JPH06103137B2 - Vehicle freezer control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for controlling the temperature of a freezer used in a refrigeration vehicle or the like, and more particularly to a device for controlling a compressor of a cooler.

[Prior Art] A conventional temperature control device will be described with reference to FIG. Reference numeral 1 denotes a vehicle engine, which is a first engine via a first electromagnetic clutch 2a.
Is connected to the compressor 3a. 4 is an AC motor,
Electric power is supplied from a commercial power source 6 via a contactor 5, and is connected to a second compressor 3b via a second electromagnetic clutch 2b. Reference numeral 7 denotes a cooler, which is connected to the first compressor 3a via the first check valve 8a and to the second compressor 3b via the second check valve 8b.
The first check valve 8a and the second check valve 8b are adapted to open with the operation of the first electromagnetic clutch 2a and the second electromagnetic clutch 2b, respectively. Reference numeral 9 is a relay sequence circuit, which is connected as shown in the figure. In this circuit, 9a ₁ and 9a ₂ are input terminals, 9b ₁ and 9b ₂ are output terminals, 9c ₁ is a first relay, and 9c ₂
Is a second relay, 9d ₁ is a first clutch coil, 9d ₂ is a second clutch coil, 9e is a contactor coil, and 9S is a contactor coil 9e switch. Further, 10 is a temperature detection circuit mainly composed of a temperature sensor, which detects when the temperature of the freezer becomes a predetermined value or more (below a predetermined value),
Send a command to close (open) the relay 9c ₁ or the second relay 9c ₂ . Reference numeral 11 is a DC power supply circuit, which is connected to the input terminals 9a ₁ and 9a ₂ . In the above configuration, the temperature of the freezer while the vehicle traveling command to the first relay 9c ₁ from the temperature detection circuit 10 becomes more than any preset temperature is sent, the first clutch coil 9d by the relay 9c ₁ is closed ₁ is excited, the first electromagnetic clutch 2a is activated, and the first check valve 8a is opened.
Therefore, the rotation of the vehicle engine 1 depends on the first compressor 3a.
Then, the compressor 3a operates, the compressed refrigerant is sent to the cooler 7, and the freezer is cooled. Further, when the temperature of the freezer falls below an arbitrary set temperature, a command is sent from the temperature detection circuit 10 to the first relay 9c ₁ , the relay 9c ₁ opens, and the excitation of the first clutch coil 9d ₁ is released, The operation of the first electromagnetic clutch 2a is stopped and the first check valve 8a is closed. Therefore, the rotation of the vehicle engine 1 is not transmitted to the first compressor 3a, the first compressor 3a is stopped, and the cooling operation of the freezer is stopped.

Next, when the freezer is operated while the vehicle is stopped, the switch 9S is turned on, the contactor coil 9e is excited, and the contactor 5
When is turned on, the motor 4 rotates. Here, when the temperature of the freezer exceeds an arbitrary set temperature, a command is sent from the temperature detection circuit 10 to the second relay 9c ₂ , and this relay 9c ₂
c ₂ is closed and the second clutch coil 9d ₂ is excited. Therefore, the second electromagnetic clutch 2b operates and the second check valve 8b
Opens. As a result, the rotation of the AC motor 4 is transmitted to the second compressor 3b, the compressor 3b is operated, the compressed refrigerant is sent to the cooler 7, and the freezer is cooled. Further, when the temperature of the freezer falls below an arbitrary set temperature, a command is sent from the temperature detection circuit 10 to the second relay 9c ₂ , the relay 9c ₂ opens, and the excitation of the second clutch coil 9d ₂ is released. . Therefore, the operation of the second electromagnetic clutch 2b is stopped, and the second check valve 8b is closed. This stops the cooling of the freezer.

[Problems to be Solved by the Invention] Meanwhile, the above-mentioned conventional device has the following drawbacks.

Two systems of compressors, one using the vehicle engine and one using the AC motor, are required, which complicates the structure and increases the cost.

