Vehicle control device, vehicle control method, and program

Abstract

[Problem] To provide a vehicle control device which is able to appropriately control a transmission in the event that a check valve provided to an intake side does not open. [Solution] According to the present invention, a vehicle is provided with a transmission that has a first oil pump driven by rotation of a driving source for driving drive wheels and has a second oil pump which is driven by a motor and which has a check valve provided to the intake side. In the case where a driving current value of the motor becomes lower than a first current value, which denotes the minimum value of the driving current value of the motor at a time when the second oil pump is driven in a normal drive mode, upon driving of the second oil pump, this vehicle control device for controlling the vehicle increases the minimum rotation speed of the driving source than in a case where the driving current value of the motor is not less than the first current value, when executing automatic downshift control for automatically downshifting the transmission gear ratio of the transmission.

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device, a vehicle control method, and a program executable by a computer for controlling a vehicle. Regarding. [Background technology]

[0002] Patent Document 1 discloses that the hydraulic oil supply device includes a mechanical oil pump having a first suction port, an electric oil pump having a second suction port and a lower capacity than the mechanical oil pump, and a strainer having a hydraulic oil suction port, a first discharge port connected to the first suction port, and a second discharge port connected to the second suction port, and that the device is provided with a check valve located between the suction port and the second suction port, which opens when the mechanical oil pump is not driven but the electric oil pump is driven, and closes when the mechanical oil pump is driven but the electric oil pump is not driven. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-165516 Summary of the Invention [Problem to be solved by the invention]

[0004] In the hydraulic oil supply device described in Patent Document 1, if the check valve does not open, the amount of oil supplied from the electric oil pump will decrease, causing a shortage of oil in the transmission mechanism and possibly causing a delay in gear shifting.

[0005] The present invention has been made in consideration of these problems, and aims to provide a vehicle control device and control method that can appropriately control the transmission when the check valve provided on the intake side does not open. [Means for solving the problem]

[0006] A vehicle according to one aspect of the present invention is equipped with a transmission having a first oil pump driven by rotation of a drive source that drives drive wheels, and a second oil pump that has a check valve on its intake side and is driven by a motor. Furthermore, a vehicle control device that controls the vehicle controls the vehicle by determining a first current value that is the minimum value of the drive current of the motor when the second oil pump is driven in a normal driving state. Perform fault determination, When the motor drive current value is lower than the first current value, Turn on the abnormal flag, When executing auto downshift control to automatically downshift the gear ratio of the transmission, The system determines whether the abnormality flag is on or off due to a malfunction judgment performed separately from the auto downshift control, and if the abnormality flag is on, it turns off. The minimum rotation speed of the drive source is increased compared to the case of (1). [Effects of the Invention]

[0009] this According to this aspect, the transmission can be appropriately controlled when the check valve provided on the intake side does not open. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a hydraulic control circuit for a transmission according to this embodiment. [Figure 2] FIG. 2 is a diagram showing an abnormal region of the electric oil pump according to this embodiment. [Figure 3] FIG. 3 is a flowchart relating to the abnormality determination of the check valve. [Figure 4] FIG. 4 is a flowchart relating to the auto-down control. [Figure 5] FIG. 5 is a flowchart relating to the idling stop control. [Figure 6] FIG. 6 is a flowchart relating to the coast stop control. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0012] 1 is a schematic diagram of a vehicle 100. The vehicle 100 includes an engine ENG, a torque converter TC, a forward / reverse switching mechanism SWM, and a variator VA. In the vehicle 100, the transmission TM is a continuously variable belt transmission having the torque converter TC, the forward / reverse switching mechanism SWM, and the variator VA.

[0013] The engine ENG constitutes the drive source of the vehicle 100. The engine ENG is, for example, a gasoline engine. The power of the engine ENG is transmitted to the drive wheels DW via the torque converter TC, the forward / reverse switching mechanism SWM, and the variator VA. In other words, the torque converter TC, the forward / reverse switching mechanism SWM, and the variator VA are provided in a power transmission path connecting the engine ENG and the drive wheels DW.

[0014] The torque converter TC transmits power via a fluid. In the torque converter TC, the lock-up clutch LU is engaged to increase power transmission efficiency.

