hybrid vehicle

Abstract

Hybrid vehicle (10), with a machine (110); a motor generator (MG1, MG2), wherein the engine (110) and the motor generator (MG1, MG2) are accommodated in an engine compartment (100) of the hybrid vehicle (10); an accumulator (200) configured to be rechargeable by the motor generator (MG1, MG2) driven by the engine (110) when a remaining capacity of the accumulator (200) decreases; a shutter (120) provided at an air passage (600), wherein the shutter (120) is configured to admit air from outside the hybrid vehicle (10) into the engine compartment (100), and wherein the shutter (120) is configured to be openable and closeable; an air conditioning system (300) comprising an electrically operated compressor (310), wherein the electrically operated compressor (310) is arranged to be driven by receiving electrical energy from the accumulator (200); and an electronic control unit (400) configured to limit a power of the electrically operated compressor (310) when the shutter (120) has a closing error in which the shutter (120) cannot be brought into an open state.

Description

Technical field

[0001] The present invention relates to a hybrid vehicle and, more particularly, to a control of a hybrid vehicle when a grill shutter is inoperable. State of the art

[0002] In recent years, hybrid vehicles, which are equipped with an engine and a traction motor as power sources, have been used in practice.

[0003] In a hybrid vehicle, heat is generated by an engine, traction motor, and the like. Heat is dissipated from the engine, traction motor, and the like by cooling a radiator.

[0004] The radiator is located, for example, in the interior of the vehicle body (inside an engine compartment). The radiator is cooled by drawing air from outside the vehicle (outside air) into the engine compartment. The intake of outside air is achieved, for example, through a grille closure provided on an air vent for drawing outside air into the engine compartment. The grille closure is designed to be openable and closed.

[0005] JP 2011 - 105 219 A proposes to detect a fault or to indicate a fault when a grill shutter is not operable.

[0006] EP 2 184 568 A2 and DE 10 2013 205 229 A1 each show conventional vehicles powered solely by an engine and equipped with an air conditioning system.

[0007] DE 101 30 841 A1 shows a compressor for an air conditioning system. Citation listPatent literature PTL1: JP 2011 - 105 219 A PTL2: WO 2012 / 029 521 A1 PTL 3: EP 2 184 568 A2 PTL 4: DE 10 2013 205 229 A1 PTL 5: DE 101 30 841 A1 SUMMARY OF THE INVENTIONTechnical problem

[0008] In a hybrid vehicle, the electrical energy of a battery is used not only to drive a traction motor but also to drive an electrically driven compressor of an air conditioning device. Furthermore, a hybrid vehicle can perform control such that when the remaining capacity (SOC: State of Charge) of a battery decreases, an engine is started, a power generator is driven by the engine, and the battery is thereby charged.

[0009] In such a hybrid vehicle, the following problem may occur when an air conditioner is used, that is, an electrically driven compressor is driven in a case where a grill shutter is stuck in a closed state and cannot be moved to an open state (that is, the grill shutter has a closure failure). Namely, the SOC of the battery decreases due to the use of the air conditioner, and the engine is started to charge the battery, generating heat. Because the grill shutter cannot be moved to an open state even though the engine generates heat, the temperature inside the engine compartment increases. If the temperature inside the engine compartment increases, the output of the engine, the traction motor, and the like may be limited, for example, by activating a protective function.

[0010] The object of the present invention is to enable an increase in temperature within an engine compartment during operation of an air conditioner of a hybrid vehicle to be suppressed even in a state where the grille shutter has a closing failure. Solution to the task

[0011] The object is achieved by a hybrid vehicle having the features of claim 1. Advantageous developments of the present invention are the subject of the dependent claims.

[0012] In the hybrid vehicle according to the invention, an increase in temperature inside the engine compartment is suppressed by allowing outside air into the engine compartment when the shutter can be set to an open state. On the other hand, when the shutter has the closure failure, the output of the electrically driven compressor is limited. When the output of the electrically driven compressor is limited, the power consumption of the electrically driven compressor decreases, and the decrease in the SOC of the battery is suppressed. When the decrease in the SOC of the battery is suppressed, the chances of the power generator being driven by the engine to charge the battery decrease. As a result, the probability of the temperature inside the engine compartment increasing due to heat generation by the engine also decreases.

