JP2004352057A - Air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner for a vehicle which simply carrying out flow rate control of an engine coolant corresponding to durability of a heater core 10 and a flow rate and a pressure of the engine coolant flowing to the heater core 10. <P>SOLUTION: The air conditioner 100 for the vehicle is provided with the heater core 10; an inlet pipe 1; an outlet pipe 2; a by-pass pipe 3; and a shut-off valve 4. The air conditioner is provided with a flow rate detection sensor 5 for detecting the flow rate of the engine coolant circulating through the inlet pipe 1; and a control part 6 for carrying out the opening/closing control of the shut-off valve in response to the flow rate detected by the flow rate detection sensor 5. Thereby, the control of the flow rate corresponding to the durability of the heater core 10 and the flow rate and the pressure of the engine coolant flowing to the heater core 10 is simply carried out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle air conditioner mounted on a vehicle.
[0002]
[Prior art]
Conventionally, in order to protect the heater core from the engine coolant flowing at a high flow rate and a high pressure, the flow rate and the pressure of the engine coolant flowing at a high flow rate and a high pressure before the engine coolant flows into the heater core. There is a vehicular air conditioner provided with a throttle resistor for reducing the pressure.
[0003]
[Problems to be solved by the invention]
However, since this throttle resistance always lowers the flow rate and pressure of the engine coolant flowing toward the heater core, even if the engine coolant is in the low flow rate and low pressure use region, only the predetermined flow rate and pressure are used. Lower it.
[0004]
Thus, the engine coolant having a low flow rate and a low pressure before reaching the heater core flows through the heater core in a state where the flow rate and the pressure are further reduced through the throttle resistance.
[0005]
Even if the engine coolant, which is hot water, flows through the heater core at a low flow rate and a low pressure, the heating capability of the heater core, that is, the capability of warming the cold air in the passenger compartment and generating hot air may be weakened.
[0006]
Further, since the throttle resistance is a fixed throttle, it has been troublesome to select a throttle resistance having an inner diameter suitable for the characteristics of the pump in the engine coolant circuit.
[0007]
Further, with the progress of the processing technology of the heater core, the heater core has been further reduced in size, weight, and thickness, so that there is no problem even if the engine coolant flows through the heater core at the maximum flow rate. The durability of the heater core must also be ensured.
[0008]
The present invention has been made in view of the above points. That is, it is an object of the present invention to provide a vehicle air conditioner capable of securing heating performance in the entire flow rate range of the engine coolant without significantly improving the durability of the heater core.
[0009]
[Means for Solving the Problems]
2. The vehicle air conditioner according to claim 1, wherein the heater core communicates with the heater core, an inflow pipe through which an engine coolant flowing into the heater core flows, and the engine cooling flowing through the heater core through the heater core. 3. An outlet pipe through which liquid flows, a bypass pipe connecting the inflow pipe and the outflow pipe, and a bypass pipe bypassing the engine coolant flowing through the inflow pipe to the outflow pipe, and a bypass pipe provided in the middle of the bypass pipe. Opening / closing valve, detecting means for detecting a flow rate of the engine coolant flowing through the inflow pipe, and control means for controlling opening / closing of the opening / closing valve according to the flow rate of the engine coolant detected by the flow rate detecting means. It is characterized by having.
[0010]
According to the present invention, the amount of the engine coolant flowing into the heater core can be adjusted according to the flow rate of the engine coolant. Heating performance can be secured in the area. In addition, by adjusting the amount of the engine coolant to the heater core in the high flow rate region, the pressure information can be suppressed, and the durability of the heater core itself does not need to be significantly improved.
[0011]
3. The vehicle air conditioner according to claim 2, wherein the control unit includes a comparison unit that compares a flow rate of the engine coolant detected by the detection unit with a predetermined flow rate. When it is determined that the flow rate of the liquid is larger, control for opening the on-off valve is performed.
[0012]
According to the present invention, when the engine coolant flowing toward the heater core has a predetermined flow rate or more, the on-off valve arranged in the bypass pipe is opened, and the engine coolant can flow not only into the heater core but also into the bypass pipe. Therefore, the flow rate of the engine coolant flowing into the heater core can be reduced, and the flow rate of the engine coolant can be controlled in accordance with the durability of the heater core.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
A vehicle air conditioner 100 according to one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram schematically showing the configuration of a vehicle air conditioner 100 of the present invention.
[0014]
In FIG. 1, reference numeral 1 denotes an inflow pipe of the vehicle air conditioner 100. This inflow pipe 1
This pipe connects a water jacket of an engine (not shown) and a heater core 10 described later. The engine coolant, which has exchanged heat with the engine in the water jacket and has become hot water, flows through a radiator (not shown) and this pipe (inflow pipe 1), and flows into the heater core 10.
