JP2000225858A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a clutch means, maintaining traveling performance, in a parallel type hybrid vehicle with the clutch means interposed between an engine and a drive wheel. SOLUTION: A motor 2 for traveling is directly connected with drive wheels 9, 10. An engine 1 is connected with the drive wheels 9, 10 via a torque converter 5 and an automatic transmission 7. The automatic transmission 7 switches to an N range and a gear shift range at the same time as the transmission 7 performs gear shift and intermits driving force of the engine. A general control ECU 100 judges a traveling state based on a rate of change of accelerator stepping amount. By quickly performing a gear shift of the automatic transmission 7 by judging time when the rate of change is large as acceleration traveling and slowly performing a gear shift of the automatic transmission 7 by judging time when the rate of change is small as stationary traveling, the automatic transmission 7 is protected. By slowly performing a gear shift of the automatic transmission 7 also when a torque converter 5 is in a lock up state, the automatic transmission 7 is protected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle that runs using both an engine and a motor.

[0002]

2. Description of the Related Art Hitherto, a so-called series system has been known as a hybrid vehicle (see, for example, JP-A-6-165309). In this device, a generator is driven by an engine to generate electric power, and the electric power is stored in a battery. Then, electric power is supplied from a battery to the motor, and a driving force for traveling is obtained by the motor.

[0003] On the other hand, what is called a parallel system is known as a hybrid vehicle. In this case, the vehicle is configured to run using both an electric motor and an engine. In other words, the point that the battery is charged by driving the generator by the engine is the same as the above-mentioned series system, but different from the series system, not only the traveling by the motor driven by the electric power of the battery but also the traveling by the engine alone or the engine. It is configured to be able to run by both the motor and the motor. When the vehicle is started, the vehicle is driven by a motor. When the vehicle speed increases and the engine can be driven with efficient rotation, the driving source is switched from the motor to the engine and the vehicle is driven. Further, when a large driving force is required such as sudden start or sudden acceleration, the vehicle is driven by both the motor and the engine.

[0004] In the above-mentioned parallel type hybrid vehicle, there has been proposed a hybrid vehicle in which a motor is directly connected to driving wheels, while an engine is connected to the driving wheels via a clutch. In this type of hybrid vehicle, the clutch is disengaged when the vehicle runs only by the motor, and the clutch is engaged when the vehicle runs only on the engine or both the engine and the motor.

[0005]

As described above, in the hybrid vehicle of the parallel system, the driving force of the engine is transmitted to the driving wheels from the middle while the motor is running. That is, the clutch is engaged during traveling. Therefore,
If the clutch is engaged in a state where the rotation difference between the drive wheel side and the engine side of the clutch is large, there is a problem that the clutch is damaged. Even if the clutch is not damaged, for example, if the clutch is engaged while the engine speed is low, a shock will be generated due to deceleration of the vehicle body, the running state will be unstable, and the driver will feel uncomfortable. There was a problem that would give.

On the other hand, when the clutch is engaged, the rotational speed of the engine is adjusted to match the rotational speed of the drive wheel with the rotational speed of the engine, and the clutch is gradually engaged. Countermeasures are conceivable. And
From the viewpoint of protecting the clutch and stabilizing the running, it is desirable that the rotational speeds on both sides of the clutch be made substantially the same, and the clutch should be fastened as slowly as possible.

However, how much the rotational speeds on both sides of the clutch need to be matched, and how slowly the clutch should be engaged differ depending on the running state of the vehicle. And like during acceleration,
When the driving force must be transmitted to the driving wheels early, there is a problem that the acceleration performance required by the driver cannot be obtained if the above-described matching of the rotational speed and the time required for the clutch engagement are required. Was.

The present invention has been made in view of the above circumstances, and an object of the present invention is to protect a clutch interposed between an engine and driving wheels while maintaining running performance. It is in.

[0009]

According to the present invention, the control for engaging the clutch means is changed in accordance with the running state.

More specifically, a first solution taken by the present invention is an engine, an output shaft connected to the engine via clutch means, a generator motor connected to the engine, The present invention is directed to a hybrid vehicle including a power storage unit for storing electric power generated by an electric motor, a traveling motor driven by the electric power of the power storage unit, and driving wheels connected to the traveling motor and an output shaft. A detecting means for detecting an input-side rotational speed on the engine side and an output-side rotational speed on the output shaft side of the clutch means; and an input-side rotational speed and an output-side rotational speed of the clutch means detected by the detecting means. After performing a rotation synchronizing operation of adjusting the number of revolutions of the engine by the generator motor so as to coincide with each other, the clutch means is engaged, and the running time is determined by a fastening time required from the start to completion of the engagement of the clutch means. And control means for changing the state according to the state quantity to be represented.

[0011] The second solution taken by the present invention is:
In the first solution, there is provided an automatic transmission which is interposed between an engine and an output shaft and switches between a neutral state in which an input side and an output side are disconnected and a shift state in which an input side and an output side are connected. The clutch means is an automatic transmission clutch means for switching the automatic transmission between a neutral state and a shift state.

Further, a third solution taken by the present invention is:
In the first or second solution means, the control means is configured to change the engagement time using the rate of change of the accelerator operation amount as a state quantity.

A fourth solution taken by the present invention is:
In the first or second solving means, the control means is configured to change the fastening time using the change rate of the output-side rotation speed detected by the detecting means as a state quantity.

Further, a fifth solution taken by the present invention is:
In the third or fourth solving means, the control means is configured to make the fastening time longer as the state quantity is smaller.

Further, a sixth solution taken by the present invention is:
In the third or fourth solving means, when the difference between the input-side rotational speed and the output-side rotational speed of the clutch device falls within a predetermined rotation allowable range, the control device determines that the two rotational speeds coincide with each other and engages the clutch device. In addition, the smaller the amount of state, the narrower the allowable rotation range.

Further, a seventh solution taken by the present invention is:
In the third or fourth solving means, when the state quantity becomes equal to or more than a predetermined value, the control means controls the input-side rotation speed of the clutch means to be higher than the output-side rotation speed by a predetermined rotation speed in the rotation synchronization operation. The engine speed is controlled and the fastening time is shortened.