[0013] The pressure of the air conditioning refrigerant may fluctuate due to the closure failure of the shutter. According to a preferred configuration, control is performed upon the closure failure of the shutter based on the pressure of the air conditioning refrigerant, that is, limiting the capacity of the electrically driven compressor. Further, according to the preferred configuration, the capacity of the electrically driven compressor is gradually limited based on two limit values, that is, the first predetermined value and the second predetermined value.

[0014] Preferably, the control unit limits a speed of the electrically driven compressor when the shutter has the closing error.

[0015] If the speed of the electrically driven compressor is limited, the energy consumption of the electrically driven compressor is also reduced. Advantageous effects of the invention

[0016] According to the present invention, it is possible to limit an increase in temperature inside an engine compartment when operating an air conditioner in a hybrid vehicle even in a case where the grill shutter has a closing failure. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a schematic configuration of a hybrid vehicle 10 according to an embodiment. Fig. 2 is a flowchart showing an operation performed upon the grill shutter closing failure. DESCRIPTION OF THE EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that identical or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0018] Fig. 1 is a view showing a schematic configuration of a hybrid vehicle 10 according to an embodiment.

[0019] Referring to Fig. 1, a hybrid vehicle 10 includes an engine compartment 100, an HV (hybrid vehicle) battery 200 (hereinafter also called HV battery or battery), an air conditioning unit 300, an ECU 400 (hereinafter also called electronic control unit or control unit), drive wheels 500, and an air passage 600.

[0020] The engine compartment 100 is a body interior of a hybrid vehicle 10. The engine compartment 100 accommodates an engine 110 and an engine cooler 111.

[0021] The engine 110 is an internal combustion engine that generates driving force. The engine 110 generates heat when it generates driving force. The engine 110 is cooled with cooling water. This cooling water circulates between the engine 110 and the engine radiator 111.

[0022] The machine cooler 111 is a heat exchanger that performs heat exchange between the cooling water for the machine 110 and an outside air and cools the cooling water.

[0023] The engine compartment 100 further accommodates an electrically powered drive unit 150. The electrically powered drive unit 150 includes a power control unit (PCU) 160, motor generators MG1 and MG2, and a drive force split device 170.

[0024] Motor generators MG1 and MG2 receive electrical power from PCU 160 and generate driving forces. Motor generators MG1 and MG2 can also generate electrical power using the driving force of engine 110. Furthermore, motor generators MG1 and MG2 can also generate electrical power using regenerative energy when hybrid vehicle 10 performs regenerative braking.

[0025] The PCU 160 converts electrical energy from an HV battery 200 (described later) into electrical energy for driving the motor generators MG1 and MG2. The PCU 160 can also convert electrical energy from the motor generators MG1 and MG2 into charging energy for the HV battery 200.

[0026] The driving force splitting device 170 splits a driving force from the engine 110 and transmits the split driving force to each of the motor generators MG1 and MG2.

[0027] The PCU 160 includes an inverter 161 and an inverter 162. The inverter 161 is used for converting electrical energy between the motor generator MG1 and the HV battery 200. The inverter 162 is used for converting electrical energy between the motor generator MG2 and the HV battery 200.

[0028] The electric drive unit 150, which includes the PCU 160 and the motor generators MG1 and MG2, generates heat. Therefore, the electric drive unit 150 is cooled with cooling water. This cooling water circulates between the electric drive unit 150 and an HV (hybrid vehicle) radiator 151.

[0029] The HV cooler 151 is a heat exchanger that performs heat exchange between the cooling water for the electrically operated drive unit 150 and the outside air and cools the cooling water.

[0030] The engine compartment 100 is further equipped with a condenser 340. The condenser 340 is a heat exchanger that performs heat exchange between a coolant for an air conditioning unit 300 and the air outside the hybrid vehicle 10 and cools the coolant.

[0031] Further, the engine compartment 100 includes a grill shutter 120, an actuator 121, and a sensor 122. The grill shutter 120 is provided at an air passage 600 (described later).

[0032] The grille shutter 120 is configured to be switchable between an open state and a closed state. For example, when the grille shutter 120 is set to an open state, the air outside the hybrid vehicle 10 (outside air) can be taken into the engine compartment 100. Further, when the grille shutter 120 is set to a closed state, for example, aerodynamic force during driving can be improved (for example, air resistance can be reduced).

[0033] The actuator 121 opens and closes the grill shutter 120. The sensor 122 determines whether the grill shutter 120 is in an open state or a closed state.

