JP2007168775A - Energy efficient capacity control for air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning system for optimizing a capacity (or capability) of the air conditioning system with respect to cooling requirements of a sleeper compartment of a truck so as to minimize energy consumption and its operating method. <P>SOLUTION: The air conditioning system 10 is provided for cooling the sleeper compartment 16 of the truck when the main engine of the truck is not operating. The air conditioning system includes a variable speed compressor 20, a variable speed condenser fan 22, a variable speed evaporator blower 24, and a controller 14 configured to optimize a cooling capacity of the system with respect to the cooling requirements of the sleeper compartment by selectively adjusting the speeds of the variable speed components 20, 22, 24. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioning system for automobiles, and more particularly to an air conditioning system for a large truck bed cab or bed section.

Currently, air conditioning systems for automobiles, particularly those for large truck bed cabs, are provided through an air conditioning system driven by an engine. However, interest in both atmospheric and noise pollution has in some cases created a situation that does not allow a truck to idle its engine to operate its sleeper cabin air conditioning. In addition to pollution concerns, the cost of overnight idling fuel is estimated at $ 2,400 annually and the maintenance cost is estimated at $ 250. To air pollution, it has been estimated that one year of idling single track of 113 kg CO, 279 kilograms of NO _X, and 17 tons of CO ₂ is discharged.

  Possible alternatives to idling the main engine include the following: Diesel engine rotates self-propelled AC compressor and alternator DC / AC, existing cab air conditioning, and existing automobile Auxiliary power devices that function in conjunction with heating, ventilation, and cooling (HAVC) systems; power generation equipment (GENSET) that drives the generator that supplies the AC electricity used by the diesel engine; the truck service area A 120V AC electric terrestrial power supply; and an auxiliary battery mounted in the vehicle with an additional battery used by the sleeper cab HVAC system.

  Electrically driven airtight vapor compression air conditioning (A / C) systems are common, but are rarely used in automobiles. A major reason why this reliable air-conditioning supply means is not used is the lack of available power. U.S. Pat. No. 6,057,096 discloses a vapor compression A / C system that attempts to improve efficiency by controlling a variable displacement compressor.

US Pat. No. 6,622,500

  Accordingly, it is an object of the present invention to provide a method of operating an air conditioning system that optimizes the capacity (or capacity) of the air conditioning system to the cooling requirements of the couch section and minimizes energy consumption. Another object of the present invention is to provide an air conditioning system capable of optimizing the capacity (or capacity) of the air conditioning system with respect to the cooling requirements of the bed section and minimizing energy consumption. .

According to one aspect of the present invention, there is provided a method for operating a vapor compression air conditioning system for a truck couch section, said air conditioning system comprising a variable speed compressor for refrigerant pressurization, an evaporator, and A variable speed blower for directing the air flow through the evaporator.
The method of the present invention is:
a) monitoring the temperature of the air in the sleeper compartment;
b) monitoring the temperature of the air stream from the evaporator;
c) monitoring the refrigerant discharge pressure of the compressor;
d) monitoring coolant overheating (condition);
e) adjusting the speed of the compressor based on the monitoring of steps a, b and c; and
f) adjusting the blower speed based on the monitoring of step d.

  As one feature of the present invention, step e includes adjusting the voltage to the variable speed compressor. As one feature of the present invention, step f includes adjusting the voltage to the variable speed blower. According to one characteristic of the invention, step e comprises comparing the temperature of the air from the evaporator with the dew point.

  As one feature of the present invention, step e includes comparing the temperature of the couch section with a set temperature. As another feature of the present invention, step e further includes comparing the temperature of the air from the evaporator with a set temperature. As another feature of the invention, step e further comprises comparing the temperature of the air from the evaporator with the dew point.

As one feature of the present invention, step f includes comparing the coolant overheating (state) with a reference value. According to one characteristic of the invention, step e comprises comparing the discharge pressure with a reference value.
As one feature of the present invention, the method further includes:
g) monitoring coolant overcooling (condition); and
h) adjusting the speed of the condenser fan based on the monitoring of step g.