An eighth solution taken by the present invention is:
In the first or second solving means, a torque converter is interposed between the engine and the clutch means, and the control means determines that a difference between the input-side rotation speed and the output-side rotation speed of the clutch means is within a predetermined rotation allowable range. When the torque converter falls within the range, the clutch means is engaged assuming that the two rotational speeds coincide with each other. If the torque converter is in a lock-up state, the allowable rotation range is narrowed and the engagement time is lengthened.

In the first solution, the driving force of the traveling motor is transmitted to the driving wheels, while when the clutch is engaged, the driving force of the engine is also transmitted to the driving wheels. Then, the vehicle travels by transmitting one or both driving forces of the traveling motor and the engine to the driving wheels. The generator motor is driven by the engine to generate electric power, and the generated electric power is stored in a power storage unit and used for driving a traveling motor or the like.

In the hybrid vehicle, the clutch means is switched on and off while the vehicle is running to switch the drive source. In particular, when engaging the clutch means, the control means performs the rotation synchronization operation and then engages the clutch means.
That is, the control means controls the rotation speed of the engine by the generator motor, and engages the clutch means after matching the input rotation speed and the output rotation speed of the clutch means.
At that time, the engagement time of the clutch means is appropriately changed according to the running state. The change of the fastening time is performed based on the state quantity representing the running state.

In the second solution, the clutch for the automatic transmission constituting the automatic transmission also functions as a clutch for intermittently connecting the engine and the output shaft.

In the third solution, the engagement time of the clutch means is changed in accordance with the rate of change of the accelerator operation amount.

In the fourth solution, the engagement time of the clutch means is changed in accordance with the rate of change of the output rotation speed detected by the detection means.

In the fifth solution, the smaller the state quantity, which is the rate of change of the accelerator operation amount or the rate of change of the output-side rotational speed, that is, the lower the required degree of acceleration and the closer the vehicle is to steady running, the shorter the engagement time. And slowly tighten the clutch means.

In the sixth solution, when the difference between the input-side rotation speed and the output-side rotation speed of the clutch device falls within the allowable rotation range, the clutch device is engaged. At this time, the smaller the state quantity, that is, the lower the degree of demand for acceleration and the closer to steady running, the narrower the allowable rotation range. Is executed.

In the seventh solution, when the state quantity is equal to or more than a predetermined value, that is, when the demand for acceleration is high,
During the rotation synchronizing operation, the engine speed is controlled so that the input side speed is slightly higher than the output side speed, and then the engagement time is shortened and the clutch means is quickly engaged.

In the above-mentioned eighth solution, the clutch device is engaged when the difference between the input-side rotation speed and the output-side rotation speed of the clutch device is within the rotation allowable range. At this time, the allowable rotation range and the engagement time are changed depending on whether or not the torque converter is in the lockup state. Here, when the torque converter is in the lock-up state, the input side and the output side of the torque converter are in a directly connected state. Therefore, if there is a difference between the input side rotation number and the output side rotation number of the clutch means, this rotation number The difference cannot be absorbed by the torque converter.
Therefore, when the torque converter is locked up,
The clutch means is fastened after narrowing the allowable rotation range so as to match the input side speed and the output side speed as much as possible, and the clutch time is lengthened and the clutch time is slowly engaged.

[0027]

Therefore, according to the above-described means, it is possible to appropriately change the engagement time of the clutch means according to the running state, and to protect the clutch means while maintaining the running performance. Specifically, for example, when it is not necessary to increase the driving force in a short time as in the case of steady running or gentle acceleration, the input-side rotation speed and the output-side rotation speed of the clutch unit should be matched as much as possible. Extend the engagement time and loosely engage the clutch means. As a result, the load on the clutch means at the time of engagement can be reduced, and damage to the clutch means can be prevented. On the other hand, when it is necessary to increase the driving force in a short time, such as when suddenly starting or rapidly accelerating, the difference between the two rotation speeds is reduced to some extent by matching the input rotation speed and the output rotation speed. If this is the case, thereafter, the engagement time is shortened and the clutch means is quickly engaged. As a result, the driving force transmitted to the driving wheels can be increased in a short time, and sufficient acceleration performance can be obtained.

In the second solution, the clutch for the automatic transmission constituting the automatic transmission also serves as the clutch for intermittently connecting the engine and the output shaft. Here, the clutch means for the automatic transmission has a lower clutch capacity than a dedicated clutch for intermittently transmitting and receiving large power. Therefore, switching from the neutral state to the shift state in a state where the rotational speed difference between the input side and the output side is large is not assumed, and if the switching is performed in such a state, it is easily damaged. On the other hand, in this solution,
Since the engagement time of the clutch means is changed according to the running state, even in this case, damage to the automatic transmission can be reliably prevented. Further, the reliability of the automatic transmission can be maintained while also serving as the clutch means. Therefore, there is no need to provide an independent clutch between the engine and the output shaft, and the configuration can be simplified. .

According to the seventh aspect, the engine speed is controlled so that the input side speed is higher than the output side speed, so that the driving force of the engine is maintained even while the clutch means is engaged. Can be transmitted to the driving wheels, and the driving force to the driving wheels can be quickly increased to improve the acceleration performance.

Further, according to the eighth aspect of the present invention, even when the load on the clutch means at the time of engagement due to the difference between the input-side rotational speed and the output-side rotational speed is large when the torque converter is in the lock-up state, the clutch means is not required. Protection can be achieved, and damage to the clutch means can be reliably prevented and reliability can be improved.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the mechanical configuration of the hybrid vehicle according to the present embodiment.

As shown in FIG. 1, the hybrid vehicle according to the present embodiment includes, as a power unit for generating a driving force, a traveling motor 2 driven by electric power supplied from a battery 3 serving as a power storage means, a gasoline or the like. Travels using the engine 1 driven by the explosive force of the liquid fuel of the vehicle, and travels only by the travel motor 2, travels only by the engine 1, or travels with the travel motor 2 according to the travel state of the vehicle described later. Running by both of the engines 1 is realized.

The engine 1 is connected to driving wheels 9 and 10 via a torque converter 5 and an automatic transmission 7.
The driving force of the engine 1 is transmitted from the output shaft 12 directly connected to the output side of the automatic transmission 7 to the driving wheels 9 and 10 via the gear train 11 and the differential mechanism 8. Further, the engine 1 has a generator motor 4 for charging the battery 3.
Drive.

