JPH06146940A - Control device for engine with automatic transmission - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the idle speed control valve malfunctions toward the open side, it is fail-safe so that the engine does not blow up more than necessary. A control device for an engine with an automatic transmission having a main throttle valve 14 and a sub-throttle valve 15 in an intake passage 13 and an idle speed control valve 22 in a passage 21 bypassing the main throttle valve 14 Throttle valve 15 to main throttle valve 14
Is provided downstream of the main throttle valve 14, and the downstream end of the bypass passage 21 provided with the idle speed control valve 22 is communicated with the intake passage 13 at the upstream position of the sub-throttle valve 15. A control means is provided for controlling the opening of the idle speed control valve 22 to a predetermined opening when the manual downshift is performed in the closed state, and for closing the sub-throttle valve 15 to the predetermined opening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an engine with an automatic transmission.

[0002]

2. Description of the Related Art When shifting is performed by an automatic transmission, a specific shift speed is achieved by selectively engaging and disengaging a plurality of friction engagement devices. Further, in this case, a slight overlap is provided at the timing of engagement and disengagement to prevent the engine from rising.

By the way, when it is desired to apply the engine brake for deceleration during traveling, the accelerator is released (fully closed) and the shift lever is operated to the downshift position (for example, 2 range or 1 range while traveling in the D range). To shift to a lower gear.

In a downshift in such a power-off state (for example, a state in which power is transmitted from the wheel side to the engine side such as when the accelerator is fully closed), so-called coast torque due to running inertial force of the vehicle is generated. It is transmitted in reverse from the wheels to the output shaft of the automatic transmission and then to the engine. In the case of manual downshift for the purpose of securing the engine brake, there is no idling of the one-way clutch, so the amount of work that raises the engine speed until the rotation speed matches the vehicle speed and the gear ratio is generated due to the coast torque. As a result, the coast torque is consumed and the vehicle speed instantaneously decreases.

Such a reduction in vehicle speed is greatest at the moment of downshifting from the second gear to the first gear, for example, and sudden engine braking works in a short time to cause a large acceleration change, which causes a passenger to have a large acceleration change. It will be uncomfortable.

In order to eliminate this point, the time (shift time) for engagement and disengagement of the friction engagement device is extended, and these operations are performed more gradually so that the vehicle speed is gradually reduced. It is possible to do it.

However, the gear shifting time is limited by the life and capacity of the friction material, and it is unavoidable to take a substantially constant time. Therefore, after all, the shift shock (shift shock = work load / shift time) is determined by the absolute value of the work amount, making it difficult to take effective measures.

Therefore, conventionally, the downshift line at the time of manual downshift is set to be considerably low so as to reduce the work amount at the time of shifting.

However, in this case, there is a problem in that the downshift cannot be performed unless the vehicle speed is once lowered below the downshift line by depressing the brake without downshifting at a high vehicle speed.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 63-284039, during the power-off manual downshift operation, the idle rotation speed control valve is opened and controlled to raise the engine rotation speed on the engine side to reduce the coast torque. It is considered to reduce consumption.

[0011]

However, in this control, if the idle speed control valve malfunctions toward the open side, the engine may blow up more than necessary, which may give the driver a feeling of strangeness. Considering it, it was difficult to adopt the above-mentioned technology, and it was the current situation that it has not been put to practical use.

The present invention has been made in view of such a conventional problem, and prevents the engine from being blown up more than necessary even if the idle speed control valve malfunctions toward the opening side. Another object of the present invention is to provide a control device for an engine with an automatic transmission.

