Vehicle auxiliary power unit, assembly, and related methods

• US 7,259,469 B2
• Filed: 08/02/2004
• Issued: 08/21/2007
• Est. Priority Date: 07/31/2003
• Status: Expired due to Fees

• Current Assignee: Longhorn SCSF, Ltd., Mobile Climate Control Corp.
• Original Assignee: Scs Frigette
• Inventors: Shields, Neal G., Brummett, Keiv, Pannell, Bobby L.
• Primary Examiner(s): Schuberg; Darren
• Assistant Examiner(s): Cuevas; Pedro J.
• Application Number:
  US10/909,829
• Publication Number:
  US 20050035657A1
• Time in Patent Office: 1,114 Days
• Field of Search: 290/1.A, 290/40.C, 165/42, 165/202
• US Class Current: 290/40.00C
• CPC Class Codes: B60H 1/3226 Self-contained devices, i.e. including own drive motor
• CPC Class Codes: B60H 1/3232 particularly adapted for load transporting vehicles B60H1/3226 takes precedence
• CPC Class Codes: F02B 63/04 for electric generators
• CPC Class Codes: F02B 63/06 for pumps

Abstract

A truck includes an auxiliary power unit having components specifically selected such that they form a stand-alone unit that can fit within an auxiliary compartment of a vehicle and deliver heating, cooling, and additional electric power to the vehicle. Included is an auxiliary engine, an auxiliary alternator, and an auxiliary condenser to provide coolant for a personnel compartment mounted evaporator. An auxiliary voltage regulator provides a ramp-up feature to minimize excessive start-up loads, limits maximum available current from the auxiliary alternator when the auxiliary compressor is engaged, and selectively disables power to electrical components in the event of low vehicle battery voltage. The auxiliary engine includes a radiator system to provide heated fluid for a personnel compartment mounted heat exchanger.

Claims

1. A truck, comprising:

a personnel compartment;

a main engine and a main battery;

an external auxiliary compartment connected to an exterior portion of the truck; and

an auxiliary power unit assembly positioned in the external auxiliary compartment of the truck, the auxiliary power unit including;

an auxiliary engine,

an auxiliary alternator positioned adjacent to and powered by the auxiliary engine, to provide DC electric power, the auxiliary alternator being electrically connected with the main battery to charge the main battery while the main engine is off,

an inverter electrically connected to the auxiliary alternator to convert the DC electric power from the auxiliary alternator to AC electric power for powering at least one AC electrical component, and

an auxiliary voltage regulator electrically connected to the auxiliary alternator to control voltage and amperage generated by the auxiliary alternator, the auxiliary voltage regulator-configured to sense voltage of the main battery to selectively disable the inverter if the voltage of the main battery drops below a selected level, and to sense RPM of the auxiliary engine during start-up to allow auxiliary engine speed to obtain a minimum selected speed prior to enabling application of an electrical load to the auxiliary alternator.

2. The truck as defined in claim 1, further comprising a DC block heater electrically connected to the main battery, the voltage regulator selectively disabling the block heater in the event the voltage of the main battery drops below a selected level.

3. The truck as defined in claim 1, further comprising:

an air conditioner compressor driven by the auxiliary engine; and

an air conditioner condenser mounted to the auxiliary compartment for providing cooling air for the personnel compartment.

4. The truck as defined in claim 1, further comprising an auxiliary air conditioner compressor driven by the auxiliary engine, and wherein the voltage regulator limits maximum available current from the auxiliary alternator when the auxiliary compressor is engaged to avoid overloading the auxiliary engine.

5. The truck as defined in claim 2, wherein after disabling the block heater when the voltage of the battery decreased below a first preselected voltage, the voltage regulator enables power back to the block heater when the voltage of the battery exceeds a second preselected voltage, the second preselected voltage being higher than the first preselected voltage.

6. The truck as defined in claim 5, wherein after disabling the inverter, the voltage regulator enables power back to the inverter when the voltage of the battery exceeds the second preselected voltage.

