A THROTTLE POSITION SENSING SYSTEM
Field of invention
The present invention relates to a throttle position sensing system, particularly, the present invention relates to a throttle position sensing system for use in a two & three wheeled vehicles having handle bar as a driving means.
Background of the invention
In internal combustion engine (petrol) the fuel-air mixture is ignited by a spark generated by a spark plug. The fuel-air mixture in the petrol engines in prepared in the carburetor. The requirement of the fuel/air ratio in the engine cylinder varies with the different operating condition. The carburetor is provided with a throttle and the position of the throttle determines the fuel/air ratio in the fuel-air mixture. Depending on the air/fuel ratio the time and intensity of the spark should also change for complete combustion of fuel-air mixture in the engine cylinder. The two & three wheelers such as scooters, motorcycles & mopeds commonly use an engine ignition system based on capacitive discharge method known as Capacitive Discharge Ignition (CDI). In Capacitive Discharge Ignition (CDI) the energy generated by a magneto is transferred to a storage capacitor and then released as a high voltage pulse via a step up transformer to spark plug to ignite the fuel-air mixture inside the cylinder. More efficient engine design and new government regulation on pollution control require a CDI with variable spark timing as most economical choices available. Due to the fact that the fuel/air ratio is controlled by the throttle position, it is required to change the timing of the spark with the change in the throttle position.
The rotation of the throttle is sensed through a bracket mounted reed switch and a magnet or by sliding contacts. Figure 1 (a) and figure 1 (b) describes different parts of the reed switch type throttle position sensor. Figure 2(a) and figure 2 (b) illustrates reed-switch type throttle position sensor are mounted with the help of the bracket near the throttle. Reed-switch comprises contacts mounted on ferromagnetic reeds sealed in a glass tube,
designed for actuation by an external magnetic field. The external magnetic field is applied by the magnet. The relative movement between the reed-switch and the magnet is achieved with the help of a cable which connects the throttle pipe to the bracket mounted reed switch and the magnet assembly. The reed-switch controls only the time of the spark and does not provide any control over the intensity of the spark. As can be noticed from figure 2(a) and 2 (b) the operation of the reed switch is divided into two zones namely ON zone for 0 to 38 degree rotation of the throttle and OFF zone for 38 to 98 degree rotation of the throttle. Moreover, the reed-switches have following disadvantages:
(a) Handling of reed switches in the production line is difficult due to the glass body.
(b) Reed switches also provides lesser accuracy as at rating change with respect to
bending and cutting of leads of reed switch required in production.
(c) Bracket used for mounting the reed-switch and magnet may get jammed due to the
accumulation of the dust and dirt or due to the corrosion.
(d) The reed switch does not provide protection from short circuit, therefore the reed
switch may damage if the output of the reed switch is shorted in the field.
(e) The reed switch and magnet assembly mounting arrangement is also subjected to
the normal wear and tear which affects the life and reliability of the system.
Figure 3 illustrates existing control switch of the right hand handle bar of the two wheeled vehicle.
There has been always a need of a sensing system which not only provides controlled spark timing and spark intensity but also overcomes the afore-said problems of the prior existing sensors or sensing systems.
Objects of the present invention
The main object of the present invention is to provide a throttle position sensing system. Another object of the present invention is to provide a non-contact type of the electronic throttle position sensing system.
Still another object of the present invention is to provide an electronic throttle position sensing system which overcomes at least one of the problems of prior art.
Summary of the invention
The present invention provides a throttle position sensing system which overcomes the problems of existing reed switch based throttle position sensing system and provides a non-contact type throttle position sensing system. The throttle position sensing system is accurately measure the position of the throttle and thereby it accurately achieves the variability in spark timing. The throttle position sensing system of the present invention has high operational life cycle as compared to the prior existing system.
