Exhaust gas purifying system for use in internal combustion engine

Claim 2

An exhaust gas purifying system for use in an automobile internal combustion engine comprising a spark plug ignition system including at least one spark plug, a power source and an ignition switch, for effecting a combustion of fuel-air mixture that has been supplied to a combustion chamber of the engine through a carburetor having a throttle valve and disposed on an intake passage of said engine, the exhaust gas purifying system comprising an air supply means disposed on the connection between a suitable air source and the intake passage for supplying primary air to the intake passage, means for detecting the deceleration and stoppage of the engine and for opening said air supply means when the engine is decelerated and stopped, said detecting means including a first switch and a second switch parallely diposed with respect to said first switch, both said first and second switches being connected in series between said ignition switch and said air supply means for operating the latter in response to the engine operating conditions, said first switch being adapted to be opened during the substantial closure of said throttle valve and said second switch being adapted to be closed only when the engine speed is smaller than a predetermined value, wherein, when the engine is decelerated with the engine speed exceeding over said predetermined value during the substantial closure of said throttle valve, both said first and second switches are opened to permit the air supply means to supply the primary air to the intake passage and, even though said ignition switch is turned off, the supply of the primary air to the intake passage can be effected.

Claim 3

An exhaust gas purifying system for use in an automobile internal combustion engine comprising a spark plug ignition system including at least one spark plug, a power source and an ignition switch, for effecting a combustion of fuel-air mixture that has been supplied to a combustion chamber of the engine through a carburetor having a throttle valve and disposed on an intake passage of said engine, the exhaust gas purifying system which comprises a diaphragm valve having a diaphragm member and a pair of working chambers partitioned by said diaphragm member, a first one of said working chamber of said diaphragm valve being connected to the atmosphere through a suitable passage and the other second working chamber thereof being connected with the intake passage of the engine, an air flow control valve disposed on the connection between a suitable air source and the intake passage and operatively associated with said diaphragm valve, a solenoid valve disposed on said passage connecting between the first working chamber of the diaphragm valve and the atmosphere, and means including first and second switches parallely disposed with respect to each other and series disposed between said ignition switch and said solenoid valve for operating said solenoid valve, said first switch adapted to be opened during the idling and deceleration of the engine and said second switch adapted to be closed only when the engine speed is smaller than a predetermined value, said solenoid valve being closed in response to the closure of either of said first and second switches to close said passage connecting between the first working chamber of the diaphragm valve and the atmosphere, whereby no primary air can be additionally supplied into the intake passage through said air flow control valve, in which condition said air control valve being maintained by said diaphragm valve in position to cut off the connection between the air source and the intake passage.

Claim 4

An exhaust gas purifying system for use in an automobile internal combustion engine comprising a spark plug ignition system including at least one spark plug, a power source and an ignition switch, for effecting a combustion of fuel-air mixture that has been supplied to a combustion chamber of the engine through a carburetor having a throttle valve and disposed on an intake passage of said engine, the exhaust gas purifying system which comprises a diaphragm valve having a diaphragm member and a pair of working chambers partitioned by said diaphragm member, a first one of said working chamber of said diaphragm valve being connected to the atmosphere through a suitable passage and the other second working chamber thereof being connected with the intake passage of the engine, an air flow control valve disposed on the connection between a suitable air source and the intake passage and operatively associated with said diaphragm valve, a solenoid valve disposed on said passage connecting between the first working chamber of the diaphragm valve and the atmosphere, and means including first and second switches parallely disposed with respect to each other and series disposed between said ignition switch and said solenoid valve for operating said solenoid valve, said first switch adapted to be opened during the idling and deceleration of the engine and said second switch adapted to be closed only when the engine speed is smaller than a predetermined value, said solenoid valve being closed in response to the closure of either of said first and second switches to close said passage connecting between the first working chamber of the diaphragm valve and the atmosphere, whereby no primary air can be additionally supplied into the intake passage through said air flow control valve, in which condition said air control valve being maintained by said diaphragm valve in position to cut off the connection between the air source and the intake passage.

Claim 5

An exhaust gas purifying system as claimed in claim 2, wherein said air flow control valve is normally maintained in position to cut off the connection between the air source and the intake passage, but to open said connection only when said solenoid valve is in position to permit the communication between the first working chamber of the diaphragm valve and the atmosphere.

Claim 6

An exhaust gas purifying system as claimed in claim 2, wherein said predetermined value at which said second switch is closed is 1,500 r.p.m.

Claim 7

An exhaust gas purifying system as claimed in claim 2, wherein said first switch is operatively associated with the throttle valve in such a way as to open upon the substantial closure of said throttle valve and to close upon opening of said throttle valve.

