JPH07266842A - Air conditioning control device for vehicle - Google Patents

Abstract

PURPOSE:To conduct air conditioning operation at preliminary starting of an engine without giving occupants any feeling of physical disorder in a vehicle which has a preliminary starting device capable of starting an engine before the occupants ride in. CONSTITUTION:The air blowing quantity control characteristic of an air blowing means 8 for air conditioning is changed from a usual characteristic (a) to a preliminary starting characteristic (b) to increase an air blowing quantity when a preliminary starting operation signal SP is generated from the preliminary start control circuit part 51 of a preliminary starting device 50, thereby quickly approaching a cabin temperature to a set temperature. Thereby, air conditioning at the time of the preliminary start of an engine can be improved without generating any feeling of physical disorder due to the change of a set temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning control device for use in a vehicle having a pre-starting device capable of starting the vehicle running engine before the passenger is boarded in the vehicle.

[0002]

2. Description of the Related Art Conventionally, a vehicle air-conditioning control device of this type has been proposed in Japanese Unexamined Patent Publication (Kokai) No. 62-8814. In this conventional device, when the engine is in the pre-starting state by the operation of the pre-starting device, The aim is to improve the comfort by displacing the set temperature of the air conditioning control by a predetermined value by the displacement means.

[0003]

However, since the set temperature is originally for determining the desired temperature of the occupant and for controlling the temperature of the air-conditioning control target (vehicle interior), the set temperature is set as described above. If the temperature is changed while ignoring the occupant's taste, the occupant feels uncomfortable immediately after boarding, which is not preferable in terms of air conditioning feeling.

In view of the above points, the present invention does not change the set temperature at the time of pre-starting the engine so that the temperature inside the vehicle can reach the set temperature early by changing the air flow rate control characteristic, and thus immediately after riding. The purpose is to improve the feeling of air conditioning.

[0005]

In order to achieve the above object, the present invention uses a vehicle running engine in a vehicle having a pre-starting device which can be started before an occupant gets on the vehicle. In the air-conditioning control device, a determination means for determining whether or not the vehicle running engine is pre-started by the pre-starting device, and this determination means,
When it is determined that the vehicle traveling engine is in the pre-start state, the pre-start characteristic (shown in FIG. 3) in which the air-blowing amount control characteristic of the air-conditioning blower means is larger than the normal-state characteristic (characteristic a in FIG. 3). The technical means of including the changing means for changing to the characteristic b) is adopted.

[0006]

According to the invention as set forth in claim 1, since it has the above-mentioned technical means, when the engine is pre-started by the pre-starting device, the interior of the room can be quickly brought close to the set temperature by increasing the air flow. Therefore, there is a great effect that the passenger does not feel uncomfortable due to the change of the set temperature and the air conditioning feeling in the vehicle with the pre-starting device can be improved.

According to the second aspect of the present invention, it is determined whether or not the temperature difference between the target temperature for vehicle compartment temperature control and the actual vehicle compartment temperature is within a predetermined value. If it is determined that the value is within the predetermined value, the air flow rate control characteristic of the air conditioning blower is set to the normal characteristic (characteristic a in FIG. 3) even if the vehicle running engine is in the pre-start state. Therefore, when the passenger compartment temperature approaches the set temperature, there is an effect that the air flow rate control is automatically switched to the normal characteristic to reduce the air flow rate and the power consumption and noise of the air blower can be reduced. .

According to the third aspect of the present invention, it is determined whether or not an occupant is on the vehicle, and when it is determined that the occupant is in a boarding state, the air flow rate control of the air conditioning blower means is performed. Since the characteristic is set to the characteristic at the normal time (characteristic a in FIG. 3), there is an effect that the occupant does not feel uncomfortable due to an increase in air flow when boarding. Further, according to the invention of claim 4, since the control of the inventions of claims 2 and 3 are combined, an effect due to the combination can be exhibited.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes an entire ventilation system of a vehicle air conditioner, and the main body of the ventilation system 1 is disposed below a vehicle interior instrument panel of an automobile. The ventilation system 1 is roughly divided into a ventilation unit 2 and an air conditioning unit 3, and the ventilation unit 2 is arranged in front of the passenger seat.
An inside / outside air switching box 4 is provided above the blower unit 2. The ventilation system 1 constitutes an air-conditioning air passage for air-conditioning the air inside or outside the vehicle and introducing the air into the vehicle.

