JP4078940B2 - Engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine control device that reduces shift shock by increasing engine torque during downshifting of an automatic transmission.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a technique for reducing shift shock by increasing engine output torque during downshifting of an automatic transmission is known (see, for example, Patent Document 1).
Such torque-up control at the time of downshift is an inertia phase from when the clutch of the current gear stage (for example, third gear) starts to be disengaged until the connection of the clutch of the next gear (for example, second gear) is started. The shift shock is prevented by increasing the engine output torque.
[0003]
[Patent Document 1]
JP-A-9-105458 [0004]
[Problems to be solved by the invention]
By the way, conventionally, the engine output torque is increased by calculating an engine output torque that achieves the engine speed after downshifting (hereinafter referred to as a rotation synchronization torque) and controlling the engine output torque to be the rotation synchronization torque. For example, in the case of an automatic transmission having a manual transmission mode capable of manual shifting, downshifting is performed by the driver's operation. There is a risk of a sudden increase in rotation being calculated.
[0005]
In addition, if an incorrect rotation synchronization torque is calculated regardless of whether the manual transmission mode or the automatic transmission mode is selected, a torque exceeding the expected value is input to the automatic transmission during the shift, and the clutch There is also a problem that abnormal wear or the like occurs.
The present invention has been made in view of such problems, and an object of the present invention is to reliably prevent an excessive increase in engine output torque in an engine control device that controls increase in engine output torque during downshifting. .
[0006]
[Means for Solving the Problems]
Therefore, Therefore, the present invention comprises an automatic transmission manual transmission capable by the driver, the engine control system to increase the control of the engine output torque during the downshift, when there is a downshift operation by the driver, Estimate the engine speed after downshifting , and set a torque increase limit value for each shift stage after downshifting with respect to the required torque increase calculated to achieve the estimated engine speed. I made it.
[0007]
【The invention's effect】
According to the engine control apparatus of the present invention, when a downshift operation is performed by the driver , the torque increase amount for effectively reducing the shift shock accompanying the downshift is calculated, A torque increase amount limit value is set for viewpoints other than reduction, for example, for ensuring safety or performance (maintenance). As a result, the shift shock during downshift due to driver operation is reduced as much as possible, while preventing an excessive increase in engine output torque, exceeding the expected torque is input to the automatic transmission, and sudden rotation increases Can be avoided reliably.
Here, since the torque increase amount limit value is set for each gear position after the downshift, an appropriate limit value can be provided according to the gear position, while preventing an excessive increase in engine output torque, The shift shock at each shift stage can be reduced to the maximum.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system configuration diagram of an engine according to an embodiment of the present invention. In FIG. 1, a throttle valve 4 driven by a throttle motor 3 is provided in an intake passage 2 of the engine 1.
[0009]
An automatic transmission 5 is connected to the output side of the engine 1. The automatic transmission 5 has a manual shift mode in which manual shift can be performed according to a driver's request in addition to the automatic shift mode, and includes a torque converter 6 connected to the output shaft of the engine 1, and the torque converter 6 is provided with a transmission mechanism (gear mechanism) 7 coupled to the output side of 6 and a hydraulic control mechanism 8 for performing coupling / disengaging operations of various transmission elements (such as a clutch) in the transmission mechanism 7.
[0010]
The hydraulic pressure for the hydraulic control mechanism 8 is controlled through various electromagnetic valves, but only the shift solenoids 9 and 10 for automatic shifting and the lockup solenoid 11 for lockup are shown here. The shift solenoids 9 and 10 and the lockup solenoid 11 are connected to an electronic control unit (hereinafter referred to as ECU) 12.
[0011]
The ECU 12 includes a throttle sensor 21 that detects the opening of the throttle valve 4, an accelerator opening sensor 22 that detects the depression amount APS of the accelerator pedal, a water temperature sensor 23 that detects the engine coolant temperature Tw, and an engine speed Ne. Rotational speed sensor 24, automatic transmission 5 (gear mechanism) gear position sensor 25 for detecting the gear position GP, and the driver operates to set the transmission mode (automatic transmission mode, manual transmission mode) of the automatic transmission 5. A signal is input from a mode switch 26, a shift position sensor 27 that detects a shift lever position SP, a vehicle speed sensor 28 that detects a vehicle speed VSP, and the like.
