JP3191391B2 - Automotive air conditioners - Google Patents

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 compressor.

[0002]

2. Description of the Related Art In recent years, an electric compressor is mounted on an air conditioner for a vehicle, and the compressor speed is controlled independently of the engine speed.

A conventional vehicle air conditioner of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 63-57316, and all of these controls operate a compressor at a high speed if the temperature in the vehicle compartment is high, and control the vehicle. When the room temperature drops, the compressor operates at low speed.

[0004]

However, the power generation capacity of the generator for supplying electric power for driving the compressor is as follows.
Actually, it depends on the engine speed.
An air conditioner having only control as disclosed in Japanese Patent Application No. 57316 requires a physically large generator having a sufficient power generation capacity even when the engine speed is low, and has a problem that it is not practical. I was In addition, if the generator output is used not only for air conditioning but also as a power source for other equipment, and the indoor heat load is large and the power consumption of other equipment is large, the power When the sum of the used amounts exceeds the generator output capacity, the generator output is saturated and the output voltage is extremely reduced, which adversely affects connected devices.

[0005]

In order to solve the above-mentioned problems, an air conditioner for a vehicle according to the present invention measures a duty ratio of the switching element and detects that an output of the generator is saturated. The compressor output saturation detecting means and a compressor control unit for lowering the rotation speed of the electric compressor by detecting that the duty ratio of the switching element has become larger than an allowable value by the generator output saturation detecting means. Things.

[0006]

According to the present invention, with the above-described structure, the saturation of the generator output is quickly detected and the rotational speed of the electric compressor is reduced, so that practical and rapid drop of the voltage due to the saturation of the generator output is prevented. And an air conditioner that does not adversely affect other devices connected to the generator.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a control system of an air conditioner for a vehicle according to an embodiment of the present invention.

FIG. 1 is a control block diagram showing one embodiment of the present invention. The generator 1 is driven from the car engine 2 to the belt 3
And outputs it as electric energy to the first output 4 and the second output 5.
Drive 7 as a power source for driving the electric compressor 6
And the first output 4 is connected to another in-vehicle device. The control device 8 includes a generator output saturation detecting means 9 for detecting the saturation of the output of the generator, and a compressor control unit 11 for controlling the compressor rotation speed based on signals from various sensors 10. The control device 8 also controls various actuators 12 for air conditioning based on the signal from the sensor 10 at the same time. FIG. 2 is an electric circuit diagram of the above-described generator 1 and its periphery. The voltage regulator 13 feeds back the voltage of the first output 4 and
The exciting current flowing through the field winding 14 is controlled by turning on and off a field transistor 15 for controlling the exciting current so that the voltage of the first output 4 is always constant. Then, in order to measure the duty ratio of the field transistor 15, the generator output saturation detection signal 16 is supplied from the collector terminal of the field transistor 15.
Has been taken out. Then, the generator saturation detection signal 16 is input to the generator saturation detection means 9 of FIG. FIG. 3 is an output voltage waveform of the generator saturation detection signal 16. The power generation capacity of the generator 1 generally depends on the engine speed as shown in FIG. Therefore, the allowable electric load is a region indicated by the hatched area in FIG. Therefore, if the electric load is not always kept in the shaded area by any method, it is understood that all the devices connected to the generator 1 are adversely affected.

Next, the operation of the present invention will be described. For example, in FIG. 4, point (a) indicates that the engine speed is 1500.
When the electric load is 600 W at rpm, the waveform of the generator output saturation detection signal 16 at that time has a duty ratio T1 of the field transistor 15 as shown in FIG. When the electric load increases from this state to the points (b) and (c) in FIG. 4, the waveform of the generator output saturation detection signal 16 changes to the field as shown in (b) and (c) in FIG. The duty ratio of the transistor 15 increases to T2 and T3. Also, when the engine speed drops from the point (a) in FIG. 4 to the points (b) ′ and (c) ′, the waveforms of the generator output saturation detection signal 16 also show the waveforms in FIG. As shown in (c), the duty ratio of the field transistor increases. Therefore, as shown in the control flow of this embodiment shown in FIG.
The duty ratio of the field transistor is measured (step 101), and when the duty ratio exceeds the allowable value, the saturation of the generator output is detected (step 102), and the rotational speed of the electric compressor 6 is reduced (step 103).
It is possible to control so that the voltage does not suddenly decrease due to the output saturation of the generator.

[0010]

As described above, the automotive air conditioner of the present invention is driven by the power from the engine, has a single or a plurality of outputs, and has at least a field winding and an excitation flowing through the field winding. An on-board generator having a switching element for controlling current and a voltage regulator for keeping one of the outputs constant by turning on and off the switching element, and an electric compressor having a built-in motor driven by an electric input, A control device that controls at least the rotational speed of the electric compressor according to environmental conditions inside and outside the vehicle, and a driving device that drives the electric compressor according to a control signal from the control device,
The control device measures a duty ratio of the switching element, and detects generator output saturation detecting means for detecting that the output of the generator is saturated. The duty ratio of the switching element is an allowable value by the generator output saturation detecting means. By providing a compressor control unit that reduces the number of revolutions of the electric compressor by detecting that it has become larger, it is practical and prevents a sudden drop in voltage due to saturation of the generator output. An air conditioner that does not adversely affect other devices connected to the air conditioner can be obtained.

[Brief description of the drawings]

FIG. 1 is a control block diagram showing an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of the generator and its periphery.

FIG. 3 is a voltage waveform diagram of the generator saturation detection signal.

FIG. 4 is an output characteristic diagram according to the engine speed of a general generator.

FIG. 5 is a flowchart showing a control flow of a control device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Generator 2 Engine 3 Belt 4 1st output 5 2nd output 6 Electric compressor 7 Drive device 8 Control device 9 Generator output saturation detection means 10 Sensor 11 Compressor control part 12 Actuator 13 Voltage regulator 14 Field winding 15 Field transistor 16 Generator output saturation detection signal

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-121918 (JP, A) JP-A-64-69733 (JP, A) JP-A-1-1311841 (JP, A) 127339 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60H 1/32 623 F04B 49/10 331

Claims (1)

(57) [Claims] 1. A while being driven by the power from the engine, ON of the switching element, an electric compressor for a vehicle generator which controls a voltage to be constant, the vehicle generator and the driving power source by OFF, the electric power generating A vehicle device that uses the power supply as a driving power source, a generator output saturation detecting unit that detects an output saturation state of the on-vehicle generator, and the generator output saturation detecting unit measures ON or OFF time of the switching element. If it is detected that the duty ratio or ON time of the switching element exceeds a predetermined value , priority is given to the operation of the vehicle equipment.
And an air conditioner for a vehicle provided with a compressor control unit for reducing the number of revolutions of the electric compressor.