Tech Facts of Moden-Day F-1 engines
With ten times the horse-power of a normal road car, a Formula On engine produces quite amazing performance. With around 900 moving parts, the engines are very complex and must operate at very high temperatures.
Engines are currently limited to 3 litre, normally aspirated with 10 cylinders. These engines produce approximately 900 - 850 bhp and are made from forged aluminium alloy, and they must have no more than five valves per cylinder. In a quest to reduce the internal inertia of the moving parts, some components have been manufactured from ceramics. These materials are very strong in the direction they need to be, but have a very low density meaning that it takes less force to accelerate them, ideal for reducing the fuel consumption and efficiency of the engine. A similar material, beryllium alloy has been used, but the safety of it has been questioned. This material has been banned for 2001. The following list outlines some facts about a modern day F1 engine:
Random Facts:
· In an F1 engine revving at 18,000 rpm, the piston will travel up and down 300 times a second.
· Maximum piston acceleration is approximately 7,000 g (humans pass out at 7-8 g) which puts a load of over 3 tons on each connecting rod.
· The piston only moves around 50 mm but will accelerate from 0 - 100 kmh and back to 0 again in around 0.0025 seconds.
· If a connecting rod let go of its piston at maximum engine speed, the piston would have enough energy to travel vertically over 100 metres.
- If a water hose were to blow off, the complete cooling system would empty in just over a second.
The 1998 Mercedes-Benz started the trend of developing a new breed of smaller and lighter engines. Modern engines have a mass less than 100 kilograms and are deigned to be as low as possible to reduce the overall centre of gravity of the car. The engine must be as light as possible, but also as stiff as possible. This is because the only thing connecting the rear of the car to the chassis is the engine, so it must be able to take the huge cornering loads fro the suspension and aerodynamic forces from the large rear wing. A BMW.Williams spokesman said that the engine is fixed to the chassis with only four high strength suds, and is connected to the gearbox with six of these studs. Renault Sport has begun what is set to be a new trend in engine design, opening up the V-angle beyond 100 degrees. This allows the engine to sit lower in the car, reducing the centre of gravity, but the unit is currently suffering problems due to vibration and lack of stiffness.
The engine usually contains around 18 pints of oil, but this can often be seen to be spread all over the track! About 12 pints will be within the crankcase and cylinders at one time, with a dry-sump lubrication system changing the oil within the engine about four times a minute. The oil used is a special synthetic oil that are designed to withstand the high stress and temperatures present in an F1 engine. Ingredients are carefully chosen to adjust the viscosity and friction characteristics to maximise the power output from the engine. The oils are constantly monitored by their manufacturers by X-Ray Fluorescence (XRF) to ensure that there is no build up of metals in the oil, indicating the onset of possible engine failure. The oils are designed to last around 400 km before being changed, compared to around 20,000 km for a road car.
WHAT MAKES THESE ENGINES DIFFERENT FROM ROAD CAR ENGINES?
You can often see road cars with engines larger than three litres, but these don't produce upwards of 750 bhp. So how do F1 engineers produce this amount of power from this size of engine? There are many differences between racing and road car engines that contribute to the large power difference.
F1 engines are designed to rev much higher than road units. Having double the revs should double the power output as there are twice as many engine cycles within a certain time. Unfortunately, as the revs increase, so does friction within the engine, so eventually, a point is reached where maximum power will occur, regardless of the number of revs. Running engines at high revs also increases the probability of mechanical failure as the components within the engines are being more highly stressed.
Exotic materials such as ceramics as mentioned earlier are employed to reduce the weight and strength of the engine. A limit of what materials can be used has been introduced to keep costs down, so only metal based (ferrous) materials can be used for the crankshaft and cams. Exotic materials can reduce the weight, and are often less susceptible to expansion with heat, but there can be draw backs. Incorporating these materials next to ferrous materials can cause problems. An exotic material such as carbon fibre will not expand as much as steel for example, so having these together in an engine would ruin the engine, as they run to such small tolerances. Although only 5% of the engine is built of such materials (compared with roughly 1/3 rd Steel, 2/3 rds Aluminium) they still make a worthwhile addition to power output.
EXHAUSTS
Exhausts are important to remove the waste gases from the engine, but they also play a part in determining the actual power of the engine. Due to the complicated harmonics within the engine, exhaust length can directly alter the power characteristics as pressure waves flow through the exhaust and back to the engine. Making sure these pulses are in time with the engine will enable more air to be sucked into the engine, hence more power. In 1998, Ferrari introduced exhausts that exited through the top of the engine cover above the gearbox (These are commonly called periscope exhausts due to their shape). Previously, all teams had the exhausts exiting through the diffuser, but this could alter the amount of downforce developed depending on whether the driver was on the throttle or not. Most teams have now copied the design, apart from McLaren, Williams and BAR. Cars that use the periscope exhausts often have gold or silver film protecting the suspension and lower rear wing from the high temperatures of the exhausts gases. Michael Schumacher retired from the 2000 Monaco GP because the heat from the exhausts cracked his suspension, so effectively protecting the suspension from this heat is crucial.
Exhausts also play a critical role in determining the shape of the rear of the car. If the engine designers can make the exhausts as compact as possible, it allows the 'Coke Bottle' shaped part of the car to start nearer the front of the sidepods, increasing the efficiency of the rear aerodynamics.
AIRBOX
Just above the driver's head there is a large opening 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 air-box does the opposite. Between the air-box and the engine there is a carbon fibre duct that gradually widens out as it approaches the engine. As the volume increases, it causes the air flow slow down, raising the pressure of the air which pushes it into the engine. The shape of this must be carefully designed to both fill all cylinders equally and not harm the exterior aerodynamics of the engine cover.