Control device for vehicle

Abstract

To provide a control device for a vehicle which can reduce shock when travel is started due to backlash in a driving system and can reduce consumption power required to take up the backlash of the driving system.SOLUTION: HCU measures total travel distance of a vehicle and sets backlash take-up torque for taking up backlash of a driving system from a motor to a driving wheel on the basis of the total travel distance (step S2) and outputs the set backlash take-up torque to the motor when the vehicle stops (step S3). The HCU sets so that the backlash take-up torque becomes smaller as the total travel distance becomes larger.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Patent document 1 describes a technology in which the motor outputs the minimum amount of backlash-reducing torque required to eliminate backlash in the drive system from the motor to the wheels for a limited time from the time it is detected that the driving range has been selected while the creep cut permission condition is met. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-250648 Summary of the Invention [Problem to be solved by the invention]

[0004] The torque required to eliminate backlash in the drivetrain varies depending on the total mileage of the vehicle. For example, a vehicle with a short total mileage requires a relatively large torque to eliminate backlash because the gears are not grounded, whereas a vehicle with a long total mileage requires a smaller torque to eliminate backlash because the gears are grounded.

[0005] However, in the technology described in Patent Document 1, because the backlash-reducing torque generated by the electric motor is a constant fixed value, if a small backlash-reducing torque is set for a vehicle whose total mileage is equal to or greater than a certain distance, there is a problem that backlash-reducing shock due to creep torque is tolerated in vehicles whose total mileage is short.On the other hand, if a large backlash-reducing torque is set for a vehicle whose total mileage is short, there is a problem that more power than necessary is consumed each time the backlash-reducing torque is output in vehicles whose total mileage is equal to or greater than a certain distance.

[0006] Therefore, an object of the present invention is to provide a vehicle control device that can reduce the shock at the start of driving caused by backlash in the drive system and can reduce the power consumption required to eliminate backlash in the drive system. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a vehicle control device that is mounted on a vehicle equipped with a motor for driving and includes a control unit that controls the motor, wherein the control unit measures the total distance traveled by the vehicle, sets a clearance-reducing torque for reducing clearance in the drive system from the motor to the drive wheels based on the total distance traveled, and outputs the set clearance-reducing torque to the motor when the vehicle is stopped. [Effects of the Invention]

[0008] In this way, according to the present invention, it is possible to provide a vehicle control device that can reduce the shock at the start of driving caused by backlash in the drive system and reduce the power consumption required to eliminate backlash in the drive system. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a vehicle control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing the procedure for setting and outputting the backlash-eliminating torque by the vehicle control device according to one embodiment of the present invention. [Figure 3] FIG. 3 is a flowchart showing the details of the operation of setting the backlash eliminating torque by the vehicle control device according to one embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the relationship between the total travel distance and the torque required to eliminate backlash in the vehicle control device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] A vehicle control device according to one embodiment of the present invention is mounted on a vehicle equipped with a driving motor and includes a control unit that controls the motor, wherein the control unit measures a total travel distance of the vehicle, sets a backlash-reducing torque for reducing backlash in the drive train from the motor to the drive wheels based on the total travel distance, and causes the motor to output the set backlash-reducing torque when the vehicle is stopped. As a result, the vehicle control device according to one embodiment of the present invention can reduce shock caused by backlash in the drive train when starting to drive and can reduce power consumption required to reduce backlash in the drive train. [Example]

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle equipped with a vehicle control device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0012] As shown in FIG. 1, a vehicle 1 according to one embodiment of the present invention includes an engine 2, an automatic transmission 3, a driving motor 4, drive wheels 5, an HCU (Hybrid Control Unit) 10 as a control unit that comprehensively controls the vehicle 1, an ECM (Engine Control Module) 11 that controls the engine 2, a TCM (Transmission Control Module) 12 that controls the automatic transmission 3, an ISGCM (Integrated Starter Generator Control Module) 13, an INVCM (Inverter Control Module) 14, and a BMS (Battery Management System) 16.

