JP2012154452A - Method for predicting torque rise-up and method for starting engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To predict a rise-up change of transmission torque of a hydraulic type frictional engagement device located in an oil bath state, with a high degree of accuracy.SOLUTION: When a K0 clutch is engaged to crank an engine, an integral value Ipk0 of a K0 clutch oil pressure PK0 is calculated which is applied to an oil pressure cylinder within a predetermined integral time TiA before the transmission torque TK0 of the K0 clutch is risen up, and the rise-up change (a response time td and a rise-up gradient φ) of the transmission torque TK0 is predicted based on the K0 clutch oil pressure integral value Ipk0 and an oil temperature To. As a result, the rise-up change of the transmission torque TK0 is predicted with a high degree of accuracy regardless of an operation delay of a piston and presence of an oil film pressure, and driving force variation associated with the rise-up change of the transmission torque TK0 is properly prevented by a motor generator.

Description

  The present invention relates to a torque rise prediction method for a hydraulic friction engagement device, and more particularly to a technique for predicting a rise change in transmission torque of a hydraulic friction engagement device used in an oil bath with high accuracy.

  In a hybrid vehicle in which power transmission between an engine and a rotating machine is connected (disconnected) by a hydraulic friction engagement device, the engine is cranked and started by engaging the hydraulic friction engagement device. In this case, an engine starting method is known that suppresses (compensates) a driving force fluctuation due to a transmission torque of the hydraulic friction engagement device by the rotating machine. The apparatus described in Patent Document 1 is one example, and a motor generator used as a rotating machine and an engine are connected and disconnected by a friction clutch. Further, in Patent Document 2, the relationship between the piston stroke of the hydraulic cylinder of the hydraulic friction engagement device and the transmission torque is obtained in advance, and the change in the transmission torque when the hydraulic friction engagement device is engaged is determined in the piston. Techniques for estimating based on the stroke have been proposed.

JP 2009-227277 A JP 2010-30428 A

  By the way, although not yet known, it is conceivable to dispose a hydraulic friction engagement device between the engine and the rotating machine in an oil bath state in the torque converter from the viewpoint of cost, durability, and the like. In that case, it is necessary to advance the piston while pushing away the hydraulic oil, so that the rise of the transmission torque becomes slow and the rising gradient of the transmission torque becomes gentle due to the oil film generated on the surface of the friction material. Therefore, it is difficult to properly estimate the change in transmission torque.

  FIG. 7 is an example of a time chart schematically showing changes in clutch hydraulic pressure, oil film pressure, and transmission torque of a friction clutch (hydraulic friction engagement device) used in an oil bath, and is a point in the transmission torque column. The chain line is for the dry clutch shown for comparison. In both dry clutch and oil bath type clutch, the transmission torque rises with a delay of the piston operating time from the rise of the clutch oil pressure at time t1, but in the case of oil bath type clutch, it is necessary to push forward the hydraulic oil and advance it. Therefore, the rise is slower than dry clutch. Also, when the friction material is pressed by the piston, oil film pressure is generated, and when the friction material is frictionally engaged by pushing away the oil film, the transmission torque rises, but the oil film is gradually discharged, The rise of transmission torque also becomes gradual. The oil film pressure graph is shown based on actual measurement values obtained by actually measuring the oil film pressure between the piston and the friction material by embedding a hydraulic pressure sensor in the front end face of the piston. The time t2 in FIG. 7 is the time when the piston substantially reaches the forward end that presses the friction material, and the time t3 is the time when the oil film pressure becomes maximum, and then the oil film is gradually discharged from the surface of the friction material. As a result, the transmission torque gradually increases, and reaches the target transmission torque corresponding to the clutch hydraulic pressure at time t4. The time from t1 to t4 varies depending on the clutch operating conditions such as the oil temperature, but is, for example, about 100 milliseconds to several hundred milliseconds.

  The hydraulic control of the clutch hydraulic pressure (first fill time, hydraulic pressure value, etc.) is performed using clutch operating conditions such as hydraulic oil temperature and rotational speed as parameters, along with the rise response time and rise time of the transmission torque. Since the gradient also changes, it has been difficult for the conventional technique to appropriately predict the rising change (response time, gradient, etc.) of the transmission torque regardless of the difference in hydraulic control. That is, the change in the clutch hydraulic pressure corresponds to the piston stroke, but as is apparent from FIG. 7, the transmission torque rises later than the clutch hydraulic pressure, and the response time and rise gradient are not constant. Therefore, it is difficult to predict the rising change in transmission torque.

