BMW 3 of the E46 series

since 1998 release

Repair and operation of the car

BMW 3 of the E46 series
+ BMW 3 Cars (E46)
+ Current leaving and service
+ Engine
+ Cooling systems, heating
- Power supply systems, injection and release
   Security measures and rules of observance of purity during the work with fuel system
   Removal and installation of the sensor of a reserve of fuel / fuel pump
   Check of the sensor of a reserve of fuel
   + Power supply system of petrol engines
   - System of injection of fuel of the petrol engine
      The general information and security measures at work
      Principle of work of DME system
      Removal and installation of injectors
      Check of system of injection of the petrol engine
      Check and adjustment of turns of idling and concentration WITH
   + Power supply system of diesel engines
   + System of production of the fulfilled gases
+ Electric equipment of the engine
+ RKPP and transmission line
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Schemes of electric equipment

Principle of work of DME system

Scheme of system of a digital control engine (DME)

1 — an adsorber
2 — the locking valve
3 — the valve of ventilation of a fuel tank
4 — the fuel pressure regulator
5 — an injector
6 — pressure zadatchik
7 — the ignition coil
8 — the situation sensor
9 — the pump of secondary air
10 — the locking valve
11 — the measuring instrument of mass of air
12 — a monitor
13 — the sensor of a butterfly valve

14 — an idling zadatchik
15 — the air temperature sensor
16 — the valve of recirculation of the fulfilled gases
17 — the fuel filter
18 — the detonation sensor
19 — the sensor of number of turns
20 — the engine temperature sensor
21 — the oxygen sensor
22 — the diagnostic socket
23 — a diagnostic lamp
24 — the differential sensor of pressure
25 — the fuel pump

Sensors of system of injection of petrol engines





Fuel is sucked in from a fuel tank by the electric gasoline pump located in a fuel tank and moves via the fuel filter to injectors. The regulator of pressure supports fuel pressure in system to constants.

Injectors have electric management and inject fuel pulsewise into the inlet pipeline in front of inlet valves of the engine.

Air is soaked up by the engine via the air filter and moves through knot of a butterfly valve, and also the inlet pipeline to inlet valves.

The injectable amount of fuel is defined, first of all, by the mass of the soaked-up air. The mass of the soaked-up air is defined by the measuring instrument located in the inlet pipeline. In the case of the measuring instrument of weight there is a thin, electrically warmed plate which is cooled with the passing air stream. The control system changes value of current of heating so that temperature of a plate remained a constant. If, for example, the amount of the soaked-up air increases, the plate seeks to be cooled. Thereof value of current of heating of a plate grows. The control system of the engine determines the mass of air by heating current deviations and respectively regulates amount of injectable fuel.

Information arriving from various sensors, and the teams arriving to executive bodies ensure optimum functioning of the engine in any mode. If sensors fail, the monitor switches in emergency operation to exclude damages of the engine and to provide possibility of the further movement of the car. Failure of sensors not necessarily has to be felt on deterioration of operation of the engine. However no later than the next review period of the fulfilled gases data on it will be brought in memory of malfunctions of a control system of the engine.

- Zadatchik of idling operates amount of air idling bypassing a butterfly valve. It provides maintenance of constant number of turns idling irrespective of connection of additional consumers as, for example, the power steering or the compressor of cooling.

- Sensors of temperature of cooling liquid and the sensor of temperature of the soaked-up air report the current value of temperature as a result of change of resistance of the resistor. At increase of temperature resistance decreases.

- The system of ventilation of a fuel tank consists of an adsorber and the locking valve. In an adsorber fuel couples which are formed as a result of fuel heating accumulate. During the operation of the engine of couple otsysyvatsya from an adsorber and move in engine combustion chambers.

- Sensors of oxygen measure the content of oxygen in the fulfilled gases before and after the catalytic converter and transmit the corresponding signals to the control unit of the engine.

- The relay of the fuel pump is in the relay block over a ware box. The relay gives current to the fuel pump.

- The system of ignition has no mobile parts, the traditional distributor of ignition is absent. Each spark plug has the coil.

- The ignition tension monitoring system at too low voltage switches-off the DME block (for example, owing to damage of a cable). Thus the engine cannot be started. It excludes damages of the catalytic converter.

- The system of anti-detonation regulation serves for definition and regulation of optimum time of ignition for each cylinder. If there is a malfunction in system of ignition, supply of fuel to the corresponding cylinder stops.

- 320i, 323i, 328i: The system of regulation of phases of gas distribution (the moments of opening and closing of inlet and final valves) which is shortly called by Doppel VANOS turns both camshafts in relation to asterisks on the corner providing optimum phases of gas distribution on any power setting and consequently optimum idling, high characteristics of a torque and lowered fuel consumption. Turn is carried out under pressure of oil. For this purpose the DME system via the electrooperated valve regulates oil pressure in the operating VANOS element.

- The adjustable inlet pipeline depending on number of turns of the engine regulates length of the inlet pipeline. For this purpose the rotary gate with pneumomanagement is installed in the inlet pipeline. Big length of the pipeline at low number of turns thanks to a resonance provides good filling of cylinders and by that higher torque. At a large number of turns length of the soaking-up path decreases that increases engine capacity potential.