JP2014109209A - Vehicle with air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle mounted with an air conditioner having a compressor to be driven by engine power, for enabling the correction of an idle speed without giving an unpleasant feel to an occupant, even when the air conditioner is turned on at starting.SOLUTION: When the air conditioner is turned on at starting, stopping the drive of a compressor 7 without stopping a blowing fan 11 of the air conditioner sets an engine into an unloaded state. In this state, the revolving speed and the load of the engine are detected, and an adequate idle speed is computed on the basis of the detected value. Even when the compressor 7 is stopped, air is continuously blown, and so there is no case that the occupant erroneously recognizes a trouble of the air conditioner. When the compressor 7 is stopped, the air conditioner does not work well, but the occupant does not often recognize the fact right after starting.

Description

  The present invention relates to a vehicle equipped with an air conditioner driven by an internal combustion engine, and is particularly characterized by an idle speed learning function.

  The internal combustion engine mounted on the vehicle has an idle speed that is set as a standard at the time of shipment, but the optimal idle speed varies depending on the engine temperature, oil temperature, individual differences in the throttle valve, fuel differences, etc. is there. Therefore, an idle speed controller (ISC), which is a means for correcting the idle speed, is incorporated into the ECU (engine control unit), for example, several times after starting or after shipment, or after replacing the battery, By detecting the actual idle speed in a load state and calculating whether or not this speed is optimum in relation to the load, the idle speed is lowered or increased to the optimum speed or corrected. That is, the idle speed is learned again every time the engine is started. The no-load state includes both the case where the alternator is driven and the case where the alternator is not driven.

  When correcting the idling engine speed, the engine speed must be detected when the engine is unloaded, but when the air conditioner compressor is driven by engine power, the air conditioner should be Since it is often turned on (or started with the air conditioner turned on), there is often no chance of correcting the idling speed.

  If there is no opportunity for correction (learning), the reference rotational speed set at the time of shipment is inevitably returned, but the reference rotational speed at the time of shipment is mostly set higher with a margin. For this reason, in reality, idling is performed at a high rotational speed even though a low rotational speed is sufficient, resulting in a phenomenon that fuel consumption deteriorates.

  In this regard, Patent Document 1 describes that an idle learning environment (no-load state) is created by forcibly stopping an air conditioner.

JP 09-68085 A

  From the standpoint of a person riding in the vehicle, if the air conditioner suddenly turns off even though the air conditioner switch is ON, most people misunderstand that the air conditioner is malfunctioning and feel uncomfortable. Therefore, although patent document 1 can learn idle rotation speed also in the environment which uses an air-conditioner, there exists a problem with a passenger's misunderstanding and discomfort.

  The present invention has been made to improve the present situation, and enables the correction (learning) of the idle speed to be accurately performed without causing discomfort or misunderstanding to the passenger even when using an air conditioner. It is for the purpose.

  In the present invention, an internal combustion engine that detects the engine speed in a no-load state and corrects the idle speed, and an air conditioner including a compressor that operates when the refrigerant pressure or the evaporator temperature falls below a predetermined value are mounted. In the vehicle driven by the internal combustion engine, the compressor of the air conditioner is in an idle operation after the start of the internal combustion engine and when the air conditioner is ON, the refrigerant pressure or the evaporator temperature of the air conditioner is equal to or lower than a predetermined value. Even if the pressure decreases, the idle rotation speed is corrected by maintaining the air flow and setting the no-load operation without driving the compressor.

  Note that the oil pump and the water pump are driven by engine power (crankshaft), but since they are always rotating during operation of the internal combustion engine, they are not regarded as loads. Further, since the alternator is often driven even in the idling state, the idling speed is often detected based on the state in which the idling is driven. In other words, no load means that the fluctuating load is hardly acting. Therefore, the idling speed is the lowest that can drive the oil pump and the water pump (and the alternator) without causing engine slur. It can be said that the rotation speed.

  The compressor of an air conditioner does not always operate, but operates when the refrigerant pressure or the evaporator temperature falls to the lower limit, and stops when it rises to the upper limit. Therefore, there is a time during which the compressor is stopped even during operation of the air conditioner. And in this invention, on condition that the load element like an ON / OFF type auxiliary machine is not driven and used, by making an engine into a no-load state without driving a compressor, idling speed Correction can be performed accurately.

  When setting the idling speed when the alternator is driven, for example, when the head unit is turned on or a heating device is used from the power source in the vehicle, the alternator is used to recover the consumed power. As the workload increases, the load on the engine increases. Therefore, it is preferable to set a state in which these are not used to a no-load state for those that cause engine load fluctuations through fluctuations in the work of the alternator, such as lighting of a headlight.

