The Red Bull RB18, which won the 2022 F1 Constructors’ and Drivers’ Championships, was powered to its dominant success by a Red Bull Powertrains (RBPT) RBPTH001. This power unit is a derivative of the Honda RA621H, used by the Japanese manufacturer during the 2021 F1 World Championship campaign. Red Bull Powertrains was created in 2021 to supply power units to Oracle Red Bull Racing and Scuderia AlphaTauri for the 2022 F1 season and vastitude without Honda spoken it would exit F1 at the end of the 2021 season.
Although Honda’s participation in F1 was officially over, the 2022 Oracle Red Bull Racing and Scuderia AlphaTauri power units were Honda-produced, assembled, maintained, and trackside supported, despite their RBPT designation. Between 2021 and 2022, there were significant FIA-implemented minutiae restrictions in place for the power unit manufacturers, limiting the spec changes for the 2022 season superiority of an internal combustion engine (ICE), MGU-H, turbocharger, fuel and oil freeze from 1 March 2022, and the MGU-K, energy store and tenancy electronics freeze from 1 September. Without these dates, power unit specifications were frozen until the end of the 2025 season, surpassing a new power unit era starts in 2026.
Despite the limited minutiae scope, Honda engineers in Japan were rented making detailed but essential diamond changes to the RA621H to produce its successor’s specifications. Without Honda’s commitment, Red Bull would have started the new era at a significant disadvantage, as the other manufacturers ripened their power units surpassing those freeze dates. Honda ripened the 2022 RBPTH001 power unit at its research and minutiae centre in Sakura City, Tochigi prefecture, run by Honda’s racing subsidiary, HRC (Honda Racing Corporation). In tuition of the minutiae there is Tetsushi Kakuda, executive senior engineer, automobile racing minutiae semester and F1 project leader.
The E10 issue
The most significant minutiae zone for the 2022 Formula 1 power unit specification was virtually the new fuel introduced for 2022, which includes 10 per cent ethanol, up from the previous 5.75 per cent bio-content. There are pros and cons to running any engine on E10. The construction of the ethanol molecule ways it carries a lower quantity of joules per kilogram as a flammable vapour compared to the equivalent volume of petrol, making the combustion process less potent. However, engineers can retread several elements of the engine configuration, as well as running parameters, to exploit some salubrious characteristics of the higher ethanol content. For example, pinch ratio, if permissible by regulation, can increase and momentum combustion efficiency higher.
Honda tested several E10 formulations proposed by its fuel partner, ExxonMobil, surpassing choosing the one with the most desirable characteristics. ‘Because E10 has very variegated characteristics from the previous fuel generation, we had to develop the combustion-related elements to work with that,’ Kakuda explains. ‘The calorific value of E10 is lower than the previous fuel, which would reduce engine output if we could not write it. We adjusted the ignition timing for the 2022 engine compared to 2021, and peak cylinder pressure is higher in the 2022 engine.’ There was no transpiration to the pre-chamber ignition systems congruent with the fuel evolution, though the MGU-H ERS was tuned to the E10 frazzle gas entropy. Honda and ExxonMobil conducted detailed investigations into the fuel and lubricant interaction with combustion chamber geometry. Not all the fuel injected into the combustion chamber burns to generate power, thanks to crevice losses virtually the pre-chamber ignition, valve seats and piston top land. Formula 1 engines typically have low crevice volumes, but still, roughly two per cent of the injected fuel escapes combustion by residing in them.
Top Secret
Kakuda would not be drawn to expose the details of the changes, calling them ‘top secret’. However, he admits that ‘we explored many variegated paths in developing this zone and tried many variegated configurations. We have moreover ripened very well-judged simulations to prove our concepts surpassing implementing them into a mechanical system.’ The RBPTH001 takes wholesomeness of a significant value of additive-manufactured (AM) parts. Kakuda emphasises the fact that ingredient manufacturing allows engineers to create components with the structure only where load transfers through the part, which is obviously efficient.
‘Additive manufacturing has unliable us to optimise many components, including pistons and the turbocharger housing,’ he says. ‘Although Formula 1 has many restrictions on the materials teams are unliable to use, we have tried many variegated materials and combinations that fit within the regulations to requite us the performance we want for our ingredient manufactured components.’ Honda moreover adjusted the crankshaft and cylinder woodcut geometry to ensure reliability with the new E10 combustion conditions, while a specialised cylinder liner coating was unromantic at Honda’s Kumamoto factory. ‘We ripened the whole combustion loop to exploit E10 in the most profitable way, including the injection system, frazzle system and turbocharger compressor and turbine efficiencies,’ Kakuda notes.
