Audi 80/Avant (B4)

Since 1991-1995 of release

Repair and car operation

Audi 80/Avant
+ The description
+ Engines
+ System of release of the fulfilled gases
+ Cooling system
+ Fuel tank and the fuel pump
+ The air filter and воздухозаборные channels
- Injection system
   + System of injection Mono-Motronic
   + System of injection Digifant
   + System of injection KE-III-Jetronic
   + Systems of injection MPI and MPFI
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Antiblocking system of brakes
+ Wheels and tyres
+ Kuzovnaja electrosystem
+ Ignition system
+ Illumination
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ Body elements
+ Search of malfunctions
+ Specifications


Injection system

System of injection Mono-Motronic

Function chart of system of injection Mono-Motronic


In drawing the atomizer (2) with even connected tip (1), (3) blocks of preparation of a gas mixture taken from a nest is shown впрыскная. Sideways on the valve the fuel strainer is visible.

The disassembled regulator of pressure:

1 – a cover;
2 – a spring;
3 – a membrane;
4 – a basic surface.

The regulator of position throttle заслонки (1) can be removed separately. It is necessary, if is faulty приводной a pusher of the switch of a signal of idling (2). The position (3) designates a persistent bolt throttle заслонки.

The potentiometer throttle заслонки is established and regulated at factory and it cannot be assorted. We only have removed it to show you sliding contacts and spending paths. In case of malfunction it is necessary to replace the block of preparation of a gas mixture.

The central injection

The smallest engine Audi is equipped by system of injection of gasoline through one atomizer and throttle заслонку, so-called system Mono-Motronic. It consists basically of the case similar to the case of the carburettor and supplied one and only впрыскной with the atomizer. The exit of fuel from an atomizer is regulated by the electronic block of management which simultaneously provides management of regulation of an advancing of ignition. In more details about system Mono-Motronic you learn in the head ignition System.

Basic elements

The management block

It is located in the field of feet of the forward passenger in front of the heating channel and through the multicontact tip receives the information from following knots:

    The Hall gauge in the ignition distributor – about frequency of rotation of the engine. Ljambda-probe in каталитическом neutralizer – about the maintenance of residual oxygen in the fulfilled gases. Potentiometer – about position throttle заслонки and by that quantity of arriving air. The gauge of temperature of arriving air on an input of the block of preparation of a gas mixture – about temperature of arriving air. The temperature gauge on a branch pipe of a cooling liquid at the left on a head of the block of cylinders – about temperature of a cooling liquid.

Processing entering signals the management block counts duration of opening впрыскной atomizers with an electromagnetic drive and by that quantity of injected fuel. Thus the management block uses многопараметровые engine characteristics – a file in which all possible conditions of the engine are written down. In the same place in the form of electric signals data concerning this or that situation on quantities of fuel are written down. In addition in the form of characteristics in Mono-Motronic indicators of the moments the ignitions concerning quantity of fuel and an operational situation are kept.

Throttle заслонка

It is located at the very bottom of the block of preparation of a gas mixture and regulates quantity of air which the engine should receive.

Opening degree заслонки is defined by the driver by pressing an accelerator pedal. A pedal and throttle заслонка are directly connected with each other by means of тросового an accelerator drive.

The block of preparation of a gas mixture

The majority of details of the central system of injection of gasoline are collected in this case. Through it passes arriving air, here again – by means of an atomizer – fuel, as well as in the carburettor is added.

Vprysknaja atomizer

It opens by means of an electromagnet. Thus fuel can arrive – or not – depending on a signal from the management block. For optimum dispersion of fuel the atomizer is supplied by oblique final apertures through which gasoline gets on a conic wall of a final aperture, завихряясь there.

The vprysknaja atomizer can open and be closed only, but not in a condition doses out quantity of fuel. Therefore its regulation occurs on injection time. It is carried out as follows: the atomizer injects once at each impulse of a power-current from the Hall gauge. If the fuel small amount the atomizer opens at this impulse only for short time – often more shortly, than on one thousand is required seconds. If it is necessary for the engine of more fuel (at cold start or full loading), injection occurs during more long time. And so at each impulse of the gauge of the Hall.

The gauge of temperature of arriving air

It is located sideways on the case of an atomizer and thus can is exact define temperature of air arriving in the block of preparation of a gas mixture.

Pressure regulator

The fuel pump under pressure submits gasoline to a regulator of pressure which provides gasoline receipt to an atomizer under the same pressure 0,8 – 1,2 bar. For this purpose he allows большей or smaller part of gasoline to leave back in a fuel tank on a drain highway. Giving through the fuel filter remains almost constant.

Regulator of position throttle заслонки

The small electric motor with angular transfer moves приводной a pusher more close or further from an emphasis of idling throttle заслонки. Thus, depending on a situation throttle заслонка can open on the big or smaller size.

Thanks to it frequency of rotation of idling remains to a constant at various loadings. Ahead in приводном a pusher of a regulator of position throttle заслонки the so-called switch of a signal of idling which informs the management block if you release an accelerator pedal is located. This signal is necessary for stabilisation of frequency of rotation of idling.

Potentiometer throttle заслонки

He informs the management block on movements throttle заслонки and its position. So, for example, fast opening throttle заслонки is distinguished as car acceleration. If you clean a foot from an accelerator pedal the signal of closing throttle заслонки activates a fuel stopping delivery in an idling mode. The message passes in a kind of an electric signal – the potentiometer represents not that other as variable resistance.