[0013] The engine 2 is formed with a plurality of cylinders. In this embodiment, the engine 2 is configured to perform a series of four strokes for each cylinder, including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

[0014] An ISG (Integrated Starter Generator) 20 and a starter 21 are connected to the engine 2. The ISG 20 is connected to a crankshaft 18 of the engine 2 via a belt 22 or the like. The ISG 20 functions as an electric motor that rotates when supplied with electric power, thereby driving the engine 2 to rotate, and also functions as a generator that converts the rotational force input from the crankshaft 18 into electric power.

[0015] In this embodiment, the ISG 20 functions as an electric motor under the control of the ISGCM 13, thereby restarting the engine 2 from a stopped state caused by the idling stop function. The ISG 20 can also assist the vehicle 1 in traveling by functioning as an electric motor.

[0016] The starter 21 includes a motor and a pinion gear (not shown). The starter 21 rotates the motor to rotate the crankshaft 18, thereby providing the rotational force for starting the engine 2. In this manner, the engine 2 is started by the starter 21 and is restarted by the ISG 20 from a stopped state due to the idling stop function.

[0017] The automatic transmission 3 changes the speed of the rotation output from the engine 2 and drives the drive wheels 5 via a drive shaft 23. The automatic transmission 3 includes a constantly meshing stepped transmission mechanism 25 made up of a parallel shaft gear mechanism, a clutch 26 made up of a dry clutch, a differential mechanism 27, and an actuator (not shown). The clutch 26 is provided between the engine 2 and the transmission mechanism 25. The transmission mechanism 25 changes the speed of the rotation transmitted from the engine 2 via the clutch 26 and outputs it to the drive wheels 5.

[0018] The automatic transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and an actuator controlled by the TCM 12 switches gears in the transmission mechanism 25 and engages (connects) and disengages (disconnects) the clutch 26. In this embodiment, the clutch 26 of the automatic transmission 3 is a normally stop type clutch that maintains its current state (degree of engagement) when the actuator is not operating or when the actuator cannot operate due to a malfunction. The differential mechanism 27 transmits the power output by the transmission mechanism 25 to the drive shaft 23.

[0019] The motor 4 is connected to the differential mechanism 27 via a chain 28. The motor 4 outputs power between the transmission mechanism 25 and the drive wheels 5. The motor 4 functions as an electric motor and a generator.

[0020] In this way, vehicle 1 forms a parallel hybrid system that can use the power of both engine 2 and motor 4 for driving, and is a hybrid vehicle that runs on the power output by at least one of engine 2 and motor 4.

[0021] The vehicle 1 is capable of HEV running and EV running. HEV running is a running state in which the engine 2 is operated and the vehicle runs using at least the engine torque of the engine 2. HEV running includes a state in which the vehicle runs using only the engine torque, or both the engine torque and the motor torque of the motor 4. This HEV running also includes a mode in which the vehicle 1 starts using only the motor torque and then runs using both the motor torque and the engine torque. EV running is a running state in which the operation of the engine 2 is stopped and the vehicle runs using the motor torque.

[0022] The motor 4 generates electricity by running the vehicle 1. The motor 4 need only be connected to any point in the power transmission path from the engine 2 to the drive wheels 5 so as to be capable of transmitting power, and does not necessarily have to be connected to the differential mechanism 27.

[0023] The vehicle 1 includes a first power storage device 30, a high-voltage power pack 34 including a second power storage device 33 as a power storage unit, a high-voltage cable 35, and a low-voltage cable 36.

[0024] The first power storage device 30 and the second power storage device 33 are configured by rechargeable secondary batteries. The first power storage device 30 is configured by a lead battery.

[0025] The first power storage device 30 is a low-voltage battery in which the number of cells and other factors are set so as to generate an output voltage of approximately 12 V. The state of the first power storage device 30, such as the remaining capacity, temperature, and charge / discharge current, is managed by the HCU 10.

[0026] The second power storage device 33 is a high-voltage battery in which the number of cells and the like are set so as to generate a higher voltage than the first power storage device 30, and generates an output voltage of, for example, 100 V. The second power storage device 33 is formed, for example, of a lithium-ion battery. The state of the second power storage device 33, such as the amount of stored power, temperature, and charge / discharge current, is managed by the BMS 16.

[0027] The vehicle 1 is provided with a general load 37 as an electrical load. The general load 37 is an electrical load other than the starter 21 and the ISG 20.

