Vehicle control device

Abstract

To favorably prevent both deterioration of output or fuel economy of an internal combustion engine including a supercharger and freezing of condensate water in an intercooler.SOLUTION: A vehicle control device comprises: an internal combustion engine; a supercharger which compresses intake air of the internal combustion engine; an intercooler which cools the air compressed with the supercharger; and a grille shutter which changes an air amount supplied to a heat exchanger cooling the intercooler or a coolant thereof. The vehicle control device minimizes an opening of the grille shutter when an accelerator opening of a vehicle is less than a predetermined opening and the vehicle is under an environment causing condensate water generated in the intercooler or the heat exchanger to freeze.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a control device for a vehicle that includes an internal combustion engine, a supercharger that compresses intake air of the internal combustion engine, and an intercooler that cools the air compressed by the supercharger. [Background technology]

[0002] Conventionally, as a cooling device for cooling compressed air compressed by a compressor of a turbocharger, there is known one including an air-cooled intercooler through which the compressed air passes, a grill shutter for blocking airflow to the intercooler, a temperature sensor for detecting the ambient temperature of the intercooler, a pressure sensor for detecting the pressure value of the compressed air, and a control unit for controlling the opening and closing of the grill shutter (see, for example, Patent Document 1). The control unit of this cooling device controls the grill shutter to close when the detected value of the temperature sensor is below zero and the detected value of the pressure sensor is less than a predetermined threshold value, and controls the grill shutter to open in other cases. The threshold value compared with the detected value of the pressure sensor is determined as a pressure at which condensed water generated in the intercooler is kept in a state not to freeze even when the ambient temperature is below zero. As a result, when there is a risk of the condensed water generated in the intercooler freezing, it is possible to prevent the condensed water from freezing by blocking the airflow to the intercooler with the grill shutter. When there is no risk of the condensed water generated in the intercooler freezing, the grill shutter can be opened to ensure cooling of the compressed air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-069916 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the grill shutter is closed uniformly when there is a risk of condensation water forming in the intercooler freezing, the air compressed by the turbocharger will not be cooled even though it should be, and there is a risk that the output and fuel efficiency of the internal combustion engine will deteriorate due to a reduction in the amount of oxygen.

[0005] Therefore, a main object of the present disclosure is to effectively suppress both the deterioration of output and fuel efficiency of an internal combustion engine including a turbocharger, and the freezing of condensed water in an intercooler. [Means for solving the problem]

[0006] The vehicle control device disclosed herein is a vehicle control device that includes an internal combustion engine, a turbocharger that compresses the intake air of the internal combustion engine, an intercooler that cools the air compressed by the turbocharger, and a grill shutter that changes the amount of air supplied to the intercooler or a heat exchanger that cools the refrigerant of the intercooler, and minimizes the opening of the grill shutter when the accelerator opening of the vehicle is less than a predetermined opening and the vehicle is in an environment that causes condensed water generated in the intercooler or the heat exchanger to freeze.

[0007] The vehicle control device disclosed herein controls a grill shutter that changes the amount of air supplied to an intercooler that cools air compressed by a turbocharger or a heat exchanger that cools the refrigerant of the intercooler. The control device minimizes the opening of the grill shutter when the accelerator opening is less than a predetermined opening and the vehicle is in an environment that freezes condensed water generated in the intercooler or the heat exchanger. As a result, when the accelerator opening is equal to or greater than the predetermined opening, the grill shutter can be opened to supply air to the intercooler or the heat exchanger regardless of the state of the surrounding environment of the vehicle. Therefore, it is possible to suppress a deterioration in the output and fuel efficiency of the internal combustion engine due to the air not being cooled when the accelerator opening is large and the air compressed by the turbocharger should be cooled. Furthermore, when the accelerator opening is not large and the vehicle is in an environment that freezes condensed water generated in the intercooler or the like, the opening of the grill shutter can be minimized to cut off the supply of air (cold air) to the intercooler or the heat exchanger or to reduce the amount of air supplied. As a result, the vehicle control device disclosed herein makes it possible to effectively suppress both a deterioration in output and fuel efficiency of an internal combustion engine including a turbocharger, and freezing of condensed water in an intercooler, etc.

