JP4680365B2 - Vehicle drive control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle drive control device, and in particular, when an electric motor travels by outputting a reaction torque with respect to an output torque of the engine, it prevents a stall due to an excessive load acting on the engine. It is about technology.
[0002]
[Prior art]
(a) A gear-type composite distribution having a first rotating element connected to an engine that operates by combustion of fuel, a second rotating element connected to a motor generator, and a third rotating element that outputs to drive wheels. (B) operating the engine and the motor generator together with the first rotating element, the second rotating element, and the third rotating element being relatively rotatable, and the first rotating element and the second rotating element. 2. Description of the Related Art A vehicle drive control device that travels by applying torque to a two-rotation element and rotating a third rotation element is known. For example, the device described in Japanese Patent Laid-Open No. 9-193676 is an example, and a planetary gear device is used as a synthesizing / distributing device.
[0003]
Further, although FIG. 1 is not yet known, when a double pinion type planetary gear unit 18 is used as a synthesizing / distributing device, the engine 14 is connected to a sun gear 18s as a first rotating element, and the second rotating element The motor generator 16 is coupled to the carrier 18c, and the ring gear 18r serving as the third rotating element is coupled to the transmission 12 via the second clutch C2 and is output to the drive wheels. In the ETC mode in which the first clutch C1 and the first brake B1 are released and the second clutch C2 is engaged, for example, as shown in FIG. 5 (a), the engine 14 is operated and the sun gear 18s ( In addition to applying a positive torque to S), regenerative control is performed in a state where the motor generator 16 rotates in reverse, and a regenerative braking torque is applied to the carrier 18c (C), thereby rotating the ring gear 18r (R) in the positive direction. You can travel.
[0004]
[Problems to be solved by the invention]
However, in such a vehicle drive control device, for example, a large load is applied by overcoming obstacles or sudden braking during traveling in the ETC mode of FIG. 5 (a), and the vehicle speed and further the ring gear 18r (R). When the rotation speed of the engine decreases rapidly, the engine rotation speed (the rotation speed of the sun gear 18s (S)) decreases as shown by the broken line in FIG. 9B, the engine stalls, that is, the engine stalls and misfires, There is a possibility that torque cannot be generated. In particular, when the rotational speed control is performed so that the motor rotational speed becomes a predetermined value (minus) in order to perform regenerative control by rotating the motor generator 16 backward, the decrease in the vehicle speed is absorbed by the decrease in the engine rotational speed. The possibility of engine stall is high. Further, when the operation of the engine 14 is appropriately stopped, for example, when the motor generator 16 travels with the first clutch C1 engaged, as in the hybrid drive control device of FIG. Therefore, it is strongly desired to prevent the engine stall.
[0005]
As a cause of the engine stall, for example, in FIG. 9B, instead of the rotation speed of the ring gear 18r (R) decreasing, the regenerative braking torque of the motor generator 16 increases rapidly and the carrier 18c (C). Even if the rotational speed of the engine changes (closes to 0), the rotational speed of the sun gear 18s (S) may decrease and stall, and various forms are considered depending on the connection state of the engine and the motor generator. It is done.
[0006]
The present invention has been made against the background of the above circumstances, and its object is to prevent an engine from being overloaded and stalled when the engine and the motor are both operated. There is.
[0008]
[Means for Solving the Problems]
The first invention comprises: (a) a first rotating element connected to an engine that operates by combustion of fuel; Motor generator And a third rotating element that outputs to the driving wheel, and in the collinear diagram showing the relationship between the rotational speeds of the three rotating elements, the first rotating element and the second rotating element A gear-type synthesizing / distributing device configured such that the third rotating element is positioned between the first rotating element, the second rotating element, and the third rotating element. In state, the engine To apply engine torque to the first rotating element, Said Generating motor generator Let By that In the vehicle drive control device having the ETC mode in which the third rotating element is rotated, (c) whether or not there is a possibility that the engine rotational speed is lowered and stalled when traveling in the ETC mode. An engine stall detecting means for detecting the engine stall, and (d) when the engine stall detecting means determines that there is a possibility of a stall, Motor generator of Electric-generating capacity Engine stall prevention means for reducing the load acting on the engine by reducing the engine load.
[0009]
A second invention is the vehicle drive control device according to the first invention, wherein the engine stall prevention means Motor generator of Electric-generating capacity The time for lowering is 1 second or less.
[0012]
First 3 The invention is the first invention Or the second invention In the vehicular drive control apparatus, the engine stall detection means predicts a stall based on a change in the rotational speed of the engine.
[0013]
First 4 The invention is from the first invention to the first 3 In any one of the vehicle drive control devices according to the present invention, the drive wheel includes a second drive source that drives one of the front wheel and the rear wheel of the vehicle and the other of the front wheel and the rear wheel. Features.
