Vehicle control devices, vehicle control methods and procedures

Abstract

The vehicle control device of the present invention can suppress false judgments related to abnormal judgments of the electric oil pump, and prevent deterioration of fuel efficiency. When the drive current value of the electric motor becomes higher than the maximum value of the electric motor drive current value when driving the second oil pump under normal driving conditions, the vehicle control device, during automatic downshift control that automatically downshifts the transmission ratio, increases the minimum speed of the drive source compared to the case where the electric motor drive current value is below the maximum value. Furthermore, when the main pressure generated by the oil pressure supplied from the first and second oil pumps is higher than a predetermined value, the minimum speed of the drive source does not increase during automatic downshift control, even when the electric motor drive current value becomes higher than the maximum value when driving the second oil pump.

Description

Technical Field

[0001] This invention relates to a vehicle control device, a vehicle control method, and a computer-executable program for controlling a vehicle. Background Technology

[0002] Patent document 1 discloses a hybrid vehicle comprising: an engine, two drive electric motors, a mechanical oil pump that rotates together with the engine and discharges working oil used in the power transmission device, and an electric oil pump that discharges working oil by rotating via a dedicated electric motor for the oil pump.

[0003] In the hybrid vehicle described in Patent Document 1, when driving in electric motor mode, if the electric oil pump malfunctions and is in a state of insufficient capacity, driving based on both drive motors is prohibited. Instead, the vehicle is driven by one drive motor, and the mechanical oil pump is rotated by the other drive motor. Thus, in the hybrid vehicle described in Patent Document 1, even if the electric oil pump malfunctions and is in a state of insufficient capacity, the necessary flow of working oil can be adequately ensured through the power transmission device.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-66369

[0007] The problem that the invention aims to solve

[0008] Compared to a mechanical oil pump driven by an engine, an electric oil pump driven by an electric motor has a lower maximum discharge pressure. Therefore, for example, when the main pressure (line pressure) is high, the electric oil pump may be considered faulty because it cannot discharge working oil.

[0009] When this is determined to be a malfunction of the electric oil pump, the electric oil pump will stop driving, and only the mechanical oil pump will supply working oil, which may deteriorate fuel efficiency. Summary of the Invention

[0010] The present invention was made in view of the following problem, and its purpose is to suppress false judgments related to the abnormal judgment of the electric oil pump EP, and prevent the deterioration of fuel efficiency.

[0011] One aspect of the present invention provides a vehicle with a transmission comprising: a first oil pump driven by the rotation of a drive source that drives drive wheels, and a second oil pump driven by an electric motor. Furthermore, when the drive current value of the electric motor when driving the second oil pump becomes higher than the maximum value of the drive current value of the electric motor when driving the second oil pump under normal driving conditions, the vehicle control device, during automatic downshift control that automatically downshifts the transmission gear ratio, increases the minimum rotational speed of the drive source compared to the case where the drive current value of the electric motor is below the maximum value. Conversely, when the main pressure (line pressure) generated by the oil pressure supplied from the first and second oil pumps is higher than a predetermined value, the minimum rotational speed of the drive source is not increased during automatic downshift control, even when the drive current value of the electric motor when driving the second oil pump is higher than the maximum value.

[0012] Furthermore, in other embodiments of the present invention, the vehicle includes a transmission comprising: a first oil pump driven by the rotation of a drive source that drives the drive wheels, and a second oil pump driven by an electric motor. Additionally, the vehicle control device controlling the vehicle does not perform idle stop control (automatically stopping the drive source when the vehicle is stopped) if the drive current value of the electric motor when driving the second oil pump becomes higher than the maximum value of the drive current value of the electric motor when driving the second oil pump under normal driving conditions; however, if the main pressure generated by the oil pressure supplied from the first and second oil pumps is higher than a predetermined value, idle stop control is performed even if the drive current value of the electric motor when driving the second oil pump is higher than the maximum value.

[0013] In another aspect of the present invention, a vehicle includes a transmission comprising: a first oil pump driven by the rotation of a drive source that drives the drive wheels, and a second oil pump driven by an electric motor. Furthermore, the vehicle control device controlling the vehicle does not perform coasting stop control—which automatically stops the drive source and cuts off power transmission between the drive source and the drive wheels during driving—when the drive current value of the electric motor when driving the second oil pump becomes higher than the maximum value of the drive current value of the electric motor when driving the second oil pump under normal driving conditions. However, when the main pressure generated by the oil pressure supplied from the first and second oil pumps is higher than a predetermined value, coasting stop control is performed even when the drive current value of the electric motor when driving the second oil pump is higher than its maximum value.

[0014] Invention Effects

[0015] These methods can suppress false judgments related to abnormal determinations of electric oil pumps and prevent deterioration of fuel efficiency. Attached Figure Description

[0016] Figure 1This is a schematic structural diagram of a vehicle equipped with the hydraulic control circuit of the transmission according to this embodiment.