Although not shown, the torque converter 5 has a lock-up clutch as a lock-up mechanism, and is configured so that the lock-up clutch is engaged and the lock-up is released, and the lock-up clutch is released when the lock-up clutch is released. ing.

Although not shown, the automatic transmission 7 is a four-speed transmission composed of components such as a planetary gear mechanism, a multi-plate clutch, a brake, and a one-way clutch. The automatic transmission 7 is provided with a neutral range (hereinafter, referred to as a “neutral range”) in which the input side and the output side are disconnected due to intermittent operation of a multi-plate clutch.
N range) and 1 where the input side and the output side are connected.
It is configured to switch to each speed range from the first speed to the fourth speed. The automatic transmission 7 functions as a transmission, and switches between the N range and the shift range to perform intermittent connection between the engine 1 and the drive wheels 9 and 10. An automatic transmission clutch means such as a multi-plate clutch for switching the automatic transmission 7 between the N range and the shift range constitutes a clutch means for intermittently connecting the engine 1 and the output shaft 12.

The traveling motor 2 is driven by electric power supplied from the battery 3, and transmits a driving force to driving wheels 9, 10 via a gear train 11. The traveling motor 2 is driven by the driving wheels 9 and 10 when the vehicle decelerates, and converts the kinetic energy of the vehicle into electric power and supplies it to the battery 3.

The generator motor 4 is driven by the engine 1 to generate electric power, and supplies electric power to the battery 3. The generator motor 4 receives electric power from the battery 3 when the engine 1 starts, and causes the engine 1 to crank.

The engine 1 is mounted, for example, of a type that delays the closing timing of a fuel-efficient valve. The traveling motor 2 is, for example, an IPM synchronous motor having a maximum output of 20 kW, and the generator motor 4 is, for example. Maximum output 1
A battery of 0 KW is used, and a nickel hydrogen battery having a maximum output of 30 KW is mounted as the battery 3, for example.

The overall control ECU 100 includes a CPU, an RO,
M, RAM, an interface circuit, an inverter circuit, etc., control the ignition timing and fuel injection amount of the engine 1, etc., control the output and rotation speed of the traveling motor 2 and the generator motor 4, and lock the torque converter 5. The control unit controls the up control, the control of the automatic transmission 7, the charging and discharging of the battery 3, and the like.

The overall control ECU 100 receives the number of revolutions of the crankshaft of the engine 1 and the number of revolutions of the traveling motor 2. Then, the overall control ECU 100 determines the input-side and output-side shaft rotation speeds of the automatic transmission 7 based on the input both rotation speeds, taking into account the speed ratio of the automatic transmission 7 and the gear ratio of the gear train 11. It is configured to calculate. That is, the overall control ECU 100
The detection means for detecting the input-side rotation speed and the output-side rotation speed of the automatic transmission 7 is configured.

Further, the general control ECU 100 is configured to shift the speed of the automatic transmission 7 according to a shift schedule as shown in FIG. This shift schedule is represented by the relationship between the vehicle speed and the accelerator pedal depression amount, and three shift lines are defined corresponding to the 4-speed automatic transmission 7. Then, when the vehicle crosses the speed change line, the speed of the automatic transmission 7 is changed. This shift schedule
The rotation speed of the engine 1 is determined so as to be in the range of the rotation speed with the highest efficiency of the engine 1 in relation to the vehicle speed.

Further, as indicated by hatching in FIG. 2, a predetermined lock-up region is defined, and the torque converter 5 is locked up in this lock-up region. That is, while the lock-up region is limited to a region where no shift is performed in a vehicle with only the engine 1, the lock-up region is expanded to a region where a shift is performed in the present hybrid vehicle. This is because, in the present hybrid vehicle, the change in the driving force of the engine 1 due to the shift can be absorbed by the driving force of the traveling motor 2, and the shift can be performed without causing the shift shock even in the locked-up state of the torque converter 5. It is.

-Driving Operation-Next, referring to Table 1 below, the engine 1, the generator motor 4, the traveling motor 2 and the battery 3 under the main conditions
Will be described. In Table 1, "power running" means a state in which a driving torque is being output.

[0045]

[Table 1]

[During stop] As shown in Table 1, when the vehicle is stopped, the engine 1, the generator motor 4 and the traveling motor 2 are stopped. However, the engine 1 is operated when the engine is cold and when the charged amount of the battery is low, and the generator motor 4 is driven to generate power during the operation of the engine and charges the battery 3.

[Slow Start] As shown in Table 1, during slow start, the engine 1 and the generator motor 4 are stopped, and the traveling motor 2 outputs a driving torque.

[Sudden Start] As shown in Table 1, at the time of sudden start, the traveling motor 2 outputs a driving torque, and the engine 1 is operated at a high output after starting. The battery 3 discharges to the traveling motor 2. Although the generator motor 4 is stopped after the engine 1 is started here, the generator motor 4 may continuously output the driving torque.

[At the time of engine start] As shown in Table 1, at the time of engine start, the generator motor 4 outputs driving torque to crank the engine 1 and the engine 1 is started. Battery 3 discharges to generator motor 4.

[During steady low-load running] As shown in Table 1,
During steady low-load traveling, the engine 1 and the generator motor 4 are stopped, and the traveling motor 2 outputs driving torque. The battery 3 discharges to the traveling motor 2. However, the engine 1 is operated when the engine is cold and when the charged amount of the battery is low, and the generator motor 4 is driven to generate power during the operation of the engine and charges the battery 3. In the present embodiment, the state of steady low-load running is limited to the case where the vehicle speed is 20 km / h or less. Therefore, when the vehicle speed exceeds 20 km / h during steady running, the operation shifts from low load operation to medium load operation.

[During Steady Medium Load Running] As shown in Table 1,
During normal medium-load running, the traveling motor 2 is set to no output, the engine 1 is operated in a high-efficiency region, the battery 3 does not discharge to the traveling motor 2, and the generator motor 4 charges the battery 3. .

[During steady high-load running] As shown in Table 1,
At the time of steady high load running, the engine 1 is operated at high output,
The generator motor 4 and the traveling motor 2 output driving torque. The battery 3 discharges to the generator motor 4 and the traveling motor 2. However, the generator motor 4 charges the battery 3 when the battery charge is low.