  Such a problem is not limited to the hydraulic friction engagement device in the torque converter, and similarly occurs when the hydraulic friction engagement device in the oil bath is engaged in a short time. This is a new problem peculiar to the case where the friction engagement device is used in an oil bath state.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to be able to predict the rising change of the transmission torque of the hydraulic friction engagement device arranged in an oil bath with high accuracy. There is to do.

  In order to achieve such an object, the first invention is a method for predicting a rising change in the transmission torque of a hydraulic friction engagement device used in an oil bath, wherein the hydraulic friction engagement device is engaged. Of the actual hydraulic pressure applied to the hydraulic friction engagement device within a predetermined integration time from the start of hydraulic control to the time before the transmission torque of the hydraulic friction engagement device rises. An integral value is calculated, and a rising change in the transmission torque of the hydraulic friction engagement device is predicted based on the integral value.

  According to a second aspect of the present invention, there is provided a hybrid vehicle in which a hydraulic friction engagement device for connecting and disconnecting power transmission between an engine and a rotating machine is disposed in an oil bath in a torque converter. An engine starting method that suppresses fluctuations in driving force due to transmission torque of the hydraulic frictional engagement device when the engine is cranked and started by engaging with the rotating machine. The hydraulic friction engagement device within a predetermined integration time between the start of hydraulic control for engaging the friction engagement device and before the transmission torque of the hydraulic friction engagement device rises A torque rise prediction step of calculating an integral value of the actual hydraulic pressure applied to the hydraulic pressure, and predicting a rise change of the transmission torque of the hydraulic friction engagement device based on the integral value; and (b) the torque And having a driving force change suppression step of controlling the torque of the rotating machine in response to the rise change of the predicted transfer torque in the up prediction process.

  According to the torque rise prediction method of the first aspect of the invention, an integral value of the actual hydraulic pressure applied to the hydraulic friction engagement device is calculated within a predetermined integration time before the transmission torque rises, and based on the integral value. Since the rising change (response time, rising gradient, etc.) of the transmission torque is predicted, the rising change of the transmission torque can be predicted with high accuracy regardless of the operation delay of the piston and the existence of the oil film pressure. That is, the inventors of the present application examined the relationship between the hydraulic integrated value within the integration time and the rise response time of the transmission torque while variously changing the hydraulic control, and found that a high correlation with a correlation coefficient R of 0.95 or higher. It was found that the obtained approximate line can be set. In addition, when the relationship between the rise response time and the rise slope was examined, it was possible to set an approximate line with which a high correlation was obtained, and eventually the rise response time of the transfer torque based on the hydraulic integral value and It was found that the rising slope can be predicted with high accuracy. This is because the integral value of the working oil pressure is the average oil pressure within the integration time, which is related to the subsequent oil pressure change, the remaining piston operation time, the oil film discharge time after the piston operation, and the rise of the transmission torque accompanying the oil film discharge This is thought to affect

  In the engine starting method according to the second aspect of the present invention, when the engine is cranked and started by engaging the hydraulic friction engagement device, fluctuations in the driving force due to the transmission torque of the hydraulic friction engagement device are caused by the rotating machine. In the same manner as in the first aspect of the invention, the rising change in the transmission torque of the hydraulic friction engagement device is predicted, and the torque of the rotating machine is adjusted in response to the predicted change in the rising transmission torque. Control. Therefore, as with the first invention, the rising change of the transmission torque can be predicted with high accuracy regardless of the piston operation delay and the oil film pressure, and the driving force fluctuation accompanying the rising change of the transmission torque is appropriately suppressed by the rotating machine. can do. Also, in the oil bath state, the piston operation (moving speed) slows down and the response time until the torque rises becomes long. Thus, the transmission is performed based on the hydraulic integrated value within the predetermined integration time before the transmission torque rises. It is possible in time to predict the torque change and control the torque of the rotating machine in response to the change.

