Field of invention:
The present invention relates to handlebar switch unit of a motorcycle, particularly,
the present invention relates to left hand (LH) & right hand (RH) handlebar switch
unit with a multiplexing unit for providing multiplexing of plurality of switch
elements thereby reducing wires in the wiring harness providing electrical
connections between the LH or RH switch modules with electronic control module of
the motorcycle.
Background of the Invention:
Motorcycles are provided with plurality of handle bar switch modules mounted on LH
or RH switch units for operating a variety of electrical accessories to perform
different hnctions such as 'High beam', 'Pass', 'Left Blinker', 'Right Blinker', Horn,
'Engine-Kill', 'Main(-)', 'Main(+)', 'Engine-Start'. Each of these afore-mentioned
functions require plurality of switch modules and their actuation to different switch
positions; moreover, there are other switch modules which are required to be provided
in some of the motor cycles include 'hazard switch' 'shifter up and down', mode
switch, music control switch, seat open switch, fog lamp switch etc. Some of these
switch modules form left hand (LH) switch unit and the other switch modules form a
right hand (RH) switch unit. As shown in Figure 1, frequently used switch modules
such as 'Dimmer with Pass -switch', 'Blinker-switch' and 'Horn-switch' form part of
the LH handlebar switch unit module and others switch like 'Engine (E)-Start-switch',
'Engine (E)-Kill-switch' and 'Main-switch' form part of the RH handle bar switch
module. As shown in Figure 1 the RH and LH switch units are connected with
electronic control module and the said electronic control module is connected with
vehicle power source such as magneto or RR unit or battery, Vehicle sensors such as
Neutral, RPM etc. and vehicle loads (i.e. electrical accessories) such as blinker lamps,
head light lamp, parking lamp, horn, engine starter, relay, CDI etc.
The switch module comprises a user operable switch button with one or more switch
element for generating signal in the form of electrical pulse. The switch element may
be of a contact-type switch element or a non-contact type switch element. Actuation
of the switch button actuates the switch element so as to generate or provide a signal
in the form electrical pulses which is transmitted via wiring harness to the Electronic
Control Unit (ECU) of the vehicle. According to the received signals, the ECU
generates an output signal to operate the corresponding electrical accessory. Figure 2
illustrates a block diagram showing wiring harness providing electrical connections
between the ECU and the LH and RH switch modules.
As can be clearly understood that each of the LH and RH switch unit comprises
plurality of switch modules including plurality of switch elements and this require that
the wiring harness to include a plurality of wires for transmitting the switching signals
from the plurality of switch elements (in the LH or RH switch unit) to the ECU.
Further, due to the plurality of wires in the wiring harness, the Control module or
ECU require plurality of input pins for receiving the switching or input signals. It has
been always desired to reduce the number of input pins to reduce the size of the ECU
thereby reducing the cost of the same.
For reducing the number of input pins in the ECU, number of wires in the wiring
harness is required to be reduced. Conventionally, standard multiplexing system
utilizing CAN (Controller area network) or LIN (Local Interconnect Network) based
unit being used as shown in Figure 3, which detects the operation/actuation of
different switch elements in (LH or RH switch unit) provides a corresponding signals
through less number of wires to the ECU. As shown in Figure 3, CAN and LIN units
are placed outside the handlebar switch unit and because of large size of CAN and
LIN unit, it is not possible to integrate or accommodate the same within the switch
unit. Since, CAN and LIN unit can not be integrated within the switch unit, number of
wires coming out from switch remains the same. Further, the system utilizing CAN or
LIN unit are costly and includes large number of components.
Therefore, there exists a need to develop a switch unit which includes a multiplexing
feature for providing multiplexing of switches thereby reducing the number wires
coming out of the switch module.
Objects of the present invention:
Main object of the present invention is to reduce electric wires in wiring harness
which connects the handlebar switch unit with the Electronic control unit (ECU) of
the motorcycle.
Another object of the present invention is to provide a handlebar switch unit
comprising switch elements integrated with a multiplexing unit providing
multiplexing of switch modules or switch elements of the switch unit of the
motorcycle.
Summary of invention:
Accordingly, the present invention provides a handlebar switch unit for operating one
or more accessories of a motorcycle, the switch unit is electrically connected with a
power supply source and an electronic control unit (ECU) disposed in the motorcycle,
said switch unit comprising:
(a) plurality of switch elements which upon actuation provides electrical pulses to
the ECU;
(b) a multiplexing unit; and
(c) a casing for accommodating the said plurality of switch elements and the
multiplexing unit;
the multiplexing unit comprises:
(i) plurality of impedance units,
(ii) an Input comprising plurality of input ports electrically connected with
the plurality of the switch elements and plurality of the impedance
units thereby introducing an impedance in series with the each of the
switch elements;
(iii) an output comprising plurality of output ports being electrically
connected with the ECU;
the impedance units are divided in one or more groups, and each group is
electrical connected with one of the plurality of the output ports and each of
the impedance units in a group has an impedance value different from
impedance value of other impedance units in the same group.