[During Rapid Acceleration] As shown in Table 1, during rapid acceleration, the engine 1 is operated at high output, and the generator motor 4 and the traveling motor 2 output driving torque for traveling.
The battery 3 discharges to the generator motor 4 and the traveling motor 2.

At the time of deceleration (at the time of regenerative braking) As shown in Table 1, at the time of deceleration, the engine 1 and the generator motor 4 are stopped, and the traveling motor 2 regenerates electric power as a generator to generate the battery 3. Charge.

-Setting of fastening conditions- In the hybrid vehicle of this embodiment, the traveling motor 2
In some cases, the torque of the engine 1 may be transmitted to the driving wheels 9 and 10 from the middle while the vehicle is running only with the driving torque of. Specifically, this corresponds to the above-described sudden start or a transition from steady low-load running to steady medium-load running, steady high-load running, or sudden acceleration. In this case, the general control ECU 1
00 performs predetermined engine engagement control after the engagement condition setting operation. In addition, as part of the engine engagement control, the overall control ECU 100 controls the generator motor 4 so that the input-side rotation speed on the engine side and the output shaft-side rotation speed on the output shaft side of the automatic transmission 7 match. A rotation synchronization operation for adjusting the number of rotations is performed.

First, the fastening condition setting operation will be described with reference to FIGS.
This will be described with reference to FIG. In this engagement condition setting operation, selection and correction of the engagement time and selection of the target engine speed difference are performed in accordance with the running state.

The above-mentioned engagement time represents the time from the start of the engagement of the clutch means to the completion thereof. here,
In the present embodiment, as described above, clutch means for an automatic transmission such as a multi-plate clutch constituting the automatic transmission 7 constitutes the clutch means. Therefore, the engagement time means the time from the start of switching from the N range to the shift range in the automatic transmission 7 to the completion thereof. Then, as shown in FIG. 4, T1, T2, T
Three values of 3 are set in advance, and are selected from these. The magnitude relationship between the three values of the fastening time is as follows:
It is set so that T1 <T2 <T3.

The target rotational speed difference is, as shown in FIG.
Three values of R1, R2, and R3 are set in advance as the target rotational speed difference. Then, a selection is made from these three values. Note that the magnitude relationship between the three values of the target rotational speed difference is set so that R1>R2> R3. R3 is set to zero. In the rotation synchronizing operation, the engine speed is controlled so that the input side speed in the automatic transmission 7 becomes higher than the output side speed by the target speed difference. This rotation synchronization operation will be described later.

The above-mentioned fastening time is corrected by multiplying the selected fastening time by a correction coefficient β. This correction coefficient β is predetermined in relation to the rate of change of the accelerator pedal depression amount, as shown in FIG. That is, when the change amount is smaller than the predetermined range, the fastening time selected as β = 1 is not changed. On the other hand, when the amount of change is within the predetermined range, the value of β is reduced as the amount of change increases, and the selected fastening time is shortened.
If the variation exceeds a predetermined range, the value of β is kept constant, and no further shortening of the fastening time is performed.

Next, the details of the fastening condition setting operation will be described with reference to the flowchart of FIG.

At step ST1, it is determined whether or not there is a request for sudden start. That is, when the accelerator is suddenly depressed while the vehicle is stopped, it is determined that rapid start is required, and the process proceeds to step ST2. On the other hand, if it is determined that sudden start is not requested, the process proceeds to step ST4. The presence or absence of a request for sudden start may be determined based on the rate of change in the output shaft speed. That is, if the rate of increase in the output shaft rotation speed is large, it may be determined that there is a request for sudden start, and if the rate of increase in harm is small, it may be determined that there is no request for sudden start.

If a sudden start is requested, step ST2
, The engagement time T1 and the target rotational speed difference R1 are selected,
Move to step ST3. In step ST3, a correction coefficient β is determined according to the accelerator pedal depression amount, and the correction coefficient β is multiplied by the engagement time T1 to calculate a corrected engagement time T1 ′.
Therefore, if there is a request for a sudden start, the fastening time is shortened as much as possible, and the difference in the target rotational speed is increased as much as possible.

If no sudden start is requested, step
In ST4, it is determined whether or not torque converter 5 is in a lock-up state. If it is not in the lockup state, the process proceeds to step ST5, and if it is in the lockup state, the process proceeds to step ST7.

At step ST5, the engagement time T2 and the target rotational speed difference R2 are selected, and the routine goes to step ST6. Steps
In ST6, a correction coefficient β is determined according to the accelerator pedal depression amount, and the correction coefficient β is multiplied by the engagement time T2 to calculate a corrected engagement time T2 ′. Therefore, unless the lock-up state is established, the engagement time and the target rotational speed difference are set to intermediate values.

On the other hand, in step ST7, the engagement time T3 and the target rotational speed difference R3 are selected, and the routine goes to step ST8. In step ST8, the correction of the engagement time is prohibited.

Accordingly, in the lock-up state, the fastening time is made as long as possible and the difference in the target rotational speed is made as small as possible.

-Operation at Engine Engagement- As described above, the overall control ECU 100 performs predetermined engine engagement control after the engagement condition setting operation.

First, the outline of the engine engagement control will be described with reference to the time chart of FIG. FIG. 7 shows a state in which the vehicle starts from the stop state, gradually accelerates, and shifts from the steady low-load running to the steady medium-load running. At time t1, the vehicle starts slowly and enters the steady low-load running state described above. Then, only the traveling motor 2 generates a driving force, and the vehicle speed gradually increases.

Thereafter, at time t2, the vehicle speed becomes 20
When the engine speed exceeds km, the engine 1 is driven by the generator motor 4 in order to shift from steady low load running to steady medium load running.
To crank. When the engine 1 starts, at time t3
, The feedback control for the generator motor 4 is started. Thereafter, until the time t4, the throttle opening is maintained at the predetermined opening to generate a predetermined torque in the engine 1, while the generator motor 4 acts as a generator to apply a load to the engine 1 and control this load. To control the engine speed.

When the engine speed matches the target engine speed at time t4, the automatic transmission 7 is switched from the N range to the first speed range. In this state, the engine 1
Is transmitted to the drive wheels 9 and 10. For this reason, at time t4, the automatic transmission 7 is switched and the driving force of the traveling motor 2 is reduced, so that the driving force transmitted to the driving wheels 9 and 10 is kept constant. After that, the traveling is continued only by the driving force of the engine 1.

