Honda Power Unit Hardware & Software

[JuanjoTS]

Is it possible that these extreme vibrations are due to the (supposed) unorthodox sequence of cylinder firing?

I don't know nothing about cylinder order and how it affects the engine, just got the bit that supposedly Honda are using a "rare" firing order... how possible that partly this order is responsible for these unexpected vibrations?

Can you indicate the source of your information?

Hasegawa;

It might hurt more because China has a longer straight," Hasegawa said. "So that [straight] will be very painful I think; that's why we are trying to introduce something more but we can't promise about that."
"I have no idols. I admire work, dedication & competence."

The most affordable to change in two weeks would be the crankshaft, with the same measures but a more rigid material.

[godlameroso]

Two types of pre-chamber spark plugs were sampled, i.e. a 3kΩ resistor pre-chamber spark plug and a non-resistor spark plug. The resistor pre-chamber spark plug has four injection orifices on the front end surface, while the non-resistor spark plug has three slightly smaller holes on the front end surface and three tiny holes on the side cylindrical surface for a better scavenging effect. A NGK resistor spark plug (5 kΩ) with a v-groove center electrode and a J-type ground electrode was also tested to benchmark the pre-chamber spark plugs.

http://www.apyeco.com/images/spark.JPG
Figure 1 gives the ignition flame images at 5ms after spark initiation for premixed methane-air mixtures with an excess air ratio of 1.6. It is clear that the ignition flame propagation for the two pre-chamber spark plugs was faster than the NGK spark plug. The non-resistor pre-chamber spark plug produced much faster flame jet due to the increased spark energy. The wrinkled flame front accelerated the combustion speed.
In the other experiment, we compared the ignition processes for the MXTL resistor pre-chamber spark plug, the Tongxin’s iridium fine electrode spark plug (EIX-BKR6 11) and thick electrode spark plug (E-BKR6). The excess air ratio of methane-air mixture was set at stoichiometric. Figure 2 shows the flame



images at 2ms and 4ms after spark initiation. It can be seen that the iridium fine electrode spark plug spark plug can produce a faster flame kernel growth than the thick electrode spark plug. The flame front
of the MXTL pre-chamber spark plug appears later than the other spark plugs, but the post-ignition flame propagation was accelerated due to the turbulent flame jet effect.
The ignition performance of non-resistor pre-chamber spark plug can be further enhanced via capacitor discharge. Figure 3 gives the flame images with enhanced capacitor discharge at excess air
ratio of 1.0, 1.2 and 1.4 respectively. It can be seen that the capacitor discharge significantly accelerated the flame jet velocity; hence it increased the ignition flame propagation especially prominent at lean mixtures.
http://www.apyeco.com/images/mxtl.JPG

http://www.sangwonenc.com/eng/business/ ... mg_011.jpg

How are these prechamber spark plugs different to TJI? Is it just the flame length and duration are longer? Or do they offer better control?

Thanks. You know what that reminds me of? Those spark plug spacer/anti foulers, only with holes drilled along the edge. Hmm I may try that on my moped and see if it works.

[dren]

This is an excellent read about a TJI study done at Purdue University: http://web.ics.purdue.edu/~lqiao/Public ... bility.pdf

godlameroso, check out page 7.

The study uses a prechamber that is 1% of total combustion chamber volume. The prechamber mix is near stoic, the main chamber is lean. I assume this is how the systems would work in the F1 ICEs as well. Different nozzle styles were used. Combustion delay is measured, too. I know that's been discussed a few times on here.

The leaner you run the main chamber, the more unstable the combustion becomes. This might be why Honda ran a single cylinder just fine, but ran into issues when dealing with intake and exhaust pulses from two extra cylinders.

[JuanjoTS]

I'm a mechanic, I get my hands dirty for a living, I only use commonly used words, and I'm just trying to understand where you're coming from. Pm me we can discuss in Spanish if you want.

I mean most coil packs in modern cars send as many as 120,000 volts from the coil to the spark plug. And the spark on conventional plugs doesn't heat the plug up very much. Like I said it's possible but my dumb mechanic self is scratching my head trying to figure out how you get a spark plug to work like a diesel glow plug. Carbon electrode?

