Honda Power Unit Hardware & Software

[trinidefender]

And even then, moving the engine forwards and extending the transmission still gives you better packaging at the rear because the exhaust manifold blockage has been shifted forwards.

The beauty of having a works partnership, the two partners build their components around each other. There's no doubt the packaging of the Honda engine allows a very tight bodywork, they have not made a compromise on the tank volume.

Unsubstantiated comment that holds no more weight than anyone elses. You or I or anyone else simply doesn't know.

That's like the argument that some people make that designers of midfield cars engineer their cars to be better in traffic than free air yet every time a technical director or other person has been asked this question it has been rubbished with answer invariably being no, they design their cars to be the fastest outright in free air.

Referencing the late race safety cars. Safety cars save fuel which adds weight to the argument that it might be beneficial to build a car with a smaller tank. If a driver is having to severely fuel save due to their car being underfuelled then a safety car is a blessing.
Lastly for a race where we take your scenario and build a car with a big tank and fill it we are then forced to drive around with extra fuel slowing us down if we can't use it.

[godlameroso]

And even then, moving the engine forwards and extending the transmission still gives you better packaging at the rear because the exhaust manifold blockage has been shifted forwards.

The beauty of having a works partnership, the two partners build their components around each other. There's no doubt the packaging of the Honda engine allows a very tight bodywork, they have not made a compromise on the tank volume.

Unsubstantiated comment that holds no more weight than anyone elses. You or I or anyone else simply doesn't know.

That's like the argument that some people make that designers of midfield cars engineer their cars to be better in traffic than free air yet every time a technical director or other person has been asked this question it has been rubbished with answer invariably being no, they design their cars to be the fastest outright in free air.

Referencing the late race safety cars. Safety cars save fuel which adds weight to the argument that it might be beneficial to build a car with a smaller tank. If a driver is having to severely fuel save due to their car being underfuelled then a safety car is a blessing.
Lastly for a race where we take your scenario and build a car with a big tank and fill it we are then forced to drive around with extra fuel slowing us down if we can't use it.

But you know that they build their fuel tanks as small as possible because the few tenths from being lighter and few cc of free space will make all the difference? What happens when you go to a fuel thirsty track, do you just accept that you'll be struggling and having to fuel save?

[PhillipM]

You fuel save at every track you can, it's faster. Even with these engines.

[cheeRS]

You fuel save at every track you can, it's faster. Even with these engines.

Exactly. At first (at least to me) it seemed counterintuitive to save fuel, or to fuel much less than allowed. But it's a lot like the tires for the last 10 years or so. Unfortunately for us fans and drivers, the fastest laps possible on a given set of tires is rarely the most efficient when the whole race is considered.

In a nutshell, PU efficiency increases from 2014 until now (per manufacturer), tire use (and power demand/traction), PU life requirements (only 3 this year!), max fuel flow, and larger fuel allotments (100kg-->110kg) have in effect all pushed fuel tank capacity down reqs down along with fueling levels.

Even if you could have a strategy where you could make use of all 110kg of fuel and be the fastest, the PU per season requirements mean that it's likely too risky to do so. A lot less risky to say you're going to design a 90kg capacity fuel tank, fill between 80-90kg per race, and never run the PU above 95% for extended periods unless it has already passed the 7-8 race mark.

[PlatinumZealot]

A bucket lifter type valvetrain is peak velocity limited. To get more area under the lift curve, the bucket has to be larger in diameter.

A finger follower is a rocker and has its own rocker ratio, which multiplies the lobe profile. Valvetrains can be much more compact in this configuration with the same or better performance.

A Desmo. type valvetrain was a solution to poor valve spring technology at the time. That hasn’t been an issue in 20 years, short of being rpm limited (still, 600cc sportbikes rev to 15k with valvesprings and with full warranties to boot! But tiny / light valves). Indy Car and NASCAR money paved the way for a big leap in valve spring technology in the mid 2000s.

F1 and MotoGP have pneumatic “springs” which allows you to not be constrained by a wire spring design.

If the cams are inboard, then the followers would also be inboard which means the angle between the valves would increase. However Honda says they narrowed the valve angle leading to a flatter pent roof shape. You cannot do that with the camshafts where they are(near the center/inboard) because then you're forced to have the rockers outboard. If the cams were outboard then you could run the followers under the cam and have the valves closer together with a flatter pent roof.

However for 2021 the cams are near the center line, as are the valve angles, thus you have no room for rockers/followers.

https://i.ebayimg.com/images/g/R4EAAOSw ... s-l400.jpg

Here you see the cams, as indicated by the cam caps, are inboard of the rockers which are again, inboard of the valves. This limits the pent roof shape and the angle of the valves.