In an embodiment of the present invention, the number of switch elements and the
number of input ports is 'm', and the number of output ports is 'n', wherein m>n>l.
In another embodiment of the present invention, the impedance units are divided in
two groups, a first group and a second group in which the first group of the
impedance units are electrically connected with one of the output port of the
multiplexing unit by a single electrical connector and the second group of the
impedance units are electrically connected with another output port of the
multiplexing unit by a single electrical connector.
In still another embodiment of the present invention, the impedance units are divided
in the said groups based on mechanical or ergonomical feasibility, or combinations
thereof, relating to operation of switch elements.
In yet another embodiment of the present invention, the multiplexing unit comprises
one or more ground ports for connecting the switch elements and the ECU with the
ground.
In a further embodiment of the present invention, the casing is mounted on Left hand
(LH) side of handlebar of the motorcycle.
In a krther more embodiment of the present invention, the switch elements are
configured, upon actuation, to perform the functions selected from 'High beam',
'Pass', 'Left Blinker', 'Right Blinker', Horn.
In another embodiment of the present invention, the impedance units connected in
series with the switch elements that are configured to perform functions of 'Left
Blinker', 'Right Blinker' and 'Horn' are grouped in the first group being connected
with the ECU by a single electrical connector through the common output port, and
the impedance units connected in series with the switch elements that are configured
to perform functions of 'High beam' and 'Pass' are grouped in the second grouped
being connected with the ECU by a single electrical connector through the common
output port.
In still another embodiment of the present invention, the casing accommodating the
plurality of switch elements is mounted on Right hand (RI-I) side of handlebar of the
motorcycle.
In yet another embodiment of the present invention, the switch elements are
configured, upon actuation, to perform the functions selected from 'Engine-Kill',
'Main(-)', 'Main(+)' and ' Engine-Start' .
In a further embodiment of the present invention, the impedance units connected in
series with the switch elements that are configured to perform functions of Engine-
Kill' and 'Engine-Start' are grouped in the first grouped being connected with the
ECU by a single electrical connector through the common output port, and the
impedance units connected in series with the switch elements that are configured to
perform functions of Main(-)' and 'Main(+)' are grouped in the second group being
connected with the ECU by a single electrical connector through the common output
port.
In a further more embodiment of the present invention, the impedance units is
selected from resistor, inductor, series or parallel cocnections of resistors, series or
parallel connections of inductors, or a combination thereof
In an embodiment of the present invention, each of the impedance units comprises
resistors which is electrically connected in series with a switch element via the input
port.
In another embodiment of the present invention, the each of the resistor has ohmic
value different from the ohmic value of other resistors of the multiplexing unit.
In one more embodiment of the present invention, the multiplexing unit comprises a
printed circuit board (PCB) and the plurality of impedance units being disposed on the
said PCB.
Brief description of figures:
Figure 1 exemplary illustration showing different switches of LH and RH handle bar
switch unit, battery and vehicle loads (i.e. electrical accessories such as blinker, head
light, horn etc. connected with control module) connected with the ECU.
Figure 2 illustrates a block diagram showing wiring harness providing electrical
connections between the ECU and the LH and RH switch unit.
6
Figure 3 illustrates a block diagram showing wiring harness providing electrical
connections between the handlebar switch unit and the ECU with standard
multiplexing system utilizing CAN or LIN unit.
Figure 4 shows a block diagram illustrating a handle bar switch unit with multiplexing
unit according to an embodiment of the present invention.
Figure 5 shows a LH handlebar switch unit integrated with multiplexing unit
according to an embodiment of the present invention.
Figure 6 shows a RH handlebar switch unit integrated with multiplexing unit
according to an embodiment of the present invention.
Figure 7 illustrates a block diagram showing reduced number of wires required in
wiring harness for providing electrical connections between multiplexed handlebar
switch unit and the ECU according to an embodiment of the present invention.
Figure 8 shows a graph indicating the fluctuation of voltage for different switch
elements or switch position.
Description of the present invention:
Accordingly, the present invention provides a handle bar switch unit for operating one
or more accessories of a motor cycle. The switch unit of the present invention
comprises switch elements integrated with a multiplexing unit for providing
multiplexing of switch elements thereby reducing number of wires in wiring harness
which electrically connects the handle bar switch unit with the Electronic Control
Unit (ECU) of the motorcycle.
