JP5287825B2 - Idle control device for hybrid vehicle - Google Patents

Description

  The present invention relates to control during idling of a hybrid vehicle that includes an engine and a motor as power sources and in which a clutch is provided between the power source and drive wheels.

  As a vehicle drive system, a motor (generally a motor / generator) is positioned between the engine and the transmission, and the motor and the engine are connected via a first clutch in a form that can be engaged and released, Patent Document 1 discloses a hybrid vehicle in which a second clutch serving as a starting clutch is interposed between a motor and driving wheels.

  Patent Document 1 discloses learning control of the transmission torque characteristic of the first clutch in such a hybrid vehicle. That is, in the mechanical clutch, for example, the stroke position at which the transmission torque rises changes due to secular change or the like. For example, in a state where the engine does not burn and explode, negative torque is applied to the motor as the first clutch is engaged. Therefore, in Patent Document 1, the actual engagement start point of the first clutch is detected and learned based on the torque change of the motor, and appropriate engagement control is always realized regardless of the secular change or the like. Yes.

JP 2010-30428 A

  The fastening start point detection technique as described above can be basically applied also to a clutch (second clutch in Cited Document 1) interposed between a power source (engine and motor) and drive wheels. However, in an idle operation state where the engine is operating and the rotational speed is controlled by the motor (a state where the drive wheel side is unloaded), various demands such as changes in the target idle rotational speed based on the cooling water temperature and power generation If there is a change in the target engine torque due to demand or the like, the motor torque will change. It is difficult to distinguish between a change in motor torque due to such other factors and a change in motor torque due to clutch engagement, and therefore the accuracy of detection of the clutch engagement start point is reduced. There is a problem.

An idle control device according to the present invention includes an engine and a motor that are connected to each other directly or through various mechanisms as a power source, and a hybrid vehicle in which a clutch is interposed between the power source and a drive wheel. The starting point of slip engagement when the clutch transitions from the disengaged state to the slip engaged state is detected based on the torque change or the rotational speed change of the motor. When there is a request to change the clutch from the disengaged state to the slip-engaged state while the engine is operating under torque control and the motor is controlled in rotation speed , Until the detection is completed, a change in the target torque of the engine and a change in the target rotational speed of the motor based on other requests are prohibited .

  That is, in the idle operation state where the engine is operating and the motor is controlled in rotation speed, the motor rotation speed decreases at the actual start point of slip engagement when the clutch transitions from the released state to the slip engagement state. In addition, since the motor torque rises so as to recover from this, the start point of the slip fastening is detected from these changes. In the present invention, when the slip engagement start point is detected, the actual torque of the engine and the actual rotational speed of the motor are stable. The starting point of slip fastening is detected with high accuracy.

  According to the present invention, it is possible to detect the slip engagement start point of the clutch based on a change in the torque or the number of revolutions of the motor with higher accuracy. For example, it is possible to reliably cope with a secular change of the clutch, for example. it can.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing which shows one Example of the power train of the hybrid vehicle to which this invention is applied. Structure explanatory drawing which shows the modification of the power train of the hybrid vehicle to which this invention is applied. Structure explanatory drawing which shows the further modification of the power train of the hybrid vehicle to which this invention is applied. The block diagram which shows the control system of this power train. The flowchart of one Example of the idle control of this invention. The time chart which shows operation | movement of each part at the time of switching an automatic transmission to D range during engine operation.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  First, a basic configuration of a hybrid vehicle to which the present invention is applied will be described. FIG. 1 shows a power train of a hybrid vehicle having a front engine / rear wheel drive (FR) type configuration as one embodiment of the present invention, wherein 1 is an engine and 2 is a drive wheel (rear wheel). The present invention is not limited to this FR format, and can be applied to other formats such as FF format or RR format.

  In the power train of the hybrid vehicle shown in FIG. 1, an automatic transmission 3 is arranged in tandem at the rear of the engine 1 in the vehicle front-rear direction in the same manner as a normal rear wheel drive vehicle, and the engine 1 (crankshaft 1a) A motor / generator 5 is integrally provided on the shaft 4 that transmits the rotation to the input shaft 3 a of the automatic transmission 3.

  The motor / generator 5 is composed of a synchronous motor using a permanent magnet as a rotor, and acts as a motor (so-called “powering”) and also acts as a generator (so-called “regeneration”). As described above, it is located between the engine 1 and the automatic transmission 3. More specifically, a first clutch 6 is inserted between the motor / generator 5 and the engine 1, more specifically between the shaft 4 and the engine crankshaft 1 a, and the first clutch 6 is connected to the engine 1. The motor / generator 5 is detachably coupled.

