JPH03186427A - Displacement control device for engine-driven compressor - Google Patents

Abstract

PURPOSE:To suppress speed fluctuation of an engine, which follows volume fluctuation of a compressor so as to attempt stable operation by delaying control speed of the volume of the compressor, driven by the engine, during its idle operation. CONSTITUTION:The volume of a variable displacement compressor COM, which is driven by an engine E/G of a vehicle to compress and deliver a refrigerant, is controlled by a volume control means M1 in accordance with a room-cooling load or a frost condition of an evaporator. In such a device as in the above, idle operation of the engine E/G is detected by an idle operation detecting means M2. When the idle operation of the engine E/G is detected, a volume control speed is changed by a control speed changing means M3 in such a manner that the volume control speed of the compressor COM by the volume control means M1 is delayed. In this way, speed fluctuation of the engine E/G following volume fluctuation of the compressor COM, during its idle operation, is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a capacity control device for an engine-driven compressor that controls the capacity of a variable capacity compressor driven by an engine.

[Prior Art] Conventionally, vehicle air conditioners have used a variable capacity compressor to compress refrigerant, and the frost condition is determined by the cooling load that changes depending on the room temperature or the air temperature immediately after the evaporator. There are some that control the capacity of the compressor according to the

In addition, with this type of device, when the vehicle accelerates or when driving on a hill,
When the engine load suddenly increases, the compressor capacity is quickly reduced to reduce the engine load caused by the compressor, and vice versa (when the engine is decelerating, the compressor capacity is quickly increased to reduce engine deceleration.) In order to enable the compressor to be driven efficiently by energy, it has been considered to control the compressor capacity faster than usual when the vehicle is accelerating or decelerating (for example, Japanese Patent Publication No. 62-975). .

[Problems to be Solved by the Invention] However, in the past, as described above, the engine can be operated smoothly by controlling the capacity control speed of the compressor during transient engine operation such as during acceleration or deceleration. Although this has been considered, when the cooling load changes and the compressor capacity is changed during steady engine operation (because it was done at a predetermined control speed that was set in advance), Particularly during idling operation when the engine generates little torque (above), there was a problem in which the engine speed fluctuated rapidly due to changes in the compressor capacity.

The present invention was made in view of these problems, and an object of the present invention is to provide a capacity control device for an engine-driven compressor that can suppress fluctuations in engine rotation caused by changes in the capacity of the compressor during idling operation.

[Means for Solving the Problems] That is, the present invention has been made to achieve the above object (as illustrated in FIG. 1, a variable capacity compressor that is driven by a vehicle engine E/G, compresses and discharges refrigerant) In a capacity control device for an engine-driven compressor, the capacity control device for an engine-driven compressor includes a capacity control means Ml that controls the capacity of the type compressor COM according to the cooling load or the frost state of the evaporator. a detection means M2; a control speed changing means M3 for slowing down the capacity control speed of the compressor COM by the capacity control means M when the idle operation of the engine E/G is detected by the idle operation detection means M2; The gist of this paper is a capacity control device for an engine-driven compressor, which is characterized by being equipped with a.

[Operation] In the capacity control device for an engine-driven compressor of the present invention configured as described above, the capacity control means M1 controls the capacity of the variable capacity compressor COM according to the cooling load or the frost state of the evaporator. At the same time, when idle operation of the engine E/G is detected by the idle operation detection means M2, the control speed changing means M3 slows down the capacity control speed of the compressor COM by the capacity control means M1.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

First, FIG. 2 is a schematic configuration diagram showing the configuration of an engine 10 and an air conditioner 30 mounted on a vehicle.

As shown in the figure, the engine 101i is composed of an engine main body 11, an intake pipe 12 and an exhaust pipe 13 connected to the engine main body 11.

The intake pipe 12 is operated by a driver, and the engine body 1 is connected to the intake pipe 12.
A throttle valve 14 is provided to adjust the intake air amount to 1.
The throttle valve 14 is provided with an idle switch 15 that detects the fully closed state of the throttle valve 14 and turns on.

In addition, a bypass passage 16 is provided in the intake pipe 12 (upper side) to bypass the throttle valve 14;
6 (Table) By adjusting the passage area of the bypass passage 16, the bypass passage 16 can be closed when the throttle valve 14 is fully closed.
A well-known idle speed control pulp (ISCV) 17 is provided to regulate the amount of air passing through.

Note that this l5CV17 adjusts the engine rotational speed NE during idling operation in which the throttle valve 14 is fully open.

