Tuesday, April 9, 2013

Lotus and Mercedes - Is their FRIC passive suspension the next big thing?

The Adrian Newey designed WIlliams FW14, FW14B and FW15 were all design masterpieces, which apart from being very aerodynamically efficient, also incorporated clever devices such as semi automatic gearboxes, anti-lock brakes, traction control and the most important of all, active suspension. These devices, once perfected, ensured that Williams won back to back championships in 1992 and 1993 at the hands of Nigel Mansell and Alain Prost. But in 1993 active suspension was deemed illegal and could not be used any further.

                                


Active suspension basically controlled the vertical movement of the wheels with an onboard computer by keeping the tires perpendicular to the road in corners, allowing better traction and control. The onboard computer detected body movement from sensors throughout the vehicle and, using data calculated by complex math, it controlled the action of the suspension system. A passive system is one where the movement of the suspension is determined by the surface of the roads and body roll or pitch variation of the car effected during cornering, accelerating and braking.

A car without the active suspension device would pitch forward under braking and experience the opposite effect while accelerating. While cornering the front inside wheel of the car lightens and more load is put on the front outside wheel (load is on the left wheel while cornering to the right and vice versa). It also allowed the car to maintain a stable ride height allowing all the aero devices like wings and turning vanes to function as they were designed to.

A view of the system on the Mercedes
Lotus and Mercedes have been running and developing a passive suspension system since 2011, which in effect, gives them a similar result, but without any illegal device on board. The rules state that there cannot be any device on the cars that can be moved actively (by a driver or a computer) to provide any aero benefit (except the DRS rear wing).

The FRIC (Front and Read Inter-Connected) system hydraulically links the front and rear suspension. This system in effect links all 4 suspension corners of the car to pipes carrying hydraulic fluid which moves around based on the laws of physics. It allows the car to maintain a constant ride height at all four corners of the car to ensure that :

  • The contact patch of the tyres stays constant, allowing the driver to have the largest possible contact patch with the asphalt underneath, providing him with the best grip the tyres can around corners and it will also prevent or minimise uneven tyre wear.
  • The work done in the wind tunnel by the aero guys is not lost in the corners due to the roll and pitch of the car. Since Formula 1 cars today are so aerodynamically efficient and are tuned to channel air from the front nose tip all the way through to the back of the car to maximise downforce, these changes in the height of the car due to roll and pitch make the car the car lose downforce and it is thus unsettled. The FRIC system prevents the roll and pitch and therefore maintains the flow of air all around the car and thus maintains downforce.

We would expect to see an arms race, because a device like this, if perfected gives that team an edge that would be tough to overcome before the end of the year. It will be interesting to see if Red Bull and Ferrari can incorporate such a device, as it would be tough to, unless it has been built into the design of the car. Maybe they already do and we haven't heard about it yet. Watch out for this space.

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