Claims:WE CLAIM:
1. A circuit (100) for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition (102) is turned OFF, the circuit (100) comprising:
a microcontroller (120);
a first relay (110) configured to provide DC power (A) from a battery (130) to the microcontroller (120) when the vehicle ignition (102) is in OFF condition;
a first detection circuit (140) configured to detect ON position of a headlamp switch (150), and to supply a signal to the microcontroller (120) indicating the ON position of the headlamp switch (150);
a second relay (160) configured to provide DC power (A) from the battery (130) to a beam control switch (170), the beam control switch (170) configured to connect a high beam light source or a low beam light source with the DC power (A); and
a second detection circuit (180) configured to detect a position of the beam control switch (170), and to supply a signal to the microcontroller (120) indicating the position of the beam control switch (170); wherein
the microcontroller (120) configured to activate the second relay (160) for the predetermined time if the beam control switch (170) is detected to remain in a high beam position for illuminating the headlamp for the predetermined time after vehicle ignition (102) is turned OFF.
2. The circuit (100) as claimed in claim 1, wherein the microcontroller (120) configured to:
activate the first relay (110) for a predetermined time when vehicle ignition (102) is turned OFF;
determine, based on input received from the first detection circuit (140), position of the headlamp switch (150);
activate the second relay (160), when the headlamp switch (150) is in ON position, thereby allowing the second relay (160) to provide DC power (A) to the beam control switch (170);
determine position of the beam control switch (170) based on input received from the second detection circuit (180); and
keep the second relay (160) activated for the predetermined time if the beam control switch (170) is in a high beam position thereby illuminating the headlamp for the predetermined time after vehicle ignition (102) is turned OFF.

3. The circuit (100) as claimed in claim 1, wherein the microcontroller (120) is further configured to: monitor voltage of the battery (130); and activate the first relay (110) only when the battery (130) voltage is above a threshold voltage.

4. The circuit (100) as claimed in claim 1, wherein the microcontroller (120) is further configured to activate the first relay (110) only when the engine RPM crosses a first predetermined RPM between a last turning ON of the vehicle ignition (102) and turning OFF of the vehicle ignition (102).

5. The circuit (100) as claimed in claim 1, wherein the microcontroller (120) is further configured to activate the first relay (110) only when the engine RPM is below a second predetermined RPM after the vehicle ignition (102) is turned OFF.

6. The circuit (100) as claimed in claim 1, wherein the microcontroller (120) is further configured to: receive a pulsating signal from the second detection circuit (180) when the beam control switch (170) is toggled between a high beam position and a low beam position within a predetermined duration; and increase the predetermined time by a set increment.

7. The circuit (100) as claimed in claim 6, wherein a cycle of toggling within the predetermined duration comprises of the beam control switch (170) being positioned from a high beam position to a low beam position and back to a high beam position.

8. The circuit (100) as claimed in claim 1, comprises an ambient light sensor (190) for providing real time ambient lighting inputs to the microcontroller (120), wherein the microcontroller (120) activates the first relay (110) only when real time ambient lighting inputs correspond to a night condition.

9. The circuit (100) as claimed in claim 1, wherein the predetermined time is 20 seconds.

10. The circuit (100) as claimed in claim 1, wherein the microcontroller (120) is a transistor-controlled ignition microcontroller.

11. A method for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition (102) is turned OFF, the method comprising:
activating a first relay (110) for a predetermined time when vehicle ignition (102) is turned OFF;
determining, based on input received from a first detection circuit (140), position of a headlamp switch (150);
activating a second relay (160), when the headlamp switch (150) is in ON position, thereby allowing the second relay (160) to provide DC power (A) to a beam control switch (170);
determining position of the beam control switch (170) based on input received from the second detection circuit (180); and
keeping the second relay (160) activated for the predetermined time if the beam control switch (170) is in a high beam position thereby illuminating the headlamp for the predetermined time after vehicle ignition (102) is turned OFF.
, Description:FIELD OF THE INVENTION
[001] The present invention generally relates to a delayed headlamp circuit for a vehicle, and more particularly to a circuit for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition is turned OFF.

