JPH1089115A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fuel consumption efficiency by increasing the frequency of lean burn running during the running of a vehicle in a hybrid vehicle which is provided with an engine and an electric motor as an power source used for the running of the vehicle, and has an engine control means which facilitates the lean burn running where the engine is actuated at an air-fuel ratio larger than a theoretical air-fuel ratio. SOLUTION: In the case where a vehicle is judged to be in the course of lean burn running(step SA2), since torque assistance for the lean burn running larger than in the case of normal running is carried out by an electric motor(step SA5), the shortage of torque becomes difficult to happen even at the time of the lean burn running, and frequency at which the engine is actuated near the theoretical air-fuel ratio and run in order to avoid the shortage of torque due to the lean burn running can be controlled lower, and fuel consumption efficiency can therefore be further improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a hybrid vehicle, and more particularly to control during a lean burn operation in which an engine is operated at an air-fuel ratio larger than a stoichiometric air-fuel ratio.

[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. According to such a hybrid vehicle, predetermined power performance can be obtained while reducing fuel consumption and exhaust gas amount by using the engine and the electric motor selectively.

On the other hand, it is widely known that a normal engine vehicle has an engine control means capable of performing a lean burn operation for operating the engine at an air-fuel ratio larger than the stoichiometric air-fuel ratio.

[0004]

However, lean burn operation has a problem that fuel efficiency is improved, but there is a problem that a torque shortage is apt to occur. Even though the efficiency was slightly reduced, the lean burn operation had to be stopped and the engine had to be temporarily operated near the stoichiometric air-fuel ratio to run.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an engine and an electric motor as power sources for driving a vehicle, which is larger than a stoichiometric air-fuel ratio. An object of the present invention is to improve the fuel efficiency by increasing the frequency of use of lean burn operation in a hybrid vehicle having an engine control means capable of lean burn operation in which an engine is operated at an air-fuel ratio.

[0006]

In order to achieve the above object, a first aspect of the present invention is to provide (a) an engine operated by fuel combustion and an electric motor operated by electric energy as power sources for running a vehicle. A control apparatus for a hybrid vehicle, comprising: (b) engine control means capable of normal operation for operating the engine at a stoichiometric air-fuel ratio and lean-burn operation for operating the engine at an air-fuel ratio larger than the stoichiometric air-fuel ratio Wherein (c) assist control means for performing greater torque assist by the electric motor during the lean burn operation than during the normal operation.

The second invention comprises (a) an engine which operates by burning fuel and an electric motor which operates by electric energy as a power source for running the vehicle, while (b) a predetermined lean burn system. When the condition is satisfied, in the control device for a hybrid vehicle having engine control means for performing lean burn operation for operating the engine at an air-fuel ratio larger than the stoichiometric air-fuel ratio, (c) the hybrid vehicle control device may satisfy the lean burn condition. It is characterized by having assist control means for performing torque assist by an electric motor.

[0008]

According to the first aspect of the present invention, a large torque assist is performed by the electric motor during the lean burn operation as compared with the normal operation, so that the shortage of the torque hardly occurs even during the lean burn operation, and the torque due to the lean burn operation is reduced. In order to avoid the shortage, it is possible to suppress the frequency of running the engine near the stoichiometric air-fuel ratio, thereby further improving the fuel efficiency.

According to the second aspect, torque assist is performed by the electric motor so as to satisfy the lean burn condition as much as possible, so that the current running state can easily satisfy the lean burn condition. As a result, the frequency of running the vehicle with the engine operated can be reduced, so that the fuel efficiency can be further improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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, and a combination of a planetary gear unit and the like, and an output of an engine and an electric motor by a distribution mechanism. And various types of hybrid vehicles including an engine and an electric motor as power sources for running the vehicle, such as a mixed type that synthesizes and distributes the same.

Further, in the control device according to the first aspect, the electric motor performs larger torque assist during the lean burn operation than during the normal operation. If it is equal to or less than the predetermined value, the throttle valve opening with respect to the accelerator operation amount is increased by a predetermined amount, or the shift line of the shift map, which is set in advance with the vehicle speed and the accelerator operation amount as parameters, is set to the lower gear range. Is desirably configured so as to suppress the torque shortage during the lean burn operation by changing so as to increase.