  And since the airflow is maintained rather than turning off the entire air conditioner, the passenger will not think that the air conditioner has failed even if the compressor is not driven, and will not give people misunderstanding or discomfort . Also, even if the refrigerant pressure or evaporator temperature falls below the lower limit, if the compressor does not operate, the effectiveness of the air conditioner will deteriorate, but this is a temporary phenomenon that occurs only for a short time, and when the engine is started Since the temperature inside the vehicle is high and the effectiveness of the air conditioner is not good, there are many cases where the passenger is not aware of the effect of the air conditioner.

  As described above, according to the present invention, even when the air conditioner has been turned on from the time of starting, it is possible to accurately correct the idling speed without causing discomfort or misunderstanding to the passenger. Since the compressor is stopped for a long time as described above, it is also possible to finish the correction of the idle speed before the compressor stops operating and before the refrigerant pressure or the evaporator temperature falls to the lower limit. In this case, there is no problem of a decrease in the effectiveness of the air conditioner.

It is a schematic diagram which shows the structure of an internal combustion engine. It is a flowchart which shows an example of control.

(1). Outline of automobile Next, an embodiment of the present invention will be described with reference to the drawings. First, an outline will be described with reference to FIG. An engine room 1 is formed in the front part of the vehicle body, and an engine body 2 having a cylinder block and a cylinder head as main elements is disposed in a slightly rearward part of the engine room 1 with a crankshaft as a laterally long side. Arranged in a standing position.

  The engine body 2 is arranged close to one side of the engine room 1 (left side in the figure, right side when viewed from the driver). A transmission 3 such as a CVT system is provided on the right side of the left and right side surfaces in the figure. It is attached. A radiator 5 having a driving fan 4 is disposed in front of the transmission 3 in the engine room 1, and a condenser 6 of an air conditioner is disposed in front of the radiator 5.

  The air conditioner includes a compressor 7, a reservoir tank 8, and an evaporator (evaporator) 9 in addition to the condenser 6. Needless to say, the refrigerant compressed by the compressor 7 is cooled and liquefied by the condenser 6, enters the evaporator 9 from the expansion valve 10 via the reservoir tank 8, and is evaporated by the evaporator 9 to cool the room. (Heat exchange) is performed, and the vaporized refrigerant returns to the compressor 7. The reservoir tank 8 collects the refrigerant that has not been liquefied.

  The evaporator 9 is exposed to the air blown from the electric blower fan (blower) 11, and the heat of the wind sent from the blower fan is absorbed by the evaporator 9, so that the blown air is cooled and blown out into the vehicle interior 12. The If the air blowing amount of the blower fan 11 is strong, the amount of heat exchange of the evaporator 9 also increases. Therefore, the amount and strength of the cold air blown into the vehicle increases, and the refrigerant pressure drop (or evaporator temperature drop) also becomes significant. .

  The vehicle interior 12 and the engine room 1 are partitioned by a partition wall 13. A dashboard 14 is provided behind the partition wall 13, and the evaporator 9 and the blower fan 11 are built in the dashboard 14. The dashboard 14 is provided with an air conditioner switch (knob) 15 for ON / OFF of the air conditioner and air volume adjustment. Reference numeral 16 denotes a handle.

  In the present invention, the compressor 7 of the air conditioner is driven by the power of the internal combustion engine. That is, a chain cover 18 that covers the valve drive mechanism drive chain is provided on the side opposite to the transmission 3 in the engine body, and the compressor 7 is driven by the accessory drive belt 19 disposed outside the chain cover 18. Yes. The accessory drive belt 19 is wound around a main pulley 20 fixed to the crankshaft, and the alternator 20 is also driven by the accessory drive belt 19.

  The compressor 7 of the air conditioner includes an electromagnetic clutch 21, and the power transmission from the accessory drive belt 19 is interrupted by turning on and off the electromagnetic clutch 19. Note that the alternator 20 has a power change according to the power used, but a power meter is indicated by reference numeral 22 for convenience.

  An automobile is provided with an ECU (engine control unit) 23 that controls the engine as an example of a control device, and the temperature of the evaporator 9 of the air conditioner (more precisely, the cold air that is ejected from the evaporator 9 is controlled). A temperature sensor 24 that detects the temperature or the temperature of the refrigerant in the evaporator 9, an air conditioner switch 15, a rotational speed sensor 25 that detects the rotational speed of the engine, a load sensor (torque sensor) 26 that detects the engine load, and an accelerator pedal 27. A pedal sensor 28 that detects the amount of depression is electrically connected. The electromagnetic clutch 21 of the compressor 7 in the air conditioner, the switch 23 of the alternator 20, and the blower fan 11 of the air conditioner are also turned ON / OFF by an instruction from the ECU 25.

