Honda Power Unit Hardware & Software

[63l8qrrfy6]

Surely lift will more or less halve with 2 valves so displacement will also halve.

Nothing in the discussion led me to assume that, rather I assumed the simple case of two springs for two valves vs one spring for two valves.

If you want to compare 2v to 4v heads on the same engine - OK the lift will reduce somewhat (not halved because valve diameter won't halve) and of course the valve mass will reduce (significantly since mass is proportional to somewhere between the 2nd and 3rd power of the valve diameter) - all-together a very complex proposition to try and make assumptions about.

Fair enough - I suppose PZ's question about modifying it for 2 valves was very open-ended.

(unlike coil springs) the above types avoid the combination of substantial bending and torsional loads

Well coil springs are only loaded in shear unless coil clash occurs in which case there's high herz stress. There shouldn't be significant bending stresses in a coil spring.

With a torsion spring, the outer shaft will be loaded in both torsion and bending.

I am sure it's the other way around - the combination of torsion and bending is worse in a torsion shaft spring

[PlatinumZealot]

It doesn't matter. Let's say for argument's sake that the original valve has 2xDia lift. The reasonable assumption is that the smaller double valve will also have 2XDia lift. This means roughly half the lift of the original valve.

I gave another example of when BMW updated the M20 engine, which was a 2 valve per cylinder, to the M50, which is 4 valves per cylinder. Same bore, same displacement, almost the same valve lift. Later variants of the engines had higher lifts of course, but nowhere near the half lift. I am only giving a practical example - not arguing with your theory.

2 valves M20B25: 256 deg, lift – 10.1 mm
4 valves M50B25: 240 deg, lift – 9.7 mm

[Hino]

@Hino, that it is, would love to see the development between the two years (and two philosophies)

It will be a couple of days til I can get it finished. Here's a little snippet that mentions a Tanol additive to fuel mixture.

[Wazari]

@Hino, that it is, would love to see the development between the two years (and two philosophies)

It will be a couple of days til I can get it finished. Here's a little snippet that mentions a Tanol additive to fuel mixture.
https://i.imgur.com/ZKH1KhA.png

Yes, this is from the 2016 season.

[Tommy Cookers]

'Tanol' ?

does this mean Ethanol ?
or hopefully a higher alcohol eg Butanol (for the 5.75% compulsory bio fuel content)

(bio) Butanol is preferable due to its much greater heat content per kG (than Ethanol)
with 5.75% bio ethanol a 100 kg tankful of fuel mix would have 97% of the energy of 100 kG of fuel without the bio ingredient
with 5,75% bio butanol a 100 kG tankful of fuel mix would have 99% of the energy of 100 kG of fuel without the bio ingredient
the rules demand demonstration of a commercial link to credible biofuel production
and eg bio Butanol can be used as a feedstock for non-bio conversion to a more advantageous 'bio' fuel ingredient
even in the UK until recently there was an active trial BB plant

btw
alcohols have a greater heat content per kg of combustion air (than gasoline)
ethanol roughly 5% greater, methanol roughly 10% greater and butanol roughly 15% greater
traditionally ie with engines air-limited eg the 2.4 litre NA V8s this was a useful property
but it does not benefit current engines because they use unlimited air


Note to self - re the following post by Sing
I seem to have posted less than a year ago about bio isobutanol (the above talk about bio butanol is due to brain fade)
the exact composition of bio butanol is unclear - maybe it's a mix of different butanols and the naming is unimportant

the 2009 thread 'New way to uncap engine regs .....' may be the first mention of bio butanol
and searching this section of this forum for bio isobutanol will yield some worthwhile posts
eg 'Roadside ethanol E85 ....' thread Oct 2013

[Singabule]

t-butanol has octane ratings of 105 RON and 89 MON.[32] t-Butanol is used as an additive in gasoline but cannot be used as a fuel in its pure form because its relatively high melting point of 25.5 °C (79 °F) causes it to gel and solidify near room temperature. On the other hand, isobutanol has a lower melting point than n-butanol and favorable RON of 113 and MON of 94, and is thus much better suited to high fraction gasoline blends, blends with n-butanol, or as a standalone fuel.