In the control device according to the present invention, the electric motor is configured to execute the torque assist so as to satisfy the lean burn condition. However, the electric storage device supplies electric power to the electric motor. Is smaller than or equal to a predetermined value, it is desirable to perform normal operation of operating the engine at the stoichiometric air-fuel ratio.

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.

In FIG. 1, a hybrid drive unit 10 is for an FR (front engine / rear drive) vehicle, and includes an engine 12 such as an internal combustion engine which operates by burning fuel and an electric motor which operates by electric energy. A motor generator 14, a single pinion type planetary gear set 16, and an automatic transmission 18 are provided along the front-rear direction of the vehicle, and the left and right are output from an output shaft 19 via a propeller shaft (not shown) or a differential device. The driving force is transmitted to the driving wheels (rear wheels).

The planetary gear unit 16 is a composite distribution mechanism for mechanically distributing and distributing force. The planetary gear unit 16 constitutes an electric torque converter 24 together with the motor generator 14, and its ring gear 16.
r is connected to the engine 12 via the first clutch CE _1, sun gear 16s is connected to the rotor shaft 14r of the motor generator 14, the carrier 16c automatic transmission 18
Are connected to the input shaft 26. Sun gear 16s
And carrier 16c is adapted to be connected by the second clutch CE _2.

[0016] The output of the engine 12 is 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. Each of the first clutch CE ₁ and the second clutch CE ₂ is a friction type multi-plate clutch that is engaged and released by a hydraulic actuator.

The automatic transmission 18 is a combination of an auxiliary transmission 20 composed of a front type overdrive planetary gear unit and a main transmission 22 having four forward stages and one reverse stage composed of a simple connection of three planetary gear trains. .

More specifically, the auxiliary transmission 20 is a single pini
ON type planetary gear set 32 and hydraulic actuator
Hydraulic clutch C frictionally engaged₀ , Bray
Key B ₀ And one-way clutch F₀ And is configured with
You. The main transmission 22 has three sets of single pinion type.
Planetary gear units 34, 36, 38, and hydraulic actuator
Hydraulic clutch C frictionally engaged by₁ ,
C_Two , Brake B₁ , B_Two , B_Three , B_Four And a one-way club
Switch F₁ , F_Two It is comprised including.

The hydraulic circuit 44 is energized and de-energized by the solenoid valves SL1 to SL4 shown in FIG.
Is switched, or the hydraulic circuit 44 is mechanically switched by a manual shift valve connected to the shift lever, whereby the clutches C ₀ , C ₁ , C
_{2. The} brakes B ₀ , B ₁ , B ₂ , B ₃ , and B ₄ are engaged and released, respectively, to control the neutral (N), the forward five steps (1st to 5th), and the reverse as shown in FIG. Each shift speed of one speed (Rev) is established.

The automatic transmission 18 and the electric torque converter 24 are configured substantially symmetrically with respect to the center line, and the lower half of the center line is omitted in FIG.

In the clutch, brake, and one-way clutch columns of FIG. 3, "O" indicates engagement, and "●" indicates that the shift lever is in the engine brake range, such as the "3", "2", and "L" ranges. Engage when operated to low speed range,
A 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 a shift lever. The shifts between the first to fifth gears are electrically controlled by solenoid valves SL1 to SL4.

The gear ratio of the forward gear is 5 from 1st.
and the speed ratio i _{4 of the} 4th is 1 and the speed ratio i ₅ of the _5th is smaller than the auxiliary transmission 2
Assuming that the gear ratio of the planetary gear device 32 of 0 is ρ (= the number of teeth of the sun gear Z _S / the number of teeth of the ring gear Z _R <1), 1 / (1+
ρ). Gear ratio i _R of the reverse speed Rev, respectively [rho ₂ the gear ratio of the planetary gear 36 and 38, a 1-1 / ρ ₂ · ρ ₃ When [rho _3. FIG. 3 shows an example of the gear ratio of each gear.

