LOW-PRESSURE FUEL AND AIR CHARGE FORMING DEVICE FOR AN INTERNAL COMBUSTION ENGINE

Abstract

A throttle body arrangement (10) for an internal combustion engine (12), comprising: a throttle body (18) with a pressure chamber (100) in which a supply quantity of liquid fuel is received through a fuel inlet (104) and an outlet (120), and a throttle bore (20) with an inlet (22) through which air is received; a throttle valve (52) carried by the throttle body (18) with a valve head (54) movable relative to the throttle bore (20) to control fluid flow through the throttle bore (20); a metering valve (28; 152) carried by the throttle body (18) and comprising an electrically driven actuator (72) with a valve element (68) that is movable by the electrically driven actuator (72) between an open position in which fuel can flow from the pressure chamber outlet (120) into the throttle bore (20) and a closed position in which less fuel flows through the metering valve (28; 152) and into the throttle bore (20) compared to when the valve element (68) is in the open position, and wherein less fuel includes the state in which no fuel flows through the metering valve (28); and a valve arrangement (106) comprising a valve (108) movable relative to a valve seat (110) to control fuel flow into the pressure chamber (100) through the fuel inlet (104), and a float (112) coupled to the valve (108) to move the valve (108) into a closed position against the valve seat (110) when a threshold level of fuel is present in the pressure chamber (100), characterized in that The throttle body (18) also has a vent (102) which is connected to the pressure chamber (100) and through which gaseous substances in the pressure chamber (100) can escape from the pressure chamber (100).

Description

TECHNICAL AREA

[0001] The present disclosure relates generally to a fuel and air charge formation device for an internal combustion engine. BACKGROUND

[0002] Many engines use a throttle valve to control or restrict the airflow to the engine according to a requirement. Such throttle valves can be used, for example, in throttle bodies of fuel-injected engine systems. Many such throttle valves include a valve head supported by a stem that rotates to change the orientation of the valve head relative to the fluid flow in a passage and to alter the flow rate of the fluid in and through the passage. In some applications, the throttle valve rotates between an idle position, associated with low-speed and low-load engine operation, and a wide-open or fully open position, associated with high-speed and / or high-load engine operation. Fuel can be drawn from a high-pressure fuel injector (e.g., a fuel injection pump).Fuel pressure of 35 psi or more is provided for mixing with air to supply the engine with a combustible fuel-air mixture. The high-pressure fuel injector can be supported by the throttle body or located downstream of it.

[0003] A control device for a multi-purpose internal combustion engine is described in US 2014 / 0299095 A1. In the control device, which uses a generator as its power supply, the generator includes a main generator coil that powers the stepper motor and an auxiliary generator coil that powers an ignition device for the engine. The device includes an ignition timing control that, when the engine is started with a manual starter, detects when the engine speed reaches or exceeds a predetermined engine speed that does not exceed the linkage speed of a centrifugal clutch, in order to retard the engine ignition timing and thereby prevent the engine speed from dropping below the linkage speed. Furthermore, after a predetermined time has elapsed from the start of the ignition timing retardation, the ignition timing is reset to its normal timing.Accordingly, exceeding the engine speed beyond the connection speed is prevented, even if a delay in engine activation leads to a delay in closing a throttle valve.

[0004] Finally, US 2010 / 0258099 A1 describes a fuel supply system, a corresponding device, and a method. Specifically, it describes a method for operating an engine that includes determining a peak power state for the engine, measuring the engine temperature at that peak power state, comparing the measured temperature with a previously determined temperature associated with a known peak power state of the engine, determining an offset value based on the comparison performed in step 1, and controlling at least one air-fuel mixture supplied to the engine or an ignition timing based on the offset value. Furthermore, various engine fuel supply systems, carburetors, fuel injection systems, and control systems are described. SUMMARY

[0005] The present invention discloses a throttle body arrangement for an internal combustion engine according to independent claim 1 and a throttle body arrangement for an internal combustion engine according to independent claim 16.

[0006] In a first embodiment according to the invention, a throttle body arrangement for an internal combustion engine comprises a throttle body with a pressure chamber in which a supply quantity of liquid fuel is received through a fuel inlet and an outlet, and a throttle bore with an inlet through which air is received, a throttle valve carried by the throttle body with a valve head movable relative to the throttle bore in order to control fluid flow through the throttle bore, and a metering valve carried by the throttle body and comprising an electrically driven actuator.The metering valve has a valve element that is movable by the electrically driven actuator between an open position, in which fuel can flow from the pressure chamber outlet into the throttle bore, and a closed position, in which less fuel flows through the metering valve and into the throttle bore compared to when the valve element is in the open position. The reduced fuel flow includes the state in which no fuel flows through the metering valve. The throttle body assembly further comprises a valve assembly that includes a valve movable relative to a valve seat to control fuel flow into the pressure chamber through the fuel inlet, and a float coupled to the valve to move the valve to a closed position against the valve seat when a threshold level of fuel is present in the pressure chamber.The throttle body also has a vent that is connected to the pressure chamber and through which gaseous substances in the pressure chamber can escape from the pressure chamber.

[0007] In some implementations, a booster venturi nozzle is provided within the throttle bore to capture some of the air flowing through the bore, and fuel flows into the booster venturi nozzle when the metering valve is open. In some implementations, the throttle valve comprises a throttle valve shaft or stem driven to rotate by an electrically driven actuator, and a throttle position sensor is at least partially supported by the stem for rotation with the stem. In some implementations, a control module is also provided, comprising a printed circuit board with a controller that controls the actuator, and wherein at least one drive shaft of the actuator or the throttle valve stem, or a coupler between the drive shaft and the throttle valve stem, extends through the printed circuit board. The actuator may be attached to or supported by the control module.A coupler can be provided between a drive shaft of the actuator and the throttle valve shaft to transmit a rotary motion from the drive shaft to the throttle valve shaft, and the coupler can engage with the throttle body by friction.

[0008] In some implementations, a second metering valve is provided, with one metering valve ensuring fuel flow into the throttle bore at a threshold fuel flow rate or below, and the other metering valve allowing fuel flow into the throttle bore at fuel flow rates above the threshold.

[0009] In some implementations, the pressure chamber is at or within 10% of atmospheric pressure when the engine is running. In some implementations, the pressure chamber is at a super-atmospheric pressure of 6 psi or less when the engine is running.

[0010] In some implementations, the throttle body assembly includes a control module that has a printed circuit board with a controller, and the metering valve is electrically actuated and at least partially controlled by the controller, and the metering valve is supported by the module. In some implementations, the throttle valve includes a throttle valve stem that is driven to rotate by an electrically driven actuator, and the actuator is supported by the module and at least partially controlled by the controller. A pressure sensor may be supported by the module and include an output that communicates with the controller.

[0011] In a second embodiment according to the invention, a throttle body arrangement for an internal combustion engine comprises a throttle body with a pressure chamber in which a supply quantity of liquid fuel is received, and a throttle bore with an inlet through which air is received; a throttle valve supported by the throttle body with a valve head movable relative to the throttle bore to control fluid flow through the throttle bore; a control module with a housing supported by the throttle body and comprising a circuit board and a control unit supported by the housing; and an actuator coupled to the throttle valve to move the throttle valve between a first position and a second position, wherein the actuator is supported by the housing and is at least partially controlled by the control unit. The actuator can be supported by the module.

[0012] In some implementations, the arrangement comprises a metering valve supported by the throttle body, with a valve element movable between an open position, in which fuel can flow from the pressure chamber into the throttle bore, and a closed position, in which fuel is prevented or substantially prevented from flowing through the metering valve into the throttle bore. The metering valve is electrically actuated and at least partially controlled by the control system. In some implementations, the metering valve is directly coupled to the module. In some implementations, the module comprises a housing, and the metering valve is at least partially supported by the housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following detailed description of certain embodiments and the best operating mode is set out with reference to the accompanying drawings, in which: Fig. 1 shows a perspective view of a throttle body; Fig. 2 another perspective view of the throttle body; Fig. Figure 3 shows a sectional view of the throttle body, which shows an electrically actuated throttle valve and a throttle valve position sensor; Fig. 4 is an enlarged, fragmentary sectional view of the throttle body, illustrating a pressure chamber and a steam outlet valve; Fig. Figure 5 shows a sectional view of the throttle body, illustrating a metering valve and a booster Venturi nozzle; Fig. 6 is an enlarged, fragmentary cross-sectional view of a pressure chamber and a steam outlet valve; Fig. Figure 7 shows a sectional view of part of the throttle body, illustrating a metering valve, a booster Venturi nozzle and a pressure chamber; Fig. 8 is a fragmentary sectional view of part of a throttle body with two metering valves; Fig. 9 a sectional view of the throttle body Fig. 8 shows; Fig. 10 is a perspective view of a throttle body with two metering valves and cooling passages; Fig. 11 another perspective view of the throttle body from Fig. 10 shows; Fig. 12 is a sectional view of a throttle body with branched fuel supply passages from a pressure chamber to supply two metering valves; Fig. Figure 13 shows a sectional view of a throttle body with an air intake passage; Fig. 14 is a sectional view of a throttle body with a fuel pressure regulator; Fig. 15 shows a sectional view of a throttle body, which represents a pressure regulator and a pressure chamber; Fig. 16 is a sectional view of a pressure regulator, which may be arranged separately from a throttle body; Fig. Figure 17 shows a sectional view of part of a throttle body with an alternative pressure regulator; Fig. Figure 18 shows a sectional view of an alternative pressure regulator, which is equipped with a throttle body of the type shown in the Fig. can be used of the type shown in 14-17; Fig. 19 shows a fragmentary sectional view of a throttle body, comprising an air intake passage through which fuel is supplied; Fig. 20 is a fragmentary sectional view of a throttle body, comprising an electrically actuated throttle valve; Fig. 21 shows a fragmentary sectional view of a throttle body, comprising an electrically actuated throttle valve and a variable resistance element, such as a potentiometer; Fig. 22 is a top view of a control module, comprising an actuator mounted on a circuit board or housing of the module, and with a cover removed to illustrate internal components; Fig. 23 a perspective view of the in Fig. The control module shown in section 22 is shown; Fig. 24 is a perspective front view of a control module; Fig. Figure 25 shows a rear perspective view of a control module with the cover removed to illustrate certain internal components; Fig. 26 is a perspective view of a charge formation device comprising, among other things, a fuel pump and an electrically driven metering valve, wherein a housing of the device is shown transparently to illustrate internal features; Fig. 27 a sectional view of the in Fig. The device shown in section 26 is shown; Fig. 28 a fragmentary sectional view of the in the Fig. 26 and Fig. The device shown in 27 is to represent a pressure regulator; and Fig. 29 a perspective sectional view of a charge-forming device as in the Fig. 26-28 shows. DETAILED DESCRIPTION