(2). Control Mode Next, an example of control will be described with reference to the flowchart of FIG. This embodiment is based on the assumption that the alternator 20 is driven at the start (or with a slight time lag), and therefore, the no-load state is defined as the drive state of the alternator 20.

  The idle speed correction system starts at the same time as the engine starts or after a short period of time. First, based on the value of the pedal sensor 28, whether or not the accelerator pedal 29 is not depressed (that is, whether the vehicle speed is zero). Is determined (S1). When the accelerator pedal 29 is depressed, the correction is impossible and the system is terminated. Note that the presence or absence of depression of the accelerator pedal 29 (whether or not the vehicle speed is zero) can be replaced by the opening of the throttle valve.

  If the accelerator pedal 29 is not depressed, it is determined whether or not a load element such as a headlight is OFF (S2). If the load element is ON, the system ends. If the load element is OFF, it is determined whether or not the air conditioner switch 15 is ON (S3). If the air conditioner switch 15 is OFF, the process proceeds directly to rotation speed / load detection (S8). However, if the air conditioner switch 15 is turned on while the correction value for the idle rotation speed is being calculated based on the detected rotation speed / load value, the system is terminated at that point and restarted.

  When the air conditioner switch 15 is ON, in the present control example, the temperature sensor 24 detects the temperature of the evaporator 9 (S4), and then it is determined whether or not the compressor 7 is being driven (S5). When the compressor 7 is being driven, the time required for correcting the idling speed is calculated (S6), and then the compressor 7 is stopped and the influence of the load on the compressor 7 is completely eliminated. The number and the load are detected (S8), and then an appropriate idle speed is calculated again from the relationship between the detected speed and the load, and a correction value for the idle speed is set (S10).

  If the compressor 7 is OFF even though the air conditioner switch 15 is ON, it calculates how much time has elapsed from the temperature of the evaporator 9 before the drive of the compressor 7 is restarted, and the drive restart time If it is shorter than the time required for correcting the idle speed, the drive restart stop time of the compressor 7 is set (S9), and the process proceeds to S8. If there is a sufficient margin until the compressor 7 is driven again, the process may go directly to S8. Instead of detecting the temperature of the evaporator 9, it is also possible to detect the pressure of the refrigerant with a pressure sensor and control it with the pressure of the refrigerant. It is also possible to control by both the refrigerant pressure and the evaporator temperature.

  When the correction value for the idle speed is set, the driving of the compressor 7 that has been forcibly stopped is resumed. This terminates the system. By repeating this system each time the internal combustion engine is started, it is possible to always obtain an appropriate idle ring speed even in a high temperature environment. As a result, fuel consumption can be improved. And since the air conditioner itself does not stop and the blower fan 11 is driven, it does not cause the passenger to misunderstand that the air conditioner is malfunctioning or to feel uncomfortable. Although the blower fan 11 is an electric type, its power is very small, so that the engine load is not changed via the alternator 20. Therefore, the blower fan 11 of the air conditioner does not become a load element.

  When the air conditioner is on and the air volume is higher than the minimum, it is possible to reduce the air volume in accordance with the stop of the compressor 7 drive. As a mode of lowering, it is possible to lower one rank at a time, and it is also possible to lower to the lowest strength. In the case of an air conditioner in which the air volume can be adjusted steplessly, the air volume may be reduced at a preset ratio with respect to the set air volume, for example, 50% cut.

  The present invention is actually applicable to a vehicle equipped with an air conditioner. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Engine room 2 Internal combustion engine 5 Radiator 6 Air-conditioner condenser 7 Air-conditioner compressor 9 Air-conditioner evaporator 11 Air-conditioner blower fan 12 Car interior 15 Air-conditioner switch 19 Auxiliary drive belt 23 ECU as control device
24 Refrigerant pressure sensor 25 Rotation sensor 26 Load sensor 28 Pedal sensor

Claims (1)

An internal combustion engine that detects the engine speed in an unloaded state and corrects the idle speed, and an air conditioner that includes a compressor that operates when the refrigerant pressure or the evaporator temperature falls below a predetermined value are mounted, The compressor of the air conditioner is configured to be driven by the internal combustion engine,
When the air conditioner is ON after the start of the internal combustion engine and the air conditioner is ON, even if the refrigerant pressure or the evaporator temperature of the air conditioner falls below a predetermined value, the air is maintained and the compressor is not driven. The idle speed is corrected by setting the load operation state.
Air-conditioned vehicle.

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