GB1582642A - Fluid flow rate control apparatus - Google Patents

Description

(54) FLUID FLOW RATE CONTROL APPARATUS (71) We, NISSAN MOTOR COMPANY LIMITED, a corporation organized under the laws of Japan, of No. 2, Takara-cho, Kanagawa-ku, Yokohama City, Japan, (formerly of 2, Takaramachi, Kanagawa-ku, Yokohama City, Japan) do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an apparatus for controlling the fluid flow rate through a duct.

When fluid is conveyed through, for example, a conduit or pipe under pressure, a flow rate is usually controlled by a metering orifice and a suitable actuator such as an electromagnetic valve, etc. The actuator, based on a control signal applied thereto, controls the flow rate of fluid by changing the pressure applied to the fluid or a cross sectional area of the pipe. However, the actuator mechanically controls the flow rate so that it is unable to abruptly change the flow rate due to a relatively large transient time inherent in the mechanically operated actuator. Furthermore, in the case where the flow rate is controlled by "open" and "close" operations of the actuator, undesirable pulsating flow is caused.

It is an object of the present invention to provide improved apparatus for controlling the fluid flow rate through a duct.

According to the present invention there is provided apparatus for controlling fluid flow rate comprising a duct having first and second portions of relatively larger and smaller cross-section respectively, said second portion being downstream of said first portion, first means disposed in said first portion for electrically charging a fluid stream flowing through said first portion, second means disposed about the second portion for establishing an electric field to control the fluid flow rate by interaction between the charged fluid and said field, and third means for varying the magnitude of said field.

Embodiments of the present invention will now be described with reference to the accompanying drawings of which: Figure 1 is an illustration of a first preferred embodiment of the present invention; Figure 2 is a cross sectional view taken along a line B-B' of Figure 1; and Figure 3 is an illustration of a second preferred embodiment of the present invention.

Reference is now made to Figure 1, which illustrates a first preferred embodiment of the present invention. A metering orifice 2 is provided in a suitable fluid pipe 4 for, as is well known, regulating the amount of fluid flow passing therethrough. Charging means 5 is provided downstream of the metering orifice 2, comprising a plurality of pipes 6 each of which is made of metal and has a small cross sectional area, charging electrodes 8 each arranged between two small pipes 6; and insulators 1 0a and 10b for positioning an assembly, which consists of the pipes 6 and the electrodes 8, in the pipe 4 as well as electrically insulating the assembly from the pipe 4.Each of the small pipes 6 are electrically connected to a positive terminal 24a of a high voltage power source 24, and on the other hand, the power source 24 is electrically connected, through its negative terminal 24b, to a mesh electrode 18 which is fixedly installed in the pipe 4 in an electrically insulative manner by means of a member 20 made of an insulative material. A cylindrical electrode 30 is provided upstream of the mesh electrode 18 and is surrounded by insulative material 16. The electrode 30 is connected to the control unit 26 which receives the control signal Vs controlling the voltage applied to the electrode 30.

With this arrangement, fluid is applied to the pipe 4 in a direction as indicated by an arrow 3. Then, the fluid is, in this case, positively charged when passing through the metal pipes 6 in that the electrodes. 8 are connected to the positive terminal 24a of the power source 24, the output potential of which is, for example, within a range from several to several tens of kilo-voltages. The power source 24 is set within a range of several to several tens of kilo-voltages. With this arrangement, the fluid flow passing through the cylindrical electrode 30 can be controlled by the control signal Vs. In more detail, if the electrode 30 is positively charged, the electrodes 30 expels the fluid flow upstream thereof so that the flow rate decreases in dependence of the positive voltage applied to the electrode 30.On the contrary, if the electrode 30 is negatively charged, the electrode 30 in turn attracts the fluid flow upstream thereof with the result that the flow rate increases in dependence of the negative voltage apPlied to the electrode 30. The charged fluid is then discharged when passing through the mesh electrode 18 connected to the negative terminal 24b.

The arrangement of Figure 1 can be modified in various manners. By way of example, the mesh electrode 18 can be omitted.

Furthermore, the orifice 2 is not necessarily positioned as in Figure 1, but, can be positioned in a discretionary portion, for example, downstream of the charging means 5 or the mesh electrode 18. Still furthermore, the small pipes 6 of the charging means 5 can be replaced by electrodes of needle type, or mesh type.

Figure 2 is a cross sectional view taken along a line B-B' in Figure 1. As shown, the cross section of the charging means 5 is cylindrical, however, it may be, for example, oval.

Figure 3 is an illustration of a second preferred embodiment of the present invention in which the charging means 5 is replaced by charging means 5 having a needle electrode 30' and a plate electrode 32. Electrodes 30' and 32 are mounted on insulators 34 and 36 respectively and are connected to terminals 24b and 24a respectively. The manner in which the flow rate is controlled is understood from the description of Figures 1 and 2, so that further description will be omitted for brevity.

In the above, the control signal Vs is usually d-c voltage, however, a-c voltage also available. Furthermore, a train of pulses can be employed, in the case of which, in order to control the flow rate, a duty factor of the pulse is changed.

The apparatus embodying the present invention is useful when, for example, controlling the amount of fuel and/or air applied to an internal combustion engine. In this case, an electrical signal, which represents an engine operational parameter such as the amount of air taken into the engine, is used as the control signal Vs.

Attention is directed to our Application No. 22928/77 (Serial No. 1 582 641) from which this application was divided and which discloses and claims fluid flow rate control apparatus.