[0014] Referring more closely to the drawings, the Fig. 1 and Fig. 2 a charge-forming device 10, which is attached to an internal combustion engine 12 (schematically represented in Fig. 4) supplies a combustible fuel-air mixture to assist the operation of the engine. The charge-forming device 10 can be applied to a two-stroke or four-stroke internal combustion engine and comprises a throttle body assembly 10 from which air and fuel are drawn for delivery to the engine.

[0015] The arrangement 10 comprises a throttle body 18, which has a throttle bore 20 with an inlet 22 through which air is drawn into the throttle bore 20, and an outlet 24 that is connected to or otherwise communicates with the engine (e.g., an intake manifold 26 thereof). The inlet 22 can, if desired, draw in air from an air filter (not shown), and this air can be mixed with fuel supplied by a fuel metering valve 28, which is supported by or connected to the throttle body 18. The intake manifold 26 is generally in communication with a combustion chamber or piston cylinder of the engine during successive periods of a piston cycle. In a four-stroke engine application, as shown, the fluid can flow through an inlet valve and directly into the piston cylinder.Alternatively, in a two-stroke engine application, air usually flows through the crankcase (not shown) before entering the combustion chamber part of the piston cylinder through an opening in the cylinder wall, which is intermittently opened by the reciprocating piston of the reciprocating engine.

[0016] The throttle bore 20 can have any desired shape, including (but not limited to) a constant diameter cylinder or a Venturi shape ( Fig. 5), wherein the inlet 22 leads to a tapered converging section 30, which leads to a reduced-diameter throat 32, which in turn leads to a tapered diverging section 34, leading to the outlet 24. The converging section 30 can increase the velocity of the air flowing into the throat 32 and create or increase a pressure drop in the throat 32 region. In at least some embodiments, a secondary Venturi nozzle, occasionally called a booster Venturi nozzle 36, can be located within the throttle bore 20, regardless of whether the throttle bore 20 has a Venturi shape or not. The booster Venturi nozzle 36 can have any desired shape and, as in the Fig. 4 and Fig. Figure 5 shows a converging inlet area 38 leading to a reduced-diameter intermediate neck 40, which in turn leads to a diverging outlet 42. The amplifying Venturi nozzle 36 can be coupled to the throttle body 18 within the throttle bore 20. In some embodiments, the throttle body can be cast from a suitable metal, and the amplifying Venturi nozzle 36 can be formed as part of the throttle body—in other words, from the same piece of material cast as a feature of the throttle body when the rest of the throttle body is formed. The amplifying Venturi nozzle 36 can also be an insert that can be coupled to the throttle body 18 in any suitable manner after the throttle body has been formed.In the illustrated example, the amplifying venturi nozzle 36 comprises a wall 44 that defines an internal passage 46 open to the throttle bore 20 at both its inlet 38 and its outlet 42. A portion of the air flowing through the throttle body 18 flows into and through the amplifying venturi nozzle 36, which increases the velocity of this air and reduces its pressure. The amplifying venturi nozzle 36 may have a central axis 48, which may generally be parallel to a central axis 50 of the throttle bore 20 and radially offset from it, or the amplifying venturi nozzle 36 may be oriented in any other suitable manner.

[0017] Referring to Fig. 1-5 The airflow rate through the throttle bore 20 and into the engine is controlled by a throttle valve 52. In at least some embodiments, the throttle valve 52 comprises a head 54, which may include a flat plate, arranged in the throttle bore 20 and coupled to a rotating throttle valve stem 56. The stem 56 extends through a stem bore 58, which intersects the throttle bore 20 and may generally be perpendicular to it. The throttle valve 52 can be driven or moved by an actuator 60 between an idle position, in which the head 54 substantially blocks the airflow through the throttle bore 20, and a fully or widely open position, in which the head 54 provides the least restriction of the airflow through the throttle bore 20. In one example, the actuator 60 may be an electrically driven motor 62 ( Fig. 3 and Fig. 7) be, which is coupled to the throttle valve stem 56 to rotate the stem and thus rotate the valve head within the throttle bore 20. In another example, the actuator 60 can include a mechanical linkage, such as a lever 64, which is attached to the throttle valve stem 56, to which a Bowden cable can be connected to rotate the stem 56 manually as desired.

[0018] The fuel metering valve 28 ( Fig. 7) can have an inlet 66 to which fuel is supplied, a valve element 68 (e.g. a valve head) that controls the fuel flow rate, and an outlet 70 downstream of the valve element 68. To control the actuation and movement of the valve element 68, the fuel metering valve 28 can include or be associated with an electrically driven actuator 72 such as (but not limited to) a solenoid.Among other things, the solenoid 72 can include an outer housing 74, which is received in a cavity 76 in the throttle body 18; a coil 78 wound around a coil former 80, which is received in the housing 74; an electrical connector 82, which is arranged so that it can be coupled to a power source to selectively supply energy to the coil 78; and an armature 84, which is slidably received in the coil former 80 to switch between extended and retracted positions. The valve element can be supported by the armature 84 or otherwise moved by it, relative to a valve seat 86, which can be defined within the solenoid 72 and / or the throttle body 18. When the armature 84 is in its retracted position, the valve element 68 is removed from or spaced away from the valve seat 86, and the fuel can flow through the valve seat.When the armature 84 is in its extended position, the valve element 68 can be closed against or resting on the valve seat 86 to restrict or prevent fuel flow through the valve seat. The solenoid 72 can be constructed as described in U.S. patent application serial number 14 / 896,764. The inlet 68 can be located centrally or generally coaxially with the valve seat 86, and the outlet 70 can be spaced radially outward from the inlet and generally oriented radially outward. Of course, other metering valves, including but not limited to various solenoid valves or commercially available fuel injectors, can be used instead in a particular application if desired.

[0019] In the example shown, the valve seat 86 is defined within the cavity 76 of the throttle body 18 and can be defined by a feature of the throttle body or by a component inserted into and supported by the throttle body. Also in the example shown, the valve seat 86 is defined by a metering nozzle 88 supported by the throttle body 18. The nozzle 88 can be a separate body pressed into or otherwise installed in the cavity 76 and has a passage or orifice 90 through which fuel flows at the inlet 66 to the metering valve 28 before reaching the valve seat 86 and the valve element 68. The flow range of the passages downstream of the nozzle 88 can be larger than the minimum flow range of the nozzle, so that the nozzle provides the maximum limitation of the fuel flow through the metering valve 28.Instead of or in addition to the nozzle 88, a passage of suitable size can be drilled or otherwise formed in the throttle body 18 to define a maximum limitation of the fuel flow through the metering valve 28. The use of a nozzle 88 can facilitate the use of a common throttle body design in multiple engines or in different engine applications where different fuel flow rates may be required. To achieve the different flow rates, different nozzles with orifices having different effective flow ranges can be inserted into the throttle body, while the rest of the throttle body can remain the same. Furthermore, passages of different diameters can be formed in the throttle body 18, in addition to or instead of using a nozzle 88, to achieve a similar effect.

[0020] Fuel flowing through the valve seat 86 (e.g., when the valve element 68 is moved away from the valve seat by retracting the armature 84) flows to the metering valve outlet 70 for delivery into the throttle bore 20. In at least some embodiments, fuel flowing through the outlet 70 is directed into the booster venturi nozzle 36 if a booster venturi nozzle 36 is provided in the throttle bore 20. In embodiments where the booster venturi nozzle 36 is spaced apart from the outlet 70, an outlet tube 92 ( Fig. 5) from a passage or connection defining at least part of the outlet 70, and through an opening 94 in the wall 44 of the amplifying Venturi nozzle to communicate with the passage 46 of the amplifying Venturi nozzle. The tube 92 can extend into and be connected to the neck 40 of the amplifying Venturi nozzle 36, where a negative or sub-atmospheric pressure signal can be of maximum strength and the airflow velocity through the amplifying Venturi nozzle 36 can be of maximum strength. Of course, the tube 92 can open into another area of ​​the amplifying Venturi nozzle 36 if desired.Furthermore, the tube 92 can extend through the wall 44 so that one end of the tube projects into the passage 46 of the amplifying venturi nozzle, or the tube can extend through the passage of the amplifying venturi nozzle so that one end of the tube intersects the opposite wall of the amplifying venturi nozzle and has holes, slots or other features through which fuel can flow into the passage 46 of the amplifying venturi nozzle, or the end of the tube can be inside the opening 94 and submerged or spaced apart from the passage (i.e. not projecting into the passage).

