Vehicle control device

Abstract

To provide a vehicle controller capable of inhibiting the vehicle with an engine and an electric motor from passing through an area where engine noise increases when starting the engine.SOLUTION: If it is determined that an operating point De of an engine 12 in an increasing transitional period of engine torque Te enters an NV area where engine noise exceeds an allowable range when starting the engine, since a torque rate RT (rate of change) of the engine torque Te in the increasing transitional period of the engine torque Te is restricted, an increase in the engine torque Te in the increasing transitional period of the engine torque Te is suppressed and the operating point De of the engine 12 can be inhibited from entering the NV area. As a result, the engine noise can be inhibited from increasing.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle having an engine and an electric motor as power sources.

Background Art

[0002] Vehicles having an engine and an electric motor as power sources are well known. For example, the hybrid vehicle of Patent Document 1 is such a vehicle. Patent Document 1 describes that when the gear stage at the time of starting the engine uses a one-way clutch as an engaging element, the increase in the output of the electric motor at the time of starting the engine is larger than when the gear stage does not use a one-way clutch as an engaging element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when starting the engine and switching to engine running from motor running with the electric motor as the power source, when the rotational speed of the engine synchronizes with the synchronous rotational speed, while increasing the engine torque of the engine, torque switching is performed to decrease the torque of the electric motor. At this time, for example, when the rotational speed of the engine is in the high rotation region, depending on the engine torque during the torque increase transient period of the engine torque, there is a risk that the engine noise will increase because the operating point of the engine enters a region where the engine noise becomes large.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device for a vehicle that can suppress an increase in engine noise when starting the engine in a vehicle equipped with an engine and an electric motor.

Means for Solving the Problems

[0006] No. 1 The gist of the invention is as follows: (a) a vehicle comprising an engine, an electric motor, and a clutch for connecting and disconnecting a power transmission path between the engine and the electric motor, and when starting the engine during motor driving in which only the electric motor is used as a driving power source in a state where the clutch is disengaged, while controlling the clutch toward an engaged state, raising the rotation of the engine with the torque of the electric motor, and when the rotational speed of the engine reaches a synchronous rotational speed, increasing the engine torque of the engine and decreasing the torque of the electric motor, a control device; (b) when starting the engine, when it is determined that the operating point of the engine in the increasing transient period of the engine torque enters a predetermined region where the engine noise becomes larger than a predetermined allowable range, comprising a torque change rate limiting unit that limits the change rate of the engine torque in the increasing transient period of the engine torque 1. The torque change rate limiting unit is configured to reduce the change rate of the engine torque as the rotational speed of the engine increases. and. The gist of the second invention is as follows: (a) A vehicle comprising an engine, an electric motor, and a clutch configured to connect and disconnect a power transmission path between the engine and the electric motor, and starting the engine when running only the electric motor as a driving power source with the clutch released, pulling up the rotation of the engine with the torque of the electric motor while controlling the clutch toward an engaged state, and increasing the engine torque of the engine and decreasing the torque of the electric motor when the rotational speed of the engine reaches a synchronous rotational speed, and a control device thereof; (b) When it is determined that the operating point of the engine during the increasing transient period of the engine torque enters a predetermined region where the engine noise becomes larger than a preset allowable range at engine start, the torque change rate limiting unit configured to limit the change rate of the engine torque during the increasing transient period of the engine torque; (d) The torque change rate limiting unit is configured to increase the change rate of the engine torque as the target torque decreases when the target torque of the engine is equal to or less than a first predetermined value preset.

