Air conditioner

In a rotary door of a vehicular air conditioner, an outer peripheral portion closes a defroster blowing opening and another outer peripheral portion closes a foot blowing opening in a face mode. A first door opening communicates with an inlet opening and a second door opening communicates with a face blowing opening. A cross-sectional area of a flow path through which the airflow passes through the inlet opening and the first door opening is equal to a cross-sectional area of a flow path through which the airflow passes through the face blowing opening and the second door opening.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C. 371 of International Application No. PCT/JP2015/005709 filed on Nov. 17, 2015 and published in Japanese as WO 2016/084332 A1 on Jun. 2, 2016. This application is based on and claims the benefit of priority from Japanese Patent Applications No. 2014-240159 filed on Nov. 27, 2014, and No. 2015-190125 filed on Sep. 28, 2015. The entire disclosures of all of the above applications are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an air conditioner provided with a rotary door.

BACKGROUND ART

Conventionally, a vehicular air conditioner includes a cooling heat exchanger or the like installed in an air conditioning case to regulate a temperature of air blown from an air blower, and a rotary door to switch blow modes in which temperature-regulated air is blown into a compartment (see, for example, Patent Document 1).

The rotary door is stored in the air conditioning case, and includes first and second outer peripheral portions which extend in a circumferential direction centered at a rotation shaft while being arranged side by side in the circumferential direction at an interval. First and second door openings are provided in respective spaces between the first and second outer peripheral portions. The rotary door is configured in such a manner that the first and second outer peripheral portions and the first and second door openings rotate with a rotation of the rotation shaft.

Multiple blowing openings are provided to the air conditioning case along an outer periphery of the rotary door about the rotation shaft. The multiple blowing openings include a defroster blowing opening, a foot blowing opening, and a face blowing opening.

When one of the first and second door openings communicates with one of the multiple blowing openings, an airflow flowing from another of the first and second door openings is blown into a compartment through the one door opening and the one blowing opening communicating with each other.

Accordingly, when the rotary door rotates, the blowing opening which communicates with the door opening is switched. That is, the blowing opening from which an airflow is blown into the compartment switches from one to another among the multiple blowing openings. Accordingly, the blow modes can be switched. By using the rotary door configured as above, a physical size of the air conditioning case and a pressure loss of an airflow can be reduced in comparison with a case where doors are provided to the respective blowing openings.

The vehicular air conditioner of Patent Document 1 using the rotary door to switch the blow modes in the manner described above is capable of reducing a physical size of the air conditioning case and a pressure loss of an airflow. Hence, a level of noise generated when an airflow passes through the air conditioning case can be lowered over a broad range of frequency.

In practice, however, noise at a predetermined frequency, such as wind noise generated when an air flow passes through the cooling heat exchanger and noise generated at the air blower, propagates to the compartment without being attenuated in the air conditioning case in some cases. In other words, a noise level can be lowered over a broad range of frequency by the rotary door whereas noise at a predetermined frequency may possibly become obvious in comparison with noise at other frequencies, in which case noise at the predetermined frequency may give an occupant in the compartment a feeling of strangeness.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: JP 2013-023120 A

SUMMARY

In view of the foregoing points, an object of the present disclosure is to provide an air conditioner capable of lowering a noise level.

According to a first aspect of the present disclosure, an air conditioner includes an air blower generating an airflow, a rotary door, an air conditioner case, a door space, a first controller, a second controller, an adjusting door, a detector and a third controller. The rotary door includes: a plurality of outer peripheral portions extending in a circumferential direction centered at a shaft center of a rotation shaft which is rotatable, and being arranged side by side in the circumferential direction; first and second side walls disposed, respectively, on a first side and a second side of the plurality of outer peripheral portions in an axial direction of the rotation shaft; and a plurality of door openings provided between the plurality of outer peripheral portions. The plurality of outer peripheral portions, the first and second side walls, and the plurality of door openings rotate simultaneously in accordance with rotation of the rotation shaft. The air conditioner case stores the rotary door and includes an air flow path where the airflow flows, and a case peripheral wall portion. The case peripheral wall portion includes an inlet opening communicating with the air flow path, and a plurality of blowing openings communicating with a compartment. The inlet opening and the plurality of blowing openings are located on an outer side of the rotary door in a radial direction centered at the shaft center. The door space is provided inside the rotary door in the air conditioner case and surrounded by the plurality of outer peripheral portions, the first and second side walls, and the case peripheral wall portion. When a first door opening of the plurality of door openings communicates with the inlet opening, and when a second door opening of the plurality of door openings communicates with a first blowing opening of the plurality of blowing openings, an airflow from the air flow path is blown into the compartment through the inlet opening, the first door opening, the door space, the second door opening, and the first blowing opening. The first controller controls the rotary door to allow the second door opening to communicate with the first blowing opening. The second controller controls the air blower to blow a predetermined volume of blowing air. The adjusting door adjusts at least one of a first area and a second area. The first area is defined as a cross-sectional area of a flow path through which the airflow passes from the inlet opening to the first door opening, and the second area is defined as a cross-sectional area of a flow path through which the airflow passes from the second door opening to the first blowing opening. The detector detects a level of noise generated when the first controller controls the rotary door and when the second controller controls the air blower. The third controller controls the adjusting door to reduce a difference between the first area and the second area when a detection value of the detector is determined to be equal or larger than a predetermined value.

Owing to the configuration as above, a noise level can be lowered by controlling the adjusting door to reduce a difference between the first area and the second area when the noise level is at or above the predetermined value.

According to a second aspect of the present disclosure, an air conditioner includes an air blower generating an airflow, a rotary door, an air conditioner case, a door space, a first decider, a second decider, a first controller, a second controller, a determiner, an adjusting door and a third controller. The rotary door includes: a plurality of outer peripheral portions extending in a circumferential direction centered at a shaft center of a rotation shaft which is rotatable, and being arranged side by side in the circumferential direction; first and second side walls disposed, respectively, on a first side and a second side of the plurality of outer peripheral portions in an axial direction of the rotation shaft; and a plurality of door openings provided between the plurality of outer peripheral portions. The plurality of outer peripheral portions, the first and second side walls, and the plurality of door openings rotate simultaneously in accordance with rotation of the rotation shaft. The air conditioner case stores the rotary door and includes an air flow path where the airflow flows, and a case peripheral wall portion. The case peripheral wall portion includes an inlet opening communicating with the air flow path, and a plurality of blowing openings communicating with a compartment. The inlet opening and the plurality of blowing openings are located on an outer side of the rotary door in a radial direction centered at the shaft center. The door space is provided inside the rotary door in the air conditioner case and surrounded by the plurality of outer peripheral portions, the first and second side walls, and the case peripheral wall portion. When a first door opening of the plurality of door openings communicates with the inlet opening, and when a second door opening of the plurality of door openings communicates with a first blowing opening of the plurality of blowing openings, an airflow from the air flow path is blown into the compartment through the inlet opening, the first door opening, the door space, the second door opening, and the first blowing opening. The first decider decides one of the plurality of blowing openings as the first blowing opening from which the airflow is blown out. The second decider decides a volume of blowing air to be generated by the air blower. The first controller controls the rotary door to allow the second door opening to communicate with the first blowing opening decided by the first decider. The second controller controls the air blower to blow the volume of blowing air decided by the second decider. The determiner determines whether a noise level estimated according to the volume of blowing air decided by the second decider and the first blowing opening decided by the first decider is at or above a predetermined value, before the controls are performed by the first controller and the second controller. The adjusting door adjusts at least one of a first area and a second area. The first area is defined as a cross-sectional area of a flow path through which the airflow passes from the inlet opening to the first door opening, and the second area is defined as a cross-sectional area of a flow path through which the airflow passes from the second door opening to the first blowing opening. The third controller controls the adjusting door to reduce a difference between the first area and the second area at the time of the controls performed by the first controller and the second controller, when the determiner determines that the noise level estimated is at or above the predetermined value.

Owing to the configuration as above, a noise level can be lowered by controlling the adjusting door to reduce a difference between the first area and the second area when controls by the first controller and the second controller are performed.

