Refrigeration – With indicator or tester – Operatively correlated with automatic control
Reexamination Certificate
2001-11-09
2003-10-28
Tanner, Harry B. (Department: 3744)
Refrigeration
With indicator or tester
Operatively correlated with automatic control
C062S129000, C062S193000, C062S228400, C062S323100, C123S1960CP, C340S457400, C368S005000
Reexamination Certificate
active
06637218
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas heat pump-type air conditioner in which a compressor is driven using a gas engine as a drive source, and in particular, a gas heat pump-type air conditioner that can reliably notify the user about the time for changing the engine oil.
2. Description of the Related Art
An air conditioner that carries out cooling and heating by using a heat pump comprises a cooling circuit that includes elements such as an interior heat exchanger, a compressor, an exterior heat exchanger, and an expansion valve. The interior cooling and heating is realized by carrying out the respective exchange of air and heat in an interior heat exchanger and an exterior heat exchanger while the refrigerant is circulating through this circuit. In addition, in this cooling circuit, a refrigerant heater is provided for directly heating the refrigerant itself so as not to depend only on the heat of the refrigerant being absorbed (during operation as a heater) by the exterior heat exchanger.
However, in recent years, instead of the electric motor that is normally used as the drive source of the compressor in the cooling circuit described above, compressors that use gasoline engines as a drive source are being developed. Air conditioners that use this gas engine are generally called gas heat pump-type air conditioners (hereinbelow, abbreviated “GHP”). Like the air conditioner provided with a compressor that uses an electrical motor (hereinbelow, abbreviated “EHP”), with the GHP relatively inexpensive gas is used as the fuel and the running cost does not become expensive, and thus they make possible cost reductions for the users.
In addition, in a GHP, during the heating operation, for example, if the exhaust heat of the high temperature exhaust gas discharged from the gas engine is used as the heat source for the refrigerant, it is possible to obtain a superior heating effect, and at the same time, the efficiency of the energy use can be increased. Incidentally, the heating capacity in a low atmospheric temperature becomes 1.2 to 1.5 times higher than the EHP. In addition, if this type of apparatus is introduced, mechanisms such as the refrigerant heater described above need not be specially provided in the refrigerant circuit.
In addition, in a GHP, the frost removal operation, that is, the defrosting operation, of the interior heat exchanger that is necessary during heating operation can also be implemented by using the waste heat of the engine. Generally, the defrosting operation in the EHP is performed by carrying out frost elimination from the exterior heat exchanger by stopping the heating operation and temporarily carrying out a cooling operation. In this case, the pleasantness of the interior environment deteriorates because cool air is blown into the interior, and this is not desirable in terms of the air conditioning sensation. In a GHP, a continuous heating operation is possible by using the wasted heat due to the circumstances described above, and the problems that cause concern in an EHP do not occur.
However, although GHP has these many advantages, the following problems can be pointed out about the conventional GHP.
As described above, in a GHP engine oil that lubricates the gas engine is used because a gas engine serves as the drive source for the compressor. Since this engine oil will deteriorate while the gas engine is operated, at an appropriate time (that is, before the deterioration begins) maintenance in which an oil change is carried out is necessary. However, the cumulative hours of operation of the gas engine at which the change of the engine oil becomes necessary is rather long, for example, about 10,000 hours, and thus correctly judging the appropriate time for the oil change is difficult.
Against this background, a control method is proposed in Japanese Patent No. 3066123, wherein, when the cumulative hours of operation of the engine reaches a predetermined number of hours, the engine automatically stops, and at the same time, a selection choice is provided that allows extended operation of the engine for a predetermined amount of time even if an oil change is not carried out. Alternatively, when the cumulative hours of operation of the engine has reached a predetermined number of hours, an oil change warning light is displayed, and after the warning signal display for the oil change is displayed, the engine automatically stops at a predetermined operating time if an oil change is not carried out, and at the same time a selection choice is provided that allows extended operation of the engine for a predetermined time.
However, this conventional technology always stops the operation of the engine once at a predetermined amount of cumulative hours of operation of the engine or after the passage of a predetermined extended operation time without an oil change. Thereby, either the oil change is completed before the predetermined amount of the cumulative hours of operation has been reached, or the operation of the compressor that circulates the refrigerant becomes impossible when the oil change is not completed quickly after the oil change warning signal is displayed, and thus there are cases wherein the forcible stopping of the air conditioning operation becomes unavoidable when the time for the oil change has arrived.
This type of forcible stopping of the air conditioning operation is undesirable in terms of the capacity of a gas heat pump-type air conditioner to maintain a pleasant interior environment by the cooling operation and the heating operation, for example. Therefore, the development of a heat pump air conditioner that does not forcibly stop the operation of the air conditioner, and furthermore can reliably notify the user about the arrival of the time for an oil change for the gas engine is desirable.
In consideration of the problems described above, it is an object of the present invention to provide a gas heat pump-type air conditioner that can reliably notify the user about the arrival of the time for changing the engine oil of the gas engine that drives the compressor without stopping the operation of the gas engine.
SUMMARY OF THE INVENTION
The present invention uses the following device to resolve the problems described above.
In a first aspect of a gas heat pump-type air conditioner that forms a cooling cycle by circulating refrigerant using a compressor having a gas engine as a power source, the user is notified about the time for changing the engine oil by displaying a warning while continuing to operate the gas engine when the cumulative hours of operation (t) of the gas engine has reached a predetermined time (T
2
), and at the same time displaying a warning and carrying out a warning restoration operation procedure after carrying out the first stop procedure subsequent to reaching the predetermined time (T
2
).
According to this type of a gas heat pump-type air conditioner, while the operation of the gas engine continues, at the point in time that the cumulative hours of operation (t) reaches a predetermined time (T
2
), the user is notified that the time for changing the engine oil has arrived by a warning message, and at the same time, after the initial operation stop subsequent to reaching the predetermined time (T
2
), by carrying out a warning restoration operation procedure that is different from the normal procedure, the user becomes strongly aware of the time for changing the engine oil.
In a second aspect of the gas heat pump-type air conditioner that forms a cooling cycle by circulating refrigerant with a compressor having a gas engine as a power source, the user is notified about the time for changing the engine oil by forcibly reducing the engine revolutions for the gas engine to the minimum number of revolutions when the cumulative hours of operation (t) of the gas engine has reached a predetermined time (T
3
).
According to this type of a gas heat pump-type air conditioner, when the cumulative hours of operation has reached a predetermined time (T
3
), the gas e
Mitsubishi Heavy Industries Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tanner Harry B.
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