[0028] The general loads 37 are electrical loads that do not require a stable power supply and are used temporarily. The general loads 37 include, for example, windshield wipers (not shown) and an electric cooling fan that blows cooling air to the engine 2.

[0029] The first power storage device 30 is connected via a low-voltage cable 36 to the starter 21, the ISG 20, and a general load 37 as an electrical load so as to be able to supply electric power thereto.

[0030] In this way, the first power storage device 30 is configured to supply at least electric power to the starter 21 and the ISG 20, which serve as starters for starting the engine 2.

[0031] The high-voltage power pack 34 has an inverter 45, an INVCM 14, and a BMS 16 in addition to the second power storage device 33. The high-voltage power pack 34 is connected to the motor 4 via a high-voltage cable 35 so as to be able to supply electric power to the motor 4.

[0032] Under the control of INVCM 14, inverter 45 converts AC power applied to high-voltage cable 35 into DC power applied to second power storage device 33, and vice versa. For example, when INVCM 14 powers motor 4, INVCM 14 converts DC power discharged from second power storage device 33 into AC power using inverter 45 and supplies the AC power to motor 4.

[0033] When the motor 4 is in a regenerative mode, the INVCM 14 converts AC power generated by the motor 4 into DC power using the inverter 45, and charges the second power storage device 33 with the DC power.

[0034] HCU10, ECM11, TCM12, ISGCM13, INVCM14 and BMS16 are each composed of a computer unit equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, etc., input ports and output ports.

[0035] The ROMs of these computer units store various constants, various maps, and the like, as well as programs for causing the computer units to function as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, and BMS 16, respectively.

[0036] That is, the CPU executes the programs stored in the ROM using the RAM as a work area, and these computer units function as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, and BMS 16 in this embodiment, respectively.

[0037] The vehicle 1 is provided with CAN (Controller Area Network) communication lines 48 and 49 for forming an in-vehicle LAN (Local Area Network) that conforms to standards such as CAN.

[0038] The HCU 10 is connected to the INVCM 14 and the BMS 16 by a CAN communication line 48. The HCU 10, the INVCM 14, and the BMS 16 mutually transmit and receive signals such as control signals via the CAN communication line 48.

[0039] The HCU 10 is connected to the ECM 11, the TCM 12, and the ISGCM 13 via a CAN communication line 49. The HCU 10, the ECM 11, the TCM 12, and the ISGCM 13 mutually transmit and receive signals such as control signals via the CAN communication line 49.

[0040] To the input port of the HCU 10, various sensors such as a vehicle speed sensor 51, an accelerator opening sensor 52, a shift position sensor 53, and a brake sensor 54 are connected.

[0041] The vehicle speed sensor 51 detects the speed of the vehicle 1 from the rotation speed of the drive shaft 23, etc. The accelerator opening sensor 52 detects the operation amount of an accelerator pedal (not shown) as the accelerator operation amount. The brake sensor 54 detects the operation amount (brake stroke) of a brake pedal (not shown) as the brake operation amount.

[0042] The shift position sensor 53 detects the shift position selected by the driver's operation of a shift lever (not shown). The shift position may be selected from, for example, a forward driving range (D range), a reverse driving range (R range), a parking range (N range), or a parking range (P range). Here, the D range and the R range are defined as driving ranges, and the N range and the P range are defined as non-driving ranges.

[0043] The HCU 10 controls the gear position of the transmission mechanism 25 of the automatic transmission 3 using the TCM 12 in accordance with the shift position selected by the driver. Specifically, when the shift position is in the D range, the HCU 10 switches the transmission mechanism 25 to one of the forward gear positions according to the vehicle speed, the torque required by the driver, etc., and when the shift position is in the R range, the HCU 10 switches the transmission mechanism 25 to a reverse gear position. Furthermore, when the shift position is in the N range, the HCU 10 switches the transmission mechanism 25 to neutral, and when the shift position is in the P range, the HCU 10 switches the transmission mechanism 25 to a parking state.