[0014]
First 5 Invention 4 The vehicle drive control apparatus according to the invention is characterized in that the vehicle drive control device further comprises auxiliary drive means for increasing the drive force by the second drive source when the engine load is reduced by the engine stall prevention means.
[0015]
【The invention's effect】
In the vehicle drive control apparatus according to the first aspect of the present invention, the engine stall detecting means detects whether or not the engine is likely to stall, and if it is determined that the stall is likely, the engine stall is detected. By preventive measures Motor generator of Electric-generating capacity As a result, the load acting on the engine is reduced, the decrease in the engine speed is suppressed, or the engine speed is increased by itself, and the engine stall is prevented. In that case, Motor generator Since the control is highly responsive, engine stall can be effectively prevented.
[0017]
In the second invention, the engine stall prevention means Motor generator of Electric-generating capacity Since the time to reduce the time is 1 second or less, Motor generator of Electric-generating capacity A decrease in driving force accompanying the decrease can be suppressed in an extremely short time.
[0019]
First 3 In the invention, the engine stall detection means predicts the stall based on the change in the rotational speed of the engine, so that the possibility of the engine stall can be detected at a relatively high stage of the engine rotational speed. Can be prevented.
[0020]
First 5 In the invention, when the engine load is reduced by the engine stall prevention means, the driving force by the second drive source is increased by the auxiliary drive means, so that the reduction of the driving force accompanying the reduction of the engine load is reduced as a whole vehicle. The In addition, since the decrease in driving force is reduced in this way, it is possible to lengthen the engine load reduction time to prevent engine stall, and to ensure sufficient recovery time from engine torque drop. become.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
As the gear type synthesizing / distributing device, a double pinion type or single pinion type planetary gear device is preferably used, but a bevel gear type differential gear device can also be used. Various modes are possible for the connection form of the engine and the electric motor to the composite distributor.
[0022]
For example, when the rotation speed of the third rotation element decreases while the rotation speed of the second rotation element is substantially constant, the combining / distributing device is configured to decrease the rotation speed of the first rotation element. An engine stall may occur when the vehicle speed drops sharply due to an object or brake operation. In addition, the rotation speed of the first rotation element is decreased due to the change in the rotation speed of the second rotation element accompanying the increase in the torque of the electric motor while the rotation speed of the third rotation element is substantially constant. May cause an engine stall when the motor torque increases rapidly.
[0023]
Specifically, when the composite distribution device is a double pinion type planetary gear device, for example, (a) the engine is connected to the sun gear and the electric motor is connected to the carrier, while (b) the ring gear of the planetary gear device is connected. A first brake coupled to the case; (c) a first clutch coupling the carrier to the transmission; and (d) a second clutch coupling the ring gear to the transmission. The present invention is applied during traveling in a traveling mode in which one clutch and the first brake are released and the second clutch is engaged. In this case, the engine stall may occur when the vehicle speed drops sharply due to an obstacle or brake operation, etc., and the motor torque (regenerative braking torque for reverse rotation, power running torque for normal rotation) increases rapidly. There is also a possibility that engine stall will occur even if it increases.
[0024]
The electric motor may function only as an electric motor that is rotationally driven by electric energy, or may function only as an electric generator that generates electric power by being rotationally driven and generates braking torque, or both the electric motor and the electric generator A motor generator having the above functions may be used.
[0025]
The engine stall detection means is, for example, 3 Although it is desirable that the stall is predicted based on a change in the rotational speed of the engine as in the invention, it may be determined based on whether or not the rotational speed of the engine has fallen below a predetermined lower limit value. It is also possible to determine the possibility of engine stall from other physical quantities related to engine load such as speed. Various modes can be employed, such as determining the possibility of engine stall when the vehicle speed or the engine rotation speed becomes a predetermined value or less.
[0026]
The engine stall prevention means of the first invention is, for example, Motor generator of Electric-generating capacity Is configured to be 0, that is, rotatable, Motor generator of Electric-generating capacity Various aspects can be adopted, such as reducing the amount by a certain amount or a certain rate, or by reducing the amount by a predetermined amount according to the possibility of engine stall or the like.
[0027]
In the second invention, Motor generator of Electric-generating capacity Is 1 second or less, more preferably 500 milliseconds or less. Even when the engine load is reduced by other means, it is desirable that the reduction time be 1 second or less in order to suppress the reduction of the driving force to the necessary minimum. It should be noted that it may be determined whether engine stall has been avoided based on the engine rotational speed or its change, and engine load reduction control by the engine stall prevention means may be stopped.
