Honda Power Unit Hardware & Software

[63l8qrrfy6]

I think there is some misunderstanding here. The vibration problems Honda has result out of the new crankshaft design or the firing order. Atleast that's what I think. The potential for harmonic vibrations rsulting out of bigger combustion vibrations are low, probably about Zero

The problem, why they (atleast it seems like that) didn't use TJI, is because of the faulty head design. They need to fix their rumoured problems with the valves and so on...

Vibration fix is relatively easy, it's jsut making the engine a big heavier. How long will the fix for the head take? Probably less than 2 months, it should be ready for spain.

The cleaner and less raspier Sound of the PU indicates, that no TJI has been used. I know it's not much and things like that can't be really seen in a "audio analysis". But if you hear closely, you can really somehow figure out that combustion is running "smoother".

Hey Glenny,

Please don't take this the wrong way but you are very wrong regarding several aspects:

1) The combustion is the primary source of excitation in the engine. Your statement regarding the improbability of combustion 'fluctuations' to cause harmonic vibrations is fundamentally wrong. In itself the pressure trace is a vibration - therefore any major harmonic components of it have the potential to cause vibrations. Furthermore, a well controlled combustion event will always provide repeatable high frequency content as opposed to chaotic combustion (knock, but not limited to) making it more likely to excite a particular mode.

If you are still not convinced you can find measured cylinder pressure traces online, do an FFT on them and look at the order higher than 1.

2) Torsional vibration problems are not easy to solve at all. Really, if a torsional issue has not been identified at the design stage it will be incurable without major redesigns. An increase in stiffness (k) is most likely accompanied by an increase in mass (m). As frequency goes up with the square root of (k/m) the amount you can shift your resonance by is negligible. Sure, you can manage the vibration with dampers or isolate it with compliant elements but really this is just a compromise - both these elements are a nightmare to package particularly when used as an afterthought. Dampers have to dissipate energy as heat which has to be somehow managed and soft couplings have notoriously low torque capabilities.

3) Anyone thinking they can make anything of the engine sound by just listening is simply disillusioned. That exhaust sound is dominated by the 1.5th order and distorted by exhaust tuning frequency and turbo blade passing frequency. Maybe with decent software you can filter out these frequencies (primary firing is easy, exhaust is probably tuned around 10k rpm and turbo likely has an odd number of blades if a twin entry turbine is used) but even so I reckon you would struggle to make sense of what's left.

But being able to tell whether or not it has TJI by just listening? Really ??!!

[JuanjoTS]

I will try to explain in my opinion the faults of the Honda engine.
Basically its error is similar to the one of the turbo, smaller but functioning at high revolutions.

They have generated a combustion chamber with cylinders of large diameter but with little length, which means that the maximum torque is delivered at high revolutions, that increases the consumption, have not taken into account the limit of 105kg per gp, by reducing The revolutions per minute to conserve fuel, get the engine of its optimum revolutions to have the greatest torque, leaving the car in an area where it does not push what it should

The fia limit is 15,000 rpm, MER and FER work between 10,500 rpm and 11,700 rpm, while Honda works between 11,000 rpm and 12,500 rpm, which translates into higher consumption, the tank does not allow to roll all the gp in that Level of revolutions, forces them to lower rpm until the engine reaches its optimum torque.

[godlameroso]

I think there is some misunderstanding here. The vibration problems Honda has result out of the new crankshaft design or the firing order. Atleast that's what I think. The potential for harmonic vibrations rsulting out of bigger combustion vibrations are low, probably about Zero

The problem, why they (atleast it seems like that) didn't use TJI, is because of the faulty head design. They need to fix their rumoured problems with the valves and so on...

Vibration fix is relatively easy, it's jsut making the engine a big heavier. How long will the fix for the head take? Probably less than 2 months, it should be ready for spain.

The cleaner and less raspier Sound of the PU indicates, that no TJI has been used. I know it's not much and things like that can't be really seen in a "audio analysis". But if you hear closely, you can really somehow figure out that combustion is running "smoother".

Hey Glenny,

Please don't take this the wrong way but you are very wrong regarding several aspects:

1) The combustion is the primary source of excitation in the engine. Your statement regarding the improbability of combustion 'fluctuations' to cause harmonic vibrations is fundamentally wrong. In itself the pressure trace is a vibration - therefore any major harmonic components of it have the potential to cause vibrations. Furthermore, a well controlled combustion event will always provide repeatable high frequency content as opposed to chaotic combustion (knock, but not limited to) making it more likely to excite a particular mode.

If you are still not convinced you can find measured cylinder pressure traces online, do an FFT on them and look at the order higher than 1.

2) Torsional vibration problems are not easy to solve at all. Really, if a torsional issue has not been identified at the design stage it will be incurable without major redesigns. An increase in stiffness (k) is most likely accompanied by an increase in mass (m). As frequency goes up with the square root of (k/m) the amount you can shift your resonance by is negligible. Sure, you can manage the vibration with dampers or isolate it with compliant elements but really this is just a compromise - both these elements are a nightmare to package particularly when used as an afterthought. Dampers have to dissipate energy as heat which has to be somehow managed and soft couplings have notoriously low torque capabilities.

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?

[ENGINE TUNER]

They have generated a combustion chamber with cylinders of large diameter but with little length, which means that the maximum torque is delivered at high revolutions, that increases the consumption, have not taken into account the limit of 105kg per gp, by reducing The revolutions per minute to conserve fuel, get the engine of its optimum revolutions to have the greatest torque, leaving the car in an area where it does not push what it should

You are completely mistaken

The fuel consumption does not change with increasing RPM's in this fuel flow restricted formula. These engines use the same amount of fuel whether they are at 10.5k rpm or at 15k rpm. The main determining factor of fuel usage is time on throttle which is dependent on power, traction and drag.