[0008] The control device may maximize the opening degree of the grill shutter when the accelerator opening degree is equal to or greater than the predetermined opening degree, thereby making it possible to satisfactorily secure the output required by the driver when the driver of the vehicle deeply depresses the accelerator pedal.

[0009] Furthermore, the control device may change the opening degree of the grill shutter in accordance with the temperature of the air compressed by the turbocharger when the accelerator opening degree of the vehicle is less than a predetermined opening degree and the vehicle is not in an environment that would cause condensed water generated in the intercooler or the heat exchanger to freeze. This makes it possible to properly maintain the temperature of the air compressed by the turbocharger and to maintain good output and fuel efficiency of the internal combustion engine. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram showing a vehicle including a control device according to the present disclosure. [Diagram 2] 4 is a flowchart showing a grill shutter control routine executed by the control device of the present disclosure. [Diagram 3] 1 is a graph showing the relationship between the opening degree of the grill shutter, the amount of air passing through the grill shutter, the effect of reducing running load resistance, and the effect of improving aerodynamic characteristics. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, an embodiment of the present disclosure will be described with reference to the drawings.

[0012] FIG. 1 is a schematic diagram illustrating a vehicle 1 equipped with an engine 10 controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 100 as a vehicle control device of the present disclosure. In this embodiment, the vehicle 1 includes only the engine 10 as a drive source that generates power for traveling. However, the vehicle 1 may be a hybrid vehicle including a motor generator (electric motor) in addition to the engine 10. The hybrid vehicle may include a first motor generator that mainly operates as a generator, a second motor generator that can output driving torque for traveling and regenerative braking torque, and a power distribution mechanism, or may be a hybrid vehicle including one motor generator, at least one clutch, and a transmission mechanism, or may be a series type hybrid vehicle.

[0013] The engine 10 of the vehicle 1 is an internal combustion engine that converts the reciprocating motion of a piston (not shown) that accompanies the combustion of a mixture of a hydrocarbon fuel or the like and air in a plurality of combustion chambers 11 into the rotational motion of a crankshaft (output shaft). As shown in FIG. 1, the engine 10 includes, in addition to the plurality of combustion chambers 11, an air cleaner 12, an intake pipe 13, an electronically controlled throttle valve 14 built into the intake pipe 13, an intake manifold 15 connected to the intake pipe 13 and the plurality of combustion chambers 11, a plurality of fuel injection valves 16, a plurality of spark plugs 17, an exhaust manifold 18 connected to the plurality of combustion chambers 11, an exhaust pipe 19 that forms an exhaust passage together with the exhaust manifold 18, a plurality of intake valves (not shown) that open and close the corresponding intake ports, and a plurality of exhaust valves (not shown) that open and close the corresponding exhaust ports. The fuel injection valves 16 may be of a type that directly injects fuel into the combustion chambers 11 as shown in the figure, or may be of a type that injects fuel into the intake ports. Also, both a port injection valve and an in-cylinder injection valve may be provided in the engine 10. Furthermore, an exhaust gas purification device including an exhaust gas purification catalyst (three-way catalyst) and a particulate filter that collects particulate matter (fine particles) in the exhaust gas are connected to the exhaust pipe 19 (both are not shown).

