Audi A3

Since 1997 of release

Repair and car operation



Audi A3
+ The maintenance instruction
+ Current leaving and service
+ The engine
+ Systems of cooling, heating
- The power supply system and release of the fulfilled gases
   + The power supply system
   + System of injection of fuel
   - System of injection of the diesel engine
      Direct injection
      Removal and installation of atomizers
      Check and adjustment of the beginning of injection ТНВД
   + System of release of the fulfilled gases
+ Engine electric equipment
+ Manual box of a gear change
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Electroschemes





Direct injection

THE GENERAL DATA

Arrangement of elements of fuel system in engine TDI compartment

1 - the system valve recycling the fulfilled gases
2 - перепускной the valve soaking up заслонки
3 - an atomizer with the gauge of moving of a needle
4 - a monitor
For system of direct injection of fuel.
The height gauge is built in a monitor.
5 - Э/м the valve of vacuum management рециркуляцией the fulfilled gases
6 - the electromagnetic valve
For restriction of pressure of submitted air.
7 - a measuring instrument of weight of air
8 - the gauge of temperature of a cooling liquid
9 - the gauge of turns of the engine
10 - штекерное connection
The gauge of moving of a needle.
11 штекерное connection of the gauge of number of turns of the engine
12 - штекерное connection ТНВД
For the gauge of temperature of a cooling liquid, задатчика quantities, the gauge of moving adjusting заслонки, the valve of deenergizing of giving of fuel and the valve of the beginning of injection.
13 - the valve of the beginning of injection of fuel, д/в pressure of oil
14 - the valve of switching-off of giving of fuel
15 - an executive office of regulation of quantity of injected fuel ТНВД
With the gauge of temperature of fuel, задатчиком quantities the gauge of moving adjusting заслонки.
16 - the gauge of pressure of soaked up air with the gauge of temperature of soaked up air.
Other details (are not represented).
17 - the block of management of transmission
18 - a heating element of system PSV
19 - the gauge of temperature of fuel, a quality regulator, the gauge of replacement of modulation of the piston
And - the switch of a pedal of a brake
In - area of feet, at a brake pedal.
In - the stoplight switch
In - area of feet, at a brake pedal.
With - the gauge of position of a pedal of gas
In - area of feet, at a brake pedal.
D - the switch of a pedal of coupling
In - area of feet, at a coupling pedal.

Vacuum pipelines of the turbodiesel engine (TDI)

1 - the system valve recycling the fulfilled gases
2 - to a vacuum box of regulation of pressure of submitted air
At турбокомпрессора.
3 - to a vacuum box for заслонки the inlet pipeline
4 - the valve of switching for заслонки the inlet pipeline
Заслонка the inlet pipeline reduces jerks at an engine stop. At engine AGR it is established not always.
5 - the pipeline from a tee–7
6 - the valve of adjustment of system recycling the fulfilled gases
7 - a tee
8 - the electromagnetic valve of restriction of pressure of submitted air
9 - the return valve
10 - from the brake amplifier
11 - the air filter
12 - the return valve
13 - the vacuum pump
14 - the vacuum tank

ATTENTION

On an illustration engines ALH and AHF are shown. Engines AGR do not have vacuum system of regulation of pressure of submitted air. Explanatories recycling the fulfilled gases are resulted in system work in subsection Work каталитического the converter.


The fuel pump of a high pressure

1 - a bolt, the inhaling moment:
20 - Н m + ј a turn (90 )
Necessarily replace.
2 - cogwheel ТНВД
3 - a nut
To turn on it is not supposed.
4 - the connecting union, 25 Н m
For the submitting pipeline, from the fuel filter.
5 - ТНВД
6 - the valve of a stopping delivery of fuel, 40 Н m
7 connecting union
For the returnable pipeline.
8 - the returnable pipeline
To the fuel filter.
9 - a nut, 25 Н m
10 - high pressure pipelines, 25 Н m
11 - the connecting union, 45 Н m
12 - a bolt, 25 Н m
13 - an atomizer
The atomizer of the third cylinder has the gauge of moving of a needle.
14 - a bolt, 20 Н m
15 - a collar
16 - a support
17 - heat-shielding consolidation
Necessarily replace.
18 - a bolt, 10 Н m
19 - the valve of the beginning of injection of fuel
20 - a grid
21 - a sealing ring
Necessarily replace.
22 - a bolt, 25 Н m
23 - a cover of a regulator of injection
24 - the plug with a nut
25 - the console
26 - a bolt, 25 Н m

Here ТНВД directly injects fuel into the combustion chamber, namely, in a cavity in the piston. Thus ТНВД creates pressure 900 bar and injects fuel in two steps.

Thanking многосопельным to atomizers and to the two-spring holder of an atomizer preliminary injection of a small amount of fuel which, burning down at first is made, creates favorable conditions for injection of the basic quantity of fuel. Such process of injection provides the soft and silent combustion similar вихрекамерному to combustion. The quantity of injected fuel is regulated by an electronic monitor. Advantage of such injection consists in decrease almost on 20 % of the expense of fuel. As operating parametres of process of injection signals of various gauges are used. Them concern:

– The gauge of a pedal giving to a monitor the information on position of a pedal of gas. The gas drive to ТНВД is absent.
– The gauge of number of turns.
– The gauge of moving of a needle at an atomizer. Thanks to this gauge the beginning of injection is defined and process of injection depending on loading and number of turns of the engine is regulated.
– The gauge of pressure of submitted air.
– The gauge of temperature of submitted air.
– The gauge of temperature of a cooling liquid.
– The gauge of temperature of fuel.
– A potentiometer of moving regulating заслонки. Signals are used by a monitor as a feedback for exact positioning regulating заслонки in ТНВД which is an indicator of the valid quantity of injected fuel.

For quality achievement of combustion of fuel the soaking up channel is executed so that air on a way to the combustion chamber received a vortical trajectory. Owing to higher starting properties in a cold condition of the engine with direct injection preliminary heat is required only at temperature more low-10S.

Before getting in ТНВД fuel passes through the fuel filter. In the filter fuel separates from water and pollution. Therefore it is important to delete water from fuel and to make timely replacement of a filtering element according to the maintenance service plan.

ТНВД does not demand service. Pump details are greased with diesel fuel. The pump is resulted in rotation by cranked shaft through a gear belt.

The prevention: At work with fuel system of the diesel engine it is necessary to observe a security measure and cleanliness.
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