JP2002118902A - Vehicle drive control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] When running by operating both an engine and a motor generator connected to a planetary gear unit, when an excessive running load is applied due to an obstacle or the like, the engine rotation speed is reduced and a stall is caused. To prevent SOLUTION: When the vehicle is driven while engaging a second clutch C2 and disengaging a first clutch C1 and a first brake B1 to operate both an engine 14 and a motor generator 16, the engine rotation speed Ne decreases. Whether or not there is a possibility of stall is detected based on a change in rotation speed or the like. If there is a possibility of stall, the torque of the motor generator 16 is temporarily reduced to reduce the load acting on the engine 14. I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a vehicle, and more particularly, to a case in which an electric motor outputs a reaction torque against an output torque of the engine to drive the vehicle. The present invention relates to a technology for preventing a stall.

[0002]

2. Description of the Related Art (a) It has a first rotating element connected to an engine operated by fuel combustion, a second rotating element connected to a motor generator, and a third rotating element outputting to driving wheels. Equipped with a gear-type composite dispensing device,
(b) When the first rotating element, the second rotating element, and the third rotating element are relatively rotatable, the engine and the motor generator are operated together to apply torque to the first rotating element and the second rotating element. In addition, a drive control device for a vehicle that travels while rotating a third rotating element is known. For example, an apparatus described in Japanese Patent Application Laid-Open No. 9-193676 is one example of such an apparatus, in which a planetary gear unit is used as a combining and distributing apparatus.

Although FIG. 1 is not yet known, FIG. 1 shows a case where a double pinion type planetary gear set 18 is used as a synthesizing and distributing apparatus, and a sun gear 1 as a first rotating element.
8s, the engine 14 is connected, the motor generator 16 is connected to the carrier 18c as the second rotating element,
A ring gear 18r as a third rotating element is connected to the transmission 12 via a second clutch C2 to output to a drive wheel. Then, the first clutch C1 and the first brake B1 are released, and the second clutch C2 is released.
In the ETC mode in which is engaged, for example, FIG.
The engine 14 is operated as shown in FIG.
By applying a forward torque to (S) and applying regenerative braking torque to the carrier 18c (C) by performing regenerative control with the motor generator 16 rotating in the reverse direction, the ring gear 18r (R) is rotated in the forward direction. Can travel.

[0004]

However, in such a vehicle drive control device, for example, FIG.
9A, when a large load acts on an obstacle or sudden braking while driving in the ETC mode, and the vehicle speed and further the rotation speed of the ring gear 18r (R) suddenly decrease.
(B), the engine speed (rotation speed of the sun gear 18s (S)) decreases as indicated by the broken line, and there is a possibility that the engine stalls, that is, the engine stalls and misfires, so that torque cannot be generated. In particular, when the rotation speed is controlled so that the motor rotation speed becomes a predetermined value (minus) in order to perform the regenerative control by rotating the motor generator 16 in the reverse direction, the decrease in the vehicle speed is absorbed by the decrease in the engine rotation speed. The possibility of engine stall is high. When the operation of the engine 14 is appropriately stopped, for example, by driving the motor generator 16 with the first clutch C1 engaged as in the hybrid drive control device of FIG. Therefore, it is strongly desired to prevent the occurrence of engine stall.

[0005] The cause of the engine stall is as follows.
For example, in FIG. 9B, instead of the rotation speed of the ring gear 18r (R) decreasing, the motor generator 16
The regenerative braking torque of the carrier 18c
When the rotation speed of (C) changes (approaches 0),
Various forms are conceivable according to the connection state of the engine and the motor generator, for example, there is a possibility that the rotation speed of the sun gear 18s (S) is reduced and the stall is caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to stall an engine by applying an excessive load when the engine and the electric motor are operated together. Is to prevent

[0007]

In order to achieve the above object, a first aspect of the present invention has an engine and an electric motor that operate by burning fuel, and the electric motor generates a reaction torque against an output torque of the engine. In the vehicle drive control device that combines the output torques of the engine and the electric motor and outputs the combined output torque to the drive shaft, there is a possibility that (a) the rotation speed of the engine is reduced and the engine is stalled. And (b) a load acting on the engine by reducing the torque of the electric motor when the engine stall detection means determines that there is a possibility of a stall. And engine stall prevention means for reducing engine stall.

According to a second aspect of the present invention, there is provided (a) a first rotating element connected to an engine operated by fuel combustion, a second rotating element connected to an electric motor, and a third rotating element outputting to driving wheels. A gear-type combining and distributing device having
(b) When the first rotating element, the second rotating element, and the third rotating element are relatively rotatable, the engine and the electric motor are operated together to apply torque to the first rotating element and the second rotating element. And (c) an engine stall detecting means for detecting whether or not the rotational speed of the engine is likely to stall due to a decrease in the rotational speed of the engine. (D) engine stall prevention means for reducing the torque acting on the engine by reducing the torque of the electric motor when the engine stall detection means determines that there is a possibility of a stall; It is characterized by having.

According to a third aspect of the present invention, in the vehicle drive control device according to the second aspect of the present invention, the time during which the torque of the electric motor is reduced by the engine stall prevention means is 1 second or less.