[0021] Fuel can be supplied to the metering valve inlet 66 from a fuel source, and if the valve element 68 is not closed at the valve seat 86, fuel can flow through the valve seat and the metering valve outlet 70 and to the throttle bore 20 to be mixed with the air flowing through it and delivered to the engine as a fuel-air mixture. The fuel source can supply fuel to the metering valve 28 at a desired pressure. In at least some implementations, the pressure can be ambient pressure or a slightly above-atmospheric pressure, up to, for example, 6 psi above ambient pressure.

[0022] To supply fuel to the metering valve inlet 66, the throttle body 18 can have a pressure chamber 100 ( Fig. 4, Fig. 6 and Fig. 7) comprising, in which fuel is obtained from a fuel supply, such as a fuel tank. The throttle body 18 may include a fuel inlet 104 leading to the pressure chamber 100. In a system where the fuel pressure is generally at atmospheric pressure, the fuel flow may be directed into the pressure chamber 100 under the influence of gravity. In at least some embodiments, the fuel pressure chamber may be maintained at or near atmospheric pressure by a vent 102 and a valve assembly 106. The valve assembly 106 may include a valve 108 and may include or be associated with a valve seat 110 such that the valve 108 can be selectively engaged with the valve seat 110 to restrict or prevent the flow of fluid through the valve seat, as described in more detail below.Valve 108 can be coupled to an actuator 112, which moves valve 108 relative to valve seat 110, as explained in more detail below. Vent 102 can be connected to the engine intake manifold or elsewhere as desired, provided the required pressure is achieved in pressure chamber 100 during operation. The fuel level in pressure chamber 100 provides the pressure head or pressure of the fuel that can flow through metering valve 28 when the metering valve is open.

[0023] To maintain a desired fuel level in the pressure chamber 100, the valve 108 is moved relative to the valve seat 110 by the actuator 112 (e.g., a float in the illustrated example), which is housed in the pressure chamber and responds to the fuel level within the chamber. The float 112 can be buoyant in the fuel and pivotally coupled to the throttle body 118, and the valve 108 can be connected to the float 112 for movement as the float moves in response to changes in the fuel level within the pressure chamber 100. When a desired maximum fuel level is present in the pressure chamber 100, the float 112 has moved to a position in the pressure chamber where the valve 108 engages with and closes against the valve seat 110, closing the fuel inlet 104 and preventing further fuel flow into the pressure chamber 100.When fuel flows out of the pressure chamber 100 (e.g., to the throttle bore 20 through the metering valve 28), the float 112 moves in response to the lower fuel level in the pressure chamber, thereby moving the valve 108 away from the valve seat 110, so that the fuel inlet 104 is reopened. When the fuel inlet 104 is open, additional fuel flows into the pressure chamber until a maximum fill level is reached and the fuel inlet 104 is closed again.

[0024] The pressure chamber 100 can also serve to separate liquid fuel from gaseous fuel vapor and air. Liquid fuel settles at the bottom of the pressure chamber 100, while the fuel vapor and air rise to the upper part of the pressure chamber, where the fuel vapor and air can exit the pressure chamber through the vent 102 (and thus be directed into the intake manifold and then into an engine combustion chamber). In the example shown, the valve element 108 is slidably mounted in a passage 114 that leads to the valve seat 110. To reduce any pressure differential that may be present across the valve seat 110 (e.g., due to the vent 102 connected to the intake manifold) and to facilitate the release of any surface tension or other force that might cause the valve 108 to stick to the valve seat 110, a cross-vent passage 116 ( Fig. 6) shall be provided, which connects the valve passage 114 to the pressure chamber 100.

[0025] The pressure chamber 100 can be defined, at least partially, by the throttle body 18, for example, by a recess formed in the throttle body and a cover 118 supported by the throttle body. An outlet 120 of the pressure chamber 100 leads to the metering valve inlet 66. To ensure that fuel is always available at the metering valve 28 when fuel is present in the pressure chamber 100, the outlet 120 can, in at least some embodiments, be an open passage without an intervening valve. The outlet 120 can extend from the bottom or a lower part of the pressure chamber, allowing fuel to flow to the metering valve 28 at atmospheric pressure. A filter or screen 122 ( Fig. 4) A filter or screen may be provided at or within the outlet 120 as desired. As shown here, a disc-shaped screen is provided to filter out any large contaminants that may be present within the pressure chamber 100 and to prevent such contaminants from blocking a downstream passage, port, or the like. An advantage of providing a filter or screen at the outlet 120 is that, when the cover 118 is removed, the filter or screen 122 is accessible for cleaning, replacement, or maintenance, which would be difficult or impossible if the screen were part of the metering valve 28. One or more other filters may be provided instead or additionally elsewhere, generally in the fuel system and in the valve body, if desired.

[0026] When using the valve body arrangement 10, fuel is held in the pressure chamber 100, and thus in the outlet 120 and the metering valve inlet 66, as described above. When the metering valve 28 is closed, no or substantially no fuel flows through the valve seat 86, and therefore no fuel reaches the metering valve outlet 70 or the throttle bore 20. To supply fuel to the engine, the metering valve 28 is opened, and fuel flows into the throttle bore 20, mixes with air, and is delivered to the engine as a fuel-air mixture.

[0027] The timing and duration of the opening and closing of the metering valve can be controlled by a suitable microprocessor or other control unit. The timing of the fuel flow (e.g., injection) or the opening of the metering valve 28 during an engine cycle can alter the pressure signal at the outlet 70 and thus the differential pressure across the metering valve 28 and the resulting fuel flow rate into the throttle bore 20. Furthermore, both the strength of the engine pressure signal and the airflow rate through the throttle valve 52 change considerably between the engine idling and operating with the throttle valve wide open. In summary, the duration for which the metering valve 28 is open for a given fuel flow rate affects the amount of fuel flowing into the throttle bore 20.

[0028] Generally, the engine pressure signal within the throttle bore 20 at the fuel outlet 70 (or at the end of tube 92, if a tube is provided) has a higher value at engine idle than with the throttle wide open. Conversely, the pressure signal at the fuel outlet 70 (or at the end of tube 92) generated by the airflow through the throttle bore 20 and the booster venturi nozzle 36 has a higher value at the throttle wide open than at idle. The relative engine operating state can be determined in various ways, including by an engine speed sensor and / or a throttle valve position sensor 124.

[0029] In the Fig. In the example shown in Figure 3, a throttle valve position sensor 124 is provided so that the system can determine the instantaneous rotational position of the throttle valve 52. The throttle valve position sensor 124 can comprise a magnet 126, which is supported by the throttle valve stem 56, and a magnetically responding sensor 128, which is supported by a printed circuit board 130. The printed circuit board 130, the sensor 128, and one end of the throttle valve stem 56, on which the magnet 126 is located, can be covered by a housing 132, which is coupled to the throttle body 18. The throttle position sensor 124 can be of any suitable type and, although it is shown as a contactless magnetic sensor, it can also be a contact-based sensor (e.g., a variable resistor or potentiometer). The printed circuit board 130 can include a controller or processor used to determine the throttle valve position (e.g., a computer).(idle, fully or widely open, or any position or degree of opening between idle and widely open), or it can connect the output of sensor 128 to a remote controller. Furthermore, if the circuit board 130 includes a controller, the same controller can also be used to control the actuation of the metering valve 28.

[0030] In the illustrated example, the throttle position sensor 124 is located at one end of the throttle valve stem 56, and the throttle valve actuator 60 (e.g., the motor 62 or the valve lever 64) is located at the other end. In such an arrangement, both ends of the throttle valve 52 can be accessible from the outside of the throttle body 18 and have components attached to it such that a holder for the throttle valve stem 56 is arranged between the ends of the stem. In the illustrated implementations, e.g., in the Fig. 1 and Fig. 3. The holder comprises a pin 134 that is inserted into an opening 136 in the throttle body, which intersects the throttle valve stem bore 58 and is received in a groove 138 formed in the periphery of the throttle valve stem 56. The throttle valve stem 56 can rotate relative to the pin 134 but is restrained or prevented from moving axially (i.e., along the axis of the stem 56). To facilitate the assembly of the throttle valve stem 56 in the throttle body 18, the pin 134 can be installed in the throttle body 18 and relative to the stem 56 without requiring access to both ends of the stem, and while the ends of the stem are covered by other components. Other arrangements of a throttle valve 52 can be used, including an arrangement in which both the position sensor 124 and the actuator 60 are located at the same end of the throttle valve stem 56.

[0031] In at least some implementations, a stepper motor 62 can be used to actuate the throttle valve 52, and the stepper motor's rotational position can be used to determine the throttle valve position 52, if desired. For example, a controller used to actuate the stepper motor 62 can track the stepper motor's rotational position, and this can be used to determine the throttle valve position 52. However, when using a stepper motor to actuate the throttle valve 52, it may still be desirable to provide a separate throttle position sensor that provides feedback during actuation of the throttle valve 52 for improved control and position determination.

[0032] Furthermore, at least in implementations without a valve lever 64 coupled to the throttle stem 56, the stops 140, 142 for the idle and wide-open throttle valve positions can be supported by the throttle body 18 and arranged for engagement with the valve head 54. As in at least Fig. As shown in Figure 4, the stops 140, 142 can project into the throttle bore 20 and are depicted as being defined by pins inserted into openings in the throttle body 18 that extend to the throttle bore 20. A pin 140 engages in the valve head, as shown in Figure 4. Fig. Figure 4 shows the idle position of the throttle valve 52, and the other pin 142 engages the valve head 54 to define the wide-open position of the throttle valve 52. After initial installation of the throttle valve 52 in the throttle body, the throttle valve 52 can be rotated between its idle and wide-open positions (i.e., until the head 54 engages the stops 140, 142), and the throttle position sensor 124 and / or the actuator 60 can be used to determine the positions of the throttle valve 52 and store them in a memory device. This allows deviations between throttle bodies due to tolerances and the like to be taken into account, so that precise end positions (e.g., idle and wide open) of the throttle valve 52 can be used in subsequent devices, such as those used to actuate the throttle valve 52 (e.g., by a motor or the like) or the metering valve 28.In at least some implementations, the position of stops 140 and 142 is not adjustable, but the system settings are made based on the current position of the stops in a given throttle body arrangement 10. Of course, stops 140 and 142 could be configured differently and be adjustable. For example, as in the... Fig. 1 and Fig. 2 shown, stops 144, 146 are provided to engage the lever 64 or another part of the throttle valve 52, and the position or location of the stops 144, 146 may be adjustable to allow calibration of the throttle body assembly 10 after assembly.

