Hazard Warning System

Field of the Invention:

This invention relates to a hazard warning system in a two-wheeled vehicle and more particularly for visually indicating a potential hazard to other riders during low visibility conditions.

Background of the Invention:

Two-wheelers are increasingly being used for personal transportation over distances long and short and in both day and night conditions. While being used on different roads and in different weather conditions, the vehicles might fail to operate suddenly. The user gets stranded on the road and he/she might have to troubleshoot the failure and get the vehicle back to running condition. Common tools required for dismantling the vehicle like spanners and screw drivers are provided in the tool kit for such emergency procedures. If the vehicle fails to operate during low visibility conditions like night condition and/or during thick fog, there is a potential hazard that on coming vehicles might collide with the stranded vehicle that is being diagnosed on the road. Obviously the two-wheeler can be moved to a vacant side of the road, preferably on the left side of the road (in India) while viewing in the driving direction. But there are narrow roads which create hazardous conditions wherein the stranded vehicle cannot be moved outside a possible path of an oncoming vehicle. During such conditions, it is desirable to provide a visual indication to the oncoming riders about the potential hazard and warn about a stationary vehicle on the road.

US Patent US3784975 titled "Alternately Flashing Warning System" discloses a circuit for flashing high beam filaments of vehicle headlamps in order to provide a warning signal. When a warning switch is turned ON, a flasher unit connects a vehicle battery to headlamp high beam filaments and thereby causes the headlamp high beam filaments to blink at a predetermined flashing rate.

Japanese Patent JP1996239072 titled "Dimming Controller for Head-Lamp of Motorcycle" discloses a circuit for enabling blinking of all four turn signal lamps of a motorcycle when a hazard switch is turned ON. When a turn signal switch for either left turn or right turn is switched ON, a flasher unit connects a vehicle battery to the corresponding turn signal lamps at a predetermined rate and the turn signal lamps blink to indicate the turn. When a hazard warning switch is turned ON, a relay connects all four turn signal lamps to the flasher unit such that the lamps blink simultaneously.

The hazard warning systems mentioned above do not consider the possibility of battery draining due to continuous operation of the hazard warning system. As the engine or motor in the vehicle might have failed and the vehicle is stationary, the hazard warning system has to be powered by on-vehicle battery. If the operation of the hazard warning system continues for a long time due to prolonged vehicle diagnostics, the battery state of charge decreases and it will be difficult to thereafter start the vehicle by electric start or use other high current loads. The hazard warning systems mentioned above also have a limited operating duration as the simultaneous blinking of four turn signal lamps will discharge the battery at a fast rate. Batteries with higher capacity might have to be used to supply energy to the turn signal lamps for sufficient duration. This increases the cost and size of the system.

Therefore, a hazard warning system that can control the energy supplied by vehicle battery without compromising on providing hazard indication during emergency conditions is desirable.

Summary of the Invention:

An Electronic Control Unit (ECU) receives a hazard switch input signal and controls the power supplied to the turn signal lamps based on the battery voltage sensed. In a first embodiment, the duty cycle of the voltage supplied to the turn signal lamps is varied by the ECU in order to limit battery discharge. As the battery voltage decreases during operation of the hazard warning system, the duty cycle of voltage supplied also decreases. In a second embodiment, the ECU controls the number of turn signal lamps blinking simultaneously based on the battery voltage sensed. With battery voltage beyond a predetermined value, all the four turn signal lamps are connected to a flasher unit in order to blink simultaneously. As the battery voltage decreases, the number of turn signal lamps connected to the flasher unit is reduced in steps.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief Description of the Drawings:

Figure 1 is a pictorial front view of a two wheeler with the hazard warning system.

Figure 2 is a pictorial view of the switch controls and display unit from the operator position.

