JP4956789B2 - Inertial travel control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a powertrain control when a hybrid vehicle that can be driven not only by an engine but also by power from a motor / generator and enters an inertial traveling from a driving traveling with an accelerator opening being zero.

Conventionally, various types of hybrid control devices used in the hybrid vehicle as described above have been proposed, and one of them is known as described in Patent Document 1.
First, the power train of a hybrid vehicle to be controlled by this control device will be described. A power source is provided that is drivingly coupled to an engine and a motor / generator, and is locked up on a power transmission path between the power source and driving wheels. A torque converter with a mechanism and a transmission are inserted.
Then, during coasting of the vehicle (coast operation), the lockup mechanism is released and the engine is driven. If the drive wheel side (turbine) rotation speed of the lockup mechanism at this time is equal to or higher than the idle rotation speed of the engine, the target rotation speed of the motor / generator is set within a range equal to or lower than the drive wheel side rotation speed. On the other hand, when the rotational speed is lower than the idle speed, control is performed to set the target rotational speed of the motor / generator to the idle rotational speed.

JP 2004-66843 A

  By the way, in the transmission used for the hybrid vehicle as described above, in particular, when a general automatic transmission is used as the transmission, the transmission is provided for the purpose of eliminating a shift shock by a simple shift control. In many cases, it has a gear stage that transmits power through a one-way clutch.

In a state where the transmission has selected such a gear position, the driver depresses the accelerator pedal and is driving, and the one-way clutch is engaged to transmit power. In this state, when the driver releases the accelerator pedal, the hybrid vehicle starts coasting from driving. Then, the one-way clutch is disengaged due to idling during coasting, and the one-way clutch drive wheel side rotational speed is higher than the one-way clutch power source side rotational speed.

  During inertial running, the vehicle speed of the hybrid vehicle gradually decreases due to running resistance, so the one-way clutch drive wheel side rotation speed decreases with time. On the other hand, since the engine is maintained in the idling state, the one-way clutch power source side rotational speed does not become lower than the engine idle rotational speed. As a result, the one-way clutch is re-engaged for a while after the start of inertial running, and a one-way clutch engagement shock is generated. This engagement shock may impair the riding comfort performance of the hybrid vehicle.

  The present invention proposes an inertial traveling control device for a hybrid vehicle that can eliminate the one-way clutch engagement shock that occurs when inertial traveling continues for a while in the hybrid vehicle of the power train described above. For the purpose.

For this purpose, the inertial running control device for a hybrid vehicle according to the present invention is configured as described in claim 1.
First of all, to explain the premise hybrid vehicle,
A power source including an engine and a motor / generator, and a friction element that is in a state of fastening, slipping, or releasing according to a fastening force on a power transmission path from the power source to the driving wheel, and a plurality of friction elements A hybrid vehicle in which a transmission capable of selecting a gear position is inserted.

The present invention relates to such a hybrid vehicle,
In a state in which the transmission selects a gear stage that transmits power via a one-way clutch that enables transmission of driving torque from the power source side to the driving wheel side and cuts off transmission of torque from the driving wheel side to the power source side. When it is detected that the vehicle has entered inertia running regardless of the driving torque of the power source, the rotational speed of the power source is controlled so that the power source side rotational speed of the one-way clutch is lower than the driving wheel side rotational speed. A neutral state in which the driving torque of the power source is not transmitted while the friction element is fastened,
Under the neutral state, the fastening force of the friction element is reduced to prepare for shifting to the slip fastening state.

According to the inertial running control device for a hybrid vehicle according to the present invention described above,
While the one-way clutch is in the released state during inertial running, the friction element inserted between the power source consisting of the engine and motor / generator and the drive wheel is ready to transition to the slip engagement state.
Even if the one-way clutch drive wheel side rotation speed decreases to the power source side rotation speed and the one-way clutch is engaged, the engagement shock can be absorbed by the slip of the friction element. Therefore, it is possible to avoid the engagement shock from occurring on the drive wheel, and there is no possibility that the riding comfort performance of the vehicle is impaired.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 shows a wheel drive system (power train) of a hybrid vehicle equipped with the inertial traveling control device of the present invention, together with its control system,
1 is a motor / generator as a first power source, 2 is an engine as a second power source, and 3L and 3R are left and right drive wheels (left and right rear wheels), respectively.

