Air conditioning for vehicle

Abstract

Air conditioning system for a vehicle, which performs the climate control of a vehicle interior, including: a blower (16) that blows air into the vehicle interior; a circulation passage (51) through which a coolant circulates to cool an internal combustion engine (50); a heating core (55) which is arranged in the circulation passage (51) and is designed to heat air that is to be blown into the vehicle interior using the coolant; a diversion passage (56) connected to the circulation passage (51), wherein the diversion passage (56) is designed to cause the coolant to circulate while bypassing the heating core (55); a switching valve (54) which is arranged to switch between a first operating mode in which the coolant flowing from the internal combustion engine (50) flows through the diversion passage (56) and returns to the internal combustion engine (50) while bypassing the heating core (55) and a second operating mode in which the coolant flowing from the internal combustion engine (50) flows to the heating core (55); a coolant temperature sensor (53) that detects the temperature of the coolant at a part of the circulation passage (51) through which the coolant flows in both the first operating mode and the second operating mode; a control unit (61) for controlling the operation of the blower (16) based on coolant temperature control data; a first coolant temperature data calculation section (S102, S103) which is set up to calculate the coolant temperature control data in the first operating mode; and a second coolant temperature data calculation section (S106, S108, S110) which is set up to calculate the coolant temperature control data until a predetermined time has elapsed since switching to the second operating mode, wherein the first coolant temperature data calculation section (S102, S103) calculates the coolant temperature control data based on a coolant temperature detected by the coolant temperature sensor (53) when the internal combustion engine (50) is started, and the second coolant temperature data calculation section (S106, S108, S110) as the coolant temperature control data sets a temperature that is lower than the coolant temperature detected by the coolant temperature sensor (53).

Description

Field of invention

[0001] The present disclosure relates to an air conditioning system for a vehicle which heats air to be blown into the interior of a vehicle using a coolant for cooling an internal combustion engine. Background technology

[0002] Traditionally, some vehicles are known to be equipped to switch between a first operating mode, in which a coolant circulates to cool an internal combustion engine (referred to below as an internal combustion engine) while bypassing a heater core, and a second operating mode, in which the coolant flows through the heater core. When the coolant temperature is low, such as during a cold start, the first operating mode is engaged. As the temperature rises, the first operating mode is switched to the second.

[0003] In such vehicles, a coolant temperature sensor, which measures the coolant temperature, is located in a part where the coolant flows continuously. This type of technology is described, for example, in JP 2007-223 418 A.

[0004] In conventional air conditioning systems, the coolant temperature measured by the coolant temperature sensor is used as coolant temperature control data, and based on this data, air volume, blow-out air temperature, and similar parameters are controlled. In a vehicle air conditioning system, where the refrigerant flows continuously through the heater core, the coolant temperature control data corresponds to an estimated temperature of the heater core.

[0005] However, in a vehicle configured to switch coolant flow between the first and second operating modes, the coolant circuit is divided in the first mode into an engine-side coolant circuit and a heater core-side circuit. This results in different temperatures for the coolant in each circuit. The engine-side coolant circuit is one in which the coolant temperature increases due to the heat generated by the internal combustion engine in the first operating mode. The heater core-side circuit is one in which the coolant temperature does not increase, unaffected by the heat generated by the internal combustion engine in the first operating mode.

[0006] Because the coolant temperature sensor is located in a component through which the coolant constantly flows, the coolant temperature in the heater core-side circuit is not detected in the first operating mode. If the coolant temperature in the engine-side coolant circuit, as detected by the coolant temperature sensor, were used as the coolant temperature control data, a significant difference would exist between the coolant temperature control data and the heater core temperature. Consequently, in this case, the control of air volume, blower air temperature, and similar parameters could not be performed correctly, thus impairing the comfort provided by the air conditioning system.

[0007] There is a time lag between when the operating mode switches to the second operating mode and when the high-temperature coolant in the engine-side coolant circuit reaches the heater core. During this time lag, a difference occurs between the coolant temperature measured by the coolant temperature sensor and the coolant temperature in the heater core.

[0008] If the coolant temperature measured by the coolant temperature sensor in the engine-side coolant circuit is used as the coolant temperature control data, the difference between the coolant temperature control data and the heater core temperature would be large. Consequently, controlling the air volume, blower air temperature, and similar parameters would be difficult and impair comfort.

[0009] After a cold start in winter, the first operating mode is selected for the purpose of warming up the combustion engine at an early stage. In this first operating mode, the coolant temperature in the heater core is a low temperature, corresponding to the outside air temperature (for example, -30°C).

[0010] The engine warm-up phase then ends, and the system switches to the second operating mode. In this mode, the high-temperature coolant in the engine-side coolant circuit flows into the heater core-side circuit. After a predetermined time has elapsed since switching to the second operating mode, the high-temperature coolant in the engine-side coolant circuit reaches the heater core, thus raising the heater core temperature to, for example, 80°C.

[0011] Meanwhile, immediately after switching to the second operating mode, the low-temperature coolant in the heater core circuit flows into the engine-side coolant circuit, temporarily reducing the coolant temperature in the engine-side circuit. When the coolant, whose temperature has been temporarily reduced, reaches the heater core, the heater core temperature is also reduced, for example, to 50 to 60°C.

[0012] Subsequently, the temperature of the entire coolant in the circuits increases to a target coolant temperature, so that the coolant as a whole is isothermalized.

[0013] As a result, in the air conditioning system, which uses the air as a heat source by circulating the refrigerant through the heating core, the blown air temperature varies, accompanied by the aforementioned phenomenon, i.e., the change in the heating core temperature after switching to the second operating mode, thus affecting comfort.

[0014] In standard vehicle air conditioning systems, warm-up control is used to limit airflow when the coolant temperature is low. In this case, the airflow varies along with fluctuations in coolant temperature detected by the coolant temperature sensor after switching to the second operating mode, thus impairing comfort. Similarly, in various types of control systems that operate based on coolant temperature control data, fluctuations in the coolant temperature detected by the coolant temperature sensor can cause oscillations, also affecting comfort.