[0034] The HV battery 200 is an energy storage device configured to be chargeable and dischargeable. The HV battery 200 is configured, for example, to include a secondary battery, such as a lithium-ion battery, a nickel-hydride battery, a lead-acid storage battery, or the like, or an energy storage element, such as an electric double-layer capacitor.

[0035] In the hybrid vehicle 10, the HV battery 200 is charged as needed. For example, when the SOC of the HV battery 200 decreases, the engine 110 drives the motor generator MG1, and the motor generator MG1 generates electrical energy. The electrical energy generated by the motor generator MG1 is converted by the PCU 160 into charging energy for the HV battery 200. This charges the HV battery 200 and maintains or increases the SOC of the HV battery 200.

[0036] The air conditioning unit 300 includes a compressor 310, an evaporator 320, an expansion valve 330, a condenser 340, a thermistor 350, an inverter 360, and a pressure sensor 370.

[0037] The air conditioning unit 300 can perform a cooling operation, a heating operation, and the like. The air conditioning unit 300 uses a refrigerant (for example, a refrigerant gas).

[0038] In the cooling operation, for example, the refrigerant flows out into the evaporator 320 through the expansion valve 330. The temperature of the evaporator 320 is reduced by the refrigerant flowing out into the evaporator 320. This demonstrates the cooling function of the evaporator 320. The air conditioning unit 300 performs the cooling operation using the cooling function of the evaporator 320.

[0039] The refrigerant flowing into the evaporator 320 is then compressed by the compressor 310 and transported to the condenser 340. The refrigerant transported to the condenser 340 is cooled by the condenser 340 acting as a heat exchanger. The refrigerant is then discharged back into the evaporator 320 through the expansion valve 330.

[0040] Note that the heating operation is performed by switching the direction of an output of the compressor 310 to a direction opposite to that for the cooling operation. This switching is implemented, for example, by providing the compressor 310 with a four-way valve (not shown).

[0041] In the hybrid vehicle 10, the compressor 310 included in the air conditioning unit 300 is an electrically driven compressor that operates using electrical energy. Specifically, the compressor 310 operates by receiving AC electrical energy from the inverter 360. Typically, the compressor 310 is an electrically driven rotary compressor.

[0042] As the power (rotational speed) of the compressor 310 increases, the cooling function and the heating function (cooling / heating function) of the air conditioning unit 300 improve, while the power consumption of the compressor 310 increases. On the other hand, as the power of the compressor 310 decreases, the cooling / heating function of the air conditioning unit 300 decreases, while the power consumption of the compressor 310 decreases.

[0043] The thermistor 350 is used to detect the temperature of the evaporator 320.

[0044] The inverter 360 converts DC electrical energy from the HV battery 200 into AC electrical energy and supplies the AC electrical energy to the compressor 310. Namely, the electrical energy consumed by the compressor 310 is supplied by the HV battery 200.

[0045] The pressure sensor 370 detects the pressure of the refrigerant flowing through the air conditioning unit 300. The refrigerant pressure is measured, for example, at a location before or after the compressor 310 or before or after the expansion valve 330, where the refrigerant pressure changes quite significantly.

[0046] It is noted that although the condenser 340 of the air conditioning unit 300 in Fig. 1 as being contained in the engine compartment 100, the present invention is not limited to such a configuration. For example, the air conditioning unit 300 itself may be contained in the engine compartment 100.

[0047] The ECU 400 includes a CPU (processor), a memory device, and an input / output buffer, which are not shown. The ECU 400 receives a signal from each sensor or the like, outputs a control signal to each device, and controls the hybrid vehicle 10 and each device. It is noted that such control can be performed not only by software operations but also by operations involving specific hardware (electronic circuits).

[0048] The drive wheels 500 are used to drive the hybrid vehicle 10. The drive wheels 500 are driven by the motor generator MG2.

[0049] The air passage 600 is provided to receive air from outside the hybrid vehicle 10.

[0050] In a hybrid vehicle 10, the grille shutter 120 may be inoperable. Examples of failures include a closing failure, in which the grille shutter 120 is stuck in a closed state and cannot be moved to an open state, and an opening failure, in which the grille shutter 120 is conversely stuck in the open state and cannot be moved to the closed state.