  In accordance with one aspect of the present invention, an air conditioning system is provided for use to cool a truck couch section. The system of the present invention includes: a coolant channel; a variable speed compressor for pressurizing the coolant in the coolant channel; a condenser disposed downstream of the compressor in the coolant channel; a condensation of the coolant channel An evaporator located downstream from the oven; a variable speed blower configured to direct the air flow through the evaporator to cool the bed compartment; the temperature of the air in the bed compartment, the temperature of the air flow from the evaporator A refrigerant discharge pressure of the compressor; and a plurality of sensors for monitoring coolant overheating (condition) in the coolant flow path; and a controller connected to the sensors, the compressor, and the blower, the plurality of sensors A controller configured to selectively adjust the speed of the compressor and blower based on the signal received from the sensor.

  As one feature of the present invention, the controller is configured to adjust the speed of the compressor based on a signal indicative of the temperature of the air in the couch section. As one aspect of the present invention, the controller is configured to adjust the speed of the compressor based on a signal indicative of the temperature of the air stream exiting the evaporator.

  According to one aspect of the invention, the controller is configured to adjust the speed of the compressor based on a signal indicative of the compressor discharge pressure. In accordance with one aspect of the present invention, the controller is configured to adjust the speed of the compressor based on signals indicative of the temperature of the bunk compartment air, the temperature of the air flow exiting the evaporator, and the discharge pressure of the compressor. .

  As one feature of the present invention, the controller is configured to adjust the speed of the blower based on a signal indicative of coolant overheating (state). In one aspect of the invention, the system further includes a variable speed condenser fan configured to direct the air flow through the condenser, and the controller is based on a signal indicative of coolant subcooling (condition). It is configured to adjust the speed.

According to one aspect of the present invention, a method is provided for operating a vapor compression air conditioning system for a truck couch section, the air conditioning system comprising a variable speed compressor for refrigerant pressurization, an evaporator, and A variable speed blower for directing the air flow through the evaporator.
The method of the invention is:
a) adjusting the speed of the compressor based on the temperature of the air stream from the evaporator and the discharge pressure of the coolant from the compressor; and
b) including adjusting the blower speed based on the coolant overheating (state).

  As one feature of the present invention, step a further includes adjusting the speed of the compressor based on the temperature of the air in the couch section. As one aspect of the present invention, the method further includes adjusting the speed of the variable speed condenser based on the coolant subcooling (state).

  In accordance with one aspect of the present invention, an air conditioning system is provided for use to cool a truck couch section. The system of the present invention includes: a coolant channel; a variable speed compressor for pressurizing the coolant in the coolant channel; a condenser disposed downstream of the compressor in the coolant channel; a condensation of the coolant channel An evaporator located downstream of the oven; a variable speed blower configured to direct the air flow through the evaporator to cool the bed section; the temperature of the air flow from the evaporator, the coolant from the compressor A controller is provided that is configured to selectively adjust the speed of the compressor and blower based on the discharge pressure and a signal indicative of coolant overheating (state).

  In one aspect of the invention, the system further includes a variable speed condenser fan configured to direct the air flow through the condenser, and the controller is based on a signal indicative of coolant subcooling (condition). It is configured to adjust the speed.

  Other objects, features and advantages of the present invention will become apparent from the following detailed description, claims and drawings.

  As shown in FIGS. 1 and 2, the present invention provides an electrically driven hermetic vapor compression air conditioning A / C system 10. The hermetic vapor compression air-conditioning A / C system 10 of the present invention utilizes an electronic control mechanism or controller 14 that effectively matches the cooling output to the cooling requirements, thereby enabling comfort within the vehicle 12 without operating the main engine. Will maintain the correct temperature.

  Wind tunnel tests and some additional computer calculations were performed on the sleeper cab 16 to determine the cooling requirements for a typical Class H sleeper cab 16. The result is shown in FIG. As preferred, the system 10 according to the present invention attempts to accurately match or match the cooling output to the cooling requirements in order to operate the A / C system 10 in the most efficient manner.