  Here, the first clutch 6 has a configuration in which the transmission torque capacity can be continuously changed. For example, the first clutch 6 is normally closed so that the transmission torque capacity can be changed by continuously controlling the clutch hydraulic pressure with a proportional solenoid valve or the like. It consists of a dry type single plate clutch or a wet multi-plate clutch.

  Further, a second clutch 7 is interposed between the motor / generator 5 and the drive wheel 2, more specifically, between the shaft 4 and the transmission input shaft 3a. The second clutch 7 is connected to the motor. / The generator 5 and the automatic transmission 3 are detachably coupled.

  Similarly to the first clutch 6, the second clutch 7 is configured so that the transmission torque capacity can be continuously changed. For example, the transmission torque capacity can be changed by continuously controlling the clutch hydraulic pressure with a proportional solenoid valve. It consists of possible wet multi-plate clutch or dry single-plate clutch.

  The automatic transmission 3 selectively engages or releases a plurality of friction elements (such as clutches and brakes), and thus, by changing the engagement / release of these friction elements, the forward speed, the reverse speed, the reverse speed, etc. It is realized. That is, the automatic transmission 3 shifts the rotation input from the input shaft 3a at a gear ratio corresponding to the selected shift speed, and outputs it to the output shaft 3b. This output rotation is distributed and transmitted to the left and right drive wheels (rear wheels) 2 via the differential gear device 8. The automatic transmission 3 is not limited to the stepped type as described above, and may be a continuously variable transmission. The automatic transmission 3 has a P (parking) range and N (neutral) range which are non-traveling ranges, and a D (drive) range and R which are traveling ranges as ranges selected by the driver via a select lever or the like. (Reverse) range at least.

  In the power train described above, an electric vehicle traveling mode (EV mode) that travels using only the power of the motor / generator 5 as a power source, and a hybrid traveling mode (HEV) that travels while the engine 1 is included in the power source together with the motor / generator 5. Mode). For example, the EV mode is required at low loads and low vehicle speeds, including when starting from a stopped state. In this EV mode, the power from the engine 1 is unnecessary, so that the first clutch is stopped. 6 is released and the second clutch 7 is engaged, and the automatic transmission 3 is set in the power transmission state. In this state, the vehicle is driven only by the motor / generator 5.

  Further, for example, the HEV mode is required during high-speed traveling or heavy load traveling. In this HEV mode, the first clutch 6 and the second clutch 7 are both engaged, and the automatic transmission 3 is brought into a power transmission state. In this state, both the output rotation from the engine 1 and the output rotation from the motor / generator 5 are input to the transmission input shaft 3a, and hybrid traveling by both is performed.

  The motor / generator 5 can recover and recover braking energy when the vehicle is decelerated, and can recover surplus energy of the engine 1 as electric power in the HEV mode.

  When transitioning from the EV mode to the HEV mode, the first clutch 6 is engaged and the engine is started using the torque of the motor / generator 5. At this time, the mode can be smoothly switched by variably controlling the transmission torque capacity of the first clutch 6 and performing the slip engagement.

  Further, the second clutch 7 functions as a so-called start clutch, and by variably controlling the transmission torque capacity and starting the slip engagement when starting the vehicle, it absorbs torque fluctuations smoothly even in a power train that does not include a torque converter. The start is possible.

  In FIG. 1, the second clutch 7 located between the motor / generator 5 and the drive wheels 2 is interposed between the motor / generator 5 and the automatic transmission 3, but the embodiment shown in FIG. As described above, the second clutch 7 may be interposed between the automatic transmission 3 and the differential gear device 8.

  In the embodiment shown in FIGS. 1 and 2, a dedicated second clutch 7 is provided at the front or rear of the automatic transmission 3, but instead the second clutch 7 is shown in FIG. As shown, an existing forward shift speed selection friction element or reverse shift speed selection friction element in the automatic transmission 3 may be used. In this case, the second clutch 7 is not necessarily one friction element, and an appropriate friction element corresponding to the gear position can be the second clutch 7.

  FIG. 4 shows a control system in the power train of the hybrid vehicle configured as shown in FIGS.

  The control system includes an integrated controller 20 that integrally controls the operating point of the power train. The operating points of this power train are the target engine torque tTe, the target motor / generator torque tTm (or the target motor / generator rotation speed tNm), the target transmission torque capacity tTc1 of the first clutch 6, and the target of the second clutch 7. And transmission torque capacity tTc2.