[0017] Figure 2 This is a flowchart illustrating the control process for determining abnormalities in the electric oil pump of this embodiment.

[0018] Figure 3 This is a diagram used to illustrate the abnormality detection area of ​​the electric oil pump in this embodiment.

[0019] Figure 4A This is a diagram showing the abnormal regions in the relationship between the drive current value and the actual rotational speed in this embodiment.

[0020] Figure 4B This is a diagram showing the abnormal regions in the relationship between the indicated speed and the actual speed in this embodiment.

[0021] Figure 5 This is a flowchart of the automatic downshift control.

[0022] Figure 6 This is a flowchart of the idle stop control.

[0023] Figure 7 This is a flowchart of the coasting stop control. Detailed Implementation

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic structural diagram of vehicle 100. Vehicle 100 includes: engine ENG, hydraulic torque converter TC, forward / reverse switching mechanism SWM, and transmission mechanism VA. In vehicle 100, the transmission TM is a belt-type continuously variable transmission with hydraulic torque converter TC, forward / reverse switching mechanism SWM, and transmission mechanism VA.

[0026] 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 transmission mechanism VA. In other words, the torque converter TC, the forward / reverse switching mechanism SWM, and the transmission mechanism VA are located on the power transmission path connecting the engine ENG and the drive wheels DW.

[0027] The torque converter TC transmits power via fluid. In the torque converter TC, the power transmission efficiency can be improved by engaging a lock-up clutch LU.

[0028] The forward / reverse switching mechanism (SWM) is located on the power transmission path connecting the engine (ENG) and the transmission mechanism (VA). The SWM switches the vehicle 100 between forward and reverse by changing the direction of the input rotation. The SWM includes a forward clutch (FWD / C) engaged when forward gear (D) is selected, and a reverse brake (REV / B) engaged when reverse gear (R) is selected. When the forward clutch (FWD / C) and the reverse brake (REV / B) are released, the transmission TM enters neutral, i.e., the power is cut off.

[0029] The transmission mechanism VA constitutes a belt-type continuously variable transmission (CVT), which includes 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, used as hydraulic pressure to drive the primary pulley PRI, is supplied to the primary pulley PRI from the hydraulic control circuit 1 described later, and a secondary pulley pressure Psec, used as hydraulic pressure to drive the secondary pulley SEC, is supplied to the secondary pulley SEC.

[0030] The transmission TM is configured to also include: a mechanical oil pump MP, an electric oil pump EP, an electric motor M, an oil pressure control circuit 1, a check valve 25, and a check valve 26. The mechanical oil pump MP supplies working oil drawn from the oil pan T to the oil pressure control circuit 1. The mechanical oil pump MP is driven by the engine ENG. The electric oil pump EP is driven by the electric motor M. The electric oil pump EP supplies working oil drawn from the oil pan T to the oil pressure control circuit 1 together with or separately from the mechanical oil pump MP. The electric oil pump EP is provided to assist the mechanical oil pump MP. The electric oil pump EP is configured to include an electric motor M.

[0031] The hydraulic control circuit 1 consists of multiple flow paths and multiple hydraulic control valves, which regulate the pressure of the working oil supplied from the mechanical oil pump MP or the electric oil pump EP before supplying it to various parts of the transmission TM.

[0032] The operation of the engine (ENG) and transmission (TM) is controlled by controller 2, which is a control device. Controller 2 includes an engine controller (not shown) and a transmission controller (not shown). Both are configured as electronic control units, consisting of a microcomputer equipped with a central processing unit (CPU), various storage devices such as RAM and ROM, and input / output interfaces. Furthermore, the engine controller and transmission controller are interconnected via a CAN bus. Controller 2 reads and executes various programs stored in ROM or similar media via the CPU to perform various processes. The various programs executed by controller 2 can be, for example, programs stored in non-transitory storage media such as CD-ROM.

[0033] The controller 2 (engine controller) receives detection signals from an operation status sensor that detects the operating status of the engine (ENG). Based on the operating status, it performs prescribed calculations to set the fuel injection quantity, fuel injection timing, and ignition timing of the engine (ENG). The engine (ENG) controls its speed, torque, etc., based on instructions from the controller 2 (engine controller). The operation status sensors include an accelerator sensor that detects the driver's input to the accelerator pedal (hereinafter referred to as "accelerator opening"), a speed sensor that detects the engine (ENG) speed (Ve), and a coolant temperature sensor that detects the engine coolant temperature.

[0034] Additionally, controller 2 (transmission controller) receives detection signals from various sensors that detect the operating status of the transmission TM, and controls the operation of hydraulic control circuit 1 and electric hydraulic pump EP based on these signals. Hydraulic control circuit 1 performs hydraulic pressure control on the lock-up clutch LU, forward clutch FWD / C, reverse brake REV / B, primary pulley PRI, secondary pulley SEC, etc., based on instructions from controller 2.

