Patent ID: 11971327
Assignee: NISSAN MOTOR CO., LTD.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  G  Y | IPC F  G

Claim 6:
7. An internal combustion engine blowby gas treatment device leak diagnosis device comprising:
an internal combustion engine including a compressor in an intake passage for supercharging;
a blowby gas treatment device including:
a fresh air induction pipe structured to induce fresh air into a crank case from a section of the intake passage downstream of an air flow meter;
a first blowby gas pipe structured to induce blowby gas from the crank case into a section of the intake passage upstream of the compressor;
a second blowby gas pipe structured to induce blowby gas from the crank case into a section of the intake passage downstream of the compressor and downstream of a throttle valve;
a shutoff valve structured to block the fresh air induction pipe; and
a one-way valve structured to allow only a gas flow in the first blowby gas pipe from the crank case to the intake passage; and

a control section configured to diagnose leaking of the blowby gas treatment device, wherein the control section is configured to:
perform a first diagnosis to close the shutoff valve under a non-supercharging condition and determine whether falling of a pressure in the crank case after the closing of the shutoff valve is normal or abnormal;
perform a second diagnosis to determine whether or not a sensed intake air quantity is equal to an actual intake air quantity under the non-supercharging condition, wherein the sensed intake air quantity is a quantity of intake air sensed in the intake passage, and wherein the actual intake air quantity is a quantity of intake air flowing into a cylinder set;
determine presence of a leak to an outside of a system of the blowby gas treatment device, in response to a condition that the first diagnosis determines the falling of the pressure as abnormal and the second diagnosis determines the sensed intake air quantity as unequal to the actual intake air quantity; and
determine presence of a failure within the system of the blowby gas treatment device, in response to a condition that the first diagnosis determines the falling of the pressure as abnormal and the second diagnosis determines the sensed intake air quantity as equal to the actual intake air quantity.