[0051] When the air conditioning unit 300 is operating, that is, the compressor 310 is operating, the following problem may occur in a case where the grill shutter 120 has the closure failure. Namely, when the compressor 310 is operating and the electric power of the HV battery 200 is consumed, the SOC of the HV battery 200 decreases. When the SOC of the HV battery 200 decreases, the engine 110 is started to charge the HV battery 200. However, the engine 110 generates heat when the engine 110 is started. At this time, the temperature of the engine compartment 100 increases because the grill shutter 120 cannot be set to the open state. When the temperature inside the engine compartment 100 increases, the output of the engine 110, the motor generators MG1 and MG2, and the like may be limited, for example, by activating a protective function.

[0052] Accordingly, in the present embodiment, the capacity of the compressor 310 of an air conditioning unit 300 is limited when the grill shutter has the closing failure.

[0053] When the power of the compressor 310 is limited, the SOC of the HV battery 200, which supplies the electrical energy to be consumed by the compressor 310, is prevented from becoming lower. When the SOC of the HV battery 200 is prevented from becoming lower, the opportunities for the motor generator MG1 to be driven by the engine 110 to charge the HV battery 200 are also reduced. As a result, the probability that the temperature inside the engine compartment 100 will increase due to heat generation by the engine 110 also decreases.

[0054] Furthermore, in the embodiment, the capacity of the compressor 310 is limited based on the pressure of the refrigerant flowing through the air conditioning unit 300. Specifically, the capacity of the compressor 310 is reduced (from a rated value) when the pressure of the refrigerant is greater than a first predetermined value. Furthermore, the compressor 310 is stopped when the pressure of the refrigerant is greater than a second predetermined value. The second predetermined value is set to be higher than the first predetermined value.

[0055] When the grille shutter 120 has the closure failure and the cooling of the condenser 340 is not fully performed, the pressure of the refrigerant flowing through the air conditioning unit 300 tends to increase. Therefore, by gradually limiting the capacity of the compressor 310 based on the refrigerant pressure, a decrease in the SOC of the HV battery 200 can be suppressed, and thereby an increase in the temperature inside the engine compartment 100 due to heat generation by the engine 110 can be suppressed.

[0056] The power of the compressor 310 is limited, for example, by limiting the speed of the compressor 310.

[0057] The performance of the compressor 310 can also be limited by operating the compressor 310 intermittently.

[0058] The operation of the hybrid vehicle 10 in the embodiment described above is implemented by the control unit 400, which controls each element of the hybrid vehicle 10.

[0059] According to the hybrid vehicle 10 in accordance with the present embodiment, it is possible to suppress a rise in temperature inside the engine compartment 100 when operating an air conditioning unit 300 even in a case where the grill shutter 120 has the closing failure.

[0060] Fig. Figure 2 is a flowchart showing a process performed upon the closing failure of the grill shutter. The process in this flowchart is performed as a subroutine called from a predetermined main routine. Furthermore, the process in this flowchart is executed by the Fig. 1 shown control unit 400.

[0061] With reference to Fig. 1 and Fig. 2, it is first determined in step S1 whether the grill shutter 120 has the closure error or not. This determination is made based, for example, on a detection result of the sensor 122. If the grill shutter 120 has the closure error (YES in step S1), the process proceeds to step S2. On the other hand, if the grill shutter 120 does not have a closure error (NO in step S1), the flowchart of the Fig. 2 and the process returns to the main routine.

[0062] In step S2, it is determined whether the pressure of the refrigerant flowing through the air conditioning unit 300 (refrigerant pressure) is greater than P1 as the first predetermined value. If the refrigerant pressure is greater than P1 (YES in step S2), the process proceeds to step S3. On the other hand, if the refrigerant pressure is lower than or equal to P1 (NO in step S2), the flowchart of the Fig. 2 and the process returns to the main routine.

[0063] In step S3, the capacity of the air conditioning unit 300 is limited. Specifically, the rotational speed of the compressor 310 is limited. Note that if the rotational speed of the compressor 310 is already limited, the limited rotational speed is maintained. After that, the process proceeds to step S4.

[0064] In step S4, it is determined whether the coolant pressure is greater than P2 than the second predetermined value. P2 is a value greater than P1 used in step S2. If the coolant pressure is greater than P2 (YES in step S4), the process proceeds to step S5. On the other hand, if the coolant pressure is lower than or equal to P2 (NO in step S4), the flowchart of the Fig. 2 and the process returns to the main routine.

[0065] In step S5, the power of the air conditioning unit 300 is stopped. Specifically, the operation of the compressor 310 is stopped. Note that if the operation of the compressor 310 has already stopped, the stopped state is maintained. After the process at step S5 is completed, the flowchart of the Fig. 2 and the process returns to the main routine.