[0035] The check valve 25 allows working oil to flow from the mechanical oil pump MP towards the hydraulic control circuit 1 while simultaneously preventing the flow of working oil from the hydraulic control circuit 1 towards the mechanical oil pump MP. This prevents the main pressure (line pressure) PL from acting on the mechanical oil pump MP when it stops.

[0036] The check valve 26 allows working oil to flow from the electric hydraulic pump EP towards the hydraulic control circuit 1 while simultaneously preventing the flow of working oil from the hydraulic control circuit 1 towards the electric hydraulic pump EP. This prevents the electric hydraulic pump EP from reversing due to the main pressure (pipeline pressure) PL acting on it when the electric hydraulic pump EP stops.

[0037] A check valve 27 is provided between the electric hydraulic pump EP and the oil pan T. The check valve 27 prevents working oil from returning to the oil pan T from inside the electric hydraulic pump EP and through the flow path on the suction side of the electric hydraulic pump EP when the electric hydraulic pump EP stops. This prevents air from entering the electric hydraulic pump EP, in other words, it prevents insufficient intake of working oil in the electric hydraulic pump EP and suppresses the delay in oil pressure rise when the electric hydraulic pump EP operates.

[0038] Next, the operating modes of the mechanical oil pump MP and the electric oil pump EP will be explained.

[0039] The controller 2 switches the operating modes of the mechanical oil pump MP and the electric oil pump EP according to the operating status of the vehicle 100. In this embodiment, the operating modes are: MP mode, in which the mechanical oil pump MP is driven only by the engine ENG; EP mode, in which the electric oil pump EP is driven only; and TDP mode, in which both the mechanical oil pump MP and the electric oil pump EP are driven.

[0040] When the engine speed (Ve) of the ENG is high, the MP mode is selected. Specifically, this mode is selected when the flow rate required by the hydraulic equipment mounted on the vehicle 100 (hereinafter referred to as "required flow rate") can be provided by the discharge flow rate of the mechanical oil pump MP. The discharge flow rate of the mechanical oil pump MP is proportional to the engine speed (Ve) of the ENG. Therefore, when the engine speed (Ve) of the ENG is high, the required flow rate can be provided solely by the power of the engine ENG, i.e., based on the discharge flow rate of the mechanical oil pump MP. In MP mode, the electric oil pump EP remains stationary.

[0041] Select EP mode when the engine (ENG) is stopped. When performing idle stop, coasting stop, or similar actions, the mechanical oil pump (MP) stops rotating because the engine (ENG) stops. Therefore, when the engine (ENG) stops rotating, the controller 2 drives the electric motor (M) to drive the electric oil pump (EP). This allows the required flow rate to be provided based on the discharge flow rate of the electric oil pump (EP).

[0042] In cases where the required flow rate cannot be provided solely based on the exhaust flow rate of the engine ENG, specifically when the engine ENG speed Ve is low, the TDP mode is selected. As mentioned above, when only the engine ENG is driven, the exhaust flow rate of the mechanical oil pump MP is proportional to the engine ENG speed Ve. Therefore, when the engine ENG speed Ve is low, the required flow rate cannot be provided solely based on the exhaust flow rate of the mechanical oil pump MP. Consequently, the controller 2 drives the electric motor M, which in turn drives the electric oil pump EP. Thus, the required flow rate, which is insufficient based solely on the exhaust flow rate of the mechanical oil pump MP, can be provided using the exhaust flow rate of the electric oil pump EP.

[0043] Here, we will explain the specific operation of the electric oil pump EP.

[0044] In this embodiment, the electric oil pump EP is driven when performing automatic downshift control, rapid downshift control, idle stop control, and coasting stop control.

[0045] Automatic downshift control is a control that automatically downshifts the gear ratio of the transmission TM. Specifically, for example, when the vehicle is decelerating from 100 km / h, in order to ensure the vehicle's starting ability after stopping, the control returns the gear ratio of the transmission mechanism VA to the lowest gear ratio just before the vehicle stops (hereinafter, the case of returning the gear ratio of the transmission mechanism VA to the lowest gear ratio is also referred to as "return to low gear").

[0046] Returning to a lower gear is a transmission control that changes the gear ratio of the transmission mechanism VA to the lower gear side, i.e., the direction of increasing the gear ratio, based on the decrease in vehicle speed V. In coasting driving (the state of driving without supplying fuel to the engine ENG) including the coasting stop control described later, the transmission mechanism VA is downshifted along the gear shift line (not shown) during coasting driving.

[0047] Furthermore, when the vehicle decelerates rapidly to 100 km / h, the secondary pulley SEC stops due to the braking force of the brakes. On the other hand, the inertial forces of the engine ENG and torque converter TC act on the primary pulley PRI. If this inertial force is large, insufficient clamping force may cause belt slippage. Therefore, controller 2 rapidly increases the main pressure PL, causing the secondary pulley pressure Psec to rise. At this time, because the engine ENG speed Ve decreases, the flow rate of working oil supplied from the mechanical oil pump MP decreases. Therefore, under these conditions, controller 2 activates the electric oil pump EP, rapidly increasing the main pressure PL and the secondary pulley pressure Psec, thereby preventing belt slippage. During such a rapid deceleration of the vehicle to 100 km / h, the secondary pulley pressure Psec rises while simultaneously shifting to a lower gear, thus requiring a larger flow rate. Therefore, the speed of the electric oil pump EP increases.

