JPH1023604A - Controller for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent engine stalls in a hybrid vehicle, provided with an engine and an electric motor as power sources. SOLUTION: If the number of engine revolutions NE is equal to or smaller than a specified value Ee* and the amount of variation ΔNE is negative, that is, the judgments at steps SA2-SA4 are all 'YES' during drive using an engine as an power source, an electric motor is actuated to assist in torquing. Thus the load on the engine is reduced, and further the number of engine revolutions NE is forcedly increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle, and more particularly to a technique for preventing engine stall.

[0002]

2. Description of the Related Art A hybrid vehicle having an engine that operates by burning fuel and an electric motor that operates by electric energy as a power source when the vehicle runs is described in, for example, Japanese Patent Application Laid-Open No. 7-67208. I have. In such a hybrid vehicle, for example, by selectively using the engine and the electric motor in accordance with the driving state, the fuel consumption and the exhaust gas amount can be reduced while maintaining the predetermined running performance.

[0003]

However, in such a conventional hybrid vehicle, there is a possibility that an engine stall may occur for some reason during traveling using the engine as a power source. For example, if the shift lever is switched to the reverse range during forward running and the automatic transmission attempts to switch to the reverse gear, an excessive load may be applied to the engine and the engine may stall.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent engine stall in a hybrid vehicle having an engine and an electric motor as power sources. .

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a hybrid including an engine operated by fuel combustion and an electric motor operated by electric energy as a power source for running a vehicle. In the vehicle, (a) engine stall determining means for determining the possibility of engine stall when the engine is operating, and (b) the electric motor when the engine stall determining means determines that there is a possibility of engine stall. Motor stall prevention motor control means for reducing the load on the engine by a motor.

[0006]

In such a control device for a hybrid vehicle, the engine load is reduced by the electric motor when there is a possibility of engine stall, so that engine stall is prevented from occurring.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, the present invention relates to a switching type in which a power source is switched by connecting / disconnecting power transmission by, for example, a clutch, a combination of a planetary gear device, and the like.
The present invention can be applied to various types of hybrid vehicles including an engine and an electric motor as power sources for driving the vehicle, such as a mixed type in which outputs of an engine and an electric motor are combined or distributed by a distribution mechanism. It is also possible to provide an electric motor for each drive wheel.

The present invention relates to control when the engine is running and mainly when the vehicle is driven by the engine as a power source. The present invention is applied not only to the case where the vehicle runs only by the engine but also to the case where the vehicle runs using both the engine and the electric motor. The present invention can also be applied to a case where an electric motor is rotated while an engine is running to charge a power storage device. The present invention is also applicable to a case where the electric motor is rotated by the engine when the vehicle is stopped to charge the power storage device. It should be noted that other operation modes such as a motor operation mode in which only the electric motor is used as a power source, such as a motor operation mode, are performed depending on operation states such as an accelerator operation amount, a vehicle speed, and a state of charge (power storage state) of the power storage device. Is also good.

The engine stall determining means determines that there is a possibility of engine stall when the engine speed is equal to or less than a predetermined value and the change in the engine speed is negative during traveling using the engine as a power source, When there is a forward / reverse switching means (such as an automatic transmission) for switching forward / backward by friction engagement means according to a predetermined shift operation, there is a possibility of engine stall when a shift operation is performed to switch forward / backward at a predetermined vehicle speed or more. The determination is made based on various operating states such as the operating state of the engine, the accelerator operation amount, and the vehicle speed.

The motor stall prevention motor control means for reducing the load on the engine by the electric motor increases the motor torque of the electric motor when the vehicle is driven by the engine and the electric motor, for example. When the electric motor is rotating freely, a rotational torque is applied to the electric motor, and when the electric motor is performing charge control as a generator during traveling using only the engine as a power source, the motor torque (regenerative braking torque) is reduced. For example, it can be implemented in various modes depending on the operation state of the electric motor. When the engine and the electric motor are directly connected, the engine speed may be forcibly increased by the electric motor.

It is desirable to provide an engine stall-time motor control means for quickly switching to a running state in which only the electric motor is used as a power source when the engine is stalled. The vehicle can be started immediately without shifting to the P range or the like and restarting the engine.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a skeleton diagram of a hybrid drive device 10 of a hybrid vehicle including a control device according to one embodiment of the present invention. This hybrid drive 1
0 is for an FR (Front Engine / Rear Drive) vehicle, an engine 12 that operates by burning fuel,
A motor generator 14 used as an electric motor and a generator, and a single pinion type planetary gear set 16
And an automatic transmission 18 along the front-rear direction of the vehicle, and transmits power from the output shaft 19 to left and right driving wheels (rear wheels) via a propeller shaft, a differential device, and the like (not shown). Planetary gear set 16 is a synthetic distributing mechanism for mechanically synthesizing force distributor, constitutes an electric torque converter 24 together with the motor-generator 14, the ring gear 16r is connected to the engine 12 via the first clutch CE _1, The sun gear 16 s is a rotor shaft 14 of the motor generator 14.
r, the carrier 16c is connected to the input shaft 26 of the automatic transmission 18. Further, the sun gear 16s and the carrier 16c is adapted to be connected by the second clutch CE _2. The engine 12
Outputs are transmitted rotation fluctuation and the flywheel 28 and the spring for suppressing the torque variation, the first clutch CE ₁ via a damper device 30 by the elastic member such as rubber. First clutch CE ₁ and second clutch CE ₂
Are friction type multi-plate clutches, each of which is engaged and released by a hydraulic actuator.