  In the power train of the hybrid vehicle shown in FIG. 1, the automatic transmission 4 is arranged in tandem at the rear of the engine 2 in the longitudinal direction of the vehicle in the same manner as a normal rear wheel drive vehicle, and the engine 2 (crankshaft 2a) is rotated. A motor / generator 1 is provided in combination with a shaft 5 that transmits to the input shaft 4a of the automatic transmission 4.

The motor / generator 1 is an AC synchronous motor, which acts as a motor when driving the wheels 3L and 3R, and acts as a generator (generator) when regeneratively braking the wheels 3L and 3R. Place between 4 machines.
A first clutch 6 is interposed between the motor / generator 1 and the engine 2, more specifically, between the vehicle front end of the shaft 5 of the motor / generator 1 and the engine crankshaft 2a. The motor / generator 1 is detachably connected.
Here, the transmission torque capacity of the first clutch 6 can be changed continuously or stepwise. For example, the transmission torque capacity can be changed by continuously controlling the clutch hydraulic oil flow rate and the clutch hydraulic pressure with a proportional solenoid. It consists of a simple wet multi-plate clutch.

A second clutch 7 is inserted between the motor / generator 1 and the automatic transmission 4, more specifically between the vehicle front end of the shaft 5 and the transmission input shaft 4a, and the motor / generator 1 and the automatic transmission are connected by the second clutch 7. The transmissions 4 are coupled so as to be separable.
Similarly to the first clutch 6, the second clutch 7 can change the transmission torque capacity continuously or stepwise. For example, the proportional hydraulic solenoid can continuously control the clutch hydraulic fluid flow rate and the clutch hydraulic pressure to transmit torque. It consists of a wet multi-plate clutch whose capacity can be changed.

The automatic transmission 4 is the same as that described on pages C-9 to C-22 of the "Skyline New Car (CV35) Manual" published by Nissan Motor Co., Ltd. in January 2003. By selectively engaging or releasing a shift friction element (such as a clutch or a brake), a transmission system path (shift stage) is determined by a combination of engagement and release of these shift friction elements.
Accordingly, the automatic transmission 4 shifts the rotation from the input shaft 4a with a gear ratio corresponding to the selected shift speed, and outputs it to the output shaft 4b.
This output rotation is distributed and transmitted to the left and right rear wheels 3L and 3R by a final reduction gear 8 including a differential gear device, and is used for traveling of the vehicle.

However, the automatic transmission 4 has a gear stage that transmits power via a one-way clutch, and in this embodiment, the forward first speed corresponds to that.
While the drive torque is input from the input shaft 4a on the first power source and the second power source side, the one-way clutch can be engaged to transmit the drive torque to the output shaft 4b on the drive wheel 3 side. At this time, of course, the power source side rotational speed of the one-way clutch and the driving wheel side rotational speed of the one-way clutch are the same.
On the other hand, while the torque is input from the output shaft 4b on the drive wheel 3 side, the one-way clutch is released to be in a coast-free state in which torque is not transmitted to the input shaft 4a on the power source 1, 2 side. When the one-way clutch cuts off torque from the output shaft 4b (drive wheel 3 side) in this coast-free state, the input shaft 4a idles without transmitting power, and the power source of the one-way clutch that is also the rotational speed of the input shaft 4a The side rotational speed is equal to or lower than the driving wheel side rotational speed of the one-way clutch.

In the hybrid vehicle power train shown in FIG. 1 described above, the first clutch 6 is disengaged when the electric travel (EV) mode used at the time of low load and low vehicle speed including when starting from a stopped state is required. Then, the second clutch 7 is engaged, and the automatic transmission 4 is brought into a power transmission state.
When the motor / generator 1 is driven in this state, only the output rotation from the motor / generator 1 reaches the transmission input shaft 4a, and the automatic transmission 4 changes the rotation to the input shaft 4a to the selected shift speed. The speed is changed according to the speed and output from the transmission output shaft 4b.
The rotation from the transmission output shaft 4b then reaches the left and right rear wheels 3L, 3R via the final reduction gear 8 including the differential gear device, and the vehicle can be electrically driven (EV traveling) only by the motor / generator 1.

When hybrid driving (HEV driving) mode used when driving at high speeds, during heavy loads, or when the amount of power that can be taken out by the battery is low, both the first clutch 6 and the second clutch 7 are engaged, The automatic transmission 4 is brought into a power transmission state.
In this state, the output rotation from the engine 2 or both the output rotation from the engine 2 and the output rotation from the motor / generator 1 reach the transmission input shaft 4a, and the automatic transmission 4 is connected to the input shaft 4a. Is rotated according to the selected gear position and output from the transmission output shaft 4b.
Then, the rotation from the transmission output shaft 4b reaches the left and right rear wheels 3L and 3R via the final reduction gear 8, and the vehicle can be hybrid-driven (HEV travel) by both the engine 2 and the motor / generator 1.

