Abstract:
The invention is a Battery-Operated Auxiliary Power Unit that adds an independent supplementary heating and air conditioning system to a truck&#39;s sleeping quarters that is capable of controlling the temperature of the sleeper compartment during the off period without running his truck motor and creating needless pollution.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    None. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
       [0002]    None. 
       THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    None. 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
       [0004]    None. 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    Vehicle-mounted tractor cab-heating systems. 
         [0007]    2. Background Art 
         [0008]    Truck drivers taking loads over long distances often sleep in their truck&#39;s sleeper compartment during their off period. The trucks employ one heating and cooling system to control the temperature in the front cabin where the driver sits, and an entirely different system for the sleeping compartment, or “sleeper” section. Both of these systems are powered by the trucks diesel engine. 
         [0009]    Semi-trucks typically have four 12V batteries to run all electrical systems and crank the truck&#39;s diesel engine. While the truck&#39;s engine is operating, trucks have an alternator (typically around 130 A) that keeps the batteries charged, and provides sufficient power for operation of all the trucks electric systems. However, federal law prohibits commercial truck operators from driving longer than eleven hours out of a 24 14-hour period and then they must have a 10-hour off period, of which 8 hours must be spent inside the sleeper compartment. During the off-period the operator must get sleep and have somewhere to spend their time. The only way for the trucker to power the heat and air conditioning systems of a stock truck is to run the diesel drive motor. 
         [0010]    However, running the diesel drive motor all night has severe repercussions. Truck motors consume about a gallon of diesel fuel per hour to idle at night in order to keep the sleeper compartment warm in cold weather by circulating antifreeze through the heater core. A blower fan circulates the air through the trucks sleeper compartment&#39;s ductwork. In order to keep the cabin cool in hot weather, operators must run the diesel drive motor to power the air conditioning system. Idling the drive motor during these prolonged periods is uneconomical, as it shortens the life of the motor and costs upwards of $40.00 per day (assuming $4.00 per gallon and a 10-hour off-period, in 2012 pricing). 
         [0011]    With today&#39;s focus on environmental concerns, many regulations are being developed to prohibit the inefficient and smog producing practice of all-night idling, leading the trucking industry to seek cost efficient systems to provide off-period heat and air conditioning in the sleeper compartment. The market is attempting to answer this need. The following systems have been developed or patented for that purpose. 
         [0012]    Battery-Powered Heaters are common in the art today, as disclosed in U.S. Pat. Nos. 5,497,941, 5,884,007, 6,040,561, 7,007,856, 7,380,586, 7,410,415, 7,707,845 and 7,870,892. In these systems, a vehicle&#39;s battery is the power source for a heating system to maintain a minimum temperature in a truck cabin. The battery provides power for a hearing element and fan, along with the control circuitry. The struggle with these systems is that, if operated for prolonged periods of time, they can drain the battery and leave the vehicle unable to start. 
         [0013]    Engine-Based Systems are also common, as discussed in U.S. Pat. Nos. 5,571,432, and 6,237,357. These systems require the vehicle motor to provide power or heat, which is then distributed. The obvious down side to these systems is that they are highly inefficient, because the vehicle engine (typically 400 to 500 horsepower diesel motors) must be running during all non-driving periods. There are also systems, which use another small diesel motor to heat the antifreeze and turn a secondary air conditioning compressor. These systems add another engine to maintain cabin temperature. These motors burn about a gallon of diesel every four hours, which will cost around $10.00 per day (assuming $4.00 per gallon of diesel and 2.5 gallons of diesel per 10-hour off-period). These systems work but do not provide sufficient heat in comparison with traditional large motor units and unnecessarily duplicate the entire heating and cooling systems of a stock trucks sleeper compartment. 
         [0014]    Auxiliary Generator Systems are the third method identified, as discussed in U.S. Pat. Nos. 4,762,170, 4,825,663, and 6,232,679, in which a small generator provides power to heaters and other devices within a cabin while the main engine is not running. This approach eliminates the wasteful idling of the main engine-based systems, as well as the dead battery that can result from battery-based heating systems. These auxiliary generator-based systems are complicated and prone to failure and require a second diesel engine, which must be maintained and requires diesel fuel to operate. These systems use around $10.00 per day of diesel fuel also. 
         [0015]    Other Solutions include battery-operated Heat Pumps. These 120 Vac units require a power inverter to convert the vehicle&#39;s 12 Vdc power to 120 Vac, which can lose more than 10% of its delivered power during conversion. The blower fan is directed through the hot or cold side of the ‘box’ to circulate hot or cold air. They too work but do not provide the kind of heat that the diesel motor can deliver. 
