JP3327756B2 - Engine driven air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a compressor driven by an engine.

[0002]

2. Description of the Related Art A system diagram of a conventional air conditioner of this type is shown in FIG.
Is shown in During the cooling operation, when the compressor 2 is driven by the water-cooled engine 1, the gas refrigerant discharged from the compressor 2 enters the outdoor heat exchanger 4 through the four-way valve 3 as shown by the solid line arrow. The heat is released to the outside air sent by the outdoor fan 7 to condense and liquefy.

The liquid refrigerant adiabatically expands in the process of flowing through the throttle mechanism 5 and then enters the indoor heat exchanger 6 where it evaporates and vaporizes by cooling the indoor air sent by the indoor fan 8. Thereafter, the gas refrigerant returns to the compressor 2 via the four-way valve 3.

During the heating operation, the four-way valve 2 is switched in the opposite direction, and the refrigerant discharged from the compressor 2 receives the four-way valve 3, the indoor heat exchanger 6, the throttle mechanism 5, the outdoor After passing through the heat exchanger 4 and the four-way valve 3 in this order, the compressor 2
Return to

[0005] The cooling water heated by cooling the engine 1 enters the radiator 9 and radiates heat to the outside air blown by the outdoor fan 7 to lower the temperature. Return to 1.

The number of revolutions of the engine 1 is determined according to the air-conditioning load, and is set in a preset use range (for example, 700 to 2400).
The engine 1 was stopped when the rotation speed reached the upper limit rotation speed (for example, 2600 rpm) exceeding the minimum rotation speed (for example, 600 rpm).

[0007]

In the above conventional air conditioner, a predetermined deviation (200 rpm) is set between the maximum allowable rotation speed (2400 rpm) and the upper limit rotation speed (2600 rpm) of the engine 1. However, if this deviation is set to be small, the engine speed may overshoot during the control of the rotation speed of the engine 1 in accordance with the air-conditioning load, thereby reaching the upper limit rotation speed and stopping. The engine speed rises above the upper limit speed and the engine 1
And the compressor 2 may be damaged.

Further, even when the rotation speed of the engine 1 is reduced beyond the range of use, the engine 1 is stopped due to overshoot of the engine rotation speed, or the engine rotation speed is reduced below the lower limit rotation speed of 600 rpm. The compressor 2 may be seized or abnormally worn due to poor lubrication.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its gist is to provide a compressor driven by an engine, an outdoor heat exchanger, a throttle mechanism, An engine-driven air conditioner that includes a refrigeration cycle including an indoor heat exchanger and controls the number of revolutions of the engine according to the air-conditioning load. An engine-driven air conditioner, wherein a rotation restricting means for stopping the engine after a lapse of a time corresponding to the engine speed is provided when the rotation speed is out of the range of use. .

Another feature is that the rotation restricting means sets a plurality of abnormal rotational speed ranges in a high rotational speed range outside a use range. The lower the rotational speed, the longer the operation time, and the higher the rotational speed, the longer the operation time. Another object of the present invention is to provide a high-rotational-range regulating means which is set to be short.

Still another feature is that the rotation restricting means has a low rotation range restricting means in which the operation time is set shorter as the number of rotations becomes lower in a low rotation range outside the range of use.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIGS. An engine control device 20 for controlling the engine 1 is provided. The engine control device 20 includes an air conditioning load calculation unit 21, a rotation speed determination unit 22, and a rotation restriction unit.
23. The rotation restricting means 23 includes a high rotational speed restricting means 24 and its setting means 25, and a low rotational speed restricting means 26 and its setting means 27.

The room temperature detected by the room temperature sensor 28 and the set temperature set by the room temperature setting unit 29 are input to the air-conditioning load calculating means 21, where the air-conditioning load is calculated based on these. The calculated air conditioning load is used as the rotation speed determining means 22.
The rotation speed of the engine 1 is determined based on the air-conditioning load. If the determined rotation speed is within a preset use range (for example, 700 to 2400 rpm), it passes through the rotation control means 23 and is output to the engine 1, and the engine 1 rotates at a rotation speed corresponding to the air conditioning load. I do.

The rotational speed of the engine 1 is detected by a rotational speed detecting means 30, and the detected value is inputted to a high rotational speed regulating means 24 and a low rotational speed regulating means 26.