Advantages of the Invention

[0007] No. 1 According to the invention, when starting the engine, when it is determined that the operating point of the engine in the increasing transient period of the engine torque enters a predetermined region where the engine noise exceeds the allowable range, since the change rate of the engine torque in the increasing transient period of the engine torque is limited, the increase in the engine torque in the increasing transient period of the engine torque can be suppressed, and it is possible to suppress the operating point of the engine from entering the predetermined region. As a result, it is possible to suppress the engine noise from becoming large. Furthermore, as the rotational speed of the engine increases, the change rate of the engine torque is reduced, so that it is possible to appropriately avoid the operating point of the engine from entering the NV region. According to the second invention, when starting the engine, if it is determined that the operating point of the engine during the increasing transient period of the engine torque enters a predetermined region where the engine noise exceeds the allowable range, the change rate of the engine torque during the increasing transient period of the engine torque is limited, so that the increase in the engine torque during the increasing transient period of the engine torque is suppressed, and it is possible to prevent the operating point of the engine from entering the predetermined region. As a result, it is possible to suppress an increase in engine noise. Furthermore, when the target torque of the engine is equal to or less than a first predetermined value preset, the change rate of the engine torque is increased as the target torque decreases, so that acceleration responsiveness is ensured within a range where no shock occurs during the torque increase transient period.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0010] Fig. 1 is a diagram illustrating the schematic configuration of a vehicle 10 to which the present invention is applied, and also illustrates the main parts of the control functions and control systems for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which function as a power source for traveling. The vehicle 10 also includes a power transmission device 16 provided in a power transmission path between the engine 12 and drive wheels 14.

[0011] The engine 12 is a well-known internal combustion engine. The engine torque Te of the engine 12 is controlled by an engine control device 50, which includes a throttle actuator, a fuel injection device, and an ignition device, provided in the vehicle 10.

[0012] The electric motor MG is a rotary electric machine having a function as a motor that generates mechanical power from electric power and a function as a generator that generates electric power from mechanical power, and is a so-called motor generator. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The torque of the electric motor MG, i.e., the MG torque Tm, is controlled by controlling the inverter 52 by an electronic control unit 90. The electric power is also electric energy when not particularly distinguished. The power is also drive force, torque, and force when not particularly distinguished.

[0013] The power transmission device 16 includes a disconnection and connection clutch K0, a starting clutch WSC, an automatic transmission 20, a reduction gear mechanism 22, a differential gear 24, etc. inside a case 18. The disconnection and connection clutch K0 is a clutch that disconnects and connects between the engine 12 and the electric motor MG in the power transmission path between the engine 12 and the drive wheels 14. The starting clutch WSC is a clutch provided between the engine 12 and the electric motor MG and the automatic transmission 20 in the power transmission path between the engine 12 and the drive wheels 14. The reduction gear mechanism 22 is connected to a transmission output gear 26 of the automatic transmission 20. The differential gear 24 is connected to the reduction gear mechanism 22.

[0014] The power transmission device 16 includes a pair of drive shafts 28 connected to the differential gear 24, an engine connection shaft 30 connecting the engine 12 and the disconnection and connection clutch K0, an electric motor connection shaft 32 connecting the disconnection and connection clutch K0 and the starting clutch WSC, a mechanical oil pump 34, a transmission member 36 connecting the electric motor connection shaft 32 and the mechanical oil pump 34, etc. The transmission member 36 is composed of, for example, a sprocket and a chain.

[0015] The electric motor MG is disposed inside the case 18 and is connected to the electric motor connection shaft 32. The electric motor MG is connected to the drive wheels 14 via the starting clutch WSC or the like so as to be capable of transmitting power.

[0016] The disconnect clutch K0 is a wet friction engagement device composed of, for example, a multi-plate or single-plate clutch pressed by an actuator. The disconnect clutch K0 has its torque capacity K0 torque Tk0 changed by the regulated hydraulic pressure K0 hydraulic pressure PRk0 supplied from the hydraulic control circuit 56 provided in the vehicle 10, thereby switching the operating states, i.e., control states, such as the engaged state, slip state, and released state. The disconnect clutch K0 is a disconnect clutch between the engine 12 and the motor MG. Note that the disconnect clutch K0 corresponds to the clutch of the present invention.

[0017] The starting clutch WSC is a wet friction engagement device composed of, for example, a multi-plate or single-plate clutch pressed by an actuator. The starting clutch WSC has its torque capacity WSC torque Twsc changed by the regulated hydraulic pressure WSC hydraulic pressure PRwsc supplied from the hydraulic control circuit 56, thereby switching the control states such as the engaged state, slip state, and released state.

