Abstract:
A rotatable electrically actuated valve having a spindle with axially spaced grooves and lands constructed and arranged to selectively connect an auxiliary air conditioning system to a truck cab while isolating the truck air conditioning system, and for connecting the truck air conditioning system to the truck cab, while isolating the auxiliary air conditioning system.

Description:
BACKGROUND OF THE INVENTION 
     An auxiliary air conditioning, heating and engine warming system for trucks is disclosed in my U.S. Pat. No. 4,682,649 dated Jul. 28, 1987, the disclosure of which is incorporated herein by reference. 
     Basically, main and auxiliary vehicle air conditioning systems operate in such a way that when the truck is running, as when the truck is traveling or stopped for a short time period only, the truck air conditioning and heating systems operate in a conventional manner to supply conditioned air or warm air to the truck cab and/or sleeping compartment. At this time, the auxiliary power plant is inactive and has no effect on the operation of the truck air conditioning and heating systems or its electrical system. 
     When the truck stops for a lengthy period and its engine is turned off, the auxiliary air conditioning system is activated to not only supply conditioned air to the truck cab and/or sleeping compartment but also for warming the truck engine and its fuel lines. 
     In the system disclosed in my aforementioned patent, a pair of cut-off valves were provided in the refrigerant pressure lines for isolating the main air conditioning system from the auxiliary air conditioning system or for isolating the auxiliary air conditioning system from the main conditioning system. 
     After considerable research and experimentation, the isolation valve of the present invention has been devised for replacing the pair of cut-off valves disclosed in my aforementioned patent. 
     SUMMARY OF THE INVENTION 
     The isolation valve of the present invention comprises, essentially, a rotary solenoid actuated spindle rotatably mounted in a housing. The spindle has axially spaced lands and grooves wherein the grooves are constructed and arranged to selectively connect the auxiliary air conditioning system to the truck cab while isolating the truck air conditioning system, and for connecting the truck air conditioning system to the truck cab while isolating the auxiliary air conditioning system. By this construction and arrangement, if one system develops a leak, the particular system can be isolated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a schematic drawing of a truck air conditioning system and heating system and an auxiliary power plant for such system including the isolation valve of the present invention. 
         FIG. 2  is a sectional side elevational view of the isolation valve employed in the system, illustrated in  FIG. 1 , showing the valve in a position communicating the auxiliary compressor discharge to the truck sleeper air conditioning units and communicating the discharge from the truck sleeper air conditioning units to the suction side of the auxiliary compressor, while simultaneously closing off the truck compressor discharge and suction ports. 
         FIG. 3  is a sectional side elevational view of the isolation valve shown in  FIG. 2  but shifted to a position where the auxiliary system is shut off and communication is established between the truck sleeper air conditioning units and the truck compressor discharge and suction sides. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, and more particularly  FIG. 1 , a truck engine  12  is equipped with a radiator  13 , behind which is located the usual fan  14  driven by a pulley means  15  on the engine crank shaft. A truck alternator  17  is operated by a drive belt and pulley  18  driven by the pulley means  15 . Similarly, a truck air conditioning compressor  19  is operated by a belt and pulley  20  driven by the pulley means  15 . 
     The truck cab is equipped with a dash-mounted conventional ac/heater unit  21 , and a separate ac/heater unit  22  is provided in the sleeping compartment of the truck tractor. The truck air conditioning condenser  23  may be grill or roof mounted, as found desirable. When grill mounted, an electric temperature controlled fan, not shown, is added to cool the condenser while the vehicle is stationary, or the truck engine fan  14  can be replaced by a full electric fan. 
     An auxiliary power plant  24  includes a suitable supporting and unitizing frame, and may be mounted at any convenient location on the truck tractor, such as behind the cab on the tractor main frame, or in the location of the customary cab step. 
     The auxiliary power plant  24  comprises a small engine  26 , such as a Kubota diesel engine or an equivalent engine. The engine  26  drives a crank shaft pulley  27  connected through a belt  28  with a pulley  29  of the power plant compressor  30 . Another belt  31 , driven by the crank shaft pulley  27 , drives a power plant alternator  32  and also drives a power plant water pump  33 . 
     A power plant heat exchanger  34  includes a chamber  35  receiving hot exhaust gases from an exhaust port  36  of the power plant engine  26 . From the chamber  35 , the spent exhaust gases pass to a muffler  37 , which, for added safety, is preferably connected into the customary vertical exhaust stack of the truck. 
     Within the chamber  35 , the heat exchanger  34  includes heat exchanger coils  38  preferably formed of copper and being of any thermally efficient shape, such as wide, flat, thin coils. 
     A preferably insulated conduit  39  leads from the water jacket of the truck engine  12  to the inlet end of the auxiliary engine  26  water jacket and another insulated conduit  40  leads from the outlet end of the heat exchanger coil  28  back to the water jacket of truck engine  12 . A branch conduit  41  interconnects the power plant water pump  33  with the water return conduit  40 . 