As described in the previous paragraphs, the handlebar switch unit includes a variety
of switch modules and each switch module includes one or more switch elements. The
switch module may be hinge type, rocker or push type switch module. Further, the
switch module can be classified into the following three categories on the basis of the
signal generated by one or more switch element of the switch module,
(a) Pulse type module (for Push type, Swing type, etc ...
(b) Continuous type module (for Hinge, Push type, etc.. .)
(c) Continuous Latch type module (for Rocker, Slide, rotary type, etc.. .)
According to an embodiment of the present invention, the handlebar switch unit
comprises plurality of low ampere switch elements (contact type or non-contact type)
which upon actuation, generates or provides signal in the form of electrical pulses.
The switch elements are connected to an Electronic Control Unit (ECU) mounted on
the motorcycle by a wiring harness comprises two or more wires. For reducing the
number of wires in the wiring harness, signals generated by two or more switch
elements can be multiplexed together and transmitted to the ECU through a common
wire. For this purpose, the present invention provides a multiplexing unit which may
be disposed inside the casing of the handle bar switch unit for multiplexing signals
generated by switch elements. In an embodiment, the multiplexing unit comprises a
circuit being configured for providing voltage multiplexing of the switch elements. In
an embodiment of the present invention, signals generated by the switch elements are
supplied to the electronic control unit via multiplexing unit. In other words, signals
generated by the switch elements pass through the multiplexing unit. The electrical
connection between the switch elements and the multiplexing unit may be
implemented by flexible connectors or by rigid wires or terminals.
Figure 4 shows a block diagram illustrating handle bar switch unit according to an
embodiment of the present invention. The switch unit comprising plurality of switch
elements and a multiplexing unit are accommodated inside a casing (not shown in
figure). The multiplexing unit is configured to provide voltage multiplexing of the
signals generated or provided by the said plurality of switch elements.
Referring to Figure 4, the multiplexing unit comprises an input (I) for receiving signal
from 'm' number of switch elements (S1, S2, . . . . . .Sm) and an output (0) for providing
an output signal to the Electronic Control Unit (ECU) for operating the load. The
input comprising 'my number of input ports (I,, 12, . . . . . .Im) each of which electrically
connected with a switch element. As the input ports are same in numbers vis-A-vis the
number of switch elements, one input port can be electrically connected with one
switch element. The output (0) comprising 'n' number of output ports (01, 02,
...... 0,). As can be observed from Figure 4, the number of output ports (01, 02,
...... On) is lesser than the number of input ports (11, 12, ...... Im) i.e. 1 < n < m
according to an embodiment of the present invention. The multiplexing unit
comprising 'm' number of impedance unit and each of the impedance unit is
8
electrically connected in series with one input port. As the number of impedance unit
is same vis-a-vis number of input ports, one impedance unit may be electrically
connected with one input port so that the electrical signal generated by each switch
elements passes through the respective impedance unit. In other words, each of the
impedance unit is electrically connected in series with one switch element thereby
introducing an impedance in series with each of the switch elements.
In the 'm' number of impedance units, each of the impedance unit has different value
of impedance as compared to the other impedance units so as to introduce a different
value of impedance in series with each of the switch element. Since, each of the
impedance unit introduces different values of impedance in series with each of the
switch elements, the value of signal generated by each of the switch element differs
and depends on the value of impedance connected in series with the said switch
element.
In an embodiment of the present invention, the switch elements and respective
impedance units connected thereto, are grouped or divided in one or more groups with
each group comprising one or more switch elements and respective impedance units
connected with the said one or more switch elements. All the impedance units in one
group may be connected by one common output port. In other words, all the signals
generated and passing through impedance units in one group may be obtained through
one common output port and supplied to the ECU by a single electrical connector
such as wire.
Each impedance unit includes a means for introducing impedance which may be
selected from resistor, inductor, series or parallel connections of resistors, series or
parallel connections of inductors, or a combination thereof In an embodiment, each
of the impedance unit is one group has different impedance value as compared to
impedance value of other impedance units in the same group. As different value of the
impedance is connected in series with the switch elements, the switch elements
generates voltage signals in different voltage range.
The impedance units and their respective switch elements may be divided in said one
or more groups based mechanical or ergonomic feasibility, or combinations thereof,
relating to operation of switch elements.
The multiplexing unit further comprises at least one ground port for electrically
connecting the switch elements and the ECU with ground terminal.
As can be clearly understood that, if all the impedance units of the switch unit are
kept in the single group, at least two electrical connectors such as wires will be
required in the wiring harness as one electrical connector or wire will be used for
connecting the switch elements with the ground so that the other or second wire is
available for electrically connecting the switch elements with the ECU via the
multiplexing unit.