[0015] The forward / reverse switching mechanism SWM is provided in a power transmission path connecting the engine ENG and the variator VA. The forward / reverse switching mechanism SWM switches the rotation direction of the input rotation to switch between forward and reverse travel of the vehicle 100. The forward / reverse switching mechanism SWM includes a forward clutch FWD / C that is engaged when the forward (D) range is selected, and a reverse brake REV / B that is engaged when the reverse (R) range is selected. When the forward clutch FWD / C and the reverse brake REV / B are released, the transmission TM enters a neutral state, i.e., a power cut-off state.

[0016] The variator VA constitutes a belt continuously variable transmission mechanism having a primary pulley PRI, a secondary pulley SEC, and a belt BLT wound around the primary pulley PRI and the secondary pulley SEC. A primary pulley pressure Ppri, which is a hydraulic pressure for driving the primary pulley PRI, and a secondary pulley pressure Psec, which is a hydraulic pressure for driving the secondary pulley SEC, are supplied to the primary pulley PRI and the secondary pulley SEC, respectively, from a hydraulic control circuit 1, which will be described later.

[0017] The transmission TM further comprises a mechanical oil pump MP, an electric oil pump EP, a motor M, a hydraulic control circuit 1, a check valve 25, and a check valve 26. The mechanical oil pump MP supplies hydraulic oil drawn from an oil pan T to the hydraulic control circuit 1. The mechanical oil pump MP is driven by the power of the engine ENG. The electric oil pump EP is driven by the power of the motor M. The electric oil pump EP, together with the mechanical oil pump MP or independently, supplies hydraulic oil drawn from the oil pan T to the hydraulic control circuit 1. The electric oil pump EP is provided auxiliary to the mechanical oil pump MP. The electric oil pump EP comprises the motor M.

[0018] The hydraulic control circuit 1 is composed of a plurality of flow paths and a plurality of hydraulic control valves, and regulates the pressure of hydraulic oil supplied from the mechanical oil pump MP and the electric oil pump EP, and supplies the hydraulic oil to each part of the transmission TM.

[0019] The operations of the engine ENG and the transmission TM are controlled by a controller 2 serving as a control device. The controller 2 has an engine controller (not shown) and a transmission controller (not shown). Both of these are configured as electronic control units and are made up of a microcomputer equipped with a central processing unit (CPU), various storage devices such as RAM and ROM, an input / output interface, etc. The engine controller and the transmission controller are connected to each other via a CAN standard bus so as to be able to communicate with each other. The controller 2 performs various processes by having the CPU read and execute various programs stored in the ROM, etc. The various programs executed by the controller 2 may be stored in a non-transitory storage medium such as a CD-ROM.

[0020] The controller 2 (engine controller) receives detection signals from an operating condition sensor that detects the operating condition of the engine ENG, performs predetermined calculations based on the operating condition, and sets the fuel injection amount, fuel injection timing, ignition timing, etc. of the engine ENG. The rotation speed, torque, etc. of the engine ENG are controlled based on commands from the controller 2 (engine controller). As operating condition sensors, an accelerator sensor that detects the amount of accelerator pedal operation by the driver (hereinafter referred to as "accelerator opening"), a rotation speed sensor that detects the rotation speed Ve of the engine ENG, a coolant temperature sensor that detects the temperature of the engine coolant, etc. are provided.

[0021] In addition, controller 2 (transmission controller) receives detection signals from various sensors that detect the operating state of transmission TM, and controls the operation of hydraulic control circuit 1 and electric oil pump EP based on these signals. Based on instructions from controller 2, hydraulic control circuit 1 performs hydraulic control of lockup clutch LU, forward clutch FWD / C, reverse brake REV / B, primary pulley PRI, secondary pulley SEC, etc.

[0022] The check valve 25 allows the flow of hydraulic oil from the mechanical oil pump MP toward the hydraulic control circuit 1, and blocks the flow of hydraulic oil from the hydraulic control circuit 1 toward the mechanical oil pump MP. This prevents the line pressure PL from acting on the mechanical oil pump MP when the mechanical oil pump MP is stopped, for example.

[0023] The check valve 26 allows the flow of hydraulic oil from the electric oil pump EP toward the hydraulic control circuit 1, and blocks the flow of hydraulic oil from the hydraulic control circuit 1 toward the electric oil pump EP. This prevents the line pressure PL from acting on the electric oil pump EP when the electric oil pump EP is stopped, causing the electric oil pump EP to rotate in the reverse direction.

