Abstract: In an exhaust gas cleaning system for an internal combustion engine in which additional air is injected from outside into an engine exhaust manifold by an on-off-duty solenoid valve under control of a microcomputer operating on the partial oxygen pressure in the exhaust gas as detected by an oxygen sensing element, the engine r.p.m. and the exhaust gas temperature, a vacuum control valve adapted to add vacuum signals responsive to variations in the intake manifold vacuum of the engine and throttle opening to the output vacuum signals of the solenoid valve commanding the air injection.

Abstract: A pilot stage for use in pilot pressure control applications includes a magnetic torque motor having an output torque in response to an input current, a flapper operated by the magnetic torque motor and responsive to the output torque, the magnetic torque motor being arranged to apply a resultant spring rate to the flapper, and first and second nozzles responsive to the output torque applied to the flapper for providing a differential output pressure proportional to input current, the first and second nozzles having a size sufficiently large to swamp out the resultant spring rate applied to the flapper so that the first and second nozzles apply a feedback force to the flapper sufficient by itself to substantially balance motor torque.

Abstract: A fluid control system for cleaning exhaust gases of an internal combustion engine by injecting additional air into the exhaust manifold of the downstream of the combustion chamber of the engine according to the engine operating conditions. This system includes a vacuum control valve which supplies vacuum on-off signals to a flow control valve device which meters injecting of additional air.

Abstract: A pneumatic converter comprising a bellows having in its interior a coupling plate connecting the two ends of the bellows together at a position offset from the center axis of the bellows.

Abstract: A pneumatic device is arranged for reducing positive feedback and includes a housing having a diaphragm defining a control chamber, the control chamber being connected to an input and having a pressure therein dependent upon an input pressure, the control chamber having a nozzle therein and operatively associated with the diaphragm so that the position of the diaphragm with respect to the nozzle controls the pressure within the control chamber, the nozzle being sloped for substantially reducing positive feedback resulting from bleeding of the pressure from the nozzle into the control chamber and an output connected to the control chamber for providing an output pressure.

Abstract: A valve (10) is interconnected in a flow line to control the downstream pressure by means of a relatively low pressure control device such as a block and bleed valve coupled to a control port (28). An activating piston (54) is moveable within a piston chamber (32) for activating a ball valve (44) to interconnect an outlet port (22) with an inlet port (20). In a manual reset mode, a pressurized fluid at a reset port (26) enters a regulator chamber (38). From the regulator chamber (38), the fluid flows through a passage between an annulus (42) and an extension tube (62) into the piston chamber (32) and acts against the activating piston (54). As fluid enters the piston chamber (32), the pressure acting against the activating piston (54) increases and moves the piston upward to activate the ball valve (44).

Abstract: An electro-pneumatic current-to-position transducer includes an electric motor having a permanent magnet for a stator and spring restrained coil pivotally suspended about the magnet for a rotor. An input current to the coil induces a mechanical rotation of the coil about the magnet which is proportional to the applied current. Fastened to the coil for rotary movement therewith is a flapper positioned to cover the nozzle of a pneumatic circuit. As current is applied to the coil, the flapper moves toward the nozzle thereby changing the back pressure in the pneumatic circuit. This change in pressure is amplified, then sensed by appropriate pressure-responsive devices and subsequently fed back to a control lever on which the nozzle is mounted, thereby repositioning the nozzle so as to maintain an essentially constant separation between the flapper and the nozzle.

Abstract: A control device having a housing provided with a main lever pivotally mounted thereto by a pivot structure and being operatively associated with a flapper to move the same relative to a leakport in relation to pivotal movement of the main lever. The device has a feedback diaphragm operatively associated with a feedback lever that is pivotally mounted to the housing and is operatively associated with the main lever to cause pivoting thereof upon pivoting movement of the feedback lever by the feedback diaphragm. The device has means for selectively changing the device to be either direct acting or reverse acting by changing the position of the feedback lever and the flapper and without changing the position of the feedback diaphragm and the leakport.

Abstract: A dual thermostat apparatus includes two thermostats which generate fluid control signals proportional to room air temperature. The thermostats are matched leakport pressure sensors having a signal orifice and a bimetal lid element to generate back pressure signals linearly related to temperature. The bimetal elements have adjustment cams to set the reference position with respect to the orifice. The cams are connected to a common shaft and dial to provide simultaneous and opposite readjustment with respect to the reference pressures. The signals are applied to separate signal chambers of the duplex relay, with a pressure regulator connected to the heat signal chamber to limit the operative pressure level of the heating signal to a selected maximum switchover pressure. The duplex relay controls a pressure supply valve for supplying a proportional pressure signal to a common output line to pneumatic operators of a heating valve and a cooling valve.

