Honda Cackle theory

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
Mudflap
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Re: Honda Cackle theory

Post by Mudflap » Sat Mar 31, 2018 1:08 am

Burning the fuel in the exhaust port is basically a Brayton cycle with very low pressure ratio and an inadequate combustor. Since the most efficient gas turbines have thermal efficiencies below 40% for a simple cycle that would literally be equivalent to dumping fuel through the tailpipe.

It makes no sense to do this when you can harvest at part load directly from the ICE to K to H to ES

In order to advance a discipline one must first have an excellent understanding of the basics. Anything less is destined to fail.
How much TQ does it make though?

muramasa
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Re: Honda Cackle theory

Post by muramasa » Sat Mar 31, 2018 2:26 am

Zynerji wrote:
Wed Mar 28, 2018 7:15 pm
I am interested in anyone's thoughts concerning this idea. Using the VLIM as a pressurised pre-chamber to cause an afterburn after the exhaust valves open could potentially help the spooling of the turbo, and also cause the cackle that only the Honda has.
If "cackle" means that brrr sound on partial throttle, Hasegawa himself answered about it back in 2016 (Mexico GP weekend).
http://www.as-web.jp/motorsports/shots% ... C%E3%81%B5

Here's the relevant part (translation by me)

///
------- Also one question from me (photographer Mr Atsuta), when I was taking photos at the entry of a corner, I felt the sound of backfire was particularly loud from Honda engines only?
Current F1 engine is not good at lower speed range, so in such instance you often keep the throttle open bit excessively then cut fuel etc in order to adjust torque, therefore back fire gets bigger for that amount. I think other makers are doing the same too, but we are doing it in particular, more than any others.

-------- Is it about improving pickup or pedal response at lower speed range?
That's correct, you let engine take in a lot of air. Then inject fuel in there as normal/usual, then shift ignition timing, or stop some cylinders, in order to lower/control the output level. By doing that, there is excess/redundant fuel at the timing of mode shifting, which then comes out of / goes into the exhaust pipe.

-------- I remember there was not such thing at USA and Suzuka?
The basics are unchanged, but there are some fluctuations (depending on track characteristics).
///

So nothing special, just a way of controlling and maintaining torque at low rpm range. You can hear other engines are sounding same/similar too, Ferrari in particular altho not as blatant or can I say dirty as Honda obviously, even Merc sometimes, Renault not much perhaps.

johnny comelately
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Re: Honda Cackle theory

Post by johnny comelately » Sat Mar 31, 2018 9:40 am

Mudflap wrote:
Fri Mar 30, 2018 10:04 pm
Zynerji wrote:
Thu Mar 29, 2018 11:45 pm
Mudflap wrote:
Thu Mar 29, 2018 9:51 pm
That is a THROTTLE

This is what they use in F1 for throttles - similar to that patent:
http://www.racetothefinish.co.uk/media/ ... g_9111.jpg

A VLIM is a device that changes the effective length of the runner so that the resonating frequency of the pipe is tuned at any engine speed. A VLIM is not a throttle. Do you understand this ??
Great! Now put that in the VLIM stack close to the Intake port itself, and realize that when it is closed, but the intake valve is open, that the piston can compress the mix back into that runner, seal it by closing the intake valve, then releasing it again during the exhaust valve overlap, either flushing the cylinder with fresh air, or causing a secondary ignition if there is fuel included in the pressurized charge.

I agree with the other poster. Please explain why this is silly, or mythical, instead of just shitting all over the concept and flying away without any relevance.
First of all you came up with this complete bananas theory and the only benefit that you have pointed out is that it can potentially help spool up the turbo ? Must be of great help when the turbo has a freaking electric motor attached to it which is meant to do exactly that but much more efficiently than burning fuel somewhere in the exhaust port.

Let's assume for a second that Honda are completely bonkers and somehow designed this insane system than can actuate each individual trumpet 125 times per second (does sound crazy when you spell it out right?).
You are proposing that the VLIM blocks the flow and the piston actually pumps the charge back through the inlet valves. This is effectively reducing the compression ratio and increases the pumping losses. At the same time you aren't getting the benefits of the VLIM (it's closed, so no pulse reflections) so you also lose volumetric efficiency.
Then it gets even crazier - you somehow burn the stored charge during exhaust (at an extremely low efficiency, unless you propose that they also have a combustor somewhere in there) for the sole purpose of spooling up the turbo.

How does this make any sense at all ?
Some of the assumptions made here are not quite correct because we have run one of these specifically to experiment with effect at overlap on a boosted engine. it was rotated at cam speed and with adjustability of opening and closing and duration it was very effective under some circumstances.

NL_Fer
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Re: Honda Cackle theory

Post by NL_Fer » Sat Mar 31, 2018 10:19 am

Will not work.

Using first part of the compression stroke to pressure the VLIM will lose compression in the cilinder. To compensate for that the Turbo has to work harder to increase the pressure to start with. Any gains made are allready needed to for the compressor in the first place.

henry
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Re: Honda Cackle theory

Post by henry » Sat Mar 31, 2018 10:23 am

NL_Fer wrote:
Sat Mar 31, 2018 10:19 am
Will not work.

Using first part of the compression stroke to pressure the VLIM will lose compression in the cilinder. To compensate for that the Turbo has to work harder to increase the pressure to start with. Any gains made are allready needed to for the compressor in the first place.
The geometric compression ratios are high, or so it would appear since the FIA have seen fit to restrict them to a max of 18.

