BMW Heaven - The BMW Knowledge Base - BMW options & electronic systems

Compound Brakes

Featured on all M cars, the big difference compared to conventional brake discs is that compound brake discs feature a radial anti-friction bearing for the brake disc ring. This floating system allows free thermal expansion of the brake disc rings, thus providing the option to use different materials with the best properties in each case for specific purposes. This, in turn, means that each component within the brake system is able to do a perfect job according to its specific requirements. The result is not only outstanding stopping power, but also a considerable reduction in weight versus conventional brake systems, a significantly higher standard of driving comfort and a much longer service life.

ConnectedDrive

ConnectedDrive is an innovative concept pioneered by the BMW Group. It ensures that all information, communication and assistance systems inside and outside the automobile are fully integrated with each other in a single network, thereby offering three advantages in the BMW 7 Series: safety, comfort and infotainment. BMW Assist, a telematics service, provides updates about current traffic conditions and traffic jam alerts. In the event of an emergency, the system pinpoints the automobile's location and automatically sends for help. The information service can also provide data about hotels, restaurants, etc. PCs and mobile phones can be networked with BMW automobiles as well.

Crash Sensor

In the event of an accident, the crash sensor activates the hazard warning flashers and overrides the centre lock function of the central locking, allowing the doors to be opened from outside in the interest of rapid help. The system also switches on the interior lights in the process.

Dynamic Brake Control

With DBC, when you need to stop in an emergency, the system reinforces your applying the brakes to provide maximum braking in the shortest distance. The criteria for full brake application are the speed with which you apply the brakes and the amount of brake pressure you exert. DBC is only activated when the brake pedal is depressed firmly and quickly. A brake pressure sensor records the magnitude and speed of the brake pressure change and the sensor communicates these values to the DBC control unit. The control unit compares the values to its stored DBC activation thresholds.

Digital Diesel Electronics

Digital diesel electronics (DDE) determines exactly when fuel injection is to start, as well as the volume of fuel supplied and charge pressure. This ensures unprecedented fine tuning under all running conditions. The result is even greater economy, improved smoothness and a reduction of harmful emissions. DDE are also responsible for speed regulation and start clearance after the change code has been checked along with the electronic immobiliser.

Differentiated Intake System

DISA is the abbreviation for Differentiated Intake System. The intake pipes are joined by a connecting valve that is closed at low engine speeds, but which guarantees impressive torque values because of the lengthy route the air has to take. At high engine speeds, the valve opens so that the air intake route is shortened, thereby increasing engine performance.

Fully-variable Intake System, DIVA

Alongside the valve train system Valvetronic, BMW's eight-cylinder engines possess another innovation that ensures they can adjust perfectly to the driver's power requirements: the fully-variable intake system, DIVA. It adapts the length of the intake manifold using a coiled regulation mechanism. Long intake travel provides high torque at low engine speeds, short intake travel helps to develop high power at high speeds.

Digital Motor Electronics

Digital Motor Electronics (DME) control, monitor and mastermind all central functions such as the car's ignition and fuel injection, as well as numerous ancillary functions such as the oxygen sensor. Collected information by sensors all over the car is assessed by a microcomputer which then regulates the ignition and fuel injection accordingly. The DME sensors monitor a large number of variables, including engine torque, air intake, the position of the choke valves or accelerator, etc. As a result, DME guarantees optimum power and performance at low fuel consumption and emission rates, as well delivering maximum reliability. The world's very first DME appeared in the BMW 732i in 1979.

Dynamic Stability Control

Dynamic Stability Control (DSC) incorporates a range of systems such as Dynamic Brake Control, traction mode (DTC) and ABS in order to correct instability as soon as it starts. Wheel rotation, longitudinal acceleration and the yaw rate are measured permanently, enabling the system to react when skidding threatens. DSC then adjusts engine power and applies braking as needed to ensure stability.

Dynamic Traction Control

DTC allows you to drive at the limits without fear of exceeding them. It increases wheel slip at the driven wheels in order to ensure optimum traction on any surface. This then allows the behaviour of the BMW to be controlled entirely by the driver, with the Dynamic Stability Control (DSC) system taking a back seat. Only in critical situations and at higher speeds does DSC intervene.

Dynamic Drive

Dynamic Drive is an active suspension control system offering an exceptionally high standard of lateral dynamic stability (body stability). This is provided by active anti-roll bars on the front and rear axles - active because rotating hydraulic elements referred to as actuators are integrated in the mechanical anti-roll bars. Incorporating two electronic pressure control valves, these actuators build up independent stability forces on the front and rear axle, minimising body sway when taking a bend. Dynamic Drive ensures supreme agility at all speeds, optimum steering and well-balanced load change behaviour.

Electronic Brakeforce Distribution

EBD optimises the performance of the car's ABS anti-lock braking system. ABS prevents an individual wheel from locking by cutting brake pressure as soon as a skid is detected. EBD takes this approach into another dimension. It can, for instance, adjust the braking force between the front and rear wheels to suit the car's load and road conditions, or brake the wheels on one side slightly harder than the other to maintain stability during a corner.

Electronic Damper Control

Electronic Damper Control (EDC) combines supreme driving comfort with similarly outstanding safety on the road. At the same time, the system consistently guarantees optimum vibration control regardless of the load the car is carrying. All measurements are permanently monitored by sensors and then evaluated by a microprocessor and commands are sent to the dampers, where solenoid valves serve to infinitely adjust damper forces to changing road, load and driving conditions. Furthermore, at the touch of a button the driver can choose the Sports program, making the suspension and dampers much firmer and more dynamic.

Electronic Differential Lock

The Electronic Differential Lock (EDL) applies brake force with the utmost precision to a rotating drive wheel up to a certain speed and then transfers the torque to the other wheel. An additional hydraulic pump is responsible for this transferral: if a pre-determined torque value for the wheels is exceeded, the pressure is rerouted via a magnetic valve to a faster-turning wheel, thereby braking it.

Electromechanical Parking Brake

The Electromechanical Parking Brake is an automatic handbrake. This sophisticated brake system offers two further benefits: Autostop and Hillhold. Autostop ensures that the car is automatically braked and held at a standstill when required: this means that the driver no longer has to keep their foot on the brake, as is the case on a conventional automatic transmission in order to prevent the usual "idling creep". Hillhold prevents the car from rolling downhill when starting on a gradient. With the engine running, all park braking processes are controlled by hydraulics via the Dynamic Stability Control (DSC) pump. When the engine is switched off, the same functions are controlled electromechanically via conventional bowden cables connected to the dual servo parking brake on the rear axle.

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September 08, 2008, 01:37:39 pm

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