Fuel is sucked in by the high pressure fuel pump (injection pump) directly from the tank. In the injection pump, the fuel is compressed to the pressure required for injection. Injection is carried out in the same order as the ignition order in a gasoline engine.
When the fuel supply approaches the end, - a signal lamp lights up on the instrument panel, - the car should be refueled without delay.
In order to reduce the toxicity of exhaust gases, a catalytic converter is included as standard on all diesel models. At the same time, the recirculation system provides a significant reduction in the content of nitrogen oxides in the exhaust gases, part of the exhaust gases is mixed with the air sucked into the engine, which reduces the oxygen concentration in it and, accordingly, reduces the ignition delay and lowers the combustion temperature. The result of all these processes is to minimize the formation of nitrogen oxides in the combustion products (NOx). The exhaust gas recirculation process requires precise dosage, otherwise the level of carbon particles in the combustion products increases (soot). The dosage is carried out by including a special meter in the system circuit - the information coming from the meter allows the electronic module to control the recirculation process.
Fuel is injected into the prechambers of the cylinders. The injection pump is electronically controlled, which guarantees compliance with stringent modern requirements for the content of toxic components in the exhaust gases of the engine. The brain of the control system is an electronic module built into the pump assembly that continuously analyzes the data coming from a whole complex of information sensors:
- Accelerator pedal position sensor - informs the control units about the position of the gas pedal;
- coolant temperature sensor (ECT) - informs the control units about the operating temperature of the engine;
- Air mass meter sensor (MAF) -- informs the control units about the mass and temperature of the air sucked into the intake duct;
- crankshaft position sensor (CKP) -- informs the control units about the position and speed of rotation of the crankshaft;
- boost pressure sensor – informs the control units about the pressure in the inlet pipeline (with appropriate equipment);
- Injection pump sensors and regulators (built-in) - are used by control units when calculating and controlling the moments and the amount of fuel injected into the engine;
- clutch sensor - used by control units when performing tempostat functions;
- K/V activation sensor-switch – informs the control units about turning the air conditioner on or off (with appropriate equipment).
All data received from information sensors is processed by electronic control units that, based on its analysis, control the moments and quantity of fuel injection, ensuring optimal performance of the power unit, regardless of changes in external factors. The engine ECM controls the injection timing through the injection pump control unit, ensuring reliable engine start at any ambient temperature, its fastest warm-up, as well as maximum efficiency in all driving modes, including acceleration and engine braking.
The basic setting of the injection points is made when the injection pump is mounted on the engine. During the operation of the unit, changes in this characteristic occur automatically at the ECM commands through the cam actuator.
The dosage of the fuel supplied to the engine is carried out using the quantity and injection timing valves built into the high-pressure fuel pump. The valves are actuated by commands issued by the injection pump control unit, usually located at the top of the pump. A special ring is installed on the main rotor of the injection pump. The rotor position sensor detects the position and speed of the rotor. The sensor works on the same principle as the crankshaft position sensor. Four marks are applied to the rotor - in accordance with the number of cylinders. The pump control unit receives the necessary information from the engine control unit (ECM) and calculates the moments and duration of fuel supply. The internal components of the injection pump allow these parameters to be calculated very accurately, which ultimately leads to an increase in the efficiency of the engine's return and a decrease in exhaust gas toxicity.
There is no gas cable on diesel models - its functions are performed by the accelerator pedal position sensor. The sensor continuously informs the control unit about the position of the pedal, which allows the ECM to accurately calculate injection parameters. The idle speed is also regulated by the control unit and is not subject to manual adjustment. By analyzing information from various sensors, the control unit calculates the number of revolutions, correcting them depending on the load and engine temperature.
The pump is connected to nozzles metal pipes. Each nozzle delivers fuel to the combustion chambers through five holes. This achieves an even distribution of fuel in the combustion chamber and an accurate direction of the fuel supply. The fuel injection system is a direct injection system. The bottoms of the pistons are vortex chambers, providing a swirl of the fuel entering the combustion chambers. Injectors open in two stages to optimize fuel combustion (for this, there are two springs inside each nozzle). When the injector is opened, a small amount of fuel is drawn onto the internal components of the injector, lubricating them, and returns to the fuel tank.
The heating of a cold engine is controlled by the engine control unit and the injection pump control unit. When the engine is cold, the injection timing is shifted by the injection pump control unit. The engine control unit, in turn, controls the operation of the glow plugs. glow plugs installed in each cylinder and turn on before starting the engine, working while cranking the engine with a starter and for some time after starting the engine. Spark plugs make it much easier to start a cold engine. After the ignition is turned on, the control lamp on the dashboard lights up (see chapter Controls and methods of operation), signaling the inclusion of glow plugs. As soon as the lamp goes out, you can begin to start the engine. In very cold weather, the spark plugs continue to work for some time after the engine is started, ensuring the stability of the latter and reducing the level of toxic components in the exhaust gases.
If the sensors receive information indicating the occurrence of a non-emergency situation, the ECM switches to emergency operation mode, when the base values of the corresponding parameters are substituted for inadequate signals - the efficiency of the engine output in this mode naturally decreases. When the ECM enters the driver's emergency mode, the failure warning lamp on the vehicle's instrument panel warns (see chapter Controls and methods of operation at the beginning of the guide), the corresponding diagnostic code is entered into the processor memory (see chapter Engine Electrical Systems).
Under certain circumstances, the behavior of the car may not change at all. The only sign that the ECM has gone into emergency mode may be an increase in exhaust emissions.
Keep in mind that after replacing a faulty sensor with a working one, the system will not automatically return to normal mode on its own - you should clear the processor memory of the diagnostic codes contained in it. Even if the reason for the transition of the system to the emergency safe mode was a broken wiring, after it the processor memory should be cleared.
When the warning lamp comes on, the car should be driven to an Opel authorized service station as soon as possible for detailed diagnostics using special equipment and the necessary remedial repairs.
Diagnostic equipment (scanner type reader) It is connected to the DLC connector located under the decorative trim under the front of the parking brake lever.
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