[0015] If an additional coolant temperature sensor is installed in the heating core circuit, the aforementioned problems will not occur. In such a case, adding the coolant temperature sensor will increase costs.

[0016] DE 10 2014 102 078 A1 discloses a known air conditioning system for a vehicle, which performs the air conditioning of a vehicle interior and comprises the following: a blower that blows air into the vehicle interior; a circulation passage through which a coolant circulates for cooling an internal combustion engine; a heating core that is arranged in the circulation passage and is designed to heat air to be blown into the vehicle interior using the coolant; a diversion passage connected to the circulation passage, the diversion passage being designed to cause the coolant to circulate while bypassing the heating core;a switching device configured to switch between a first operating mode in which the coolant flowing from the internal combustion engine passes through the bypass and returns to the internal combustion engine, bypassing the heating core, and a second operating mode in which the coolant flowing from the internal combustion engine flows to the heating core; coolant temperature sensors for detecting the temperature of the coolant; and a control unit for controlling the operation of the blower. Summary of the invention

[0017] The object of the present invention is to improve the climate comfort provided by an air conditioning system for a vehicle that performs the climate control of a vehicle interior.

[0018] The object of the present invention is achieved by an air conditioning system for a vehicle, which performs the air conditioning of a vehicle interior, with the features of claim 1.

[0019] Advantageous embodiments of the present invention are defined in the dependent claims.

[0020] It is an advantage of the present invention to provide an air conditioning system for a vehicle, which performs the climate control of a vehicle interior and improves climate comfort for an occupant, without the need to additionally install another coolant temperature sensor to detect the coolant temperature in the air conditioning system installed in the vehicle, which is designed to switch and fix the flow of an engine coolant. An air conditioning system for a vehicle, which performs the climate control of a vehicle interior, comprises: a blower that blows air into the vehicle interior; a circulation passage through which a coolant circulates for cooling an internal combustion engine; a heating element arranged in the circulation passage and designed to heat the air to be blown into the vehicle interior using the coolant;a diversion passage connected to the circulation passage, the diversion passage being configured to cause the coolant to circulate while bypassing the heater core; a switching device configured to toggle between a first operating mode in which the coolant flowing from the internal combustion engine passes through the diversion passage and returns to the internal combustion engine while bypassing the heater core, and a second operating mode in which the coolant flowing from the internal combustion engine flows to the heater core; a coolant temperature sensor that detects the temperature of the coolant at a portion of the circulation passage through which the coolant flows in both the first and second operating modes; a control unit that controls the operation of the blower based on coolant temperature control data;a first coolant temperature data calculation section that calculates the coolant temperature control data in the first operating mode; and a second coolant temperature data calculation section that calculates the coolant temperature control data until a predetermined time has elapsed since switching to the second operating mode. The first coolant temperature data calculation section calculates the coolant temperature control data based on a coolant temperature detected by the coolant temperature sensor when the internal combustion engine is started, and the second coolant temperature data calculation section sets the coolant temperature control data to a temperature lower than the coolant temperature detected by the coolant temperature sensor.

[0021] While the first operating mode is thus established, the coolant temperature control data is based on the coolant temperature measured by the coolant temperature sensor when the internal combustion engine is started. This makes it possible to reduce the difference between the coolant temperature control data and the actual temperature of the heater core. Therefore, the control of air volume, blow-out air temperature, and similar parameters can be appropriately implemented, thereby improving the comfort provided by the air conditioning system.

[0022] Until the predetermined time has elapsed since switching to the second operating mode, a temperature lower than the coolant temperature detected by the coolant temperature sensor is used as the coolant temperature control data. Consequently, the difference between the coolant temperature control data and the actual temperature of the heater core can be reduced. Therefore, the control of air volume, blown air temperature, and similar parameters can be appropriately implemented, thus improving comfort.

[0023] Furthermore, until the specified time has elapsed since switching to the second operating mode, fluctuations in the coolant temperature control data are suppressed, thereby suppressing fluctuations in the air volume as well as the occurrence of oscillation in different control modes. Brief description of the drawings Fig. 1 is a diagram showing the overall structure of a vehicle air conditioning system according to one embodiment; Fig. 2 is a block diagram showing the electrical setup of the Fig. The vehicle air conditioning system shown in section 1 is shown; Fig. 3 is a diagram explaining the operation of the vehicle air conditioning system according to the embodiment; and Fig. 4 is a flowchart showing the tax processing carried out by a Fig. The air conditioning control shown in section 2 is executed. Description of embodiments: The following describes one embodiment.

[0024] As in Fig. 1 and Fig. Figure 2 shows a vehicle air conditioning system 100 mounted on a vehicle which receives a driving force from an internal combustion engine (hereinafter referred to as an internal combustion engine) 50 as a driving force source.

[0025] The internal combustion engine 50 includes a circulation passage 51 through which an engine coolant circulates to cool the internal combustion engine 50.

[0026] A coolant pump 52, a coolant temperature sensor 53, a switching valve 54, and a heater core 55 are arranged in the circulation passage 51. The coolant pump 52 causes the engine coolant to circulate in the circulation passage 51. The coolant temperature sensor 53 detects the temperature of the engine coolant and outputs an electrical signal corresponding to the detected temperature. The switching valve 54 is a switching valve that opens and closes the circulation passage 51.

[0027] The coolant pump 52 is driven by an electric motor. The amount of power supplied to the electric motor of the coolant pump 52 is controlled by a motor controller 57, thereby controlling the flow rate of the coolant flowing through the circulation passage 51. The switching valve 54 is driven by an electromagnet or electric motor and controlled by the motor controller 57. The coolant temperature sensor 53 used is a heat-sensitive element, for example, a thermistor. An electrical signal output by the coolant temperature sensor 53 is fed into the motor controller 57.

