DESC:Technical Field
[0001] The present subject matter described herein generally relates to a control system and particularly relates to an electronic control system for a lighting assembly of a vehicle, and to a control method thereof.
Background
[0002] It is well known that vehicles are increasingly being provided with internal combustion engines operatively linked to a start stop system as one of the means for reducing emissions. Said start stop system operates in a manner so as to ensure that the engine is automatically turned off when the vehicle is stopped, and when a throttle is operated to move the vehicle, the engine is automatically turned on to restart the vehicle. Particularly, the engine is restarted by a starter device which draws energy from an electrical energy source such as a battery.
[0003] Besides powering the starter device, said electrical energy source also powers a front lighting assembly including a headlamp device. Typically, the energy required to power said headlamp device is drawn either from the electrical energy source such as a battery or an alternating current (AC) generator (also called a magneto) connected with the engine. The battery is particularly charged through a regulator-rectifier unit which converts the alternating current generated by said magneto into regulated direct current. However, at low engine speeds, voltage generated by said magneto is low and the battery may not be sufficiently charged during such conditions. Therefore, in such conditions when the battery is not sufficiently charged, having the headlamp device turned on continuously, especially in engine idling conditions, may result in draining of the battery.
[0004] Problems relating to draining of battery due to continuous operation of the headlamp device proves to be particularly detrimental in vehicles powered by a full DC based charging system and including an engine start/stop control unit, because the headlamp device continues to glow even when the engine is turned off by the start stop system, and particularly because non starting of the vehicle due to low battery defeats the whole purpose of easy start stop logic for the customer.
[0005] It is therefore desirable to optimise functioning of said headlamp device for continuous working while ensuring good state of charge of battery for a vehicle.
Summary of the Invention
[0006] The present invention has been made in view of the above circumstances.
[0007] It is an object of the present invention to provide a vehicle with an electronic control system which is adapted to control operation of a front lighting assembly including a headlamp device besides exercising engine start stop control.
[0008] It is another object of the present invention to provide a vehicle with an electronic control system which is adapted to control operation of said headlamp device based on state of charge of an electrical energy source during an engine OFF condition.
[0009] It is yet another object of the present invention to provide a vehicle with an electronic control system which is adapted to control operation of said headlamp device during an engine ON condition including engine idling condition.
[0010] It is still another object of the present invention to provide a vehicle with an electronic control system which is adapted to control operation of the headlamp device based on inputs received from a pulser coil, a headlamp switch, a headlamp beam control switch, a pass by switch, an engine start stop switch, an electrical energy source such as a battery, and a position sensor such as a throttle position sensor.
[0011] With the above and other objects in view, the present invention provides a vehicle with an electronic control system comprising an electronic control unit, hereinafter ‘controller’ for controlling operation of a lighting assembly including a headlamp device, said lighting assembly being powered by an electrical energy source. As per an embodiment of the present invention, in order to control the operation of the headlamp device under different vehicle operating conditions, the controller is adapted to be responsive to a position of the headlamp switch, the headlamp beam control switch, and the pass by switch of the lighting assembly, besides being responsive to inputs from a pulser coil operatively connected to an engine of the vehicle, and to a position of an engine start stop switch. Further, the controller is also adapted to receive inputs from the electrical energy source such as the battery.
[0012] The present invention describes a method of operation of the controller, including a method for controlling operation of said headlamp device in an engine ON condition, and an engine OFF condition.
