Attention: When carrying out maintenance work or replacing parts of the fuel supply system, observe the appropriate safety precautions (see section 1)!
1. Electronic engine management system provides the following features:
- a) Accurate fuel dosage in any operating mode, which ensures low fuel consumption at high power;
- b) Reducing the content of harmful substances in exhaust gases due to accurate fuel dosing and the use of a catalytic converter;
- c) Idle speed and maximum engine speed limit are set and adjusted automatically.
2. Elements of the engine control system maintain high performance for a long time and require virtually no maintenance. Only such elements of the power system as the air and fuel filters need regular replacements during the maintenance of the car.
3. When the diesel engine is running, clean air is sucked into its cylinders. which is compressed to high pressure. In this case, the air temperature rises to 600°C, which exceeds the ignition temperature of diesel fuel. Fuel is injected into the cylinder with some advance and ignites. Thus, spark plugs are not used to ignite the fuel.
4. When operating the vehicle in low ambient temperatures, the temperature of the air inside the cylinders after compression may not be sufficient for self-ignition of the fuel. In this case, it is necessary to preheat the incoming air flow. To do this, glow plugs are installed in the combustion chambers, heating them to the required temperature. The duration of pre-glow depends on the outside temperature and is controlled by the engine management system via a pre-glow relay. When the glow plugs are activated, the corresponding control lamp lights up on the instrument panel (see chapter «Controls and methods of operation», Section 16).
5. Fuel is drawn from the fuel tank by the electric fuel pump and delivered to the high pressure fuel pump (injection pump). Before fuel enters the injection pump, it is cleaned in the fuel filter from contaminants and water. The injection pump creates very high fuel pressure in the injection system even at low speeds. From the injection pump, fuel is supplied through the distribution line to the cylinder injectors.
6. For diesel engines, there are three fuel injection methods: swirl chamber injection, pre-chamber injection and direct injection.
7. With vortex chamber and pre-chamber methods, fuel is injected into the preliminary chamber (prechamber) of the corresponding cylinder where it mixes with air and creates a ready-made working mixture, while part of the fuel immediately ignites and burns out. Due to the turbulence of the air flow and heating during the combustion of part of the fuel, the working mixture becomes more homogeneous and heated. This ensures the completeness of combustion of fuel when it enters the cylinder and a higher efficiency of the engine cycle. The main disadvantage of these injection methods is the complexity of the engine design. Direct injection continues to be the most common and most economical.
8. With direct injection, fuel enters directly into the combustion chamber through the injector nozzle. Each atomizer has, as a rule, 4-6 very thin holes, drilled at different angles, through which the fuel is sprayed in specially given directions. Usually there is a swirl chamber in the bottom of the piston. Swirl chambers can have a different shape, which is consistent with the directions of fuel spraying, contributes to better mixture formation and more efficient combustion of the working mixture.
9. Direct injection on Astra/Zafira models is used «Common Rail» - common for all cylinders fuel distribution line (see resist. illustration). It relieves the injection pump from the function of distributing the fuel, which allows the pump to create a higher pressure - on models with an engine displacement of 1.7 l, the maximum injection pressure is approximately 1400 bar, and on other engines - approximately 1600 bar - this contributes to a very fine atomization of the fuel, due to which improves the process of mixture formation in the cylinders and increases the efficiency of combustion of the working mixture. fuel distribution line (Common Rail) made in the form of a manifold, from which fuel is supplied to individual nozzles.
16.9 Common rail injection system (engines Z13DTH/Z19DT (H))
1 fuel filter
2 Pressure regulator
3 High pressure fuel pump
4 Fuel distribution line (Common-Rail)
5 Pressure sensor
6 Nozzle
7 Fuel tank
8 Electric fuel pump
9 Engine management electronic module
Dashed arrows - direction of electrical signals
Short arrows - direction of fuel flow
10. The engine is equipped with injectors with electromagnetic controls that receive signals from the engine management system, which regulates the amount of fuel supplied to the cylinder.
11. HPFP does not require special maintenance work. All moving parts of the fuel system are lubricated with diesel fuel. The injection pump is driven from the crankshaft through the timing belt.
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