JPH11332011A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To select the motor of a hybrid vehicle, wherein its smooth start and acceleration performances is ensured by the minimum capacity of the motor. SOLUTION: In a hybrid vehicle, an engine 2 is coupled to the input shaft of a clutch 3, and the input shaft of a motor 4 connected in series with a transmission 5 is coupled to the output shaft of the clutch 3, and furthermore, the power of the hybrid vehicle is transmitted from the output shaft of the transmission 5 to drive wheels 8. With respect to the hybrid vehicle, the characteristic of having a constant torque region and a constant-power region is given to the motor 4, and the rated torque of the motor 4 which is specified in the lower speed of the hybrid vehicle than a specified vehicle speed is selected to be larger than the rated torque of the engine 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an engine and / or an engine.
Alternatively, the present invention relates to a hybrid vehicle using a motor as a propulsion source of the vehicle.

[0002]

2. Description of the Related Art A hybrid vehicle using an engine and / or a motor as a propulsion source of the vehicle is known (for example, see Japanese Patent Application Laid-Open No. 5-50865). In this type of hybrid vehicle, at the time of a normal start, the clutch is released and the vehicle is started by the driving force of the motor. When the vehicle speed increases, the engine is started, the clutch is engaged, and the vehicle is driven by the driving force of the engine.

[0003]

By the way, when the engine immediately after starting has a large torque fluctuation and sudden acceleration is performed,
When the clutch is engaged immediately after the start of the engine, fluctuations in the torque of the engine are transmitted to the driving wheels, and vibrations in the front-rear direction are generated in the vehicle, which causes occupants to feel uncomfortable.

[0004] In order to solve this problem, the motor is increased in capacity and almost started only by the driving force of the motor.
If the acceleration is performed, the clutch engagement time can be delayed, and the clutch can be engaged after the generated torque of the engine is stabilized.

[0005] However, when the capacity of the motor is increased, not only the motor itself, but also the power converter and the battery become large and heavy, and the cost increases.

An object of the present invention is to select a motor having a minimum capacity that can guarantee a smooth start and acceleration performance.

[0007]

The present invention will be described with reference to FIG. 1 showing the configuration of one embodiment. (1) The invention of claim 1 connects the engine 2 to the input shaft of the clutch 3. At the same time, the motor 4 and the input shaft of the transmission 5 are connected to the output shaft of the clutch 3, and the motor 4 is connected to the constant torque region for a hybrid vehicle that transmits power from the output shaft of the transmission 5 to the drive wheels 8. The above-described object is achieved by providing a characteristic having a constant output region and selecting the rated torque of the motor 4 to be larger than the rated torque of the engine 2 below a predetermined vehicle speed. (2) According to a second aspect of the present invention, the predetermined vehicle speed is equal to or higher than the vehicle speed determined by the base rotational speed of the motor 4 and the maximum speed ratio of the transmission 5. (3) In the invention of claim 3, the vehicle runs by the driving force of the engine 2 in the rotation speed region of the motor 4 in which the rated torque of the engine 2 is larger than the rated torque of the motor 4. (4) The invention according to claim 4 is such that the rotation speed of the motor 4 at which the rated torque of the engine 2 is equal to the rated torque of the motor 4 is equal to or close to the base rotation speed of the motor 4. Select the rating of the motor 4.

In the section of the means for solving the above-mentioned problems, a diagram of an embodiment is used for easy understanding of the description, but the present invention is not limited to the embodiment. .

[0009]

(1) According to the first aspect of the present invention, even if there is a large torque fluctuation during the transition immediately after the start of the engine, the torque fluctuation of the engine can be absorbed by adjusting the motor torque, and before and after the clutch is engaged. Thus, the sum of the engine torque and the motor torque, that is, the driving torque of the vehicle can be made constant. Particularly, when the vehicle is suddenly started, the engine is started and accelerated by the driving force of the engine and the motor while the clutch is half-engaged, so that a large torque fluctuation of the engine immediately after the start is easily transmitted to the drive wheels. According to the present invention, even at such a sudden start, the torque fluctuation of the engine can be absorbed by adjusting the torque of the motor, and a constant driving torque can be obtained before and after the clutch is engaged.
In addition, even when starting, accelerating, or performing low-load, high-load driving using the driving force of the motor, it is possible to obtain greater acceleration and driving power than with conventional engine vehicles, and it is necessary to use an engine with low speed and poor driving efficiency. Therefore, the fuel consumption rate can be improved. (2) According to the second aspect of the invention, it is possible to select a motor having the minimum capacity while guaranteeing smooth start and acceleration performance, and reduce the cost and weight of the hybrid vehicle. (3) According to the third and fourth aspects of the present invention, a high-speed, high-output motor is not required by driving with an engine having high driving efficiency in a high vehicle speed range, and the motor capacity can be reduced.

