Claims
- 1. A variable area venturi carburetor having an air and fuel induction passage connected to air at one end and to an engine intake manifold at the opposite end to subject the passage to the changing engine manifold depression for the induction of air and fuel into the engine, a throttle plate rotatably mounted across the passage for controlling flow through the passage, the induction passage containing a venturi providing a change in velocity and pressure level to fluid flow therethrough, a control pressure sensing port opening into the venturi to subject the port at all times to the pressure depression in the venturi, the venturi including a movable wall movable to vary the venturi flow area, vacuum responsive servo means connected to the movable wall for variably moving the wall to vary the venturi area between a minimum area engine idle speed position and a maximum area engine wide open throttle position, first conduit connecting the pressure port to the servo means for communicating the control pressure level in the venturi to the servo means to move the same and thereby move the movable wall to vary the venturi area in response to opening movement of the throttle plate, second conduit means connected at one end to manifold vacuum in the induction passage below the throttle valve at a location to be traversed by the edge of the throttle valve during opening movement of the throttle valve to subject the second conduit means to progressively lower manifold vacuum force levels, means connecting the opposite end of the second conduit means to the first conduit means between the port and servo means, the first conduit means having a larger flow area than the second conduit means to thereby effect the decay of the level of manifold vacuum force in the second conduit means to the level of the control pressure in the first conduit means whereby the control pressure in the control port alone controls the movement of the servo means during normal operation of the engine at normal temperature levels and thereby alone controls variance of the venturi area during this time, and means to progressively change control of the servo means from the control pressure to the manifold vacuum as the temperature level changes from the normal level to the coldest extreme below the normal level, the latter means comprising temperature responsive valve means movable variably into the first conduit means in response to the attainment of below normal engine operating temperature levels to progressively restrict the communication of control pressure from the port to the servo means as a function of decreasing temperature and thereby progressively switch control of the movement of the servo means and venturi wall from the control pressure in the venturi to the manifold vacuum in the second conduit means, and means movable in response to temperature changes below the normal engine operating temperature level connected to and moving the temperature responsive valve means.
- 2. An enrichment device as in claim 1, the temperature responsive means including a needle valve, movable into and out of the conduit means to block and unblock bleed of manifold vacuum by the venturi-like vacuum.
- 3. An enrichment device as in claim 2, the temperature responsive means including a temperature sensitive spring movable in response to temperature changes and connected to the needle valve.
- 4. An enrichment device as in claim 2, including means to adjust the needle valve to vary its characteristics of operation.
Parent Case Info
This is a continuation of application Ser. No. 430,956, filed Jan. 4, 1974, now abandoned.
US Referenced Citations (9)
Continuations (1)
|
Number |
Date |
Country |
Parent |
430956 |
Jan 1974 |
|