control device

Abstract

To balance restriction of discomfort of an operator and restriction where input power of a power storage device greatly exceeds input limit in a manual range.SOLUTION: A controller is given in which: engine fuel is cut when an accelerator is turned off, or an engine, a first motor and a second motor are controlled to realize request braking-torque in accompany with operation and motoring of the engine through the first motor. When the accelerator is turned off and when a shift range is changed to a manual range through a shift selecting unit during limitation of fuel cut of the engine, the request braking-torque is reduced without using rate processing regardless of input limit of a power storage device. When the manual range is selected by the shift selecting unit and when the limitation of fuel cut of the engine is started, the request braking-torque is reduced using rate processing regardless of input limit of the power storage device.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, this type of control device has been proposed as a control device installed in a vehicle having an engine with a filter attached to the exhaust system that captures particulate matter.When the temperature of the filter is above a threshold value, a temperature rise limiting control is used to limit fuel cut-off in the engine in order to prevent the filter from overheating (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-125720 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle in which a first motor, an engine, drive wheels, and a second motor are connected to the sun gear, carrier, and ring gear of a planetary gearbox, and a power storage device is connected to the power line along with the first and second motors, and a manual range can be selected to approximate the behavior of an engine installed in a vehicle equipped with an engine and a transmission, limiting engine fuel cutoff when the accelerator is released reduces engine friction and reduces the so-called engine brake torque generated by motoring the engine by the first motor. In this case, increasing the engine speed is considered to achieve the required braking torque of the vehicle. However, in the manual range, the driver desires a shifting feel similar to that of an engine vehicle equipped with an engine and a transmission. Therefore, if the increase in engine speed differs from the shifting feel expected by the driver, it can cause the driver to feel uncomfortable. To alleviate this discomfort, it is considered to increase the regenerative torque of the second motor. However, increasing the regenerative torque of the second motor may significantly exceed the input limit of the power storage device.

[0005] The control device of the present disclosure has a primary object to achieve both suppression of the sense of discomfort felt by the driver and suppression of the input power of the power storage device from significantly exceeding the input limit in the manual range. [Means for solving the problem]