The handlebar switch unit of the present invention may be a right hand (RH)
handlebar switch unit or a left hand (LH) handlebar switch unit. In case of RH
handlebar switch unit the casing accommodating the switch elements and the
multiplexing unit may be mounted on the right hand side of handlebar of the
motorcycle. In case of LH handlebar switch unit the casing accommodating the switch
elements and the multiplexing unit may be mounted on the right hand side of
handlebar of the motorcycle.
Figure 5 shows a left hand (LH) handlebar switch unit according to an embodiment of
the present invention. Referring to Figure 5, the LH handlebar switch unit comprises
switch module for performing following five functions namely 'High Beam', 'Pass',
'Left Blinker', 'Right Blinker' and 'Horn' with one default function (i.e. low beam
when high beam switch is off). As it can be clearly understood, the aforementioned
fbnctions can be performed by five separate switch elements. Further, two or more
functions can be assigned by a single switch module comprising two switch elements.
For example, 'Blinker switch module' comprises two switch elements in which one
switch element is provided for 'Right Blinker' function i.e. when the blinker switch
module is actuated from 'OFF' position to the 'Right Blinker' position and second
switch element is provided for the "Left Blinker" function i.e. when the blinker switch
module is actuated fiom 'OFF' position to 'Left Blinker' position. Therefore, five
switch elements may be are required in LH handlebar switch unit.
According to an embodiment of the present invention, the switch elements are low
ampere contact type switch elements including moving and fixed contacts. The
following table (Table 1) describes the type of contacts are to be made between the
moving and fixed contacts by the contact-type switch elements for performing the
above functions.
Table 1
As shown in figure 5, the multiplexing unit comprises five impedance units and each
of the five impedance unit comprises a resistor (R~~sRs,~ i~hbearRn,R BIR, LBIa, nd h o r n ) .
Each of the five switch elements is electrically connected with one resistor in series
and each of the resistors has different ohmic value so that the signal generated by each
of the switch element have a different value so that each of the above mentioned
function may be assigned with a different and mutually exclusive voltage ranges that
are detected at the ECU. As can be clearly observed that each of the five switch
elements are connected with an input port provided at the input of the multiplexing
unit and therefore, for this purpose, at least five input ports are disposed at the input of
the multiplexing unit. Each one of the five input ports is electrically connected with
one impedance unit (i.e. resistor). As shown in figure 5, the switch elements in the LH
handle bar switch unit is divided in two groups i.e. a first group and a second group.
The first group of switch elements comprises three switch elements of 'Left Blinker',
'Right Blinker' and 'Horn' functions. The second group of the switch elements
comprises two elements of 'High Beam' and 'Pass' functions. Accordingly, the
resistors connected in series are divided in two groups i.e. first group and a second
group corresponding to the first group of elements and second group of elements. In
11
Sr. No.
1
2
3
4
5
Switch Function
High Beam
Pass
Left Winker
Right Winker
Horn
Contact Type
Continue (latch)
Continue
Pulse
Pulse
Continue
Remarks
Low Beam is Default
As can be clearly understood from figure 5, the first group of resistors comprising
three resistors each one of which is connected in series with the three elements of
'Left Blinker', 'Right Blinker' and 'Horn' functions and the second group of resistors
cmprises two resistors each one of which is connected with two elements of 'High
Beam' and 'Pass' functions. In other words, the resistors RRB,,R LBIa, nd R~oma nd the
switch elements of 'Left Blinker', 'Right Blinker' and 'Horn' functions are kept in
first group. Similarly, the resistors Rpas, and R ~ ~ ~ hanbd~ th~em sw itch elements of
'High Beam' and 'Pass' functions are kept in second group.
Referring to figure 5, all the resistors in one group is connected to one common output
port. Therefore, the multiplexing unit is provided with two output ports disposed at
the output of the multiplexing unit and in that, one output port is connected with the
three resistors of first group (i.e. RRBI, h B I ,a nd horannd th)e other output port is
connected with two resistors of the second group (i.e. RPassa nd RHighbeamO). ne or
more ground ports can be disposed at the input and output for connecting the switch
elements and the ECU with the ground. The two output ports are electrically
connected with the ECU through a wiring harness. As can be clearly noticed from
Figure 5, the number of wires in the wiring harness depends on the number of output
ports and the number of output ports depends upon number of groups in which the
switch elements or the impedance units have been divided.
The following paragraphs describe the method for identifying the groups of switch
elements and the corresponding groups of resistors according to an embodiment of the
present invention.