A fourth invention has an engine and an electric motor that operate by burning fuel, and outputs a reaction torque to the output torque of the engine by controlling the rotation speed of the electric motor. And (a) engine stall detection means for detecting whether or not there is a possibility that the rotation speed of the engine is reduced and the vehicle is stalled. (B) engine stall prevention means for stopping the rotation speed control of the electric motor to reduce the load on the engine when the engine stall detection means determines that there is a possibility of a stall; It is characterized by having.

A fifth aspect of the present invention provides (a) a first rotating element connected to an engine which operates by burning fuel, a second rotating element connected to an electric motor, and a third rotating element outputting to driving wheels. A gear-type combining and distributing device having
(b) operating the engine to apply torque to the first rotating element while the first rotating element, the second rotating element, and the third rotating element are relatively rotatable, and the second rotating element By controlling the rotation speed of the electric motor so that the rotation speed becomes a predetermined rotation speed, in the vehicle drive control device that travels by rotating the third rotation element, (c) the rotation speed of the engine decreases and the engine stalls. Engine stall detection means for detecting whether there is a possibility or not, (d)
Engine stall prevention means for stopping the rotation speed control of the electric motor to reduce the load on the engine when the engine stall detection means determines that there is a possibility of stall. And

According to a sixth aspect of the present invention, in the vehicle drive control device according to any one of the first to fifth aspects, the engine stall detecting means predicts a stall based on a change in the rotation speed of the engine. It is characterized by.

According to a seventh aspect of the present invention, in the vehicle drive control device according to any one of the first to sixth aspects, the driving wheel is one of a front wheel and a rear wheel of the vehicle, and the other of the front wheel and the rear wheel. And a second drive source for driving.

According to an eighth aspect of the present invention, in the vehicle drive control device according to the seventh aspect of the present invention, when the load on the engine is reduced by the engine stall prevention means, an auxiliary drive means for increasing a drive force by the second drive source. It is characterized by having.

[0015]

In the vehicle drive control apparatus according to the first aspect of the invention, the engine stall detecting means detects whether or not the engine may be stalled, and determines that there is a possibility of stalling. In this case, the torque of the electric motor is reduced by the engine stall prevention means, so that the load acting on the engine is reduced, and the reduction of the engine rotation speed is suppressed, or the engine rotation speed is increased by itself to prevent engine stall. Is done. In this case, the torque control of the electric motor provides high responsiveness, so that engine stall can be effectively prevented.

The second invention is substantially one embodiment of the first invention, and has the same effects as the first invention.

In the third aspect of the present invention, since the time during which the torque of the electric motor is reduced by the engine stall prevention means is 1 second or less, the decrease in the driving force due to the decrease in the torque of the electric motor can be suppressed in an extremely short time.

According to a fourth aspect of the present invention, the rotational speed control of the electric motor is stopped to reduce the load on the engine. The torque applied to the engine is reduced by substantially reducing the torque of the electric motor. The same effect as the first invention can be obtained.
The same applies to the fifth invention.

In the sixth invention, the engine stall detecting means predicts a stall based on a change in the engine speed, so that the possibility of the engine stall can be detected at a stage where the engine speed is relatively high, and the engine stall is detected in advance. Can be prevented with a high probability.

In the eighth invention, when the load on the engine is reduced by the engine stall prevention means, the driving force by the second driving source is increased by the auxiliary driving means, so that the driving force is reduced due to the reduction of the engine load. It is reduced as a whole vehicle. Further, since the reduction in the driving force is reduced in this manner, the reduction time of the engine load for preventing the engine stall can be lengthened, and the recovery time from the drop in the engine torque can be sufficiently secured. become.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A double pinion type or a single pinion type planetary gear device is preferably used as the gear type compound distributing device, but a bevel gear type differential gear device can also be used. . Various modes of connection of the engine and the electric motor to the combining and distributing device are possible.

[0022] The above-mentioned synthesizing and distributing apparatus is configured such that, 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 rotation speed of the first rotation element also decreases. There is a possibility that an engine stall may occur when the vehicle speed suddenly decreases due to an obstacle, a brake operation, or the like. In a case where the rotation speed of the third rotating element is substantially constant, the rotation speed of the first rotating element is reduced due to a change in the rotation speed of the second rotating element accompanying an increase in the torque of the electric motor. May cause engine stall when the motor torque increases rapidly.

Specifically, when the combining and distributing device is a double pinion type planetary gear device, for example, (a) an engine is connected to a sun gear and an electric motor is connected to a carrier, while (b) the planetary gear device is A first brake for connecting the ring gear to the case, a first clutch for connecting the carrier to the transmission, and a second clutch for connecting the ring gear to the transmission. The present invention is applied when the vehicle is traveling in a traveling mode in which the first clutch and the first brake are released and the second clutch is engaged. In this case, the engine may stall when the vehicle speed suddenly decreases due to obstacles or brake operation, and the motor torque (regenerative braking torque for reverse rotation and power running torque for forward rotation) may increase. There is a possibility that engine stall may occur even when the number of vehicles increases.