According to a third aspect of the present disclosure, an air conditioner includes a rotary door, an air conditioner case and a door space. The rotary door includes: a plurality of outer peripheral portions extending in a circumferential direction centered at a shaft center of a rotation shaft which is rotatable, and being arranged side by side in the circumferential direction; first and second side walls disposed, respectively on a first side and a second side of the plurality of outer peripheral portions in an axial direction of the rotation shaft; and a plurality of door openings provided between the plurality of outer peripheral portions. The plurality of outer peripheral portions, the first and second side walls, and the plurality of door openings rotate simultaneously in accordance with rotation of the rotation shaft. The air conditioner case stores the rotary door and includes an air flow path where an airflow flows, and a case peripheral wall portion. The case peripheral wall portion includes an inlet opening communicating with the air flow path, and a plurality of blowing openings communicating with a compartment. The inlet opening and the plurality of blowing openings are located on an outer side of the rotary door in a radial direction centered at the shaft center. The door space is provided inside the rotary door in the air conditioner case and surrounded by the plurality of outer peripheral portions, the first and second side walls, and the case peripheral wall portion. When a first door opening of the plurality of door openings communicates with the inlet opening, and when a second door opening of the plurality of door openings communicates with a first blowing opening of the plurality of blowing openings, an airflow from the air flow path is blown into the compartment through the inlet opening, the first door opening, the door space, the second door opening, and the first blowing opening. A cross-sectional area of a flow path through which the airflow passes from the inlet opening to the first door opening is defined as a first area, and a cross-sectional area of a flow path through which the airflow passes from the second opening to the first blowing opening is defined as a second area. The first area and the second area are equal to each other.

Owing to the configuration as above, because the first area and the second area are equal to each other, air expands in the door space when an airflow flows into the door space from the inlet opening and pulsation of the airflow can be reduced. Hence, an air conditioner capable of lowering a noise level by using the rotary door can be provided.

The term, “a cross-sectional area of a flow path”, referred to herein means an area of a flow path in cross section orthogonal to an air flowing direction in an air flow path where an airflow flows. For example, the first area is an area of a flow path in cross section orthogonal to an air flowing direction in an air flow path formed when an airflow passes through the inlet opening and the first door opening. The second area is an area of a flow path in cross section orthogonal to an air flowing direction in an air flow path formed when an airflow passes through the second door opening and the first blowing opening.

DESCRIPTION OF EMBODIMENTS

Hereinafter, multiple embodiments for implementing the present invention will be described referring to drawings. In the respective embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.

First Embodiment

FIG. 1is a view showing a schematic configuration of a vehicular air conditioner1. InFIG. 1, respective arrows pointing upward, downward, frontward, and rearward specify directions when the vehicular air conditioner1is installed to a vehicle. The upward arrow specifies an upper side in a vertical direction, the downward arrow specifies a lower side in the vertical direction, the frontward arrow specifies a front side in a vehicle moving direction, and the rearward arrow specifies a rear side in the vehicle moving direction.

The vehicular air conditioner1includes an air conditioning unit10. The air conditioning unit10includes a case11(air conditioning case), a cooling heat exchanger12, a heating heat exchanger13, an air mixing door14, and a rotary door15. An air introduction port11ais provided to the front side of the case11in the vehicle moving direction. The air introduction port11aopens at one side of the case in a vehicular width direction. Air blown from an air blowing unit (air blower)20(seeFIG. 2) is introduced to the air introduction port11a. The air blowing unit20is provided on one side of the air conditioning unit10in the vehicular width direction (i.e. on a front passenger's seat side).

The cooling heat exchanger12is installed on the rear side of the air introduction port11aof the case11in the vehicle moving direction. The cooling heat exchanger12together with a compressor, a condenser, and an expansion valve forms a known refrigeration cycle device in which a refrigerant circulates, and cools air introduced into the air introduction port11aby letting the refrigerant evaporate.

The heating heat exchanger13is disposed on the rear side of the cooling heat exchanger12in the vehicle moving direction in the case11, and heats cold air blown out from the cooling heat exchanger12with an engine coolant (hot water). A hot air passage16is formed on the rear side of the heating heat exchanger13in the vehicle moving direction within the case11and introduces hot air blown out from the heating heat exchanger13toward an inlet opening30aof the rotary door15.

A cold air bypass passage17is formed between the cooling heat exchanger12and the heating heat exchanger13within the case11. The cold air bypass passage17is a passage through which cold air from the cooling heat exchanger12is introduced toward an inlet opening30bof the rotary door15by bypassing the heating heat exchanger13. The inlet opening30aand30bare located on the upper side of the heating heat exchanger13in the vertical direction.

The air mixing door14is provided near the inlet openings30aand30babove the heating heat exchanger13. The air mixing door14is supported on a rotation shaft40(indicated by a chain line ofFIG. 1) in a rotatable manner about the rotation shaft40. The air mixing door14is formed in an arc shape about the rotation shaft40in cross section.FIG. 1shows the rotation shaft40when seen through from inside the rotary door15.

The air mixing door14changes a ratio of an opening area of the cold air bypass passage17and an opening area of the hot air passage16according to its own position. The air mixing door14thus changes a ratio of an opening area of the inlet opening30aand an opening area of the inlet opening30b. Hence, the air mixing door14is capable of adjusting a temperature of air to be blown into the compartment by adjusting a ratio of a volume of air flowing through the cold air bypass passage17as is indicated by an arrow a and a volume of air flowing through the hot air passage16as is indicated by an arrow b.

The air mixing door14is driven by an electric motor or manually.FIG. 1shows the air mixing door14in a maximum cool state fully closing the hot air passage16and fully opening the cold air bypass passage17.

The rotary door15forms a mode switching door which switches blow modes and is disposed on the upper side of the heating heat exchanger13in the vertical direction within the case11. The rotary door15is supported on the rotation shaft40in a rotatable manner with respect to the case11. The rotary door15is driven, for example, by an electric motor or manually.

A case peripheral wall portion50is provided on an outer side of the rotary door15in a direction of a radius within the case11. The case peripheral wall portion50is formed in an arc shape about the rotation shaft40in cross section. The case peripheral wall portion50is provided with a defroster blowing opening51b, a face blowing opening51c, and a foot blowing opening51d. The defroster blowing opening51b, the face blowing opening51cand the foot blowing opening51dare hereinafter referred to collectively as the blowing openings51b,51c, and51d. The blowing openings51b,51c, and51dare aligned side by side in a direction of a circumference centered at a shaft center S of the rotation shaft40. Hereinafter, the direction of the circumference centered at the shaft center S of the rotation shaft40is referred to simply as the circumferential direction.

In the present embodiment, the blowing openings51b,51c, and51dare located on the upper side of the rotary door15in the vertical direction. The face blowing opening51cis located next to the defroster blowing opening51bon a first side in the circumferential direction. The foot blowing opening51dis located next to the face blowing opening51con the first side in the circumferential direction.

The face blowing opening51cis a blowing opening from which air-conditioning air is blown out toward an upper half of an occupant in the compartment. The foot blowing opening51dis a blowing opening from which air-conditioning air is blown out toward a lower half of the occupant. The defroster blowing opening51bis a blowing opening from which air-conditioning air is blown out toward an inner surface of a glass window in the compartment.

The case peripheral wall portion50is provided with the inlet openings30aand30b. The inlet openings30aand30bare located on the lower side of the rotary door15in the vertical direction. The inlet opening30acommunicates with the hot air passage16. Hot air from the hot air passage16thus blows out from the inlet opening30ato the rotary door15. The inlet opening30bcommunicates with the cold air bypass passage17. Cold air from the cold air bypass passage17thus blows out from the inlet opening30bto the rotary door15. The rotary door15allows the hot air that blows out from the inlet opening30aand cold air that blows out from the inlet opening30bto blow to any one of the blowing openings51b,51c, and51d.

A specific structure of the rotary door15of the present embodiment will now be described with reference toFIG. 1andFIG. 3.FIG. 3is a perspective view of the rotary door15.FIG. 1is a cross section orthogonal to an axial direction of the rotary door15.

As are shown inFIG. 1andFIG. 3, the rotary door15includes door side walls60aand60b(only the door side wall60ais shown inFIG. 1), outer peripheral portions61,62, and63, and door openings64,65,66.

The door side walls60aand60bare formed in a circular plate shape and disposed at an interval, respectively, on a first side and a second side in an axial direction of the rotation shaft40. The axial direction of the rotation shaft40coincides with the vehicular width direction (a direction perpendicular to a sheet surface ofFIG. 1). The rotation shaft40is provided to each of the door side walls60aand60b. The rotation shafts40are provided to protrude outward (that is, in the vehicular width direction) from the corresponding door side walls60aand60b.