The inside / outside air switching box 4 is formed with an inside air intake port 5 and an outside air intake port 6, and further the inside air intake port 5 is formed.
In a portion where the outside air intake port 6 and the outside air intake port 6 are separated, an inside / outside air switching means for selectively opening and closing both intake ports, specifically, a shaft 7a rotatably supported by the inside / outside air switching box 4, and a shaft 7
The inside / outside air switching door 7 fixed to a is provided.
Further, a servo motor 7b as an inside / outside air driving means for driving the shaft 7a is connected to the shaft 7a,
The inside / outside air switching door 7 is driven by driving the servo motor 7b.
Works.

Further, the inside air (air inside the vehicle) is sucked into the inside / outside air switching box 4 from the inside air inlet 5 provided on the passenger side, and the outside air (air outside the passenger compartment) is introduced into the outside air from the vehicle side outside air inlet (not shown). The air is sucked into the inside / outside air switching box 4 through the suction port 6. A centrifugal electric blower 8 as a blower is provided below the inside / outside air switching box 4, and the blower 8 includes a centrifugal fan 9, a driving motor 10 for the centrifugal fan 9, and a scroll casing 11 accommodating the centrifugal fan 9. It consists of and.

Reference numeral 12 denotes a case of the air conditioning unit 3, which is arranged at a substantially central portion in the left-right direction of the vehicle compartment and is connected to an air outlet side portion of the scroll casing 11. An evaporator 14 that serves as an air cooling means and a heater core 15 that serves as an air heating means are provided downstream of the case 12 on the upstream side of the case 12. In addition, a bypass passage 16 is formed in the case 12 so that the cold air cooled by the evaporator 14 bypasses the heater core 15.

The evaporator 14 is a compressor 17 and a condenser 1.
A well-known refrigeration cycle 2 which is pipe-connected together with 8, a liquid receiver 19, and a pressure reducer (specifically, a temperature-operated expansion valve etc.) 20.
1 is a heat exchanger, which dehumidifies and cools the air in the case 12. The compressor 17 is connected to an engine E of an automobile via an electromagnetic clutch 22, and the drive stop is controlled by controlling the electromagnetic clutch 22 to be intermittent. The heater core 15 is a heat exchanger that uses the cooling water of the automobile engine as a heat source, and reheats the cold air cooled by the evaporator 14.

A shaft 23a rotatably supported with respect to the case 12 is provided at an air upstream side portion of the heater core 15.
And the air mix door 23 fixed to the shaft 23a
And are provided. The air mix door 23 adjusts the amount of the cool air cooled by the evaporator 14 to the heater core 15 and the amount of the cool air to the bypass passage 16 according to the rotational position of the air mix door 23. With the air mix door 23, the shaft 23a, and the bypass passage 16,
A temperature adjusting means for adjusting the temperature of the air blown into the passenger compartment is configured. Also, the shaft 2 of the air mix door 23
A servo motor 23b as a driving means for driving the shaft 23a is connected to 3a, and the air mix door 23 is operated by the drive of the servo motor 23b.

In the case 12, air outlets 24, 25, 26 for guiding air to various air outlets into the passenger compartment are formed at the downstream end of the ventilation passage. Here, the air outlet 24 is connected via a face duct (not shown) to a face outlet (not shown) that is opened at a position facing the upper body of the passenger in the vehicle compartment. Also the air outlet 25
Is connected via a foot duct (not shown) to a foot outlet (not shown) that is open at a position facing the foot of the passenger in the vehicle compartment. The air outlet 26 is connected via a defroster duct 27 to a defroster outlet 28 opened on the dashboard in the front seat of the vehicle. The conditioned air blown from each of the blowout ports is blown toward the upper body of the occupant, the feet, and the inner surface of the windshield 29.