The electric motor may function only as an electric motor that is rotationally driven by electric energy, may function only as a generator that generates electric power by being driven to rotate and generates a braking torque, or may be an electric motor and a generator. It may be a motor generator having both functions of the machine.

The engine stall detecting means is, for example, the sixth
It is desirable to predict the stall based on a change in the engine speed as in the present invention. However, it may be determined whether the engine speed has fallen below a predetermined lower limit, or the vehicle speed may be reduced. It is also possible to determine the possibility of engine stall from other physical quantities related to the load of the engine, such as speed. In addition, various modes can be adopted, such as determining the possibility of engine stall when the vehicle speed or the engine rotation speed falls below a predetermined value.

[0026] The engine stall prevention means of the second invention comprises:
For example, the motor is configured so that the torque of the motor is 0, that is, the motor is rotatable. However, the torque of the motor is reduced by a fixed amount or a fixed ratio, or reduced by a predetermined amount according to the possibility of engine stall. For example, various modes can be adopted.

In the third aspect, the time for reducing the torque of the motor is 1 second or less, and more preferably 500 ms or less. Even when the load on the engine is reduced by other means, the reduction time is desirably 1 second or less in order to minimize the reduction in driving force. Note that it may be determined whether or not the engine stall has been avoided based on the engine rotation speed and its change, and the engine load reduction control by the engine stall prevention means may be stopped.

The fourth and fifth aspects of the present invention stop the rotation speed control of the electric motor to reduce the load on the engine. When the rotation speed of the electric motor is controlled, even when a large load is applied from the outside, control is performed to increase the torque in order to maintain the rotation speed. Therefore, the large load becomes the load on the engine side as it is, and the possibility of causing the engine stall increases. Therefore, by stopping such rotation speed control of the electric motor, a large external load can be prevented from becoming a load on the engine side, and the engine load can be reduced. Preferably, the control is shifted to the torque control after the rotation speed control of the electric motor is stopped. In this case, when returning to the rotation speed control, it is desirable to gradually change the target motor rotation speed to return to the normal value.

The above-mentioned rotation speed control is configured, for example, to control the motor torque so that the motor rotation speed becomes a predetermined target motor rotation speed. In this case, the engine control is performed by the driver's output such as the accelerator operation amount. The torque, that is, the throttle valve opening, is controlled in accordance with the required amount, or the throttle valve is opened from the target motor rotation speed of the electric motor to a predetermined target engine rotation speed determined according to the vehicle speed or the transmission gear ratio. It is configured to control the degree and the like.

[0030] The engine stall detecting means of the sixth invention comprises:
For example, the change amount Δ of the engine rotation speed Ne per fixed time
Whether Ne is equal to or less than a predetermined value (minus), or the target engine speed Ne ^* and the actual engine speed N
It is configured to determine whether the deviation from Ne (Ne ^* −Ne) is equal to or greater than a predetermined value. Since the deviation when the engine rotational speed Ne, etc. abrupt change in the traveling load changes suddenly (Ne ^* -Ne) increases, the deviation (Ne ^* -
The case where the engine stall is predicted based on whether Ne) is equal to or greater than a predetermined value is also based on a change in the rotation speed of the engine.

The variation ΔNe and the deviation (Ne ^* −Ne)
The predetermined value (determination value) for predicting the engine stall may be a constant value, but the vehicle speed, the engine rotation speed, and the like may be set as parameters.

In the eighth aspect of the present invention, it is preferable that the amount of increase of the driving force by the second driving source by the auxiliary driving means substantially coincides with the amount of reduction of the driving force due to the reduction of the engine load by the engine stall prevention means. Alternatively, it may be increased by a predetermined fixed 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, so that all of the driving forces required according to the output request amount of the driver are set to the second. It may be generated by a driving source.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a hybrid drive control device 10 as a vehicle drive control device according to one embodiment of the present invention.
FIG. 2 is a skeleton diagram including a transmission 12. The hybrid drive control device 10 includes an engine 14, such as an internal combustion engine, which generates power by fuel combustion, an electric motor, and a generator. Motor generator 16 to be used and double pinion type planetary gear set 18
It is mounted horizontally on an FF (front engine / front drive) vehicle or the like and used. The engine 14 is connected to the sun gear 18s of the planetary gear set 18, the motor generator 16 is connected to the carrier 18c, and the ring gear 18r is connected to the first brake B.
1 is connected to the case 20.
The carrier 18c is connected to the input shaft 22 of the transmission 12 via a first clutch C1, and the ring gear 18r is connected to the input shaft 22 via a second clutch C2. The motor generator 16 corresponds to an electric motor, the planetary gear unit 18 corresponds to a gear-type combining and 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. I do.

Each of the clutches C1 and C2 and the first brake B1 is a wet multiple disc hydraulic friction engagement device that is frictionally engaged by a hydraulic actuator. It is adapted to be combined. 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 generating device 26 including the electric pump is connected to the manual valve 2.
The clutch 8 is supplied to each of the clutches C1, C2 and the brake B1 in accordance with the shift position of the shift lever 30 (see FIG. 1) via the control lever 8. The shift lever 30 is a shift operation member operated by the driver. In this embodiment, the shift lever 30 is selectively operated in five shift positions of “B”, “D”, “N”, “R”, and “P”. The manual valve 28 is connected to a shift lever 30 via a cable, a link, or the like, and is mechanically switched according to the operation of the shift lever 30.

