Electric vehicle pedestrian warning system

1. A pedestrian warning system for an electric vehicle, comprising:

an encapsulating container disposed in a location of the electric vehicle that is exterior to an interior cabin of the electric vehicle;

a speaker affixed to an interior portion of the encapsulating container;

an amplifier coupled to the speaker;

a computer processor communicatively coupled to the amplifier and a vehicle network; and

logic executable by the computer processor, the logic configured to transmit a sound file to the speaker through the amplifier over the vehicle network upon activation of the electric vehicle, the sound file comprising a pedestrian warning sound;

wherein a first portion of the pedestrian warning sound is output by the speaker and amplified using acoustical properties of the encapsulating container, the first portion of the pedestrian warning sound amplified in a low frequency range capable of being cancelled by an active noise cancellation system that is located in the interior cabin and coupled to the vehicle network.

2. The system of claim 1 , wherein a length of the encapsulating container is determined as a function of a target low frequency range of the pedestrian warning sound.

3. The system of claim 1 , wherein a first end of the encapsulating container is open and a second end of the encapsulating container is closed.

4. The system of claim 3 , wherein the speaker is disposed at the second end of the encapsulating container and facing toward the open end.

5. The system of claim 3 , wherein acoustic resonant frequencies of sound for the encapsulating container are determined by:

f

n

=

n

⁢

⁢

c

4

⁢

⁢

L

where f n , is the acoustic resonant frequencies of the encapsulating container; n=1, 3, 5, . . . ; c represents speed of sound in air (353 m/s); and L is a length of the encapsulating container.

6. The system of claim 1 , the first portion of the pedestrian warning sound is broadcast at the speaker at a frequency below 400 Hz.

7. The system of claim 1 , wherein the first portion of the pedestrian warning sound is amplified by the acoustical properties of the encapsulating container in the low frequency range.

8. The system of claim 1 , wherein a second portion of the pedestrian warning sound is transmitted at a high frequency range above or equal to 400 Hz.

9. The system of claim 1 , wherein the encapsulating container is configured to have a cylindrical shape.

10. The system of claim 1 , wherein the speaker is configured to be approximately 65 mm in diameter, and 30 mm in thickness, with a power of 1 Watt.

11. The system of claim 1 , further comprising an end treatment affixed to the open end of the encapsulating container, the end treatment angled approximately 30 degrees to 45 degrees with respect to an axis along the length of the encapsulating container, the axis extending lengthwise with respect to a length of the electric vehicle;

wherein an angle of the end treatment directs the second portion of the pedestrian warning sound away from the electric vehicle.

12. The system of claim 1 , wherein a first end of the encapsulating container is open and a second end of the encapsulating container is open.

13. The system of claim 12 , wherein the speaker is disposed at one of the first end and the second end.

14. The system of claim 12 , wherein acoustic resonant frequencies of sound for the encapsulating container are determined by:

f

n

=

n

⁢

⁢

c

2

⁢

L

where f n , is the acoustic resonant frequencies of the encapsulating container; n=1, 2, 3, . . . ; c represents speed of sound in air (353 m/s); and L is a length of the encapsulating container.

15. A pedestrian warning system for an electric vehicle, comprising:

a vehicle structural rail disposed in an underbody of the electric vehicle;

a speaker affixed to an interior portion of the vehicle structural rail;

an amplifier coupled to the speaker;

a computer processor communicatively coupled to the amplifier and a vehicle network; and

logic executable by the computer processor, the logic configured to transmit a sound file to the speaker through the amplifier over the vehicle network upon activation of the electric vehicle, the sound file comprising a pedestrian warning sound;

wherein a first portion of the pedestrian warning sound is output by the speaker and amplified using acoustical properties of the vehicle structural rail, the first portion of the pedestrian warning sound amplified in a low frequency range capable of being cancelled by an active noise cancellation system that is located in the interior cabin and coupled to the vehicle network.

16. The system of claim 15 , wherein the vehicle structural rail is partitioned by a baffle at a location internal to the vehicle structural rail to define a length, the length determined as a function of a target low frequency range of the pedestrian warning sound.

17. The system of claim 15 , wherein the first portion of the pedestrian warning sound is broadcast at the speaker at a frequency below 400 Hz.

18. The system of claim 15 , wherein the first portion of the pedestrian warning sound is amplified by the acoustical properties of the vehicle structural rail in the low frequency range.

19. The system of claim 15 , wherein a second portion of the pedestrian warning sound is transmitted at a high frequency range above or equal to 400 Hz.

20. The system of claim 15 , further comprising an end treatment affixed to the open end of the vehicle structural rail, the end treatment angled approximately 30 degrees to 45 degrees with respect to an axis along the length of the vehicle structural rail as defined by baffle, the axis extending lengthwise with respect to a length of the electric vehicle;

wherein an angle of the end treatment directs the second portion of the pedestrian warning sound away from the electric vehicle.