The automatic transmission 18 is a front type overdry
An auxiliary transmission 20 composed of a bup planetary gear unit;
4 forward stages consisting of 3 purely connected planetary gear trains, rear
This is a combination with the first-speed main transmission 22. Ingredient
Physically, the auxiliary transmission 20 is a single pinion type planetary gear.
The vehicle device 32 is frictionally engaged with a hydraulic actuator.
Hydraulic clutch C₀ , Brake B₀ And on the other hand
Direction clutch F₀ It is comprised including. Main transmission 2
2, three sets of single pinion type planetary gear units 34,
36, 38 and frictionally engaged by a hydraulic actuator.
Hydraulic clutch C₁ , C_Two , Brake B₁ ,
B_Two , B_Three , B_Four And one-way clutch F ₁ , F_Two And
It is composed. Then, the sole shown in FIG.
Hydraulic pressure by energizing and de-energizing the solenoid valves SL1 to SL4
The circuit 44 is switched, or as a shift operation means.
A manual shift mechanically connected to the shift lever 40
The hydraulic circuit 44 is mechanically switched by the valve.
The clutch C as the engagement means.₀ , C
₁ , C_Two , Brake B₀ , B₁ , B_Two , B_Three , B_FourBut
The engagement and release are controlled respectively, as shown in FIG.
Neutral (N) and forward 5 steps (1st-5th), rear
The first shift stage (Rev) is established. In addition,
The automatic transmission 18 and the electric torque converter 24 are
It is configured substantially symmetrically with respect to the line, and in FIG.
The lower half is omitted.

In the clutch, brake, and one-way clutch columns of FIG. 3, "○" indicates engagement, and "●" indicates that the shift lever 40 is in the engine brake range, that is, "3", "2", or "L" range. Or "DM (Direct Mode)"
Engage when operated to the range, and the blank indicates non-engagement. In this case, the neutral N, the reverse gear Rev, and the engine brake range are established when the hydraulic circuit 44 is mechanically switched by a manual shift valve mechanically connected to the shift lever 40. When the gear is operated to the D (forward) range, the shifts between 1st to 5th and the presence or absence of the engine brake in the DM range are electrically controlled by the solenoid valves SL1 to SL4. The gear ratio of the forward gear is 5 to 1st (first gear).
As the speed becomes the th (fifth speed), the speed gradually decreases, and the 4th speed ratio i ₄ = 1 (direct connection). The gear ratio shown in FIG. 3 is an example.

As shown in FIG. 8, the shift lever 40 includes "P (parking)", "R (reverse)", "N (neutral)", "D (drive)", "DM (direct mode)", It is possible to operate to a total of nine operation ranges of "4", "3", "2", and "L", and corresponds to six operation positions located in the vertical direction (vehicle front-rear direction) in the figure. The manual shift valve is moved, and its six operating positions are detected by the shift position sensor 46. The "DM" range is a range in which the five forward gears (engine brake operation) can be manually switched, and the operation to the "DM" range is detected by the direct mode switch 41 (see FIG. 2). It has become. In the “DM” range, the shift lever 40 can be operated in the front-rear direction (vertical direction in the drawing), and the forward / backward operation of the shift lever 40 in the “DM” range is detected by the + switch 42 and the − switch 43. At the same time, the automatic transmission 18 is upshifted according to the number of times the + switch 42 is operated, and downshifted according to the number of times the-switch 43 is operated.

The hydraulic circuit 44 has a circuit shown in FIG. In FIG. 4, reference numeral 70 indicates a 1-2 shift valve, reference numeral 71 indicates a 2-3 shift valve, and reference numeral 72 indicates a 3-4 shift valve. The communication state of each port of these shift valves 70, 71, 72 at each shift speed is as shown below each shift valve 70, 71, 72. The numbers indicate the respective gears.

A third brake B ₃ is connected via an oil passage 75 to a brake port 74 communicating with the input port 73 in the first and second shift speeds among the ports of the 2-3 shift valve 71. . An orifice 76 is interposed in this oil passage, and the orifice 76 and the third brake B
₃ , a damper valve 77 is connected. The damper valve 77, the line pressure P in the third brake B ₃
When L is rapidly supplied, a small amount of hydraulic pressure is sucked to perform a buffering action.