So maybe LIVC which reduces the effective CR to something more normal is not so unlikely?
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus

Mudflap
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Re: Honda Cackle theory

Post by Mudflap » Sat Mar 31, 2018 2:18 pm

johnny comelately wrote:
Sat Mar 31, 2018 9:40 am
Mudflap wrote:
Fri Mar 30, 2018 10:04 pm
Zynerji wrote:
Thu Mar 29, 2018 11:45 pm


Great! Now put that in the VLIM stack close to the Intake port itself, and realize that when it is closed, but the intake valve is open, that the piston can compress the mix back into that runner, seal it by closing the intake valve, then releasing it again during the exhaust valve overlap, either flushing the cylinder with fresh air, or causing a secondary ignition if there is fuel included in the pressurized charge.

I agree with the other poster. Please explain why this is silly, or mythical, instead of just shitting all over the concept and flying away without any relevance.
First of all you came up with this complete bananas theory and the only benefit that you have pointed out is that it can potentially help spool up the turbo ? Must be of great help when the turbo has a freaking electric motor attached to it which is meant to do exactly that but much more efficiently than burning fuel somewhere in the exhaust port.

Let's assume for a second that Honda are completely bonkers and somehow designed this insane system than can actuate each individual trumpet 125 times per second (does sound crazy when you spell it out right?).
You are proposing that the VLIM blocks the flow and the piston actually pumps the charge back through the inlet valves. This is effectively reducing the compression ratio and increases the pumping losses. At the same time you aren't getting the benefits of the VLIM (it's closed, so no pulse reflections) so you also lose volumetric efficiency.
Then it gets even crazier - you somehow burn the stored charge during exhaust (at an extremely low efficiency, unless you propose that they also have a combustor somewhere in there) for the sole purpose of spooling up the turbo.

How does this make any sense at all ?
Some of the assumptions made here are not quite correct because we have run one of these specifically to experiment with effect at overlap on a boosted engine. it was rotated at cam speed and with adjustability of opening and closing and duration it was very effective under some circumstances.
Really, you ran "one of these" ? A bit difficult I imagine since they only exist in Z's imagination.
Which assumption regarding this entirely fictitious device is not correct ?
How much TQ does it make though?

muramasa
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Joined: Thu Oct 05, 2017 3:33 pm

Re: Honda Cackle theory

Post by muramasa » Sat Mar 31, 2018 3:34 pm

Mudflap wrote:
Thu Mar 29, 2018 10:43 pm
Zynerji wrote:
Thu Mar 29, 2018 10:12 pm
Mudflap wrote:
Thu Mar 29, 2018 10:07 pm
Welcome to F1 mythical.

"Because the turbocharger was inside the V-bank. the induction system was oriented quite forcefully. When I first saw this I couldn't help but wonder. 'will this really work?' We were starting with a fresh mindset. but that resulted in us being unable to overcome reliability and performance hurdles.

New regulations in 2015 allowed for variable intake systems. Such systems are usually used to change the stroke of the intake funnel. increasing the charging efficiency. Combined with a turbocharged engine, simply increasing the charging efficiency does not necessarily increase output, so the system is sometimes manipulated to shut out air.
Either way. variable intake technology leads to an increase in output.
so Honda adopted it without hesitation."

https://www.reddit.com/r/formula1/comme ... h=d3ef5235
It's not clear at all what they mean by that. To interpret it as variable valve timing or afterburner (really?) is silly.

I've done cleanup:
------------------------------------------
"(Talking about 2015 unit here) Because the turbocharger was placed inside the V-bank, the induction system was forced to take heavily compromised config as well. When I first saw this, I couldn't help but wonder, 'does this really work?' We, for one, made a start (on r&d) with a fresh mindset, however we were stuck in a situation where we were unable to specify/identify the exact matters (what to work on/solve/etc) nor overcome immediate hurdles in terms of both reliability and performance."

Reg change in 2015 allowed the introduction of variable intake system. Generally VIS is used to adjust and control the stroke of the intake funnel according to the engine rpm in order to increase the charging efficiency. Meanwhile one thing to note is that, on a platform of turbocharged engine, increasing the charging efficiency does not necessarily/always deliver output increase, so there are also cases in which the system is used to control the charge state in a way to prevent air from being inhaled as well. In whatever way and form, VIS is a technology that brings improvement in PU performance for certain, so Honda decided to adopt it without hesitation.

(then continue on to talk about how 2015 plenum chamber and VIS was compromised and complex at the same time due to packaging restriction, then to how they revolved and improved the whole intake design in 2016 then 2017)
------------------------------------------

It's nothing special, the first paragraph is the engineer's remark. In that whole section including the excerpt, he's merely saying turbo, inlet manifold layout and VIS were massively compromised and flawed due to sizing/packaging restriction in 2015 unit, and explaining/describing how they were in a maze and tackling with difficulties at that time. The second paragraph is a general explanation on VIS by the author as is clear now. Frankly I have no idea why Zynerji thought that part was crucial, the whole article is about explaining and tracing the process and journey of R&D from 2015 to 2017, there are many intriguing and revealing stuffs in there for sure but not the kind of stuff he seems to be finding out, but that translation is not so accurate so perhaps misread as if there must be something "extraordinary" written/hidden in there.