[0048] Additionally, the electric oil pump EP is also activated during rapid downshift control. Rapid downshift control refers to a gear control mechanism that, when the driver rapidly depresses the accelerator pedal, significantly downshifts from the current gear ratio to a lower gear, accelerating the vehicle to 100 km / h. During rapid downshift control, a higher flow rate is required due to the faster gear changes. Therefore, the flow rate of working oil supplied from the mechanical oil pump MP is insufficient to meet the required flow, thus activating the electric oil pump EP.

[0049] Coasting stop control refers to the automatic stopping of the engine (ENG) during vehicle travel at 100° of inertia. This reduces deceleration caused by friction within the ENG and delays the resumption of fuel cutoff (restarting fuel supply to the ENG) due to reduced vehicle speed, thereby suppressing fuel consumption. Specifically, during driving, when the accelerator is disengaged, fuel supply to the ENG is stopped, and the power transmission between the ENG and drive wheels (DW) is cut off by releasing the forward clutch (FWD / C), thus automatically stopping the ENG (stopping its rotation). Compared to coasting driving based on fuel cutoff control performed when the accelerator is disengaged, it is the same in stopping fuel supply to the ENG, but differs in cutting off the power transmission path between the ENG and drive wheels (DW) to stop the ENG's rotation. Furthermore, in fuel cutoff control performed during coasting driving with the accelerator disengaged, when the vehicle speed decreases and the ENG's speed driven by the drive wheels (DW) decreases, the lock-up clutch (LU) is released to maintain the ENG's independent state, and fuel injection resumes.

[0050] When performing coasting stop control, controller 2 first determines the following coasting stop conditions (a) to (c):

[0051] (a): Foot leaves the accelerator pedal (accelerator opening APO = 0)

[0052] (b): The brake pedal is depressed (brake force or brake pressure is above the specified value).

[0053] (c): The vehicle speed V is below the specified low speed (e.g., 10-20 km / h) (specified speed Vv). In other words, these conditions are used to determine whether the driver intends to stop. If all of these conditions (a) to (c) are met, the controller 2 determines that the coasting stop condition has been met. In addition, conditions such as the remaining capacity of the battery (not shown) and the coolant temperature may also be included.

[0054] Additionally, the lock-up clutch LU is released when the lock-up release line (not shown) set on the transmission map is traversed from the high-speed side or high-speed rotation side to the low-speed side or low-speed rotation side.

[0055] Idle stop control refers to the control that stops the engine ENG from idling when specified conditions are met when the vehicle comes to a complete stop. When executing idle stop control, controller 2 first determines the idle stop conditions (d) to (f) as shown below:

[0056] (d): Foot leaves the accelerator pedal (accelerator opening APO = 0)

[0057] (e): The brake pedal is depressed (brake force or brake pressure is above the specified value).

[0058] (f): Vehicle speed V is 0.

[0059] These conditions, in other words, are used to determine whether the driver intends to stop. Controller 2 determines that the idling stop condition is met if all of these conditions (d) to (f) are met. In addition, conditions such as the remaining capacity of the battery (not shown) and the coolant temperature may also be included.

[0060] However, when the main pressure PL is higher than the specified value PL1, working oil may not be supplied even if the electric oil pump EP is driven. Specifically, for example, when the main pressure PL is higher than the pressure that the electric oil pump EP can discharge (maximum discharge pressure), working oil may not be supplied even if the maximum value of the drive current Im that can supply the electric oil pump EP is reached.

[0061] Under these circumstances, since the drive current value Im of the electric oil pump EP remains high, the actual speed Vepr (actual speed Vepr) will continue to deviate from the indicated speed Vepi, thus the controller 2 determines that the electric oil pump EP has malfunctioned. In the event of a malfunction in the electric oil pump EP, the controller 2 stops the electric oil pump EP and subsequently ceases to execute the aforementioned idle stop control or coasting stop control.

[0062] However, if the main pressure PL is higher than the specified value PL1, it exceeds the performance of the electric oil pump EP. Therefore, the electric oil pump EP may simply be unable to drive, not malfunction. Thus, if the electric oil pump EP is deemed abnormal and stopped under such circumstances, and only the mechanical oil pump MP is used to supply working oil afterwards, fuel efficiency may deteriorate.

[0063] Therefore, in this embodiment, when the main pressure PL is higher than the specified value PL1, in order to suppress false judgments related to the abnormal diagnosis of the electric oil pump EP, abnormal diagnosis of the electric oil pump EP is not performed. Below, refer to... Figures 2-7 This embodiment describes the control of the electric oil pump EP in detail. Figure 2 This is a flowchart illustrating the control process for diagnosing abnormalities in the electric oil pump EP. Furthermore, the control of the electric oil pump EP, as described below, is performed by executing a program pre-stored in the controller 2.