[0014] In addition, the engine 10 includes a turbocharger 20 that compresses intake air by utilizing the energy of exhaust gas, and an intercooler 25 that cools the air compressed by the turbocharger 20. As shown in FIG. 1, the turbocharger 20 is a turbocharger that includes a turbine wheel 21, a compressor wheel 22, a turbine shaft 23 that integrally connects the turbine wheel 21 and the compressor wheel 22, a wastegate valve 24, and a blow-off valve (not shown). The turbine wheel 21 is rotatably disposed in a turbine housing formed in the exhaust pipe 19 so as to be located upstream of the exhaust gas purification device. The compressor wheel 22 is rotatably disposed in a compressor housing formed in the intake pipe 13 so as to be located between the air cleaner 12 and the intercooler 25. The wastegate valve 24 is a flow control valve, and is installed in a bypass pipe 19b connected to the exhaust pipe 19 so as to bypass the turbine wheel 21 (turbine housing) as shown in FIG. 1. The blow-off valve (not shown) is installed in a bypass pipe (not shown) that is connected to the intake pipe 13 so as to bypass the compressor wheel 22 (compressor housing). The intercooler 25 is an air-cooled heat exchanger incorporated in the intake pipe 13 so as to be located between the compressor housing and the throttle valve 14, and includes an air passage through which the compressed air compressed by the compressor wheel 22 of the turbocharger 20 passes, a plurality of inner fins and outer fins (heat dissipation fins), etc.

[0015] The engine ECU 100 that controls the engine 10 includes a microcomputer having a CPU, ROM, RAM, input / output interface, etc., not shown, various drive circuits, various logic ICs, etc. The engine ECU 100 also acquires detection values ​​of an accelerator pedal position sensor 90 shown in FIG. 1, a crank angle sensor, an air flow meter, an intake pressure sensor, a boost pressure sensor, an intake temperature sensor 91 shown in FIG. 1, an air-fuel ratio sensor, an exhaust gas temperature sensor, a water temperature sensor, an atmospheric pressure sensor, etc., via an input port not shown. The accelerator pedal position sensor 90 detects the amount of depression of an accelerator pedal (not shown) by a driver of the vehicle 1 (hereinafter referred to as "accelerator opening Acc"). The intake temperature sensor 91 detects an intake temperature Ti, which is the temperature of air (intake air) flowing into the intake manifold 15. The engine ECU 100 calculates the rotation speed Ne of the engine 10 (crankshaft) based on the crank position from the crank angle sensor, and calculates a load factor based on the intake air amount from the air flow meter and the rotation speed Ne of the engine 10. The engine ECU 100 controls the throttle valve 14, the fuel injection valves 16, the spark plugs 17, etc., based on the rotation speed Ne, the load factor, etc. Furthermore, the engine ECU 100 controls the wastegate valve 24 of the turbocharger 20, the blow-off valve, etc.

[0016] The vehicle 1 also includes a grill shutter 30 that opens and closes a front grill FG formed at the front of the vehicle body. As shown in FIG. 1, the grill shutter 30 includes a plurality of (for example, two in this embodiment) upper shielding plates (upper fins) 31 and lower shielding plates (lower fins) 32, and a drive device 33 controlled by the engine ECU 100 described above. The upper shielding plates 31 are arranged side by side in the vehicle width direction so as to open and close the upper part of the front grill FG, and the lower shielding plates 32 are arranged side by side in the vehicle width direction below the upper shielding plates 31 so as to open and close the lower part of the front grill FG. The upper shielding plates 31 and the lower shielding plates 32 are each formed, for example, from resin in a rectangular plate shape, and have shaft portions that protrude in the vehicle width direction from both ends in the vehicle width direction. Each shaft portion is rotatably supported by a frame fixed to the vehicle body, thereby allowing each of the upper shielding plate 31 and the lower shielding plate 32 to rotate around a rotation axis (see dashed line in Figure 1) extending in the vehicle width direction.

