Diffuser (automotive)
As the diffuser is called in motorsport effective areas under the floor of a race car to improve aerodynamics by a suction effect. The diffuser ensures by its asymmetric shape for a pressure distribution in the subsoil and thus output.
Operation
Measurements show that reduced the horizontal bottom to the diffuser while driving a small area at the transition air pressure is created. From both sides, air flows there under the vehicle and paired forms vortices that flow in opposite rotation through diffuser.
Diffusers are the least understood areas of racing cars and have been the subject of many experiments in aerodynamics until at least their effect chain was measured and recorded. Early evidence of the contact pressure appeared around 1980, but details of the flow were not known until two decades later. The side air entering and the impetus of their rotation is a substantial cause of the effect. This is in contrast to other designs with ground effect, which date back to the Lotus 78 and looking to minimize side air exchange. A diffuser loses under such conditions largely the desired effect and gains on the other hand, if tail in front of the vehicle to initiate the vortex. The maximum lead angle of the diffuser is about 15 °, because otherwise a stall occurs, and its effect is prevented. The optimum length of the diffuser is half the length of the vehicle.
Front diffuser
In front diffuser guide vanes under the front spoiler the air flow side behind the front wheel arches upwards. Applications can be found at prototypes and group CN vehicles.
Rear diffuser
In Formula 1, the use of a diffuser technical restrictions of the FIA subject. By the diffuser can underperform use the slipstream following vehicles. The diffuser was up to the rule change in 2009 with up to 70 percent - with a share of 10 percent of the total air resistance - involved in the overall output of the Formula 1 racing car. The vehicles advised by him in air turbulence, which reduce the pressure. In order to reduce the impact of the diffusers turbulence behind the car and so to facilitate driving in the slipstream and thus overtaking, the FIA fit for Formula 1 2009 season to the requirements for sub-floor. In Article 3.12.7 of the official technical regulations it now says: " No visible from under the car body member, which is up to 350 mm behind the Hinterachslinie may be higher than 175 mm. " With this change the existing diffusers were in their design and thus cut their effect, the proportion of total output still was about 40 percent thereafter.
Double diffuser
The so-called double diffuser at the Formula 1 race cars of Brawn GP ( Brawn BGP 001), Williams ( Williams FW31 ), and Toyota ( Toyota TF109 ) installed in the 2009 season, first, increased the pressure by a second shorter shelf above the actual diffuser. The double diffuser of the Brawn BGP 001 was also due from the bottom is not visible central channel, which generated higher output and thus more traction over simple diffusers.
The possibility of such an interpretation of the rules already existed before, but was only brought to the rule change in 2009 to the reduction of the diffusers a real advantage. As in the winter tests, the advantages of the three equipped with double diffusers team was well ahead of the 2009 season, the discussion about the legality began. The teams Ferrari, BMW Sauber, Renault and Red Bull set them before the first race in Australia protest against the double diffusers installed a. However, the competent race stewards rejected the protest and declared the diffusers in compliance. The protesting teams went against this decision on appeal, but the FIA Court of Appeal endorsed the stewards in its decision of 15 April 2009, and explained the double diffusers have ultimate responsibility for legal. At the Grand Prix of China, a few days after the decision of the FIA , McLaren and Renault went with modified diffusers at the start, the rest of the team moved to new developments. In March 2008, suggested Ross Brawn, Team Principal of Honda F1 at that time to make the diffuser regulations easier and more precise. To Formula 1 2011 season of the double diffuser was banned.
Triple diffuser
Toyota developed in the 2009 season from the double diffuser a triple diffuser in his model Toyota TF109.
In the blown diffuser
To Formula 1 2010 season was invented by Red Bull Racing the ' blown in diffuser ". At the Red Bull RB6 race car, the hot exhaust gases were directed to the diffuser roof.
Gallery
A Porsche 962 ...
Top of a diffuser tunnel of a Porsche 956