  Further, this control system includes at least an engine rotation sensor 11 that detects an engine rotation speed Ne, a motor / generator rotation sensor 12 that detects a motor / generator rotation speed Nm, and an input rotation that detects a transmission input rotation speed Ni. A sensor 13, an output rotation sensor 14 for detecting a transmission output speed No, an accelerator opening sensor 15 for detecting an accelerator pedal depression amount (accelerator opening APO) indicating a required load state of the engine 1, and a motor / generator And a storage state sensor 16 that detects the storage state SOC of the battery 9 that stores the power for 5, and these detection signals are input to the integrated controller 20 to determine the operating point. Has been.

  The engine rotation sensor 11, the motor / generator rotation sensor 12, the input rotation sensor 13, and the output rotation sensor 14 are arranged, for example, as shown in FIGS.

  The integrated controller 20 determines the vehicle driving force requested by the driver from the accelerator opening APO, the battery storage state SOC, and the transmission output speed No (vehicle speed VSP) in the input information. And a target engine torque tTe, target motor / generator torque tTm (or target motor / generator rotation speed tNm), target first clutch transmission torque capacity tTc1, and A target second clutch transmission torque capacity tTc2 is calculated.

  The target engine torque tTe is supplied to the engine controller 21, and the engine controller 21 controls the engine 1 so that the actual engine torque Te becomes the target engine torque tTe. For example, the engine 1 is a gasoline engine, and the engine torque Te is controlled via the throttle valve.

  On the other hand, the target motor / generator torque tTm (or the target motor / generator rotation speed tNm) is supplied to the motor / generator controller 22, and the motor / generator controller 22 receives the torque Tm (or rotation speed Nm) of the motor / generator 5. The motor / generator 5 is controlled via the inverter 10 so that becomes the target motor / generator torque tTm (or the target motor / generator rotational speed tNm).

  Further, the integrated controller 20 applies solenoid currents respectively corresponding to the target first clutch transmission torque capacity tTc1 and the target second clutch transmission torque capacity tTc2 to the engagement control solenoid valves (not shown) of the first clutch 6 and the second clutch 7. ) So that the transmission torque capacity Tc1 of the first clutch 6 matches the target transmission torque capacity tTc1, and the transmission torque capacity Tc2 of the second clutch 7 matches the target second clutch transmission torque capacity tTc2. In addition, the engaged state of the first clutch 6 and the second clutch 7 is individually controlled.

  The integrated controller 20 is also connected to an AT controller 31 that controls the automatic transmission 3. The AT controller 31 determines the optimum gear position from the range position selected by the above-mentioned select lever or the like, the vehicle speed VSP (transmission output rotational speed No), and the accelerator opening APO, and the automatic transmission 3 Shift control is performed by changing the friction elements. Information indicating various states of the automatic transmission 3 is input to the integrated controller 20. As shown in FIG. 3, when the second clutch 7 is substantially constituted by the friction element of the automatic transmission 3, the second clutch 7 is actually controlled via the AT controller 31.

  The flowchart of FIG. 6 shows the control during idling (here, the state in which the driving wheel side is unloaded is referred to as idling and is normally in the vehicle stop state), particularly the second clutch 7. 5 shows the flow of processing of idle control in consideration of the learning control of the characteristics of. This process may be repeatedly executed, for example, during driving, or may be repeatedly executed while such a condition is satisfied on condition that the vehicle is stopped or in an idle state. .

  In step 1, it is determined whether or not the HEV mode in which the engine 1 and the motor / generator 5 are coupled by the first clutch 6. In the EV mode in which the first clutch 6 is disengaged and the engine 1 is stopped, the fluctuation of the engine torque does not affect the learning control of the second clutch 7, and thus this routine ends. The vehicle stop state is basically an EV mode in which the first clutch 6 is disengaged and the engine 1 is stopped, but the power request, the storage state SOC of the battery 9, the engine 1 immediately after the cold start is started. Depending on the warm-up state of the vehicle, the HEV mode with the operation of the engine 1 can be performed even when the vehicle is stopped.