At the inlet portions of the air outlets 24, 25, 26 described above, outlet opening / closing means for selectively opening / closing the outlets, specifically, a shaft rotatably supported with respect to the case 12. Doors 30, 31, 32 fixed to 30a, 31a, 32a are provided. Each of the shafts 30a, 31a, 32a is provided with a servo motor 30b, 31 as a driving means for driving the shaft.
b and 32b are connected, and these servomotors 3
By driving 0b, 31b, 32b, the doors 30,
31 and 32 are activated. Reference numeral 23d is a door opening detection means provided in the servo motor 23b for detecting the opening θ of the air mix door 23, and specifically, the servo motor 2
3 is a potentiometer showing a change in electrical resistance according to the rotation angle.

Reference numeral 41 is an inside air temperature sensor for detecting the temperature Tr of the air inside the vehicle, 42 is an outside air temperature sensor for detecting the temperature Tam of the air outside the vehicle, 43 is a solar radiation sensor for detecting the amount of solar radiation Ts entering the vehicle interior, and 44 is This is a temperature setting device for an occupant to manually set a desired temperature Tset in the passenger compartment. Again 45
Is a sensor that detects the cooling degree Te of the evaporator 14, and is specifically a thermistor that is provided at a portion of the evaporator 14 immediately after the air is blown and that detects the air temperature immediately after passing through the evaporator 14. Reference numeral 46 denotes a sensor that detects the degree of heating of the heater core 15, and is specifically a water temperature sensor that is attached to the tank or the heater pipe of the heater core 15 and indirectly detects the temperature of the engine cooling water.

Reference numeral 47 denotes an inside / outside air switch which constitutes an inside / outside air switching means for manually setting the inside / outside air switching in the air suction mode, and in the present embodiment, it comprises two switches, an inside air switch and an outside air switch. Reference numeral 48 is a diff mode switch which serves as diff mode setting means for manually setting the defroster mode,
Reference numeral 49 is an auto switch that constitutes an auto air conditioner setting means for setting the auto air conditioner, and although not shown in the air conditioning control panel P on which these switches 47, 48, 49, etc. are installed, a face mode, a foot mode, etc. Blowout mode setting means, etc. are also installed. Reference numeral 50 denotes a pre-starting device for the vehicle-driving engine E. In this example, a pre-start control circuit section 51 mounted on the car and a remote controller 52 for giving an operation signal to the circuit section 51 by a wireless method.
The pre-starting operation signal SP of the circuit section 51 is given to the starter control circuit 53 to operate the starter S of the engine E, and also inputted to the microcomputer 54 described later. . 55
Is a door switch as boarding detection means for detecting the presence / absence of boarding of an occupant in the vehicle, and detects the presence / absence of boarding of the occupant by opening / closing the door of the vehicle.

Signals from the respective devices such as the above-mentioned respective sensors and setting devices are converted into digital signals through a multiplexer and an A / D converter (not shown), and the microcomputer 5
4 is input. The microcomputer (air conditioning controller) 54 includes a central processing unit (CPU) 54a, a read only memory (ROM) 54b, a random access memory (RAM) 54c, an input / output port (I / O, not shown).
And the like, for example, after the ignition switch of the engine E is turned on, the drive motor 10, the servomotor 7b,
The drive circuits 7c, 10a, 22a, 23c, 30 are respectively provided to the 23b, 30b, 31b, 32b and the electromagnetic clutch 22.
A control signal is output via c, 31c, and 32c to control ON / OFF of each door 7, 23, 30, 31, 32, blower 8, and compressor 17.

Next, the operation of this embodiment will be described with reference to the flow chart of FIG. 2. In the air conditioning control panel P, the auto switch 49 is turned on by the manual operation of the occupant to select the auto air conditioner state, or The pre-start control circuit unit 5 is manually operated by the remote controller 52.
When the pre-start operation signal SP is generated from the circuit section 51, the microcomputer 54 is supplied with power and starts the air conditioning control program, and first, in step S1, initialization of data, timer, flag and the like is performed. Perform processing.

Next, in step S2, the temperature setter 44
A / D converted value from the signal from A / D converter Tset
Read. Then, in step S3, the signals Tr, Tam obtained by A / D converting the signals from the inside air temperature sensor 41, the outside air temperature sensor 42, the solar radiation sensor 43, the post-evaporation sensor 45, and the water temperature sensor 46 by the A / D converter. , Ts, Te and Tw are read respectively. Further, the door opening / closing signal from the door switch 55 and the pre-start operation signal SP from the pre-start control circuit unit 51 are read. These read data are R
It is stored in the AM 54c.