When the vehicle engine is rotating, this cooling capacity is limited by the engine speed.Therefore, when the vehicle is operating at low speed, such as during low speed operation or idling operation without commercial power supply, the cooling capacity is greatly increased. descend.

When the vehicle engine is rotating and when the vehicle engine is stopped, the cooling capacity is controlled only by the so-called ON-OFF control of the compressor without frequency control using the controller.
The temperature of the freezer cannot be smoothly controlled.

The present invention has been made in order to eliminate the above-mentioned problems, and an object of the present invention is to make it possible to use a single compressor for both vehicle engine use and AC motor use, thereby simplifying the structure. , A low-cost on-vehicle freezer control device is provided, and further, the on-vehicle freezer control device is capable of controlling the cooling capacity both when the vehicle engine is rotating and when the vehicle engine is stopped without lowering the cooling capacity even when the vehicle engine rotates at low speed. Is to provide.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a vehicle-mounted freezer control device according to the present invention temporarily converts the rotational force of a vehicle engine into an AC voltage by an AC generator, and converts the AC voltage into an automatic voltage. A controller composed of a regulator and an inverter changes the frequency to a desired frequency, and this output voltage rotates an AC motor that is operated by the voltage from the commercial power supply when the vehicle engine is stopped. The compressor of the cooler is operated by the rotation of the AC motor.

Further, the desired frequency is obtained based on the temperature difference between an arbitrary set temperature and the freezer temperature.

Then, in order to make the rise of the AC motor smooth, it is preferable to turn on the compressor several seconds after turning on the switch of the controller.

Furthermore, when the engine speed decreases when the vehicle engine is used, the AC generator speed also decreases, and it is difficult to obtain the rated output at the minimum speed because of the relationship between the AC generator and the engine output. When an electric motor is used, if the frequency of the input voltage is constant and the applied voltage drops, it becomes impossible to operate due to overcurrent.Therefore, the output voltage value or rotation speed of the AC generator is detected, and the output voltage of this AC generator or It is preferable to reduce the output frequency of the controller when the rotation speed becomes equal to or lower than a predetermined value.

[Embodiment] A first embodiment of the present invention will be described below with reference to FIG. In the figure, the components corresponding to those of the conventional one are indicated by the same symbols as in FIG. Reference numeral 12 is an AC generator, which is directly connected to the vehicle engine 1, and the output voltage is input to a controller 13 including an automatic voltage regulator and an inverter. Further, the AC voltage output from this controller is applied to the commercial power supply 6 and the changeover switch 14 and the contactor 5
Is input to the AC motor 15 via. Reference numeral 16 is a compressor, which includes an AC motor 15 and a cooler 7 via an electromagnetic clutch 17.
Connected with. 18 is a relay sequence circuit, the first switch 18S ₁ for performing ON · OFF controller 13, a switch coil 18a for operating the electromagnetic clutch 17, the contactor coil 18b to actuate the contactor 5 are connected in parallel, the clutch coil A second switch 18S ₂ and a third switch 18S ₃ are connected in series to 18a, and a fourth switch 18S ₄ and a fifth switch 18S ₅ are connected in series to the contactor coil 18b. The first switch 18S ₁ , the fourth switch 18S ₄ , and the second switch 18S
_{The second} and fifth switches 18S ₅ are linked together. 19
Is a control circuit for slowly increasing each value of the AC voltage and its frequency output from the controller 13 over a predetermined time after the controller 13 is turned on to a predetermined value. A temperature detecting means for detecting the temperature (means equivalent to the temperature detecting circuit 10 in FIG. 3) is built in. Based on the temperature detected by the temperature detecting means, the control circuit 19 sends a control command to the controller 13 and also the second switch 18S ₂ and the third switch 18
With respect to S ₃ , ON and OF of the electromagnetic clutch 17 as described later
Send a control signal to control F.

Further, the controller 13 is controlled by a microcomputer or the like (not shown) based on a command from the control circuit 19.

