General description

Evaporative Emission Control (EVAP) system

B EVAP system - VVT-i models

A Typical EVAP system and operation chart - Non-VVT-i models

1 This system is designed to trap and store fuel that evaporates from the fuel tank, throttle body and intake manifold that would normally enter the atmosphere in the form of hydrocarbon (HC) emissions.

2 The Evaporative Emission Control (EVAP) system for non-VVT-i engines consists of a charcoal-filled canister, the lines connecting the canister to the fuel tank, the Temperature

Vacuum Valve (TVV) and a check valve (see illustration). On VVT-i engines, the systemconsists of a charcoal-filled canister, the pipes connecting the canister to the fuel tank, the Vacuum Switching Valve (VSV) and a surge tank (see illustration).

3 Fuel vapours are transferred from the fuel tank and throttle body to a canister where they're stored when the engine isn't running. When the engine is running, the fuel vapours are purged from the canister by intake airflow and consumed in the normal combustion process.

4 The charcoal canister is equipped with a check valve that incorporates three check balls. Depending upon the running conditions and the pressure in the fuel tank, the check balls open and close the passageways to the

TVV/VSV (consequently the throttle body) and fuel tank.

Дата добавления: 2014-12-23