[0013] In one embodiment, a method of operation of the controller for controlling operation of the headlamp device during engine ON/OFF conditions is described. The method includes detecting the position of the engine start stop switch, detecting state of charge of the electrical energy source; reducing operating voltage of the headlamp device by performing pulse width modulation (hereinafter ‘PWM’) for a first predetermined duration based on state of charge of the electrical energy source if the engine has stopped owing to selection of said start stop switch; and reducing operating voltage of the headlamp device by performing pulse width modulation (hereinafter ‘PWM’) for a second predetermined duration if the engine is idling for a predefined duration owing to non selection of the start stop switch. In other words, when the engine is switched OFF in a condition when start stop switch is ON, the headlamp device is operated with reduced operating voltage by performing PWM for the first predetermined duration after verification of a state of charge of the electrical energy source. However, when the engine idles for the predefined duration in a condition where the start stop switch is OFF, the headlamp device is operated with reduced operating voltage by performing PWM for the second predetermined duration. Thus, by reducing the operating voltage of the headlamp device after verification of the state of charge of the electrical energy source and when the vehicle is stopped owing to selection of said start stop switch, it is ensured that sufficient charge of the electrical energy source is conserved and made available at a time when the engine is about to restart. Thus, non starting of the engine in a vehicle employing an engine start stop system due to lack of sufficient charge in the electrical energy source, can be prevented. Moreover, since the headlamp device is adapted to be operated at reduced operating voltage when the start stop switch is unselected, conservation of charge is possible even when the start stop system is not operational. Thus, by reducing the effective voltage supplied to the headlamp device by performing PWM, the controller aids in reducing energy consumption from the electrical energy source.
[0014] Further, the present invention also describes a method of operation of the electronic control unit for controlling operation of the headlamp device when the pass by switch is selected in different riding conditions.
[0015] Summary provided above explains the basic features of the invention and does not limit the scope of the invention. The nature and further characteristic features of the present invention will be made clearer from the following descriptions made with reference to the accompanying drawings.

Brief Description of Drawings
[0016] The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description and accompanying drawings where:
[0017] FIG.1 is a schematic representation of a circuit of the electronic control system in accordance with an embodiment of the present invention.
[0018] FIG.2 illustrates a flow chart depicting steps of a method of operation of the electronic control system controlling operation of a lighting assembly in accordance with a first embodiment of the present invention.
[0019] FIG.3 illustrates a flow chart depicting steps of a method of operation of the electronic control system controlling operation of a lighting assembly in accordance with a second embodiment of the present invention.
Detailed Description of the Preferred Embodiments
[0020] The present subject matter described herein provides for an electronic control system for controlling operation of a front lighting assembly of a vehicle, said front lighting assembly including a headlamp device capable of illuminating a road in front of said vehicle. Particularly, the electronic control system includes an electronic control unit, hereinafter ‘controller’ for controlling operation of the headlamp device in different engine operating conditions including during engine idling conditions. More particularly, the controller is also adapted to determine engine operating conditions of an internal combustion engine, hereinafter ‘engine’, which is controlled by an engine start stop system, by being responsive to a manually operable engine start stop switch. Besides, according to an aspect of the invention, the controller also controls operation of the headlamp device in relation to different manually maintained positions of a headlamp switch, a headlamp beam control switch, and a pass by switch of said lighting assembly during engine ON or engine OFF conditions.
[0021] Exemplary embodiments detailing features of the electronic control system, in accordance with the present invention will be described hereunder. The embodiments described herein apply to a vehicle powered by the engine, said engine being controlled by the engine start stop system. However, the present invention is not restricted in its application and is also applicable to vehicles employing an engine start stop system and adapted to be powered selectively either by an engine or a traction motor or by both the engine and the traction motor. Further, the present invention is also applicable to vehicles employing an engine start stop system and adapted to be powered by an engine operatively connected to an integrated starter generator. Furthermore, the present invention is applicable to electric vehicles, said electric vehicles comprising a traction motor as a power unit.
[0022] The present embodiment of the invention applies to a vehicle powered by a power unit including said engine, said engine being operatively connected to a pulser coil and adapted to be controlled by said engine start stop system. The vehicle further comprises a front lighting assembly energized by an electrical energy source such as a battery; said lighting assembly including a headlamp device, a headlamp switch, a headlamp beam control switch and a pass by switch. The electronic control system includes the controller which is operatively connected to said lighting assembly, and communicatively connected to the pulser coil, said start stop switch and said electrical energy source. Further, the controller is also operatively connected to an ignition switch used for starting the vehicle.
