Audi A4

since 1994 of release

Repair and car operation

A4 Audi
- Running gear
   Protection of passengers
   Full zinc covering
   Full drive
   Drive concepts on all wheels
   Distributive torsen-differential
   Dynamics of movement on the dry road
   Maintenance instructions of quattro cars
   Mechanism of blocking of differential
   Additional works on maintenance
   Impellent compartment
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ exhaust System
+ cooling System
+ Fuel tank and fuel pump
+ Air filter and absorption channels
+ injection System
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
+ ignition System
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics

Running gear

On the design four levers of an independent suspension bracket correspond to the forward Audi A8 axis. At the expense of an arrangement of four cross-section levers that in management drive influence practically is not felt is reached.

In three drawings it is shown, where is – imagined – the left axis (arrow) at various turns of a wheel. The provision of an axis with operated wheels is especially important at the neutral provision of wheels. In this case it is almost precisely in the wheel center.

Audi A4 with a forward drive has the so-called back bridge with the interfaced levers. Generally it consists of two pipelike longitudinal levers which are connected by a krutilno-plastic V-shaped profile.

At Audi A4 quattro the so-called bridge with double cross-section levers in which center there is a drive on back wheels is behind established.

Peredny Bridge

At four levers of an independent suspension bracket of a forward axis in Audi each wheel copes four aluminum cross-section levers. Two top cross-section levers are fixed on a design by means of rezinometallichesky bearings and connected to a wheel support spherical heads with the lowered friction. Both bottom cross-section levers of a suspension bracket (on one – bearing and conducting levers) are fixed on a stretcher by means of the rezinometallichesky bearing, and each of them is connected to a wheel support a spherical head with the lowered friction. The gas-filled shock-absorber and a screw spring are connected in an amortization rack. The amortization rack does not assume a problem of management of wheels. The additional spring from cellular polyurethane in a combination to a coupling buffer spring in shock-absorbers provides comfortable interception of strong fluctuations of a body on a forward axis.

Levers of an independent suspension bracket are located in such a manner that substantially smooth out a pripodnimaniye of a forward part of the car in a start of motion and its lowering during braking. For decrease in longitudinal movements of an axis the internal bearing of the leading lever демпфируется a hydraulic way. The tubular stabilizer fixed on a stretcher which is connected to the bearing lever rod means, reduces a body list on turns.

At the expense of aluminum use in various details of an axis and in a constructive configuration, and also as a result of application of high-strength materials in springs it was possible to keep low weight of an expensive design of a suspension bracket. Positive properties of a forward suspension bracket with four levers of an independent suspension bracket form the block with operated wheels which passes almost vertically through the wheel center. With operated wheels the engineer means the alleged line round which the wheel moves at wheel movement by the block. The block with operated wheels near the middle of a wheel possesses big advantages as at a forward drive along with the efforts enclosed for turn of a wheel, also driving efforts which are applied again in the wheel center are transferred. The it is less than a distance between an axis with operated wheels and the center of a wheel, the lever and the less influence of hindrances on a steering is shorter than subjects.

At a forward axis with four levers of an independent suspension bracket in А4 influence of driving efforts on a steering as the distance between an axis with operated wheels and the wheel center is not enough is almost eliminated – it makes only 10 mm.

Zadny Bridge in cars with a forward drive

The known back bridge with the interfaced levers consists of two rigid on a bend and the krutilno-rigid pipelike longitudinal levers connected by krutilno-plastic, rigid on a bend by a V-shaped cross-section profile. The additional stabilizer is welded with the ends of longitudinal levers. Thanks to it high cross-section rigidity of the bridge and outstanding stability of a track are reached. This back bridge should be newly adjusted concerning many details. Thus the priority purpose is increase of comfortableness and stability of movement, decrease in noise and weight reduction.

The design of the back bridge with the interfaced levers promotes that at simultaneous compression of both wheels he behaves as the back bridge with longitudinal levers, and at serial compression of a spring amortization telescopic rack as the diagonal lever of an independent suspension bracket of the back bridge.

Zadny Bridge of the Quattro models

The Audi A4 quattro models are supplied with dual cross-section levers of an independent suspension bracket of wheels, including elastic support for back wheels. The top cross-section levers located over wheels, provide possibility of the device of a big luggage carrier.

The directing system of a suspension bracket of a wheel is provided with two triangular cross-section levers with the additional strezhnevy lever from each party. Shock-absorbers and screw springs are incorporated for economy of a place in amortization racks.

Brake system with ABS

The serial system of anti-blocking of the fifth generation with electronic distribution of brake effort of EBV provides high stability of braking in the most different traffic conditions and does unnecessary a mechanical regulator of brake effort. As electronic control of ABS possesses much more sensitive reaction, than a mechanical regulator of brake effort, essentially bigger range of adjustment is used. To provide stability of movement also when braking on turns, the share of brake effort on a back axis should be lowered. EBV distinguishes by means of sensors of frequency of rotation of ABS, whether Audi A4 rectilinearly moves or passes turn. On turn brake pressure upon back wheels decreases. Thanks to it back wheels can give the maximum effort of lateral withdrawal.

Electronic mechanism of blocking of differential of EDS

EDS is serially established on all quattro A4 models and enters into a special complete set of front-wheel models with four-cylinder engines with working volume from 1,8 l.

At electronic blocking of differential of EDS in all-wheel drive models it is a question of purposeful frictional coupling to three wheels, in front-wheel cars – one wheel. At the expense of it at a troganiye from a place in extreme conditions, for example at the slippery road, the maximum draft is provided.

Electronic adjustment of pro-slipping of wheels of ASR

In the front-wheel A4 models with V6 engines with working volume of 2,6 and 2,8 l as a special complete set for improvement of draft electronic adjustment of pro-slipping of wheels of ASR which possesses also all EDS functions is offered. If EDS includes purposeful frictional coupling for draft improvement, electronic adjustment of pro-slipping of wheels of ASR if necessary provides additional intervention in engine management. The sense of electronic adjustment of pro-slipping of wheels consists in avoiding a probuksovyvaniye of forward wheels irrespective of, how many gas the driver gives.