[HN Gopher] Honda's F1 engine technologies that enable >50% ther...
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       Honda's F1 engine technologies that enable >50% thermal efficiency
        
       Author : ylk1
       Score  : 51 points
       Date   : 2025-03-20 04:42 UTC (18 hours ago)
        
 (HTM) web link (global.honda)
 (TXT) w3m dump (global.honda)
        
       | ylk1 wrote:
       | The only manufacturer to release any details about their
       | powertrain technology.
        
         | ylk1 wrote:
         | They've detailed their work on engine/MGU-K/MGU-H/ESS here:
         | https://global.honda/en/tech/motorsports/Formula-1/
        
         | metalman wrote:
         | UMmmmm, actualy there are no details, it's more like bait,
         | layed out in front of the rabbit hole. What it does
         | outline/hint at is the methodology of there thinking about
         | engine development, within the arbitrary rules of F1. And what
         | they, and everybody else leaves out, is that limitations in
         | material sciences is the reason for the engineering heroics,
         | and that access to say, the single crystal materials used for
         | jet turbine hot section blades, would allow higher combustion
         | temps and pressures, and greater efficiency, in NA engine, that
         | would outperform anything built yet. The reason that F1 cant do
         | that is money, and compared to true airospace development,F1
         | has lint in there pockets, and have falken back onto 1940's
         | turbocompound aircraft engine technology.
        
           | ylk1 wrote:
           | what are you even talking about? A lot of stuff is clearly
           | laid out on how they achieved better efficiency.
           | 
           | You can get more power out of NA with better materials you've
           | stated but not efficiency.
           | 
           | F1 wanted more road relevancy and hence ended up with turbo-
           | charging and Fuel limits
        
             | metalman wrote:
             | zero mechanical details, nothing verifiable is zero
             | information, plus there is a long venerable tradition of
             | lying like hell whenever you talk about competitive
             | advantages :) efficiency goes with materials, as a higher
             | temperature and shock loading, will permit higher
             | compression ratios, and that is as far as I know the only
             | way to exract energy from a piston engine well unless the
             | piston part is just viewed as a gas generator, but whoa
             | betsy, the rabbit hole is looming before us, and having
             | listened to folks involved in engine development (including
             | F1), I am just a spectator,engines are hard, and these days
             | anyone who could do ICE, is looking at other stuff, or
             | retirement ceramics have come close, but dont have the
             | reiability when produced at the scale needed for mass
             | market
        
       | pcdoodle wrote:
       | This sounds like a game changer, can it be adapted to low power
       | engines at some point?
        
         | ylk1 wrote:
         | Ferrari's partner MAHLE has pre-chamber ignition productized
         | for OEMs: https://www.mahle-powertrain.com/en/experience/mahle-
         | jet-ign...
         | 
         | I think, Maserati MC20 has this tech.
        
       | ikekkdcjkfke wrote:
       | What are the NOx emissions?
        
         | xhkkffbf wrote:
         | Given that they weren't optimizing around them, I'm guessing
         | not-so-good. But maybe I'm wrong.
        
         | mystified5016 wrote:
         | Nitrogen oxides, NO2, NO3.
         | 
         | They're generally toxic in large concentrations and I think a
         | greenhouse pollutant.
        