It is the schematic block diagram which showed the principal part of the control system | strain in addition to the main point figure of the hybrid vehicle to which the method of this invention is applied suitably. It is a block diagram of the hydraulic circuit regarding the K0 clutch with which the hydraulic control apparatus of FIG. 1 is provided. 2 is a flowchart for specifically explaining the operation of K0 clutch engagement means and torque rise prediction means functionally provided in the electronic control device of FIG. 1. 3A and 3B are diagrams for explaining a data map used when predicting a rising change in transmission torque in step S7 of FIG. 3, in which FIG. 3A is a map for determining a rising response time from a hydraulic integral value, and FIG. It is a map which calculates | requires a gradient. 6 is a time chart schematically showing change characteristics of a K0 clutch oil pressure PK0 and a transmission torque TK0 that change with a difference in oil pressure command value when the K0 clutch is engaged. 10 is a time chart for explaining an example in which the rising change of the transmission torque TK0 differs depending on the history of the K0 clutch oil pressure PK0 even when the integral value Ipk0 of the K0 clutch oil pressure is substantially the same. It is a time chart which shows an example of a change of clutch oil pressure, oil film pressure, and transmission torque at the time of engaging a hydraulic friction clutch used in an oil bath state.

  The torque rise prediction method according to the first aspect of the invention is preferably applied to predicting a rise change in the transmission torque of a hydraulic friction engagement device disposed in an oil bath in a torque converter of a vehicle. The present invention can also be applied to the case where the rising change of the transmission torque of the hydraulic friction engagement device disposed in an oil bath state other than the vehicle or the vehicle is predicted. Further, in a hybrid vehicle, the hydraulic friction engagement device is not limited to the case where the fluctuation of the driving force when the engine is cranked and started by engaging the hydraulic friction engagement device is suppressed by the rotating machine. In the same way, it is possible to predict the rising change of the transmission torque in the same way, and in a vehicle other than a hybrid vehicle such as an engine-driven vehicle, a hydraulic friction engagement device disposed in an oil bath state in a torque converter or the like The present invention can also be applied to the case where the rising change of the transmission torque when the two are engaged is predicted. The hydraulic friction engagement device is a single-plate or multi-plate friction clutch or friction brake that is frictionally engaged by a hydraulic cylinder.

  The predetermined integration time for obtaining the integrated value of the working hydraulic pressure is determined in advance according to the hydraulic control pattern or the like, for example, a fixed time (for example, about several tens of milliseconds to several hundreds of milliseconds) from the start of the hydraulic control. It is set appropriately according to the content of the hydraulic control, such as being able to determine a certain time after the control is started. The hydraulic control may be gradually increased after waiting for a constant pressure following the first fill as in the case of a normal dry clutch or the like, but in the oil bath state, it is necessary to push the hydraulic oil away and advance the piston. It is desirable to output a hydraulic pressure command in a feed-forward manner so that the target hydraulic pressure corresponding to the target transmission torque immediately follows the first fill. In such a case, the hydraulic friction engagement device can be appropriately engaged and controlled in a predetermined time by changing the hydraulic value and duration of the first fill in accordance with clutch operating conditions such as oil temperature and rotational speed. Can do.

  The rising change of the transmission torque predicted based on the integral value of the operating hydraulic pressure is a response time or a rising gradient until the transmission torque rises, and may be any one of them depending on the purpose. It is desirable to predict both when suppressing force fluctuations. The response time may be the time until the start of rising of the transmission torque, or may be the time until a predetermined transmission torque (such as the target transmission torque) is reached.

  The actual hydraulic pressure can be measured, for example, by providing a hydraulic sensor on the valve body, but it is desirable to use the hydraulic pressure in the vicinity of the hydraulic cylinder of the hydraulic friction engagement device as much as possible. Correction can also be made in consideration of force and the like. If possible, a hydraulic sensor may be provided in the vicinity of the hydraulic cylinder.

  The torque rise prediction method according to the first aspect of the invention includes, for example, (a) an integration step of calculating an integral value of an actual working oil pressure within a predetermined integration time determined in advance, and (b) a hydraulic type based on the oil pressure integral value. And a rising change calculating step for obtaining at least one of the response time of the transmission torque of the friction engagement device and the rising gradient. The rising change calculating step is configured to calculate a response time and a rising gradient from a correlation such as a predetermined arithmetic expression or map using the hydraulic integral value as a parameter. Since this correlation is affected by the oil temperature of the hydraulic oil, it is desirable to correct it according to the oil temperature or to set the correlation using the oil temperature as a parameter. When the target hydraulic pressure or the target transmission torque changes, the correlation may be set using the target hydraulic pressure or the target transmission torque as a parameter. It is only necessary to predict the rising change of the transmission torque using at least the hydraulic integral value. In addition, since it varies depending on individual differences such as variations in the piston stroke of the hydraulic cylinder, and also varies with time (deterioration) of the hydraulic oil, for example, the rotational speed of an engine or the like that is rotationally driven with the rise of the transmission torque It is also possible to learn and correct the correlation between the hydraulic integrated value and the rise response time by detecting a change.

