Its progress this yr, that has put it in an excellent shut title struggle with Mercedes, has been helped considerably by the work of engine accomplice Honda, which itself is main the F1 title standings for the primary time since 1991.
What’s most spectacular about Honda’s kind this yr is how rapidly its fortunes in F1 have circled. From the extremely powerful days with McLaren, its engine is now on a par with Mercedes – a formidable feat.
Honda has been fairly open concerning the type of modifications it launched with its present energy unit, and right here we check out a number of the particulars, and why they’ve been particularly vital.
On the coronary heart of the brand new energy unit lies a redesigned ICE, with quite a few modifications made that not solely assist to enhance combustion effectivity but additionally cut back the general dimension of the unit.
Paramount to this can be a new cylinder coating that was developed by Honda’s bike division and has rightfully been dubbed ‘Kumamoto plating’, owing to the manufacturing facility the place it was developed.
Whereas cylinder sleeve plating is way from a brand new concept, that does not imply you may’t nonetheless make advances within the subject, particularly once you’re making use of concepts and expertise from the commonly greater revving subject of bikes to a different challenge.
This new cylinder coating helps to scale back temperatures and friction, and this allowed the F1 division to rethink the design parameters of the engine block, as they had been now capable of run the engine tougher, for longer.
Honda RA620H vs RA621H cylinder spacing
Photograph by: Matthew Somerfield
This had a dramatic knock-on impact, with the design crew capable of cut back the general dimension of the ICE. This not solely led to a decrease place for the crankshaft to enhance CoG, it additionally coincided with a extra compact format that resulted within the design crew adjusting the bore pitch.
This primarily allowed Honda to maneuver the cylinders nearer to 1 one other, with out the worry that cylinder integrity is likely to be compromised. This has resulted in a shorter and narrower cylinder head.
As seen within the illustration (above), shifting the cylinders nearer collectively implies that the general dimension of the cylinder head might be lowered too.
The design crew additionally took this as a possibility to handle the ICE’s financial institution offset, because the RA620H which sported a ahead left financial institution (above, left), has been exchanged for a right-handed association for the RA621H (above, proper).
This has allowed for a number of the different energy unit components and ancillaries to be repackaged whereas additionally altering the general steadiness too.
Engine cylinders head covers
Photograph by: Honda
As a consequence of those dimensional modifications to the cylinder head, the cylinder head cowl has additionally gone by a dramatic overhaul too. That is evident when the RA620H’s cylinder head cowl is in contrast with a prototype for the RA621H in a picture launched by Honda earlier this yr.
The one similarity between the 2 covers is the mounting body for the ability unit, the positions of that are ruled by the rules.
Having a look on the cylinder head cowl from one finish (under), not solely is the form totally different between the 2 specs, owing to how they mount to the pinnacle, however the spacing between the cams has been lowered massively too, altering the valve offset because of this.
Honda Powerunit CAM distance comparability
Photograph by: Matthew Somerfield
Altering the angle of the valves alters the angle of the move into the cylinder too, which has possible been met by additional modifications to the design of the valves and inlet and outlet ports.
However, maybe extra importantly, all of those alterations have led to a better compression ratio. This has possible resulted in a change to the design of the piston crown too.
Honda valve association
Photograph by: Matthew Somerfield
The modifications to extend the compression ratio and combustion effectivity do have a draw back although, as the quantity of exhaust power being created is lowered, leading to much less electrical power being recovered by the MGU-H, which clearly leaves a shortfall when it comes to deployment.
To counter this, Honda has additionally redesigned facets of its turbocharger, with one other division inside the firm at hand to lend help, as soon as extra.
Having helped the F1 division when it switched to the bigger, outboard mounted compressor and turbine in 2017, HondaJet was completely positioned to assist revise the form of the turbocharger’s impellers and offset the decrease move quantity.
Why did Honda really feel compelled to overtake its energy unit design, particularly because it had already approached an analogous stage of efficiency to Mercedes in 2020?
The reply lies in how Honda’s earlier energy models had put extra of an onus on the restoration and deployment power, forsaking some combustion effectivity as a consequence.
Technical directives issued by the FIA earlier than and in the course of the 2020 season scuppered these methods and eroded any efficiency features that may have been attainable with a future growth programme centered upon them.