Statement of invention
Accordingly, the present invention relates to a throttle position sensing system for use in
two & three wheeled vehicles with a handle bar coupled to a throttle pipe, said system
comprising:
a sensor assembly having a Hall Effect transducer located on a printed circuit board
(PCB) inside a control switch mounted on the handle bar;
a magnet located inside the control switch; said magnet is mounted on the throttle pipe
such that the magnet is movable from one first position to plurality of second positions
with the movement of the throttle pipe;
a processing means configured to receive input from the sensor assembly and provide
signal for controlling the spark timing and intensity of spark.
Brief description of drawings
Figure 1 (a) illustrates a prior existing bracket mounted reed-switch and magnet for
throttle position sensing.
Figure 1 (b) illustrates assembly of the parts in existing reed-switch type throttle position
sensing system.
Figure 2 (a) illustrates the mounting of prior existing throttle position sensing system on
vehicle for 0 to 38° rotation of throttle i.e. for OFF zone.
Figure 2 (b) illustrates the mounting of prior existing throttle position sensing system on
vehicle for 38 to 98° rotation of throttle i.e. for ON zone.
Figure 3 illustrates the mechanical configuration for an existing control switch with
mechanical module of the right hand handle bar for the two wheeled vehicle.
Figure 4 illustrates the basic mechanism of the throttle position sensing system of the
present invention.
Figure 5 is an exemplary illustration of a block diagram of the throttle position sensing
system with the capacitive discharge ignition (CDI) unit according to an embodiment of
the present invention.
Figure 6(a) illustrates circuit configuration of the throttle sensing system according to the
present invention.
Figure 6(b) illustrates the variation of voltage output from the sensor assembly with the
rotation of throttle pipe.
Figure 7(a) illustrates control switch of the right hand (RH) handle bar of the two & three
wheeled vehicle integrated with the throttle position sensor assembly of the present
invention.
Figure 7(b) is an exemplary illustration solid body cross sectional view of the control
switch of the right hand (RH) handle bar of the two wheeled vehicle integrated with the
throttle position sensor assembly of the present invention.
Figure 8 illustrates control switch in the right hand (RH) handle bar of the two wheeled
vehicle for mounting the sensor assembly of the throttle sensing system of the present
invention.
Figure 9 is an exemplary illustration of different views of the control switch in the right
hand (RH) handle bar for the throttle position sensing system of to the present invention.
Figure 10 illustrates a proto-trial of control switch for the throttle position sensing system
according to the present invention.
Description of the present invention:
Accordingly, the present invention provides a throttle position sensing system for use in
two & three wheeled vehicles with a handle bar coupled to a throttle pipe, said system
comprising:
a sensor assembly having a Hall Effect transducer located on a printed circuit board
(PCB) inside a control switch mounted on the handle bar;
a magnet located inside the control switch; said magnet is mounted on the throttle pipe
such that the magnet is movable from one first position to plurality of second positions
with the movement of the throttle pipe;
a processing means configured to receive input from the sensor assembly and provide
signal for controlling the spark timing and intensity of spark.
In an embodiment of the present invention the processing means is coupled to a capacitive discharge ignition (CDI) for controlling the spark timing and intensity of spark. The throttle position sensor provides input signal to CDI.
In another embodiment of the present invention the processing means is an Electronic Control Unit (ECU). The throttle position sensor provide signal to ECU.
In still another embodiment of the present invention the sensor assembly is configured to provide digital or linear output signals. Digital output of the throttle position sensor assembly TPS is used in vehicles with capacitive discharge ignition (CDI) unit and Linear/ ratio metric output of the throttle position sensor assembly is used in vehicles with electronic control unit (ECU) or Electric vehicles.
In yet another embodiment of the present invention wherein the sensor assembly is configured to provide one first and plurality of the second output signal indicative of position of the throttle corresponding to the one first and plurality of the second positions of the magnet.
In a further embodiment of the present invention the capacitive discharge ignition (CDI) unit is coupled to a spark plug through a high tension coil.