Next, in step S4, the RAM 54 is
The target outlet temperature (TAO) of the air blown into the passenger compartment is calculated based on the various data stored in c and the following mathematical formula 1 stored in the ROM 54b.

[0023]

## EQU1 ## TAO = Kset × Tset−Kr × Tr−Kam ×
Tam−Ks × Ts + C (Kset, Kr, Kam, Ks, and C are constants for correction) Next, in step S5, the prestart operation signal SP from the prestart control circuit unit 51 read and stored in step S3 is used. Based on the result, it is determined whether or not the engine E is being pre-started. If it is determined that the engine E is not being pre-started, the process proceeds to step S6 and subsequent steps to perform normal air conditioning control. That is, in steps S6, S7, and S8, the applied voltage Ve to the blower motor 10, the suction port (inside / outside air switching) mode, and the air outlet mode to the vehicle compartment are set based on the calculated target blown air temperature TAO. It is determined according to the characteristic diagrams shown in FIGS.

Here, a in FIG. 3 shows a control characteristic of the blower motor 10 voltage Ve during the normal control of the air conditioning, and the blower motor voltage Ve is controlled according to the characteristic a (blower amount control).
Is done. The FOOT in FIG. 5 is a foot mode in which the air outlet 25 at the bottom of the case 12 is opened and air is blown out from the foot outlet at the foot of the occupant, and B / L opens both upper and lower air outlets 24, 25. In this bi-level mode, air is blown from both the upper air outlet and the foot air outlet at the same time. The face mode in which air is blown out is shown. The control characteristics shown in FIGS.
No. 4 ROM 54b. Further, the defroster mode in which hot air is mainly blown toward the windshield 29 is not determined by TAO, but is set by turning on the defroster switch 48 provided on the air conditioning panel 49.

Then, in step S9, the electromagnetic clutch 22 is disengaged (ON) based on the characteristic diagram of FIG. 6 or the state of the air conditioning (A / C) switch (not shown) of the air conditioning control panel 49. / OFF) control is performed to intermittently operate the compressor 17. Here, FIG. 6 shows the relationship between the post-evaporation temperature Te and ON / OFF of the electromagnetic clutch 22. The ROM 54b of the microcomputer 54 is previously shown.
Remembered in.

Next, in step S10, the RAM 54c
The target opening degree SW of the air mix door 17 is calculated based on the various data stored in the above and the following mathematical formula 2 stored in the ROM 54b.

[0027]

## EQU2 ## SW = {(TAO-Te) / (Tw-Te)}
× 100 (%) Next, in step S11, the target air mix door opening degree SW calculated in step 10 so that the mode determined in steps S6 to S9 is achieved.
Drive circuits 7c, 10a, 22a, 23
Blower motor 1 via c, 30c, 31c, 32c
0, servomotors 7b, 23b, 30b, 31b, 32
b, output a control signal to the electromagnetic clutch 22.

Then, in step S12, step S1
It is determined whether or not the predetermined cycle time t has elapsed after executing the process of No. 1, and the next process is not performed until the result of this determination is Yes, and if Yes is determined, the process of step S2 is performed again. Execute the process. On the other hand, when it is determined in step S5 that the pre-starting operation is in progress based on the pre-starting operation signal SP, the process proceeds to step S13, in which it is determined whether or not the occupant has boarded by the signal from the door switch 55. . That is, when the open or close signal is input from the door switch 55 after the execution of the air conditioning control program, it is determined that the occupant has boarded.

Next, in step S14, the set temperature T
It is determined whether the difference between the set and the indoor temperature Tr (Tset-Tr) is smaller than the predetermined value A. Where | Tset
When the relationship −Tr | ≦ A is satisfied, that is, when it is determined that the indoor temperature Tr is substantially at the set temperature Tset, the process proceeds to step S16, the pre-start operation signal SP is cleared, and the process proceeds to step S7.