[0023] Referring to FIG.1, a description is made of a schematic representation of the electronic control system A as per an embodiment of the present invention. As may be seen, the electronic control system A includes a magneto assembly 1 which generates an alternating current due to a rotating magnetic field. Alternating current from the magneto assembly 1 is rectified and regulated by a Regulator and Rectifier, hereinafter ‘RR unit’ 2 into direct current. The RR unit 2 maintains a direct current voltage within strict tolerances to ensure optimum charging of the electrical energy source 3 and satisfactory performance of all vehicle loads. A fuse 4 protects said electrical energy source 3 against short circuit conditions. When an ignition switch 11 in the vehicle is turned ON, the electrical energy source 3 supplies direct current to an electronic control unit, hereinafter ‘controller’ 6. The controller 6 is adapted to receive inputs from various manually operable switches of said lighting assembly including the headlamp switch 7, the headlamp beam control switch 8, and the pass by switch 9. Particularly, the controller 6 drives a headlamp low beam mode, a headlamp high beam mode, and a toggle mode in which the headlamp device (not shown) toggles between the high beam mode and the low beam mode or vice versa based on position of the headlamp beam control switch 8 and a corresponding position of the pass by switch 9. Further, the controller 6 also takes input from other manually operable switches such as an engine start stop switch 10 and the ignition switch 11. In one embodiment of the present invention, the controller 6 may also be responsive to a throttle position sensor. Besides the above mentioned manually operable switches, the controller 6 also receives inputs from a pulser coil 12, for calculating engine speed from a pulser coil signal generated by said pulser coil 12. Particularly, the controller 6 includes a microcomputer which calculates engine speed from an input given in the form of pulser coil signal and processes the same based on predetermined engine speed values stored therein. Information processed by the microcomputer is sent as an input signal to a headlight driver encompassed in the controller 6. In the present embodiment, the controller 6 also controls spark ignition by driving an ignition coil. Further, the controller 6 is also adapted to receive and process inputs from said electrical energy source 3 regarding state of charge of said energy source.
[0024] FIG.2 represents a flow chart which represents the steps of operation of the controller 6 for operating a headlamp device under different conditions. In a first step of its operation and as per a first embodiment of the present invention, the controller 6 determines operation of the headlamp device based on the position of the ignition switch 11 and based on inputs from the pulser coil 12. Further, in the first step of operation, the electronic control unit 6 also takes input from the headlamp switch 7. Based on the inputs of the pulser coil 12 regarding engine speed, the headlamp device is allowed to operate when the engine speed is above a particular predetermined value and if the headlamp switch 7 is ON. For example, if the ignition switch 11 is ON and the engine speed is greater than 1100rpm for 2s, with the headlamp switch 7 being ON, the headlamp device is switched ON. However, if the engine speed is less than 1100rpm for 2s, the headlamp device is not allowed to be switched ON even if the headlamp switch 7 is ON.