When the number of revolutions of the engine 1 is equal to the upper limit (240
When the rotation speed exceeds 0 rpm), the high revolution range restricting means 24 decides to stop the engine 1 after a lapse of a predetermined time based on data set in the setting means 25 in advance.

As shown in FIG. 2, a plurality of (three in the figure) abnormal rotational speed ranges A, B, and C are set in the high rotational speed range outside the use range in the setting means 25. The operation time is set longer for a lower abnormal speed range and shorter for a higher abnormal speed range.

Thus, even if the engine speed determined according to the air-conditioning load exceeds the upper limit of the use range of 2400 rpm, the engine 1 does not stop for 10 seconds at 2500 rpm or less. Therefore, if the cause of the overshoot is an overshoot, it falls within the range of use in these 10 seconds, so that troubles caused by stopping the engine 1 can be avoided.

However, when the engine speed increases to 2600 rpm or more, the engine 1 stops after one second, so that the compressor 1 can be prevented from being damaged due to the continuation of the high-speed rotation of the engine 1.

On the other hand, when the rotation speed of the engine 1 falls below the lower limit of the operating range (700 rpm), the low rotation range restricting means 26
Determines to stop the engine 1 after a lapse of time determined based on the data set in the setting means 27.

As shown in FIG. 3, the operating time of the setting means 27 is set to be shorter as the rotational speed becomes lower in a low rotational speed range outside the range of use. Thus, when the engine speed determined according to the air-conditioning load falls below the lower limit of the use range (700 rpm), if the engine speed is 600 rpm, the engine 1
Stops, but the engine stops immediately if the speed drops to 500 rpm, so that seizure or abnormal wear due to poor lubrication of the compressor 2 can be prevented.

[0021]

According to the present invention, when the engine speed is out of the preset use range, the engine is stopped after a lapse of a time corresponding to the engine speed. It is possible to avoid stopping the engine when the rotation speed exceeds the range of use due to overshoot.

A plurality of abnormal rotational speed ranges are set in a high rotational speed range outside the range of use, and a high rotational speed regulating means is provided in which the operating time is set longer as the rotational speed is lower and the operating time is set shorter as the rotational speed is higher. Thus, it is possible to prevent the engine and the compressor from being damaged when the engine speed is abnormally increased.

By providing a low-rotational-range regulating means in which the operation time is set to be shorter as the rotational speed becomes lower in a low-rotational region outside the range of use, the seizure of the compressor or abnormal operation when the engine rotational speed is abnormally decreased can be provided. Wear can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a table showing a relationship between an engine speed and an operation time in a high rotation range according to the embodiment.

FIG. 3 is a diagram illustrating a relationship between an engine speed and an operation time in a low rotation speed range of the embodiment.

FIG. 4 is a system diagram of a conventional engine-driven air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Compressor 4 Outdoor heat exchanger 5 Throttle mechanism 6 Indoor heat exchanger 20 Engine control device 30 Revolution detection means 23 Revolution control means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Michio Yoneda, Nagoya Research Laboratories, Nagoya Research Lab., Nagoya Research Laboratories, Nagoya-shi 3-chome No. 1 Mitsubishi Heavy Industries, Ltd. Aircon Works (56) References JP-A-3-189339 (JP, A) JP-A-58-214628 (JP, A) JP-A-63-90637 (JP, A) JP-A-58-23238 (JP, A) JP-A-62-150042 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 29/04 F02D 17/04 F02D 45 / 00 345

Claims (3)

(57) [Claims] 1. An engine-driven air system comprising a refrigeration cycle including a compressor driven by an engine, an outdoor heat exchanger, a throttle mechanism, and an indoor heat exchanger, wherein the engine speed is controlled according to an air conditioning load. In the harmony device, the engine speed detecting means is provided, and when the engine speed is in a speed range outside a preset use range, the engine is operated after a lapse of a time corresponding to the engine speed. An engine-driven air conditioner comprising a rotation restricting means for stopping. 2. The rotation restricting means sets a plurality of abnormal rotational speed ranges in a high rotational speed range outside a use range. The lower the rotational speed, the longer the operation time, and the higher the rotational speed, the shorter the operation time. The engine-driven air conditioner according to claim 1, further comprising a rotation range restricting means. 3. The engine according to claim 1, wherein said rotation restricting means has a low rotation range restricting means in which the operation time is set shorter as the number of revolutions becomes lower in a low rotation range outside a use range. Driven air conditioner.