On the other hand, in step S14, | Tset
If −Tr |> A is determined, the process proceeds to step S15,
The control characteristic of the applied voltage of the blower motor 10 is set to the characteristic of FIG. 3b, and the blower motor 10 is supplied with the voltage Ve ′ shown in FIG.
It is calculated based on AO and applied to the motor 10. As shown in FIG. 3, since the voltage Ve 'of the b characteristic is set to be larger than the voltage Ve of the a characteristic, the amount of air blown by the blower 8 is large.

By controlling as described above, the difference between the preset temperature Tset preset by the occupant and the room temperature Tr (Tset-T) when the pre-starting device 50 is operating.
When r) is larger than the predetermined value A, the blower motor 10 is rotated at a high speed by the voltage Ve 'based on the characteristic b of FIG. 3 so that the room temperature Tr can quickly reach the set temperature Tset, and thus the room temperature Tr is set. Can be set to the warm feeling priority mode for early air conditioning.

On the other hand, even when the pre-starting device 50 is operating, the difference (Tset) between the set temperature Tset and the room temperature Tr.
When −Tr) becomes smaller than the predetermined value A, the normal control mode according to the characteristic a in FIG. 3 is set to the temperature / sound sensation compatible mode, and extra power consumption by the blower motor 10 can be prevented. Here, the sound-sensing mode refers to a mode in which reduction of the air conditioner operating noise (mainly the operating noise of the blower 8) is taken into consideration.

When an occupant gets on the board, the temperature sensation priority mode based on the characteristic b is immediately switched to the temperature sensation / sound sensation compatible mode based on the characteristic a to eliminate the discomfort caused by blowing noise. As can be understood from the above description, in the above-described embodiment, step S5 constitutes the pre-starting state determination means for the engine E, and step S13 constitutes the passenger presence / absence determination means. Step S1
4 constitutes a temperature difference determination means, and step S1
Reference numeral 5 constitutes a changing means for changing the air flow rate control characteristic of the air blowing means 8 to the characteristic b at the time of pre-start in which the air flow rate is larger than the characteristic a at the normal time when the engine E is in the pre-start state. Further, step S16 is performed when an occupant boarded in the pre-start state of the engine E or when the temperature difference (Ts
When the (et-Tr) becomes smaller than the predetermined value A, the control means sets the air flow rate control characteristic of the air blowing means 8 to the normal characteristic a.

In the above-described embodiment, the case where only the blow control characteristics are switched at the time of pre-starting has been described, but other controls may be combined. That is, the present invention has one purpose to quickly bring the indoor temperature Tr closer to the set temperature Tset at the time of pre-starting, and thus the change of the blowout port mode or the suction port mode may be combined with the air blowing control.

More specifically, at the start of heating in winter, the indoor temperature may be compared with the outside air temperature, and the suction port with the higher temperature may be selected. For example, when the room temperature is higher than the outside air temperature, in addition to the switching of the air blowing control characteristics described above, a control for forcibly setting the suction port mode to the inside air suction mode is combined to further speed up the rise of the room temperature. Good. On the contrary, at the start of cooling in the summer, the indoor temperature may be compared with the outside air temperature and the suction port with the lower temperature may be selected. For example, when the outside air temperature is lower than the room temperature, the suction port mode may be forcibly set to the outside air suction mode so that the decrease in the room temperature is further accelerated. Alternatively, the outlet mode may be forcibly set to the face mode at the start of heating in the winter to improve the circulation of the blown air flow in the room and further increase the temperature of the room.

Further, the pre-starting device 50 is not limited to the one using the wireless remote controller 52 described above, but a timer means as disclosed in, for example, JP-A-62-8814 may be used. The present invention can be applied to various configurations such as a configuration in which the engine E is automatically pre-started by the timer output when the scheduled boarding time set by the occupant is reached. In short, any device may be used as long as it can obtain the pre-starting operation signal SP.

In addition to the door switch 55, a seat occupancy switch or the like may be used alone or in combination with the door switch as the passenger detection means. In short, a signal is output in conjunction with the passenger's boarding operation. Anything that outputs can be used.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a device of the present invention.

FIG. 2 is a flow chart showing the operation of an embodiment of the device of the present invention.

FIG. 3 is a characteristic diagram of air flow rate control in one embodiment of the device of the present invention.

FIG. 4 is a characteristic diagram of suction port control in one embodiment of the device of the present invention.

