Detecting device and method of an abnormality in an air-fuel ratio control system

Claim 1

A device for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors for detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the device which comprises: judging means responsive to said engine operating condition signal for deciding whether said various sensors operate normally and for generating a normal signal if each output of said various sensors is in each predetermined normal range; deciding means responsive to said normal signal for judging whether said engine operating condition is satisfied with every condition for diagnosis and for producing a diagnosis signal; determining means responsive to said diagnosis signal for judging whether said engine is controlled in a closed-loop operation and for outputting a closed-loop signal; learning control means responsive to said closed-loop signal for comparing a number of grids being renewed said data in said memory with a predetermined number and for generating a number signal when said number is larger than said predetermined number; calculating means responsive to said a number signal for computing a difference between corrected values in said memory and for producing a difference signal; comparing means responsive to said difference signal for comparing said difference signal with a predetermined difference and for generating an abnormal signal if said difference signal is larger than said both predetermined difference; and warning means responsive to said abnormal signal for indicating an abnormality of said intake air measurement system and for storing said abnormality in a backup RAM in said memory so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.

Claim 2

A device for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors for detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the device which comprises: judging means responsive to said engine operating condition signal for deciding whether said various sensors operate normally and for generating a normal signal if each output of said various sensors is in each predetermined normal range; deciding means responsive to said normal signal for judging whether said engine operating condition is satisfied with every condition for diagnosis and for producing a diagnosis signal; determining means responsive to said diagnosis signal for judging whether said engine is controlled in a closed-loop operation and for outputting a closed-loop signal; learning control means responsive to said closed-loop signal for comparing a number of grids being renewed said data in said memory with a predetermined number and for generating a number signal when said number is larger than said predetermined number; calculating means responsive to said a number signal for computing a difference between corrected values in said memory and for producing a difference signal; comparing means responsive to said difference signal for comparing said difference signal with a predetermined difference and for generating an abnormal signal if said difference signal is larger than said both predetermined difference; and warning means responsive to said abnormal signal for indicating an abnormality of said intake air measurement system and for storing said abnormality in a backup RAM in said memory so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.

Claim 3

A device for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors for detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the device which comprises: judging means responsive to said engine operating condition signal for deciding whether said various sensors operate normally and for generating a normal signal if each output of said various sensors is in each predetermined normal range; deciding means responsive to said normal signal for judging whether said engine operating condition is satisfied with every condition for diagnosis and for producing a diagnosis signal; determining means responsive to said diagnosis signal for judging whether said engine is controlled in a closed-loop operation and for outputting a closed-loop signal; learning control means responsive to said closed-loop signal for comparing a number of grids being renewed said data in said memory with a predetermined number and for generating a number signal when said number is larger than said predetermined number; calculating means responsive to said a number signal for computing a difference between corrected values in said memory and for producing a difference signal; comparing means responsive to said difference signal for comparing said difference signal with a predetermined difference and for generating an abnormal signal if said difference signal is larger than said both predetermined difference; and warning means responsive to said abnormal signal for indicating an abnormality of said fuel injection system and for storing said abnormality in a backup RAM in said memory so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.

Claim 4

A device for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors for detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the device which comprises: judging means responsive to said engine operating condition signal for deciding whether said various sensors operate normally and for generating a normal signal if each output of said various sensors is in each predetermined normal range; deciding means responsive to said normal signal for judging whether said engine operating condition is satisfied with every condition for diagnosis and for producing a diagnosis signal; determining means responsive to said diagnosis signal for judging whether said engine is controlled in a closed-loop operation and for outputting a closed-loop signal; learning control means responsive to said closed-loop signal for comparing a number of grids being renewed said data in said memory with a predetermined number and for generating a number signal when said number is larger than said predetermined number; calculating means responsive to said a number signal for computing a difference between corrected values in said memory and for producing a difference signal; comparing means responsive to said difference signal for comparing said difference signal with a predetermined difference and for generating an abnormal signal if said difference signal is larger than said both predetermined difference; and warning means responsive to said abnormal signal for indicating an abnormality of said fuel injection system and for storing said abnormality in a backup RAM in said memory so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.

Claim 5

A method for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors ±or detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the method which comprises the steps of: deciding whether said various sensors operate normally and whether each output of said various sensors is in each predetermined normal range; judging whether said engine operating condition is satisfied with every condition for diagnosis diagnosis signal; determining whether said engine is controlled in a closed-loop operation; comparing a number of grids being said memory with a predetermined number; calculating a difference between corrected values in said memory; comparing said difference if said difference is larger than said both predetermined difference; and warning an abnormality of said intake air measurement system so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.

Claim 6

A method for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors ±or detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the method which comprises the steps of: deciding whether said various sensors operate normally and whether each output of said various sensors is in each predetermined normal range; judging whether said engine operating condition is satisfied with every condition for diagnosis diagnosis signal; determining whether said engine is controlled in a closed-loop operation; comparing a number of grids being said memory with a predetermined number; calculating a difference between corrected values in said memory; comparing said difference if said difference is larger than said both predetermined difference; and warning an abnormality of said intake air measurement system so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.

Claim 7

A method for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors for detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the method which comprises the steps of: deciding whether said various sensors operate normally and whether each output of said various sensors is in each predetermined normal range; judging whether said engine operating condition is satisfied with every condition for diagnosis diagnosis signal; determining whether said engine is controlled in a closed-loop operation; comparing a number of grids being renewed said data in said memory with a predetermined number; calculating a difference between corrected values in said memory; comparing said difference if said difference is larger than said both predetermined difference; and warning an abnormality of said fuel injection system so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.

Claim 8

A method for detecting an abnormality in an air-fuel control system mounted on an engine having, an intake air measurement system mounted in an intake pipe for measuring an amount of induced air into said engine, a fuel injection system for injecting a fuel into a cylinder, an air-fuel ratio sensor inserted in an exhaust pipe for detecting an air-fuel ratio near a catalyst, various sensors for detecting an engine operating condition and for generating an engine operating condition signal, and control means responsive to said engine operation signal for controlling said engine with data stored in a memory by a learning control, an improvement of the method which comprises the steps of: deciding whether said various sensors operate normally and whether each output of said various sensors is in each predetermined normal range; judging whether said engine operating condition is satisfied with every condition for diagnosis diagnosis signal; determining whether said engine is controlled in a closed-loop operation; comparing a number of grids being renewed said data in said memory with a predetermined number; calculating a difference between corrected values in said memory; comparing said difference if said difference is larger than said both predetermined difference; and warning an abnormality of said fuel injection system so as to precisely and promptly identify said abnormality from that of deterioration of said sensors.