Formula One Engines

The F1 engine is the most complex car of a current Formula One car. It consists of close to 5000 parts of which around 1500 are moving elements. When all of these elements are fixed together after 2 weeks of work it it can produce more than 750hp and reach more than 20,000 rpm. At its maximum pace the current V8 engines consume around 60 litres of petrol for 100km of racing.

While manufacturers could easily continue to develop better engines within the 2006 regulations, the FIA ruled that this unnecessary cost was to be ruled out as it introduced an engine freeze as of the 2007 Formula One season. Instead of a yearly 20 to 30hp gain, the manufacturers cannot further develop their engines and are imposed a rev limit of 19,000 rpm.

At the end of 2005, the last season where the regulations allowed 3litre engines with 10 cylinders, some engines were producing more than 980hp and running very close to the 1000hp mark, a figure that was never reached since the ban on turbo engines. It was a sign for F1's governing body to change the regulations as top speeds at Monza of 370km/h were deemed hazardous for the drivers as well as the spectators.

In 2004, Renault released a small videoclip of their engine at work on the dyno. You can find it here.

At the moment, all f1 engines can produce around 720 hp with 8 cilinders in a 90 degree V-angle. The limitation of 19000 rpm as of 2007 however limits that performance a bit further.and. These engines are mainly made from forged aluminium alloy, because of the weight advantages it gives in comparison to steel. Other materials would maybe give some extra advantages, but to limit costs, the FIA has forbidden non-ferro materials.

It's not exactly known how much oil such a top engine contains, but this oil is for 70% in the engine, while the other 30% is in a dry-sump lubrication system that changes oil within the engine three to four times a minute.

Difference with road engines

• Higher volumetric efficiency. VE is used to describe the amount of fuel/air in the cylinder in relation to regular atmospheric air. If the cylinder is filled with fuel/air at atmospheric pressure, then the engine is said to have 100% volumetric efficiency. On the other hand, turbo chargers increase the pressure entering the cylinder, giving the engine a volumetric efficiency greater than 100%. However, if the cylinder is pulling in a vacuum, then the engine has less than 100% volumetric efficiency. Normally aspirated engines typically run anywhere between 80% and 100% VE. So now, when you read that a certain manifold and cam combination tested out to have a 95% VE, you will know that the higher the number, the more power the engine can produce. Bacause turbos are not allowed in F1, this item does not differ that much from a normal road engine.
• Unfortunately, from the total fuel energy that is put into the cylinders, everagely less than 1/3 ends up as useable horsepower. Ignition timing, thermal coatings, plug location and chamber design all affect the thermal efficiency (TE). Low compression street engines may have a TE of approximately 0.26. A racing engine may have a TE of approximately 0.34. This seemingly small difference results in a difference of about 30% (0.34 - 0.26 / 0.26) more horsepower than before.
• From all that power generated, part of it is used by the engine to run itself. The left over power is what you would measure on a dynamometer. The difference between what you would measure on the dyno and the workable power in the cylinder is the mechanical efficiency (ME). Mechanical efficiency is affected by rocker friction, bearing friction, piston skirt area, and other moving parts, but it is also dependent on the engine's RPM. The greater the RPM, the more power it takes to turn the engine. This means limiting internal engine friction can generate a large surplus in horsepower, and where in F1 the stress is on power, on the road it is also on fuel consumption.

These main optimization necessities are what causes the engineer's headaches. At the end of the line, an F1 engine revs much higher than road units, hence limiting the lifetime of such a power source. It is especially the mechanical efficiency that causes Formula One engines to be made of different materials. These are necessary to decrease internal friction and the overall weight of the engine, but more importantly, limit the weight of internal parts, e.g. of the valves, which should be as light as possible to allow incredibly fast movement of more than 300 movements up and down a second (this at 18.000 rpm).

Another deciding point trying to reach a maximum of power out of an engine is the exhaust. The minor change of lenght or form of an exhaust can influence the horsepowers drastically. It is both for performance and cost limitations that the FIA do not permit variable outlet systems in Formula One.

