Honda F1 project leader Yusuke Hasegawa has outlined a number of reasons why Honda has been struggling so badly in the beginning of the 2017 Formula One season. He confirmed that lots of problems were not discovered while running on the dynamo meter.
It looks like they propagate a Shockwave across the cylinder roof, and another across the crown of the piston, and make them converge in the head-gasket crevice.
Maybe that's how the 2021 Honda heads shrunk? Maybe they used the BMW head-on-cylinder casting method, and it's a machined crevice of particular design?
The flame is a result of radicals interacting and releasing energy. There is no convergence of flame, there is strong recirculation at the cylinder walls. If you look closely you see a jet just peeking out of the spark-pre-chamber as the flame at the cylinder edge is forming. The most turbulent regions ignite first, remember the fuel has already been sprayed into the chamber at this stage.
This is a very controlled swirl and turbulence recirculation.
this is my first post after my ban
Thank you to posters for their very good video and picture of honda pu.
I want to share a video that a researher talks about Tji combustion.
this is my first post after my ban
Thank you to posters for their very good video and picture of honda pu.
I want to share a video that a researher talks about Tji combustion.
At 20 minutes you get a hint as to why it seems like the flame starts at the cylinder walls. The jet has produced unburned OH* radicals that have not yet ignited the mixture. It is only when the chemical reaction fully takes place that we see the flame. The actual jet has already filled the combustion chamber, and the parts you see igniting are the most turbulent regions in the CC where the most mixing and circulation has taken place.
My theories with my knowledge level;
Egr dilution and air dilution effects road engine but I think air dilution has lesser effects on combustion at F1 engine and there is not egr. Because F1 engines are not aiming fuel efficiency like a road car and F1 engines works at higher revs I think air dilution has lesser effect. I read somewhere or heard at this video that more heat effects combustion speed.
I think difference between conventional engine combustion with Honda engine at the video that @KAIZEN shared is combustion speed. It seems to me that normal engine's combustion propagates but f1 engine's looks more like diesel just after flame jets. It maybe because of heat or it maybe something like Mazda's explanation of their combustion system. It is "spark plug ignites rich mixture which is injected towards spark plug just before the desired ignition time and this increase heat and pressure inside cylinder then mixture in the chamber ignites spontaneously and simultaneously because of this heat and pressure.
Last edited by etusch on 19 Jan 2022, 11:19, edited 1 time in total.
.... Because F1 engines are not aiming fuel efficiency like a road car and F1 engines works at higher revs I think air dilution has lesser effect. I read somewhere or heard at this video that more heat effects combustion speed.
I think .....
in F1 compared to road cars at full power .....
F1 gas temp is higher near tdc (from higher mass-specific compression work ie high(er) supercharging and cylinder CR)
this helps combustion to start and proceed
F1 gas temperature is lower during/after combustion (the gas mass-specific energy is lower)
so less energy needs to be taken by coolant
so the total mass of gas has more (total) energy for conversion to work
so F1 gets more work from its limited fuel rate and fuel quantity
and ...
F1 'boost' pressure etc shows that AFR must be unusually high ie by design the engine systematically dilutes its heat
.... Because F1 engines are not aiming fuel efficiency like a road car and F1 engines works at higher revs I think air dilution has lesser effect. I read somewhere or heard at this video that more heat effects combustion speed.
I think .....
in F1 compared to road cars at full power .....
=>> F1 gas temp is higher near tdc (from higher mass-specific compression work ie high(er) supercharging and cylinder CR)
this helps combustion to start and proceed
F1 gas temperature is lower during/after combustion (the gas mass-specific energy is lower)
so less energy needs to be taken by coolant
so the total mass of gas has more (total) energy for conversion to work
so F1 gets more work from its limited fuel rate and fuel quantity
and ...
=>> F1 'boost' pressure etc shows that AFR must be unusually high ie by design the engine systematically dilutes its heat
I was trying compare inconsistancy of jets at the video I have shared with F1's tji system. It is impossible to avoid inconsistancy of jets, but I think F1 engines are naturally better at getting jets from prechamber because of what you had said. I just couldn't explain good enough
I have transcribed the subtitles of the Polish video.
INTRODUCTION
Despite many failures and humiliations that faced Honda after returning to competition, the goal that guided Japanese engineers from the very beginning has not changed.
To beat Mercedes.
To build the best power unit in the field.
And even the information about quitting the game did not change this approach.
On the contrary, they became even more hungry for victories, and even more courageous in introducing new solutions.
Each story has its heroes, each of them also has so-called turning points.
It is no different here, and the turning point that allowed Honda to catch up with Mercedes was the development and implementation of a new combustion technology called by Honda high-speed combustion (HSC).
To understand how high-speed combustion technology works, we must go back to 2017, when Honda also made a very big step forward by implementing Turbulent Jet Ignition technology also known as Jet Ignition – a technology that uses so-called pre-combustion chamber.
TURBULENT JET IGNITION 1:10
The aforementioned pre-chamber with small holes separates the spark plugs and the injector from the rest of the chamber.