The "B" position is a shift position in which a relatively large power source brake is generated by a downshift of the transmission 12 during forward running, and the "D" position is a shift position in which the vehicle travels forward. In the shift position, 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 C1 via the shuttle valve 31. The "N" range is a shift position for cutting off the transmission of power from the power source, the "R" position is a shift position for reverse running, and the "P" position is for cutting off the transmission of power from the power source and a parking lock device (not shown). The shift position is a shift position in which the rotation of the drive wheels is mechanically prevented by the above operation. In 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, and in the above “R” position, the return port 28c is connected to the output port 2c.
The original pressure PC is supplied from the shuttle valve 31 to the first clutch C1 via 8d.

The clutches C1, C2 and the brake B1
Are provided with control valves 32, 34 and 36, respectively, so that the oil pressures P _C1 , P _C2 and P _B1 thereof are controlled. ON for hydraulic pressure P _C1 of clutch C1
The pressure is regulated by the -OFF valve 38, and the pressure of the clutch C2 and the brake B1 is regulated by the linear solenoid valve 40.

Each running mode shown in FIG. 4 is established according to the operating states of the clutches C1, C2 and the brake B1. That is, in the "B" range or the "D" range, any one of the "ETC mode", the "direct connection mode", and the "motor running mode (forward)" is established. In the "ETC mode", the second clutch C2 is engaged. The first clutch C1 and the first brake B
1 is released, in other words, with the sun gear 18s, the carrier 18c, and the ring gear 18r relatively rotatable, the engine 14 and the motor generator 16 are operated together to apply torque to the sun gear 18s and the carrier 18c to rotate the ring gear 18r. Then, the vehicle travels forward. In the "direct connection mode", the clutches C1, C
With the second brake engaged and the first brake B1 released, the engine 14 is operated to drive the vehicle forward.
In the “motor running mode (forward)”, the first clutch C1 is engaged, and the second clutch C2 and the first clutch C2 are engaged.
With the brake B1 released, the motor generator 1
6 is operated to drive the vehicle forward. In the “motor running mode (forward)”, the regenerative control of the motor generator 16 is performed when the accelerator is turned off, so that the battery 42 (see FIG. 1) is generated by the kinetic energy of the vehicle and the braking force is applied to the vehicle. Can be generated.

FIG. 5 is an alignment chart showing the operating state of the planetary gear set 18 in the forward mode, where "S" indicates the sun gear 18s, "R" indicates the ring gear 18r, and "C" indicates the carrier 18c. , Their spacing is the gear ratio ρ
(= Number of teeth of sun gear 18s / number of teeth of ring gear 18r)
Is determined by Specifically, assuming that the interval between “S” and “C” is 1, the interval between “R” and “C” becomes ρ, and in this embodiment, ρ is about 0.6. Further, the torque ratio in the ETC mode of (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 a steady state, the torque obtained by adding the motor torque Tm and the engine torque Te is CV
It becomes T 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.

Returning to FIG. 4, "N" range or "P"
In the range, either “neutral” or “charge / eng start mode” is established, and “neutral”
Then, all of the clutches C1, C2 and the first brake B1 are released. In the “charging / Eng start mode”, the clutches C1 and C2 are released, the first brake B1 is engaged, the motor generator 16 is rotated in the reverse direction, and the engine 14 is started.
The motor 42 is rotated and driven via the motor 8, the regenerative control of the motor generator 16 is performed to generate electric power, and the battery 42 (see FIG. 1) is charged.

In the "R" range, "motor traveling mode (reverse)" or "friction traveling mode" is established. In "motor traveling mode (reverse)", the first clutch C1 is engaged and the second clutch is engaged. With the C2 and the first brake B1 released, the motor generator 16 is rotated in the reverse direction to rotate the carrier 18c and the input shaft 22 in the reverse direction, thereby causing the vehicle to travel backward. The "friction running mode" is executed when an assist request is issued during the reverse running in the "motor running mode (reverse)", in which 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. It assists reverse running by applying force.

The transmission 12 is a belt-type continuously variable transmission.
From the output shaft 44 via a counter gear 46, the differential 4
Power is transmitted to the ring gear 50 of the differential gear 8 and the differential gear 4
The power is distributed to the left and right drive wheels (front wheels in this embodiment) 52 by the reference numeral 8.