Next, a second embodiment will be described with reference to FIG.
In the figure, the components corresponding to those in the first embodiment are designated by the same reference numerals as those in FIG. Reference numeral 20 denotes a frequency control device which detects the output voltage value of the AC generator 12 and reduces the output frequency of the controller 13 when the output voltage value becomes equal to or lower than a predetermined value.

[Operation] The operation of the first embodiment having the above configuration will be described.
During one rotation of the vehicle engine, this rotation causes the AC generator 12
Generates power and outputs an AC voltage to the controller 13.
Now activate the selector switch 14
The controller 13 is turned on when the contact position shown in FIG. 1 for connecting the contactor 13 and the contactor 5 is switched and the first switch 18S ₁ is turned on.
Based on the control command from, the respective values of the AC voltage and its frequency output from the controller 13 slowly increase over a predetermined time until they reach predetermined values. Further, the fourth switch 18S ₄ is turned on in cooperation with the first switch 18S ₁ , the contactor coil 18b is excited, and the contactor 5 operates. Therefore, the AC motor 15 does not have the electromagnetic clutch 17 yet, so that the AC motor 15 can be started smoothly with no load. A few seconds after the first switch 18S ₁ is turned on, when the third switch 18S ₃ is turned on by a control command from the control circuit 19, the clutch coil 18a is excited and the electromagnetic clutch 17 is activated. As a result, the rotation of the AC motor 15 is transmitted to the compressor 16, the compressor 16 operates, and the compressed refrigerant compresses the cooler 7.
And the freezer is cooled. Here, when it is detected that the temperature inside the freezer becomes higher than a predetermined set temperature by the temperature detection means built in the control circuit 19,
The control circuit 19 sends a command to the controller 13 to increase only the frequency of the AC voltage output from the controller 13. Therefore, AC motor 15 rotates at high speed, the cooling capacity is increased, and the temperature of the freezer is lowered. Further, as the detected temperature approaches the set temperature, a command is sent from the control circuit 19 to the controller 13 to reduce the output frequency, the rotation speed of the AC motor 15 is lowered, and the detected temperature is equal to or lower than the set temperature. If it becomes, control circuit
The control command of 19 causes the output voltage from the controller 13 to become zero volt, so that the AC motor 15 stops, and at the same time, the control circuit 19 sends a command to the third switch 18S ₃ to turn off this switch 18S _3. Then, the third switch 18S ₃ is turned off, the clutch coil 18a is demagnetized, the electromagnetic clutch 17 stops operating, and the compressor 16 stops operating. When the temperature of the freezer rises again and the detected temperature exceeds the set temperature, the control circuit as described above.
By the control command from 19, the output voltage from the controller 13 and each value of its frequency slowly rises to a predetermined value over a predetermined time, so the AC motor 15 starts up smoothly, and after a few seconds, this control is performed. In response to a command from the circuit 19, the third switch 18S ₃ is turned on and the clutch coil 18a
Is excited, and the electromagnetic clutch 17 operates. Therefore, the compressor 16 operates and the freezer is cooled.

Further, when the vehicle engine is stopped, the commercial power source 6 and the contactor 5 are connected by switching the selector switch 14 from the contact position shown in FIG. 1 to the other contact in the opposite direction, and when the fifth switch 18S ₅ is turned on, In conjunction with the second switch 18
S ₂ is turned ON, the contactor coil 18b and the clutch coil 1
8a is excited, the contactor 5 and the electromagnetic clutch 17 are activated, and electric power is supplied to the compressor 16 from the commercial power supply 6. Here, the temperature control of the freezer is performed by opening / closing the electromagnetic clutch 17 by turning on / off the second switch 18S ₂ according to a command from the control circuit 19.

Next, the operation of the second embodiment will be described. What is shown in this embodiment is the same as that shown in the first embodiment.
Since 20 is added to reduce the output frequency of the controller 13 when the output voltage value of the AC generator 12 becomes equal to or lower than a predetermined value, only this point will be described.