Abstract: The present invention relates to a current controlled pressure regulating apparatus for operating pneumatically operated elements such as valves in process control systems and the like. The apparatus is designed to provide for direct mechanical control of the pressure regulating apparatus in response to changes in current flow in a two wire current controller.

Abstract: Fluid temperature control system for providing a supply fluid at a select temperature by warming or cooling a first fluid with a controlled flow of a second fluid. The control of the second fluid flow is achieved by a modulation valve adjustable in response to the pressure of a supply of servo fluid which is itself adjusted in response to the temperature of the supply fluid. The adjustment of the servo fluid pressure by the control system is such that the change in servo fluid pressure from a steady state condition is initially great, diminishing with time to a lesser, steady state value, thereby enhancing the transient response of the control system.

Abstract: A vacuum regulator valve (10) is disclosed comprising a force-balance modulator valve subassembly (114, 118, 119, 122, 124, 126) mounted to a housing (12, 30) having inlet (14) and outlet (16) fluid ports. A vent insert (114) is adjustably biased through a biasing spring (166) by a rotary cam arrangement which includes a spring (64) biased rotary input member (48) rotatably mounted on a housing tubular projection (40). A ring-shaped drive member (144) is rotatable with input member (48) and supports a cup-shaped cam member (154). As projections (152) on the reaction member (144) rotate relative to cam surfaces (160), the cam follower is moved linealy relative to the vent insert. Locking tabs (50, 146, 148, 150) and alignment grooves (46, 80, 96, 98) enable the cam arrangement to be assembled in a predetermined angular position and locked to the housing without fasteners. An externally accessible adjustment member (162) enables valve calibration after final assembly.

Abstract: A fluid pressure and electrical signal controller for providing a predetermined regulated vacuum signal from a variable source in response to changes in position of a rotatable input shaft when attached thereto and an electrical signal at a predetermined position of the input shaft. A pressure force balance type vacuum modulator valve is preloaded and biased by a spring connected to a cam follower which tracks a rotary cam turned by the input shaft. The modulator valve is slidably attached to the controller body for adjusting the preload length of the spring and a rotatable adjustment ring engages the valve and is threadedly received on the controller body for effecting sliding adjustment of the valve position on the controller body.

Abstract: A fluid signal inverting unit includes a motion balance unit having a lever which operates a valve. The balance lever is supported at the opposite ends by a pilot signal chamber and a feedback signal chamber and an intermediate pivot support is coupled to position a back pressure leakport valve. Each chamber includes an outer matched linear metal diaphragm fixedly connected to the aligned end of the lever. Increases in pilot pressure result in the outward movement of the linear diaphragm and corresponding outward and pivotal movement of the lever. The lever tends to move away from and open the valve resulting in a decrease in the output pressure and an inverted output pressure signal which may be further amplified and transmitted to a flow booster relay, and as negative feedback signal to the feedback chamber. Decrease in pilot pressure results in an opposite action and an increase output pressure.

Abstract: A pressure regulator for an anti-skid/anti-spin brake system includes a regulator which adjusts an accumulator pressure to the brake fluid pressure generated during an operator brake application. The adjusted pressure may then be communicated to a wheel brake by a modulator valve during the final phase of an anti-skid cycle. In the absence of an operator brake application a spring biases the regulator so that a reduced accumulator pressure is available for communication to the brake during anti-spin operation. A piston responds to brake pressure generated during an operator brake application to prevent the spring from influencing the adjusted accumulator pressure.

Abstract: A control device having a housing provided with a main lever pivotally mounted thereto by a pivot structure and being operatively associated with a flapper to move the same relative to a leakport in relation to pivotal movement of the main lever. The device has a feedback diaphragm operatively associated with a feedback lever that is pivotally mounted to the housing and is operatively associated with the main lever to cause pivoting thereof upon pivoting movement of the feedback lever by the feedback diaphragm. The device has means for selectively changing the device to be either direct acting or reverse acting.