The hybrid drive control device 10 of the present embodiment
The driving mode is switched by the HVECU 60 shown in FIG. HVECU 60 is C
The electronic throttle ECU 62, the engine ECU 64, and the M / GECU 6 are provided with a PU, a RAM, a ROM, and the like, and execute signal processing in accordance with a program stored in the ROM while using a temporary storage function of the RAM.
6, ON of the T / MECU 68 and the hydraulic control circuit 24;
OFF valve 38, linear solenoid valve 40, engine 14
The starter 70 is controlled. Electronic throttle ECU
62 controls the opening and closing of an electronic throttle valve 72 of the engine 14; the engine ECU 64 controls the engine output based on the fuel injection amount of the engine 14, the variable valve timing mechanism, the ignition timing, etc., and the M / GE ECU 66 controls the inverter 74. And controls the power running torque and the regenerative braking torque of the motor generator 16 through the T / ME
The CU 68 determines the speed ratio γ of the transmission 12 (= the input shaft rotation speed N
in / output shaft rotation speed Nout) and belt tension. The hydraulic control circuit 24 includes a circuit for controlling the speed ratio γ of the transmission 12 and the belt tension. The starter 70 is an electric motor that cranks the engine 14 by engaging a pinion provided on the motor shaft with a ring gear provided on a flywheel or the like of the engine 14.

The HVECU 60 is supplied with a signal representing an operation amount θac of an accelerator pedal 78 as an accelerator operation member from an accelerator operation amount sensor 76.
A signal indicating the operation position (shift position) of the shift lever 30 is supplied from the shift position sensor 80. 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, respectively, the engine rotation speed (rotation speed) Ne, the motor rotation speed (rotation speed) Nm, the input shaft Signals representing the rotation speed (the rotation speed of the input shaft 22) Nin and the output shaft rotation speed (the rotation speed of the output shaft 44) Nout are supplied. The output shaft rotation speed Nout corresponds to the vehicle speed V. In addition, various signals indicating the operating state, such as the state of charge SOC of the battery 42, are supplied. The state of charge SOC may be simply a battery voltage, or may be obtained by successively integrating the amount of charge and discharge. The accelerator operation amount θac represents a driver output request amount.

FIG. 6 shows the above-described "ETC mode", "direct connection mode", and "motor drive mode (depending on the driving state) during forward running with the shift lever 30 being operated to the" D "position or the" B "position. HVECU is a flowchart for explaining the operation when switching between “forward”) as appropriate.
This is executed by 60 signal processings.

In step S1 of FIG. 6, the shift lever 3
It is determined whether the 0 shift position is "D" or "B". If it is "D" or "B", it is determined in step S2 whether the vehicle speed V is equal to or less than the determination vehicle speed V1. Judgment vehicle speed V1
Is, for example, 15 km / km based on the output characteristics and energy consumption of the motor generator 16 and the engine 14.
A constant value such as about h is set. If V> V1, the "direct connection mode" is selected in step S7. If V ≦ V1, the driver's output request amount SP is determined in step S3 to the determination value SP1. It is determined whether or not: The required output amount SP is obtained from a predetermined arithmetic expression or map based on the accelerator operation amount θac, the vehicle speed V, and the like, and the determination value SP1 is set so that a necessary driving force cannot be obtained by, for example, the motor generator 16 alone. And the speed ratio γ is set as a parameter. If SP> SP1, "ETC mode" is selected in step S6, and if SP≤SP1, in step S4 the storage amount SOC is equal to the determination value SOC1.
It is determined whether the above is not true. The determination value SOC1 is a lower limit value that is predetermined based on charge / discharge efficiency or the like, and SOC ≧ SO
If it is C1, the "motor running mode (forward)" is selected in step S5, but if SOC <SOC1, the "ETC mode" is selected in step S6.

FIG. 7 is a flowchart illustrating an example of engine control and motor control during traveling in the "ETC mode".
66 and the like.

In step SS1 of FIG. 7, the accelerator is turned on.
It is determined whether or not the accelerator pedal 78 is being depressed based on the accelerator operation amount θac. If the accelerator is ON, the rotation speed Nm of the motor generator 16 becomes the target motor rotation speed N in step SS2.
The rotation speed of the motor generator 16 is controlled so as to be m ^* . The target motor rotation speed Nm ^* is a predetermined rotation speed in the reverse rotation direction to charge the battery 42 by regeneratively controlling the motor generator 16 to generate electric power.
For example, a constant value such as about -1000 rpm, or the vehicle speed V
Etc. are set as Pamelata. The rotation speed control is performed by setting the motor rotation speed Nm to the target motor rotation speed Nm ^*.
The regenerative braking torque of the motor generator 16 is feedback-controlled so as to substantially coincide with the above, and the battery 42 is charged with the electric energy generated at this time.

In the next step SS3, the output of the engine 14 is controlled in accordance with the accelerator operation amount θac. Specifically, in the present embodiment, the vehicle speed V and the gear ratio γ of the transmission 12 are calculated based on the target motor rotation speed Nm ^* of the motor generator 16.
The throttle valve opening and the like of the electronic throttle valve 72 are controlled according to the accelerator operation amount θac so that the target engine rotation speed Ne ^* is obtained according to the following.

On the other hand, if the determination in step SS1 is NO, that is, if the vehicle is coasting with the accelerator off, the output of the engine 14 is set in step SS4 so that the engine speed Ne becomes the predetermined idle speed _Neidl. While performing control, in step SS5,
The rotation speed control of the motor generator 16 is stopped, and the process proceeds to the constant torque control of the motor generator 16.