[0028] The circulation passage 51 is connected to a diversion passage 56, causing the engine coolant to circulate through it while bypassing the heater core 55. Specifically, one end of the diversion passage 56 is connected in the circulation passage 51 between the combustion engine 50 and the switching valve 54, while the other end of the diversion passage 56 is connected in the circulation passage 51 between the combustion engine 50 and the heater core 55.

[0029] When the switching valve 54 closes the circulation passage 51, the engine coolant flowing from the internal combustion engine 50, as indicated by a dashed arrow with reference numeral A, flows through the diversion passage 56 and thus returns to the internal combustion engine 50, bypassing the heating core 55.

[0030] When the switching valve 54 opens the circulation passage 51, the engine coolant is allowed to flow to the heater core 55. Thus, the engine coolant flowing from the internal combustion engine 50 returns to the internal combustion engine 50 through the heater core 55 at this time, as indicated by a dashed arrow with the reference symbol B.

[0031] The coolant temperature sensor 53 is arranged as the part through which the engine coolant flows either when the switching valve 54 closes the circulation passage 51, or when the switching valve 54 opens the circulation passage 51. In particular, the coolant temperature sensor 53 is arranged between the internal combustion engine 50 and the aforementioned one side of the bypass passage 56.

[0032] The vehicle air conditioning system 100 comprises a refrigeration circuit 1, an air conditioning unit 8, and an air conditioning controller 61. The vehicle air conditioning system 100 is an automatic climate control system that regulates the climate control of the vehicle interior. Specifically, the vehicle air conditioning system 100 is designed to control the air conditioning unit 8, which in turn regulates the climate control of the vehicle interior using the air conditioning controller 61.

[0033] The climate control unit 8 is located within an instrument panel in the front section of the vehicle interior. The climate control unit 8 draws in interior air and / or exterior air and adjusts the temperature of the drawn-in air before blowing it into the vehicle interior.

[0034] The air conditioning unit 8 comprises an evaporator 7, an air conditioning housing 10, an indoor / outdoor air diverter flap 13, a blower 16, an air mixing flap 17, several air outlet diverter flaps 21 and 22, and the heating core 55. The evaporator 7 is included in the refrigeration circuit 1 as well as in the air conditioning unit 8.

[0035] The air conditioning housing 10 forms a housing for the air conditioning unit 8. One side of the air conditioning housing 10 is provided with air intake openings 11 and 12, while its other side is provided with several air outlets through which air flows towards the vehicle interior. The air conditioning housing 10 has a ventilation passage 10a arranged between the air intake openings 11 and 12 and the air outlet, through which the ventilation air passes.

[0036] The air conditioning housing 10 has on its upstream side (i.e., one side) an air intake section 101 with two air intake openings 11 and 12 formed therein. One of the two air intake openings 11 and 12 is an indoor air intake opening 11, which draws in the indoor air, and the other of these is an outdoor air intake opening 12, which draws in the outdoor air.

[0037] The indoor / outdoor air switching damper 13 is an opening / closing device for an intake opening, increasing and decreasing the degree of opening of the indoor air intake opening 11 and the degree of opening of the outdoor air intake opening 12. The indoor / outdoor air switching damper 13 rotates within the air intake section 101 and is driven by an actuator, such as a servo motor. Specifically, the indoor / outdoor air switching damper 13 rotates such that when one of the indoor air intake openings 11 and the other of the outdoor air intake opening 12 is more open, the other is more closed, thereby adjusting the ratio of the flow rate of indoor air entering the air intake section 101 to the flow rate of outdoor air entering it. The degree of opening of the internal air intake opening 11 is a degree of opening of the internal air intake opening 11, while the degree of opening of the external air intake opening 12 is a degree of opening of the external air intake opening 12.

[0038] The blower 16 blows the air in such a way that the air flowing into the air intake section 101 flows to the evaporator 7, and then the air flowing through the evaporator 7 flows out into the vehicle interior. Therefore, the blower 16 has a fan wheel 161 as a centrifugal fan and a blower electric motor 162, which is coupled to the fan wheel 161.

[0039] The impeller 161 of the blower 16 is located on the downstream side of the airflow in the air conditioning housing 10 with respect to the air intake section 101 and on the upstream side of the airflow with respect to the evaporator 7. The impeller 161 comprises several fan blades and is driven by a blower electric motor 162, which is controlled by the air conditioning control unit 61, thereby generating an airflow towards the vehicle interior within the air conditioning housing 10. For example, the rotational speed of the impeller 161 in the blower 16 is controlled by the air conditioning control unit 61 to increase or decrease the volume of air blown from the respective air outlets towards the vehicle interior.

[0040] The evaporator 7 is located on the downstream side of the airflow in the air conditioning housing 10, relative to the impeller 161 of the blower 16. The evaporator 7 is an air-cooling heat exchanger. That is, the evaporator exchanges heat between the refrigerant, which is decompressed by an expansion valve 6, and the ventilation air conveyed by the blower 16, thereby cooling the ventilation air while the refrigerant evaporates and vaporizes through the heat exchange.

[0041] The heating core 55 is located on the downstream side of the airflow relative to the air conditioning housing 10 and is positioned to partially cover the ventilation passage 10a. The heating core 35 heats the ventilation air passing through the ventilation passage 10a by exchanging heat between the ventilation air and the engine coolant.

[0042] The air mixing flap 17 is located on the upstream side of the airflow relative to the heater core 55 and on the downstream side of the airflow relative to the evaporator 7. The air mixing flap 17 is driven by an actuator, such as a servo motor, to change the temperature of the air blown from each air outlet towards the vehicle interior. In other words, the air mixing flap 17 adjusts the ratio of the air volume between cold air, which passes through the evaporator 7 and bypasses the heater core 55, and hot air, which passes through the evaporator 7 and then the heater core 55, depending on the rotational position of the air mixing flap 17.