[0024] A check valve 27 is provided between the electric oil pump EP and the oil pan T. The check valve 27 prevents hydraulic oil from being returned to the oil pan T from within the electric oil pump EP and from the flow path on the suction side of the electric oil pump EP when the electric oil pump EP is stopped. This prevents air from being mixed into the electric oil pump EP, in other words, prevents the electric oil pump EP from suctioning insufficient hydraulic oil, and suppresses a delay in the rise of hydraulic pressure when the electric oil pump EP is operating.

[0025] Next, the operation modes of the mechanical oil pump MP and the electric oil pump EP will be described.

[0026] The controller 2 switches the operation modes of the mechanical oil pump MP and the electric oil pump EP according to the operating conditions of the vehicle 100. In this embodiment, the operation modes include an MP mode in which only the mechanical oil pump MP is driven by the engine ENG, an EP mode in which only the electric oil pump EP is driven, and a TDP mode in which both the mechanical oil pump MP and the electric oil pump EP are driven.

[0027] The MP mode is selected when the rotation speed Ve of the engine ENG is high. Specifically, the MP mode is selected when the flow rate required by the hydraulic equipment mounted on the vehicle 100 (hereinafter referred to as the "required flow rate") can be met by the discharge flow rate discharged by the mechanical oil pump MP. The discharge flow rate of the mechanical oil pump MP is proportional to the rotation speed Ve of the engine ENG. Therefore, when the rotation speed Ve of the engine ENG is high, the required flow rate can be met by the power of the engine ENG alone, that is, the discharge flow rate based on the mechanical oil pump MP. In the MP mode, the electric oil pump EP is kept stopped.

[0028] The EP mode is selected when the engine ENG is stopped. When an idling stop, coast stop, or the like is being performed, the rotation of the engine ENG is stopped, and therefore the rotation of the mechanical oil pump MP is also stopped. Therefore, when the rotation of the engine ENG is stopped, the controller 2 drives the motor M to drive the electric oil pump EP. This makes it possible to cover the required flow rate with the discharge flow rate based on the electric oil pump EP.

[0029] The TDP mode is selected when the required flow rate cannot be met by the discharge flow rate based solely on the power of the engine ENG, specifically, when the rotation speed Ve of the engine ENG is low. As described above, when only the engine ENG is driven, the discharge flow rate of the mechanical oil pump MP is proportional to the rotation speed Ve of the engine ENG. Therefore, when the rotation speed Ve of the engine ENG is low, the required flow rate cannot be met by the discharge flow rate based solely on the mechanical oil pump MP. Therefore, the controller 2 drives the motor M to drive the electric oil pump EP. This makes it possible to meet the required flow rate, which would be insufficient if the discharge flow rate based solely on the mechanical oil pump MP were to be met, by the discharge flow rate based on the electric oil pump EP.

[0030] Here, specific situations in which the electric oil pump EP operates will be described.

[0031] In this embodiment, the electric oil pump EP is driven when auto downshift control, kickdown control, idling stop control, coast stop control, and the like are being executed.

[0032] The auto downshift control is a control for automatically downshifting the gear ratio of the transmission TM. Specifically, for example, when decelerating the vehicle 100, the auto downshift control is a control for returning the gear ratio of the variator VA to the lowest gear ratio just before the vehicle comes to a stop in order to ensure starting performance after the vehicle comes to a stop (hereinafter, returning the gear ratio of the variator VA to the lowest gear ratio is also referred to as "returning to low").

[0033] Low return is a gear change control that changes the gear ratio of the variator VA to the low side, i.e., in the direction of increasing the gear ratio, in response to a decrease in vehicle speed V, and is performed by downshifting the variator VA according to the gear change line (not shown) for coasting during coasting (a state in which the vehicle is traveling without fuel being supplied to the engine ENG), including during the coast stop control described below.