[0025] Further, in a condition when the headlamp device is switched ON for operation, the controller 6 checks for position of said start stop switch 10, whether the same is switched ON or switched OFF. In a condition when the start stop switch is ON, and when the controller 6 detects that the engine is switched OFF resulting in stoppage of said vehicle, it further checks for state of charge of the electrical energy source 3, and based on a predetermined state of charge of the electrical energy source 3 stored in controller memory, say for example in table A; the controller 6 determines whether the headlamp device should be operated at a reduced operating voltage by performing pulse width modulation, hereinafter ‘PWM’ or whether the headlamp device should be switched OFF. For example, when the state of charge of the electrical energy source 3 is less than 50% of the predetermined state of charge stored in controller memory, the headlamp device is made to function with headlight output duty cycle at 50% by performing PWM for a first predetermined duration, say for example 5 minutes. Further, in a condition when the state of charge of the electrical energy source 3 is less than 40% of the predetermined state of charge stored in the controller, the headlamp device is made to function with headlight output duty cycle at 40% by performing PWM for 5 minutes. Furthermore, in a condition when the state of charge of the electrical energy source 3 is less than 30% of the predetermined state of charge stored in the controller, the headlamp device is switched OFF. Thereby, it is ensured that when the state of charge of the electrical energy source 3 is less than the predetermined state of charge stored in controller memory, intensity of the headlamp device is reduced either by 50% or 40% or the headlamp device is made to switch OFF completely so that enough charge is conserved for the restarting of the engine when an input for the same is received by the controller 6 from the engine start stop system. Further, as per an aspect of the present invention, the controller is also adapted to transmit to an instrument cluster, information relating to state of charge of the electrical energy source. For example, a low battery indication will be displayed on a display panel of the instrument cluster when the controller 6 voluntarily switches off the headlamp device.
[0026] However, in a condition when the controller 6 detects that a rider has failed to switch on said start stop switch 10, and the engine is at idling condition for a time more than a predefined time duration, say for example for more than 10s, then the headlamp device is made to function with headlight output duty cycle at 50% by performing PWM for a second predetermined duration, say for example 10 minutes. Thus, the headlamp device is made to glow with reduced intensity at engine idling conditions so that charge of the electrical energy source 3 is not drained out. Further, besides controlling the operation of the headlamp device based on state of charge of the electrical energy source, the controller 6 also sends out an indication of the state of charge of the electrical energy source to the display panel, thus intimating a rider of the state of charge of the electrical energy source 3.
[0027] Besides controlling operation of the headlamp device during different engine operating conditions, the controller 6 also controls functioning of the headlamp device based on inputs received from the headlamp switch, the headlamp beam control switch and the pass by switch. For example, when the pass by switch 9 is activated when the headlamp switch 7 is ON and the headlamp beam control switch 8 is positioned to function in the low beam mode, then the controller 6 causes the headlamp device to function in a toggle mode, wherein the headlight device toggles from the low beam mode to the high beam mode and back to the low beam mode when the pass by switch 9 is deactivated. Similarly, if the pass by switch 9 is activated when the headlamp switch 7 is ON and the headlamp beam control switch 8 is positioned to function in the high beam mode, then the electronic control unit 6 causes the headlamp device to function in the toggle mode, wherein the headlamp device toggles from the high beam mode to the low beam mode and back to the high beam mode when the pass by switch 9 is deactivated. Thus, the controller 6 aids in generating a discernible change in the headlamp lighting, due to which passing intention can be clearly communicated to an oncoming rider. Thus, the automatic toggling of the headlamp device when the pass by switch 9 is activated does away with the need of performing a highly repetitive action of manually switching between the high beam mode and the low beam mode, thus facilitating driver convenience.
[0028] Further, the controller 6 also enables the driver to communicate the pass signal effectively even during daylight conditions. For example, during daylight conditions when the headlamp switch 7 is OFF, and the pass by switch 9 is activated to signal crossing/over taking, the controller 6 causes the headlamp device to glow with full brightness in the high beam mode. Moreover, in an engine non-operating condition but where the ignition switch 11 is ON, a condition which is commonly observed when the vehicle is standing at a traffic signal; the driver may switch on the pass by switch 9 to indicate that he/she is about to pass or over-take a vehicle waiting ahead. In such a situation, when the pass by switch is switched on, the electronic control unit 6 causes the headlamp device glow in high beam mode. Thus, safety feature of the vehicle is ensured completely while ensuring that electrical energy source is not unnecessarily discharged.
[0029] The present invention when applied to an electric vehicle follows the same method of operation as described above except that instead of engine rpm, the controller will control headlamp operation based on inputs related to vehicle rpm as determined by the throttle position sensor. Therefore, the controller is communicatively connected to said throttle position sensor for receiving inputs regarding vehicle rpm/vehicle speed.