BACKGROUND OF THE INVENTION
[002] In modern two-wheeled vehicles, delayed headlamp feature is generally incorporated as a safety feature. Delayed headlamp is in place to assist a rider whereby after parking the vehicle in night, the ambient lighting is very low, the headlamp remains ON for a predetermined time after an ignition key is switched OFF. While such feature is beneficial when ambient lighting is low, same is generally not required when surrounding is well lit in night. However, in conventional delayed headlamp systems, rider does not have option of disabling the feature of delayed headlamp for conditions when even in night time parking the ambient lighting is sufficient resulting in excess battery drain.
[003] Further, conventional delayed headlamp systems engage an additional control unit which adds complications in the vehicle circuitry and modifications in the existing vehicle design. Particularly for smaller vehicles like scooters and motorcycles where packaging space available is very limited, accommodation of additional components becomes a challenge.
[004] Furthermore, time delay in conventional systems is controlled by thermistors and relay combinations. As such, the time delay may not be accurate and consistent. Also, the sleep mode current used by conventional systems is high.
[005] Thus, there is a need in the art for a delayed headlamp circuit which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[006] In one aspect, the present invention is directed to a circuit for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition is turned OFF. In an embodiment of the invention, the predetermined time is 20 seconds. The circuit comprises of a microcontroller; a first relay configured to provide DC power from a battery to the microcontroller when the vehicle ignition is in OFF condition; a first detection circuit configured to detect ON position of a headlamp switch and to supply a signal to the microcontroller indicating the ON position of the headlamp switch; a second relay configured to provide DC power from the battery to a beam control switch, the beam control switch configured to connect a high beam light source or a low beam light source with the DC power; and a second detection circuit configured to detect a position of the beam control switch, and to supply a signal to the microcontroller indicating the position of the beam control switch. The microcontroller is configured to activate the second relay for the predetermined time if the beam control switch is detected to remain in a high beam position for illuminating the headlamp for the predetermined time after vehicle ignition is turned OFF.
[007] In an embodiment of the invention, the microprocessor is configured to: activate the first relay for a predetermined time when vehicle ignition is turned OFF; determine based on input received from the first detection circuit the position of the headlamp switch, activate the second relay when the headlamp switch is in ON position thereby allowing the second relay to provide DC power to the beam control switch; determine position of the beam control switch based on input received from the second detection circuit; and keep the second relay activated for the predetermined time if the beam control switch is in a high beam position thereby illuminating the headlamp for the predetermined time after vehicle ignition is turned OFF. In an embodiment, the microcontroller is a transistor-controlled ignition microcontroller.
[008] In an embodiment of the invention, the microcontroller is configured to monitor voltage of the battery and activate the first relay only when the battery voltage is above a threshold voltage.
[009] In another embodiment of the invention, the microcontroller is configured to activate the first relay only when the engine RPM crosses a first predetermined RPM between a last turning ON of the vehicle ignition and turning OFF of the vehicle ignition.
[010] In yet another embodiment of the invention, the microcontroller is configured to activate the first relay only when the engine RPM is below a second predetermined RPM after the vehicle ignition is turned OFF.
[011] In a further embodiment of the invention, the microcontroller is configured to receive a pulsating signal from the second detection circuit when the beam control switch is toggled between a high beam position and a low beam position within a predetermined duration and increase the predetermined time by a set increment. Herein, a cycle of toggling within the predetermined duration comprises of the beam control switch being positioned from a high beam position to a low beam position and back to a high beam position.
[012] In another embodiment of the invention, the circuit has an ambient light sensor for providing real time ambient lighting inputs to the microcontroller, the microcontroller activates the first relay only when real time ambient lighting inputs correspond to a night condition.
[013] In another aspect of the invention, the present invention is directed to a method for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition is turned OFF. The method comprises the steps of: activating a first relay for a predetermined time when vehicle ignition is turned OFF; determining based on input received from a first detection circuit position of a headlamp switch; activating a second relay when the headlamp switch is in ON position thereby allowing the second relay to provide DC power to a beam control switch; determining position of the beam control switch based on input received from the second detection circuit; and keeping the second relay activated for the predetermined time if the beam control switch is in a high beam position thereby illuminating the headlamp for the predetermined time after vehicle ignition is turned OFF.