[0006] The control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The control device of the present disclosure is mounted on a vehicle including an engine, a first motor, a second motor, a planetary gear having three rotating elements respectively connected to the first motor, the engine, and the second motor, an electricity storage device capable of exchanging electric power with the first and second motors, and a shift selection device that selects one shift range from a plurality of shift ranges including a manual range that brings the behavior of the engine closer to the behavior of an engine mounted on a vehicle having an engine and a transmission, and when the accelerator is released, performs demand control with fuel cut or operation of the engine and motoring of the engine by the first motor. The gist of the present invention is a control device that controls the engine and the first and second motors so as to realize a dynamic torque, and when the accelerator is released and the shift range is changed to the manual range by the shift selection device while fuel cut restriction on the engine is in progress, the control device reduces the required braking torque without using rate processing regardless of the input restriction on the power storage device, and when fuel cut restriction on the engine is initiated while the manual range is selected by the shift selection device, the control device reduces the required braking torque using rate processing regardless of the input restriction on the power storage device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle 20. [Figure 2] 10 is a flowchart illustrating an example of a processing routine. [Figure 3] FIG. 10 is an explanatory diagram showing an example of a state when the accelerator is released in an HV driving mode. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic diagram of a hybrid vehicle 20 equipped with a control device according to the embodiment. As shown in the figure, the hybrid vehicle 20 includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 28, a planetary gear 30, motors MG1 and MG2 (first and second motors), inverters 41 and 42, a battery (power storage device) 50, a transmission 60, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70. The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel. An exhaust system of the engine 22 is equipped with a purification device 25 that purifies unburned fuel and nitrogen oxides in the exhaust of the engine 22, and a PM filter 26 that collects particulate matter (PM) such as soot in the exhaust. The operation of the engine 22 is controlled by the engine ECU 28. The engine ECU 28 has a microcomputer that receives signals from various sensors, outputs various control signals, performs various calculations, and communicates with the HVECU 70. For example, the engine ECU 28 receives inputs such as the crank angle θcr of the crankshaft 23 of the engine 22 from the crank position sensor 23a, the intake air amount Qa of the engine 22 from the air flow meter, and the differential pressure ΔPf before and after (upstream and downstream) the PM filter 26 from the differential pressure sensor 26a. The engine ECU 28 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr, and calculates the load factor KL of the engine 22 (the ratio of the volume of air actually taken in per cycle to the stroke volume per cycle of the engine 22) based on the intake air amount Qa and the rotation speed Ne. The engine ECU 28 calculates the PM accumulation amount Qpm (the amount of particulate matter accumulated on the PM filter 26) based on the differential pressure ΔPf, and calculates the filter temperature Tf (the temperature of the PM filter 26) based on the rotation speed Ne and the load factor KL. The planetary gear 30 is configured as a single-pinion planetary gear mechanism, with the rotor of the motor MG1 connected to the sun gear, the crankshaft 23 of the engine 22 connected to the carrier, and the ring gear connected to an intermediate shaft 35. The rotor of the motor MG2 is attached to the intermediate shaft 35.The motors MG1 and MG2 are configured as, for example, synchronous generator motors, and are rotationally driven by the HVECU 70 controlling the switching of multiple switching elements of the inverters 41 and 42. The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the power line 54 together with the inverters 41 and 42. The battery 50 is managed by the HVECU 52. The transmission 60 is configured as a stepped transmission, for example, with four, five, or six speeds. The input shaft of the transmission 60 is connected to the intermediate shaft 35, and the output shaft is connected to the drive shaft 36, which is coupled to the drive wheels 39a and 39b via a differential gear 38. The transmission 60 is controlled by the HVECU 70. The HVECU 70 has a microcomputer that receives signals from various sensors, outputs various control signals, performs various calculations, and communicates with the engine ECU 28. For example, the inputs include rotational positions θm1, θm2 of the rotors of motors MG1, MG2 from rotational position sensors 43, 44, and voltage Vb, current Ib, and temperature Tb of battery 50 from voltage sensor 51a, current sensor 51b, and temperature sensor 51c. Other inputs include a start signal from start switch 80, a shift position (operation position and shift range of shift lever (shift selection device)) SP from shift position sensor 82, accelerator opening (amount of accelerator pedal depression) Acc from accelerator pedal position sensor 84, brake pedal position (amount of brake pedal depression) BP from brake pedal position sensor 86, and vehicle speed V from vehicle speed sensor 87. Control signals are output to inverters 41, 42, transmission 60, etc. Based on the rotational positions θm1, θm2, rotational speeds Nm1, Nm2 of motors MG1, MG2 are calculated. The power Pb of the battery 50 is calculated as the product of the voltage Vb and the current Ib, the storage rate SOC of the battery 50 is calculated based on the integrated value of the current Ib, and the input / output limits (allowable input / output power) Win, Wout of the battery 50 are calculated based on the storage rate SOC and the temperature Tb.The shift position SP is available in various positions, including a parking range (P range), a reverse range (R range), a neutral range (N range), a forward range (D range), and a manual range (M range). The manual range (M range) is also provided with an upshift range (+ range) and a downshift range (- range). In the M range, the engine 22 and the motors MG1 and MG2 are controlled and driven so that the behavior of the engine 22 approaches the behavior of an engine installed in an automobile equipped with an engine and a stepped transmission.