[0030] FIG.3 denotes a flow chart depicting steps of a method of operation of the electronic control system controlling operation of a lighting assembly in accordance with a second embodiment of the present invention. The second embodiment of the present invention deals with a headlamp device to be operated in Automatic Headlamp ON condition. As may be seen in FIG.3, in a condition when the engine rpm exceeds a predetermined engine rpm for a predetermined duration, say for example when the engine rpm is greater than 1100 for 2s and when the headlamp switch is OFF, the controller 6 causes the headlamp device to operate at a reduced operating voltage of 50% by performing PWM switching. Thus, the headlamp device is made to operate during day and night conditions even when the headlamp switch is OFF. Since the headlamp device is made to operate at an operating voltage of 50%, charge from said electrical energy source 3 is not drained easily. Functioning of the controller 6 for performing other headlamp device related control operations remains the same as explained for the first embodiment.
[0031] These and other modifications are possible without departing from the spirit and scope of the invention.
[0032] While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
The following reference numerals have been used in the drawings:
A: Electronic control system
1: Magneto assembly
2: Regulator and Rectifier Unit (RR unit)
3: Electrical energy source
4: Fuse
6: Electronic control unit (controller)
7: Headlamp switch
8: Headlamp beam control switch
9: Pass by switch
10: Engine Start stop switch
11: Ignition switch
12: Pulser coil
,CLAIMS:I/We Claim:
1. An electronic control system (A) for a vehicle, said vehicle comprising:
an engine to power said vehicle upon switching ON of an ignition switch (11);
a pulser coil (12) operatively connected to the engine and configured to determine engine speed;
an engine start stop switch (10) for controlling engine operation;
a front lighting assembly including a headlamp device, a headlamp switch (7) to operate said headlamp device; and,
an electrical energy source (3) operatively connected to the front lighting assembly including said headlamp device for powering said lighting assembly besides vehicle electrical loads;
wherein, the electronic control system (A) includes a controller (6) operatively connected to the ignition switch (11) and to the front lighting assembly, and communicatively connected to the pulser coil (12) for controlling operation of the headlamp device;
characterized in that, said controller (6) being communicatively connected to said start stop switch (10), and to the electrical energy source (3), is responsive to inputs received from the engine start stop switch (10) and the electrical energy source (3) in order to control operation of the headlamp device, wherein the headlamp device is made to operate at a reduced operating voltage selected from a range of operating voltages when the vehicle has stopped temporarily, and when a state of charge of the electrical energy source (3) is less than a predetermined state of charge stored in controller memory.
2. The electronic control system (A) as claimed in claim 1, wherein the headlamp device is made to operate at a reduced operating voltage by performing pulse width modulation for a first predetermined duration when the vehicle has stopped temporarily owing to selection of said start stop switch (10).
3. The electronic control system (A) as claimed in claim 1, wherein the headlamp device is made to operate with headlight duty cycle at 50% when the vehicle has stopped temporarily with the engine in idling condition for a time more than 10s by performing pulse width modulation for a second predetermined duration
4. The electronic control system (A) as claimed in claim 1 or claim 2, wherein the headlamp device is made to operate with a headlight output duty cycle at 50% when the vehicle has stopped temporarily owing to selection of said start stop switch (10) and when state of charge of the electrical energy source (3) is less than 50% of the predetermined state of charge stored in controller memory.
5. The electronic control system (A) as claimed in claim 1 or claim 2, wherein the headlamp device is made to operate with a headlight output duty cycle at 40% when the vehicle has stopped temporarily owing to selection of said start stop switch (10) and when state of charge of the electrical energy source (3) is less than 40% of the predetermined state of charge stored in controller memory.
6. The electronic control system (A) as claimed in claim 1 or claim 2, wherein the headlamp device is switched OFF when the vehicle has stopped temporarily owing to selection of said start stop switch (10) and when state of charge of the electrical energy (3) source is less than 30% of the predetermined state of charge stored in the controller memory.
