BMW Z22 points to the future
BY GAUTAM SHARMA | 16th Aug 2000
The Z22 Mechatronic (mechanical system with electronic control) car dispenses with mechanical steering and hydraulic brakes in favour of "steer-by-wire" and "brake-by-wire".
It also features an innovative horizontally divided body which separates into a "functional" chassis frame and passenger cell.
This solves the conflicting goals of comfort and lightweight design by using a new carbon-fibre technology which is nearly ready for production.
BMW says the Z22 has fuel consumption of just 6.0-litres/100km during normal driving conditions, yet it is claimed to offer the performance, comfort and interior space of a 528i wagon.
Powered by a four-cylinder engine mounted transversely ahead of the rear axle, the Z22 combines the wheelbase of a 7 Series with the turning circle of a 5 Series.
Without mechanical components such as the steering column and parts of the foot pedal mechanism, passive safety and comfort are increased.
BMW also points out that conventional mechanical steering has a fixed gear ratio which compromises agility, stability and comfort.
The electro-mechanical steering is said to eliminate these compromises, making parking easier as well as promoting a greater feeling of stability at high speeds.
The "brake-by-wire" system means functions such as ABS, CBC, DSC and DBC can be exclusively contained in the central controller.
In addition to reducing stopping distances, the system features an automatic parking brake on all four wheels and an adjustable pedal module.
Furthermore, brake-by-wire provides dynamic distribution of the brake force. For instance, when braking in a curve more retardation can be applied to the outside wheels to promote greater stability.
The concept car also dispenses with conventional instruments in favour of a head-up display that projects primary information such as speed, car position, warning lights and fluid level indicators or navigational instructions on to the windscreen.
The specially shaped multi-function steering wheel and a central operator control element in place of today's gearshift, known as the Man-Machine-Interface (MMI), are all that is needed for the entire operation.
By using the assigned push buttons on the multi-functional steering wheel, the driver can change gears with the steptronic, use the cruise control and horn as well as set the foot pedals and head-up display.
The central MMI comprises a six-position rotary switch and a keypad.
To start the engine the driver has to place his finger on the rotary switch, which in turn uses the fingerprint to determine if he is authorised to drive.
The rotary switch is also used to start the motor and select the program for the CVT drive. The keypad behind the rotary switch contains keys for the parking brake and four-way flashers.
Other innovations include:
* Intelligent light technology: Comprises the curve light (illuminates around corners) and intersection light (provides a broader spread of light). The flat construction tail-lights are constructed using optical fibre technology for the white reversing lights and LED technology for the remaining tail-light functions. The interior lighting uses fibre-optic rods and cables.
* Cameras instead of mirrors: Exterior mirrors and the interior rear-view mirror have been replaced by cameras. By using image processing, a single panoramic image is created out of the three individual images and is shown on a display in the place of the interior rear-view mirror. This eliminates the blind spot.