As shown in the operation table of FIG.
Shifting between the gear stage (2nd) and third shift stage (3rd) will clutch-changing the engagement-released state of the second brake B ₂ and the third brake B ₃ together.
The circuit shown in FIG. 4 is incorporated in the above-described hydraulic circuit 44 in order to smoothly perform this shift.

In FIG. 4, reference numeral 70 indicates a 1-2 shift valve, and reference numeral 71 indicates a 2-3 shift valve.
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 determined by the respective shift valves 70, 7
1 and 72 are shown below. The numbers indicate the respective gears.

The third brake B ₃ is connected to an oil passage 7 through 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.
5 are connected. This oil passage has an orifice 7
6 is interposed, the damper valve 77 is connected between the orifice 76 and the third brake B _3.
The damper valve 77 is configured to perform a buffering action by inhalation of a small amount of hydraulic pressure when the line pressure to the third brake B ₃ is rapidly supplied.

Further numeral 78 B3 control a valve, the engagement pressure P _B3 of the third brake B ₃ The B3
It is directly controlled by the control valve 78. That is, the B-3 control valve 7
8 includes 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, and the input port 82 is selectively connected to the oil path 75. output port 83 which is communicated with 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 for outputting the D range pressure at the third or higher speed is an oil passage. It is communicated via 87. Further, a linear solenoid valve SLU is connected to a control port 88 formed on the end side of the plunger 80.

Therefore, the B-3 control valve 7
8 is configured such that the pressure adjustment level is set by the elastic force of the spring 81 and the hydraulic pressure supplied to the port 85, and the elastic force of the spring 81 increases as the signal pressure supplied to the control port 88 increases. ing.

Further, reference numeral 89 in FIG.
The 2-3 timing valve 89 includes a spool 90 having a small-diameter land and two large-diameter lands, a first plunger 91, and a spring 92 and a spool 90 disposed therebetween. First
And a second plunger 93 disposed on the opposite side to the plunger 91 of the second embodiment.

An oil passage 95 is connected to a port 94 at an intermediate portion of the 2-3 timing valve 89.
Reference numeral 5 denotes a port of the 2-3 shift valve 71 which is connected to a port 96 which is communicated with the brake port 74 at the third or higher speed.

Further, the oil passage 95 branches on the way.
Port 9 opening between the small land and the large land
7 is connected via an orifice. A port 98 selectively connected to the intermediate port 94 is connected to a solenoid relay valve 100 via an oil passage 99.

[0033] Then, the linear solenoid valve SLU is connected to the port that is open to an end portion of the first plunger 91, also the second brake B ₂ is an orifice to a port that opens to the end of the second plunger 93 Connected through.

[0034] 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圧速degree from the second brake B _2, the port 107 formed in an intermediate portion to be opened and closed by the spool 106 and the second brake B _Two
The oil passage 103 is connected to a port 108 formed below the port 107 in the figure.

Port 1 to which the second brake B ₂ is connected
The port 109 formed on the upper side in FIG. 7 is a port selectively communicated with the drain port. The port 109 is connected to the port 111 of the B-3 control valve 78 via an oil passage 110. It 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, an oil passage 115 branched from the oil passage 95 is connected to the orifice control valve 105, and the oil passage 115 is selectively connected to a drain port.

In the 2-3 shift valve 71, a port 116 for outputting the 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.

In FIG. 4, reference numeral 121 denotes the second
Indicates an accumulator for the brake B _2, accumulator control pressure linear solenoid valve SLN is pressure regulated in accordance with the hydraulic pressure output is supplied to the back pressure chamber. The accumulator control pressure is configured to increase as the output pressure of the linear solenoid valve SLN decreases. Therefore, the transient hydraulic pressure P _B2 for engaging / disengaging the second brake B ₂ changes at a higher pressure as the signal pressure of the linear solenoid valve SLN is lower. Other clutches C ₁ , C ₂ for shifting
Accumulator is provided in such and brake B _0, by the accumulator control pressure is allowed to act, so that the transient hydraulic pressure in the gear shifting is controlled in accordance with the torque of the input shaft 26.

