[eltel]

For those who relish this stuff, this fragment of a recently published article explains some of the workings behind the buzzwords of EBC, CDC, etc. I know that a lot of this is already available elsewhere, but there are a lot of new MINI owners who may like to catch up on this stuff. Hope it's of use to someone out there. I certainly got something from it.



MINI Technical Features

The structure of the new millennium MINI sets new safety standards for a vehicle of its size and price in the 21st century.

Using the most advanced development methods, such as virtual crash simulation, the MINI’s engineers have succeeded in giving the car structure a standard of body stiffness 2–3 times greater than other models of its size. Together with the highly advanced and precise suspension, this is one of the key factors for the go-kart-like driving feeling offering the driver an essential driving experience.

Developed to the high standards of the BMW Group, the level of engineering of the MINI’s chassis and suspension is uncompromising in every respect.

For example, the multi-arm rear axle is unique to the MINI, giving the rear wheels optimum kinematics, together with the greatest possible luggage space. The McPherson strut front axle is also highly space efficient.

Equal length front drive shafts - normally found only on large front-wheel-drive cars - neutralise front-wheel-drive ‘tugging’ when accelerating and braking.

Large disc brakes (vented at the front) are supplemented by standard four-sensor ABS with CBC Cornering Brake Control and EBD Electronic Brake Force Distribution, giving the MINI optimum brake power. ASC+T traction control, which assists the driver at the limits of tyre adhesion, is standard on Cooper S models and optional on MINI Cooper.

MINI sets safety standards

Uncompromising safety was given top priority in developing the MINI Cooper.

A safety concept reflecting the absolute state of the art and setting new standards in the compact car segment was one of the highlights in the specifications for the MINI. This was implemented in full accordance with the BMW Group’s strict quality and production standard.

Combined with the latest braking and stability technology developed by the BMW Group, the MINI gives its driver the best possible opportunity to avoid potentially hazardous situations.

Active safety

The MINI comes as standard with disc brakes on all four wheels, with the front discs vented for extra efficiency. The disc dimensions are 276 x 22 mm at the front and 259 x 10 mm at the rear. The brake system in diagonal twin-circuit arrangement comes as standard with four-sensor ABS, electronic brake force distribution (EBD) and Cornering Brake Control (CBC).

EBD (Electronic Brakeforce Distribution)

EBD controls the distribution of hydraulic brake forces between the front and rear wheels, thus allowing optimum use also of the rear wheel brakes. Whenever the rear axle of the car is heavily loaded, there is roughly as much weight when applying the brakes on the rear wheels as on the front wheels. This allows the rear wheels to safely build up a high level of brake force, optimising the car’s braking behaviour.

Conversely, when the car is carrying only a small load, the rear wheels reach their friction limit and start to lose grip much earlier than the front wheels. This is where the EBD system cuts in automatically above a medium level of brake pressure, long before ABS interacts. The system remains in use at all times and cannot be deactivated by the driver.

CBC Cornering Brake Control

CBC Cornering Brake Control, which optimises rear-wheel brake performance without affecting tracking stability, is also standard on MINI Cooper and Cooper S models.

Whenever the driver applies the brakes, for example in a series of fast bends, the car may start to swerve and subsequently oversteer even under low brake pressure. Applying a special computer simulation model, CBC is able to determine lateral acceleration from the signals emitted by the four ABS sensors. CBC thus ‘sees’ the bend and builds up brake pressure faster on the front outer wheel than on the other wheels. This counteracts any inclination of the car to spin.

ASC+T Traction Control

Driver switchable ASC+T traction control is also standard on MINI Cooper S and optional on MINI Cooper. ASC+T prevents the front wheels from spinning from a standstill, even under adverse conditions. This keeps the driver in control of his car even when the wheels have varying grip and prevents the wheels from locking should there be a change in road surface. The system activates a dashboard warning light to warn the driver of wheelspin, regardless of whether ASC+T is activated or not.

DSC Dynamic Stability Control

DSC Dynamic Stability Control is also available as an option on both MINI Cooper and MINI Cooper S models as an extension of ABS and ASC+T. DSC monitors not only longitudinal forces, but also the lateral forces acting on the car.

