- Exhaust gas recirculation system and throttle valve - reduction of NOx, as well as reduction of soot in the exhaust gas (black smoke).
- Oxidative neutralizer - reducing the content of NOx, CH, CO.
The engine has a forced crankcase ventilation system. The system serves to remove exhaust gases that have escaped from the combustion chamber into the crankcase. To do this, a hose connected to the intake manifold is connected to the cylinder head cover. The crankcase gases enter the intake manifold through the hose, and then into the combustion chamber.
The location of the components of the toxicity reduction system.
1 - exhaust gas recirculation valve,
2 - cooler of the exhaust gas recirculation system,
3 - throttle valve,
4 - solenoid valve of the exhaust gas recirculation system,
5 - control solenoid valve of the exhaust gas recirculation system,
6 - air filter,
7 - solenoid valve No. 1 throttle control,
8 - solenoid valve No. 2 throttle control,
9 - oxidative neutralizer.
Exhaust gas cooling in the cooler of the exhaust gas recirculation system.
Exhaust gas recirculation system (EGR)
EGR Exhaust gas recirculation system (Exhaust gas recirculation) serves to reduce the toxicity of exhaust gases by afterburning nitrogen oxides NO in the combustion chamber.
The system consists of an EGR valve with position sensor, two solenoid valves, a cooler and a pipe system.
With the help of a cooler, the temperature of the exhaust gases is reduced, which is necessary to prevent heating of the air when it is mixed with the exhaust gases entering the intake and, accordingly, to improve the filling of the cylinders and reduce the smoke of the exhaust gases.
Exhaust gases in the EGR cooler are cooled by coolant supplied to the cooler from the engine cooling system.
The exhaust gas recirculation system is controlled by the engine control unit using solenoid valves. Solenoid valve No. 1 is installed in the system (vacuum valve) and solenoid control valve No. 2 (ventilation valve), the engine control unit controls the opening of the EGR valve using both solenoid valves. On a signal from the control unit, the solenoid valves open and close, supplying a vacuum to the valve diaphragm or a vacuum from a vacuum pump (through a solenoid vacuum valve) or atmospheric pressure (through a vent valve connected to the atmosphere). By opening the exhaust gas recirculation valve, the amount of exhaust gases passed into the intake manifold and further into the combustion chamber is regulated. Afterburning of NOx takes place in the combustion chamber.
The calculation of the required opening of the EGR valve is made by the engine control unit based on the engine speed, fuel cycling and the readings of the mass air flow sensor.
To optimize the operation of the exhaust gas recirculation system, it is necessary to adjust the parameters of the mass air flow sensor, which change depending on the service life of the sensor (see chapter "fuel injection system", chapter "The engine control unit").
Exhaust gas recirculation valve.
1 - from the EGR cooler,
2 - to the intake manifold.
To improve the operation of the exhaust gas recirculation system, a pneumatic throttle valve is installed in the intake tract, controlled by the engine control unit using two solenoid valves. When the EGR system is activated, the throttle valve closes, as a result of which an additional vacuum is created in the intake manifold, which improves the flow of exhaust gases from the ESI system into the combustion chamber.
When the engine is idling, the throttle valve is also covered, which helps to reduce intake air noise.