Further, reference numeral 122 denotes a C-0 exhaust valve, and further reference numeral 123 denotes an accumulator for the clutch C _0. C-0 exhaust valve 1
22 is to operate to engage the clutch C ₀ in order to engine brake only at the second gear of the second speed range.

Therefore, according to the hydraulic circuit 44 described above, if the port 111 of the B-3 control valve 78 is in communication with the drain, the engagement pressure P of the third brake B _3
B3 can be directly regulated by the B-3 control valve 78, and the pressure regulation level can be changed by the linear solenoid valve SLU.

The orifice control valve 10
5 of the spool 106, if the position shown in the left half of the figure, the second brake B ₂ allows ejection pressure through the orifice control valve 105, thus second
It is possible to control the drain rate from the brake B _2.

Further, when shifting from the second gear to the third gear, the third brake B ₃ is gradually released and the second gear is released.
But not so-called clutch-to-clutch shifting gently engage the brake B ₂ is carried out, the third disengagement transition of the brake B ₃ which is driven by the linear solenoid valve SLU based on the input torque T _I to the input shaft 26 By controlling the hydraulic pressure P _B3 , the shift shock can be suitably reduced. The control of the hydraulic pressure P _B3 based on the input torque T _I is as follows:
Can be conducted in real time, such as feedback control, it may perform with respect to the only input torque T _I at the shift start.

As shown in FIG. 2, the hybrid drive device 10 includes a controller 50 for hybrid control and a controller 52 for automatic transmission control. Each of these controllers 50 and 52 is provided with a microcomputer having a CPU, a RAM, a ROM, and the like.
(Corresponding to the output shaft speed N _O of the automatic transmission 18), an accelerator operation amount θ _AC , a throttle valve opening θ _th , a signal indicating a lean state in a cylinder for lean burn control, and the like. The input shaft speed N _I , the engine torque T _E ,
Various kinds of information such as the motor torque T _M , the engine speed N _E , the motor speed N _M , the state of charge SOC of the power storage device 58, the operation range of the shift lever, and ON / OFF of the brake are read, and a preset program is read. The signal processing is performed according to.

[0046] The engine torque T _E is determined from a throttle valve opening theta _th and the fuel injection amount, the charging motor torque T _M is determined from a motor current, the electricity storage amount SOC is the motor-generator 14 functions as a generator It is obtained from the motor current and charging efficiency at the time.

The output of the engine 12 is controlled according to the operating state such as the accelerator operation amount θ _AC by controlling the throttle valve opening θ _th , the fuel injection amount, the ignition timing and the like by the hybrid control controller 50. Is done.

For example, in a predetermined lean burn region (lean burn condition) in which operating conditions such as the throttle valve opening θ _th and the vehicle speed V are defined as parameters.
The lean burn operation for operating the engine 12 at an air-fuel ratio larger than the stoichiometric air-fuel ratio is performed, while the normal operation for operating the engine 12 at the stoichiometric air-fuel ratio is performed in other regions. The lean burn operation is performed based on a signal supplied from the lean sensor 68. A series of signal processing by the hybrid control controller 50 that operates the engine 12 in the normal operation and the lean burn operation corresponds to the engine control means. ing.

The motor generator 14 is connected to a power storage device 58 such as a battery via an M / G controller (inverter) 56 as shown in FIG. And a charge state in which electric energy is supplied to the power storage device 58 by functioning as a generator by regenerative braking (electric braking torque of the motor generator 14 itself). The state is switched to 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 connected to the hybrid control controller 50.
As a result, the hydraulic circuit 44 is switched via an electromagnetic valve or the like, whereby the engaged or released state is switched.

The automatic transmission 18 is controlled by the automatic transmission control controller 52 by the solenoid valves SL1 to SL1.
SL4, linear solenoid valve SLU, SLT, SL
When the excitation state of N is controlled, and the hydraulic circuit 44 is switched or the hydraulic control is performed, the shift speed is switched according to predetermined shift conditions. The shifting conditions are
For example, it is set by a shift map or the like using the running state such as the accelerator operation amount θ _AC and the vehicle speed V as parameters.