The respective outer peripheral portions61,62, and63shown inFIG. 1andFIG. 3are provided between the door side walls60aand60band formed in a plate shape extending in the circumferential direction about the rotation shaft40. In short, the outer peripheral portions61,62, and63are formed in an arc shape about the rotation shaft40in cross section.

The outer peripheral portions61,62, and63are disposed at intervals in the circumferential direction about the shaft center S of the rotation shaft40. The outer peripheral portion62is disposed next to the outer peripheral portion61on the first side in the circumferential direction. The outer peripheral portion63is disposed next to the outer peripheral portion62on the first side in the circumferential direction.

The outer peripheral portion62of the present embodiment is provided with an air guide62ewhich guides an airflow.

The door opening64is located on the first side of the outer peripheral portion61in the circumferential direction in a space between the outer peripheral portions61and62. The door opening65is located on the first side of the outer peripheral portion62in the circumferential direction in a space between the outer peripheral portions62and63. The door opening66is located on the first side of the outer peripheral portion63in the circumferential direction in a space between the outer peripheral portions63and61.

The outer peripheral portion61includes a door base61cextending in the circumferential direction and a film61d. The film61dis provided to cover the door base61cfrom outside in the direction of a radius. The film61dis a seal member which hermetically closes a space between the case peripheral wall portion50and the door base61c. As with the outer peripheral portion61, the outer peripheral portion62includes a door base62cand a film62d. As with the outer peripheral portion61, the outer peripheral portion63includes a door base63cand a film63d.

In the present embodiment configured as above, a door space67surrounded by the case peripheral wall portion50, the door side walls60aand60b, and the outer peripheral portions61,62, and63is defined inside the rotary door15in the case11. An area of the door space67in cross section including the shaft center S of the rotation shaft40is larger than opening areas of the respective blowing openings51b,51c, and51d. The area of the door space67in cross section including the shaft center S of the rotation shaft40is larger than opening areas of the respective inlet openings30aand30b.

Multiple air guides62fare aligned side by side at intervals in the axial direction of the rotation shaft40in the rotary door15.

A specific operation of the rotary door15of the present embodiment will now be described.FIG. 4throughFIG. 8show respective operating states of the rotary door15.

In a face mode shown inFIG. 4, the outer peripheral portion61closes the defroster blowing opening51band the outer peripheral portion62closes the foot blowing opening51d.

The door opening66communicates with the inlet opening30band the door opening64communicates with the face blowing opening51c.FIG. 4shows the air mixing door14fully opening the inlet opening30band fully closing the inlet opening30a. Under conditions as above, the door opening64is formed in a direction normal to an opening cross section of the door opening66. Cold air (see an arrow c) from the cold air bypass passage17thus flows to the inlet opening30b, the door opening66, and the door space67. The cold air is blown into the compartment from the door space67through the door opening64and the face blowing opening51c.

The inlet opening30band the door opening66communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the inlet opening30band the door opening66is defined as an area A1(first area). The face blowing opening51cand the door opening64communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the face blowing opening51cand the door opening64is defined as an area B1(second area). Then, the area A1and the area B1are equal to each other.

The term, “a cross-sectional area of a flow path”, referred to in the present embodiment means an area (flow area) of a flow path in cross section orthogonal to an air flowing direction in an air flow path where an airflow flows. For example, the area A1is an area of a flow path in cross section orthogonal to an air flowing direction in an air flow path formed when an airflow passes through the inlet opening30band the door opening66. The area B1is an area of a flow path in cross section orthogonal to an air flowing direction in an air flow path formed when an airflow passes through the face blowing opening51cand the door opening64.

The area A1is determined by the door side walls60aand60b, an end63aof the outer peripheral portion63, and an end50aof the case peripheral wall portion50. The end63ais an end of the outer peripheral portion63on the first side in the circumferential direction. The end50aof the case peripheral wall portion50is an end on the first side in the circumferential direction in a portion where the inlet opening30bis provided to the case peripheral wall portion50.

The area B1is determined by the door side walls60aand60b, an end62aof the outer peripheral portion62, and an end50bof the case peripheral wall portion50. The end62ais an end of the outer peripheral portion62on the second side in the circumferential direction. The end50bof the case peripheral wall portion50is an end on the second side in the circumferential direction in a portion where the face blowing opening51cis provided to the case peripheral wall portion50.

Owing to the configuration as above, the rotary door15forms a straight silencer of an expansion type. Hence, cold air blown out from the cooling heat exchanger12enters the door space67after the cold air is squeezed at the door opening66. It should be noted that air expands in the door space67and the expanded air is squeezed at the door opening64. Because air expands in the door space67, a velocity of an airflow decreases. Pulsation of an airflow that causes noise is thus reduced.

When the rotary door15rotates clockwise, the face mode switches to a bi-level mode shown inFIG. 5. In the bi-level mode, the outer peripheral portion61closes the defroster blowing opening51band the door opening64communicates with both of the face blowing opening51cand the foot blowing opening51d. Also, the door opening66communicates with the inlet opening30b. InFIG. 5, the air mixing door14fully opens the inlet opening30band fully closes the inlet opening30a. Under conditions as above, cold air (see an arrow d) from the cold air bypass passage17flows to the inlet opening30b, the door opening66, and the door space67. A part of the cold air flowing into the door space67is blown into the compartment through the door opening64and the face blowing opening51c. In addition, a rest of the cold air flowing into the space67other than the part specified above is blown into the compartment through the door opening64and the foot blowing opening51d.

When the rotary door15further rotates clockwise, the bi-level mode switches to a foot mode shown inFIG. 6. In the foot mode, the outer peripheral portion61closes the face blowing opening51cand the door opening66slightly communicates with the defroster blowing opening51bwhile the door opening64communicates with the foot blowing opening51d. Under the conditions as above, the outer peripheral portion61faces the door opening65across the shaft center S of the rotation shaft40. InFIG. 6, the air mixing door14fully closes the inlet opening30band fully opens the inlet opening30a. The rotary door15thus forms a right-angled silencer of an expansion type.

Herein, the air mixing door14fully closes the inlet opening30band fully opens the inlet opening30a. Under conditions as above, hot air from the hot air passage16flows to the inlet opening30aand the door opening65and toward the shaft center S in the door space67. As is indicated by an arrow e, most of the hot air is blown into the compartment from the door space67through the door opening64and the foot blowing opening51d. Meanwhile, as is indicated by an arrow f, a part of the hot air flowing into the door space67from the hot air passage16is blown into the compartment through the door opening66and the defroster blowing opening51b.

The inlet opening30aand the door opening65communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the inlet opening30aand the door opening65is defined as an area A2. The defroster blowing opening51band the door opening66communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the defroster blowing opening51band the door opening66is defined as an area B2a. The foot blowing opening51dand the door opening64communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the foot blowing opening51dand the door opening64is defined as an area B2b. Then, the area A2and the area B2b(>B2a) are equal to each other and the area B2bis larger than the area B2a.

The area A2is determined by the door side walls60aand60b, an end14aof the air mixing door14, and an end50gof the case peripheral wall portion50. The end14aof the air mixing door14is an end of the air mixing door14on the second side in the circumferential direction. Herein, it is the air mixing door14that adjusts the area A2. The end50gof the case peripheral wall portion50is an end on the second side in the circumferential direction in a portion where the inlet opening30ais provided to the case peripheral wall portion50.

The area B2ais determined by the door side walls60aand60b, an end61bof the outer peripheral portion61, and an end50hof the case peripheral wall portion50. The end50his a nearest part to the end61bin a portion where the defroster blowing opening51bis provided to the case peripheral wall portion50. The end61bof the outer peripheral portion61is an end of the outer peripheral portion61on the second side in the circumferential direction.

The area B2bis determined by the door side walls60aand60band ends50dand50eof the case peripheral wall portion50. The end50dis an end on the first side in the circumferential direction in a portion where the foot blowing opening51dis provided to the case peripheral wall portion50. The end50eis an end on the second side in the circumferential direction in the portion where the foot blowing opening51dis provided to the case peripheral wall portion50.

Owing to the configuration as above, hot air blown out from the hot air passage16enters the door space67after the hot air is squeezed at the door opening65. It should be noted that air expands in the door space67and the expanded air is squeezed at the door opening64. Because air expands in the door space67, a velocity of an airflow decreases. Pulsation of an airflow that causes noise is thus reduced.