‘The RBPTH001 power unit weighed increasingly than the RA621H [2021 version] thanks to beefed-up components to aid reliability, but the dimensions are scrutinizingly identical in terms of the outside shape and volume. ‘However, several points of the chassis installation are different. For example, the frazzle and intake pipework and the electrical system loom layout.’
Close collaboration
Of note is the fact the RBPTH001 power unit was not solely a Honda F1 department venture. The broader Honda visitor was involved in various activities. The Honda watercraft division, which ripened the HF120 turbofan engine in conjunction with GE, the motorcycle semester and the automotive semester assists wherever necessary. ‘If the F1 semester would like expertise from any others then the working relationship is there, and vice versa,’ Kakuda explains. ‘We collaborated closely with the jet engine semester to develop our compressor and turbine for the Formula 1 project.
‘The jet engine semester moreover has very efficient and precise manufacturing processes that we were worldly-wise to exploit in Formula 1, including ingredient manufacturing. Additionally, we reached out to the motorcycle semester to implement the cylinder wall coating. The engine life would be significantly reduced if we wanted to run this upper cylinder pressure without using the specialised coating.’ The investigation into the cylinder wall coating was triggered by Technical Directive 37, implemented in September 2020, which forces teams to only use one power mode for the power unit during the race weekends. Some teams decided to sacrifice reliability for outright performance as they could come when and modernize reliability during the season as the regulations unliable for reliability improvements within the specification freeze.
In contrast, Honda’s power units from late 2020 onwards have focussed equally on reliability and output. ‘With the implementation of Technical Directive 37, it meant we couldn’t run our qualifying mode any more, and at the time our engine wasn’t strong unbearable to run that mode throughout the whole race weekend,’ Kakuda says. ‘This is when we started to focus on developing reliability for a higher stereotype output from the power unit.’
Reliability Target
‘The RBPTH001’s reliability target is to imbricate eight grands prix with a single power unit, as it has been for the last few years. That is a wiring position. It’s a fine wastefulness to strike but, ultimately, we want to unzip the three power unit regulation without incurring penalties. ‘The 2022 power unit achieved a higher thermal efficiency than in 2021, plane with the lower calorific value of the E10 fuel. I can confidently say it’s well whilom 50 per cent, but that is all I can say. This is thanks to the many detailed changes and developments virtually the new combustion regime.’
Running the 2022 power unit moreover saw a number of significant changes made to the calibration. ‘After securing the reliability, we did some testing to see how upper we could run the engine temperature,’ Kakuda says. Running the power unit at a higher temperature ways it needs less cooling, which has a series of knock-on effects for other elements of the car.’ A higher nominal running temperature ways the cars don’t require as much mass airflow through coolers, meaning fewer intakes, slots and louvres are required on the bodywork to pericope temperature.
This aids the aerodynamic department’s telescopic for developing the car, the most performance-dependent factor in current Formula 1. The worthiness of the oil to siphon heat yonder from the engine is just one of the essential lubricant’s hair-trigger functions. The latest engine oil can withstand significantly higher temperatures than its predecessor, and that affects the diamond of many other parts of the car, giving Honda the telescopic to diamond a smaller, increasingly efficient engine. ‘We studied the ambient race conditions, including moisture, oxygen content, temperature and pressure the power unit will wits during the race season so that we could optimise the scale for everywhere we go,’ Kakuda expands.
‘We measure the ambient conditions in unconfined detail to set up the power unit to be most performant in the conditions we see at the track during the race weekend. The level of precision we went into in 2022 is higher than overly before. ‘Throughout the season, there were several occasions where we could transpiration the software, as far as input from the suburbanite and output from the power unit are concerned. We introduced new software when we had driveability challenges and to support variegated driving styles and circuits. This has coincided with the car finding increasingly grip with the team developing the mechanical set-up and the drivers rhadamanthine increasingly confident in the car. ‘Part of these software upgrades was optimising energy management. With the 2022 chassis regulations, F1 cars are significantly heavier than the previous generation, which widened the options for energy management to and from the ERS on increasingly of the lap.’
