Audi A4

since 1994 release

Repair and operation of the car

Peredny Bridge

At four levers of an independent suspension bracket of a forward axis in Audi each wheel copes four aluminum cross levers. Two top cross levers are fixed on a design by means of rubber-metal bearings and connected to a wheel support spherical heads with the lowered friction. Both lower cross levers of a suspension bracket (on one – the bearing and conducting levers) are fixed on a stretcher by means of the rubber-metal 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 a depreciation rack. The depreciation 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 way that substantially smooth out a pripodnimaniye of 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 is damped in the hydraulic way. The tubular stabilizer fixed on a stretcher which is connected to the bearing lever by means of a rod, reduces a body list on turns.

Due to use of aluminum in various details of an axis and in a constructive configuration, and also as a result of use of high-strength materials in springs it was possible to keep the 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 the operated wheels which passes almost vertically through the center of a wheel. With the operated wheels the engineer means the alleged line round which the wheel at the movement of a wheel moves by the block. The block with the operated wheels near the middle of a wheel has big advantages as at the forward drive along with the efforts used for turn of a wheel also driving efforts which are made in the center of a wheel again are transferred. The it is less than a distance between an axis with the operated wheels and the center of a wheel, the lever and the less influence of hindrances on a steering is shorter.

At a forward axis with four levers of an independent suspension bracket in A4 influence of driving efforts to a steering as the distance between an axis with the operated wheels and the center of a wheel is not enough is almost eliminated – it makes only 10 mm.

Zadny Bridge in cars with the forward drive

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

The design of the back bridge with the interfaced levers promotes that at simultaneous compression of both wheels it behaves as the back bridge with longitudinal levers, and at serial compression of a spring depreciation 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 levers of an independent suspension bracket of wheels, including elastic support for back wheels. The top cross 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 levers with the additional strezhnevy lever from each party. Shock-absorbers and screw springs are united for economy of a place in depreciation 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 the mechanical regulator of brake effort. As electronic control of ABS possesses much more sensitive reaction, than the mechanical regulator of brake effort, the bigger range of adjustment is used significantly. To provide stability of the movement also when braking on turns, the share of brake effort on a back axis has to be lowered. EBV distinguishes by means of sensors of frequency of rotation of ABS, whether Audi A4 rectilinearly moves or passes turn. On turn the 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 serially is established on all quattro A4 models and enters a special complete set of front-wheel models with four-cylinder engines with a working volume from 1,8 l.

At electronic blocking of differential of EDS in all-wheel drive models it is about purposeful frictional coupling to three wheels, in front-wheel cars – one wheel. At the expense of it at start-off 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 a 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.