JP2013203254A - Air conditioning system for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioning system for an electric vehicle capable of preventing damages due to an abnormal high temperature of a PTC heater and around the same without additionally providing a temperature sensor.SOLUTION: When abnormal conditions of an electric pump 11 are detected based on the real number of rotation of the electric pump 11, the electric pump 11 is stopped. When the electric pump 11 is stopped, hot water stagnates in a hot water circulation path 9. At this point, when electrifying to a PTC heater 12 is continued, the temperature of the PTC heater 12 and the temperature near the same rise abnormally. In order to prevent such an abnormal temperature rise, when the real number of rotation of the electric pump 11 lowers to a predetermined number or less, electrifying to the PTC heater 12 is stopped. When the water feeding ability by the electric pump 11 lowered and the hot water stagnates in the hot water circulation path 9, the temperature of the hot water to be supplied to a heater core 5 quickly rises. Then, in the case wherein a temperature rise width of the temperature detected by a temperature sensor 24 in a predetermined time is a predetermined value or more, electrifying to the PTC heater 12 is stopped.

Description

  The present invention relates to an air conditioning system for an electric vehicle.

  In an automobile (engine automobile) using an engine as a drive source, engine cooling water is supplied to a heater core for warming air blown by a blower, so that exhaust heat of the engine is used for heating.

  Since an electric vehicle is not equipped with an electric vehicle, the exhaust heat of the engine (cooling water) cannot be used for heating. Therefore, in an electric vehicle air conditioning system, for example, a PTC (Positive Temperature Coefficient) heater is provided on the hot water circulation path as a heat source for heating water (hot water). Then, the water pump is driven to circulate the hot water in the hot water circulation path, and the hot water heated by the PTC heater is supplied to the heater core through the hot water circulation path, thereby heating the heater core.

  In such an air conditioning system, there is a problem of emptying the PTC heater. That is, if energization to the PTC heater is continued when there is no hot water in the hot water circuit due to leakage of hot water from the hot water circuit, etc., the PTC heater becomes abnormally hot and the PTC heater and its surrounding parts become There is a risk of damage.

  Therefore, it is conceivable to provide a temperature sensor for detecting the temperature of the PTC heater, and to stop energization of the PTC heater when the temperature of the PTC heater becomes abnormally high. Also, temperature sensors are provided near the inlet and the outlet of the hot water in the PTC heater, respectively, and if the difference in temperature detected by these temperature sensors is out of a predetermined range, it is determined that an abnormality such as emptying of the PTC heater has occurred. Then, it is conceivable to stop energization of the PTC heater.

JP 2010-221772 A JP 2011-16489 A

  However, in any method, it is necessary to additionally provide a temperature sensor separately from the temperature sensor for energization control (heater core temperature control) to the PTC heater, which increases the cost of the air conditioning system. .

  The objective of this invention is providing the air-conditioning system for electric vehicles which can prevent the damage by the abnormal high temperature of a PTC heater and its periphery, without providing an additional temperature sensor.

  In order to achieve the above object, an air conditioning system for an electric vehicle according to the present invention includes an air conditioning duct through which blast supplied to a passenger compartment circulates, a hot water passage, and a water for circulating hot water through the hot water passage. A pump, a PTC heater that heats the hot water flowing through the hot water flow path, a heater core that is supplied with the hot water flowing through the hot water flow path and that heats the air flowing through the air conditioning duct, and the water pump An abnormality of the water pump based on a rotational speed detecting means for detecting the rotational speed, a hot water temperature detecting means for detecting a temperature of hot water supplied to the heater core, and an actual rotational speed detected by the rotational speed detecting means. An abnormality detecting means for detecting the abnormality, and an abnormality stopping means for stopping the water pump when an abnormality of the water pump is detected by the abnormality detecting means; A first energization stop means for stopping energization of the PTC heater and a predetermined temperature detected by the hot water temperature detection means when the actual rotation speed detected by the rotation speed detection means is less than or equal to a predetermined rotation speed; Second energization stopping means for stopping energization of the PTC heater when a temperature rise width in time is equal to or greater than a predetermined value.

  When the water pump is driven, warm water flows through the warm water flow path. Further, when power is supplied to the PTC heater, the PTC heater generates heat. The warm water is heated by the heat generated from the PTC heater, and the heater core is heated by the warm water. At this time, when the air flowing through the air conditioning duct passes through the heater core, the air becomes hot air.

  When an abnormality of the water pump is detected based on the actual rotational speed of the water pump, the water pump is stopped.

  When the water pump is stopped, warm water stays in the warm water flow path. At this time, if energization to the PTC heater is continued, the temperature of the PTC heater and the vicinity thereof abnormally rises. In order to prevent this, when the actual rotational speed of the water pump falls below a predetermined rotational speed, energization to the PTC heater is stopped. As a result, damage due to abnormally high temperatures in the PTC heater and its surroundings can be prevented.