Next, details of the engine engagement control will be described with reference to the flowcharts of FIGS.

First, in step ST10, the vehicle speed, the accelerator pedal depression amount, the rotation speed of the traveling motor 2 and the engine 1
Read the rotation speed of. Then, the rotational speed of the output shaft 12 is calculated by multiplying the rotational speed of the traveling motor 2 by the gear ratio of the gear train 11, and the process proceeds to step ST11.

In step ST11, the engine 1 is set on the basis of the vehicle speed, the accelerator pedal depression amount, and the rate of change of the accelerator pedal depression amount.
It is determined whether or not starting is required. In other words, when the vehicle speed exceeds 20 km / h and the vehicle shifts to the above-described steady medium load running, or when the accelerator is suddenly depressed and sudden acceleration or sudden start is required, the engine 1 needs to be started. Judge and proceed to step ST12. On the other hand, if the start of the engine 1 is unnecessary, the control returns to the normal control.

In step ST12, the speed range of the automatic transmission 7 is selected based on the shift schedule, and the target engine speed is calculated by multiplying the output shaft speed by the speed ratio of the speed range. When the rotation speed of the engine 1 reaches the target engine rotation speed, the input rotation speed and the output rotation speed of the automatic transmission 7 match. Note that this step ST
From 12 onward, the change of the once selected shift range is prohibited until the shift of the automatic transmission 7 is completed.

In the following step ST13, it is determined whether or not there is a request for sudden start. That is, when the accelerator is suddenly depressed while the vehicle is stopped, it is determined that rapid start is required, and the process proceeds to step ST24. On the other hand, if it is determined that the sudden start is not requested, the process proceeds to step ST14. The presence or absence of a request for sudden start may be determined based on the rate of change in the output shaft speed. That is, if the rate of increase in the output shaft rotation speed is large, it may be determined that there is a request for sudden start, and if the rate of increase in harm is small, it may be determined that there is no request for sudden start.

When there is a request for sudden start, first, at step ST
At 24, control for releasing lockup of the torque converter 5 is performed. The reason for releasing the lock-up is to transmit a larger driving force to the driving wheels 9 and 10 by utilizing the torque amplifying action of the torque converter 5.

In the following step ST25, the generator motor 4
Power is supplied from the battery 3 to the engine 1 and the engine 1 is cranked by the generator motor 4 to start the engine 1. When the engine speed reaches 1000 rpm, the process proceeds to step ST26.

At step ST26, fuel injection and ignition are performed on the engine 1 to try to start the engine 1. Then, it is confirmed whether or not the engine 1 has been started, and if it has been started, the process proceeds to step ST27. On the other hand, if the engine 1 has not been started, the process proceeds to engine start control and the engine 1
Try to start more. This engine start control will be described later. Note that whether or not the engine 1 has started is determined based on the current supplied to the generator motor 4. That is, if the current to the generator motor 4 has decreased, it is determined that the engine 1 has started, and if not, it is determined that the engine 1 has not started.

In step ST27, the throttle is fully opened in order to maximize the torque of the engine 1, and the rotation synchronous operation is performed with the torque generated by the generator motor 4 being maximized. That is, in the sudden start state, the torque of the traveling motor 2 is maximized and the vehicle has already started to move,
Even if the throttle is opened, the engine speed does not rise immediately. Therefore, the engine 1 is driven with the torque of the generator motor 4 being maximized, and the input and output speeds of the automatic transmission 7 are matched. At this time, the input-side rotational speed of the automatic transmission 7 is set to be higher than the output-side rotational speed by the target rotational speed difference R1.

Here, if only a short time has passed since the driver issued a request for a sudden start, the vehicle speed has not yet increased so much.
And if the generator motor 4 is set to the maximum output, the automatic transmission 7
It can be considered that the difference in rotation speed between the input side and the output side is not so large. Further, a slight difference in the number of rotations can be absorbed by the torque converter 5.

Therefore, in step ST27, after the throttle is fully opened and the torque of the generator motor 4 is maximized, the automatic transmission 7 is quickly shifted from the N range to the first speed range without a time delay. Specifically, the shift from the N range to the first speed range is completed with the corrected engagement time T1 '. The reason why the shift is completed in as short a time as possible is that if the shift requires a long time, the difference in the number of revolutions on both sides of the automatic transmission 7 increases. After the shift is completed, the driving wheels 9 and 10 are driven by the engine 1 and the traveling motor 2, while the generator motor 4 is stopped. The torque of the generator motor 4 may be transmitted to the drive wheels 9 and 10 without stopping the generator motor 4. In this case, a larger driving force can be transmitted to the drive wheels 9 and 10.

If there is no sudden start request in step ST13, it is determined in step ST14 whether there is a sudden acceleration request. In other words, if the accelerator is suddenly depressed while the vehicle is running, it is determined that rapid acceleration is required, and the process proceeds to step ST15. On the other hand, if it is determined that rapid acceleration has not been requested, the process proceeds to step ST30. The presence or absence of a request for rapid acceleration may be determined based on the rate of change in the output shaft speed. That is, if the rate of increase in the output shaft rotation speed is large, it may be determined that there is a request for rapid acceleration, and if the rate of increase is small, it may be determined that there is no request for rapid acceleration.

When there is a request for rapid acceleration, first, in step ST
At 15, control for releasing the lockup of the torque converter 5 is performed. The lock-up is released in order to obtain the torque amplifying effect of the torque converter 5 as in the case of step ST24.

In the following step ST16, the above-mentioned step ST16 is executed.
The engine 1 is cranked by the generator motor 4 corresponding to step 25, and when the engine speed reaches 1000 rpm, the process proceeds to step ST17.

At step ST17, at step ST26
The operation for starting the engine 1 is performed in response to (1). If the engine has been started, the process proceeds to step ST18, and if not, the process proceeds to engine start control.

In step ST18, the output torque is calculated by adding the additional torque α2 to the target torque. This target torque is calculated based on the vehicle speed read in step ST10 and the step ST10.
The torque that must be generated by the engine 1 in order to run only on the engine 1 at the speed ratio of the shift range of the automatic transmission 7 selected at 12. On the other hand, the added torque α2 is set in advance according to the traveling state.
Then, control is performed to generate an output torque for the engine 1. Specifically, the throttle is set to a predetermined opening, and the throttle opening is kept constant.

