Audi A3

since 1997 of release

Repair and car operation



Audi A3
+ Maintenance instruction
+ Current leaving and service
+ Engine
+ Systems of cooling, heating
- Power supply system and production of the fulfilled gases
   + Power supply system
   + System of injection of fuel
   - System of injection of the diesel engine
      Direct injection
      Removal and installation of nozzles
      Check and adjustment of the beginning of injection of TNVD
   + System of production of the fulfilled gases
+ engine Electric equipment
+ Manual box of gear shifting
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Elektroskhema









38a8de3e


Direct injection

GENERAL INFORMATION

Arrangement of elements of fuel system in a TDI engine compartment

1-the valve of system of a retsirkulyatsiya of the fulfilled gases
2-Perepuskny the valve of a soaking-up zaslonka
3-a nozzle with the sensor of moving of a needle
4-monitor
For system of direct injection of fuel.
The sensor of height is built in a monitor.
5-Ø/m the valve of vacuum management of a retsirkulyatsiya of the fulfilled gases
6-electromagnetic valve
For restriction of pressure of submitted air.
7-measuring instrument of weight of air
8-the sensor of temperature of cooling liquid
9-sensor of turns of the engine
10-shtekerny connection
Sensor of moving of a needle.
11-shtekerny connection of the sensor of number of turns of the engine
12-shtekerny connection of TNVD
For the sensor of temperature of cooling liquid, a zadatchik of quantity, the sensor of moving of an adjusting zaslonka, the valve of switching off of supply of fuel and the valve of the beginning of injection.
13-the valve of the beginning of injection of fuel, д / in pressure of oil
14-valve of shutdown of supply of fuel
15-executive body of regulation of amount of injected TNVD fuel
With the sensor of temperature of fuel, a quantity zadatchik sensor of moving of an adjusting zaslonka.
16-the sensor of pressure of soaked-up air with the sensor of temperature of soaked-up air.
Other details (are not represented).
17-control unit transmission
18-heating element of PSV system
19-sensor of temperature of fuel, quality regulator, sensor of replacement of modulation of the piston
And - the switch of a pedal of a brake
In - the region of feet, at a brake pedal.
In - the stoplight switch
In - the region of feet, at a brake pedal.
With - the sensor of provision of a pedal of gas
In - the region of feet, at a brake pedal.
D-switch of a pedal of coupling
In - the region of feet, at a coupling pedal.

Vacuum pipelines of the turbodiesel engine (TDI)

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

ATTENTION

On an illustration ALH and AHF engines are shown. AGR engines have no vacuum system of regulation of pressure of submitted air. Explanations to work of system of a retsirkulyatsiya of the fulfilled gases are provided in subsection Operation of the catalytic converter.


Fuel pump of a high pressure

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

Here TNVD directly injects fuel into the combustion chamber, namely, in a cavity in the piston. At this TNVD creates pressure the 900th bar and injects fuel into two steps.

Thanks to mnogosopelny nozzles and the two-spring holder of a nozzle preliminary injection of a small amount of fuel which, burning down at first is made, creates favorable conditions for injection of the main amount of fuel. Such process of injection provides the soft and silent combustion similar to vikhrekamerny combustion. The amount of injected fuel is regulated by an electronic monitor. Advantage of such injection consists in decrease almost for 20 % of fuel consumption. As operating parameters of process of injection signals of various sensors are used. Them treat:

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

For quality achievement of combustion of fuel the soaking-up channel is executed so that air on a way to the chamber of combustion 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 below – 10°С.

Before getting to TNVD 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 plan.

TNVD does not demand service. Details of the pump are greased with diesel fuel. The pump is given in rotation by cranked shaft through a gear belt.

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