[0010]

FIG. 1 is a diagram showing the configuration of an embodiment. In the figure, a thick solid line indicates a transmission path of mechanical force, and a thick broken line indicates a power line. A thin solid line indicates a control line, and a double line indicates a hydraulic system. The power train of this vehicle includes a motor 1, an engine 2, a clutch 3, a motor 4, a continuously variable transmission 5, a reduction gear 6, a differential gear 7, and driving wheels 8. The output shaft of the motor 1, the output shaft of the engine 2, and the input shaft of the clutch 3 are connected to each other, and the output shaft of the clutch 3, the output shaft of the motor 4, and the input shaft of the continuously variable transmission 5 are connected to each other. ing.

When the clutch 3 is engaged, the engine 2 and the motor 4 serve as propulsion sources for the vehicle. When the clutch 3 is released, only the motor 4 serves as a propulsion source for the vehicle. The driving force of the engine 2 and / or the motor 4 is transmitted to the drive wheels 8 via the continuously variable transmission 5, the reduction gear 6, and the differential 7. Pressure oil is supplied from the hydraulic device 9 to the continuously variable transmission 5 to clamp and lubricate the belt. An oil pump (not shown) of the hydraulic device 9 is driven by a motor 10.

The motors 1, 4, and 10 are AC machines such as a three-phase synchronous motor or a three-phase induction motor. The motor 1 is mainly used for engine start and power generation, and the motor 4 is mainly used for vehicle propulsion and braking. . The motor 10 is for driving the oil pump of the hydraulic device 9. In addition,
The motors 1, 4, and 10 are not limited to AC machines, and DC motors can be used. Further, when the clutch 3 is engaged, the motor 1 can be used for propulsion and braking of the vehicle, and the motor 4 can be used for starting the engine and generating power.

The clutch 3 is a powder clutch, and can adjust a transmission torque. It should be noted that a dry single-plate clutch or a wet multi-plate clutch can be used as the clutch 3. The continuously variable transmission 5 is a continuously variable transmission of a belt type, a toroidal type, or the like, and can continuously adjust the speed ratio. This transmission may be a transmission with a break.

The motors 1, 4, and 10 are driven by inverters 11, 12, and 13, respectively. When a DC motor is used for the motors 1, 4, and 10, a DC / DC converter is used instead of the inverter.
The inverters 11 to 13 are connected to a main battery 15 via a common DC link 14, convert DC charging power of the main battery 15 into AC power, supply the AC power to the motors 1, 4, 10, and 4 is converted into DC power and the main battery 1
Charge 5. Since the inverters 11 to 13 are connected to each other via the DC link 14, the power generated by the motor during the regenerative operation can be directly supplied to the motor during the power running operation without passing through the main battery 15. it can. The main battery 15 contains lithium
Various batteries such as an ion battery, a nickel-metal hydride battery, a lead battery, and an electric double layer capacitor, a so-called power capacitor, can be used.

The controller 16 includes a microcomputer and its peripheral parts, various actuators, etc., and controls the rotation speed and output torque of the engine 2, the transmission torque of the clutch 3, the rotation speed and output torque of the motors 1, 4, and 10. The gear ratio of the transmission 5 is controlled.

As shown in FIG. 2, the controller 16 includes a key switch 20, a select lever switch 21,
An accelerator sensor 22, a brake switch 23, a vehicle speed sensor 24, a battery temperature sensor 25, a battery SOC detection device 26, an engine rotation sensor 27, and a throttle opening sensor 28 are connected. Key switch 2
0 is closed when the vehicle key is set to the ON position or the START position.
Open circuit is called OFF or OFF). The selector lever switch 21 is provided for parking P, neutral N, and reverse R.
One of the switches P, N, R, and D is turned on according to the setting position of a select lever (not shown) for switching the drive D.