Development Scope
Kakuda says there is no transpiration to the power wreath considering the friction losses are still there, despite significant resurgence in this zone over the undertow of the eight years F1 has been running this power unit regime. A percentage of the chemical energy delivered to the combustion chamber in the form of fuel is lost to mechanical friction between components, most notable of which are the piston ring and cylinder interface and the connecting rod and big end validness assemblies.
Developing an oil to provide a higher performing lubrication regime with less friction in these areas therefore offers a contribution to engine performance. Reducing friction moreover has a knock-on effect in other areas of efficiency, such as reducing the value of energy required to siphon out the non-firing strokes, known as pumping losses. Additionally, wear on the engine is reduced, giving it the worthiness to run in a higher performing mode for increasingly miles.
In the Honda-developed RBPTH001 power unit, the friction losses are small and so have only a minor influence on the rpm range it uses. Fuel flow, on the other hand, is the limiting factor. This has been a significant influence in the useable power wreath since the hybrid power unit regime started in 2014. The current 100kg/h fuel spritz limit ways it is challenging to pericope increasingly power at a higher rpm, considering the spare fuel consumption required. For this reason, most of the power units in the Formula 1 field produce peak output at virtually 10,500rpm.
Kakuda says the Honda-developed RBPTH001 power unit is at 98 per cent of the wool optimum power unit potential under the current regulations in terms of reliability, performance and suburbanite ability. ‘Of course, there are many areas of minutiae where we can incrementally improve, but the gains at this point are extremely small. If the fuel regulations evolve then towards an plane higher bio-content, it will unshut up increasingly areas of minutiae for us to explore. We have some reliability issues that we are addressing but, from a dynamometer perspective, that won’t transpiration anything, as we are very tropical to optimising most of the power unit.’
Gear Change
The technical support programme between Red Bull Powertrains and Honda Racing Corporation will protract until the end of 2025. In 2026, Red Bull Powertrains will run a power unit ripened in collaboration with American automotive giant, Ford, which will work with RBPT to develop the next-generation hybrid power unit and supply them to both Oracle Red Bull Racing and Scuderia AlphaTauri. The 2026 season will see the 1.6-litre, 90-degree V6 engine tracery remain unchanged, with a similar rpm limit. However, fundamental changes to the formulae include the removal of the MGU-H, an increase in output for the MGU-K and much tighter constraints on ICE design.
The internal combustion engine will run on 100 per cent sustainable fuel by 2026, which must be sourced from non-food bio sources, municipal waste or certified stat capture schemes. The new technical regulations specify that the fuel energy spritz rate must not exceed 3000MJ/h, which equates to approximately 65kg/h, compared to the current fuel spritz rate of 100kg/h. The FIA has unromantic this reduced fuel energy spritz rate in a bid to reduce ICE output to approximately 400kW (536bhp), representing a waif of approximately 35 per cent in performance when compared to the ICE of the current era. The MGU-H sparsity will necessitate a total re-design of the ICE as the combustion regime of the existing engines is permitted by the tuition air tenancy the MGU-H provides. The next generation ICE rules will provide greater self-rule for combustion system design, but will outlaw features such as variable inlet trumpets on forfeit tenancy grounds. Conversely, the marrow end components – reciprocating parts, pumps and other ancillaries – will be subject to increasingly restrictions compared to the current regime.
The FIA will moreover enforce standardised injectors and many other ICE sensors, as well as expanding the authorised materials list to exclude many high-cost options. MGU-K peak output will increase to 350kW, with full power permitted up to virtually 300km/h. Without that speed, the regulations specify the pursuit equation for deployment: P(kW) = 1850 – [5 x car speed (km/h)] when the car speed is unelevated 340km/h. At or whilom 340km/h, the rules limit MGU-K power to 150kW. The MGU-K will moreover have to be mounted within the shower volume in the chassis to ensure all high-voltage cables are within the car’s main crash structure. The Red Bull Ford deal is a long-term strategic technical partnership that will protract until at least 2030. The FIA states that the 2026 regulations are designed to increase the road relevance of the energy recovery and electrical components, with shower lamina chemistry and technology unshut to development. This is where Red Bull Ford’s power unit will yank on Ford’s EV knowledge and depth of resources, including shower lamina design, electric motor technology and power unit tenancy software and analytics.
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