[0017] The drive device 33 of the grill shutter 30 includes an electric motor, a link mechanism, etc., and rotates the upper shielding plates 31 synchronously around a rotation shaft, and rotates the lower shielding plates 32 synchronously around a rotation shaft. When the drive device 33 is controlled so that all of the upper shielding plates 31 and the lower shielding plates 32 are substantially horizontal (extending in the vehicle front-rear direction), the grill shutter 30 is in a fully open state (maximum opening) that opens the front grill FG, and allows air to flow into the inside of the vehicle body through the front grill FG. On the other hand, when the drive device 33 is controlled so that all of the upper shielding plates 31 and the lower shielding plates 32 extend in the vertical direction, the grill shutter 30 is in a fully closed state (minimum opening) that closes the front grill FG, and the flow of air into the inside of the vehicle body through the front grill FG is blocked. The drive device 33 can also set the opening degree of the upper shielding plate 31 and the lower shielding plate 32 to an intermediate opening degree between the fully open state and the fully closed state. Furthermore, the drive device 33 includes an opening degree sensor 34 that detects the opening degree of the grill shutter 30 (upper shielding plate 31 and lower shielding plate 32). In this embodiment, the opening degree sensor 34 detects the opening degree of the grill shutter 30 according to the movement amount (rotation amount) of a predetermined link of a link mechanism that rotates the upper shielding plate 31 and the lower shielding plate 32, and transmits a signal indicating the detection value to the engine ECU 100.

[0018] In addition, a radiator (not shown) for cooling the cooling water of the engine 10 and the intercooler 25 for cooling the air compressed by the turbocharger 20 are arranged behind the grill shutter 30 inside the vehicle body. With this arrangement, by fully opening the grill shutter 30, it is possible to send a large amount of air to the radiator and the intercooler 25, and promote the cooling of the cooling water and the air compressed by the turbocharger 20. In addition, by setting the opening degree of the upper shielding plate 31 and the lower shielding plate 32 to an intermediate opening degree between the fully open state and the fully closed state, it is possible to satisfactorily suppress deterioration of the aerodynamic characteristics, etc. of the vehicle 1 while ensuring the cooling performance of the cooling water and the intake air. Furthermore, by fully closing the grill shutter 30, it is possible to suppress overcooling of the cooling water and the intake air, and to better ensure the aerodynamic characteristics, etc., thereby improving the fuel efficiency of the vehicle 1. In addition, an ambient temperature sensor 92 is installed between the grill shutter 30 inside the vehicle body and the intercooler 25, etc. The ambient temperature sensor 92 detects an ambient temperature Ta, which is the temperature of air that has flowed into the vehicle body through the grill shutter 30 in the open state, and transmits a signal indicating the detected value to the engine ECU 100.

[0019] Next, a control procedure for the grill shutter 30 in the vehicle 1 will be described with reference to Figures 2 and 3. Figure 2 is a flowchart illustrating a grill shutter control routine that is repeatedly executed by the engine ECU 100 at predetermined time intervals (vehicle time intervals) while the engine 10 in the vehicle 1 is operating.

[0020] 2, the engine ECU 100 acquires information necessary for controlling the grill shutter 30, such as the accelerator opening Acc detected by the accelerator pedal position sensor 90, the intake air temperature Ti detected by the intake air temperature sensor 91, and the ambient temperature Ta detected by the ambient temperature sensor 92 (step S100). Next, the engine ECU 100 determines whether the accelerator opening Acc acquired in step S100 is less than a predetermined threshold (predetermined opening) Aref (step S110). In this embodiment, the threshold Aref used in step S110 is 100% or a value within a range of, for example, 80-99%. If it is determined that the accelerator opening Acc is equal to or greater than the threshold value Aref (step S110: NO), the engine ECU 100 controls the drive device 33 so that all of the upper shielding plates 31 and the lower shielding plates 32 extend horizontally and the opening degree of the grill shutter 30 is maximized (fully open state) (step S115), and then temporarily terminates the routine of FIG. 2.

[0021] Also, when it is determined that the accelerator opening Acc is less than the threshold value Aref (step S110: YES), the engine ECU 100 determines whether the ambient temperature Ta acquired in step S100 is greater than the freezing temperature Tf (step S110). The freezing temperature Tf as the threshold value used in step S110 is the upper limit of the ambient temperature when the condensed water generated inside the intercooler 25, i.e., in the air passage, freezes, and is a constant value set within the range of, for example, 0°C to -10°C. However, the freezing temperature Tf may be a variable value set according to the ambient air pressure, etc. When it is determined that the ambient temperature Ta is equal to or less than the freezing temperature Tf (step S120: NO), the engine ECU 100 controls the drive device 33 so that all the upper shielding plates 31 and the lower shielding plates 32 extend in the vertical direction and the opening degree of the grill shutter 30 is the minimum opening degree (fully closed state) (step S125), and temporarily ends the routine of FIG. 2.