  The system 10 includes selected air conditioning components and sensors that can be controlled to provide the required cooling capacity (or cooling capacity) while minimizing power consumption. As preferred, the system 10 includes a compressor 20, a compressor controller 21, a condenser fan 22, and an evaporator blower 24, all of which operate at continuously variable speeds. The system 10 further includes a pressure reducing device 28 such as a condenser 26, expansion valve, temperature self-regulating expansion valve, orifice tube, and preferably electronically controlled expansion valve, and an evaporator 30, which are preferred. Are all connected in series with the compressor 20 in the coolant flow path 32. FIG. 1 shows a plurality of sensors used to determine the control operation, which are sensors 34 and 36 for monitoring the compressor discharge temperature T1 and the compressor discharge pressure P1, the compressor intake temperature. Sensors 38 and 40 for monitoring T2 and compressor suction pressure P2, sensor 42 for monitoring expansion valve inlet temperature T3, sensor 44 for monitoring expansion valve outlet temperature T4, and evaporator air outlet temperature T5 It includes a sensor 46 for monitoring and, preferably, a sensor 47 for monitoring a vehicle interior temperature T6, which is the interior temperature of the vehicle couch section.

  Also shown in FIG. 1 are sensors 48 and 49 for monitoring the ambient dry bulb thermometer and ambient relative humidity. Also shown in FIG. 1 is an operator control 50, which is connected to the controller 14 in the same manner as the sensors described above. The controller 14 preferably includes a printed circuit board having a control algorithm described below. Preferably, as shown in FIG. 2, the system 10 is powered by the battery pack 52 when in the non-idling mode, and when in the idling mode, the vehicle alternator 54, the battery 56, and the charger / Powered by converter 58. Preferably, charger / converter 58 converts 120 volts AC to 24 volts DC for charging the unit and auxiliary battery.

  As shown in FIG. 2, system controller 14 prefers to operate at 12 volts DC, whereas variable speed compressor 20, condenser fan 22, and evaporator blower 24 operate at 24 volts DC. To do. Further, although not shown, an electronically controlled expansion valve 28 may be connected to the electronic control mechanism in a manner similar to the compressor 20, condenser fan 22, and evaporator blower 24.

  FIG. 4 shows a system algorithm diagram used by the electronic controller. Here, the various verification parameter values shown are the currently best predicted values for a particular system, and these values can be varied to optimize the system and control mechanism for other specific applications. It must be understood that it may be. Therefore, a value for adjustment to the set temperature with respect to the bed temperature and the evaporator output temperature, a value for adjustment to the dew point for the evaporator output temperature vs. dew point comparison, a reference pressure value for the compressor discharge pressure (P1), supercooling That the match value for (SC) and the match value for superheat (SH) may all be adjusted to optimize a particular system depending on the particular components and parameters associated with the particular system. Must be understood.

  As shown in FIG. 4, the controller 14 controls the temperature of the air in the bed section 16, the temperature of the air flow output from the evaporator 30, the discharge pressure P1 of the compressor 20, the supercooling (state) of the coolant, In addition, the speed of the compressor 20, the fan 22, and the blower 24 is changed depending on the overheating (state) of the coolant. More specifically, the controller is preferred as the temperature of the bed when compared to the set temperature, the temperature of the air flow from the evaporator 30 when compared to the set temperature, and the evaporator 30 when compared to the dew point. The speed of the compressor 20 is adjusted through an increase or decrease in voltage to the compressor 20 based on the temperature of the air flow from the outlet, the discharge pressure P1 from the compressor 20 when compared to the reference pressure. The controller 14 also adjusts the speed of the blower 24 through an increase or decrease in the voltage to the blower 24 based on the overheating of the coolant when compared to the reference value, and the amount of coolant when compared to the reference value. Based on the overcooling, the speed of the fan 22 is adjusted through an increase or decrease in voltage to the fan 22.

  Here, it should be understood that control of certain system components is more important (rather than control than other system components) for the purpose of minimizing power consumption. For example, compressor voltage control will have the most important impact on power consumption, blower voltage control will be the next most important, and fan voltage control will be the next most important . In this regard, in some systems it may be desirable not to control non-priority components such as, for example, control of fan voltage. In such a case, the algorithm may simply be modified by eliminating supercooling (SC) verification and associated instructions to increase or decrease the fan voltage.

  A system constructed and controlled according to the present invention was installed in a test bench vehicle and its characteristics were tested in a wind tunnel. As shown in FIG. 5, the test car is a class 8 heavy truck with no insulation in the walls, a 2.0 meter cab width, a 2.4 meter bed width, It had a windscreen area of 0.63 square meters, a window of 0.31 square meters, and a bed body of 1.8 meters long x 2.0 meters wide x 3.0 meters high. The test unit included a continuously variable compressor 20, a condenser fan 22, and an evaporator blower 24. Further, a manually controlled expansion valve 28 was used instead of the electronically controlled expansion valve. The test system 10 was constructed as a module 61 cm wide x 61 cm high x 41 cm deep and installed under the bed bed. The weight of the system components is shown in FIG.