With this arrangement reversed you could narrow the valve angle.

That can be solved with chaning the shape of the rocker though.

Otherwise you could go direct yes.

I am trying to remember if F1 ever changed from direct cam on bucket though? Did they?

The closer spaced cams are used on Mercedes too. So im wondering why it wasnt used in Honda from the get go. Probably combustion concept was different.

You decide


Is Honda more Narrow? Maybe a couple mm. The Honda cams seem to be a few mm lower too but not much. So less space for valve actuation. I think this valves could be cam on
Bucket. Some really small buckets.

[JordanMugen]

And even then, moving the engine forwards and extending the transmission still gives you better packaging at the rear because the exhaust manifold blockage has been shifted forwards.

The beauty of having a works partnership, the two partners build their components around each other. There's no doubt the packaging of the Honda engine allows a very tight bodywork, they have not made a compromise on the tank volume.

Would you say continuing with this highly advanced Honda RA621H is more advantageous for Red Bull than adopting the Renault 2022 power unit that has yet to be released?

Unsubstantiated comment that holds no more weight than anyone elses. You or I or anyone else simply doesn't know.

How so? The packaging of the Honda seems to be clearly superior to that of the Renault, at least in 2021 specification. Allowing sidepod cooling air to flow through the structural part of the engine (due to the new open design), allows (for instance) for more compact sidepods.

I don't see how Red Bull would obtain any short term benefits from adopting Renault power units.

https://www.speednik.com/wp-content/blo ... merf12.jpg

Good spot to note that Mercedes already had a similar valvetrain design. Bravo!

[trinidefender]

And even then, moving the engine forwards and extending the transmission still gives you better packaging at the rear because the exhaust manifold blockage has been shifted forwards.

The beauty of having a works partnership, the two partners build their components around each other. There's no doubt the packaging of the Honda engine allows a very tight bodywork, they have not made a compromise on the tank volume.

Would you say continuing with this highly advanced Honda RA621H is more advantageous for Red Bull than adopting the Renault 2022 power unit that has yet to be released?

Unsubstantiated comment that holds no more weight than anyone elses. You or I or anyone else simply doesn't know.

How so? The packaging of the Honda seems to be clearly superior to that of the Renault, at least in 2021 specification. Allowing sidepod cooling air to flow through the structural part of the engine (due to the new open design), allows (for instance) for more compact sidepods.

I don't see how Red Bull would obtain any short term benefits from adopting Renault power units.

https://www.speednik.com/wp-content/blo ... merf12.jpg

Good spot to note that Mercedes already had a similar valvetrain design. Bravo!

The unsubstantiated but was referring to the part where they were saying that the fuel tank volume isn't being compromised. I wasn't saying that the Honda PU doesn't have good packaging.

[Hoffman900]

Performance in what sense?

I'd reckon ~ somewhere between 13 and 14 degrees. It's not hard to have small included angles with SOHC since the rockers can be close to the cam which is exactly on the centerline of the cylinder head. The CBR1000 RR has outboard camshafts.

The bucket diameter is what dictates maximum lobe velocity. They’re just direct acting flat tappet designs.

The peak valve lift and and lift area (under the curve) would be severely hampered using this design, especially since you still have to fit the injection unit in between plus the spacing between the adjacent valves.

Is that what Honda uses in the F1?

As a somewhat related question, who were the first to use roller lifters?

Roller lifters in what? Roller lifters go back to prewar era. Remember, rollers are also acceleration limited (and heavy)

Formula One (that I’ve seen) and any other high output racing engine in the last twenty years uses finger followers. It creates a very stiff and compact valvetrain but allows you lobe multiplication via a rocker arm.

This is one thing a pushrod engine has a huge advantage of over an OHC bucket follower type valvetrain, is the ability to use pretty big rocker ratios. This is how NASCAR runs 1” of valve lift (and through good engineering, they last about 1500 miles). Those applications are valve spring limited in terms of valve opening area.

I see finger followers the best of both worlds.

Since bucket followers are velocity limited, a “very tiny bucket” would also have very tiny valve lift and very little area under the curve.

[maxxer]

You fuel save at every track you can, it's faster. Even with these engines.

Exactly. At first (at least to me) it seemed counterintuitive to save fuel, or to fuel much less than allowed. But it's a lot like the tires for the last 10 years or so. Unfortunately for us fans and drivers, the fastest laps possible on a given set of tires is rarely the most efficient when the whole race is considered.