  In step 2, it is determined whether or not the motor / generator 5 is under rotation speed control. During idle operation in which the engine 1 is operating, basically, idle speed control is performed by controlling the rotational speed of the motor / generator 5 (here, the engine rotational speed Ne and the motor / generator rotational speed Nm are equal to each other). Although it is realized, when the state of charge SOC of the battery 9 is extremely small, the motor / generator 5 is torque controlled, and the target idle speed is controlled by the idle speed control mechanism of the engine 1 itself (in other words, the engine controller 21). Like to maintain. Since it is difficult to detect the start of slip engagement of the second clutch 7 during such idle speed control on the engine 1 side, this routine is terminated. In the state where the idle speed control is performed by the speed control of the motor / generator 5, the engine 1 performs torque control, and the actual engine torque Te becomes the target engine torque tTe via the engine controller 21. To be controlled.

  Next, in step 3, it is determined whether or not the automatic transmission 3 has been switched from the P range or N range, which is a non-traveling range, to the D range or R range, which is a traveling range. If switching to the D range or the R range is detected, the process proceeds from step 3 to step 4.

  When the automatic transmission 3 is thus switched to the D range, the automatic transmission 3 is controlled to be shifted to a predetermined gear position, for example, the first speed. The automatic transmission 3 does not include a torque converter, but at the same time, the second clutch 7 is disengaged so as to simulate a weak driving force, that is, a creep force generated when the torque converter is included. Transition from the state to the slip engagement state.

  Here, the second clutch 7 composed of a wet multi-plate clutch or the like has a certain amount of play (so-called backlash) from the start of the stroke to the start point of the slip fastening, and the magnitude of this play is individual difference or secular change. The number of rotations of the motor / generator 5 slightly decreases because the driving wheel side is fixed when the slip engagement is started by increasing the stroke of the second clutch 7. And the torque of the motor / generator 5 increases to compensate for this. Accordingly, it is detected that slip engagement has started from a decrease in the rotational speed or torque increase of the motor / generator 5, and learning control of the slip engagement start point is performed. The detection of the slip fastening start point will be further described later with reference to the time chart of FIG.

  When switching to the D range or R range is detected in step 3, in step 4, the change of the target engine torque tTe of the engine 1 is prohibited and the previous value is repeatedly held. Further, in step 5, the change of the target rotational speed tNm of the motor / generator 5 is prohibited and the previous value is repeatedly held. In other words, even if there is an unnecessary depression of the accelerator pedal (so-called idling), increase / decrease in power generation demand, or change in engine warm-up condition, etc., change of the target value based on these demands is prohibited and The target engine torque tTe of the engine 1 and the target rotational speed tNm of the motor / generator 5 during the rotational speed control are kept substantially constant. Accordingly, the actual torque Te of the engine 1 and the rotational speed Nm of the motor / generator 5 are also substantially constant.

  As described above, the transition to the slip engagement of the second clutch 7 and the learning control thereof are executed under the condition that the torque Te of the engine 1 and the rotation speed Nm of the motor / generator 5 are kept substantially constant.

  In step 6, it is determined whether or not this learning control has been completed, in other words, whether or not the play of the second clutch 7 has been eliminated and slip engagement has been reached. Until this determination becomes YES, the target engine torque tTe and the target rotational speed tNm are kept constant in steps 4 and 5. If YES in step 6, the process proceeds to step 7 and step 8, and the previous value holding of the target engine torque tTe and the target rotational speed tNm is released. In other words, changes based on other requests are allowed.

  FIG. 6 shows an example of a time chart showing the operation of each part when the automatic transmission 3 is switched to the D range during idle operation with engine operation. In this example, the vehicle is stopped during the period shown, and the accelerator opening APO is kept at 0, that is, at the fully closed position. As described above, the rotational speed of the power source composed of the engine 1 and the motor / generator 5 is controlled by the rotational speed control of the motor / generator 5 (in this example, the transmission input rotational speed Ni is assumed on the assumption of the configuration of FIG. 3). Is controlled to the target idle speed.

  When the driver switches from the N range (or P range) to the D range (or R range) as shown as a “select signal” in such an idle operation state, “CL2 command hydraulic pressure” and “CL2 actual hydraulic pressure” As shown, the engagement operation of the second clutch 7 is started via the integrated controller 20 and the AT controller 31. At the same time, as described above, the change of the target engine torque tTe and the target rotational speed tNm of the motor / generator 5 is prohibited, and these are kept constant.

  As an engaging operation of the second clutch 7, in this embodiment, the second clutch 7 is supplied to the second clutch 7 in order to promptly transit to the slip engagement and at the same time avoid a sudden transition to the complete engagement state. The hydraulic pressure command value (CL2 command hydraulic pressure) is controlled in three stages as shown in the figure. That is, after giving a large command value in the initial stage, the command value is gradually reduced in two steps, and then the command value is gradually increased. In the N range, all of the hydraulic pressure of the second clutch 7 is drained, and there is a relatively large play. However, by giving a large command value in the initial stage as described above, the stroke (piston stroke) of the second clutch 7 is reduced. The stroke increases rapidly, and the increasing speed of the stroke becomes gentle as the command value is lowered. The actual oil pressure (CL2 actual oil pressure) gradually increases with a delay as shown in the figure.

