| July 5, 2011
Chassis
Source: Audi of America
The Audi Q3 brings more sportiness to the compact premium SUV class. Its balanced chassis combines agile handling, supreme safety and great comfort. The best place to experience its qualities is on winding country roads – the precision with which the car responds to the steering input and the stability with which it takes corners. The responsive suspension smoothes out all types of uneven road surfaces with ease. The steering provides precise feedback, a taut, precise steering feel and composed, quiet tracking.
Very sophisticated: the suspension
The front wheel suspension has a track width of 1,571 millimeters (61.85 in) and follows a classic design. It is a McPherson strut construction with lower wishbones of forged aluminum. The subframe to which they are mounted is made of a chill-cast lightweight alloy, which has a favorable effect on the distribution of weight between the front and rear axles. This figure is roughly 58 to 42 percent. The subframe is rigidly bolted to the body, which further enhances its rigidity.
The electromechanical rack-and-pinion steering impresses with high efficiency. Because it consumes no energy when driving straight ahead, it reduces fuel consumption by as much as 0.3 liters per 100 kilometers. It has a direct steering ratio of 16.4:1, and steering boost gradually decreases with increasing speed.
The steering is networked with a variety of sensors and driver assistance systems on board the Q3. This tight networking enables the steering to work closely together with the optional Audi active lane assist and the park assist systems.
The four-link rear axle of the Audi Q3 has a track width of 1,575 millimeters (62.01 in). Its trailing links absorb the propulsive and braking forces. Its bearings are rather large for a more comfortable ride. On the other hand, the three wishbones per wheel are attached very rigidly to the steel subframe for optimum handling characteristics. Large rubber-metal bearings connect the subframe to the body.
The links of the rear axle are made of high-strength grades of steel, and the wheel carriers are cast aluminum. The shock absorbers and the compact coil springs are separate from one another, which benefits cargo area volume. Stabilizer bars are used at the front and rear axles.
Thanks to a generous 17 centimeters (6.69 in) of ground clearance, the Q3 handles rough terrain with ease. Upon request, Audi equips the Q3 with the S line sport suspension with tauter springs, dampers and bearings. It lowers the body by 20 millimeters (0.79 in).
Four driving modes: Audi drive select
The Q3 is available with optional Audi drive select driving dynamics system – a software module in the central control unit (gateway) where all of the bus systems come together. At the push of a button, the driver can decide at any time how he or she would like to drive the compact SUV – in the comfortable “Comfort” mode, the balanced “Auto” mode or the sporty “Dynamic” mode. In the fourth mode, “Efficiency,” all components including the cruise control and air conditioning are optimized for fuel consumption. All adjustments are made harmoniously so that they make their presence known to the driver but do not irritate.
Audi drive select alters the characteristics of the electronic gas pedal and the electromechanical power steering. The S tronic, adaptive light and the optional active damper control can also be integrated into the system.
The CES dampers (CES: continuously controlled electronic suspension) are managed by a fast computer. Supplied with a large amount of data, it manages the suspension’s function as appropriate for the condition of the road, the driver’s style and the mode selected in Audi drive select.
The heart of the CES dampers is an electronically controlled valve that steplessly varies the flow of oil. The positioning time is just a few milliseconds. A large cross-section provides for a soft, comfortable ride. During sporty driving, hard braking or sudden avoidance maneuvers, on the other hand, the valve impedes the flow and the Q3 is intimately connected to the road. The steering response becomes even more precise, and the specific stabilization of each wheel makes the self-steering behavior even more neutral and safe.
The Audi Q3 rolls off the assembly line with size 6.5 J x 16 forged alloy wheels with a seven-arm design and 215/65 tires. Models with the two top-of-the-line engines come standard with 7 J x 17, ten-spoke wheels and 235/55 tires.
18-inch wheels in a variety of designs are available as options from Audi, and quattro GmbH offers 8.5 J x 19 wheels with 255/40 tires.
All tires are characterized by low rolling resistance, including the optional winter and all-season tires. Audi offers an optional tire pressure indicator. A repair kit comes standard; a space-saving spare tire is available as an option.
The brake system is an excellent match with the sporty character of the compact SUV. The pedal feel is spontaneous and firm, enabling the driver to precisely meter the response. With all engine versions, the front discs are vented and measure 312 mm (12.28 in) in diameter; the solid rear discs have a diameter of 282 mm (11.10 in). The electromechanical parking brake is integrated into the rear brake system. It also serves as an emergency brake, if necessary.
All-new: ESP
The ESP stabilization system in the Audi Q3 is a complete new development. When braking on surfaces with different coefficients of friction, it prevents the car from pulling to one side. If a skid is imminent, it supports corrections that defuse the situation. Some of its functions have been specially tailored for the compact SUV. One of these is the rollover prevention function, which uses fast interventions with strong braking at the wheel to prevent the inside wheel in a curve from possibly lifting up during extreme driving maneuvers.
The ESP also includes trailer stabilization and a dry braking function. The latter periodically cleans the brake discs of moisture and dirt to prevent fade in wet conditions.
Another high-end feature of the ESP is the electronic limited slip differential. In the front-wheel drive Q3, it interacts with the front axle as opposed to both axles in the quattro versions. When data from multiple input signals indicate to the control unit that the powered inside wheel in a curve is relieved too much, it initiates a small and precise brake intervention there. The intervention causes excess torque to flow to the outside wheel.
At the same time, the difference between the drive forces generates a certain yaw moment that helps the driver by turning the car very slightly into the corner. Self-steering behavior remains neutral longer, and handling becomes more precise, agile and stable.
All Audi Q3 models are equipped with hill hold assist, which uses the electromechanical parking brake. It maintains the brake pressure for a brief time after the driver steps off of the brake pedal. Still to come is hill-descent assist, which maintains a constant speed while going downhill of between 10 and 20 km/h (6.21 and 12.43 mph), depending on the surface.
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