         [0016]    These systems show that vehicle cabin temperature control is an ongoing challenge that has had multiple solutions presented, and each has its own benefits and costs. What the industry needs is a system that can provide heat and air conditioning for the sleeper compartment when the vehicle motor is off, but does not drain the vehicle&#39;s primary battery pack and thus endanger the operator&#39;s ability to start the vehicle in the morning. 
         [0017]    Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations pointed out in the appended claims. 
       BRIEF SUMMARY OF THE INVENTION 
       [0018]    The invention disclosed is a Battery-Operated Auxiliary Power Unit that provides supplementary temperature control of a vehicle cabin. The invention allows a commercial truck driver to control the temperature of the truck&#39;s sleeper compartment during the off-period without running the truck motor and creating needless pollution. 
         [0019]    The APU  11  comprises: Batteries  103  configured in an Auxiliary Battery Pack (ABP)  131  installed in Battery Box  135 , Heating Element Assembly  109 , Circulation Pump  107 , Temperature Sending Unit  111 , Filler Neck  113 , Stock Compressor  115 , Drive Motor  105 , optional Electric Condenser  117 , Evaporator  119 , Heater Core  125 , optional Alternator  121  to charge the ABP  131 , the truck&#39;s standard battery pack, and optional Mineral Oil  140  as the heating fluid. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0020]      FIG. 1  is a block diagram of the invention. Items in dotted lines indicate components that are standard equipment on modern trucks. 
           [0021]      FIG. 2  is a top view of the ABP  131  installed in the Battery Box  135 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    As represented in  FIG. 1 , the Battery-Operated Auxiliary Power Unit (“APU”)  11  provides supplementary temperature control of a vehicle cabin using an additional independent air conditioning and heating system, The system is powered by an auxiliary battery pack (ABP  131 ) at night without placing a load on the regular truck batteries, but is sufficiently charged by an alternator while the operator is driving during a normal shift. 
         [0023]    The APU  11  comprises: Batteries  103  configured in an Auxiliary Battery Pack (ABP)  131  and installed in Battery Box  135 , Heating Element Assembly  109 , Circulation Pump  107 , Temperature Sending Unit  111 , Filler Neck  113 , Stock Compressor  115 , Drive Motor  105 , optional Electric Compressor  117 , optional Alternator  121  to charge the ABP  131 , and optional Mineral Oil  140  as the heating fluid. 
         [0024]    The ABP  131  is a battery pack that can be configured any number of ways, but as currently designed, the ABP  131  comprises four deep-cycle Batteries  103  connected in parallel to provide a 12V, 1000 A-hr, ten-hour power source. The ABP  131  is installed in a frame-mounted Battery Box  135 , as shown in  FIG. 2 . 
         [0025]    The Battery Box  135  is mounted between the frame rails behind the sleeper cabin and in front of the fifth-wheel trailer hitch. All semi trucks have this space available with no other equipment mounted in this location. The current design places half the batteries on each side of the ABP  13 , leaving the center section of the box open for installation of other equipment, such as a relocated A/C Stock Compressor  115  and Drive Motor  105 , or a completely new Electric Compressor  117 . 
         [0026]    As previously discussed, the truck&#39;s stock four batteries will remain in use and are not part of the APU  11 . These truck batteries require a 130-amp alternator to keep them property charged. Federal law prohibits commercial operators from driving longer than eleven hours of a 14-hour period, so with the four additional batteries comprising the ABP  131 , the truck&#39;s alternator must be able to fully charge all eight batteries while the truck is running down the road in an eleven-hour driving period, such that the ABP  131  has sufficient power to supply the heating/AC system, and any other electronic devices during the off-period. In practice, the inventor has determined that the system will function well when the Alternator  121  can provide 250 A of charging current to the two sets of battery packs. However, this replacement may not be necessary, depending upon the ambient temperature where the truck is operating and other conditions. 
         [0027]    This APU will not replace the truck&#39;s front cabin heater. The front cabin heater will still provide front cabin heat and windshield defrosting functions. These two functions will only be required while the truck is driving down the road, so the APU  11  will not need to interfere with this bullet-proof system. 
         [0028]    The APU  11  includes Heating Element Assembly  109  and the magnetic-driven impeller Circulation Pump  107  for sleeper cabin heating. The Heating Element Assembly  109 , as currently designed, uses two 20 W heating elements, and is mounted inside the heating fluid reservoir which is plumbed directly into the heater core and in line with the circulation pump. This entire assembly is mounted in a housing with the attached blower fan, which is connected to the sleeper compartments ductwork. This assembly is typically located under the bed, inside the sleeper compartment and is not connected to the trucks drive motor cooling system. 