[0013]

SUMMARY OF THE INVENTION As shown in FIG. 1, the present invention provides a main throttle valve which is arranged in an intake passage of an engine and works in conjunction with an accelerator, and a main throttle valve connected in series with the main throttle valve in the intake passage. And a sub-throttle valve driven by an actuator and an idle rotation speed control valve provided in a passage bypassing the main throttle valve, and the idle rotation when a manual downshift operation is performed in a power-off state. In a control device for an engine with an automatic transmission, which controls a speed control valve to open to a predetermined opening to increase an engine output, the sub-throttle valve is provided downstream of a main throttle valve, and the idle speed control valve is provided. The downstream end of the bypass passage downstream of the main throttle valve Is communicated with the intake passage at an upstream position, and when the manual downshift is performed in the power-off state, the idle rotation speed control valve is controlled to open to a predetermined opening and the sub-throttle valve is opened to a predetermined opening. By providing the control means for controlling the closing,
This is a solution to the above problem.

[0014]

In the apparatus of the present invention, when the manual downshift in the power-off state is detected, the idle speed control valve is controlled to open so as to have the predetermined opening and the sub-throttle valve has the predetermined opening. Is controlled to close. Therefore, even if the idle speed control valve is opened too much, the sub-throttle valve located downstream of the idle speed control valve is closed to a predetermined opening, which prevents the engine from rising more than necessary.

In this case, the sub-throttle valve may be first closed to a predetermined opening degree, and after confirming that, the idle rotation speed control valve may be controlled to open, or conversely, the idle rotation speed control valve may be opened first. The sub-throttle valve may be closed after the opening control is performed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows an intake system of an engine with an automatic transmission and a control system therefor according to the embodiment.

The air sucked from the air cleaner 10 is
Turbocharger 11, intercooler 12, main throttle valve 14 arranged in series on intake passage 13
Then, it is sent to the intake manifold through the sub throttle valve 15 and the surge tank 16 in this order. This air is mixed with fuel injected from the injector near the intake port and is sent to the combustion chamber of the engine body via the intake valve.

The main throttle valve 14 rotates in conjunction with an accelerator pedal 19 provided in the driver's seat. The sub-throttle valve 15 is for controlling the engine torque when controlling an automatic transmission or the like, and is driven by an actuator (stepping motor) 20. In this case, the sub throttle valve 15 is arranged downstream of the main throttle valve 14.

In addition, this intake system includes an air cleaner 10
Bypass passage 21 for guiding the air passing through the main throttle valve 14 directly to the surge tank 16
Is provided. An idle rotation speed control valve (ISC valve) 22 driven by an actuator (stepping motor) is provided at the downstream end of the bypass passage 21, and an outlet side passage of the idle rotation speed control valve 22 is a main throttle valve. It communicates with the intake passage 13 at a position downstream of the valve 14 and upstream of the sub-throttle valve 15.

The idle rotation speed control valve 22 is driven by a signal from the engine computer 30 to control the idle rotation speed. The sub-throttle valve 15 is driven by a signal from the engine computer 30 to control the engine speed.
The engine computer 30 is the automatic transmission computer 4
Signals are exchanged with 0.

The automatic transmission computer 40 has at least a throttle sensor 51 for detecting the opening of the main throttle valve 14, a vehicle speed sensor 52, a shift position sensor 53 for detecting the shift lever position of the automatic transmission, and an engine speed ( Ne) A signal is input from the sensor 54.

The automatic transmission computer 40 executes the shift control using the input signals from the sensors 51 to 54 as parameters, and outputs the engine control data to the engine computer 30 as needed during the shift. Then, the engine computer 30 receives the data and controls the sub-throttle valve 15 and the idle speed control valve 22.

Next, the contents of the control processing operation by the automatic transmission computer 40 will be described with reference to the flow charts of FIGS.

The automatic transmission computer 40 executes a main routine for gear shift control in a predetermined cycle. As a subroutine in the main routine, a shift determination routine of FIG. 3 and a shift processing routine of FIG. 4 are defined.

When the shift judgment routine of FIG. 3 starts, first, in step 202, the shift lever position is read. Next, in step 204, it is determined whether or not the shift lever position has been changed. If the shift lever position has been changed, the shift lever change flag is set to "1" in step 206, and then the process proceeds to step 208. . If the shift lever position has not been changed, the process directly proceeds to step 208.