[0010] In the hybrid vehicle 20, the engine 22, motors MG1, MG2, and transmission 60 are controlled by cooperative control between the engine ECU 28 and the HVECU 70 so that the vehicle travels in an electric travel mode (EV travel mode) in which the engine 22 is stopped, or in a hybrid travel mode (HV travel mode) in which the engine 22 is running. The transmission 60 is controlled so that the gear Gs becomes a target gear Gs* based on the accelerator opening Acc and the vehicle speed V when the shift position SP is in the D range, and is controlled so that the gear Gs becomes a target gear Gs* based on the shift position SP when the shift position SP is in the M range. The engine 22 and motors MG1, MG2 are controlled so that the required torque Ti* of the intermediate shaft 35 is output to the intermediate shaft 35 with the engine 22 running or stopped. The required torque Ti* is obtained by dividing the required torque Td* of the drive shaft 36, which is based on the accelerator pedal position Acc and the vehicle speed V, by the rotation speed ratio Gt corresponding to the gear position Gs of the transmission 60. In particular, when the accelerator is released in HV driving mode, the engine 22 and motors MG1, MG2 are controlled so that the required braking torque Ti2* of the intermediate shaft 35 is output to the intermediate shaft 35 by the so-called engine brake torque that acts on the intermediate shaft 35 due to fuel cut or operation of the engine 22 and motoring of the engine 22 by the motor MG1, and the regenerative torque of the motor MG2. The required braking torque Ti2* is obtained by dividing the required braking torque Td2* of the drive shaft 36 by the rotation speed ratio Gt of the transmission 60. The required braking torque Td2* is set to the above-mentioned required torque Td* (torque on the braking side, hereinafter referred to as "basic braking torque Td2a") when the accelerator pedal position Acc is zero, or a torque smaller than that within the braking side range. In the following explanation of when the accelerator is released, for ease of explanation, with the exception of Figure 3, the absolute values ​​of the braking side torque of the drive shaft 36 and the intermediate shaft 35 (required braking torque Td2*, Ti2*, engine brake torque, regenerative torque of the motor MG2) and the input side power of the battery 50 (power Pb and input limit Win) will be omitted (assumed to be positive).The motor MG1 is controlled so that the engine 22 rotates at a target rotation speed Ne*, and the motor MG2 is controlled so that a torque equal to the difference between the required braking torque Ti2* and an engine braking torque estimated, for example, based on the torque of the motor MG1 is output. At this time, the battery 50 is charged and discharged based on the electric power of the motors MG1 and MG2. The engine 22 performs a fuel cut when the filter temperature Tf is less than a threshold value Tfref that is slightly lower than the overheat temperature of the PM filter 26. As a result, air (oxygen) is supplied to the PM filter 26, causing particulate matter deposited on the PM filter 26 to burn and regenerate the PM filter 26. When the filter temperature Tf is equal to or higher than the threshold value Tfref, the engine 22 operates with a limited fuel cut and a relatively small amount of fuel (for example, the lower limit amount that can be combusted) injected to prevent the PM filter 26 from overheating. In this case, compared to when fuel is cut, the friction of the engine 22 is reduced, resulting in a smaller engine brake torque. This increases the regenerative torque of the motor MG2 to achieve the required braking torque Td2* (required braking torque Ti2*), and the electric power Pb of the battery 50 increases toward charging. When the shift position SP is in the D range, the target rotation speed Ne* is set to the basic rotation speed Nea when the electric power Pb of the battery 50 has a margin above the input limit Win. When the electric power Pb reaches the input limit Win, the target rotation speed Ne* is increased within a range below the allowable upper limit rotation speed Nemax relative to the basic rotation speed Nea. For example, the rotation speed Ne immediately before the accelerator is released is used as the basic rotation speed Nea. The target rotation speed Ne* is increased to accommodate the decrease in electric power Pb due to the increase in electric power consumption of the motor MG1 and the decrease in regenerative power of the motor MG2. The increase in the target rotation speed Ne* is set so that the electric power Pb has a margin above the input limit Win. When the shift position SP is in the M range, the target rotation speed Ne* is set using the vehicle speed V, the target gear Gs* of the transmission 60, and a target rotation speed setting map. In the target rotation speed setting map, the target rotation speed Ne* is set so that it increases linearly as the vehicle speed V increases at each gear, and so that the slope with respect to the vehicle speed V decreases as the gear Gs increases.As a result, when the engine 22 is operated at the target rotation speed Ne*, the rotation speed Ne of the engine 22 increases as the vehicle speed V increases at each gear of the transmission 60, the rotation speed Ne of the engine 22 decreases when the gear Gs is upshifted, and the rotation speed Ne of the engine 22 increases when the gear Gs is downshifted. By setting the target rotation speed Ne* of the engine 22 in this manner, the behavior of the rotation speed Ne of the engine 22 is made closer to the behavior of an engine mounted on an automobile equipped with an engine and a stepped transmission.