The accelerator sensor 22 detects the amount of depression of the accelerator pedal (accelerator opening) θ, and the brake switch 23 detects the state of depression of the brake pedal (switch on at this time). The vehicle speed sensor 24 detects the running speed V of the vehicle, and the battery temperature sensor 25 detects the temperature Tb of the main battery 15. The battery SOC detection device 26 detects the state of charge of the main battery 15 (hereinafter, referred to as SOC (State Of Charge)). Further, the engine rotation sensor 27 detects the rotation speed Ne of the engine 2 and the throttle opening sensor 28 detects the throttle valve opening θth of the engine 2.

The controller 16 also includes the engine 2
, An ignition device 31, a valve timing adjusting device 32, a throttle valve opening adjusting device 33, an auxiliary battery 34, and the like. Controller 1
6 controls the fuel injection device 30 to supply and stop fuel to the engine 2 and adjust the fuel injection amount, and controls the ignition device 31 to ignite the engine 2. Also,
The controller 16 controls the valve timing adjusting device 32 to adjust the closing timing of the intake valve of the engine 2 and controls the throttle valve opening adjusting device 33 to adjust the throttle valve opening θth of the engine 2. This throttle valve opening adjusting device 33 is not mechanically connected to the accelerator pedal, and adjusts the opening θth independently of the depression amount θ of the accelerator pedal. The auxiliary battery 34 supplies low-voltage power to the controller 16.

FIGS. 3 and 4 are diagrams showing examples of the arrangement of the power train. Regarding the arrangement of the motor 1 and the engine 2 on the input side of the clutch 3, the motor 1 may be arranged upstream of the engine 2 as shown in FIG. 3, or the motor 1 may be arranged downstream of the engine 2 as shown in FIG. It may be arranged. In the arrangement example shown in FIG. 3, the output shaft of the engine 2 is directly connected to the input shaft of the clutch 3 to form a single shaft, and the output shaft of the engine 2 is connected to the output shaft of the motor 1 by a belt or a gear. In the arrangement example shown in FIG. 4, the output shaft of the engine 2 is directly connected to the input shaft of the clutch 3 through the rotor of the motor 1, and the input side of the clutch 3 is constituted by one shaft.

On the other hand, the motor 4 on the output side of the clutch 3 and the continuously variable transmission 5 may be arranged such that the motor 4 is arranged upstream of the continuously variable transmission 5 as shown in FIG. As shown, the motor 4 may be arranged downstream of the continuously variable transmission 5. In the arrangement example shown in FIG. 3, the output shaft of the clutch 3 is directly connected to the input shaft of the continuously variable transmission 5 through the rotor of the motor 4, and the output side of the clutch 3 is constituted by one shaft. In the arrangement example shown in FIG. 4, the output shaft of the clutch 3 is directly connected to the output shaft of the motor 4 through the input shaft of the continuously variable transmission 5, and the output side of the clutch 3 is constituted by one shaft. In any case, the motor 4 is connected to the input shaft of the continuously variable transmission 5.

The arrangement of the power train is not limited to the arrangement examples shown in FIGS. 3 and 4. The engine 2 and the motor 1 are connected to the input shaft of the clutch 3, and the motor 4 is not connected to the output shaft of the clutch 3. What is the type of propulsion mechanism that connects the input shaft of the stepless transmission 5 and transmits power from the output shaft of the continuously variable transmission 5 to the drive wheels 8 via the reduction gear 6 and the differential device 7? It may be arranged.

FIG. 5 shows an example of an arrangement of a power train using a toroidal CVT for a continuously variable transmission. Either the motor 4 or the toroidal CVT 5 may be arranged on the clutch 3 side even when a toroidal CVT is used for the continuously variable transmission 5. However, in any case, the motor 4 is connected to the input shaft of the continuously variable transmission 5.

In this embodiment, the vehicle basically travels with the driving force of the motor 4 at low speed and light load, and travels with the driving force of the engine 2 at high speed and high load. Therefore,
When the vehicle is started from a stopped state, the vehicle is started and accelerated by the driving force of the motor 4, the clutch 3 is engaged halfway, and the driving is switched to the driving by the engine 2.