  FIG. 3 shows the vehicle cooling load requirements generated, at least in part, by a test vehicle wind tunnel test, and the results for overnight cooling after the end of engine idling are shown in FIG. The peak cooling demand is the result of engine heat (represented by the temperature of the engine oil and the temperature at the top of the radiator tank) that heats the interior of the cab and bed during the early periods of non-idling. The results of this test were incorporated into a computer model simulation, which produced an accurate comparison between the simulation results and the test results.

  Preliminary tests showed that the required cooling capacity (or cooling capacity) was achieved with minimal electrical input. This test demonstrates the ability to maintain the couch section at 21 ° C / 70 ° F for approximately 8 hours with an ambient ambient temperature of 32 ° C / 90 ° F and 2500 watts (electrical) over an 8 hour period. ) Was required. The first generation unit in the middle setting used a 12 volt DC 100 amp hour battery and generated 6 hours of power (2000 watts of electricity). The second generation unit in the intermediate setting used a 12 volt DC 125 amp hour battery and generated approximately 8 hours of operation.

  With an additional voltage and a refined (or precise) control mechanism and coolant component, an extended lifetime could be achieved. FIG. 8 is a graph showing test results for overnight operation of a non-idling HVAC module at an ambient temperature of 30 ° C. (90 ° F.) and a relative humidity of 40%.

  Figures 9 and 10 show the results of initial tests made to determine the most effective operating point for this system. Further, FIG. 11 shows the influence of the compression ratio of the compressor on the capacity, and FIG. 12 is a table relating the pressure ratio and amperage, overheating, the suction pressure of the compressor 20, and the discharge pressure of the compressor 20. Provides an indication of how to control the system 10 to achieve better battery life.

  The results of the above and other tests show that with the myriad variable compressor 20 and myriad variable fan 22 and blower motor 24, the system 10 can operate more effectively than with the current manufacturing components. ing.

  Advantages of the present invention include appropriate selection of controllable components and control that effectively matches the output of the system to the requirements to minimize power consumption.

1 is a block diagram of an air conditioning system embodying the present invention for use to cool a truck sleeper cab or bed compartment. FIG. FIG. 2 is a schematic diagram of electrical control for the system of FIG. 1. 2 is a graph illustrating the specific idle cooling requirement of a truck bed section that can use the system of FIG. 2 is a control algorithm (first half) for the system of FIG. 2 is a control algorithm (second half) for the system of FIG. FIG. 2 is a side view of a truck that can use the system of FIG. 1. FIG. 6 is a graph showing a particular temperature associated with the track of FIG. 5 during a particular non-idling condition. 2 is a table showing the weight of a test system constructed in accordance with the present invention. It is a graph which shows the test result of the test system which embodies this invention. Figure 5 is a graph of input wattage and cooling wattage vs. ambient temperature of a condenser for a system embodying the present invention. Figure 5 is a graph of input wattage and cooling wattage vs. ambient temperature of a condenser for a system embodying the present invention. 4 is a graph of cooling capacity vs. compression ratio for a system embodying the present invention. Figure 3 is a table comparing certain system parameters of a system embodying the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Air-conditioning system of this invention 12 Automobile 14 System controller 16 Sleeper section 20 Variable speed compressor 21 Compressor controller 22 Variable speed condenser fan 24 Variable speed evaporator fan 26 Condenser 28 Expansion valve 30 Evaporator 32 Coolant flow path 34-49 Sensor 50 Operator control unit 52 Battery pack 54 Automotive AC generator 56 Battery 58 Charger / converter P1 Compressor discharge pressure P2 Compressor intake pressure T1 Compressor discharge temperature T2 Compressor intake temperature T3 Expansion valve inlet temperature T4 Expansion valve outlet temperature T5 Evaporator Air outlet temperature T6 Car interior temperature

Claims (22)