[0011] Next, the operation of the hybrid vehicle 20, particularly the process for setting the required braking torque Td2* when the accelerator is released in the HV driving mode, will be described. Figure 2 is a flowchart showing an example of a processing routine executed by the HVECU 70. This routine is repeatedly executed when the accelerator is released in the HV driving mode.

[0012] When the routine of FIG. 2 is executed, the HVECU 70 first determines whether the shift position SP is in the M range (step S100). If the shift position SP is not in the M range, the routine is terminated. If the shift position SP is in the M range, the HVECU 70 determines whether fuel cut of the engine 22 is to be restricted (step S110). Step S110 is performed, for example, by checking the value of a fuel cut restriction flag. The fuel cut restriction flag is set to a value of 0 or a value of 1 by the engine ECU 28 when fuel cut of the engine 22 is to be performed or restricted, respectively, and the flag is transmitted to the HVECU 70. If fuel cut of the engine 22 is not to be restricted in step S110, the routine is terminated. If fuel cut of the engine 22 is to be restricted in step S110, a reduction determination is made to reduce the required braking torque Td2* (step S120). At this time, the HVECU 70 transmits a notification to the engine ECU 28, which then displays the notification on the display 29. Next, it is determined whether the shift position SP was in the M range the previous time this routine was executed (step S130). Since the current range is the M range in step S100, if the range is not the M range in step S130, it means that the shift position SP has just been switched to the M range from a range other than the M range, and if the range is the M range in step S130, it means that the shift position SP continues to be in the M range.

[0013] If the vehicle is not in the M range in step S130, a first reduction process for the required braking torque Td2* is performed (step S140), and the routine ends. In the first reduction process, the required braking torque Td2* is reduced from the basic braking torque Td2a by a reduction amount without using rate processing, regardless of the input limit Win of the battery 50. When the reduction of the required braking torque Td2* is completed, the reduction completion flag is set to ON. The reduction amount for the required braking torque Td2* is set based on the vehicle speed V, etc. By reducing the required braking torque Td2* (required braking torque Ti2*), the regenerative torque of the motor MG2 is prevented from increasing, and the electric power Pb of the battery 50 is prevented from significantly exceeding the input limit Win. Because the required braking torque Td2* (required braking torque Ti2*) is reduced without using rate processing, the torque output to the drive shaft 36 may suddenly change, causing a shock. Now, immediately after the shift position SP is switched to the M range, the driver anticipates a certain degree of shock, and so the sense of discomfort felt by the driver is suppressed. This makes it possible to simultaneously suppress the sense of discomfort felt by the driver and prevent the power Pb of the battery 50 from greatly exceeding the input limit Win.