Instead of using the spark plug for the ignition of the mixture they use it as a heater inside the pre-chamber combustion, the direct ignition by spark is too focused at a certain point and has a very short spark-carrying durability, this makes That the mixture does not burn efficiently. In the pre-combustion chamber try to get between 270-300c ° so that just in time PSI autoignition the mixture in the pre-combustion chamber and this in turn ignites the mixture of the main chamber of the cylinder. This achieves greater efficiency in combustion, generating more power with less fuel, otto / diesel cycle. As they do exactly do not know, but I know that the purpose is for the pre-combustion chamber to reach between 270-300c ° to achieve the above.

[JuanjoTS]

I don't think these ICEs are dieseling, or at least designed to operate that way. The idea is to ignite extremely lean mixtures, reliably.

Tji technology is an otto / diesel cycle, Malhe look for a way to get the thermal efficiency of diesel cars in street cars of gas, from there it was coupled to the F1.

[cobart]

Mahle use spark plugs to ignite rich mixture in prechamber.

"...TJI system is capable of stable operation with extremely low ignition energies (10mJ)
as compared to conventional spark ignition system which required a minimum
energy of 40mJ at identical operating conditions."
Shah, A. (2015). Improving the Efficiency of Gas Engines using Pre-chamber Ignition Lund University
http://portal.research.lu.se/portal/fil ... 228492.pdf

Mahle Ignition concept is continuation of L.A.Goossak patents "....A conceptually new way of operating a pre-chamber engine was developed in 1966,
when a Russian scientist called Goossak Lev Abramovich (L. A. Gussak), proposed
[31] the use of a very rich mixture (λ = 0.4-0.7) in the pre-chamber to produce a
low temperature torch of incomplete combustion products (not a flame) containing
chemically active species/atoms like CO, H2, aldehyde and peroxide. This concept
was called ’Lavinia Aktyvatsia Gorenia’ in Russian and hence is generally referred
to as the LAG-Ignition process " Shah, A. (2015).

[dren]

Why would you rely on compression ignition in the prechamber when you can use a spark plug? Wouldn't you want to control ignition timing?

[restless]

Is it possible that these extreme vibrations are due to the (supposed) unorthodox sequence of cylinder firing?

I don't know nothing about cylinder order and how it affects the engine, just got the bit that supposedly Honda are using a "rare" firing order... how possible that partly this order is responsible for these unexpected vibrations?

Can you indicate the source of your information?

Look at viewtopic.php?f=4&t=18874&hilit=wazari& ... 75#p674145
and discussion after that

[restless]

Why would you rely on compression ignition in the prechamber when you can use a spark plug? Wouldn't you want to control ignition timing?

I guess with compression ignition one will get bigger/wider flame front - the whole prechamber will ignite?

[godlameroso]

This is an excellent read about a TJI study done at Purdue University: http://web.ics.purdue.edu/~lqiao/Public ... bility.pdf

godlameroso, check out page 7.

The study uses a prechamber that is 1% of total combustion chamber volume. The prechamber mix is near stoic, the main chamber is lean. I assume this is how the systems would work in the F1 ICEs as well. Different nozzle styles were used. Combustion delay is measured, too. I know that's been discussed a few times on here.

The leaner you run the main chamber, the more unstable the combustion becomes. This might be why Honda ran a single cylinder just fine, but ran into issues when dealing with intake and exhaust pulses from two extra cylinders.

Thanks for that.

I found this bit very interesting

Unstable flame propagation due to strong presence of combustion
instability was observed at ultra-lean conditions, ϕ ranging from 0.22
to 0.4. This, however, was not observed for near-stoichiometric
main-chamber mixtures in our previous study. The instability
becomes more and more severe as the fuel/air equivalence ratio of the
main chamber mixture reduces at lean-burn conditions. Oscillating
flames were observed from both high-speed Schlieren imaging as
well as oscillating pressure data. Reduction in stability of flame
propagation limit is a major setback that not only affects performance
via unstable combustion dynamics but also affect the structural
integrity of the engine.Controlling such instability, active or passive,
requires adequate knowledge about the fundamental mechanism such
as different types of instability modes, perturbation energy, and
frequencies.