A method for operating a vapor compression air conditioning system for a truck bed section, wherein the air conditioning system directs a variable speed compressor for refrigerant pressurization, an evaporator, and an air flow through the evaporator Includes variable speed blower for attaching:
a) monitoring the temperature of the air in the sleeper compartment;
b) monitoring the temperature of the air stream from the evaporator;
c) monitoring the refrigerant discharge pressure of the compressor;
d) monitoring coolant overheating;
e) adjusting the speed of the compressor based on the monitoring of steps a, b and c; and
f) A method comprising the step of adjusting the speed of the blower based on the monitoring of step d.   The method of claim 1, wherein step e comprises adjusting the voltage to the variable speed compressor.   The method of claim 1, wherein step f includes adjusting the voltage to the variable speed blower.   The method of claim 1, wherein step e comprises comparing the temperature of the air from the evaporator with a dew point.   The method of claim 1, wherein step e includes comparing the temperature of the couch section to a set temperature.   The method of claim 5, wherein step e comprises comparing the temperature of air from the evaporator to a set temperature.   The method of claim 6, wherein step e further comprises comparing the temperature of the air from the evaporator with a dew point.   The method of claim 1, wherein step f comprises comparing the coolant subcooling with a reference value.   The method of claim 1, wherein step e includes comparing the exhaust pressure with a reference value. g) monitoring coolant subcooling; and
The method of claim 1, further comprising: h) adjusting the speed of the condenser fan based on the monitoring of step g. An air conditioning system for use in cooling a truck sleeper compartment:
Coolant flow path;
A variable speed compressor for pressurizing the coolant in the coolant flow path;
A condenser disposed downstream of the compressor in the coolant channel;
An evaporator disposed downstream of the condenser in the coolant channel;
A variable speed blower configured to direct an air flow through the evaporator to cool the bed section;
A temperature of the bed compartment air, a temperature of the air flow from the evaporator, a coolant discharge pressure of the compressor; and a plurality of sensors for monitoring coolant overheating in the coolant flow path; and
A controller connected to the sensor, the compressor, and the blower, the controller configured to selectively adjust the speed of the compressor and the blower based on signals received from the plurality of sensors; A system with.   The system of claim 11, wherein the controller is configured to adjust the speed of the compressor based on a signal indicative of the temperature of the bed compartment air.   The system of claim 11, wherein the controller is configured to adjust the speed of the compressor based on a signal indicative of a temperature of an air stream exiting the evaporator.   The system of claim 11, wherein the controller is configured to adjust the speed of the compressor based on a signal indicative of the discharge pressure of the compressor.   12. The controller is configured to adjust the speed of the compressor based on signals indicative of the temperature of the bed compartment air, the temperature of the air flow exiting the evaporator, and the discharge pressure of the compressor. The system described in.   The system of claim 11, wherein the controller is configured to adjust the speed of the blower based on a signal indicative of coolant overheating.   The apparatus further comprises a variable speed condenser fan configured to direct an air flow through the condenser, wherein the controller is configured to adjust the speed of the fan based on a signal indicating coolant subcooling. The system according to claim 11. A method for operating a vapor compression air conditioning system for a truck bed section, wherein the air conditioning system directs a variable speed compressor for refrigerant pressurization, an evaporator, and an air flow through the evaporator With variable speed blower for attaching:
a) adjusting the speed of the compressor based on the temperature of the air stream from the evaporator and the discharge pressure of the coolant from the compressor; and
b) A method comprising adjusting the speed of the blower based on coolant overheating.   The method of claim 18, wherein step f further comprises adjusting the speed of the compressor based on the temperature of the air in the bed section.   The method of claim 18, further comprising adjusting a speed of the variable speed condenser based on coolant subcooling. An air conditioning system for use in cooling a truck sleeper compartment:
Coolant flow path;
A variable speed compressor for pressurizing the coolant in the coolant flow path;
A condenser disposed downstream of the compressor in the coolant channel;
An evaporator disposed downstream of the condenser in the coolant channel;
A variable speed blower configured to direct an air flow through the evaporator to cool the bed section; and
The speed of the compressor and the blower is selectively adjusted based on the temperature of the air flow from the evaporator, the discharge pressure of the coolant from the compressor, and a signal indicating the overheating of the coolant. A system with a controller.   Further comprising a variable speed fan configured to direct an air flow through the condenser, the controller being configured to adjust the speed of the fan based on a signal indicative of coolant subcooling. Item 22. The system according to Item 21.

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