[0034] Furthermore, when the vehicle 100 suddenly decelerates, the secondary pulley SEC attempts to stop due to the braking force of the brakes. Meanwhile, the primary pulley PRI is subjected to inertial forces from the engine ENG, torque converter TC, and the like. If this inertial force is large, the clamping force may be insufficient, resulting in belt slippage. For this reason, the controller 2 quickly increases the line pressure PL to increase the secondary pulley pressure Psec. At this time, the rotational speed Ve of the engine ENG decreases, thereby reducing the flow rate of hydraulic oil supplied from the mechanical oil pump MP. Therefore, in this situation, the controller 2 operates the electric oil pump EP to quickly increase the line pressure PL and increase the secondary pulley pressure Psec, thereby preventing belt slippage. In this way, when the vehicle 100 suddenly decelerates, the secondary pulley pressure Psec is increased while being returned to low, increasing the required flow rate. As a result, the rotational speed of the electric oil pump EP increases.

[0035] The electric oil pump EP is also driven during kickdown control. Kickdown control is a gear change control that accelerates the vehicle 100 by significantly downshifting from the current gear ratio to the low side when the driver suddenly depresses the accelerator pedal. When kickdown control is executed, a high gear change speed is required, so the required flow rate increases. For this reason, the flow rate of hydraulic oil supplied from the mechanical oil pump MP cannot satisfy the required flow rate, so the electric oil pump EP is driven.

[0036] Coast stop control is a control that automatically stops the engine ENG while the vehicle 100 is coasting, reducing deceleration caused by engine friction and delaying the timing of fuel cut recovery (resumption of fuel supply to the engine ENG) due to a decrease in vehicle speed, thereby reducing fuel consumption. Specifically, when the accelerator pedal is released while the vehicle is traveling, the coast stop control stops the fuel supply to the engine ENG and cuts off the transmission of power between the engine ENG and the drive wheels DW by disengaging the forward clutch FWD / C, thereby automatically stopping the engine ENG (stopping the rotation of the engine ENG). This is similar to coasting with fuel cut control performed when the accelerator pedal is released in that the fuel supply to the engine ENG is stopped, but differs in that the power transmission path between the engine ENG and the drive wheels DW is cut off and the rotation of the engine ENG is stopped. Note that, in the fuel cut control performed during coasting with the accelerator pedal released, when the vehicle speed decreases and the rotational speed of the engine ENG, which is rotated by the drive wheels DW, decreases, the lockup clutch LU is released and fuel injection is resumed to maintain the engine ENG's independence.

[0037] When executing coast stop control, the controller 2 first checks whether the coast stop conditions (a) to (c) are satisfied: (a): The foot is released from the accelerator pedal (accelerator opening APO = 0) (b): The brake pedal is depressed (the brake force or brake pressure is greater than a specified value). (c): The vehicle speed V is equal to or lower than a predetermined low vehicle speed (e.g., 10 to 20 km / h) (predetermined vehicle speed V1). These conditions are, in other words, conditions for determining whether the driver intends to stop the vehicle. The controller 2 determines that the coast stop conditions are met when all of these conditions (a) to (c) are met. In addition to these, the remaining capacity of the battery (not shown), the cooling water temperature, etc. may also be included as conditions.

[0038] The lockup clutch LU is released when it crosses a lockup release line (not shown) set on the shift map from the high speed side or high rotation side to the low speed side or low rotation side.

[0039] The idling stop control is a control for stopping the idling of the engine ENG when predetermined conditions are met while the vehicle 100 is stopped. In executing the idling stop control, the controller 2 first checks whether the following idling stop conditions (d) to (f) are met: (d): The foot is released from the accelerator pedal (accelerator opening APO = 0) (e): The brake pedal is depressed (the brake force or brake pressure is greater than a specified value). (f): Vehicle speed V is 0 These conditions are, in other words, conditions for determining whether the driver intends to stop the vehicle. The controller 2 determines that the idling stop conditions are met when all of these conditions (d) to (f) are met. In addition to these, the remaining capacity of the battery (not shown), the cooling water temperature, etc. may also be included as conditions.

[0040] Incidentally, in the transmission TM, the check valve 27 provided on the suction side of the electric oil pump EP may malfunction and not open. If the check valve 27 does not open, the electric oil pump EP cannot draw hydraulic oil from the oil pan T, and as a result, cannot supply hydraulic oil to the line pressure oil passage 30. For this reason, if the check valve 27 malfunctions, the required flow rate must be met by the mechanical oil pump MP alone, or some other measure must be taken.