  As the stroke of the second clutch 7 increases, the second clutch 7 eventually reaches slip engagement and torque transmission starts. At this time, since the drive wheel 2 side is fixed, the transmission input rotational speed Ni, that is, the rotational speed Nm of the motor / generator 5 is decreased, and the torque Tm of the motor / generator 5 is increased so as to recover this. Therefore, the slip fastening start point (indicated by reference numeral S) is detected by the increase in the torque Tm (or the decrease in the rotational speed Nm). In this way, when it is detected that slip engagement has actually started, the hydraulic pressure command value of the second clutch 7 is further lowered to a value corresponding to the target second clutch transmission torque capacity tTc2 when the vehicle is stopped in the D range. Maintained. Thereby, the second clutch 7 is maintained in the slip engagement state, and a pseudo creep force is applied to the drive wheels 2.

  When the start point of slip engagement is detected, the prohibition of changing the target engine torque tTe and the target rotational speed tNm of the motor / generator 5 is released. In the illustrated example, the target idle speed in the D range is set lower than the target idle speed in the N range. Therefore, the transmission input speed Ni is set to the target idle speed in the D range by the speed control by the motor / generator 5. It decreases to the rotation speed.

  On the other hand, the slip fastening start point S detected as described above is learned in the form of various parameters. For example, the stepwise profile of the hydraulic pressure command value (CL2 command hydraulic pressure) shown in FIG. 6 is learned as the time t from the start of selection to the slip fastening start point S and converges to a predetermined target time. Is corrected for learning. Or you may make it learn simply as a clutch stroke (movement amount or absolute position) from which slip fastening starts.

  As described above, in the above embodiment, the target engine torque tTe and the target rotational speed of the motor / generator 5 are determined regardless of whether or not there is another request from the switching to the D range to the detection / learning of the start point of the slip engagement. Since tNm is held constant, erroneous detection due to these disturbances can be reliably eliminated, and the slip fastening start point can be detected and learned with higher accuracy. In addition, since the change to the target engine torque tTe and the target rotational speed tNm of the motor / generator 5 is prohibited by the switching to the D range as a trigger, the change prohibition period becomes the minimum necessary, and other functions can be used. Adverse effects are minimized.

  As mentioned above, although one Example of this invention was described, this invention is not restricted to the said Example, A various change is possible. For example, in the above embodiment, the automatic transmission 3 is intended for transition to slip engagement when the automatic transmission 3 is artificially switched from the non-travel range to the travel range. The same processing can be performed when it is done.

  In the above embodiment, the target engine torque tTe and the target rotational speed tNm of the motor / generator 5 are fixed to a constant value. However, these are within a predetermined allowable range that does not adversely affect the detection of the start of slip engagement. You may make it accept | permit a slight change of. For example, in steps 4 and 5 of FIG. 5, the amount of change per unit time is limited to a minute amount, or an upper limit value and a lower limit value are set from the initial value, and changes exceeding that range are prohibited. do it.

DESCRIPTION OF SYMBOLS 1 ... Engine 3 ... Automatic transmission 5 ... Motor / generator 6 ... 1st clutch 7 ... 2nd clutch 9 ... Battery 10 ... Inverter 20 ... Integrated controller 21 ... Engine 31 ... AT controller

Claims (2)

The engine includes a motor and a motor connected to each other as a power source, and a clutch is interposed between the power source and the drive wheel, and slip engagement when the clutch transitions from a released state to a slip engaged state. In the hybrid vehicle that detects the starting point of the motor based on the torque change or the rotational speed change of the motor,
When the engine is operating under torque control and the motor is in idle operation where the rotation speed is controlled , the start point is detected when there is a request to change the clutch from the disengaged state to the slip engaged state. A hybrid vehicle idle control device that prohibits a change in target torque of the engine and a change in target rotational speed of the motor based on other requirements until completion . An automatic transmission having a driving range selected by the driver and a non-driving range is interposed between the power source and the driving wheel, and the clutch is released from the non-driving range to the driving range. The hybrid vehicle idle control device according to claim 1 , wherein the idle control device is regarded as a request for transition from a state to a slip engagement state .

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