When the rotary door15further rotates clockwise, the foot mode switches to a foot-defroster mode shown inFIG. 7. In the foot-defroster mode, the outer peripheral portion61closes the face blowing opening51c, the door opening66communicates with the defroster blowing opening51b, the door opening64communicates with the foot blowing opening51d, and the door opening65communicates with the inlet opening30a. InFIG. 7, the air mixing door14fully closes the inlet opening30band fully opens the inlet opening30a.

Under conditions as above, hot air from the hot air passage16flows to the inlet opening30aand the door opening65and toward the shaft center S in the door space67. As is indicated by an arrow g, a part of the hot air flowing as above is blown into the compartment from the door space67through the door opening64and the foot blowing opening51d. Meanwhile, as is indicated by an arrow h, a rest of the hot air flowing from the hot air passage16into the door space67other than the part specified above is blown into the compartment through the door opening66and the defroster blowing opening51b.

The inlet opening30aand the door opening65communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the inlet opening30aand the door opening65is defined as an area A3. The defroster blowing opening51band the door opening66communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the defroster blowing opening51band the door opening66is defined as an area B3a. The foot blowing opening51dand the door opening64communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the foot blowing opening51dand the door opening64is defined as an area B3b. Further, let an area B3(=B3a+B3b) be a sum of the area B3aand the area B3b. Then, the area B3and the area A3are equal to each other.

The area A3is determined by the door side walls60aand60b, the end14aof the air mixing door14, and the end62aof the outer peripheral portion62. The end14aof the air mixing door14is the end of the air mixing door14on the second side in the circumferential direction. Herein, it is the air mixing door14that adjusts the area A3. The end62aof the outer peripheral portion62is the end of the outer peripheral portion62on the second side in the circumferential direction.

The area B3ais determined by the door side walls60aand60b, the end61bof the outer peripheral portion61, and an end50fof the case peripheral wall portion50. The end50fis an end on the second side in the circumferential direction in a portion where the defroster blowing opening51bis provided to the case peripheral wall portion50. The end61bof the outer peripheral portion61is the end of the outer peripheral portion61on the second side in the circumferential direction.

The area B3bis determined by the door side walls60aand60b, an end61aof the outer peripheral portion61, and the end50dof the case peripheral wall portion50. The end61aof the outer peripheral portion61is an end of the outer peripheral portion61on the first side in the circumferential direction. The end50dis the end on the first side in the circumferential direction in the portion where the foot blowing opening51dis provided to the case peripheral wall portion50.

Owing to the configuration as above, hot air blown out from the hot air passage16enters the door space67after the hot air is squeezed at the door opening65. It should be noted that air expands in the door space67and the expanded air is squeezed at the door opening64. Because air expands in the door space67, a velocity of an airflow decreases. Pulsation of an airflow that causes noise is thus reduced.

When the rotary door15further rotates clockwise, the foot-defroster mode switches to a defroster mode shown inFIG. 8. In the defroster mode, the outer peripheral portion61closes both of the face blowing opening51cand the foot blowing opening51d. Further, the door opening66communicates with the defroster blowing opening51band both of the door openings65and64communicate with the inlet opening30a. InFIG. 8, the air mixing door14fully closes the inlet opening30band fully opens the inlet opening30a.

Under conditions as above, hot air from the hot air passage16is blown into the compartment through the inlet opening30a, the door openings65and64, the door space67, the door opening66, and the defroster blowing opening51b.

The inlet opening30aand the respective door openings65and64communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the inlet opening30aand both the door openings65and64is defined as an area A4. The defroster blowing opening51band the door opening66communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the defroster blowing opening51band the door opening66is defined as an area B4. Then, the area A4and the area B4are equal to each other.

The area A4is determined by the door side walls60aand60b, the end14aof the air mixing door14, and the end50gof the case peripheral wall portion50. The end14aof the air mixing door14is the end of the air mixing door14on the second side in the circumferential direction. The end50gof the case peripheral wall portion50is the end on the second side in the circumferential direction in the portion where the inlet opening30ais provided to the case peripheral wall portion50.

The area B4is determined by the door side walls60aand60band the end50fand an end51hof the case peripheral wall portion50. The end50fis the end on the second side in the circumferential direction in the portion where the defroster blowing opening51bis provided to the case peripheral wall portion50. The end51his an end on the first side in the circumferential direction in the portion where the defroster blowing opening51bis provided to the case peripheral wall portion50.

Owing to the configuration as above, hot air blown out from the hot passage16enters the door space67after the hot air is squeezed at the respective door openings65and64. It should be noted that air expands in the door space67and the expanded air is squeezed at the door opening64. Because air expands in the door space67, a velocity of an airflow decreases. Pulsation of an airflow that causes noise is thus reduced.

According to the embodiment described above, in the face mode, the area A1which is a cross-sectional area of a flow path when an airflow passes through the inlet opening30band the door opening66is equal to the area B1which is a cross-sectional area of a flow path when an airflow passes through the face blowing opening51cand the door opening64. Hence, pulsation of an airflow can be reduced because air expands in the door space67when the airflow flows into the door space67from the inlet opening30b.

In the foot mode, the area A2which is a cross-sectional area of a flow path when an airflow passes through the inlet opening30band the door opening65is equal to the area B2bwhich is a cross-sectional area of a flow path when an airflow passes through the foot blowing opening51dand the door opening64.

In the foot-defroster mode, the area A3which is a cross-sectional area of a flow path when an airflow passes through the inlet opening30aand the door opening65is equal to the area B3(=B3a+B3b) which is a cross-sectional area of a flow path when an airflow passes through both of the blowing openings51band51dand both of the door openings66and64.

In the defroster mode, the area A4which is a cross-sectional area of a flow path when an airflow passes through the inlet opening30aand both of the door openings65and64is equal to the area B4which is a cross-sectional area of a flow path when an airflow passes through the defroster blowing opening51band the door opening66.

Consequently, in the foot mode, the foot-defroster mode, and the defroster mode, pulsation of an airflow can be reduced because air expands in the door space67when the airflow flows into the door space67from the inlet opening30a. Hence, a level of noise at a target frequency can be lowered by designing an attenuation ratio of the rotary door15. The vehicular air conditioner1capable of lowering a noise level by using the rotary door15can be thus provided.

In the present embodiment, the outer peripheral portions61,62, and63are provided in such a manner that the door opening65faces the outer peripheral portion61across the shaft center S of the rotation shaft40in the foot-defroster mode. An inner side of the outer peripheral portion61in the direction of the radius is formed in an arc shape about the rotation shaft S of the rotation shaft40.

Hence, pulsation of hot air introduced from the hot air passage16toward the shaft center S in the door space67through the door opening65is reflected toward the shaft center S in the door space67on the inner side of the outer peripheral portion61in the direction of the radius. Pulsation of hot air reflected in the manner as above and pulsation of hot air introduced from the hot air passage16toward the shaft center S in the door space67through the door opening65cancel each other out. The noise level in the door space67can be thus lowered further.

A noise reduction effect by the rotary door15of the present embodiment will now be described with reference toFIG. 9throughFIG. 13. In the following description, the term, “a dimension (mm)”, is also used as an equivalent to the area.

FIG. 9,FIG. 10, andFIG. 11show reduction effects on noise at a target frequency of 800 Hz in the face mode. An abscissa is used for the area B1(dimension B1) and an ordinate is used for a noise attenuation amount, an increase amount in airflow noise, and a noise reduction effect. A noise attenuation amount is a noise attenuation amount due to expansion of air in the rotary door15. An increase amount in airflow noise is an increase amount in a level of noise generated when air passes through the door openings64,65, and66of the rotary door15, that is, a value indicating a difference between a noise level and a predetermined reference value. A noise reduction effect is a noise reduction effect by the rotary door15and determined by a difference between a noise attenuation amount and an increase amount in airflow noise.

FIG. 9shows a noise reduction effect when the area A1(dimension A1) is 20 mm. When the area B1is 20 mm, a difference between an attenuation amount and an increase amount in airflow noise becomes larger than when the area B1is 10 mm or 40 mm. Hence, a noise reduction effect is most significant when the area A1is 20 mm.

FIG. 10shows a noise reduction effect when the area A1is 40 mm. When the area B1is 40 mm, a difference between an attenuation amount and an increase amount in airflow noise becomes larger than when the area B1is 20 mm or 60 mm. Hence, a noise reduction effect is most significant when the area A1is 40 mm.