In the following step ST19, the traveling motor 2
Is controlled to keep the generated torque constant, and this state is maintained until the shift of the automatic transmission 7 is completed. In other words, until the shift is completed, the accelerator pedal depression amount,
That is, the torque of the traveling motor 2 is kept constant irrespective of the driver's intention. The reason for this is to keep the output shaft rotation speed or the rate of change of the rotation speed constant, and to surely adjust the engine rotation speed corresponding to the output shaft rotation speed.

In the following step ST20, a rotation synchronization operation is performed. At this time, the target engine speed calculated in step ST12 is corrected to a value such that the input speed of the automatic transmission 7 becomes higher than the output speed by the target speed difference R2. Thereafter, the generator motor 4 operates as a generator to apply a load to the engine 1, and the amount of the load is feedback-controlled with respect to the engine speed so that the engine speed becomes the corrected target engine speed. I do. This control is performed for a predetermined time, and the routine goes to Step ST21.

At step ST21, a shift operation for switching the automatic transmission 7 from the N range to the shift range selected at step ST12 is started. Further, the shift from the N range to the shift range is completed with the corrected engagement time T2 '. At this time, if the rotation synchronization operation is performed for a certain period of time, the rotation speed difference between the actual engine rotation speed and the target engine rotation speed is sufficiently small, and the lock-up of the torque converter 5 is released in step ST15. As a result, even if there is a certain difference in the number of revolutions, the torque converter 5 can absorb the difference, so that the automatic transmission 7 performs the shifting operation.

In the following step ST22, it is confirmed that the switching to the shift range has been completed, and then the operation proceeds to step ST23. Therefore, at the time of moving to step ST23, the driving force of the engine 1 is transmitted to the driving wheels 9 and 10.

In step ST23, the load applied to the engine 1 by the generator motor 4 is set to zero, and the throttle opening of the engine 1 is controlled in accordance with the amount of depression of the accelerator. Then, the engine 1 and the traveling motor 2
Is transmitted to the driving wheels 9 and 10 to perform rapid acceleration.

If there is no request for rapid acceleration in step ST14, the process proceeds to step ST30 shown in FIG. This step
In ST30, the engine 1 is cranked by the generator motor 4 corresponding to step ST25, and when the engine speed reaches 1000 rpm, the process proceeds to step ST31.

At step ST31, at step ST26
The operation for starting the engine 1 is performed in response to (1). If the engine has been started, the process proceeds to step ST32. If not, the process proceeds to engine start control.

In step ST32, it is determined whether or not the charged amount of the battery 3 is small.
The process proceeds to ST33, and if less than the predetermined value, the process proceeds to step ST34.

At step ST33, at step ST18
, The output torque is calculated by adding the additional torque α to the target torque. This additional torque α is set to a value smaller than the additional torque α2 in step ST18. And
The predetermined throttle opening is maintained so that the engine 1 generates the calculated output torque, and the process proceeds to step ST35.

On the other hand, in step ST34,
The output torque is calculated by adding the additional torque α1 to the target torque corresponding to ST18. The additional torque α1 is smaller than the additional torque α2 in step ST18 and larger than the additional torque α in step ST33.
Then, the predetermined throttle opening is maintained so that the engine 1 generates the calculated output torque, and the process proceeds to step ST35.

That is, while the additional torque α and the additional torque α1 are selectively used depending on the amount of charge of the battery 3 (see steps ST33 and ST34), the additional torque α2 and the additional torques α and α1 are selectively used depending on whether or not a rapid acceleration is requested. (See steps ST18, ST33, ST34).

In step ST35, the torque converter 5
Is in a lockup state. If it is in the lockup state, the process proceeds to step ST36, while if the lockup is released, the process proceeds to step ST40.

If the torque converter 5 is in the lock-up state, in steps ST36 to ST38, the engine 1
The rotation synchronizing operation is performed until it can be considered that the actual engine speed and the target engine speed calculated in step ST12 almost completely match. This is because the engine 1 and the input side of the automatic transmission 7 are directly connected in the lock-up state of the torque converter 5, and unless the actual engine speed of the engine 1 substantially matches the target engine speed, the automatic This is because a shock may occur when the transmission 7 is switched from the N range to the shift range, or the automatic transmission 7 may be damaged.

In step ST36, the generator motor 4 operates as a generator to apply a load to the engine 1, and the amount of the load is adjusted so that the rotation speed of the engine 1 becomes the target engine rotation speed calculated in step ST12. Feedback control is performed on the rotation speed. Although the target rotational speed difference R3 is selected in the engagement condition setting operation, since the value of R3 is zero, control is performed so that the rotational speed of the engine 1 becomes the target engine rotational speed in step ST12.

On the other hand, in step ST37, the driving force of the traveling motor 2 is controlled so that the acceleration of the vehicle body becomes constant. Specifically, control is performed so that the rate of change of the output shaft speed is constant. Then, in step ST38, the states of steps ST36 and ST37 are held until it can be considered that the actual rotation speed of the engine 1 substantially matches the target engine rotation speed.
Move on to ST39.

In step ST39, corresponding to step ST21, a shift operation for switching the automatic transmission 7 from the N range to the shift range selected in step ST12 is started. At this time, the shift from the N range to the shift range is completed in the engagement time T3. Therefore, the shift from the N range to the shift range is performed as slowly as possible.

If the torque converter 5 is not in the lock-up state, the process proceeds to step ST40 where the above-described step ST20
Perform the rotation synchronization operation corresponding to. Specifically, feedback control is performed on the amount of load that the generator motor 4 applies to the engine 1 so that the rotation speed of the engine 1 becomes the corrected target engine rotation speed.

That is, in steps ST35 to ST41, whether or not the torque converter 5 is in the lock-up state is determined.
The degree to which the actual engine speed of the engine 1 matches the target engine speed is changed.

At step ST39, corresponding to step ST21, a shift operation for switching the automatic transmission 7 from the N range to the shift range selected at step ST12 is started. At this time, the shift from the N range to the shift range is completed with the corrected engagement time T2 '.

