Blow-by gas passage abnormality detecting system for internal combustion engines

A blow-by gas passage abnormality detecting system comprising:

• a flow control valve for controlling a flow to pass through a blow-by gas passage to return a blow-by gas produced by an internal combustion engine to an intake passage of said internal combustion engine;
• downstream pressure detecting means arranged in said blow-by gas passage for detecting a pressure downstream of said flow control valve;
• and
• abnormality deciding means for deciding that an abnormality occurs in said blow-by gas passage when the pressure detected by said downstream pressure detecting means is lower than a first predetermined level.

A blow-by gas passage abnormality detecting system comprising:

• a flow control valve for controlling a flow to pass through a blow-by gas passage to return blow-by gas produced by an internal combustion engine to an intake passage of said internal combustion engine;
• upstream pressure detecting means arranged in said blow-by gas passage for detecting a pressure upstream of said flow control valve;
• and
• abnormality deciding means for deciding that an abnormality occurs in said blow-by gas passage when the pressure detected by said upstream pressure detecting means is lower than a first predetermined level.

A blow-by gas passage abnormality detecting system comprising:

• a flow control valve for controlling a flow to pass through a blow-by gas passage to return blow-by gas produced by an internal combustion engine to an intake passage of said internal combustion engine;
• upstream pressure detecting means arranged in said blow-by gas passage for detecting a pressure upstream of said flow control valve;
• intake pressure detecting means for detecting a pressure in said intake passage;
• and
• abnormality deciding means for deciding that an abnormality occurs in said blow-by gas passage, on the basis of the pressure detected by said upstream pressure detecting means and the pressure detected by said intake pressure detecting means.

A blow-by gas passage abnormality detecting system comprising:

• a flow control valve for controlling a flow to pass through a blow-by gas passage to return blow-by gas produced by an internal combustion engine to an intake passage of said internal combustion engine;
• downstream pressure detecting means arranged in said blow-by gas passage for detecting a pressure downstream of said flow control valve;
• intake pressure detecting means for detecting a pressure in said intake passage;
• abnormality deciding means for deciding that an abnormality occurs in said blow-by gas passage, on the basis of the pressure detected by said downstream pressure detecting means and the pressure detected by said intake pressure detecting means;
• and
• control inhibition means for inhibiting a portion of controls of said internal combustion engine when it is decided by said abnormality deciding means that an abnormality occurs in said blow-by gas passage.