Exhaust gas recirculator

An exhaust gas recirculator comprising:

• a pressure control valve for controlling the amount of recirculative exhaust gas in two stages, said valve being positioned in a recirculation passage coupling an exhaust system and an intake system of an internal combustion engine, said valve comprising:
• means defining a first pressure control chamber therein,
• means defining a second pressure control chamber therein,
• means for fluidly connecting said second pressure control chamber to a first vacuum port, in the intake system of the internal combustion engine, slightly above the fully closed position of a throttle valve of a carburetor, and
• means for fluidly connecting said first pressure control chamber to a second vacuum port in the intake system slightly above said first vacuum port so that the vacuum at each of said ports which is communicated to said chambers is controlled by the degree of opening of the throttle valve.

An exhaust gas recirculator comprising:

• a pressure control valve for controlling the amount of recirculative exhaust gas in two stages, said valve being positioned in a recirculation passage coupling an exhaust system and an intake system of an internal combustion engine, said valve comprising means defining a first pressure control chamber and means defining a second pressure control chamber,
• a vacuum circuit, including a vacuum change-over valve, for fluidly communicating said pressure control valve, including said first pressure control chamber and said second pressure control chamber, to a first vacuum port, in the intake system of the internal combustion engine, slightly above the fully closed position of a throttle valve of a carburetor, and to a second vacuum port, in the intake system of the internal combustion engine, slightly above said first vacuum port,
• said first pressure control chamber being fluidly communicated with vacuum at the first vacuum port when the vacuum of the engine is high,
• said second pressure control chamber being fluidly communicated with vacuum at the second vacuum port when the vacuum of the engine is low so that the vacuum at each of said ports is controlled by the degree of opening of the throttle valve.

In an internal combustion engine having an intake system, an exhaust system and a recirculation passage through which exhaust gas from the exhaust system may be recirculated to the intake system, the improvement comprising:

• a control valve in said passage for controlling the amount of recirculation exhaust gas in two stages, said valve comprising:
• a valve seat,
• a valve body for seating on said seat to thereby close said valve and block said passage and simultaneously block recirculation of exhaust gas,
• means defining a first pressure control chamber therein,
• means defining a second pressure control chamber therein,
• means connecting said valve body to the means defining the first pressure control chamber and the means defining the second pressure control chamber,
• means for fluidly communicating said first pressure control chamber and said intake system, and
• means for fluidly communicating said second pressure control chamber and said intake system whereby when vacuum is selectively introduced into said chambers from the intake system, the movement of the valve body from the valve seat is controlled in two stages and the spacing of the valve body from the valve seat is changed in two stages so that the flow rate of recirculated exhaust gas can be regulated in two stages.

In an internal combustion engine having an intake system including a carburetor having a throttle valve, an exhaust system and a recirculation passage through which exhaust gas from the exhaust system may be recirculated to the intake system, the improvement comprising:

• means defining a first vacuum port in said intake system adjacent to but slightly above the fully closed position of the throttle valve,
• means defining a second vacuum port in said intake system slightly above said first vacuum port,
• a control valve in said passage for controlling the amount of recirculative exhaust gas in two stages, said valve comprising:
• a valve seat,
• a valve body for seating on said seat to thereby close said valve and block said passage and simultaneously block recirculation of exhaust gas,
• a first diaphragm,
• a second diaphragm spaced from said first diaphragm, said second diaphragm being of larger corss-sectional area than that of said first diaphragm,
• means, including said first diaphragm, defining a first pressure control chamber therein,
• means, including said first diaphragm and said second diaphragm, defining a second pressure control chamber therein,
• means connecting the valve body to the first diaphragm and the second diaphragm,
• means for fluidly communicating said first pressure control chamber to said second vacuum port, and
• means for fluidly communicating said second pressure control chamber to said first vacuum port whereby when vacuum is introduced into said first and second chambers from said second and first vacuum ports respectively, the movement of the valve body from the valve seat is controlled in two stages and the spacing of the valve body from the valve seat is changed in two stages so that the flow rate of recirculated exhaust gas can be regulated in two stages.

In an internal combustion engine having an intake system including a carburetor having a throttle valve, an exhaust system and a recirculation passage through which exhaust gas from the exhaust system may be recirculated to the intake system, the improvement comprising:

• means defining a vacuum port in said intake system adjacent to but slightly above the fully closed position of the throttle valve,
• a control valve in said passage for controlling the amount of recirculative exhaust gas in two stages, said valve comprising:
• means defining a first pressure control chamber therein, and
• means defining a second pressure control chamber therein,
• a vacuum circuit, including a vacuum change-over valve, for fluidly communicating said vacuum port with said first pressure control chamber and said second pressure control chamber so that vacuum at the port is communicated to said first pressure control chamber when the vacuum of the engine is high and the vacuum at the port is communicated to both said first pressure control chamber and said second pressure control chamber when the vacuum is low whereby the flow rate of recirculated exhaust gas is controlled dependent upon the load on the engine.

In an internal combustion engine having an intake system including a carburetor having a throttle valve, an exhaust system and a recirculation passage through which the exhaust gas from the exhaust system may be recirculated to the intake system, the improvement comprising:

• means defining a first vacuum port in the intake system adjacent to but slightly above the fully closed position of the throttle valve,
• means defining a second vacuum port in the intake system slightly above the first vacuum port,
• a control valve in said passage for controlling the amount of recirculative exhaust gas into two stages, said control valve comprising:
• means defining a first pressure control chamber therein, and
• means defining a second pressure control chamber therein,
• a vacuum circuit, including a vacuum change-over valve, for fluidly communicating said first vacuum port and said first pressure control chambers and for fluidly communicating said second vacuum port to said second pressure control chamber,
• said first pressure control chamber being fluidly communicated with vacuum at the first vacuum port when the vacuum of the engine is high, and
• said second pressure control chamber being fluidly communicated with vacuum at the second vacuum port when the vacuum of the engine is low so that the vacuum at each of said ports is controlled by the degree of opening of the throttle valve.