In a nutshell, PU efficiency increases from 2014 until now (per manufacturer), tire use (and power demand/traction), PU life requirements (only 3 this year!), max fuel flow, and larger fuel allotments (100kg-->110kg) have in effect all pushed fuel tank capacity down reqs down along with fueling levels.

Even if you could have a strategy where you could make use of all 110kg of fuel and be the fastest, the PU per season requirements mean that it's likely too risky to do so. A lot less risky to say you're going to design a 90kg capacity fuel tank, fill between 80-90kg per race, and never run the PU above 95% for extended periods unless it has already passed the 7-8 race mark.

Still they make more PU's anyway and have the cost of the tooling so this rule i have always found a bit to harsh
Now we will get races where they will run with the older pu because its not so demanding?

[gruntguru]

That's assuming a 2.3% difference in mass is worth 23hp, but what if that 2.3% extra mass gives you an extra 50hp for however long it takes you to burn that amount? Then you'd have a net 27hp gain over someone who only fueled just enough to finish. That 50hp can be from not having to turn down the engine, less lift and coast, more electrical energy harvesting.

At the end of the day if you're going to burn most of the fuel, you'll be just as fast as the guys who only fueled to make the race, but you'll have more options. If you have a pace advantage it opens even more options.

Wouldn't the extra weight, and harsher braking/accelerating just destroy the tyres anyway?

No, not really, destroying or preserving tires is mostly due to driving style. 2.3% extra mass is nothing compared to the aero loads these tires already see. Pirelli deliberately designs tires that are only good for 150km max. Most road tires take 500km just to break in.

The problem with extra mass is not the downward force on the tyres. Its the added lateral and longitudinal force required to brake, accelerate and corner at the same G's - especially in a high DF car.

eg cornering at 5g in a 1000 kg car with tyre friction coefficient of 1.0 requires 5000 kg of lateral force and 4000 kg of aero. Increase the mass by 10% to 1100 kg and lateral force becomes 5500 and required aero becomes 4400. (and drag will increase by a similar % too)

(values chosen for calculation simplicity and not to reflect F1 values)

[gruntguru]

If I remember correctly 10kg is estimated to be about 0.1 seconds lap time but don't quote me on that.

Secondly and also something else to consider. If they design a car with a tank that can only hold 90kg of fuel Vs 110kg then there is a large packaging benefit.

Average fuel weight of gasoline is 0.71kg to 0.77kg a litre. Let's take the most conservative number of 0.77kg/L to make the packaging savings the smallest.

20kg/0.77kg/L = ~26 litres or 2600 cubic centimetres of space. Measure it out and you'll realise how much of a packaging advantage designing a car with a 90kg tank will have over a car with a 110kg tank.

Is it really a problem with limousine wheelbase? Everything in motorsport is a compromise. I would rather put in all the fuel, and design the car that way. It gives you a better race car than if you only just fuel. It gives you more options, particularly late race safety cars while others are saving fuel, you're on fresh tires with plenty of fuel to burn.

I would rather have options at the expense of a little performance, I as a driver would instantly say I can make the difference. I'll take a car that qualifies 3rd but has race winning pace, vs a car that can qualify at the front but can't react to changes.

That's just a personal preference, I cannot speak for anyone else.

eg F1 designers - who would rather win races.

[godlameroso]

There is just 10 short months for teams to finalize their 2022 power units, no doubt everyone must still be working absolutely flat out to squeeze every bit of water out of that stone. Honda seems to be well placed to exit F1 with something they can be proud of having produced. If it's good enough for a team as determined to win as RBR then they can leave with no regrets, they fought with the best that Europe had to offer.

Renault and Ferrari are just now after 7 years of using the same layout just switching to the common layout. Just the fact of having all the OEMs with the same layout will create a lot of cost reduction potential.

F1 is a very big ship, and they do not change course quickly or easily, and like the Suez canal fiasco showed, if they're improperly driven they can cause big problems.

The change that's happening next year is a very big change, and it is particularly frustrating when the competition is as close as it is. The rule switch will only widen the gap again, because it takes months for teams to study the aero of the cars and manufacture parts strong enough to withstand F1 races. Whoever has a lead can keep that lead because it gives them more development options while others catch up. I have other views which I will keep to myself.

[nzjrs]

For some reason I have in my mind that the fuel tank bladder? Size? The whole thing? Is a standard part. Is that correct?

[trinidefender]

For some reason I have in my mind that the fuel tank bladder? Size? The whole thing? Is a standard part. Is that correct?

It's not. They do have to be built out of approved materials and I believe by approved suppliers.

[PlatinumZealot]

For some reason I have in my mind that the fuel tank bladder? Size? The whole thing? Is a standard part. Is that correct?

Not with the diffdrent chassis shapes.