When the temperature of the engine cooling water is equal to or higher than a predetermined value, the engine 2 is in a warm-up state, and the main battery 15
If the SOC is equal to or higher than a predetermined value and the charge amount is sufficient, "idling stop" is performed when the vehicle stops at a traffic light or the like.
Improve fuel consumption rate. However, when the engine cooling water temperature is lower than the predetermined value and the engine 2 is in a cold state, or when the SOC of the main battery 15 is lower than the predetermined value and the charge amount is insufficient, the idling stop is not performed and the vehicle is stopped. However, the ignition operation of the engine 2 is continued.

Therefore, when starting from a stopped state, the ignition operation of the engine 2 is started and the clutch 3 is engaged to switch the mode from motor running to engine running. And the mode is switched from motor running to engine running. In this specification, the former is called "idle stop mode" and the latter is called "normal mode". The idle stop mode includes acceleration from low-speed running by the driving force of the motor 4 in addition to starting from a stopped state.

FIG. 6A shows the rotational speed Ne of the engine 2 and the rotational speed Nm of the motor 4 at the time of starting and accelerating in the idle stop mode. FIG. 6B shows the torque Te of the engine 2 and the torque Tm of the motor 4 when starting and accelerating in the idle stop mode. Starting and accelerating operations in the idle stop mode will be described with reference to these drawings. In the acceleration from the start and the low-speed running in the idle stop mode, first, the motor 4 generates a torque Tm corresponding to the vehicle speed V and the accelerator pedal depression amount (accelerator opening degree) θ to accelerate the vehicle. As the vehicle speed V increases, the rotation speed Nm of the motor 4 also increases. Next, the engine 2 is driven by the motor 1, and the ignition operation of the engine 2 is started. The reason why the engine torque Te becomes negative immediately after the start of the engine is that the engine 2 is driven and rotated by the motor 1 and generates a positive engine torque Te when the engine 2 completely explodes.

If there is a speed difference between the input and output shafts of the clutch 3 when the clutch is engaged, an impact occurs. Therefore, it is necessary to make the rotational speed Nm of the motor 4 and the rotational speed Ne of the engine 2 coincide when the clutch is engaged. Therefore, after the engine is started, the timing at which the rotation speed Ne of the engine 2 reaches the rotation speed Nm of the motor 4 is calculated, and the engagement timing of the clutch 3 is determined.

On the other hand, when the clutch 3 is engaged, the torque Te of the engine 2 is added to the torque Tm of the motor 4. If the motor torque Tm is constant before and after the clutch is engaged, the drive torque increases by the engine torque Te after the clutch is engaged. As a result, the vehicle is accelerated in spite of the fact that the accelerator pedal depression amount θ is constant, giving the occupant a sense of discomfort. Therefore, it is necessary to prevent the drive torque from changing before and after the clutch is engaged.

Therefore, in this embodiment, the torque generated by the engine 2 when the clutch is engaged is predicted, and the sum of the motor torque Tm after the clutch engagement and the engine torque Te is equal to the motor torque Tm before the clutch engagement. Thus, the motor torque Tm after the clutch is engaged is calculated, and is set as the target torque of the motor 4 after the clutch is engaged.

FIG. 7 is a diagram showing a change in generated torque immediately after the engine is started. In general, the torque Te of the engine rapidly increases immediately after startup, and overshoots before reaching a stable level depending on the throttle valve opening θth and the engine speed Ne.

In this embodiment, at the calculated clutch engagement time, the difference between the motor rotation speed Nm and the engine rotation speed Ne is within a predetermined difference, and the calculated target motor torque Tm is equal to the rated torque of the motor 4. If it is within Tm, the engagement of the clutch 3 is determined. As a result, it is possible to prevent the occurrence of an impact at the time of clutch engagement, and to obtain a constant acceleration force before and after the clutch engagement without changing the drive torque before and after the clutch engagement.

The speed ratio i of the continuously variable transmission 5 is the maximum speed ratio imax until the engine speed Ne (= motor speed Nm) reaches a predetermined value after the clutch is engaged.
Therefore, the motor torque Tm is greatly amplified at the time of starting or accelerating from low-speed running, and high starting and acceleration performance can be realized with a small-capacity motor.