The numeral 78 is a B-3 control valve, and controls the third engaging pressure of the brake B _3. That is, the B-3 control valve 78
Is provided with a spool 79, a plunger 80, and a spring 81 interposed therebetween, and an oil passage 75 is connected to an input port 82 opened and closed by the spool 79,
The output port 83 to be brought selectively communicating with the input port 82 is connected to the third brake B _3. Further, the output port 83 is connected to a feedback port 84 formed on the distal end side of the spool 79. On the other hand, among the ports of the 2-3 shift valve 71, a port 86 that outputs the D range pressure (line pressure PL) at the third or higher speed is included in the port 85 that opens at the position where the spring 81 is disposed. The connection is made through an oil passage 87. Further, a linear solenoid valve SLU is connected to a control port 88 formed on the end side of the plunger 80 so that the signal pressure P _SLU is applied.
Therefore, the B-3 control valve 78 has a pressure adjustment level set by the elastic force of the spring 81 and the hydraulic pressure supplied to the port 85, and the higher the signal pressure P _SLU supplied to the control port 88, the higher the spring 81. The elastic force is configured to be large.

Reference numeral 89 in FIG. 4 denotes a 2-3 timing valve.
Are disposed on the opposite side of the first plunger 91 with the spool 90 and the first plunger 91 having a small-diameter land and two large-diameter lands formed therebetween and the spring 92 and the spool 90 disposed therebetween. Second plunger 9
And 3. An oil passage 95 is connected to an intermediate port 94 of the 2-3 timing valve 89, and the oil passage 95 is connected to the brake port 74 at the third or higher speed among the ports of the 2-3 shift valve 71. It is connected to a port 96 to be communicated. The oil passage 95 branches off in the middle and is connected via an orifice to a port 97 opening between the small-diameter land and the large-diameter land, and a port 98 selectively communicated with the port 94 is an oil passage. 99
Through the solenoid relay valve 100. Then, a linear solenoid valve SLU is connected to a port opened at the end of the first plunger 91,
The second brake B ₂ is connected via an orifice to the port which is opened to the end of the second plunger 93.

[0020] The oil passage 87 is for the purpose of supplying and discharging the hydraulic pressure to the second brake B _2, a small diameter orifice 101 and a check ball with the orifice 102 is interposed in the midway. Further, the oil passage 103 branched from the oil passage 87, the large-diameter orifice 1 having a check ball to open when the pressure discharged from the second brake B ₂
The oil passage 103 is connected to an orifice control valve 105 described below.

The orifice control valve 105 is a valve for controlling the exhaust speed from the second brake B _2. The orifice control valve 105 has a second brake B at a port 107 formed at an intermediate portion so as to be opened and closed by a spool 106. _Two
The oil passage 103 is connected to a port 108 formed below the port 107 in the figure. A port 109 formed above the port 107 to which the second brake B ₂ is connected in the figure is a port selectively communicated with the drain port, and is connected to the port 109 via an oil passage 110. The port 111 of the B-3 control valve 78 is connected. Incidentally, this port 111 is a port that is not selectively communicating the output port 83 is connected to the third brake B _3.

A control port 112 formed at the end of the port of the orifice control valve 105 opposite to the spring for pressing the spool 106 is connected to a port 114 of the 3-4 shift valve 72 via an oil passage 113. ing. This port 114 outputs the signal pressure of the third solenoid valve SL3 at a speed lower than the third speed,
Further, it is a port for outputting a signal pressure of the fourth solenoid valve SL4 at a speed higher than the fourth speed. Further, the orifice control valve 105 is provided with the oil passage 9.
5 is connected to the oil passage 115, and the oil passage 115 is selectively connected to the drain port.

In the 2-3 shift valve 71, a port 116 for outputting a D-range pressure at a speed lower than the second speed is opened at a portion of the 2-3 timing valve 89 where a spring 92 is disposed. The port 117 is connected via an oil passage 118. A port 119 of the 3-4 shift valve 72 which is communicated with the oil passage 87 at a speed lower than the third speed is connected to the solenoid relay valve 100 via an oil passage 120.

Reference numeral 121 denotes an accumulator for the second brake B ₂ , and an accumulator control pressure P _ac regulated in accordance with a signal pressure P _SLN output from the linear solenoid valve SLN is supplied to the back pressure chamber. It has become. 2 → 3 when the 2-3 shift valve 71 is switched to the time shift, the second brake B ₂ oil passage 8
7, the D range pressure (line pressure PL) is supplied, and this line pressure PL causes the piston 121p of the accumulator 121 to start rising. This piston 12
While 1p is rising, the hydraulic pressure (engagement pressure) P _B2 supplied to the brake B ₂ balances the downward biasing force of the spring 121s and the accumulator control pressure P _ac which biases the piston 121 p downward. Substantially constant, strictly, the pressure is gradually increased with the compression deformation of the spring 121s, and when the piston 121p reaches the rising end, the line pressure P
It is raised to L. That is, the engagement pressure P _B2 at the time of shift transition in which the piston 121p moves is determined by the accumulator control pressure P _ac .

The accumulator control pressure P _ac is used to control the engagement of the second brake B ₂ when the third shift speed is established.
Although not shown, other than the accumulator 121 for
Gear position established when the clutch C ₁ for the accumulator to be engagement control, the clutch C ₂ is engagement control to the fourth gear position during establishment of the accumulator for the brake B ₀ which is engagement control to the fifth gear position holds, Also supplied to the accumulator,
The transient hydraulic pressure at the time of engagement / disengagement is controlled.