7. The truck as defined in claim 1,

wherein the auxiliary power unit assembly further comprises:

an auxiliary condenser mounted to the auxiliary compartment,

an auxiliary compressor positioned adjacent to and powered by the auxiliary engine, to provide coolant to the auxiliary condenser, and

an auxiliary fan in the auxiliary compartment to provide cooling air to the auxiliary condenser when the auxiliary compressor is driven by the auxiliary engine; and

wherein the truck further comprises;

an auxiliary evaporator to provide cool air to the vehicle personnel compartment, and

an auxiliary refrigerant line connecting the auxiliary condenser with the auxiliary evaporator to provide refrigerant from the auxiliary condenser to the auxiliary evaporator.

8. The truck as defined in claim 1,

wherein the auxiliary power unit assembly further comprises:

an auxiliary radiator mounted to the auxiliary compartment for cooling coolant fluid of the auxiliary engine, and

a DC electrical auxiliary fan in the auxiliary compartment to selectively provide cooling air to the auxiliary radiator when a temperature of the engine coolant fluid exceeds a preselected temperature; and

wherein the truck further comprises;

an auxiliary heat exchanger to heat air for the personnel compartment, and

a heating line to connect the auxiliary heat exchanger with the auxiliary radiator to provide heated fluid from the auxiliary engine to the auxiliary heat exchanger.

9. The truck defined in claim 8, wherein the auxiliary fan is not powered to cool the auxiliary engine when the temperature of the engine coolant fluid is below a preselected temperature.

10. A truck comprising:

a personnel compartment;

a main engine and a main battery;

a DC block heater electrically connected to the main battery;

an external auxiliary compartment connected to an exterior portion of the truck; and

an auxiliary power unit assembly positioned in the external auxiliary compartment of the truck, the auxiliary power unit including;

an auxiliary engine,

an air conditioner compressor driven by the auxiliary engine,

an air conditioner condenser mounted to the auxiliary compartment for providing cooling air for the personnel compartment,

an auxiliary alternator positioned adjacent to and powered by the auxiliary engine, to provide DC electric power, the auxiliary alternator being electrically connected with the main battery to charge the main battery while the main engine is off,

an inverter electrically connected to the auxiliary alternator to convert the DC electric power from the auxiliary alternator to AC electric power for powering at least one AC electrical component, and

an auxiliary voltage regulator electrically connected to the auxiliary alternator to control voltage and amperage generated by the auxiliary alternator, the auxiliary voltage regulator configured to sense voltage of the main battery to selectively disable the block heater in the event the voltage of the main battery drops below a first selected level and to selectively disable the inverter if the voltage of the main battery drops below a second selected level, and to sense RPM of the auxiliary engine during start-up to allow auxiliary engine speed to obtain a minimum preselected speed prior to enabling application of an electrical load to the auxiliary alternator.

11. The truck as defined in claim 10, wherein the voltage regulator limits maximum available current from the auxiliary alternator when the auxiliary compressor is engaged to avoid overloading the auxiliary engine.

12. A method of power regulation of an auxiliary power unit assembly for a truck having a main engine and main battery, the auxiliary power unit being mounted to the truck and having an auxiliary engine and an auxiliary alternator driven by the auxiliary engine, the method comprising the steps of:

(a) operating the auxiliary engine while the main engine is off, thereby generating DC voltage with the auxiliary alternator, sensing engine speed of the auxiliary engine during start-up to allow the engine speed to obtain a minimum selected speed prior to enabling the auxiliary alternator;

(b) applying a charging voltage from the auxiliary alternator to the main battery;

(c) converting some of the DC voltage to AC voltage and powering an AC electrical component; and

(d) ceasing to power the AC electrical component if the main battery voltage drops below a selected minimum.

13. The method as defined in claim 12, further comprising the step of:

powering an air conditioner compressor with the auxiliary engine; and

wherein step (a) further comprises limiting maximum available current from the auxiliary alternator when the auxiliary compressor is being driven to avoid overloading the auxiliary engine.

14. The method as defined in claim 12, further comprising the steps of:

providing DC power from the main battery to a block heater;

disabling power to the block heater if the main battery voltage drops below the selected minimum; and

enabling power to the block heater, after being disabled, when the battery voltage exceeds a second selected voltage, the second selected voltage being higher than the selected minimum.