In addition to the ABS speed sensors on the wheels, DSC uses further systems to measure the pressure in the brake cylinder (determining in this way whether and how the driver is applying the brakes), the steering wheel lock (in order to determine the direction and the lane chosen by the driver) and lateral acceleration acting on the car.

DSC is therefore in a position to detect the driver’s intentions and the current motion of the car, sensing whether the vehicle is deviating critically from the desired direction of travel. It intervenes by varying the brake forces acting on the individual wheels and changing engine torque through the engine control unit.

In this way the system counteracts unstable driving conditions possibly caused by accelerating, applying the brakes, driving round bends or suddenly experiencing a change in load – that is conditions which may lead to over- or understeer.

When oversteering, the DSC control unit applies the brake on the outer front wheel. If the driver is already braking, the computer increases brake pressure on this wheel and reduces brake pressure on the wheels facing to the inside of the bend. When understeering, the DSC control unit applies the brake on the inner wheel in a bend, at the same time reducing brake pressure on the outer wheels.

Tyre Puncture Indicator

The MINI Cooper is the first car of its size and type to be fitted as standard with a tyre puncture indicator. This enables the driver to respond to a loss in pressure before the tyre is damaged or any kind of danger can arise.

The system is based on a simple principle. When it loses pressure, the tyre changes its rolling radius and its circumference, thus rotating at a higher speed. The system measures wheel speed through the sensors on the four-sensor ABS unit, comparing the wheels diagonally together with their average speed and thus recognising any loss of pressure. The indicator then warns the driver via a lamp in the speedometer.

All MINIs now come with 16-inch light alloy wheels with standard run-flat tyres – another unique feature for a car of this price.

These tyres feature reinforced sidewalls and a heat-resistant rubber compound, allowing functions such as ABS, traction control or Dynamic Stability Control to remain fully operative even if these tyres suffer a loss of pressure.

The tyres allow the car to be driven carefully for up to 150 km at a speed of up to 80 km/h until the tyre can be repaired.

Passive safety

The MINI also sets new standards of passive safety with the standard fitting of six airbags.

As well as front and side airbags to protect the driver and front seat passenger, Australian MINI Cooper and Cooper S models are also fitted with the AHPS 2 = Advanced Head Protection System and housed within the roof lining along the side panel, offering both front and rear occupants maximum protection from head injury.

The foundation for this benchmark level of passive safety is the carefully designed and coordinated bodyshell structure, with body stiffness 2–3 times greater than on comparable models. This also means less body vibration and, as a result, lower noise.

Should the worst come to the worst, the MINI again sets new standards. Body components absorbing energy in the event of an impact have been developed according to BMW Group principles. The transverse mounted engine ensures optimum performance in a crash, while the front axle also takes up energy passed on through the floorpan. The long wheelbase, low centre of gravity and minimal unsprung weight introduce a new level of roadholding and handling for a vehicle of its size.

Drivetrain

When Sir Alec Issigonis presented the Mini in 1959, the car was a genuine revolution in automotive design and engineering.

The original Mini was the first car in the world with its engine fitted crosswise at the front and with the gearbox beneath the engine.

This provided a lot more space at the front end of the car, enabling Issigonis to reach his ambitious objective of building a small family sedan with space for four adults. And at the same time he created the first small car able to drive like a sports car.

The new interpretation of the original now takes up this concept consistently and authentically, carrying it into the present and the future – the MINI is a small and compact car with front-wheel drive and excellent driving characteristics.

With its very low centre of gravity, the car’s weight distribution is 63 per cent and 37 per cent on the rear wheels. This offers the MINI Cooper two benefits in one: First, the front end of the car has sufficient weight on the road in the interest of excellent traction; second, the weight distribution between the front and rear wheels, excellent for a front-wheel-drive vehicle, ensures outstanding driving characteristics on the road. These benefits are then further enhanced by the stiff body structure, the multi-arm rear axle and EHPAS steering.

The transmission, coolant pump and air conditioning compressor are bolted directly on to the engine block, thus making optimum use of the compact engine bay. The result is maximum space for the car’s crumple zones.