FIG. 5 is a characteristic diagram of outlet control in one embodiment of the device of the present invention.

FIG. 6 is a characteristic diagram of compressor control in one embodiment of the device of the present invention.

[Explanation of symbols]

 8 Blower (air-conditioning ventilation means) 10 Motor 50 Pre-starting device 51 Pre-starting control circuit section 52 Remote control device 53 Starter control circuit S Starter E engine 54 Microcomputer (air conditioning control device) 55 Door switch (boarding detection means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Ito 1-1 Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (72) Inventor Yuji Honda 1-1 Showa-cho, Kariya city, Aichi Nidec Incorporated (72) Inventor Katsuhiko Samukawa 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (4)

[Claims] 1. An air conditioning control device for use in a vehicle having a pre-starting device capable of starting the vehicle running engine before the passenger is boarded in the vehicle, wherein the vehicle running engine is pre-started by the pre-starting device. And a determination means for determining whether or not the vehicle is in a state, and when the determination means determines that the vehicle running engine is in the pre-start state, the air flow rate control characteristic of the air conditioning air flow means is set to be a ventilation rate based on a normal state. And an air-conditioning control device for a vehicle. 2. An air conditioning control device for use in a vehicle having a pre-starting device capable of starting the vehicle running engine before the passenger is boarded in the vehicle, wherein the vehicle running engine is pre-started by the pre-starting device. And a pre-starting determination means for determining whether or not the vehicle is in a state, and when the pre-starting determination means determines that the vehicle traveling engine is in the pre-starting state, the air flow rate control characteristic of the air conditioning blower means Change means that changes to the characteristics at the time of pre-start that has more air flow than the characteristics, and the temperature difference that determines whether the temperature difference between the target temperature for the vehicle interior temperature control and the actual vehicle interior temperature is within a predetermined value. When the temperature difference is determined to be within a predetermined value by the determination means and the temperature difference determination means, the air flow rate control characteristic of the air conditioning air blow means even when the vehicle running engine is in the pre-start state. At normal time Vehicle air conditioning control device, characterized in that it comprises a control means for setting the characteristic 3. An air conditioning control device for use in a vehicle having a pre-starting device capable of starting the vehicle running engine before the passenger is boarded in the vehicle, wherein the vehicle running engine is pre-started by the pre-starting device. And a pre-starting determination means for determining whether or not the vehicle is in a state, and when the pre-starting determination means determines that the vehicle traveling engine is in the pre-starting state, the air flow rate control characteristic of the air conditioning blower means Change means for changing to the characteristics at the time of pre-start that has more air flow than the characteristics, boarding judgment means for judging whether or not an occupant is on the vehicle, and this boarding judgment means is judged to be the occupant's boarding state And a control means for setting the air flow rate control characteristic of the air conditioning air blow means to the characteristic at the normal time. 4. An air conditioning control device for use in a vehicle having a pre-starting device capable of starting the vehicle running engine before the passenger is boarded in the vehicle, wherein the vehicle running engine is pre-started by the pre-starting device. A pre-starting determination means for determining whether or not the vehicle is in a state, and a temperature difference determination means for determining whether or not a temperature difference between a target temperature for vehicle compartment temperature control and an actual vehicle compartment temperature is within a predetermined value. The boarding determination means for determining whether or not an occupant is boarding the vehicle, and when the boarding determination means determines that the occupant is in the boarding state, the air flow rate control characteristic of the air conditioning ventilation means is set to the normal state. When the boarding determination means determines that the occupant is in a non-boarding state, and the temperature difference determination means determines that the temperature difference is within a predetermined value, the vehicle travels. Engine for advance Even in the dynamic state, the control means for setting the air flow rate control characteristic of the air conditioning blower means to the characteristic at the normal time, and the pre-starting determination means have determined that the vehicle running engine is in the pre-starting state. At this time, when the boarding determination means determines that the occupant is in the non-boarding state, and when the temperature difference determination means determines that the temperature difference is larger than the predetermined value, the ventilation of the air conditioning blowing means is performed. A vehicle air conditioning control device comprising: a changing unit that changes the air flow rate control characteristic to a characteristic at the time of pre-starting in which the air flow rate is larger than that at the time of normal operation.