  In such HEV traveling, if the engine 2 is operated with the optimum fuel efficiency and the energy becomes surplus, the surplus energy is converted into electric power by operating the motor / generator 1 as a generator by this surplus energy, and this generated power is converted into electric power. By accumulating power to be used for driving the motor of the motor / generator 1, the fuel efficiency of the engine 2 can be improved.

  In FIG. 1, the second clutch 7 for releasably coupling the motor / generator 1 and the drive wheels 3L, 3R is interposed between the motor / generator 1 and the automatic transmission 4, but the automatic transmission 4 and the final deceleration It may be interposed between the machines 8, or a shift friction element for selecting a gear position in the automatic transmission 4 may be used.

FIG. 1 further shows a control system for the engine 2, the motor / generator 1, the first clutch 6, the second clutch 7, and the automatic transmission 4 that constitute the power train of the hybrid vehicle described above.
The control system of FIG. 1 includes an integrated controller 20 that performs integrated control of the operating point of the power train. The operating point of the power train is set to an engine torque target value tTe and a motor / generator torque target value tTm (motor / generator rotation speed target). Value tNm), the first clutch 6 transmission torque capacity target value tTc1 (may be a clutch hydraulic solenoid current Ic1), the second clutch 7 target transmission torque capacity tTc2 (may be a clutch hydraulic solenoid current Ic2), It is defined by the target gear stage Gm of the automatic transmission 4.

  In order to determine the operating point of the power train, the integrated controller 20 receives a signal from the accelerator opening sensor 11 that detects the accelerator opening APO and a signal from the vehicle speed sensor 12 that detects the vehicle speed VSP. .

Here, the motor / generator 1 is driven and controlled via the inverter 22 by the electric power from the battery 21, but as long as the motor / generator 1 acts as a generator as described above, the generated electric power is stored in the battery 21. Shall be kept.
At this time, the battery 21 is controlled to be charged by the battery controller 23 so that the battery 21 is not overcharged.
For this reason, the battery controller 23 detects the state of charge (SOC) of the battery 21 and supplies information related thereto to the integrated controller 20.

The integrated controller 20 selects an operation mode (EV mode, HEV mode) capable of realizing the driving force of the vehicle desired by the driver from the accelerator opening APO, the battery storage state SOC, and the vehicle speed VSP, and the engine. Torque target value tTe, motor / generator torque target value tTm, first clutch transmission torque capacity target value tTc1 (or clutch hydraulic solenoid current Ic1), second clutch transmission torque capacity target value tTc2 (or clutch hydraulic solenoid current Ic2), and The target gear stage Gm of the automatic transmission 4 is calculated.
The engine torque target value tTe is supplied to the engine controller 24, and the motor / generator torque target value tTm is supplied to the motor / generator controller 25.

The engine controller 24 controls the engine 2 so that the engine torque Te becomes the engine torque target value tTe, and simultaneously detects a signal from the engine speed sensor 15 that detects the engine speed Ne (the input side speed of the first clutch 6). Supply to the integrated controller 20.
The motor / generator controller 25 controls the motor / generator 1 via the inverter 22 with the electric power from the battery 21 so that the torque Tm of the motor / generator 1 becomes the motor / generator torque target value tTm.

The integrated controller 20 supplies the first clutch transmission torque capacity target value tTc1 (clutch hydraulic solenoid current Ic1) and the second clutch transmission torque capacity target value tTc2 (clutch hydraulic solenoid current Ic2) to the clutch controller 26, respectively.
On the other hand, the clutch controller 26 supplies the clutch hydraulic solenoid current Ic1 corresponding to the first clutch transmission torque capacity target value tTc1 to the hydraulic control solenoid of the first clutch 6, and the transmission torque capacity Tc1 of the first clutch 6 is the transmission torque capacity. The first clutch 6 is controlled to be engaged so as to coincide with the target value tTc1.
On the other hand, the clutch controller 26 supplies the clutch hydraulic solenoid current Ic2 corresponding to the second clutch transmission torque capacity target value tTc2 to the hydraulic control solenoid of the second clutch 7, and the transmission torque capacity Tc2 of the second clutch 7 is the second clutch. The second clutch 7 is controlled to be engaged so as to coincide with the transmission torque capacity target value tTc2.