[0030]
First 3 The engine stall detection means of the invention can determine whether or not the amount of change ΔNe per predetermined time of the engine rotational speed Ne is equal to or less than a predetermined value (minus), or the target engine rotational speed Ne. ^* And the difference between the actual engine speed Ne (Ne ^* -Ne) is configured to determine whether or not a predetermined value or more. If the engine speed Ne changes suddenly due to a sudden change in the driving load, etc., the deviation (Ne ^* −Ne) increases, so the deviation (Ne) ^* The case where engine stall is predicted based on whether or not -Ne) is equal to or greater than a predetermined value is also based on a change in engine speed.
[0031]
The amount of change ΔNe and deviation (Ne ^* The predetermined value (determination value) for predicting the engine stall in -Ne) may be a constant value, but the vehicle speed, the engine rotation speed, and the like can also be set as parameters.
[0032]
First 5 In the invention, it is desirable that the increase amount by which the driving force by the second driving source is increased by the auxiliary driving means is substantially equal to the decrease amount of the driving force due to the reduction of the engine load by the engine stall prevention means. It may be increased by a certain amount. Further, when the torque of the electric motor is set to 0 by the engine stall prevention means, the driving force of one of the front and rear wheels becomes 0. Therefore, all the driving forces required according to the driver's output request amount are set to the second value. It may be generated by a drive source.
[0033]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating a hybrid drive control device 10 as a vehicle drive control device according to an embodiment of the present invention. FIG. 2 is a skeleton diagram including a transmission 12, and this hybrid drive control device. 10 includes an engine 14 such as an internal combustion engine that generates power by burning fuel, a motor generator 16 that is used as an electric motor and a generator, and a double pinion type planetary gear unit 18. Engine / front drive) Used mounted horizontally on vehicles. The engine 14 is connected to the sun gear 18s of the planetary gear unit 18, the motor generator 16 is connected to the carrier 18c, and the ring gear 18r is connected to the case 20 via the first brake B1. The carrier 18c is connected to the input shaft 22 of the transmission 12 via the first clutch C1, and the ring gear 18r is connected to the input shaft 22 via the second clutch C2. The motor generator 16 corresponds to an electric motor, the planetary gear device 18 corresponds to a gear-type combining / distributing device, the sun gear 18s corresponds to a first rotating element, the carrier 18c corresponds to a second rotating element, and the ring gear 18r corresponds to a third rotating element. To do.
[0034]
The clutches C1 and C2 and the first brake B1 are wet multi-plate hydraulic friction engagement devices that are frictionally engaged by a hydraulic actuator, and are frictionally engaged by hydraulic oil supplied from the hydraulic control circuit 24. It is like that. FIG. 3 is a diagram showing a main part of the hydraulic control circuit 24. The original pressure PC generated by the electric hydraulic pressure generator 26 including the electric pump is transferred to the shift lever 30 (see FIG. 1) via the manual valve 28. Is supplied to each of the clutches C1, C2 and the brake B1 according to the shift position. The shift lever 30 is a shift operation member that is operated by the driver. In this embodiment, the shift lever 30 is selected and operated in five shift positions of “B”, “D”, “N”, “R”, and “P”. The manual valve 28 is connected to the shift lever 30 via a cable, a link, or the like, and can be mechanically switched in accordance with the operation of the shift lever 30.
[0035]
The “B” position is a shift position in which a relatively large power source brake is generated due to a downshift of the transmission 12 during forward travel, and the “D” position is a shift position for forward travel. In these shift positions, The original pressure PC is supplied from the output port 28a to the clutches C1 and C2. The original pressure PC is supplied to the first clutch C <b> 1 via the shuttle valve 31. The “N” range is a shift position that cuts off power transmission from the power source, the “R” position is a shift position that travels backward, and the “P” position cuts off power transmission from the power source and is not shown in the drawing. The shift positions mechanically prevent the drive wheels from rotating, and at these shift positions, the original pressure PC is supplied from the output port 28b to the first brake B1. The original pressure PC output from the output port 28b is also input to the return port 28c. In the “R” position, the original pressure PC is supplied from the return port 28c to the first clutch C1 via the output port 28d. It has come to be.
[0036]
The clutches C1, C2 and the brake B1 are provided with control valves 32, 34, 36, respectively, and their hydraulic pressure P _C1 , P _C2 , P _B1 Is to be controlled. Hydraulic pressure P of clutch C1 _C1 Is regulated by an ON-OFF valve 38, and the clutch C2 and the brake B1 are regulated by a linear solenoid valve 40.