     Air conditioning pressure lines  45  and  46  lead from the truck compressor  19  through the truck cab and sleeper compartment ac units  47  and  48 , each having their own controls, and from these units back to the truck compressor  19 . The return refrigerant line  45  is connected to the isolation valve  43  of the present invention which is also connected with the return refrigerant line  49 . 
     Auxiliary air conditioning pressure lines  49  and  50  lead to and from the power plant compressor  30  through an auxiliary air conditioning condenser  42  and are connected by the isolation valve  43  with the truck air conditioning pressure lines  45  and  46 , respectively. 
     Existing truck heater hoses  54  and  55  extend to and from the truck engine water cooling system and pass serially through the truck cab dash-mounted and sleeper compartment heater units having their own heater controls, as shown. A circulating pump  56  is connected in the heater hose  55 , with a control switch on the power plant panel, not shown, which control panel can be located at any convenient point on the truck. The power plant control panel is wired into the truck electrical system so that the power plant alternator  32  charges the existing truck storage batteries  57 , which are the only batteries employed in the entire system. When the truck engine  12  is not operating, the power plant alternator  32  operates the total electrical system embodied in the invention. 
     A cable  58  interconnects the truck storage batteries with a conventional starter  59  of power plant engine  26 . 
     The details of the construction of the isolation valve  43  of the present invention are illustrated in  FIGS. 2 and 3 . The isolation valve comprises a single housing  43   a  having a plurality of ports  50   a,    46   a ,  46   b  and  45   a ,  49   a , and  45   b  communicating respectively with the auxiliary power plant compressor discharge line  50 , the evaporator inlet line  46 , the truck compressor discharge line  46 , the auxiliary power plant compressor suction line  49 , the evaporator discharge line  45 , and the truck compressor suction line  45 . A spindle  43   b  is rotatably mounted in the housing  43  and is provided with grooves  43   c  and  43   d ,  43   e ,  43   f  and lands  43   e ,  43   f ,  43   g ,  43   h    43   g ,  43   h ,  43   i ,  43   j  constructed and arranged so that when the spindle  43   b  is rotated to the position shown in  FIG. 2 . The auxiliary power plant compressor  30  discharge and suction lines are connected to the evaporators  47  and  48  through the spindle grooves  43   c    43   e  and  43   c , while lands  43   h  and  43   i  close the ports  46   b  and  45   b  communicating with the truck compressor discharge and suction lines  46  and  45 . 
     When the spindle  43   b  has been rotated to the position shown in  FIG. 3 , the truck compressor  19  discharge and suction lines are connected to the evaporators  47  and  48  through the spindle grooves  43   d , while lands  43   i  and  43   g  close the ports  49   a  and  50   a  communicating with the auxiliary power plant discharge and suction lines  50  and  49 . 
     Operation 
     When the truck engine  12  is running, as when the truck is traveling or stopped for a short time period only, the truck air conditioning and heating systems operate in a conventional manner to supply conditioned air or warm air to the truck cab and/or sleeping compartment through the individually controllable units  21  and  22 . At this time, the isolation valve is in the position shown in  FIG. 3  and the auxiliary power plant including its small engine  26  is inactive and has no effect on the operation of the truck air conditioning and heating systemns or its electrical system. 
     When the truck stops for a lengthy period and its engine  12  is shut off, the operation of the truck alternator  17  and compressor  19  of course ceases. At this time, the isolation valve  43  is rotated to the position shown in  FIG. 2  and the auxiliary power plant  24  is activated by starting its relatively small engine  26 , which activates the alternator  32 , water pump  33  and the compressor  30  whenever air conditioning of the truck cab and/or sleeping compartment is demanded. When it is demanded, the connections of the pressurized freon lines  49  and  50  through the isolation valve  43  will supply air conditioning in the same manner that it would ordinarily be supplied by the truck system including the compressor  19 . 
     Simultaneously, the circulating pump  33  constantly draws water from the truck engine water cooling system and pumps it through the coil  38  of the power plant heat exchanger  34  and back to the truck engine, whereby proper heating of the cab and/or sleeping compartment is made available on demand even though the truck engine is not operating. 
     The heat of the exhaust gases from the power plant engine  26  is utilized to heat the water flowing through the heat exchanger coil  38  in a continuous and efficient manner as long as the small engine  26  operates. 
     Additionally, the heated water flowing to and from the water jacket of the truck engine  12  through the insulated conduits  40  and  39  maintains the truck engine warm so that it will start quickly even in very cold weather. The provision of the additional circulating pump  56  in the existing truck heater conduit system renders the operation of the invention even more efficient. 
     While the isolation valve  43  is connected to the electrical system of the truck and is actuated by a switch manually actuated by the truck operator, pressure switches can also be wired into the system so that if, for instance, the auxiliary compressor system should develop a leak, the isolation valve  43  would be automatically rotated to the position shown in  FIG. 3  and would be prevented from rotating to the position shown in  FIG. 2  until the leak has been repaired.