Abstract: A pneumatic relay responsive to an air input signal whose pressure represents a variable, the relay producing an air output signal proportional thereto. The relay includes an input chamber to which the input signal is fed, this chamber being separated from an output chamber by a diaphragm of elastomeric material. Air from a constant high-pressure supply is fed into the output chamber through an adjustable supply port that is operatively coupled to the diaphragm to cause this port to open to an extent determined by the deflection of the diaphragm in response to the force produced by the pressure of air in the input chamber until a point is reached where the pressure developed in the output chamber attains equilibrium with that in the input chamber.

Abstract: An improvement in a servovalve employing spool-valve-position feedback provided by a feedback spring, wherein the feedback spring centerline is not aligned vertically with the center line of the spool valve, comprising a receiving hole in the spool valve body and a slot in the spool for feedback spring clearance; a pin or ball rigidly attached to the feedback spring with the portions of the pin or the ball which contact the sides of the receiving hole fitting in face to face relation to the inner surface of recesses formed in the slot by the hole.

Abstract: A temperature or pressure sensor that produces a hydraulic pressure signal proportional to temperature or pressure. The sensor or transducer utilizes a plurality of bellows acting on a valve nozzle plate so that the temperature signal which is a gas pressure moves the nozzle plate to control the flow through the nozzle as a function of temperature thus producing a metered pressure proportional to temperature. The bellows are arranged to minimize temperature error in the transducer. Where the temperature sensed is engine inlet temperature the metered pressure may be used to control the fuel through the turbine engine as a function of the engine inlet temperature. This same device is equally utilized in measuring a pressure, such as compressor discharge pressure.

Abstract: A pressure or temperature sensor that translates a pressure or temperature signal into a hydraulic pressure signal. The sensor or transducer utilizes no bearings, levers or pivots that would introduce errors and the control plate is supported within the casing only by bellows. The transducer has use in transmitting a hydraulic pressure signal to the fuel control in a gas turbine in response either to a pressure or temperature signal such as engine inlet temperature or compressor discharge pressure.

Abstract: A pneumatic vacuum regulator (10) is disclosed for supplying a modulated vacuum output signal proportional to an input pressure signal. Upper (18) and lower (20) diaphragms mounted within a housing (14, 16, 36), cooperate therewith to define a fluid chamber (46), a control chamber (58), and an atmospheric vent (104). A spacer (22) between the diaphragms allows the diaphragms to move as a unit in response to sensing subatmospheric pressure in the fluid chamber, atmospheric pressure on one side of the upper diaphragm, and fluid pressure in the control chamber. A valve member (92) is integrally molded into the upper diaphragm and is engageable with an atmospheric valve seat (96) formed around an opening (98) in an upper diaphragm plate (88). A vacuum valve seat (52) is aligned with opening (98) such that the valve member is engageable with either or both valve seats, thus permitting pressure in the fluid chamber to be modulated proportional to the pressure in the control chamber.

Abstract: A force balance instrument providing precision control of pneumatic actuators in response to command pressure signals independent of external forces on the actuator shaft. The instrument includes a high gain signal detection circuit in combination with one or two pilot operated output valves. In the case of two output valves inverse "push-pull" control of a double acting pneumatic actuator is provided. Full supply pressure differential can be developed across the piston of the actuator, permitting to minimize the size of the actuator for any specified output force.The positioner proper controls the position of valve actuator system through a stem connector arm and a feed-back spring. A force balance condition is initially established between the feedback spring and the force of a rolling diaphragm controlled piston assembly for the range of signal pressure P.sub.1 to be used. Any change in this force balance condition because of a change in signal pressure P.sub.

Abstract: A detector for sensing the compressor inlet temperature of a gas turbine engine and for producing an output pressure signal which is used by the fuel control of the engine. The magnitude of the output signal is determined by the position of a valve which changes positions in response to changes in temperature. The response time of the detector is made faster by causing a feedback pressure which acts on the valve to initially change at a slower rate than the output pressure (i.e., to lag the output pressure) when the output pressure changes as a result of temperature variations. The invention can be incorporated either in a self-contained sensor or in an add-on unit which can be retrofitted to existing sensors having relatively slow response characteristics.

Abstract: A thermostat construction having a valve unit for directing a pneumatic signal to a pneumatically operated control device in relation to the force differential between the temperature sensed by the temperature sensing unit thereof and the temperature setting of a temperature setting unit thereof, a lever being pivotally mounted to the construction and being operatively interconnected to the valve unit at a first portion of the lever and to the temperature setting unit and the temperature sensing unit at a second portion of the lever.

