What is an Automotive Active Purge Pump?

The main purpose of an active purge pump is to purge or remove any accumulated fuel vapors from the charcoal canister and route them into the engine intake tract to be burned during operation. This helps keep the charcoal canister empty and prevents emissions from escaping into the atmosphere.

Components of an Active Purge Pump System

The main components of an active purge pump system include:

- Charcoal Canister: Acts as a storage container for hydrocarbon vapors from the fuel tank. It contains activated charcoal that absorbs fuel vapors.

- Purge Valve: Electrically controlled valve that regulates flow between charcoal canister and intake manifold.

- Active Purge Pump: Small electric pump that draws out purged vapors from canister and pushes them into intake manifold.

- Evaporative Emissions (EVAP) System Control Module: Computer that monitors system and controls purge pump and purge valve operation.

- Vacuum Lines/Pipes: Connects canister, purge valve and pump to route vapors.

- Fuel Tank: Source of fuel vapors absorbed by charcoal canister during refueling/temperature changes.

How Does an Active Purge Pump Work?

During normal vehicle operation, the EVAP control module switches on the purge pump periodically to purge stored vapors from the charcoal canister. Here are the basic steps:

- Pump draws out fuel vapors trapped in the canister through its inlet port.

- Purge valve opens simultaneously to connect canister outlet to intake manifold.

- Pump then pressurizes and pushes the purged vapors into the open intake tract through the purge valve.

- Vapors get mixed with air and burnt along with fuel inside the engine combustion chambers.

- This empties the canister and prevents emissions from escaping into the atmosphere through leaks.

- Process repeats continuously to maintain canister at near-zero vapor storage levels.

Factors Automotive Active Purge Pump Operation

Some key factors that influence Automotive Active Purge Pump and purging include:

- Engine operating conditions - Purging only happens when engine is running above a threshold temperature.

- Vehicle speed - Higher speeds allow for better vapor mixing and combustion in cylinders.

- Atmospheric conditions - Temperature, humidity levels affect rate of vapor generation in fuel tank.

- Driving cycle - More frequent purge cycles on short city trips versus highway trips.

- Load on engine - Purging stops under heavy acceleration/loads to avoid lean mixtures.

- Canister load level - Pump runs more when canister is nearing vapor storage capacity limit.

- Diagnostic Trouble Codes (DTCs) - Misfires, leaks may alter standard purging patterns set by ECU.

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