Fuel flow remains constant after 10.5k rpm, the boost decreases and thus the energy that the MGUH is able to recover also decreases.

Also bore size is limited in the regulations and all the engines are running pretty much the same bore size and thus stroke.

[JuanjoTS]

A point that I do not understand, is the error for 3 years of putting an eighth gear excessively long, practically useless.

They have generated a combustion chamber with cylinders of large diameter but with little length, which means that the maximum torque is delivered at high revolutions, that increases the consumption, have not taken into account the limit of 105kg per gp, by reducing The revolutions per minute to conserve fuel, get the engine of its optimum revolutions to have the greatest torque, leaving the car in an area where it does not push what it should

You are completely mistaken

The fuel consumption does not change with increasing RPM's in this fuel flow restricted formula. These engines use the same amount of fuel whether they are at 10.5k rpm or at 15k rpm. The main determining factor of fuel usage is time on throttle which is dependent on power, traction and drag.

Fuel flow remains constant after 10.5k rpm, the boost decreases and thus the energy that the MGUH is able to recover also decreases.

Also bore size is limited in the regulations and all the engines are running pretty much the same bore size and thus stroke.

More explosions equals more consumption, is a constant.

[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.

[ENGINE TUNER]

They have generated a combustion chamber with cylinders of large diameter but with little length, which means that the maximum torque is delivered at high revolutions, that increases the consumption, have not taken into account the limit of 105kg per gp, by reducing The revolutions per minute to conserve fuel, get the engine of its optimum revolutions to have the greatest torque, leaving the car in an area where it does not push what it should

You are completely mistaken

The fuel consumption does not change with increasing RPM's in this fuel flow restricted formula. These engines use the same amount of fuel whether they are at 10.5k rpm or at 15k rpm. The main determining factor of fuel usage is time on throttle which is dependent on power, traction and drag.

Fuel flow remains constant after 10.5k rpm, the boost decreases and thus the energy that the MGUH is able to recover also decreases.

Also bore size is limited in the regulations and all the engines are running pretty much the same bore size and thus stroke.

More explosions equals more consumption, is a constant.

You are Wrong.

More explosions yes, but smaller explosions(using less fuel(and thus air/boost) per explosion). The fuel rate is 100kg/hr, that does not change relative to engine speed, that is the hard and fast regulation.

If you run these engines on the dyno at 10.5k rpm or 15k rpm they will both run out of fuel in 1 hour... that is the rule.

[godlameroso]

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

[JuanjoTS]

All cylinders have the same volumetric capacity to obtain the 1.6 cc, change the diameter of the cylinder and the stroke, bigger diameter smaller stroke greater number of explosions (rpm) greater consumption. Anyway consider it my opinion, I do not want to enter into discussions.

[ENGINE TUNER]

If you do not want to enter discussions why are you on a discussion board posting incorrect things?

The size of the cylinder is less significant in a turbo charged engine. If it is running at 3 bars of boost it is putting 3 times as much air into the same cylinder and thus approximately 3 times as much fuel(except in this formula the fuel rate is fixed at 100kg/hr).

[godlameroso]

Well bore and stroke are pretty much defined in the regulations but what isn't defined is the rod ratio. In other words are they using really long throws and short rods, or long rods and short throws?

[JuanjoTS]

Honda falls into the trap you mention, believes you can manufacture a motor so elastic, that allows you to work at rpm that respects the 105kg per gp and can work a few laps as close to 15,000rpm to achieve over x time a power higher than Of the rest of its rivals. Personal opinion.

[JuanjoTS]

All cylinders have the same volumetric capacity to obtain the 1.6 cc, change the diameter of the cylinder and the stroke, bigger diameter smaller stroke greater number of explosions (rpm) greater consumption. Anyway consider it my opinion, I do not want to enter into discussions.

If you do not want to enter discussions why are you on a discussion board posting incorrect things?

The size of the cylinder is less significant in a turbo charged engine. If it is running at 3 bars of boost it is putting 3 times as much air into the same cylinder and thus approximately 3 times as much fuel(except in this formula the fuel rate is fixed at 100kg/hr).

Everyone is looking to get 1.6 cc with 6 cylinders, understand I do not want to get into arguments like ... I do not want to make him look ridiculous.

Well bore and stroke are pretty much defined in the regulations but what isn't defined is the rod ratio. In other words are they using really long throws and short rods, or long rods and short throws?

Has hit the nail, bars too short.

[godlameroso]

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

[JuanjoTS]

All cylinders have the same volumetric capacity to obtain the 1.6 cc, change the diameter of the cylinder and the stroke, bigger diameter smaller stroke greater number of explosions (rpm) greater consumption. Anyway consider it my opinion, I do not want to enter into discussions.

If you do not want to enter discussions why are you on a discussion board posting incorrect things?

The size of the cylinder is less significant in a turbo charged engine. If it is running at 3 bars of boost it is putting 3 times as much air into the same cylinder and thus approximately 3 times as much fuel(except in this formula the fuel rate is fixed at 100kg/hr).

A race lasts an hour and a half, if you use the maximum allowed of 100kg / h you do not arrive at the checkered flag. The secret is to get a motor so elastic that is able to work at rpm that respect the 105kg per gp and get a few laps as close as possible to the consumption limit, 100kg / h.

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