Figure 3 is a block diagram representation of a preferred embodiment of the hazard warning system

Figure 4 is a block diagram representation of a second embodiment of the hazard warning system

Detailed Description of the Drawings:

Referring to Fig 1, two-wheeler 10 has a frame 20 forming the structure to which all the parts are connected. An engine 30 is mounted on the frame 20 for converting the chemical energy available in fuel into mechanical energy required for driving the two-wheeler 10. The front side of the frame 20 has a headlamp assembly 40 connected for illuminating the road in low visibility conditions. A handle bar assembly 50 is connected with a front wheel assembly (not shown in figure) through a front fork assembly 60 for steering the two-wheeler 10. The two-wheeler 10 has a front left-turn signal lamp 70 and front right-turn signal lamp 80 connected with the headlamp assembly 20 for indicating oncoming vehicles about an intended turn. On the rear side of the frame 20, rear left-turn signal lamp 90 and rear right-turn signal lamp 100 are connected to indicate an intended turn to the vehicles running behind.

Referring to Fig 2, the handlebar assembly 50 has a switch assembly LH 110 and switch assembly RH 120 fitted on the left and right side of the handlebar assembly 40 respectively when viewed from the rider end. The switch assembly LH 110 has a horn switch 130, a TSL (Turn Signal Lamp) switch assembly 140 for controlling the turn signal lamps 70, 80, 90 and 100 and beam selection switch 150. The switch assembly RH 120 has an Electric Start (ES) switch 160 for cranking the engine 30 by electric start, a headlamp switch assembly 170 for controlling the headlamp and a hazard warning switch 180 for activating hazard warning indication.

During the riding condition of the two-wheeler 10, the operator switches a TSL (Turn Signal Lamp) switch assembly 140 to either left-turn or right-turn based on the intended turning direction. The TSL switch assembly 140 is a three way switch with one position each for left-turn indication, right-turn indication and cancellation. Either left-turn signal lamps 70 and 90 or right turn signal lamps 80 and 100 blink at a predetermined rate based on the TSL switch assembly 140 position. After completing the turn, the operator switches the TSL switch assembly 140 to cancelling position in order to stop the turn signal lamps blinking. The TSL switch assembly 140 position is indicated in speedometer assembly display 190 for the benefit of the rider.

Referring to Fig 3, a flasher 200 produces a pulsed voltage at a predetermined frequency required for flashing lamps. The TSL switch assembly 140 has internally a left TSL switch 142 and right TSL switch 144. When the operator is intending to make a left turn, the TSL switch assembly 140 knob is moved by operator so that left TSL switch 142 is closed. This will connect the flasher 200 output to left turn signal lamps 70 and 90. If the operator is intending to make a right turn, the TSL switch assembly 140 knob is moved by operator so that right TSL switch 144 is closed. This will connect the flasher 200 output to right turn-signal-lamps 80 and 100. The corresponding turn signal lamps flash to indicate the intended turn. After making the turn, the operator moves the TSL switch assembly 140 knob to stop the bulbs flashing during which both TSL switches 142 and 144 remain open. The flasher 200 receives battery voltage (+12V) supply 240
through a vehicle wiring harness.

In order to provide a hazard warning feature, it is required to flash all four turn signal lamps 70, 80, 90 and 100 simultaneously at a predetermined frequency. In order to achieve this feature, the hazard warning switch 180 provides a ground signal 230 to an Electronic Control Unit (ECU) 210. The ECU 210, in addition to other engine control and vehicle control functions, connects the flasher 200 output to turn signal lamps 70, 80, 90 and 100 when predetermined conditions are satisfied. Internally, the ECU has a microcontroller 212 for performing the necessary arithmetic and logic operations and for producing required driving signals. The ECU 210 also has electronic switches 214 and 216 for connecting flasher 200 output to lamps based on microcontroller 212 driving signals. The ECU 210 determines the state of charge of battery from battery voltage input 220.

If the state of charge of battery is above a predetermined threshold, the microcontroller 212 turns ON the electronic switches 214 and 216 with 100% duty cycle so that the flasher 200 output is directly connected to turn signal lamps 70, 80, 90 and 100. If the state of charge of battery is low, in order to reduce the battery discharge rate, the electronic switches 214 and 216 are switched at a high frequency with duty cycle less than 100%. This in turn reduces the average voltage applied to the turn signal lamps and thereby reduces energy consumption. The duty cycle of switching of the electronic switches 214 and 216 is varied based on the battery input voltage 220 so that the energy consumed will decrease as the battery state of charge decreases. The electronic switches 214 and 216 allow one way transmission of current and therefore prevent all the turn signal lamps from flashing simultaneously if hazard switch 180 is open. When the battery voltage reaches a predetermined minimum limit, the duty cycle is reduced to 0% such that there is no further battery discharge. This can ensure good startability and allow electric start functionality. As the energy consumed by the turn signal is decreased proportional to the decrease in battery voltage, the battery service time is extended.