  The target gear stage Gm determined by the integrated controller 20 is input to the transmission controller 27, and the transmission controller 27 controls the automatic transmission 4 so that the target gear stage (target gear ratio) tTm is selected.

In this embodiment, the integrated controller 20 controls the rotational speed of the motor / generator 1 through the motor / generator controller 25 so as to meet the object of the present invention. Shall be performed.
Therefore, the second clutch input side rotational speed sensor 13 (second clutch input side rotational speed) that detects the rotational speed (corresponding to Nm) of the motor / generator 1 as the input side rotational speed Nc2i of the second clutch 7 that is a friction element. The second clutch output side rotational speed for detecting the rotational speed of the transmission input shaft 4a (also the power source side rotational speed of the one-way clutch) as the output side rotational speed Nc2o of the second clutch 7. A sensor 14 (corresponding to the second clutch output side rotational speed detection means) and an oil temperature sensor 16 for detecting the hydraulic oil temperature Temp of the second clutch 7 are provided. From these rotation sensors 13 and 14 and the oil temperature sensor 16 Is input to the integrated controller 20 via the clutch controller 26.

  FIG. 2 is a flowchart showing the hydraulic control of the second clutch 7 according to the present embodiment, and the second clutch 7 is engaged, slipped or released based on the processing result of this flowchart.

First, in step S10, whether or not the one-way clutch can be used is read. Specifically, it is detected whether or not the automatic transmission 4 has selected the first forward speed for transmitting power via a one-way clutch. When the one-way clutch cannot be used (No), the process proceeds to step S20, and the hydraulic pressure of the second clutch 7 (CL2) is controlled so that the transmission torque capacity target value tTc2 corresponding to the target driving force of the wheel 3 is obtained.
On the other hand, if the one-way clutch can be used (Yes), the process proceeds to step S30.

In the next step S30, it is determined whether or not the acceleration of the vehicle is equal to or greater than a predetermined negative acceleration threshold value, and the degree of deceleration is confirmed. That is, when the acceleration of the vehicle is not equal to or greater than the acceleration threshold value (No), the hybrid vehicle is decelerating rapidly. Therefore, the process proceeds to step S40, and the hydraulic pressure of the second clutch 7 (CL2) is minimized and the second clutch 7 is release.
On the other hand, when the acceleration of the vehicle is equal to or greater than the acceleration threshold value (Yes), the process proceeds to step S50.

In the next step S50, it is determined whether the driver releases the accelerator pedal and the hybrid vehicle is traveling, that is, whether the vehicle is coasting (coast state). If it is not coasting (coast state) (No), the process proceeds to step S70, and the hydraulic pressure of the second clutch 7 (CL2) is controlled so that the transmission torque capacity target value tTc2 corresponding to the target driving force of the wheel 3 is obtained.
On the other hand, if the vehicle is coasting (coasted state) (Yes), the process proceeds to step S60, and the hydraulic pressure of the second clutch 7 (CL2) is controlled to suitably realize coasting (coasted state).

  In particular, in the present embodiment, the hydraulic pressure of the second clutch 7 is controlled so as to suitably shift from driving traveling (driving state) to coasting traveling (coast state) while the first clutch 6 is engaged and traveling in the HEV mode. At the same time, the integrated controller 20 executes the processing steps shown in the explanatory diagram of FIG. 3 to control the rotational speed of the motor / generator 1 as intended by the present invention, and the inertial running of the hybrid vehicle targeted by the present invention Take control.

  Referring to FIG. 3, first, in step S1, signals from the sensors 11 and 12 are received, and the accelerator opening APO and the vehicle speed VSP are read.

In step S2, whether the hybrid vehicle is driving with the accelerator pedal depressed (APO> 0) or the accelerator pedal is released (APO = 0) from the read accelerator opening APO. Determine whether the vehicle is running.
If it is determined that the vehicle is driving, a wheel drive torque target value tTd is obtained from the vehicle speed VSP and the accelerator opening APO based on a known driving force map, and the engine torque target value tTe is set to realize this tTd. Then, torque control for defining the motor / generator torque target value tTm is performed.

  In step S3, it is determined whether or not the transmission 4 has selected a gear position (first forward speed) for transmitting power via the one-way clutch, and the above-described condition is that the first forward speed is selected. Instead of the torque control, the motor / generator rotation speed target value tNm is switched to the rotation speed control for controlling the motor / generator 1. For this reason, the second clutch 7 is kept engaged.