FIG. 11shows a noise reduction effect when the area A1is 60 mm. When the area B1is 60 mm, a difference between an attenuation amount and an increase amount in airflow noise becomes larger than when the area B1is 40 mm or 80 mm. Hence, a noise reduction effect is most significant when the area A1is 60 mm.

FIG. 12shows graphs Ga and Gb using an abscissa for a frequency of noise and an ordinate for noise reduction effects when the areas A1and B1are 40 mm or 20 mm. The graph Ga is a graph when the area A1is 40 mm and the area B1is 20 mm and the graph Gb is a graph when the area A1is 20 mm and the area B1is 20 mm.

It is understood from the above descriptions that a noise reduction effect is most significant when the area A1and the area B1are equal to each other.

FIG. 13shows a graph using an abscissa for a ⅓ octave frequency and an ordinate for a noise level. A thick line ofFIG. 13represents a noise level when the area A1and the area B1are made to be equal to each other by using the rotary door15of the first embodiment of the present disclosure. A thin line ofFIG. 13represents a noise level when a rotary door of a comparative example is used and the area A1and the area B1are not equal to each other. It is understood fromFIG. 13that a noise reduction effect becomes more significant when the area A1and the area B1are made to be equal to each other by using the rotary door15.

In the present embodiment, a level of noise at a target frequency is lowered by designing an attenuation ratio of the rotary door15in the manner described above. Hence, restrictions imposed by cost and manufacturing reasons can be easily lifted. In addition, a size can be reduced in comparison with a case where a silencer is formed separately from the rotary door15.

Second Embodiment

A second embodiment will describe a case where a sound deadening material is provided to outer peripheral portions61,62, and63of a rotary door15of the second embodiment.

FIG. 14is a cross section of the rotary door15of the present embodiment.

A sound deadening material70ais additionally provided to an inner side of the outer peripheral portion61of the rotary door15of the present embodiment in a direction of a radius about a shaft center S of a rotation shaft40. A film of the sound deadening material70ais provided to conform to a door base61con the inner side in the direction of the radius. A sound deadening material70bis additionally provided to an inner side of the outer peripheral portion62of the rotary door15in the direction of the radius. A film of the sound deadening material70bis provided to conform to a door base62con the inner side in the direction of the radius. A sound deadening material70cis additionally provided to an inner side of the outer peripheral portion63of the rotary door15in the direction of the radius. A film of the sound deadening material70cis provided to conform to a door base63con the inner side in the direction of the radius.

In the present embodiment, the sound deadening materials70a,70b, and70cmay be a sound absorbing member, for example, elastomer, which exerts a silencing effect.

According to the present embodiment as described above, because the sound deadening materials70a,70b, and70care provided to the rotary door15, noise at a frequency other than a target frequency set by designing an attenuation ratio in the first embodiment above can be reduced, too. Hence, the configuration as above is capable of reducing noise at frequencies at which a sound deadening effect cannot be exerted by designing an attenuation ratio of the rotary door15.

Third Embodiment

A third embodiment will describe a case where the counterpart of the first embodiment above is additionally provided with an adjusting door80which adjusts a cross-sectional area of a flow path at one of the blowing openings51b,51c, and51dfrom which air blows out and another adjusting door81which adjusts a cross-sectional area of a flow path at one of the inlet openings30aand30binto which air flows.

FIG. 15is a view showing a sectional configuration of an air conditioning unit10of a vehicular air conditioner1of the present embodiment.FIG. 15shows a case where the adjusting doors80and81are additionally provided to the configuration ofFIG. 1. InFIG. 15, like components are labeled with like reference numerals with respect toFIG. 1and a description of such components is not repeated herein.

The respective adjusting doors80and81are disposed on an inner side of outer peripheral portions61,62, and63of a rotary door15in a direction of a radius about a rotary shaft S of a rotation shaft40. The respective adjusting doors80and81are supported on the rotation shaft40in a rotatable manner about the rotation shaft S of the rotation shaft40.

As are shown inFIG. 16AandFIG. 16B, the adjusting door80includes door side walls80aand80band an outer peripheral portion80c.

The door side walls80aand80bare formed in a fan shape and provided at an interval, respectively, on a first side and a second side in an axial direction of the rotation shaft40. The axial direction of the rotation shaft40coincides with a vehicular width direction (a direction perpendicular to a sheet surface ofFIG. 16B). The door side walls80aand80bare supported on the rotation shaft40in a rotatable manner. The outer peripheral portion80cis provided between the door side walls80aand80band formed in a plate shape extending in a direction of a circumference about the rotation shaft40. In short, the outer peripheral portion80cis formed in an arc shape about the rotation shaft40in cross section. The outer peripheral portion80cis disposed on the inner side of the outer peripheral portions61,62, and63in the direction of the radius about the rotation shaft40.

The adjusting door81includes the door side walls80aand80band the outer peripheral portion80c. The adjusting door81is formed substantially in a same manner as the adjusting door80and a description is omitted herein.

An air blowing unit20of the vehicular air conditioner1of the present embodiment includes an inside-outside air switching box32and an air blower37. The inside-outside air switching box32is disposed uppermost stream of an air introduction port11aof a case11. The inside-outside air switching box32opens and closes an inside air introduction port33and an outside air introduction port34by switching an inside-outside air switching door35. The inside-outside air switching door35is driven by a servo motor36.

The electrical air blower37blowing air toward a compartment is provided downstream of the inside-outside air switching box32. The air blower37includes a centrifugal air blower fan37adriven by a motor37b. A cooling heat exchanger12cooling blowing air is disposed downstream of the air blower37.

The cooling heat exchanger12is one of elements forming a refrigeration cycle device139and cools blowing air by letting a refrigerant under low temperature and pressure evaporate with heat absorbed from the blowing air. The refrigeration cycle device139is known and formed to circulate the refrigerant from a discharge side of a compressor140to the cooling heat exchanger12by way of a condenser141, a liquid receiver142, and an expansion valve143forming a decompression device. Outside air (cooling air) is blown to the condenser141by an electrical cooling fan141a. The cooling fan141ais driven by a motor141b.

The compressor140of the refrigeration cycle device139is driven by a running engine (not shown) via an electromagnetic clutch140a. Hence, ON and OFF states of the compressor140can be controlled by energizing or de-energizing the electromagnetic clutch140a.

An electrical configuration of the vehicular air conditioner1of the present embodiment will now be described.

An air conditioner ECU26is an electronic control unit including a known microcomputer having a CPU, a ROM, a RAM, and so on, and peripheral circuits. Computer programs for an air conditioning control are pre-installed in the ROM of the air conditioner ECU26. Hence, the air conditioner ECU26performs various computations and various types of processing by running the pre-installed computer programs.

Detection signals from a group of known air conditioning sensors100through104and various operation signals from an air conditioning operation panel110are inputted into the air conditioner ECU26.

Specific examples of a group of air conditioning sensors include but not limited to the outside air temperature sensor100detecting an outside air temperature (temperature outside a compartment) Tam, the inside air temperature sensor101detecting an inside air temperature (temperature inside the compartment) Tr, the solar radiation sensor102detecting an amount of incident solar radiation, Ts, in the compartment, the evaporator temperature sensor103disposed in an air blowing portion of the cooling heat exchanger12and detecting a temperature of evaporator blowing air, Te, the water temperature sensor104detecting a temperature of hot water (engine coolant), Tw, flowing into a heating heat exchanger13, and a vibration sensor105(detector) detecting a vibration (that is, noise) of the motor37bof the air blower37.

The vibration sensor105is provided in the present embodiment on an assumption that the motor37bof the air blower37is one of causes of noise which is generated when the air blower37is operated to blow a desired amount of blowing air while a desired blow mode is performed. That is, the vibration sensor105is provided to detect a vibration level of the motor37bas a noise level. The vibration sensor105is provided to an outer wall of the motor37b.

The air conditioning operation panel110is provided with various air conditioning operation members, such as a temperature setting switch111as an example of a temperature setting device used to set a compartment temperature, a blow mode switch112used to manually set a blow mode switched from one to another by the rotary door15, an inside-outside air selector switch113used to manually set an inside-outside air suction mode by the inside-outside air switching door35, an air conditioner switch114used to output an operation command signal (ON signal of the electromagnetic clutch140a) to the compressor140, an air blower actuation switch115used to manually set an air volume of the air blower37, an automatic switch116used to output a command signal to execute an automatic mode, and so on.