In step 208, the throttle opening (Th
) Is read, and in the next step 210, the vehicle speed data (V) is read, and in the next step 212, the current throttle opening and the vehicle speed are corresponded from the shift schedule map (the map that defines the relationship between the throttle opening and the vehicle speed). Select the desired target gear (Gt).

Then, in the next steps 214 and 216, the selected target gear stage (Gt) and the current gear stage (Gno) are selected.
w)) to determine whether to downshift or upshift. If it is determined that the downshift should be performed, the process proceeds to step 218, and the DOWN shift flag is set to "1". If it is determined that the upshift should be performed, the process proceeds to step 220 and the UP shift flag is set to "1".
Set to.

If it is determined that neither downshifting nor upshifting should be performed, that is, if the determinations at steps 214 and 216 are both NO, the process proceeds to step 222 even if the shift lever position is changed. Reset the lever position change flag to "0". When the processes of steps 218, 220, 222 are completed, the process returns to the main routine and shifts to the shift process shown in FIG.

When the shift processing routine of FIG. 4 is entered, it is first determined in step 402 whether or not the UP shift flag is set. If YES, the process proceeds to step 408 to control the operation of the shift solenoid valve according to the upshift schedule. In step 410, it is monitored whether or not the upshift is finished. When the upshift is finished, the UP shift flag is reset to "0" in step 412, and the shift lever position change flag is set to "0" in step 414. After resetting, in step 416, the data Gnow of the current gear stage is rewritten to the data Gt (target gear stage) of the target gear stage.

On the other hand, if the UP shift flag is not set, the routine proceeds from step 402 to step 404, where it is determined whether or not the DOWN shift flag is set. When the DOWN shift flag is set, the routine proceeds to step 418, where it is determined whether or not the shift lever position change flag is set.

If the shift lever position change flag is set, the routine proceeds to step 420, where the manual downshift (MD) flag is set to "1", and then proceeds to step 422, where the "torque at manual downshift" is set. The control routine is executed. The contents of this control will be described later.

After executing the torque control process for the manual downshift in step 422, the process proceeds to step 424. When the shift lever position change flag is not set, the above steps 420 and 422 are skipped and the process directly proceeds to step 424. If there is no change in the shift lever position and there is a demand for downshifting, this will be the case.

In step 424, the shift solenoid valve is controlled according to the downshift schedule. In step 426, it is monitored whether or not the shift is completed. When the shift (downshift) is completed, the DOWN is performed in step 428.
The N shift flag is reset to "0", and step 430
Reset the shift lever position change flag to "0", and in step 432, Gnow (current gear) = Gt
(Target gear) and return.

On the other hand, when both the UP shift flag and the DOWN shift flag are in the reset state, step 4
The routine proceeds from 02, 404 to step 406, where it is determined whether or not the manual downshift (MD) flag is set. If the manual downshift flag is set, proceed to step 422. If the manual downshift flag is not set,
It returns as it is.

Next, details of the contents of the torque control during the manual downshift in step 422 of FIG. 4 will be described with reference to the flowchart of FIG.

When this routine is entered, it is determined in step 602 whether the sub throttle valve 15 is normal, in step 604 it is determined whether the idle speed control (ISC) valve 22 is normal, and in step 606 the throttle Opening Th
Is smaller than a predetermined value Th0 close to zero. In step 606, it is determined whether or not the accelerator opening is fully closed, and thereby whether the engine is in a driving state or a driven state (power off or not) is determined. is there.

If any of the steps 602, 604, and 606 is NO, the torque control during the manual downshift is not executed, so the routine proceeds to step 608.
Reset the manual downshift flag to "0",
Next, at step 610, idle speed control (IS
C) The control value (DI) of the valve is set to the initial setting value, and the control value of the sub throttle valve 15 is set to the initial setting value in step 612. Then, the process proceeds to step 614, and these setting data are transferred to the engine computer (EC
U) Output to 30. In the engine computer 30,
The ISC valve 22 and the sub throttle valve 15 are controlled based on those data.