In step ST42 following step ST39 or step ST41, it is confirmed whether or not switching to the shift range has been completed, and the routine proceeds to step ST43. Also,
During the speed change operation, the driving force transmitted from the engine 1 to the driving wheels 9 and 10 increases. However, the driving force of the traveling motor 2 is reduced accordingly, and To maintain a constant driving force.

In step ST43, the load applied to the engine 1 by the generator motor 4 and the driving force of the traveling motor 2 are set to zero, and the throttle opening of the engine 1 is controlled in accordance with the amount of depression of the accelerator. Do. Note that the load on the engine 1 by the generator motor 4 may not be set to zero, and the output of the engine 1 may be controlled to be relatively large to continue the power generation by the generator motor 4.

-Operation for Starting Engine-At the time of the above-described engine engagement control, the above-described steps ST17 and ST
26, when the engine 1 cannot be started in ST31, the engine start control shown in the flowchart of FIG. 10 is performed.

In step ST50, the power supplied from the battery 3 to the generator motor 4 is increased to increase the engine speed. And the engine speed is 1500 rpm
Is reached, the process proceeds to step ST51.

At step ST51, fuel injection and ignition are performed on the engine 1 to try to start the engine 1. Then, it is confirmed whether or not the engine 1 has been started. If the engine 1 has been started, the process proceeds to step ST57, returns to the original control flow, and proceeds from step ST17, ST26, ST31 to the next step. On the other hand, if the engine 1 has not been started, the process proceeds to step ST52.

In step ST52, the current supplied from the battery 3 to the traveling motor 2 is reduced. This is because the current that can be discharged from the battery 3 has an upper limit, so that the current to the traction motor 2 is reduced and the current to the generator motor 4 that cranks the engine 1 is secured.

At the following step ST53, at step ST51
Attempt to start the engine 1 in the same manner as described above. Then, if the engine 1 is started, the process proceeds to step ST57 and returns to the original control flow, while if the engine 1 is not started, the process proceeds to step ST54.

In step ST54, the rotation speed of the engine 1 and the target engine rotation speed in step ST12 are matched only by the driving force of the generator motor 4, and then the automatic transmission 7
Is switched from the N range to the second speed range. Then, the engine 1 is rotated not only by the driving force of the generator motor 4 but also by the driving force of the traveling motor 2 and the inertial force of the vehicle body. At the next step ST55, the engine 1 is tried to start.
That is, in steps ST54 and ST55, a so-called "push-off" is attempted.

At this time, the driving force of the traveling motor 2 is increased in accordance with the switching of the automatic transmission 7 from the N range to the second speed range, and control is performed to keep the traveling state constant.
Here, if the driving force of the traveling motor 2 remains constant, the vehicle will decelerate if the engine 1 is directly connected to the driving wheels 9 and 10. On the other hand, the state of the vehicle is kept constant by increasing the driving force of the traveling motor 2 so that the driver does not feel uncomfortable.

In step ST55, if the engine 1 is started, the process proceeds to step ST57 and returns to the original control flow, while if the engine 1 is not started, the process proceeds to step ST57.
Move to 56.

In step ST56, the driver is informed by a warning lamp or the like that the engine 1 could not be started, and control is performed to emphasize the regeneration by the traveling motor 2 in order to secure the charged amount of the battery 3.

-Effects of Embodiment- According to the present embodiment, the engagement time of the clutch means, that is, the time required for shifting of the automatic transmission 7 is appropriately changed according to the running state, and the automatic shifting is performed while maintaining the running performance. The machine 7 can be protected. In other words, when it is not necessary to increase the driving force in a short time as in the case of steady running or moderate acceleration, the input rotation speed and the output rotation speed of the automatic transmission 7 should be matched as much as possible, and And the shift of the automatic transmission 7 is performed slowly. As a result, the load on the automatic transmission 7 during shifting can be reduced, and damage to the automatic transmission 7 can be prevented. On the other hand, when it is necessary to increase the driving force in a short time, such as when suddenly starting or rapidly accelerating, the difference between the two rotation speeds is reduced to some extent by matching the input rotation speed and the output rotation speed. For example, after that, the automatic transmission 7 is quickly shifted by shortening the engagement time. As a result, the driving force transmitted to the driving wheels can be increased in a short time, and sufficient acceleration performance can be obtained.

In this embodiment, the multi-plate clutch or the like constituting the automatic transmission 7 also serves as a clutch means for intermittently connecting the engine 1 and the output shaft 12. Here, the above-mentioned multi-plate clutch or the like has a lower clutch capacity than a dedicated clutch for the purpose of intermittent transmission of large power. Therefore, if the range is changed from the N range to the shift range in a state where the rotational speed difference between the input side and the output side is large, it is easily damaged. On the other hand, in the present embodiment, the engagement time of the clutch means, that is, the time required for shifting of the automatic transmission 7 is changed according to the running state, so that the damage of the automatic transmission 7 can be reliably prevented. Can be. Then, the reliability of the automatic transmission 7 can be maintained while also serving as the clutch means, and it is not necessary to provide an independent clutch between the engine 1 and the output shaft 12, and the configuration can be simplified. Become.

Further, since the engine speed is controlled so that the input side speed is higher than the output side speed, the driving force of the engine can be transmitted to the drive wheels even while the automatic transmission 7 is shifting. Thus, the driving force to the driving wheels can be quickly increased to improve the acceleration performance.

If the load on the automatic transmission 7 during shifting due to the difference between the input-side rotation speed and the output-side rotation speed is large when the torque converter 5 is locked up, the automatic transmission 7
The shift is made as slowly as possible. As a result, protection of the automatic transmission 7 can be achieved, and damage to the automatic transmission 7 can be reliably prevented and reliability can be improved.

[0121]

Other Embodiments of the Invention-First Modification-In the above embodiment, a clutch means for connecting and disconnecting between the engine 1 and the output shaft 12 is provided by an automatic transmission 7 such as a multi-plate clutch. Although the transmission clutch means is used, an independent clutch may be provided between the engine 1 and the output shaft 12.