[Tommy Cookers]

[quote=JuanjoTS post_id=688966 time=1491391156 user_id=34918]
[quote=restless post_id=688929 time=1491375278 user_id=35673]
Is it possible that these extreme vibrations are due to the (supposed) unorthodox sequence of cylinder firing?
I don't know nothing about cylinder order and how it affects the engine, just got the bit that supposedly Honda are using a "rare" firing order... how possible that partly this order is responsible for these unexpected vibrations?[/quote]
Can you indicate the source of your information?
The most affordable to change in two weeks would be the crankshaft, with the same measures but a more rigid material.[/quote]

I say there's only 2 firing orders possible
either each bank going a, b, c when the other bank is going a, b, c or one bank going a, b, c when the other goes a, c, b

isn't the crankshaft material limited by the rules to iron or steel ?
some alloy with a very high tungsten content could have almost double the elastic modulus of steel but is correspondingly denser
so the bare crankshaft would have about the same natural frequency
but the reciprocating parts masses are unchanged, so there would be a useful benefit to the natural frequency of the assembly
this and the greater stiffness/inertia ratio of the assembly might well be helpful in reducing displacement and damaging effects

if the rules allowed this

[PlatinumZealot]

But if injector is in the pre-chamber ( i think it is in that) how it can inject it to the main chamber and how it can just keep second injection in pre-chamber. İf it were not direct injection or double injector per cylinder it is easier.
Also I want to learn that isn't mixture in the main chamber enters to the pre-chamber during compression and cant it be ignited to ignite main chamber?

I thought there were two injectors - a direct injector for the lean mix in the cylinder and a separate injector for the pre-chamber.

My theory since 2014 is that two injectors are used, and the injector inside the pre-chamber is not considered a direct injector.

5.10.2 There may only be one direct injector per cylinder and no injectors are permitted upstream of
the intake valves or downstream of the exhaust valves. Only approved parts may be used and
the list of parts approved by the FIA, and the approval procedure, may be found in the
Appendix to the Technical Regulations.

There is no injector in the pre-chamber, the filling of the pre-chamber occurs at the time of compression of the main chamber of the cylinder.

Calling it pre-camera can lead to errors, if we talk about admission would be sub-camera, since its filling is later than the main camera,If we talk about explosion it's pre-chamber, the explosion occurs prior to that of the main camera (Is used as a super spark plug )

Ideally, it should be called a pre-combustion chamber to avoid misunderstandings.

That is easy to say... proof?

[PlatinumZealot]

I don't think these ICEs are dieseling, or at least designed to operate that way. The idea is to ignite extremely lean mixtures, reliably.

Tji technology is an otto / diesel cycle, Malhe look for a way to get the thermal efficiency of diesel cars in street cars of gas, from there it was coupled to the F1.

Nope completely wrong. TJI is on the opposite spectrum of diesel. TJI induces very rapid ignition. Even more rapid than spark. Diesel flame speeds is the lowest. And the primary reason why diesel are rpm limited.

[FW17]

There were some rumour articles which mentioned that Honda TJI project started only in May 16

That is a whole year after the TJI rumours started in the forums. Any reason for the delay? Man power resources?

[godlameroso]

Is it possible that these extreme vibrations are due to the (supposed) unorthodox sequence of cylinder firing?
I don't know nothing about cylinder order and how it affects the engine, just got the bit that supposedly Honda are using a "rare" firing order... how possible that partly this order is responsible for these unexpected vibrations?

Can you indicate the source of your information?
The most affordable to change in two weeks would be the crankshaft, with the same measures but a more rigid material.

I say there's only 2 firing orders possible
either each bank going a, b, c when the other bank is going a, b, c or one bank going a, b, c when the other goes a, c, b

isn't the crankshaft material limited by the rules to iron or steel ?
some alloy with a very high tungsten content could have almost double the elastic modulus of steel but is correspondingly denser
so the bare crankshaft would have about the same natural frequency
but the reciprocating parts masses are unchanged, so there would be a useful benefit to the natural frequency of the assembly
this and the greater stiffness/inertia ratio of the assembly might well be helpful in reducing displacement and damaging effects

if the rules allowed this

5.17.4 Crankshafts must be manufactured from an iron based alloy(see 5.15.1).
No welding is permitted between the front and rear main bearing journals.
No material with a density exceeding 18,400 kg/m3 may be assembled to the crankshaft.
These parts assembled to the crankshaft may be manufactured in a Tungsten based material.

5.15.1 X Based Alloy (e.g. Ni based alloy) – X must be the most abundant element in the alloy on a %w/w basis. The minimum possible weight percent of the element X must always be greater than the maximum possible of each of the other individual elements present in the alloy.

Steel is mostly Iron, and only has a few percentages of things like chromium, cobalt, carbon, etc, the point being you don't need to radically change the composition of an alloy to radically change it's properties. The regulations give you a lot of leeway as far as alloy composition.