P.U.R.E: 2014 F1 Engine

The P.U.R.E. Corporation have released the first image of a 2014 F1 engine to René Fagnan of Canadian website Auto123.com; these will be all new 1.6l v6 turbo engines. New to F1, P.U.R.E. (Propulsion Universelle et Recuperation d’Energie) are a start up business created by Craig Pollock and backed by private investors. Initially based out of Mecachrome’s facilities, they are now based at the Toyota Motorsport Gmbh’s (TMG) Cologne technical facility. Seeking to exploit the new Engine rules as a route into F1, P.U.R.E. are speculatively developing their own engine, as they do not yet have a team announced as a partner to use the engine. Customers notwithstanding P.U.R.E. are a serious proposition, with Ex-Ferrari and FIA engineer Gilles Simon employed as Technical Director, as well as former Renault Sport MD Christian Contzen acting as a consultant. The engine’s design has been in progress since July 2011 by Simon and his team, mainly using simulation tools although single cylinder testing has also been carried out. With the move to TMG the engine’s major castings have been signed off and ordered, so that testing of a complete engine can be scheduled for July this year. Thereafter, a second generation engine will be ready for the summer of 2013.

In summary the 2014 engine rules mandate a 90-degree V6 engine of 1.6 litres, with a fixed crankshaft axis and chassis/gearbox mounting points. The engine can have a single turbo charger, which must be mounted along the cars centreline. Use of KERS is extended with a greater capacity for the Kinetic system (as used currently) as well as the introduction of a Thermal Energy Recovery System (TERS). Further green initiatives are caps on fuel flow and revs limited to 15,000rpm. Despite having a smaller cubic capacity and fuel allocation, the engine will produce the same maximum power as the current 2.4l V8 engines, albeit only when the Energy Recovery Systems are in use.

Completely unrelated to the technical side of the new regulations, is the Fans concern that the engines won’t sound very good. This is based around view that the engines have a relatively small capacity and additionally have the muffling effect of a turbo charger. This format being akin the WRC engines which do not have a pleasing engine note. But this disregards the F1 engines open exhaust, higher RPM and the aggressive use of the turbocharger itself.
Every engineer I’ve spoken to about the exhaust note has said they will sound good. Okay they are not going to be the same glorious sound of a V12, but they will be far from the dull sound of other small capacity turbocharged racing engines. I recall the sound of the original 1.5l turbo engines from the eighties; they revved far lower than the 2014 engine and still sounded loud and exciting.
Speaking to Auto123.com Gilles Simon commented on the engines sound “The sound of the V6 engine will of course be different. It’ll probably be a bit lower, but I really don’t think it’ll be unexciting for all that. The big turbine will be making a lot of noise, whistling really loudly. No, I the new cars won’t be boring at all”.

Engine Architecture

Looking at the P.U.R.E. CAD drawing we can see the basic layout of the engine and turbo installation; however we have to accept that this is a first public image and the detail of the installation may change. Indeed, Simon has described a different turbo installation at previous engine technology presentations. Having already seen images and some parts from the Mercedes AMG 2014 engine, I can confirm the P.U.R.E. installation appears to be similar to what the Brixworth factory has prepared.

What can be seen in this image are the engine block (grey), exhausts (brown), turbo-turbine (pink), turbo-compressor (blue), induction manifold (blue) and airbox (dark grey). Additionally the double camshafts (pink – exhaust blue – inlet) and the front chassis mounting plate (green) are visible. For clarity we are looking behind the engine, so the gearbox will mount to the face we can and the front of the engine mounts to the back of the monocoque.

Being of smaller displacement and less cylinders the engine is physically smaller than the outgoing engines. But the crankshaft axis is almost twice the height of the current engines, so overall engine height will be similar.

