JP4624853B2 - Air conditioner control device for vehicle - Google Patents

Description

  The present invention relates to a control device for an air conditioner (air conditioner) whose compressor is driven by an engine of a vehicle such as an automobile.

An air conditioner provided in a vehicle such as an automobile drives a compressor using power extracted from an engine and obtains a cooling effect or the like using a known refrigeration cycle.
In addition, an air conditioner for vehicles is known as an auto air conditioner that is controlled so that the temperature in the passenger compartment to be air-conditioned substantially matches the temperature set by the user (for example, Patent Document 1, Patent). Reference 2).

In addition, when the air conditioner decelerates while cutting the fuel while the lockup clutch of the transmission is locked up, the auto air conditioner is decelerating and improves the fuel efficiency. It is known to stop driving and to increase the operating rate of the compressor at a high speed while the vehicle is decelerating to compensate for insufficient cooling capacity and the like (for example, Patent Document 3).
In addition, an auto air conditioner is known that performs a cold storage operation when the vehicle is running, and changes the state of the refrigeration cycle during idling or idle stop to perform air conditioning using the stored refrigerant. (For example, Patent Document 4).
JP-A-10-6736 JP 2003-341333 A JP 2001-330141 A JP 2004-34864 A

In recent years, further reduction in fuel consumption has been demanded for vehicles. The so-called fuel consumption (fuel consumption rate) refers to the case where the fuel consumption per unit work (shaft output, etc.) of the engine alone is shown, and the case where the vehicle travel distance per unit fuel is shown (actual fuel consumption). However, since the latter is affected by the operation of the air conditioner, there is a demand for improving the actual driving fuel consumption in the control of the air conditioner.
The subject of this invention is providing the air-conditioner control apparatus for vehicles which improves the actual driving | running | working fuel consumption of a vehicle.

The present invention solves the above-described problems by the following means.
The invention of claim 1 is driven by the engine, the control apparatus of the air conditioner for a vehicle having a compressor which is operated by switching between restriction mode that is limited functionality than the normal mode and the normal mode, torque of the engine an engine load detecting section for judging that the high-load condition is greater than the threshold value, the compressor increases for the case the frequency of the other to be operated in the normal mode when the engine is in the high load state A vehicular air conditioner control device comprising a compressor control unit.

The invention of claim 2 is driven by the engine, the control apparatus of the air conditioner for a vehicle having a compressor which is operated by switching between restriction mode that is limited functionality than the normal mode and the normal mode, torque of the engine an engine load detecting section for judging that the high-load condition is greater than the threshold value, a deceleration state detection unit for detecting a decelerating state of the vehicle, the deceleration and when the vehicle the engine is in the high load state is in a predetermined And a compressor control unit that increases the frequency at which the compressor is operated in the normal mode more than in other cases when in the state.

According to a third aspect of the present invention, in the vehicle air conditioner control device according to the first or second aspect, the compressor control unit switches the normal mode and the limit mode of the compressor based on a predetermined temperature condition. The vehicle air conditioner control device has a function and changes the frequency of operation in the normal mode by changing the temperature condition.
According to a fourth aspect of the present invention, in the vehicular air conditioner control device according to any one of the first to third aspects, the engine load detector is set to at least one of an intake pipe negative pressure and a throttle position. Based on this, it is determined whether or not the engine is in the high load state.

According to the present invention, the following effects can be achieved.
(1) Generally, in a four-stroke internal combustion engine that adjusts the output by restricting the intake air using a throttle valve or the like, the pumping loss generated from the exhaust stroke to the intake stroke increases in the low load region, and at the same time, the combustion gas As a result, the cooling loss due to heat transfer from the cylinder block to the cylinder block and the like also increases, so the thermal efficiency decreases and the fuel consumption rate decreases.
On the other hand, in the case of the present invention, the pumping loss and the cooling loss are small, so the frequency at which the compressor is operated in the normal mode in the high load state where the engine thermal efficiency is high and the fuel consumption rate is improved is increased. Therefore, assuming that the required cooling capacity (work volume) is the same, this cooling capacity can be demonstrated with less fuel consumption than when no control is performed for engine load changes. Deterioration of actual driving fuel consumption due to use can be suppressed.
Furthermore, the engine can be used in a region with higher thermal efficiency by actively operating the compressor in the normal mode during acceleration of the vehicle and increasing the load on the engine.
(2) Since the frequency at which the compressor is driven in the normal mode when the vehicle is in a decelerating state is increased, for example, the kinetic energy of the vehicle that has been discharged out of the vehicle as heat energy from the brake is utilized as the driving force of the compressor It is possible to reduce the driving load of the compressor during constant speed driving and improve the fuel consumption rate of the vehicle.

