Claims:WE CLAIM:
1. An air intake modulating device (10) comprising:
• an air flow passage (12) with an inlet (122) and an outlet (124);
• a throttle valve (14) disposed within said air flow passage (12);
• a cavity (16) transverse to said air flow passage (12);
• a displacing element (18) for said throttle valve (14), said displacing element (18) coupled to a throttling means and configured to slide along said cavity (16) and linearly displace said throttle valve (14);
• a magnet (22) affixed to said displacing element (18) with the axis thereof aligned with axis of displacement of said displacing element (18); and
• a throttle valve position sensor (20), wherein said sensor (20) is a Hall effect sensor mounted on an operative external surface of said cavity (16);
wherein said sensor (20) comprises at least one vertical Hall effect sensing element (204) and configured to sense linear position of said throttle valve (14) by sensing angular position of said magnet (22).
2. The air intake modulating device (10) as claimed in claim 1, wherein said sensor (20) has a housing (201) and a printed circuit board (203), said housing (201) encasing said printed circuit board (203) on which said sensing element (203) is embedded.
3. The air intake modulating device (10) as claimed in claim 2, wherein said sensor (20) is mounted to have the plane of the printed circuit board (203) parallel to the axis of displacement of said magnet (22) and perpendicular to the surface on which said housing (201) is mounted.
4. The air intake modulating device (10) as claimed in claim 1, wherein said sensor (20) comprises a circular vertical Hall sensing element (204).
5. The air intake modulating device (10) as claimed in claim 1, wherein said sensor (20) comprises a plurality of vertical Hall sensing elements arranged in a polygonal shape.
6. The air intake modulating device (10) as claimed in claim 1, wherein said sensor (20) is a three-dimensional Hall effect sensor.
7. The air intake modulating device (10) as claimed in claim 1, wherein said air intake modulating device is a throttle body.
8. The air intake modulating device (10) as claimed in claim 1, wherein said air intake modulating device is a carburetor.
, Description:FIELD
The present disclosure relates to the field of intake systems of engines of vehicles. Particularly, the present disclosure relates to throttle position sensors.
DEFINITIONS
As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
The expression ‘air intake modulating device’ used hereinafter in this specification refers to, but is not limited to, devices installed in the air intake system of an internal combustion engine, and comprise a modulating element, usually a throttle valve, which is manipulated for controlling the quantity of air flowing into the engine. The term ‘air intake modulating devices’ refers to carburetors and throttle bodies that are used in the intake systems of internal combustion engines.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
In the intake system of an engine of a small vehicle such as a two-wheeled vehicle or a three-wheeled vehicle, a throttle valve in a device such as a carburettor or a throttle body is manipulated to control the intake of the engine, either the air-fuel ratio or just the air intake, to control the power derived out of the engine. A throttle valve is generally a butterfly valve rotating with a shaft and mounted with a rotary throttle position sensor (TPS) in the passage of the air between the air filter and the intake manifold of the engine. However, linearly displacing throttle valves in throttle bodies as well as carburettors are also known. A cavity is formed transverse to the air flow passage of the throttle body, along which the linearly displacing element of the valve is configured to slide. The advantage of a linear air intake modulating device (i.e., a throttle body or a carburettor with a linearly displacing valve) is the linear increase in air intake with respect to the extent of opening/lifting or closing/lowering of the throttle valve, the effect of which is smooth variation in power delivered by the engine.
A throttle position sensor (TPS) is used to monitor the position of the throttle valve, either directly or indirectly, i.e., by directly sensing the position of the throttle valve or indirectly by sensing the displacement of the throttling means. The user opens or closes the throttle valve by manipulating the throttling means such as by twisting an accelerator grip on a handlebar of a two-wheeled or a three-wheeled motor vehicle or by pressing with the leg on an accelerator pedal in a four-wheeled vehicle. The output of the TPS is generally sent to an engine control unit (ECU) which either controls the supply of fuel and/or ignition timing based on the signal or, in a feedback loop control system, controls the position of the throttle, or both. By monitoring position of the throttle valve, the ECU manages the load of the engine for optimizing fuel efficiency, engine performance including power output, and the like.