In the next step S4, the rotational speed target value tNm is calculated. Specifically, the rotational speed Nto of the transmission output shaft 4b is calculated from the vehicle speed VSP and the speed ratio of the final reduction gear 8, and the one-way clutch drive is performed from the output shaft speed Nto and the speed ratio of the first forward speed. The motor / generator speed target is calculated so that the motor / generator speed Nm, which is also the one-way clutch power source side speed, is calculated as a coast free state lower than the one-way clutch drive wheel side speed Nwo by a predetermined value. Command the value tNm to control the rotation speed. As a result, the one-way clutch is released and the transmission 4 is in a neutral state where power is not transmitted.
However, the motor / generator rotational speed target value tNm is set to be equal to or higher than the idle rotational speed Nid so that the motor / generator rotational speed Nm falls below the idle rotational speed Nid of the engine 2 and engine stall does not occur.

In step S4, the hydraulic pressure of the second clutch 7 is reduced to the hydraulic pressure command value Ps_l. The hydraulic pressure command value Ps_l is in any state in consideration of both the case where the driver depresses the accelerator pedal during coasting and the case where the driver reaches the creep driving described later without depressing the accelerator pedal. The value is set to a certain level of second clutch transmission torque capacity so that it can be dealt with immediately.
During coasting, the vehicle speed VSP generally decreases gradually due to traveling resistance or the like, and the one-way clutch driving wheel side rotational speed Nwo also decreases with time. Therefore, the motor / generator rotational speed Nm also gradually decreases while being lower than the rotational speed Nwo by a predetermined value.

In the next step S5, whether the one-way clutch drive wheel side rotational speed Nwo has decreased to Nwo_th, which is a threshold value for lowering the hydraulic pressure of the second clutch 7 and also a threshold value for creep running. Judge whether or not. When it is determined that the one-way clutch driving wheel side rotation speed Nwo is equal to or higher than the threshold value Nwo_th, that is, when the vehicle speed VSP is in a vehicle speed range faster than the creep travel, the one-way clutch driving wheel side rotation speed Nwo is set to the threshold value Nwo_th. Wait until it falls.
On the other hand, when it is determined in step S5 that the one-way clutch drive wheel side rotational speed Nwo has decreased to the threshold value Nwo_th, that is, when the vehicle speed VSP has entered the creep travel vehicle speed range, the process proceeds to step S6.

  In step S6, the hydraulic pressure command value is calculated so that the hydraulic pressure is sufficiently reduced and the second clutch 7 is ready to slip. Specifically, the hydraulic pressure command value of the second clutch 7 is decreased with time to a hydraulic pressure threshold value Ps_th lower than the hydraulic pressure command value Ps_l described above along step S4. The hydraulic pressure threshold value Ps_th is an operating hydraulic pressure at which the second clutch 7 slips when the transmission torque capacity of the second clutch 7 decreases and a torque larger than the transmission torque capacity is input to the second clutch 7. When the operating oil pressure of the second clutch 7 decreases to the oil pressure threshold value Ps_th, the process proceeds to step S7.

In step S7, a motor / generator rotation speed target value tNm is calculated. Specifically, the motor / generator rotation speed target value tNm is ramped up at a predetermined rate of time change, and the second clutch 7 is brought into the slip engagement state. As a result of step S7, the second clutch 7 is in the slip engagement state with a transmission torque capacity that is small enough to be necessary for creep running.
Then, the process steps shown in FIG.

The operation of the inertial running control device according to the above-described embodiment will be described below with reference to FIG.
FIG. 4 shows that the accelerator pedal is released (accelerator opening APO) at the instant t1 when the hybrid vehicle is running HEV with the automatic transmission 4 being put into the first forward speed gear stage where power is transmitted via the one-way clutch. = 0) is performed, and an operation time chart when coasting (inertia) driving is started through coast determination at the subsequent instant t2 is shown.
Prior to the instant t1 at which coasting (inertia) starts, the driving (driving) driving is performed, so that the hydraulic pressure of the second clutch is set to the upper limit value, and a sufficient transmission torque capacity for driving driving is ensured.