In a further embodiment of the present invention in 0 to 38° rotation of the throttle pipe the magnet moves closer to the sensor assembly and after 38° rotation the magnet moves away from the sensor assembly.
In one more embodiment of the present invention in 0 to 55° rotation of the throttle pipe the magnet moves closer to the sensor assembly and then in return 55° to 0 the magnet
moves away from the sensor assembly.
The present invention is described with reference to the figures and specific embodiments; this description is not meant to be construed in a limiting sense. Various alternate embodiments of the invention will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such alternative embodiments form part of the present invention.
Figure 4 illustrates the basic mechanism of the throttle position sensing system (1) of the present invention. The throttle position sensing system of the present invention comprises a sensor assembly (2) and a magnet (3). The sensor assembly (2) is mounted inside the control switch of the right hand (RH) handle bar of the two wheeled vehicle. The magnet (3) is also mounted inside the control switch and coupled to the throttle pipe so that with the rotation of the throttle pipe the magnet (3) moves closer to or away from the sensor assembly (2). The throttle pipe of the two wheeled vehicles is connected to throttle and with the rotation of the throttle pipe the throttle rotates from 0 to 90°. The rotation of the throttle controls the intake of the air/fuel mixture. The sensor assembly (2) comprises a Hall Effect transducer or sensor mounted with a printed circuit board. With rotation of throttle pipe the magnet (3) moves from at least one first position to plurality of second positions. The number of second position can be decided based on the requirements. For example for 0 to 55° rotation of the throttle pipe the there can be 9 second positions with an interval of 5°. As the magnet (3) moves closer to the sensor assembly (2) and the sensor assembly (2) generates signals indicative of the position of the throttle. The output signals of the sensor assembly (2) communicated to the processing means (4) as input. The processing means (4) processes the signals of the sensor assembly (2) and then generates signal for achieving the variable spark timing. The processing means (4) can be selected from a group comprising but not limited to capacitive discharge ignition (CDI) unit (5), Electronic Control Unit (ECU) (6) or any other suitable processing means. The processing means (4) can be a separate processing unit or it can be integrated with the capacitive discharge ignition (CDI) unit (5) or Electronic Control Unit (ECU) (6).
One of the advantages of the throttle position sensing system of the present invention is that the sensor assembly can generate digital as well as linear output in the range of 0 to 5 volts. Therefore, the throttle position sensing system of the present invention is workable in different kind of automobiles such as carburetor with CDI or throttle body with ECU system or electrical/battery operated automobiles.
The Non contact throttle position sensing system of the present invention can also be used in battery operated vehicle or electric vehicle. In case of electric vehicle the output signal of the sensor assembly can be configured to indicate the speed desirable by the rider. Therefore, the output signals of the sensor assembly can be transmitted to the processor which can generate appropriate signals to battery and motor for controlling the speed of the vehicle. In case of electric vehicle the throttle position sensor assembly can be configured to provide linear (ratio metric) output. In this type of throttle position sensor, linear Hall Effect IC and a sector magnet are used in construction. The out put is ratio metric and protected against short circuit.
