The new Audi A4 Avant will be available with a choice of two TFSI delivering maximum power of between 110 kW (150 hp) and 185 kW (252 hp). Compared with the previous model, their fuel consumption has been reduced by 10 percent.
The TFSI engines
The entry-level gasoline engine is the 1.4 TFSI. The compact four-cylinder with displacement of 1,395 cc, has a maximum output of 110 kW (150 hp) and torque of 250 Nm between 1,500 and 3,500 rpm. In combination with the seven-speed S tronic transmission, it accelerates the Audi A4 Avant from 0 to 100 km/h in just 8.9 seconds and on to a top speed of 210 km/h (130.5 mph). With its aluminum crankcase, the new four-cylinder engine weighs just over 100 kilograms, despite its highly complex technology package. The 1.4 TFSI with S tronic consumes only 5.6L per 100 kilometers, resulting in CO2 emissions of 129 grams per kilometer.
The 2.0 TFSI is available with a displacement of 1,984 cc. In the high-end version, the 2.0 TFSI delivers 185 kW (252 hp) and torque of 370 Nm. This allows sporty driving: The new Audi A4 Avant with quattro drive and seven-speed S tronic sprints from 0 to 100 km/h in 6 seconds and has an electronically limited top speed of 250 km/h.
These results are based on a new strategy – Audi continues to develop its successful engine downsizing into rightsizing. The pioneering efficiency of the 2.0 TFSI is the result of an innovative combustion method whereby the comparatively large engine displacement is not a handicap, but a prerequisite.
With a moderate driving style, customers of new Audi A4 Avant experience the economical advantages of a small engine, but do not feel its disadvantages when driving in a more sporty manner.
The new combustion method with shorter compression and longer expansion phases as well as increased compression is designed especially for partial load, by far the most common mode of operation. The intake valves close much earlier than usual; in connection with increased pressure in the intake manifold, this reduces throttling losses during aspiration.
Due to the shortened compression phase, the compression ratio was successfully increased from 9.6:1 to 11.7:1. This means that in the compression phase, the engine only has to compress as much gas as a 1.4 TFSI. Also in the expansion phase, in which it fully utilizes its two liters of displacement, it profits from the high compression ratio; the resulting higher level of pressure during combustion further increases the engine’s efficiency.
In order for the fuel-air mixture to swirl sufficiently despite the short intake time, the combustion chambers, piston recesses, intake ducts and turbocharging of the new 2.0 TFSI are specially adapted to the new combustion method. Under higher loads, the Audi valvelift system opens the intake valves later, resulting in a higher charge, which ensures good power and torque delivery. Injection pressure has been increased to 250 bar.
S tronic, front-wheel and quattro drive – there are various solutions for power transmission in the new A4 models. Tailored technology is available for each engine.
Audi’s new seven-speed S tronic is available for all engines . The dual-clutch transmission, which replaces the continuously variable multitronic transmission, features excellent efficiency. The most important improvements are a further reduction in friction, the low weight, highly efficient oil lines and a centrifugal pendulum-type absorber on the dual-mass flywheel which allows very low idling speeds.
The two compact multi-disc clutches of the new seven-speed S tronic are arranged axially behind each other instead of – as with the predecessor – radially above each other, which reduces drag torque. They operate two separate subtransmissions, which are constructed like manual transmissions. They are permanently active but only one of them is connected to the engine. Gear shifts take place within a few hundredths of a second by means of clutch operations, and with virtually no interruption of traction. With the quattro transmissions, power is transmitted from the drive shaft through a spur-gear stage to the front-axle differential.
The S tronic is integrated into the engine’s thermal management and designed for start-stop operation. The driver can select between modes D, S and E and can manually shift gears at any time with the selector lever or with the standard shift paddles on the steering wheel. All the driver’s inputs are transmitted to the transmission electrically (“by wire”), a quick tap on the selector lever triggers the shift command.
The new cruise control includes an impressive efficiency function: When the driver lifts his or her foot from the accelerator pedal in mode D or E, the transmission shifts to freewheeling whenever that would result in fuel savings. This coasting mode is possible between 55 and 160 km/h).
With the gasoline engines, quattro permanent all-wheel drive is available for the 2.0 TFSI with 185 kW (245 bhp).
Audi’s quattro all-wheel drive is the ultimate in terms of dynamics, traction, safety and straight-line reliability. It is a purely mechanical system and therefore operates without any delay. In normal operation, its self-locking central differential, which is designed as a planetary gear train, transfers 60 percent of the engine’s torque to the rear axle and 40 percent to the front.
Depending on the situation, up to 70 percent of the torque can be transferred to the front and up to 85 percent to the rear. These high limits allow a clearly defined torque distribution and extremely precise interaction with the control systems.