[0044] During HEV driving, the HCU 10 controls the engine 2 and the motor 4 so that the axle request torque required for the drive wheels 5 is satisfied by the engine torque and the motor torque. In other words, the HCU 10 sets the torque distribution so that the sum of the engine torque and the motor torque is equal to the axle request torque, and causes the engine 2 to generate the set engine torque, and causes the motor 4 to generate the set motor torque. During EV driving, the HCU 10 controls the motor 4 so that the axle request torque required for the drive wheels 5 is satisfied by the motor torque. Under normal circumstances, the HCU 10 sets the value of the driver request torque based on the driver's accelerator pedal operation amount (accelerator operation amount) as the axle request torque.

[0045] Here, because there is backlash in the drivetrain of the vehicle 1, vibrations and impact noises may occur when this backlash is eliminated when the vehicle 1 starts moving. In other words, backlash due to gear backlash or the like may occur in the power transmission path of the drivetrain from the motor 4 to the drive wheels 5. For this reason, when creep driving is resumed or during normal acceleration, the vehicle 1 starts moving only after the backlash in the drivetrain has been eliminated, which may result in abnormal noises such as gear banging or shocks.

[0046] Therefore, while the vehicle 1 is stopped, it is desirable to generate the minimum motor torque (hereinafter also referred to as backlash-reducing torque) required to eliminate backlash in the drive system in the motor 4, and eliminate backlash in the drive system in preparation for the vehicle 1 starting.

[0047] The backlash-reducing torque varies depending on the total mileage of vehicle 1. The total mileage is the distance traveled since vehicle 1 was manufactured. When the total mileage is low, the gears and other components are not grounded and friction is high, so the backlash-reducing torque is relatively large. When the total mileage is above a certain distance, the gears and other components are grounded and friction is low, so the backlash-reducing torque is relatively small. Note that "gears grounding" is also referred to as "wearing," and means that as the contact surfaces of the gears rub against each other, minute misalignments and distortions on the contact surfaces are smoothed out, reducing friction. The lower the friction, the smaller the required backlash-reducing torque.

[0048] If a small backlash-eliminating torque is set when the total mileage is above a certain distance, the backlash-eliminating torque will be insufficient when the total mileage is short, resulting in a backlash-eliminating shock caused by creep torque. On the other hand, if a large backlash-eliminating torque is set when the total mileage is short, more power than necessary will be consumed each time the backlash-eliminating torque is output when the total mileage is above a certain distance. Therefore, if the backlash-eliminating torque is set to a fixed value, it will be impossible to eliminate backlash in the drivetrain and reduce power consumption at the same time.

[0049] In this embodiment, the HCU 10 measures the total distance traveled by the vehicle 1, sets a clearance-reducing torque for eliminating clearance in the drive system from the motor 4 to the drive wheels 5 based on the total distance traveled, and outputs the set clearance-reducing torque to the motor 4 when the vehicle 1 is stopped.

[0050] Moreover, the HCU 10 sets the backlash eliminating torque so that the longer the total traveling distance is, the smaller the backlash eliminating torque becomes.

[0051] The operation of setting and outputting the backlash-eliminating torque by the vehicle control device according to this embodiment will be described with reference to Fig. 2. This operation is repeatedly executed while the system is running.

[0052] The HCU 10 determines whether the vehicle 1 is stopped (step S1). Here, if conditions such as a brake operation being performed and the vehicle speed being 0 are met, the HCU 10 determines that the vehicle 1 is stopped. If the HCU 10 determines that the vehicle 1 is not stopped (NO in step S1), it ends this operation.

[0053] When the HCU 10 determines that the vehicle 1 is stopped (YES in step S1), the HCU 10 sets a backlash eliminating torque (step S2).

[0054] Next, the HCU 10 outputs a torque for eliminating backlash (step S3), and ends this operation.

[0055] The operation of setting the backlash-eliminating torque by the vehicle control device according to this embodiment will be described with reference to Fig. 3. This operation is repeatedly executed while the system is running. This operation corresponds to step S2 in Fig. 2.

[0056] The HCU 10 determines whether the total travel distance is equal to or less than D1 (step S11).

[0057] When the HCU 10 determines that the total travel distance is equal to or less than D1 (YES in step S11), it sets the backlash eliminating torque to T1 (step S12) and ends the current operation.

[0058] When the HCU 10 determines that the total travel distance is not equal to or less than D1 (NO in step S11), the HCU 10 determines whether the total travel distance is equal to or less than D2 (step S13).

