Honda Power Unit Hardware & Software

[ENGINE TUNER]

There's also piston height itself, a thinner piston let's you use a longer rod, for the same throw, increasing the rod ratio.

We all know that these huge multinationals have long since have had programs that simulate and optimize most of these minor variables.

[JuanjoTS]

no more of my words wasted on your nonsense

Do not be angry, you are the one who has tried to ridicule me, I have tried to be gentlemanly.

[etusch]

Early design flaw
Some of the early CVCC engines had a problem with the auxiliary valves retaining collars vibrating loose. Once unscrewed, engine oil would leak from the valvetrain into the pre-combustion chamber, causing a sudden loss of power and massive amounts of smoke to emanate from the exhaust pipe. The condition simulated a blown engine, even though the needed repair was quite simple. Honda eventually came up with a fix involving metal retaining rings that slipped over the collars and prevented them from backing out of their threads

https://en.wikipedia.org/wiki/CVCC

[JuanjoTS]

There's also piston height itself, a thinner piston let's you use a longer rod, for the same throw, increasing the rod ratio.

We all know that these huge multinationals have long since have had programs that simulate and optimize most of these minor variables.

Are the most important and most complicated to obtain, elastic motors.

For the Honda concept to work, they must find that their maximum torque is linear between 10,500rpm and 13,000 rpm, something extremely complicated with the limitation of valves per cylinder.

The only way to overcome MER or FER is very complicated, you can match them by copying their dimensions, but to overcome them there is only one path, pistons and cylinders with double-effect controllable.

To improve Honda must forget limitation of 5 engines per season, must bring a new engine for China with the combustion chamber corrected.

[Tommy Cookers]

[quote=glenntws post_id=687670 time=1490640775 user_id=36928] .....Right. But the Problem they have to regulate throttle on shifts is because of harmonics. Even though a rough combustion is, just like you said, never good.[/quote]

doesn't the problem seem to be instability in the complex train of events needed to produce race-quality upshifts ?
(ie at a frequency an order or two of magnitude lower than anything to do with the crankshaft frequencies)
the complex train of events that can fail if pickup after turndown is inconsistent because of combustion inconsistency

[dren]

That coupled with the 100% torque demand that goes along with most up shifts coupled by an immediate drop in revs. Downshifts requiring far less torque demand or even negative.

More precise control of the other systems (turbine/compressor/K/H) may not be quite to what is required for combustion stability during abrupt changes in operating conditions.

[godlameroso]

It's not so easy to introduce new engines so quickly.

[diffuser]

Need i said more?

https://twitter.com/LupionGP/status/846031997185282050

Yep ...don't need to put a HP number to it.... Its ALOT

[JuanjoTS]

It's not so easy to introduce new engines so quickly.

McHonda's maximum error was to announce his union from 0, McLaren should have followed up with MER these past 2 years by secretly providing Honda chassis to test their engines. After this great mistake, what is important is that they put a lot of money and increase the speed of evolution with risk of a test kilometers

[63l8qrrfy6]

If you can reduce the mass or increase the stiffness you can cause a resonance shift, there are also hemholtz chambers that can cancel out the resonance. Wouldn't it be awesome if Honda can make the pre-chamber also be a hemholtz chamber so that it reduces harmonic vibrations and increases mixing turbulence at the same time?

Crevices knacker combustion...
My point was 10% increase in stiffness gives you less than 5% increase in frequency - that is if you somehow do it without adding any mass at all. Rule of thumb is 1.2 separation margin. Practically you're better off scrapping the engine and starting from scratch - just like Cosworth did with their inline 4 turbo.

How do they do it with a pre-chamber then? Ideally would you want to have the pre-chamber be partially formed by the piston and partially by the combustion chamber to minimize crevices? Honda's original CVCC was exactly a crevice with an auxillary intake valve. Also maybe that 5% is all that's needed to move the resonance from a frequency that damages things to a frequency where things can tolerate it.