If the determinations at steps 602, 604, and 606 are all YES, it is determined at step 616 whether the DOWN shift flag is in the set state, and at step 618, the shift lever position change flag is set. Or not. If either is NO, the process proceeds to "end control" after step 632 ("end control" will be described later). Both are YES
In the case of, the process proceeds to “torque control execution process” after step 620.

In step 620, the vehicle speed data is read, and in step 622, the target gear is read. Next, in step 624, the target engine rotation speed Ne ^* is calculated from the vehicle speed data and the target gear position, in step 626 the engine rotation speed Ne is read, and in step 628 the target engine rotation speed Ne ^* and the actual engine rotation speed Ne are set as parameters. Is executed (may be read from the map), and the control value of the ISC valve 22 is calculated. or,
In step 630, the control value of the sub-throttle valve 15 is calculated based on the target engine speed Ne ^* . Here, the maximum value of each control value is set in advance.

In this case, the control value of the sub-throttle valve 15 is a predetermined value on the closing side, and the control value of the ISC valve 22 is a predetermined value on the opening side. Then, the control value calculated in step 614 is output to the engine computer 614. On the engine computer side, the sub-throttle valve is closed and controlled based on the input control value data, and the ISC valve 2
Open and control 2.

Therefore, even if the ISC valve 22 malfunctions in the opening direction, the sub-throttle valve 15 on the downstream side is controlled to the closing side, so that the engine is prevented from being blown up more than necessary.

On the other hand, if the process proceeds to step 632, "end control" is started. This termination control is control at the termination stage of torque control. If the manual downshift (MD) flag is set, step 6
In step 34, the control value of the ISC valve is gradually decreased.

In step 636, the control value (DI) is monitored, and the control value (DI) is set to a preset value (D
I ₀ ), then step 638
At step 640, the manual downshift flag is reset, the sub-throttle valve control value is returned to the initial setting value to end the end control, and the routine proceeds to step 614. After the manual downshift club is reset to 0 in step 638, the process directly proceeds from step 632 to step 424.

Next, an actual operation example will be described with reference to FIG. Note that the katakana code in parentheses in the description indicates a reference point in the drawing.

For example, when the accelerator is released (fully closed = throttle opening is almost zero) while traveling at the third speed in the D range, (a
), The target gear is 4th gear (b). In order to apply the engine brake as it is, when the shift lever is switched from the D range to the 2 range (c), the determination in step 204 of FIG. 3 becomes YES, and the shift lever position change flag is set to “1” in step 206. (D
). Then, if the target gear (Gt) is the second speed (e
), And at the same time, the DOWN shift flag is set (f).

Then, in the shift process of FIG. 4, the process proceeds from step 404 to 418 to 420, the manual downshift flag is set (g), and the torque control for the manual downshift is started.

When the same control is entered, since the DOWN shift flag and the shift lever change flag are in the set state, the process proceeds from steps 616 and 618 in FIG. 5 to step 620. Then, the ISC valve control value and the sub-throttle valve control value are calculated, and the engine computer controls each valve according to the calculated control value. In this case, the sub-throttle valve 15 is controlled to be closed to a predetermined opening (h), and the ISC valve 22
Is controlled to open to a predetermined opening (i).

As a result, the engine speed gradually increases (j). When the shift to the second speed is completed with the increase of the engine rotation speed, step 4 in FIG.
When the determination in step 26 is YES, the process proceeds to step 428, and D
The OWN shift flag is reset (k) and the shift lever position change flag is reset (l).

When the DOWN shift flag is reset, the determination at step 404 in FIG. 4 becomes NO and the routine proceeds to step 406. Since the torque control during the manual downshift has been executed until the last time, the manual downshift flag is "1", and the step 40
The determination result in 6 is YES, and the process proceeds to step 422.

