Modes and their effects

This chapter describes the effects of the individual modes in the drive and dynamic driving systems. As the individual systems are switched over together in a coordinated manner, this lends coherence to the overall behavior of the vehicle. This of course also means that meaningless combinations, such as a sports accelerator pedal characteristic combined with a highly comfort-oriented automatic gearbox shift program, are avoided and meaningful combinations for the mode are integrated instead.

This is why when compared to earlier vehicles, the configuration of individual systems can to a great extent now be uncompromisingly tailored to one mode. The driver therefore not only experiences coherent vehicle response characteristics in all modes, he/she will also sense the differences between the individual modes far more acutely.

The table below demonstrates this, particularly through the comparison between the "Normal" and "Sport" modes.

	Comfort	Normal	Sport	Sport+
Drive systems
Accelerator pedal characteristic	Normal	Normal	Sports	Sports
Shift program, automatic gearbox	Normal	Normal	Sports	Sports
Shift speed, automatic gearbox	Normal	Normal	Sports	Sports
Chassis and dynamic driving systems
Power steering assistance	Normal	Normal	Sports	Sports
Integral Active Steering	Normal	Normal	Sports	Sports
Dynamic Stability Control	DSC on	DSC on	DSC on	DTC (sports)
Vertical Dynamics Control	Comfortable	Normal	Sports	Sports
Active anti-roll bar	Normal	Normal	Sports	Sports
The configuration shown here in "Sport" mode applies for both drive and dynamic driving systems.

If the "Comfort" and "Normal" modes are compared instead, it is evident that the configuration differs in one dynamic driving system only: the Vertical Dynamics Control. This characteristic of the "Comfort" mode does not happen by chance and takes several peripheral factors into account:

• Most drive and dynamic driving systems ensure that driving is sufficiently comfortable in the "Normal" configuration; this is something that BMW 7 Series customers would expect. The Servotronic already offers requirement-based power steering assistance with maximum comfort, for example.
• The "Normal" configuration does not necessarily mean adherence to a single, defined system characteristic. The shift program of the automatic gearbox is only one example of how the current driving condition and driver's command are taken into account in order to bring the behavior of the relevant system into line with these requirements.
• Most drivers relate a desire for greater comfort with the suspension and damping characteristics. This requirement is particularly relevant when driving on poor or uneven roads.

This means that the "Comfort" mode also embraces the philosophy of driving dynamics control which is to achieve a coherent vehicle response characteristic that meets the expectations of the driver.

The "Sport" and "Sport+" modes also differ in terms of the coordination of one specific dynamic driving system: the Dynamic Stability Control. In the "Sport" mode, a decidedly sports-oriented overall vehicle behavior is available to the driver.

Although it is assumed that many drivers would like to use this "Sport" mode, the DSC remains in normal operating mode and stabilizes the vehicle in a timely manner as required. The familiar intervention thresholds (slip, sideslip angle) that the driver has become accustomed to in the "Comfort" and "Normal" modes remain unchanged. This ensures that less proficient drivers are not taken by surprise when the DTC subsequently intervenes in the sportier DTC mode.

Only once a proficient driver deliberately selects the second sports mode "Sport+" will gentle drifts also become available due to the higher wheel slip and sideslip angle.

The two additional modes that the driver can select using the DTC button produce the effects on the drive and dynamic driving systems shown below.

	Normal	Traction	DSC off
Drive systems
Accelerator pedal characteristic	Normal	Normal	Normal
Shift program, automatic gearbox	Normal	Normal	Sports
Shift speed, automatic gearbox	Normal	Normal	Sports
Chassis and dynamic driving systems
Power steering assistance	Normal	Normal	Sports
Integral Active Steering	Normal	Normal	Sports
Dynamic Stability Control	DSC on	DTC	DSC off
Vertical Dynamics Control	Normal	Normal	Sports
Active anti-roll bar	Normal	Normal	Sports

The "Traction" mode is similar to the familiar DTC mode of the DSC in former BMW vehicles. All other drive and dynamic driving systems remain in their normal configuration which makes its main application clear: the purpose of "Traction" mode is to improve traction, e. g. when driving off on a loose subsurface. Sports driving takes a background role instead as the "Sport+" and "Sport" modes are available for this.

The stabilizing DSC interventions are switched off in the "DSC off" mode. Only the braking interventions that support traction are performed i. e. Electronic Differential Lock Control.

In this case, most other drive and dynamic driving systems are in the sports configuration. This means that the aim of "DSC off" mode is to support pure driving; a direct bond between the driver, vehicle and road.

Although initially it may seem astonishing that the accelerator pedal characteristic remains in the normal configuration in both "Traction" and "DSC off" modes, this setting is deliberate. When driving off on a loose subsurface and also when driving in a highly sports-oriented manner with the DSC switched off, it is especially important that the driver can apply engine torque extremely sensitively. This is much easier to do using a normal rather than a more sports-oriented accelerator pedal characteristic.

The sports-oriented accelerator pedal characteristic translates the accelerator pedal angle into a higher torque requirement at the engine. This torque requirement is then also put into effect more quickly by the engine control system.

As a result, the driver perceives the response characteristics of the drive, and therefore the vehicle, as more sports-oriented. However, the driver cannot use this to apply engine torque sensitively.