Secondary air regulating system for automotive internal combustion engine

Claim 2

In an automotive internal combustion engine having an exhaust port located downstream of an exhaust valve and an exhaust manifold communicating with said exhaust port, a system for regulating the amount of secondary air to be fed to said exhaust manifold downstream of said exhaust port for oxidizing unburned exhaust gases from said engine comprising, in combination, a pneumatic pump driven by said engine for supplying secondary air to said exhaust manifold, a main passageway communicating with said pneumatic pump, a check valve disposed in said main passageway to prevent the back-flow of the exhaust gases to said pneumatic pump, an air gallery communicating with said main passageway downstream of said check valve, a secondary air inlet pipe communicating with said air gallery and opening into said exhaust manifold and being exposed to the pressure of the exhaust gases in said exhaust manifold, and a control valve assembly located in said main passageway downstream of said pneumatic pump, said control valve assembly including means defining an inlet communicating with said main passageway up-stream of said check valve and means defining an outlet, a valve plate disposed adjacent said inlet for opening and closing said inlet, and biasing means operatively connected to said valve plate, said biasing means being responsive to at least one of the pressures prevailing in said air gallery and the pressures prevailing in said exhaust manifold to bias said valve plate toward a direction to close said inlet, whEreby said valve plate is movable to open and close said inlet thereby to vary the level of secondary air pressure in said main passageway in dependence on the pressure difference between said secondary air pressure and said at least one of the pressures prevailing in said air gallery and the pressures prevailing in said exhaust manifold.

Claim 3

In an automotive internal combustion engine having an exhaust port located downstream of an exhaust valve and an exhaust manifold communicating with said exhaust port, a system for regulating the amount of secondary air to be fed to said exhaust manifold downstream of said exhaust port for oxidizing unburned exhaust gases from said engine comprising, in combination, a pneumatic pump driven by said engine for supplying secondary air to said exhaust manifold, a main passageway communicating with said pneumatic pump, a check valve disposed in said main passageway to prevent the back-flow of the exhaust gases to said pneumatic pump, an air gallery communicating with said main passageway downstream of said check valve, a secondary air inlet pipe communicating with said air gallery and opening into said exhaust manifold, and being exposed to the pressure of the exhaust gases in said exhaust manifold, and a control valve assembly located in said main passageway downstream of said pneumatic pump, said control valve assembly including means defining an inlet communicating with said main passageway and means defining an outlet, a valve plate disposed adjacent said inlet for opening and closing said inlet, first biasing means biasing said valve plate in a direction to close said inlet, and second biasing means in communication with said air gallery and being responsive to at least one of the pressures prevailing in said air gallery and the pressures prevailing in said exhaust manifold to bias said valve plate in a direction to close said inlet, whereby said valve plate is movable to open and close said inlet thereby to vary the level of secondary air pressure in said main passageway in dependence on the pressure difference between said secondary air pressure and the pressures of said first biasing means and said second biasing means.

Claim 4

In an automotive internal combustion engine having an exhaust port located downstream of an exhaust valve and an exhaust manifold communicating with said exhaust port, a system for regulating the amount of secondary air to be fed to said exhaust manifold downstream of said exhaust port for oxidizing unburned exhaust gases from said engine comprising, in combination, a pneumatic pump driven by said engine for supplying secondary air to said exhaust manifold, a main passageway communicating with said pneumatic pump, a check valve disposed in said main passageway to prevent the back-flow of the exhaust gases to said pneumatic pump, an air gallery communicating with said main passageway downstream of said check valve, a secondary air inlet pipe communicating with said air gallery and opening into said exhaust manifold, and being exposed to the pressure of the exhaust gases in said exhaust manifold, and a control valve assembly located in said main passageway downstream of said pneumatic pump, said control valve assembly including means defining an inlet communicating with said main passageway and means defining an outlet, a valve plate disposed adjacent said inlet for opening and closing said inlet, first biasing means biasing said valve plate in a direction to close said inlet, and second biasing means in communication with said air gallery and being responsive to at least one of the pressures prevailing in said air gallery and the pressures prevailing in said exhaust manifold to bias said valve plate in a direction to close said inlet, whereby said valve plate is movable to open and close said inlet thereby to vary the level of secondary air pressure in said main passageway in dependence on the pressure difference between said secondary air pressure and the pressures of said first biasing means and said second biasing means.