BRIEF DESCRIPTION OF THE DRAWINGS
[014] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 shows a right-side view of an exemplary vehicle in accordance with an embodiment of the invention.
Figure 2 shows a circuit for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition is turned OFF in accordance with an embodiment of the invention.
Figure 3 shows a method for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition is turned in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[015] The present invention relates to a circuit for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition is turned OFF.
[016] Figure 1 illustrates a right-side view of an exemplary vehicle 10, in accordance with an embodiment of the present subject matter. The vehicle 10 comprises a frame assembly 12. The frame assembly 12 includes a head tube 12A, a main frame assembly 12B. One or more front suspensions 14 connect a front wheel 16 to a handlebar assembly 18, which forms a steering assembly of the vehicle 10. The steering assembly is rotatably disposed about the head tube 12A. The main frame assembly 12B extends rearwardly downward from the head tube 12A and includes a bent portion thereafter extending substantially in a longitudinal direction. Further, the frame assembly 12 includes one or more rear tubes 12C extending inclinedly rearward from a rear portion of the main frame assembly 12B towards a rear portion of the vehicle 10.
[017] The vehicle 10 includes a power unit comprising at least one of an internal combustion (IC) engine 22 and a traction motor 24. For example, the traction motor 24 may include a brush less direct current (BLDC) motor. The power unit is coupled to the rear wheel 26. In one embodiment, the IC engine 22 is swingably connected to the frame assembly 12. In one embodiment, the IC engine 22 is mounted to swing arm and the swing arm is swingably connected to the frame assembly 12. The traction motor 24, in one embodiment, is disposed adjacent to the IC engine 22. In one embodiment, the traction motor 24 is hub mounted to the rear wheel 26. Further, the vehicle 10 includes a transmission means coupling the rear wheel 26 to the power unit. The transmission means includes a continuously variable transmission, an automatic transmission, or a fixed ratio transmission. A seat assembly 28 is disposed above the power unit and is supported by the rear tubes 12C of the frame assembly 12. The seat assembly 28 is hingedly openable. The frame assembly 12 defines a step-through portion ST ahead of the seat assembly 28. A bottom structure 30 in the form of a floorboard is disposed at the step-through portion ST, wherein a rider can operate the vehicle 10 in a seated position by resting feet on the floorboard 30. Further, the floorboard 30 is capable of carrying loads.
[018] Further, the frame assembly 12 is covered by plurality of body panels including a front panel 32A, a leg shield 32B, an under-seat cover 32C, a left and a right-side panel 32D, and a rear panel 32E mounted on the frame assembly 12 and covering the frame assembly 12 and parts mounted thereof.
[019] In addition, a front fender 34 is covering at least a portion of the front wheel 16. A utility box is disposed below the seat assembly 28 and is supported by the frame assembly 12. A rear fender 36 is covering at least a portion of the rear wheel 26 and is positioned upwardly of the rear wheel 26. One or more suspension(s) are provided in the rear portion of the vehicle 10 for connecting the swing arm and the rear wheel 26 to the frame assembly 12 for damping the forces from the wheel 26 and the power unit from reaching the frame assembly 12.
[020] Furthermore, the vehicle 10 comprises of plurality of electrical and electronic components including a headlight 40, a taillight 42, a transistor-controlled ignition (TCI) unit (not shown), a battery, a magneto (not shown), and a starter motor (not shown).
[021] Figure 2 illustrates a circuit 100 for illuminating a headlamp of a vehicle for a predetermined time after the vehicle ignition 102 is turned OFF. As shown in Figure 2, the circuit 100 has a microcontroller 120. In an embodiment, the microcontroller 120 is a Transistor Controlled Ignition (TCI) microcontroller. Accordingly, when vehicle ignition 102 is turned ON, the microcontroller 120 receives DC power from a battery 130 through diode circuitry 114 and a voltage regulator 112 thereby controlling ignition operation of the vehicle.
[022] As shown in Figure 2, the circuit 100 has a first relay 110 configured to provide DC power (A) from the battery 130 to the microcontroller 120 when the vehicle ignition 102 is in OFF state. In this regard, one end of a coil 110a and one end of a normally open contact 110b of the first relay 110 are electrically connected to the battery 130. Another end of the coil 110a is connected to the microcontroller 120. Accordingly, when the microcontroller 120 provides a ground signal to the first relay 110, the coil 110a gets energized and thus the contact 110b gets closed. As shown in Figure 2, the contact 110b is connected to the microcontroller and therefore when the contact 110b moves to a closed position, the first relay 110 provides a DC power to the microcontroller 120 through the diode circuitry 114 and the voltage regulator 112. The routing of the DC power (A) supply to the microcontroller 120 through the first relay 110 ensures that the sleep mode current is less than the required value, wherein the sleep mode current is defined by the total current consumed by the vehicle when it is OFF condition. Since the moment the ignition 102 is turned OFF, the power from the battery 130 is no longer supplied to microcontroller 120, no sleep mode current is consumed.