The reference numeral 122 in FIG. 4 shows a C-0 exhaust valve, further numerals 123 denotes an accumulator for the clutch C _0. C-0 exhaust valve 122 is to operate to engage the clutch C ₀ in order to engine brake only at the second gear of the second speed range.

According to such a hydraulic circuit 44, the shift from the second gear to the third gear, that is, the third brake B
In so-called clutch-to-clutch shifting engaging the second brake B ₂ as well as releasing the _3, third disengagement transition pressure and the second brake B ₂ engagement transition of the brake B ₃ and the like based on the input torque of the input shaft 26 By controlling the oil pressure, shift shock can be reduced appropriately. For other shifts, the transient hydraulic pressure of the clutches C ₁ and C ₂ and the brake B ₀ is controlled by adjusting the accumulator control pressure P _ac by the duty control of the linear solenoid valve SLN.

The hybrid drive device 10 includes a hybrid control controller 50 and an automatic transmission control controller 52 as shown in FIG. Each of these controllers 50 and 52 includes a microcomputer having a CPU, a RAM, a ROM, and the like, and includes an accelerator operation amount sensor 62, a vehicle speed sensor 63, an input shaft rotation speed sensor 64, and a pattern select switch 6.
5, the accelerator operation amount θ _AC , the vehicle speed V (corresponding to the rotation speed N _O of the output shaft 19 of the automatic transmission 18), the rotation speed N _I of the input shaft 26 of the automatic transmission 18, and a signal representing a selection pattern are supplied. another is, the engine torque T _E and the motor torque T _M, the engine speed N _E, the motor rotational speed N _M, the electricity storage amount SOC of the power storage device 58, ON the brake, OFF, information such as the operation range of the shift lever 40 is , And performs signal processing in accordance with a preset program. The accelerator operation amount θ _AC is an operation amount of the accelerator operation means 48 operated by the driver according to the output request amount, such as an accelerator pedal. The pattern select switch 65 is a pattern selecting means, and can select any one of a power pattern and a normal pattern for traveling with emphasis on power performance.
The engine torque T _E is determined from a throttle valve opening and the fuel injection amount, the motor torque T _M is determined from a motor current, the electricity storage amount SOC is Ya motor current during charging motor generator 14 functions as a generator Required from charging efficiency.

The output of the engine 12 is controlled in accordance with the operating state such as the accelerator operation amount θ _AC by controlling the throttle valve opening, fuel injection amount, ignition timing, and the like by the hybrid control controller 50. . As shown in FIG. 5, the motor generator 14 is connected to a power storage device 5 such as a battery via an M / G controller (inverter) 56.
8 and a rotational driving state in which electric energy is supplied from the power storage device 58 by the hybrid control controller 50 and is rotationally driven at a predetermined torque, and a regenerative braking (electric braking of the motor generator 14 itself). With the torque, the power storage device 58 is switched between a charging state in which the power storage device 58 is charged with electric energy and a no-load state in which the rotor shaft 14r is allowed to rotate freely. The first clutch CE ₁ and the second clutch CE ₂ are switched between the engaged and disengaged states by the hybrid controller 50 switching the hydraulic circuit 44 via an electromagnetic valve or the like. The automatic transmission 18 includes an automatic transmission control controller 5.
2 controls the excitation state of the solenoid valves SL1 to SL4 and the linear solenoid valves SLU, SLT, SLN, and switches the hydraulic circuit 44 or performs hydraulic control, thereby changing the operating state (for example, the accelerator operation amount θ _AC). And the vehicle speed V) is automatically switched according to a preset shift pattern. Two types of shift patterns are prepared corresponding to the power pattern and the normal pattern selected by the pattern select switch 65.

The hybrid control controller 50 includes:
For example, Japanese Patent Application No. 7-29414 filed earlier by the present applicant.
As described in No. 8, one of the nine operation modes shown in FIG. 7 is selected according to the flowchart shown in FIG. 6, and the engine 12 and the electric torque converter 24 are operated in the selected mode.

Referring to FIG. 6, in step S1, it is determined whether or not an engine start request has been issued, for example, to drive the engine 12 as a power source or to rotate the motor generator 14 by the engine 12 to charge the power storage device 58. It is determined whether there is a command to start the engine 12 or the like.
In mode 2, mode 9 is selected. Mode 9, the first clutch CE ₁ As apparent from FIG. 7 engaged (ON), the second clutch CE ₂ engaged (ON), the motor-generator 1
4, the engine 12 is rotated via the planetary gear unit 16, and the engine 12 is started by performing engine start control such as fuel injection. This mode 9, at the time of vehicle stop is performed by the automatic transmission 18 in neutral, only the motor-generator 14 first releases the clutch CE ₁ as mode 1 during running of the power source,
By engaging the first clutch CE ₁ and operating the motor generator 14 with an output higher than the required output required for traveling,
This is performed by rotationally driving the engine 12 with a margin output equal to or larger than the required output. Further, even when the vehicle is running, it is possible to temporarily execute the mode 9 with the automatic transmission 18 in the neutral state.