[0064] In step S1, it is determined whether the main pressure PL is higher than the specified value PL1. Specifically, the controller 2 determines this by the main pressure sensor 31 (refer to...). Figure 1 Is the detected main pressure PL higher than the specified value PL1? Here, the specified value PL1 will be explained.

[0065] In this embodiment, the specified value PL1 is a threshold used to determine whether to perform an abnormality diagnosis. Specifically, the specified value PL1 is equivalent to... Figure 3 Line segment L1 in the diagram is a predetermined value based on the rotational speed Vep. Additionally, Figure 3 The pressure PLmax is the maximum discharge pressure (upper limit of the discharge pressure) of the electric oil pump EP.

[0066] Even if the main pressure PL is below the pressure PLmax, if the indicated speed Vepi increases, even if the drive current value Im rises to the upper limit of the supply, the working oil cannot be supplied by the electric oil pump EP due to the relationship between the discharge pressure and the discharge flow rate (this situation is achieved). Therefore, in this embodiment, if there is an operating point in the region where the main pressure PL is below the discharge pressure PLmax of the electric oil pump EP and below the speed achievable by each main pressure PL (i.e., below the specified value PL1 (main pressure shown by line segment L1), the controller 2 performs an abnormality diagnosis on the electric oil pump EP. In contrast, if there is an operating point in region R2 outside region R1, i.e., the operating point of the electric oil pump EP is not in region R1, as described above, there is a possibility that the electric oil pump EP cannot be driven temporarily, so the controller 2 does not perform an abnormality diagnosis on the electric oil pump EP.

[0067] In step S1, if the controller 2 determines that the main pressure PL is higher than the specified value PL1, the process proceeds to the end (END). That is, if the main pressure PL is higher than the specified value PL1, the controller 2 does not perform abnormal diagnosis of the electric oil pump EP. Conversely, if the controller 2 determines that the main pressure PL is lower than the specified value PL1, the process proceeds to step S2.

[0068] In step S2, it is determined whether the electric oil pump EP is malfunctioning. The indicated speed Vepi of the electric oil pump EP corresponds to the actual current value (drive current value Im) applied to the motor M. Therefore, in this embodiment, as shown in FIG4(A), based on the drive current value Im detected by the current sensor (not shown) and the speed sensor 32 (see reference 32), the speed is determined to be malfunctioning. Figure 1 The relationship between the actual rotational speed (Vepr) detected and the electric oil pump (EP) is used to determine whether the pump is malfunctioning.

[0069] As shown in Figure 4(A), when the electric oil pump EP is driven in normal condition, there is a linear relationship, L2, between the drive current value Im of the motor M and the actual speed Vepr of the electric oil pump EP. Furthermore, normal condition (ordinary condition) refers to the state where the actual speed Vepr of the electric oil pump EP is almost identical to the indicated speed Vepi, meaning that there are no abnormalities in any of the components including the electric oil pump EP and the motor M.

[0070] For example, when a foreign object or other object gets stuck in the sliding part of the electric oil pump EP, causing an increase in rotational resistance, the drive current value Im is higher than normal. Therefore, in this embodiment, if the drive current value Im of the motor M is higher than the maximum allowable value Imax of the drive current value Im at its rotational speed Vepr for a specified period of time when driving the electric oil pump EP, the electric oil pump EP is determined to be abnormal.

[0071] Specifically, when the electric oil pump EP is driven, the controller 2 determines whether the operating point of the electric oil pump EP (the rotational speed Vep of the electric oil pump EP and the drive current value Im of the motor M) is within the abnormal region S shown in Figure 4(A). The straight line L3 shown in Figure 4(A) is the line connecting the maximum value Imax of the drive current value Im that is allowed (can be judged as normal) for each actual rotational speed Vper of the electric oil pump EP.

[0072] To illustrate this abnormality diagnosis, a specific example is given: when the actual rotational speed Vper detected by the speed sensor 32 is speed V2, under normal conditions (normal state), the drive current value Im becomes Im1 (point P1).

[0073] In contrast, for example, when the actual rotational speed Vper is the same as the speed V2, if the drive current value Im is higher than the maximum allowable drive current value Im3 (point P3) (point P2), the controller 2 determines that the electric oil pump EP is abnormal.

[0074] In this embodiment, the abnormal region S is defined as the region divided by the lowest value Imin of the driving current value Im of the straight line L3 and the motor M.

[0075] In step S2, if the operating point of the electric oil pump EP is determined to be within the abnormal region S, the controller 2 determines that the electric oil pump EP is abnormal. If the electric oil pump EP is determined to be abnormal, then proceed to step S3. Conversely, if the operating point of the electric oil pump EP is not within the abnormal region S, the controller 2 determines that the electric oil pump EP is not abnormal and proceeds to the end (END).