[0043] In refrigeration circuit 1, the refrigerant circulating through the circuit absorbs heat in the evaporator 7 and releases heat in the condenser 3. Refrigeration circuit 1 consists of a compressor 2, the condenser 3, a receiver 5, an expansion valve 6, the evaporator 7, and refrigerant lines connecting these components in a ring configuration.

[0044] Compressor 2 is coupled to the internal combustion engine 50 via an electromagnetic clutch (not shown). Compressor 2 receives a drive force from the internal combustion engine 50 to draw in, compress, and discharge the refrigerant. The interruption of the electromagnetic clutch, which is inserted between compressor 2 and the internal combustion engine 50, is controlled by the air conditioning control unit 61.

[0045] Condenser 3 is located in a position, such as an engine compartment, that is sensitive to the airflow generated when the vehicle is in motion. The refrigerant compressed by compressor 2 flows into condenser 3, where it condenses and liquefies. This means that condenser 3 exchanges heat between the refrigerant flowing inside it and the airflow generated by the vehicle and the outside air blown by an external fan 4.

[0046] The collector 5 separates a liquid-phase refrigerant and a vapor-phase refrigerant contained in the refrigerant flowing from the condenser 3. The collector 5 causes the separated liquid-phase refrigerant to flow out of the expansion valve 6.

[0047] The expansion valve 6 decompresses and expands the refrigerant from the receiver 5, causing the decompressed and expanded refrigerant to flow out of the evaporator 7. The evaporator 7 then evaporates and vaporizes the refrigerant from the expansion valve 6. The refrigerant that evaporates and vaporizes in the evaporator 7 is drawn into the compressor 2.

[0048] The air conditioning housing 10 is provided with a defrost opening 18, a face opening 19 and a foot opening 20. These openings 18, 19 and 20 are arranged on the downstream side of the airflow in the air conditioning housing 10.

[0049] The defroster opening 18 is connected to a defroster duct 23. At the end of the downstream side of the defroster duct 23, a defroster air outlet 18a is open. The defroster air outlet 18a blows mainly hot air towards an inner surface of a windshield 49a of the vehicle, i.e., an inner surface of the front glass window 49a.

[0050] The face opening 19 is connected to a face channel 24. At the end of the downstream side of the face channel 24, a face air outlet 19a is open. The face air outlet 19a blows mainly cold air towards the head and chest of an occupant.

[0051] Furthermore, the foot opening 20 is connected to a foot channel 25. At the end of the downstream side of the foot channel 25, a foot air outlet 20a is open to blow mainly hot air towards the occupant's foot.

[0052] Inside the respective openings 18, 19, and 20, two air outlet switching flaps 21 and 22 are rotatably mounted. Each of the two air outlet switching flaps 21 and 22 is driven by an actuator, such as a servo motor. The two air outlet switching flaps 21 and 22 are capable of selectively switching an air outlet operating mode of the air conditioning unit 8 between the face operating mode, the dual-height operating mode, the foot operating mode, the foot defrost operating mode, and the defrost operating mode.

[0053] The following section describes an electrical configuration of the vehicle air conditioning system 100. As in Fig. As shown in Figure 2, switching signals from respective switches on a control panel 70 provided on the front surface of the vehicle interior, sensor signals from respective sensors and communication signals output by the engine control unit 57, and similar signals are entered into the climate control unit 61.

[0054] This section describes the control panel 70. The control panel 70 is integrally mounted with the instrument panel. The control panel 70 includes, for example, a liquid crystal display, an indoor / outdoor air selector switch, a defroster switch, a blower mode selector switch, a blower air volume selector switch, an automatic switch, a temperature setting switch, and an air conditioning switch 70a.

[0055] The liquid crystal display (LCD) has a display area provided to visually indicate a preset temperature, blowing mode, blowing air volume, and similar information. The LCD can also have a display area for visually indicating, for example, an outside air temperature, an intake mode, a time, and similar information.

[0056] Several switches on the control panel 70 are described below. The defroster switch is a switch that sets the blower mode to the defroster mode and commands the improvement of the anti-fog capacity of a front glass window 49a. The operating mode selector switch is a switch that requests that the blower mode be set to one of the face mode, dual-height mode, foot mode, or foot defroster mode according to a manual operation by an occupant. The temperature setting switch is a switch for setting the temperature to a desired temperature.

[0057] The air conditioning switch 70a is a switch that commands the compressor 2 in the refrigeration circuit 1 to start and stop. When the air conditioning switch 70a is turned on with the ignition on, the air conditioning unit 8 performs an air conditioning operation in which air cooled by the evaporator 7, or air cooled by the evaporator 7 and heated by the heater core 55, is blown into the vehicle interior. The automatic switch is a switch that commands the execution of the automatic air conditioning control, which results in the automatic climate control of the vehicle interior.

[0058] Within the air conditioning control unit 61, the familiar microcomputer is provided, possessing (not shown) functions including a CPU for performing arithmetic and control processing (i.e., a central processing unit), memory such as ROM and RAM, and an I / O port (i.e., input / output circuitry). Both the RAM and ROM are non-volatile physical storage media. After the sensor signals from the various sensors have been converted from analog to digital, i.e., by the I / O port or the A / D converter circuitry, they are fed into the microcomputer.

[0059] The climate control unit 61 is connected to an indoor air temperature sensor 71 and an outdoor air temperature sensor 72. The indoor air temperature sensor 71 detects the indoor air temperature, which is the temperature of the air around a driver's seat inside the vehicle. The outdoor air temperature sensor 72 detects the outdoor air temperature, which is the temperature of the air outside the vehicle interior.

[0060] The interior air sensor 71 and the exterior air sensor 72 utilize a heat-sensitive element, for example, a thermistor. The interior air sensor 71 is located in a part around the driver's seat (for example, inside the instrument panel near the steering wheel) that is hardly affected even if any air outlet other than the driver's seat air outlet is closed.