[0037]
Then, according to the operating states of the clutches C1, C2 and the brake B1, the travel modes shown in FIG. 4 are established. That is, in the “B” range or the “D” range, any one of “ETC mode”, “direct connection mode”, and “motor traveling mode (forward)” is established, and in the “ETC mode”, the second clutch C2 is engaged. In a state where the first clutch C1 and the first brake B1 are released and in other words, the sun gear 18s, the carrier 18c, and the ring gear 18r are relatively rotatable, the engine 14 and the motor generator 16 are operated together to operate the sun gear 18s. Torque is applied to the carrier 18c, and the ring gear 18r is rotated to move the vehicle forward. In the “direct connection mode”, the engine 14 is operated to drive the vehicle forward while the clutches C1 and C2 are engaged and the first brake B1 is released. In the “motor running mode (forward)”, the motor generator 16 is operated to drive the vehicle forward while the first clutch C1 is engaged and the second clutch C2 and the first brake B1 are released. In the “motor running mode (forward)”, the motor generator 16 is regeneratively controlled when the accelerator is OFF, etc., so that the battery 42 (see FIG. 1) is charged by generating electricity with the kinetic energy of the vehicle and the braking force is applied to the vehicle. Can be generated.
[0038]
FIG. 5 is a collinear diagram showing the operating state of the planetary gear unit 18 in the forward mode, wherein “S” represents the sun gear 18s, “R” represents the ring gear 18r, “C” represents the carrier 18c, and so on. Is determined by the gear ratio ρ (= the number of teeth of the sun gear 18s / the number of teeth of the ring gear 18r). Specifically, when the interval between “S” and “C” is 1, the interval between “R” and “C” is ρ, and in this embodiment, ρ is about 0.6. The torque ratio in the ETC mode (a) is engine torque Te: CVT input shaft torque Tin: motor torque Tm = ρ: 1: 1−ρ, and the motor torque Tm can be smaller than the engine torque Te. In the steady state, the torque obtained by adding the motor torque Tm and the engine torque Te becomes the CVT input shaft torque Tin. CVT means a continuously variable transmission. In this embodiment, a belt type continuously variable transmission is provided as the transmission 12.
[0039]
Returning to FIG. 4, in the “N” range or the “P” range, either “neutral” or “charging / engage start mode” is established, and in the “neutral” state, the clutches C1, C2 and the first brake B1 are Both are released. In the “charging / Eng start mode”, the clutches C1 and C2 are disengaged and the first brake B1 is engaged, the motor generator 16 is rotated in the reverse direction to start the engine 14, or the engine 14 passes through the planetary gear unit 18. The motor generator 16 is rotationally driven and the motor generator 16 is regeneratively controlled to generate electric power, and the battery 42 (see FIG. 1) is charged.
[0040]
In the “R” range, “motor travel mode (reverse)” or “friction travel mode” is established. In “motor travel mode (reverse)”, the first clutch C1 is engaged and the second clutch C2 and the second clutch C2 are engaged. With the one brake B1 released, the motor generator 16 is rotationally driven in the reverse direction to reversely rotate the carrier 18c and further the input shaft 22, thereby causing the vehicle to travel backward. The “friction running mode” is executed when an assist request is issued during reverse running in the “motor running mode (reverse)”. The engine 14 is started to rotate the sun gear 18s in the forward direction, In a state where the ring gear 18r is rotated in the forward direction along with the rotation of the sun gear 18s, the first brake B1 is slip-engaged to limit the rotation of the ring gear 18r, thereby rotating the carrier 18c in the reverse direction. Assists reverse travel by applying force.
[0041]
The transmission 12 is a belt-type continuously variable transmission, and power is transmitted from its output shaft 44 through a counter gear 46 to a ring gear 50 of a differential 48, and the differential 48 provides left and right drive wheels (this embodiment). Then, the power is distributed to the front wheels 52.
[0042]
The hybrid drive control apparatus 10 of the present embodiment is configured such that the travel mode is switched by the HVECU 60 shown in FIG. The HVECU 60 includes a CPU, a RAM, a ROM, and the like, and performs signal processing in accordance with a program stored in advance in the ROM while using a temporary storage function of the RAM, whereby an electronic throttle ECU 62, an engine ECU 64, an M / GECU 66, The T / MECU 68, the ON / OFF valve 38 of the hydraulic control circuit 24, the linear solenoid valve 40, the starter 70 of the engine 14 and the like are controlled. The electronic throttle ECU 62 controls the opening and closing of the electronic throttle valve 72 of the engine 14, the engine ECU 64 controls the engine output by the fuel injection amount of the engine 14, the variable valve timing mechanism, the ignition timing, etc. The M / GECU 66 is an inverter. The T / MECU 68 controls the power running torque, regenerative braking torque, etc. of the motor generator 16 via 74, and the T / MECU 68 has a transmission gear ratio γ (= input shaft rotational speed Nin / output shaft rotational speed Nout), belt tension, etc. Is to control. The hydraulic control circuit 24 includes a circuit for controlling the speed ratio γ and belt tension of the transmission 12. The starter 70 is an electric motor, and the pinion provided on the motor shaft meshes with a ring gear provided on a flywheel or the like of the engine 14 to crank the engine 14.