[0033] As mentioned previously, the position of the throttle valve 52 can be used as a factor in determining the engine fuel requirement, which is met by opening the metering valve and introducing fuel into the throttle bore 20. The fuel flow rate depends on the pressure acting on the fuel, including the pressure upstream of the metering valve 28 (e.g., in the pressure chamber 100) and the pressure downstream of the metering valve (e.g., in the throttle bore 20). In at least some implementations, the metering valve 28 is open during a portion of the engine cycle, which may or may not include the intake stroke, and a sub-atmospheric pressure prevails in the throttle bore 20.With the pressure chamber 100 at or near atmospheric pressure and a sub-atmospheric pressure in the throttle orifice 20 for at least part of the time the metering valve 28 is open, the differential pressure causing fuel to flow into the throttle orifice 20 is greater than one atmosphere. For example, if the pressure chamber 100 is at atmospheric pressure and the pressure at the fuel outlet 70 is 3 psi below atmospheric pressure when the metering valve is open, then the total or net pressure acting on the fuel would be one atmosphere plus 3 psi with respect to the absolute pressure. Even during a compression stroke (when a combustion chamber becomes smaller), the airflow through the Venturi nozzle can provide a negative or sub-atmospheric pressure in the throttle orifice 20.The pressure within the throttle bore 20 could be measured by a sensor, or the information could be provided in a characteristic table, a map, or other stored data collection as a function of certain operating parameters (e.g., engine speed and throttle position). This information can be made available to the controller that actuates the metering valve in order to control the operation of the metering valve as a function of certain engine operating parameters.

[0034] In designs incorporating a booster venturi nozzle 36, the pressure signal at the fuel outlet 70 is related to the pressure within the booster venturi nozzle 36 in the region of the fuel outlet into the booster venturi nozzle 36. The booster venturi nozzle 36 can improve the pressure signal at engine idle by increasing the velocity of a relatively low airflow rate, thereby generating a greater pressure drop at the fuel outlet 70. At idle, as mentioned previously, the engine pressure signal is relatively high and can dominate the pressure drop caused by the airflow through the booster venturi nozzle 36. Nevertheless, the increased airflow velocity in the booster venturi nozzle 36 can facilitate the mixing of air and fuel and the delivery of fuel to the engine, compared to a system in which the fuel is delivered into a lower velocity airflow.This can prevent fuel from accumulating or collecting in the throttle bore 20, and provides the engine with a more consistent fuel-air mixture at low engine speeds and loads, where the fluid flow rate to the engine is relatively low, and thus the engine can be relatively sensitive to changes in the fuel-air mixture.

[0035] To improve the airflow through the booster venturi nozzle 36 when the throttle valve 52 is in or near its idle position, the throttle valve 52 may include a flow straightener arranged to increase the airflow through the venturi nozzle. In the example shown, the flow straightener includes an orifice 150 ( Fig. 2 and Fig. 3) in the throttle valve head 54, which is aligned with the booster venturi nozzle 36 when the throttle is in its idle position. Air can flow through the opening and then through the booster venturi nozzle 36 to ensure a uniform airflow to the booster venturi nozzle 36 and in the fuel outlet area. Instead of or in addition to the opening, other features may be provided, such as a funnel or the like, directed towards the booster venturi nozzle 36 and connected to the idle airflow in the throttle bore 20. Such features may be provided by the throttle valve head 54, by the throttle body, or by both.

[0036] Additionally, when the throttle valve 52 is opened outside of idle and a higher airflow rate is provided through the throttle bore 20, the amplifying venturi nozzle 36 can provide a smoother and less turbulent airflow at the fuel outlet. The airflow within the throttle bore 20 can become turbulent as the air flows around the throttle valve head 54 and the stem 56. The airflow through the amplifying venturi nozzle 36 can be smoother as the air flows through the converging inlet section 38 and the throat 40. Furthermore, the amplifying venturi nozzle 36 can be positioned within the throttle bore 20 to align with the air flowing into the throttle bore 20 when the throttle valve 52 is initially opened from idle.Therefore, the booster venturi nozzle 36 can receive an airflow at idle, at throttle positions outside of idle, and while the throttle valve 52 rotates towards its wide-open position. The booster venturi nozzle 36 can then deliver a more consistent airflow to the fuel outlet 70, ensuring a more uniform pressure signal at the fuel outlet and a more even fuel-air mixture. Consequently, the fuel-air mixture supplied to the engine can be more consistent, resulting in smoother engine operation.

[0037] Subsequently, while a metering valve 28 in the throttle body arrangement 10 of the Fig. Figures 1-7 illustrate the supply of fuel to the engine across the entire range of engine operating conditions; more than one injector or metering valve may be provided. In the diagram shown in the Fig. In the example shown in Figures 8-12, two metering valves 152 and 154 are provided. A first metering valve 152 supplies fuel to the throttle bore 20 through a low-speed fuel outlet 156 for low-speed, low-load engine operation, including idle and some throttle valve positions outside of idle. A second metering valve 154 supplies fuel to the throttle bore 20 through a high-speed fuel outlet 158 ​​for higher-speed, higher-load engine operation. The high-speed fuel outlet 158 ​​may include or be defined by a fuel tube 92 that opens into a booster venturi nozzle 36 as previously described, or it may open directly into the throttle bore 20. The low-speed fuel outlet 156 can open into the booster venturi nozzle 36 (if one is used), the high-speed fuel outlet 158, and the fuel tube 92, as shown in Fig. Figure 9 shows that fuel is discharged from a single point by one of the two metering valves 152, 154. Thus, the first metering valve 152 can be selectively opened below a fuel demand threshold (e.g., 0.1 to 15 lb / h) during engine operation, and the second metering valve 154 can remain closed during this time, or it can also be opened in coordination with, as a function of, or independently of the first metering valve. The second metering valve 154 can be opened during engine operation at or above the fuel demand threshold, and the first metering valve 152 can remain closed during this time, or it can also be opened in coordination with, as a function of, or independently of the second metering valve. The fuel flow for both metering valves 152, 154 can be supplied from the pressure chamber 160, which is divided into two passages 162, 164 ( Fig. 12) can branch to supply both valves with fuel. Furthermore, both valves can be constructed and operate in the same manner as previously described with regard to metering valve 28.

[0038] Regardless of whether one or more metering valves are used, one or more separate fuel passages can be connected to any and up to any metering valve to cool the metering valves, which can be operated at a relatively high voltage (e.g., 8 to 12 volts) and have a switching rate at which more heat than desired can be generated. Such fuel passages are referred to herein as cooling passages 166 and can, as in the Fig. 10 and Fig. 11 shows, leading to a pocket or cavity 168 that surrounds at least part of the metering valves 152, 154. The cooling passage(s) 166 can then lead to a return passage 170 through which the fuel is returned to the pressure chamber 160, as shown in the Fig. 10 and Fig. Figure 11 is shown. Of course, the cooling passages 166 are optional and can be arranged differently if desired. For example, air can be passed through the cooling passages (e.g., from passages branching off from the throttle bore 20 or otherwise formed in the throttle body) to cool the metering valves if required. Engine coolant can also be used to cool the valve(s) if desired.

[0039] Furthermore, as in the Fig. 8 and Fig. Figure 9 shows an air intake passage 172 with a single metering valve (e.g., valve 28) or any one of several metering valves (e.g., valves 152, 154) if more than one metering valve is used. The air intake passage 172 can extend from a portion of the throttle bore 20 upstream of the fuel outlet 156 of the metering valve 152 to which it is associated and be connected to the fuel passage leading to the fuel outlet 156 of the metering valve. In the example shown, the air intake passage 172 leads from an inlet end 22 of the throttle body 18 to the low-speed fuel outlet 156 of the metering valve 152, which can be independent of the high-speed metering valve outlet 158 ​​or, as previously mentioned, connected to it.

[0040] As in the Fig. 9 and Fig. As shown in Figure 12, a nozzle 174 with a passage or orifice 176 of a desired size can be provided in the air intake passage 172. The nozzle 174 can be a separate body that is pressed into the passage 172 or otherwise installed, and air can flow through the orifice 176 before reaching the metering valve 152. The flow range of the passages downstream of the nozzle 174 can be larger than the minimum flow range of the nozzle, so that the nozzle provides the maximum limitation of the airflow through the intake passage 172. Instead of or in addition to the nozzle 174, a passage of suitable size can be drilled or otherwise formed in the throttle body 18 to define a maximum limitation of the airflow through the intake passage 172.The use of a nozzle 174 can facilitate the use of a common throttle body design with multiple engines or in various engine applications where different airflow rates may be required. To achieve the different flow rates, different nozzles with orifices offering different effective flow ranges can be inserted into the throttle body, while the rest of the throttle body can remain the same. Additionally, passages of varying diameters can be formed in the throttle body, either in addition to or instead of using a nozzle, to achieve a similar effect. Furthermore, in some applications, the air intake passage 172 can be capped or plugged to prevent airflow through it.

