Exhaust gas recirculation system

The exhaust gas recirculation system serves to reduce exhaust toxicity (by reducing the formation of nitrogen oxides). At a high combustion temperature of the air-fuel mixture, a large amount of nitrogen oxides is formed in the combustion chamber. Through the recirculation system, part of the exhaust gases is returned to the engine cylinders for their afterburning, which reduces the concentration of the fresh air-fuel mixture and, consequently, the temperature in the combustion chamber.



The main element of the system is a recirculation valve installed at the rear of the cylinder head, which, at large throttle opening angles, allows exhaust gases from the exhaust manifold to burn out into the intake tract through channels in the cylinder head and through the exhaust gas supply pipe. The solenoid valve is controlled by the engine control unit.

The exhaust gas recirculation system does not work under the following conditions:

• low engine coolant temperature;
• engine idling:
• the engine is running at full throttle.

Failure of the valves of the recirculation system leads to an increase in the toxicity of exhaust gases. The valve is non-separable, so if it fails, it is replaced as an assembly.