[0043]
The HVECU 60 is supplied with a signal representing the operation amount θac of the accelerator pedal 78 as an accelerator operation member from the accelerator operation amount sensor 76 and a signal representing the operation position (shift position) of the shift lever 30 from the shift position sensor 80. Is supplied. Further, from the engine rotation speed sensor 82, the motor rotation speed sensor 84, the input shaft rotation speed sensor 86, and the output shaft rotation speed sensor 88, the engine rotation speed (rotation speed) Ne, the motor rotation speed (rotation speed) Nm, and the input shaft, respectively. Signals representing the rotation speed (rotation speed of the input shaft 22) Nin and the output shaft rotation speed (rotation speed of the output shaft 44) Nout are supplied. The output shaft rotational speed Nout corresponds to the vehicle speed V. In addition, various signals representing the operation state such as the storage amount SOC of the battery 42 are supplied. The storage amount SOC may be simply a battery voltage, or may be obtained by sequentially integrating the charge / discharge amount. The accelerator operation amount θac represents the driver's requested output amount.
[0044]
FIG. 6 illustrates the “ETC mode”, “direct connection mode”, and “motor travel mode (forward)” according to the driving state during forward travel when the shift lever 30 is operated to the “D” position or the “B” position. FIG. 6 is a flowchart for explaining an operation when appropriately switching between and is executed by signal processing of the HVECU 60.
[0045]
In step S1 of FIG. 6, it is determined whether or not the shift position of the shift lever 30 is “D” or “B”. If “D” or “B”, the vehicle speed V is determined in step S2 or not. Determine whether. The determination vehicle speed V1 is set to a constant value such as about 15 km / h based on output characteristics of the motor generator 16 and the engine 14, energy consumption, and the like. If V> V1, “direct connection mode” is set in step S7. When V ≦ V1, it is determined in step S3 whether or not the driver's output request amount SP is equal to or less than a determination value SP1. The requested output amount SP is obtained from an arithmetic expression or map determined in advance based on the accelerator operation amount θac, the vehicle speed V, and the like, and the determination value SP1 cannot be obtained by, for example, the motor generator 16 alone. The output ratio is set as a parameter, such as a gear ratio γ. If SP> SP1, “ETC mode” is selected in step S6, and if SP ≦ SP1, it is determined in step S4 whether or not the charged amount SOC is greater than or equal to the determination value SOC1. The determination value SOC1 is a lower limit value determined in advance based on charge / discharge efficiency. If SOC ≧ SOC1, “motor running mode (forward)” is selected in step S5, but if SOC <SOC1, the above step is performed. In S6, “ETC mode” is selected.
[0046]
FIG. 7 is a flowchart for explaining an example of engine control and motor control during traveling in the “ETC mode”, and is executed by signal processing of the engine ECU 64, the M / GECU 66, and the like.
[0047]
In step SS1 of FIG. 7, it is determined whether or not the accelerator is ON, that is, whether or not the accelerator pedal 78 is depressed based on the accelerator operation amount θac. If the accelerator is ON, the motor generator 16 is checked in step SS2. The rotational speed Nm is the target motor rotational speed Nm ^* The rotational speed of the motor generator 16 is controlled so that Target motor speed Nm ^* In order to charge the battery 42 by performing regenerative control of the motor generator 16, a predetermined rotational speed in the reverse rotational direction, for example, a constant value such as about −1000 rpm, or a vehicle speed V is set as a palamator. . Further, the rotational speed control is such that the motor rotational speed Nm is the target motor rotational speed Nm. ^* The regenerative braking torque of the motor generator 16 is feedback-controlled so as to substantially match, and the battery 42 is charged with the electric energy generated at this time.
[0048]
In the next step SS3, output control of the engine 14 is performed according to the accelerator operation amount θac. Specifically, in this embodiment, the target motor rotational speed Nm of the motor generator 16 is set. ^* To the target engine speed Ne determined according to the vehicle speed V and the transmission gear ratio γ of the transmission 12 ^* The throttle valve opening degree of the electronic throttle valve 72 is controlled in accordance with the accelerator operation amount θac.
[0049]
On the other hand, when the determination in step SS1 is NO, that is, when coasting with the accelerator off, the engine rotation speed Ne is determined in advance in step SS4. _idl In step SS5, the rotational speed control of the motor generator 16 is stopped and the process proceeds to constant torque control of the motor generator 16.