  In addition, even if the hydraulic integrated value is substantially the same, if the history of the hydraulic value is different, the subsequent change in hydraulic pressure may be different, which may affect the rising change in transmission torque. It is also possible to obtain a rise change in consideration of the hydraulic pressure history. For example, if the oil pressure value is high when the integration time for calculating the integral value has elapsed, the oil pressure will remain high for a while and the rise response time will be shorter than if the oil pressure value is low. Since there is a possibility that the rising gradient may become large, it is conceivable that correction is performed according to the hydraulic pressure value when the integration time has elapsed, or the correlation is set using the hydraulic pressure value as a parameter.

  In the driving force fluctuation suppressing process of the second invention, for example, the torque of the rotating machine is changed with the same change pattern as the predicted rising change of the transmission torque so that the driving force fluctuation due to the rising change of the transmission torque is completely offset. However, it is only necessary to control the torque of the rotating machine so that at least fluctuations in driving force due to rising changes in transmission torque are suppressed. Since this driving force fluctuation is based on the rotational resistance of the engine, the rotating machine torque is controlled with the predetermined rotational resistance of the engine as the upper limit. In addition, when the engine is started by ignition or the like and starts to rotate by itself, it is desirable to similarly control the torque of the rotating machine so that the fluctuation of the driving force due to the fluctuation of the engine torque is suppressed.

  In the second aspect of the invention, power transmission between the engine and the rotating machine is connected / disconnected by the hydraulic friction engagement device. This is because the hydraulic friction engagement device connects the engine and the rotating machine directly and cuts off. The engine and the rotating machine are connected to two rotating elements of a planetary gear device having three rotating elements, and the remaining one rotating element is connected to a case via a hydraulic friction engagement device (brake). The hydraulic friction engagement device can be stopped by being coupled with the hydraulic friction engagement device, and the engine may be cranked and started by controlling the engagement of the hydraulic friction engagement device to stop the rotation. Various modes are possible in which the engine can be cranked by the engagement.

  In the second invention, the torque of the rotating machine is controlled in response to the rising of the transmission torque predicted in the torque rising prediction step. The torque of the rotating machine at this time may be a power running torque that functions as an electric motor. Also, regenerative torque (also referred to as power generation torque) that functions as a generator may be used. The rotating machine is a rotating electric machine, and may be a generator as well as an electric motor, or may be a motor generator that can selectively obtain both functions.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram including a skeleton diagram of a drive system of a hybrid vehicle 10 to which the present invention is preferably applied. This hybrid vehicle 10 includes, for example, an engine 12 that is an internal combustion engine such as a gasoline engine or a diesel engine, and a motor generator MG that functions as an electric motor and a generator. The outputs of the engine 12 and the motor generator MG are transmitted from the torque converter 14 which is a fluid transmission device to the transmission 20 via the turbine shaft 16 and the C1 clutch 18, and further, the output shaft 22 and the differential gear device. 24 to the left and right drive wheels 26. The torque converter 14 includes a lock-up clutch 30 that directly connects the pump impeller and the turbine impeller, and an oil pump 32 is integrally connected to the pump impeller, and the engine 12 and the motor generator MG It is designed to be mechanically rotated. The transmission 20 is a stepped or continuously variable automatic transmission that is shifted by hydraulic pressure, and shift control is performed by an electromagnetic hydraulic control valve, a switching valve, or the like provided in the hydraulic control device 28. The C1 clutch 18 functions as an input clutch of the transmission 20 and is similarly controlled to be disengaged by the hydraulic control device 28.

  Between the engine 12 and the motor generator MG, there is provided a K0 clutch 34 that directly couples them together via a damper 38. The K0 clutch 34 is a single-plate or multi-plate friction clutch that is frictionally engaged by a hydraulic cylinder 36 (see FIG. 2), and is in an oil bath state in the oil chamber 40 of the torque converter 14 from the viewpoint of cost and durability. This corresponds to the hydraulic friction engagement device according to claims 1 and 2. The motor generator MG corresponds to the rotating machine described in claim 2, and is connected to the battery 44 via the inverter 42.