Abstract: A housing has an internal opening or cavity within which is a body. Both the opening and body have a relatively large cylindrical median portion and two smaller cylindrical end portions. Three annular diaphragms interconnect the housing and the body and divide that portion of the remaining opening between the two into four gas pressure chambers. The two end chambers are connected through respective ports in the body to pressures representing commanded value and actual value respectively. The two central chambers are connected through respective ports in the body to pressures representing negative feedback and positive feedback respectively. A fifth port communicating with the negative feedback chamber serves as an output pressure port.

Abstract: A pneumatic relay, and more particularly a pneumatic reversing relay, wherein the output decreases with increasing signal pressure. The relay is of the rolling diaphragm type, each rolling diaphragm including a radially outer clamping flange, a radially inner clamping flange and an intermediate rolling wall. Means are provided for securing clamping flanges of the rolling diaphragms against pull-out, creep and relaxation of clamping forces. The valve has a freely floating valve stem having a high degree of pneumatic stability combined with low stem friction. The freely floating operation is obtained by means of an "O" ring surrounding the valve stem and a baffle plate deforming the "O" ring. The relay includes a bias spring whose bias is controlled by the deformation of a metal bonnet housing the bias spring. Spring retainer caps transmit the deformation of the bias spring in a precise and stable manner.

Abstract: An electro-pneumatic current-to-position transducer includes an electric motor having a permanent magnet for a stator and spring restrained coil pivotally suspended about the magnet for a rotor. An input current to the coil induces a mechanical rotation of the coil about the magnet which is proportional to the applied current. Fastened to the coil for rotary movement therewith is a flapper positioned to cover the nozzle of a pneumatic circuit. As current is applied to the coil, the flapper moves toward the nozzle thereby changing the back pressure in the pneumatic circuit. This change in pressure is amplified, then sensed by appropriate pressure-responsive devices and subsequently fed back to a control lever on which the nozzle is mounted, thereby repositioning the nozzle so as to maintain an essentially constant separation between the flapper and the nozzle.

Abstract: A self-contained control device for a system having a first source provided with a changeable fluid pressure value and a second source provided with a changeable vacuum value and having a pressure operated control unit that changes its operating condition in relation to the value of the pressure signal directed thereto, the control device having pneumatically operated control means adapted to be operatively interconnected to the sources and the control unit for increasing the pressure signal from the first source to the unit as the pressure value from the first source increases from a first value thereof to a second value thereof and for thereafter decreasing the pressure signal from the first source to the unit as the pressure value from the first source further increases from the second value thereof to a third value thereof. The control means are adapted to produce the signal in substantially the same manner but at different values for different levels of vacuum at the second source.

Abstract: A control valve includes a single diaphragm as a common wall between an input signal chamber having an input port and an output chamber having a central supply port and an exhaust orifice. The orifice has a seating face parallel to and spaced from the diaphragm. A spring-loaded ball valve unit in the supply passage is aligned with an operator moving with the diaphragm. An increasing input signal first moves the diaphragm to close the exhaust orifice and thereafter moves the operator to open the supply valve. Pressure builds in the output chamber, tending to return the diaphragm and close the supply valve until the output and pilot pressure are balanced. The supply valve then closes. As the exhaust is sealed off, this effectively seals the output chamber. If the signal decreases, the diaphragm uncovers the exhaust orifice until a new balanced state is created.

Abstract: A fluidic square root extractor is disclosed having an amplifier for generating an output in response to an input signal the square root of which is to be extracted, and a squaring means for squaring the output signal and applying it as said feedback signal to the amplifier.

Abstract: A thermostat construction for producing a pneumatic signal in relation to sensed temperature and having a housing provided with a pneumatically operated set point adjustment diaphragm operatively interconnected to a temperature sensor and a pneumatically operated feedback diaphragm to control a valve unit for producing the pneumatic signal in an output chamber of the housing that is defined in part by the feedback diaphragm, a balancing diaphragm being carried by the housing and also defining in part the output chamber thereof.

Abstract: A feathering valve system for modulating the fluid inflow to a selected one of first and second chambers of a movable biased assembly. A controller is electrically coupled to a first and second solenoid operated pilot valve assemblies for selectively (1) maintaining the pilot valve assemblies in a valve closed state without bleed flow through the pilot orifices or (2) supplying a predetermined value electrical signal to either, but not both, of the valve assemblies for actuating one of the assemblies to an open position related to the value of the signal. Fluid under a substantially constant pilot pressure is applied under the poppets of both valve assemblies. Fluid flow is taken from above the poppet of an actuated valve assembly to a respective chamber whereby the movable assembly moves to a position which is a function of the actuating signal value.