A throttle position sensor can be of contact type, such as a potentiometer type sensor, or a non-contact type, such as an inductive sensor, a magnetoresistive sensor or a Hall effect sensor. A Hall effect sensor comprises a sensing element made of semiconductor material mounted on a microchip or a printed circuit board. The sensor has at least a voltage input terminal, a voltage output terminal and a ground terminal. The microchip is in turn mounted on an external surface of the throttle body, which senses position of a magnetic element while the magnetic element is displaced alongwith the valve. The output of the sensing element is calibrated in terms of positions of the throttle valve between and including the lower mechanical stop position and wide open throttle (WOT).
For sensing position of a linearly displacing throttle valve in air intake modulating devices (hereinafter referred to as “linear air intake modulating devices”), a Hall effect sensor with a linear output is most preferred. A linear output Hall effect sensor has a signal amplifying element and a voltage regulating element incorporated in the circuit. A magnet is attached to the linearly displacing element of the valve, with the poles aligned along the axis of displacement. Conventionally, a planar Hall effect sensor is used for TPS application. A planar Hall Effect sensor is only sensitive to magnetic flux along an axis perpendicular to the face of the PCB. Such a planar Hall effect sensor needs the chip to be mounted with its plane parallel to the axis of displacement of the magnet, in order to bring the Hall effect sensing element of the sensor inside sufficient magnetic flux density, which is measured in SI units of Tesla which equals 10-4 gauss. In case of a planar Hall effect sensor, the upper limit for the air gap between the sensing element and the magnet is 2mm, beyond which the accuracy of the sensor’s output is compromised. Any compromise in sensor accuracy could lead to non-optimal fuel consumption and/or non-optimal ignition timing. Thus, the wall thickness of a linear throttle body implemented in an engine of a two-wheeled vehicle typically must be 2mm or less. Moreover, a magnet with a gauss value of at least 1500 must be used, in order to use a planar Hall effect sensor.
Thus, in the use of a planar Hall effect sensor for throttle valve position sensing, the dimensional accuracy of the walls of the cavity of a linear throttle body should be within 2mm or less. To achieve such a dimensional accuracy, high precision manufacturing processes are required. Moreover, in case of any inaccuracy in dimension would lead to part rejection, since, with thinner walls, the throttle body is incapable of sustaining the high thermal and dynamic stresses, and with thicker walls, the air gap between the sensing element of an externally mounted planar Hall effect sensor and the magnet would become excessive so as to affect the sensor’s accuracy.
Therefore, there is felt a need of a linear air intake modulating device, such as a linear throttle body or a carburetor with a linear throttle valve, of an internal combustion engine with a throttle valve position sensor that alleviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
The object of the present disclosure is to provide an air intake modulating device of an internal combustion engine with a throttle valve position sensor.
Another object of the present disclosure is to provide a linear air intake modulating device with a throttle valve position sensor.
Yet another object of the present disclosure is to provide a linear air intake modulating device with a throttle valve position sensor which has high wall thickness of the throttle body.
Still another object of the present disclosure is to bring about reduction in rejection of throttle bodies in manufacturing.
Yet another object of the present disclosure is to provide a linear throttle body with a throttle valve position sensor which has low overall cost.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a linear air intake modulating device. The throttle body comprises an air flow passage with an inlet and outlet, a throttle valve disposed within the air flow passage, and a cavity transverse to the air flow passage. A displacing element for the throttle valve is coupled to a throttling means and is configured to slide along the cavity and linearly displace the throttle valve. A magnet is affixed to the displacing element with the axis thereof aligned with axis of displacement of the displacing element. The linear throttle body is provided with a throttle valve position sensor which is a Hall effect sensor is mounted on an operative external surface of the cavity. The sensor comprises at least one vertical Hall effect sensing element and is configured to sense linear position of the throttle valve by sensing angular position of said magnet. The sensor has a housing and a printed circuit board, the housing encasing the printed circuit board on which the sensing element is embedded. The sensor is mounted to have the plane of the printed circuit board parallel to the axis of displacement of the magnet and perpendicular to the surface on which the housing is mounted. The air intake modulating device is a throttle body or a carburetor.
