Vehicles with a 1.6-/2.0-liter petrol engine
The electronic multipoint injection system has four injectors, one for each cylinder. The injectors inject fuel into the intake valves sequentially, each one individually according to the engine's firing order. For a 1.6 liter engine (K7M) injection occurs semi-sequentially. This means that injectors I and 4.2 and 3 cylinders fire simultaneously. The current position of the cylinder pistons is reported to the control unit by two pulse sensors. One sensor is located on the flywheel, and the other registers the position of the camshaft.
Fuel from the fuel tank is taken by an electric fuel pump and fed through the fuel filter to the fuel distribution line, and from it to the injectors. The pressure reducing valve on the fuel distribution line maintains the pressure in the fuel system at a constant level of 3 bar.
The main indicator that determines the volume of injected fuel for the control unit is the vacuum in the intake manifold. This vacuum depends on the throttle opening angle at the current moment, as well as on the number of engine revolutions. These two indicators are a measure of the amount of air taken in. The intake manifold pressure sensor is located on the bulkhead of the engine compartment and is connected to the intake manifold by a hose (see illustration 1.0a).
1.0a Engine compartment of a car with a 1.6 liter petrol engine (K7M): I - control unit; 2 - detonation combustion sensor; 3 - coolant temperature indicator sensor; 4 - TDC sensor; 5-adsorber valve; 7 - idle speed regulator; 8 - throttle potentiometer; 9 - intake air temperature sensor; 10 - pressure sensor in the intake manifold; 11 - adsorber; 12 - ignition coil of cylinders 1 and 4; 13 - ignition coil of cylinders 2 and 3; 14 - fuel pump relay; 15 - noise suppression capacitor; 16 - air filter; 17 - lambda probe (oxygen sensor); 18 - sensor-switch of the power steering; 19 - exhaust gas recirculation valve; 20 - air pump; 21 - air filter
Additional information regarding the throttle opening angle is supplied to the control unit from the potentiometer. This information serves as a comparative value for the volume of incoming air. It is needed in order for the control unit to respond to changes in the nature of movement, for example, to acceleration, or it is used when the control unit switches to the execution of the so-called emergency program in the event of a failure of the pressure sensor in the intake manifold.
The ignition and injection control unit, based on information about the volume of incoming air and engine speed at the current moment, sets the duration of injection and, thereby, the amount of injected fuel, guided by the embedded parametric data. If the injectors remain open for a longer period of time, then the volume of injected fuel also increases. Additional sensors regulate the amount of fuel in relation to the corresponding load on the engine at the current moment.
The idle air control sensor informs the control unit of the throttle position at idle. The control unit through the regulator brings the idle speed to the nominal values.
The idle speed controller, which is a solenoid valve, regulates the air supply bypassing the throttle, which stabilizes the idle speed in all conditions and under any load.
The coolant temperature indicator sensor located in the exhaust pipe measures the temperature of the engine, and the air temperature sensor in the intake manifold measures the temperature of the air taken in by the engine.
The oxygen sensor is screwed into the exhaust pipe of the mufflers and measures the oxygen content in the exhaust gas. Based on the information received from this sensor, the control unit keeps the composition of the exhaust gases in the most acceptable parameters for the sensor.
The fuel tank vent solenoid valve is activated depending on the engine load. Fuel vapors from the tank are captured by the adsorber, which is a container with activated carbon, and through the solenoid valve are fed into the engine for combustion.
Vehicles with 1.6 liter engine and 16 valve engine
The EGR valve is located in the exhaust manifold and opens when the engine is hot to let in a certain amount of fresh air, which is mixed with the exhaust gas. This is to ensure that this air is burned before the exhaust gases enter the catalytic converter. Thus, a reduction in harmful carbon oxides in the exhaust gases is achieved.