[0061] An ignition switch 73 is connected to the climate control unit 61. A switching signal for the switch, indicating a switching position of the ignition switch 73, is also input into the climate control unit 61. The ignition switch 73 is located near the driver's seat and is operated by an occupant. The ignition switch 73 is the familiar switch for toggling the operation of the internal combustion engine 50 between an enabling state and a disabling state. For example, the ON position of the ignition switch 73 is a switching state that enables the operation of the internal combustion engine 50, while the OFF position of the ignition switch 73 is a switching state that disables the operation of the internal combustion engine 50 and switches off predefined accessory equipment, such as an audio device. Thus, after finishing using the vehicle, the occupant switches the ignition switch 73 OFF.

[0062] A communication signal or similar output from the engine control unit 57 is input into the climate control unit 61. Specifically, information about the flow rate of coolant circulating through the circulation port 51, the engine coolant temperature detected by the coolant temperature sensor 53, the operating status of the switching valve 54, and similar data is input into the climate control unit. The engine control unit 57 calculates the flow rate of the coolant circulating through the circulation port 51 based on the amount of power supplied to the electric motor of the coolant pump 52.

[0063] Next, the engine coolant control processing, which is performed by the engine control unit 57, will be described.

[0064] When the internal combustion engine 50 is started, the switching valve 54 first receives a control signal from the engine control unit 57 to close the circulation passage 51. The coolant pump 52 then receives a control signal from the engine control unit 57 to cause the engine coolant to circulate within the circulation passage 51.

[0065] When the switching valve 54 closes the circulation passage 51, the engine coolant flowing from the internal combustion engine 50 flows through the diversion passage 56 and thus returns to the internal combustion engine 50, bypassing the heating core 55.

[0066] Hereinafter, a coolant circuit formed when the switching valve 54 closes the circulation passage 51 is referred to as a first operating mode. A coolant circuit in the circulation passage 51 through which the engine coolant flows in the first operating mode is referred to as an engine-side coolant circuit. A coolant circuit in the circulation passage 51 through which the engine coolant does not flow in the first operating mode is referred to as a heater core-side circuit.

[0067] Here, the dotted line shows in Fig. 3. The temperature of the engine coolant, as detected by the coolant temperature sensor 53, i.e., the temperature of the engine coolant in the engine-side coolant circuit. As in Fig. As shown in Figure 3, the temperature of the engine coolant in the engine-side coolant circuit increases over time after the internal combustion engine 50 is started. When the engine coolant temperature reaches a predetermined temperature, the switching valve 54 receives a control signal from the engine control unit 57 to open the circulation passage 51.

[0068] When the switching valve 54 opens the circulation passage 51, the engine coolant flowing from the internal combustion engine 50 also flows to the circuit on the heater core side and returns to the internal combustion engine 50 through the heater core 55. A second operating mode of the coolant circuit, which is established when the switching valve 54 opens the circulation passage 51, is referred to below.

[0069] Now, the control processing performed by the air conditioning control unit 61 is based on Fig. 3 and Fig. 4 described. The alternating long and short dashed line in Fig. 3 indicates a heating core temperature of 55, while the solid line in Fig. 3 displays the coolant temperature control data.

[0070] In the control processing described in detail below, the air conditioning control unit 61 calculates the coolant temperature control data and controls the operation of an air conditioning control device, such as the blower 16, based on the coolant temperature control data.

[0071] When the vehicle's ignition switch 73 is turned on and the air conditioning switch 70a is turned ON, the air conditioning control unit 61 repeatedly and regularly performs the control processing as shown in the flowchart of Fig. 4 shown, through. While the air conditioning unit 8 is performing an air conditioning operation, the in Fig. The control processing shown in step 4 is executed in parallel with the air conditioning operation. That is to say, the Fig. The control processing shown in Figure 4 is executed in parallel with other control processing operations that affect the air conditioning operation of the air conditioning unit 8, for example the control processing included in the automatic air conditioning control.

[0072] First, the air conditioning control 61 determines in the Fig. 4 shown step S101 is based on information relating to the operating state of the switching valve 54 and output by the engine control 57, indicating whether a coolant circuit operating mode is the first operating mode or not.

[0073] If, as is the case immediately after starting the combustion engine 50, the temperature of the engine coolant, as detected by the coolant temperature sensor 53, is lower than a predetermined temperature, the switching valve 54 closes the circulation passage 51 and the first operating mode is established. Thus, a positive decision is made in step S101 and the processing continues to step S102.

[0074] In step S102, an estimated temperature of the heater core 55 (referred to below as an estimated heater core temperature) is calculated based on the information relating to the engine coolant, which is detected by the coolant temperature sensor 53 and output by the engine control unit 57.

[0075] In particular, the temperature of the engine coolant, as detected by the coolant temperature sensor 53, is essentially the same as the temperature of the heater core 55. Therefore, the estimated heater core temperature is considered to be the temperature of the engine coolant detected by the coolant temperature sensor 53 when the internal combustion engine 50 is started. This reduces the difference between the estimated heater core temperature and the actual temperature of the heater core 55.

[0076] The processing then continues from step S102 to step S103. In step S103, the coolant control temperature data is calculated. Specifically, if a positive decision is made in step S101, because the first operating mode is defined, the heater core temperature estimated in step S102 is used as the coolant temperature control data. Steps S102 and S103 establish an initial coolant temperature data calculation section.

[0077] The processing then proceeds from step S103 to step S104. In step S104, which acts as a control unit, a target operating value for the air conditioning control device, such as the blower, is calculated based on the coolant temperature control data calculated in step S103. A control signal corresponding to this calculated target operating value is then output to the air conditioning control device. The air conditioning control devices, other than the blower, can include the indoor / outdoor air diverter flap 13, the air mixing flap 17, and the air outlet diverter flaps 21 and 22.

