Refrigerated cargo vehicle with alternator driven refrigeration system
A refrigerated cargo vehicle has a refrigerated enclosure and a refrigeration system that delivers a refrigerated air flow to the enclosure. The refrigeration system includes a compressor that has a voltage rating higher than the electric potential output of an alternator driven by an engine of the refrigerated cargo vehicle. A DC-to-DC power converter is disposed electrically between the alternator and the compressor so that the power converter receives electric current from the alternator at a first electric potential and outputs a second electric current to the compressor at a second electric potential higher than the first electric potential.
1 . A refrigerated cargo vehicle, comprising:
a chassis and body assembly defining an engine compartment and a cargo enclosure;
a plurality of wheels attached to the chassis and body assembly at a forward end thereof,
a plurality of wheels attached to the chassis and body assembly at a rearward end thereof;
an engine mounted to the chassis and body assembly at the engine compartment;
an alternator operatively connected to the engine so that the alternator outputs first electric current when the alternator is driven by the engine;
a refrigeration system, the refrigeration system comprising:
a refrigerant path;
a compressor mounted on the chassis and body assembly and located in the refrigerant path and configured to pump refrigerant located in the refrigerant path so that the refrigerant flows through the refrigerant path;
a condenser mounted in the chassis and body assembly and located in the refrigerant path;
a first fan disposed on the chassis and body assembly with respect to the condenser to move first air in a first air flow across the condenser so that the condenser transfers heat to the first air from refrigerant in the refrigerant path that moves through the condenser;
an evaporator mounted on the chassis and body assembly and located in the refrigerant path;
a second fan disposed on the chassis and body assembly with respect to the evaporator to move second air in a second air flow across the evaporator so that the evaporator transfers heat from the second air to the refrigerant in the refrigerant path that moves through the evaporator and so that the second air flows in the cargo enclosure from the evaporator; and
a first DC-to-DC power converter disposed electrically between the alternator and the compressor so that the first DC-to-DC power converter receives the first electric current from the alternator at a first electric potential and outputs second electric current to the compressor and wherein the first DC-to-DC power converter is configured to output the second electric current at a second electric potential higher than the first electric potential; and
a control system configured to operate the refrigeration system, wherein the control system comprises one or more controllers and computer-executable instructions that, when executed by the one or more controllers, cause the refrigeration system to supply conditioned air at a temperature between −10° F. and 45° F. at an ambient temperature of the refrigerated cargo vehicle when the engine is at idle solely based on the first electric current generated by the alternator and received at the first DC-to-DC power converter.
2 . The refrigerated cargo vehicle as in claim 1 , wherein
the alternator is configured to output, when driven by the engine, the first electric current at an electric potential in the range of about 12 VDC to about 14 VDC,
the compressor has a voltage rating that is greater than 14 VDC and less than 50 VDC, and
the second electric potential is at least as high as the compressor voltage rating.
3 . The refrigerated cargo vehicle as in claim 1 , wherein the first DC-to-DC power converter is a solid state switched mode power supply.
4 . The refrigerated cargo vehicle as in claim 3 , wherein the first DC-to-DC power converter has an electrical efficiency of at least 85% and a permanent magnet motor of the compressor has an electrical efficiency of at least 85%.
5 . The refrigerated cargo vehicle as in claim 1 , comprising an AC-to-DC power supply mounted on the chassis and body assembly and having an input terminal configured to connect to an AC power source that is independent of the refrigerated cargo vehicle and an output of electric current electrically connected to an input of the first DC-to-DC power converter so that the AC-to-DC power supply provides electric current to the first DC-to-DC power converter.
6 . The refrigerated cargo vehicle as in claim 1 , comprising a battery mounted on the chassis and body assembly and having an output of fourth electric current at an electric potential that is approximately at or below the first electric potential, wherein the battery is electrically connected to an input of the first DC-to-DC power converter so that the battery outputs the fourth electric current to the first DC-to-DC power converter.
7 . The refrigerated cargo vehicle as in claim 1 , comprising a battery mounted on the chassis and body assembly, wherein the battery is connected to an electrical output of at least one solar panel mounted on a roof of the refrigerated cargo vehicle and is electrically connected to an input of the first DC-to-DC power converter so that the battery provides electric current to the first DC-to-DC power converter.