         [0029]    In operation, the Heating Element Assembly  109  and magnetic-driven impeller Circulation Pump  107  are mounted in this housing to distribute heated mineral oil through the heater core. The stock blower fan is also mounted to the top of this housing, which circulates the hot air from inside the housing throughout the sleeper compartment via stock truck ductwork and this in turn heats the sleeper compartment. The new system continues to use the stock housing, heater core, ductwork and blower fan. The 12 V pump is rated continuous duty and uses magnetic power to turn the impeller. The impeller is not connected but floats freely in the pump casing. This means no leaking through a seal since there is no driveshaft connecting the pump motor and the impeller. 
         [0030]    As shown in  FIG. 3 , the Heating Element Assembly is controlled as follows:
       a) A user activates the heating operation through the use of the truck&#39;s stock temperature controller, which energizes the Heating Element Assembly  109 , consisting of two 20 W resistive heating elements (both are energized to bring system to operating temperature and only one element is required to maintain operating temperature), and the Circulation Pump  107 . The Pump  107  continuously circulates the heating fluid while the heating system operates.   b) The Temperature Sending Unit  111  provides a temperature reading for the truck&#39;s stock temperature controller, which deactivates the second heating element through the use of a solenoid (normally open switch) when the Mineral Oil  140  (or whatever heating fluid is employed in the system) reaches a preset maximum setting. The solenoid changes state again (closing the switch) to reenergize the second heating element if the temperature of the Oil  140  lowers to the preset minimum setting.   c) Throughout the heating cycle, the Circulation Pump  107  circulates the heated oil through the stock heater core and the oil reservoir (which houses the dual heating elements).   d) The user ceases operation through the use of the truck&#39;s built-in temperature controller, thus de-energizing the Pump  107  and Heating Element Assembly  109 .       
 
         [0035]    Typical vehicle heating systems circulate water or an antifreeze through a heater core, but this invention optionally uses Mineral Oil  140  instead of antifreeze, because it has a higher boiling point than antifreeze or water and is noncorrosive. The Mineral Oil  140  circulates through the heater core with the use of the Circulation Pump  107 . The Mineral Oil  140  is added to the system through Filler Neck  113 , and circulated through the heater core and is heated with the Heating Element Assembly  109  (instead of the diesel engine) and pumped through the heater core and copper piping which houses the Heating Element Assembly  109  and Circulation Pump  107 . This entire heating system is mounted inside the truck&#39;s standard housing (typically mounted under the bed) and is not connected in any way to the diesel engine&#39;s cooling system. 
         [0036]    The air conditioning system is an optional element of the APU  11 . Though the discussion assumes that the Stock Compressor  115  is moved from the engine compartment to the Battery Box  135  and powered by a Drive Motor  105 , the invention includes multiple configurations. The air conditioning function of the APU  11  can provide air conditioning for the front cabin and the sleeper compartment. The invention could be a retro-fit to a stock truck, or could be a manufacturer option. The invention can be installed and configured in at least two different ways, including: 
         [0037]    a) Two Compressor Option—two different A/C compressors, the engine-connected Stock Compressor  115  and a separate 12V Electric Motor Driven Compressor  117  installed in the Battery Box  135  driven by the ABP  131 ; or 
         [0038]    b) Relocation Option—the single stock A/C Stock Compressor  115  moved to the ABP Battery Box  135  and driven by a Drive Motor  105 . 
         [0039]    The preferred approach is to relocate the Stock Compressor  115  from the diesel engine where it is typically belt-driven in the engine compartment under the hood of the truck, to the center section of the Battery Box  135  and driven by a 12V electric Drive Motor  105 . The same housing which holds the stock heater core and blower fan also hold the truck&#39;s stock evaporator core for air conditioning the sleeper compartment. 
         [0040]    In operation, a user controls the A/C portion of the system (through the use of the truck&#39;s temperature controller unit), which energizes the 12V electric Drive Motor  107 , which turns the A/C compressor  115  to increase the pressure of the refrigerant. The only unique part of this system is the use of the Drive Motor  107  to operate the compressor. As in most traditional A/C systems, when the refrigerant enters the evaporator the tubing size is increased which causes a rapid cooling of the refrigerant and the evaporator core as well. The sleeper compartment air is circulated through the housing (via the use of the blower fan and ductwork) where cold air is created and thus cools the sleeper compartment. 
         [0041]    While this invention has been described as it is currently built, the invention is not limited to the disclosed embodiments, but can be employed in various equivalent arrangements included within the spirit and scope of the claims.