Daewoo Nexia

Since 1994 of release

Repair and car operation

Daewoo Nexia
+ The maintenance instruction
+ Maintenance service
+ The engine
+ 3. The engine (two top camshafts)
+ Cooling system
- Fuel and exhaust systems
   5.2. System of injection of fuel
   5.3. Modes of functioning of system
   + 5.4. The basic knots of system
+ Electric chain
+ 7. Ignition system
+ 8. The electronic block of management and gauges
+ Transmission
+ 10. A five-speed transmission and the main transfer RPO MM5
+ 11. Automatic Transmission
+ Steering
+ Running gear
+ 14. A forward suspension bracket
+ 15. A drive of forward wheels
+ 16. A back suspension bracket
+ Brake system
+ Body
+ Heating, ventilation
+ Electric equipment

5.3. Modes of functioning of system

ECU carries out dispensing of the fuel arriving in the Engine, on the basis of processing of signals of several gauges. ECU supports some operating modes МСВТ which are described more low.

Mode of start-up of the engine

At inclusion of ignition ECU starts on two seconds the fuel pump which lifts pressure in fuel system. Simultaneously ECU processes signals of gauges of temperature of a cooling liquid (ДТЖ) and positions throttle заслонки (ДДЗ) and counts demanded for start-up of the engine structure топливовоздушной mixes. The structure топливовоздушной mixes depends on temperature of a cooling liquid and can change oт 1:1,5 at–36 C дo 1:14,7 at 94 C. ECU regulates quantity of the fuel arriving in the inlet pipeline, at the expense of change of duration of phases of opening and closing of valves of atomizers. For management of electromagnetic valves of atomizers the electric signal of an alternating voltage is used.

Mode of a purge of cylinders

At strong enrichment топливовоздушной a mix and difficulty of start of engine EBU provides possibility of a purge of cylinders for removal of superfluous fuel and drying of spark plugs. At full opening throttle заслонка and frequency of rotation of a cranked shaft of the engine approximately to 400 rpm ECU stops fuel giving. If a little to cover throttle заслонку (opening degree заслонки should not exceed approximately 80 %), ECU will return МСВТ in a mode of start-up of the engine.

Operating conditions

The operating conditions have two versions. ECU (OS) can operate МСВТ in a mode with the closed or opened feedback.


At engine start-up when frequency of a cranked shaft exceeds 400 rpm system starts to work in a mode from opened OS. In this mode ECU carries out fuel dispensing only on the basis of processing of signals ДТЖ and ДАД. Signal ДКК is not considered. ECU supports an operating mode from opened OS until following conditions will be satisfied.

1) Pressure of signal ДКК starts to change that testifies about пригреве the gauge to working temperature.

2) Signal ДТЖ corresponds to threshold value of temperature.

3) Has passed the set time interval after engine start-up.


Concrete values of the parametres listed above, depend on model of the engine and are written down in SPPZU ECU. At performance of all conditions ECU passes to management МСВТ in a mode from closed OS. In this mode fuel dispensing defined by duration of opening of valves of atomizers, is carried out on the basis of processing of signals ДКК in the fulfilled gases that allows ECU to support structure топливовоздушной mixes near optimal to value 1:14,7.

Acceleration mode

ECU reacts to fast increase in a corner of opening throttle заслонки and speeds of an air stream in the inlet pipeline increase in giving of fuel.

Delay mode

ECU reacts to reduction of a corner of opening throttle заслонки and speeds of an air stream in the inlet pipeline reduction of giving of fuel. At very fast отпускании pedals of accelerator ECU can stop completely for some time fuel giving in the Engine.

Mode of indemnification of the category of the storage battery

At a voltage reduction of storage battery EBU carries out indemnification of reduction of energy of the spark category between electrodes of spark plugs a way:

– Increases in duration of opening of fuel atomizers;
– Increases in frequency of idling;
– Corrections of work of the block of ignition for increase in energy of the spark category.

Mode of switching-off of giving of fuel

At deenergizing of ignition ECU completely stops fuel giving. It excludes possibilities of work of the engine with калильным ignition after ignition deenergizing. Fuel giving also stops in the absence of signals from the ignition block that testify immovabilities of a cranked shaft. It allows to prevent receipt in the Engine of superfluous fuel and infringement of normal work of spark plugs.