Misfiring detector for internal combustion engines

Claim 2

In an internal combustion engine having at least one combustion chamber, an exhaust system including an exhaust port opening to said combustion chamber, an exhaust manifold, two exhaust pipes connected with said exhaust manifold, and an exhaust gas purifying means disposed in one of said exhaust pipes; a protective system for preventing said exhaust gas purifying means from being destroyed by unburned gas emitted from said combustion chamber in the event that a misfire occurs in said combustion chamber, which system comprises: a gas current pulse generator disposed in said exhaust manifold in the vicinity of said exhaust port, said gas current pulse generator having electrodes forming an ion-gap for generating gas current pulse signal when a high temperature burned gas is emitted through said ion-gap from said combustion chamber; an engine speed sensor driven by said engine for producing an engine pulse signal with a repetition rate proportional to the speed of said engine; an electronic computing means responsive to said gas current pulse signal and said engine speed pulse signal to produce an electric output signal representing the occurrence of the misfire when the ratio of the number of said gas current pulse signal to that of said engine speed pulse signal is less than a predetermined value; bypass valve means disposed in said exhaust pipes for preventing said unburned gas from passing through said exhaust gas purifying means; a solenoid actuator for actuating said bypass valve means; and electric energizing means for energizing said solenoid actuator in response to said output signal from said electronic computing means and storing a misfiring condition.

Claim 3

In an internal combustion engine as claimed in claim 1, said electric energizing means is a relay switch of a self-holding type to thereby store a misfiring condition.

Claim 4

In an internal combustion engine as claimed in claim 1, said electronic computing means includes a self-holding circuit for storing a misfiring condition.

Claim 5

In an internal combustion engine having at least one combustion chamber, an exhaust system including an exhaust port opening to said combustion chamber, an exhaust manifold and an exhaust pipe connected to said exhaust manifold, an exhaust gas purifying means disposed in said exhaust pipe, and a secondary air supply system including an air cleaner, an air pump for sucking air filtered through said air cleaner and a secondary air supplying pipe with a one-way check valve for supplying a secondary air from said air pump into said exhaust manifold through a nozzle; a protective system for preventing said exhaust gas purifying means from being destroyed by unburned gas emitted from said combustion chamber in the event that a misfire occurs in said combustion chamber comprising: a gas current pulse generator disposed in said exhaust manifold in the vicinity of said exhaust port, said gas current pulse generator having electrodes forming an ion-gap for generating a gas current pulse signal when a high temperature burned gas is emitted through said ion-gap from said combustion chamber; an engine speed sensor driven by said engine for producing an engine speed pulse signal with a repetition rate proportional to the speed of said engine; an electronic computing means responsive to said gas current pulse signal and said engine speed pulse signal to produce an electric output signal representing the occurrence of the misfire when the ratio of the number of said gas current pulse signal to that of said engine speed pulse signal is less than a predetermined value; a secondary air supply control means for preventing said secondary air from being drawn into said exhaust gas purifying means, said control means comprising a bypass valve means disposed in said secondary air supplying pipe for feeding back said secondary air into said air pump through a bypass passageway communicating between said secondary air supplying pipe and said air pump and a solenoid actuator for actuating said bypass valve means; and electric energizing means for energizing said solenoid actuator in response to said output signal from said electronic computing means and storing a misfiring condition.

Claim 6

In an internal combustion engine having at least one combustion chamber, an exhaust system including an exhaust port opening to said combustion chamber, an exhaust manifold and an exhaust pipe connected to said exhaust manifold, an exhaust gas purifying means disposed in said exhaust pipe, and a secondary air supply system including an air cleaner, an air pump for sucking air filtered through said air cleaner and a secondary air supplying pipe with a one-way check valve for supplying a secondary air from said air pump into said exhaust manifold through a nozzle; a protective system for preventing said exhaust gas purifying means from being destroyed by unburned gas emitted from said combustion chamber in the event that a misfire occurs in said combustion chamber comprising: a gas current pulse generator disposed in said exhaust manifold in the vicinity of said exhaust port, said gas current pulse generator having electrodes forming an ion-gap for generating a gas current pulse signal when a high temperature burned gas is emitted through said ion-gap from said combustion chamber; an engine speed sensor driven by said engine for producing an engine speed pulse signal with a repetition rate proportional to the speed of said engine; an electronic computing means responsive to said gas current pulse signal and said engine speed pulse signal to produce an electric output signal representing the occurrence of the misfire when the ratio of the number of said gas current pulse signal to that of said engine speed pulse signal is less than a predetermined value; a secondary air supply control means for preventing said secondary air from being drawn into said exhaust gas purifying means, said control means comprising a bypass valve means disposed in said secondary air supplying pipe for feeding back said secondary air into said air pump through a bypass passageway communicating between said secondary air supplying pipe and said air pump and a solenoid actuator for actuating said bypass valve means; and electric energizing means for energizing said solenoid actuator in response to said output signal from said electronic computing means and storing a misfiring condition.