  The present invention aims to provide a vehicle air conditioner control device that improves the actual driving fuel consumption of a vehicle, in other cases where the temperature condition for determining whether to drive or stop the compressor is high when the engine is heavily loaded and when the vehicle is decelerated. The problem is solved by increasing the frequency of driving the compressor.

Embodiments of a vehicle air conditioner control apparatus to which the present invention is applied will be described below.
In this embodiment, the vehicle is an automobile such as a passenger car and has a 4-stroke gasoline engine. In this gasoline engine, intake air is throttled by a throttle valve provided in an intake system, and the negative pressure in the intake port is adjusted to control the output.

Moreover, the air conditioner (refrigeration air conditioner) with which this vehicle is equipped utilizes the refrigerating cycle using refrigerant | coolants, such as R134a, for example. In this refrigeration cycle, gas-phase refrigerant is compressed by a compressor driven by power extracted from the engine, and the compressed refrigerant is cooled and liquefied by a condenser provided at the front end of the vehicle. Then, liquid phase refrigerant is sprayed from the expansion valve into the evaporator, and the air introduced into the passenger compartment is cooled and dehumidified by the evaporator.
The compressor switches between a state driven by the power obtained from the engine (normal mode) and a state where the power from the engine is disconnected by a magnet clutch, which will be described later, and the drive is stopped (limit mode). While driving.

FIG. 1 is a block diagram illustrating a configuration of an air conditioner control device according to the present embodiment.
The air conditioner control device 1 is configured as a system including an air conditioner (AC) control unit 10, an air conditioner (AC) control panel 20, an engine control unit (ECU) 30, and a body integrated unit 40.

The AC control unit 10 includes a CPU having an information processing function, and is a control unit that performs drive control of a compressor, which will be described later, and controls a blower motor, a door actuator, and the like (not shown).
The AC control unit 10 is connected to an inside air temperature sensor 11, a solar radiation sensor 12, and an evaporation thermosensor 13.

The inside air temperature sensor 11 is disposed, for example, in an instrument panel of a vehicle, senses the temperature inside the vehicle (indoor temperature), and transmits an electrical signal corresponding to the temperature to the AC control unit 10. The inside air temperature sensor 11 includes an aspirator (intake unit) (not shown) and a thermistor that is disposed in the aspirator and whose resistance value is inversely proportional to the temperature.
The solar radiation sensor 12 includes a photodiode that converts the intensity of sunlight received by the vehicle into a change in current, and transmits the output to the AC control unit 10. The solar radiation sensor 12 is provided, for example, on the upper surface of the dashboard of the vehicle.
The evaporation thermosensor 13 detects the temperature of air passing through an evaporator of an air conditioner unit (not shown) and transmits a signal corresponding to the temperature to the AC control unit 10.

The AC control unit 10 is connected to a magnet clutch relay 14.
The magnet clutch relay 14 supplies drive power to a magnet clutch 15 that intermittently transmits power from the crankshaft of the engine (not shown) to the compressor in response to a control signal output from the AC control unit 10.

  The AC control panel 20 is an operation unit mounted on an instrument panel or the like of the vehicle. The user inputs a set temperature in the auto mode, and manuals such as the air volume in the manual mode, the air blowing mode, the internal air circulation, and the defroster. The operation is performed.

