turbulence which allows for very fast combustion.
While nice renders your theory of operation does not match the reality of a turbocharged engine when it comes to valve overlap and events. Nor does not match with reality in my experience.

But Please feel free to show more evidence of how you think it works.

Vortex37
Vortex37
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Joined: 18 Mar 2012, 20:53

Re: Honda Power Unit

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gruntguru wrote:
08 May 2017, 01:24
PlatinumZealot wrote:
06 May 2017, 18:52
I think there is a special mechanism at play to get that rich mix in the prechamber and to have the proper jet action. I have a few ideas.... Might just mention one now.

idea #1... More than one injector is used (loop hole)
You all already know my first idea already. That two injectors are used. One in the chamber and one outside it.

Idea #2 - boosted EGR used for ignition

My other idea is that a hig pressure EGR pump is used. This pump distributes hot high pressure gasses from the exhaust into the pre-chambers of the different cylinders. The pump raises the pressure to above compression prrssure and solenoid rleases the hot gasses into the prechamber. A plasma may or may not be made from these gases on their way to the chamber.
The jets are made and ignition occurs in the main chamber.
It could be as simple as:
The direct injection nozzle sprays roughly in the direction of the pre-chamber. Any fuel sprayed during the intake stroke will be mixed through the main chamber by the tumble action. When the compression stroke begins, some of this air-fuel mix flows into the pre-chamber. (The quantity of mixture in the pre-chamber increases by about a factor of ten during the compression stroke). If the injector is operated again at a time where this inflow to the pre-chamber is high, the pre-chamber mix will benefit from this extra fuel since the main-chamber at this point is stratified - with rich mixture in the vicinity of the pre-chamber.

From there it is easy to see the pre-chamber will contain a richer mixture than the main chamber. The richness of the pre-chamber can be controlled by biasing fuel delivery toward either the early injection event (leaner pre-chamber) or late injection event (richer pre-chamber).
To extend what you are saying. I am still sticking with the idea of a coaxial/concentric combined prechamber with igniter, the injector wrapped around it. Since multiple injection events are allowed, a very short (time) injection, as you mention during compression stroke, would be effective in enriching the mixture entering the prechamber. However I don't see a problem with the prechamber mix, because it is really small in relative terms, and has a high energy igniter. I am also sticking with the idea of a stepped bowl piston, which would help with keeping a stratified charge.

Vortex37
Vortex37
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Re: Honda Power Unit

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dren wrote:
08 May 2017, 15:30
I think something similar like this was posted before. What if the pre-chamber is made into the piston? The injector could then have two or more injections during a cycle, one for the lean full cylinder AFR, and one right before ignition for the rich chamber.

https://s4.postimg.org/u9cxny7v1/Untitled.png
Yes. I also think along the same lines about the piston. But I would have a coaxial prechamber/igniter and injector. Mercedes are using a stepped bowl in their new straight six series both petrol and diesel. It keeps the combustion in the central area and evens out pressure across the piston.The edge of the piston has a slight inward slope. This concept is well known by diesel folks.

Image
New turbo Merc straight six series - to show stepped bowl piston

JuanjoTS
JuanjoTS
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Re: Honda Power Unit

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You could place the mini combustion chamber right where the exhaust valve is.
The walls of the combustion minicamera do not have to be smooth, they may have ways to create turbulence.

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gruntguru
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Re: Honda Power Unit

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godlameroso wrote:
08 May 2017, 18:32
gruntguru wrote:
08 May 2017, 04:59
godlameroso wrote:
08 May 2017, 04:18
Then perhaps a happy compromise between the two, entry ports and flame ports on the pre-chamber that work with small one way valves. The pre-chamber entry opening allows A/F mixture in during compression, and closes during combustion, exiting instead through jet holes.
I think the system (TJI) works fine as-is with optimised jet hole diameter.
Would any EGR effects be present, and would one work with or try to eliminate said effects?
There would be some residuals trapped in the pre-chamber but less than 10% of the pre-chamber volume, which itself is less than 2% of total TDC volume so less than 0.2% EGR due to this factor.
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PlatinumZealot
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Re: Honda Power Unit

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dren wrote:
08 May 2017, 15:30
I think something similar like this was posted before. What if the pre-chamber is made into the piston? The injector could then have two or more injections during a cycle, one for the lean full cylinder AFR, and one right before ignition for the rich chamber.

https://s4.postimg.org/u9cxny7v1/Untitled.png
Nope. I think that is a moving target in literal sense. Your chamber size and nozzle opening is constantly changing size and shape and timing would be pinned to set geomterical position of the piston to get the optimum. And in F1 there is too much to lose by not veing at the optimum.
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JonoNic
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Re: Honda Power Unit

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Is it possible to aim the injector and squirt directly into the flame kernel thus creating a similar combustion to tji? Or would that destroy the injector nozzle? Would the injection be faster than the growth of the flame kernel? Isn't the aim to create a faster combustion?

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Sasha
Sasha
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Joined: 07 Jul 2013, 07:43

Re: Honda Power Unit

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Dual-stage injector with multi-pattern/path spray.(add adj. fuel heater to just make it more complicated) :wink:


Solve your problem of fuel in pre-chamber and main-chamber.
Last edited by Sasha on 09 May 2017, 07:29, edited 1 time in total.

phezzy
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Joined: 27 Jul 2010, 13:03

Re: Honda Power Unit

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If you had a 'stepped bowl' piston, would there be enough pressure from combustion in a lateral direction to cause more vibration in the cylinder walls? (By pushing the head sideways as well as down?) I know nothing about this, but just a thought. With a regular flat head piston the pressure would be more vertical and so less vibration. Or would it all equal out so as not to be an issue...?


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