The hybrid control controller 50
For example, Japanese Patent Application No. 7-294 filed earlier by the applicant of the present application
As described in No. 148, 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 made, 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. Then, it is determined whether or not a command to start the engine 12 has been issued.

If there is a start request, mode 9 is selected in step S2. Mode 9, the engine 12 via the planetary gear unit 16 by the first clutch CE ₁ As apparent from FIG. 7 engaged (ON), the second clutch CE ₂ engaged (ON), the motor generator 14 , And performs engine start control such as fuel injection to start the engine 12.

[0055] 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, first Clutch CE
₁ is engaged, the motor generator 14 is operated with an output higher than the required output required for traveling, and the engine 12 is rotationally driven with a margin output higher 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.

On the other hand, if the determination in step S1 is denied, that is, if there is no engine start request, step S3 is executed to determine whether there is a request for braking force, for example, whether the brake is ON. Or, the operation range of the shift lever is an engine brake range such as L or 2 (a range in which shift control is performed only at a low speed and the engine brake or regenerative braking is applied) and the accelerator operation amount θ
_The determination is made based on whether _AC is 0, or simply whether the accelerator operation amount θ _AC is 0, or the like.

If this determination is affirmative, step S
Execute Step 4. In step S4, it is determined whether or not the state of charge SOC of power storage device 58 is equal to or greater than a predetermined maximum state of charge B. If SOC ≧ B, mode 8 is selected in step S5, and if SOC <B, step 8 is selected. Mode 6 is selected in S6. The maximum power storage amount B is the maximum power storage amount allowed to charge the power storage device 58 with electric energy, and is set to a value of, for example, about 80% based on the charging / discharging efficiency of the power storage device 58 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, that is, the engine brake is applied to the vehicle, and the brake operation by the driver is reduced. Driving operation becomes easy. 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.

[0059] 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 released and the engine 12 is shut off, there is no energy loss due to the rubbing of the engine 12 and the operation is performed when the state of charge SOC is smaller than the maximum state of charge B. Therefore, the amount of charge SOC of the power storage device 58 does not become excessive and the performance such as charge / discharge efficiency is not impaired.

On the other hand, if the judgment in step S3 is negative, that is, if there is no request for the braking force, step S7 is executed.
Is performed, and it is determined whether or not the start of the engine is requested, for example, based on whether the vehicle is stopped during traveling using the engine 12 as a power source such as mode 3, that is, whether or not the vehicle speed V = 0.

If this judgment is affirmed, step S8 is executed. In step S8, it is determined 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. If the accelerator is ON, mode 5 is selected in step S9, and the accelerator is ON. If not, 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.

More specifically, assuming that the gear ratio of the planetary gear set 16 is ρ _E , engine torque T _E : output torque of the planetary gear set 16: motor torque T _M = 1: (1+
ρ _E ): ρ _E. For example, if the gear ratio ρ _E is set to about 0.5 which is a general value, the motor generator 14 shares half of the engine torque T _E , so that the engine torque T A torque about 1.5 times _E is output from the carrier 16c.

That is, it is possible to start a high torque of (1 + ρ _E ) / ρ _E times the torque of the motor generator 14. Further, if the motor current is cut off to place the motor generator 14 in a no-load state, the rotor shaft 14r
Is only rotated in the reverse direction, the output from the carrier 16c becomes 0, 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, in (1 + ρ _E) times the output torque of the engine torque T _E it is possible to smoothly start the vehicle.

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 motor torque T_MIncrease
Throttle valve opening θ _thAnd increase the fuel injection volume
To increase the output of the engine 12
And the engine speed N due to the increase in the reaction force_ETo fall
This prevents engine stalls and the like.

Mode 7 selected in step S10 includes:
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 rotation of the input shaft 2 of the automatic transmission 18
The output for 6 becomes zero. Accordingly, it is not necessary to stop the engine 12 one by one when the vehicle is stopped while running using the engine 12 as a power source, such as in mode 3, and the engine can be started in mode 5 substantially.