[0012]
Then, in the automatic shift mode, the ECU 12 sets an optimal shift stage by referring to a preset map based on the accelerator operation amount APS and the vehicle speed VSP, so that the set shift stage is set. The shift solenoids 114 and 15 are controlled. On the other hand, in the manual shift mode, the upshift side or downshift side shift stage is set by one step from the current shift stage in accordance with the upshift operation or downshift operation performed by the driver via the shift lever. Then, the shift solenoids 14 and 15 are controlled so as to achieve this shift stage.
[0013]
The ECU 12 executes engine control such as fuel injection control and ignition timing control based on signals from the various sensors, calculates a target engine torque, and obtains the target engine torque so as to obtain the target engine torque. Engine output torque control is performed by driving the motor 5 and controlling the opening of the throttle valve 4.
Here, engine output torque control (calculation of target engine torque) at the time of downshift executed by the ECU 12 will be described.
[0014]
FIG. 2 is a block diagram showing a portion related to the engine output torque control of the ECU 12. As shown in FIG. 2, the ECU 12 includes a rotation synchronization torque calculation unit 201 and a target engine torque calculation unit 202.
When the downshift operation by the driver is detected in the manual shift mode (that is, when a downshift is requested), the rotation synchronization torque calculation unit 201 estimates the engine rotation speed after the downshift, and the estimated engine An engine output torque (rotation synchronization torque) vTQTMSTAC for achieving the rotation speed is calculated. The rotation synchronization torque vTQTMSTAC calculated here is calculated so as to effectively reduce the shift shock accompanying the downshift, and is output to the target engine torque calculation unit 202 (first comparison unit 215 described later).
[0015]
The target engine torque calculation unit 202 calculates a target engine torque (hereinafter referred to as rotation synchronous control target torque) TRQNTU at the time of downshift as follows.
First, the driver request engine torque calculation unit 211 calculates an engine output torque (request engine torque) TTEIF requested by the driver based on the accelerator operation amount (accelerator opening) APS, and adds this request engine torque TTEIF to be described later. Output to the unit 213 and the second comparison unit 217.
[0016]
The torque limiter setting unit 212 sets a torque increase upper limit value dTSFTi # for limiting the torque increase with respect to the requested engine torque TTEIF when a downshift is requested (for 4-speed AT: i = 1 to 4). ) Is set. The torque increase amount upper limit value dTSFTi set here is set, for example, so as to prevent a sudden increase in engine output torque (input torque to the automatic transmission 5) in order to ensure (maintain) safety and performance. This is set for each actual gear position CURGP (shift stage) (see FIG. 4).
[0017]
The adder 213 adds the torque increase amount upper limit value dTSFTi to the required engine torque TTEIF to obtain an upper limit value of engine output torque at the time of downshifting (hereinafter referred to as rotational synchronization limit torque) TRQMDLT (= TTEIF + dTSFTi #). This is calculated and output to the first switching output unit 214.
In the first switching output unit 214, there is a downshift request (downshift determination), a manual shift mode (M mode determination), a fuel cut is not being performed (non-fuel cut determination), and the vehicle speed VSP is a predetermined speed ( For example, the rotation synchronization control limit torque TRQMDLT is set on condition that the speed is 10 km / h) or more (vehicle speed determination). On the other hand, if any of the above conditions is not satisfied, a pseudo value (for example, negative max torque) is set, and finally, the required engine torque TTEIF is the target engine torque (rotation synchronization) during the downshift. Control target torque) (see second comparison unit 217 described later). The torque set here is output to the first comparison unit 215.
[0018]
The fuel cut determination is performed by a conflicting control that increases the engine output torque when the rotation synchronization limit torque TRQMDLT is selected during the fuel cut in which the engine output torque (engine speed) decreases. Therefore, by avoiding this, the stability of the control is ensured, and the vehicle speed is determined because the shift shock due to the downshift is small in the low vehicle speed region. By excluding it, the calculation load is reduced while effectively executing this control.
