Power management system for a transport refrigeration unit

1. A vehicle ( 1 ) for transporting goods, the vehicle ( 1 ) comprising:

an axle ( 10 );

a transport refrigeration unit ( 3 ); and

a power management system ( 2 ) for supplying power to the transport refrigeration unit ( 3 );

wherein the power management system ( 2 ) comprises:

a generator ( 11 ) configured to be selectively coupled to an axle ( 10 ) of the vehicle ( 1 ), wherein the generator ( 11 ) is configured to generate electricity when coupled to the axle ( 10 ); and

a controller ( 20 ) configured to monitor a speed of the vehicle ( 1 ) and to selectively couple and decouple the generator ( 11 ) from the axle ( 10 );

wherein the controller ( 20 ) is configured to determine that the vehicle ( 1 ) is in a first state and decouple the generator ( 11 ) from the axle ( 10 ) when the vehicle ( 1 ) is in the first state, wherein the speed of the vehicle ( 1 ) is increasing in the first state; and

wherein the controller ( 20 ) is configured to determine that the vehicle ( 1 ) is in a second state and couple the generator ( 11 ) to the axle ( 10 ) when the vehicle ( 1 ) is in the second state, wherein the speed of the vehicle ( 1 ) is substantially constant in the second state.

2. A vehicle ( 1 ) as claimed in claim 1 , wherein the power management system ( 2 ) comprises an energy storage device ( 13 ), the energy storage device ( 13 ) being operable to power the transport refrigeration unit ( 3 ); and

wherein the generator ( 11 ) is configured to selectively recharge the energy storage device ( 13 ).

3. A vehicle ( 1 ) as claimed in claim 2 , wherein the controller ( 20 ) is configured to:

monitor a power demand of the transport refrigeration unit ( 3 ); and

monitor a power generation rate of the generator ( 11 ); and

if the power generation rate exceeds the power demand, power the transport refrigeration unit ( 3 ) and recharge the energy storage device ( 13 ) via the generator ( 11 ); and

if the power demand exceeds the generation rate, power the transport refrigeration unit ( 3 ) via the generator ( 11 ) and the energy storage device ( 13 ).

4. A vehicle ( 1 ) as claimed in claim 2 , wherein the controller ( 20 ) is configured to monitor a state-of-charge of the energy storage device ( 13 ); and

wherein the state-of-charge of the energy storage device ( 13 ) is less than a first threshold in the second state.

5. A vehicle ( 1 ) as claimed in claim 4 , wherein the controller ( 20 ) is configured to determine that the vehicle ( 1 ) is in a third state and decouple the generator ( 11 ) from the axle ( 10 ) when the vehicle ( 1 ) is in the third state, wherein the state-of-charge exceeds a second, higher threshold in the third state.

6. A vehicle ( 1 ) as claimed in claim 1 , wherein the vehicle ( 1 ) comprises a position determination device ( 25 ) configured to provide real-time location data for the vehicle ( 1 ); and

wherein the controller ( 20 ) is configured to receive the real-time location data from the position determination device ( 25 ) and determine a rate of change of speed of the vehicle ( 1 ) based on the real-time location data.

7. A vehicle ( 1 ) as claimed in claim 1 , wherein the controller ( 20 ) is configured to receive braking data for the vehicle ( 1 ); and

wherein the controller ( 20 ) is configured to determine that the vehicle ( 1 ) is in a fourth state and couple the generator ( 11 ) to the axle ( 10 ) when the vehicle ( 1 ) is in the fourth state, wherein the vehicle ( 1 ) is braking in the fourth state.

8. A vehicle ( 1 ) as claimed in claim 1 ,

wherein the speed of the vehicle ( 1 ) is above a minimum speed for generating electricity in the second state; and

wherein the controller ( 20 ) is configured to decouple the generator ( 11 ) from the axle ( 10 ) when the speed of the vehicle is less than the minimum speed for generating electricity.

9. A tractor-trailer system ( 100 ) for transporting goods, the tractor-trailer system ( 100 ) comprising:

a tractor ( 4 ) for driving a trailer ( 1 ); and

the trailer ( 1 ), wherein the trailer ( 1 ) is a vehicle as claimed in claim 1 .

10. A tractor-trailer system ( 100 ) as claimed in claim 9 , wherein the tractor ( 4 ) comprises an engine management system ( 5 ), the engine management system ( 5 ) comprising a plurality of sensors configured to monitor one or more operational parameters of the tractor ( 4 ); and

wherein the controller ( 20 ) is configured to receive the one or more of the operational parameters from the engine management system ( 5 ) and to determine a state of the trailer ( 1 ) based on the operational parameters.

11. A tractor-trailer system ( 100 ) as claimed in claim 10 , wherein the one or more operational parameters include a brake pedal position; and

wherein the controller ( 20 ) is configured to determine that the trailer ( 1 ) is in a fourth state and couple the generator ( 11 ) to the axle ( 10 ) when the trailer ( 1 ) is in the fourth state, wherein the brake pedal is depressed in the fourth state.

12. A tractor-trailer system ( 100 ) as claimed in claim 10 , wherein the one or more operational parameters include a brake pedal position; and

wherein the controller ( 20 ) is configured to determine that the trailer ( 1 ) is in a fifth state and decouple the generator ( 11 ) from the axle ( 10 ) when the trailer ( 1 ) is in the fifth state, wherein the trailer ( 1 ) is decelerating and the brake pedal is not depressed in the fifth state.

13. A tractor-trailer system ( 100 ) as claimed in claim 10 , wherein the engine management system ( 5 ) is in wireless communication with the power management system ( 2 ).

14. A tractor-trailer system ( 100 ) as claimed in claim 13 , wherein the trailer ( 1 ) comprises a first wireless module ( 31 ) in communication with the power management system ( 2 );

wherein the tractor ( 4 ) comprises a second wireless module ( 32 ) in communication with the engine management system ( 5 ); and

wherein the first wireless module ( 31 ) and the second wireless module ( 32 ) are configured to automatically connect when the trailer ( 1 ) is attached to the tractor ( 4 ).

15. A method of operating a power management system ( 2 ) for powering a transport refrigeration unit ( 3 ), the method comprising:

monitoring a speed of a vehicle ( 1 ) comprising an axle ( 10 ), the power management system ( 2 ) and the transport refrigeration unit ( 3 );

determining that the vehicle ( 1 ) is in a first state and decoupling a generator ( 11 ) from the axle ( 10 ) when the vehicle ( 1 ) is in the first state, wherein the speed of the vehicle ( 1 ) is increasing in the first state; and

determining that the vehicle ( 1 ) is in a second state and coupling the generator ( 11 ) to the axle ( 10 ) when the vehicle ( 1 ) is in the second state, wherein the speed of the vehicle ( 1 ) is constant in the second state.