In an embodiment, the sensor comprises a circular vertical Hall sensing element. In another embodiment, the sensor comprises a plurality of vertical Hall sensing elements arranged in a polygonal shape. In yet another embodiment, the sensor is a three-dimensional Hall effect sensor.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The linear air intake modulating device of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figures 1a and 1b illustrate a front view and a side view of a linear air intake modulating device of prior art;
Figure 2 illustrates a sectional view of the linear air intake modulating device of Figure 1 taken across the throttle valve position sensor;
Figure 3 illustrates a throttle valve position sensor of prior art;
Figures 4a and 4b illustrate a front view and a side view of a linear throttle body of the present disclosure;
Figures 4c and 4d illustrate a front view and a side view of a carburetor of the present disclosure;
Figure 5 illustrates a sectional view of the linear throttle body of Figure 4a taken across the throttle valve position sensor; and
Figure 6 illustrates a throttle valve position sensor of the present disclosure;
Figure 7 illustrates a schematic diagram showing configuration of a vertical Hall effect sensor with respect to a linearly displacing magnet; and
Figure 8 is a plot of sensor output voltage v/s linear displacement of a magnet measured in a trial of the linear throttle valve with a throttle valve position sensor of the present disclosure.

LIST OF REFERENCE NUMERALS
10’ linear air intake modulating device of prior art
20’ throttle valve position sensor of prior art
10 linear air intake modulating device of the present disclosure
20 throttle valve position sensor of the present disclosure
12 air flow passage
122 air inlet
124 air outlet
14 throttle valve
16 transverse cavity
18 valve displacing element
20 Hall effect sensor
201 sensor housing
202 housing bush
203 printed circuit board
204 sensing element
205 input terminal
206 output terminal
207 ground terminal
22 magnet
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an”, and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including” and “having” are open ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.
When an element is referred to as being “mounted on”, “engaged to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Terms such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
Figures 1-2 illustrate a linear air intake modulating device 10’ and Figure 3 shows a throttle valve position sensor of prior art. The throttle valve position sensor 20’ referred to in Figures 1-3 is a planar Hall effect sensor. As seen in Figures 1a and 1b, the sensor is mounted on the transverse cavity 16 extending from the air flow passage 12. A sensing element 204 embedded on a printed circuit board 203 is shown in Figure 3. The sensor housing 201 is configured for mounting through bushes 202. The plane of the printed circuit board (PCB) 203 of the sensor 20’ is ‘horizontally’ mounted on the surface of the cavity 16, as shown in Figures 1a and 2. While such an arrangement minimizes the air gap between the sensing element 204 and the magnet 22, the strength of the walls of the transverse cavity 16 is compromised. Moreover, a magnet of high gauss value (~1500 gauss) is required. A throttle valve position sensor is required for a linear air intake modulating device which allows construction of the air intake modulating device with relatively thicker walls, without compromising on the performance delivered by the sensor.
The present disclosure envisages a linear air intake modulating device such as a linear throttle body or a carburetor with a linearly displacing valve with a vertical Hall effect sensor mounted thereupon, the construction of which is explained hereforth with the help of Figures 4-6.
The linear air intake modulating device 10 (such as a linear throttle body shown in Figures 4a, 4b, or a carburetor as shown in Figures 4c, 4d) is disposed between the air filter and the intake manifold of the engine. The linear air intake modulating device 10 comprises an air flow passage 12. A cavity 16 is formed transverse to the air flow passage 12. A throttle valve 14 is configured to be displaced between a ‘wide open’ position and a mechanical stop position across the section of air flow passage 12 along the axis of the cavity 16. A valve displacing element 18 which is coupled to a throttling means, is configured to displace slidingly along the cavity 16 displaces the valve 14 between the two extreme positions. The user opens or closes the throttle valve by manipulating the throttling means (not shown in Figures) such as by twisting an accelerator grip on a handlebar of a two-wheeled or a three-wheeled motor vehicle or by pressing with the leg on an accelerator pedal in a four-wheeled vehicle. A magnetic element, preferably a diametric magnet 22, is affixed to the displacing element 18. The axis of the magnet 22 is kept parallel to the axis of displacement of the displacing element 18. A throttle valve position sensor 20 is mounted on an external surface of the cavity 16 adjacent to the magnet 22. An input terminal 205 of the throttle valve position sensor 20 is supplied with an input voltage from the electrical battery of the vehicle. An output terminal 206 of the throttle valve position sensor 20 is coupled to a control unit (not shown in Figures) wherein output voltage of the sensor is measured. A ground terminal 207 of the throttle valve position sensor 20 grounded through the body of the vehicle. The output of the TPS is sent to an engine control unit (ECU) which either controls the supply of fuel and/or ignition timing based on the signal in case of a fuel injection system using a throttle body, only the ignition timing based on the signal in case of a carburetted system, or, in a feedback loop control system, controls the position of the throttle valve, or both. By monitoring the position of the throttle valve, the ECU manages the load of the engine for optimizing fuel efficiency, engine performance including power output, and the like.