[0050]
Further, in the last step SS6, engine stall prevention control is executed to prevent the engine stall from occurring due to a rapid decrease in the engine rotational speed Ne. In other words, since the motor generator 16 is controlled in rotation speed in step SS2, the planetary gear as shown by the broken line in FIG. 9 (b) when an excessive traveling load acts on the vehicle due to overcoming an obstacle or the like. As the rotational speed of the ring gear 18r (R) of the device 18 decreases, the rotational speed of the sun gear 18s (S), that is, the engine rotational speed Ne may decrease, causing engine stall.
[0051]
The engine stall prevention control in step SS6 is executed, for example, according to the flowchart shown in FIG. The flowchart of FIG. 8 is executed by the signal processing of the M / GECU 66. In step R1-1, the target engine speed Ne obtained in step SS3 is obtained. ^* Deviation of the actual engine speed Ne from (Ne ^* It is determined whether -Ne) is equal to or greater than a predetermined value α. The predetermined value α is for predicting that the engine stall occurs due to the decrease in the engine rotation speed Ne, and is a relatively large value that is generated when the engine rotation speed Ne is rapidly decreased due to an excessive traveling load, that is, The deviation hardly occurs in normal engine control, and a constant value may be set in advance. However, the smaller the vehicle speed V or the engine rotational speed Ne, for example, the smaller the vehicle speed V or the engine rotational speed Ne. May be set. This step R1-1 functions as an engine stall detection means for predicting an engine stall based on a change in the rotational speed of the engine 14.
[0052]
And the deviation (Ne ^* If -Ne) is greater than or equal to the predetermined value α, it is determined that the possibility of engine stall is high, and step R1-2 is executed to temporarily reduce the torque of the motor generator 16, specifically the regenerative braking torque. . As a result, a change in the rotational speed of the motor generator 16 is allowed, and the rotational speed of the carrier 18c (C) connected to the motor generator 16 decreases as shown in the broken line in FIG. While (R) is decreased (the rotational speed in the reverse rotation direction is increased), the load on the engine 14 connected to the sun gear 18s (S) is reduced, and the decrease in the engine rotational speed Ne is suppressed. Alternatively, the engine rotation speed Ne increases by itself and stalling is prevented. Further, when the torque of the motor generator 16 is reduced in this way, the driving force of the vehicle is reduced, so the time for reducing the torque is 1 second or less, for example, about 300 milliseconds, and the regeneration control of the motor generator 16 is immediately resumed. As a result, the reduction in driving force is minimized. That is, it does not prevent engine stall when the engine 14 or the like is defective and the engine rotation speed Ne decreases. Step R1-2 functions as an engine stall prevention means.
[0053]
As described above, according to the hybrid drive control device 10 of the present embodiment, when traveling in the ETC mode, the deviation (Ne) is determined in step R1-1 in FIG. ^* Based on -Ne), it is determined whether or not there is a high possibility that the engine stalls. If the possibility that the engine stalls is high, the torque of the motor generator 16 is temporarily reduced in step R1-2 to act on the engine 14. Since the load to be reduced is reduced, the engine rotation speed Ne is prevented from being lowered and stalled when an excessive traveling load is applied due to an obstacle or the like.
[0054]
In that case, since the torque control of the motor generator 16 has high responsiveness, engine stall can be effectively prevented. In addition, since the time for reducing the torque of the motor generator 16 is as short as 1 second or less, the reduction of the driving force accompanying the reduction of the torque of the motor generator 16 can be minimized. Also, the deviation (Ne ^* Since the engine stall is predicted based on -Ne), the possibility of the engine stall can be detected when the engine rotational speed Ne is relatively high, and the engine stall can be prevented with a high possibility.
[0055]
The hybrid drive control apparatus 10 of the present embodiment has a “direct connection mode” in which the engine 14 is driven as a drive source during forward travel, a “motor travel mode” in which the motor generator 16 is driven as a drive source, and the “ETC mode”. Since the engine 14 is operated or stopped depending on the driving state, even if the engine 14 is stopped due to the engine stall, the driver cannot be determined, and the engine stall is prevented with a high possibility, so that the vehicle Improves quality and reliability.
[0056]
Next, another embodiment of the present invention will be described.
FIG. 10 is a flowchart corresponding to FIG. 8, which is another aspect of the engine stall prevention control of step SS6 in FIG. 7, and in step R2-1, per certain time (for example, one cycle of the flowchart of FIG. 7). It is determined whether or not the change amount ΔNe of the engine rotation speed Ne is equal to or less than a predetermined value β. The predetermined value β is for predicting that the engine stall occurs due to a decrease in the engine rotational speed Ne, and is a relatively large negative value generated when the engine rotational speed Ne is suddenly decreased due to an excessive traveling load. That is, the amount of change hardly occurs in normal engine control, and a constant value may be determined in advance. For example, the lower the vehicle speed V or the engine rotation speed Ne, the lower the vehicle speed V or the engine rotation speed Ne, for example. A small value (close to 0) may be set. This step R2-1 functions as an engine stall detection unit that predicts an engine stall based on a change in the rotational speed of the engine 14.