The ECU 30 includes a CPU that comprehensively controls the vehicle engine, and transmits information related to the intake pipe negative pressure, the throttle position, and the vehicle speed to the AC control unit 10.
The intake pipe negative pressure is a pressure in the intake manifold, which is a region on the downstream side (engine body side) from the throttle valve of the intake system.
The throttle position is information related to the position of the throttle valve that opens and closes the intake pipe. For example, the throttle valve drive unit is provided with a position sensor such as an encoder, or an electronic control throttle (throttle-by-wire) is detected. In the case of a vehicle to be employed, detection may be performed based on a control signal of an actuator that drives a throttle.
The vehicle speed is calculated based on a vehicle speed pulse signal output from, for example, a vehicle speed sensor provided in a wheel hub portion of the vehicle.

The body integration unit 40 includes a CPU that controls various devices included in the vehicle body, and an outside air temperature sensor 41 and a lighting switch 42 are connected thereto.
The outside air temperature sensor 41 senses the outside air temperature using a thermistor and transmits a signal corresponding to this temperature to the AC control unit 10. The outside air temperature sensor 41 is attached to, for example, a radiator lower panel at the front end of the vehicle, and is provided with a cover of a resin molded product to increase its temperature capacity and prevent it from reacting sensitively to a sudden temperature change.
The lighting switch 42 is provided, for example, in a steering column section in a vehicle interior, and performs lighting / extinguishing operation of lights such as a headlamp.
The body integration unit 40 described above transmits inputs from the outside air temperature sensor 41 and the lighting switch 42 to the AC control unit 10.

Next, the operation in the auto mode of the air conditioner control device 1 described above will be described.
FIG. 2 is a flowchart showing the operation of the air conditioner control device 1.
Hereinafter, the steps will be described step by step.
(Step S01: Parameter input)
The AC control unit 10 receives the following parameters.
Set temperature: Tset
Inside temperature: Tr
Outside temperature: TAM
Solar radiation: Ts
Night illumination correction amount: Tn
Evaporation temperature: TE
Here, the set temperature Tset is input by the user through the AC control panel 20.
The inside air temperature Tr, the outside air temperature TAM, the solar radiation amount Ts, and the evaporation temperature TE are respectively detected by the inside air temperature sensor 11, the outside air temperature sensor 41, the solar radiation sensor 12, and the evaporation thermosensor 13.
The night illumination correction amount Tn is set according to the output of the lighting switch 42. When night illumination such as a headlamp is on, it is determined based on the night illumination on time, and is off. Is determined on the basis of this nighttime illumination off time.

(Step S02: Necessary blowing temperature TAO is determined)
The AC control unit 10 determines a necessary blowout temperature TAO that is a target temperature of air blown out from a blowout port (not shown) provided in the vehicle interior based on each parameter input in step S01.
When the set temperature Tset is at the lower limit (for example, 18.0 ° C.) and the upper limit (for example, 32.0 ° C.), the required blowing temperature TAO is TAO = −200 (MAX COOL), TAO = 200 (MAX), respectively. HOT), otherwise, it is determined based on Equation 1 below.

TAO
= Kset × Tset−Kr × Tr−Kam × TAM−Ks × Ts
+ Tn + C (Formula 1)
Kset = set temperature coefficient Tset = set temperature (° C)
Kr = Temperature temperature coefficient Tr = Temperature temperature (° C.)
Kam = outside air temperature coefficient TAM = outside air temperature (° C)
Ks = Solar radiation coefficient Ts = Solar radiation (Kcal / m ² · min)
C = constant Tn = night illumination correction amount

(Step S03: TAO-TAM judgment 1)
The AC control unit 10 determines whether or not the relationship between the required blow-out temperature TAO and the outside air temperature TAM satisfies the following formula 2, and if satisfied, proceeds to step S12, otherwise proceeds to step S04.

TAO-TAM ≧ 50 (Formula 2)

(Step S04: TE judgment)
The AC control unit 10 determines whether or not the evaporator temperature TE detected by the evaporator thermosensor 13 is 4 ° C. or higher, for example. If it is 4 ° C. or higher, the process proceeds to step S05. Proceed to S12.