[0078] The coolant control data is calculated in the manner described above while the first operating mode is set. Thus, as described in Fig. Figure 3 shows that the difference between the coolant temperature control data provided while the first operating mode is set and the actual temperature of the heating core 55 is reduced. Therefore, while the first operating mode is set, the control of the air volume, the blown air temperature, and similar parameters can be appropriately adjusted, thus improving comfort.

[0079] However, if the temperature of the engine coolant, as detected by the coolant temperature sensor 53, reaches a predetermined temperature after the combustion engine 50 has started operating, while the first operating mode is active, the switching valve 54 opens the circulation passage 51 to switch to the second operating mode. Thus, a negative decision is made in step S101, and the process then proceeds to step S105.

[0080] When switching from the first operating mode to the second operating mode, the affirmative decision is made in step S105, and the processing then continues to step S106.

[0081] In step S106, a time period is calculated during which a limited coolant temperature, which will be described later as the coolant temperature control data, is used, i.e. a target limitation time T.

[0082] As in Fig. As shown in Figure 3, the target limitation time T corresponds to a time interval (referred to below as the isothermalization time) from when the first operating mode is switched to the second operating mode until the temperature of the heating core 55 becomes substantially equal to the temperature of the engine coolant as detected by the coolant temperature sensor 53.

[0083] In particular, the target limitation period T is calculated as follows. The target limitation period T corresponds to a predetermined time specified in this disclosure.

[0084] The temperature of the heater core 55 obtained after switching to the second operating mode is essentially the same as the coolant temperature control data calculated in step S103. The isothermal time increases when the temperature difference is increased, where the temperature difference is the difference between the temperature of the heater core 55 after switching to the second operating mode and the temperature of the engine coolant as measured by the coolant temperature sensor 53 after switching to the second operating mode.

[0085] For this reason, the target restriction time T is extended if the difference between the coolant temperature control data calculated in step S103 and the engine coolant temperature detected by the coolant temperature sensor 53 after switching to the second operating mode increases. This allows the difference between the time at which the temperature of the heater core 55 becomes substantially equal to the engine coolant temperature detected by the coolant temperature sensor 53 and the time at which the target restriction time T ends to be reduced.

[0086] If the flow rate of the coolant flowing through circulation passage 51 decreases, the isothermal time is extended. Therefore, if the flow rate of the coolant circulating through circulation passage 51 decreases, the target restriction time T is extended based on information concerning the flow rate of the coolant circulating through circulation passage 51. This reduces the difference between the time at which the temperature of the heater core 55 becomes substantially equal to the coolant temperature detected by the coolant temperature sensor 53 and the time at which the target restriction time T ends.

[0087] As the airflow of blower 16 increases, the amount of heat absorbed from the engine coolant also increases, thus moderating the temperature rise of the engine coolant. Therefore, the airflow of blower 16 is calculated based on the speed of blower 16. As the airflow of blower 16 increases, the target limitation time T is extended. This reduces the difference between the time at which the temperature of the heater core 55 becomes substantially equal to the temperature of the engine coolant detected by the coolant temperature sensor 53 and the time at which the target limitation time T ends.

[0088] In an interior air operating mode for blowing the interior air heated by the heater core 55 into the vehicle interior, the amount of heat absorbed from the engine coolant is increased when the interior air temperature decreases, thus moderating the temperature increase of the engine coolant. Consequently, in interior air operating mode, when the interior air temperature detected by the coolant temperature sensor 53 decreases, the target limitation time T is extended. This reduces the difference between the time at which the temperature of the heater core 55 becomes substantially equal to the temperature of the engine coolant detected by the coolant temperature sensor 53 and the time at which the target limitation time T ends.

[0089] In an outside air operating mode for blowing outside air heated by the heater core 55 into the vehicle interior, the amount of heat absorbed from the engine coolant is increased when the outside air temperature decreases, thus moderating the temperature increase of the engine coolant. Consequently, in outside air operating mode, when the outside air temperature detected by the outside air sensor 72 decreases, the target limitation time T is extended. This reduces the difference between the time at which the temperature of the heater core 55 becomes substantially equal to the temperature of the engine coolant detected by the coolant temperature sensor 53 and the time at which the target limitation time T ends.

[0090] The processing then proceeds from step S106 to step S107. In order to measure a restriction time in step S107, which is the time elapsed since switching to the second operating mode, a timer for the restriction time is cleared and set to zero (0).

[0091] The processing then continues from step S107 to step S108. In step S108, a limited coolant temperature is calculated. Specifically, the limited coolant temperature is set to a lower temperature than the engine coolant temperature as measured by coolant temperature sensor 53. More precisely, the limited coolant temperature is defined as the coolant temperature control data calculated in step S103. The limited coolant temperature is used to suppress fluctuations in the coolant temperature control data when the engine coolant temperature is subject to significant variations.

[0092] The processing then proceeds from step S108 to step S109. In step S109, it is determined whether the constraint time exceeds the target constraint time T. If the constraint time is less than or equal to the target constraint time T, a negative decision is made in step S109, and the processing continues to step S110.

[0093] In step S110, the coolant temperature control data is calculated. Specifically, if a negative decision is made in step S109 because the constraint time is less than or equal to the target constraint time T, the restricted coolant temperature calculated in step S108 is set as the coolant temperature control data. Here, the restricted coolant temperature calculated in step S108 is the same as the coolant temperature control data calculated in step S103. Therefore, as in Fig.Figure 3 shows that the coolant temperature control data obtained while the first operating mode is set is the same as the coolant temperature control data obtained when the constraint time is less than or equal to the target constraint time T. Steps S106, S108, and S110 establish a second coolant temperature data calculation section.

[0094] The processing then proceeds from step S110 to step S111. To measure the constraint time in step S111, the constraint time is incremented. Consequently, the constraint time value is increased by one counter.