[0015]
The heater core 10 is a heat exchange unit that heats the interior of the vehicle by exchanging heat between the engine coolant that has become hot water and the air that is blown into the vehicle interior, and turning the air that is blown into the vehicle interior into warm air.
[0016]
FIG. 2 shows a structural diagram of a typical heater core 10. The heater core 10 communicates with the inlet pipe 11 communicating with the flow pipe 1, the inlet tank 12a in which the engine coolant flowing from the inlet pipe 11 is temporarily stored, and the inlet tank 12a, and is stored in the inlet tank 12a. A tube 13 for gradually flowing the engine coolant, and an outlet tank 12b for temporarily storing the engine coolant for flowing the engine coolant for heat exchange while flowing through the tube 13 to the outlet pipe 3. And an outlet pipe 14 through which the engine coolant stored in the outlet tank 12b flows out to the outlet pipe 2.
[0017]
Fins 15 are formed on the outer shell of the tube 13, and heat of the engine coolant, which is hot water flowing through the tube 13, is released from the fins 15 to the outside air via the tube 13.
[0018]
The outside air that has released heat from the fins 15 becomes hot air and blows out into the vehicle interior, thereby heating the vehicle interior.
[0019]
The shape of the fins 15 of the heater core 10, the respective joint structures of the inlet tank 12a, the outlet tank 12b and the tube 13, the respective joint structures of the inlet pipe 11, the outlet pipe 14 and the tank 12, and the like are not shown in the figure. There are many similarities.
[0020]
However, the flow rate of the engine coolant to be circulated to the heater core 10 is 5 to 20 l / min, which is lower than that of the radiator, which is 20 to 80 l / min.
[0021]
Therefore, in order to increase the heat exchange rate at a low flow rate, various measures different from the radiator have been made.
[0022]
The method of improving the heat exchange rate at a low flow rate may differ depending on the type of the heater core 10.
[0023]
The types of the heater cores 10 are roughly classified into two types: a plate fin type and a corrugated fin type.
[0024]
In the case of the plate fin type heater core 10, a turbulator (inner fin) (not shown) may be inserted into the tube 13 to cause a turbulent flow of the engine coolant to improve the heat exchange rate.
[0025]
Similarly, in the case of the corrugated fin type heater core 10, the tube 13 may be formed flat so that heat can be easily radiated from the engine coolant flowing through the tube 13.
[0026]
Furthermore, regardless of the above-mentioned two types, what can generally be said about the heater core 10 is that by inserting dimples or ribs (not shown) in the tube 13, the engine coolant flowing through the tube 13 flows through the tube 13. In some cases, turbulence is created.
[0027]
As another method, there is a case where the thickness of the tube 13 is reduced to the limit.
[0028]
Therefore, when the engine coolant having a high flow rate and a high pressure suddenly flows in, the tube 13 may be damaged at a portion formed to be thin.
[0029]
The outflow pipe 3 is a pipe for returning the engine coolant having undergone the heat exchange in the heater core 10 to a coolant circuit (not shown). The engine coolant, which is connected to the above-described outlet tank 12b and has been subjected to heat exchange in the tube 13 and stored in the outlet tank 12b, flows out of the heater core 10.
[0030]
The bypass pipe 3 is a bypass which connects the above-described inflow pipe 1 and outflow pipe 3. An on-off valve 4 described later is provided on the way.
[0031]
The on-off valve 4 is an electromagnetic valve that receives an electric signal from a control unit 6 described later and opens or closes a valve (not shown) according to the signal. When the valve of the on-off valve 4 is closed, the engine coolant cannot flow through the bypass pipe 3 described above.
[0032]
The flow rate detection sensor 5 detects a flow rate of the engine coolant flowing into the heater core 10. The flow rate detecting sensor 5 corresponds to a flow rate detecting means described in the claims.
[0033]
The flow rate detection sensor 5 is disposed in the middle of the above-described inflow pipe 1 and upstream of a branch portion between the above-described bypass pipe 4 and the inflow pipe 1, and is used for cooling the engine flowing through the inflow pipe 1. The flow rate of the liquid is constantly detected, converted into an electric signal, and transmitted to a control unit 6 described later.
[0034]
There are various methods for detecting the flow rate of the fluid, such as an electromagnetic type, a Coriolis type, and a turbine type. In the case of the flow rate detection sensor 5, it is preferable to use a differential pressure type flow rate detection means.
[0035]
The reason for this is that when the flow rate detection sensor 5 is disposed in the inflow pipe 1, a large-scale work is not required, and the flow rate sensor has a low failure rate because it is inexpensive and has few moving parts.