  The hydraulic control device 28 includes the hydraulic circuit 50 of FIG. 2 for controlling the K0 clutch 34, and the hydraulic pressure output from the hydraulic supply source 52 having the oil pump 32 and the like is controlled by an electromagnetic hydraulic control valve 54. By adjusting the pressure, the K0 clutch hydraulic pressure PK0 supplied to the hydraulic cylinder 36 is controlled, and the engagement torque TK0 of the K0 clutch 34 is controlled according to the K0 clutch hydraulic pressure PK0. A K0 hydraulic pressure sensor 56 is connected to the hydraulic cylinder 36 so that the K0 clutch hydraulic pressure PK0 is detected. The detected value of the K0 clutch hydraulic pressure PK0 is supplied to the electronic control unit 60, and the hydraulic control valve 54 is controlled according to the hydraulic pressure command value of the K0 clutch hydraulic pressure PK0 output from the electronic control unit 60. The K0 hydraulic sensor 56 is provided, for example, in a valve body (not shown) in which the hydraulic control valve 54 and the like are provided, but it is desirable that the K0 hydraulic sensor 56 be provided in the vicinity of the hydraulic cylinder 36 if possible.

  The electronic control unit 60 includes a so-called microcomputer having a CPU, a ROM, a RAM, an input / output interface, and the like, and performs signal processing according to a program stored in the ROM in advance using the temporary storage function of the RAM. Do. The electronic control device 60 functionally includes a hybrid control means 62 and a shift control means 64, and the hybrid control means 62 drives only the engine 12, for example, by controlling the operation of the engine 12 and the motor generator MG. The motor generator MG generates electric power during an engine traveling mode that travels using a power source, a motor traveling mode that travels using only the motor generator MG as a driving power source, an engine + motor traveling mode that travels using both of them, vehicle deceleration, etc. A plurality of predetermined driving modes such as a charging driving mode in which the battery 44 is charged under control (also referred to as regenerative control) is switched according to the driving state such as the accelerator operation amount (driver's required driving force) and the vehicle speed. And run. The shift control means 64 controls an electromagnetic hydraulic control valve, a switching valve, and the like provided in the hydraulic control device 28, thereby changing the gear ratio and gear stage of the transmission 20 to an operating state such as an accelerator operation amount and a vehicle speed. Is controlled according to a predetermined shift map as a parameter.

  The electronic control unit 60 is also functionally provided with engine starting means 70. The engine starter 70 engages the K0 clutch 34 when an engine start request is supplied from the hybrid controller 62, for example, when switching from the motor drive mode to the engine drive mode or the engine + motor drive mode. The engine 12 is cranked and the fuel is supplied and ignited to start the engine 12. Specifically, a K0 clutch engagement means 72 that outputs a hydraulic pressure command value of the K0 clutch hydraulic pressure PK0 and engages the K0 clutch 34, a torque rise prediction means 74 that predicts a rise change of the transmission torque TK0 of the K0 clutch 34, The driving force fluctuation suppressing means 76 for suppressing the driving force fluctuation due to the transmission torque TK0 of the K0 clutch 34 and the ignition means 78 for starting the engine 12 by supplying fuel and igniting are functionally provided. In this embodiment, the signal processing for predicting the rising change of the transmission torque TK0 by the torque rising prediction means 74 is the torque rising prediction step, and the signal processing for suppressing the driving force fluctuation by the transmission torque TK0 is driven by the driving force fluctuation suppressing means 76. This is a force fluctuation suppression process.

  FIG. 3 is a flowchart for specifically explaining signal processing (operation) by the K0 clutch engagement means 72 and the torque rise prediction means 74. Step S2 corresponds to the K0 clutch engagement means 72, and steps S3 to S7 are torques. This corresponds to the rise prediction means 74. Of the series of signal processing by the torque rise prediction means 74, steps S3 to S6 function as integration means in the integration process, and step S7 functions as rise change calculation means in the rise change calculation process. In connection with the signal processing by the K0 clutch engagement means 72 and the torque rise prediction means 74, the electronic control device 60 is supplied with a signal representing the K0 clutch oil pressure PK0 from the K0 oil pressure sensor 56, The temperature sensor 46, the MG rotation speed sensor 48, etc. are supplied with a signal representing the oil temperature To of the hydraulic oil, the rotation speed (MG rotation speed) NMG of the motor generator MG, and the like.

  In step S1 of FIG. 3, it is determined whether or not an engine start request is supplied from the hybrid control means 62. If an engine start request is supplied, step S2 and subsequent steps are executed. In step S2, in order to engage the K0 clutch 34, the hydraulic pressure command value of the K0 clutch hydraulic pressure PK0 is output according to a predetermined change pattern. For example, as shown in the upper part of the time chart of FIG. 5, the hydraulic pressure command value is controlled to the target clutch hydraulic pressure corresponding to the target transmission torque immediately after the high pressure first fill. The actual K0 clutch hydraulic pressure PK0 is As shown in the middle part of FIG. Further, the transmission torque TK0 generated according to the K0 clutch oil pressure PK0 is changed later than the K0 clutch oil pressure PK0 as shown in the lower part of FIG.