It is there that a very rich mixture is ignited, and hot streams through the holes enter the main chamber, where there is a much poorer mixture.
It ignites many of its places at the same time. Instead of a single ignition point, we have several of them, which significantly speeds up the combustion process and increases the power of the engine.
The mentioned technology became famous in 2015 mainly due to comments from Bernie Ecclestone and Gerhard Berger.
It was this technology that was to be the reason for this early dominance of Mercedes at the start of the hybrid era.
In addition, in the winter between 2014 and 2015 this technology was to be put under the roof of the factory in Maranello through the MAHLE company.
The aforementioned technological transfer was to have its godfathers, all in order to make the competition more evenly matched.
Although the history of this technology transfer has never been confirmed in the Formula One world, one of the MAHLE engineers has made it creditable, mentioning that Turbulent Jet Ignition is present in the racing area, and one of their customers is Ferrari.
TJI technology allowed to achieve high efficiency of the power unit with a very lean mixture, which in the era of fuel limits perfectly fit into the new hybrid reality.
Despite a lot of progress, Honda was still years behind its rivals and what it needed was a big breakthrough.
HIGH SPEED COMBUSTION 3:06
It came, as it often happens in life, a little by accident.
One of the engineers working on improving the unit’s efficiency noticed anolmalies in the data – momentarily a very large jump in power.
When the looked at it even more closely, they found that, under certain parameters, it would self-ignite right next to the piston surface, ideally when these hot jets penetrate the combustion chamber, as they are ejected from the pre-chamber.
They found that the combustion reaction, initiated from above and below, is very rapid and means a large increase in power output.
At the same time, it is very difficult to control, therefore it requires hundreds of hours of work and the development of a completely new fuel.
This fuel, the recipe was created in Sakura, and the production was done by ExxonMobil.
This technology made its track debut during the 2018 Russian Grand Prix and allowed Honda to reach a completely new, previously unattainable level.
It is worth remembering that each action triggers a reaction.
The extra power also puts extra stress on the engine.
Further progress required better protection of the power unit or its strengthening.
It was in these areas that the focus was on in Sakura, creating the RA619H – a unit for the 2019 season.
The entire combustion unit was strengthened with particular emphasis on the combustion chamber and the piston crown.
Upgrades introduced during the 2019 Azerbaijan GP allowed the use of additional power for a much longer period.
Further modifications to the combustion process where checked during the French GP also in 2019 where the experience of the HondaJet division in the area of improving the air flow around the compressor blades was also used.
There is not much information about these upgrades other than the name of the project – Honda Gas Turbine Flow Project.
It wasn’t the first time jet engineers have supported Honda racing division.
Back in the McLaren era, the improvements suggested in the area of the shaft connecting the turbine to the compressor eliminated vibrations – the vibrations led to the car’s frequent breakdowns on the track – these are the days of the GP2 engine.
FORGOTTEN MOTORBIKE FACTORY 5:16
The great potential hidden in the technology of fast combustion is evidenced by the fact that in 2020 it was once again decided to follow the path of evolution, despite the fact that completely new concepts were implemented during the first 3 seasons.
The wear of the power unit was still a major limitation.
The solution was found at Kumamoto manufacturing – Honda’s motorcycle factory, which had for many years had a special engine plating technology.
A special protective coating developed for the needs of the new unit made the cylinders wear several times slower.
Increased reliability allowed for further changes, especially in the shape of the piston crown, to make high-speed combustion even more efficient.
SUPPORT FROM RED BULL 6:01
There would be no such rapid progress, without the proper support from Red Bull.
What drove the Honda engineers to the bottom – I am talking about the requirements of McLaren and the size-zero concept, i.e. the construction of a very small, very compact power unit, completely subordinated to aerodynamic requirements, this time has become a springboard.
The purchase of special test beds by Red Bull and the creation of a dedicated team in Milton Keynes gave Honda engineers an additional safety buffer.
A Guarantee that bad ideas will not end up on the track.
In addition, the high-speed combustion technology is so advanced that each individual combustion unit needs an individual calibration process.
It is this process that, in its entirety, before the units hit the track, is done in UK.
One idea that would probably never have left Sakura’s walls without this extra safety buffer is what is called CAC Bypass 2 or CB2 in Honda’s documentation.
Here again a word of introduction is needed.
In the hybrid age, squeezing as much energy out of a fuel unit as possible is a key task, but not the only one.
The second task is to keep this energy in the system as long as possible.
The mentioned CAC Bypass 2 – CAC is anabbreviation for Charge Air Cooler it is such a clever way to keep energy in the system.
According to Japanese sources, previously the excess boost pressure was simply thrown into the atmosphere via a special pop-off valave (POV) – energy was wasted.
Honda engineers decided to redirect the excess pressure through a special channel to the exhaust system.
In this way the high-pressure air additionally drives the turbine.
This way, energy is not wasted – it remains in the system all the time.
The amount of energy recovered at full throttle increased by as much as 10%.
Although the track ultimately confirmed the estimates of Honda engineers, the first attempt at the Milton Keynes base did not go well.