[0041] However, it is difficult to directly detect whether the check valve 27 has failed. Therefore, in this embodiment, the following method is used to determine whether the check valve 27 has failed. This method will be specifically described below.

[0042] When the electric oil pump EP is operating normally, there is a relationship between the rotation speed Vep of the electric oil pump EP and the drive current value Im of the motor M as shown by the straight line L in Fig. 2. Note that a normal state (usual state) means a state in which the inside of the electric oil pump EP (inside the pump chamber, inside the suction port, etc.) and the upstream and downstream sides of the electric oil pump EP are filled with hydraulic oil, and there are no abnormalities in any of the elements including the motor M.

[0043] As described above, when the check valve 27 does not open, the electric oil pump EP cannot draw hydraulic oil from the oil pan T. In this state, even if the electric oil pump EP rotates at a predetermined rotation speed Vepr, the load on the electric oil pump EP becomes lighter, and the drive current value Imr becomes smaller than the predetermined first current value Im1 (see FIG. 2).

[0044] Therefore, in this embodiment, based on these characteristics, it is determined whether or not the check valve 27 has failed, based on the rotation speed Vep of the electric oil pump EP and the drive current value Im of the motor M. Control related to a failure of the check valve 27 will be described below with reference to the flowcharts shown in FIGS. 3 to 6. First, the failure determination of the check valve 27 will be described with reference to FIG. 3. The control related to a failure of the check valve 27 described below is performed by executing a program stored in advance in the controller 2.

[0045] In step S1, it is determined whether the check valve 27 is normal (a state in which the check valve 27, which was closed, is opened by the operation of the electric oil pump EP and hydraulic oil is supplied to the electric oil pump). Specifically, the controller 2 determines whether the rotation speed Vep and drive current value Im of the electric oil pump EP are within the abnormal region S shown in FIG. 2 when the electric oil pump EP is operated. The abnormal region S is set to a region below the minimum value Imin (first current value Im1) of the drive current value Im of the motor M when the electric oil pump EP is operated in a normal drive state (when the check valve 27 is opened by the operation of the electric oil pump EP and the electric oil pump is operated in a state in which hydraulic oil is supplied to the electric oil pump), and where the rotation speed Vep is higher than that of the line L. If the operating state of the electric oil pump EP is within the abnormal region S set in this way, it can be determined that the load on the electric oil pump EP has become abnormally light. Therefore, in such a case, it is determined that the check valve 27 is abnormal (a state in which the check valve 27 does not open properly).

[0046] If it is determined in step S1 that the check valve 27 is normal, the process proceeds to END. On the other hand, if it is determined that the check valve 27 is not normal, the process proceeds to step S2.

[0047] In step S2, the abnormality flag is turned ON. Specifically, the controller 2 turns ON the abnormality flag. This abnormality flag is used for control, which will be described later.

[0048] In step S3, the electric oil pump EP is turned off. Specifically, the controller 2 prevents the electric oil pump EP from being driven thereafter, even if a situation arises in which the electric oil pump EP should be driven. At this time, a warning that can be understood by the driver or a maintenance worker may be issued.

[0049] Next, a description will be given of the control when there is a drive request for the electric oil pump EP.

[0050] As described above, the electric oil pump EP operates when the auto downshift control, the idling stop control, and the coast stop control are executed. First, the auto downshift control will be described with reference to FIG.

[0051] In step S11, it is determined whether or not the auto-down condition is met. Specifically, the controller 2 determines whether or not the low return condition is met.

[0052] If it is determined in step S11 that the auto-down condition is met, the process proceeds to step S12, and if it is determined in step S11 that the auto-down condition is not met, the process proceeds to END.

[0053] In step S12, it is determined whether the abnormality flag is ON or OFF. If the abnormality flag is OFF, the process proceeds to step S13, where auto-down control is executed. On the other hand, if the abnormality flag is ON, the process proceeds to step S14.

[0054] In step S14, the minimum rotation speed Vemin of the engine ENG is increased. Specifically, the controller 2 controls the minimum rotation speed Vemin of the engine ENG to be increased by a predetermined rotation speed compared to the normal state (a state in which the drive current value Im of the motor M does not fall below the minimum value Imin). In other words, the controller 2 increases the lower limit value of the rotation speed Ve of the engine ENG by the predetermined rotation speed. Note that the minimum rotation speed Vemin of the engine ENG is, for example, the idling rotation speed of the engine ENG.

