JPH05169967A - Air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To provide an air conditioner for vehicle of which the maximum electric power consumption at beginning of heating operation can be reduced. CONSTITUTION:The PTC heater unit 21a of a PTC heater 20 arranged in a duct 19 is electrified by ON of a main switch 33, nearly simultaneously with this electrification a blower motor 7 is driven so as to feed air by means of a blower fan 8, and hot air is blown off from a feet side blowoff port 18. After the lapse of a set time (10-30 second) in which the peak of electric power consumption is passed by, the other PTC heater unit 21b is electrified by a timer circuit. Temperature rise of engine cooling water is detected by a water temperature sensor 41, hot air can be supplied by heat exchange in a heater core 10, and then electrification to the PTC heater 20 is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner equipped with an electric heating element as an auxiliary heat source at the start of heating operation.

[0002]

2. Description of the Related Art When a hot water heater utilizing waste heat of engine cooling water is used as a heat source for heating an air conditioner for a vehicle, since the temperature of the engine cooling water is low at the time of engine start, an energizing heating element is used as an auxiliary heat source. The hot air is supplied to the passenger compartment from the beginning of the heating operation. Currently, a positive temperature coefficient thermistor (hereinafter P
TC thermistor) is used.

[0003]

However, the PTC thermistor as the energization heating element is usually used stably in the vicinity of the Curie point, and it is stable when the Curie point is reached after energization. An excessive current of about 3 to 2 times flows. Therefore, when a plurality of heaters using the PTC thermistor as a heat source are used at the same time, the maximum power consumption becomes extremely large, the charge and discharge balance of the battery deteriorates, and the electric system may malfunction or trouble may occur. is there. Further, there is a problem in that sufficient heating capacity cannot be exhibited if the power consumption is kept low. The present invention has been made to solve the above problems, and an object of the present invention is to provide a vehicle air conditioner that can reduce the maximum power consumption at the time of starting heating operation.

[0004]

Means for Solving the Problems As a concrete means for solving the above problems, in a vehicle air conditioner equipped with an electric heating element as an auxiliary heat source at the start of heating operation, the heating capacity of the electric heating element is There is provided an air conditioning system for a vehicle, which is provided with an energization control circuit for controlling energization of the energization heating element so as to gradually increase.

[0005]

According to the above vehicle air conditioner, when the auxiliary heating element is used at the time of starting the heating operation, the energization control circuit controls the energization so as to gradually increase the heat generation capacity of the energization heating element, thereby reducing the maximum power consumption. Keep it low.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a vehicle air conditioner. An air inlet 6 communicating with the outside air inlet 4 or the inside air inlet 5 by switching the inside / outside air switching damper 3 is provided at one end of the duct 2 forming the outer shell of the vehicle air conditioner 1. A blower fan 8 driven by a blower motor 7 is provided corresponding to the above. Inside the duct 2, in addition to the blower fan 8, an evaporator 9 and a heater core 10 of a hot water heater are sequentially arranged toward the downstream side of the air flow. An air mix damper 11 is attached to the heater core 10.

At the other end of the duct 2, a defroster outlet 12 and a ventilation outlet 13 are provided.
And the heat outlet 14 is formed. The defroster outlet 12 has a def damper 15, the ventilation outlet 13 has a vent damper 16, and the heat outlet 1
Heat dampers 17 are arranged in the respective Nos. further,
A duct 19 having a foot outlet 18 is communicated with the heat outlet 14, and a PTC heater 20 is arranged in the duct 19.

As shown in FIG. 2 (a), the PTC heater 20 has radiating fin structures 23 arranged above and below a PTC thermistor 22, and has a current-carrying (+) terminal 24 and a current-carrying (-).
A plurality of PTC heater units 21 having terminals 25 are connected in parallel or used, or two PTC heater units 21 are used as shown in FIG. 2B and one of them is turned upside down. A laminate is used in which the energization (+) terminal 24 is common.