If the determination in step S1 is negative, that is, if there is no engine start request, step S3
By executing the above, whether or not there is a request for the braking force,
For example, whether the brake is ON or not, the operation range of the shift lever 40 is an engine brake range such as L or 2 or D.
In M range, and the accelerator operation amount theta _AC is 0 whether, or simply whether the accelerator operation amount theta _AC is 0, it is determined by such. If this determination is affirmed, step S4 is executed. In step S4, the storage amount SO of the power storage device 58
It is determined whether C is equal to or greater than a predetermined maximum charge amount B,
If SOC ≧ B, mode 8 is selected in step S5,
If SOC <B, mode 6 is selected in step S6. The maximum power storage amount B is the maximum power storage amount allowed to charge the power storage device 58 with electric energy.
For example, a value of about 80% is set based on the charge / discharge efficiency of No. 8 and the like.

Mode 8 selected in step S5
As shown in FIG. 7, the first clutch CE ₁ is engaged (ON), the second clutch CE ₂ is engaged (ON), the motor generator 14 is in a no-load state, and the engine 12
Is stopped, that is, the throttle valve is closed, and the fuel injection amount is set to 0, whereby the braking force due to the rubbing rotation of the engine 12 and the pump action, that is, the engine brake is applied to the vehicle, and the brake operation by the driver is performed. And the driving operation becomes easier. Further, since motor generator 14 is set in a no-load state and is freely rotated, it is possible to avoid a situation where power storage amount SOC of power storage device 58 becomes excessive and impairs performance such as charge / discharge efficiency.

[0034] Mode 6 is selected in step S6, disengaging the first clutch CE ₁ As apparent from FIG. 7 (OF
F), the second clutch CE ₂ is engaged (ON), the engine 12 is stopped, and the motor generator 14 is charged, and the motor generator 14 is rotationally driven by the kinetic energy of the vehicle. Since the power storage device 58 is charged and a regenerative braking force such as an engine brake is applied to the vehicle, the braking operation by the driver is reduced and the driving operation is facilitated. Further, since the first clutch CE ₁ is shut off is released the engine 12, since with no energy loss due to rotational resistance of the engine 12, the electricity storage amount SOC is executed when less than the maximum storage amount B, Power storage amount SOC of power storage device 58
Does not become excessive, thereby impairing performance such as charge and discharge efficiency.

If the determination in step S3 is denied, that is, if there is no request for the braking force, step S7 is executed to determine whether or not engine start is required, for example, by using the engine 12 as a power source in mode 3, for example. The determination is made based on whether or not the vehicle is stopped during running, that is, whether or not the vehicle speed V ≒ 0. If this determination is affirmed, it is determined in step S8 whether or not the accelerator is ON, that is, whether or not the accelerator operation amount θ _AC is larger than a predetermined value of substantially zero. Mode 5 is selected, and if the accelerator is not ON, mode 7 is selected in step S10.

Mode 5 selected in step S9
Is a first clutch CE ₁ As apparent from FIG. 7 engaged (ON), and second releasing clutch CE ₂ (OFF),
With the engine 12 in the operating state, the motor generator 14
The vehicle is started by controlling the regenerative braking torque of the vehicle. Specifically, the planetary gear device 1
_Assuming that the gear ratio of No. 6 is ρ _E , engine torque T _E : output torque of the planetary gear set 16: motor torque T _M = 1:
(1 + ρ _E ): Since it is ρ _E , for example, if the gear ratio ρ _E is about 0.5 which is a general value, the engine torque T
By half the torque of the _E motor generator 14 is shared, approximately 1.5 times the torque of the engine torque T _E is outputted from the carrier 16c. That is, a high torque start of (1 + ρ _E ) / ρ _E times the torque of motor generator 14 can be performed. Further, if the motor current is cut off and the motor generator 14 is put in a no-load state, the output from the carrier 16c becomes 0 just by rotating the rotor shaft 14r in the reverse direction, and the vehicle stops.
That is, the planetary gear device 16 in this case functions as a starting clutch and a torque amplifying device. By gradually increasing the motor torque (regenerative braking torque) T _M from 0 to increase the reaction force, the engine torque T _The vehicle can be started smoothly with an output torque of (1 + ρ _E ) times _E.

In this embodiment, a motor generator having a torque capacity approximately ρ _E times the maximum torque of the engine 12, that is, a motor generator 14 as small and small as possible while ensuring the required torque is used. ,
The device is compact and inexpensive. In this embodiment, the output of the engine 12 is increased by increasing the throttle valve opening and the fuel injection amount in response to the increase in the motor torque T _M. thereby preventing engine stall or the like due to the reduction in the number N _E.

The mode 7 selected in step S10 is
As can be appreciated the first clutch CE ₁ engages from FIG 7 (O
N), and second releasing clutch CE ₂ and (OFF), the engine 12 as a driving state, in which the electrically neutral motor-generator 14 as a no-load condition, the rotor shaft 14r is opposite direction of the motor-generator 14 , The output to the input shaft 26 of the automatic transmission 18 becomes zero. This allows
It is not necessary to stop the engine 12 one by one at the time of stopping the running vehicle using the engine 12 as a power source, such as in mode 3, and the engine can be started in mode 5 substantially.

