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Solar Wizard
- Joined
- Nov 14, 2021
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The purpose of air pumps on modern cars is to help reduce catalytic converter warm-up time. Oxygen sensors are heated for the same reason.
Earlier cars, the air was actually injected right after the exhaust valve after the car had warmed up to help combust partially and unburned fuel...kind of a crude 2-way catalyst effect.
Newer cars have their emissions measured by the mile and part of that testing process involves measuring emissions from a cold-start so that is why they focus quite a bit of energy getting the catalytic converters up to operating temp. Also, that means that things like larger tires have an impact on measured emissions.
In other words emissions are a function of the amount of fuel burned to go a mile whereas in the past, they were only concerned about what percentage of the exhaust HC, Co and Nox made up.
Earlier cars, the air was actually injected right after the exhaust valve after the car had warmed up to help combust partially and unburned fuel...kind of a crude 2-way catalyst effect.
Newer cars have their emissions measured by the mile and part of that testing process involves measuring emissions from a cold-start so that is why they focus quite a bit of energy getting the catalytic converters up to operating temp. Also, that means that things like larger tires have an impact on measured emissions.
In other words emissions are a function of the amount of fuel burned to go a mile whereas in the past, they were only concerned about what percentage of the exhaust HC, Co and Nox made up.