[0018] In the engaged state, the starting clutch WSC is configured to be able to transmit the power of the engine 12 and the power of the motor MG to the automatic transmission 20. On the other hand, in the released state of the starting clutch WSC, the power transmission from the engine 12 and the motor MG to the automatic transmission 20 is blocked.

[0019] The automatic transmission 20 is a known planetary gear type automatic transmission including, for example, one set or a plurality of sets of planetary gear devices (not shown) and an engagement device CB. The engagement device CB includes, for example, a plurality of known hydraulic friction engagement devices. Each of the engagement devices CB has its torque capacity CB torque Tcb changed by the regulated hydraulic pressure CB hydraulic pressure PRcb supplied from the hydraulic control circuit at 56, thereby switching the control states such as the engaged state, slip state, and released state.

[0020] The automatic transmission 20 is a stepped transmission in which any one of the engaging devices in the engaging device CB is engaged to form any one of a plurality of gear stages (also referred to as gear ratios) with different gear ratios (also referred to as gear ratios) γat (= AT input rotational speed Ni / AT output rotational speed No). The AT input rotational speed Ni is the rotational speed of the transmission input shaft 38. The AT output rotational speed No is the rotational speed of the transmission output gear 26.

[0021] In the power transmission device 16, the power output from the engine 12 is transmitted to the drive wheels 14 via the automatic transmission 20 and the like when both the disconnect clutch K0 and the start clutch WSC are engaged. Also, in the power transmission device 16, the power output from the electric motor MG is transmitted to the drive wheels 14 via the automatic transmission 20 and the like when the start clutch WSC is engaged.

[0022] The vehicle 10 includes a mechanical oil pump 34 connected to the electric motor connecting shaft 32 via a transmission member 36, and an electric oil pump 58 driven by a pump motor 60. The hydraulic oil OIL discharged from the mechanical oil pump 34 and the electric oil pump 58 is supplied to the hydraulic control circuit 56. The hydraulic control circuit 56 supplies the pressure-regulated K0 hydraulic pressure PRk0, WSC hydraulic pressure PRwsc, CB hydraulic pressure PRcb, etc. based on the hydraulic oil OIL discharged from the mechanical oil pump 34 and the electric oil pump 58.

[0023] The vehicle 10 further includes an electronic control device 90 as a controller including the control device of the vehicle 10. The electronic control device 90 is configured to include each computer for engine control, electric motor control, hydraulic control, etc. as required.

[0024] The electronic control unit 90 is supplied with various signals etc. (e.g., engine rotational speed Ne, MG rotational speed Nm of the electric motor MG, AT input rotational speed Ni, AT output rotational speed No corresponding to the vehicle speed V, accelerator opening θacc, throttle valve opening θth, brake-on signal Bon, brake operation amount Bra, battery temperature THbat, battery charge / discharge current Ibat, battery voltage Vbat of the battery 54, operating oil temperature THoil in the hydraulic control circuit 56, etc.) based on the detection values by various sensors etc. (e.g., engine rotational speed sensor 70, MG rotational speed sensor 72, input rotational speed sensor 74, output rotational speed sensor 76, accelerator opening sensor 78, throttle valve opening sensor 80, brake sensor 82, battery sensor 84, oil temperature sensor 86, etc.) provided in the vehicle 10.

[0025] The electronic control unit 90 outputs various command signals etc. (e.g., engine control command signal Se for engine control, MG control command signal Sm for electric motor control, CB hydraulic pressure control command signal Scb for the engagement device CB, K0 hydraulic pressure control command signal Sk0 for the disengagement clutch K0, WSC hydraulic pressure control command signal Swsc for the start clutch WSC, oil pump control command signal Seop for the electric oil pump 58, etc.) to various devices etc. (e.g., engine control unit 50, inverter 52, hydraulic control circuit 56, pump motor 60, etc.) provided in the vehicle 10.

[0026] The electronic control unit 90 includes a power source control means, i.e., a power source control section 92, and a clutch control means, i.e., a clutch control section 94, in order to realize various controls in the vehicle 10.

