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EXHAUST SYSTEM
The 912 E engines are equipped with a secondary air injection, thermal reactors and EGR.
The muffler and heat exchangers are also new.
The secondary air injection and the thermal reactors are designed to reduce the CO and HC emission
in the exhaust. The purpose of the EGR is to reduce the emission of nitric oxide (NO
x ).
Secondary Air Injection
The air required for after burning the exhaust gases
is supplied to the exhaust manifold by means of a
motor driven air pump
.
The air from the pump (1) is pumped via a back-up
valve (2) and a distributor line (3) to the air
injection valve (4) which is located immediately
behind the exhaust valve. The exhaust gas after
burning takes place in the thermal reactor (5)
.
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