[023] As shown in Figure 2, a first detection circuit 140 is connected to a headlamp switch 150. The headlamp switch 150 is connected to a regulator 104 which is further connected to a magneto 106. When the headlamp switch 150 is turned ON and the vehicle is in motion, the headlamp switch 150 provides power supply to a light source 172, 172’ through a second relay 160 and a beam control switch 170 from the regulator 104. The first detection circuit 140 is electrically connected to the headlamp switch 150 and the microcontroller 120. Further, the first detection circuit 140 is configured to detect ON position of the headlamp switch 150, and to supply a signal to the microcontroller 120 indicating the ON position of the headlamp switch 150. In an embodiment of the invention, the first detection circuit 140 converts AC voltage received when headlamp switch 150 is ON into levels suitable for processing by the microcontroller 120. The microcontroller is thus further configured to determine position of the headlamp switch 150 based on input received from the first detection circuit 140.
[024] The second relay 160 is configured to provide DC power (A) from the battery 130 to the beam control switch 170. In this regard, in an embodiment of the present invention and as shown in Figure 2, the second relay 160 is electrically connected to the headlamp switch 150 at a Normally Closed contact 160c of the second relay 160. The second relay is further connected to the beam control switch 170 at a common contact of the second relay 160. Accordingly, when the headlamp switch 150 is in ON condition, power from the magneto 106 is supplied to the light sources 172, 172’ through the beam control switch 170. One end of a coil 160a and a Normally Open contact 160b of the second relay 160 are electrically connected to the battery 130. Another end of the coil 160a is connected to the microcontroller 120. Accordingly, when the vehicle ignition 102 in OFF state, the microcontroller 120 provides a ground signal to the second relay 160 thereby energizing the coil 160a and closing the contact 160b. As a result, the battery 130 gets connected with the beam control switch 170. The beam control switch 170 is configured to connect a high beam light source 172 or a low beam light source 172’ with the DC power (A).
[025] As shown in Figure 2, a second detection circuit 180 is connected with the microcontroller 120 and receives a voltage input from a circuit connecting the light sources 172, 172’ with the beam control switch 170. Basis the voltage received by the second detection circuit 180, it supplies a signal to the microcontroller 120 indicating the position of the beam control switch 170.
[026] According to the present invention, the microcontroller 120 is configured to provide the ground signal to the first relay 110 for a predetermined time when the vehicle ignition 102 is switched OFF. In operation, when vehicle ignition 102 is switched OFF, the microcontroller provides a ground signal to the first relay 110 for a predetermined time thereby activating the first relay 110 and the DC power (A) is thus connected to the microcontroller 120 via diode circuitry 114 and the voltage regulator 112.
[027] As described hereinbefore, the microcontroller 120 is also configured to determine position of the headlamp switch 150 based on input received from the first detection circuit 140. If the headlamp switch 150 is ON, indicating that the vehicle is running in night condition, the microcontroller 120 is provides a ground signal to the second relay 160. If the headlamp switch 150 is OFF, indicating that the vehicle is not running in a night condition, the microcontroller 120 stops providing ground signal to the first relay 110.
[028] As described hereinbefore, in normal vehicle running condition, at night time, when headlamp switch 150 is ON, the beam control switch 170 will get power from a regulator 104 and magneto 106 via the Normally Closed contact of the second relay 160 and the headlamp be illuminated. When the vehicle ceases to be in the running condition meaning the ignition 102 is OFF and the headlamp switch 150 is ON, the microcontroller 120 provides ground signal to the second relay 160 thereby activating the second relay 160. When the second relay 160 is activated, the Normally Open contact 160b of the second relay 160 gets connected to the DC power (A) supply and resultantly, the beam control switch 170 will receive the DC power (A) through the Normally Open contact of the second relay 160.
[029] As described hereinbefore, the microcontroller 120 determines position of the beam control switch 170 based on input received from the second detection circuit 180. Herein, when the beam control switch 170 is in a high beam position, the same is detected by the second detection circuit 180 and communicated to the microcontroller 120. In this regard, the microcontroller 120 is configured to keep the second relay 160 activated for the predetermined time if the beam control switch 170 is in a high beam position which illuminates the headlamp 172 for the predetermined time through the beam control switch 170. In an embodiment of the present invention, the predetermined time is 20 seconds. If the beam control switch 170 is in a low beam position, the microcontroller 120 stops providing ground signal to the second relay 160, thereby deactivating the second relay 160 and turning the headlamp OFF. This allows the rider to keep the beam control switch 170 in the high beam position for when they desire for the headlamp to be illuminated for a predetermined time after the vehicle ignition 102 is turned OFF, and alternatively, keep the beam control switch 170 in the low beam position for when they do not desire for the headlamp to be illuminated after the vehicle ignition 102 is turned OFF.