[0019]
The first comparison unit 215 compares the torque output from the first switching output unit 214 with the rotation synchronization torque TQTMSTAC, sets the smaller one, and outputs it to the second switching output unit 216. As a result, when there is a downshift request that satisfies the above conditions, the rotation synchronous torque TQTMSTAC calculated to reduce the shift shock is selected as an upper limit value for safety and performance assurance. It is limited only when it is smaller than the set rotation synchronization limit torque TRQMDLT.
[0020]
The second switching output unit 216 outputs from the first comparison unit 215 on condition that there is no communication error (communication error determination) with the rotation synchronization torque calculation unit 201 (and the target engine torque calculation unit 202). Set the torque. On the other hand, if there is a communication error or the like, a pseudo value (for example, negative max torque) is set in the same way as the first switching output unit 214, and finally the requested engine torque TTEIF is rotationally synchronized. The control target torque is set (see the second comparison unit 217 described later). The torque set here is output to the second comparison unit 217.
[0021]
The second comparison unit 217 compares the torque output from the second switching output unit 216 with the required engine torque TTEIF and selects the larger one as the rotation synchronous control target torque TRQNTU (thus, normally, The torque output from the second switching output unit 216 is selected).
The ECU 12 controls the opening of the throttle valve 4 by driving the throttle motor 5 so that the target engine torque TRQNTU can be obtained, thereby reliably avoiding excessive torque increase and reducing the engine output torque. Torque-up control is executed to suppress shift shock during downshifting.
[0022]
FIG. 3 is a flowchart showing torque up control during downshifting in the manual shift mode described above. In FIG. 3, in step 1, it is determined whether or not the shift mode of the automatic transmission 5 is the manual shift mode. Such a determination is made based on an input signal from the mode switch 26. If it is the manual shift mode (when the M mode is selected), the process proceeds to Step 2. If it is not the manual shift mode (when the automatic shift mode is selected), the process proceeds to Step 9.
[0023]
In step 2, it is determined whether there is a downshift request. Such a determination is made based on an input signal from the shift position sensor 27. If there is a downshift request, go to step 3.
In step 3, it is determined whether or not the vehicle speed is equal to or higher than a predetermined speed (for example, 10 km / h). If the speed is equal to or higher than the predetermined speed, the process proceeds to Step 4.
[0024]
In step 4, it is determined whether or not the fuel is being cut. If the fuel is not being cut, go to step 5.
In step 5, it is determined whether there is a communication error. For example, when the rotation synchronization torque TQTMSTAC is not input from the rotation synchronization torque calculation unit 201 (the target engine torque calculation unit 202 cannot receive) or when it is input but is an abnormal value, there is a communication error. It is determined. If there is no communication error, go to Step 6.
[0025]
In step 6, a rotation synchronization torque TQTMSTAC for suppressing a shift shock at the time of downshift is calculated.
In step 7, the torque increase amount upper limit value dTSFTi corresponding to the gear position is added to the driver request torque TTEIF to calculate the rotation synchronization limit torque TRQMDLT (= TTEIF + dTSFTi #) for ensuring safety and performance.
[0026]
In Step 8, the rotation synchronization torque TQTMSTAC and the rotation synchronization limit torque TRQMDLT are compared to select a smaller one, and the selected torque and the driver request torque TTEIF are compared to determine the larger one. Set as torque TRQNTU.
On the other hand, if it is not the manual shift mode in Steps 1 to 5, if there is no downshift request, if the vehicle speed is lower than the predetermined speed, if the fuel is being cut, or if there is a communication error, go to Step 9. Then, a negative torque max value is set as the rotation synchronization limit torque. In this case, the driver request engine torque vTTEIF is set as the target engine torque (step 9 → 8).
[0027]
FIG. 4 is a flowchart for setting the torque increase amount upper limit value dTSFTi # (i = 1 to 4) (in the case of 4-speed AT).
In FIG. 4, in step 11, it is determined whether or not there is a downshift request. If there is a downshift request, the process proceeds to step 12. If there is no downshift request, the process ends.
