Introduction to Maserati
4200 Dry Sump Engine
SECONDARY AIR SYSTEM
1.
Solenoid valve
5.
Pneumatic valves duct
2.
Pneumatic valves
6.
Exhaust manifold line
3.
Vacuum tank
7.
Exhaust maniforls
4.
Tank-solenoid valve line
8.
Secundary air pump
This system supplies additional air to the exhaust manifolds to allow the catalytic converter to reach their operating temperature quickly. By means of the solenoid valve (1), the Motronic ECU, drives the opening/closing of the two pneumatic valves (2) which actuate the injection of secondary air into the exhaust manifolds (7). The vacuum tank (3) which creates the vacuum required to open the pneumatic valves is located in the engine compartment, underneath the secondary air pump. The secondary air pump (8), managed by the engine ECU, sends air to the exhaust lines. The pump and the secondary air solenoid valve are activated, after engine ignition, when the coolant temperature is in the range -5 °C to - 99°C. The function is active for around 80 seconds, deactivates for around 60 seconds and then reactivates for a further 10 seconds. In the latter period the secondary air valve seal is monitored. The Lambda sensors are disabled for the entire duration of the cycle.
Maserati Academy
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