Figure 5 illustrates a simplified block diagram of the throttle position sensing system with the capacitive discharge ignition (CDI) unit according to an embodiment of the present invention. As can be noticed from figure 4, the throttle position sensing system (1) comprises a sensor assembly (2) and magnet (3). The sensor assembly (2) can be mounted on the handle bar of the two or three wheeled vehicles. Said sensor assembly (2) can be integrated with the right hand handle bar switching module. The magnet (3) is mounted on the throttle pipe so that with the rotation of the throttle pipe the magnet (3) moves closer or away from the sensor assembly (2). The throttle pipe of the two wheeled vehicles is connected to the throttle by a cable so that with the throttle pipe the throttle does angular rotation which changes the amount of fuel air mixture intake. The sensor assembly (2) comprises Hall Effect transducer. As the magnet (3) moves closer or away from the sensor assembly (2) the flux linkage between the magnet (3) and sensor assembly (2) changes and the sensor assembly generates plurality of signals indicative of position of throttle. The output signal of the sensor assembly (2) is coupled to the capacitive discharge ignition (CDI) unit through a processing unit which processes the
signal communicated by the sensor assembly and determines variable timing intensity of spark. The processing unit (not shown in figure) then generates signal to CDI (5) for controlled spark timing and intensity of spark for ignition. The processing unit is coupled to a capacitive discharge ignition (CDI) unit. Said processing unit can be a separate unit or it can be integrated with the capacitive discharge ignition (CDI) unit (5). The capacitive discharge ignition (CDI) unit is coupled to a spark plug (7) through a high tension coil (8). Based on the signals provided by the processing unit the capacitive discharge ignition (CDI) unit (5) discharges the energy stored in the CDI (5) and release high voltage pulse via a step up transformer to spark plug for igniting the fuel mixture. The capacitive discharge ignition (CDI) unit is connected with a magneto (9) of the automobile for charging of the capacitor of the capacitive discharge ignition (CDI) unit (5).
Since the sensor assembly and the magnet is integrated with the right hand handle bar of the two & three wheeled vehicle, therefore, the throttle position sensing system of the present invention is economical. Moreover, the throttle position sensing system is accurately measure the position of the throttle and therefore, with the system of the present invention the variable timing in spark can be achieved in a better way.
Figure 6(a) illustrates a circuit diagram of Hall Effect based sensor assembly for throttle position sensing system of the present invention. Figure 6(a) also shows output wave form of the sensor assembly which is communicated to the capacitive discharge ignition (CDI) unit as input signals. Figure 6(a) also provides exemplary illustrations of the output wave form of the sensor assembly (or the input wave form to the capacitive CDI unit) when magnet is closer to the sensor assembly and when it is not present or away from the sensor assembly.
Figure 6(b) illustrates the variation of voltage output from the sensor assembly with the rotation of throttle pipe from 0 to 50° and then in return stroke i.e. from 50° to 0°. As can be noticed from figure 6(b) that for 0 to 50° rotation of the throttle pipe the magnet moves closer to the Hall sensor therefore, the output voltage increases. Similarly, for 50° to 0°
rotation of the throttle pipe the magnet moves away from the Hall sensor, therefore, the output voltage decreases.
In an embodiment of the present invention the output of the throttle position sensor can be linear / ratio metric, which can be used in vehicle for accurate control of spark timing and intensity.
Figure 7(a) illustrates control switch of the right hand (RH) handle bar (10) of the two wheeled vehicle integrated with the sensor assembly (2) of the throttle position sensing system of the present invention. As can be observed from figure 7(a) the sensor assembly is integrated with the right hand (RH) handle bar of the two wheeled vehicles (scooter, motorcycle etc.). The Hall sensor (11) with a printed circuit board is suitably mounted inside the control switch of the right hand (RH) handle bar of the vehicle. The right hand (RH) handle bar (10) is connected to the throttle pipe (12) of the automobile. The magnet (3) and the Hall sensor (11) is placed inside the control switch of the right hand (RH) handle bar (10) (for example inside an upper case (13) and a lower case (14) of the control switch as shown in figure 7) such that with the movement or rotation of the throttle pipe (12) the magnet (3) moves closer to or away from the Hall sensor (11). In an embodiment of the present invention the magnet (3) is placed in such way that due to the rotation of the throttle pipe (12) the magnet (3) first moves closer to the Hall sensor (11) for 0 to 38° rotation of the throttle and then moves away from the Hall sensor for 38° onwards rotation of the throttle. In another embodiment of the present invention, for 0 to 50° rotation of the throttle pipe (12) the magnet (3) moves closer to the Hall sensor (11) and in the return stroke i.e. from 50° to 0° rotation the magnet (3) moves away from the Hall sensor (11). The rotation of the throttle is controlled by the throttle pipe (12) which is movably coupled to the right hand (RH) handle bar (10) of the two wheeled vehicle. As the magnet (3) moves closer or away from the Hall sensor (11), the output of the Hall sensor (11) varies. This output of the Hall sensor (11) which varies with the throttle position is then communicated to the capacitive discharge ignition (CDI) unit for achieving the variable timing in spark. By integrating the sensor assembly with the right hand (RH) handle bar of the vehicle, accurate measurement of the throttle position can be
done. Therefore, the signals provided by the Hall sensor to the capacitive discharge ignition (CDI) unit accurately indicate the position of the throttle which results in better control of the spark timing and intensity of spark to ignition.
