Evaporative Emissions - Overview (G1791744): Overview

WARNING: This page is about a different car, the 2015 Jaguar XF, 2014 Jaguar XF, and 2013 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

The EVAP (Evaporative Emission) system reduces the levels of hydrocarbons released into the atmosphere by fuel vapor venting from the fuel tank. The system comprises an EVAP canister, a purge valve and interconnecting vapor pipes. The vapor pipes are connected to the system components using quick release connectors.

NAS (North American Specification) market vehicle have an additional DMTL (Diagnostic Module Tank Leakage) system and a secondary evaporative emission canister. The DMTL system allows the fuel vapor system to be pressurized and detect if a leak is present. The secondary EVAP canister on NAS vehicles uses a higher grade of activated charcoal to meet stricter emission regulations.

Fuel vapor is generated by the fuel in the fuel tank. The amount of fuel vapor produced increases as the fuel temperature rises. Fuel vapor can flow freely into the EVAP canister via the tank venting system.

On NAS & ROW vehicles, the vapor generated in the fuel tank during refueling, flows without restriction into the EVAP canister.

Fuel vapor passes into the EVAP canister where it is absorbed and stored in porous activated charcoal contained within the canister. To prevent the charcoal becoming saturated, the fuel vapor is purged from the canister when the engine is running under certain operating conditions. The ECM (Engine Control Module) operates the Purge Valve at the correct times which allows fuel vapor to be drawn from the canister and burnt in the engine.