Also scrapping the engine is probably going a bit far, cylinder head most likely yes, pistons, crank, sure, but I doubt the block itself needs any scrapping.

My reasoning that 5% may do the trick comes from this video
https://youtu.be/L5fVFA2sWt4

Ah yes ! the resonant frequency of a pipe can be changed easily - it's only given by the local speed of sound divided by its length, however:

A while ago we were trying to measure combustion pressures (200+ bar) in a petrol engine with a fairly standard DI setup. As the sensor could not cope with the high in-cylinder temperatures we installed it in a small cavity a few mm away from the combustion face and ended up with a high frequency content we could not really explain in all instrumented cylinders. What caused a lot of head-scratching was the fact that the laser torsional vibrometer was not picking up that frequency at all, so whatever it was it was not being passed on to the piston.

Quite embarrassingly it was just the pressure wave reflecting off the open end of the sensor cavity. The point is I am now fairly sure these 'local' excitations are not passed on to the piston even though the amplitudes were quite high.

Anyway, as we were now convinced that the frequency we were seeing was not important we filtered it out expecting to end up with a very smooth trace - just as predicted by the combustion guys. Wrong again - we still had fairly large amplitudes at a different frequency and these were actually being picked up by the vibrometer and were being very consistent cylinder to cylinder. We even placed the sensors very close to the combustion face knowing they'll get mangled in minutes just to confirm they weren't reading bollocks. I still have no clue what is causing those frequencies but they have existed to a certain extent on every engine we've ever instrumented, is just that in the past we would just average the traces over multiple cylinders and over several cycles and loose that content as it was artificially smoothed out.

As injectors became more advanced and variability decreased, the high frequency content became more 'repeatable' to the point we had to consider it for forced vibration calculations but I was never really given a concrete explanation on what was causing it - let alone how to alter it. Combustion simulations still produce pressure traces smooth as a baby's bum which means that designing the whole engine before you have single cylinder testing data is simply hopeless.

[diffuser]

So we still have 'reliability upgrades' right, with the other teams ability to veto (Mutually Assured Destruction if they do of course..) without dipping into the 4 PU supply. FIA will let you essentially rebuild the engine with new parts if they are for reliability which should be easy enough for Honda to prove. They need to be working and aiming FAR higher than anyone else could imagine.. shoot for 60% efficiency by years end.. just put it out there already stop trying to catch up and put a marker out there for others to look at.

No.

[JuanjoTS]

It's not so easy to introduce new engines so quickly.

Is tremendously complicated and very difficult, but it is the path they chose.

[63l8qrrfy6]

That coupled with the 100% torque demand that goes along with most up shifts coupled by an immediate drop in revs. Downshifts requiring far less torque demand or even negative.

More precise control of the other systems (turbine/compressor/K/H) may not be quite to what is required for combustion stability during abrupt changes in operating conditions.

Not quite.
On a downshift you increase the engine speed by a few thousand rpm in about 0.1 sec.
That is a massive angular acceleration.
Torque is then given by the whole engine inertia times that angular acceleration. That's a big number regardless what sign it has ! (It is positive)

[godlameroso]

Also it just occurred to me that very high frequency vibrations can help vaporize gasoline to an extent.

[dren]

That coupled with the 100% torque demand that goes along with most up shifts coupled by an immediate drop in revs. Downshifts requiring far less torque demand or even negative.

More precise control of the other systems (turbine/compressor/K/H) may not be quite to what is required for combustion stability during abrupt changes in operating conditions.

Not quite.
On a downshift you increase the engine speed by a few thousand rpm in about 0.1 sec.
That is a massive angular acceleration.
Torque is then given by the whole engine inertia times that angular acceleration. That's a big number regardless what sign it has ! (It is positive)

No, I was referring to the combustion side, torque demand at the pedal/brake. I'm saying maybe it is an issue of not being able to maintain combustion stability on the upshift, when torque (combustion) is demanded as opposed to braking when downshifting.

If it was a matter of forces between ice/trans, wouldn't you see if on both up and down shifts?