Figure 7(b) illustrates solid body sectional view of the sensor assembly integrated with the right hand (RH) handle bar of the two wheeled vehicle according to an embodiment of the present invention. As can be noticed from figure 7(b), the sensor assembly of throttle position sensing system is based on a non-contact mechanism. The non-contact mechanism provides longer life to the throttle position sensing system.
Figure 8 shows the modified control switch in the right hand (RH) handle bar for mounting the sensor assembly and magnet of the throttle position sensing system of the present invention. Different views of the right hand control switch for the throttle sensing system of the present invention are shown in figure 9.
Figure 10 illustrates a proto-trial of control switch for mounting the throttle position sensing system according to the present invention.
The control switch for the throttle position sensing system is designed with following considerations:
(a) High reliability up to 1 million operations
(b) No contact wear and tear
(c) No contact arching
(d) Small in size
Some of the advantages of the present invention are as follows:
(a) Increase in product reliability of vehicle from 2 years to 5 years minimum.
(b) Throttle operations are smooth and easy to use.
(c) Switch can be effectively sealed and the switch can be protected from corrosion and
dust.
(d) Due to the use of electronic parts, more features can be achieved in vehicles.
(e) Safety of vehicles can be enhanced due to the better control. (g) Integration of IPS with RH switch will save cost.

We Claim:
1. A throttle position sensing system (1) for the use in two or three wheeled vehicles with a
handle bar (10) coupled to a throttle pipe (12), said system comprising:
a sensor assembly (2) having a Hall Effect transducer (11) located on a printed circuit
board (PCB) inside a control switch mounted on the handle bar (10);
a magnet (3) located inside the control switch; said magnet (3) is mounted on the throttle
pipe (12) such that the magnet (3) is movable from one first position to plurality of
second positions with the movement of the throttle pipe (12);
a processing means (4) configured to receive input from the sensor assembly (2) and
provide signal for controlling the spark timing and intensity of spark.
2. The system as claimed in claim 1, wherein the processing means (4) is coupled to a
capacitive discharge ignition (CDI) unit (5) for controlling the spark timing and intensity
of spark.
3. The system as claimed in claim 1, wherein the processing means (4) is an Electronic
Control Unit (ECU) (6).
4. The system as claimed in any one of the preceding claims, wherein the sensor assembly
(2) is configured to provide digital or linear output signals.
5. The system as claimed in any one of the preceding claims, wherein the sensor assembly
(2) is configured to provide one first and plurality of the second output signals indicative
of position of the throttle corresponding to the one first and plurality of the second
positions of the magnet.
6. The system as claimed in any one of the preceding claims, wherein the capacitive
discharge ignition unit (CDI) (5) is coupled to a spark plug (7) through a high tension coil
(8).
7. The system as claimed in claims 1 to 4, wherein in 0 to 38° rotation of the throttle pipe
(12) the magnet (3) moves closer to the sensor assembly (2) and after 38° rotation the
magnet (3) moves away from the sensor assembly (2).
8. The system as claimed in claims 1 to 4, wherein in 0 to 50° rotation of the throttle pipe
(12) the magnet (3) moves closer to the sensor assembly (2) and then in return 50° to 0
the magnet (3) moves away from the sensor assembly (2).
9. A throttle position sensing system substantially as herein described with reference to the
accompanying drawings.