[0066] According to the flow chart of the Fig. 2, when the grill shutter 120 has a closure failure, the output of the air conditioning unit 300 is gradually limited in accordance with the pressure of the coolant flowing through the air conditioning unit 300. When the output of the air conditioning unit 300 is limited, the decrease in the SOC of the HV secondary battery 200 is suppressed. As a result, the cases where the motor generator MG1 is driven by the engine 110 are reduced, and an increase in the temperature inside the engine compartment 100 due to heat generation by the engine 110 is suppressed.

[0067] Finally, the embodiment of the present invention is summarized. Referring to Fig. 1, a hybrid vehicle 10 according to the embodiment includes an engine 110, a motor, and a power generator (motor generators MG1 and MG2). The hybrid vehicle 10 includes: a secondary battery (HV secondary battery 200) charged by the engine 110, which drives the power generator (motor generator MG1) when the remaining capacity (SOC) decreases; an engine compartment 100 that houses the engine 110 and the motor (motor generators MG1 and MG2); a shutter (grill shutter 120) provided at an air passage 600 for taking air from outside the hybrid vehicle 10 into the engine compartment 100, and which can be opened and closed; an air conditioner (air conditioning unit 300) including an electrically driven compressor (compressor 310) driven by receiving electrical energy from the accumulator (HV accumulator 200);and a control unit 400 that limits a power of the electrically operated compressor (compressor 310) when the shutter (grill shutter 120) has a closing error in which the shutter cannot be brought into an open state.;

[0068] Preferably, the air conditioning system (air conditioning unit 300) comprises a coolant. As in Fig. As shown in Figure 2, the control unit 400 reduces the power of the electrically driven compressor (compressor 310) (step S3) when the pressure of the refrigerant is greater than a first predetermined value (P1) (YES in step S2). When the pressure of the refrigerant is greater than a second predetermined value (P2) (YES in step S4), the control unit 400 stops the electrically driven compressor (compressor 310) (step S5). The second predetermined value (P2) is greater than the first predetermined value (P1).

[0069] Preferably, the control unit 400 limits a rotational speed of the electrically driven compressor (compressor 310) when the shutter (grill shutter 120) has the closing error. List of reference symbols

[0070] MG1, MG2: Motor generator; 10: Hybrid vehicle; 100: Engine compartment; 110: Engine; 111: Engine cooler; 120: Grill shutter; 121: Actuator; 122: Sensor; 150: Electrically operated drive unit; 151: HV cooler; 161, 162, 360: Inverter; 170: Drive power split device; 200: HV accumulator; 300: Air conditioning unit; 310: Compressor; 320: Evaporator; 330: Expansion valve; 340: Condenser; 350: Thermistor; 370: Pressure sensor; 400: Control unit; 500: Drive gear; 600: Air passage.

Claims

[1] Hybrid vehicle (10), with a machine (110); a motor generator (MG1, MG2), wherein the engine (110) and the motor generator (MG1, MG2) are accommodated in an engine compartment (100) of the hybrid vehicle (10); an accumulator (200) configured to be rechargeable by the motor generator (MG1, MG2) driven by the engine (110) when a remaining capacity of the accumulator (200) decreases; a shutter (120) provided at an air passage (600), wherein the shutter (120) is configured to admit air from outside the hybrid vehicle (10) into the engine compartment (100), and wherein the shutter (120) is configured to be openable and closeable; an air conditioning system (300) comprising an electrically operated compressor (310), wherein the electrically operated compressor (310) is arranged to be driven by receiving electrical energy from the accumulator (200); and an electronic control unit (400) configured to limit a power of the electrically operated compressor (310) when the shutter (120) has a closing error in which the shutter (120) cannot be brought into an open state. [2] Hybrid vehicle (10) according to claim 1, wherein the air conditioning system (300) further comprises a coolant, the electronic control unit (400) is configured to reduce the power of the electrically operated compressor (310) when a pressure of the coolant is higher than a first predetermined value, the electronic control unit (400) is arranged to stop the electrically operated compressor (310) when the pressure of the refrigerant is higher than a second predetermined value, and wherein the second predetermined value is greater than the first predetermined value. [3] The hybrid vehicle (10) according to claim 1 or 2, wherein the electronic control unit (400) is configured to limit a rotational speed of the electrically driven compressor (310) when the shutter (120) has the closing failure.

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