Why Air Injection Pump is Important?
Secondary air injection is also known as air injection which is the vehicle emission control strategy that was introduced first in the mid60s. Well, this is when the fresh air is injected to the exhaust stream to be able to create a fuller combustion of exhaust gases. The mechanism in which the exhaust emission are controlled depend mostly on the injection method and the point at which the air enters the exhaust system and varies during technological advancements.
The first air injected system is close to the engine either in the exhaust ports of the cylinder head or in the exhaust manifold. Such systems provide oxygen to be able to oxidize or burn the unburned and the partially burned fuel in the exhaust prior to ejecting it to tailpipe.
There was actually a massive number of partially burned and unburned fuel in the 60s and 70s cars and for this reason, secondary air injection reduced tailpipe emissions a lot. On the other hand, the extra heat of the recombustion, especially with excessively rich exhaust caused by maladjusted carburetor or misfiring, tended to bring damage to the exhaust valves and even be seen to make the exhaust manifold to incandesce.
Emission control strategies have grown more sophisticatedly and effectively, the volume of partially burned and unburned fuel in exhaust stream shrunk and particularly when the catalytic converter was created, the function of secondary air injection shifted at the same time.
Rather than being the main emission control tool, the secondary air injection was adapted to support the efficient function of catalytic converter. The original air injection point became known as being the upstream injection point. When catalytic converter is cold, the air is injected upstream point that is burnt with deliberately rich exhaust. After the catalyst is warmed up, the air is injected to downstream location, the catalytic converter itself, which then assists with catalysis of the unburned hydrocarbons.
Pumped air injection system uses a vane pump referred as air pump that is turned by the engine using an electric motor or belt. Air intake of the pump is filtered by the rotating screen to be able to exclude dirt particular large enough to bring damage to the system. Then after that, the air is delivered under light pressure to injection point/s. A check valve is going to prevent the exhaust to force its way back into the air injection system which otherwise damage other parts and components. This is why secondary air injection systems play a very important role in vehicles both then and now.