(Step S05: TAO-TAM judgment 2)
The AC control unit 10 determines whether or not the relationship between the required blowing temperature TAO and the outside air temperature TAM satisfies the following expression 3, and if so, proceeds to step S06, otherwise proceeds to step S11.

50> TAO-TAM ≧ 45 (Formula 3)

(Step S06: engine high load state determination)
The AC control unit 10 determines whether or not the engine load is in a predetermined high load state based on the intake pipe negative pressure and the throttle position input from the ECU 30.
For example, the AC control unit 10 is high when one or both of the intake pipe negative pressure and the throttle position exceeds a preset threshold value and the engine torque is operated in a state larger than the state at the threshold value. Judged to be in a load state.
And when it is judged that it is a high load state, it progresses to Step S11, and when it is judged that it is not a high load state (low load state), it progresses to Step S07.

(Step S07: Deceleration state determination)
The AC control unit 10 determines whether or not the vehicle is in a predetermined deceleration state based on the vehicle speed input from the ECU 30.
For example, the AC control unit 10 determines that the vehicle is in a decelerating state when the vehicle speed is decreasing at a rate equal to or higher than a preset value with respect to time.
If it is determined that the vehicle is in a deceleration state, the process proceeds to step S11. If it is determined that the vehicle is not in a deceleration state, the process proceeds to step S08.

(Step S08: outside air temperature determination)
The AC control unit 10 determines whether or not the outside air temperature TAM input from the outside air temperature sensor 42 via the vehicle integrated unit 40 is, for example, 30 ° C. or more, and if it is 30 ° C. or more, the process proceeds to step S11. If it is less than 30 ° C., the process proceeds to step S09.

(Step S09: Judgment during traffic jam)
The AC control unit 10 determines whether or not the vehicle is in a congested state of a very low speed traveling subject based on the vehicle speed and the throttle position time history input from the ECU 30 and the ON input frequency of an idle switch (not shown). If it is determined that the vehicle is in a state, the process proceeds to step S11. If it is determined that the traffic is not congested, the process proceeds to step S10.

(Step S10: AC operation restriction)
The AC control unit 10 outputs a control signal to the magnet clutch relay 14, disconnects the magnet clutch 15 and stops driving the compressor, and stops a blower motor (not shown) to stop blowing into the vehicle interior. .

(Step S11: AC normal operation)
The AC control unit 10 outputs a control signal to the magnet clutch relay 14, connects the magnet clutch 15 to drive the compressor, and operates a blower unit motor (not shown) to blow air into the vehicle interior.

(Step S12: AC operation restriction)
The AC control unit 10 outputs a control signal to the magnet clutch relay 14, disconnects the magnet clutch 15 and stops driving the compressor, and stops a blower motor (not shown) to stop blowing into the vehicle interior. .

Next, the effect of this embodiment will be described in comparison with a comparative example. In addition, about a comparative example, description is abbreviate | omitted about the part similar to an Example, and difference is mainly demonstrated.
FIG. 3 is a graph showing an example of the vehicle speed and the history of the air conditioner flag when the vehicle provided with the air conditioner control device according to the present invention is running. This comparative example is different from the example in that the judgment corresponding to step S06 and step S07 in FIG. 2 of the example is not performed.

In FIG. 3, the horizontal axis indicates time (seconds), and the vertical axis indicates the vehicle speed (km / h) and the air conditioner flag (0 or 1). The air conditioner flag is 1 when the compressor and the blower are driven, and 0 when the compressor and the blower are stopped.
In the example of FIG. 3, the compressor is driven and stopped regardless of whether the vehicle is accelerating, traveling at a constant speed, decelerating, or stopping (idling), and the compressor is stopped during acceleration / deceleration. There are belts and time zones during which the compressor is operating during constant speed running and stopping.

On the other hand, FIG. 4 is a graph showing an example of the history of the vehicle speed and the air conditioner flag when the vehicle equipped with the air conditioner control device of the present embodiment is running, and the horizontal axis is time (seconds) as in FIG. The vertical axis indicates the vehicle speed (km / h) and the air conditioner flag (0 or 1).
In the example of FIG. 4, the total drive time of the compressor is substantially the same as that of FIG. 3, but the compressor is driven while the vehicle is accelerating and decelerating, and the compressor is stopped during constant speed traveling and stopping. Like to do.