As per the requirements, the user can actuate two or more switch elements to perform
two or more functions simultaneously. For example, the 'High Beam' and 'Horn'
function may be performed simultaneously or 'Blinker' (Right or Left) function and
'High Beam' may be performed simultaneously etc. Therefore, apart from individual
functions, all possible combinations of functions are required to be determined for
identifying the groups of switch elements or their corresponding resistors (i.e. the
resistors connected in series with the said switch elements).
In case of two wheeler or a motorcycle, the rider has to focus on riding and handling
the vehicle for example at the time of steer. As a result, it is preferable to use the
thumb operating the handle bar switch module as the rider has to control the vehicle
simultaneously. For example, in case of two-wheeler or motorcycle, the switch
modules on the front sides are constructed so as to be operable with thumb in most
easy and safe way. Further, if the switches are of pulse type, then it is impossible to
operate two switches at same time.
In order to identify the all possible combinations of groups of switch elements or of
functions associated with the switch elements, a truth table may be made.
Considering a wiring harness with two wires connecting the LH handle bar switch
unit with the ECU, only one wire (LH-Vout) will be available for detecting signals
generated or provided by actuation of the switch elements as the other wire will be
required for connecting the switch elements and the ECU with the ground. In other
words, all the five switch elements and their corresponding impedance units (i.e.
resistors) are kept in one group i.e. all the resistors are connected with one common
output port of the multiplexing unit. In the Two-wire wiring harness the output of all
the switch elements is transmitted to the ECU through one wire i.e. (LH-Vout). The
following Table-2 shows a truth table for identifying all possible combinations of the
'functions' which can be possible in Two-wire wiring harness.
Table 2
I Truth Table (2 wire): All Possible Combination I
Where,
'0' represent: 'OFF" position of Low Ampere Switch
'1' represent: 'ON" position of Low Ampere Switch
As can be clearly understood from the above Table 2, the combinations of the
functions categorized and marked as invalid on the basis of following three criteria(
a) Mechanically not possible- this combination of functions is not possible because
of constructional limitations of the switch module. For example, due to the
construction of 'Blinker' switch module, it is not possible to perform 'Right Blinker'
and 'Left Blinker' function simultaneously. Similarly, performing 'High Beam' and
'Pass' functions is not possible due to the mechanical construction of the switch
module performing said functions.
(b) Ergonomically not possible-this combination of functions is ergonomically not
possible and therefore, marked as invalid. For example, performing 'Horn' function
with 'Right' or 'Left' blinker function since these combinations are ergonomically not
possible for the rider (or user) of the motorcycle.
(c) Mechanically and Ergonomically not possible- this combination of functions
which are not possible due to constructional as well as ergonomic considerations as
described in (a) and (b).
Further, as can be noticed from Table 2, there are total 32 combinations of functions
possible in LH handle bar switch unit assembly. Out of the 32 possible combinations
only 9 are valid combinations. Whereas, number of invalid combinations are 23 in
which 9 are ergonomically invalid and 14 are mechanically invalid combinations.
As described in previous paragraph, with two-wire wiring harness only one wire is
available for detecting actuation of the switch. In other words, output from the LH
handle bar switch unit is taken out by a single wire in respect of all possible
combinations of the functions. Normally, 0-5V is available in the said single wire of
the wiring harness for detecting the actuation of the switch elements and all the valid
combinations of the functions is required to be assigned mutually exclusive voltage
range so that the same can be detected by the ECU. In other words, the voltage range
of 0-5V is required to be divided into at least 9 different ranges so that the same can
be assigned to 9 valid combinations of functions.
As can be clearly understood, the voltage range which is available to be divided
among the functions or combinations of functions is small; and also, the LH handlebar
switch unit may include more switch modules such as 'Hazard' Switch, 'Shifter-Up'
and 'Shifter-Down' switch and 'Mode' switch etc. Therefore, though division of
voltage range is possible but it is difficult to divide a small voltage range of 0-5V
15
among the large number of functions. Also, when failure is detected, the finctions of
all the switches will be lost altogether.
Considering robustness of the switch module, the present invention provides dividing
the above combination into two different groups according to an embodiment and in
which each of the said group is connected with separate wires through the two output
ports disposed at the output of the multiplexing unit. Referring to figure 5, the wiring
harness include at least three wires out of which two wires namely 'LH-Voutl' and
'LH-Vout2' are available for detecting actuations of switch element in each of the
said group. Third wire will be connected with the ground.
As described in previous paragraph, if failure is detected in either group, all the
hnctions associated with the elements will be lost in the said failed group.
