Patent Application
20110056231
The present invention relates to a refrigeration circuit of an automotive air conditioning system which can be used safely even when a certain new-type refrigerant is utilized.
A refrigeration circuit used for an air conditioning system for vehicles has basic configuration as shown in
Instead of the typical refrigerant such as R134a, research and development to find a new-type refrigerant are being performed in order to improve Global Warming Potential (GWP), as disclosed in non-patent document 1. R1234yf has been announced recently as a new refrigerant aiming at such an improvement, and it is becoming possible that it is examined and studied for applying to refrigeration circuits used for an automotive air conditioning system, etc.
Prior art documents
Non-patent documents
Non-patent document 1: Refrigeration, Vol. 83, No. 965, March issue, 2008
Since conventional refrigerant is usually nonflammable, basically combustion preventive measures have not had to be taken against the refrigeration leakage which might be brought when the vehicle is impacted excessively for example. However, molecular structure of the new-type refrigerant R1234yf described above is CF3âCF=CH2 which includes two Hs, and therefore is a little flammable. So it is preferable that a combustion preventive measure is taken in case that a great amount of refrigerant might be leaked.
When the new refrigerant R1234yf is used, if fires derived from R1234yf can be caused they are most likely to break out through the following steps: vehicular crash â>damage or destruction of condenser â>refrigerant leakage â>ignition in the high-temperature engine exhaust manifold. Therefore, this ignition possibility is desired to be reduced.
Accordingly, an object of the present invention is, focusing on such a possibility and demand to prevent from it, to provide a refrigeration circuit of an automotive air conditioning system which can immediately minimize the refrigeration leakage from the circuit caused by an excessive shock, so as to reduce the possibility of fire-breaking when particularly a conventional refrigerant is replaced by the new-type refrigerant R1234yf.
To achieve the above described object, a refrigeration circuit according to the present invention is a refrigeration circuit for a vehicle air-conditioning system comprising a compressor for compressing refrigerant, a condenser for condensing compressed refrigerant, a pressure reduction and expansion means for reducing in pressure and expanding condensed refrigerant, and an evaporator for evaporating pressure-reduced and expanded refrigerant in this order, characterized in that R1234yf is used as refrigerant and a shut-off valve for shutting off the circuit based on an excessive acceleration signal of the vehicle is provided at a position in the circuit each of upstream and downstream of the condenser. That makes it possible that an excessive impact is detected as an excessive acceleration signal, and a shut-off valve is operated based on the excessive acceleration signal, so as to shut instantaneously at upstream and downstream positions of the condenser. As described above, the damage or destruction of the condenser is most suspected as a reason of the refrigerant leakage caused by the excessive impact. Therefore even if the condenser is damaged or destructed, the circuit is instantaneously closed at the positions of upstream and downstream thereto, keeping a minimum leakage of refrigerant, so as to prevent from more leakage, or excessive leakage. As a result, the fire-breaking possibility derived from a leak of the new-type refrigerant R1234yf can be minimized, and a desirable purpose can be achieved.
In the refrigeration circuit for a vehicle air-conditioning system according to the present invention, it is possible either that the excessive acceleration signal is a signal from an acceleration sensor mounted on the vehicle or that the excessive acceleration signal is a signal from a collision sensor provided on an airbag.
Effect according to the Invention
Thus in the refrigeration circuit for a vehicle air-conditioning system, when the refrigerant used is changed to R1234yf, which is a new-type refrigerant, it is possible to instantaneously minimize refrigerant leakage from the circuit in the event applied with an excessive impact, and to reduce the possibility of a fire starting or the like. As a result, it can be promoted to use the new-type refrigerant R1234yf in order to improve the Global Warming Potential (GWP) and so on.
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Hereinafter, a desirable embodiment of the present invention will be explained as referring to figures.
As described above, the basic equipment layout of the refrigeration circuit of a vehicle air-conditioning system as an object of the present invention is shown in
As the excessive acceleration signal, the signal from an acceleration sensor mounted on the vehicle can be used, as well as the signal from a collision sensor provided on an air bag. An example of the control circuitry is shown in
In
As shown in
Consequently, when the new-type refrigerant R1234yf is used, even when impacted excessively the refrigerant leakage from the circuit can be minimized, and the possibility of a fire starting or the like can be kept extremely low. The new-type refrigerant R1234yf is regarded as a superior refrigerant aimed at improvement such as the global warming potential (GWP). The use or examination thereof for the new-type refrigerant R1234yf can be promoted by suppressing the possibility for the fire-outbreak and so on caused by the leak described above.
The refrigeration circuit for a vehicle air-conditioning system according to the present invention is applicable basically for every refrigeration circuit for a vehicle air-conditioning system which uses the new-type refrigerant R1234yf.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-118606 | Apr 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/058289 | 4/27/2009 | WO | 00 | 10/29/2010 |