  Here, since the K0 clutch 34 of this embodiment is disposed in the oil chamber 40 of the torque converter 14 in an oil bath state, the piston of the hydraulic cylinder 36 moves slowly and an oil film is generated on the surface of the friction material. However, the rising change of the transmission torque TK0 is slower than that in the dry type. Further, the duration of the first fill of the hydraulic pressure command value and the hydraulic value (either one or both) are set according to the clutch operating conditions such as the oil temperature To and the MG rotational speed NMG, and the difference in the first fill Thus, the change characteristic of the K0 clutch hydraulic pressure PK0 changes, and the rising response time td and the rising gradient φ of the transmission torque TK0 also change. The solid line, the alternate long and short dash line, and the broken line in each graph of FIG. 5 correspond to each other, and in the case of the broken line with the short first oil pressure value and the short duration, the rising response time td3 becomes longer and the rising gradient φ3 becomes smaller. . In the case of a one-dot chain line with a high first fill hydraulic pressure value and a long duration, the rising response time td1 is shortened and the rising gradient φ1 is increased. The time t1 in FIG. 5 is the output start time of the hydraulic pressure command value, that is, the start time of the engagement control of the K0 clutch 34, the time t3 is the time when the transmission torque TK0 reaches the target transmission torque in the case of the one-dot chain line, and the time t4 is The time when the transmission torque TK0 reaches the target transmission torque in the case of the solid line, and the time t5 is the time when the transmission torque TK0 reaches the target transmission torque in the case of the broken line. FIG. 5 is a diagram schematically showing, for comparison, the change characteristics of the K0 clutch hydraulic pressure PK0 and the transmission torque TK0 that change in accordance with the difference in the first fill, and is not necessarily accurate.

  Returning to FIG. 3, in the next step S3, the integration timer Ti is reset, and in step S4, the actual K0 clutch oil pressure PK0 supplied from the K0 oil pressure sensor 56 is integrated. The integration processing in step S4, for example, sequentially adds the K0 clutch hydraulic pressure PK0 at each time when it is repeatedly executed at a predetermined cycle time. Since the K0 hydraulic pressure sensor 56 that detects the K0 clutch hydraulic pressure PK0 is provided in the valve body that is separated from the hydraulic cylinder 36, the K0 clutch hydraulic pressure PK0 is based on the pressure loss of the hydraulic pressure caused by the oil passage between them and the centrifugal force accompanying the rotation. Can also be corrected. In step S5, the time measured by the integration timer Ti, that is, the elapsed time since the hydraulic control for engaging the K0 clutch 34 in step S2 is started (time t1 in FIG. 5) is set to a predetermined integration time TiA. Determine whether it has been reached. Until the integration time TiA is reached, the integration process in step S4 is repeatedly executed. On the other hand, when the integration time TiA is reached, step S6 and subsequent steps are executed, and the integration value of the K0 clutch hydraulic pressure PK0 calculated in step S4 is calculated. The value is determined as the K0 clutch hydraulic pressure integral value Ipk0. The time t2 in FIG. 5 is the time when the integral time TiA is reached, and the hatched area shown in the column of the K0 clutch oil pressure PK0 corresponds to the K0 clutch oil pressure integrated value Ipk0 in the case of the solid line.

  The integration time TiA is shorter than the response time until the start of rising of the transmission torque TK0, calculates the rising response time td and the gradient φ based on the K0 clutch hydraulic pressure integrated value Ipk0, and rises the transmission torque TK0. It is set so that the torque of motor generator MG can be controlled so that fluctuations in driving force due to the change are suppressed. In other words, it is desirable to calculate the rising response time td and the gradient φ of the transmission torque TK0 based on the K0 clutch hydraulic pressure integral value Ipk0, but it is desirable to have a time as long as possible. Since torque control needs to be performed, a predetermined time shorter than the shortest time of the rise response time td, which differs depending on the hydraulic control, for example, several tens of milliseconds to several hundreds of milliseconds is set. In this embodiment, TiA ≒ 100msec.

