2014 Engines – some considerations

Posted: February 15, 2012 in Formula 1, Technology
Tags: , , , ,

As most F1 fans know by now, the engine regulations have been altered for 2014 onwards. The main changes can be summarized as follows: Cubic capacity drops from 2.4 lt to 1.6 lt and, at the same time, the number of cylinder goes down from 8 to 6, always in “V” configuration, revs are limited to 15,000 RPM, direct fuel injection is limited to 500 bar, single turbo charger is allowed and, finally, the fuel flow will be controlled (i.e. limited). For those interested in reading more, you can find the changes here. We will have the pleasure of watching turbo engines again after 26 years, for it was back in 1988 when the McLarens of Ayrton Senna and Alain Prost dominated the season, using a 1.5 lt V6 Honda turbocharged engine.

Many people believe that F1 engines are no longer the great differentiator in performance that they used to be, and that’s true. However, the level of competition is such at the moment, that one can never rest and there is always scope for development and investment. Recently imposed regulations such as the DRS have brought engine performance back under the spotlight. Renault, according to their F1 director Mr. Francois Caubet, have developed an engine so efficient that it allows Red Bull to start a race with 15 – 18 liters of fuel less than their opposition, even though it is slightly down on power in comparison to Mercedes (by about 15 BHP). Teams like Mercedes and Ferrari will be spending millions of dollars developing their engine plants, so I believe it’s worth examining the new engine regulations a little bit further.

Let’s start with the most intriguing aspect, which is of course the fuel flow rate limitation. The upper limit is set at 100 kg/h, and below 10,500 RPM the fuel mass flow must not exceed the amount of Q (kg/h) = (0.009 x RPM) + 5. This means, that the fuel flow tops up @ 10,500 RPM and has the linear graph shown below. Of course, the curve below represents the maximum allowed fuel flow in all circumstances and does not represent the actual flow graph, which will be considerably different.

Fuel Flow (kg/hr) Vs Engine RPM

The question is, how do we get more power in the 10,500 – 15,000 RPM range when our fuel flow is limited? Many people traditionally associate increase in power with increase in fuel supply, which is of course wrong. You can have an increase in power by using different (leaner) air/fuel ratios (and/or different ignition advance settings), and all modern engines are managed that way through air/fuel ratio maps which are embedded in the cars’ computer (and, quite often, tweaked afterwards…). Typically, a road car achieves 100% (or even slightly more) of fuel injector duty cycle at about 80% of its RPM range, and then has 20% more RPM to give (and, often, more power) by changing the air/fuel ratio and increasing the advance (i.e. increasing the degrees before TDC that the ignition takes place). So, you may end up getting 1,000 more RPM and at the same time the fuel injectors workload has dropped to 80% (these are ballpark figures).

The logical question is, how do we get more power by increasing the air/fuel ratio? The reason is stoichiometry. A stoichiometric mixture is considered an air/fuel mixture that has just enough air to burn the entire fuel quantity. For typical gasoline that we put in our cars, this ranges anywhere between 12.5 to 13.3. In F1 fuels, this may be slightly lower (due to the additives that have the effect of lowering the stoichiometric ratio). In reality, however, cars never run stoichiometric mixtures. There are three main reasons for that: (a) a stoichiometric mixture burns very hot and can impart severe thermal stresses to the engine components, (b) the temperature is further increased because we no longer have the cooling effect of the fuel spray on the combustion chamber and, (c) due to the high temperatures, early detonation of the mixture is possible, causing the famous “knocking” effect under load. All cars therefore (even F1 single seaters) use rich mixtures (i.e. air mass / fuel mass less than the stoichiometric one).

The new fuel flow rate limitation nevertheless means that F1 engineers will be forced to explore the upper limits of the air/fuel ratio. The increased ratios combined with increased advance will cause severe thermal stresses to the engines and will dramatically increase the cooling needs of the power plant. Also, since the cars will be turbo-charged, the charge air (i.e. the compressed air supplied by the turbo compressor wheel to the combustion chamber) must also be cooled down. Overall, thermal management of the engines will be crucial in 2014, and I expect most early reliability problems to come from that, as the aerodynamicists will be pushing for leaner sidepods and smaller coolers and air intakes. The engines themselves may be smaller, but this is more than countered by the addition of the turbo and the complexity of the exhaust piping arrangement (see further down in this post).