On the other hand, if the determination in step S7 is negative, that is, if there is no request for starting the engine, step S11 is executed, and the required output Pd is set to the first preset value.
It is determined whether the value is equal to or less than the determination value P1. The required output Pd is an output necessary for traveling of the vehicle including the traveling resistance. The required output Pd is based on the accelerator operation amount θ _AC , its changing speed, the vehicle speed V, the gear position of the automatic transmission 18, and the like. It is calculated by an arithmetic expression or the like.

The first judgment 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 energy efficiency, the exhaust gas amount, the fuel consumption amount, and the like are determined by experiments and the like so as to be as small 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. Select On the other hand, SOC <A
If so, the mode 3 is selected in step S14.

The minimum power storage amount A is the minimum power storage amount allowed to take out electric energy from power storage device 58 when the vehicle runs with motor generator 14 as a power source, and is based on the charge / discharge efficiency of power storage device 58 and the like. For example, 7
A value of about 0% is set.

[0074] 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.

Also in this case, since the first clutch CE ₁ is released and the engine 12 is shut off, the friction loss is small as in the case of the mode 6, and the efficiency of the automatic transmission 18 is controlled by appropriately controlling the shift. Good motor drive control is possible.

This mode 1 is executed when the required output Pd is in the low load region where the required output Pd is equal to or less than the first determination value P1 and the state of charge SOC of the power storage device 58 is equal to or greater than the minimum state of charge A. Energy efficiency is superior to that when traveling as a power source, fuel consumption and exhaust gas can be reduced, and the state of charge SOC of the power storage device 58 has a 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.

On the other hand, if the determination in step S11 is negative, that is, if the required output Pd is larger than the first determination value P1, the required output Pd is determined in step S15.
It is determined whether d is greater than the first determination value P1 and less than the second determination value P2, that is, whether P1 <Pd <P2.

The second determination value P2 is a boundary value between a medium load region where the vehicle runs only using the engine 12 as a power source and a high load region where the vehicle runs using both the engine 12 and the motor generator 14 as a power source. In consideration of energy efficiency including time, 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.

If P1 <Pd <P2, it is determined in step S16 whether SOC ≧ A. If SOC ≧ A, mode 2 is selected in step S17, and SOC <A
In the case of, mode 3 is selected in step S14.

If Pd ≧ P2, step S18
It is determined whether or not 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 the mode 4, the first clutch CE ₁ and the second clutch CE ₂ are both engaged (ON), the engine 12 is operated, and the motor generator 14 is driven to rotate. The vehicle is caused to travel at a high output using both of the generators 14 as power sources.

Mode 4 is executed in a high load region where the required output Pd is equal to or greater than the second determination value P2.
And the motor generator 14 are used together, so that the energy efficiency is not significantly impaired as compared with the case where the vehicle runs using only one of the engine 12 and the motor generator 14 as a power source, and the 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 required output P
The power storage device 58 is charged by executing the mode 3 of step S14 in the middle and low load region where d is smaller than the second determination value P2. However, in the high load region where the required output Pd is equal to or more than the second determination value P2, in step S17. Mode 2 is selected, and high-power traveling is performed by the engine 12 without charging.

The mode 2 of step S17 is such that 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 the high load region, the vehicle travels in mode 4 in which the motor generator 14 and the engine 12 are used together.
However, when the state of charge SOC of the power storage device 58 is smaller than the minimum state of charge A, the operation in the mode 2 using only the engine 12 as a power source is performed, so that the state of charge SOC of the power storage device 58 is minimized. It is avoided that the charge amount becomes smaller than the storage amount A and the performance such as charge / discharge efficiency is impaired.

FIG. 8 is a flowchart showing a characteristic operation of the present embodiment to which the first invention is applied, that is, a control operation for improving the fuel efficiency by increasing the frequency of use of the lean burn operation when the vehicle is running. It will be described based on the following. This control
The clutches CE ₁ and CE ₂ are engaged together, the vehicle always travels using the engine 12 as a power source, and torque assist is performed by the motor generator 14 according to predetermined assist conditions. 6 is performed separately. In FIG. 8, steps SA3 and SA5 correspond to the assist control means, and are executed by the hybrid control controller 50.