If the determination in step S7 is negative, that is, if there is no request for starting the engine, step S1 is executed.
1 to determine whether the required output Pd is equal to or less than a first determination value P1 set in advance. The required output Pd is an output necessary for running the vehicle including the running resistance, and is the accelerator operation amount θ _AC
And the speed of change thereof, the vehicle speed V (the output rotational speed N _O ), the gear position of the automatic transmission 18, and the like, are calculated by a predetermined data map, an arithmetic expression, or the like. The first determination value P1 is a boundary value between a medium load region where the vehicle runs only using the engine 12 as a power source and a low load region where the vehicle runs only using the motor generator 14 as a power source. In consideration of the above, it is determined through experiments and the like that the amount of exhaust gas, fuel consumption, and the like are reduced as much as possible.

If the determination in step S11 is affirmative,
That is, when the required output Pd is equal to or less than the first determination value P1, it is determined in step S12 whether or not the state of charge SOC is equal to or greater than the preset minimum amount of charge A. If SOC ≧ A, the mode 1 is determined in step S13. On the other hand, if SOC <A, mode 3 is selected in step S14. The minimum power storage amount A is a minimum power storage amount that is allowed to take out electric energy from power storage device 58 when traveling using motor generator 14 as a power source, and is, for example, 70% based on charge / discharge efficiency of power storage device 58 and the like. The value of degree is set.

[0041] The mode 1, the 7 released as apparent the first clutch CE ₁ from to (OFF), the second clutch CE ₂ engaged (ON), to stop the engine 12,
The motor generator 14 is driven to rotate at the required output Pd, and the vehicle runs using only the motor generator 14 as a power source. In this case, since the engine 12 first clutch CE ₁ is released is interrupted, the mode 6 less similarly pulled rubbing losses, efficient motor drive by appropriate shift control of the automatic transmission 18 Control is possible. Further, this mode 1 is executed when the required output Pd is in the low load region where the first determination value P1 or less and the state of charge SOC of the power storage device 58 is equal to or more than the minimum state of charge A. The fuel efficiency and the exhaust gas can be reduced as compared with the case where the vehicle is traveling, and the state of charge SOC of the power storage device 58 is reduced to the minimum state of charge A.
The performance such as charge / discharge efficiency is not impaired.

Mode 3 selected in step S14 is
As is clear from FIG. 7, the first clutch CE ₁ and the second clutch CE ₁
The clutch CE ₂ is engaged (ON) together, the engine 12 is driven, the motor generator 14 is charged by regenerative braking, and is generated by the motor generator 14 while the vehicle is running at the output of the engine 12. Electric energy is charged in the power storage device 58. The engine 12 is operated at an output higher than the required output Pd, and the current control of the motor generator 14 is performed so that the motor generator 14 consumes a marginal power greater than the required output Pd.

If the determination in step S11 is negative,
That is, when the required output Pd is larger than the first determination value P1, in step S15, it is determined whether the required output Pd is larger than the first determination value P1 and smaller than the second determination value P2.
That is, it is determined whether or not P1 <Pd <P2. The second determination value P2 is determined by determining whether the engine 12 and the motor generator 14
Is a boundary value of a high load region in which the vehicle travels using both of the power sources as power sources. In consideration of energy efficiency including charging at the time of the engine 12, the exhaust gas amount, the fuel consumption amount, and the like are determined in advance by experiments and the like so as to minimize the amount of exhaust gas and fuel consumption. Stipulated.
If P1 <Pd <P2, step S16 is followed by step S16.
It is determined whether or not OC ≧ A. If SOC ≧ A, mode 2 is selected in step S17. If SOC <A, mode 3 is selected in step S14. Also, Pd ≧
If P2, it is determined in step S18 whether SOC ≧ A. If SOC ≧ A, mode 4 is selected in step S19, and if SOC <A, mode 2 is selected in step S17.

In the mode 2, the first clutch CE ₁ and the second clutch CE ₂ are both engaged (ON), the engine 12 is operated at the required output Pd, and the motor generator 14 is operated, as is apparent from FIG. Under no load condition, the vehicle is run using only the engine 12 as a power source. In addition, mode 4 includes the first clutch CE ₁ and the second clutch CE ₁ .
Clutch CE ₂ and together engaging (ON), the engine 12 and the operating state, in which to rotate the motor generator 14 to the high output running of the vehicle both engine 12 and motor-generator 14 as a power source. This mode 4 is executed in a high load region where the required output Pd is equal to or more than the second determination value P2. However, since the engine 12 and the motor generator 14 are used together, only one of the engine 12 and the motor generator 14 is used. Compared to running as a power source, energy efficiency is not significantly impaired, and fuel consumption and exhaust gas can be reduced. In addition, since the process is executed when the storage amount SOC is equal to or more than the minimum storage amount A, the storage amount SOC of the power storage device 58 does not decrease below the minimum storage amount A, and the performance such as charging and discharging efficiency is not impaired.

