JPH01278832A - Automobile air-conditioning device - Google Patents

Abstract

PURPOSE:To prevent a drop in engine rotational speed during return to fuel supply while ensuring minimum cooling ability by providing a means for changing the capacity of a compressor to a minimum value for a predetermined time during transition from the stop of fuel supply to the return to the fuel supply. CONSTITUTION:During deceleration of an engine 1, a fuel cut-off means stops the supply of fuel to the engine. During transition from the stop of fuel supply to the return to fuel supply, an actuator 25 is operated in response to an instruction signal from a control unit U so as to displace a suction port 23 opened to a side housing of a compressor 20 toward the rotationwise advancing side of a rotor 21 so as to set the capacity of the compressor 20 to a minimum value for a predetermined time. The load of the compressor 20 upon the engine is decreased to a value as small as possible during the period of return to fuel supply during which the fuel supply is unstable. As a result it is possible to prevent a drop in rotational speed of the engine 1 while ensuring a minimum cooling ability during return to fuel supply.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a cooling compressor used in automobiles, which is driven by an engine output shaft and whose capacity and refrigerant discharge capacity are variable. It is.

(Prior art) Some air conditioning control devices for automobiles are
As seen in Japanese Patent No. 15, a compressor in which the capacity of a compressor is variably controlled according to the required load is known. That is, for example, when the difference between the vehicle interior temperature and the target temperature is large, the capacity of the compressor is increased to increase the cooling capacity, and conversely, when the difference between the vehicle interior temperature and the target temperature is small, the compressor capacity is decreased. This is said to reduce cooling capacity.

According to this, compared to controlling a constant capacity compressor 0N10FFfi+J to adjust the temperature in the vehicle interior, there is an advantage that the liquid compression of the compressor can be reduced or the comfort of the vehicle interior air conditioning can be improved.

(Problems to be Solved by the Invention) By the way, when this variable capacity compressor is combined with so-called fuel cut technology, which stops the supply of fuel during deceleration, the following problems occur.

In the above-mentioned fuel cut technique, when the fuel supply is resumed after the fuel supply has been stopped, the inside of the cylinder is extremely cold immediately after the fuel supply is resumed, so combustion properties tend to become extremely unstable. For this reason, when a variable capacity compressor with an uncertain load on the engine is used, when the fuel supply is restored after a fuel cut, for example, when the compressor is operated at normal capacity, an excessive load may be placed on the engine. As a result, the engine speed changes immediately after the fuel supply is restored, and this appears as a shock.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an air conditioning control device for an automobile that suppresses fluctuations in engine speed immediately after fuel supply is restored.

(Means and effects for solving the problem) In order to achieve the above technical problem, the present invention provides a variable capacity compressor driven by an engine, and a variable capacity compressor that changes the capacity of the compressor according to the required load. A compressor capacity setting means for setting the compressor capacity, and a fuel cut means for stopping the supply of fuel during deceleration; Compressor capacity changing means for changing the capacity of the compressor to the minimum capacity.

In other words, immediately after returning to the supply of fuel with unstable combustibility, the compressor is set to the minimum capacity to minimize the load on the engine, thereby stabilizing combustion while ensuring the minimum cooling performance. I decided to wait until it was done.

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.

In FIG. 1, l is an engine body, and a combustion chamber 3 defined by a piston 2 includes an intake boat 4 and an exhaust boat 5.
is opened, the intake boat 4 is opened and closed by the intake valve 6,
The exhaust boat 5 is opened and closed by an exhaust valve 7. A spark plug 8 is also arranged in the combustion chamber 3,
The air-fuel mixture that has passed through the intake boat 4 and filled into the combustion chamber 3 is ignited by the spark plug 8, and the combustion gas 2 is
After performing the expansion work of pushing down the piston 2, it is discharged into the atmosphere through the exhaust boat 5 and an exhaust passage (not shown). In the intake passage 8 connected to the intake boat 4, a fuel injection valve P is disposed near the intake boat 4, a throttle valve 10 is disposed upstream of the fuel injection valve P, and fuel is supplied to the combustion chamber 3 through the intake passage 8. The amount of intake air to be filled is determined by the air flow meter 11.
detected by.

A crankshaft 12, which is the output shaft of the engine I, is connected to the piston 2 via a connecting rod 13, and a compressor 20 is connected to the crankshaft 12 via a pulley 14, a belt 15, and an electromagnetic clutch 16. The compressor 20 constitutes one component of the refrigeration cycle, and is here a vane type compressor, and its working chamber 20a is formed by an eccentric rotor 21 and vanes 22. Then, either one of the suction port 23 and the discharge port 24 opened in the side housing of the compressor 20, in this case the suction port 23, can be displaced by an actuator 25 toward the advancing side in the rotational direction (arrow direction) of the rotor 21. , the compressor 20 has a variable capacity. That is, the suction port 23
1, when the stroke is made in the forward direction of rotation (indicated by the imaginary line in the figure), the capacity becomes small, and conversely, when the stroke is made in the lag side (indicated by the solid line in the figure), the capacity becomes large.

