Mmm, there’s a question! They just stop the car don’t they – no problem, surely?
Our blog considers this question in more depth, and finds out that there is a lot more to the technology of how brakes work to stop a car and bring you to a safe stationary position. Our technical experts at ŠKODA were asked to explain it all.
The mechanical components of the vehicle braking system include the disc brakes and pads to slow and stop the wheels, and the drum brakes to hold the handbrake. Pads attached to the brake calipers squeeze against the disc to slow down and stop the vehicle. The bigger the vehicle, the greater the tonnage they have to stop; and the legal minimum stopping distance needs to be considered when manufacturers safety test a vehicle.
It may seem an obvious question. So far, so good, nothing much has changed in the mechanical respect over the years. However, vehicles can travel faster, with greater power and better aerodynamics than ever before. There is more traffic on the road than 20 or 30 years ago and so the ability to control speed and emergency stop your vehicle suddenly becomes a key feature in road user safety.
Our ŠKODA Technical Department has given us an insight into how the factory develops and tests the brake and control systems.
The current ŠKODA Octavia, for example, is designed to stop from 100km per hour down to zero within 34 metres. This is helped by modern tyres which transfer the braking effect onto the road surface. Brake tuning and calibration needs to consider the driver’s ease of use, driving style and the passengers’ safety and comfort.
Every driver wears down the brakes a little differently – it’s like shoes, some people wear the heels, others the edges. Some drivers brake at the last minute, others use engine braking* to slow down gradually (putting less pressure and therefore less wear on the brakes). If you need to stop quickly, don’t be afraid to slam on the brakes as full engagement gives you the shortest stopping distance. Anti-lock braking systems (ABS) and electronic stability program (ESP) brake control systems help keep the car under control. ESP works with ABS, traction control and steering to keep the vehicle under control.
Brake designers strive to achieve the right ‘brake intensity curve’ – that is, making sure that the effect of braking increases in strength smoothly as the brake is pressed. Also, that the brake behavioural characteristics remain the same across the ŠKODA range – so that if you change from a Fabia to a larger model, such as a Kodiaq, you will be able to operate the brakes with the same ease.
The brakes should also work the same way in all circumstances, so, for example, if driving on a bumpy surface nothing in the system should become separated. Brake design is regulated by testing of brake integrity on repeated braking, mountain descent and ESP stability testing. Materials used for brakes are limited by legislation too – asbestos is not allowed, neither is ammonia, lead, cadmium or copper. So, brake design is a complex and highly specialised skill.
Parking brakes have also developed over the years, now becoming mostly electronically controlled. The classic handbrake system uses a lever that tensions a cable via rods and extends the brake calliper piston, via a worm gear, to press the pad against the disc. Releasing the cable reverses the process. Drum brakes also work like this. Electronically controlled parking brakes use a push button to cause an electric motor to push a piston out through a special small gear box, also containing a worm drive.
What else must today’s ŠKODA brake developers consider? The weight of the vehicle, passengers and luggage; towing weight; wheel size; engine power; fuel economy; noise levels and particulate emissions to name but a few.
Prototypes developed under test conditions and on computer models require testing in practical conditions and any vibration or noise needs to be minimised. Resistance to corrosion is also key. The ultimate solution according to Michal Klofec, ŠKODA’s Brake System & Control Coordinator, is the use of ceramic discs, but this is an unaffordable technology for vehicle mass production.
With electric cars in production and future models planned, new options have to be considered. Recuperative braking helps with storage of energy to power the car battery. Electric cars tend to be heavier than cars with internal combustion engines due to the battery weight. Therefore, electric cars have drum brakes on the rear axle. Electric cars have a rear drive axle and recuperative braking takes place here, with corrosion less likely.
An active cooling system for the brakes is a final key consideration. Air can be fed in via ducts in the bumper, but this can increase air resistance, reduce aerodynamic ability and so increase fuel consumption. ŠKODA came up with a solution to use the engine radiator fan, which can detect if more intensive cooling is needed and so direct air via special grilles underneath the car, therefore not affecting the aerodynamics.
Michal Klofec recommends having your brakes checked as part of regular servicing by our expert Technicians. Electronic parking brakes need specialist diagnostic service equipment and brake fluid can evaporate over time, so needs topping up every couple of years. Letting the experts check all these things and maintaining regular servicing is crucial to keep the brake system in good working order.
And finally, did you know?
The electronic “handbrake” also has a special feature that many drivers aren’t aware of. In an emergency, pulling it (the button has to be held for a few seconds) activates emergency braking mode, which can be used if the main brakes fail or if the driver is suddenly incapacitated – this mode can be activated by the person in the passenger seat, if necessary. Holding the button activates a special ESP mode that pressurises the braking circuit to gradually slow down and stop the car. The button does not control the parking brake at that moment, but serves as a means of telling the car’s electronics that something unusual is happening and the car needs to come to a halt.
Wow! So braking is a bit more complex than we thought then! Thanks to brilliant engineers like Michal’s team, all these aspects are considered carefully to develop a safe vehicle packed with modern technology.
If you're looking for a quality vehicle with up-to-the-minute safety features and driver assistance systems, look no further than our JCB Group brands. To keep your braking system in good working order, book online for a vehicle health check, service or MOT. Don't forget to check your tyres too.
*Engine braking means going down the gears gradually to let the engine slow you down, not the brakes – coming up to a roundabout for example – allowing plenty of time to stop smoothly and with control.
