Leakage diagnosing device for fuel evaporated gas purge system

A leakage diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbed evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising:

• leakage diagnosing means for diagnosing puree system leakage based on a detected pressure change amount and an introduced pressure which is introduced into a part of the purge system including at least the fuel tank and the canister, said detected pressure change amount being obtained by detecting pressure in said part of the purge system after said part of the purge system is hermetically sealed, wherein said leakage diagnosing means further includes:
• comparison means for comparing said detected pressure change amount with a determination value;
• and
• compensation means for compensating said determination value based on said introduced pressure.

A leakage diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbed evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising:

• leakage diagnosing means for diagnosing purge system leakage based on a detected pressure change amount and an introduced pressure which is introduced into a part of the purge system including at least the fuel tank and the canister, said detected pressure change amount being obtained by detecting pressure in said part of the purge system after said part of the purge system is hermetically sealed, wherein;
• said leakage diagnosing means includes evaporated gas concentration determination means for determining an evaporated gas concentration from a ratio of an air fuel ratio feedback compensation amount deviation to a purge ratio during a purge execution;
• and
• said leakage diagnosing means further includes execution condition determining means for determining one of an execution and a non-execution of said purge system leakage diagnosis by comparing a change amount of said evaporated gas concentration with a comparison value.

A leakage diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbed evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising:

• leakage diagnosing means for diagnosing puree system leakage based on a detected pressure change amount and an introduced pressure which is introduced into a part of the purge system including at least the fuel tank and the canister, said detected pressure change amount being obtained by detecting pressure in said part of the purge system after said part of the purge system is hermetically sealed, wherein;
• said leakage diagnosing means includes evaporated gas concentration determination means for determining an evaporated gas concentration from a ratio of an air fuel ratio feedback compensation amount deviation to a purge ratio during a purge execution;
• and
• said leakage diagnosing means further includes execution condition determining means for determining one of an execution and a non-execution of said purge system leakage diagnosis by comparing both a change amount of said evaporated gas concentration and said evaporated gas concentration with a comparison value.

A leakage diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbed evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising:

• leakage diagnosing means for diagnosing purge system leakage based on a detected pressure change amount and an introduced pressure which is introduced into a part of the purge system including at least the fuel tank and the canister, said detected pressure change amount being obtained by detecting pressure in said part of the purge system after said part of the purge system is hermetically sealed, wherein;
• said leakage diagnosing means includes evaporated gas concentration determination means for determining an evaporated gas concentration from a ratio of a purge ratio to an air fuel ratio feedback compensation amount deviation during a purge execution;
• said leakage diagnosing means further includes execution condition determining means for determining one of an execution and a non-execution of said purge system leakage diagnosis by comparing said evaporated gas concentration with a comparison value;
• and
• said leakage diagnosing means further includes comparison value determination means for determining said comparison value based on at least one of an engine cooling water, elapsed time after an engine start, and accumulated time of said purge execution.

A leakage diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbed evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising:

• leakage diagnosing means for diagnosing purge system leakage based on a detected pressure chance amount and an introduced pressure which is introduced into a part of the purge system including at least the fuel tank and the canister, said detected pressure change amount being obtained by detecting pressure in said part of the purge system after said part of the purge system is hermetically sealed, wherein;
• said apparatus includes fuel consumption determining means for determining a fuel amount consumed by the engine, and remaining fuel determining means for determining one of a remaining fuel amount and an air amount in said fuel tank;
• and
• said leakage diagnosis means compensates one of said detected pressure and said detected pressure change amount based on both the consumed fuel amount determined by said fuel consumption determining means and said one of a remaining fuel amount and an air amount in said fuel tank determined by said remaining fuel determining means.

An abnormality diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbing evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising;

• abnormality diagnosing means for diagnosing purge system abnormality based on one of a detected pressure and a detected pressure change amount in a part of the purge system including at least the fuel tank and the canister, said one of said detected pressure and said detected pressure change amount being obtained by detecting pressure in said part of the purge system after sealing said part of the purge system hermetically, and wherein;
• said abnormality diagnosing means includes evaporated gas concentration determination means for determining an evaporated gas concentration from a ratio of an air fuel ratio feedback compensation amount deviation to a purge ratio during a purge execution;
• and
• said abnormality diagnosing means further includes execution condition determining means for determining one of an execution and a non-execution of said purge system abnormality diagnosis by comparing at least one of said determined evaporated gas concentration and a change amount of said evaporated gas concentration with a comparison value.

A leakage diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbing evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising;

• leakage diagnosing means for diagnosing purge system leakage based on one of a detected pressure and a detected pressure change amount in a part of the purge system including at least the fuel tank and the canister, said one of said detected pressure and said detected pressure change amount being obtained by detecting pressure in said part of the purge system after sealing said part of the purge system hermetically;
• and
• fuel consumption determining means for determining a fuel amount consumed by the engine;
• wherein
• said leakage diagnosis means compensates one of said detected pressure and said detected pressure change amount based on said consumed fuel amount determined by said fuel consumption determining means.