Claim 7

In an internal combustion engine as claimed in claim 4, said electric energizing means is a relay switch means of a self-holding type to thereby store a misfiring condition.

Claim 8

In an internal combustion engine as claimed in claim 4, said electronic computing means includes a self-holding circuit for storing a misfiring condition.

Claim 9

In an internAl combustion engine having at least one combustion chamber, an exhaust system including an exhaust port opening to said combustion chamber, an exhaust manifold and two exhaust pipes connected to said exhaust manifold, an exhaust gas purifying means disposed in one of said exhaust pipes, and a secondary air supply system including an air cleaner, an air pump for sucking air filtered through said air cleaner and a secondary air supplying pipe with a one-way check valve for supplying a secondary air from said air pump into said exhaust manifold through a nozzle; a protective system for preventing said exhaust gas purifying means from being destroyed by unburned gas emitted from said combustion chamber in the event that a misfire occurs in said combustion chamber comprising: a gas current pulse generator disposed in said exhaust manifold in the vicinity of said exhaust port, said gas current pulse generator having electrodes forming an ion-gap for generating gas current pulse signal when a high temperature burned gas is emitted through said ion-gap from said combustion chamber; an engine speed sensor driven by said engine producing an engine speed pulse signal with a repetition rate proportional to the speed of said engine; an electronic computing means responsive to said gas current pulse signal and said engine speed pulse signal to produce an electric output signal representing the occurence of the misfire when the ratio of the number of said gas current pulse signal to that of said engine speed pulse signal is less than a predetermined value; first bypass valve means disposed in said exhaust pipes for preventing said unburned gas from passing through said exhaust gas purifying means; a first solenoid actuator for actuating said first bypass valve means; a secondary air supply control means for preventing said secondary air from being drawn into said exhaust gas purifying means, said control means comprising a second bypass valve means disposed in said secondary air supplying pipe for feeding back said secondary air into said air pump through a bypass passageway communicating between said secondary air supplying pipe and said air pump and a second solenoid actuating said second bypass valve means; and electric energizing means for energizing said first and second solenoid actuators in response to said output signal from said electronic computing means and storing a misfiring condition.

Claim 10

In an internAl combustion engine having at least one combustion chamber, an exhaust system including an exhaust port opening to said combustion chamber, an exhaust manifold and two exhaust pipes connected to said exhaust manifold, an exhaust gas purifying means disposed in one of said exhaust pipes, and a secondary air supply system including an air cleaner, an air pump for sucking air filtered through said air cleaner and a secondary air supplying pipe with a one-way check valve for supplying a secondary air from said air pump into said exhaust manifold through a nozzle; a protective system for preventing said exhaust gas purifying means from being destroyed by unburned gas emitted from said combustion chamber in the event that a misfire occurs in said combustion chamber comprising: a gas current pulse generator disposed in said exhaust manifold in the vicinity of said exhaust port, said gas current pulse generator having electrodes forming an ion-gap for generating gas current pulse signal when a high temperature burned gas is emitted through said ion-gap from said combustion chamber; an engine speed sensor driven by said engine producing an engine speed pulse signal with a repetition rate proportional to the speed of said engine; an electronic computing means responsive to said gas current pulse signal and said engine speed pulse signal to produce an electric output signal representing the occurence of the misfire when the ratio of the number of said gas current pulse signal to that of said engine speed pulse signal is less than a predetermined value; first bypass valve means disposed in said exhaust pipes for preventing said unburned gas from passing through said exhaust gas purifying means; a first solenoid actuator for actuating said first bypass valve means; a secondary air supply control means for preventing said secondary air from being drawn into said exhaust gas purifying means, said control means comprising a second bypass valve means disposed in said secondary air supplying pipe for feeding back said secondary air into said air pump through a bypass passageway communicating between said secondary air supplying pipe and said air pump and a second solenoid actuating said second bypass valve means; and electric energizing means for energizing said first and second solenoid actuators in response to said output signal from said electronic computing means and storing a misfiring condition.

Claim 11

In an internal combustion engine as claimed in claim 7, said electric energizing means is a relay switch means of a self-holding type to thereby store a misfiring condition.

Claim 12

In an internal combustion engine as claimed in claim 7, said electronic computing means includes a self-holding circuit for storing a misfiring condition.