Next, a pressure sensor 18 is provided in the intake pipe 12 to detect internal pressure (intake pipe pressure) PM downstream of the throttle valve 14.
Furthermore, a fuel injection valve 19 is provided at a branched portion of the intake pipe 12 corresponding to each cylinder.

On the other hand, the engine body 11 is provided with a spark plug 20 for igniting the air-fuel mixture taken into the combustion chamber via the upper intake pipe 12, and a water temperature sensor 21 for detecting the temperature of cooling water for cooling the engine body 11. A rotation angle sensor 23 is provided on the crankshaft 22 of the engine body 11 to detect the rotation angle of the crankshaft 22.

Next, the air conditioner 30 (includes a variable capacity compressor (A/C combo) 31 that can continuously change the stroke volume of the air conditioner 30). It is connected to the crankshaft 22 of the engine 10, and is driven by the driving force of the engine 10.The refrigerant in a gaseous state is compressed by driving the A/C combination 31.

The A/C combination 31 is connected to a condenser 34 via a high-pressure side refrigerant pipe 33 17, and in the condenser 34, the refrigerant discharged from the A/C combination 31 radiates heat and liquefies. Further, the condenser 34 is connected to a receiver 35, and the liquefied refrigerant is temporarily stored in the receiver 35. Furthermore, this receiver 351 is connected to an expansion valve 39 whose opening degree changes according to a temperature-sensitive cylinder 38 provided in a low-pressure side refrigerant pipe 37 on the downstream side of the evaporator 36, which will be described later. The refrigerant is expanded by an amount corresponding to the opening degree of the expansion valve 39.

Next, in the evaporator 36 connected to the expansion valve 39, the expanded refrigerant is vaporized. During this vaporization, the refrigerant takes away heat from the surroundings, so the air around the evaporator 36 is cooled. Further, an outlet temperature sensor 40 is provided at the outlet through which air cooled by the evaporator 36 is blown out into the vehicle interior.

Then, the refrigerant vaporized in the evaporator 36 is guided to the A/C combination 31 via the low-pressure side refrigerant pipe 37. Furthermore, A/C
to the comb 31 (discharge amount of refrigerant, i.e. A/C comb 31)
A capacitance sensor 41 is provided to detect the variable capacity of the refrigerant, and each of the refrigerant pipes 33 and 37 on the high-pressure side and the low-pressure side is provided with a high-pressure pressure sensor 42 and a low-pressure pressure sensor 43, respectively, to detect the pressure of the refrigerant.

The engine 10 and the air conditioner 30 are equipped with an electronic control unit (
The drive is controlled by an ECU (ECU) 50. ECtJ501J
,, the above-mentioned idle switch 15. Pressure sensor 18. Water temperature sensor 211 Rotation angle sensor 23° Outlet temperature sensor 40.
Capacitive sensor 41. High pressure pressure sensor 42. Low pressure sensor 43. The engine 10 and the air conditioner 30 are controlled in response to signals from the air conditioner switch 45, etc., which are closed by the driver's command to operate the air conditioner 30. It is composed mainly of computers.

As is well known, the control of the air conditioner 30 by the ECU 3O is as follows.
High pressure pressure sensor 42. This control is performed based on various sensor signals from the low-pressure sensor 43, etc., and below, among these controls, the main control related to the present invention, the A/C combination 3
The capacity control of No. 1 will be explained along the flowchart shown in FIG.

The capacity control LLEC 50 is a process that is repeatedly executed together with other control processes such as engine control, and when the process is started, it is first determined in step 100 whether or not the air conditioner switch 715 is in the on state. If the air conditioner switch 45 is in the off state, the process moves to step 110, and the electromagnetic clutch 32 disconnects the A/C combination 31 from the crankshaft 22 of the engine 10, thereby turning off the A/(,) pump 31. Then, the process is temporarily terminated.

On the other hand, if it is determined in step 100 that the air conditioner switch 715 is in the on state, it is determined in step 120 (proceed to this step, the idle switch) 5 is in the on state. is off,
If the engine 10 is not idle
Proceeding to step 130, the air outlet temperature detected by the air outlet temperature sensor, the vehicle room temperature, the amount of solar radiation, and the outside air temperature determined by other sensors.

Alternatively, based on the target room temperature set by the driver, it is determined whether or not to increase the cooling capacity in order to control the vehicle room temperature to the target room temperature.

If it is determined in step 130 that the cooling capacity should be increased, the process moves to step 140[,T, where the duty ratio of the capacity control signal output to the A/C combination 31 is set to 2 in order to increase the capacity of the A/C combination 31. %, the capacity control is executed and the 1-1 process is temporarily ended. Conversely, if it is determined in step 130 that the cooling capacity should not be increased, the process proceeds to step 150, in which the duty ratio of the capacity control signal output to the A/C combination 31 is determined in order to reduce the capacity of the A/C combination 31. Capacity control is executed by decreasing the amount by 2% 2, and the process is temporarily terminated.