In an embodiment of the present invention, all combinations which are 'mechanically
not possible' may be grouped together in one group so that working of the LH switch
unit is more robust. According to an embodiment of the present invention, the
following groups can be made in LH handlebar switch unit,
(i) 'High Beam' and 'Pass' function in one group for transmitting the signals fiom
corresponding switch elements via a common wire i.e. LH-Voutl
(ii) 'Left Blinker', 'Right Blinker' and 'Horn' functions in one group for transmitting
the signals from corresponding switch elements via a common wire i.e. LH-Vout2
The following truth table (Table 3) may be formed based on the above groups (i) and
(ii) and three-wire wiring harness connecting the said groups (i) and (ii) of the LH
switch unit with the ECU.
Table 3
Where,
'0' represent: 'OFF" position of Low Ampere Switch
' 1' represent: 'ON" position of Low Ampere Switch
As can be clearly noticed from above Table 3, there are total 12 combinations of the
functions are possible in LH handlebar switch unit with three-wire wiring harness.
Out of the 12 combinations, only 7 are valid. Whereas, 5 combinations of hnctions
are mechanically or ergonomically invalid which may not require any sensing or
detection. As described in previous paragraphs, two wires i.e. LH-Voutl and
LH-Vout. are available for detecting voltage and in each wire 0-5V is available. In
other words, 0-5V can be divided among functions detected on LH-Voutl and
similarly, 0-5V can be divided among functions detected on LH-Vout2.
Referring to figures 5 and 7, a three-wire wiring harness connects the LH handle bar
unit with the ECU. In the LH handle bar unit, the resistors of the multiplexing unit i.e.
Rpass, R~i~hbeamR, RBI,~ B Ian,d R~ornc onnected in series with switch elements or
switch positions respectively which performs 'Pass', 'Highbeam', 'Right Blinker',
'Left Blinker' and 'Horn' function.
As described in previous paragraphs, each of the resistors, at least in one group, has
different ohmic value than the ohmic value of the other resistors in the same group.
For example, in the first group, each of the resistors i.e. R ~ I&,B I, and R~om may
have different ohmic value so that each of switch elements connected with said
resistors (i.e. RRB1,R LBIa, nd R~orn)g enerates or provides different electrical pulses. In
other words, the different voltage is detected at the ECU when the switch elements
connected with such resistors (i.e. Rml, RLBI,a nd R H ~o~f )di fferent value are
actuated. Accordingly, ECU may be configured to detect actuation of a particular
switch element (i.e. Horn, Right blinker or Left blinker) or actuation of possible
combinations thereof based on the voltage detected at input of the ECU. Similarly,
each of the resistors in the second group i.e. ha, and RHighbeam, may have different
ohmic value so that each of switch elements connected with said resistors (i.e. RPass
and RHighbeamge) nerates or provides different electrical pulses. In other words, the
different voltage is detected at the ECU when the switch elements connected with
such resistors (i.e. R~as, and RHighbeam) of different value are actuated. Accordingly,
ECU may be configured to detect actuation of a particular switch element (i.e. Pass
and High Beam) or actuation of possible combinations thereof based on the voltage
detected at input of the ECU.
Similar to LH handle bar switch unit, the switch elements of the RH handle bar switch
unit can be multiplexed according to an embodiment of the present invention. Figure
6 shows RH handlebar switch unit according to an embodiment of the present
invention.
Normally, there are four Low Ampere switches in the RH handlebar switch unit (EKill,
Main -, Main + and E-Start) with one default condition (i.e. Engine Run when EKill
switch is off).
The following table (Table 4) describes the type of contacts are to be made between
the moving and fixed contacts by the contact-type switch elements for performing the
above functions.
Table 4
Considering a wiring harness with two wires connecting the RH handlebar switch unit
with the ECU one wire (RH-Vout) is available for detecting actuation or activation of
switch element. As described in previous paragraphs with reference to LH handlebar
switch unit, a truth table may be formed for RH handlebar switch unit. Accordingly,
the following truth Table 5 may be formed for RH handlebar switch unit,
Sr. No.
1
2
3
4
Table 5
Tmth Tabk (2 wire): A8 Posibk Combinatbn
E-KI~ I Naln I ~ w n + I E-nrc I war I 1
Dome Switch Function
E-Kill
Main - (off, PO & PWHL)
Main + (off, PO & PO+HL)
E-Start
Where,
'0' represent: 'OFF" position of Low Ampere Switch
' 1' represent: 'ON" position of Low Ampere Switch
Further, as can be noticed from Table 5, there are total 16 combinations of functions
possible in LH handle bar switch unit assembly. Out of the 16 possible combinations
Dome Contact
Type
Continue (latch)
Pulse
Pulse
Continue
Remarks
Run Condition is
Default
only 8 are valid combinations. Whereas, number of invalid combinations are 8 in
which 4 are ergonomically invalid and 4 are mechanically invalid combinations.