In FIG. 8, in step SA1, various input signals are sequentially processed by the hybrid control controller 50. Next, in step SA2, it is determined whether or not the vehicle is running lean burn. This decision
For example, the determination is made by determining whether or not the current traveling state is the lean burn operation using a map or the like that is set in advance using the vehicle speed V and the throttle valve opening _θth as parameters. The determination can also be made based on the operating state of the engine 12, for example, a signal from the lean sensor 68 or the like.

If the determination in step SA2 is negative, in step SA3, as shown by the solid line in FIG. 10, torque assist for normal running is performed by the motor generator 14. This torque assist is
Because inevitably peaked input torque T _I to the automatic transmission 18 is in the middle so only the engine 12 as shown by the solid line in FIG. 9 when travels as a power source, the input torque T _I as indicated by the dashed line This is performed in order to change continuously over the entire area. Incidentally, FIG. 9, 10, bold line is the engine speed N _E 2000
Represents when (rpm), the thin line the engine speed N _E 1
It represents the time of 200 (rpm).

On the other hand, if the determination in step SA2 is affirmative, in step SA4, it is determined whether or not the state of charge SOC of power storage device 58 is equal to or greater than a predetermined value α. The predetermined value α is a value that enables the motor generator 14 to perform torque assist.
It is set to the same value as If this determination is affirmed, in step SA5, as shown by the broken line in FIG. 10, the motor generator 14 performs the torque assist for lean burn traveling. This torque assist is used to compensate for the lack of torque during lean burn.
A larger torque assist is performed than during normal running.

[0093] On the other hand, if the determination in step SA4 is negative, since not perform the torque assist by the motor generator 14, in step SA6, so that the throttle valve opening theta _th respect to the accelerator operation amount theta _AC is shown in Figure 11 Is increased by Δθ _th . It should be noted that step SA6 ′ in FIG. 12 is executed instead of this step, and the shift line is shown in FIG. 1 in the shift map set in advance using the accelerator operation amount θ _AC and the vehicle speed V as parameters.
By changing the solid line of FIG. 3 from the solid line to the broken line, it is possible to make up for the lack of torque during lean burn running by using the lower gear (fourth gear) more frequently than the higher gear (fifth gear). Similarly, the upshift line and other shift lines are changed to the high vehicle speed side and the low accelerator operation amount side.

As described above, according to the present embodiment, during the lean burn operation, the motor generator 14 provides a larger torque assist for the lean burn operation than during the normal operation in step SA5. Insufficiency is less likely to occur, and it is possible to reduce the frequency of running the engine 12 near the stoichiometric air-fuel ratio to avoid torque shortage due to lean burn operation, thereby further improving fuel efficiency.

FIG. 14 is a flowchart showing a characteristic part of the present embodiment to which the second invention is applied, that is, a control operation for improving the fuel efficiency by increasing the frequency of use of the lean burn operation when the vehicle is running. It will be described based on the following. In FIG. 14, step SB5 corresponds to the assist control means and is executed by the hybrid control controller 50.

In FIG. 14, in step SB1, various input signals are sequentially processed by the hybrid control controller 50. Next, in step SB2, it is determined whether the vehicle is running lean burn. This determination is made by determining whether or not the current running state is the lean burn operation, based on a map or the like set in advance using the vehicle speed V and the throttle valve opening _θth as parameters, as in step SA2. .

If the determination in step SB2 is affirmative, it is determined in step SB3 whether the rate of change Δθ _AC of the accelerator operation amount is equal to or greater than a predetermined value β. The predetermined value β is set to such a value that switching from lean burn running to normal running is performed without torque assist by the motor generator 14. This predetermined value β is
It is desirable that the speed be appropriately changed according to the vehicle speed V, the engine water temperature, the engine intake air amount, and the like.