On the other hand, if it is determined in step 120 that the idle switch 15 is on and the engine 10 is in idle operation (upper step 160, similarly to step 130 above, the cooling capacity is increased). If it is determined in step 160 that the cooling capacity should be increased, the process moves to step 170 and the A/C
In order to increase the capacity of the comb 31, the A/C comb 31
Capacity control is executed by increasing the duty ratio of the capacity control signal output by 1%, and the process is temporarily terminated.

On the other hand, if it is determined in step 160 that the cooling capacity is not increased, the process moves to step 180, and the duty ratio of the capacity control signal output to the A/C combination 31 is set to decrease the capacity of the A/C combination 31. Capacity control is executed by decreasing the amount by 1%, and the process is temporarily terminated.

As explained above, in this embodiment, when the engine 10 is in non-idling operation, the duty ratio of the capacity control signal is set to 2.
By changing the duty ratio of the capacity control signal by 1%, the capacity of the A/C combination unit 3 can be increased or decreased by changing the duty ratio of the capacity control signal by 1% when the engine 10 is idling.
The capacity of the kelp 31 is increased or decreased. For this reason, the air conditioner 10 of this embodiment provides 1'! During idling operation, the rate of increase/decrease in the capacity of the A/C combination 31 is made slower than during non-idling operation, thereby preventing large rotational fluctuations in the engine 10.

In other words, as shown in FIG. 4, during non-idling operation of the engine 10 when the idle switch 15 is in the OFF state, the engine load in the vehicle drive system is large, so the A/C combination 3
A/C combination unit 3 is designed so that the amount of refrigerant discharged from unit 1 can quickly follow changes in external cooling load.
Even if the control speed of the capacity of the engine 10 is increased, large rotational fluctuations will not occur in the engine 10 due to changes in the capacity of the A/C combination 31. Since the engine load on the drive system is small, the A/C
If the control speed of the kelp 31 capacity is left unchanged,
A large rotational fluctuation occurs in the engine 10, and in some cases, an engine stall occurs. Therefore, in this embodiment, as shown by the solid line in the figure, the rate of increase/decrease in the duty ratio of the capacity control signal during idling operation is made smaller than that during non-idling operation, and the control speed of the capacity of the A/C combination 31 is slowed down. (reducing the slope of capacitance change shown in the figure)
This prevents rotational fluctuations of the engine 10 that would occur if the external cooling load changes during idling operation.

Here, in the above embodiment, the idle operation of the engine 10 is detected by the idle switch 15, and during idle operation (by simply making the change rate of the duty ratio of the control signal of the A/C combination 31 smaller than during non-idling operation). , the control speed of the capacity of the A/C combo 31 is slowed down, but even if the idle switch 15 is in the ON state, the engine 10 may be affected by changes in the capacity of the A/C combo 31 due to differences in engine load. Since the rotational fluctuations are different, while suppressing the rotational fluctuations of the engine 10, the A/
In order to be able to change the capacity of the C comb 31 more quickly, it is desirable to change the capacity control speed according to the load state of the engine 10 during idling operation.

In other words, for example, in a vehicle equipped with an automatic transmission (above), even if the idle switch 15 is on, the engine load will vary depending on whether the gear range is in the neutral range (N range) or the drive range (D range). On the other hand, when the gear shift range is in the N range, the engine load is smaller and the rotational fluctuation of the engine 10 increases with respect to the change in the capacity of the A/C combination 31. It is desirable to perform the capacity control according to the procedure shown in FIG. 5, for example.

The capacity control shown in FIG. 5 will be explained below.

As shown in the figure, with this capacity control E, first step 20
0, it is determined whether or not the air conditioner switch 45 is in the on state, and if the air conditioner switch 45 is in the off state, the process moves to step 210 and the A/C combo 31 is turned off; otherwise, the process proceeds to step 220. It is determined whether the idle switch 15 is in the on state. If the idle switch 15 is in the OFF state and the engine 10 is not in idle operation, a change value ΔD (binary value 3) of the duty ratio of the capacity control signal is set in step 230.

On the other hand, when the idle switch] 5 is on, the engine 10
is running at idle, step 240
Then, it is determined whether the shift range of the automatic transmission (AT) is the N range.

If the shift range is N range, step 250
At step 260, the duty ratio change value ΔD of the capacity control signal is set to 1, and if the shift range is not N+ or N+, then at step 260 the duty ratio change value ΔD of the capacity control signal is set to 1.
Set D to the value 2.

