Audi A4

since 1994 release

Repair and operation of the car



A4 Audi
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ 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
      The major knots
      So the system of injection of Motronic functions
      Violations in work and self-diagnostics
      The self-help at injection
      Visual control
      Search of malfunctions in separate knots
      Check of idling and exhaust gases
      Check of exhaust gases (AU)
      Cable of a butterfly valve
      The help at malfunctions
   + System of injection of MPI and MPFI
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
+ System of ignition
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics





So the system of injection of Motronic functions

Start of the cold engine: in addition to the soaked-up air the control unit of a butterfly valve lets in additional amount of air. At the same time the control unit receives from the sensor of temperature of cooling liquid information – "the engine cold". On the basis of it the control unit counts duration of opening of valves of injection for receiving the enriched mix.

Warming up of the engine: the sensor of temperature of cooling liquid transfers to the control unit of data on the increasing heating of cooling liquid. The control unit gives team of closing of the valve of stabilization of idling, and duration of injection comes back to standard level.

Idling: on the basis of information received from a potentiometer of a butterfly valve and the measuring instrument of a stream of fresh air, the control unit learns when the engine idles. If the number of turns falls, the control unit changes the ignition moment; at the same time the control unit of a butterfly valve increases an air stream therefore the amount of injectable fuel slightly increases.

Standard operation does not demand any special equipment. The provision of a butterfly valve and amount of the air passing through its measuring instrument determine duration of opening of valves of injection.

Accelerations: fast opening of a butterfly valve is distinguished by the control unit as acceleration on the signal which arrived from a potentiometer of a butterfly valve.

Adjustment by means of a lambda probe: continuous change of slightly enriched and a little grown poor fuel and air mix is necessary for excellent job of the catalytic converter. At the moment the lambda probe (in the catalytic converter) transfers information on the content of residual oxygen in an exhaust to the control unit which gives the order to fractions of a second to injectors to extend or reduce time of injection and, therefore, intake of gasoline.

Draft shutdown: information that the foot is removed from a gas pedal, through a potentiometer of a butterfly valve in the block of its management again comes to the control unit. If at the same time the sensor of temperature of cooling liquid signals about achievement of an eksplutatsionny warming up of the engine, and the Hall sensor in the distributor directs information that the frequency of rotation of the engine exceeded 1500 rpm, the control unit does not give the order to injectors any more to open.

Full loading: at full loading in the conditions of completely wrung out gas pedal the engine needs the increased amount of fuel. On the basis of the signal "full gas" which arrived from a potentiometer of a butterfly valve in combination with the corresponding signal of the measuring instrument of a stream of fresh air, the control unit distinguishes a condition of "full gas" and forces injectors to make injection more long.

Restriction of number of turns: the control unit disconnects injectors for protection of the engine against excess of frequency of rotation if it exceeds 6500 rpm (the engine with a working volume of 1,6 l) or 6800 rpm (the engine with a working volume of 1,8 l).

Function of the emergency course: if from one of sensors of information senseless information does not arrive or arrives, Motronic does not fail yet. The control unit chooses the so-called auxiliary size which is in a database.