[0027] The power source control section 92 includes a function of controlling the operation of the engine 12 and a function of controlling the operation of the electric motor MG, and executes hybrid drive control etc. by the engine 12 and the electric motor MG by these control functions.

[0028] The power source control unit 92 calculates the driving demand amount for the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand amount map. The driving demand amount map is a relationship for obtaining the driving demand amount, which is experimentally or designedly obtained and stored in advance. The driving demand amount is, for example, the required driving torque Trdem [Nm] at the driving wheels 14. The power source control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into account transmission losses, accessory loads, the gear ratio γat of the automatic transmission 20, etc.

[0029] When the power source control unit 92 can cover the required driving torque Trdem only with the output of the electric motor MG, the driving mode for running the vehicle 10 is set to the BEV driving mode. The BEV driving mode is a motor driving mode (= BEV driving) in which the vehicle can run using only the electric motor MG as the power source in the released state of the disconnect clutch K0. On the other hand, when the power source control unit 92 cannot cover the required driving torque Trdem without using at least the output of the engine 12, the driving mode is set to the engine driving mode, that is, the HEV driving mode. The HEV driving mode is a hybrid driving mode (= HEV driving) in which the vehicle can run using at least the engine 12 as the power source in the engaged state of the disconnect clutch K0.

[0030] The power source control unit 92 determines whether there is an engine start request to switch the control state of the engine 12 from the stopped state to the operating state. For example, the power source control unit 92 determines whether there is an engine start request based on, for example, whether the required driving torque Trdem has increased beyond the range that can be covered only by the output of the electric motor MG during the BEV driving mode (i.e., during motor driving).

[0031] When the power source control unit 92 determines that there is an engine start request, the clutch control unit 94 controls the engagement / disengagement clutch K0 to execute the start control of the engine 12. For example, the clutch control unit 94 outputs a K0 hydraulic pressure control command signal Sk0 to control the disengaged engagement / disengagement clutch K0 toward the engaged state so as to obtain a K0 torque Tk0 for transmitting the cranking torque Tcr to the engine 12 side. The cranking torque Tcr is a predetermined torque required for cranking the engine 12 to increase the engine rotational speed Ne.

[0032] When the power source control unit 92 determines that there is an engine start request, it controls the engine 12 and the motor MG to execute the start control of the engine 12. For example, the power source control unit 92 outputs an MG control command signal Sm for the motor MG to output the cranking torque Tcr in accordance with the switching of the engagement / disengagement clutch K0 by the clutch control unit 94 to the engaged state. Further, the power source control unit 92 outputs an engine control command signal Se for starting fuel supply, engine ignition, etc. in conjunction with the cranking of the engine 12.

[0033] When the vehicle 10 is in BEV running, the power source control unit 92 executes the start control of the engine 12 in the slip state of the starting clutch WSC. That is, the clutch control unit 94 controls the starting clutch WSC to the slip state when starting the engine during BEV running of the vehicle 10. Thereby, it is possible to suppress the shock due to torque fluctuation accompanying the start control of the engine 12.

[0034] The clutch control unit 94 performs a shift determination of the automatic transmission 20 using, for example, a shift map which is a predetermined relationship, and outputs a CB hydraulic pressure control command signal Scb for switching the gear stage of the automatic transmission 20 as necessary.

[0035] The control during engine startup will be described in further detail below. When the engine rotational speed Ne is in the rising transient period during engine startup, the power source control unit 92 determines whether the engine rotational speed Ne has reached the MG rotational speed Nm corresponding to the synchronous rotational speed. For example, the power source control unit 92 calculates the rotational speed difference ΔN (=|Nm - Ne|) between the engine rotational speed Ne and the MG rotational speed Nm of the motor MG at any time. When the rotational speed difference ΔN becomes equal to or less than a preset synchronous determination threshold α, it is determined that the engine rotational speed Ne has reached the synchronous rotational speed (i.e., the MG rotational speed), that is, the engine rotational speed Ne has achieved rotational synchronization with the MG rotational speed Nm. Next, the power source control unit 92 executes a torque shift to increase the engine torque Te of the engine 12 while decreasing the MG torque Tm of the motor MG.