[0022] Furthermore, when it is determined that the ambient temperature Ta is higher than the freezing temperature Tf (step S120: YES), the engine ECU 100 determines whether the intake air temperature Ti acquired in step S100 is equal to or higher than a temperature obtained by subtracting a predetermined temperature ΔT from a predetermined reference temperature Tref (step S130). The reference temperature Tref that defines the threshold value used in step S130 is an ideal intake air temperature (for example, a temperature within the range of 35°C to 55°C) that can ensure good charging efficiency, knocking characteristics, fuel vaporization characteristics, exhaust characteristics, etc. of the engine 10, and the predetermined temperature ΔT is a temperature of about 5°C, for example. When it is determined that the intake air temperature Ti is lower than the temperature obtained by subtracting the predetermined temperature ΔT from the reference temperature Tref (step S130: NO), the engine ECU 100 controls the drive device 33 so that the opening degree of the grill shutter 30 detected by the opening degree sensor 34 becomes a predetermined small opening degree O1 shown in FIG. 3 (step S135), and once terminates the routine of FIG. 2.

[0023] Also, when it is determined that the intake air temperature Ti is equal to or higher than the temperature obtained by subtracting the predetermined temperature ΔT from the reference temperature Tref (step S130: YES), the engine ECU 100 determines whether the intake air temperature Ti acquired in step S100 is equal to or lower than the reference temperature Tref (step S140). When it is determined that the intake air temperature Ti is higher than the reference temperature Tref (step S140: NO), the engine ECU 100 controls the drive device 33 so that the opening degree of the grill shutter 30 detected by the opening degree sensor 34 becomes a predetermined medium opening degree O2 (O1 < O2 < maximum opening degree) shown in FIG. 3 (step S145), and once terminates the routine of FIG. 2. On the other hand, when it is determined that the intake air temperature Ti is equal to or lower than the reference temperature Tref (step S140: YES), the engine ECU 100 holds the opening degree of the grill shutter 30 at the opening degree set at the time of the previous execution of the routine of FIG. 2 (step S150), and once terminates the routine of FIG. 2.

[0024] As described above, the engine ECU 100 as the vehicle control device of the present disclosure controls the grill shutter 30 to change the amount of air supplied to the intercooler 25 that cools the air compressed by the compressor wheel 22 of the turbocharger 20. When the accelerator opening Acc is equal to or greater than the threshold (predetermined opening) Aref (step S110: NO), the engine ECU 100 maximizes the opening of the grill shutter 30 regardless of the ambient temperature Ta (step S115). When the accelerator opening Acc is less than the threshold Aref and the ambient temperature Ta is equal to or less than the freezing temperature Tf, and the vehicle 1 is in an environment that causes condensed water generated inside the intercooler 25, i.e., in the air passage, to freeze (step S110: YES, step S120: NO), the engine ECU 100 minimizes the opening of the grill shutter 30 (step S125).

[0025] As a result, when the driver of the vehicle 1 depresses the accelerator pedal deeply and the accelerator opening Acc becomes equal to or greater than the threshold value Aref, the grill shutter 30 can be opened to supply a sufficient amount of air to the intercooler 25 regardless of the state of the environment around the vehicle 1. Therefore, even though the accelerator opening Acc is large and the air compressed by the turbocharger 20 should be cooled to increase the amount of oxygen, it is possible to suppress the deterioration of the output and fuel efficiency of the engine 10 due to the air not being cooled, and the output required by the driver can be satisfactorily secured. Also, when the accelerator opening Acc is not so large and the vehicle 1 is in an environment that causes condensed water generated in the air passage of the intercooler 25 to freeze, the opening of the grill shutter 30 can be minimized to cut off the supply of air (cool air) to the intercooler 25. As a result, in the vehicle 1, it is possible to satisfactorily suppress both the deterioration of the output and fuel efficiency of the engine 10 including the turbocharger 20 and the freezing of the condensed water in the intercooler 25. Furthermore, by minimizing the opening degree of the grill shutter 30, the running load resistance and aerodynamic characteristics of the vehicle 1 can be effectively reduced or improved, as shown in FIG.