Abstract: A fluid pressure gauge type pressure responsive gauge drive having a drive to a sensor controller system with sensor controllers actuatingly engaged at respective adjusted pressure limits with gauge movement travel unimpeded by sensor controller contact in the range of movement between sensor controller pressure limit position settings. The drive may be connected to drive a fluid pressure gauge needle over an indicating dial and upper and lower pressure limit setting needles are adjustable to desired settings over the indicating dial. Calibration structures are provided for a coordinated setting of the gauge dial drive and in the drive of the sensor controller system calibrating each gauge structure for the "C" type bourdon tube installed.

Abstract: A pneumatic control instrument includes a nozzle-flapper system having improved dynamic response characteristics under vibrational conditions. A light-mass, compliant flapper having a high natural frequency covers the nozzle and serves to cushion the impact of the nozzle striking the flapper by moving at the same amplitude of vibration as the nozzle so as to precisely track the nozzle over a wide range of vibrational frequencies and amplitudes.

Abstract: A system having a vacuum source, a pressure source and a pressure operated control device. A pneumatically operated control unit is provided for increasing a pressure signal from the pressure source to the device as the value of the pressure of the pressure source increases from a first value to a second value and for thereafter decreasing the pressure signal from the pressure source to the device as the value of the pressure of the pressure source further increases from the second value thereof to a third value thereof, the control unit producing the signal in substantially the same manner but at different values for different levels of vacuum at the vacuum source thereof. The control unit can include a temperature responsive valve for substantially linearly changing the magnitude of the signal to the device in relation to a certain temperature range.

Abstract: A pressure control device for processing machines having at least one roll which has a stationary core around which a hollow roll which forms the roll proper revolves with radial spacing from the core, the hollow roll supported at its ends on the core and supported on the core in between in the radial direction by a fluid pressure medium disposed in a chamber formed at the core, the fluid pressure medium generating a force acting on the inside of the hollow roll to provide the operating pressure of the roll, with a loading device operated by a fluid pressure medium also applied either to the roll or a counter-roll, either the loading device or roll forming a controlling element, with a control pressure which is derived from the pressure prevailing therein used to adjust a pressure in the other controlled element which has a definite predetermined pressure ratio to the pressure in the controlling element, which pressure control device includes a pressure ratio monitoring device having as inputs the control pre

Abstract: A primary element is connected to a control element of a first fluid pressure relay to move the element to positions at which pressure fluid outputs of relatively small volumes will be generated to represent the element positions. The pressure fluid outputs of the first relay are directed to the input of a second relay which generates pressure values for pressure fluid which are proportional to the first relay outputs in, and at, relatively larger volumes of the pressure fluid.

Abstract: A fluid pressure reproducing relay is described having a high order of accuracy in matching the output pressure to the loading pressure under steady state conditions, having a large flow capacity for both supply and exhaust and which is small in size for its capacity, the relay having a resilient rolling seal with a vented seating arrangement that requires no clamping, having a stabilizing mass loosely attached to a force balance diaphragm assembly and in which a balanced area supply plunger is employed.

Abstract: A range spring sub-assembly providing a variable gradient with minimum hysteresis for the feedback assembly of a pneumatic transmitter. The sub-assembly is constituted by a helical spring whose lower end is secured to the pivoted feedback arm of the feedback assembly and whose upper end is coupled by a span adjustment screw to a fixed arm thereof. The arm porton of the screw extending above the fixed arm is engaged by a zero adjustment knob which rests on top of the fixed arm, whereby when the knob is turned, the screw is axially shifted to vary the tension of the spring coupled thereto. The span adjustment screw has a coupling terminal head that is received within the upper end of the spring and is provided with a set of outwardly projecting pins. The pins are at different heights and are interposed between adjacent convolutions of the spring whereby the pinned convolutions are rendered inactive and the convolutions therebelow remain active.

Abstract: A system having a vacuum source, a pressure source and a pressure operated control device. A pneumatically operated control unit is provided for increasing a pressure signal from the pressure source to the device as the value of the pressure of the pressure source increases from a first value to a second value and for thereafter decreasing the pressure signal from the pressure source to the device as the value of the pressure of the pressure source further increases from the second value thereof to a third value thereof, the control unit producing the signal in substantially the same manner but at different values for different levels of vacuum at the vacuum source thereof. The control unit can include a temperature responsive valve for substantially linearly changing the magnitude of the signal to the device in relation to a certain temperature range.