  After obtaining the K0 clutch hydraulic pressure integrated value Ipk0 in this way, step S7 is executed next, and the response time td and the rising gradient φ until the transmission torque TK0 of the K0 clutch 34 rises are set to the K0 clutch hydraulic pressure integrated value Ipk0. Predict based on. Specifically, the rise response time td corresponding to the actual K0 clutch hydraulic pressure integral value Ipk0 is calculated using the response time-hydraulic pressure integral value map shown in FIG. Similarly, the rising gradient φ corresponding to the actual rising response time td is calculated using the gradient-response time map shown in FIG. The maps (bold solid lines) shown in FIGS. 4 (a) and 4 (b) above show the K0 clutch hydraulic pressure while variously changing the hydraulic control (the hydraulic value and duration of the first fill) when the K0 clutch 34 is engaged. The integral value Ipk0 is calculated, the response time td until the transmission torque TK0 reaches the target transmission torque and the rising gradient φ are measured, and the correlation between the K0 clutch hydraulic pressure integral value Ipk0 and the response time td, the response time td It is obtained as a correlation with the rising gradient φ. “O” marks shown in FIGS. 4A and 4B are actual measured values, and it was possible to set an approximate line (map) for obtaining a high correlation with these measured values. In particular, with regard to the correlation between the response time and the hydraulic integrated value in FIG. 4A, a high correlation having a correlation coefficient R of 0.95 or more (R≈0.972 in the embodiment) with respect to the measured value is obtained. . The error between the map and the actually measured value in FIG. 4 (a) is ± several tens of milliseconds, which is sufficient for suppressing the driving force fluctuation (shock) due to the rising of the transmission torque TK0 by the torque control of the motor generator MG. It is accuracy.

  Since the response time-hydraulic pressure integral value map of FIG. 4A is affected by the oil temperature To of the hydraulic oil, the oil temperature To is set as a parameter. In addition, since it varies depending on individual differences such as variations in the piston stroke of the hydraulic cylinder 36 and also varies with time (deterioration) of hydraulic oil, for example, the rotation of the engine 12 that is rotationally driven with the rise of the transmission torque TK0. It is also possible to learn and correct the response time-hydraulic integrated value map by detecting a change in rotational speed or the like.

  Returning to FIG. 1, when the K0 clutch 34 is engaged to crank the engine 12, the driving force fluctuation suppressing means 76 cancels the driving force fluctuation caused by the rising change of the transmission torque TK0. Therefore, the power running torque of the motor generator MG is increased in response to the rising change of the transmission torque TK0 determined from the response time td and the gradient φ obtained by the torque rising prediction means 74. The rise start time of the transmission torque TK0 can be obtained by subtracting the required rise time obtained by dividing the target transfer torque by the rise gradient φ from the response time td to reach the target transfer torque. Correspondingly, the power running torque of motor generator MG may be increased with rising gradient φ. In this case, since the driving force fluctuation is based on the rotational resistance of the engine 12, the increase range of the power running torque is set with the predetermined rotational resistance of the engine 12 as an upper limit. Further, when the engine 12 is cranked by the engagement control of the K0 clutch 34 in this way, the engine 12 is started by supplying fuel and igniting by the ignition means 78. And the driving force fluctuates due to this engine torque. For this reason, the driving force fluctuation suppressing means 76 executes the driving force fluctuation suppressing control caused by the engine starting, following the driving force fluctuation suppressing control due to the rise of the transmission torque TK0 of the K0 clutch 34. Specifically, the power running torque of motor generator MG is reduced according to a preset cancellation pattern according to engine torque fluctuation at the time of engine start.

  Thus, in the hybrid vehicle 10 of the present embodiment, when the engine 12 is cranked by engaging the K0 clutch 34, the transmission torque TK0 of the K0 clutch 34 is within the predetermined integration time TiA before rising. An integral value Ipk0 of the K0 clutch hydraulic pressure PK0 applied to the hydraulic cylinder 36 is calculated, and a rising change (response time td and rising gradient φ) of the transmission torque TK0 is predicted based on the K0 clutch hydraulic pressure integrated value Ipk0 and the oil temperature To. Therefore, the rising change of the transmission torque TK0 can be predicted with high accuracy regardless of the operation delay of the piston and the presence of the oil film pressure. Then, in order to increase the power running torque of the motor generator MG in response to the predicted rise change of the transmission torque TK0, it is possible to appropriately suppress the driving force fluctuation accompanying the rise change of the transfer torque TK0 by the motor generator MG. it can. In this case, in the oil bath state, the operation of the piston is slowed down and the response time td until the torque rises becomes long. Thus, the K0 clutch hydraulic pressure integrated value Ipk0 within the predetermined integration time TiA before the transmission torque TK0 rises in this way. It is possible to predict the rising change of the transmission torque TK0 based on the above and control the torque of the motor generator MG in response to the rising change.