[0036] Here, during the increasing transient period of the engine torque Te (hereinafter referred to as the torque increasing transient period), if the operating point De of the engine 12 enters a predetermined region (hereinafter referred to as the NV region) where there is a risk of deterioration of engine noise and engine vibration, the engine noise and engine vibration generated during the increase of the engine torque Te will increase, which may give the driver a sense of discomfort. Also, when the operating point De of the engine 12 enters the NV region and then, for example, an upshift of the automatic transmission 20 is executed, the engine rotational speed Ne decreases and the operating point De of the engine 12 exits the NV region, there is also a risk of giving the driver a sense of discomfort as if the engine rotational speed Ne has surged. The NV region is obtained experimentally or design-wise in advance and is a region where the engine noise and engine vibration become larger than a preset allowable range. The NV region is defined, for example, by a two-dimensional map composed of the engine rotational speed Ne and the engine torque Te. Note that the NV region corresponds to the predetermined region of the present invention.

[0037] On the other hand, when it is determined that the operating point De of the engine 12 enters the NV region during the torque increase transient period at engine startup, the electronic control unit 90 functionally includes a torque change rate limiting unit 98 as torque change rate limiting means for limiting the engine torque rate RT (hereinafter referred to as torque rate RT), which is the change rate of the engine torque Te during the torque increase transient period. The torque change rate limiting unit 98 is configured to be able to change the torque rate RT according to the engine speed Ne and the target engine torque Teff (the target torque of the present invention).

[0038] First, when increasing the engine torque Te after synchronization of the engine speed Ne, the torque change rate limiting unit 98 determines whether or not the operating point De of the engine 12 enters the NV region during the torque increase transient period. For example, the torque change rate limiting unit 98 calculates a base engine torque rate RTbs (hereinafter referred to as base rate RTbs) from the target engine torque Teff, and further calculates a base engine torque command value Tebs (hereinafter referred to as base command value Tebs) during the torque increase transient period based on the base rate RTbs. The target engine torque Teff is the final target value of the engine torque Te obtained from the accelerator opening θacc, vehicle speed V, etc. The base rate RTbs is a torque rate RT that prioritizes acceleration responsiveness and is obtained from the target engine torque Teff, etc. The base command value Tebs is a command value of the engine torque Te set based on the base rate RTbs, etc. When the operating point De of the engine 12 during the torque increase transient period, which is obtained from the base command value Tebs of the engine torque Te and the engine speed Ne, enters the NV region, the torque change rate limiting unit 98 determines that the operating point De of the engine 12 enters the NV region during the torque increase transient period.

[0039] When the operating point De of the engine 12 during the torque increase transient period does not enter the NV region, the torque change rate limiting unit 98 does not limit the torque rate RT. At this time, the torque rate RT is set to, for example, the base rate RTbs.

[0040] On the other hand, when the torque change rate limiting unit 98 determines that the operating point De of the engine 12 enters the NV region during the torque increase transient period, it limits the torque rate RT of the engine torque Te. The torque rate RT applied at this time is obtained experimentally or design-wise in advance and is set to a value that prevents the operating point of the engine 12 from entering the NV region during the torque increase transient period and suppresses the acceleration failure of the vehicle 10.

[0041] The torque rate RT during restriction is changed according to, for example, the engine rotational speed Ne and the target engine torque Teff. FIG. 2 is a diagram showing the relationship between the engine rotational speed Ne and the torque rate RT. Note that the engine rotational speed Ne in FIG. 2 can be read as the MG rotational speed Nm. In FIG. 2, the solid line and the single-chain line indicate the torque rate RT during restriction, and the broken line indicates the torque rate RT when not restricted. When the torque rate RT is not restricted, the torque rate RT is set to the base rate RTbs indicated by the broken line, for example. On the other hand, when the torque rate RT is restricted, as shown by the solid line and the single-chain line, when the engine rotational speed Ne becomes equal to or higher than a predetermined rotational speed N1, the torque rate RT decreases as the engine rotational speed Ne increases. As the engine rotational speed Ne increases to a higher speed, the operating point De of the engine 12 approaches the NV region. Therefore, by decreasing the restricted torque rate RT as the engine rotational speed Ne increases, the operating point De of the engine 12 is appropriately prevented from entering the NV region.