[0036]
The control unit 6 receives the flow rate value detected by the flow rate detection sensor 5 described above, performs a comparison calculation with a predetermined flow rate value, and, in accordance with a result of the comparison calculation, sets the valve to the on-off valve 4 described above. A control signal is output to open or close.
[0037]
The control unit 6 is a microcomputer including a well-known CPU, RAM, ROM, and the like, and corresponds to control means described in claims.
[0038]
FIG. 3 is a flowchart showing the operation of the vehicle air conditioner 100 having the above-described configuration, which controls the flow of the engine coolant into the heater core 10.
[0039]
In step S1, the flow rate sensor 5 detects the flow rate of the engine coolant flowing through the inflow pipe 1, and inputs the detected flow rate value to the control unit 6. Then, the process proceeds to step S2.
[0040]
In step S2, the flow rate value detected in step S1 is output to the control unit 6, and the control unit 6 compares the input detected flow rate value with a predetermined flow value. Then, the process proceeds to step S3. The content of the processing in step S2 corresponds to the comparing means described in the claims.
[0041]
In step S3, when the flow rate value detected by the flow rate detection sensor 5 in step S1 is larger than the predetermined flow rate value, the process proceeds to step S4, and the control unit 6 performs control to open the on-off valve 4.
[0042]
If the detected flow rate value is smaller than the predetermined flow rate value, the process proceeds to step S5, where the on-off valve 4 is controlled to be closed when it is open, and the present flow ends.
[0043]
In the flowchart shown in FIG. 3, when the detected flow rate value exceeds the predetermined flow rate value by one time in the comparison operation in step S <b> 2, the opening / closing valve 4 is controlled to be opened. For example, the on-off valve 4 may be opened when the detected flow rate value exceeds a predetermined flow rate value, for example, about 2 to 10 times per second.
[0044]
Alternatively, an average value of the detected flow rate values may be obtained in step S1, and this average value may be compared with a predetermined flow rate value in step S2.
[0045]
The above-mentioned “predetermined flow rate value” is a theoretical value of a flow rate value which is stored in the ROM on the ECU constituting the control unit 6 and is about 5 to 10% lower than the maximum flow rate value that the heater core 10 can withstand. Value. This theoretical value is assumed to be obtained in advance by a predetermined calculation.
[0046]
With the above-described configuration and operation, the vehicle air conditioner can easily perform the durability of the heater core 10 and the flow rate of the engine coolant according to the flow rate and the pressure of the engine coolant flowing into the heater core 10. 100 can be provided.
[0047]
(Modification)
In the embodiment described above, the flow rate detection sensor 5 is used as the detection means described in the claims, but a pressure sensor that detects the pressure of the engine coolant in the inflow pipe 1 or the heater core 10 may be used.
[0048]
In this case, the predetermined value stored in the ROM (not shown) of the control unit 6 and compared with the pressure value detected by the pressure sensor is also a pressure value that is about 5 to 10% lower than the maximum pressure value that the heater core 10 can withstand. Is the theoretical value of
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically illustrating a configuration of a vehicle air conditioner 100 according to an embodiment of the present invention.
FIG. 2 is an explanatory view schematically showing a typical heater core 10;
FIG. 3 is a flowchart showing a flow relating to control of a flow rate of an engine coolant of the vehicle air conditioner 100.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inflow pipe 2 Outflow pipe 3 Bypass pipe 4 On-off valve 5 Flow rate detection sensor (detection means)
6 control part (control means)
DESCRIPTION OF SYMBOLS 10 Heater core 11 Inlet pipe 12a Inlet tank 12b Outlet tank 13 Tube 14 Outlet pipe 15 Fin 100 Vehicle air conditioner

Claims (2)

A heater core,
An inflow pipe that communicates with the heater core and through which the engine coolant flowing into the heater core flows;
An outlet pipe in communication with the heater core, through which the engine coolant flowing out of the heater core flows;
A bypass pipe connecting the inflow pipe and the outflow pipe, and bypassing the engine coolant flowing through the inflow pipe to the outflow pipe;
An on-off valve provided in the middle of the bypass pipe,
Detecting means for detecting the flow rate of the engine coolant flowing through the inflow pipe,
Control means for controlling the opening and closing of the on-off valve in accordance with the flow rate of the engine coolant detected by the flow rate detecting means. The control means includes a comparison means for comparing the flow rate of the engine coolant detected by the detection means with a predetermined flow rate, and when the comparison means determines that the flow rate of the engine coolant is larger, The vehicle air conditioner according to claim 1, wherein control for opening the on-off valve is performed.

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