  For example, when air biting of the water pump occurs, the water supply capability of the water pump is reduced, and hot water stays in the hot water flow path. At this time, since the actual rotational speed of the water pump does not decrease below the predetermined rotational speed, the PTC heater may continue to be energized. When energization of the PTC heater is continued, the hot water staying in the hot water flow path rises to a high temperature. Then, when the high temperature is transmitted to the vicinity of the heater core, the temperature detected by the temperature detecting means for detecting the temperature of the hot water supplied to the heater core increases rapidly.

  Then, when the temperature rise width in the predetermined time of the temperature detected by the hot water temperature detecting means is a predetermined value or more, the energization to the PTC heater is stopped. Thereby, it can prevent that a PTC heater and the temperature of the vicinity raise abnormally. As a result, damage due to abnormally high temperatures in the PTC heater and its surroundings can be prevented.

  And the temperature detection means for detecting the temperature of the warm water supplied to a heater core is normally provided for the energization control (temperature control of a heater core) to a PTC heater. Therefore, it is not necessary to additionally provide a new temperature detecting means in order to prevent damage due to abnormally high temperatures in the PTC heater and its surroundings.

  According to the present invention, damage due to abnormally high temperatures in the PTC heater and its surroundings can be prevented without providing additional temperature detection means.

FIG. 1 is a diagram schematically showing the configuration of an air conditioning system according to an embodiment of the present invention. FIG. 2 is a flowchart showing the flow of abnormal pump stop processing. FIG. 3 is a flowchart showing the flow of the PTC heater fail-safe process. FIG. 4 is a graph showing changes in hot water temperature.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically showing the configuration of an air conditioning system according to an embodiment of the present invention.

  The air conditioning system 1 is an air conditioning system for an electric vehicle using a motor (not shown) as a drive source. The air-conditioning system 1 includes an air-conditioning duct 2, a blower 3 that generates airflow that flows through the air-conditioning duct 2 toward the vehicle interior, an evaporator 4 that cools airflow that flows through the air-conditioning duct 2, and airflow that flows through the air-conditioning duct 2. And a heater core 5 for heating.

  The evaporator 4 is disposed in the air conditioning duct 2. A refrigerant circulation path 6 is connected to the evaporator 4. An electric compressor 7 and a condenser 8 are interposed in the refrigerant circulation path 6.

  When the electric compressor 7 is driven, the refrigerant compressed by the electric compressor 7 is supplied to the capacitor 8. In the condenser 8, the compressed refrigerant is cooled, so that the refrigerant is liquefied. A receiver (not shown) and an expansion valve (not shown) are provided downstream of the condenser 8 in the refrigerant flow direction. The refrigerant flowing out from the condenser 8 is supplied to the receiver. In the receiver, the vaporized refrigerant and the liquefied refrigerant are separated. Then, only the liquefied refrigerant is sent from the receiver to the expansion valve, and the liquefied refrigerant is injected from the expansion valve to the evaporator 4, thereby cooling the evaporator 4.

  The air blown from the blower 3 is cooled by passing through the evaporator 4, becomes cold air, and flows in the air conditioning duct 2 toward the vehicle interior.

  The heater core 5 is disposed in the vehicle interior side of the evaporator 4 in the air conditioning duct 2. A warm water circulation path 9 is connected to the heater core 5. A reservoir tank 10, an electric pump 11, and a PTC (Positive Temperature Coefficient) heater 12 are interposed in the hot water circulation path 9.

  The reservoir tank 10 stores water (hot water). When the electric pump 11 is driven, water is pumped from the reservoir tank 10, and the water circulates through the hot water circulation path 9. The PTC heater 12 is disposed downstream of the electric pump 11 in the flow direction of hot water and upstream of the heater core 5 in the flow direction. The water circulating in the hot water circulation path 9 is heated by the PTC heater 12 to become hot water and is supplied to the heater core 5. Thereby, the heater core 5 is heated with warm water.

  In the air conditioning duct 2, an air mix damper 13 is provided between the evaporator 4 and the heater core 5. Depending on the position of the air mix damper 13, the air flow rate that passes through the heater core 5 and the air flow rate that does not pass through the heater core 5 are adjusted. The air that passes through the heater core 5 is heated by the heater core 5. By mixing the air that has passed through the heater core 5 and the air that has not passed through the heater core 5, the air-conditioned air has an appropriate temperature, and the air-conditioned air flows toward the vehicle interior.