FIG. 5 is a graph showing an example of the relationship between the engine speed and torque of the vehicle and the fuel consumption rate.
In FIG. 5, the horizontal axis indicates the engine speed (rpm), the vertical axis indicates the engine torque, and the higher the value, the higher the engine load. The fuel consumption rate here indicates the weight (g) of fuel (gasoline) necessary for 1 kwh work.

As shown in FIG. 5, it can be seen that the fuel consumption rate decreases as the torque increases (good fuel consumption), and the thermal efficiency is improved. This is mainly because the engine output is adjusted by the intake throttle by the throttle valve, so that the pumping loss (pump loss) generated from the exhaust stroke to the intake stroke becomes smaller as the load increases. Further, there is an influence due to a decrease in the ratio of the cooling loss to the total generated heat amount as the load becomes higher.
The fuel consumption rate starts to increase (deteriorates) when the torque further increases (higher load) after the fuel consumption rate takes the minimum value as the torque increases, but this increases the output near the fully open area. In addition, the mechanical loss increases due to the fact that the air-fuel ratio (A / F) is made rich in order to obtain a cooling effect due to the latent heat of vaporization of the fuel, and that the piston ring tension increases as the combustion gas pressure increases. It depends. However, it is rare to use such a fuel-rich region in actual general traveling, and it can be considered that the higher the load is, the better the fuel consumption rate is in practice.
On the other hand, the relationship between the engine speed and the fuel consumption rate is, for example, the best fuel consumption rate in the medium speed range of about 2500 to 3000 rpm, and worse on the higher speed side due to an increase in mechanical loss due to friction, etc. On the low speed side, the deterioration is caused by an increase in cooling loss due to heat conduction from the combustion gas to the cylinder block, head, etc., but focusing on the relationship between the fuel consumption rate and torque (load) for each rotation range, as described above It can be seen that the higher the load, the better the fuel consumption rate.

表１に示すように、単位時間コンプレッサを駆動するのに必要な燃料の量は、定速時には３ｃｃであるのに対して加速時には２ｃｃとなるから、加速時にコンプレッサを駆動したほうが燃料消費量を低減することができる。 From the above, if the compressor is driven during acceleration of a vehicle with a relatively high engine load and when driving at a constant speed with a relatively low load, the amount of fuel consumed to cause the compressor to perform the same work Shows that there is less during acceleration.
Table 1 is a table showing an example of fuel consumption per unit time when the air conditioner is turned off or on at constant speed and acceleration, and an increase in fuel consumption due to turning on the air conditioner. is there.

As shown in Table 1, the amount of fuel required to drive the compressor per unit time is 3 cc at constant speed, but 2 cc during acceleration. Therefore, driving the compressor during acceleration reduces fuel consumption. Can be reduced.

  Further, when the vehicle is decelerated, the engine performs fuel cut as much as possible, and is operated with a so-called engine brake. This is a state where the fuel supply (fuel injection) to the engine is stopped and the crankshaft of the engine is rotated by the input from the drive system of the vehicle. At this time, the engine is negative due to pumping loss and mechanical loss. Generate work. That is, the engine is in a state of absorbing input from the drive system. Accordingly, when the compressor is driven in such a state, no fuel is consumed. In this case, the effectiveness of the so-called engine brake is increased by the amount of work required to drive the compressor, so the amount of foot brake used is reduced as the amount of work increases. It is possible to recover energy released as heat from the compressor as power for the compressor.