Blow modes of the present embodiment include a face mode (FACE), a foot mode (FOOT), a bi-level mode, a foot-defroster mode (F/D), a defroster mode (DEF), and so on.

An electromagnetic clutch140aof the compressor140, servo motors36,120,121,122, and123as examples of electrical drive devices of respective devices, the motor37bof the air blower37, the motor141bof the condenser-cooling cooling fan141a, and so on are connected to an output side of the air conditioner ECU26. Operations of the foregoing devices are controlled by an output signal of the air conditioner ECU26.

The servo motor36rotary drives the inside-outside air switching door35. The servo motor120rotary drives the air mixing door14. The servo motor121rotary drives the adjusting door80. The servo motor122rotary drives the adjusting door81. The servo motor123rotary drives the rotary door15.

Air conditioning control processing by the air conditioner ECU26of the present embodiment will now be described with reference toFIG. 18andFIG. 19.FIG. 18shows a flowchart depicting basic air conditioning control processing by the air conditioner ECU26.FIG. 19shows a flowchart depicting adjusting door control processing by the air conditioner ECU26. The air conditioner ECU26performs the air conditioning control processing and the adjusting door control processing in parallel.

The following will describe the air conditioning control processing prior to the adjusting door control processing. Firstly, when an ignition switch is switched ON and DC power is supplied from a battery to the air conditioner ECU26, a routine ofFIG. 18is started and initialization is executed (Step S1). Subsequently, switch signals are read from the various switches, such as the temperature setting switch111(Step S2).

Subsequently, sensor signals converted from analog to digital form are read from the inside air temperature sensor101, the outside air temperature sensor100, the solar radiation sensor102, the evaporator temperature sensor103, and the water temperature sensor104(Step S3).

Subsequently, a target blow temperature TAO of air to be blown into the compartment is calculated in accordance with Equation (1) below pre-stored in the ROM (Step S4).
TAO=Kset×Tset−KR×TR−KAM×TAM−KS×TS+C(1)

The target blow temperature TAO is a temperature of air that needs to be blown out from the blowing openings51b,51c, and51dto maintain a compartment temperature at a pre-set temperature Tset.

Herein, Tset is a pre-set temperature set via the temperature setting switch111, TR is an inside air temperature detected by the inside air temperature sensor101, TAM is an outside air temperature detected by the outside air temperature sensor100, TS is an amount of solar radiation detected by the solar radiation sensor102. In addition, Kset, KR, KAM, and KS are gains and C is a correction constant.

Subsequently, a volume of blowing air the air blower37is to flow (hereinafter, referred to as the target volume of blowing air) is determined according to the target blow temperature TAO, an output signal of the air blower actuation switch115, and an output signal of the automatic switch116.

In a case where a volume of blowing air from the air blower37is manually set by an operation on the air blower actuation switch115, the manually set volume of blowing air is determined as the target volume of blowing air.

Herein, the manually set volume of blowing air is any one of a low level (blower Lo), a middle level (blower Mi), and a high level (blower Hi).

In a case where the automatic mode is set by an operation on the automatic switch116, a blower voltage (that is, a voltage applied to the motor37bof the air blower fan37a) corresponding to the target blow temperature (TAO) is determined from a characteristic chart pre-stored in a memory (Step S5). The blower voltage determined in the manner as above and a volume of blowing air the air blower37is to blow are in a one-to-one correspondence. Hence, the target volume of blowing air is determined according to the target blow temperature (TAO) in the automatic mode. A part of the air conditioner ECU26performing a control operation in Step S5may be used as an example of a second decider which decides a volume of blowing air the air blowing unit20is to generate.

A volume of blowing air set in the automatic mode is any one a low level (blower Lo), a middle level (blower Mi), and a high level (blower Hi).

Subsequently, a blowing outlet mode is determined according to the target blow temperature TAO and an output signal of the blow mode switch112(Step S6). A part of the air conditioner ECU26performing a control operation in Step S6may be used as an example of a first decider which decides one of the blowing openings51b,51c, and51das a blowing opening from which an airflow is to be blown out.

In a case where the automatic mode is set by a user via the automatic switch116, the blowing outlet mode to be executed is determined from any one of the face mode, the bi-level mode, and the foot mode according to the target blow temperature TAO with reference to a characteristic chart pre-stored in the memory.

In a case where the blowing outlet mode is set manually by the user via the blow mode switch112, the manually-set one mode is determined as the blowing outlet mode to be executed.

The blowing outlet mode to be executed is determined according to the manual setting via the blow mode switch112and the target blow temperature TAO in the manner as above.

Subsequently, a target door opening degree (SW) of the air mixing door14is calculated in accordance with Equation (2) below pre-stored in the ROM (Step S7).
SW={(TAO−TE)/(TW−TE)}×100(%)  (2)
where TE is a post-evaporation temperature detected by the evaporator temperature sensor103and a coolant temperature detected by the water temperature sensor104.

When a calculation result is SW≤0(%), the air mixing door14is controlled to stay at a position (MAXCOOL position) at which cold air from the cooling heat exchanger12is entirely forced to detour around the heating heat exchanger13. When the calculation result is SW≥100(%), the air mixing door14is controlled to stay at a position (MAXHOT position) at which cold air from the cooling heat exchanger12is entirely passed through the heating heat exchanger13.

When the calculation result is 0(%)<SW<100(%), the air mixing door14is controlled to stay at a position at which cold air from the cooling heat exchanger12is partly passed through the heating heat exchanger13and a rest of the cold air is forced to detour around the heating heat exchanger13.

Subsequently, an inside-outside air suction mode is determined according to settings via an inside-outside air selector switch73on the air conditioning operation panel110(Step S8).

Subsequently, an operation condition of the compressor140is determined when an air conditioner switch74is ON. That is, whether the compressor140is turned ON or OFF is determined according to the post-evaporation temperature (TE) detected by the evaporator temperature sensor103(Step S9). More specifically, when the post-evaporation temperature (TE) detected by the evaporator temperature sensor103is as high as or higher than a first frost formation temperature (for example, 4° C.), the refrigeration cycle device139is actuated by controlling (turning ON) energization of the electromagnetic clutch140ato start (turn ON) the compressor140. In short, the cooling heat exchanger12is actuated. When the post-evaporation temperature (TE) detected by the evaporator temperature sensor103is as high as or lower than a second frost formation temperature (for example, 3° C.) lower than the first frost formation temperature, the refrigeration cycle device139in operation is stopped by controlling (turning OFF) energization of the electromagnetic clutch140ato stop (turn OFF) the compressor140in operation. In short, an air cooling function of the cooling heat exchanger12is stopped.

Subsequently, control signals are outputted to actuators14,22, and53, the motor37bof the air blower fan37a, and the electromagnetic clutch140ato obtain the respective control conditions calculated or determined in Steps S5, S6, S7, and S9(Step S9A). A part of the air conditioner EUC26performing a control operation in Step S9A may be used as an example of a first controller which controls the rotary door15to allow one (second door opening) of multiple door openings64,65, and66to communicate with one (first blowing opening) of multiple blowing openings51b,51c, and51d. Alternatively, the part of the air conditioner EUC26performing the control operation in Step S9A may be used as an example of a second controller which controls the air blowing unit20to blow a predetermined volume of blowing air.

In Step S9B, a determination is made as to whether a time elapsed after read processing in Step S2has started (hereinafter, referred to as the elapsed time) reaches or exceeds a control cycle time t (for example, 0.5 seconds to 2.5 seconds).

When the elapsed time is less than the control cycle time t, a negative determination (NO) is made in Step S9B and the flow returns to Step S9B. Hence, a negative determination is repetitively made in Step S9B as long as the elapsed time is less than the control cycle time t. When the elapsed time reaches or exceeds the control cycle time t, a positive determination (YES) is made in Step S9B and the flow returns to S2to repeat processing operations in respective Steps S2, S3, S4, S5, S6, S7, S8, S9, S9A, and S9B.

The adjusting door control processing will now be described. Firstly, whether a detection value detected by the vibration sensor105is equal to or larger than a reference value is determined (Step S10). When the detection value detected by the vibration sensor105is less than the reference value, a negative determination (NO) is made. In response to the negative determination, the adjusting doors80and81are stopped at normal stop positions by controlling the servo motors121and122, respectively (Step S11). When the detection value detected by the vibration sensor105is equal to or larger than the reference value, a positive determination (YES) is made. In response to the positive determination, the adjusting doors80and81are stopped at noise reduction stop positions by controlling the servo motors121and122, respectively (Step S12). A part of the air conditioner ECU26performing a control operation in Step S12may be used as an example of a third controller which controls the adjusting doors80and81.