FIG. 3 shows two PTC heater units 21.
It is a schematic control circuit for controlling the switching of a and 21b stepwise. A power supply circuit 32 via a main switch 33 is connected to the control amplifier 31, and the drive circuit 34 of the PTC heater unit 21a and the PTC heater 21 are connected from the power supply circuit 32.
The drive circuit 35 of b is branched in parallel. The drive circuit 34
A relay drive circuit 3 for interposing relays 36 and 37 in series with each other and driving the relays 36 and 37, respectively.
8 and 39 are connected to a timer circuit (not shown) in the control amplifier 31. Others 40 are fuses, and 41 is a water temperature sensor for detecting the engine cooling water temperature.

The operation of the vehicle air conditioner 1 having the above structure at the start of the heating operation will be described below. The operation other than the start of the heating operation is outside the scope of the present invention and is a well-known matter, so the description thereof will be omitted. When the heating operation is started in a cold region or when the engine cooling water temperature is low, the air passing through the heater core 10 remains cool and the heat outlet 1
4 flows into the duct 19. For this reason, when the main switch 33 is turned on, the PTC heater unit 21a of the PTC heater 20 arranged in the duct 19 is energized, and after the elapse of a predetermined time (10 to 30 seconds) after the peak of power consumption, the timer circuit PTC heater unit 21
Drive b. The blower motor 7 operates almost at the same time as the PTC heater unit 21a is energized to supply air by the blower fan 8 to blow warm air from the foot outlet 18. When the engine temperature of the engine cooling water is detected by the water temperature sensor 41 and the hot air can be supplied by the heat exchange in the heater core 10, the driving of the PTC heater 20 is stopped.

FIG. 4 (a) is a graph showing the power consumption characteristic after the heating operation is started. The maximum power consumption characteristic is shown in FIG. 4 (b) in comparison with the power consumption characteristic when two PTC heater units are simultaneously energized. The power consumption value Wmax can be greatly reduced. Further, the vehicle air conditioner 1 of the above-described embodiment can obtain a large heating capacity by using the PTC heater 20 in combination while the engine cooling water temperature is rising, and a vehicle equipped with a diesel engine with a low engine cooling water temperature rising degree. Even in, sufficient heating capacity can be obtained. In addition, even in a vehicle equipped with a gasoline engine, which has a large amount of cooling water heat radiation, the startup performance at the start of heating operation can be significantly improved.

In the above embodiment, the PTC heater is provided with two PTC heater units, but three or more PTC heater units are used.
A PTC heater equipped with a heater unit can be used. In this case, the PTCs that are sequentially driven after the elapse of a predetermined time
The number of heater units may be increased, or a plurality of PTC heater units may be energized from the beginning of operation in accordance with the engine cooling water temperature.

[0013]

The present invention has the above-mentioned structure, and when the auxiliary heating element is used at the start of the heating operation, the energization control circuit controls the energization so as to gradually increase the heating capacity of the energization heating element, and the maximum Since the power consumption can be suppressed to a low level, there is an effect that it is possible to eliminate the fear that the charge / discharge balance of the battery is deteriorated and the electric system becomes out of order or trouble occurs.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a vehicle air conditioner according to the present invention.

FIG. 2 is a perspective view of a PTC heater.

FIG. 3 is a schematic control circuit of a PTC heater.

FIG. 4 is a graph showing power consumption characteristics of a PTC heater.

[Explanation of symbols]

1 ... Vehicle air conditioner, 20 ... PTC heater, 21,2
1a, 21b ... PTC heater unit, 22 ... PTC
A thermistor (electric heating element), 23 ... radiating fin structure,
31 ... Control amplifier, 34, 35 ... Drive circuit, 38, 3
9 ... Relay drive circuit.

Claims (1)

[Claims] 1. A vehicle air conditioner having an energization heating element as an auxiliary heat source at the start of heating operation, in which energization control is performed to control energization of the energization heating element so as to gradually increase the heat generation capacity of the energization heating element. A vehicle air conditioner characterized by being provided with a circuit.