In the last step SS6, engine stall prevention control is executed to prevent engine stall from occurring due to a sudden decrease in the engine rotation speed Ne or the like. That is, since the rotation speed of the motor generator 16 is controlled in step SS2, when an excessive running load acts on the vehicle due to, for example, overcoming an obstacle,
As shown by the broken line in FIG. 9B, the rotation speed of the ring gear 18r (R) of the planetary gear device 18 decreases, and the rotation speed of the sun gear 18s (S), that is, the engine rotation speed Ne, decreases. May occur.

The engine stall prevention control in step SS6 is executed, for example, according to a flowchart shown in FIG. 8 is executed by the signal processing of the M / GECU 66. In step R1-1, the target engine speed N obtained in step SS3 is determined.
It is determined whether a deviation (Ne ^* -Ne) obtained by subtracting the actual engine rotation speed Ne from e ^* is equal to or greater than a predetermined value α. The predetermined value α is for predicting that an engine stall will occur due to a decrease in the engine rotation speed Ne, and is a relatively large value generated when the engine rotation speed Ne suddenly decreases due to an excessive running load, that is, This is a deviation that hardly occurs in normal engine control, and may be set to a constant value in advance. For example, the vehicle speed V or the engine speed Ne is used as a parameter, and the smaller the vehicle speed V or the engine speed Ne, the smaller the value. May be set. This step R1-1 functions as engine stall detecting means for predicting engine stall based on a change in the rotation speed of the engine 14.

If the deviation (Ne ^* -Ne) is equal to or greater than the predetermined value α, it is determined that there is a high possibility that the engine will stall, and step R1-2 is executed. Reduces the regenerative braking torque temporarily. As a result, the rotation speed of the motor generator 16 is allowed to change, and the carrier 18c connected to the motor generator 16 as shown by a broken line in FIG.
The rotation speed of (C) is reduced (the rotation speed in the reverse rotation direction is increased) with the decrease of the vehicle speed V, that is, the decrease of the ring gear 18r (R), while the rotation speed of the engine 14 connected to the sun gear 18s (S) is reduced. The load is reduced, and a decrease in the engine speed Ne is suppressed, or the engine speed Ne is increased by itself to prevent stall. When the torque of motor generator 16 is reduced in this manner, the driving force of the vehicle is reduced. Therefore, the time for reducing the torque is 1 second or less, for example, about 300 msec, and the regenerative control of motor generator 16 is immediately restarted. By doing
The reduction of the driving force is minimized.
That is, it does not prevent the engine stall when the engine 14 or the like has a problem and the engine rotation speed Ne decreases. Step R1-2 functions as engine stall prevention means.

As described above, according to the hybrid drive control device 10 of the present embodiment, when the vehicle is traveling in the ETC mode, the possibility of the engine stall based on the deviation (Ne ^* −Ne) in step R1-1 in FIG. Is high or not,
Step R1 if the possibility of engine stall is high
Since the torque acting on the engine 14 is reduced by temporarily lowering the torque of the motor generator 16 at -2, the engine rotation speed Ne decreases when an excessive running load acts on an obstacle or the like. And stall is prevented.

In this case, since the torque control of the motor generator 16 has high responsiveness, the engine stall can be effectively prevented. Also, the motor generator 1
Since the time for reducing the torque of No. 6 is extremely short, that is, 1 second or less, the reduction of the driving force due to the reduction of the torque of the motor generator 16 can be minimized. The deviation (N
Since the engine stall is predicted based on e ^* -Ne), the possibility of the engine stall can be detected at a stage where the engine rotation speed Ne is relatively high, and the engine stall can be prevented with a high possibility.

The hybrid drive control device 10 of the present embodiment
The "direct drive mode" in which the vehicle travels using the engine 14 as a drive source during forward travel, the "motor drive mode" in which the vehicle travels with the motor generator 16 as a drive source, and the "ETC
There is a "mode", and the engine 14 is started and stopped according to the operating state. Therefore, even if the engine 14 is stopped due to the engine stall, the driver cannot judge and the engine stall is prevented with a high possibility. As a result, the quality and reliability of the vehicle are improved.

Next, another embodiment of the present invention will be described. FIG. 10 is a flowchart corresponding to FIG. 8 and shows another mode of the engine stall prevention control in step SS6 in FIG. 7, and in step R2-1, a predetermined time (for example, one cycle in the flowchart in FIG. 7) is used. The change amount ΔNe of the engine rotation speed Ne is a predetermined value β
It is determined whether or not: The predetermined value β is for predicting that an engine stall will occur due to a decrease in the engine rotation speed Ne, and is a negative relatively large value generated when the engine rotation speed Ne suddenly decreases due to an excessive running load; That is, the amount of change hardly occurs in normal engine control, and may be set to a constant value in advance. A small value (close to 0) may be set. Step R2-1 functions as engine stall detection means for predicting engine stall based on a change in the rotation speed of the engine 14.

If the change amount .DELTA.Ne is equal to or smaller than the predetermined value .beta., It is determined that there is a high possibility that the engine will stall, 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.