[0055] In this way, by raising the minimum rotational speed Vemin of the engine ENG by a predetermined rotational speed, it is possible to increase the minimum supply flow rate of the mechanical oil pump MP when the engine ENG is rotating at the minimum rotational speed Vemin (for example, idling rotational speed). As a result, even if the electric oil pump EP is stopped, the required flow rate of hydraulic oil can be supplied by the mechanical oil pump MP alone. The predetermined rotational speed to be raised is set taking into consideration the discharge performance of the mechanical oil pump MP and the discharge performance of the electric oil pump EP.

[0056] After the minimum rotation speed Vemin of the engine ENG is set to increase in step S14, the process proceeds to step S13, where auto-down control is executed. In this case, the electric oil pump EP is not driven, so the required flow rate (required flow rate) is supplied only by the mechanical oil pump MP.

[0057] Next, the idling stop control will be described with reference to FIG.

[0058] In step S21, it is determined whether or not the idling stop condition is satisfied. Specifically, the controller 2 determines whether or not the above-mentioned idling stop control execution condition is satisfied.

[0059] If it is determined in step S21 that the idling stop condition is satisfied, the process proceeds to step S22, and if it is determined in step S21 that the idling stop condition is not satisfied, the process proceeds to END.

[0060] In step S22, it is determined whether the abnormality flag is ON or OFF. If the abnormality flag is OFF, the process proceeds to step S23, where idling stop control is executed. On the other hand, if the abnormality flag is ON, the process proceeds to END.

[0061] If the engine ENG is stopped while hydraulic oil cannot be supplied from the electric oil pump EP, it will be impossible to supply the hydraulic oil required by each element of the transmission TM. Therefore, in this embodiment, if the abnormality flag is ON, that is, if it is determined that the operating state of the electric oil pump EP is within the abnormality region S, the idling stop control is not executed. This makes it possible to supply the hydraulic oil required by the hydraulic control circuit 1 even when the vehicle 100 is stopped.

[0062] Next, the coast stop control will be described with reference to FIG.

[0063] In step S31, it is determined whether or not the coast stop condition is satisfied. Specifically, the controller 2 determines whether or not the coast stop control execution condition described above is satisfied.

[0064] If it is determined in step S31 that the coast stop condition is met, the process proceeds to step S32, and if it is determined in step S31 that the coast stop condition is not met, the process proceeds to END.

[0065] In step S32, it is determined whether the abnormality flag is ON or OFF. If the abnormality flag is OFF, the process proceeds to step S33, where coast stop control is executed. On the other hand, if the abnormality flag is ON, the process proceeds to END.

[0066] If the engine ENG is stopped while hydraulic oil cannot be discharged from the electric oil pump EP, the required hydraulic oil cannot be supplied. Therefore, in this embodiment, if the abnormality flag is ON, that is, if it is determined that the operating state of the electric oil pump EP is within the abnormality region S, the coast stop control is not executed. This allows the hydraulic control circuit 1 to supply the required hydraulic oil even when the vehicle 100 is coasting. This makes it possible to reliably execute low return and other operations.

[0067] In the above embodiment, the abnormal region S is set to a region equal to or less than the minimum value Imin (first current value Im1) of the drive current value Im of the motor M when the electric oil pump EP is driven in a normal drive state, and a region where the rotation speed Vep is higher than that of the line L. However, the abnormal region may also be set to a region S1 (hatched portion in FIG. 2 ) equal to or less than Im2, which is a predetermined amount smaller than the minimum value Imin (first current value Im1), and where the rotation speed Vep of the electric oil pump EP is higher than the normally used rotation speed Vep1. By setting the abnormal region to such a region S1, errors due to noise and the like can be tolerated, and erroneous determination can be prevented.

[0068] In this way, in this embodiment, a failure of the check valve 27 is detected from the operating state of the electric oil pump EP, and if a failure occurs in the check valve 27, control can be performed so that the flow rate of the hydraulic oil that controls the transmission TM is not insufficient. In other words, according to this embodiment, the transmission TM can be appropriately controlled even when the check valve 27 does not open.