[0014] If the range is M in step S130, a second reduction process for the required braking torque Td2* is performed (step S150), and the routine ends. In the second reduction process, regardless of the input limit Win of the battery 50, after waiting a predetermined time (e.g., several seconds) from the reduction determination, the reduction request flag is turned on and the required braking torque Td2* is gradually reduced over time from the basic braking torque Td2a using rate processing. When the reduction of the required braking torque Td2* is completed, the reduction completion flag is turned on. Here, the reason for waiting a predetermined time from the reduction determination and gradually reducing the required braking torque Td2* over time using rate processing from the basic braking torque Td2a is that even if the engine 22 is controlled to limit fuel cut, it takes time for the fuel cut limit to actually begin due to a response delay of the engine 22. The reduction amount of the required braking torque Td2* is set in the same manner as in the first reduction process. By reducing the required braking torque Td2* (required braking torque Ti2*), the regenerative torque of the motor MG2 is prevented from increasing, and the electric power Pb of the battery 50 is prevented from significantly exceeding the input limit Win. Because the shift position SP remains in the M range, the driver does not anticipate a shock. Therefore, if a sudden change in the torque output to the drive shaft 36 causes a shock, the driver will feel uncomfortable. In this embodiment, by gradually reducing the required braking torque Td2* from the basic braking torque Td2a over time using rate processing, the occurrence of such a shock can be suppressed, and the driver's discomfort can be reduced. This makes it possible to both suppress the driver's discomfort and prevent the electric power Pb of the battery 50 from significantly exceeding the input limit Win.

[0015] FIG. 3 is an explanatory diagram showing an example of a state when the accelerator is released in HV driving mode. In FIG. 3(a), when the shift position SP is switched from D range to M range (time t0) while fuel cutoff of the engine 22 is restricted, a determination is made to reduce the required braking torque Td2*, a notification to that effect is displayed on the display 29, and a first reduction process for the required braking torque Td2* is initiated. In the first reduction process, a reduction request flag is turned on to reduce the required braking torque Td2* without performing rate processing, and a reduction completion flag is turned on. In FIG. 3(b), when fuel cutoff of the engine 22 is restricted while the shift position SP is maintained in M ​​range (time t1), a determination is made to reduce the required braking torque Td2*, and a second reduction process for the required braking torque Td2* is initiated. In the second reduction process, after waiting for a predetermined time from the reduction decision (time t2), the reduction request flag is turned on and the required braking torque Td2* is gradually reduced by rate processing, and when the reduction of the required braking torque Td2* is completed (time t3), the reduction completion flag is turned on.

[0016] According to the control device of the embodiment described above, when the accelerator is released and the shift position SP is changed to M range while the fuel cut of the engine 22 is being restricted, a first reduction process is executed, and when the M range is selected as the shift position SP and the restriction on the fuel cut of the engine 22 is initiated, a second reduction process is executed, thereby suppressing the discomfort felt by the driver and suppressing the power Pb of the battery 50 from significantly exceeding the input limit Win.

[0017] In the control device of the embodiment, the transmission 60 may be a continuously variable transmission. Furthermore, the control device of the embodiment may be applied to a hybrid vehicle that does not include the transmission 60 and virtually approximates the behavior of the engine 22 to the behavior of an engine in a vehicle that includes an engine and a transmission.

[0018] The present disclosure is not limited to the above-described embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the spirit of the present disclosure. [Explanation of symbols]

[0019] 20 Hybrid Vehicles, 28 Engine ECUs, 70 HVECUs.

Claims

[Claim 1] a transmission connected to a drive shaft having an input shaft connected to the intermediate shaft and an output shaft connected to drive wheels; an electricity storage device capable of exchanging electric power with the first and second motors; and a shift selection device that selects one of a plurality of shift ranges including a manual range that brings the behavior of the engine closer to the behavior of an engine mounted in a vehicle equipped with the engine and the transmission, the control device being mounted on a vehicle that includes an engine, a first motor, and a second motor connected to an intermediate shaft; When the accelerator is released and the shift range is changed to the manual range by the shift selection device during the restriction of fuel cut of the engine, the required braking torque is reduced without using rate processing regardless of the input restriction of the power storage device, and when the restriction of fuel cut of the engine is started while the manual range is selected by the shift selection device, the required braking torque is reduced using the rate processing regardless of the input restriction of the power storage device. Control device.

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