Antidissipation apparatus for evaporated fuel vapor

An antidissipation apparatus for evaporated fuel vapor for an internal combustion engine having an intake manifold and a fuel tank comprising:

• a purge passage for connecting said intake manifold and said fuel tank;
• a canister installed in said purge passage for absorbing evaporated fuel vapor which is generated in said fuel tank;
• a motor;
• and
• a purge pump installed in said purge passage for delivering said adsorbed evaporated fuel vapor to said intake manifold, said purge pump being controlled by said motor to change its discharge amount of said adsorbed evaporated fuel vapor to said intake manifold based on operating parameters of said engine;
• wherein said canister further includes an atmospheric passage which vents an upstream side of said canister and a canister control valve which opens or closes said atmospheric passage;
• and
• said purge pump is installed between said canister and said canister control valve.

An antidissipation apparatus for evaporated fuel vapor for an internal combustion engine having an intake manifold and a fuel tank comprising:

• a purge passage for connecting said intake manifold and said fuel tank;
• a canister installed in said purge passage for absorbing evaporated fuel vapor which is generated in said fuel tank;
• a motor;
• and
• a purge pump installed in said purge passage for delivering said adsorbed evaporated fuel vapor to said intake manifold, said purge pump being controlled by said motor to change its discharge amount of said adsorbed evaporated fuel vapor to said intake manifold based on operating parameters of said engine;
• a canister valve located upstream of said canister to open or close an atmospheric passage;
• an internal pressure detector which detects an internal pressure of said purge passage;
• and
• failure diagnosis means for determining a failure of said purge pump under condition that said internal pressure of said purge passage which is detected by said internal pressure detector is higher than a predetermined pressure when said purge pump is in operation and said canister control valve is closed.

An antidissipation apparatus for evaporated fuel vapor for an internal combustion engine having an intake manifold and a fuel tank comprising:

• a purge passage for connecting said intake manifold and said fuel tank;
• a canister installed in said purge passage for absorbing evaporated fuel vapor which is generated in said fuel tank;
• a motor;
• and
• a purge pump installed in said purge passage for delivering said adsorbed evaporated fuel vapor to said intake manifold, said purge pump being controlled by said motor to change its discharge amount of said adsorbed evaporated fuel vapor to said intake manifold based on operating parameters of said engine;
• an engine rotational speed detector which detects rotational speed of said engine;
• failure diagnosis means for determining a failure of said purge pump under condition that a rotational speed difference between a first rotational speed and a second rotational speed is smaller than a predetermined rotational speed difference, said first rotational speed being detected by said engine rotational speed detector when said purge pump is not in operation, said second rotational speed being detected by said engine rotational speed detector when said purge pump is in operation.

An antidissipation apparatus for evaporated fuel vapor for an internal combustion engine having an intake manifold, a fuel passage and a fuel tank comprising:

• a purge passage for connecting said intake manifold and said fuel tank;
• a canister installed in said purge passage for adsorbing evaporated fuel vapor generated in said fuel tank;
• a purge pump installed in said purge passage for delivering said adsorbed evaporated fuel vapor to said intake manifold;
• and
• failure diagnosis means for determining a failure of said purge pump.

An antidissipation method for evaporated fuel vapor for an internal combustion engine having an intake manifold, a fuel tank, a purge passage for connecting said intake manifold and said fuel tank, a canister installed in said purge passage for adsorbing evaporated fuel vapor which is generated in said fuel tank, and a motor driven purge pump installed in said purge passage for delivering a controlled discharge amount of said adsorbed evaporated fuel vapor to said intake manifold based on operating parameters of said engine, said method comprising:

• venting an open or closed atmospheric passage upstream of said canister,
• detecting an internal pressure of said purge passage;
• and
• determining a failure of said purge pump under condition that said internal pressure of said purge passage is higher than a predetermined pressure when said purge pump is in operation and said venting is closed.

An antidissipation method for evaporated fuel vapor for an internal combustion engine having an intake manifold, a fuel passage, a fuel tank, a purge passage connecting said intake manifold and said fuel tank, a canister installed in said purge passage for adsorbing evaporated fuel vapor generated in said fuel tank, and a purge pump installed in said purge passage for delivering said adsorbed evaporated fuel vapor to said intake manifold, said method comprising:

• determining a failure of said purge pump;
• detecting an internal pressure of said purge passage;
• venting an atmospheric passage on an upstream side of said canister to open or close said atmospheric passage;
• and
• determining a failure of said purge pump under condition that said internal pressure of said purge passage is higher than a predetermined pressure when said purge pump is in operation and said venting is closed.

An antidissipation method for evaporated fuel vapor for an internal combustion engine having an intake manifold, a fuel passage, a fuel tank, a purge passage connecting said intake manifold and said fuel tank, a canister installed in said purge passage for adsorbing evaporated fuel vapor generated in said fuel tank, and a purge pump installed in said purge passage for delivering said adsorbed evaporated fuel vapor to said intake manifold, said method comprising:

• determining a failure of said purge pump;
• detecting rotational speed of said engine;
• and
• determining a failure of said purge pump under condition that a rotational speed difference between a first rotational speed when said purge pump is not in operation, and a second rotational speed when said purge pump is in operation is smaller than a predetermined rotational speed difference.