The driver chooses a preferred speed according to the scale markings on the speedometer – in 5 km/h (3.11 mph) steps from 30 to 80 km/h (18.64 to 49.71 mph), or 10 km/h (6.21 mph) steps at higher speeds. The selected speed is shown by light-emitting diodes on the speedometer scale; the system’s status (on/off – vehicle detected) can be seen on the center display. You can select the time lapse between the vehicle in front and your own car in four stages, between 1 and 2.3 seconds; the chosen value can be seen in the driver information system.
The system’s dynamic response can be varied by choosing one of three drive programs at the MMI (dynamic/standard/comfort). The system then accelerates the car or slows it down at the dynamic rate chosen by the driver. The ‘comfort’ setting is limited to a maximum speed reduction rate of 3 m/s2.
Lane monitoring and collision warning – Audi braking guard The Audi braking guard is an extra safety function that is part of ACC. If there is a risk of colliding with the vehicle in front, the system warns the driver in two stages: at first with an ‘early warning’ gong accompanied by a visual signal on the instrument panel. At this point the ESP increases hydraulic pressure in the brake system as a safety precaution, so that if the driver brakes, full stopping power is available immediately.
If the driver fails to respond and the risk is still present, the system builds up pressure rapidly in the brake circuits. This sudden braking action only slows the car down slightly, but nonetheless causes it to suffer a noticeable jolt. The aim of this jolt, which Audi has investigated in an extensive series of tests and found to be very effective, is to draw the driver’s attention to the need for urgent action. If the driver now applies the brakes, full braking power is available without any delay, and even hesitant pressure on the brake pedal causes the hydraulic brake assistant (HBA) to make a full brake application.
The Audi braking guard is still monitoring the situation when ACC is deactivated. On the other hand, either the early warning signal or the complete Audi braking guard function can be switched off at the MMI, to comply with the Audi policy of always leaving the driver in control of the situation to the extent that they may wish.
Looking back and to the side: Audi side assist
Audi side assist also makes use of intelligent radar technology. The system was designed to warn drivers of dangerous situations when changing lanes. Two radar sensors located in the rear bumper operate at 24 GHz, monitoring a space of up to 50 meters (164.04 feet) in width to the side and rear of the new Audi A4. A highspeed computer analyzes the data.
Any time another vehicle going roughly the same speed moves into the blind spot or a vehicle approaches rapidly from behind, a yellow LED display lights up in the housing of either the left or right exterior mirror and remains lit. This warning signal is designed to be unobtrusive so as not to disturb. Drivers do not see it unless they are looking directly in the mirror.
The LEDs brighten and begin flashing rapidly for roughly one second if, despite the initial warning signal, the driver signals a lane change. A series of tests conducted by Audi has shown that this flashing light is nearly impossible to overlook, because the human eye is extremely sensitive to changes in contrast in its peripheral vision.
This visual display is located on the inner surface of the mirror housing so that the driver is virtually the only one who can see it. The brightness of the display adapts to the surrounding light and can also be adjusted from the MMI operating terminal. The system is activated at speeds greater than 60 km/h (37.28 mph) and can be deactivated by pressing a button.
The APS systems: parking made easy
Audi has two available parking assistance systems for the new A4 that make parking easy. The familiar, successful Audi parking system (APS) uses an audible signal to indicate distance to the rear. Audi parking system with camera integrates a rearview camera display. Incorporated into the trunk lid and extremely sensitive to light, this camera contains a fish-eye lens providing a generous, 130-degree view of the area behind the car. The images generated by this camera are equalized and displayed on the MMI operating system monitor. The system also guides the driver with a variety of suggested lines and fields. In addition to real-time mode, APS advanced also offers the classic features of a visual/acoustic parking aid, aided by ultrasound sensing technology.
The Audi A4 also is raising the bar in its class in one of the most exciting of cutting-edge technologies – multimedia. It is being launched with an attractive array of communication and entertainment technologies.
The AMI (Audi Music Interface) makes it possible to hook up a fourth generation iPod, while a separate adapter cable allows users to connect any audio player of their choice having a USB 2.0 interface. The AMI software is modular in design, with individually stored drivers responsible for communicating with players and reading their protocols. New driver updates can be installed quickly and easily anytime a new player comes onto the market.
The concert and symphony radios operate with a dual tuner: two tuners process signals before these proceed to a digital processor. One of the tuners processes music while the other works in the background, scanning for stations that are clear enough to receive. This technology can pull in even the weakest of stations, because it can combine its receivers in such a way that the two antennas of the A4 operate like a beam antenna.
MMI: Navigation system and luxury user interface
North American customers have an optional navigation system that offers a dual tuner and seven-inch color display. Navigation information is provided by a fast, powerful DVD drive. An AMI (Audi music interface) interface for full iPod integration within the MMI system is available.
Audi offers two excellent sound systems for its concert and symphony radio systems: 180 watts of system power and 10 speakers give the Audi sound system impressive, well-balanced surround sound. In addition to the eight standard speakers, this system also includes a center speaker in the instrument panel and a 260 mm (10.23 inch) subwoofer in the rear shelf. An extensive variety of settings are available for customizing the systems.
Pure delight: The Bang & Olufsen sound system
The pinnacle of sound system technology and acoustics, Bang & Olufsen – once available only in the A8 luxury sedan – now can bring pure listening pleasure to A4 drivers. Brilliant sound quality, faithful resolution, precise staging and a broad, finely differentiated frequency spectrum – the product of the Danish sound specialists will meet every demand.
Audi and Bang & Olufsen have come together as partners in pursuit of the same objectives. Both companies place a premium on the most modern technology available, intuitive operation and classic, technoid design. Furthermore, both manufacturers are experts when it comes to materials, quality craftsmanship and working with aluminum (which Bang & Olufsen uses in its speaker covers). The heart of the Bang & Olufsen sound system is a 505W amplifier that digitally processes signals according to a proprietary surround-sound algorithm, guaranteeing pure listening satisfaction for everyone in the car. The numerous settings options include four different sound modes. Included in the system is a microphone for analyzing the noise level within the A4; the system then changes the frequency, adapting the signal output to ambient sound conditions.
The Bang & Olufsen sound system includes 10 active channels with 14 speakers. Two three-way systems are found in the front (each including one speaker in the door, mirror triangle and instrument panel); two speakers are located in each rear door. The acoustic choreography is rounded out by a center speaker in the instrument panel, a 260 mm (10.23 inch) subwoofer in the spare wheel well and two surround-sound speakers.