since 1994 release
Repair and operation of the car
+ Running gear
+ Regular servicing
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
- System of injection
+ System of injection of Motronic
- System of injection of MPI and MPFI
Knots of system of injection
Adjustment with the help a lambda probe
Violations in work and self-diagnostics
Check of knots
Dismantle of separate details
Cable of a butterfly valve
Check of exhaust gases
The help at malfunctions
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Wheels and tires
+ Electrotechnical equipment
+ System of ignition
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
Search of malfunctions
Knots of system of injection
In order that it is better to understand functioning of system of injection in general, in the beginning it is important to learn about problems of its separate knots.
1 — the Sensor of number of turns of the engine
This scheme illustrates the electric party of system of ignition/injection, in this case on the example of MPFI with the air pressure sensor in an inlet collector. On the left side sensors and sensors which influence behavior of the control unit are placed. On the right those knots of ignition and injection to which the control unit sends the signals are represented.
Fuel party of system of ignition/injection of MPI/MPFI
At the left: valves of injection (1, 2 and 3) in the six-cylinder engine are located groups on three on the right and to the left of the central inlet collector.
Between the entering information (from various sensors) and valves of injection there is an electronic control unit. Depending on the existing conditions of loading and temperature it sends absolutely certain amount of fuel to the engine. For this purpose the control unit varies duration of opening of the injection valves operated in the electromagnetic way. The amount of injectable fuel can change only at the expense of injection duration. Information for determination of duration of injection comes to the control unit from various knots, it:
In the channel of absorption of each cylinder of the engine takes place on one valve of injection. It gives amount of fuel necessary at present to each cylinder and at the same time provides thin dispersion of gasoline.
Distributive tube of fuel
It serves for uniform supply of fuel to all valves of injection. Besides, the distributive tube functions as the collector and thanks to it does not allow fluctuations of pressure. The ring-shaped form of a tube allowing to give fuel to all six valves is interesting.
Fuel pressure regulator
It settles down behind on the right on a distributive tube of fuel and has to keep the constant pressure of fuel in a distributive tube. It provides it by increase or reduction of amount of the fuel flowing on a recirculation tube. If more fuel comes back, pressure goes down; at small return of fuel it rises.
Fuel pump and relay
In more detail you learn about the fuel pump with the electric drive, the relay of the fuel pump and other MPI/MPFI relays in the head the Fuel tank and the fuel pump.
Measuring instrument of pressure of fresh air
In a stream of the soaked-up air the wire which heats up in the electric way is placed. Depending on the mass of the soaked-up air the stream of air which cools a wire stronger or more weakly changes. Change of temperature causes change of resistance of a wire, and it is measured by the control unit.
The air pressure sensor in an inlet collector
The air pressure sensor in an inlet collector is in the MPFI control unit. The inlet collector and the sensor unite among themselves a thin hose. For the control unit air pressure in an inlet collector is the major information for calculation of load of the engine. It has impact on duration of injection and at the time of ignition.
Sensor of temperature of a stream of fresh air
The sensor of temperature of the soaked-up air is screwed in to the canal of absorption of the third cylinder (behind on the right). In addition to the air pressure sensor it serves the control unit for calculation of load of the engine. At high temperature of the soaked-up air (it is equivalent the low density of air) injection time, for example, has to be reduced and the moment of ignition is slightly more shifted in the direction "later".
Branch pipe of a butterfly valve
Where the stream of fresh air enters an inlet collector of the engine, in the union there are two butterfly valves. Smaller from them it is connected by a cable of a butterfly valve to a pedal in salon. It doses a stream of the soaked-up air in the engine to the provision of semi-gas.
Potentiometer of a butterfly valve
The potentiometer of a butterfly valve is put in action by its shaft. The potentiometer defines the provision of a butterfly valve at present and in the form of voltage sends a signal to the control unit. This information on loading, besides other signals, is used by the control unit for adjustment of idling, a choice of the characteristic of ignition and calculation of duration of injection.
Idling stabilization valve
As it is clear according to the name, this valve provides constant number of turns of idling – not important, the engine is heated-up or not, consumers of power (climatic installation) are connected or not.