ZEST/BOLT

ENGINE 1.3L QUADRAJET (90PS)

less air is introduced;

the combustion temperature is reduced (on account

of the presence of inert gases) resulting in a

decrease in the formation of NOx (nitrogen oxides).

The injection control unit is constantly informed of the

quantity of gas recirculated through the information

coming from the flow meter: in effect, if there is an

intake of a certain quantity of air (Qam) for a given

engine speed and the value sent by the flow meter

(Qar) is lower, then the difference (Qgr) is the value for

the quantity of gas recirculated

Qam - Qar = Qgr

Qam - Theoretical quantity of air memorized

Qar - Actual quantity of air

Qgr - Quantity of recirculated gas

The atmospheric pressure signal is used for the

operation of the E.G.R. solenoid valve to recognize

the condition of driving at altitude in order to reduce

the quantity of gas recirculated and to prevent engine

fumes.

A - E.G.R. valve casing

B- Gas intake from exhaust manifold

C - Gas outlet to intake manifold

1 - Solenoid positive, 5 - Solenoid negative

D. E.G.R. SOLENOID VALVE

The Pierburg E.G.R. solenoid valve, fitted on the

cylinder head, has the task of modulating the flow of

exhaust gases to the intake according to the

command from the injection control unit.

This modulation takes place by means of the internal

solenoid, with PWM operation by the control unit,

which activates the control rod via the internal valve

which, once open, directs the gases to the intake

manifold.