[0026] Furthermore, when the accelerator opening Acc is less than the threshold Aref, the ambient temperature Ta is greater than the freezing temperature Tf, and the vehicle 1 is not in an environment that would freeze condensed water generated in the air passage of the intercooler 25 (steps S110: YES, step S120: YES), the engine ECU 100 changes the opening of the grill shutter 30 according to the intake air temperature Ti, which is the temperature of the air compressed by the turbocharger 20 (steps S130, S135, S140, S145). This makes it possible to properly maintain the temperature of the air compressed by the turbocharger 20, to maintain good output and fuel economy of the engine 10, and to reduce or improve the running load resistance and aerodynamic characteristics of the vehicle 1 by adjusting the opening of the grill shutter 30 (see FIG. 3).

[0027] The intercooler 25 of the engine 10 is not limited to an air-cooled heat exchanger, and may be a liquid-cooled heat exchanger that cools the air compressed by the turbocharger 20 using a liquid refrigerant. In this case, an air-cooled heat exchanger (radiator) that cools the liquid refrigerant of the intercooler 25 by heat exchange with the air may be disposed behind the grill shutter 30. The configuration of the grill shutter 30 is not limited to the above-mentioned configuration as long as it can introduce or block air to the intercooler 25 or the air-cooled heat exchanger. Furthermore, the grill shutter 30 (drive device 33) may be configured to slightly open at least one of the upper shielding plate 31 and the lower shielding plate 32 when the opening degree of the grill shutter 30 is minimum to allow a small amount of air to flow (see the two-dot chain line in FIG. 3). In addition, step S120 in FIG. 2 may make a positive determination when the ambient temperature Ta is higher than the freezing temperature Tf and the pressure of the compressed air (boost pressure) detected by a boost pressure sensor (not shown) is equal to or higher than a pressure that can be maintained without freezing condensed water in the intercooler 25 or the like.

[0028] The present disclosure is not limited to the above embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above embodiment is merely a specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0029] The present disclosure is applicable to the vehicle manufacturing industry and the like. [Explanation of symbols]

[0030] 1 vehicle, 10 engine, 11 combustion chamber, 12 air cleaner, 13 intake pipe, 14 throttle valve, 15 intake manifold, 16 fuel injection valve, 17 spark plug, 18 exhaust manifold, 19 exhaust pipe, 19b bypass pipe, 20 turbocharger, 21 turbine wheel, 22 compressor wheel, 23 turbine shaft, 24 wastegate valve, 25 intercooler, 30 grill shutter, 31 upper shielding plate, 32 lower shielding plate, 33 drive mechanism, 34 opening sensor, 90 accelerator pedal position sensor, 91 intake temperature sensor, 92 ambient temperature sensor, 100 engine electronic control unit (engine ECU).

Claims

[Claim 1] A control device for a vehicle including an internal combustion engine, a supercharger that compresses intake air of the internal combustion engine, an intercooler that cools the air compressed by the supercharger, and a grill shutter that changes an amount of air supplied to the intercooler or a heat exchanger that cools a refrigerant of the intercooler, A vehicle control device that minimizes the opening degree of the grill shutter when the accelerator opening of the vehicle is less than a predetermined opening degree and the vehicle is in an environment that would freeze condensed water generated in the intercooler or the heat exchanger, changes the opening degree of the grill shutter in accordance with the temperature of air compressed by the turbocharger when the accelerator opening of the vehicle is less than the predetermined opening degree and the vehicle is not in an environment that would freeze condensed water generated in the intercooler or the heat exchanger, and maximizes the opening degree of the grill shutter when the accelerator opening is equal to or greater than the predetermined opening degree.

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