The problem of cooling is further exacerbated by one addition to the 2014 rules (5.8.2) which states that “over 80% of the maximum permitted fuel flow rate (author note: i.e. over approximately 8400 RPM), at least 75% of the fuel flow must be injected directly into the cylinders”. This means you have a very small time window to get all the fuel delivered directly via the fuel injectors (which are also limited to 500 bar), since you can only direct 25% of the fuel via the air intakes, which would help to keep the valves clean and to achieve more homogeneous mixtures inside the combustion chamber.

Also, the exhaust gases (having worked the turbine wheel) will have lost a lot of their kinetic and thermal energy, so there will be less scope for using them for aerodynamic purposes. Since only one, single-stage turbo is allowed, we will now get a single exhaust outlet from the turbo, although I don’t see anything in the rules preventing the teams from splitting the exhaust manifold in two after the turbo.

How does the 100 kg/hr compare to today’s F1 cars and consumption figures? Typically, contemporary F1 cars consume 75 lt / 100 km (4 mpg). 75 liters are about 68 kg. A typical race distance is around 310km and is done (again, typically) in about 1 hour and 30 minutes. This means that, currently, F1 cars consume on average 140.5 kg/hr of fuel. Please remember that the 100 kg/hr is the maximum amount allowed, we therefore expect the average number to be even less. Assuming (and that’s a big assumption) that the average figure will be around 80 kg/hr, this means that the new generation engines will be about 43% more economical than the current power plants. A 2011 car had to start the race with about 180 kg of fuel – in 2014 they will be starting with 120 kg. This means considerably smaller fuel tanks; and there’s a reason right there for the aerodynamicists to feel a bit better after all.

An interesting addition to the rules is 5.19, which states: “Engine exhaust gases may only exit the cylinder head through outlets outboard of the cylinder bore center line and not from within the “V” centre”. The way I understand this is that exhaust piping must travel outboard the engine and cannot be located in the middle, between the two cylinder banks, as shown in the figure below (the green area is where it’s not allowed to installed the exhaust outlets). This would have been an obvious solution for the engineers, i.e. to join the exhaust outlets from the two cylinder banks in one common manifold running between the V. Now, they will have to keep the exhaust outlets from the cylinder heads pretty much as they are at the moment and resort to more elaborate and complicated exhaust piping arrangements in order to feed the turbo charger.

Not allowed location for exhaust outlets

So, what should we expect from the 2014 engines? I am really not willing to get into the debate of how they will “sound”. They will sound terrific, just like they always have. For those who are interested in the technology, it will be fascinating to observe the new engines and the various solutions that the engineers will come up with.

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Comments
  1. I’ve had numerous arguments with different people about the 2014 engines.
    And having learned the lesson, I will not touch the theme “Why is that move exercised?” – fact is, it will happen. Yes, teams will have to invest millions of bucks to create competitive powerplants – for example, the cooling that you mention will be a huge challenge – the need of larger sidepods and cooling inlets vs. smaller tanks and possibilities for neat design.

    On the noise side – not worried at all. The frequency of the noise will be higher, plus GP2 cars run similar setup and they don’t sound bad. Certainly, the screams of the V12 and V10 units were different, but those times are gone.

    • abu says:

      I, for one, I am happy to see something new in F1 engines – it’s been a long time since we had anything interesting to write or discuss about. I remember the last truly interesting bit was the Renault engine of 2001 (or was it 2000?), with the extreme 120 degrees V angle. I don’t care if teams spend money or not, to be honest. I want to be intreagued and amazed by the various engineering ideas and innovations… :) :) :)

      • Dylan T says:

        I have a stock 1 litre in line 4. The noise from about 5k through to 13 is just awesome and even on stock legal cans can be heard from miles away. I’m not worried about the noise at all.

        The technical sideof the new engines is intriguing but so is the business side.Cosworth is out. PURE are developing an engine presumably to sell it ready to race for a car maker to slap a logo on it. Vw and Honda are rumoured to be interested in coming back. Could be a big shake up in the sport.

      • abu says:

        Really?! I knew about VW but was unaware of the Honda rumours… Coming from your mouth, it does carry a lot more credibility though.