To summarize the operating conditions of modes 1 to 4, if the state of charge SOC ≧ A, in the low load region of Pd ≦ P1, mode 1 is selected in step S13 and the vehicle runs using only motor generator 14 as a power source. And P1 <P
In the medium load region of d <P2, mode 2 is selected in step S17, and the vehicle travels using only the engine 12 as a power source.
In the high load region of ≤Pd, mode 4 is selected in step S19, and the vehicle travels using both the engine 12 and the motor generator 14 as power sources. When SOC <A, the power storage device 58 is charged by executing the mode 3 of step S14 in the middle and low load region where the required output Pd is smaller than the second determination value P2. In the high load region equal to or greater than the determination value P2, mode 2 is selected in step S17, and high-power running is performed by the engine 12 without performing charging.

In mode 2 of step S17, P1 <Pd
<P2 in the middle load range and SOC ≧ A, or P
This is executed in the high load region where d ≧ P2 and when SOC <A.
Since the energy efficiency of the engine 12 is superior to that of the engine 12, the fuel consumption and exhaust gas can be reduced as compared with the case where the vehicle runs using the motor generator 14 as a power source. In a high load region, it is desirable to use Mode 4 in which the vehicle runs using both the motor generator 14 and the engine 12. However, when the state of charge SOC of the power storage device 58 is smaller than the minimum state of charge A, only the engine 12 in Mode 2 is used. Is performed, the power storage amount S of the power storage device 58 is stored.
It is avoided that the OC becomes smaller than the minimum charge amount A and the performance such as charge / discharge efficiency is impaired.

The hybrid control controller 50 also performs assist control by the motor generator 14 in accordance with the flowchart shown in FIG. 9 separately from the mode switching control. Of the series of signal processing by the hybrid control controller 50, steps SA3 and SA in FIG.
4 corresponds to engine stall determination means, and the step of executing step SA5 corresponds to engine stall prevention motor control means.

In step SA1 in FIG. 9, reading of various signals is performed.
In step SA2, the engine is running.
It is determined whether the mode is the mode (the mode 2). And d
In the engine running mode, the engine is started in step SA3.
Rotation speed N_EIs a predetermined value N_E ^*Whether or not
And at step SA4, the engine speed
N_EOf change ΔN_EIs negative, that is, engine rotation
Number N_EIs a downward trend, and both determinations are YES
If so, step SA5 is executed. Predetermined value N _E ^*Is an example
For example, a rotation speed higher than the idle rotation speed by a predetermined amount is set.
And the change amount ΔN_ERead for example one cycle ago
Engine speed N_E1And the current engine speed N_E2Difference with
(N_E2-N_E1).

At Step SA5, the motor generator
14 is operated to perform torque assist. In mode 2
Is the first clutch CE₁And second clutch CE_TwoIs
And the motor generator 14 and the engine
12 is in a directly connected state,
Is applied, the load on the engine 12 is increased.
And the engine speed N_EIs on
Can be raised. As a result, the stall of the engine 12 is reduced.
Is prevented. In this case, the motor generator 14
The strike torque may be a predetermined constant value,
Accelerator operation amount θ _ACAnd vehicle speed V, engine speed N_ESuch
The operating state of the
Number of turns N_EFeedback control so that the speed reaches a specified speed
It is also possible to do.

As described above, in this embodiment, when N _E ≦ N _E ^* and ΔN _E <0, it is determined that the possibility of engine stall is high, and torque assist is performed by the motor generator 14. and for that, an engine stall due to reduction in the engine rotational speed N _E due to overloading is prevented.

The hybrid control controller 50 further includes a motor control means at the time of engine stall.
By performing the signal processing according to the flowchart of FIG. 10, the vehicle runs using the motor generator 14 when the engine is stalled.

In step SB1 of FIG. 10, various signals are read, and in step SB2, it is determined whether or not the engine is in the engine running mode (mode 2). In the case of the engine running mode, it is determined in step SB3 whether or not the engine is stalled based on, for example, whether or not the engine speed N _E ≒ 0.
At B8, the fact that the engine is in the engine running mode is displayed on the instrument panel or the like. If the engine is stalled, steps SB4 and thereafter are executed.

In step SB4, it is determined whether or not the state of charge SOC of power storage device 58 is equal to or greater than the minimum state of charge A, that is, whether or not motor generator 14 can be used as a power source for running the vehicle. Step SB7 immediately
Is executed to display on the instrument panel or the like that the engine is stalled. YES in step SB4
, That is, if SOC ≧ A, step SB
In step 5, the mode is switched to the motor running mode (the mode 1), and the fact that the mode is the motor running mode is displayed on an instrument panel or the like.

As described above, when the engine is stalled, the mode can be promptly switched to the motor running mode. Therefore, in an emergency or the like, shifting to the N range, P range, or the like, and immediately restarting the engine 12 is not required. The vehicle can be started.

Next, an embodiment for preventing engine stall due to the D → R shift of the shift lever 40 will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. This is executed by the hybrid control controller 50, of which the part executing steps SC2 and SC3 corresponds to engine stall determination means, and the part executing steps SC5 and SC8 corresponds to engine stall prevention motor control means.