When the engine rotation speed Ne (= Nm) exceeds a predetermined value, the gear ratio control is started in accordance with the gear ratio control pattern as shown in FIG.
The gear ratio control pattern is set in advance based on the vehicle speed V and the engine rotation speed Ne (= motor rotation speed Nm). As a result, the maximum rotation speed Nt of the motor 4 can be kept low, and it is not necessary to use a high-speed motor for the motor 4, so that the cost can be reduced.

Next, the relationship between the rated torque ΔTe of the engine 2 and the rated torque ΔTm of the motor 4 according to this embodiment will be described. FIG. 8 is a diagram illustrating torque characteristics of the engine 2 and the motor 4. For the engine 2 having a constant torque characteristic in which the rated torque ΔTe with respect to the rotation speed Ne is almost constant,
A constant torque region (rotation speed 0 to base rotation speed Nb) where the rated torque ΔTm is constant with respect to the rotation speed Nm;
The motor 4 having a constant output region (base rotation speed Nb to maximum rotation speed Nt) where the rated output ΔPm with respect to is constant.

Further, in this embodiment, when the vehicle speed V is less than the predetermined value V1,

## EQU1 ## The ratings of the engine 2 and the motor 4 are selected so that ＠Tm> ＠Te. The predetermined vehicle speed V1 is a vehicle speed determined by the base rotation speed Nb of the motor 4 and the maximum speed ratio imax, or a value near the vehicle speed.

V1 = Nb / (k * imax) In Equation 2, k is a constant determined by a power transmission mechanism other than the continuously variable transmission 5.

Since the predetermined vehicle speed V1 changes according to the maximum speed ratio imax, the ratings of the engine 2 and the motor 4 may be specified using the motor rotation speed Nm. That is, when the motor rotation speed Nm is lower than the base rotation speed Nb, the ratings of the engine 2 and the motor 4 are selected so as to satisfy the relationship of Expression 1.

In this embodiment, when the vehicle speed V <V1 (or Nm <Nb), the engine 2 and the motor 4 are selected so that ＠Tm> ＠Te. When the vehicle speed V <V1, the vehicle runs by the driving force of the motor 4 unless a large driving torque is required or the remaining amount of the battery is small.

As is apparent from FIG. 8, since a motor having a constant torque region and a constant output region is selected for the motor 4, the rated torque ΔTm is increased in the constant output region in accordance with the increase of the rotation speed Nm. Decrease. The magnitude relationship between the rated torques of the engine 2 and the motor 4 is represented by the rotation speed N1.
(= The input shaft rotation speed of the continuously variable transmission 5), and the engine rated torque ＠Te becomes larger than the motor rated torque ＠Tm. Therefore, in the engine 2 and the motor 4 selected based on the condition of the above equation 1, in a region where the rotation speed N1 or more satisfies ＠Te> ＠Tm, a large driving torque is required under a high load or the like (in this case, the engine + motor )
Except for, the vehicle mainly runs by the driving force of the engine 2.

Next, when the vehicle speed V <V1 (or Nm <Nb), the motor rated torque {Tm> engine rated torque}
The effect when Te is set will be described. Predetermined vehicle speed V1
If it is less than the rated torque ΔTm of the engine 2, the rated torque ΔTm of the motor 4 is larger than the rated torque ΔTe of the engine 2. Fluctuations can be absorbed and the engine torque T before and after the clutch is engaged.
The sum of e and the motor torque Tm, that is, the driving torque of the vehicle can be kept constant. Since the motor can also generate negative torque, active control that almost completely cancels out engine torque fluctuations is also possible (control is relatively easy at low speeds) and smoothly outputs the torque expected by the driver. Can be done. In particular, when the vehicle is suddenly started, the engine is started, the clutch is engaged in a relatively short time from a half-engaged state, and the engine and the motor are started and accelerated by the driving force. Easy to reach the wheel. According to the present invention, even at such a sudden start, the torque fluctuation of the engine can be absorbed by adjusting the torque of the motor, and a constant driving torque can be obtained before and after the clutch is engaged.