[0069] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0070] (1), (8), (11) Vehicle 100 is equipped with a transmission TM having a mechanical oil pump MP (first oil pump) driven by rotation of an engine ENG (drive source) that drives drive wheels DW, and an electric oil pump EP (second oil pump) that has a check valve 27 on its intake side and is driven by a motor M. A controller 2 (control device) that controls vehicle 100 increases the minimum rotation speed Vemin of the engine ENG (drive source) when performing auto downshift control to automatically downshift the gear ratio of transmission TM, when the minimum value Imin of the drive current value Im of motor M when the electric oil pump EP (second oil pump) is driven in a normal driving state is defined as a first current value Im1, and when the drive current value Im of motor M becomes lower than the first current value Im1 when the electric oil pump EP (second oil pump) is driven.

[0071] With this configuration, if the drive current value Im of the motor M becomes lower than the first current value Im1 when the electric oil pump EP (second oil pump) is driven, that is, if the check valve 27 is malfunctioning, the minimum rotation speed Vemin of the engine ENG is increased by a predetermined rotation speed when auto downshift control is executed. This makes it possible to increase the minimum supply flow rate of the mechanical oil pump MP when the engine ENG is rotating at the minimum rotation speed Vemin (e.g., idling rotation speed). Therefore, even if the electric oil pump EP is stopped, the required flow rate of hydraulic oil can be supplied by the mechanical oil pump MP alone. Therefore, even if the check valve 27 does not open, delays in downshifting can be suppressed and the transmission TM can be appropriately controlled.

[0072] (2) In the vehicle 100, when the drive current value Im of the motor M becomes equal to or less than the second current value Im2, which is a predetermined amount smaller than the first current value Im1, the minimum rotation speed Vemin of the drive source (engine ENG) is increased when performing auto-downshift control compared to when the drive current value Im of the motor M is equal to or greater than the first current value Im1.

[0073] In this configuration, errors due to noise and the like can be tolerated, making it possible to prevent erroneous determinations.

[0074] (3), (9), (12) Vehicle 100 is equipped with a transmission TM having a mechanical oil pump MP (first oil pump) driven by the rotation of an engine ENG (drive source) that drives drive wheels DW, and an electric oil pump EP (second oil pump) that has a check valve 27 on its intake side and is driven by a motor M. When the minimum value Imin of the drive current value Im of motor M when the electric oil pump EP (second oil pump) is driven in a normal drive state is defined as a first current value Im1, a controller 2 (control device) that controls vehicle 100 does not execute idling stop control that automatically stops engine ENG (drive source) while the vehicle is stopped if the drive current value Im of motor M becomes lower than first current value Im1 when the electric oil pump EP (second oil pump) is driven.

[0075] In this configuration, if the drive current value Im of the motor M becomes lower than the first current value Im1 when the electric oil pump EP (second oil pump) is driven, that is, if the check valve 27 is malfunctioning, the idling stop control is not executed. This allows the mechanical oil pump MP to supply the required flow rate of hydraulic oil when the vehicle 100 is stopped. Therefore, the transmission TM can be appropriately controlled even when the check valve 27 does not open.

[0076] (4) In the vehicle 100, when the drive current value Im of the motor M is equal to or less than the second current value Im2 that is smaller by a predetermined amount than the first current value Im1, the idling stop control is not executed.

[0077] In this configuration, errors due to noise and the like can be tolerated, making it possible to prevent erroneous determinations.

[0078] (5), (10), (13) Vehicle 100 is equipped with a transmission TM having a mechanical oil pump MP (first oil pump) driven by rotation of an engine ENG (drive source) that drives drive wheels DW, and an electric oil pump EP (second oil pump) that has a check valve 27 on its intake side and is driven by a motor M. When the minimum value Imin of the drive current value Im of motor M when the electric oil pump EP (second oil pump) is driven in a normal drive state is defined as a first current value Im1, a controller 2 (control device) that controls vehicle 100 automatically stops engine ENG (drive source) while traveling and does not execute coast stop control that interrupts the transmission of power between engine ENG (drive source) and drive wheels DW.

[0079] In this configuration, if the drive current value Im of the motor M becomes lower than the first current value Im1 when the electric oil pump EP (second oil pump) is driven, that is, if the check valve 27 has failed, the coast stop control is not executed. As a result, when the vehicle 100 coasts, the required flow rate of hydraulic oil can be supplied by the mechanical oil pump MP. Therefore, even if the check valve 27 does not open, the transmission TM can be appropriately controlled.