The further developed wheel-selective torque control is a drivetrain “partner” and is now active on all road surfaces. During dynamic cornering, the software function slightly brakes the front wheel on the inner side of the curve (with frontwheel drive) or both inner wheels (with quattro drive) before wheelspin occurs. This also takes place when the drier is not pressing the accelerator. Due to the different forces, the car turns slightly into the curve; the roll-steer effect remains neutral for longer and the car’s handling is more precise, agile and stable.
The new Audi A4 Avant blends great talents: dynamic handling and a comfortable ride approaching the level of the next higher automobile category. The Audi engineers developed a new suspension system for this model series with a focus on systematic lightweight construction and precise responses.
A further enhanced five-link front axle is used, the principle of which allows optimal absorption of longitudinal or lateral forces. The mounts are designed to be stiff and sporty in the lateral direction but smooth and soft in the longitudinal direction. Vibrations are consistently eliminated with the use of a hydromount, which ensures excellent comfort along with a high degree of agility.
In order to achieve optimal stiffness, the upper links are integrated directly into the bodywork, unlike on the previous model. All axle links, the pivot bearing and the damper stilts are made of forged aluminum. The lightweight concept is completed with the use of monotube dampers and high-strength, thin-wall tubular stabilizer bars and segmented wheel hubs. Compared with the previous model, the weight of the front axle has been reduced by six kilograms.
The lower link level is attached with newly designed rubber mounts to a hybrid subframe made of high-strength and aluminum. The stiff installation of the subframe in the front of the body minimizes vibrations and provides the foundation for optimal agility.
Audi also decided on all-new electromechanical power steering, saving 3.5 kilograms compared with the previous model. It consumes very little energy and has a direct, sporty ratio of 15.9:1. Power assistance is based on the car’s current speed. The steering provides very exact feedback from the road, responds spontaneously and is very precise. The new electromechanical power steering is functionally connected with some of the optional new driver assistance systems such as the Stop&Go adaptive cruise control.
Dynamic steering is optionally available in combination with engines of 110 kW (150 hp) and above. Through the use of superimposed gearing, its ratio varies by up to 100 percent, depending on the car’s speed and the mode selected in the Audi drive select driving dynamics system. Vehicle stabilization is supported by lightning-fast steering impulses, further enhancing stability and safety.
In the rear of the new Audi A4 Avant, a five-link axle replaces the trapezoidal-link axles of the previous model. By means of an intelligent combination of materials, the weight of the axle components has been reduced by another five kilograms.
Low unsprung mass provides a sporty driving experience, and together with the new damper and elastomer tuning, it allows a smooth ride, excellent body control and improved wheel damping and control. For the first time, monotube shock absorbers have been used, resulting in a further weight reduction. The axle is insulated from the body with hydraulically damped axle mounts. This reduces the shocks from the road surface significantly while maintaining lateral guidance. Additional measures for the reduction of fuel consumption are frictionoptimized wheel bearings and aero-deflectors that reduce roll and wind resistance.
A central suspension control system has been applied to achieve ideal interaction between the various driving dynamics systems. This highly integrated control device was specially developed for the new A4. It processes all the information relevant for driving dynamics, from which it calculates the driving situation and the current road surface frictional coefficient. This information allows optimal control of the system for highly precise, dynamic handling and maximum ride comfort.
As an alternative to the standard tuning with highly sensitive monotube shock absorbers, Audi has equipped the new Audi A4 Avant with two suspension systems that utilize variable damping; one focuses on comfort and the other on sporty driving. Sensors measure the movement of all four wheels as well as longitudinal and transverse acceleration. The shock absorbers are then adjusted to the road-surface conditions and driving situation accordingly. This results in enhanced driving dynamics with even more comfort. In addition, the driver can choose the basic suspension setting by pressing a button in Audi drive select, so that the desired characteristics are always available.
This is made possible with newly developed CDC (continuous damping control) shock absorbers with electromagnetically controlled valves in their pistons. They allow hydraulic fluid to flow faster or more slowly as required. A new operating concept makes them very energy efficient. The central suspension control unit processes all sensor signals within milliseconds and controls each shock absorber individually.
Together with the wide range of the damper valves, this ensures a wide spectrum between a soft rise and firm handling. When suspension with variable shock absorbers is installed, the car body is 10 millimeters (0.4 in) lower than with a normal suspension in the comfort setting and 23 millimeters (0.9 in) lower in the sport setting.
In the basic configuration, the driver can use this drive select system to regulate the behavior of accelerator pedal, automatic transmission, steering, cruise control or optional adaptive cruise control (ACC) and automatic air-conditioning in various modes, named Comfort, Auto, Dynamic and Efficiency. In connection with a navigation system, there is also the mode Individual, with which the driver can adjust each system as desired.