  A defroster outlet 14, a face outlet 15 and a foot outlet 16 are formed at the outlet of the air conditioning duct 2. The conditioned air passing through the defroster outlet 14 is blown out toward the windshield and the front side glass, for example. The conditioned air passing through the face outlet 15 is blown out toward the upper part of the driver seat and the passenger seat, for example. The conditioned air passing through the foot outlet 16 is blown out below the driver seat and the passenger seat, for example. In the air conditioning duct 2, air outlet switching dampers (not shown) for opening and closing the defroster air outlet 14, the face air outlet 15, and the foot air outlet 16 are provided.

  An inlet switching damper 17 is provided at the inlet of the air conditioning duct 2 to switch between introduction of outside air that takes air outside the passenger compartment into the air conditioning duct 2 and circulation of internal air that takes air inside the passenger compartment into the air conditioning duct 2. ing.

  The air conditioning system 1 includes an ECU (electronic control unit) 21 having a configuration including a CPU and a memory.

  The ECU 21 is connected to the blower 3, the electric compressor 7, the electric pump 11, the air mix damper 13, and the suction port switching damper 17 as control targets. A relay 22 for turning on / off the energization of the PTC heater 12 is connected as a control target. Further, the ECU 21 is connected with a rotation speed sensor 23 for detecting the rotation speed (actual rotation speed) of the electric pump 11 and a temperature sensor 24 for detecting the temperature of hot water supplied from the hot water circulation path 9 to the heater core 5. ing.

  The ECU 21 controls the driving of the electric pump 11 based on the rotation speed detected by the rotation speed sensor 23 so that the rotation speed of the electric pump 11 matches the target rotation speed. Further, the ECU 21 controls energization of the PTC heater 12 based on the temperature detected by the temperature sensor 24 so that the temperature of the hot water supplied to the heater core 5 matches the target temperature. Further, the ECU 21 performs a pump abnormal stop process and a PTC heater fail-safe process, which will be described below, based on the rotational speed detected by the rotational speed sensor 23 and the temperature detected by the temperature sensor 24.

  FIG. 2 is a flowchart showing the flow of abnormal pump stop processing.

  While the electric pump 11 is being driven, the ECU 21 repeatedly executes the pump abnormal stop process shown in FIG.

  In the abnormal pump stop process, the rotational speed of the electric pump 11 detected by the rotational speed sensor 23 is constantly monitored while the electric pump 11 is being driven. When the rotation speed detected by the rotation speed sensor 23 and the target rotation speed of the electric pump 11 are more than a certain degree and the state continues for a predetermined time or more, an abnormality has occurred in the electric pump 11. Is determined (abnormality of the electric pump 11 is detected) (YES in step S1).

  If it is determined that an abnormality has occurred in the electric pump 11, the electric pump 11 is stopped (step S2).

  After the electric pump 11 is stopped, pump return control is performed to check whether or not the abnormality of the electric pump 11 has been resolved (step S3). In the pump return control, the target rotational speed of the electric pump 11 is set to a predetermined rotational speed, and after the drive command is output from the ECU 21 to the electric pump 11 for a predetermined time t2, the drive command is stopped, and thereafter A drive command is output over a predetermined time t2. That is, a command for intermittently driving the electric pump 11 is output from the ECU 21 to the electric pump 11. In response to this, when the rotational speed detected by the rotational speed sensor 23 rises above the return threshold, it is determined that the abnormality of the electric pump 11 has been resolved, and normal control of the electric pump 11 is resumed. On the other hand, if the rotational speed detected by the rotational speed sensor 23 does not rise above the return threshold value, it is determined that the abnormality of the electric pump 11 has not been resolved.

  FIG. 3 is a flowchart showing the flow of the PTC heater fail-safe process.

  In parallel with the pump abnormal stop process, the ECU 21 repeatedly executes the PTC heater fail-safe process shown in FIG.

  In the PTC heater fail-safe process, first, it is checked whether or not the rotational speed of the electric pump 11 detected by the rotational speed sensor 23 is equal to or lower than a predetermined rotational speed (for example, 500 rpm) (step S11).

  When the rotation speed detected by the rotation speed sensor 23 is equal to or less than the predetermined rotation speed (YES in step S11), it is determined that the electric pump 11 is stopped. Then, the relay 22 is turned off (step S12), the energization to the PTC heater 12 is stopped, and the PTC heater failsafe process is ended.

  If the rotational speed detected by the rotational speed sensor 23 is higher than the predetermined rotational speed (NO in step S11), then, the temperature increase rate detected by the temperature sensor 24, that is, hot water supplied to the heater core 5 It is determined whether or not the temperature increase width at a predetermined time is equal to or greater than a predetermined value (step S13).

  If the temperature rise is equal to or greater than the predetermined value (YES in step S13), the relay 22 is turned off (step S12), the energization to the PTC heater 12 is stopped, and the PTC heater failsafe process is ended. .