After the duty-day ratio change value △D of the capacity control signal is set in this way, the process moves to step 270 +, :m, and it is determined whether the temperature blown out from the air conditioner is lower than the target value or not. ~, if the outlet temperature is lower than the target value, step 2
Step 80 [-2] The capacity control is performed by decreasing the duty ratio of the capacity control by the change value △[) set above, and if the number of blowouts is equal to the target value of 1, the process proceeds to step 290. Then, it is determined whether the outlet temperature exceeds the target value. If the outlet temperature exceeds the target value (upper step 300), capacity control is performed by increasing the duty ratio of the capacity control signal by the change value ΔD set above. Otherwise (i.e., if the outlet temperature is at the target value), step 3
10, the capacity control is executed without changing the duty ratio of the capacity control signal.

As described above, in the capacity control shown in FIG. If so, set the duty ratio change value ΔD (7 minimum value 1, and if the shift range is D range, set the duty ratio change value ΔD when the idle switch 15 is off (
In other words, the intermediate value 2 is set to be smaller than that during non-idling operation. During idle operation of the engine 10, the smaller the engine load, the smaller the capacity control speed of the A/C compressor 31 can be made according to the engine load, suppressing rotational fluctuations of the engine 10.
It becomes possible to effectively control the capacity.

Next, in the above embodiment, the idle operation of the bone engine 10 is detected using the idle switch 15 which is turned on when the throttle valve is fully opened. air volume,
(1) It may be detected from the throttle opening, etc.

In addition, in this case, the engine load is calculated from each of these values (::shi, the capacity control speed J
The main color may be changed.

In addition, in the above embodiment, an explanation will be given of a device that controls the capacity of the A/C compressor 31 by controlling the duty ratio of the 4-mi capacity control signal. The target capacity of the A/C compressor 31 is set based on the deviation between the temperature and the target value, and the A/C compressor 31 is controlled so that the capacity of the A/C compressor 31 becomes this target capacity.
Capacity control by ID (proportional/integral/derivative) control6"7
In a device that performs this, the color of the control speed may be changed by changing the control gain for calculating the target capacity of the A/C converter 31.

Furthermore, in the above embodiment, when the engine 10 is in idle operation; secondly, the capacity increasing speed and decreasing speed of the A/C combination 31 are both slowed down by l:X;
Even if the control speed is reduced only when increasing the capacity of the engine 10, fluctuations in the rotation of the engine 10 can be suppressed. ``-1 engines can be reliably prevented.

In addition, in the above embodiment, when the engine 10 is running at idle, the capacity control speed is always made slower than at non-idling operation.
It is also possible to monitor the operating condition in which the capacity h<sudden change of the C comb 31, and to slow down the capacity control speed by one hour when the second condition is detected.

In other words, for example, E7 monitors changes in set temperature, sudden changes in cabin temperature, sudden changes in engine speed, etc., and slows down the capacity control speed for a certain period of time when these conditions are detected.
However, sudden changes in engine speed can be suppressed.

[Effects of the Invention 1] As detailed above, according to the capacity control device for an engine-driven compressor of the present invention, the capacity control speed of the compressor is slowed down during engine idling. This prevents large fluctuations in engine speed due to changes in capacity, allowing the engine to operate stably.

[Brief explanation of drawings]

Fig. 1 is a block diagram illustrating the configuration of the present invention, Fig. 2 is a schematic configuration diagram showing the configuration of the engine and air conditioner installed in the vehicle of the embodiment, and Fig. 3 shows the capacity control executed by the ECU. FIG. 4 is a time chart illustrating the operation of the capacity control, and FIG. 5 is a flow chart illustrating the capacity control in a vehicle equipped with an automatic transmission. E/G, 10...Engine COM, 31...Variable displacement compressor M1...
Capacity control means M2...Vibration detection means M3...Capacity limiting means 30...Air conditioner 50...Electronic control unit 15...Idle switch 45...Air conditioner switch) - (ECU)

Claims (1)

[Scope of Claims] An engine drive comprising: capacity control means for controlling the capacity of a variable capacity compressor that is driven by a vehicle engine and compresses and discharges refrigerant in accordance with a cooling load or a frost state of an evaporator. A capacity control device for a type compressor includes an idle operation detection means for detecting idle operation of an engine, and when the idle operation detection means detects idle operation of the engine, a capacity control speed of the compressor by the capacity control means is controlled. A capacity control device for an engine-driven compressor, characterized by comprising: a control speed changing means for slowing down the control speed;