FIG. 11 is a flow chart corresponding to FIG. 8 and shows still another mode of the engine stall prevention control in step SS6 in FIG.
At -1, it is determined whether or not the engine rotation speed Ne has become equal to or less than a predetermined lower limit Ne _min . Lower limit value Ne
_min is for predicting that an engine stall will occur due to a decrease in the rotation speed Ne, and is a value that occurs when the engine rotation speed Ne abnormally decreases due to an excessive running load, that is, almost no value in normal engine control. This is a rotation speed that does not occur, and is a constant value that is lower than the idling rotation speed _{Neidl of} the engine 14 and higher than the rotation speed at which the engine 14 misfires. This step R3
-1 functions as engine stall detection means for detecting whether there is a possibility of engine stall.

Then, when the engine speed Ne is lower than the lower limit N
If it becomes equal to or less than e _min , it is determined that the possibility of engine stall is high, and step R3-2 is executed. Step R
Reference numeral 3-2 functions as engine stall prevention means, which prevents engine stall in the same manner as in step R1-2 in FIG. In this case, the engine speed N
Since the possibility of engine stall is determined based on whether or not e has become equal to or less than the lower limit Ne _{min, the} determination of engine stall may be delayed as compared with the above-described embodiment. As a result, a decrease in driving force is suppressed.

FIG. 12 is a flowchart corresponding to FIG. 8 and shows still another mode of the engine stall prevention control in step SS6 in FIG.
−1, the steps R1-1, R2-1, or R
The possibility of engine stall is determined in the same manner as in 3-1. And if there is a possibility of engine stall,
In step R4-2, the control of the motor generator 16 is switched from the rotational speed control to the torque control, and the engine regenerative braking torque is controlled to a predetermined value to reduce the engine load. The torque value at this time is determined in consideration of the gear ratio ρ and the like so that the rotation speed Nm of the motor generator 16 changes depending on the running load, and is set to, for example, a value smaller by about one digit than the engine torque. As a result, the load on the engine 14 is reduced, the decrease in the engine speed Ne is suppressed, or the engine speed Ne is increased by itself to prevent a stall, and the same effects as those of the above embodiments can be obtained. Can be Step R4-1 functions as engine stall detection means, and step R4-2 functions as engine stall prevention means.

The torque control in step R4-2 is performed for one second or less, for example, about 300 msec in the same manner as in each of the above embodiments. In step R4-3, the control immediately returns to the rotation speed control and the target motor is controlled. Rotation speed Nm
^* Gradually change to the normal setting.

The vehicle drive control device shown in 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. They are connected, and power running control and regenerative control are performed. Also,
The rear wheel 96 is mechanically connected to the left and right rear wheels 96 via a differential device 94, and is rotationally driven by power running control, and a regenerative braking force is applied to the rear wheel 96 by regenerative control.

In such a vehicle drive control device, basically, the same control as in the above embodiments can be performed for the front-side hybrid drive control device 10. In this case, in the engine stall prevention control in step SS6 of FIG. 7, for example, as shown in the flowchart of FIG. 14, the assist control can be performed using the rear-side motor generator 90. That is, step R
In 5-1, the engine stall is predicted in the same manner as in the above-described embodiments. In step R5-2, the torque of the motor generator 16 is temporarily set to 0 to prevent the engine stall, while in step R5-3, The driving force of the rear-side motor generator 90 is made larger than usual, and the reduction of the driving force of the front-side hybrid drive control device 10 by performing the step R5-2 is assisted on the rear wheel 96 side. It is desirable that the amount of increase in the driving force by the rear-side motor generator 90 substantially coincides with, for example, the amount of decrease in the driving force due to the execution of step R5-2.
It may be increased by a predetermined fixed amount, and is appropriately set according to the torque capacity of the rear motor generator 90 and the like. Step R5-1 functions as engine stall detection means, and step R5-2 functions as engine stall prevention means.
5-3 functions as auxiliary driving means. In step R5-2, the torque of the motor generator 16 is temporarily set to 0. However, the torque may be reduced by a predetermined amount as in the above-described embodiments.

In this way, when the torque of motor generator 16 is reduced to 0 to prevent engine stall, rear wheel 9
Since the driving force of the vehicle 6 is increased, a decrease in the driving force when engine stall is prevented is reduced as a whole vehicle. Also,
Since the decrease in the driving force is reduced as described above, the time for temporarily turning off the motor torque in step R5-2 can be lengthened, and the time for returning from the drop in torque of the engine 14 can be sufficiently ensured. . That is, while suppressing the decrease in the driving force of the vehicle as a whole, step R5
The time at which the motor torque is reduced to 0 at -2 is continued for 1 second or more, so that the engine stall can be more reliably prevented.

The embodiments of the present invention have been described in detail with reference to the drawings. However, these embodiments are merely examples, and the present invention is based on the knowledge of those skilled in the art. Can be implemented.

[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 view 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;

FIG. 4 is a diagram for explaining a relationship between some traveling modes established in the hybrid drive control device of FIG. 1 and operating states of a clutch and a brake.

FIG. 5 is a collinear chart showing a relationship between rotation speeds of respective rotating elements of the planetary gear device in the ETC mode, the direct connection mode, and the motor traveling mode (forward) in FIG.