  Since the vehicle speed VSP gradually decreases with time from the time t1 when the accelerator pedal is released, the rotational speed Nto of the output shaft 4b gradually decreases after the instant t1, as indicated by the solid line. Further, the one-way clutch drive wheel side rotation speed Nwo that is proportional to the output shaft rotation speed Nto gradually decreases after the instant t1, as indicated by a broken line. Since the coast determination is made at the instant t2, the motor / generator 1 shifts from the torque control to the rotation speed control at the instant t2. As a result, the motor / generator rotation speed Nm is offset to a value lower than the one-way clutch drive wheel side rotation speed Nwo by a predetermined value as indicated by a thick arrow pointing downward, and coast (inertia) in a coast-free state (Nwo> Nm). ) Drive.

In this way, during inertial running from the instant t2, the one-way clutch drive wheel side rotational speed Nwo gradually decreases, so the motor / generator rotational speed Nm also gradually decreases with time. However, since the first clutch 6 is engaged, the engine 2 does not become less than the idling speed Nid. That is, the motor / generator rotation speed Nm is controlled so as to gradually decrease, and is then held at the idle rotation speed Nid when the motor / generator rotation speed Nm decreases to the idle rotation speed Nid.
Further, during inertial running from the instant t2, the hydraulic pressure of the second clutch 7 is reduced to the hydraulic pressure value Ps_l.

  Further, when inertial running starts at the instant t2, the engine torque Te decreases. At the instant t2, the regenerative torque of the motor / generator 1 also decreases so as to be close to zero. Although not shown in the figure, if there is no power generation request to the motor / generator 1, the engine 1 may be fuel cut (fuel supply stopped) after the instant t2.

  When inertial running starts at the instant t2, the upper limit value for limiting the motor / generator torque Tm is decreased. This is to prevent acceleration that the driver does not intend during inertial driving.

  At the instant t3 when the motor / generator rotational speed Nm is the idle rotational speed Nid, when the one-way clutch drive wheel side rotational speed Nwo decreases to the threshold value Nwo_th, the hydraulic pressure of the second clutch 7 is decreased with time from the instantaneous t3. Thus, the hydraulic pressure threshold value Ps_th lower than the above-described hydraulic pressure value Ps_l is set along step S4. At the subsequent instant t4, the hydraulic pressure of the second clutch 7 decreases to Ps_th, and preparation for shifting to the slip engagement state is prepared.

  The one-way clutch drive wheel side rotation speed Nwo also continuously decreases at the instant t3 to t4, while the motor / generator rotation speed Nm is the idle rotation speed Nid, so the rotation speed difference Nwo-Nid at the instant t4 is The rotation speed control becomes smaller than a predetermined value rotation speed difference Nwo−Nm after the instant t2 when the rotation speed control becomes initial.

When the hydraulic pressure of the second clutch 7 reaches the hydraulic pressure threshold value Ps_th at the instant t4, the motor / generator rotational speed Nm is changed from the idle rotational speed Nid to a predetermined time change rate from the instant t4 so that the second clutch 7 is in the slip engagement state. To raise the ramp. On the other hand, since the one-way clutch driving wheel side rotation speed Nwo continues to decrease in coasting, the motor / generator rotation speed Nm becomes larger than the one-way clutch driving wheel side rotation speed Nwo at an instant t5 after the instant t4.
Thus, when the motor / generator rotation speed Nm increases at the instant t5, the one-way clutch is re-engaged and the second clutch 7 that has been completely engaged until then starts shifting to the slip engagement state. The slip of the second clutch 7 is a rotational speed difference Nm−Nti between the motor / generator rotational speed Nm and the rotational speed Nti of the transmission input shaft 4a.

As described above, as a function of this embodiment, even if the one-way clutch is reengaged at the instant t5, the second clutch 7 shifts to the slip engagement state from the instant t5, so that it is driven at the instant t5 as shown in FIG. The wheel side rotation speed Nwo and the transmission output rotation speed Nto do not fluctuate rapidly. That is, a shock due to re-engagement of the one-way clutch is not transmitted to the drive wheel 3 side of the one-way clutch.
At the instant t5, the one-way clutch is re-engaged and the second clutch 7 is (slip) engaged, so that the driving torque of the power sources 1 and 2 is transmitted to the drive wheel 3 side from the instant t5, and the creep running is started. .