[0041] In the example where a fuel tube 92 extends into a booster venturi nozzle 36, the intake passage 172 can extend into or be connected to the fuel tube (as shown in dashed lines in Fig. 9 shown), to supply air from the intake passage and fuel from the low-speed metering valve 152 into the fuel tube, where it can be mixed with fuel from the high-speed metering valve 154. Fig. Figure 13 illustrates an example of an intake passage 172 with a throttle body arrangement 10, which includes a single metering valve 28 to provide an airflow into the tube to facilitate fuel flow through the tube and aid fuel-air mixing. Thus, a single delivery point for fuel and intake air into the throttle bore can be provided if desired. Furthermore, the fuel tube can instead or also have an opening 180 directed axially toward the inlet of the throttle bore 20 to draw air into the fuel tube 92. This can facilitate fluid flow in the tube, improve fuel-air mixing, and break any fluid or capillary seal that may form in the fuel tube under certain circumstances.

[0042] In addition to or instead of a nozzle or other flow regulator, the flow rate through the intake passage 172 can be controlled, at least partially, by a valve. The valve could be located arbitrarily along the passage 172, including upstream of the passage's inlet. In at least one embodiment, the valve can be defined, at least partially, by the throttle valve stem. In this example, the intake passage 172 intersects the throttle stem bore, or the intake passage 172 is connected to the throttle stem bore, such that air flowing through the intake passage passes through the throttle stem bore before being discharged into the throttle bore. A void, such as a hole or slot, can be formed in the throttle valve stem 56 (e.g., through the stem or in a region of the stem's periphery), as generally represented by the hole 173 shown in Fig. Figure 8 is shown in dashed lines. As the throttle valve stem rotates, the extent to which the void is aligned with or covered by the intake port changes. This alters the effective or open flow area through the valve, which can change the flow rate of the air supplied from the intake port. If desired, the void can be completely closed to the intake port in at least one throttle valve position, so that airflow from the intake port past the throttle valve orifice is either prevented or substantially inhibited. Thus, the airflow supplied from the intake port to the throttle port can be controlled, at least partially, as a function of the throttle valve position. Furthermore, as shown in Fig. As shown in Figure 19, all or part of the fuel to be discharged from the device can be introduced into the intake passage 172' via a port 175, which may be located downstream of a metering valve or a fuel injector. This can enable a metered flow of fuel into the air flowing through the intake passage and help to atomize the fuel and / or to better mix the fuel and air before the mixture is discharged from the device.

[0043] As already mentioned, the throttle body can also be configured to operate with fuel supplied under positive or above-atmospheric pressure. In at least some implementations, the fuel in the throttle body 18 can be supplied by a fuel pump 190 ( Fig. 15) provided, which may be supported by or arranged remotely from the throttle body 18 (and connected by suitable passages or tubes). The fuel from the fuel pump 190 can be supplied to a pressure regulator 192 with an outlet 194, through which fuel at a desired pressure is delivered to the metering valve 28 or the metering valves 152, 154. Like the fuel pump 190, the pressure regulator 192 can be supported by or arranged remotely from the throttle body 18 and connected to the throttle body by suitable passages, tubes, or the like. From the pressure regulator 192, the fuel can be supplied to a pressure chamber 196, which is connected to the metering valve(s).

[0044] In at least some embodiments, the fuel pump 190 is a pulse pump driven by pressure pulses from the engine (e.g., the engine intake manifold). A suitable type of pulse pump may include a diaphragm actuated by the engine pressure pulses to pump fuel through the intake and exhaust valves as the diaphragm oscillates or moves back and forth. With such a fuel pump 190, the pump does not pump fuel when the metering valve 28 is closed, and no fuel diversion is required at the pressure regulator 192. If a positive displacement fuel pump, such as a gerotor fuel pump, is used, the pressure regulator may include a diversion passage through which fuel is returned at overpressure to the fuel tank or to another area of ​​the system upstream of the pressure regulator.Other pumps may include a diaphragm pump, which is driven mechanically or electrically by a motor subsystem or control system.

[0045] In at least some implementations, such as in the Fig. As shown in Figures 14-16, the pressure regulator 192 can include a diaphragm 198 which is enclosed at its periphery between a main body and a cover. Fig. 16. The main body 200 and the cover 202 are separated from the throttle body and in Fig. In 14-15, the diaphragm 198 is enclosed between the throttle body 18 and a cover 202. In both examples, a preload element, such as a spring 206, can be included between the diaphragm 198 and the cover 204 to provide a force that tends to move the diaphragm towards the main body 200 (in the example of Fig. 16) or of the throttle body 18 (in the example of Fig. 14-15). A fuel chamber 208 is defined between the other side of the diaphragm 198 and the throttle body 18 (or the main body 200). Fuel flows into the fuel chamber 208 through an inlet valve 210 and an inlet passage 212. Fuel is discharged from the fuel chamber 208 through an outlet passage 194. The inlet valve 210 can be coupled to a lever 216, which is rotatably mounted on the throttle body 18 (or the main body 200). When the fuel pressure in the fuel chamber 208 exerts less force on the diaphragm 198 than the spring 206, the diaphragm bends towards the throttle body and engages the lever 216 to open the valve 210 and allow fuel to flow from the fuel pump 190 into the fuel chamber 208.If the fuel pressure in the fuel chamber 208 exerts a greater force on the diaphragm 198 than the spring 206, the diaphragm bends toward the cover 202 and does not move the lever 216 or open the valve 210. Instead, a preload element 220 acting on the lever 216 rotates the lever in the opposite direction to close the valve 210 and prevent further fuel from flowing from the fuel pump 190 into the fuel chamber 208. In this way, the force of the spring 206 on the diaphragm 198 can determine the permissible fuel pressure in the fuel chamber 208. The initial force of the spring 206 can be calibrated or adjusted by a mechanism 222 that sets an initial value for the spring's compression.In the examples shown, the mechanism includes a threaded fastening element 222, which is received in a threaded opening in the cover 202 and advanced towards the spring 206 to further compress the spring, or which is pulled away from the spring to reduce the spring's compression. Of course, other mechanisms can also be used. Other types of pressure regulators can also be used. Fig. Figure 17 shows a throttle body with a pressure regulator 224, which includes a spring-loaded valve element 226 in the form of a valve head 228, which is supported by a valve stem 230 with a spring 232 between the stem 230 and a valve holder 234. The valve element 226 is movable relative to a valve seat 236 by fuel, which acts on the valve head 228 against the spring force. Fig. Figure 18 shows a pressure regulator 240 comprising a spring-loaded valve element in the form of a ball or spherical valve head 242, which is pre-tensioned by a spring 246 against the force of the fuel acting on the head 242 through an inlet 248, engaging a valve seat 244. When the head 242 is displaced from the seat 244, fuel flows through the pressure regulator and out of an outlet 250.

[0046] From the pressure regulator 192, the fuel can flow into the pressure chamber 196 at a generally constant above-atmospheric pressure ( Fig. 15) The pressure chamber 196 may include a float-operated valve 254 that selectively closes a vapor vent 256 when the fuel level within the pressure chamber 196 is at a threshold or maximum level. When the vent 256 is closed, the pressure in the pressure chamber 196 readily exceeds the pressure of the fuel supplied by the pump 190, and further fuel flow into the pressure chamber 196 is substantially restricted or prevented. When the fuel level falls below the threshold level, the float 252 opens the valve 254, and additional fuel is admitted into the pressure chamber 196 from the pressure regulator outlet 194. The outlet 194 from the pressure chamber 196 supplies fuel at super-atmospheric pressure to the metering valve(s), which, when open, introduce fuel into the throttle bore 20.Here too, the metering valves can be opened for all or part of the duration they are open while a sub-atmospheric pressure signal is present in the throttle bore 20.

[0047] Thus, the net pressure acting on the fuel, causing it to flow into the throttle bore 20, can be greater than the fuel pressure supplied to the fuel metering valve(s). If lower fuel flow rates into the throttle bore 20 are desired, the metering valves can, of course, be opened when an overpressure signal is present within the throttle bore 20, where the overpressure in the throttle bore 20 is less than the pressure in the pressure chamber (e.g., set by the pressure regulator).

[0048] In at least some implementations, the throttle body incorporates a pressure chamber that maintains a fuel supply. The fuel in the chamber exerts pressure that increases fuel flow into the throttle body and the mixing of fuel with air before a fuel-air mixture is delivered to the engine. Therefore, a certain amount of overpressure is exerted on the fuel, rather than using sub-atmospheric pressure to draw or suck fuel through a nozzle or similar device. Consequently, fuel can be delivered even when the engine is not running, as the pressure acting on the fuel can cause fuel flow without an engine pressure signal being applied to the fuel.Furthermore, the fuel metering system can include a valve that is selectively opened and closed during an engine cycle to allow fuel flow when open and to prevent or substantially restrict fuel flow when closed. This selective valve operation can occur at engine idle or with the throttle wide open. Additionally, air is mixed with fuel after the fuel has passed through the metering valve(s), rather than a fuel-air mixture being metered.

[0049] Furthermore, at least some throttle body designs do not include a pressure regulator but operate at ambient pressure, with a pressure head acting on the fuel, as previously mentioned. Thus, gravity and the fuel level in a pressure chamber, in combination with a pressure signal in the throttle bore, establish the approximate pressure for fuel supply. In at least some designs, a fuel pump or other fuel source is not required at overpressure or above-atmospheric pressure.