From the above, in this embodiment, the following effects can be exhibited with respect to the comparative example.
(1) Since the frequency at which the compressor is driven in a high load state where the fuel consumption rate of the engine is increased, the same cooling capacity can be obtained with a small amount of fuel consumption, and the fuel consumption due to the operation of the air conditioner By suppressing this increase, the actual driving fuel consumption of the vehicle can be improved. In particular, in the intermediate period excluding extreme heat such as July and August, the required cooling capacity is relatively low, and most of it is obtained when the engine is in a high load state and the vehicle is in a deceleration state. Therefore, a high effect can be obtained.
(2) Since the frequency of driving the compressor is increased when the vehicle is in a deceleration state where fuel cut is performed, the compressor can be driven without fuel consumption, and the actual driving fuel consumption of the vehicle is improved. can do.
(3) When the engine is heavily loaded and when the vehicle is decelerating, the internal air temperature tends to decrease by increasing the drive frequency of the compressor more than in other cases. This produces temperature fluctuations that are said to be ergonomically superior. As a result, a fluctuation effect similar to fuzzy control used in home (building) air conditioners or the like can be obtained.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) In the embodiment, the compressor is stopped when the function of the compressor is limited. However, the present invention is not limited to this. For example, in the case of a variable displacement compressor, the capacity (discharge amount) is limited in the limit mode. You may make it reduce rather than normal mode.
(2) In the embodiment, the drive frequency in the normal mode of the compressor is switched to two stages, but it may be switched to more stages or continuously variable.
(3) The conditions for switching between driving and stopping of the compressor are not limited to those using the above-described TAO-TAM, and other conditions may be used. For example, it may be based on the relationship between the set temperature and the room temperature only.
(4) In the embodiment, the deceleration state is detected based on the vehicle speed signal. However, the present invention is not limited to this. For example, the ECU detects whether or not the fuel is cut from the engine, and the fuel is cut. In this case, it may be determined that the vehicle is decelerating.

It is a block diagram which shows the structure of Example 1 of the air-conditioner control apparatus to which this invention is applied. It is a flowchart which shows operation | movement of the air-conditioner control apparatus of FIG. It is a graph which shows an example of the log | history of the vehicle speed and air-conditioner flag at the time of driving | running | working of the vehicle provided with the air-conditioner control apparatus which is a comparative example of this invention. It is a graph which shows an example of the log | history of the vehicle speed and air-conditioner flag at the time of driving | running | working of the vehicle provided with the air-conditioner control apparatus of FIG. It is a graph which shows an example of the relationship between the rotation speed of an engine, a torque, and a fuel consumption rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air-conditioner control apparatus 10 Air-conditioner (AC) control unit 11 Internal temperature sensor 12 Solar radiation sensor 13 Evaporation thermo sensor 14 Magnet clutch relay 15 Magnet clutch 20 Air-conditioner (AC) control 30 Engine control unit (ECU)
40 Body integrated unit 41 Outside air temperature sensor 42 Lighting switch

Claims (4)

In a control device for a vehicle air conditioner having a compressor that is driven by an engine and is operated by switching between a normal mode and a limited mode in which the function is limited than the normal mode.
An engine load detector that determines that the engine is in a high load state when the engine torque is greater than a threshold ;
The vehicle air conditioner control apparatus characterized by comprising a compressor control unit for increasing the frequency of the compressor when the engine is in the high load state is operated in the normal mode for the other cases. In a control device for a vehicle air conditioner having a compressor that is driven by an engine and is operated by switching between a normal mode and a limited mode in which the function is limited than the normal mode.
An engine load detector that determines that the engine is in a high load state when the engine torque is greater than a threshold ;
A deceleration state detector for detecting a deceleration state of the vehicle;
If the case and the vehicle the engine is in the high load state is in a predetermined decelerating state, the frequency with which the compressor is operated in the normal mode comprise a compressor control unit for increasing than otherwise these An air conditioner control device for a vehicle. The vehicle air conditioner control device according to claim 1 or 2,
The compressor control unit has a function of switching between the normal mode and the limit mode of the compressor based on a predetermined temperature condition, and changes the frequency of operation in the normal mode by changing the temperature condition. A vehicle air conditioner control device. The vehicle air conditioner control device according to any one of claims 1 to 3,
The vehicle air conditioner control device, wherein the engine load detector determines whether or not the engine is in the high load state based on at least one of an intake pipe negative pressure and a throttle position.

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