In step SC1 of FIG. 11, various signals are read, and in step SC2, it is determined whether or not the shift lever 40 has been switched from the D range to the R range within a relatively short predetermined time by a shift position sensor. 4
In addition to the determination based on the signal from the control unit 6 and the like, it is determined in step SC3 whether the vehicle speed V is equal to or higher than a predetermined vehicle speed V ^* . The predetermined vehicle speed V ^* is set on the basis of whether or not an excessive load is applied to the engine 12 to cause engine stall when the automatic transmission 18 is switched from the forward gear to the reverse gear with the D → R shift. For example, 5
A vehicle speed of about 10 km / h is determined.

If the determinations in steps SC2 and SC3 are both YES, that is, D → R shift and V ≧ V
^In the case of ^* , it is determined whether or not the engine is in the engine running mode (the mode 2) in step SC4. If the engine is in the engine running mode, the motor generator 14 is operated in step SC5 to perform torque assist. In mode 2, the first clutch CE ₁ and the second clutch CE ₂ are both engaged, the motor generator 14 and the engine 12 is in a directly coupled state, the motor generator 14 by a positive torque is applied, the engine 12 The load is reduced, and the stall of the engine 12 is prevented.

If the determination in step SC4 is NO,
That is, if the mode is not the engine drive mode, step SC
6 to determine whether or not the motor drive mode (mode 1)
If in the motor running mode, the motor
Torque T_MTo rise. In the motor drive mode,
In other words, the engine + motor drive mode (
Mode 4), the motor torque T is determined in step SC8.
_MTo rise. Motor drive mode, engine + motor
The driving mode is a motor generator
, The motor generator 14
Motor torque T _MI just want to upload.

Note that in steps SC5 and SC8 described above.
The assist torque of the motor generator 14 is predetermined.
May be a fixed value, but the vehicle speed V and engine speed
Number N _ESuch as operating conditions as parameters,
Engine speed N_EFeed so that the speed
It is also possible to perform back control.

As described above, in this embodiment, when the shift is D → R and V ≧ V ^* , it is determined that the possibility of engine stall is high, and the torque assist is performed by the motor generator 14 (steps SC5 and SC8). ), The engine stall due to overload is prevented beforehand. In particular, in this embodiment as compared with the case of performing to begin torque assist by the motor generator 14 at the stage of D → R shift actually torque assist from the engine speed N _E is reduced as in the first embodiment It has excellent responsiveness and can more reliably prevent engine stall. That, D → hydraulic circuit 44 is switched by a R-shift, reverse gear hydraulic clutch C ₂ is increased (Rev)
Is established, there is a slight time delay from the D → R shift to the increase of the C ₂ oil pressure (clutch engagement force),
Clutch C for torque assist of motor generator 14
_This can be done in response to the increase in hydraulic pressure in ₂ .

Although the above example describes the case of the D → R shift, the same control can be performed in the case of the R → D shift.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be embodied in other forms.

For example, in the above-described embodiment, the automatic transmission 18 having one reverse speed and five forward speeds was used. However, as shown in FIG. It is also possible to adopt an automatic transmission 60 consisting of only the second gear 22 and perform the shift control at four forward speeds and one reverse speed as shown in FIG.

Although not specifically exemplified, the present invention can be embodied with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram illustrating a configuration of a hybrid drive device of a hybrid vehicle including a control device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a control system included in the hybrid drive device of FIG.

FIG. 3 is a diagram illustrating the operation of an engagement element that establishes each shift speed of the automatic transmission of FIG. 1;

FIG. 4 is a diagram showing a part of a hydraulic circuit provided in the automatic transmission of FIG. 1;

FIG. 5 is a diagram illustrating a connection relationship between the hybrid control controller of FIG. 2 and an electric torque converter.

FIG. 6 is a flowchart illustrating a basic operation of the hybrid drive device of FIG. 1;

FIG. 7 shows each mode 1 to 9 in the flowchart of FIG.
It is a figure explaining the operation state of.

FIG. 8 is a diagram illustrating an example of an operation pattern of a shift lever.

FIG. 9 is a flowchart illustrating a main part of a control operation which is a feature of an embodiment to which the present invention is applied.

FIG. 10 is a flowchart illustrating an operation when an engine stall occurs.

FIG. 11 is a flowchart illustrating another embodiment of the present invention.

FIG. 12 is a skeleton diagram illustrating another example of a hybrid drive device of a hybrid vehicle to which the present invention is suitably applied.

13 is a diagram illustrating the operation of an engagement element that establishes each shift speed of the automatic transmission in FIG.

[Explanation of symbols]

12: Engine 14: Motor generator (electric motor) 50: Controller for hybrid control Steps SA3 to SA4, SC2 to SC3: Engine stall determination means Steps SA5, SC5, SC8: Engine stall prevention motor control means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yushi Hata 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Tsuyoshi Mika 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (1)

[Claims] 1. In a hybrid vehicle including an engine that operates by burning fuel and an electric motor that operates by electric energy as a power source when the vehicle is running, a possibility of engine stall is determined when the engine is operating. An engine stall determining unit; and an engine stall prevention motor control unit configured to reduce a load on the engine by the electric motor when the engine stall determining unit determines that there is a possibility of engine stall. Hybrid vehicle control device.