JPH03186426A - Displacement control device for engine-driven compressor - Google Patents

Abstract

PURPOSE:To suitably decrease a load of an engine so as to suppress its vibration by limiting the displacement of a compressor, driven by the engine, in such a manner that the larger is the engine vibration the smaller the displacement is decreased, in a low speed region of the engine. 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, engine vibration is detected by a vibration detecting means M2 directly or indirectly being based on an operational condition of the engine E/G. In a low speed region of the engine E/G, the volume of the compressor COM is limited by a volume limiting means M3, in a manner wherein the larger is the engine vibration increased the smaller the volume of the compressor COM is decreased, in accordance with the detected engine vibration. Thus, by suitably decreasing a load of the engine, its vibration is well suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] 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 two.

[Prior Art] Traditionally, vehicle air conditioners have used a variable capacity type compressor to compress refrigerant color. There is a type of compressor that controls the capacity of the compressor depending on the frost condition.

In this type of equipment, the compressor is constantly driven, so compared to equipment that performs on/off control such as stopping the compressor and starting it again, the driving force of the compressor can be reduced, and the refrigerant However, if the capacity of the compressor is controlled only by the cooling load, the load on the engine that drives the compressor becomes too large and the engine cannot operate stably. It may disappear.

Therefore, conventionally, as described in, for example, Japanese Patent Application Laid-Open No. 63-235121, it has been considered to detect engine knocking using a knocking sensor, and to set the capacity of the compressor to the minimum capacity when knocking is detected.

[Problem to be solved by the invention] By detecting knocking in this way and reducing the compressor capacity to the minimum capacity (e) By reducing the engine load when knocking occurs, it is possible to suppress knocking. However, although these measures can suppress engine knocking, they cannot suppress vehicle vibrations that occur when the engine is running at low speeds, especially during idling.

In other words, if the capacity of the compressor increases when the engine is running at low speeds, such as during engine idling, the engine load becomes excessive and the engine vibrates, and the vibrations are transmitted through the engine mount system. This is transmitted to the vehicle body and causes discomfort to the occupants, but since the knocking sensor detects abnormal combustion in the engine,
Engine vibrations cannot be detected, and therefore conventional methods cannot suppress vehicle vibrations that occur when the engine rotates at low speeds.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a capacity control device for an engine-driven compressor that can satisfactorily suppress vehicle vibrations that occur when the engine rotates at low speeds.

[Means for Solving the Problems] That is, the present invention has been made to achieve the above object (as illustrated in FIG. In a capacity control device for an engine-driven compressor, the capacity control device includes a capacity control means Ml that controls the capacity of a type compressor COM according to the cooling load or the frost state of the evaporator. The vibration detection means M2 indirectly detects the capacity of the compressor COM controlled by the capacity control means M1 in a predetermined low rotation range of the engine E/G. The gist of the present invention is to provide a capacity control device for an engine-driven compressor, which is characterized in that it is provided with a capacity limiting means M3 that limits the engine vibration so that the larger the engine vibration, the smaller the engine vibration.

[Function] In the capacity control device for an engine-driven compressor of the present invention configured as described above (, t, capacity control means M
1 controls the capacity of the variable capacity compressor COM according to the cooling load or the frost state of the evaporator, and when the engine E/G is in a predetermined low rotation range (as shown in FIG. The compressor C is controlled by the capacity control means M1 so that the larger the engine vibration is, the smaller the engine vibration is, depending on the engine vibration detected by the means M2.
Limit the capacity of OM.

For this reason, if the engine vibration becomes large when the engine E/G rotates at low speeds, use a variable capacity compressor E/G.
As a result, the engine load is reduced, and engine vibration is suppressed.

[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 O and an air conditioner 30 mounted on a vehicle.

As shown in the figure, an engine 101-& engine body 11, an intake pipe 12 and an exhaust pipe 13 connected to the engine body 11,
It consists of

The intake pipe 12 is provided with a throttle valve 14 that is operated by the driver and adjusts the amount of intake air into the engine body 11.The throttle valve 14 has an idle switch 15 that is turned on when the throttle valve 14 is detected to be fully open. It is provided.

In addition, a bypass passage 16 is provided in the intake pipe 12 to bypass the throttle valve 14.
By adjusting the passage area of the bypass passage 16, the bypass passage 16 is
A well-known idle speed control pulp (IscV) 17 is provided to regulate the amount of air passing through.

Note that this ISC]7 adjusts the engine speed NE during idling operation when the throttle valve 14 is fully closed.