[0050] In at least some implementations, the metering valves are arranged such that fuel flows into the metering valve, which is generally aligned axially with the valve seat and valve element, and fuel is discharged from the metering valve outlet, generally radially outward and spaced radially outward from the inlet. Furthermore, the metering valve outlet can be fed to the throttle bore through relatively large passages (large flow areas) with a nozzle or maximum flow restrictor for the fuel, provided upstream of the throttle bore and, in some implementations, upstream of the metering valve. The airflow in the throttle bore and within a booster venturi nozzle in at least some implementations is used to mix fuel and air and reduce the size of the fuel droplets supplied to the engine.Fuel can be dispensed into the throttle bore through a single orifice in at least some implementations and through one orifice per metering valve in at least certain other embodiments (e.g., one orifice for a low-speed metering valve and a separate orifice for a high-speed valve).

[0051] Furthermore, the pressure chamber can act as a vapor separator and be supported by the throttle body, unlike a remotely located vapor separator that is coupled to the throttle body or a fuel injector via tubes or hoses. Thus, the vapor separator can be located near the point where fuel is injected into the throttle bore, which, among other things, can reduce the likelihood of vapor formation downstream of the separator.

[0052] In at least some implementations, the ratio of the metering valve inlet area to the metering valve outlet area is approximately 0.05 to 2:1 (including implementations with a fuel metering nozzle that defines the minimum inlet flow range). Furthermore, the fuel flow through the metering valves can range from approximately 0.1 to 30 lb / h, and the throttle bodies disclosed herein can be used on engines with power outputs of, for example, approximately 3 to 40 hp. And since the pressure chamber includes a float and a vent, the throttle body can be used with engines operating within approximately 30 degrees of the horizontal.

[0053] Furthermore, in at least some implementations, a microprocessor or other controller can control numerous functions via internal software instructions. These instructions apply a fuel grid map, matrix, or characteristic table (exemplary, non-limiting) in response to the detected current position of the throttle valve 52, engine speed, and crankshaft angle position to select a desired opening time and determine the opening duration of a metering valve 28 for supplying fuel to the throttle bore 20. The microprocessor can also vary the engine's ignition timing to control engine operation in addition to the fuel flow to the engine.

[0054] As already mentioned, the throttle valve 52 can be controlled by an electrically driven actuator 60, which may include, for example, various rotary motors such as a stepper motor 62. The motor 62 can be coupled to the throttle valve stem 56 in any desired manner. An exemplary connection is shown in Fig. Figure 3 shows a coupler 260 with an inlet bore 262, in which a drive element associated with the motor 62 (e.g., a drive shaft 264) is received, and an outlet bore 266, in which one end of the throttle valve stem 56 is received. A partition or cross wall can be provided between the bores if desired. The bores 262, 266, and the stem ends can be non-circular to facilitate their rotation, or the stems 56, 264 can be rotatably connected to the coupler 260 by other means (e.g., by pins, fasteners, welding, gluing, etc.). The coupler 260 can be made of any material and can conform to a certain degree, i.e., be flexible and elastic.While in at least some embodiments the coupler 260 does not rotate, or only rotates slightly, along its axis, so that the rotational position of the throttle valve 52 very accurately tracks the rotational position of the motor 62, the coupler can bend or flex along its axial length to reduce the stress on the motor 62 and the shaft 264 due to slight misalignment of the components during assembly (e.g., due to component tolerances), vibrations, or other influences that occur during operation and over a production run of components. Therefore, at least in some embodiments, springs, levers, and other devices for a more flexible connection of the throttle valve and the motor are not required.

[0055] Furthermore, as in Fig. As shown in Figure 3, the coupler 260 can include a projection 270 extending outward from an outer surface of the coupler. The projection 270 can engage an inner surface of the throttle valve stem bore 58 in the body 18 in which the coupler is received during assembly. The projection 270 can frictionally engage with the body 18 and support the coupler 260 and the stem ends relative to the body with a relatively small engagement surface area, thereby reducing the force required to rotate the throttle valve 52. The projection 270 can dampen vibrations during operation and reduce wear on the coupler 260 and the motor 62 that might otherwise be caused by such vibrations. The coupler can also help to resist unintentional rotation of the throttle valve 52 (e.g.,(through forces on the valve head used) and can enable improved control of the throttle valve by the motor 62, i.e., it can reduce the tilt or play in the connection between the motor and the throttle valve stem 56 to allow more precise control of the throttle valve position. Although in . Fig. Figure 3 shows a projection; multiple projections can be provided, spaced along the axial length of the coupler, having any desired axial length, continuous around the entire circumference, discrete tabs with limited circumferential length, spiral or helix shapes, etc. The projection can also help seal the throttle valve stem bore to reduce or prevent leakage. Representative materials can have a hardness ranging from 20 Shore A to 70 Shore D and / or a modulus of elasticity from 20 MPa to 8 GPa. In at least some implementations, the following non-restrictive and non-exhaustive list of materials can be used: rubber / elastomers, silicones, fluoroelastomers, polyurethanes, polyethylenes, co-polyesters, brass, a 3D-printed material, Delrin®, Viton® / FKM, epichlorohydrin, Texin® 245 or 285, Hytrel® 3078 and Dowlex® 2517.

[0056] Another coupler 271 between the throttle valve stem and the drive motor is in Fig. Figure 20 shows the coupler 271 having a first region with a non-cylindrical cavity 272 in which a non-cylindrical drive shaft 264 of the motor 62 is received, and a second region that is received within an opening formed in a retaining clip 274 coupled to the throttle valve stem 56. The coupler 271 can be received outside the throttle valve stem bore 58, and one or more suitable seals 276 can be provided between the stem 56 and the body 18 either inside or outside the bore 58. The coupler 271 can be made of a metal, polymer, composite material, or any desired material and can be rigid to transmit a rotary motion from the drive shaft 264 to the throttle valve stem 56 accurately and reliably without any twisting or relative rotation between them.The axial position of the throttle valve stem 56 can be held in place by a bracket 278 attached to the body 18.

[0057] One or both of the couplers 271 and the bracket 274 can accommodate misalignment between the drive shaft 264 and the throttle valve stem 56, as well as dampen vibrations and the like. In this arrangement, a throttle valve position sensor can be provided between the drive motor 62 and the throttle valve stem 56, with the coupler 271 carrying a magnet 280 that rotates with the coupler. The magnet 280 can be held axially on the coupler 271 in any suitable manner and is shown to be carried within a cavity of a motor cover 282, and can be held in the other direction by the bracket 274 if desired. Furthermore, the magnet 280 could be located on the opposite side of the circuit board 130 from the motor 62.For example, the magnet 280 could be located on the side of the circuit board 130 that is closer to the choke bore 20, and the motor housing could be located on the other side of the circuit board. A magnetically responsive sensor (e.g., 128) could be located at any position suitable for detecting the changing magnetic field caused by the rotation of the magnet.Even with a motor or other actuator where the rotational position can be determined with suitable accuracy, a separate throttle position sensor may be desirable in at least some implementations to detect any rotation of a coupler or other element between the actuator and the throttle valve and / or to provide a separate indication of the throttle valve position for improved accuracy and / or to allow verification or rechecking of the position determined by the actuator, which may make it possible to correct any error in the indicated position of the actuator or throttle valve.

[0058] Another coupling between the motor 62 and the throttle valve stem 56 is in Fig. Figure 21 shows that this coupling includes a coupler 290, which may be the same as or similar to coupler 271. A non-circular distal end 292 of this coupler 290 can be received in a complementary non-circular cavity in the end of the throttle valve stem 56 to rotatably couple the motor to the valve stem. The coupler 290 or the throttle valve stem 56 can extend through a rotary position sensor, which in this embodiment is represented as a rotary potentiometer 294, supported by the housing and at least partially embedded within it. The potentiometer 294 is shown to be supported by the coupler 290 or the housing 282 such that the resistance of the potentiometer changes when the coupler 290 is rotated. This variable resistance value can be communicated to the controller to enable the determination and control of the throttle valve position.Like the sensor in the magnetic sensor arrangement described above, the potentiometer 294 can be mounted on the circuit board 130 to facilitate coupling with the control and the throttle valve 52.

[0059] As in the Fig. 22 and Fig. As shown in Figure 23, a coupler, throttle valve stem, or motor drive shaft can extend through a printed circuit board 130, which is supported in a housing 298 of a control module 300. As mentioned above, the printed circuit board can include a sensor that responds to changes in the magnetic field of the magnet caused by the rotation of the magnet, in order to determine the rotational position of the magnet and the throttle valve stem. In the illustrated embodiment, the motor 62 comprises a shell or housing with supports 302 that are attached to the printed circuit board 130 and / or to the module housing 298 in any desired manner, including, but not limited to, suitable fasteners or heat-treated pins.In at least some embodiments, the motor 62 is located on the opposite side of the printed circuit board 130 from the throttle valve head 54, and the drive shaft 264 of the motor (and / or an associated adapter) or the throttle valve stem 56 extends through an opening in the printed circuit board 130. The motor 62 can be of any desired type, including, but not limited to, a stepper motor, hybrid stepper motor, DC motor, brushed or brushless motor, printed circuit board motor, and a piezoelectric actuator or motor, including, but not limited to, a so-called squiggle motor. If desired, a gearbox or gear set can be used between the motor 62 and the throttle valve stem 56 to increase or decrease the speed of the throttle valve relative to the motor power.