  In the above embodiment, the rising change (response time td and rising gradient φ) of the transmission torque TK0 is predicted based on the K0 clutch hydraulic pressure integrated value Ipk0 and the oil temperature To, but the K0 clutch hydraulic pressure integrated value Ipk0 and the oil pressure To Even if the temperature To is substantially the same, if the history of the K0 clutch oil pressure PK0 is different, the subsequent oil pressure change is different, which may affect the rising change of the transmission torque TK0. For example, the solid line and the alternate long and short dash line in FIG. 6 have substantially the same integrated value Ipk0 of the K0 clutch hydraulic pressure PK0 from the time when the engagement control of the K0 clutch 34 is started (time t1) to the time t2 when the integration time TiA has elapsed. When the first fill hydraulic pressure command value is high and the duration time is short as indicated by the alternate long and short dash line, the K0 clutch hydraulic pressure PK0 is higher than the solid line at the beginning of the hydraulic control, but starts to decrease in a short time, and the integration time TiA is The K0 clutch hydraulic pressure PK02 at the time when it has elapsed (time t2) is lower than that in the case of the solid line. Therefore, the subsequent K0 clutch hydraulic pressure PK0 also changes at a lower pressure than in the case of the solid line, and the rising response time td2 becomes longer and the rising gradient φ2 becomes smaller. Therefore, it is desirable to predict the rise change (response time td and rise gradient φ) in consideration of the change (history) of the K0 clutch hydraulic pressure PK0 within the integration time TiA. For example, when the integration time TiA has elapsed (time Correction may be made according to the K0 clutch hydraulic pressures PK0A1 and PK0A2 at t2), or the response time-hydraulic integral value map of FIG. 4 (a) may be set using the K0 clutch hydraulic pressure PK0A at the time t2 as a parameter. The time t3 in FIG. 6 is the time when the transmission torque TK0 reaches the target transmission torque in the case of the solid line, and the time t4 is the time when the transmission torque TK0 reaches the target transmission torque in the case of the alternate long and short dash line. FIG. 6 is a diagram schematically showing, for comparison, the change characteristics of the K0 clutch hydraulic pressure PK0 and the transmission torque TK0 that change with the difference in the first fill as in FIG.

  As mentioned above, although the Example of this invention was described in detail based on drawing, these are one Embodiment to the last, This invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.

  DESCRIPTION OF SYMBOLS 10: Hybrid vehicle 12: Engine 14: Torque converter 34: K0 clutch (hydraulic friction engagement device) 56: K0 hydraulic sensor 60: Electronic control device 70: Engine starting means 72: KO clutch engagement means 74: Torque rise prediction Means (torque rise prediction step) 76: Driving force fluctuation restraining means (driving force fluctuation restraining step) MG: Motor generator (rotating machine) TiA: Integration time Ipk0: K0 clutch hydraulic pressure integral value (integration value) td: Rise response time φ : Rising slope

Claims (2)

A method for predicting a rising change in transmission torque of a hydraulic friction engagement device used in an oil bath,
The hydraulic frictional engagement is performed within a predetermined integration time from the start of hydraulic control for engaging the hydraulic frictional engagement device to before the transmission torque of the hydraulic frictional engagement device rises. An integral value of the actual hydraulic pressure applied to the combined device is calculated, and a rising change in the transmission torque of the hydraulic friction engagement device is predicted based on the integral value. Torque rise prediction method. In a hybrid vehicle in which a hydraulic friction engagement device for connecting and disconnecting power transmission between an engine and a rotating machine is disposed in an oil bath state in a torque converter, by engaging the hydraulic friction engagement device When starting the engine by cranking, the engine starting method suppresses a driving force variation due to a transmission torque of the hydraulic friction engagement device by the rotating machine,
The hydraulic frictional engagement is performed within a predetermined integration time from the start of hydraulic control for engaging the hydraulic frictional engagement device to before the transmission torque of the hydraulic frictional engagement device rises. A torque rise prediction step of calculating an integral value of actual hydraulic pressure applied to the combined device, and predicting a rise change of the transmission torque of the hydraulic friction engagement device based on the integral value;
A driving force fluctuation suppressing step of controlling the torque of the rotating machine in response to the rising change of the transmission torque predicted in the torque rising prediction step;
An engine start method for a hybrid vehicle characterized by comprising:

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