JP3536538B2 - Hybrid vehicle control device - Google Patents

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 equipped with an engine operating by burning fuel and an electric motor operating by electric energy as a power source for running the vehicle 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 depending on the driving state, the fuel consumption and the exhaust gas amount can be reduced while maintaining the predetermined traveling 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 speed, an excessive load is applied to the engine, and the engine may stall.

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

[0005]

According to a first aspect of the present invention, there is provided an engine operated by combustion of fuel and an electric motor operated by electric energy as a power source for driving a vehicle. In the hybrid vehicle, (a) when the engine operates, the engine speed N _E
And an engine stall determining means for determining the likelihood of engine <br/> installation based on a change amount .DELTA.N _E of the engine speed, it is determined that there is a possibility of the engine stall by (b) the engine stall determining unit In this case, there is provided an engine stall prevention motor control means for reducing a load on the engine by the electric motor. A second invention is directed to a hybrid vehicle control system according to the first invention.
In the control device, the engine stall determining means
During operation of the serial engine, the engine rotational speed N _E is predetermined
Value N _E ^* or less and a change amount ΔN _{E of the} engine speed.
Is negative, it is determined that there is a possibility of engine stall.
It is characterized by that. The third invention is based on the combustion of fuel
An engine that works and an electric motor that works with electrical energy
And a power source for driving the vehicle.
In head vehicle, (a) the engine and the electric motor
Before switching back and forth between the motor and drive wheels
Reverse drive switching means, and (b) a vehicle powered by the engine
Forward / reverse switching by the forward / reverse switching means during both traveling
To determine the possibility of engine stall
Engine stall determination means, and (c) the engine stall
It is determined that there is a possibility of engine stall
If the power is cut off, the electric motor
Stall prevention motor control means for reducing load on vehicle
And characterized in that: The fourth invention is the third invention.
In the control device for a hybrid vehicle, the engine
When the vehicle speed V is equal to or higher than a predetermined value V ^* ,
When the forward / reverse switching is performed by
Characterized by the possibility of gin stalls
You. The fifth invention is directed to the hive according to any one of the first invention to the fourth invention.
In the control device for a lid vehicle, the engine and the front
The output of the electric motor is synthesized and distributed via a planetary gear unit.
It is characterized by being performed.

[0006]

In such a hybrid vehicle control apparatus, 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. That is, the first invention
Then, change of the engine speed _NE and the engine speed
Based on the amount ΔN _E , for example, N _E ≦ N as in the second invention.
Engine stall possible when _E ^* and ΔN _E <0
The engine load with the electric motor.
To reduce, decrease in the engine rotational speed N _E by overload
The engine stall caused by the above is prevented. Also,
In the third invention, the forward / reverse switching is performed by the forward / reverse switching means.
When possible, determine the possibility of engine stall and
If there is a possibility of gin stall,
Engine load due to overload to reduce engine load.
Is prevented beforehand. In the fourth invention, V ≧ V ^* before and after
The possibility of engine stall when
Judging that there is, reduce the load on the engine with the electric motor
Engine after the engine speed has actually dropped.
Better response than when reducing the load on the
Jin stall can be more reliably prevented.

[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 running the vehicle, such as a mixed type in which the outputs of the engine and the 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, mainly when the vehicle is driven by the engine as a power source. The present invention relates 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 the electric motor is rotated while the engine is running to charge the 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, are performed depending on operation states such as an accelerator operation amount, a vehicle speed, and a state of charge (power storage state) SOC of the power storage device. Is also good.

The engine stall determining means determines that there is a possibility of an 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, for example. When there is a forward / reverse switching means (such as an automatic transmission) for switching between forward and reverse by friction engagement means in accordance with a predetermined shift operation, there is a possibility of engine stall when the shift operation is performed to switch forward and backward at a predetermined vehicle speed or higher. 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 given 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
Numeral 0 is for an FR (front engine / rear drive) vehicle, and includes 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 drive 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 16s is a rotor shaft 14 of the motor generator 14.
r, the carrier 16 c 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 has a front-end 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.
Frictionally engaged with the vehicle device 32 by the 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 used 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 FIG. 3, "O" in the column of clutch, brake and one-way clutch 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 shift speed 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 shift 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 in 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 front-back 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 denotes a 1-2 shift valve, reference numeral 71 denotes a 2-3 shift valve, and reference numeral 72 denotes a 3-4 shift valve. The communication state of each port of the shift valves 70, 71, 72 at each shift speed is as shown below each shift valve 70, 71, 72. In addition, the number shows each shift stage.