[0042] FIG. 3 is a diagram showing the relationship between the target engine torque Teff and the torque rate RT. In FIG. 3, the broken line corresponds to the upper limit value RTmax of the torque rate RT defined in advance. The torque rate RT indicated by the solid line and the single-dashed line is changed according to the target engine torque Teff. As shown by the solid line and the dashed-dotted line, in the region where the target engine torque Teff is equal to or less than the first predetermined value Te1 defined in advance, the torque rate RT increases as the target engine torque Teff decreases. Also, in the region where the target engine torque Teff is higher than the first predetermined value Te1, the torque rate RT is limited to a low value. Further, when the target engine torque Teff is equal to or higher than the second predetermined value Te2 defined in advance and higher than the first predetermined value Te1, the torque rate RT increases as the target engine torque Teff increases.

[0043] The region where the target engine torque Teff is equal to or less than the first predetermined value Te1, which is low torque, is a region where there is no risk that the operating point De of the engine 12 enters the NV region during the torque increase transient period. Therefore, in the region where the target engine torque Teff is equal to or less than the first predetermined value Te1, the torque rate RT is increased as the target engine torque Teff decreases so as to ensure the acceleration responsiveness within a range where no shock occurs during the torque increase transient period.

[0044] When the target engine torque Teff is between the first predetermined value Te1 and the second predetermined value Te2, there is a risk that the operating point De of the engine 12 enters the NV region during the torque increase transient period. On the other hand, the torque rate RT is limited to a low value so as to avoid the operating point De of the engine 12 from entering the NV region.

[0045] In the region where the target engine torque Teff is equal to or higher than the second predetermined value Te2, the driver's acceleration request is high. If the torque rate RT is restricted too much in this region, there is a risk that the acceleration responsiveness of the vehicle 10 will deteriorate and the driver will feel uncomfortable. In such a case, the acceleration responsiveness is gradually prioritized according to the target engine torque Teff, and the increase in the torque rate RT as the target engine torque Teff increases can suppress the deterioration of the acceleration responsiveness.

[0046] Based on the relationships shown in FIGS. 2 and 3, the torque change rate limiting unit 98 determines the torque rate RT during limiting. For example, the torque change rate limiting unit 98 decreases the torque rate RT as the engine rotational speed Ne increases. In a region where the target engine torque Teff is less than or equal to the first predetermined value Te1, the torque rate RT is increased as the target engine torque Teff decreases. In a region where the target engine torque Teff is greater than or equal to the second predetermined value Te2, the torque rate RT is increased as the target engine torque Teff increases.

[0047] When the torque rate RT is determined, the power source control unit 92 calculates an engine torque command value Tetgt (hereinafter referred to as the torque command value Tetgt), which is a command value for the engine torque Te, based on the torque rate RT, and outputs an engine control command signal Se for controlling the engine torque Te with the calculated torque command value Tetgt as the target.

[0048] On the other hand, when the torque rate RT is restricted, the engine torque Te becomes insufficient, making it difficult to achieve the required driving torque Trdem. Therefore, while the torque rate RT is restricted, the power source control unit 92 outputs an MG control command signal Sm for increasing the MG torque Tm of the electric motor MG. Specifically, the power source control unit 92 increases the MG torque Tm of the electric motor MG by the amount of decrease in the engine torque Te (or the torque command value Tetgt) caused by the restriction of the torque rate RT. As a result, the decrease in acceleration responsiveness is suppressed because the shortage of the engine torque Te caused by the restriction of the torque rate RT is compensated for by the MG torque Tm.

[0049] FIG. 4 is a time chart for explaining the control state at engine startup. In FIG. 4, the horizontal axis represents time t [sec], and the vertical axis represents, in order from the top, each rotational speed (engine rotational speed Ne, MG rotational speed Nm, AT input rotational speed Ni), the engine torque command value Tetgt [Nm], and each torque (engine torque Te, MG torque Tm).

[0050] When engine starting is initiated at time t1 in FIG. 4, the MG torque Tm required to increase the engine rotational speed Ne increases. Also, although not shown, by controlling the disengagement / engagement clutch K0 toward the engaged state, after time t1, the MG torque Tm is transmitted to the engine side via the disengagement / engagement clutch K0, and thus the engine rotational speed Ne increases. At time t2, when the rotational speed difference ΔN (=|Nm - Ne|) between the MG rotational speed Nm and the engine rotational speed Ne becomes equal to or less than the synchronization determination threshold value α, the rotational synchronization of the engine rotational speed Ne is determined. After time t2, the torque switching between the engine torque Te and the MG torque Tm is started.

[0051] At time t2, after the torque command value Tetgt is increased to the initial value Tes set in advance, the torque command value Tetgt corresponding to the torque rate RT is set as needed. The torque command value Tetgt1 indicated by the solid line in FIG. 4 is the torque command value Tetgt when set based on the base rate RTbs. That is, the torque command value Tetgt1 is the torque command value Tetgt when not considering the NV region. In this case, since it enters the NV region during the torque increase transient period, the engine noise and engine vibration increase.

[0052] The torque command value Tetgt2 indicated by the broken line in FIG. 4 is the torque command value Tetgt when the torque rate RT is limited so that the operating point De of the engine 12 does not enter the NV region. At this time, by limiting the torque rate RT, the torque command value Tetgt2 rises gently, and as a result, the operating point De of the engine 12 is prevented from entering the NV region. At time t3 in FIG. 4, for example, when the automatic transmission 20 is upshifted, the decrease in the engine rotational speed Ne starts. In relation to this, the threshold value of the engine torque Te at which the operating point De of the engine 12 becomes the NV region is increased. Accordingly, the torque rate RT gradually increases from time t3, and the gradient of the torque command value Tetgt2 also increases. At time t4, the torque command value Tetgt2 reaches the target engine torque Teff, and the torque switching is completed.

[0053] Figure 5 is another time chart for explaining the control state at engine startup. The time chart in Figure 5 shows a case where the target engine torque Teff is low and the operating point De of engine 12 does not enter the NV region during the engine startup transient period.

[0054] The dashed line in Figure 5 indicates the torque command value Tetgt1 when the target engine torque Teff is the first target value Teff1. At this time, when the torque command value Tetgt1 is set based on the base rate RTbs, the operating point De of engine 12 enters the NV region during the torque increase transient period. On the other hand, the solid line in Figure 5 indicates the torque command value Tetgt2 when the target engine torque Teff is the second target value Teff2. Since the second target value Teff2 is a low value, even when the torque command value Tetgt2 is set based on the base rate RTbs, the operating point De of engine 12 does not enter the NV region. In such a case, the torque rate RT can be increased. Note that Figure 5 corresponds to the mode when the target engine torque Teff is in the region below the first predetermined value Te1 in Figure 3.

[0055] Figure 6 is a flowchart for explaining the main part of the control operation of the electronic control device 90 and is a flowchart for explaining the control operation that can prevent the operating point De of engine 12 from entering the NV region at engine startup. This flowchart is repeatedly executed during engine startup. In Figure 6, step (hereinafter, steps are omitted) S10 corresponds to the control function of the power source control unit 92, and S20 to S40 correspond to the control function of the torque change rate limiting unit 98.

[0056] In S10 of FIG. 6, at engine start, it is determined whether or not torque is being switched, while increasing engine torque Te and decreasing MG torque Tm of the motor MG. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, in S20, it is determined whether or not the operating point of the engine 12 enters the NV region during the transient period of increasing the engine torque Te. If the determination in S20 is negative, in S40, the final torque rate RT is set to, for example, the base rate RTbs. On the other hand, if the determination in S20 is positive, in S30, the torque rate RT at the time of restriction is obtained based on the engine rotational speed Ne, the target engine torque Teff, etc., and this torque rate RT is set as the final torque rate RT. In this way, when it is determined that the operating point De of the engine 12 enters the NV region, by restricting the torque rate RT, it is possible to prevent the operating point De from entering the NV region at engine start.