The normal stop positions and the noise reduction stop positions of the adjusting doors80and81of the present embodiment will now be described.

The normal stop positions of the adjusting doors80and81in the face mode are shown inFIG. 15. That is, the adjusting door80at the normal stop position stays on the inner side of the outer peripheral portion61in the direction of the radius. The adjusting door81at the normal stop position stays on the inner side of the outer peripheral portion63in the direction of the radius.

The normal stop positions of the adjusting doors80and81in the bi-level mode are shown inFIG. 20. That is, the adjusting door80at the normal stop position stays on the inner side of the outer peripheral portion61in the direction of the radius. The adjusting door81at the normal stop position stays on the inner side of the outer peripheral portion63in the direction of the radius

The normal stop positions of the adjusting doors80and81in the foot mode are shown inFIG. 21. That is, the adjusting door80at the normal stop position stays on the inner side of the outer peripheral portion61in the direction of the radius. The adjusting door81at the normal stop position stays on the inner side of the outer peripheral portion63in the direction of the radius.

The normal stop positions of the adjusting doors80and81in the foot-defroster mode are shown inFIG. 22. That is, the adjusting door80at the normal stop position stays on the inner side of the outer peripheral portion61in the direction of the radius. The adjusting door81at the normal stop position stays on the inner side of the outer peripheral portion63in the direction of the radius.

The normal stop positions of the adjusting doors80and81in the defroster mode are shown inFIG. 23. That is, the adjusting door80at the normal stop position stays on the inner side of the outer peripheral portion61in the direction of the radius. The adjusting door81at the normal stop position stays on the inner side of the outer peripheral portion63in the direction of the radius.

In the manner as above, the adjusting doors80and81do not change areas A1, A2, A3, and A4and areas B1, B2, B3, and B4.

In the present embodiment, it is assumed that the adjusting doors80and81are at the noise reduction stop positions in the face mode, the foot mode, and the defroster mode.

The noise reduction stop positions of the adjusting doors80and81in the face mode are shown inFIG. 24.

At the noise reduction stop position ofFIG. 24, the outer peripheral portion80cof the adjusting door80slightly closes the face blowing opening51c. At the noise reduction stop position ofFIG. 24, the outer peripheral portion80cof the adjusting door81slightly closes an inlet opening30b.

The inlet opening30band the door opening66communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the inlet opening30band the door opening66is defined as an area A1. The face blowing opening51cand the door opening64communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the face blowing opening51cand the door opening64is defined as an area B1.

Then, the area A1and the area B1become closer to each other when the adjusting doors80and81stop at the noise reduction stop positions than when the adjusting doors80and81stop at the normal stop positions.

In the present embodiment, the area A1and the area B1are not necessarily equal to each other to reduce noise, and the area A1and the area B1may be different from each other on a condition that noise is reduced to an extent that a feeling of strangeness is not given to an occupant.

The noise reduction stop positions of the adjusting doors80and81in the foot mode are shown inFIG. 25. At the noise reduction stop position ofFIG. 25, the outer peripheral portion80cof the adjusting door80slightly closes a foot blowing opening51d. At the noise reduction stop position ofFIG. 25, the adjusting door81slightly closes an inlet opening30a.

A cross-sectional area of a flow path through which an air flow passes through the inlet opening30aand the door opening65is defined as an area A2, and a cross-sectional area of a flow path through which an airflow passes through the foot blowing opening51dand the door opening64is defined as an area B2.

Then, the area A2and the area B2become closer to each other when the adjusting doors80and81are at the noise reduction stop positions than when the adjusting doors80and81are at the normal stop positions.

In the present embodiment, the area A2and the area B2are not necessarily equal to each other to reduce noise, and the area A2and the area B2may be different from each other on a condition that noise is reduced to an extent that a feeling of strangeness is not given to an occupant.

The noise reduction stop positions of the adjusting doors80and81in the defroster mode are shown inFIG. 26. At the noise reduction stop position ofFIG. 26, the outer peripheral portion80cof the adjusting door80slightly closes the defroster blowing opening51b. At the noise reduction stop position ofFIG. 26, the outer peripheral portion80cof the adjusting door81slightly closes the inlet opening30a.

The inlet opening30aand the respective door openings65and64communicate with each other, and a cross-sectional area of a flow path through which an airflow passes through the inlet opening30aand both the door openings65and64is defined as an area A4. The defroster blowing opening51band the door opening66communicate with each other, and a cross-sectional area through which an airflow passes through the defroster blowing opening51band the door opening66is defined as an area B4.

Then, the area A4and the area B4become closer to each other when the adjusting doors80and81are at the noise reduction stop positions than when the adjusting doors80and81are at the normal stop positions.

In the present embodiment, the area A4and the area B4are not necessarily equal to each other to reduce noise, and the area A4and the area B4may be different from each other on a condition that noise is reduced to an extent that a feeling of strangeness is not given to an occupant.

In the present embodiment, a volume of air reduced by moving the adjusting doors80and81to the noise reduction stop positions in the face mode, the foot mode, and the defroster mode is preferably set to a small value so as not to give a feeling of strangeness to an occupant.

In the foot mode, the defroster mode, and the foot-defroster mode, the air mixing door14is set to a maximum warm mode (Maxwarm mood) to fully open the inlet opening30aand fully close the inlet opening30b. In the face mode, the air mixing door14is set to a maximum cool mode (Maxcool mood) to fully close the inlet opening30aand fully open the inlet opening30b. In the bi-level mode, the air mixing door14is set to an intermediate mode to open both of the inlet openings30aand30b.

According to the present embodiment described above, the air conditioner EUC26executes one of the multiple blow modes and controls the air blower37to blow a target volume of blowing air, and when a noise level is determined to be at or above the threshold value according to a detection value of the vibration sensor105, the adjusting doors80and81are stopped at the noise reduction stop positions by controlling the servo motors121and122, respectively. Accordingly, in the face mode, for example, a difference between the area A1and the area B1becomes smaller and the area A1and the area B1become closer to each other. Likewise, a difference between the area A2and the area B2in the foot mode becomes smaller and the area A2and the area B2become closer to each other, and a difference between the area A4and the area B4in the defroster mode becomes smaller and the area A4and the area B4become closer to each other. A noise level can be thus lowered.

The third embodiment has described a case where the vibration sensor105is provided to the motor37bof the air blower37. However, as is shown inFIG. 27, a sensor detecting a noise level may be provided to a portion other than the air blower37in the air conditioning unit10. Alternatively, a sensor detecting a noise level may be provided in the compartment. For example, the vibration sensor105may be provided to an A-pillar130, a ceiling131, or a front windshield132in the compartment.

Fourth Embodiment

The third embodiment above has described a case where the adjusting doors80and81are adjusted by controlling the servo motors121and122, respectively, when a detection value of the vibration sensor105is equal to or larger than the reference value. The present embodiment will describe a case where adjusting doors80and81are adjusted by controlling servo motors121and122, respectively, when an estimated value of a noise level is determined to be equal to or larger than a reference value before an air blower37and a rotary door15are controlled.

FIG. 28shows a flowchart depicting adjusting door control processing by an air conditioner ECU26of the present embodiment. The flowchart of the adjusting door control processing of the present embodiment depicts a part of the processing in Step S9A ofFIG. 18in detail.

The air conditioner ECU26performs the adjusting door control processing in accordance with the flowchart ofFIG. 28instead of the flowchart ofFIG. 19.

The air conditioner EUC26performs the adjusting door control processing after a volume of blowing air is determined in Step S5and the blowing outlet mode is determined in Step S6and before the air blower37and the rotary door15are controlled.

Firstly, a determination is made as to whether the blowing outlet mode determined in Step S6ofFIG. 18is a blow mode in which a noise level may possibly rise to or above the reference value (threshold value). In the present embodiment, a face mode, a foot mode, and a defroster mode are set as the blow mode in which a noise level may possibly rise to or above the reference value (seeFIG. 29).