  When the re-engagement of the one-way clutch is confirmed at the subsequent instant t6, the motor / generator rotational speed Nm is decreased from the instant t6 toward the idle rotational speed Nid at a predetermined time change rate. This is because it is not necessary to set the engine 2 at a high speed in creep travel in which the first forward speed is selected while the accelerator opening APO is zero. In the rotational speed control after the instant t6, Ne is set to the idle rotational speed Nid. In this way, in this embodiment, creep running by the rotational speed control is started. In other words, the hybrid vehicle shifts from the instant t6 to driving traveling with the driving torques Tm and Te of the power sources 1 and 2.

  According to this embodiment, when the motor / generator rotational speed Nm is maintained at the idle rotational speed Nid, as shown in FIG. 4 and described above, the second clutch 7 is prepared for transition to the slip engagement state after the instant t4. Thus, it can be seen that the transmission output shaft rotational speed Nto proportional to the vehicle speed VSP does not fluctuate between instant t4 and instant t6. That is, according to the rotational speed control of this embodiment, even when power is transmitted through the one-way clutch, it is possible to prevent a shock caused by re-engagement of the one-way clutch when starting creep running.

Next, another embodiment for carrying out inertial running control of a hybrid vehicle targeted by the present invention will be described with reference to FIG.
With respect to the other embodiment, detailed description of the components common to the embodiment described above with reference to FIG. 3 will be omitted, and different components will be described. In the embodiment described above, in step S4 in FIG. The motor / generator rotation speed target value tNm is commanded to control the rotation speed so that the generator rotation speed Nm is lower than the one-way clutch drive wheel side rotation speed Nwo by a predetermined value.
In another embodiment to be described below, the motor / generator rotation speed target value tNm is commanded to control the rotation speed so that the motor / generator rotation speed Nm is set to the idle rotation speed Nid in step S4.

The operation of the inertial traveling control apparatus according to another embodiment described above will be described below with reference to FIG.
FIG. 5 also shows that the accelerator pedal is released (accelerator opening APO) at the instant t1 when the hybrid vehicle is running HEV while the automatic transmission 4 is engaged in the first forward speed gear that transmits power via the one-way clutch. = 0) is performed, and an operation time chart in the case where coasting by coast determination is started at the following instant t2 is shown.

The detailed description of the same operation as the time chart of FIG. 4 described above will be omitted, and different operations will be described. When the vehicle speed VSP gradually decreases with time from the time t1 when the accelerator pedal is released, the rotational speed Nto of the output shaft 4b also becomes a solid line. The one-way clutch drive wheel side rotational speed Nwo, which is proportional to the output shaft rotational speed Nto, gradually decreases after the instant t1, as shown by the broken line. ,
Since the motor / generator 1 shifts from torque control to rotational speed control at the instant t2 when the coast is judged, the motor / generator rotational speed Nm decreases to the idle rotational speed Nid after the instant t2, and this idle rotational speed Nid is maintained. Run coast (inertia) in a coast-free condition (Nwo> Nm).

  Further, when coasting (inertia) starts at the instant t2, the engine torque Te is made substantially zero and the regenerative torque of the motor / generator 1 is made substantially zero. Although not shown strictly, if the engine torque Te becomes negative from the instant t2 because the friction torque of the engine 2 is large, the motor / generator 1 has a positive value to cancel the negative friction torque. Thus, the engine 2 (and the motor / generator speed Nm) can maintain the idling speed Nid.

  The subsequent operation in FIG. 5 after the instant t3 is the same as that in the first embodiment described above with reference to FIG.

By the way, according to the present embodiment, as shown in FIGS. 4 and 5, the transmission 4 can transmit drive torque from the power source 1, 2 side to the drive wheel 3 side, and from the drive wheel 3 side to the power source 1, 2 side. It is instant t2 that the vehicle has entered inertia coasting (coast state) regardless of the driving torque of the power sources 1 and 2 with the forward first speed transmitting power transmitted via the one-way clutch that cuts off torque transmission to the motor. , The motor / generator 2 is rotated so that the motor / generator speed Nm, which is the power source side speed of the one-way clutch, becomes lower than the one-way clutch drive wheel side speed Nwo after the instant t2. The neutral state in which the driving torque of the power sources 1 and 2 is not transmitted while the second clutch 7 is engaged is controlled, and after the instant t3 in this neutral state, the second clutch 7 Because it was configured to enter into preparations for shifting to the slip fastening state by reducing the fastening force,
Even when power transmission is performed via a one-way clutch, when creep running is started, a shock caused by re-engagement of the one-way clutch can be prevented by shifting to a slip engagement state, and riding comfort performance can be improved. .