[0060] As in the Fig. 24 and Fig. As shown in Figure 25, in addition to or instead of the motor 62, an electrically actuated metering valve 28 or a fuel injector of any desired design, including but not limited to those already described herein, can be coupled to the circuit board 130 and extend outwards from the housing 298 to be received in a bore of the body 18, as previously shown and described. In applications with more than one metering valve 28, all or fewer than all metering valves can be directly coupled to the circuit board 130 (i.e., with power leads 304 for actuating the solenoid directly coupled to the circuit board) and supported by the module 300 that comprises the circuit board 130. In at least some embodiments, the metering valves 28 and the drive shaft 264 of the motor 62 are generally arranged parallel to each other and for receipt in bores spaced apart along the throttle bore 20. Not in the Fig. Figures 22-25 show an optional rear cover for the housing 298, which can partially or completely enclose the motor 62 and the circuit board 130. The circuit board 130 can include a controller 306, such as a microprocessor. The microprocessor 306 can communicate electrically with, among other things, the motor 62, the metering valve(s) 28, and various sensors that can be used in the system, including the throttle valve position sensor.

[0061] Other sensors can also be used and communicate with the microprocessor 306 and can be mounted directly on the circuit board 130. For example, as in the Fig. 22, Fig. 23 and Fig. As shown in Figure 25, one or more pressure sensors 308, 310 can be mounted on the circuit board. A first pressure sensor 308 can be connected to the intake manifold or to a region with a pressure representative of the intake manifold pressure. This can facilitate the control of the fuel-air mixture (e.g., operation of the metering valve(s)) as a function of the intake manifold pressure. In the illustrated embodiment, the housing 298 includes a conduit in the form of a cylindrical tube 312 extending outwards from the housing. The tube 312 can be formed from the same material as the region of the housing 298 from which it extends, for example, by being an integral part of the housing. The tube 312 can extend into a passage in the body 18 that is open towards the throttle bore 20 adjacent to the outlet end 24 of the throttle bore.The tube 312 or the first sensor 308 could generally also be connected to the intake manifold, for example, by being coupled to a line that is connected at its other end to a fitting or valve open to the intake manifold. A second pressure sensor 310 can be connected to atmospheric pressure via another tube 314 or line, which may be arranged similarly to the one described with respect to the first sensor 308. This can facilitate the control of the fuel-air mixture (e.g., operation of the metering valve(s)) as a function of atmospheric pressure. Other or additional pressure sensors, including one or more fuel pressure sensors, can be used with the module 300 and can be directly coupled to the circuit board 130 if desired.

[0062] The motor, metering valve(s), and sensors can be connected to the circuit board independently, i.e., without any of the other components mounted on the board, or in any combination including some or all of these components, as well as other components not listed here. As mentioned earlier, the circuit board can include at least part of an ignition control circuit that manages the generation and discharge of energy for ignition events in the motor, including the timing of these events. This circuit can include the 306 microprocessor, allowing the same microprocessor to control the ignition circuit, the throttle valve position, and the position of the metering valve(s). Naturally, more than one microprocessor or control unit can be provided, and they can be located on the same or different circuit boards, as desired.In at least some implementations, all the different combinations of these components are located in the same control module for easy assembly and use with the throttle body and with the engine and the vehicle or tool with which the engine is used.

[0063] In at least some implementations, the ignition circuit can include one or more coils located adjacent to a flywheel that incorporates one or more magnets. The rotation of the flywheel moves the magnets relative to the coils (usually a primary, secondary, and / or trigger coil) and induces an electrical charge in the coils. The ignition circuit can also include other elements suitable for controlling the discharge of electricity to a spark plug (as in either an inductive or capacitive discharge ignition circuit) and / or for storing the energy generated in the coils (as in a capacitive discharge ignition circuit). However, a microprocessor need not be included in the arrangement containing the coil. Instead, the microprocessor (e.g.,306), which is associated with the charge-forming device, which may be operable to be connected to and / or control one or more devices associated with the throttle valve, as mentioned herein, also control the timing of ignition events, for example by controlling one or more switches associated with the arrangement including the coils and located adjacent to or supported by the engine. Therefore, the coils may be arranged separately relative to the throttle body and its control module, but are controlled by the throttle body control module. In addition, sensors or signals may be provided from the arrangement comprising the coils to the control module and the control unit 306 to, among other things, better control the ignition timing.Without limiting the possibilities, such signals can relate to the temperature of the assembly, including the coils or the motor; such signals can relate to the motor speed; and / or such signals can relate to the motor position (e.g., crankshaft angle). Furthermore, the energy induced in the coils can be used to power one or more of the 306 microprocessors, a throttle valve actuator, a metering valve actuator, a fuel injector, and the like. In this way, the two modules (one with the coils on the motor and the other on or associated with the throttle body) can establish an efficient and symbiotic relationship.

[0064] In at least some implementations, the engine speed can be controlled by the module using a combination of throttle valve position and ignition timing, both of which can be controlled by the 306 microprocessor, which, as described above, can be located within the 300 module. The throttle valve position affects the flow rate of air and fuel to the engine, and the ignition timing can be advanced or retarded (or certain ignition events can be skipped entirely) to vary engine performance characteristics, as is known. Thus, the system can control both the throttle valve position and the ignition timing to manage the flow rate of a combustible air-fuel mixture to the engine and when the combustion event occurs within an engine cycle.

[0065] Another implementation of a fuel and air charge forming device 320, which can be a throttle body, is described in the Fig. Figures 26-28 illustrate this. In this embodiment, the device 320 increases the pressure of the fuel supplied to it and delivers a metered fuel flow into the throttle bore 20. The device may include or be connected to a fuel pump 322, which increases the pressure of the fuel supplied to the device 320. In the example shown below, the fuel pump 322 is supported by the device 320 and is formed integrally with it.

[0066] Specifically, fuel from a source (e.g., fuel tank) enters the throttle body 18 via a fuel inlet 324 in a cover 326, which is attached to the main throttle body 18. From the fuel inlet, the fuel flows to the fuel pump 322 through a pump inlet passage 328 formed in the main body 18. In this example, the fuel pump 322 includes a fuel pump diaphragm 330, which is enclosed around its circumference between a pump cover 332 and the main body 18 or another component. A pressure chamber 334 is defined on one side of the diaphragm 330 and communicates with engine pressure pulses via a pressure signal inlet 336, which may be defined in a fitting formed in the pump cover 332.A suitable conduit can be coupled at one end to the fitting 336 and communicate with the engine intake manifold, the engine crankcase, or another location from which engine pressure pulses can be communicated to the pressure chamber. The other side of the diaphragm 330 defines a fuel chamber 338 with the main body. Fuel enters the fuel chamber 338 via an inlet valve 340, and fuel exits the fuel chamber under pressure via an outlet valve (not shown). The inlet and outlet valves can be separate from the fuel pump diaphragm, or one or both of them can be formed integrally with the diaphragm, for example, by flaps in the diaphragm that move in response to a pressure differential across the flaps relative to separate valve seats. In at least some implementations, such as in . Fig. As shown in Figure 27, the inlet and outlet valves can be supported by and the corresponding valve seats can be defined in a wall 342 of the main body or an intermediate body 344 enclosed between the pump cover 332 and the main body 18.

[0067] The unenclosed central portion of the diaphragm 330 moves in response to a differential pressure above it. When the central portion of the diaphragm 330 moves toward the cover 332, the volume of the fuel chamber 338 increases and the pressure within it decreases, opening the inlet valve 340 and allowing fuel into the fuel chamber. When the central portion of the diaphragm 330 moves away from the cover 332, the volume of the fuel chamber 338 decreases and the pressure within it increases. This pumps the fuel under pressure out of the fuel chamber and through the outlet valve. The fuel pump 322 can be designed and operated similarly to a diaphragm fuel pump, such as those used in certain carburetors.

[0068] The fuel discharged from the fuel chamber 338 flows into a pump outlet passage 346, which may be formed at least partially in the main body 18. From the pump outlet passage 346, the fuel flows into a pressure chamber 348, which is similar to the one described above in terms of Fig. This pressure chamber 348 can be described in Section 15. This pressure chamber 348 can also include a float-operated valve 350 that selectively closes a vapor vent 352 (which can be coupled to a line directing the vapor to any desired location, such as, but not limited to, the intake manifold, the fuel tank, an activated carbon canister, or elsewhere, as desired) when the fuel level inside the pressure chamber 348 is at a threshold or maximum level. When the vent 352 is closed, the pressure in the pressure chamber 348 readily exceeds the pressure of the fuel supplied by the pump 322, and further fuel flow into the pressure chamber 348 is significantly restricted or prevented. When the fuel level falls below the threshold level, the float 354 opens the valve 350, and additional fuel is admitted into the pressure chamber 348.

[0069] Fuel in the pressure chamber 348 is connected to a fuel pressure regulator 356, which may be supported by the main body 18 or another body associated with the main body, or it may be located remotely and coupled to the pressure chamber 348 via a suitable line. The pressure regulator 356 may be of any desired design and, as described above, Fig. 17 or Fig. 18 described. As in the Fig. 26 and Fig. As shown in 28, the pressure regulator 356 is similar to the one shown and in relation to Fig. The pressure regulator described in section 17 is received in a bore 358 in the main body 18. After the regulator is installed, the bore is sealed by a plug 360 to prevent fuel from escaping. The pressure regulator valve is exposed to the super-atmospheric fuel in the pressure chamber 348 via a valve seat 362. At least when the fuel pressure exceeds a threshold pressure, the valve head 364 is moved away from the valve seat, and the fuel flows through the pressure regulator to a diverting passage 366, which can lead to any desired location, including the fuel pump inlet 324, the fuel tank, or elsewhere. This limits the maximum fuel pressure within the pressure chamber to a desired level.

[0070] Fuel in the pressure chamber 348 is also connected to a fuel metering valve 370 via a pressure chamber outlet passage 372, which can be formed wholly or partially within the main body 18, if desired. The metering valve 370 is accommodated in a bore 374 of the main body 18, which intersects the fuel outlet passage 372 and has an outlet port that leads to, or is directly open to, the throttle bore 20. A valve seat or metering orifice 376 of the valve bore 374 is located between the fuel outlet passage 372 and the outlet port or throttle bore 20, so that the fuel flow into the throttle bore is controlled or metered by the valve 370. The metering valve 370 can be of any desired design, including, but not limited to, the valves already described herein.