A third brake B ₃ is connected via an oil passage 75 to a brake port 74 communicating with the input port 73 at the first shift speed and the second shift speed 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. 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, the 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 a signal pressure P _SLU is applied.
Therefore, the B-3 control valve 78 sets the pressure regulation level 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 across the spool 90 and the first plunger 91 having a small-diameter land and two large-diameter lands, 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 an 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 the 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. Further, 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 according to a signal pressure P _SLN output from the linear solenoid valve SLN is supplied to a back pressure chamber thereof. 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 121p 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 applied to the second brake B ₂ which is controlled to be engaged 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 hydraulic 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.

As shown in FIG. 2, the hybrid drive device 10 includes a controller 50 for hybrid control and a controller 52 for automatic shift control. Each of these controllers 50 and 52 includes a microcomputer having a CPU, a RAM, a ROM, etc., and includes an accelerator operation amount sensor 62, a vehicle speed sensor 63, an input shaft rotation speed sensor 64, 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 according to 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 selection means, and can select any one of a power pattern for performing traveling with emphasis on power performance and a normal pattern.
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 operation 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.
And a rotational driving state in which electric energy is supplied from the power storage device 58 by the hybrid control controller 50 to rotate the motor generator 14 at a predetermined torque, and a regenerative braking (electric braking of the motor generator 14 itself). The state is switched between a charging state in which the power storage device 58 is charged with electric energy by functioning as a generator by a torque) 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 in accordance with 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.

In FIG. 6, in step S1, it is determined whether or not an engine start request has been issued, for example, to run the vehicle using 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 greater 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 neutral.

If the determination in step S1 is negative, that is, if there is no engine start request, step S3
By executing, 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.
The determination is made based on whether or not the accelerator operation amount θ _AC is in the M range and the accelerator operation amount θ _AC is 0, or the like. 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 or not 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 charging / discharging efficiency of No. 8.

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 driver performs the brake operation. And the driving operation is facilitated. In addition, since motor generator 14 is set in a no-load state and is freely rotated, it is possible to prevent the state of charge and discharge efficiency and the like from being impaired due to excessive power storage amount SOC of power storage device 58.

[0034] Mode 6 is selected in step S6, disengaging the first clutch CE ₁ As apparent from FIG. 7 (OF
F), and a second clutch CE ₂ engaged (ON), to stop the engine 12, in which the motor generator 14 and the charging state, the motor generator 14 in the kinetic energy of the vehicle is rotated, 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 released and the engine 12 is shut off, there is no energy loss due to the rotational resistance of the engine 12 and the operation is performed when the state of charge SOC is smaller than the maximum state of charge B. Power storage amount SOC of power storage device 58
Does not become excessive, thereby impairing the performance such as charge and discharge efficiency.

If the determination in step S3 is denied, that is, if there is no request for braking force, step S7 is executed to determine whether engine start is required, for example, by using the engine 12 as a power source in mode 3, for example. It is determined whether or not the vehicle is stopped during running, that is, whether or not the vehicle speed V ≒ 0. If this determination is affirmative, 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 , if the gear ratio ρ _{E is set} to a general value of about 0.5, for example, 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 set in the no-load state, the output from the carrier 16c becomes 0 only 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. The engine torque T _M is increased by gradually increasing the motor torque (regenerative braking torque) T _M from 0 to increase the reaction force. _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 small 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.

Mode 7 selected in step S10 is as follows.
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 when the vehicle is stopped 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 (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 with the engine 12 as a power source and a low load region where the vehicle runs only with the motor generator 14 as a power source. In consideration of the above, it has been determined through experiments and the like that the amount of exhaust gas and the amount of fuel consumption are minimized.

