Air-pollution preventive system for motor vehicles

Claim 2

An air-pollution preventive system for a motor vehicle having an internal combustion engine, adapted to reduce the concentration of nitrogen oxides in the exhaust gases emitted from the engine to the open air, comprising: 1. an exhaust recirculation control valve assembly having a chamber communicating on one side with an exhaust manifold of said engine and on the other with an intake manifold of said engine; 2. first means responsive to the intake manifold vacuum for controlling said control valve assembly, which means includes a vacuum switch and a diaphragm device having a vacuum chamber communicating with the intake manifold, an atmospheric chamber vented to the atmosphere, a diaphragm member separating said vacuum and atmospheric chambers with each other, said diaphragm member being connected with said vacuum switch, and a compression spring forcing said diaphragm member toward a position in which the vacuum switch is open, the loading of said spring being determined to overpower the intake manifold vacuum higher than a predetermined level, said vacuum switch being closed when the intake manifold vacuum is below said predetermined level; and 3. second means responsive to the engine speed for controlling said control valve assembly, which means includes an engine speed switch and a solenoid device having a solenoid coil and moving core, said moving core being connected with said engine speed switch and normally held in a position to open the same, and a pulse counter connected at its outer terminal with the ignition distributor for detecting the number of pulses within a predetermined range of the engine speed whereby said moving core protrudes into a position to close said engine speed switch; said control valve assembly being open to permit the exhaust gases to recirculate into the intake manifold only when said vacuum and engine speed switches are closed.

Claim 3

first means responsive to the intake manifold vacuum for controlling said control valve assembly, which means includes a vacuum switch and a diaphragm device having a vacuum chamber communicating with the intake manifold, an atmospheric chamber vented to the atmosphere, a diaphragm member separating said vacuum and atmospheric chambers with each other, said diaphragm member being connected with said vacuum switch, and a compression spring forcing said diaphragm member toward a position in which the vacuum switch is open, the loading of said spring being determined to overpower the intake manifold vacuum higher than a predetermined level, said vacuum switch being closed when the intake manifold vacuum is below said predetermined level; and

Claim 4

first means responsive to the intake manifold vacuum for controlling said control valve assembly, which means includes a vacuum switch and a diaphragm device having a vacuum chamber communicating with the intake manifold, an atmospheric chamber vented to the atmosphere, a diaphragm member separating said vacuum and atmospheric chambers with each other, said diaphragm member being connected with said vacuum switch, and a compression spring forcing said diaphragm member toward a position in which the vacuum switch is open, the loading of said spring being determined to overpower the intake manifold vacuum higher than a predetermined level, said vacuum switch being closed when the intake manifold vacuum is below said predetermined level; and

Claim 5

A system according to claim 1, wherein said control valve assembly includes a casing communicating on one side with the exhaust manifold through an exhaust recirculation conduit and on the other with the intake manifold through an exhaust recirculation nozzle, a valve head which is positioned relative to a valve seat formed in said casing, a compression spring accommodated in said casing to force said valve heaD against said valve seat to isolate said conduit from said nozzle, a moving core connected with said valve head, and a solenoid coil associated with the last named moving core and connected with a power source and with said vacuum and engine speed switches, said moving core being moved away from said valve seat against the action of the last named spring to cause said valve head to be unseated when the last named solenoid coil is excited with said vacuum and engine speed switches closed concurrently, whereby said conduit is permitted to communicate with said nozzle.

Claim 6

A system according to claim 1, wherein said control valve assembly includes a spool valve device and a solenoid valve device, said spool valve device including a casing communicating on one side with the exhaust manifold through an exhaust recirculation conduit and on the other with the intake manifold through an exhaust recirculation nozzle, a spool valve axially movably mounted in said casing and having a land at one end, and a compression spring mounted in said casing to force said spool valve toward a position in which said land isolates said conduit from said nozzle, the loading of said compression spring being determined to yield to the intake manifold vacuum lowered to said predetermined level, said solenoid valve device including a solenoid valve casing communicating with said casing of the spool valve device, said solenoid valve casing further communicating on one side with the intake manifold through a vacuum conduit and on the other with the atmosphere, a moving core axially movably mounted in said solenoid valve casing and acting at the same time as a valve member, said moving core being normally forced into a position to isolate said vacuum conduit from said casing of said spool valve device by a spring action, and a solenoid coil associated with said moving core and connected with a power source and with said vacuum and engine speed switches, said moving core being moved to a position to permit said vacuum conduit to communicate with said casing of said spool valve device to cause said spool valve to be moved against the action of said spring in said spool valve device to a position in which said land is moved to a position in which sad exhaust recirculation conduit is permitted to communicate with said nozzle when said solenoid coil of said solenoid valve device is excited with said vacuum and engine speed switches closed concurrently.

Claim 7

second means responsive to the engine speed for controlling said control valve assembly, which means includes an engine speed switch and a solenoid device having a solenoid coil and moving core, said moving core being connected with said engine speed switch and normally held in a position to open the same, and a pulse counter connected at its outer terminal with the ignition distributor for detecting the number of pulses within a predetermined range of the engine speed whereby said moving core protrudes into a position to close said engine speed switch; said control valve assembly being open to permit the exhaust gases to recirculate into the intake manifold only when said vacuum and engine speed switches are closed.

Claim 8

second means responsive to the engine speed for controlling said control valve assembly, which means includes an engine speed switch and a solenoid device having a solenoid coil and moving core, said moving core being connected with said engine speed switch and normally held in a position to open the same, and a pulse counter connected at its outer terminal with the ignition distributor for detecting the number of pulses within a predetermined range of the engine speed whereby said moving core protrudes into a position to close said engine speed switch; said control valve assembly being open to permit the exhaust gases to recirculate into the intake manifold only when said vacuum and engine speed switches are closed.

Claim 9

A system according to claim 1, wherein said control valve assembly includes a diaphragm valve device and a solenoid valve device, said diaphragm valve device including a vacuum chamber, a diaphragm member forming part of the structure of said vacuum chamber, a port communicating on one side with the exhaust manifold through an exhaust recirculation conduit and on the other with the intake manifold through an exhaust recirculation nozzle, a valve head connected with said diaphragm member and directed toward said port, and a compression spring mounted in said vacuum chamber to force said diaphragm member toward a position in which said valve head closes said port, the loading of said compression spring being determined to yield to the intake manifold vacuum lowered to said predetermined level, said solenoid valve device including a solenoid valve casing communicating with said casing of the diaphragm valve device, said solenoid valve casing further communicating on one side with the intake manifold through a vacuum conduit and on the other with the atmosphere, a moving core axially movably mounted in said solenoid valve casing and acting at the same time as a valve member, said moving core being normally forced into a position to isolate said vacuum conduit from said casing of said diaphragm valve device by a spring action, and a solenoid coil associated with said moving core and connected with a power source and with said vacuum and engine speed switches, said moving core being moved to a position to permit said vacuum conduit to communicate with sAid casing of said spool valve device to cause said diaphragm member to be moved against the action of said spring in said diaphragm valve device to a position in which said valve head is moved to a position to open said port whereby said exhaust recirculation conduit is permitted to communicate with said nozzle when said solenoid coil of said solenoid valve device is excited with said vacuum and engine speed switches closed concurrently.