In another embodiment of the hazard warning system as shown in Fig 4, the ECU 210 comprises of additional electronic switches 213, 215, 217 and 219 which connect the flasher 200 output to each turn signal lamp 70, 90, 80 and 100 respectively based on microcontroller 212 driving signals. If the state of charge of battery assessed from battery voltage input 220 is high, then microcontroller 212 drives all four electronic switches 213, 215, 217 and 219 such that flasher 200 output is connected to all four turn signal lamps 70, 80, 90 and 100 simultaneously. If the battery state of charge is low, then the number of turn signal lamps flashing simultaneously is limited by selectively switching ON electronic switches 213, 215, 217 and 219. As the battery state of charge decreases, the number of electronic switches turned ON is also decreased in steps. When the battery voltage reaches a predetermined minimum limit, none of the turn signal lamps are switched ON to ensure good startability and electric start functionality. Thus battery life is prolonged without seriously impairing hazard warning feature.

The ECU 210, in addition to controlling the turn signal lamps 70, 80, 90 and 100 when hazard warning switch 180 is ON, also inhibits the operation of position lamp in headlamp assembly 40 and tail lamp assembly 45.

Thus from the above description, it should be clear that control of average voltage supplied to the turn signal lamps based on battery voltage will extend the battery service time which in turn enable good startability and better performance of the two-wheeler.

The system could be used for turn signal lamps with bulbs or LEDs (Light Emitting Diodes). The system also allows easy modification of an existing two-wheeler to accommodate hazard warning feature.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. A hazard warning system for a two wheeled vehicle comprising:

atleast a left and right turn signal lamps for indicating an intended turn to oncoming vehicles;

atleast a turn-signal-lamp switch assembly for switching ON/OFF the said turn signal lamps;

atleast a flasher for supplying pulsed voltage in order to cause the said turn signal lamps to blink at a predetermined frequency;

atleast a hazard warning switch for simultaneously operating the said left and right turn signal lamps to indicate a potential hazard to oncoming vehicles;

an ECU (Electronic Control Unit) for controlling the voltage applied to the said turn signal lamps when the said hazard warning switch is operated;

wherein the ECU controls the voltage applied to the said turn signal lamps based on battery voltage sensed in order to extend battery service time.

2. The hazard warning system as claimed in claim 1, wherein the said ECU modulates the said flasher output voltage with variable duty cycle based on the battery voltage sensed.

3. The hazard warning system as claimed in claim 1, wherein the said ECU selectively switches ON/OFF the said turn signal lamps based on the battery voltage sensed.

4. The hazard warning system as claimed in 1, wherein the said turn signal lampscomprises of bulbs.

5. The hazard warning system as claimed in 1, wherein the said turn signal lamps comprises of LEDs (Light Emitting Diodes).

6. The hazard warning system as claimed in 1, wherein the said ECU comprises of a microcontroller for sensing the battery voltage and for generating switching signals.

7. The hazard warning system as claimed in 1, wherein the said ECU is also used for engine control such as ignition.

8. The hazard warning system as claimed in 1 and claim 6, wherein the said ECU
comprises of electronic switches which connect the said flasher output voltage to the said turn signal lamps based on the said microcontroller switching signals.

9. The hazard warning system as claimed in 1, wherein the said two-wheeled vehicle is a" motorcycle.

10. The hazard warning system as claimed in 1, wherein the said two-wheeled vehicle is a scooter.

11. The hazard warning system as claimed in 1, wherein the said battery is of Lead Acid type.

12. The hazard warning system as claimed in 1, wherein the said ECU inhibits operation of a position lamp when the said hazard warning switch is ON.

13. The hazard warning system as claimed in 1, wherein the said ECU inhibits operation of a tail lamp when the said hazard warning switch is ON.