        Besides, if you recall, you had accomplished the impossible. You had transformed me into a Honda fan. I will be chuffed to bits if they come back to the sport. I believe that Honda are great on the engineering side, but a bit unlucky with their timing. Very few people know it, but Honda were the only team to produce both chassis and engine when they entered the sport, apart from Ferrari and BRM(??). That may not mean much by itself, but few people know that Honda had produced their first road car barely 4 years ago…. But so unlucky with their timing… First Jo Schlesser’s death, then Harvey Postlethwaite’s death in 1999, then all the struggles with BAR and then Honda, only to abandon the effort when the fountain was in sight (2009). I hope they come back – I just wish they don’t supply McLaren. I will not be able to STAND all the Hamilton / Senna McLaren / Honda analogies… :)

  2. Jimbo says:

    2011 cars never started with 180kg of fuel… try 150-160 max

    • abu says:

      You maybe right of course – maybe the difference in fuel efficiency is less than 43% after all, it could be around the 30% mark. Will do some digging and see if I can come up with more accurate figures :)

    • abu says:

      Actually, here you can read (this refers to the days of refuelling, around 2004-2005, but the consumptions figures are not that different today) http://www.f1technical.net/articles/19 that fuel consumption in a 300km race can reach 200 liters. So, a 180kg of fuel is definitely what we should expect, more or less, in fuel consumption over 310 km (race distance that I used).

  3. Talisman says:

    Re: VW and Honda, VW have stated that they are interested in joining. Honda haven’t expressed interest publicly but they were sniffing around before the Tsunami. I’m not sure where they are now because after the Tsunami and Thai floods they’ve been hit quite hard, however at the Detroit motor show they revealed that they WILL produce the NSX which they had cancelled a few years ago so who knows?

    Honda only accidentally got into building their own F1 chassis back in the ’60s btw, they were in talks to supply Lotus or Cooper (can’t remember which) with engines but got dumped very late in the day. The team they were talking to were using Honda to negotiate with another engine company to get a better deal. In the end Honda couldn’t find a chassis partner so built their own chassis rather than scrap the whole project.

    I think Joe Saward is spot on with his analysis of McLaren, they want Daimler Benz to dump Mercedes F1 and get back into bed with them, after all Mercedes are a known and consistent partner. To this end they’ll help Force India humiliate Mercedes. I think they’ll only go for Honda or whoever else if this all falls through.

    Still, McLaren Honda, Williams Renault, Lotus Renault and Ferrari, stirs the memories doesn’t it?

    • abu says:

      I agree that McLaren want Daimler Benz to dump Mercedes AMG, but I think using FI to humiliate Mercedes is a long stretch. First they have to make sure that they keep themselves ahead of Mercedes, and then start to worry about how to use FI to humiliate them – I think there’s no better way to humiliate them, than for them to keep being faster than Mercedes. I think that Joe Saward’s assessment is a little bit clouded by both his, let’s say, dislike of the all-German Mercedes as well as his desire to discredit FI’s efforts due to his, erm, dislike of VJM. Frankly, I believe it’s a bit of wishful thinking from our Joe, and he’s stayed long enough in the game to know that it doesn’t work that way. McLaren are a serious team, and of course they want Daimler Benz exclusivity, but they also know that they only way to achieve that is to keep ahead of Mercedes AMG. If, in the meantime, their partnership with FI makes FI faster than Mercedes AMG, than that’s even better, but I am sure that’s not what they base their hopes on.

  4. Roger says:

    Hi, do you have any idea why the rules or so proscriptive/restrictive, e.g. the rule prohibiting exhausts from exiting within the cylinder bank, or requiring at least 75% of the fuel flow must be injected directly into the cylinders, or only allowing a single, single-stage turbo?

    Are all those rules aimed at reducing design options and therefore development costs, or…?

    • abu says:

      The formulation of the rules is an internal struggle amongst teams, and the end result is basically a settlement between conflicting interests. FIA would argue that the rules are to prevent excessive development costs and, also, to prevent one team from finding a huge competitive advantage somewhere and coming up with something that’s so good it destroys the opposition. That’s a romantic’s view and I don’t subscribe to it. I believe the FIA is indeed pushing for all these restrictions to minimize the scope of R&D (and make it more relevant to today’s eco times, e.g. the fuel flow limitation rule), but the devil is in the details. And the details are a result of teams haggling and arguing behind closed doors until they get what they want.

      • Roger says:

        Cheers. Just seems strange that something as specific as banning exhausts from inside the V would be specified!

      • abu says:

        Well, for this specific rule, I presume it’s to minimize the scope of different aero solutions. The positioning of the exhausts inside the V affect the aero AND the CoG, quite considerably. By preventing the teams to use this space, they are basically minimizing the chance someone to go down a different route and gain a significant aero or weight distribution advantage. These are just my first thoughts, but there may be more to that. :)

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