7. An electronic control system (A) for a vehicle, said vehicle comprising:
an engine to power said vehicle upon switching ON of an ignition switch (11);
a pulser coil (12) operatively connected to the engine and configured to determine engine speed;
a front lighting assembly including a headlamp device, a headlamp switch (7) to operate said headlamp device; and,
an electrical energy source (3) operatively connected to the front lighting assembly including said headlamp device;
wherein the electronic control system (A) includes a controller (6) communicatively connected to the pulser coil (12), and operatively connected to the front lighting assembly, for controlling operation of the headlamp device;
characterized in that, said controller (6) being responsive to a pulser coil signal for engine rpm generated by said pulser coil (12) and to a position of the headlamp switch (7) including a headlamp switch ON position and a headlamp switch OFF position, causes the headlamp device to operate at a reduced operating voltage, when engine rpm detected by the controller (6) exceeds a predetermined engine rpm for a predetermined duration and the headlamp switch (7) is in said headlamp switch OFF position.
8. A control method for operation of an electronic control system (A) for a vehicle, said vehicle including:
an engine to power said vehicle upon switching ON of an ignition switch (11);
a pulser coil (12) operatively connected to the engine and configured to determine engine speed;
an engine start stop switch (10) for controlling engine operation;
a front lighting assembly including a headlamp device, a headlamp switch (7) to operate said headlamp device; and,
an electrical energy source (3) operatively connected to the front lighting assembly including said headlamp device;
wherein, said electronic control system (A) includes a controller (6) communicatively connected to said pulser coil (12), and operatively connected to said front lighting assembly and said ignition switch (11);
characterized in that, said controller (6) is communicatively connected to said engine start stop switch (10), and wherein said control method comprises the steps of:
detecting engine rpm based on pulser coil signal for engine rpm;
detecting a position of said headlamp switch (7), including a headlamp switch ON position, and a headlamp switch OFF position;
enable the headlamp device to operate when engine rpm detected exceeds a predetermined engine rpm for a predetermined duration;
detecting engine operating condition based on input signal received from said start stop switch (10);
checking state of charge of the electrical energy source (3) when the vehicle has stopped owing to selection of said start stop switch (10) and as communicated by input signal received from said start stop switch (10);
reducing an operating voltage of the headlamp device correspondingly by performing PWM by comparing with a predetermined state of charge value stored in controller memory, when said vehicle has stopped temporarily owing to selection of said start stop switch (10);
reducing the operating voltage of the headlamp device to 50% by performing PWM switching, when the engine is idling for a time more than a predefined time duration with said start stop switch (10) being unselected.
9. The control method for operation of said electronic control system (A) as claimed in claim 8, wherein said controller (6) enables the headlamp device to operate when engine rpm detected exceeds engine rpm of 1100rpm for 2s, when said ignition switch (11) is ON and said headlamp switch (7) is in one of said headlamp switch ON position or said headlamp switch OFF position.
10. An electronic control system (A) for a vehicle, said vehicle comprising:
a power unit to drive said vehicle upon switching ON of an ignition switch (11); and
a front lighting assembly including a headlamp device for illuminating a road in front of said vehicle; and
an electrical energy source (3) for supplying power to vehicle electrical loads, besides said electronic control system (A);
wherein, the electronic control system (A) includes a controller (6) receiving power from said electrical energy source (3) and operatively connected to the ignition switch (11), and the front lighting assembly, for controlling operation of the headlamp device;
characterized in that, the controller (6) being communicatively connected to said electrical energy source (3), is responsive to inputs received from the electrical energy source (3) in order to control operation of the headlamp device, wherein the headlamp device is made to operate at a reduced operating voltage selected from a range of operating voltages when the vehicle has stopped temporarily, and when a state of charge of the electrical energy source (3) is less than a predetermined state of charge stored in controller memory.