Engine design

Considering internal combustion engines (thus leaving out oscillating and Wankel rotary combustion engines), there are basically three different ways of building an engine. The difference here is how the cylinders are placed compared to each other.

• Inline engines, where all cylinders are placed next to (or after) each other are not used in Formula One since the 60's. While the engines are small, they are long and therefore require a heavy cranckshaft.
• Boxer engines are actually one of the best ways to build an engine, if all external factors allow it. Two cylinder rows are placed opposed to each other. You could consider a boxer engine as being a 180° V-angle engine design. These engines became popular in F1 because of the low centre of gravity and the average production costs, but later on disappeared out of the picture as this type of engine is not sufficiently stiff enough to whitstand the car's G-forces in cornering conditions. Ferrari for instance have run 12 cylinder boxer engines from 1970 to 1980 before moving to a 120° V-angle engine.
• V-type engines, as currently used in all F1 cars. The V is in fact the geometrical angle that seperated the two cylinder banks from each other where the crankshaft can be considered the origin of the angle. Obviously for this type of engine the size of the V is a major factor and must be decided in the first phases of the engine design. Previously, engines have been designed with angles such as 60° V12 or 72° V10. Although it has historically been an interesting evolution to see the differences between the teams' engines, the FIA have fixed the engine type to 90° V8 models.

Since the introduction of the Ford Cosworth DFV, an engine in a F1 car is a stressed member of the chassis, meaning that it is an integral part of the car. Before that idea, a chassis was built as a tube frame with the engine placed in it afterwards, while now a chassis would fall apart if no engine was fitted. A current engine is bolted in between the monocoque at the front and the gearbox in the back of the car. A boxer engine's dimensions and the lack of strength would compromise the weight of the chassis and limit possibilities for the aerodynamicists to design an optimal body. The same goes for the inline engines as they are small and long.

As a result every manufacturer moved to a V-angle engine, even before it was set as a requirement in the regulations. It is however vital that the precise angle is chosen wisely in order to build a powerful engine. The size of the V angle has to do with firing sequence and primary balance. A circle has 360 degrees and the (included V angle x the number of cylinders) must be a function of 720 (one rotation of the crankshaft is 360 degrees and every combustion cycle takes two turns - intake and combustion phase) in order to achieve evenly spaced cylinder firing and primary balance. That is why a boxer engine is an ideal layout. The cylinders are opposed at 180 degrees so having 2 or 4 or 6 or 8 or 10 or 12 isn't that big a deal. Perfect primary balance is easy to achieve, as long as the reciprocating and rotating parts are in balance and, the firing order is always evenly spaced. A few examples make it clear why several specific angles have been very popular in F1 engine design:

• As mentioned earlier, Ferrari have used a 60° V12 or 120° V12 engine. As for the first option, divide 720° by 12 cylinders and you get 60. You get 120° when you imagine a V12 as two aligned V6 engines.
• Renault's extremely successful 72° V10 engines share the same thoughts. It is the perfect bank angle for any V10 engine if a boxer is not an option. One cylinder is fired every time the cranckshaft has completed 72° so that after 2 turns every single piston has gone through one complete cycle.
• Currently every team runs 90° V8 engines but not only because the regulations prescribe so. Also this is a perfect angle and meets the size requirements set by the aerodynamicists.
• Contrary to these optimal choices, there have also been unusual uses. For instance the 2005 90° V10 engines that everyone but Renault were using. While they may have been more interesting for other reasons, it's performance could theoretically not beat Renault's RS25 that was a 72° V10. The 90° V10 engines hence had either offset crankpins or a funny firing order.
• Before their RS25 Renault was trying a revolutionary design as they designed a 112° V10. Although the engine evolved from RS21 to RS23 and was beneficial in terms of the centre of gravity it was finally abandoned. The engine could not reach competitively high rpms since the uneven firing order introduced unwanted vibrations in the engine.