[0059] If the HCU 10 determines that the total travel distance is equal to or less than D2 (YES in step S13), it sets the backlash eliminating torque to T2 (step S14) and ends the current operation.

[0060] If the HCU 10 determines that the total travel distance is not equal to or less than D2 (NO in step S13), it sets the backlash eliminating torque to T3 (step S15) and ends the current operation.

[0061] In this way, the HCU10 sets the backlash-eliminating torque to T1 when the total travel distance is within the range of D1 or less, sets the backlash-eliminating torque to T2 when the total travel distance is greater than D1 and within the range of D2 or less, and sets the backlash-eliminating torque to T3 when the total travel distance is greater than D2.

[0062] The relationship between the total travel distance and the torque required to eliminate backlash will be described with reference to FIG.

[0063] In Figure 4, the vertical axis represents the torque required to eliminate backlash, and the horizontal axis represents the total travel distance. As shown in Figure 4, the torque required to eliminate backlash, represented by the solid line, decreases sharply as the total travel distance increases in the range where the total travel distance is short (the range below D2), and decreases gradually as the total travel distance increases in the range where the total travel distance is long (the range above D2).

[0064] When the total mileage is less than or equal to D1, the backlash-reducing torque is set to T1. T1 is the maximum torque required to eliminate backlash when the total mileage is less than or equal to D1. In other words, T1 is a sufficient value to eliminate backlash in the drivetrain when the total mileage is less than or equal to D1.

[0065] When the total travel distance is greater than D1 and less than D2, the backlash-removing torque is set to T2. T2 is the maximum torque required to remove backlash when the total travel distance is greater than D1 and less than D2. In other words, T2 is a sufficient value to remove backlash in the drivetrain when the total travel distance is greater than D1 and less than D2.

[0066] In the range where the total mileage is greater than D2, the backlash-reducing torque is set to T3. T3 is the maximum torque required to eliminate backlash in the range where the total mileage is greater than D2. In other words, T3 is a sufficient value to eliminate backlash in the drivetrain in any range where the total mileage is greater than D2.

[0067] As shown in Figure 4, the total travel distance is divided into three ranges, and a value sufficient to eliminate backlash in the drive train is set as the backlash-eliminating torque in each range. In other words, the backlash-eliminating torque value is set to three levels according to the total travel distance. This makes it possible to set the minimum motor torque necessary to eliminate backlash in the drive train as the backlash-eliminating torque.

[0068] In the example of Fig. 4, the value of the backlash-eliminating torque is set in three stages according to the total travel distance, but it may be set in more stages or continuously. For example, the total travel distance may be divided into more detailed ranges, and a backlash-eliminating torque may be set for each range. Also, the backlash-eliminating torque may be set continuously so that it becomes the same value as the torque required for backlash elimination, as indicated by the solid line.

[0069] As described above, in this embodiment, the HCU 10 measures the total travel distance of the vehicle 1, sets a clearance-reducing torque for eliminating clearance in the drive system from the motor 4 to the drive wheels 5 based on the total travel distance, and outputs the set clearance-reducing torque to the motor 4 when the vehicle 1 is stopped.

[0070] As a result, the backlash eliminating torque is set based on the total travel distance of the vehicle 1, so that the shock at the start of travel can be reduced and the power consumption required for backlash eliminating can be reduced.

[0071] In this embodiment, the HCU 10 sets the backlash eliminating torque so that the longer the total traveling distance is, the smaller the backlash eliminating torque becomes.

[0072] As a result, the longer the total travel distance of the vehicle 1, the smaller the backlash-eliminating torque is set, which reduces the shock at the start of travel and reduces the power consumption required for backlash-eliminating.

[0073] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0074] 1 vehicle 4 motors 10 HCU (control unit)

Claims

1. A vehicle control device is mounted on a vehicle having a driving motor and includes a control unit that controls the motor, The control unit Measure the total distance traveled by the vehicle; setting a torque for eliminating backlash in a drive system from the motor to the drive wheels based on the total travel distance; a control device for a vehicle that causes the motor to output the set backlash eliminating torque when the vehicle is stopped;

2. The control unit 2. The vehicle control device according to claim 1, wherein the backlash eliminating torque is set to be smaller as the total traveling distance increases.

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