JPH0245217A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable hot water flow control to be achieved by means of a cheap device by providing such constitution as including a bypass piping detouring a heat exchanger for inducing heat exchange between the cooling water of an internal combustion engine and air, and controlling the passage of cooling water toward the heat exchanger or the bypass piping by means of two closing valves. CONSTITUTION:An air conditioner mounted on a bus body is provided with a hot water circuit 4 including a heater core 2 for heating the inside of a vehicle cabin and a defroster core 3 for preventing frost on front glass. The hot water circuit 4 is sequentially connected to the water jacket of an engine 1 and a cooling water circuit 6 circulating along the water jacket and radiator 5 of the engine 1 and cooling water is circulated there by the operation of a water pump 7. In this case, a bypass piping 9 detouring the heater core 2 is provided as well as provision of a solenoid valve 8 for opening/closing a hot water piping 4a upstream from the heater core 2, and a defroster solenoid valve 10 is pro vided on the way. And these solenoid valves 8, 10 are so designed that when one of these valves 15 is closed, the other one is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air conditioner equipped with a heat exchanger that uses cooling water of an internal combustion engine as a heat source.

Conventional technology] Conventionally, hot water heat exchangers heat the interior of a vehicle by guiding cooling water (hot water) from the engine's cooling water circuit through hot water piping and exchanging heat between the cooling water and air. There is a vehicle air conditioner equipped with.

In the case of a bus vehicle, for example, as shown in FIG. 7, this vehicle air conditioner heats the vehicle interior through a cooling water circuit 102 that circulates between a water jacket (not shown) of an engine 100 and a radiator 101. A hot water circuit 106 is formed in which a heater core 103 for preventing fogging of the windshield and a defroster core 104 for preventing fogging of the windshield are connected by hot water piping 105, and a water pump 107 supplies cooling water to the heater core 103 and defroster core 104. There is.

This hot water circuit 106 is provided with a two-way valve 10B for keeping the hot water pipe 105 closed during the summer when heating is not required for a long period of time. Preheater 10 for heating cooling water when the temperature of the cooling water is low
9 is provided.

Note that 110 is a thermostat for keeping the coolant temperature of the engine 100 constant, and 111 is a blower for blowing air warmed by the heater core 103 into the vehicle interior.

In this way, in the heater core 103 that uses the cooling water of the engine 100 as a heat source to operate the 111 chambers in the vehicle interior, the amount of cooling water supplied to the heater core 103 is constant, and the heating capacity of the heater core 103 is controlled by controlling the air volume of the blower 111. There is a method of controlling the air volume of the blower 111 and a method of controlling the heating capacity of the heater core 103 by controlling the amount of cooling water supplied to the heater core 103 using a flow control valve (not shown).

[Problem B to be solved by the invention] However, the heater core 1 can only be controlled by controlling the air volume of the blower 111.
When controlling the heating capacity of 03, when in low capacity mode, the temperature of the air blown into the passenger compartment becomes high, and the air velocity in the passenger compartment is low, so there is less agitation of the air in the passenger compartment and the temperature distribution deteriorates. could cause discomfort.

In addition, if a flow control valve is used, the cost will be very high, and in the case of low capacity mode, it is necessary to control the opening of the flow control valve to 5 to 10% of the fully open state, and the flow control The problem was that it was difficult to control the valve.

Note that a solenoid valve is provided in the hot water pipe 105, and the solenoid valve is set to 0.
There is a method of controlling the amount of cooling water by N-OFF control, but in this case, the impact (pressure) of the cooling water when the solenoid valve is turned OFF causes the hot water pipe 105 and the heater pump 10 to
7. There is a risk of damage to the joint of the piping or the heat exchanger t*3, so it is generally not used for automotive applications.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an air conditioner that is inexpensive, safe, and can easily control the flow rate of hot water to a heat exchanger.