8 . The refrigerated cargo vehicle as in claim 1 , wherein each of the first fan and the second fan has a voltage rating of about 12 VDC, and wherein the first DC-to-DC power converter is not disposed electrically between the alternator and either of the first fan or the second fan, such that each of the first fan and the second fan receive the first electric current from the alternator.
9 . The refrigerated cargo vehicle as in claim 1 , wherein the control system is configured to control the compressor of the refrigeration system to operate at a reduced capacity if the control system detects a low output voltage at a battery of the refrigerated cargo vehicle.
10 . A refrigerated cargo vehicle, comprising:
a chassis and body assembly defining an engine compartment and a cargo enclosure;
a plurality of wheels attached to the chassis and body assembly at a forward end thereof;
a plurality of wheels attached to the chassis and body assembly at a rearward end thereof;
an engine mounted to the chassis and body assembly at the engine compartment;
an alternator operatively connected to the engine so that the alternator outputs first electric current at an electric potential in the range of about 12 VDC to about 14 VDC when the alternator is driven by the engine;
a refrigeration system, the refrigeration system comprising:
a refrigerant path;
a rotary compressor with a permanent magnet motor having a voltage rating that is greater than 14 VDC and less than 50 VDC mounted on the chassis and body assembly and located in the refrigerant path and configured to pump refrigerant located in the refrigerant path so that the refrigerant flows through the refrigerant path;
a condenser mounted in the chassis and body assembly and located in the refrigerant path;
a first fan disposed on the chassis and body assembly with respect to the condenser to move first air in a first air flow across the condenser so that the condenser transfers heat to the first air from refrigerant in the refrigerant path that moves through the condenser;
an evaporator mounted on the chassis and body assembly and located in the refrigerant path;
a second fan disposed on the chassis and body assembly with respect to the evaporator to move second air in a second air flow across the evaporator so that the evaporator transfers heat from the second air to the refrigerant in the refrigerant path that moves through the evaporator and so that the second air flows in the cargo enclosure from the evaporator; and
a first DC-to-DC power converter comprising a solid state switched mode power supply disposed electrically between the alternator and the compressor so that the first DC-to-DC power converter receives the first electric current from the alternator at a first electric potential and outputs second electric current to the compressor and wherein the first DC-to-DC power converter is configured to output the second electric current at a second electric potential that is higher than the first electric potential and at least as high as the voltage rating of the compressor, and
a control system configured to operate the refrigeration system, wherein the control system comprises one or more controllers and computer-executable instructions that, when executed by the one or more controllers, cause the refrigeration system to provide conditioned air at a temperature between −10° F. and 45° F. at an ambient temperature of the refrigerated cargo vehicle when the engine is at idle solely based on the first electric current generated by the alternator and received at the first DC-to-DC power converter.
11 . The refrigerated cargo vehicle as in claim 10 , wherein the first DC-to-DC power converter has an electrical efficiency of at least 85% and the permanent magnet motor has an electrical efficiency of at least 85%.
12 . The refrigerated cargo vehicle as in claim 10 , comprising an AC-to-DC power supply mounted on the chassis and body assembly and having an input terminal configured to connect to an AC power source that is independent of the refrigerated cargo vehicle and an output of electric current electrically connected to an input of the first DC-to-DC power converter so that the AC-to-DC power supply provides electric current to the first DC-to-DC power converter.
13 . The refrigerated cargo vehicle as in claim 10 , comprising a battery mounted on the chassis and body assembly and having an output of fourth electric current at an electric potential that is approximately at or below the first electric potential, wherein the battery is electrically connected to an input of the first DC-to-DC power converter so that the battery outputs the fourth electric current to the first DC-to-DC power converter.
14 . The refrigerated cargo vehicle as in claim 10 , comprising a battery mounted on the chassis and body assembly, wherein the battery is connected to an electrical output of at least one solar panel mounted on a roof of the refrigerated cargo vehicle and is electrically connected to an input of the first DC-to-DC power converter so that the battery provides electric current to the first DC-to-DC power converter.
15 . The refrigerated cargo vehicle as in claim 10 , wherein each of the first fan and the second fan has a voltage rating of about 12 VDC, and wherein the first DC-to-DC power converter is not disposed electrically between the alternator and either of the first fan or the second fan, such that each of the first fan and the second fan receive the first electric current from the alternator.
16 . The refrigerated cargo vehicle as in claim 10 , wherein the control system is configured to control the rotary compressor of the refrigeration system to operate at a reduced capacity if the control system detects a low output voltage at a battery of the refrigerated cargo vehicle.