[0095] The processing then proceeds from step S111 to step S104. In step S104, a target operating value for the air conditioning control device, such as the blower 16, is calculated based on the coolant temperature control data calculated in step S110, and then a control signal corresponding to the calculated target operating value is output to the air conditioning control device.

[0096] If the operation of the internal combustion engine 50 continues next in the second operating mode, the negative decision is made in step S105, and then the processing continues to step S109.

[0097] If the constraint time is less than or equal to the target constraint time T, processing continues via steps S110 and S111 to step S104. In step S104, the control signal is output to the air conditioning control device, as mentioned above.

[0098] As mentioned above, until the target limitation time T has elapsed from the switch to the second operating mode, a temperature lower than the engine coolant temperature detected by the coolant temperature sensor 53 is set as the coolant temperature control data. This makes it possible to reduce the difference between the coolant temperature control data and the actual temperature of the heater core 55. Therefore, the control of the air volume, blown air temperature, and similar parameters can be carried out appropriately, thus improving comfort.

[0099] Furthermore, until the target restriction time T has elapsed since switching to the second operating mode, fluctuations in the coolant temperature control data are suppressed, thereby suppressing fluctuations in the air volume and the occurrence of oscillation in different control modes.

[0100] However, if the restriction time exceeds the target restriction time T, a positive decision is made in step S109 and processing continues to step S112.

[0101] In step S112, the coolant temperature control data is calculated. If the restriction time exceeds the target restriction time T, it is estimated that the temperature of the heater core 55 will become essentially equal to the coolant temperature detected by the coolant temperature sensor 53. Therefore, in step S112, the engine coolant temperature detected by the coolant temperature sensor 53 is set as the coolant temperature control data.

[0102] The processing then continues from step S112 to step S104. In step S104, a target operating value of the air conditioning control device, such as the blower 16, is calculated based on the coolant temperature control data calculated in step S112, and then a control signal corresponding to the calculated target operating value is output to the air conditioning control device.

[0103] According to the present embodiment, while the first operating mode is set, the coolant temperature control data is calculated based on the engine coolant temperature detected by the coolant temperature sensor 53 when the internal combustion engine 50 is started. This makes it possible to reduce the difference between the coolant temperature control data and the actual temperature of the heater core 55. Therefore, the control of the air volume, blown air temperature, and similar parameters can be appropriately implemented, thereby improving comfort.

[0104] Until the target limitation time T has elapsed since switching to the second operating mode, the temperature lower than the engine coolant temperature detected by the coolant temperature sensor 53 is set as the coolant temperature control data. This makes it possible to reduce the difference between the coolant temperature control data and the actual temperature of the heater core 55. Therefore, the control of air volume, blown air temperature, and similar parameters can be appropriately implemented, thus improving comfort.

[0105] Furthermore, until the target restriction time T has elapsed after switching to the second operating mode, fluctuations in the coolant temperature control data are suppressed, thereby suppressing fluctuations in the air volume and the occurrence of oscillation in different control modes.

[0106] (First Modification) In step S102 of the embodiment described above, the climate control unit 61 sets the engine coolant temperature detected by the coolant temperature sensor 53 at the start of the internal combustion engine 50 as the estimated core heating temperature. However, in step S102, the climate control unit 61 can instead correct the engine coolant temperature detected by the coolant temperature sensor 53 at the start of the internal combustion engine 50 and set the corrected temperature as the estimated core heating temperature. The climate control unit 61 performs the correction such that if the outside air temperature detected by the outside air sensor 72 is higher at the start of the internal combustion engine 50, the temperature after the correction will be higher.

[0107] (Second Modification) In step S108 of the embodiment described above, the climate control unit 61 sets the coolant temperature control data calculated in step S103 as the limited coolant temperature. However, in step S108, the climate control unit 61 can correct the coolant temperature control data calculated in step S103 so that the data increase as time passes after switching to the second operating mode. The climate control unit 61 can then set the coolant temperature control data obtained after the correction as the limited coolant temperature. In this modification as well, the limited coolant temperature is set as a temperature lower than the engine coolant temperature detected by the coolant temperature sensor 53.

[0108] (Third modification) In the third modification, the climate control unit 61 can decrease the amount of change per unit time in the coolant temperature control data when the throughput of the engine coolant circulating through the circulation passage 51 decreases.

[0109] (Fourth modification) In the fourth modification, the air conditioning control 61 can decrease the amount of change per unit of time in the coolant temperature control data when the blow volume of the blower 16 increases.

[0110] (Fifth modification) In the fifth modification, the climate control 61 in indoor air operating mode can decrease the amount of change per unit of time in the coolant temperature control data when the air temperature detected by the indoor air sensor 71 decreases.

[0111] (Sixth modification) In the sixth modification, the air conditioning control 61 in outdoor air operating mode can decrease the amount of change per unit of time in the coolant temperature control data when the outdoor air temperature detected by the outdoor air sensor 72 decreases. (Other embodiments)

[0112] The present disclosure is not limited to the embodiments described above, and various modifications and changes can be made to the embodiments.

[0113] It is obvious that in the aforementioned embodiment, the included elements are not necessarily essential unless they are specified as otherwise essential, apart from when they are clearly considered essential in principle, and the like.

[0114] When, in the aforementioned embodiment, reference is made to specific numbers of a component, which include the number, a numerical value, a quantity, an area and the like, the component in the embodiments should not be limited to the specific number unless otherwise specified, in particular, as essential, and apart from that, unless it is limited to the specific number in principle.

[0115] Even if the aforementioned embodiment refers to the shape and positional relationship of components and the like, the component in the embodiment should not be limited to such a shape, positional relationship or the like unless otherwise specified and apart from when it is obviously limited to the specific shape, positional relationship and the like as a matter of principle.

[0116] The aforementioned embodiment and modifications may be combined as necessary, except where their combination appears obviously impossible.