As only one wire, in two-wire wiring harness, is available for detecting actuation of
the switch. In other words, output from the RH handle bar switch unit is taken out by
a single wire in respect of all possible combinations of the functions. Normally, 0-5V
is available in the said single wire of the wiring harness for detecting the actuation of
the switch elements and all the valid combinations of the functions is required to be
assigned mutually exclusive voltage range so that the same can be detected by the
ECU. In other words, the voltage range of 0-5V is required to be divided into at least
8 different ranges so that the same can be assigned to 8 valid combinations of
functions.
Considering the robustness of the system feature the switch elements and their
corresponding resistor of the impedance unit may be divided in two groups.
Referring to figure 6, the wiring harness include at least three wires out of which two
wires namely 'RH-Voutl' and 'RKVout2' are available for detecting actuations of
switch element in each of the said group. Third wire will be connected with the
ground.
Considering robustness of the system, mechanical not possible combination can be
grouped in one group and may be connected with one wire.
(i) E-Kill and E-Start function in one group (say first group) for transmitting the
signals from corresponding switch elements via a common wire i.e. RXVoutl
(ii) Main - and Main + functions in one group (say second group) for transmitting the
signals from corresponding switch elements via a common wire i.e. LH-Vout2.
The following truth table (Table 6) may be formed based on the above groups (i) and
(ii) and three-wire wiring harness connecting the said groups (i) and (ii) of the RH
switch unit with the ECU.
Table 6
Where,
'0' represent: 'OFF" position of Low Ampere Switch
' 1' represent: 'ON" position of Low Ampere Switch
As can be clearly noticed from above Table 6, there are total 8 combinations of the
functions are possible in RH handlebar switch unit with three-wire wiring harness.
Out of the 8 combinations, only 7 are valid. Whereas, 1 combination of functions are
mechanically or ergonomically invalid which may not require any sensing or
detection. As described in previous paragraphs, two wires i.e. RXVoutl and
RH-Vout 2 are available for detecting voltage and in each wire 0-5V is available. In
other words, 0-5V can be divided among hnctions detected on RKVoutl and
similarly, 0-5V can be divided among functions detected on LH-VouQ.
Referring to figures 6 and 7, a three-wire wiring harness connects the RH handle bar
unit with the ECU. In the RH handle bar unit, resistors of the multiplexing unit i.e.
R ~ ~ i lRl~, a in- , R~ain+ and R~-sta*c onnected in series with switch elements or switch
positions respectively which performs E-Kill, Main -, Main + and E-Start function.
As described in previous paragraphs, each of the resistors, at least in one group, has
different ohmic value than the ohmic value of the other resistors in the same group.
For example, in the first group, each of the resistors i.e. and R ~ - smta~y have
different ohmic value so that each of switch elements connected with said resistors
(i.e. RE-KiIa1n d RE-Startg) enerates or provides different electrical pulses. In other
words, the different voltage is detected at the ECU when the switch elements
connected with such resistors (i.e. RE-K~anI~d RE-start)o f different value are actuated.
Accordingly, ECU. may be configured to detect actuation of a particular switch
element (i.e. E-Kill and E-Start) or actuation of possible combinations thereof based
on the voltage detected at input of the ECU. Similarly, each of the resistors in the
second group i.e. R~ain- and R~ain+, may have different ohmic value so that each of
switch elements connected with said resistors (i.e. R~ai, - and RMain +) generates or
provides different electrical pulses. In other words, the different voltage is detected at
the ECU when the switch elements connected with such resistors (i.e. RMaina-n d RMain
+) of different value are actuated. Accordingly, ECU may be configured to detect
actuation of a particular switch element (i.e. Main - and Main +) or actuation of
possible combinations thereof based on the voltage detected at input of the ECU.
The truth table or the combinations of the switch elements' finctions for electrically
connected by one or more common wires may vary according to the requirement or
type of application of switches. However, all such variations will completely fall with
the scope of the present invention.
Due to practical limitation it is not possible to get same voltage every time because
the voltage sense by electronic control unit (ECU) is not only depend on respective
resistance value but on various other parameters like:
Temperature
Vehicle Voltage (which is highly fluctuated)
Length of wire (Switch to Control Unit)
Contact resistance
Therefore, the ECU may be configured to detect a voltage in a voltage range to
identify activation or actuation of a particular switch element. Figure 8 and Table 7
indicates the fluctuation voltage.
Table 7
Referring to Figure 7, point on the line is ideal voltage point indicates ideal voltage
value detected at the ECU upon actuation of a particular switch element, and the
square shaped point located above the said ideal voltage point indicates higher value
and triangle shaped point located below the said ideal voltage point indicate lowest
possible value of voltage detected at the ECU in respect of actuation of for the said
switch element.