  If the temperature rise is less than the predetermined value (NO in step S13), the continuous drive time of the electric pump 11 is longer than the time t2 when the drive command is output from the ECU 21 in the pump return control (> t2). It is determined whether or not this is the case (step S14).

  Then, until the continuous drive time of the electric pump 11 reaches time t1 (NO in step S14), the relay 22 is turned off (step S12).

  When the continuous drive time of the electric pump 11 reaches time t1 (YES in step S14), it is determined that the electric pump 11 is operating normally, the relay 22 is turned on (step S15), and the PTC heater failsafe Processing is terminated.

  As described above, when the electric pump 11 is driven, hot water flows through the hot water circulation path 9. Further, when power is supplied to the PTC heater 12, the PTC heater 12 generates heat. The warm water is heated by the heat generated from the PTC heater 12, and the heater core 5 is heated by the warm water. At this time, when the air flowing through the air conditioning duct 2 passes through the heater core 5, the air becomes warm air.

  When an abnormality of the electric pump 11 is detected based on the rotation speed of the electric pump 11 detected by the rotation speed sensor, the electric pump 11 is stopped.

  When the electric pump 11 is stopped, warm water stays in the warm water circulation path 9. At this time, if energization to the PTC heater 12 is continued, the temperature of the PTC heater 12 and the vicinity thereof abnormally rises. In order to prevent this, energization of the PTC heater 12 is stopped when the rotational speed of the electric pump 11 falls below a predetermined rotational speed. As a result, damage due to abnormally high temperatures in the PTC heater 12 and its surroundings can be prevented.

  When the electric pump 11 is operating normally (when hot water is flowing through the hot water circulation path 9), when the relay 22 is switched from off to on and energization of the PTC heater 12 is started. 4, the temperature detected by the temperature sensor 24, that is, the temperature of the hot water supplied to the heater core 5 rises relatively slowly, as indicated by the alternate long and short dash line in FIG.

  On the other hand, for example, when air biting of the electric pump 11 occurs, the water supply capability of the electric pump 11 decreases, and hot water stays in the hot water circulation path 9. At this time, if energization to the PTC heater 12 is continued, the hot water staying in the hot water circulation path 9 rises to a high temperature. When the high temperature is transmitted to the vicinity of the heater core 5, the temperature detected by the temperature sensor 24, that is, the temperature of the hot water supplied to the heater core 5 rapidly increases as shown by the solid line in FIG. 4.

  Therefore, when the temperature increase width of the temperature detected by the temperature sensor 24 for a predetermined time is equal to or greater than a predetermined value, the energization to the PTC heater 12 is stopped. Thereby, it can prevent that the temperature of the PTC heater 12 and its vicinity rises abnormally. As a result, damage due to abnormally high temperatures in the PTC heater 12 and its surroundings can be prevented.

  The temperature sensor 24 for detecting the temperature of the hot water supplied to the heater core 5 is usually provided for energization control (temperature control of the heater core) to the PTC heater 12. Therefore, it is not necessary to add a new temperature sensor in order to prevent damage due to abnormally high temperatures in the PTC heater 12 and its surroundings.

  As mentioned above, although one Embodiment of this invention was described, it is possible to give a various design change to the above-mentioned structure in the range of the matter described in the claim.

1 Air conditioning system (air conditioning system for electric vehicles)
2 Air conditioning duct 5 Heater core 9 Hot water circulation path (hot water flow path)
10 Gas-liquid separation tank 11 Electric pump (water pump)
12 PTC heater 21 ECU (abnormality detection means, abnormal stop means, first energization stop means, second energization stop means)
23 Rotational speed sensor (Rotational speed detection means)
24 Temperature sensor (hot water temperature detection means)

Claims (1)

An air conditioning duct through which the air supplied to the passenger compartment circulates;
A hot water channel,
A water pump for circulating hot water through the hot water flow path;
A PTC heater for heating hot water flowing through the hot water flow path;
A heater core for supplying hot water flowing through the hot water flow path and heating the air flowing through the air conditioning duct;
A rotational speed detection means for detecting an actual rotational speed of the water pump;
Hot water temperature detecting means for detecting the temperature of hot water after being heated by the PTC heater and before being supplied to the heater core;
An abnormality detecting means for detecting an abnormality of the water pump based on the actual rotational speed detected by the rotational speed detecting means;
An abnormality stopping means for stopping the water pump when the abnormality of the water pump is detected by the abnormality detecting means;
First energization stop means for stopping energization of the PTC heater when the actual rotation speed detected by the rotation speed detection means is equal to or less than a predetermined rotation speed;
An air conditioning system for an electric vehicle, comprising: a second energization stop unit that stops energization of the PTC heater when a temperature rise width of the temperature detected by the hot water temperature detection unit is not less than a predetermined value. .

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