Claims

[1] Air conditioning system for a vehicle, which performs the climate control of a vehicle interior, comprising: a blower (16) that blows air into the vehicle interior; a circulation passage (51) through which a coolant circulates to cool an internal combustion engine (50); a heating core (55) which is arranged in the circulation passage (51) and is designed to heat air that is to be blown into the vehicle interior using the coolant; a diversion passage (56) connected to the circulation passage (51), wherein the diversion passage (56) is designed to cause the coolant to circulate while bypassing the heating core (55); a switching valve (54) which is arranged to switch between a first operating mode in which the coolant flowing from the internal combustion engine (50) flows through the diversion passage (56) and returns to the internal combustion engine (50) while bypassing the heating core (55) and a second operating mode in which the coolant flowing from the internal combustion engine (50) flows to the heating core (55); a coolant temperature sensor (53) that detects the temperature of the coolant at a part of the circulation passage (51) through which the coolant flows in both the first operating mode and the second operating mode; a control unit (61) for controlling the operation of the blower (16) based on coolant temperature control data; a first coolant temperature data calculation section (S102, S103) which is set up to calculate the coolant temperature control data in the first operating mode; and a second coolant temperature data calculation section (S106, S108, S110) which is set up to calculate the coolant temperature control data until a predetermined time has elapsed since switching to the second operating mode, wherein the first coolant temperature data calculation section (S102, S103) calculates the coolant temperature control data based on a coolant temperature detected by the coolant temperature sensor (53) when the internal combustion engine (50) is started, and the second coolant temperature data calculation section (S106, S108, S110) as the coolant temperature control data sets a temperature that is lower than the coolant temperature detected by the coolant temperature sensor (53). [2] Air conditioning system for a vehicle according to claim 1, wherein the first coolant temperature data calculation section (S102, S103) defines as the coolant temperature control data a temperature of the coolant which is detected by the coolant temperature sensor (53) when the internal combustion engine (50) is started. [3] Air conditioning system for a vehicle according to claim 1, further comprising: an outdoor air sensor (72) which detects the temperature of outdoor air, wherein The first coolant temperature data calculation section (S102, S103) corrects a coolant temperature detected by the coolant temperature sensor (53) when the internal combustion engine (50) is started, so that the detected coolant temperature becomes higher when the outside air temperature detected by the outside air sensor (72) becomes higher when the internal combustion engine (50) is started, and then sets the corrected coolant temperature as the coolant temperature control data. [4] Air conditioning system for a vehicle according to any one of claims 1 to 3, wherein the second coolant temperature data calculation section (S106, S108, S110) specifies the coolant temperature control data calculated by the first coolant temperature data calculation section (S102, S103) as the coolant temperature control data for the second coolant temperature data calculation section (S106, S108, S110). [5] Air conditioning system for a vehicle according to any one of claims 1 to 3, wherein the second coolant temperature data calculation section (S106, S108, S110) increases a value of the coolant temperature control data as the time after switching to the second operating mode increases. [6] Air conditioning system for a vehicle according to any one of claims 1 to 5, wherein the second coolant temperature data calculation section (S106, S108, S110) extends the predetermined time when the difference between the coolant temperature control data calculated by the first coolant temperature data calculation section (S102, S103) after switching to the second operating mode and a coolant temperature detected by the coolant temperature sensor (53) after switching to the second operating mode increases. [7] Air conditioning system for a vehicle according to any one of claims 1 to 5, wherein the second coolant temperature data calculation section (S106, S108, S110) extends the predetermined time when the flow rate of the coolant circulating through the circulation passage (51) decreases. [8] Air conditioning system for a vehicle according to one of claims 1 to 5, wherein the second coolant temperature data calculation section (S106, S108, S110) extends the specified time when the blow quantity of the blower (16) increases. [9] Air conditioning system for a vehicle according to any one of claims 1 to 5, further comprising: an interior air sensor (71) that detects the temperature of the vehicle interior, wherein The second coolant temperature data calculation section (S106, S108, S110) extends the specified time if the temperature of the vehicle interior, as detected by the interior air sensor (71), decreases in an interior air operating mode in which air inside the vehicle interior is heated by the heater core (55) to be blown into the vehicle interior. [10] Air conditioning system for a vehicle according to any one of claims 1 to 5, further comprising: an outdoor air sensor (72) which detects the temperature of the outdoor air, wherein The second coolant temperature data calculation section (S106, S108, S110) extends the specified time if the temperature of the outside air detected by the outside air sensor (72) decreases in an outside air operating mode in which outside air is heated by the heater core (55) to be blown into the vehicle interior. [11] Air conditioning system for a vehicle according to claim 5, wherein the second coolant temperature data calculation section (S106, S108, S110) reduces a change quantity per unit time in the coolant temperature control data when a flow rate of the coolant circulating through the circulation passage (51) decreases. [12] Air conditioning system for a vehicle according to claim 5, wherein the second coolant temperature data calculation section (S106, S108, S110) reduces a change quantity per unit of time in the coolant temperature control data when a blow quantity of the blower (16) increases. [13] Air conditioning system for a vehicle according to claim 5, further comprising: an interior air sensor (71) that detects the temperature of the vehicle interior, wherein The second coolant temperature data calculation section (S106, S108, S110) reduces the amount of change per time in the coolant temperature control data when the temperature of the vehicle interior, as detected by the interior air sensor (71), decreases in an interior air operating mode in which air inside the vehicle interior is heated by the heater core (55) to be blown into the vehicle interior. [14] Air conditioning system for a vehicle according to claim 5, further comprising: an outdoor air sensor (72) which detects the temperature of the outdoor air, wherein The second coolant temperature data calculation section (S106, S108, S110) reduces the amount of change per time in the coolant temperature control data when the temperature of the outside air detected by the outside air sensor (72) decreases in an outside air operating mode in which outside air is heated by the heater core (55) to be blown into the vehicle interior.

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