When the AC motor 15 is operated by the power generation of the AC generator 12, the rotation speed of the vehicle engine 1 decreases, and the output voltage value of the AC generator 12 is equal to or lower than a predetermined value (the automatic voltage regulator is excited to the maximum). When the frequency becomes less than the voltage value), the frequency control device 20 detects this and sends a command to the controller 13 to decrease the output frequency, and the frequency of the AC voltage output from the controller 13 decreases.

Further, in this second embodiment, the controller 13 is controlled by detecting the output voltage value of the AC generator 12 by the frequency control device 20, but the controller is detected by detecting the rotation speed of the AC generator 12. 13 may be controlled.

Of course, the present invention can be applied not only to the freezer but also to the heat storage.

[Effects of the Invention] As described above, the present invention has the following effects.

In the vehicle-mounted freezer control device according to claim 1, the rotational force of the vehicle engine is once converted into AC power, and the AC voltage is used to operate the AC motor that is operated by the commercial power source when the vehicle is stopped. Therefore, one cooling compressor is used. It should be provided,
The structure is simple, the cost is low, and the frequency of the AC voltage is changed by the controller.
The cooling capacity can be controlled without being restricted by the rotation speed of the vehicle engine, and there is an advantage that the cooling capacity does not decrease even when the engine is rotating at a low speed such as when the vehicle is idling.

According to the on-vehicle freezer control device of the present invention, the frequency of the output voltage of the controller is changed based on the temperature difference between the freezer temperature and an arbitrary set temperature. It has an advantage that accurate control can be performed.

If the switch of the controller is turned on several seconds after the switch of the controller is turned on by the control command from the control circuit, there is an advantage that the startup of the AC motor becomes smooth.

In the vehicle-mounted freezer control device according to claims 3 and 4, the output voltage value or the rotation speed of the AC generator is detected, and when the output voltage or the rotation speed of this AC generator becomes equal to or lower than a predetermined value, the output of the controller is output. Since the frequency is reduced, even if the induction motor is used, even if the AC voltage of the AC generator drops too much, the input current to the induction motor does not become an overcurrent and the induction motor can be operated. It has the advantage of never disappearing.

[Brief description of drawings]

1 is a wiring diagram showing a first embodiment of the present invention, FIG. 2 is a wiring diagram showing a second embodiment of the present invention, and FIG. 3 is a wiring diagram showing a conventional example. 1 …… Vehicle engine, 6 …… Commercial power supply 7 …… Cooler 12 …… AC generator 13 …… Controller 15 …… Motor 16 …… Compressor 18 …… Relay sequence circuit 18S ₁ …… First switch (controller) Switch) 18S ₃ ...... Third switch (compressor switch) 19 ...... Control circuit 20 ...... Frequency controller

Claims (4)

[Claims] 1. An alternator connected to a vehicle engine,
A controller configured by an automatic voltage regulator and an inverter that inputs the output voltage of this AC generator to output an AC voltage of a desired frequency, and an AC voltage output from the controller when the vehicle engine is in operation, When the vehicle engine is stopped, an AC motor that operates by an AC voltage from a commercial power source outside the vehicle, a compressor that is directly connected to a cooler mounted on the vehicle that operates by the rotation of this AC motor, and after the controller is turned ON, An in-vehicle freezer control device, comprising: a control circuit for increasing each value of the AC voltage output from the controller and its frequency to a predetermined value over a predetermined time. 2. The on-vehicle freezer control device according to claim 1, wherein the frequency of the AC voltage output from the controller is changed based on the temperature difference between the freezer temperature and an arbitrary set temperature. 3. The on-vehicle freezer control device according to claim 1, wherein the output voltage value of the AC generator is detected, and the frequency of the AC voltage output from the controller is changed according to the output voltage value. . 4. The on-vehicle freezer control device according to claim 1, wherein the number of revolutions of the AC generator is detected, and the frequency of the AC voltage output from the controller is changed according to the number of revolutions.