KERS explained

A KERS or Kinetic Energy Recovery System was first tried in Formula 1 by McLaren  during its period of huge innovation way back in 1998.  But unfortunately it was banned almost immediately, the cars never raced with it and hybrid Formula 1 cars stayed little more than a concept until in 2008 it was announced that the systems would be made legal once more for the 2009 season. Only McLaren and Ferrari really got the best out of their systems and at the end of that year the F1 teams agreed amongst themselves not to use the technology in 2010. But for 2011 KERS was back and all but the three newest teams were using it.
In theory KERS makes F1 cars more environmentally friendly. They are devices used for converting some of the waste energy from the braking process into more useful types of energy which can then be used to give the cars a power boost (which is limited to six seconds a lap by the FIA).       
It all sounds very complicated but it really isn't, the basic physics of KERS is laid down in lessons taught to almost every secondary school child in the developed world. It is all based around Newtons basic principle which states that energy cannot be created or destroyed, but it can be endlessly converted. When you drive down the road your car has kinetic energy, when you brake that kinetic energy is mostly converted into heat energy (which is why fast cars need to keep their brakes cool). In most cars that heat energy is wasted, but in a KERS equipped car that is not the case. When the driver brakes most of the kinetic energy (or rotational force) is still converted to heat energy but a portion is treated differently and is stored up in the car.
When the driver presses his boost button that stored energy is converted back into kinetic energy and under the current F1 regulations gives the car about an extra 85bhp for six seconds. 

Kers Mercedes 

 Kers mercedes

There is more than one type of KERS, though currently in F1 only battery - electric is used. Most of these are based on a system supplied by Italian firm Magneti Marelli. This was the common system in F1, used by Red Bull, Toro Rosso, Ferrari, Renault and Toyota in 2009.
When the car brakes a proportion of the rotational force is captured by a electric motor / generator (MGU) mounted at one end of the engines crankshaft. This MGU converts the kinetic energy into electrical energy which is then stored in batteries. When the driver presses the boost button the electrical energy in the batteries powers the MGU - which puts an extra 85bhp into the engine.
The diagram below details the Marelli system and the picture above shows the Motor Generator Unit. Each team has a slightly different spec of MGU - all slightly smaller than the one pictured here but the construction principles are identical. McLaren and the Mercedes runners do not use the Marelli based system - rather they use KERS developed in collaboration with English firm Zytek Engineering, however it works on the same principles.

Kers diagram

 
One of the toughest elements of electronic KERS is how to store the electrical energy, most of the teams use a lithium battery, not dissimilar to those used in mobile phones (just a lot bigger). But just like the battery in your phone when you charge or discharge the battery gets hot so many of the KERS cars feature additional ducting to cool the systems. This is thought to be one of the main problems Red Bull has with the system on the RB7 which has its batteries in a hotter location compared with other cars on the gird.
BMW took a different approach in 2009 by using devices known as super-capacitors instead of batteries, these run cooler and are arguably more efficient. But the firm never got the system to work properly and then quit F1 taking the technology with it.
Williams approached the energy storage problem in a totally different way again, rather than fitting batteries or capacitors, they used a large flywheel. The system was fitted to a test car in 2009 but never ran publically. However the company developed a version of the system for long distance racing and now supplies it to Porsche which has employed it in a 911 Sports car. 
Fitting KERS to Formula 1 cars is meant to make the sport more relevant to the automobile manufacturing industry allowing teams to make forward steps in battery and motor technology which can then be fed directly into road cars of the future. In reality however the KERS regulations in F1 are really too restrictive for that to happen.
A number of non electrical systems have also been developed for F1, most notably the Flybrid, designed by former Renault F1 engine boss Jon Hilton. The system is based on a flywheel and operates totally differently from the Electronic and Williams systems. Honda trialled the technology back in 2008 but did not persue it. However at the 2011 Le Mans 24 Hours this solution was employed on a car and worked well.

Kers - Honda

 kers honda

 

Click here to see a clip on KERS and DRS


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