Claim 8

An exhaust gas purifying system for use in an automobile internal combustion engine comprising a spark plug ignition system including at least one spark plug, a power source and an ignition switch, for effecting a combustion of fuel-air mixture that has been supplied to a combustion chamber of the engine through a carburetor having a throttle valve and disposed on an intake passage of said engine, the exhaust gas purifying system which comprises a first diaphragm valve having a diaphragm member and a pair of working chambers partitioned by said diaphragm member, a first one of said working chamber of said first diaphragm valve being connected to the atmosphere through a suitable passage and the other second working chamber thereof being connected with the intake passage of the engine, a first air flow control valve disposed on the connection between a suitable air source and the intake passage and operatively associated with said first diaphragm valve, a first solenoid valve disposed on said passage connecting between the first working chamber of the first diaphragm valve and the atmosphere, means including parallely disposed first and second switches which are disposed in series between said ignition switch and said first solenoid valve, a relay assembly having a relay coil inserted between the parallely disposed first and second switches and said first solenoid valve and a relay switch, said first switch adapted to be opened during the idling deceleration of the engine and said second switch adapted to be closed only when the engine speed is smaller than a first predetermined value, said solenoid valve being closed in response to the closure of either of said first and second switches to close said passage connecting between the first working chamber of said first diaphragm valve and the atmosphere, a second diaphragm valve having a pair of first and second working chambers partitioned by a diaphragm member, one of said working chambers being connected with the intake passage through a suitable passage, a second air flow control valve having a pair of first and scond working chambers, a first one of said working chambers thereof being connected with an exhaust passage of the engine through a check valve, capable of permitting the flow of air from said first working chamber to said exhaust passage, and the other second working chamber of said second air flow control valve being connected with the atmosphere through an air jacket formed around an exhaust gas purifying device disposed on said exhaust passage for effecting a recombustion of unburned noxious compounds present in the exhaust gas, a second solenoid valve disposed on the connection between the intake passage and the first working chamber of said second diaphragm valve, and said means further including a third switch adapted to be closed, when the engine speed is smaller than a second predetermined value, for bringing said second solenoid valve in position to open said connection between said intake passage and the first working chamber of said second diaphragm valve, whereby, during the idling, the acceleration and the normal operating condition of the engine while the ignition switch is switched on, only secondary air can be supplied to the exhaust passage through the second air flow control valve to aid the recombustion of the unburned compounds within the exhaust gas purifying device; during the high speed operation while the ignition swItch is switched on, only the secondary air can be supplied to the air jacket to cool the afterburner; during the deceleration of the engine, only primary air can be supplied into the intake passage to prevent abnormal combustion from occurring in the exhaust passage while the secondary air can be supplied to the air jacket through said second air flow control valve; and, so long as the ignition switch is switched off, the flow of the primary air from the air source to the intake passage through the first air flow control valve can be permitted to prevent the occurrence of abnormal combustion in the exhaust passage which may take place by the effect of a relatively high temperature existing at and around the exhaust passage.

Claim 9

An exhaust gas purifying system for use in an automobile internal combustion engine comprising a spark plug ignition system including at least one spark plug, a power source and an ignition switch, for effecting a combustion of fuel-air mixture that has been supplied to a combustion chamber of the engine through a carburetor having a throttle valve and disposed on an intake passage of said engine, the exhaust gas purifying system which comprises a first diaphragm valve having a diaphragm member and a pair of working chambers partitioned by said diaphragm member, a first one of said working chamber of said first diaphragm valve being connected to the atmosphere through a suitable passage and the other second working chamber thereof being connected with the intake passage of the engine, a first air flow control valve disposed on the connection between a suitable air source and the intake passage and operatively associated with said first diaphragm valve, a first solenoid valve disposed on said passage connecting between the first working chamber of the first diaphragm valve and the atmosphere, means including parallely disposed first and second switches which are disposed in series between said ignition switch and said first solenoid valve, a relay assembly having a relay coil inserted between the parallely disposed first and second switches and said first solenoid valve and a relay switch, said first switch adapted to be opened during the idling deceleration of the engine and said second switch adapted to be closed only when the engine speed is smaller than a first predetermined value, said solenoid valve being closed in response to the closure of either of said first and second switches to close said passage connecting between the first working chamber of said first diaphragm valve and the atmosphere, a second diaphragm valve having a pair of first and second working chambers partitioned by a diaphragm member, one of said working chambers being connected with the intake passage through a suitable passage, a second air flow control valve having a pair of first and scond working chambers, a first one of said working chambers thereof being connected with an exhaust passage of the engine through a check valve, capable of permitting the flow of air from said first working chamber to said exhaust passage, and the other second working chamber of said second air flow control valve being connected with the atmosphere through an air jacket formed around an exhaust gas purifying device disposed on said exhaust passage for effecting a recombustion of unburned noxious compounds present in the exhaust gas, a second solenoid valve disposed on the connection between the intake passage and the first working chamber of said second diaphragm valve, and said means further including a third switch adapted to be closed, when the engine speed is smaller than a second predetermined value, for bringing said second solenoid valve in position to open said connection between said intake passage and the first working chamber of said second diaphragm valve, whereby, during the idling, the acceleration and the normal operating condition of the engine while the ignition switch is switched on, only secondary air can be supplied to the exhaust passage through the second air flow control valve to aid the recombustion of the unburned compounds within the exhaust gas purifying device; during the high speed operation while the ignition swItch is switched on, only the secondary air can be supplied to the air jacket to cool the afterburner; during the deceleration of the engine, only primary air can be supplied into the intake passage to prevent abnormal combustion from occurring in the exhaust passage while the secondary air can be supplied to the air jacket through said second air flow control valve; and, so long as the ignition switch is switched off, the flow of the primary air from the air source to the intake passage through the first air flow control valve can be permitted to prevent the occurrence of abnormal combustion in the exhaust passage which may take place by the effect of a relatively high temperature existing at and around the exhaust passage.

Claim 10

An exhaust gas purifying system as claimed in claim 6, wherein said second predetermined value is 5,000 r.p.m.