[0080] (6) In the vehicle 100, when the drive current value Im of the motor M becomes equal to or less than the second current value Im2 that is smaller by a predetermined amount than the first current value Im1, the coast stop control is not executed.

[0081] In this configuration, errors due to noise and the like can be tolerated, making it possible to prevent erroneous determinations.

[0082] (7) In the vehicle 100, when the drive current value Im of the motor M becomes equal to or less than the second current value Im2, the electric oil pump EP (second oil pump) is no longer driven.

[0083] Even if the check valve 27 malfunctions, a small amount of hydraulic oil may be supplied from the electric oil pump EP (second oil pump). In such a situation, there is a risk that control may become unstable. Therefore, in such a case, the control can be stabilized by stopping the operation of the electric oil pump EP (second oil pump).

[0084] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0085] The engine ENG may be a diesel engine.

[0086] In the above embodiment, the vehicle is described as being capable of executing all of the auto-down control, the idling stop control, and the coast stop control, but the vehicle may be any vehicle capable of executing any one of these.

[0087] Furthermore, the transmission TM is not limited to a continuously variable transmission, but may be a stepped transmission. [Explanation of symbols]

[0088] 100 vehicles 1 Hydraulic control circuit 2 Controller (control device) 27 Check valve ENG Engine (power source) DW drive wheel Medium motor TM transmission MP Electric Oil Pump (1st Oil Pump) EP mechanical oil pump (second oil pump)

Claims

1. A vehicle control device for controlling a vehicle equipped with a transmission including a first oil pump driven by rotation of a drive source that drives drive wheels, and a second oil pump provided with a check valve on an intake side and driven by a motor, When the minimum value of the drive current value of the motor when the second oil pump is driven in a normal drive state is defined as a first current value, A vehicle control device that performs a fault determination when the second oil pump is driven, turns on an abnormality flag if the drive current value of the motor becomes lower than the first current value, and when executing auto-downshift control to automatically downshift the gear ratio of the transmission, determines whether the abnormality flag is on or off based on the fault determination performed separately from the auto-downshift control, and increases the minimum rotational speed of the drive source when the abnormality flag is on more than when the flag is off.

2. 2. The vehicle control device according to claim 1, A vehicle control device that, when executing the auto-downshift control, increases the minimum rotational speed of the drive source when the drive current value of the motor becomes equal to or less than a second current value that is a predetermined amount smaller than the first current value, compared to when the drive current value of the motor is equal to or greater than the first current value.

3. 3. The vehicle control device according to claim 2, A vehicle control device that does not drive the second oil pump when the drive current value of the motor becomes equal to or less than the second current value.

4. A vehicle control method for controlling a vehicle equipped with a transmission having a first oil pump driven by rotation of a drive source that drives drive wheels, and a second oil pump provided with a check valve on an intake side and driven by a motor, comprising: When the minimum value of the drive current value of the motor when the second oil pump is driven in a normal drive state is defined as a first current value, A vehicle control method comprising: performing a fault determination when the second oil pump is driven; turning on an abnormality flag if the drive current value of the motor becomes lower than the first current value; and, when executing auto-downshift control to automatically downshift the gear ratio of the transmission, determining whether the abnormality flag is on or off based on the fault determination performed separately from the auto-downshift control; and increasing the minimum rotational speed of the drive source when the abnormality flag is on more than when the flag is off.

5. A program executable by a computer for controlling a vehicle equipped with a transmission including a first oil pump driven by rotation of a drive source that drives drive wheels, and a second oil pump provided with a check valve on the intake side and driven by a motor, When the minimum value of the drive current value of the motor when the second oil pump is driven in a normal drive state is defined as a first current value, A program that causes the computer to execute a procedure of: performing a fault determination when the second oil pump is driven; turning on an abnormality flag if the drive current value of the motor becomes lower than the first current value; when executing auto-downshift control that automatically downshifts the gear ratio of the transmission, determining whether the abnormality flag is on or off based on the fault determination made separately from the auto-downshift control; and increasing the minimum rotational speed of the drive source when the abnormality flag is on more than when the flag is off.

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