[0076] In addition, abnormalities of the electric oil pump EP can also be determined by whether the speed difference ΔVpe between the indicated speed Vepi and the actual speed (actual speed Vepr) of the electric oil pump EP has been above a specified value V1 for a specified time T (about a few seconds).

[0077] If the speed difference ΔVpe (refer to Figure 4(B)) between the indicated speed Vepi and the actual speed Vepr is greater than or equal to a predetermined value V1 for a predetermined time T (approximately several seconds), it can be considered that a foreign object or other object may be stuck in the sliding part of the electric oil pump EP, causing an increase in rotational resistance, or that the motor M may malfunction, thus determining it to be an abnormality. Furthermore, the predetermined value V1 is, for example, set to a value equivalent to the indicated speed Vepi multiplied by a predetermined coefficient α, or a fixed value.

[0078] In step S3, the fault flag is set to ON. Specifically, controller 2 sets the fault flag to ON. This fault flag is used for control as described later.

[0079] In step S4, the electric hydraulic pump EP is disconnected (OFF). Specifically, even if the controller 2 subsequently becomes capable of driving the electric hydraulic pump EP, it will not drive the electric hydraulic pump EP. At this time, a warning can also be issued to inform the driver or maintenance personnel.

[0080] Next, the control method for situations where there is a drive requirement for the electric oil pump EP will be explained.

[0081] As described above, the electric oil pump EP operates when performing automatic downshift control, rapid downshift control, idle stop control, and coasting stop control. First, refer to... Figure 5 The automatic downshift control is explained.

[0082] In step S11, it is determined whether the automatic downshift condition is met. Specifically, the controller 2 determines whether the return to a lower gear condition or the emergency downshift control execution condition is met.

[0083] In step S11, if the automatic downshift condition is determined to be met, proceed to step S12; if the automatic downshift condition is determined to be unmet in step S11, proceed to end (END).

[0084] In step S12, it is determined whether the fault flag is ON or OFF. If the fault flag is OFF, proceed to step S13 and execute automatic downshift control. Conversely, if the fault flag is ON, proceed to step S14.

[0085] In step S14, the minimum engine speed Vemin of the engine ENG is increased. Specifically, the controller 2 controls the engine ENG's minimum engine speed Vemin to increase by a predetermined amount compared to the normal state (when the drive current value Im of the electric motor M is not below the minimum value Im). In other words, the controller 2 increases the lower limit of the engine ENG's speed Ve by a predetermined amount. Furthermore, the engine ENG's minimum engine speed Vemin is, for example, the engine ENG's idle speed.

[0086] In this way, by increasing the minimum engine speed (Vemin) of the engine (ENG) by a specified amount, the minimum supply flow of the mechanical oil pump (MP) can be increased when the engine (ENG) is running at its minimum speed (Vemin), such as idle speed. Therefore, even if the electric oil pump (EP) is stopped, the required flow of working oil can be supplied solely by the mechanical oil pump (MP). Furthermore, the specified increase speed is set considering the discharge performance of both the mechanical oil pump (MP) and the electric oil pump (EP).

[0087] After setting the minimum engine speed (Vemin) of the engine (ENG) to increase in step S14, the process proceeds to step S13 to execute automatic downshift control. Furthermore, in this case, since the electric oil pump EP is not driven, only the mechanical oil pump MP supplies the required flow rate (demand flow rate).

[0088] Next, refer to Figure 6 The idling stop control is explained.

[0089] In step S21, it is determined that the idle speed stop condition is met. Specifically, the controller 2 determines whether the above-mentioned idle speed stop control execution condition is met.

[0090] If the idling stop condition is determined to be met in step S21, then proceed to step S22; if the idling stop condition is determined to be not met in step S21, then proceed to end (END).

[0091] 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 to execute idle speed stop control. Conversely, if the abnormality flag is ON, the process ends.

[0092] If the engine ENG is stopped while the electric oil pump EP cannot supply working oil, the working oil required by the various components of the transmission TM cannot be supplied. Therefore, in this embodiment, if the abnormality flag is determined to be ON, i.e., the operating state of the electric oil pump EP is within the abnormal region S, idle stop control is not performed. Thus, even when the vehicle 100 is stopped, the working oil required by the oil pressure control circuit 1 can be supplied.

[0093] Next, refer to Figure 7 This section explains the control of coasting and stopping.

[0094] In step S31, it is determined whether the coasting stop condition is met. Specifically, the controller 2 determines whether the above-mentioned coasting stop control execution condition is met.

[0095] If the coasting stop condition is determined to be met in step S31, then proceed to step S32; if the coasting stop condition is determined to be not met in step S31, then proceed to end (END).

[0096] In step S32, it is determined whether the fault flag is ON or OFF. If the fault flag is OFF, the process proceeds to step S33 to execute coasting stop control. Conversely, if the fault flag is ON, the process ends.