[0071] In at least some embodiments, the metering valve 370 can comprise a body that is axially movable relative to the valve seat 376 or within a tapered orifice to modify the flow area of ​​the valve and thus the fuel flow through the valve and to the throttle bore 20. In the illustrated example, the valve body includes at its distal end a needle 378 extending through the valve seat 376, and the valve body includes a shoulder adapted to engage the valve seat to restrict or prevent fuel flow through the valve seat when the valve is in a closed position. An axial movement of the valve body can be controlled by an actuator 380, which may be electrically driven.The actuator 380 may be or include a solenoid, or it may be a motor, such as, but not limited to, the motor types listed herein with respect to at least the throttle valve actuator(s). In at least some embodiments, the motor 380 rotates the valve body, which may include external threads engaging with threads formed in the bore 374, such that this rotation of the body causes the valve body to move axially relative to the valve seat 376. The motor 380 could instead move the body linearly forward and / or backward with respect to the valve seat. The motor may be driven by a controller, such as a microprocessor 306, as described above.Since the fuel at the metering valve 370 is under pressure, it will flow into the throttle bore 20 as long as fuel is present and the shoulder is not in contact with the valve seat, and at least in certain conversions no fuel injector or the like is required.

[0072] As in Fig. As shown in Figure 29, the fuel inlet 324 to the charge-forming device 320 can include a valve arrangement 382 to control the fuel flow into the charge-forming device. For example, the valve can close to prevent fuel from being forced into and through the charge-forming device at a certain pressure. In the illustrated example, the valve arrangement includes a float 384 that is received in an inlet chamber 386 defined between the cover 326 and the main body 18. The float 384 can be coupled to or supported by a valve 388 to selectively open and close the fuel inlet 324. When the fuel level in the inlet chamber 386 is at a desired maximum level, the float 384 lifts the valve 388 into engagement with a valve seat, and the fuel flow into the inlet chamber 386 is inhibited or completely stopped.When fuel pump 322 pumps fuel and fuel flows into throttle bore 20, as described above, the fuel level in inlet chamber 386 will be below the maximum level at least at certain times, and the float will open the valve to allow fuel flow into the inlet chamber. This prevents, for example, a higher upstream pressure acting on the fuel (e.g., increased fuel tank pressure) from forcing too much fuel into the charge-forming device and potentially causing a higher than desired fuel flow rate into the throttle bore, since the float and valve limit the volume of fuel that can be in the inlet chamber. In this way, the fuel pressure in the charge-forming device and the fuel flow rates can be controlled within the desired ranges. As also described in... Fig.As shown in Figure 29, the vent 352 can lead from the pressure vessel into the inlet chamber 386. Fuel vapor in the inlet chamber can condense back into liquid fuel in the inlet chamber, which generally contains cooler fuel from a tank or other source.

[0073] While the forms of the invention disclosed herein represent currently preferred embodiments, many others are possible. It is not intended to mention here all possible equivalent forms or branches of the invention. It is understood that the terms used herein are merely descriptive and not limiting, and that various modifications may be made without altering the essence or scope of the invention.

Claims

[1] A throttle body assembly (10) for an internal combustion engine (12), comprising: a throttle body (18) with a pressure chamber (100) in which a supply quantity of liquid fuel is received through a fuel inlet (104) and an outlet (120), and a throttle bore (20) with an inlet (22) through which air is received; a throttle valve (52) carried by the throttle body (18) with a valve head (54) movable relative to the throttle bore (20) to control fluid flow through the throttle bore (20); a metering valve (28; 152) carried by the throttle body (18) and comprising an electrically driven actuator (72) with a valve element (68) that is movable by the electrically driven actuator (72) between an open position in which fuel can flow from the pressure chamber outlet (120) into the throttle bore (20) and a closed position in which less fuel flows through the metering valve (28; 152) and into the throttle bore (20) compared to when the valve element (68) is in the open position, and wherein less fuel includes the state in which no fuel flows through the metering valve (28); and a valve arrangement (106) comprising a valve (108) movable relative to a valve seat (110) to control fuel flow into the pressure chamber (100) through the fuel inlet (104), and a float (112) coupled to the valve (108) to move the valve (108) into a closed position against the valve seat (110) when a threshold level of fuel is present in the pressure chamber (100), characterized by , that The throttle body (18) also has a vent (102) which is connected to the pressure chamber (100) and through which gaseous substances in the pressure chamber (100) can escape from the pressure chamber (100). [2] The throttle body arrangement (10) according to claim 1, wherein a booster venturi nozzle (36) is provided within the throttle bore (20), such that a portion of the air flowing through the throttle bore (20) flows through the booster venturi nozzle (36) and a portion of the air flowing through the throttle bore (20) flows around the booster venturi nozzle (36), and wherein fuel flows into the booster venturi nozzle (36) when the metering valve (28; 152) is open. [3] The throttle body arrangement (10) according to claim 1, which further comprises a second metering valve (154) and wherein a metering valve (152) provides the fuel flow into the throttle bore (20) at a threshold fuel flow rate or below and the other metering valve (154) enables the fuel flow into the throttle bore (20) at fuel flow rates above the threshold. [4] The throttle body arrangement (10) according to claim 1, wherein the pressure chamber (100) is at or within 10% of atmospheric pressure when the motor (12) is in operation. [5] The throttle body arrangement (10) according to claim 1, wherein the pressure chamber (100) is at a super-atmospheric pressure of 6 psi or less when the motor (12) is in operation. [6] The throttle body arrangement (10) according to claim 1, wherein the throttle valve (52) comprises a throttle valve stem (56) which is driven to rotate by an electrically driven actuator (60), and wherein a throttle position sensor (124) is at least partially carried by the stem (56) to rotate with the stem (56). [7] The throttle body arrangement (10) according to claim 6, which further comprises a control module (300) comprising a printed circuit board (130) with a control unit that controls the actuator (60), and wherein at least one of a drive shaft (264) of the actuator (60) or of the throttle valve shaft (56) or a coupler (260) between the drive shaft (264) and the throttle valve shaft (56) extends through the printed circuit board (130). [8] The throttle body arrangement (10) according to claim 7, wherein the actuator (60) is attached to or supported by the control module (300). [9] The throttle body arrangement (10) according to claim 6, comprising a coupler (260) between a drive shaft (264) of the actuator (60) and the throttle valve shaft (56) to transmit a rotary motion from the drive shaft (264) to the throttle valve shaft (56), wherein the coupler (260) engages frictionally in the throttle body (18). [10] The throttle body arrangement (10) according to claim 7, which further comprises a pressure sensor (308, 310) which is carried by the module (300) and has an output which communicates with the control. [11] The throttle body arrangement (10) according to claim 1, which further comprises a control module (300) having a housing (298) and a circuit board (130) with a control unit, wherein the metering valve (28; 152) is electrically actuated and at least partially controlled by the control unit, and wherein the circuit board (130) and the metering valve (28; 152) are supported by the housing (298). [12] The throttle body arrangement (10) according to claim 11, wherein the throttle valve (52) comprises a throttle valve stem (56) which is driven to rotate by an electrically driven actuator (60), and wherein the actuator (60) is supported by the housing (298) and is at least partially controlled by the control unit. [13] The throttle body arrangement (10) according to claim 11, wherein the metering valve (28; 152) comprises a body which is rotated by the actuator (72) to move the metering valve body relative to a valve seat (86). [14] The throttle body arrangement (10) according to claim 1, which further comprises a fuel pump (190) which is supported by the throttle body (18) and provides fuel delivery into the throttle bore (20) at a pressure above atmospheric pressure. [15] The throttle body arrangement (10) according to claim 14, comprising a fuel inlet (324) and an inlet chamber (386) in the throttle body (18), and an inlet valve (382) with a float (384) which responds to a fuel level in the inlet chamber (386) such that the float (384) moves the inlet valve (382) into a closed position when a fuel threshold level is present in the fuel chamber (386) to prevent excess fuel from being forced through the fuel inlet (324) into the throttle body (18). [16] A throttle body assembly (10) for an internal combustion engine (12), characterized by : a throttle body (18) with a pressure chamber (100) in which a supply quantity of liquid fuel is received, and a throttle bore (20) with an inlet (22), through which air is absorbed; a throttle valve (52) carried by the throttle body (18) with a valve head (54) movable relative to the throttle bore (20) to control fluid flow through the throttle bore (20); a control module (300) with a housing (298) supported by the choke body (18) and comprising a circuit board (130) and a control unit supported by the housing (298); and an actuator (60) coupled to the throttle valve (52) to move the throttle valve (52) between a first position and a second position, wherein the actuator (60) is supported by the housing (298) and is at least partially controlled by the control system. [17] The throttle body arrangement (10) according to claim 16, which further comprises a metering valve (28; 152) supported by the throttle body (18) with a valve element (68) that is movable between an open position in which fuel can flow from the pressure chamber (100) into the throttle bore (20) and a closed position in which less fuel flows into the throttle bore (20) through the metering valve (28; 152) compared to when the valve element (68) is in the open position, wherein less fuel includes the state in which no fuel flows through the metering valve (28; 152), and wherein the metering valve (28; 152) is electrically actuated and at least partially controlled by the control system. [18] The throttle body arrangement (10) according to claim 17, wherein the metering valve (28; 152) is directly coupled to the housing (298). [19] The throttle body arrangement (10) according to claim 18, wherein the metering valve (28; 152) is at least partially supported by the housing (298).

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