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.
Further, 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 through the 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 for detecting the rotation angle of the crankshaft 22 is provided on the crankshaft 22 of the engine body 11.

Next, the air conditioner 30 includes a variable capacity compressor (A/C compressor) 31 that can continuously change its stroke volume. The A/C combination 31 is connected to the crankshaft 22 of the engine 10 via an electromagnetic clutch 32, and is driven by the driving force of the engine O.

Note that the refrigerant in a gaseous state is compressed by driving the A/C combination unit 3.

The A/C combination 31 is connected to a condenser 34 via a high pressure side refrigerant pipe 33, and in the condenser 34,
The refrigerant discharged from the A/C combination 31 radiates heat and liquefies. The condenser 34 is also connected to a receiver 35, in which the refrigerant (in liquid form) is temporarily stored.

Furthermore, an expansion valve 39 whose opening degree changes according to a temperature-sensitive tube 38 provided in a low-pressure side refrigerant pipe 37 downstream of an evaporator 36, which will be described later, is connected to this receiver 35. The refrigerant is expanded by an amount corresponding to the opening degree of the expansion valve 39.

Next, the refrigerant that expanded upward is vaporized in the evaporator 36 connected to the three expansion valves. During this vaporization, the refrigerant takes away the heat from the surroundings, so the air surrounding the evaporator 36 is cooled. A blowout temperature sensor 40 is provided at the outlet through which the cooled air 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
The kelp 31 is provided with a capacity sensor 4 for detecting the variable capacity of the A/C pump 31, which measures the discharge of refrigerant.
Further, 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, for detecting the pressure of the refrigerant.

The engine 10 and the air conditioner 30 are driven and controlled by an electronic control unit (ECU) 50. ECU3O is
The above-mentioned idle switch 15. Pressure sensor 18. Water temperature sensor 219 Rotation angle sensor 23° Outlet temperature sensor 40. Capacitive sensor 41. High pressure pressure sensor 42. Low pressure sensor 43
．． An air conditioner switch 45 that is closed when the driver operates the air conditioner 30. It is for controlling the engine 10 and the air conditioner 30 according to signals from the vehicle speed sensor 46 and the like that detect the vehicle speed SPE, and includes a CPU, ROM,
It is mainly configured with a well-known digital computer such as RAM.

Control of the air conditioner 30 by the ECU 3O As is well known, the high pressure sensor 42. This control is performed based on various sensor signals from the low-pressure pressure sensor 43, etc., and the following are the following:
The present invention (two main controls involved, A/C combination 3)
The capacity control of No. 1 will be explained along the flowchart shown in FIG.

Capacity control (above) In the ECU 3O, when the air conditioner switch 45 is in the ON state, this is a process that is repeatedly executed together with other control processes such as engine control. 23. Based on the detection signals from the capacity sensor 41, low pressure sensor 43. and vehicle speed sensor 46, the intake pipe pressure P
M, engine rotation speed NE, capacity Vc of A/C combination 31, refrigerant pressure in low-pressure side refrigerant pipe 37 (low-pressure refrigerant pressure) Ps, and vehicle speed SPE e are detected, and step 11
Transition to 0.

In step 110, the low-pressure refrigerant pressure Ps detected in step 100 and the target pressure Pso, which is preset in another control process (not shown) in order to obtain the cooling capacity for controlling the vehicle interior temperature to the target temperature, are adjusted in magnitude. Then, if the low-pressure refrigerant pressure Ps is larger than the target pressure Pso, the process moves to step 120 and the capacity i detected in step 100 is compared.
A value obtained by adding a predetermined value α to Vc is calculated as the target capacity VCO of the A/C combination unit 31, and if not, step 130
The target capacity Vco of the A/C combination unit 31 is determined by subtracting the predetermined value α from the capacity VC detected in step 100.
Calculated as

In this way, the target capacity Vc of the A/C combination unit 31.

Once calculated, the process moves to step 140, where the engine 10 idle conditions such as the idle switch 15 being on and the vehicle speed SPE being less than or equal to a predetermined value (for example, 5+n/h) are satisfied. Determine whether or not. If it is determined in step 140 that the idle condition is not satisfied, step 24 described below
0 and it is determined that the idle condition is satisfied, the process moves to the following step 150, and based on the engine speed NE and intake pipe pressure PM detected in step 100, the engine speed is adjusted as shown in FIG. Using map A, engine 1O
The vibration level LV of is predicted.