In a conventional engine vehicle, the torque converter amplifies the engine torque at the time of starting, and obtains a large driving torque. In the hybrid vehicle of this embodiment, the vehicle must run only with the driving force of the motor 4 until the clutch 3 is engaged, but the motor 4 is connected to the input shaft of the continuously variable transmission 5 and
Since the motor 4 is selected such that ＠Tm> ＠Te at the vehicle speed V <V1 (or Nm <Nb), a driving torque equivalent to that of an engine vehicle with a torque converter having a conventional torque amplifying function can be obtained when starting and accelerating. As a result, sufficient starting and acceleration performance can be obtained.

Further, by setting the maximum speed ratio imax to a value as small as permissible, the motor driving range can be expanded, and the engine 2 can be driven in a high vehicle speed range with high driving efficiency. In addition, the fuel consumption rate can be improved.

Further, at low speed and high load such as climbing a hill, the motor torque Tm is larger than the engine torque Te.
If it is possible to obtain the assist of the engine 2, since it is possible to avoid the area of the high load which is likely to cause knocking of the engine, the high compression of the engine 2 which has conventionally been difficult to avoid knocking at low speed and high load The ratio can be improved, and the fuel consumption rate can be improved.

On the other hand, in this embodiment, a motor having a characteristic having a constant torque region and a constant output region is selected as the motor 4, and the driving force of the engine 2 is selected in the region of the rotation speed N1 or more where ΔTe> ΔTm. , The effect of which will be described. When the vehicle runs to the middle or high speed region by the driving force of the motor 4, the capacity of the motor 4 needs to be increased, and the power converter 12 and the main battery 1
5, including cost, weight, installation space, etc., increase. For example, in order to obtain the same driving torque as the engine 2 at the maximum speed, it is necessary to make the capacity of the motor 4 equal to that of the engine and the battery output to correspond to this. Is lost. In this embodiment, a motor having a characteristic having a constant torque region and a constant output region is selected as the motor 4, and when the vehicle speed V <V1 (or Nm <Nb), ΔTm
> ＠Te, and the rotation speed N1 that satisfies ＠Te> ＠Tm
In the above-described region, the vehicle is driven by the driving force of the engine 2, so that the motor 4, the power converter 12, and the main battery 15 can be reduced in size and weight while maintaining high starting and accelerating performance. Can be reduced.

When the vehicle is decelerated, regenerative braking is applied by the motor 4 to recover energy and improve the fuel consumption rate. When a large-capacity motor is used as the motor 4, a large braking force may be applied when regenerative power generation control becomes impossible. In this embodiment, a motor having a characteristic having a constant torque region and a constant output region is selected as the motor 4, and when the vehicle speed V <V1 (or Nm <Nb), ΔTm
> ＠Te, and in the region of the rotation speed N1 or more, ＠Te
Since the motor rating is selected so as to be> mTm, the regenerative braking force becomes equal to the conventional engine braking force, and the occupant does not feel uneasy even in the event of an emergency.

By setting Nb ≒ N1, the motor 4 is maintained while maintaining the above-mentioned starting and acceleration performance.
Can be reduced in size, weight, and cost.

FIG. 9 is a flowchart showing start and acceleration operations in the idle stop mode. The operation of the embodiment will be described with reference to this flowchart. In step 1, it is determined whether or not the engine is in the idle stop mode based on the cooling water temperature of the engine 2 and the SOC of the main battery 15. In the following step 2, clutch engagement is determined based on the vehicle speed V and the accelerator pedal depression amount (accelerator opening) θ. The clutch engagement determination is shown in FIG.
When the intersection of the vehicle speed V and the accelerator opening .theta. At the time of the determination enters the blank area from the hatched area, the clutch engagement is determined. FIG.
0, when the vehicle speed V is lower than the predetermined value V2 in a low speed state, the rotation speed of the engine 2 is reduced, and the fuel consumption performance and the exhaust purification performance are reduced. Therefore, even if the accelerator depression amount θ corresponding to the required driving force is large, the motor The vehicle runs with only four driving forces. Here, as the predetermined value V2, for example, a vehicle speed when the engine speed is 200 to 300 [rpm] is set.
In this case, if the remaining battery power is low, the engine is rotated at an appropriate speed (eg, 1200 rpm) with the clutch off.
It is also possible to run the motor while charging the battery while generating power.