FIG. 6 shows a “motor drive mode” in the hybrid drive control device of FIG.
It is a flowchart explaining an example of the operation | movement which switches to "ETC mode" or "direct connection mode".

FIG. 7 shows an ET in the hybrid drive control device of FIG. 1;
It is a flowchart explaining operation | movement at the time of driving | running | working in C mode.

FIG. 8 is a flowchart illustrating specific contents of engine stall prevention control in step SS7 in FIG. 7;

FIG. 9 is a collinear diagram for explaining 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) illustrates engine stall prevention according to the flowchart of FIG. In the case where 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 the engine stall prevention control in step SS7 in FIG. 7;

FIG. 11 is a flowchart illustrating still another example of the engine stall prevention control in step SS7 in FIG. 7;

FIG. 12 is a flowchart illustrating still another example of the engine stall prevention control in step SS7 in FIG. 7;

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 illustrating an example of engine stall prevention control in the vehicle drive control device of FIG. 13, and is a diagram 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 (combined distribution device) 18s: Sun gear (first rotating element) 18c: Carrier (second rotating element) ) 1
8r: 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, R
5-1: Engine stall detecting means Steps R1-2, R2-2, R3-2, R4-2, R
5-2: Engine stall prevention means Step R5-3: Auxiliary drive means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyohiro Kamioka 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Automobile Co., Ltd. (72) Inventor Kyoji Kaji 1-1 1-1 Showacho, Kariya City, Aichi Prefecture DENSO Corporation F-term (reference) 3D039 AA03 AB27 AC21 3G093 AA07 BA05 CB02 DA06 DB11 EA02 EB01 EC01 FA11 FB02 5H115 PA01 PC06 PG04 PI16 PI24 PI29 PO02 PO06 PO09 PO17 PU22 PU23 PU24 PU25 PV09 QI04 QI09 QN03 QN06 SE03 TB03 RE03 TE02 TI01 TI05 TO21 TO30

Claims (8)

[Claims] 1. An engine which operates by combustion of fuel and an electric motor, wherein the electric motor outputs a reaction torque with respect to the output torque of the engine, thereby synthesizing the output torque of the engine and the electric motor. An engine stall detecting means for detecting whether there is a possibility of a stall due to a decrease in the rotational speed of the engine, and a stall enabled by the engine stall detecting means. An engine stall prevention means for reducing the torque applied to the engine by reducing the torque of the electric motor when it is determined that there is a possibility that the vehicle has a potential. 2. A gear type combination having a first rotating element connected to an engine operated by fuel combustion, a second rotating element connected to an electric motor, and a third rotating element outputting to driving wheels. A distributing device, wherein the first rotating element, the second rotating element, and the third rotating element are relatively rotatable, and the engine and the electric motor are operated together to operate the first rotating element and the second rotating element. An engine stall detecting means for detecting whether or not there is a possibility of a stall due to a decrease in the rotation speed of the engine, in a vehicle drive control device that travels by applying torque to a rotation element and rotating the third rotation element. When the engine stall detecting means determines that there is a possibility of a stall, an engine that reduces the torque of the electric motor to reduce the load acting on the engine. A drive control device for a vehicle, comprising: a gin stall prevention unit. 3. The vehicular drive control device according to claim 1, wherein the time during which the torque of the electric motor is reduced by the engine stall prevention means is 1 second or less. 4. An engine and an electric motor which operate by combustion of fuel, and a reaction torque is output by controlling a rotation speed of the electric motor with respect to an output torque of the engine, so that the engine and the electric motor A vehicle drive control device that combines output torque and outputs the combined output torque to a drive shaft, comprising: engine stall detection means for detecting whether there is a possibility that the engine speed decreases and stall; and engine stall detection means An engine stall prevention means for stopping the rotation speed control of the electric motor and reducing the load on the engine when it is determined that there is a possibility of a stall by the vehicle drive. Control device. 5. A gear type combination having a first rotating element connected to an engine operated by fuel combustion, a second rotating element connected to an electric motor, and a third rotating element outputting to driving wheels. A distributing device, wherein the first rotating element, the second rotating element, and the third rotating element are relatively rotatable, and the engine is operated to apply torque to the first rotating element; A drive control device for a vehicle that runs by rotating the third rotating element by controlling the rotation speed of the electric motor so that the two rotating elements have a predetermined rotating speed. Engine stall detecting means for detecting whether or not there is a possibility that the motor will stall. If the engine stall detecting means determines that there is a possibility of a stall, the rotational speed of the electric motor is determined. An engine stall prevention means for stopping the degree control to reduce the load on the engine. 6. The vehicle drive control according to claim 1, wherein the engine stall detection means predicts a stall based on a change in the rotation speed of the engine. apparatus. 7. A second drive wheel for driving one of a front wheel and a rear wheel of the vehicle, and driving the other of the front wheel and the rear wheel.
The drive control device for a vehicle according to any one of claims 1 to 6, further comprising: 8. The vehicle according to claim 7, further comprising auxiliary driving means for increasing a driving force of the second driving source when the load on the engine is reduced by the engine stall prevention means. Drive control device.