  Specifically, under the neutral state from the instant t2, when the one-way clutch drive wheel side rotational speed Nwo drops to a predetermined value Nwo_th at the instant t3, the hydraulic pressure of the second clutch 7 becomes the threshold value Ps_th from the instant t3. To the slip engagement state by lowering it toward the neutral state by increasing the motor / generator rotation speed Nm in a ramp at a predetermined rate of change from the instant t4 and slip-engaging the second clutch 7 Shifts to creep running by the driving torque of the power sources 1 and 2.

  In the coast free state according to the present embodiment, the motor / generator rotation speed Nm, which is the one-way clutch power source side rotation speed, is indicated by a thick arrow pointing downward from the one-way clutch driving wheel side rotation speed Nwo after the instant t2 in FIG. The number of revolutions of the motor / generator 1 is controlled so as to decrease by a predetermined value. Thus, when the preparation for shifting to the slip engagement state described above is entered, the one-way clutch engagement shock that is the object of the present invention can be preferably eliminated.

  Alternatively, in the coast free state, the speed of the motor / generator 1 is controlled so that the motor / generator speed Nm, which is the one-way clutch power source side speed, becomes the idling speed Nid of the engine 2 after the instant t2 in FIG. Also good.

  The above description is merely an example of the present invention, and the present invention can be variously modified without departing from the spirit of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram showing a power train of a hybrid vehicle including an inertial traveling control device according to an embodiment of the present invention, together with its control system. 3 is a flowchart relating to a control portion of a second clutch of the integrated controller in FIG. FIG. 2 is an explanatory diagram showing a process of inertial running control executed by an integrated controller in FIG. FIG. 4 is an operation time chart showing an action by inertial running control of the hybrid vehicle in FIGS. FIG. 5 is an operation time chart similar to FIG. 4, showing an action by inertial running control of a hybrid vehicle according to another embodiment of the present invention.

Explanation of symbols

1 Motor / Generator 2 Engine
3L, 3R Left and right drive wheels 4 Automatic transmission (built-in one-way clutch)
5 Motor / generator shaft 6 1st clutch 7 2nd clutch 8 Final reduction gear
11 Accelerator position sensor
12 Vehicle speed sensor
13 Second clutch input side rotation sensor
14 Second clutch output side rotation sensor
15 Engine rotation sensor (1st clutch input side rotation sensor)
16 Second clutch hydraulic oil temperature sensor
20 Integrated controller
21 battery
22 Inverter
23 Battery controller
24 Engine controller
25 Motor / generator controller
26 Clutch controller
27 Transmission controller

Claims (4)

A power source including an engine and a motor / generator, and a friction element that is in a state of fastening, slipping, or releasing according to a fastening force on a power transmission path from the power source to the driving wheel, and a plurality of friction elements In a hybrid vehicle in which a transmission capable of selecting a gear position is inserted,
In a state in which the transmission selects a gear stage that transmits power via a one-way clutch that enables transmission of driving torque from the power source side to the driving wheel side and cuts off transmission of torque from the driving wheel side to the power source side. When it is detected that the vehicle has entered inertia running regardless of the driving torque of the power source, the rotational speed of the power source is controlled so that the power source side rotational speed of the one-way clutch is lower than the driving wheel side rotational speed. A neutral state in which the driving torque of the power source is not transmitted while the friction element is fastened,
An inertial traveling control device for a hybrid vehicle configured to start preparation for shifting to a slip engagement state by reducing the engagement force of the friction element under the neutral state. In the inertial traveling control device for a hybrid vehicle according to claim 1,
Under the neutral state, when the drive wheel side rotation speed of the one-way clutch is reduced to a predetermined value, the fastening force of the friction element is reduced, and preparations for shifting to the slip engagement state are started.
The inertia of the hybrid vehicle, wherein the rotational speed of the power source is increased at a predetermined rate of time change and the friction element is slip-engaged to make a transition from the neutral state to driving traveling by the driving torque of the power source. Travel control device. In the inertial traveling control device for a hybrid vehicle according to claim 1 or 2,
In the coast free state, the inertial travel control device for a hybrid vehicle controls the rotational speed of the power source so that the rotational speed on the power source side of the one-way clutch is lower than the rotational speed on the driving wheel side by a predetermined value. In the inertial traveling control device for a hybrid vehicle according to claim 1 or 2,
In the coast-free state, the inertial travel control device for a hybrid vehicle controls the rotational speed of the power source so that the rotational speed on the power source side of the one-way clutch becomes the idle rotational speed of the engine.

Images