WHAT WE CLAIM IS: 1. Apparatus for controlling fluid flow rate comprising a duct having first and second portions of relatively larger and smaller cross-section respectively said second portion being downstream of said first portion, first means disposed in said first portion for electrically charging a fluid stream flowing through said first portion, second means disposed about the second portion for establishing an electric field to control the fluid flow rate by interaction between the charged fluid and said field, and third means for varying the magnitude of said field.

2. Apparatus as claimed in claim 1, wherein said first means comprises a plurality of conductive tubes mounted parallel to the direction of flow of said fluid stream for passing the fluid stream therethrough and electrically connected to a source of direct potential.

3. Apparatus as claimed in claim 1 or claim 2, wherein said second means comprises a cylindrical hollow conductive member.

4. Apparatus as claimed in claim 3, wherein said cylindrical hollow conductive member is embedded in a body of an insulative material.

5. Apparatus as claimed in any preceding claim, further comprising discharging means disposed downstream from said second means to electrically discharge said charged fluid.

6. Apparatus as claimed in claim 5, wherein said discharging means comprises a meshed electrode maintained at a potential of a polarity opposite to the polarity of said charged fluid.

7. Apparatus as claimed in claim 1, wherein said first means comprises a plate and an opposed electrode.

8. Apparatus as claimed in claim 8, wherein said opposed electrode includes a needle point.

9. Apparatus as claimed in any preced

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. the pipe 4 in a direction as indicated by an arrow 3. Then, the fluid is, in this case, positively charged when passing through the metal pipes 6 in that the electrodes. 8 are connected to the positive terminal 24a of the power source 24, the output potential of which is, for example, within a range from several to several tens of kilo-voltages. The power source 24 is set within a range of several to several tens of kilo-voltages. With this arrangement, the fluid flow passing through the cylindrical electrode 30 can be controlled by the control signal Vs. In more detail, if the electrode 30 is positively charged, the electrodes 30 expels the fluid flow upstream thereof so that the flow rate decreases in dependence of the positive voltage applied to the electrode 30.On the contrary, if the electrode 30 is negatively charged, the electrode 30 in turn attracts the fluid flow upstream thereof with the result that the flow rate increases in dependence of the negative voltage apPlied to the electrode 30. The charged fluid is then discharged when passing through the mesh electrode 18 connected to the negative terminal 24b. The arrangement of Figure 1 can be modified in various manners. By way of example, the mesh electrode 18 can be omitted. Furthermore, the orifice 2 is not necessarily positioned as in Figure 1, but, can be positioned in a discretionary portion, for example, downstream of the charging means 5 or the mesh electrode 18. Still furthermore, the small pipes 6 of the charging means 5 can be replaced by electrodes of needle type, or mesh type. Figure 2 is a cross sectional view taken along a line B-B' in Figure 1. As shown, the cross section of the charging means 5 is cylindrical, however, it may be, for example, oval. Figure 3 is an illustration of a second preferred embodiment of the present invention in which the charging means 5 is replaced by charging means 5 having a needle electrode 30' and a plate electrode 32. Electrodes 30' and 32 are mounted on insulators 34 and 36 respectively and are connected to terminals 24b and 24a respectively. The manner in which the flow rate is controlled is understood from the description of Figures 1 and 2, so that further description will be omitted for brevity. In the above, the control signal Vs is usually d-c voltage, however, a-c voltage also available. Furthermore, a train of pulses can be employed, in the case of which, in order to control the flow rate, a duty factor of the pulse is changed. The apparatus embodying the present invention is useful when, for example, controlling the amount of fuel and/or air applied to an internal combustion engine. In this case, an electrical signal, which represents an engine operational parameter such as the amount of air taken into the engine, is used as the control signal Vs. Attention is directed to our Application No. 22928/77 (Serial No. 1 582 641) from which this application was divided and which discloses and claims fluid flow rate control apparatus. WHAT WE CLAIM IS:

1. Apparatus for controlling fluid flow rate comprising a duct having first and second portions of relatively larger and smaller cross-section respectively said second portion being downstream of said first portion, first means disposed in said first portion for electrically charging a fluid stream flowing through said first portion, second means disposed about the second portion for establishing an electric field to control the fluid flow rate by interaction between the charged fluid and said field, and third means for varying the magnitude of said field.

2. Apparatus as claimed in claim 1, wherein said first means comprises a plurality of conductive tubes mounted parallel to the direction of flow of said fluid stream for passing the fluid stream therethrough and electrically connected to a source of direct potential.

3. Apparatus as claimed in claim 1 or claim 2, wherein said second means comprises a cylindrical hollow conductive member.

4. Apparatus as claimed in claim 3, wherein said cylindrical hollow conductive member is embedded in a body of an insulative material.

5. Apparatus as claimed in any preceding claim, further comprising discharging means disposed downstream from said second means to electrically discharge said charged fluid.

6. Apparatus as claimed in claim 5, wherein said discharging means comprises a meshed electrode maintained at a potential of a polarity opposite to the polarity of said charged fluid.

7. Apparatus as claimed in claim 1, wherein said first means comprises a plate and an opposed electrode.

8. Apparatus as claimed in claim 8, wherein said opposed electrode includes a needle point.

9. Apparatus as claimed in any preced

ing claim wherein the third means comprises a variable voltage divider connected across a source of direct potential.

10. Apparatus for controlling the fluid flow rate through a duct substantially as described with reference to the accompanying drawings.