Connected between the flywheel and the continuously variable transmission of the Flybrid, mechanical KERS is an epicyclic gear system, the focus of this article.
Epicyclic gearing is a gear system that consists of one or more planet gears, rotating about a central sun gear. Typically, the planet gears are mounted on a movable arm or carrier which itself may rotate relative to the sun gear. Epicyclic gearing systems may also incorporate the use of Read more…
The continuously variable transmission (CVT) as used by Flybrid, is mounted between two clutches within the KERS unit. The clutches allow for disengagement of the CVT from the flywheel and the vehicle when not in use, and therefore minimises losses.
The only mechanism for controlling energy into or out of the flywheel is by controlling the ratio of the CVT. The CVT is responsible for the smooth variation of ratios. The CVT may sometimes be referred to as a Toroidal Continuously Variable Transmission
The use of a flywheel as an energy storage device is not new. The conventional heavy, metal flywheel as connected to the crankshaft of an internal combustion engine, is used as an energy storage device, releasing its energy in order to maintain momentum during the idle strokes of the engine. The mechanical KERS system has been made successful by producing a flywheel of low mass, small size, running at high speeds.
The energy stored in a flywheel is given by the following formula: Read more…
KINETIC ENERGY RECOVERY SYSTEM (KERS) EXPLAINED
KERS is a collection of parts which takes some of the kinetic energy of a vehicle under deceleration, stores this energy and then releases this stored energy back into the drive train of the vehicle, providing a power boost to that vehicle. For the driver, it is like having two power sources at his disposal, one of the power sources is the engine while the other is the stored kinetic energy. Read more…
Having looked last month at the McLaren Mercedes KERS system, this month we will investigate the use of energy recovery systems in La Sarthe, the home of the Le Mans 24 Hours.
The ACO (Automobile Club d’Ouest, organisers of the Le Mans 24 Hours) currently incorporate the following section into the technical regulations for LMP1 cars in the ALMS and at Le Mans itself (see end of feature).
KERS is currently only utilised in an ACO sanctioned series Read more…
The veil of secrecy which has surrounded Formula One’s most successful KERS system was partially lifted recently when Zytek Automotive were unveiled as motor and power electronics supplier for the Formula One KERS system as fitted to the 2.4 litre Mercedes-Benz FO 108W V8 engine.
The KERS system was developed and brought up to racing standard in 24 months by Mercedes-Benz High Performance Engines in collaboration with Daimler / Mercedes-Benz Research & Development. Read more…
RET recently attended the 2009 UK Formula Student competition at the Silverstone circuit in Northamptonshire.
Of the total 87 teams from 16 countries, seven were in Class 1A, of which four were from the UK. Class 1A is the competition’s low carbon category. Teams are encouraged to use green technology and alternative fuels to reduce their CO2 emissions. In an additional challenge, the teams calculate the CO2 and energy that are used during manufacture of the car. Teams compete in all dynamic and static events but are judged on their car’s Read more…
Television coverage of this years Formula One races has captured some textbook examples of a KERS equipped driver out accelerating a conventionally powered car on the straight. And yet, as mid-season approaches no KERS equipped car has won a Formula One race, or set pole position, and only two teams are still running with it, the rest having either rejected its use or never planned to run it in the first place
Despite the promise that kinetic energy recovery has offered in Formula One, even several races into the new season very few teams are choosing to race it. And, of those that are, the favoured solution seems to be based on a motor/generator for energy transfer and batteries as a storage medium. Both Ferrari and Renault have taken this route while McLaren, which is being tight lipped on the matter, certainly has such a system and may well be using it. In the battle to optimize all the variables, weight distribution seems to have been the main driver in this choice. The freedom to place the batteries low down and far forward is beneficial to car balance and this is where most of the ballast that the KERS system will be replacing normally sits.
Given current Formula One Kinetic Energy Recovery System (KERS) rules for Formula One, teams have found that the centre of gravity height and weight distribution penalty is less when employing batteries as the storage medium rather than a flywheel. Nevertheless, in future seasons, when the rules are modified so that the amount of energy that can be recovered is greater the required battery weight will increase disproportionately and it is likely that the balance will tip in favour of flywheels. Read more…