Claim 5

A system according to claim 2, wherein said first biasing means includes a compression spring.

Claim 6

A system according to claim 2, wherein said second biasing means includes a diaphragm member which is connected to said valve plate.

Claim 7

In an automotive internal combustion engine having an exhaust port located downstream of an exhaust valve and an exhaust manifold communicating with said exhaust port, a system for regulating the amount of secondary air to be fed to said exhaust manifold downstream of said exhaust port for oxidizing unburned exhaust gases from said engine comprising, in combination, a pneumatic pump driven by said engine for supplying secondary air to said exhaust manifold, a main passageway communicating with said pneumatic pump, a check valve disposed in said main passageway to prevent the back-flow of the exhaust gases to said pneumatic pump, an air gallery communicating with said main passageway downstream of said check valve, a secondary air inlet pipe communicating with said air gallery and opening into said exhaust manifold and being exposed to the pressure of the exhaust gases in said exhaust manifold, and a control valve assembly located in said main passageway downstream of said pneumatic pump, said control valve assembly including a valve casing, first and second chambers defined in said valve casing, said first chamber having means defining an inlet communicating with said main passageway downstream of said pneumatic pump and means defining an outlet opening to the atmosphere, a valve plate slidably disposed in said first chamber to open and close said inlet, a first biasing means disposed in said first chamber and biasing said valve plate in a direction to close said inlet, a second biasing means disposed in said second chamber and cooperating with said first biasing means to bias said valve plate, and a branch passageway connecting said second chamber to said air gallery and said exhaust manifold, said second biasing means being responsive to the pressure prevailing in said air gallery to vary the biasing force thereof in accordance with at least one of said pressures in said gallery and said exhaust manifold, whereby the amount of leakage of secondary air from said main passageway to the atmosphere varies in accordance with pressure difference between said secondary air pressure and the pressure of said exhaust gases.

Claim 8

In an automotive internal combustion engine having an exhaust port located downstream of an exhaust valve and an exhaust manifold communicating with said exhaust port, a system for regulating the amount of secondary air to be fed to said exhaust manifold downstream of said exhaust port for oxidizing unburned exhaust gases from said engine comprising, in combination, a pneumatic pump driven by said engine for supplying secondary air to said exhaust manifold, a main passageway communicating with said pneumatic pump, a check valve disposed in said main passageway to prevent the back-flow of the exhaust gases to said pneumatic pump, an air gallery communicating with said main passageway downstream of said check valve, a secondary air inlet pipe communicating with said air gallery and opening into said exhaust manifold and being exposed to the pressure of the exhaust gases in said exhaust manifold, and a control valve assembly located in said main passageway downstream of said pneumatic pump, said control valve assembly including a valve casing, first and second chambers defined in said valve casing, said first chamber having means defining an inlet communicating with said main passageway downstream of said pneumatic pump and means defining an outlet opening to the atmosphere, a valve plate slidably disposed in said first chamber to open and close said inlet, a first biasing means disposed in said first chamber and biasing said valve plate in a direction to close said inlet, a second biasing means disposed in said second chamber and cooperating with said first biasing means to bias said valve plate, and a branch passageway connecting said second chamber to said air gallery and said exhaust manifold, said second biasing means being responsive to the pressure prevailing in said air gallery to vary the biasing force thereof in accordance with at least one of said pressures in said gallery and said exhaust manifold, whereby the amount of leakage of secondary air from said main passageway to the atmosphere varies in accordance with pressure difference between said secondary air pressure and the pressure of said exhaust gases.