The turbocharger installation starts with the exhausts, the three exhaust branches joins with short primary pipes to the 3 way collector. This feeds a single secondary pipe leading to the turbochargers turbine. Unusually the turbine has two inlet feeds, one at the bottom for the left bank of cylinders and another at the top for the right bank of cylinders. This complicated the turbine design, but allows for much tidier exhaust routing. This will keep the exhaust gas velocity higher, so less power will be lost from the combustion chamber to the turbo. One detail to note is the convoluted sections of exhaust, to allow movement between the turbo and the exhaust preventing cracks forming in the exhaust.
In this image no wastegate or dump valves are visible, used to manage turbo lag by allowing the turbo to keep spinning when the driver is off throttle. With the TERS system its possible energy harvested from the turbocharger could be reused to keep the turbo spinning. Again we cannot see the TERS MGU in this CAD image. TERS will work via a similar method the KERS, a Motor Generator Unit (MGU) will harvest energy from the exhaust by sitting inline with the turbo charger shaft. Its will generate power from the spinning turbo and will be able to store and discharge that energy. In some cases the team will reuse the TERS energy into the main KERS boost (directly or via a battery) or reuse the TERS energy back into the turbo. In February’s issue of Race Engine Technology Magazine (RET), there was an interview with Simon by the Editor, Ian Bamsey. Simon commented to RET that P.U.R.E. will use TERS to pass power to the KERS MGU to power the engine. Using a battery as a buffer when too much energy is being harvesteddischarged.

Particularly relevant to recent F1 Aero design the exhaust will be a single outlet exiting from the centre of the top body. The rules still allow for two outlets, so perhaps a split in the exhaust and repositioning to gain some better aero effect could be adopted. However the 2014 rules were drafted before the current restrictions on exhaust position and will need to be rewritten to account for the central turbo charger regulation.

The turbo charger is mounted at the back of the engine, which will see it placed above the clutch and set partly inside the gearbox case. The second element of the turbocharger is the compressor; this sits head of the turbine. We can only see one outlet for the compressor, but it’s possible that the casing has two outlets as per the turbine. This will allow for two intercoolers, tidier packaging and critically a better balanced inlet manifold with a pressure feed for both banks.

At the IMIS show in Indianpolis, Simon showed another image of the engine. Simon explained to RET that the compressor may end up sitting ahead of the engine, with a shaft linking it to the turbine running through the engines “V”. This will keep the compressor in a cooler location and allow for even shorter, tidier pipework. Albeit at the expense of a longer and heavier turbine shaft, with potential torsional and inertia issues when the turbo spools up.

A sign that this CAD image is not a fully representative 2014 engine is the size of the compressor. In this image it is around the same size as the turbine, the Mercedes AMG compressor I saw was far larger, may be twice the diameter of the one shown here. Gilles Simon commented to Auto123.com “We’ll be using huge turbines that rev extremely quickly, up to 200,000 rpm”. Most likely these large diameter compressors will force some careful thought on their packaging into the chassis.
In this installation we can see the compressor outlet ends with a bare pipe and the inlet manifold has a corresponding open inlet. This will be for a sidepod mounted intercooler to cool the inlet charge. As fuel flow is limited, therefore revs or boost pressure will be relatively low. So it’s argued an intercooler may not be strictly necessary, as having one will extend the pipework to the detriment of turbo lag, also adding additional weight and aerodynamic drag. But for the P.U.R.E. example we see here, there is the option to have one fitted.
Having been used to normally aspirated (NA) engine and their airboxes, the inlet manifold looks very different, the two plenums are linked via smaller pipe, and their position is directly above the inlet valve. As the plenums do not rely on acoustic tuning as much as NA engines, their positioning is a little easier than with a NA airbox design. We can see fuel injection rails sticking quite wide out of the plenums; this doesn’t look suitable for aerodynamic packaging and will need to change before the unit is installed in a car.
Sitting between the inlet plenums is the airbox, this serves much more as a high pressure feed and filtration for the engine, than a NA airbox, which also serves as a tuning device for the induction process. We can see the filter which would fill the top of the airbox is huge and still be fed by a snorkel from the roll hoop as is used currently. Although the draw from turbo charger will ‘suck’ air from the inlet, the return to the aerodynamically better blade roll hoops may be an option for the team. As the better airbox tuning with a single inlet is no longer required. Again should the compressor be relocated to the front of the engine the airbox will be easier to package and will not be parked between the relatively hot induction plenums.

Even though the 2014 engine regulations are very prescriptive in a lot of the specification of the engine, we will some variation in turbo installations and the key factor will be in ‘energy management’. That is the power generated from the petrol, the KERS and the TERS to get the best laptime. Peak power will not be the critical factor, but how the energy is harvested and redeployed. Unfortunately this will be invisible to the fans and the engine suppliers aren’t likely to be very public about their Energy Recovery methods. So 2014 may be a hard year to the public to understand from a powertrain perspective.

Many thanks for P.U.R.E. and also Rene Fagnan of AUTO123.com for permission to use the image in this article.

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