| 摘要 |
A system and method which implements a preferred embodiment of the present invention includes a pump control module for controlling evaporative emissions of engines. In one embodiment, fuel vapor is allowed to accumulate in an intake manifold for a first period of time after an engine is turned off. After the first period of time, the pump control module may open a vacant port and turn on a pump. The pump control module may run the pump for a second period of time. The second period of time may be determined based on the time needed to empty an estimated volume of accumulated fuel vapor from the intake manifold into one or more canisters, such as activated charcoal canisters. After the second period of time, the pump control module may decrease the running time and/or speed of the pump. When the engine is restarted, the vacant port may be closed, the pump may be turned off, and fuel vapor stored in the canisters may be controllably consumed via a purge valve mounted to the intake manifold. In one embodiment, a choke may be placed in between the vacant port and the canisters in order to reduce the number of canisters needed for a given pump size. |