[030] In an embodiment of the invention, the microcontroller 120 is configured to delay stopping of providing the ground signal to the second relay 160 by a set time period if the beam control switch 170 is in the low beam mode when the ignition 102 is turned OFF. If the beam control switch 170 is switched from the low beam position to the high beam position in the set time period, the microcontroller 120 is configured to continue the ground signal to the second relay 160, thereby illuminating the headlamp for the predetermined time. This allows for a situation when the rider desires for the headlamp to be illuminated for a predetermined time after the ignition 102 is turned OFF but has turned OFF the ignition 102 when the beam control switch 170 is in low beam position. The rider can thus switch the beam control switch 170 to high beam position within the set time period and resultantly, the headlamp shall be illuminated for the predetermined time. In an embodiment of the invention, the set time period is 20 seconds.
[031] In an embodiment of the present invention, the microcontroller 120 is further configured to monitor voltage of the battery 130 and activate the first relay 110 after the ignition 102 is switched OFF only when the battery 130 voltage is above a threshold voltage. This ensures that when the State of Charge of the battery 130 is low, the headlamp is not illuminated after the ignition 102 is turned OFF, preventing the battery 130 from deep discharge. In an embodiment of the present invention, the threshold voltage is 10.5V.
[032] In an alternate embodiment of the present invention, the microcontroller 120 is further configured to activate the first relay 110 after the ignition 102 is turned OFF only when the engine RPM crosses a first predetermined RPM between a last turning ON of the vehicle ignition 102 and turning OFF of the vehicle ignition 102. This ensures that the battery 130 remains sufficiently charged, preventing the battery 130 from deep discharge. In an embodiment of the present invention, the first predetermined RPM is 2000 RPM.
[033] In an embodiment of the present invention, the microcontroller 120 is further configured to activate the first relay 110 after the ignition is turned OFF only when the engine RPM is below a second predetermined RPM after the vehicle ignition 102 is turned OFF. This ensures that in a situation where the user has turned the ignition 102 OFF, but the vehicle has not completely stopped, if the rider desires for the headlamp to be illuminated after the vehicle ignition 102 is turned OFF, the headlamp is illuminated even if the vehicle has not come to a complete stop. In an embodiment of the present invention, the second predetermined RPM is 2000 RPM.
[034] In an embodiment of the present invention, the microcontroller 120 is configured to receive a pulsating signal from the second detection circuit 180 when the beam control switch 170 is toggled between a high beam position and a low beam position within a predetermined duration; and increase the predetermined time by a set increment. In that, a cycle of toggling within the predetermined duration comprises of the beam control switch 170 being positioned from a high beam position to a low beam position and back to a high beam position. This results in the rider having the option of illuminating the headlamp after the ignition 102 is turned OFF for a period greater than the predetermined time. In an embodiment of the present invention, the predetermined duration is 1 second. In an embodiment of the present invention, the set increment can be 10 seconds or 20 seconds.
[035] As shown in Figure 2, an ambient light sensor 190 is connected to the microcontroller 120 which provides real time ambient lighting inputs to the microcontroller 120. Herein, the microcontroller 120 is configured to activate the first relay 110 only when real time ambient lighting inputs corresponds to a night condition.
[036] Figure 3 illustrates a method 200 for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition 102 is turned OFF. The method is performed on the circuit 100 discussed hereinbefore. The method begins at step 210 where the first relay 110 is activated for a predetermined time when vehicle ignition 102 is turned OFF, thereby allowing the microcontroller 120 to receive DC power (A) through the first relay 110. In an embodiment of the present invention, the predetermined time is 20 seconds. Thereafter, at step 220, the position of the headlamp switch 150 is determined based on the input received from the first detection circuit 140. If the headlamp switch 150 is in OFF position, the first relay 110 is deactivated. If the headlamp switch 150 is ON, the method moves to step 230. At step 230, a second relay 160 is activated when the headlamp switch 150 is in ON position, thereby allowing the second relay 160 to provide DC power (A) to a beam control switch 170. Further at step 240, the position of the beam control switch 170 is determined based on input received from the second detection circuit 180. If the beam control switch 170 is in the low beam position, the second relay 160 is deactivated. If the beam control switch 170 is in the high beam position, the method moves forward to step 250. At step 250, the second relay 160 is kept activated for the predetermined time if the beam control switch 170 is in a high beam position thereby illuminating the headlamp for the predetermined time after vehicle ignition 102 is turned OFF.
[037] Advantageously, the present invention provides a circuit for illuminating a headlamp of a vehicle for a predetermined time after vehicle ignition is turned OFF wherein the rider has an option to disable this feature when they desire, especially for conditions when ambient lighting is sufficient in night time. Further, the present invention also prevents the use of an additional component such as a body control unit, resulting in better packaging space which is especially important for two-wheeled vehicle such as scooters or motorcycles. Furthermore, in the present invention the time delays are reliable and accurate as the present invention involves a microcontroller and the sleep mode current is zero.
[038] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.