The Kinetic Energy Recovery System is a new technology used by the FIA ??in F1 racing cars, the English abbreviation KERS
KERS is the English abbreviation of Kinetic Energy Recovery Systems. The basic principle is to store the braking energy of the car body through technical means and release it as auxiliary power during the acceleration of the car! The specific usage method may be achieved by imitating the acceleration button of A1.
KERS systems with two technical principles and their advantages and disadvantages (the focus of this article)
Under the loose rules framework of the FIA, there are currently two KERS systems with technical principles under development: Flywheel kinetic energy recovery system and battery-motor kinetic energy recovery system. Below, we will introduce it in detail from five aspects: research and development background, technical principles, parameter indicators, technical difficulties, and solution advantages and disadvantages. First, let’s talk about the “flywheel kinetic energy recovery system” that has been launched.
A, R&D background
This is the technical solution that Renault will adopt, and Williams plans to buy it! In early 2007, with the support of Renault Automobile Company, two engineers of the Renault F1 Team, Jon Hilton and Doug Cross, left their headquarters in Enstone to form a company called "Flybrid Systems LLP" in Silverstone. company. Here, Flybrid is a combination of two English words flywheel and hybrid. We translate it as "Flywheel Hybrid System Company" Note: Hereinafter, it will be referred to as FB Company. The company developed a highly efficient flywheel kinetic energy recovery system in mid-2007 (see picture above).
The principle of the flywheel kinetic energy recovery system is actually very simple. Friends who played with pull-back toy cars as children know that when we roll the wheels backward to allow the energy storage structure (usually a spring or rubber band structure) to accumulate potential energy, and then place the car on the ground, the accumulated potential energy can make the car move quickly Get moving. FB Company's kinetic energy recovery plan adopts this basic principle. Note: It is the basic principle, that is, the conversion process from kinetic energy -> potential energy -> kinetic energy. But its specific working process must be much more complicated. You must know that this is an F1 car with a speed of more than 300 kilometers per hour. Let's take a look at its actual structure:
As shown in the picture above: This is the system schematic diagram provided by FB Company (the lower right is the CAD three-dimensional rendering). It is composed of: a set of high-speed flywheels, two sets of fixed transmission ratio gear sets, a CVT (continuously variable transmission) and a clutch (clutch 2). The continuously variable transmission is provided by technical partner Torotrak The company provides it, and another company, Xtrac, is responsible for manufacturing the transmission system. The working process of the system is as follows:
When the car is braking, the kinetic energy of the car body will be transmitted to the flywheel through the continuously variable transmission. At this time, the flywheel in the vacuum box is driven and rotates at high speed to accumulate energy. When the car exits a corner, the energy accumulated in the flywheel is released in the reverse direction through the continuously variable transmission. Note: The reverse here refers to the flow of energy, not the direction of rotation of the flywheel, and is transmitted between the output end of the main gearbox and the engine power. After merging, it is transmitted to the rear axle as a driving force. The entire system has a simple and compact structure and is controlled by a supporting program written in SECU (standard ECU). In terms of appearance, targeted adjustments can be made according to user needs. This means you can have different shape options!
C. Technical difficulties
As we all know, for F1 racing cars, every kilogram of mass is useful. In order to achieve the highest possible energy density ratio (note: this indicator of the flywheel kinetic energy recovery system is already very high) and minimize the impact of the system on the counterweight of the racing car, the flywheel kinetic energy recovery solution requires the main body of the energy storage flywheel. As small as possible, but how does this meet energy storage specifications?
The solution adopted by FB Company is to increase the rotation speed. At present, the speed of their trial flywheel has reached 64,500 rpm, which is an almost crazy number. But new problems arise at this time, because high speed means that the system will generate huge heat and face huge wind resistance losses.
Hilton and Cross ultimately decided to package the flywheel inside a vacuum box, which, according to the company, has an internal air pressure of up to 1x10-7 Pa.
What kind of concept is this? Jon Hilton said this is equivalent to one gas molecule having to travel 45 kilometers to meet another. But if you think about it, you have to do it. Placing the flywheel in a vacuum box can indeed solve the problems of heat generation and wind resistance loss, but how to prevent the air tightness of the bearing from being destroyed during the process of inputting and outputting power (to the flywheel)? A new problem is born again! Under the current technology, electrical conversion is an option, but the energy loss is too serious. As a result, the two engineers found a solution. They invented innovative shaft sealing technology and have now applied for a patent.
Now, the first commercial product is under development. Xtrac has obtained Torotrak’s patent authorization and will use the latter’s toroidal surface transmission scheme to develop efficient, compact, continuously variable speed ratio. The transmission device realizes the idea of ??kinetic energy recovery in F1 racing cars. And we can easily foresee that it will appear on ordinary road vehicles.