This first piece of testing PU broke before any valuable data was evr pulled out.
It was only [when] another one [was] sent from Sakura that the Red Bull engineers couldn’t believe the numbers they saw.
DANGEROUS HARVESTING 8:14
This is not the only legal trick implemented by Honda – it will be about the less legal ones later.
Another is the aggressive energy recovery mode Honda calls “Extra harvesting mode”.
It is a very creative way to bypass the limits on the systems and the amount of energy recovered.
The regulations clearly state that only 2MJ of energy [may be] recovered by the MGU-K system can be stored in the battery system.
What if the energy recovered from the braking system is 3MJ or more?
In the case of the Honda unit, the additional energy from the MGU-K system is sent to the MGU-H, and from there, after a few symbolic engine revolutions, it is sent back to the battery system.
The whole thing is a bit like a flywheel solution used for energy storage.
In this case, the flywheel is the MGU-H motor, and what drives it is MGU-K system.
Brilliant, you have to admit, in its simplicity.
However, not everything that was created under Sakura’s roof appealed to the FIA specialists.
This is indicated by a loss of about 10 horespower just before the delayed start of the 2020 season, shown in the official documents of the Japanese manufacturer.
The whole thing coincides with the entry into force of four technical directives that were the result of cooperation between the FIA and Ferrari.
This is the aftermath of this secret settlement made after the 2019 season.
The new guidelines have affected energy recovery systems, among other things, and closed a certain grey area of the MGU-H use developed in cooperation with HondaJet.
The details of this system are still missing, but the change in interpretation of the regulations was so important the the Japanese manufacturer had to introduce a new engine control system (CE) and was one of the reasons for introducing a completely new version of the power unit in 2021.
RA621H – NEW HOPE 10:01
New PU design, called RA621H, was a collection of all the experience of Honda engineers and an attempt to unleash the full potential of high-speed combustion technology.
This goal was achieved not only by reducing the angle between the intake and exhaust valves and introducing a new cylinder head geometry, but also by using a completely new production technology.
The elements that have so far been made by casting have been produced with the use of advanced cutting technology from a single block.
As a result, they have become not only more durable, but also lighter.
According to Honda data, this change alone increased the durability of the Honda unit by a staggering 70%
An interesting fact is that the entire process is performed using the same tools that are used by Honda for the production of road cars.
The Japanese manufacturer also actively uses the technology of creating metal elements using 3D printing, which significantly reduces the production time of some components of the power unit, such as the compressor housing.
NEW ENERGY STORE 11:04
The experience of the Honda Group has been deeply reached.
The low efficiency of the battery system compared to its rivals, which manifested itself mainly on fast tracks and long straights, prompted Japanese engineers to build their own solution.
The 8-year-long development work on cells based on the so-called carbon nanotubes (CNT) was used to create a revised version of the battery system.
Thanks to the use of this technology, the time of charging and discharging cycles of such a battery system has been significantly reduced.
A smaller, lighter, yet more efficient solution was first tested at Spa in 2021.
The goal, the dream of the Japanese engineers, was to beat Mercedes, especially in qualifying, and they did it.
Honda intends to implement similar solutions soon not only in the automotive industry, but also in the aviation industry.
They are currently pending a patent.
In this whole remarkable process, Honda has not forgotten the development of young engineers.
One of the tasks concerning Verstappen’s weak starts has been entrusted to just such two groups of young engineers.
One worked in Sakura, the other in Milton Keynes.
Many months of analysis, which began in 2019 season, indicated that the cause of the problems on the starting fields is the underdeveloped engine characteristics in the area where the anti-stall system is activated.
A system that prevents the engine from stalling on the starting field.
The solution suggested, developed by these young engineers, something like a virtual intake extension at low revs, was used for the first time on the Imola circuit in 2021 and Honda was very pleased with how it worked.
IT’S NOT OVER YET 12:47
While Honda has announced its departure, the story is certainly not [at] the end.
Soon, most of the Japanese manufacturer’s engineers will be under the wings of Red Bull Powertrains.
The pre-freeze development of the unit continues in Sakura, and ove time the burden of maintaining the engine operation will be transferred to the new Red Bull factory.
How many more interesting and unconventional solutions will Red Bull and Alpha Tauri drivers find behind their backs?
We will find out about it soon…
I have transcribed the subtitles of the Polish video.
INTRODUCTION
Despite many failures and humiliations that faced Honda after returning to competition, the goal that guided Japanese engineers from the very beginning has not changed.
To beat Mercedes.
To build the best power unit in the field.
[ ......... ]
IT’S NOT OVER YET 12:47
While Honda has announced its departure, the story is certainly not [at] the end.
Soon, most of the Japanese manufacturer’s engineers will be under the wings of Red Bull Powertrains.
The pre-freeze development of the unit continues in Sakura, and ove time the burden of maintaining the engine operation will be transferred to the new Red Bull factory.
How many more interesting and unconventional solutions will Red Bull and Alpha Tauri drivers find behind their backs?
We will find out about it soon…
That was certainly a lot of work. Very kind of you and much appreciated. So ....