Second Modification In the above embodiment, when calculating the target engine speed in the engine engagement control, the output shaft speed is multiplied by the speed ratio of the automatic transmission 7 (see step ST12). . However, in the state where the lock-up of the torque converter 5 is released, the slippage of the torque converter 5 causes the input speed of the automatic transmission 7 and the output speed of the automatic transmission 7 even if the engine speed matches the target engine speed. It does not always match the rotation speed. Therefore, when the torque converter 5 is in the non-lockup state, a value that takes into account the slippage of the torque converter 5 is added to the value obtained by multiplying the output shaft speed by the above-mentioned speed ratio, and the value after this correction is used as the target engine speed. Good.

-Third Modification- In the above embodiment, in the rotation synchronization operation in the engine fastening control, a load is applied to the engine 1 by the generator motor 4, and the load is controlled to control the engine speed. (Steps ST20, ST36, ST40)
reference). On the other hand, even after the engine 1 is started, the engine 1 may be rotationally driven by the generator motor 4 and the driving force of the generator motor 4 may be controlled to control the engine speed.

An outline of the engine engagement control in this case will be described with reference to a time chart of FIG.
This FIG. 11 shows, from the time when the vehicle slowly starts to accelerate, gradually accelerates to the time when the vehicle shifts from the steady low load running to the steady medium load running, as in the time chart of FIG.

When the vehicle starts at time t1, the vehicle gradually accelerates and the vehicle speed exceeds 20 km / h at time t2. Time t
In 2, the engine 1 is cranked by the generator motor 4 in order to shift from the steady low load running to the steady medium load running. When the engine 1 starts, the feedback control for the generator motor 4 starts at time t3. Thereafter, until time t4, the generator motor 4 continuously drives the engine 1 to rotate and controls the driving force of the generator motor 4 to control the engine speed.

When the engine speed matches the target engine speed at time t4, the automatic transmission 7 is switched from the N range to the first speed range. In this state, the engine 1
Is transmitted to the drive wheels 9 and 10. For this reason, at time t4, the automatic transmission 7 is switched and the driving force of the traveling motor 2 is reduced, so that the driving force transmitted to the driving wheels 9 and 10 is kept constant. After that, the traveling is continued only by the driving force of the engine 1.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a hybrid vehicle.

FIG. 2 is a diagram showing a relationship between a vehicle speed and an accelerator pedal depression amount, showing a shift schedule of an automatic transmission and a lock-up region of a torque converter.

FIG. 3 is a flowchart showing a fastening condition setting operation.

FIG. 4 is a relationship diagram showing a magnitude relationship between values of a fastening time.

FIG. 5 is a relationship diagram showing a magnitude relationship between values of a target rotation speed difference.

FIG. 6 is a diagram illustrating a relationship between a correction coefficient β for engagement time and an accelerator pedal depression amount.

FIG. 7 is a time chart showing an operation in engine engagement control.

FIG. 8 is a flowchart showing an operation in engine engagement control.

FIG. 9 is a flowchart showing an operation in engine engagement control.

FIG. 10 is a flowchart showing an operation in engine start control.

FIG. 11 is a diagram corresponding to FIG. 7 in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Running motor 3 Battery (power storage means) 4 Generator motor 5 Torque converter 7 Automatic transmission 12 Output shaft

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 29/00 F16H 61/02 29/02 B60K 9/00 Z F16H 61/02 // F16H 59:40 59 : 42 (72) Inventor Naoyuki Hikita 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima F-term in Mazda Co., Ltd. (Reference) AC15 AC18 AD00 AD01 AD02 AD04 AD10 AD12 AD30 AD31 AE02 AE03 AE04 AE07 AE09 AE32. CA05 CA15 EA02 EA03 EA06 FB33 GC13 GC43 GC44 GC46 HA02 HA06 HA17 HA19 LA01 5H115 PA08 PG04 PI16 PI22 PI29 PO17 PU10 PU22 PU24 PU25 QE01 QE08 QE10 QI0 4 QN03 QN06 QN12 RB08 RE01 RE02 RE05 SE05 SE08 TB01 TE02 TO22

Claims (8)

[Claims] 1. An engine, an output shaft connected to the engine via clutch means, a generator motor connected to the engine, power storage means for storing electric power generated by the generator motor, and A drive motor driven by the power of the means, a drive wheel connected to the drive motor and the output shaft, and an input-side rotation speed on the engine side and an output-side rotation speed on the output shaft side of the clutch means. And a rotation synchronization operation of adjusting the engine speed by the generator motor so that the input side speed and the output side speed of the clutch means detected by the detecting means match. Control means for engaging the clutch means and changing the engagement time required from the start to the completion of the engagement of the clutch means in accordance with the state quantity representing the running state. Hybrid vehicle. 2. The hybrid vehicle according to claim 1, wherein a neutral state is interposed between the engine and the output shaft and the input side and the output side are disconnected, and a shift state in which the input side and the output side are connected. A hybrid vehicle that is an automatic transmission clutch that switches the automatic transmission between a neutral state and a shift state. 3. The hybrid vehicle according to claim 1, wherein the control unit changes the engagement time using a rate of change of an accelerator operation amount as a state amount. 4. The hybrid vehicle according to claim 1, wherein the control unit is configured to change the engagement time using a change rate of the output-side rotation speed detected by the detection unit as a state quantity. . 5. The hybrid vehicle according to claim 3, wherein the control means is configured to make the engagement time longer as the state quantity is smaller. 6. The hybrid vehicle according to claim 3, wherein the control means determines that the two rotation speeds match when a difference between the input rotation speed and the output rotation speed of the clutch means falls within a predetermined rotation allowable range. A hybrid vehicle in which the clutch means is engaged and the allowable rotation range is narrowed as the state amount is small. 7. The hybrid vehicle according to claim 3, wherein when the state quantity is equal to or more than a predetermined value, the control means sets the input rotation speed of the clutch means to be smaller than the output rotation speed in the rotation synchronization operation. A hybrid vehicle configured to control the engine speed so as to increase the engine speed and shorten the engagement time. 8. The hybrid vehicle according to claim 1, further comprising: a torque converter interposed between the engine and the clutch means, wherein the control means controls an input rotation speed and an output rotation speed of the clutch means. When the difference is within a predetermined rotation allowable range, the clutch means is engaged as a coincidence of the two rotation speeds. If the torque converter is in a lockup state, the rotation allowable range is narrowed and the engagement time is lengthened. A hybrid vehicle that is made up.