If the determination in step SB3 is affirmative, it is determined in step SB4 whether or not the state of charge SOC of power storage device 58 is equal to or greater than a predetermined value α. If this determination is affirmed, torque assist is performed by motor generator 14 in step SB5. This torque assist is performed so that the current running state does not protrude from the lean burn region, in other words, the lean burn condition is satisfied, in a map or the like which is set in advance using the vehicle speed V and the throttle valve opening _θth as parameters. This is performed so as to compensate for the lack of torque. Specifically, when an acceleration request of Δθ _AC ≧ β is requested, the throttle valve opening θ _th is increased accordingly. However, the throttle valve opening θ _th is maintained in the lean burn region, and the insufficient motor torque is supplemented by the motor generator 14. It is.

On the other hand, if the determination in step SB4 is negative, torque assist by the motor generator 14 cannot be performed, and in step SB6, the engine 12 is turned near the stoichiometric air-fuel ratio from lean burn running so that torque shortage does not occur. Is switched to the normal running.

As described above, according to the present embodiment, during the lean burn operation, in step SB5, the torque assist is performed by the motor generator 14 so that the current running state does not protrude from the predetermined lean burn region. As a result, the current running state easily satisfies the lean burn condition.
The frequency of traveling by operating the vehicle can be suppressed low, so that the fuel efficiency can be further improved.

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the above-described embodiment,
Although the automatic transmission 18 having five speeds and five forward speeds has been used, as shown in FIG. 15, the automatic transmission 60 comprising only the main transmission 22 without the sub-transmission 20 is used. It is also possible to adopt the above, and to perform the shift control at four forward speeds and one reverse speed as shown in FIG.

The present invention can be applied in various other modes without departing from the gist of the present invention.

[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 provided 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 of 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 flowchart illustrating a main part of a control operation to which the first invention is applied.

FIG. 9 is a diagram exemplifying an input torque T _I of the automatic transmission obtained with respect to an accelerator operation amount θ _AC , in which a solid line indicates a case where only the engine is used as a power source, and a broken line indicates torque assist by a motor generator. Is performed.

FIG. 10 is a diagram exemplifying a torque assist amount by the motor generator 14 with respect to an accelerator operation amount θ _AC , in which a solid line indicates a value during normal running, and a broken line indicates a value during lean burn driving.

FIG. 11 is a diagram exemplifying an increase Δθ _th for changing a transient characteristic of a throttle valve opening θ _{th with} respect to an accelerator operation amount θ _AC .

FIG. 12 is a diagram showing a step SA6 ′ that can be executed instead of step SA6 in FIG. 8;

FIG. 13 is a diagram exemplifying a shift map that is set in advance by using an accelerator operation amount θ _AC and a vehicle speed V as parameters, wherein a solid line indicates a case of normal running, and a broken line indicates a case of lean burn running. ing.

FIG. 14 is a flowchart illustrating a main part of a control operation to which the second invention is applied.

FIG. 15 is a skeleton view illustrating a configuration of a hybrid drive device including an automatic transmission different from the embodiment of FIG. 1;

16 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: Hybrid control controller 68: Lean sensor (engine control means) Step SA3, SA5: Assist control means Step SB5: Assist control means

Continued on the front page (72) Inventor Yuji Hata 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Tsuyoshi Tsuyoshi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (2)

[Claims] 1. An ordinary operation for operating an engine operating at a stoichiometric air-fuel ratio while providing an engine that operates by burning fuel and an electric motor that operates by electric energy as a power source when the vehicle runs. A control device for a hybrid vehicle having engine control means capable of performing lean-burn operation for operating the engine at an air-fuel ratio larger than the air-fuel ratio, wherein a larger torque assist is provided by the electric motor during the lean-burn operation than during the normal operation. A control device for a hybrid vehicle, comprising: an assist control unit for performing the control. 2. An engine that operates by burning fuel and an electric motor that operates by electric energy are provided as power sources for driving the vehicle, and when a predetermined lean burn condition is satisfied, a theoretical idle In a control device for a hybrid vehicle having an engine control means for performing a lean burn operation for operating the engine with an air-fuel ratio larger than a fuel ratio, an assist control means for performing torque assist by the electric motor so as to satisfy the lean burn condition is provided. A control device for a hybrid vehicle, comprising: