Patent Application
20080014852
With reference to
The HVAC system 10 consists of selected HVAC components and sensors that can be controlled to deliver cooling capacity as required while minimizing the power consumed. For air conditioning, the HVAC system 10 may include a compressor 16, a condenser fan 18, and an evaporator blower 20. The HVAC system 10 may conventionally includes additional components (not shown) such as a condenser, a pressure reduction device, such as an expansion valve, thermostatic expansion valve, orifice tube, and preferably an electronically controlled expansion valve, and an evaporator, all connected in series in a refrigerant flow path with the compressor 20, as is known. The air conditioning system components themselves may be conventional in nature. An exemplary such air conditioning system is shown and described in an application entitled “Energy Efficient Capacity Control System For An Air Conditioning System”, Ser. No. 11/130,576, filed May 17, 2005, the specification of which is hereby incorporated by reference herein. The evaporator blower 20 directs cooled air flow through the passenger compartment 12, as is conventional.
The HVAC system 10 may also includes a heater 22. The heater 22 may be a conventional fuel fired heater or a resistance heater. The heater 22 may be operated at select levels to direct heated air flow through the passenger compartment 12, as is conventional.
The HVAC system 10 may include an operator interface provided by a user input device 24 and a display 26 connected to the controller 14. The controller 14 is also electrically connected to and controls the compressor 16, the condenser fan 18, the evaporator blower 20, and the heater 22.
The HVAC system 10 may include a power system module in the form of a charger/converter 28 connected to a power source 30, such as a conventional vehicle alternator, and/or a vehicle battery and/or to a 110 volt AC power source for use of shore power. The HVAC system 10 in a no-idle, engine off condition is powered by a battery 32 providing DC power, such as 24 volt DC power to power the compressor 16, the condenser fan 18, the evaporator blower 20, and the heater 22. The battery 34 includes a sensor 36 for sensing battery energy. The battery sensor 36 is connected to the controller 14. An ambient sensor block 38 is also connected to the controller 14 for sensing ambient parameters such as passenger compartment temperature, external temperature, or the like.
The HVAC system 10 may be mounted in one or more housings mounted in the passenger compartment 12. The present invention is not directed to the particular form of the HVAC system per se, but rather to the control used in the HVAC system 10, as described below.
The controller 14 may comprise a logic controller of any known form, including a memory 14M, for controlling the various controlled devices. The user input device 24 may include any type of input element such as push buttons, control knobs, touch screen, or the like. The user input device 24 can control both heating and cooling modes and heat and cooling output levels. The display 26 may display various operating parameters including, in accordance with the invention, battery remaining time. The operating parameters may include shore power operation, when battery power is used and a low battery condition.
In an illustrative embodiment of the invention, the heating mode and the cooling mode may provide a plurality of discreet output levels, or may be continuously variable. The presented invention is not directed to any particular heating or cooling mode.
In accordance with the invention, the controller 14 determines estimated battery remaining time based on the manually selected operating parameters from the user input device 24, battery energy and ambient conditions and displays the estimated battery remaining time on the display 26. The controller 14 is connected to the battery sensor 36 to calculate battery capacity. The controller 14 then estimates battery life or battery remaining time based on the heating or cooling level selected and the calculated battery capacity. The memory 14M stores a control program for determining the estimated battery remaining time. The memory 14M also stores parameters relating to power usage characteristics of the HVAC components such as the compressor 16, the condenser fan 18, the evaporator blower 20, and the heater 22. The estimated battery remaining time can be calculated using various different known algorithms. The calculation can be as simple as determining capacity, using a watt-hour rate for the battery, less capacity already consumed, divided by the load power to be consumed depending on the particular user setting. This provides the user the flexibility to select the level of heating or cooling. The controller 14 then determines estimated battery remaining time based on the capacity and the manually selected settings. Feedback is provided to the user in the form of displaying the estimated battery remaining time. The user, knowing the approximate no-idle time, can then determine if a different setting should be selected. Other embedded ambient inputs that could be used to calculate estimated battery remaining time are outside temperature, inside temperature, time of day, month of year and global position. Further inputs that could be included are position of a curtain between a sleeper cab and day cab, desired maximum inside temperature, or other heat sources likely to be used in the passenger compartment, such as microwave, lights and television.
The battery capacity can be calculated using various known techniques. Knowing the amount of energy remaining compared to what is available from a new battery provides the user with an indication of how long the battery will continue to operate before it needs to be recharged. Some of the known methods of determining the state of charge comprise a direct measurement, specific gravity measurements, voltage based estimation or current based estimation. The present invention is not directed to the particular algorithm for determining estimated battery remaining time, but rather to a system and method for providing an indication to a user based on different selected operating parameters of the HVAC system 10.
Referring to
The present invention has been described with respect to flowcharts and block diagrams. It will be understood that each block of the flowchart and block diagrams can be implemented by computer program instructions. These program instructions may be provided to a processor to produce a machine, such that the instructions which execute on the processor create means for implementing the functions specified in the blocks. The computer program instructions may be executed by a processor to cause a series of operational steps to be performed by the processor to produce a computer implemented process such that the instructions which execute on the processor provide steps for implementing the functions specified in the blocks. Accordingly, the illustrations support combinations of means for performing a specified function and combinations of steps for performing the specified functions. It will also be understood that each block and combination of blocks can be implemented by special purpose hardware-based systems which perform the specified functions or steps, or combinations of special purpose hardware and computer instructions.
Thus, there is disclosed a system and method providing an indication of estimated battery remaining time in HVAC systems for a passenger compartment of an over the road vehicle.