Here, the vibration level LV is calculated from the engine speed NE and the intake pipe pressure PM (as shown in FIG. , becomes larger.In other words, in this embodiment, the engine load is calculated by the intake pipe pressure PM.
Based on the intake pipe pressure PM and the engine rotational speed NE, the engine vibration LV is estimated using map A shown in FIG. 4, which has been set in advance through experiments.

Next, when the vibration level LV is calculated in step 150, the process moves to step 160, and it is determined whether or not this vibration level LV is equal to or higher than a preset upper limit value LVmax. If the vibration level LV is equal to or higher than the upper limit value LVmax, in step 170, a reduction correction value dVc of the target capacity Vco is calculated by multiplying the vibration level LV by a constant.
Otherwise, in step 180, the correction value dV
Set c to 0. Furthermore, the upper limit value LVma of the vibration level LV
A permissible upper limit value is set for X that does not cause discomfort to vehicle occupants.

Next, in step 190, it is determined whether the weight loss correction value dVc is greater than or equal to a preset upper limit value dVmax. If the weight loss correction value dVc is greater than or equal to the upper limit value dVmax (E
In step 200, the target idle speed NT of the engine 10 is increased by a value obtained by multiplying the reduction correction value dVc by a constant β, and further in step 210, the reduction correction value dVc is set to the upper limit value dVmax.

The process of steps 200 and 210 is a process for preventing the target capacity Vco from being reduced too much by the reduction correction value dVc and the cooling capacity of the air conditioner 30 being reduced. The vibration level LV of the engine 10 is decreased by increasing the idle speed NT, and the reduction correction value dVc is set to the upper limit value dVmax in step 210.The target idle speed increased in step 200 The base value of the number NT is 1. This is a well-known value that is preset in accordance with the cooling water temperature, etc. in another control routine (not shown).

Next, in step 210, the weight loss correction value dVclgo upper limit value d
If Vmax is set or if it is determined in step 190 that the reduction correction value dVc is smaller than the upper limit value dVmax, the process moves to step 220, where the current target idle rotation speed NT and the engine rotation detected in step 100 are determined. l5C drives l5CV17 according to the deviation from the number NE and controls the engine speed NE to the target idle speed NT.
Execute V control processing. And in the following step 230 (
Friend: The target capacity Vco obtained in step 120 or step 130 is corrected for reduction using the reduction correction value dVc.

In this way, the target capacity Vc is determined at step 230.

If the amount is corrected or it is determined in step 140 that the idle condition is not satisfied, then step 24 is performed.
0, and the capacity Vc of the A/C combo 31 is set to the target capacity V.
Then, the well-known capacity control is executed, and the processing of this routine is temporarily terminated.

As explained above, in this embodiment, when the 1-up idle condition is satisfied, the vibration level LV of the engine]0 is predicted from the engine speed NE and the intake pipe pressure PM, and the vibration level LV
is greater than or equal to the preset upper limit LVmax (
Friend: Weight loss correction value dVc calculated according to vibration level LV
The target capacity Vco of the A/C combination unit 3 is corrected to reduce the target capacity Vco using the following. For this reason, if large engine vibrations that cause discomfort to vehicle occupants occur, li A/
By reducing the load torque of the engine 10 caused by the C combination 31, engine vibration can be suppressed.

In addition, in this embodiment, when the reduction correction value dVc of the target capacity Vc exceeds the upper limit value dVmax and the cooling capacity of the air conditioner 30 decreases too much, the reduction correction value dVc is set to the upper limit value dVmax. However, since engine vibration is suppressed by increasing the engine speed NE, engine vibration can be suppressed while ensuring a predetermined cooling capacity.

Here, in the above embodiment, the vibrating bell LV of the engine 10
is predicted based on the engine speed NE and intake pipe pressure PM, etc., but the load torque of the engine 10 is
/C Kombu 3]'s YoiVC.

Alternatively, the larger the refrigerant pressure (high-pressure refrigerant pressure) Pd in the high-pressure side refrigerant pipe 33 detected by the high-pressure pressure sensor 42 becomes, the greater the engine vibration (as shown in FIG. 6(a) or (b)). The larger the capacity Vc is and the lower the engine speed NE is 'fL, or the higher the high-pressure refrigerant pressure Pd is and the lower the engine speed NF, the larger the difference between the capacity Vc and the engine speed NE, or the high-pressure refrigerant pressure Pd and the engine speed. The vibration level may be determined based on NE, and V may be predicted.