[0097] If the engine ENG is stopped when working oil cannot be discharged from the electric oil pump EP, the necessary working oil cannot be supplied. Therefore, in this embodiment, if the abnormality flag is determined to be ON, meaning the electric oil pump EP is in the abnormal region S, coasting stop control is not performed. Thus, even when the vehicle 100 is coasting, the working oil required by the hydraulic control circuit 1 can be supplied. Therefore, actions such as returning to a lower gear can be reliably performed.

[0098] The structure, function, and effects of the embodiments of the present invention as described above are summarized and explained.

[0099] (1), (4), (7) The vehicle 100 is equipped with a transmission TM, which has: a mechanical oil pump MP (first oil pump) driven by the rotation of an engine ENG (drive source) that drives the drive wheels DW; and an electric oil pump EP (second oil pump) driven by an electric motor M. When the drive current value Im of the electric motor M becomes higher than the maximum value Imax of the drive current value Im of the electric motor M when the electric motor M is driven under normal driving conditions, the controller 2 (control device) controlling the vehicle 100, when performing automatic downshift control to automatically downshift the gear ratio of the transmission TM, will increase the minimum speed Vemin of the engine ENG (drive source) compared to the case where the drive current value Im of the electric motor M is at its maximum value Imax. Furthermore, when the main pressure PL generated by the oil pressure supplied from the mechanical oil pump MP (first oil pump) and the electric oil pump EP (second oil pump) is higher than the specified value PL1, the controller 2 (control device) controlling the vehicle 100 will not increase the minimum speed Vemin of the drive source (engine ENG) even when the drive current value Im of the electric motor M becomes higher than the maximum value Imax when the electric motor M is driven under normal driving conditions.

[0100] When the main pressure PL is higher than the specified value PL1, even if the electric oil pump EP (second oil pump) is driven, working oil cannot be supplied from the electric oil pump EP. In this case, it is simply that the electric oil pump EP cannot be driven, not that a malfunction has occurred. Therefore, when the main pressure PL is higher than the specified value PL1, no abnormality diagnosis of the electric oil pump EP is performed. This prevents unnecessary judgments that the electric oil pump EP is malfunctioning. As a result, false judgments related to the determination of abnormality of the electric oil pump EP can be suppressed, thus preventing the deterioration of fuel efficiency.

[0101] Furthermore, in the event of a malfunction of the electric oil pump EP, the minimum engine speed (Vemin) of the engine ENG is increased by a specified amount during automatic downshift control. This increases the minimum supply flow of the mechanical oil pump MP when the engine ENG is running at its minimum speed (Vemin), such as idle speed. Therefore, even if the electric oil pump EP is stopped, the required flow of working oil can be supplied solely by the mechanical oil pump MP. Thus, even in the event of an malfunction of the electric oil pump EP, downshift delays can be suppressed, and the transmission TM can be appropriately controlled.

[0102] (2), (5), (8) The vehicle 100 is equipped with a transmission TM, which has: a mechanical oil pump MP (first oil pump) driven by the rotation of an engine ENG (drive source) that drives the drive wheels DW; and an electric oil pump EP (second oil pump) driven by an electric motor M. The vehicle 100 controller 2 (control device) does not perform idle stop control to automatically stop the engine ENG (drive source) when the drive current value Im of the electric motor M becomes higher than the maximum value Imax of the drive current value Im of the electric motor M when the electric motor M is driven in the normal driving state when the electric motor M is driven by the electric motor EP (second oil pump). However, when the main pressure PL generated by the oil pressure supplied from the mechanical oil pump MP (first oil pump) and the electric oil pump EP (second oil pump) is higher than the specified value PL1, idle stop control is performed even when the drive current value Im of the electric motor M is higher than the maximum value Imax when the electric motor M is driven by the electric motor EP (second oil pump).

[0103] When the main pressure PL is higher than the specified value PL1, even if the electric oil pump EP (second oil pump) is driven, working oil cannot be supplied from the electric oil pump EP. In this case, it is simply that the electric oil pump EP cannot be driven, not that a malfunction has occurred. Therefore, when the main pressure PL is higher than the specified value PL1, no abnormality diagnosis is performed on the electric oil pump EP. This prevents unnecessarily diagnosing the electric oil pump EP as malfunctioning. Therefore, false diagnoses related to the determination of abnormality in the electric oil pump EP can be suppressed, thus preventing the deterioration of fuel efficiency.

[0104] Furthermore, in the event of a malfunction in the electric oil pump EP, idle stop control is not performed. Therefore, when the vehicle comes to a complete stop, the required flow of working oil can be supplied via the mechanical oil pump MP. Thus, even in the event of a malfunction in the electric oil pump EP, the transmission TM can be appropriately controlled.