[Means for Solving the Problems] In order to achieve the above object, the present invention is connected to a cooling water circuit of an internal combustion engine by a hot water pipe, and provides cooling water and air for the internal combustion engine supplied via the hot water pipe. a heat exchanger that exchanges heat with the heat exchanger, and connects upstream and downstream of the heat exchanger,
a bypass pipe that bypasses the heat exchanger; a first on-off valve that opens and closes the hot water pipe and is provided downstream of the branch point between the bypass pipe and the hot water pipe and upstream of the heat exchanger; a second rM closing valve that is provided in the bypass piping and opens and closes the bypass piping; and a first Wf4 closing valve that opens the other when one of the first rM closing valve and the second ftR closing valve is closed. and a control circuit for controlling opening and closing of the second on-off valve.

[Function] The present invention having the above-mentioned configuration is capable of controlling the first rM by the control circuit.
The bypass piping is shut off by closing the valve and opening the second opening valve.

Thereby, the cooling water supplied from the internal combustion engine cooling water circuit flows to the heat exchanger through the hot water pipe provided with the first fjFI closing valve, and then returns to the internal combustion engine cooling water circuit again.

Further, the hot water piping is shut off upstream of the heat exchanger by opening the first opening/closing valve and opening the second opening/closing valve by the control circuit.

Thereby, the cooling water supplied from the cooling water circuit of the internal combustion engine flows through the bypass pipe, and then returns to the cooling water circuit of the internal combustion engine again. Therefore, in this case, cooling water is not supplied to the heat exchanger.

[Effects of the Invention] According to the present invention, the control circuit alternately controls the opening and closing of the first fmm valve and the 211th FI closing valve, and controls the amount of cooling water to the heat exchanger by controlling the control time. Can be done.

In addition, the first on-off valve and the second W4 closing valve are arranged so that when either one of the first on-off valve and the second W4 closing valve is closed, the other is opened.
Since the opening control of the opening/closing valve is performed, even if one of the opening/closing valves is closed, the impact (pressure) of the cooling water can be released to the piping provided with the other opening/closing valve. Therefore, turn off the solenoid valve like before! There is no impact from the cooling water when the hot water pipes and various functional parts are affected by the impact.

[Example] Next, an air conditioner of the present invention will be described based on an example shown in the drawings.

FIG. 1 shows a hot water circuit of an air conditioner applied to a bus vehicle.

The air conditioner for a bus of this embodiment has a cooling cycle that dehumidifies and cools the interior of the vehicle using a well-known refrigeration cycle (not shown), and a cooling cycle that uses cooling water (hot water) from the engine 1 as a heat source to heat the interior of the vehicle and use the windshield. It has a heating cycle that prevents fogging.

As shown in FIG. 1, the heating cycle is carried out by a hot water circuit 4 equipped with a heater core 2 which is a heat exchanger of the present invention for heating the interior of the vehicle, and a defroster core 3 for preventing fogging of the windshield. It is configured.

The heater core 2 and the defroster core 3 are hot water type heat exchangers that warm the air by exchanging heat between hot water and air.

In the hot water circuit 4, the heater core 2 and the defroster core 3 are sequentially connected to a cooling water circuit 6 which circulates through the water jacket (not shown) of the engine 1 and the radiator 5 through a hot water pipe 4a, and a water pump provided in the hot water pipe 4a. 7 supplies cooling water for the engine 1 to the heater core 2 and defroster core 3.

The hot water circuit 4 is provided with a main solenoid valve (first opening 111 valve of the present invention) 8 that opens the hot water pipe 4a upstream of the heater core 2, and connects the L flow of the main solenoid valve 8 with the downstream of the heater core 2. A bypass pipe 9 is provided which connects the heater core 2 to bypass the heater core 2, and the bypass pipe 9 is provided with a defroster solenoid valve (second on-off valve of the present invention) 10 which opens the bypass pipe 9.

A preheater 11 is provided downstream of the main electromagnetic valve 8 (upstream of the heater core 2) for heating the cooling water when the temperature of the cooling water supplied from the water jacket is low.

The main solenoid valve 8 and the defroster solenoid valve 10 are
The main solenoid valve 8 is operated by a control circuit (see Fig. 2) 12, which will be described later, to open when energized and close when de-energized.
When either one of the defroster solenoid valves 10 is turned off, the energization is controlled so that the other is opened.

The heater core 2 is disposed together with an evaporator 13 of the refrigeration cycle in a blower duct 14 for blowing air into the vehicle interior. A blower fan 15 is disposed upstream of the blower duct 14 to blow air to the heater core 2 and the evaporator 13 and to blow out conditioned air into the vehicle interior.

The defroster core 3 is disposed within a defroster duct 16 that has a plurality of air outlets (not shown) that open toward the windshield of the bus vehicle.

A defroster fan 17 is disposed within the defroster duct 16 for blowing air to the defroster core 3 and blowing hot air to the windshield.

The blower fan 15 and the defroster fan 17 are driven by a blower motor 15a and a defroster motor 17a, and are controlled to be energized by the control circuit 12, respectively.

Note that the coolant circuit 6 is provided with a thermostat 18 for keeping the coolant temperature of the engine 1 constant.

The electric circuit for operating the heating cycle will be explained based on the electric circuit diagram shown in FIG. 2.

The control circuit 12 is powered by an onboard battery 19 and is activated when an air conditioner switch 20 or a defroster switch 21 is turned on, and includes an inside temperature thermistor 22 for detecting the vehicle interior temperature, an outside temperature thermistor 23 for detecting the outside temperature, and an interior temperature setting device. The operation mode of the cooling/heating cycle is determined using the change in the combined resistance value of the thermistor 24 as an input signal.

A water temperature thermistor 25 for detecting the temperature of cooling water supplied to the preheater 11 and a blowout temperature thermistor 26 for detecting the temperature of air blown into the vehicle interior are connected to the control circuit 12, and each detected resistance value is inputted. At the same time, relay 27.
28 and 29.30.31 via two-auta bomb 7
, a main solenoid valve 8, a defroster solenoid valve 10, a blower motor 15a, and a defroster motor 17a are connected.

The blower motor 15a is set to the old mode (high speed rotation) via the 16 mode register 32 and the LO mode register 33.
, He mode (medium speed rotation), [0 mode (low speed rotation)
Three operation modes are set, each with 30 relays.
Along with old mode relay 34, He mode relay 35,
[It is driven in each operation mode by energizing the 0 mode relay 36.

The main solenoid valve 8 and the defroster solenoid valve 10 control the amount of cooling water supplied to the heater core 2 when performing heating operation in the [0 mode].
By operating OFF, the 0
N-OFF control is performed.

Next, the main solenoid valve 8 and the defroster solenoid valve 10 are
The operation of the control circuit 12 when performing N-OFF control will be explained based on the flowcharts shown in FIGS. 4 to 6.

(a) When shifting from cooling or ventilation mode to ON-OFF control of the main solenoid valve 8 and the defroster solenoid valve 10 (see FIG. 4).

First, in step 1, LO mode heating is selected from cooling or ventilation mode, and the process proceeds to step 2.

In step 2, the automatic bomb 7 and main solenoid valve 8 are energized, and the process proceeds to step 3.

In step 3, it is determined whether the cooling water temperature detected by the water temperature thermistor 25 is 40° C. or higher.

If the determination result in step 3 is NO, then in step 4 the power supply to the blower motor 15a is stopped, and the process returns to step 3.

If the judgment result in step 3 is YES, step 5
The blower motor 15a is energized via the relay 30 and the [0 mode relay 36, and the blower motor 1
After driving 5a in the Lo mode, the process proceeds to step 6.

In step 6, it is determined whether one minute has passed after the blower motor 15a is energized.

If the determination result in step 6 is NO, step 6 is repeated.

If the judgment result in step 6 is YES, step 7
In this step, ON-OFF control of the main solenoid valve 8 and the defroster solenoid valve 10 is performed.

(b) When shifting from the old mode or He mode heating to ON-OFF control of the main solenoid valve 8 and the defroster solenoid valve 10 (see FIG. 5).

By selecting LO mode heating in step 8,
The blower motor 15a is driven in the 0 mode via the relay 30 and the 0 mode relay 36, and the process then proceeds to step 9.

In step 9, main solenoid valve 8 and defroster solenoid valve 1 are
0N-Off' control is performed.

(c) When the defroster switch 21 is turned on during cooling or ventilation mode (see Figure 6).

After the defroster switch 21 is turned on in the cooling or ventilation mode in step 10, the process proceeds to step 11.

In step 11, the water pump 7 and the defroster solenoid valve 10 are energized, and the process proceeds to step 12.

At this time, the main solenoid valve 8 is not energized.

In step 12, the defroster motor 17a is energized.

Next, the operation of the air conditioner accompanying the ON-OFF control of the main solenoid valve 8 and the defroster solenoid valve 10 according to the present invention will be described.

Air conditioner switch 20 or defroster switch 21
The control circuit 12 is activated by turning on the power, and the heating/cooling mode is determined.

(d) When switching to heating mode after cooling or ventilation mode is selected.

By energizing the water pump 7 and the main solenoid valve 8 by the control circuit 12, cooling water is supplied from the water jacket of the engine 1 to the heater core 2.

At this time, if the cooling water temperature detected by the water temperature thermistor 25 is 40° C. or lower, the cooling water is heated by the operation of the preheater 11 and supplied to the heater core 2 .

Note that the power supply to the blower motor 15a is stopped when the cooling water temperature detected by the water temperature thermistor 25 is 40° C. or lower. Therefore, in this case, the cooling water only passes through the heater core 2 and is not blown into the vehicle interior.

Thereafter, when the temperature of the cooling water supplied to the heater core 2 reaches 40°C or higher, *i is applied to the blower motor 15a via the relay 30 and the Lo mode relay 36, and the blower fan 15 is operated in the 1.0 mode. warm air is blown into the vehicle interior.

The cooling water that has passed through the heater core 2 is supplied to the defroster core 3, and then returns to the overjacket of the engine 1 again.

After one minute has passed after the blower motor 15a is energized, the main solenoid valve 8 and the defroster solenoid valve 10 are turned ON-OF.
F control is performed. This 1 minute time setting is set so that the main solenoid valve 8 and the defroster solenoid valve 10 are set to zero immediately after the blower motor t5a is energized.
Since the amount of cooling water supplied to the heater core 2 is small, the heat amount of the cooling water is absorbed by the heat capacity of the heater core 2, and it takes time for the Suita temperature in the vehicle interior to rise.

Therefore, the main solenoid valve 8 and the defroster solenoid valve 10 are turned OFF for one minute after the blower motor 15a is energized.
By flowing the cooling water to the heater core 2 without performing any control, the water in the hot water pipe 4a and the heater core 2 is replaced with hot water, and the heater core 2 itself is warmed to speed up the rise in the blowing temperature.

In addition, instead of setting the time for 1 minute, the blowout temperature thermistor 2
When the air temperature detected by 6 reaches a certain temperature or higher, the main solenoid valve 8 and the defroster solenoid valve 10 are turned 0N-O.
After 91 minutes of FF$ control, the main solenoid valve 8 and the defroster solenoid valve 10 are turned OFF.
The amount of cooling water supplied to the heater core 2 is controlled by controlling a portion of the cooling water to flow into the bypass pipe 9.

The amount of cooling water supplied to the heater core 2 is controlled by the main solenoid valve 8.
In ON-OFF control of the defroster solenoid valve 10, control can be performed by changing the 311 electric time to the main solenoid valve 8.

Therefore, the energization time to the main solenoid valve 8 is gradually increased,
Finally, the heating capacity of the heater core 2 can be increased by turning it on all the time.

(E) When the old mode or He mode heating is selected and then the mode shifts to LO mode fubo.

In this case, since heating operation is being performed, the main solenoid valve 8 is directly connected to the
The amount of cooling water supplied to the heater core 2 is controlled by performing ON-OF'F control of the defroster solenoid valve 10.

(f) When the defroster switch 21 is turned on during cooling or ventilation mode.

By turning on the defroster switch 21, the driver pump 7, the defroster solenoid valve 10, and the defroster motor 1 are activated.
7a is energized. Thereby, the cooling water supplied from the water jacket of the engine 1 is guided to the defroster core 3 through the bypass pipe 9. By energizing the defroster motor 17a, the defroster fan 17 is driven, and air warmed by the defroster core 3 is blown onto the windshield.

In this case, when cooling water flows through the heater core 2, if the mode is in the cooling mode, the blowing temperature will rise and the cooling capacity will be reduced, and if the mode is in the blowing mode, warm air will be blown into the vehicle interior. Therefore, when the defroster switch 21 is turned on in the cooling or ventilation mode, the main solenoid valve 8 is not energized, and therefore all the cooling water supplied from the water jacket of the engine 1 flows to the defroster core 3.