Cranckshaft design

Although the V8 with the now compulsory cylinder angle of 90 degrees may look like a sawn-off V10, technically it is an entirely separate concept with its own specific requirements. The V8 has a distinct firing sequence and demands a fundamentally different crankshaft design. Whereas a 72-degree offset crankshaft was used in most V10 Formula One engines (e.g. BMW) , V8 powerplants can feature crankshafts with either four throws spaced at 90 degrees or four throws spaced at 180 degrees. Standard production engines are fitted with 90-degree crankshaft variants due to their better dynamic attributes, but a 180-degree crankshaft is favoured in racing car engine design. The improved performance this allows offsets the disadvantages in terms of dynamics.

Cooling

Just above the driver's head there is an air inlet that supplies the engine with air. It is commonly thought that the purpose of this is to 'ram' air into the engine like a supercharger, but the airbox does the opposite. Between the airbox and the engine there is a carbon-fibre duct (1) that gradually widens out as it approaches the engine. As the volume increases, it makes the air flow slow down. The shape of this must be carefullly designed to both fill all cylinders equally and not harm the exterior aerodynaimcs of the engine cover, this all to optimize the volumetric efficiency.

The following picture displays the uncovered rear part of the championship winning Renault R25. The element marked with (1) is the airbox that guides air into the engine (2) to be mixed with fuel in the cylinders. If is therefore not an aid for cooling but simply a requirement for the engine to function.

Secondly, the flat panels located nearly vertically in the front of the side pods are the radiators (4). While in this picture the radiator is covered with a protective hose, it is not during running as air passes through the aluminium fins of the radiator to cool down the engine coolant and oil. The position can vary a lot and it dependent on the team's ideas for the outer shape of the sidepod.

Marked with (3) is the engine exhaust system while (5) and (6) identify the rear suspension that is fitted on the gearbox.

Transmission

The transmission of any car is considered to be all intermediate gears and systems to get the engine rotational power to the wheels. In Formula One this is a vital part of the car, not only because of the high power of the engine. All transmission elements are joined together into the gearbox which is located in a critical area for the car, both strengthwise as aerodynamically. More can be found in the specific article about F1 transmissions.

Engine development

The last years of engine development before the engine freeze were mainly focused on power output and overall engine weight while the V-angle and other important characteristics were left untouched. The incredible quest for weight reduction started with Ford Cosworth that was able to produce an engine at least 25 kg lighter than any other. Although they suffered some reliability problems troughout the season, the engine was an example for the others, as it allowed teams to shift some weight in the car. That could be placed more on the front wheels or on the rear wheels which could help the steering or the acceleration of the car.

In this race to decrease engine weight, the 1998 Mercedes-benz engine was possibly one of the most revolutionary engines ever built. Two years later Mercedes was again revolutionising engine design by the use of Berillium alloys which gave the engine a potential to rev higher than any other at the time. However, since Berillium is poisonous when used in high percentages, the FIA changed the regulations to limit Berillium only up to 5% of mass in an alloy. As of that moment, Mercedes had been struggling badly to build a new engine that could meet the performance of the at that time mighty Ferrari and BMW engines.

As the FIA eventually also banned variable inlet systems that were used until the end of 2005 the engine developers did not have much choice but to reduce weight of the moving components of the engines to gain performance.

As this research costed tons for a marginal gain of around 25hp a year, restrictions were further imposed by fixing the bank angle and setting new limits on the weight and centre of gravity. In fact when the engineers had to build a V8 engine for 2006 it was required to be 95kg, heavier than their V10 engines used in 2005.

Regulations

The current regulations on Formula One engines look like this. These specifications have become more strict during recent years in an attempt to limit costs and decrease performance. You can find an evolution of the most important regulations per era in the safety section. As this is only an exerpt of the most important regulations on engines, you would need to see the official FIA technical regulations before you start to design a Formula One engine yourself.