[0105] (3), (6), (9) The vehicle 100 is equipped with a transmission TM, which has: a mechanical oil pump MP (first oil pump) driven by the rotation of an engine ENG (drive source) that drives the drive wheels DW; and an electric oil pump EP (second oil pump) driven by an electric motor M. The vehicle 100 controller 2 (control device) does not perform coasting stop control, which automatically stops the engine ENG (drive source) and cuts off the power transmission between the engine ENG (drive source) and the drive wheels DW, when the drive current value Im of the electric motor M when driving the electric oil pump EP (second oil pump) is higher than the maximum value Imax of the drive current value Im of the electric motor M when driving the electric oil pump EP (second oil pump) under normal driving conditions. When the main pressure PL generated by the oil pressure supplied from the mechanical oil pump MP (first oil pump) and the electric oil pump EP (second oil pump) is higher than the specified value PL1, coasting stop control is performed even when the drive current value Im of the electric motor M becomes higher than the maximum value Imax when driving the electric oil pump EP (second oil pump).

[0106] When the main pressure PL is higher than the specified value PL1, even if the electric oil pump EP (second oil pump) is driven, working oil cannot be supplied from the electric oil pump EP. In this case, it is simply that the electric oil pump EP cannot be driven, not that a malfunction has occurred. Therefore, when the main pressure PL is higher than the specified value PL1, no abnormality diagnosis is performed on the electric oil pump EP. This prevents unnecessarily diagnosing the electric oil pump EP as malfunctioning. Therefore, false diagnoses related to the determination of abnormality in the electric oil pump EP can be suppressed, thus preventing the deterioration of fuel efficiency.

[0107] Furthermore, in the event of a malfunction in the electric hydraulic pump EP, coasting stop control is not performed. Therefore, when the vehicle comes to a complete stop, the required flow of working fluid can be supplied via the mechanical hydraulic pump MP. Thus, even in the event of a malfunction in the electric hydraulic pump EP, the transmission TM can be appropriately controlled.

[0108] The embodiments of the present invention have been described above, but the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is not limited to the specific structure of the above embodiments.

[0109] The engine ENG can also be a diesel engine.

[0110] In the above embodiments, an example was described using a vehicle capable of performing all of the following: automatic downshift control, rapid downshift control, idle stop control, and coasting stop control. However, it is sufficient to implement any one of them.

[0111] In addition, the transmission™ is not limited to continuously variable transmissions (CVTs) but can also be a stepped transmission (TVT).

[0112] Symbol Explanation

[0113] 100: Vehicles

[0114] 1: Hydraulic control circuit

[0115] 2. Controller (Control Device)

[0116] ENG: Engine (drive source)

[0117] DW: Drive wheel

[0118] M: Electric motor

[0119] TM: Transmission

[0120] MP: Mechanical oil pump (first oil pump)

[0121] EP: Electric oil pump (second oil pump).

Claims

1. A vehicle control device for controlling a vehicle equipped with a transmission, the transmission comprising: a first oil pump driven by rotation of a drive source that drives drive wheels; and a second oil pump driven by an electric motor, wherein... When the drive current of the electric motor becomes higher than the maximum value of the drive current of the electric motor when driving the second oil pump under normal driving conditions, during automatic downshift control that automatically downshifts the transmission, the minimum speed of the drive source is increased compared to the case where the drive current of the electric motor is below the maximum value. When the main pressure generated by the oil pressure supplied from the first oil pump and the second oil pump is higher than the specified value, the minimum speed of the drive source will not increase when the automatic downshift control is executed, even if the drive current value of the motor becomes higher than the maximum value when the second oil pump is driven.

2. A method for controlling a vehicle, comprising controlling a vehicle equipped with a transmission, the transmission having: a first oil pump driven by rotation of a drive source that drives drive wheels; and a second oil pump driven by an electric motor, wherein... When the drive current of the electric motor becomes higher than the maximum value of the drive current of the electric motor when driving the second oil pump under normal driving conditions, during automatic downshift control that automatically downshifts the transmission, the minimum speed of the drive source is increased compared to the case where the drive current of the electric motor is below the maximum value. When the main pressure generated by the oil pressure supplied from the first oil pump and the second oil pump is higher than the specified value, the minimum speed of the drive source will not increase when the automatic downshift control is executed, even if the drive current value of the motor becomes higher than the maximum value when the second oil pump is driven.

3. A storage medium storing a program, said program being a computer-executable program for controlling a vehicle equipped with a transmission, said transmission comprising: a first oil pump driven by rotation of a drive source that drives drive wheels; and a second oil pump driven by an electric motor. in, The program causes the computer to perform the following steps: When the drive current of the electric motor becomes higher than the maximum value of the drive current of the electric motor when driving the second oil pump under normal driving conditions, during automatic downshift control that automatically downshifts the transmission, the minimum speed of the drive source is increased compared to the case where the drive current of the electric motor is below the maximum value. When the main pressure generated by the oil pressure supplied from the first oil pump and the second oil pump is higher than the specified value, the minimum speed of the drive source will not increase when the automatic downshift control is executed, even if the drive current value of the motor becomes higher than the maximum value when the second oil pump is driven.

Images