The throttle valve position sensor 20 shown in Figures 4-6 comprises at least one vertical Hall effect sensor. While a planar Hall effect sensing element is sensitive to field perpendicular to the face of the housing of the printed circuit board, a vertical Hall effect sensing element is sensitive in an axis that is parallel to the printed circuit board such as the X or Y axis. The vertical Hall effect sensor 20 measures the angular position of the magnetic field of the magnet 22 in the plane of the printed circuit board 203, for sensing linear position of the throttle valve 14, as shown in Figure 7. Therefore, the sensor output virtually becomes independent of the air gap. The sensor 20 has the sensing element 204 embedded on the printed circuit board 203. The sensor 20 is mounted ‘vertically’ on the surface of the cavity 16 with the plane of the printed circuit board 203 parallel to the axis of displacement of the magnet 22 and perpendicular to the surface of the cavity 16, as shown in Figures 4a, Figure 4c and 5. The various sensor configurations, which incorporate one or more vertical Hall sensing elements, include a circular vertical Hall (CV) sensor, a three-dimensional Hall effect sensor, a sensor with a plurality of vertical Hall sensing elements arranged in a polygonal shape, and so on. A circular vertical Hall (CV) sensor comprises a circular array of vertical Hall effect sensing elements. A three-dimensional Hall effect sensor comprises a two vertical Hall effect sensing elements and a planar Hall effect sensing element.
The output voltage of the sensor 20 is proportional to the linear displacement of the magnet 22, as is illustrated through the following table 1 as well as the corresponding plot shown in Figure 8. In the trial, the sensor used was an angle sensor which uses a circular vertical Hall (CVH) sensing element. The integrated circuit (IC) of the sensor is configured to measure linear displacement and generate proportional output voltage. Measurements were obtained for input voltage (Vcc) 5V. The air gap between the front edge of the sensor and the magnet surface was upto 8mm. The magnet used was an NdFeB diametric magnet of 13mm length, 5.2mm width and 2.5mm height. The strength of the magnet used is 300 gauss.
Linear displacement (mm) Sensor output voltage (V)
0 0.501
1 0.626
2 0.788
3 0.982
4 1.218
5 1.456
6 1.699
7 1.94
8 2.182
9 2.422
10 2.657
11 2.891
12 3.121
13 3.344
14 3.566
15 3.797
16 4.033
17 4.273
18 4.494
Table 1
Thus, a highly linear curve of the output voltage of the sensor v/s the linear displacement of the magnet was obtained. Moreover, a magnet of substantially lower strength, i.e., 300 gauss as compared to 1200 gauss, was used to obtain results comparable to those obtained with the planar Hall effect sensor of prior art. Most importantly, the air gap maintained between the front edge of the sensor (i.e., edge of the printed circuit board) and the surface of the magnet was upto 8mm, which is more than thrice the upper limit of the air gap required by a planar Hall sensor to provide comparable results. Cost associated with the magnet is, thus, reduced.
Hence, the use of a vertical Hall effect sensor for throttle position sensing in a linear air intake modulating device allows having thicker walls for the cavity through which the displacing element of the throttle valve slides. The air intake modulating device such as a throttle body or a carburetor with thicker walls is better able to sustain thermal and dynamic stresses. Requirement of precision values for dimensions of the air intake modulating device is relaxed and thus, manufacturing becomes less costly, or in other words, low-precision manufacturing methods can be incorporated. With less stringent requirements on dimensional precision, rejection rate of air intake modulating devices is reduced.
While the aforementioned trial was conducted on a linear throttle body, the same results can be obtained with a carburetor having a linearly displacing throttle valve. The linear throttle body with a vertical Hall effect sensor of the present disclosure was tested for a single-cylinder engine of a two-wheeled or a three-wheeled vehicle. However, the same can be implemented for multiple cylinder engines of larger cubic capacity. The application of the linear throttle body with a vertical Hall effect sensor of the present disclosure extends to internal combustion engines driven by combustion of liquid and/or gaseous fuels.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a linear air intake modulating device with a throttle valve position sensor, which:
• can have high wall thickness of an air intake modulating device and thus requires low-precision manufacturing methods;
• reduces rejection of air intake modulating device in manufacturing; and
• has lower overall cost.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components are omitted so as to not unnecessarily obscure the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.