       | zelon88 wrote:
       | This is misleading. The article doesn't claim a specific thermal
       | efficiency anywhere. Not sure why the title of this post says
       | >50%.
       | 
       | Also, the engine itself is not achieving >50% thermal efficiency.
       | The propulsion system is a hybrid electric / ICE unit that is
       | designed inside and out to be able to recover potential energy in
       | a variety of ways, and then turn that back into kinetic energy
       | that propels the car.
       | 
       | So to say that the "engine" technology enables ">50% thermal
       | efficiency" is completely untrue.
       | 
       | Now, to look at the merits of the article. The specific
       | technology that they are claiming to have advanced here is "Rapid
       | Combusion" and "Lean Boost." Rapid combustion refers to the
       | layout of the fuel injectors in relation to the spark plug and
       | the fuel injector timing. In early SPFI (Squential port fuel
       | injection) vehicles and earlier, air was pre-prepared and fully
       | mixed with an adequate amount fuel before it entered the
       | combustion chamber. This mixture enters the combustion chamber
       | and is ignited by the spark plug. The flame front propagates away
       | from the spark plug until the (air within the ) mixture is
       | consumed.
       | 
       | What Honda is doing now is injecting only a small amount of fuel
       | into the combustion chamber up front. This small amount of fuel
       | is ignited by the spark plug, and then the rest of the fuel is
       | injected into the cylinder. This enables Honda to use another
       | technique called "lean boost" that has been around in diesel
       | engine technology for decades.
       | 
       | By initiating combustion with a small amount of fuel, the flame
       | front propagates faster and burns hotter. The added intensity of
       | the burn means that subsequent fuel injected into the cylinder
       | will self-ignite without any further spark from the spark plug.
       | These two flame fronts essentially "meet in the middle" of the
       | combustion chamber. Tech geeks can think of the performance
       | improvement of having two concurrent flame fronts propagating
       | simultaneously as an improvement similar to the data transfering
       | out of a RAID 0 array vs a single drive.
       | 
       | Because the fuel mixture is injected directly into the combustion
       | chamber, (instead of being mixed outside and then pushed in like
       | SPFI) pre-detonation is virtually impossible. Pre-detonation is
       | avoided in passenger cars by injecting more fuel into the
       | combustion chamber than what is required. This additional fuel
       | doesn't carry additional power, but it makes the mixture robust
       | enough to withstand high temperature and pressure long enough for
       | the spark plug to ignite the mixture in a controlled way. In an
       | F1 car, wasting fuel for this purpose is not acceptable. This is
       | where "lean boost" comes into play.
       | 
       | In a passenger car, the fuel mixture is already in the combustion
       | chamber when the piston begins it's compression stroke. So the
       | mixture must be robust enough to withstand being compressed by
       | the piston. In an F1 car, the fuel is absent until the piston has
       | reached the very top of it's compression stroke. So in an F1 car,
       | the fuel mixture isn't exposed to high temperature or pressure
       | until the very moment it is expected to burn. As a result it is
       | possible to inject a lesser amount of fuel than what is ideal.
       | The ideal mixture of air:fuel for petrol is 14.7:1. In a
       | passenger car this is a little bit lighter, say 13.5:1 to avoid
       | pre-detonation. In an F1 car they go the other way say 15.5:1,
       | because it saves fuel and there is no risk of pre-detonation due
       | to other design factors.
        
         | ylk1 wrote:
         | Mercedes crossed 50% thermal efficiency in 2018 with their F1
         | engine:
         | https://www.roadandtrack.com/motorsports/a15049580/mercedes-...
         | Their recent interviews suggest they are up by 2 to 3% on that
         | 
         | Honda did too but they never marketed the explicit number.
        
         | ylk1 wrote:
         | The geometric compression limit for F1 is 18:1. They make it
         | sound like they can go farther.
        
       | cromulent wrote:
       | The power unit in F1 generally refers to the ICE and the MGU-H &
       | MGU-K. This article doesn't mention nor specify the actual
       | numbers.
       | 
       | Mahle / Ferrari were getting 45% or so out of the ICE a few years
       | ago with pre-chamber ignition.
        
       | ylk1 wrote:
       | Most of the production engines still use tumble flow combustion
       | 
       | For reference: Nissan e-power with recuperation ~50%:
       | https://www.nissan-global.com/EN/INNOVATION/TECHNOLOGY/ARCHI...
       | 
       | Mahle ~45% with pre-chamber:
       | https://www.mobilityengineeringtech.com/component/content/ar...
       | 
       | Toyota dynamic force engines ~40% :
       | https://www.thedrive.com/tech/18919/toyota-develops-worlds-m...
       | 
       | Toyota's newest engines claim even more:
       | https://global.toyota/en/newsroom/corporate/40850156.html
       | 
       | Honda hybrid ~40%: https://hondanews.com/en-US/honda-
       | automobiles/releases/relea...
       | 
       | Startup Carnot engines claim 70% efficiency:
       | https://carnotengines.com/technology/
        
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