When the blowing outlet mode determined in Step S6is a bi-level mode or a foot-defroster mode, it is determined that the blowing outlet mode determined in Step S6is not the blow mode in which the noise level may possibly rise to or above the reference value. Hence, a negative determination (NO) is made and advancement is made to Step S11, in which the adjusting doors80and81are located at normal stop positions by controlling the servo motors121and122, respectively. Meanwhile, when the blowing outlet mode determined in Step S6is any one of the face mode (FACE), the foot mode (FOOT), and the defroster mode (DEF), it is determined that the blowing outlet mode determined in Step S6is the blow mode in which the noise level may possibly rise to or above the reference value, in which case a positive determination (YES) is made in Step S20.

In the case of a positive determination, a determination is made in Step S21as to whether a noise level (hereinafter, referred to as the estimated noise level) estimated when the blowing outlet mode determined in Step S6is performed and the air blower37is controlled to blow a volume of blowing air determined in Step S5is a noise NG level. The noise NG level means that the noise level is at or above the reference value. A part of the air conditioner EUC26performing control operations in Steps S20and S21may be used as an example of a determiner which determines whether the estimated noise level is at or above a predetermined value.

In the present embodiment, as is set forth inFIG. 29, when a volume of blowing air in the face mode is at a high level (blower Hi) in a manual mode, the volume of blowing air is set at the noise NG level. When a volume of blowing air in the foot mode is at the high level (blower Hi) in the manual mode, the volume of blowing air is set at the noise NG level. When a volume of blowing air in the defroster mode is at a high level (blower Hi) in an automatic mode, the volume of blowing air is set at the noise NG level. When a volume of blowing air in the defroster mode is at the high level (blower Hi) in the manual mode, the volume of blowing air is set at the noise NG level.FIG. 29shows a relation that any one of the blowing outlet mode, a volume of blowing air, and the noise NG level can be specified from the other two in a one-to-one correspondence.

When it is determined in Step S21that the estimated noise level is the noise NG level according to a volume of blowing air determined in Step S5and the blowing outlet mode determined in Step S6, a positive determination (YES) is made in Step S21, in which case the adjusting doors80and81are located at the noise reduction stop positions by controlling the servo motors121and122, respectively.

In subsequent Step S23, a motor37bis controlled for the air blower37to blow a volume of blowing air determined in Step S5and the rotary door15is controlled via a servo motor123to execute the blowing outlet mode determined in Step S6.

When it is determined in Step S21that the estimated noise level is below the noise NG level, a negative determination (NO) is made in Step S21, in which case the adjusting doors80and81are located at the normal stop positions by controlling the servo motors121and122, respectively.

According to the embodiment described above, in a case where the air conditioner ECU26determines that an estimated value of a level of noise generated when the blowing outlet mode determined in Step S6ofFIG. 18is executed and the air blower37is controlled to blow the target volume of blowing air determined in Step S5is equal to or larger than the reference value, the adjusting doors80and81are located at the noise reduction stop positions by controlling the servo motors121and122, respectively, before the air blower37and the rotary door15are controlled. Accordingly, a difference between an area A1(A2or A3) and an area B1(B2or B3) becomes smaller. Hence, generation of noise at a level at or above the reference value can be forestalled.

The first embodiment above has described a case where the area A1which is a cross-sectional area of a flow path when an airflow passes through an inlet opening30band a door opening66is equal to the area B1which is a cross-sectional area of a flow path when an airflow passes through a face blowing opening51cand a door opening64in the face mode. However, configurations as follows may be adopted as well.

That is, let an area Ala be a cross-sectional area of a flow path when an airflow passes through the inlet opening30band the door opening66, and an area A1bbe a cross-sectional area of a flow path when an airflow passes through the inlet opening30aand a door opening65. Further, let an area A1(=A1a+A1b) be a sum of the area A1aand the area A1b. Then, the area A1and the area B1may be equal to each other.

Alternatively, let an area B5abe a cross-sectional area of a flow path when an airflow passes through the face blowing opening51cand the door opening64, and area B5bbe a cross-sectional area of a flow path when an airflow passes through a foot blowing opening51dand the door opening64in the bi-level mode. Further, let an area B5be a sum of the area B5aand the area B5b. Then, the area B5and the area A1(=A1a+A1b) may be equal to each other.

The first embodiment above has described a case where the area A2which is a cross-sectional area of a flow path when an airflow passes through an inlet opening30aand the door opening65is equal to the area B2bwhich is a cross-sectional area of a flow path when an airflow passes through the foot blowing opening51dand the door opening64in the foot mode. However, configurations as follows may be adopted as well.

A cross-sectional area of a flow path through which an airflow passes through the inlet opening30aand the door opening65is defined as an area A2a. A cross-sectional area of a flow path through which an airflow passes through the inlet opening30band the door opening66is defined as an area A2b. When a sum of the area A2aand the area A2bis defined as an area A2(=A2a+A2b), the area A2and the area B2may be equal to each other.

Likewise, the area A2(=A2a+A2b) and the area B3(=B3a+B3b) in the foot-defroster mode may be equal to each other.

Alternatively, let an area A4abe a cross-sectional area of a flow path when an airflow passes through the inlet opening30aand both of the door openings64and65, and an area A4bbe a cross-sectional area of a flow path when an airflow passes through the inlet opening30band the door opening66. Further, let an area A4(=A4a+A4b) be a sum of the area A4aand the area A4b. Then, the area A4and the area B4may be equal to each other.

The first, second, third, and fourth embodiments above have described a case where the air conditioner of the present disclosure is a vehicular air conditioner. However, the air conditioner of the present disclosure may be an air conditioner (for example, a stationary air conditioner) other than a vehicular air conditioner or an air conditioner equipped to various types of moving vehicles.

The first, second, third, and fourth embodiments above have described a case where the rotary door15includes three outer peripheral portions (61,62, and63). However, the rotary door15may include two or four outer peripheral portions instead.

The second embodiment above has described a case where the rotary door15is provided with the sound deadening materials70a,70b, and70c. However, a noise reflection plate reflecting noise may be additionally provided to the rotary door15. By combining the sound deadening materials70a,70b, and70cand the noise reflection plate, noise at more than one frequency can be attenuated.

The first, second, third, and fourth embodiments above have described a case where the rotary door15forms the mode switching door which switches the blow modes. However, the rotary door15may also form doors other than the mode switching door, such as an inside-outside air switching door and an air mixing door.

When the present disclosure is implemented, a sound deadening material and a noise reflection plate may be provided to the air mixing door14on the inner side in the direction of the radius in the first, second, third, and fourth embodiments.

The third and fourth embodiments have described a case where two adjusting doors (80and81) are provided. However, only one adjusting door (80or81) may be provided instead.

Alternatively, adjusting doors may be provided separately to a defroster blowing opening51b, the face blowing opening51c, and the foot blowing opening51d. In short, an adjusting door may be provided to each blowing opening.

The third and fourth embodiments above have described a case where a noise level is lowered by making the area A1(A2or A3) and the area B1(B2or B3) closer to each other by using the adjusting doors80and81. However, a configuration as shown inFIG. 30may be additionally adopted.

That is, the adjusting door80(or81) is disposed at a position indicated by a dotted line when an air flow path is formed between the door opening66and the defroster blowing opening51b. When configured in the manner as above, a cross-sectional area of the air flow path formed between the door opening66and the defroster blowing opening51bcan be reduced. Consequently, air is allowed to blow out from a fine opening between the door opening66and the defroster blowing opening51b.

Owing to the configuration as above, a velocity of an airflow flowing in the rotary door15from a side of the door opening65toward the defroster blowing opening51bas is indicated by an arrow Lm can be reduced. Hence, a level of noise generated due to an airflow can be lowered. In addition, because noise can be reflected on the adjusting door80(or81) in the rotary door15, transmission of noise from the rotary door15to the defroster blowing opening51bcan be prevented.

The third and fourth embodiments above have described a case where the face mode, the foot mode, and the defroster mode are the blow mode in which a noise level rises to or above the reference value. However, blow modes other than the face mode, the foot mode, and the defroster mode may be the blow mode in which a noise level rises to or above the reference value.

It should be appreciated that the present disclosure is not limited to the embodiments described above and can be modified as needed. The respective embodiments above are not independent to one another and can be combined unless a combination is apparently infeasible. It goes without saying that the elements forming the respective embodiments above are not essential unless specified as being essential or deemed as being essential in principle.

While the present disclosure has been described with reference to embodiments thereof, it is to be understood that the disclosure is not limited to the embodiments and constructions. To the contrary, the present disclosure is intended to cover various modification and equivalent arrangements. In addition, while the various elements are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure.