JPS6228004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle air conditioner, and more particularly to a vehicle air conditioner using a heater core as a heat storage device.

Conventionally, vehicle air conditioners include a blower that introduces inside and outside air, an evaporator, a heater core, an air mixer door that adjusts the mixing ratio of cold air and warm air, and blows out conditioned air from an air outlet. It is something. When the full cooler mode is set when riding, the continuous operation of the compressor causes the evaporator temperature to drop rapidly, which causes the cabin temperature to drop sharply. When the temperature of the evaporator further decreases and reaches just before the freezing temperature, the temperature of the evaporator repeats high and low in the low temperature region almost synchronously with the on/off operation of the compressor. As a result, the temperature of the air blown out from the air outlet fluctuates, causing discomfort to the occupant. Additionally, when the vehicle is stopped, the compressor is turned off to reduce the load on the engine during idling, and the doors are opened to get in and out of the vehicle, which increases the temperature of the blown air, causing discomfort to the occupants. Put it away.

The purpose of the present invention is to suppress fluctuations in the temperature of air blown out from an air outlet by using a heater core as a heat storage for cold air and dissipating this cold air when necessary. explain.

1 and 2 are simplified configuration diagrams and circuit diagrams showing one embodiment of a vehicle air conditioner according to the present invention, and in each figure, 1 indicates an outside air port 2, an inside air port 3,
It is a duct having an air outlet 4, and inside thereof a blower 5, an evaporator 6, a heater core 7,
An air mixer door 8 is installed, and the inside and outside air from the blower 5 is cooled by the evaporator 6.The cool air is sent to the heater core 7 and heated by an amount corresponding to the opening degree θ of the air mixer door 8, and the air conditioned in this way is The air is blown out from the air outlet 4. The air mixer door 8 is controlled by an actuator 9, one end of which is connected to a switching transistor 10 and a power amplifying transistor 11, and the other end is grounded, as shown in FIG.

12 is a temperature sensor installed close to the evaporator 6, and the connection point voltage _E1 between the sensor 12 and the resistor 13 is applied to the operational amplifier 15 via the resistor 14.
is supplied to the inverting input side of the On the non-inverting input side of the operational amplifier 15, there is a divided voltage E ₂ between the resistors 17 and 18.
(equivalent to a temperature of about 2°C) is supplied via the resistor 19, and as shown in Fig. 3, when the temperature te of the evaporator 6 decreases and reaches about 2°C, the voltage
E ₁ increases to become E ₁ >E ₂ , and its output voltage V ₄ becomes L level, turning on transistor 10 . The characteristics of this operational amplifier 15 are set so that it becomes H level when the temperature te of the evaporator exceeds approximately 10°C (see Fig. 3).The temperature sensor 12 is connected to the inverting input side of the operational amplifier 16. The output voltage E ₁ is supplied to the non-inverting input side, and the divided voltage E ₃ of the resistors 20 and 21 is supplied to the non-inverting input side.
(equivalent to a temperature of about 10°C) is supplied _, and as shown in _{FIG .}
The level is inverted to the L level, and at this time, the trigger pulse V ₁ is obtained from the differentiating circuit 22 at the subsequent stage of the operational amplifier 16. 23 is a timer circuit that is driven by this trigger pulse V ₁ and sends out an L level output V ₂ over a set time T, and the output V ₂ of this timer circuit 23 is inverted by an inverting circuit 24 and then sent to an integrating circuit. 25 and is supplied to the base of transistor 11 as a sawtooth wave. That is, as shown in FIG. 5a, when the temperature te of the evaporator 6 decreases to below about 0° C., the output voltage V ₀ of the operational amplifier 16 becomes L level.
A trigger pulse V ₁ is sent out from the differentiating circuit 22,
The timer circuit 23 sends out a pulse output V ₂ that is at the L level for a set time period T, and this pulse output V ₂ is inverted by the inverting circuit 24 and integrated by the integrating circuit 25, so that the voltage changes over time. A sawtooth voltage V ₃ is supplied whose value gradually increases, so that the output of the transistor 11 gradually increases.

Therefore, according to the present invention, when the full cooler mode is set at the initial stage of vehicle operation, the compressor is continuously driven and the evaporator 6 is rapidly cooled (see FIG. 6a). At this time, since the input to the actuator 9 is 0, the opening degree θ of the air mixer door 8 is 0, and the cold air from the evaporator 6 is directly blown out from the outlet 4, thereby rapidly cooling the vehicle interior.

Next, the temperature te of the evaporator 6 decreases to 10
When the temperature drops below approximately ℃, V ₀ becomes L level, the timer circuit 23 is activated, and output V ₃ is obtained.
The base input of the transistor 11 gradually increases, the actuator 9 is driven, and the opening degree θ of the air mixer door 8 gradually increases. In this case, the set time period T of the timer circuit 23 is such that the temperature te of the evaporator 6 changes from approximately 10°C to 2°C due to the drive of the compressor.
The opening degree θ of the air mixer door 8 is set slightly longer than the average time required for the temperature to drop to ℃.
becomes close to its maximum value as the temperature te of the evaporator 6 approaches approximately 2°C. For this reason,
The heater core 7 in which the water tank is closed in advance is gradually cooled down and cold air is stored therein.

The temperature te of evaporator 6 further decreases by 2℃
When the output voltage _V4 of the operational amplifier 15 becomes L
level, the transistor 10 turns on, and as a result, the power supply voltage is directly applied to the actuator 9, so the opening degree θ of the air mixer door 8 is set to the maximum value, and in this state, the temperature te of the evaporator 6 rises to 10°C. Output of operational amplifier 15 V ₄
is maintained until it reaches H level. On the other hand, the timer circuit is restored after the set time limit T has elapsed.

In the above operation, when the temperature of the evaporator 6 falls below 2°C and reaches the temperature just before the evaporator 6 freezes, the compressor is turned on and off by the action of a control circuit (not shown), and the temperature te of the evaporator 6 does not drop any further to about 2°C. It repeats high and low temperature in the low temperature range. Such an evaporator 6
At the time of temperature fluctuation S, the temperature of the evaporator 6
When te increases and becomes higher than the temperature th of the heater core 7, the cold air of the heater core 7 is radiated, so temperature fluctuations in the blown air can be suppressed.

Furthermore, when the vehicle is stopped, the doors are opened and the engine is in an idling state, so the rotation of the compressor decreases and the temperature of the evaporator 6 rises. Since heat is radiated from the cold air in step 7, it is possible to suppress the temperature rise of the blown air, and it is also possible to limit the rise in the cabin temperature.

In addition, according to this embodiment, the temperature of the evaporator 6
Although the opening degree θ of the air mixer door 8 has been described as being controlled based on te, it may also be controlled based on the temperature of the air downstream of the evaporator 6 or the temperature inside the vehicle.

Also, the output of the operational amplifier 15 is transferred to the evaporator 6.
When the temperature te rises from 2°C to 10°C, H
I explained that it would restore to the level, but beyond that,
It may be arranged to recover when the temperature reaches a temperature lower than that.

Furthermore, the input supplied to the transistor 11 is not limited to one that increases linearly over time, but may increase in a curved or stepwise manner as shown in FIG.

As explained above, according to the present invention, when the temperature of the evaporator, the temperature of the air downstream of the evaporator, or the temperature inside the vehicle compartment decreases due to the drive of the compressor and becomes equal to or lower than the first set temperature, the magnitude is reduced for the set time period T. A timer circuit that sends out an output that increases over time controls the opening of the air mixer door to gradually cool the heater core, allowing the vehicle interior to be cooled while storing cold. In addition, the opening degree of the air mixer door is set to the maximum value from the time when the temperature further decreases and reaches the second set temperature until this temperature rises to the predetermined temperature, so that the cold air stored in the heater core can be removed. Since heat can be radiated when the temperature of the evaporator or the inside of the vehicle increases, fluctuations in the blowout temperature can be suppressed and the feeling for the occupants can be improved.

[Brief explanation of the drawing]

1 and 2 are simplified configuration diagrams and circuit diagrams showing one embodiment of a vehicle air conditioner according to the present invention, FIGS. 3, 4, 5 a to d, and 6 a to e. is an explanatory diagram for explaining the operation of the above device,
FIG. 7 is a diagram showing another embodiment of the vehicle air conditioner according to the present invention. 5... Blower, 6... Evaporator, 7... Heater core, 8... Air mix door, 9... Actuator, 12... Temperature sensor.

Claims (1)

[Scope of Claims] 1. A vehicle air conditioner comprising at least an evaporator, a heater core that stores cold air in cooler mode, and an air mixer door that controls the amount of air supplied from the evaporator to the heater core. When the air temperature on the downstream side of the evaporator or the temperature in the vehicle compartment decreases due to the drive of the compressor and becomes lower than the first set temperature, a timer circuit that sends out an output that increases in size as time passes at the set time limit controls the air mix door. A control circuit is provided that controls the opening degree so that the cold air is gradually stored in the heater core, and the temperature further decreases until the second temperature is reached.
An air conditioner for a vehicle, characterized in that it is provided with a control circuit that controls the opening degree of an air mixer door to be fixed at a maximum value when a set temperature is reached. 2. When the temperature of the evaporator, the temperature of the air downstream of the evaporator, or the temperature inside the vehicle reaches the second set temperature, the opening degree of the air mixer door is fixed at the maximum value until the temperature rises to approximately the first set temperature. An air conditioner for a vehicle according to claim 1.