Capacity control of the compressor 20 is performed by a control unit tJ consisting of, for example, a microcomputer. In order to generate such control signals, the control unit U receives the vehicle interior temperature from the vehicle interior temperature sensor, the ON10FF signal from the air conditioner switch, and the set temperature from the vehicle interior temperature setting switch.

In addition, the fuel supply to the engine 1 is stopped during deceleration, and the control unit U receives the engine speed from the sensor 30 and the throttle opening from the sensor 3I, and performs the fuel cut as shown in FIG. In this region, the fuel supply to engine l is stopped. Since this fuel cut control is the same as the conventional one, further explanation will be omitted.

To give an overview of the capacity control of the compressor 20, first, as normal control, the capacity of the compressor 20 is set to a required capacity according to the required heat load of the air conditioner (hereinafter referred to as compressor normal control).

On the other hand, when the engine 1 escapes from the fuel cut area during deceleration, that is, when the fuel supply to the engine 1 is restored, control is applied to reduce the capacity of the compressor 20 to the minimum capacity at once for a certain period of time. ing. below,
An example of this control will be explained based on the flowchart shown in FIG.

First, step S! It is determined whether or not a timer, which will be described later, is operating. If the timer is N'O, the process proceeds to step S2, where the throttle opening degree TVO and engine speed Ne are read, and then, in the next step S3, the air conditioner switch is Determine whether or not is turned on, and select No.
If so, the process moves to step S4, where the electromagnetic clutch 16 is turned off and the compressor 20 is put into a non-operating state. On the other hand, when it is determined in step S3 that the air conditioner switch is ON, step S5
It is determined whether or not the fuel cut area has been exited.
When O, the process advances to step S6 and the compressor 20
is operated under the above-mentioned normal control.

On the other hand, when it is determined in step S5 that the fuel cut area has been exited, the process proceeds to step S7, where a timer is set, and then, in step S8, the capacity of the compressor is set to the minimum capacity for a certain period of time. As a result, when the fuel supply is restored when the fuel condition is unstable, the load of the compressor 20 on the engine 1 is reduced as much as possible, and as a result, the generation of an overload condition on the engine 1 is avoided, and the engine speed is reduced. This will prevent the product from falling. The above control can be expressed as a timing chart as shown in FIG. 4.

Incidentally, FIG. 5 corresponds to the above step S6 and shows the contents of the compressor normal control. Here, in the compressor normal control, when the required capacity VT and the actual damage lv are different, the actual damage 1v is gradually changed to the required capacity IVT. That is, first, in step S20, the required capacity (■) of the compressor is set, and in the next step S21, this required capacity ff1VT and the current actual damage I are set.
When the required capacity VT is larger than the actual capacity (2), control is performed to gradually increase the actual capacity (2) to the required capacity VT through steps S22 and S23. Conversely, when the required capacity VT is smaller than the actual damage 1v, steps S24, S25, and Step 3 are performed.
Control is performed to gradually reduce the actual capacity (2) to the required capacity VT through 26. Further, as this compressor normal control, the capacity of the compressor 20 may be set to the maximum capacity until the vehicle interior temperature reaches the set temperature, and after reaching the set temperature, the capacity of the compressor may be set to the required capacity. . In this way, the compressor 20 is operated at maximum capacity until the temperature inside the vehicle reaches the set temperature, so that it is possible to improve the efficiency of cooling the vehicle interior. However, when transitioning from the minimum capacity control of the compressor 20 to the normal control of the compressor 2 when exiting the fuel cut region, it is necessary to gradually increase the capacity to the required capacity in order to prevent large load fluctuations on the engine 1. preferable. Further, in order to avoid a delay in changing the capacity of the compressor 20, the control to reduce the capacity of the compressor 20 to the minimum capacity may be started immediately before leaving the fuel cut region.

(Effects of the Invention) As is clear from the above description, according to the present invention, it is possible to prevent the engine rotational speed from dropping when the fuel supply is restored while ensuring the minimum cooling performance.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram of an air conditioning control system for an automobile according to an embodiment, FIG. 2 is a diagram showing an area where fuel supply is stopped during deceleration, and FIG. 3 is a flowchart showing an example of control. FIG. 4 is a timing chart showing control details over time. FIG. 5 is a flowchart showing an example of compressor normal control. 1: Engine body 12: Electromagnetic clutch 20: Compressor 23: Compressor suction port 25: Actuator U: Control unit Fig. 2 Fig. 4 Fig. 3

Claims (1)

[Claims] (1) In an air conditioning control system for an automobile, which includes a variable speed compressor driven by an engine and a compressor capacity setting means for setting the capacity of the compressor according to the required load, the fuel supply is stopped during deceleration. An air conditioning control for an automobile, comprising: a fuel cut means; and a compressor capacity change means for changing the capacity of the compressor to a minimum capacity for a predetermined period of time during a transition period from stopping fuel supply to returning. Device.