[0028]
In Steps 12 to 14, it is determined whether the current actual gear position CURGP (shift speed) is 1st to 4th. If the actual gear position CURGP is the first speed, the routine proceeds to step 15 where a torque increase upper limit value dTSFT1 # (for example, 35N) for the first speed is set and the processing ends. When the actual gear position CURGP is the second speed, the routine proceeds to step 16 and sets the torque increase amount upper limit value dTSFT2 # (for example, 55N) for the second speed, and ends. When the actual gear position CURGP is the third speed, the routine proceeds to step 17 where the torque increase amount upper limit value dTSFT3 # (for example, 85N) for the third speed is set and the processing ends. When the actual gear position CURGP is the fourth speed, the routine proceeds to step 18, and the torque increase upper limit value dTSFT4 # (for example, 126N) for the fourth speed is set and the processing is ended.
[0029]
FIG. 5 is a time chart of the torque-up control when downshifting from the third speed to the second speed.
As shown in FIG. 5, when there is a downshift request, rotation synchronization limit torque TRQMDLT (= TTEIF + dTSFT2) and rotation synchronization torque TQTMSTAC are calculated. Here, since rotation synchronization torque TQTMSTAC> rotation synchronization limit torque TRQMDLT, rotation synchronization limit torque TRQMDLT is selected to become rotation synchronization control target engine torque TRQNTU. The rotation synchronization control target torque TRQNTU is output during a predetermined shift state (for example, from when the 3rd speed clutch starts to disengage until the 2nd speed clutch starts to be connected) (FIG. 5 (b)). ).
[0030]
As a result, the throttle opening is controlled to increase (torque up) so as to obtain the rotation synchronous control target torque TRQNTU (FIG. 5 (c)), and the engine speed increases (FIG. 5 (d)). .
The embodiment described above has the following effects.
(1) Since the torque increase amount upper limit value (limit value) dTSFTi is set for each shift stage, an appropriate limit value can be set according to the shift stage, thereby preventing an excessive increase in engine output torque. However, the shift shock at each shift stage can be reduced to the maximum.
(2) Since the engine output torque is increased by controlling the opening degree of the throttle valve 4, the engine output torque can be easily changed by the ECU 12.
[0031]
In the above embodiment, only the manual shift mode has been described. However, the present invention is not limited to this and may be applied during downshift in the automatic shift mode. In addition to controlling the opening of the throttle valve 4, the engine output torque may be increased by controlling the ignition timing.
[Brief description of the drawings]
FIG. 1 is a system diagram of an engine according to an embodiment of the present invention.
FIG. 2 is a block diagram showing torque up control (rotation synchronization control) during downshifting.
FIG. 3 is a flowchart showing torque-up control (rotation synchronization control) during downshifting.
FIG. 4 is a flowchart for setting a torque increase amount upper limit value.
FIG. 5 is a time chart showing torque-up control during a downshift from the third speed to the second speed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine, 3 ... Throttle motor, 4 ... Throttle valve, 5 ... Automatic transmission, 12 ... Electronic control unit (ECU), 21 ... Throttle sensor, 22 ... Accelerator opening sensor, 25 ... Gear position sensor, 26 ... Mode Switch 27 ... Shift position sensor 28 ... Vehicle speed sensor

Claims (3)

In an engine control device that includes an automatic transmission that can be manually shifted by a driver and that increases engine output torque during downshifting,
When the driver performs a downshift operation, the engine speed after the downshift is estimated, and the shift stage after the downshift is compared with the required torque increase calculated to achieve the estimated engine speed. engine control apparatus wherein the setting the torque increase amount limiting value for each. It said increased control of the engine output torque control system for an engine according to claim 1, characterized in that by increasing the throttle opening. An engine control device including an automatic transmission capable of manual shifting by a driver ,
Driver request torque calculation means for calculating the driver request torque based on the accelerator opening;
A rotation synchronization torque calculating means for estimating the engine rotation speed after the downshift when the driver performs a downshift operation , and calculating a rotation synchronization torque that achieves the estimated engine rotation speed ;
A torque increase amount limit value setting means for setting a torque increase amount limit value for the driver request torque for each gear position after the downshift when a downshift operation is performed by the driver ;
A target engine torque setting means for comparing the rotation synchronization torque with a rotation synchronization limit torque obtained by adding the torque increase amount limit value to the driver request torque and setting the smaller one as a target engine torque;
Output torque control means for increasing the engine output torque so as to achieve the target engine torque;
An engine control device comprising:

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