[Rodak]

Hino, in reference to your chart, maximum fuel flow rate is achieved at 10,500 rpm and stays constant to the rev limit (15,000 rpm).

From the 2018 Technical Regulations: 5.1.5 Below 10500rpm the fuel mass flow must not exceed Q (kg/h) = 0.009 N(rpm)+ 5.5.

[wuzak]

https://www.autosport.com/f1/feature/78 ... larenhonda

"It's fair to say the starting level was almost equivalent from last year - peak power was almost equivalent, but low- rpm power was very down," Hasegawa concedes. "It had huge gaps from something like 9000-10,000rpm - no torque. It's OK on the dyno, but when we used upshift and went from 10,000 to 9000, torque decreased dramatically.

"It will create a big oscillation. The dyno's inertia is huge, so it doesn't create a big problem, but the inertia of the car itself is much less. Such a big torque drop was creating a big oscillation."

This made the car extremely difficult to drive (when it was running) until Honda modified the intake system for May's Spanish Grand Prix, which helped recover the lost bottom-end power and driveability. Until then, the drivers were forced to change gear at odd points. You could hear the graunching sounds as the transmission protested the unusual upshift and clutch settings required to avoid this torque drop.

"Other than the target performance we very much had an issue with reliability," admits Hasegawa. "We had so many issues with the oscillation, and also the MGU-H bearing. It also comes from the oil blowing from the oil tank. The oil came to the bearing of the turbine and the turbine bearing was seizing or about to seize - that was creating an issue.

"The bearing itself was not changed from last year, although the package is different, but last year we didn't have such oil blowing from the oil tank because we had a conventional design. Actually, this is just an excuse - we studied very much for every area we changed - but we didn't allow for something besides that area, like the oil-tank configuration, so we had many issues that we didn't expect from our modification.

[ringo]

Can someone explain what Hasegawa is saying about the turbo bearing and oil tank and oil blowing?
Trying to understand how their poorly designed oil tank affected the turbo lubrication.

[FW17]

Can someone explain what Hasegawa is saying about the turbo bearing and oil tank and oil blowing?
Trying to understand how their poorly designed oil tank affected the turbo lubrication.

Something to do with oil air seperation in the oil tank not working as it should.

Since the tank did not remove the air completely from the oil the micro bubbles were causing poor lubrication of the mgu bearings which caused them to sieze.

[tok-tokkie]

I read that oil thing differently. It seems the bearings were getting too much oil & Seizing!. I expect the bearings are given oil mist lubrication & that now they got too much oil. But excess oil causing seizing as in the normal metal on metal seizing I do not understand. I also wonder how air in the oil supply makes the oil mist sytem deliver excess oil. Anyone else with a better understanding?

[Wouter]

Does anyone know if the Honda engine has improved in terms of reliability and horsepower during this winter?
Has anyone information about the progress in the factory? I am very curious.

[etusch]

Does anyone know if the Honda engine has improved in terms of reliability and horsepower during this winter?
Has anyone information about the progress in the factory? I am very curious.

I hope more powerful PU before reliability

[Wazari]

"Tanol" = butanol.
Oil tank issue was attributed to shape, PU location and mounting angles. This led to intermittent cavitation causing air to go into the supply line for the MGU-H. Slosh dynamics is very difficult to mimic.
Camshaft design is part witchcraft and voodoo. This version of camshaft is slightly unique due to a very complex intake and exhaust passages in the cylinder head. One reason for a slightly taller and heavier head. Point to ponder: think BMW motorcycle engine camshafts.
I hear dyno testing to date is no comparison to same time last year. Both in terms of power and reliability.

[OO7]

Camshaft design is part witchcraft and voodoo.

Wazari, would you prefer if the regs allowed for rotary valves http://home.people.net.au/~mrbdesign/PD ... echBRV.pdf, VVT and or Freevalve style systems?