In addition, in this case, the engine load other than the A/C combination 31,
That is, the engine load caused by the alternator, power steering, etc. is detected from the operating state, and the A/C combination 31 (
The vibration level LV may be predicted in conjunction with the engine load based on two factors. Furthermore, engine vibrations may be directly detected using a sensor.

Further, in the above embodiment, the engine 1
When the idle condition of 0 is satisfied, the engine 10
The vibration level and Vt of the engine were predicted and the target capacity Veo of the A/C combination unit 31 was reduced and corrected. However, since engine vibration becomes a problem in the low speed range of the engine 10, As shown, engine speed NE
The maximum permissible value of the capacity Vc of the A/C combination 31 is set from the engine rotation speed N and the intake pipe pressure PM when the engine speed is below a predetermined rotation NEO, and the target capacity Ve of the A/C combination 31 is set.
Control may be performed so that o is equal to or less than this maximum allowable value.

Next, in the above embodiment, the vibration level V of the engine 10 was calculated from the engine rotation speed NE and the intake pipe pressure PM using the map eight, but in a vehicle equipped with an automatic transmission ( As shown in Figure 8-4, even if the idle condition is met, vibrations may occur depending on whether the shift position of the transmission is in the neutral position (N range) or the drive position (D range). Since V is different after one novel, for example, as shown in FIG. 9(a), in the above-mentioned step 150 of predicting the vibration level LV, it is necessary to judge whether the shift position is N range, DL, or N range]5
2) If it is the N range (L), use the map Affl mentioned above to predict the vibration level LVt (~ (step 154); if it is the D range, use the map B preset for the D range shown in FIG. 9(b). It is desirable to estimate the bell LV by vibrating using the vibration level LV (step 156).The reason is that the vibration level LV is different between the N range and the D range because the vibration transmission system is different in each range.

Furthermore, since the vibration level [V of the engine 10 can be suppressed by increasing the engine speed NE, for example, as shown in FIG. If the shift position is in the N range or the D range in step 310, the shift position increases the engine speed NE. However, if the N range is safe, the engine speed NE When the shift position is in a range where it would be dangerous to increase the engine speed NE, the target capacity V of the A/C combination unit 31 is set as in the above embodiment.
It is also possible to correct the amount of co to suppress engine vibration.

[Effects of the Invention] As detailed above, the capacity control device for an engine-driven compressor of the present invention limits the capacity of the compressor COM when engine vibration becomes large during low rotation of the engine E/G. As a result, the engine load can be reduced, and engine vibration and vehicle vibration can be satisfactorily suppressed.

[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 an explanatory diagram explaining map A for determining the vibration level LV from intake pipe pressure PM and engine speed NE, and FIG. 5 is an explanatory diagram showing the relationship between engine speed, load torque, and engine vibration. 6(a) is a diagram showing the relationship between engine speed NE, capacity Vc, and engine vibration, and FIG. 6(b) is a diagram showing the relationship between engine speed NE, capacity Vc, and engine vibration.
A diagram showing the relationship between E, high-pressure refrigerant pressure Pb, and engine vibration, Figure 7 is a diagram explaining another example of capacity control, and Figure 8 shows the state in which the vibration level is different between the D range and the N range. FIG. 9 is an explanatory diagram illustrating another example of the method of calculating the vibration level LV, and FIG. 10 is an explanatory diagram illustrating another example of the method of suppressing engine vibration. E/G, 10...Engine COM, 31...Variable displacement compressor M1...
Capacity control means M2-... Vibration detection means M3... Capacity limiting means 15... Idle switch 18...
Pressure sensor 23...Rotation angle sensor 30...Air conditioner 41...Capacity sensor 42...High pressure pressure sensor 43...Low pressure sensor 45...Air conditioner switch 46...Vehicle speed sensor 50...・Electronic control unit (ECU)

Claims (1)

[Claims] A capacity control device for an engine-driven compressor, comprising capacity control means for controlling the capacity of a variable capacity compressor driven by a vehicle engine to compress and discharge refrigerant in accordance with a cooling load or a frost state of an evaporator. a vibration detection means for directly or indirectly detecting engine vibration based on the operating state of the engine; and a vehicle vibration detection means for detecting the capacity of the compressor controlled by the capacity control means in a predetermined low rotation range of the engine. A capacity control device for an engine-driven compressor, comprising: a capacity limiting means for limiting the engine vibration so that the larger the engine vibration is, the smaller the engine vibration is detected.