[0057] As described above, according to this embodiment, at engine start, when it is determined that the operating point De of the engine 12 during the increasing transient period of the engine torque Te enters the NV region where the engine noise exceeds the allowable range, since the torque rate RT (change rate) of the engine torque Te during the increasing transient period of the engine torque Te is restricted, the increase in the engine torque Te during the increasing transient period of the engine torque Te is suppressed, and it is possible to suppress the operating point De of the engine 12 from entering the NV region. As a result, it is possible to suppress an increase in engine noise. Furthermore, since the shortage of the engine torque Te caused by the restriction of the torque rate RT is compensated by the MG torque Tm, a decrease in the acceleration response is suppressed.

[0058] As described above, the embodiments of the present invention have been described in detail based on the drawings, but the present invention is also applicable in other aspects.

[0059] For example, in the above-described embodiment, the launch clutch WSC was provided between the engine 12, the motor MG, and the automatic transmission 20, but the launch clutch WSC may be substituted for any of the engaging devices CB of the automatic transmission 20. Further, when a torque converter having a lock-up clutch is interposed between the engine 12, the motor MG, and the automatic transmission 20, the lock-up clutch may be substituted for the launch clutch WSC.

[0060] Also, in the above-described embodiment, the torque rate RT was changed during the torque increase transient period, but furthermore, the initial value Tes of the engine torque Te may also be changed.

[0061] Note that the above is merely one embodiment, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

Explanation of Reference Numerals

[0062] 10: Vehicle 12: Engine 90: Electronic control unit 98: Torque change rate limiting unit MG: Motor K0: Disconnect clutch (clutch)

Claims

1. an engine, an electric motor, and a clutch that connects and disconnects a power transmission path between the engine and the electric motor; A control device for a vehicle, when starting the engine during motor running in which the vehicle runs using only the electric motor as a power source for running with the clutch released, controls the clutch toward an engaged state while increasing the rotation speed of the engine by the torque of the electric motor, and when the rotation speed of the engine reaches a synchronous rotation speed, increases the engine torque of the engine and decreases the torque of the electric motor, a torque change rate limiting unit that, when it is determined that an operating point of the engine during an engine torque increase transition period falls within a predetermined region where engine noise becomes larger than a predetermined allowable range at engine start, limits a change rate of the engine torque during the engine torque increase transition period; The torque change rate limiting unit reduces the change rate of the engine torque as the rotation speed of the engine increases. A vehicle control device characterized by:

2. The torque change rate limiting unit increases the rate of change of the engine torque as the target torque of the engine decreases when the target torque of the engine is equal to or less than a first predetermined value.

2. The vehicle control device according to claim 1.

3. An engine, an electric motor, and a clutch that disconnects a power transmission path between the engine and the electric motor, A control device for a vehicle, when starting the engine during motor running in which the vehicle runs using only the electric motor as a power source for running with the clutch released, controls the clutch toward an engaged state while increasing the rotation speed of the engine by the torque of the electric motor, and when the rotation speed of the engine reaches a synchronous rotation speed, increases the engine torque of the engine and decreases the torque of the electric motor, a torque change rate limiting unit that, when it is determined that an operating point of the engine during an engine torque increase transition period falls within a predetermined region where engine noise becomes larger than a predetermined allowable range at engine start, limits a change rate of the engine torque during the engine torque increase transition period; When the target torque of the engine is equal to or less than a first predetermined value that is predefined, the torque change rate limiting unit increases the change rate of the engine torque as the target torque decreases. A vehicle control device characterized by the above.

4. When the target torque of the engine is equal to or higher than a second predetermined value that is predefined and higher than the first predetermined value, the torque change rate limiting unit increases the change rate of the engine torque as the target torque increases. The vehicle control device according to claim 3, characterized by the above.

5. While the change rate of the engine torque is limited, it is configured to increase the torque of the electric motor. The vehicle control device according to claim 1, characterized by the above.

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