The present invention provides a switch unit in which switch elements are integrated
with a circuit forming a multiplexing unit for voltage multiplexing of the switch
elements in a switch unit which include less number of components and therefore cost
effective. The multiplexing unit may be in the form of a printed circuit board (PCB)
provided with plurality of impednace units disposed on the said PCB. The PCB canbe
accommodated inside the casing of the handlebar switch unit along with the switch
Min.
Voltage
5.000
4.500
4.000
3.500
3.000
2.500
Ideal
Voltage
5.200
4.700
4.200
3.700
3.200
2.700
elements.
Max.
Voltage
5.400
4.900
4.400
3.900
3.400
2.900
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.
We Claim:
1. A handlebar switch unit for operating one or more accessories of a
motorcycle, the switch unit is electrically connected with a power supply
source and an electronic control unit (ECU) disposed in the motorcycle, said
switch unit comprising:
(a) plurality of switch elements which upon actuation provides electrical pulses to
the ECU;
(b) a multiplexing unit; and
(c) a casing for accommodating the said plurality of switch elements and the
multiplexing unit;
the multiplexing unit comprises:
(iv) plurality of impedance units,
(v) an Input comprising plurality of input ports electrically connected with
the plurality of the switch elements and plurality of the impedance
units thereby introducing an impedance in series with the each of the
switch elements;
(vi) an output comprising plurality of output ports being electrically
connected with the ECU;
the impedance units are divided in one or more groups, and each group is
electrical connected with one of the plurality of the output ports and each of
the impedance units in a group has an impedance value different from
impedance value of other impedance units in the same group.
2. A switch unit as claimed in claim 1, wherein the number of switch elements
and the number of input ports is 'my, and the number of output ports is 'n',
wherein m>n> I.
3. A switch unit as claimed in claim 1, wherein the impedance units are divided
in two groups, a first group and a second group in which the first group of the
impedance units are electrically connected with one of the output port of the
multiplexing unit by a single electrical connector and the second group of the
impedance units are electrically connected with another output port of the
multiplexing unit by a single electrical connector.
4. A switch unit as claimed in claims 3, wherein the impedance units are divided
in the said groups based on mechanical or ergonomical feasibility, or
combinations thereof, relating to operation of switch elements.
5. A switch unit as claimed in claim 1, wherein the multiplexing unit comprises
one or more ground ports for connecting the switch elements and the ECU
with the ground.
6. A switch unit as claimed in claim 1, wherein the casing is mounted on Left
hand (LH) side of handlebar of the motorcycle.
7. A switch unit as claimed in claim 7, wherein the switch elements are
configured, upon actuation, to perform the functions selected from 'High
beam', 'Pass', 'Left Blinker', 'Right Blinker', Horn.
8. A switch unit as claimed in claims 1-7, wherein the impedance units
connected in series with the switch elements that are configured to perform
functions of 'Left Blinker', 'Right Blinker' and 'Horn' are grouped in the first
group being connected with the ECU by a single electrical connector through
the common output port, and the impedance units connected in series with the
switch elements that are configured to perform functions of 'High beam' and
'Pass' are grouped in the second grouped being connected with the ECU by a
single electrical connector through the common output port.
9. A switch unit as claimed in claim 1, wherein the casing accommodating the
plurality of switch elements is mounted on Right hand (RH) side of handlebar
of the motorcycle.
10. A switch unit as claimed in claim 9, wherein the switch elements are
configured, upon actuation, to perform the functions selected from 'Engine-
Kill', 'Main(-)', 'Main(+)' and 'Engine-Start'.
11. A switch unit as claimed in claim 10, wherein the impedance units connected
in series with the switch elements that are configured to perform functions of
Engine-Kill' and 'Engine-Start' are grouped in the first grouped being
connected with the ECU by a single electrical connector through the common
output port, and the impedance units connected in series with the switch
elements that are configured to perform functions of Main(-)' and 'Main(+)'
are grouped in the second group being connected with the ECU by a single
electrical connector through the common output port.
12. A switch un'it as claimed in claim 1, wherein the impedance units is selected
from resistor, inductor, series or parallel connections of resistors, series or
parallel connections of inductors, or a combination thereof
13. A switch unit as claimed in claims 8 and 11, wherein each of the impedance
units comprises resistors which is electrically connected in series with a switch
element via the input port.
14. A switch unit as claimed in claims 13, wherein the each of the resistor has
ohmic value different from the ohmic value of other resistors of the
multiplexing unit.
15. A switch unit as claimed in any one of claims 1-14, wherein the multiplexing
unit comprises a printed circuit board (PCB) and the plurality of impedance
units being disposed on the said PCB.