As mentioned above, by providing the bypass pipe 9 in the hot water circuit 4 that constitutes the heating cycle so that the cooling water supplied from the water jacket of the engine 1 can bypass the heater core 2 and pass through, it is possible to The amount of cooling water supplied to the heater core 2 can be easily controlled by simply controlling the main electromagnetic valve 8 and the defroster electromagnetic valve 10 to zero or F without using an expensive flow control valve.

Therefore, by performing ON-OFF control of the main solenoid valve 8 and the defroster solenoid valve 10 when the blower motor 15a is in the 0 mode, an amount of cooling water suitable for the capacity of the blower motor 15a can flow to the heater core 2.

As a result, the temperature of the air blown into the vehicle interior can be controlled to an appropriate temperature, and the discomfort caused to passengers can be significantly reduced.

In addition, by alternately turning the main solenoid valve 8 and the defroster solenoid valve 10 OFF, the impact (pressure) of the cooling water that occurs when the main solenoid valve 8 or the defroster solenoid valve 10 is turned off can be released. , the hot water pipe 4a, the water pump 7, the joint portion of the hot water pipe 4a, the heater core 2, the defroster core 3, etc. can be prevented from being damaged.

As a result, the amount of cooling water to the heater core 2 can be controlled safely and easily using a low-cost solenoid valve as in this embodiment.

Further, in the case of this embodiment, since cooling water always flows through the defroster core 3 even when performing ON-OFF control of the main solenoid valve 8 and the defroster solenoid valve 10, the defroster capacity shortage can be resolved.

(Modified example) In the above embodiment, when shifting to the heating mode after the cooling or blowing mode is selected, the blower motor 15a
Although the time setting is set for one minute after energization, this time setting does not need to be limited to one minute because it is determined by the heat capacity of the heater core 2 or the amount of cooling water.

In addition, although a time setting of 1 minute is provided in this embodiment, it is not necessarily necessary to set the time, and the main solenoid valve 8 and the defroster solenoid valve 10 are turned off immediately after the blower motor 15a is energized.
N-OFF control may also be performed.

Although the air conditioner of the present invention is applied to a bus vehicle, it may also be applied to a railway vehicle, a ship, or a stationary (factory, etc.) air conditioner.

In this embodiment, one heater core 2 is illustrated as the heat exchanger of the present invention, but a plurality of heater cores may be provided.

Although the main solenoid valve 8 and the defroster solenoid valve 10 are shown as on-off valves that open and close the hot water pipe 4a or the bypass pipe 9, it is not necessary to limit the present invention to solenoid valves.

[Brief explanation of the drawing]

Figure 1 shows the hot water circuit of an air conditioner applied to a bus vehicle.
Fig. 2 is an electric circuit diagram configuring the heating cycle, Fig. 3 is an explanatory diagram showing the basic operation of the main solenoid valve and defroster solenoid valve, Figs. 4 to 6 are flow charts showing the operation of the control circuit, and Fig. 7 The figure shows a hot water circuit of an air conditioner, which is an example of the prior art. In the figure 2... Heater core (heat exchanger of the present invention) 8... Main solenoid valve (1st rM valve closed) 9... Bypass piping 10... Defroster solenoid valve (2nd rJM valve closed) 12...
...Control circuit diagram 3

Claims (1)

[Scope of Claims] 1) (a) A heat exchanger connected to a cooling water circuit of an internal combustion engine by a hot water pipe, and for exchanging heat between the cooling water of the internal combustion engine supplied via the hot water pipe and air; , (b) bypass piping that connects upstream and downstream of the heat exchanger and bypasses the heat exchanger; (c) downstream of the branch point between the bypass piping and the hot water piping, and the heat exchanger (d) a second on-off valve that is provided on the bypass piping and opens and closes the bypass piping; (e) the first on-off valve and the An air conditioner comprising: a control circuit that controls the opening and closing of the first on-off valve and the second on-off valve so that when either one of the second on-off valves is closed, the other one is opened.