When the clutch is determined to be engaged, the routine proceeds to step 3, where the engine 1 is driven by the motor 1 and the ignition operation of the engine 2 is started. In the following step 4, the timing at which the engine rotation speed Ne reaches the motor rotation speed Nm is calculated based on the changes in the engine rotation speed Ne and the motor rotation speed Nm after the start of the engine, and the engagement timing of the clutch 3 is determined. Next, in step S5, the generated torque of the engine 2 is predicted. In the following step S6, the clutch engagement is performed such that the sum of the motor torque Tm after the clutch engagement and the engine torque Te becomes equal to the motor torque Tm before the clutch engagement. The subsequent target torque Tm of the motor 4 is calculated.

In step 7, the motor rotation speed N
If the difference between m and the engine rotation speed Ne is within a predetermined difference, and the calculated target motor torque Tm is within the rated torque of the motor 4 ＠Tm, no impact is generated when the clutch is engaged. Since the torque fluctuation of the engine 2 immediately after the start can be absorbed by the torque control of the motor 4, the engagement of the clutch 3 is determined. Then, in step 8, the clutch 3 is engaged.

In step 9 immediately after the engagement of the clutch,
The torque control is performed so that the output torque Tm of the motor 4 becomes the calculated target value. As a result, as shown in FIG. 6B, the sum of the engine torque Te and the motor torque Tm after the clutch is engaged becomes equal to the motor torque Tm before the clutch is engaged, and the drive torque changes before and after the clutch is engaged. Instead, a continuous and constant acceleration becomes possible. Thereafter, as the vehicle speed V increases, the output torque Tm of the motor 4 increases.
, The engine torque Te is increased, and the motor running is gradually switched to the engine running.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment.

FIG. 2 is a diagram illustrating a configuration of an embodiment following FIG. 1;

FIG. 3 is a diagram illustrating an example of an arrangement of a power train according to an embodiment;

FIG. 4 is a diagram illustrating another arrangement example of the power train according to the embodiment;

FIG. 5 is a diagram showing another arrangement example of the power train according to the embodiment;

FIG. 6 shows the engine rotation speed Ne before and after the clutch engagement,
FIG. 4 is a diagram illustrating a motor rotation speed Nm, an engine torque Te, and a motor torque Tm.

FIG. 7 is a diagram showing a change in output torque Te immediately after the engine is started.

FIG. 8 is a diagram showing torque characteristics with respect to rotation speeds of an engine and a motor.

FIG. 9 is a flowchart illustrating a start operation in an idle stop mode according to one embodiment.

FIG. 10 is a diagram showing an example of a clutch engagement determination map.

[Description of Signs] 1, 4, 10 Motor 2 Engine 3 Clutch 5 Continuously variable transmission 6 Reduction gear 7 Differential gear 8 Driving wheel 9 Hydraulic equipment 11-13 Inverter 14 DC link 15 Main battery 16 Controller 20 Key switch 21 Select Lever switch 22 Accelerator sensor 23 Brake switch 24 Vehicle speed sensor 25 Battery temperature sensor 26 Battery SOC detector 27 Engine rotation sensor 28 Throttle opening sensor 30 Fuel injection device 31 Ignition device 32 Valve timing adjustment device 33 Throttle valve opening adjustment device 34 Auxiliary battery

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yuya Matsuo 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd.

Claims (4)

[Claims] 1. A hybrid vehicle in which an engine is connected to an input shaft of a clutch, a motor and an input shaft of a transmission are connected to an output shaft of the clutch, and power is transmitted from the output shaft of the transmission to drive wheels. On the other hand, the motor has a characteristic having a constant torque region and a constant output region, and is selected such that the rated torque of the motor is larger than the rated torque of the engine when the vehicle speed is lower than a predetermined vehicle speed. Hybrid vehicle. 2. The hybrid vehicle according to claim 1, wherein the predetermined vehicle speed is equal to or higher than a vehicle speed determined by a base rotation speed of the motor and a maximum speed ratio of the transmission. 3. The hybrid vehicle according to claim 1, wherein the vehicle is driven by the driving force of the engine in a rotation speed range of the motor in which a rated torque of the engine is larger than a rated torque of the motor. A hybrid vehicle characterized by the above. 4. The hybrid vehicle according to claim 3, wherein the rotation speed of the motor at which the rated torque of the engine is equal to the rated torque of the motor is equal to or close to the base rotation speed of the motor. A hybrid vehicle characterized by selecting a rating of the motor so that