[0057]
If the change amount ΔNe is equal to or less than the predetermined value β, it is determined that the possibility of engine stall is high, and step R2-2 is executed. Step R2-2 functions as engine stall prevention means, and prevents engine stall in the same manner as step R1-2 in FIG. In this case, the same effect as in the above embodiment can be obtained.
[0058]
FIG. 11 is a flowchart corresponding to FIG. 8 and is still another aspect of the engine stall prevention control in step SS6 in FIG. 7. In step R3-1, the engine rotational speed Ne is a predetermined lower limit value Ne. _min It is determined whether or not the following has occurred. Lower limit value Ne _min Is for predicting the occurrence of engine stall due to a decrease in the rotational speed Ne, and is a value that is generated when the engine rotational speed Ne is abnormally decreased due to an excessive traveling load or the like, that is, almost occurs in normal engine control. The engine speed is an idle speed Ne. _idl It is a constant value that is lower and higher than the rotational speed at which the engine 14 misfires. This step R3-1 functions as an engine stall detection means for detecting whether or not there is a possibility of engine stall.
[0059]
The engine speed Ne is the lower limit value Ne. _min If it is below, it is determined that the possibility of engine stall is high, and step R3-2 is executed. Step R3-2 functions as engine stall prevention means, and prevents engine stall in the same manner as step R1-2 in FIG. In this case, the engine speed Ne is the lower limit value Ne. _min In order to determine the possibility of engine stall depending on whether or not it is below, there is a possibility that the determination of engine stall may be delayed compared to the previous embodiment, but it is determined that the engine stalls more than necessary and the driving force is reduced Is suppressed.
[0060]
FIG. 12 is a flowchart corresponding to FIG. 8 and is still another aspect of the engine stall prevention control in step SS6 in FIG. 7. In step R4-1, the steps R1-1, R2-1, or R3 are performed. The possibility of engine stall is determined in the same manner as -1. If there is a possibility of engine stall, the control of the motor generator 16 is switched from the rotational speed control to the torque control in step R4-2, and the engine load is reduced by controlling to a predetermined regenerative braking torque. The torque value at this time is determined in consideration of the gear ratio ρ and the like so that the rotational speed Nm of the motor generator 16 changes depending on the traveling load, and is set to a value that is, for example, about one digit smaller than the engine torque. As a result, the load on the engine 14 is reduced, the decrease in the engine rotational speed Ne is suppressed, or the engine rotational speed Ne is increased by itself to prevent the stall, and the same effect as in the above embodiments can be obtained. It is done. Step R4-1 functions as engine stall detection means, and step R4-2 functions as engine stall prevention means.
[0061]
The torque control in step R4-2 is performed for 1 second or less, for example, about 300 msec as in the above embodiments. In the subsequent step R4-3, the control immediately returns to the rotation speed control and the target motor rotation speed Nm. ^* Gradually change to the normal set value.
[0062]
The vehicle drive control device of FIG. 13 includes a rear motor generator 90 as a second drive source in addition to the hybrid drive control device 10, and is electrically connected to the battery 42 via an inverter 92. Power running control and regenerative control are designed. In addition, the rear wheel 96 is mechanically connected to the left and right rear wheels 96 via the differential device 94 and is controlled by power running, and the regenerative braking force is applied to the rear wheel 96 by regenerative control.
[0063]
Also in such a vehicle drive control device, the front-side hybrid drive control device 10 can basically perform the same control as in each of the above embodiments. In that case, in the engine stall prevention control of step SS6 of FIG. 7, for example, as shown in the flowchart of FIG. 14, the assist control can be performed using the rear motor generator 90. That is, in step R5-1, engine stall is predicted in the same manner as in the above embodiments, and in step R5-2, the torque of the motor generator 16 is temporarily set to 0 to prevent engine stall, while step R5- 3, the driving force by the rear motor generator 90 is made larger than usual, and the reduction of the driving force of the hybrid drive control device 10 on the front side due to the execution of step R5-2 is assisted on the rear wheel 96 side. The amount of increase in driving force by the rear motor generator 90 is preferably substantially the same as the amount of decrease in driving force associated with the execution of step R5-2, but may be increased by a predetermined amount. It is set appropriately according to the torque capacity of the side motor generator 90 and the like. Step R5-1 functions as engine stall detection means, step R5-2 functions as engine stall prevention means, and step R5-3 functions as auxiliary drive means. In step R5-2, the torque of the motor generator 16 is temporarily set to 0. However, it may be reduced by a predetermined amount as in the above embodiments.