Abstract: The system includes a way valve of the type provided with a housing, fluid inflow and consumer ports in the housing, and at least one valve member movable in the valve housing for establishing connections between ports. A positioning arrangement receives an electrical input signal and positions the valve member in dependence thereon. A desired-value selector generates a desired-value signal indicative of the desired volumetric flow rate for the flow of fluid into the fluid inflow port and out one of the consumer ports. Transducers sense the position of the valve member and the pressures at the inflow and consumer ports and generate corresponding electrical feedback signals.

Abstract: Pressure regulator system and apparatus for producing a controlled output pressure corresponding to a pre-programmed BCD set point command. Measured values of output fluid pressure emitted from the regulator is applied in BCD signal form to electronic logic in which the measured signal is compared with the signal of the set point. In response to a determined differential between signals, output pressure is changed in a series of repetitive but rate variable differential reduction steps until set point pressure is achieved. In each step a D. C. motor under control of a logic actuated servo-system operates a force balanced air system to adjust a primary control pressure which in turn operatively resets the output pressure of the regulator.

Abstract: The invention contemplates improved hydraulic-pressure control apparatus which will proportionally reflect input-signal changes governing a wide range of output pressures. Use of a separate preamplifier stage, between a signal-pressure stage and a power stage, enables the signal pressure to remain essentially unaffected by load reaction or other transients at the power stage. In the forms described, an input electrical signal determines a step-function program of signal-pressure levels, and the power stage includes a relief valve which so diverts system-line flow to a sump as to assure quick and accurate response of system-line pressure to the instantaneous input electrical-signal level, all without system-pressure overshoot.

Abstract: A primary element is connected to a control element of a fluid pressure relay to move the element to positions at which fluid pressure outputs of the relay will be generated to represent the positions.

Abstract: A function generator is provided which establishes an output signal according to a functional relationship determined by the preformed contour of an easily precut cam member. The function generator includes a variable gain controller section coupled to a proximity sensing motion balance servomechanism which varies the gain of the controller according to the sensed proximity of the servomechanism to the edge of the cam member without physical contact therewith. The cam member's position is in turn determined by an input signal which may be related to the controller input signals or may be an independent signal from a remote source. The gain and consequently the output of the controller is varied according to the functional relationship determined by the precut contour of the cam member.

Abstract: The present invention relates in general to reducing the internal combustion engine exhaust emission polutants. More specifically, it relates to a control device that regulates the amount of exhaust gas being recirculated into the intake manifold of an internal combustion engine such that the exhaust gas recirculation flow is nearly proportional to engine air flow, and is a controlled function of intake manifold vacuum. The flow may be completely inhibited at low engine temperatures and also at times of low manifold vacuum and high engine air flow in order to maintain acceptable driveability.

Abstract: A control valve for delaying the supply of vacuum pressure from an advance port of a carburetor to the distributor of a vehicle when said vehicle is started and/or accelerated.

Abstract: A train of fluid pulses representative of a process variable is processed by digital fluidic circuits and is then converted into an analog fluid pressure signal which is compared to an analog command signal, the difference between the two compared signals being caused to appear in the form of a displacement. This displacement is amplified by means of a fluid servo system, the amplified output of which is utilized for directly driving a control element for a process.

Abstract: A high stability pneumatic pressure regulator is provided by the use of a movable vane and nozzle assembly to operate a valve plug and thereby change the regulator output pressure. Movement of the vane and nozzle assembly is initiated by an adjustable input member which changes the vane to nozzle spacing and subsequently causes the vane and nozzle assembly to move with the valve plug until the normal vane to nozzle spacing is restored. A feedback of the output pressure is used to balance the adjustable input member.

Abstract: An electromagnetic vacuum regulator responds to an electrical signal to supply a regulated vacuum output to vacuum sensitive air-fuel ratio control means in an engine carburetor, the air-fuel ratio control means providing a leaner air-fuel ratio with increasing manifold vacuum. The vacuum regulator includes a regulated vacuum output connected to the air-fuel ratio control means, a constant pressure input connected to a source of constant low vacuum and a variable pressure input normally supplied with the engine manifold vacuum so that the regulated output vacuum is normally always greater than the constant vacuum supplied to the constant pressure input. The carburetor throttle mechanism, however, includes means to actuate a valve opening the variable pressure inlet to the atmosphere during wide open throttle so that the regulated vacuum outlet supplies atmospheric pressure for a richer than normal air-fuel ratio regardless of the electric signal.