Audi A4, S4
Since 2000 of release
Repair and car operation
Audi A4, S4
+ Controls and receptions of safe operation
+ Current leaving and service
+ The engine
+ Systems of cooling, heating and the air conditioner
- Power supply systems, release and decrease in toxicity of the fulfilled gases
+ Power supply systems of petrol and diesel engines
- System of injection of fuel of the petrol engine
The general data and security measures
Functioning of a control system and injection of the petrol engine
The general check of system of injection of the petrol engine
Check and adjustment of number of turns of a single course/moment of ignition/concentration WITH
+ System of injection of fuel of the diesel engine
+ Systems of release and decrease in toxicity of the fulfilled gases. turbocharger
+ Systems of an electric equipment of the engine
+ Manual box of a gear change
+ Automatic transmission
+ Coupling, power shafts and differential
+ Brake system
+ Suspension bracket and steering
+ Onboard electric equipment
Functioning of a control system and injection of the petrol engine
Elements of control system Motronic in a compartment of engines of 1.8 l (AVJ, BFB)
Fuel distributive highway and injectors. The engine of 1.8 l AVJ/BFB
Control system elements in a compartment of engines V6
Control system elements in a compartment of engines of model S4
Fuel is sucked in from a fuel tank by the electric fuel pump and moves through the fuel filter to a fuel distributive highway. The pressure regulator provides pressure maintenance in the fuel system, equal 3.5, 4.0 or 6.0 атм., depending on the engine.
Through electrooperated injectors fuel импульсно is injected into the inlet pipeline located directly ahead of inlet valves of the engine. The engine management block makes consecutive management of injectors according to ignition order, regulates time of injection and, thereby, quantity of injected fuel.
Air necessary for formation of a fuel mix, is sucked in by the engine through the air filter and arrives through throttle заслонку and the inlet pipeline to inlet valves. The quantity of soaked up air is regulated throttle заслонкой which moves the step-by-step electric motor operated the block of management of the engine. At турбированных engines soaked up air is compressed турбокомпрессором, set in motion by exhaust gases of system of release. Then compressed air is cooled in a cooler of forced air and arrives in the engine for formation of a fuel mix.
The volume of soaked up air is defined by a measuring instrument of quantity of air. The measuring instrument is located in the channel of soaked up air. In the measuring instrument case the warmed touch plate cooled by the passing stream of soaked up air is located thin, электрически. The electric current which is heating up a plate, is regulated by a control system so that to maintain temperature of a constant plate. If, for example, the quantity of soaked up air increases, the temperature of a heated up plate starts to decrease. Thus the electric current size increases at once to keep temperature of a plate invariable. Fluctuations of an electric current of a plate specify to the engine management block in its condition of loading that allows to define quantity of injected fuel correctly.
The management block defines optimum time of ignition, the moment of injection and quantity of injected fuel. Thus there is a coordination of work of the block of management with other systems of the car, for example, to management of a transmission or anticreeping system.
The information from other gauges and the operating pressure arriving to executive powers, provide optimum work of the engine in any situation. If some gauges fail, the management block is switched in a mode of the emergency program to exclude possible damage of the engine and to provide the further movement of the car. In this case the engine works non-uniformly and at gas increase has propensity to a stop.
Gauges and executive mechanisms of system of injection
The gauge of position of a cranked shaft will screw in the block of cylinders at a flywheel. It hands over to the block of management the information on number of turns of the engine and position ВМТ of the piston of the first cylinder.
The gauge of position of a camshaft is located in an end face of a cover of a head of cylinders. It together with the gauge of position of a cranked shaft hands over to the block of management the information about ВМТ the piston of the first cylinder. It serves for synchronisation of the moment of ignition and sequence of ignition.
The potentiometer throttle заслонки is located in the executive mechanism throttle заслонки and gives the block of management the information on current coal of position throttle заслонки. The second potentiometer gives the block of management the information on base value and forms a spare signal at failure of a potentiometer throttle заслонки.
The gauge of a pedal of an accelerator is located area of an arrangement of feet of the driver directly on a pedal axis. It gives the block of management the information on pedal position. From reasons of reliability from the pedal gauge the duplicating signal, just as from a potentiometer throttle заслонки arrives.
Gauges of temperature of a cooling liquid it is located in the thermostat case. It represents the resistor with the negative temperature factor which resistance decreases with temperature growth.
The gauge of temperature of soaked up air also represents the NTC-resistor.
The system of ventilation of a fuel tank consists of an adsorber and the electromagnetic valve. In an adsorber the fuel steams formed as a result of heating of fuel accumulate. At work of the engine of pair are sucked away from an adsorber and move in chambers of combustion of the engine.
Ljambda-probes (oxygen gauges) measure the oxygen maintenance in the fulfilled gases before and after каталитического the converter and transmit corresponding signals in the engine management block. One ljambda-probe is located before, and another after каталитического the converter.
The detonation gauge will screw sideways in the block of cylinders. It interferes with occurrence of dangerous shock combustion of a fuel mix. Thanks to it the ignition moment can keep on detonation border that provides an effective utilisation of energy of combustion of fuel and by that reduces the fuel expense.
The switched inlet pipeline (the engine of 2.0 l ALT)
The necessary characteristic of capacity and twisting moment is reached by means of the two-level switched inlet pipeline. Thus switching of the pipeline with short on the long occurs in a range of turns 2.000 – 3.700 in minute the Switching platen dividing by means of elastic sealing rings and sealing laths separate inlet channels, opens soaking up path. Switching between twisting moment and capacity positions occurs электропневматически (depending on loading, number of turns and temperature) (address to illustrations more low).
The accelerator servo-driver
Instead of a usual drive of gas on a gas pedal there is a gauge of position of a pedal (an illustration more low) which hands over to the block of engine management the information on pedal position. On the basis of the received information the management block through the electric motor operates position throttle заслонки.
In the case of the gauge of position there are two contact potentiometers which are fixed on the general to a shaft. At each change of position of a pedal resistance of potentiometers and the pressure transferred to the block of engine management changes.
At failure of any gauge the lamp of malfunction of a drive of gas lights up and in memory of malfunctions of the block of management damage is registered. If out of operation there are both gauges the engine works with the raised number of turns and does not react any more to a gas pedal.
The block of a drive throttle заслонки (address to an illustration more low) includes in the structure the electric motor, two potentiometers and system of cogwheels with a returnable spring. It regulates position throttle заслонки. A problem of the block of management is stabilisation of turns of idling, irrespective of connection of additional consumers, as for example, the hydraulic booster of a wheel or the conditioner compressor.
The potentiometer throttle заслонки is at a shaft throttle заслонки and hands over to the management block the current information on position coal заслонки. The second potentiometer hands over to the block of management the information on basic value and provides a spare signal at potentiometer failure.