[0064]
In this way, when the torque of the motor generator 16 is set to 0 in order to prevent engine stall, the driving force of the rear wheel 96 by the rear motor generator 90 is increased. The reduction in driving force at the time is reduced. In addition, since the decrease in driving force is reduced in this way, the time for temporarily turning off the motor torque in step R5-2 can be lengthened, so that a sufficient recovery time can be secured from the torque drop of the engine 14. become. In other words, the engine stall can be more reliably prevented by continuing the time for setting the motor torque to 0 in step R5-2 for 1 second or longer while suppressing a decrease in the driving force of the entire vehicle. is there.
[0065]
As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating a hybrid drive control device to which the present invention is applied.
FIG. 2 is a skeleton diagram showing a power transmission system of the hybrid drive control device of FIG. 1;
FIG. 3 is a circuit diagram showing a part of the hydraulic control circuit of FIG. 1;
4 is a diagram for explaining the relationship between several travel modes established in the hybrid drive control device of FIG. 1 and the operating states of clutches and brakes. FIG.
5 is a collinear diagram showing the relationship between the rotational speeds of the rotating elements of the planetary gear device in the ETC mode, the direct connection mode, and the motor travel mode (forward) of FIG.
6 is a flowchart illustrating an example of an operation of switching to “motor travel mode”, “ETC mode”, or “direct connection mode” in accordance with the driving state during forward travel in the hybrid drive control device of FIG. 1;
FIG. 7 is a flowchart for explaining the operation when traveling in the ETC mode in the hybrid drive control device of FIG. 1;
FIG. 8 is a flowchart illustrating specific contents of engine stall prevention control in step SS7 in FIG.
9 is a collinear diagram illustrating changes in the rotational speed of each rotating element of the planetary gear device when an excessive traveling load is applied during traveling in the ETC mode. FIG. 9 (a) is an engine stall prevention according to the flowchart of FIG. When the control is performed, (b) is a case where the engine stall prevention control is not performed.
FIG. 10 is a flowchart illustrating another example of engine stall prevention control in step SS7 in FIG.
FIG. 11 is a flowchart illustrating yet another example of engine stall prevention control in step SS7 in FIG.
FIG. 12 is a flowchart illustrating yet another example of engine stall prevention control in step SS7 in FIG.
FIG. 13 is a schematic configuration diagram illustrating another example of a vehicle drive control device to which the present invention is applied.
14 is a flowchart for explaining an example of engine stall prevention control in the vehicle drive control device of FIG. 13, corresponding to FIG.
[Explanation of symbols]
10: Hybrid drive control device (vehicle drive control device) 14: Engine
16: Motor generator (electric motor) 18: Planetary gear device (combining and distributing device) 18s: Sun gear (first rotating element) 18c: Carrier (second rotating element) 18r: Ring gear (third rotating element) 52: Drive wheel 66: M / GECU 90: Rear motor generator (second drive source) 96: Rear wheel
Steps R1-1, R2-1, R3-1, R4-1, R5-1: Engine stall detection means
Steps R1-2, R2-2, R3-2, R4-2, R5-2: Engine stall prevention means
Step R5-3: Auxiliary drive means

Claims (5)

A first rotating element connected to an engine that operates by combustion of fuel, a second rotating element connected to a motor generator , and a third rotating element that outputs to a drive wheel, and rotation of the three rotating elements A gear-type synthesizing / distributing device configured such that the third rotating element is positioned between the first rotating element and the second rotating element in a collinear diagram showing a relationship between speeds;
The first rotating element, a second rotating element, and the third rotating element is rotatable relative state, the addition of engine torque to the first rotating element is operated the engine, Rukoto to power the motor-generator In the vehicle drive control device having an ETC mode in which the third rotating element is rotated to travel,
Engine stall detection means for detecting whether or not the engine rotational speed is likely to stall when traveling in the ETC mode;
An engine stall prevention means for reducing the load acting on the engine by reducing the power generation amount of the motor generator when it is determined by the engine stall detection means that there is a possibility of stall;
A vehicle drive control device comprising: 2. The vehicle drive control device according to claim 1, wherein a time period during which the power generation amount of the motor generator is reduced by the engine stall prevention unit is 1 second or less. The vehicle drive control device according to claim 1 or 2 , wherein the engine stall detection means predicts a stall based on a change in the rotational speed of the engine. The driving wheel is in either of the front and rear wheels of the vehicle, any one of the claims 1-3, characterized in that it comprises a second driving source for driving the other front wheel and the rear wheel The vehicle drive control device according to the item. 5. The vehicle drive control device according to claim 4 , further comprising: an auxiliary drive unit that increases the driving force of the second drive source when the engine stall prevention unit reduces the load on the engine.

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