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 the minimum state of charge A or more. 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 charging / discharging 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 generated by the motor generator 14 while the vehicle is running at the output of the engine 12. Electric energy is charged into 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, it is determined in step S15 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 based on the medium load region where the vehicle runs only using the engine 12 as a power source, the engine 12 and the motor generator 14
Is a boundary value of a high-load region where the vehicle travels using both as power sources. In consideration of energy efficiency including charging at the time of the engine 12, exhaust gas amount, 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, and 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 runs using only the engine 12 as a power source. Further, the 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 larger 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 traveling 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 state of charge SOC is equal to or more than the minimum state of charge A, the state of charge SOC of the power storage device 58 does not drop below the minimum state of charge A and does not impair the performance such as charge and discharge efficiency.

To summarize the operating conditions of the modes 1 to 4, if the state of charge SOC ≧ A, in the low load region of Pd ≦ P1, the mode 1 is selected in step S13 and the vehicle runs using only the 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 a 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 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 the 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, mode 4 in which the motor generator 14 and the engine 12 are used together is desirable. 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 performs the 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
Is determined, and the engine speed is determined in step SA4.
N_EChange amount ΔN_EIs negative, that is, engine rotation
Number N_EIs a downward trend, and all the 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 of 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
Setting 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, the process from step SB4 is 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 minimum amount 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 above-described 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, the engine 12 is quickly shifted to the N range or the P range without restarting the engine 12. 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.
1 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,
In other words, if it is not the engine drive mode, step SC
6 to determine whether or not the motor drive mode (mode 1)
If the mode is 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
14, 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.
The vehicle speed V and engine speed
Number N _ESuch as operating conditions as parameters,
Engine speed N_EFeed so that the speed is
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). ), Engine stall due to overload is prevented. 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 .

In the above example, the case of the D → R shift has been described. However, 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 implemented in various modified and improved modes 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;

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) 18: Automatic transmission (forward / backward switching means) 50: Hybrid control controller steps SA3 to SA4, SC2 to SC3: Engine stall determining means Steps SA5, SC5, SC8: Engine stall Prevention motor control means

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI B60K 6/04 530 B60K 6/04 530 733 733 F02D 29/02 F02D 29/02 D (72) Inventor Yuji Hata Toyota City, Aichi Prefecture No. 1, Toyota Town, Toyota Motor Co., Ltd. (72) Inventor Tsuyoshi Mikami 1, Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (56) References JP-A-2-256843 (JP, A) Hei 8-99564 (JP, A) JP-A-5-79365 (JP, A) JP-A 5-1588 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 6 / 02-6/04 B60L 11/00-11/18 F02D 29/00-29/06

Claims (5)

(57) [Claims] And 1. A engines operating by combustion of fuel, in a hybrid vehicle and an electric motor as a power source while the vehicle is running to operate in electrical energy, during operation of the engine, the engine speed N _E and ET
An engine stall determining means for determining the possibility of the engine stall on the basis of the engine rotation speed variation amount .DELTA.N _E, if it is determined that there is a possibility of engine stalling by the engine stall determining unit, wherein the electric motor A control device for a hybrid vehicle, comprising: an engine stall prevention motor control unit that reduces an engine load. 2. The engine stall determining means,
When the engine is running, the engine speed N _E Is a predetermined value
N _E ^* And the variation ΔN of the engine speed _E But
Judging that there is a possibility of engine stall when negative
The hybrid vehicle according to claim 1, wherein
Control device. 3. An engine that operates by burning fuel.
And an electric motor operated by electric energy
Hybrid vehicle equipped as a power source at the time
hand, Arranged between the engine and the electric motor and the drive wheels.
Forward and backward switching means for switching between forward and backward When the vehicle is powered by the engine,
When switching between forward and reverse by the switching means, the engine
Engine stall determining means for determining the possibility of stall
When, The engine stall is determined by the engine stall determining means.
When it is determined that there is a possibility of
Therefore, an engine stall that reduces the load on the engine
Hive having anti-motor control means
Control device for lid vehicle. 4. The vehicle according to claim 1, wherein said engine stall determining means determines a vehicle speed.
V is a predetermined value V ^* As described above, the forward / reverse switching means
The possibility of engine stall when
4. The high according to claim 3, wherein it is determined that there is
Control device for brid vehicle. 5. The engine and the electric motor are idle.
The output is combined and distributed via a star gear device
The hybrid according to any one of claims 1 to 4,
Vehicle control device.