As such Honda, which had already deliberate to introduce a brand new energy unit for 2021 earlier than electing to delay the plan, determined to reverse its actions and produce the brand new design ahead as soon as extra.
This can give it a good higher understanding of the brand new energy unit design forward of the introduction of E10 fuels in 2022, which it’s persevering with to work on with Crimson Bull regardless of its imminent withdrawal from F1.
One of many huge upshots of shrinking the ability unit and decreasing its centre of gravity is the efficiency that has been gained on the chassis facet, one thing that is of even higher significance given the homologation freeze in place this season.
This has undoubtedly helped each AlphaTauri and Crimson Bull make headway when put next with final season, and has resulted in a a lot tighter rear finish on each vehicles.
The aero departments have due to this fact been capable of benefit from the tighter energy unit packaging and what seems to be a decrease cooling requirement.
Max Verstappen, Crimson Bull Racing RB16B
Photograph by: Charles Coates / Motorsport Images
Clearly comparisons might be drawn with Honda’s return to the game in 2015 right here, with McLaren’s claims of a ‘size-zero’ rear finish now lastly realised.
And, whereas many suspected that the Japanese producer may wind down its growth push having closed the hole to Mercedes final yr, the precise reverse has been true. It has labored diligently to speed up previous Ferrari and Renault en path to its final aim.
Honda’s push forwards hasn’t been with out hardship although and the ability unit has gone by quite a few transformations alongside the best way.
The RA615H featured a break up turbocharger association akin to the one pioneered by Mercedes only a yr earlier however, in an effort to preserve the ability unit’s silhouette as small as attainable, the compressor and turbine had been additionally housed inside the confines of the engine’s V.
In the meantime, a low-line inlet plenum and log-style manifold are simply two of the opposite standout options that had been designed to maintain the ability unit as small as attainable in an effort to assist McLaren in its quest for a smaller, extra aerodynamically environment friendly rear finish to their automotive.
The RA616H was a growth of its forebear, because the Japanese producer was restricted in what it may change concerning the structure whereas additionally attempting to contemplate the goals of accomplice McLaren.
Nevertheless, in an effort to make features, a swap to a standard multi-branch exhaust manifold was made. The inlet plenum was additionally enlarged and the general design of most facets of the ability unit elevated in dimension barely so that it had extra margin inbuilt to ship sturdiness – a serious situation in the course of the first season.
Honda Energy unit 2015-2018
Photograph by: Matthew Somerfield
2017 noticed Honda make its first main change in format because it tried to resolve a number of the main drawbacks of its preliminary design.
Honda retained the break up turbo strategy however fairly than be housed completely inside the V, it moved to a design extra carefully aligned with Mercedes’, whereby the turbine and compressor are mounted on both finish of the engine.
This ‘pancake’ model association, as it’s identified, gave Honda extra headroom when it comes to the turbo design but additionally created some extra engineering complications because the connecting shaft and MGU-H needed to be redesigned to account for the higher distance between the turbine and compressor.
The combustion chamber design was additionally altered on this redesign and, as soon as once more, you may see the inlet plenum and exhaust system had been adjusted in correlation. Even with these substantial modifications the 2017 energy unit was really down on whole output when in comparison with its predecessor, which grew to become the straw that broke the camel’s again in its relationship with McLaren.
Nonetheless, even given the discount in output, this transition was obligatory, because the earlier design had reached a useless finish. However Honda’s swap to Toro Rosso proved to be a turning level in its F1 fortunes.
Toro Rosso STR13
Photograph by: Giorgio Piola
The RA618H continued to construct on the foundations of the ability unit redesign of the earlier season, with loads of modifications beneath the hood and the standard redesign of the inlet plenum and exhaust.
In the meantime, Honda and Toro Rosso labored on the set up facet too, as the previous made concessions when it comes to altering the placement of the enhance pipework, whereas Toro Rosso put in a ‘saddle’ cooler above the ability unit in a similar way to how McLaren had executed so within the years prior.
The RA619H was to be the primary Honda energy unit to be put in inside multiple crew and, whereas the connection with Toro Rosso had been a great one, having Crimson Bull onboard would convey with it a higher weight of expectation.
The RA619H and the RA620H that adopted noticed Honda capable of seize double the info and use that to make regular progress when it comes to output and sturdiness earlier than making the most important modifications we have already outlined for 2021.