Since the DOWN shift flag is in the reset state this time, the process proceeds from step 616 to step 632 in FIG. If it is not necessary to downshift or upshift for some other reason (such as a change in the target gear) even if the gear shift is not completed, the shift lever position change flag is reset in step 222 of FIG. The determination at step 618 is NO, and the process similarly proceeds to step 632. From this point onward, the "end control" of the torque control is performed.

When the end control after step 632 is entered, the control value of the ISC valve 22 is gradually decreased (m
). The value is gradually decreased until it reaches a predetermined value, and when it reaches the predetermined value, the process proceeds from step 636 to step 638, and the manual downshift flag is reset (n
), The sub-throttle valve 15 is controlled to open to the initial set value (o), and the torque control during the manual downshift is completed.

In the engine control apparatus of the above-described embodiment, the ISC valve 22 is controlled to perform the idle operation at the time of idling. At that time, by keeping the sub-throttle valve 15 closed to the set opening, the ISC It is possible to prevent the engine from blowing up even if the valve system malfunctions. When the engine is not idle, the sub-throttle valve is fully opened, and the drive is controlled to the closed side as required for traction control or the like.

Note that steps 602 and 604 in FIG.
When it is detected that the sub-throttle valve 15 or the ISC valve 22 is abnormal, the driver is notified by an abnormality display.

In this case, when the ISC valve 22 is in the open state and a stick failure occurs, the sub-throttle valve is controlled to be closed at a position where the idle rotation speed is slightly higher than usual during idling. As a result, the driver can detect an abnormality due to the high idle rotation speed.

When the ISC valve 22 has a stick failure at the closed position, the idle speed is controlled by the sub-throttle valve during idling. However, although it is fully opened in practice, the idle speed is low, which is determined by the position of the ISC valve 22.

On the other hand, when the sub-throttle valve 15 is abnormal, the ISC valve 22 performs only idle control and does not perform torque control during manual downshift.

Next, the fail-safe function for the fail mode of the ISC valve 22 and the sub throttle valve 15 will be described.

Here, the results of comparison between the case of the above-described embodiment and the case where the outlet of the ISC valve 22 communicates with the downstream side of the sub-throttle valve 15 (comparative example) are shown in a table. However, in the table, ◯ indicates normal (or that fail-safe is possible), and x indicates abnormal (or fail-safe is impossible). In addition, () in the table indicates the fail mode (fail mode).

ISC valve Sub-throttle valve Comparative example This embodiment × (open) 〇 × 〇 × (closed) 〇 〇 〇 × (open) × (open) × × × (open) × (closed) × 〇 × (closed) ) × (Open) 〇 〇 × (Closed) × (Closed) 〇 〇 〇 × (Open) 〇 〇 〇 × (Closed) 〇 〇

As can be seen from the above table, in the present example, the total fail was reduced to 1/3 as compared with the comparative example. Also, this case is also a case where the ISC valve 22 and the sub-throttle valve 15 become defective only at the time of full-open failure, and is limited to a case that is quite rare in terms of probability. Therefore, it can be seen that this embodiment is effective for fail.

[0062]

As described above, according to the device of the present invention, even if the idle speed control valve malfunctions on the opening side, the sub-throttle valve is controlled on the downstream side to the closing side. , It prevents the engine from blowing up more than necessary. Therefore, during downshifting, the idle speed control valve can be opened and controlled to increase the engine speed, and then downshifting can be performed with high reliability, and gear shift shock can be reduced. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart showing the contents of a shift determination process performed by the apparatus of the above embodiment.

FIG. 4 is a flowchart showing the content of a shift process performed by the apparatus of the above embodiment.

5 is a flowchart showing details of the contents of step 422 of the flowchart of FIG.

FIG. 6 is a characteristic diagram showing a relationship between each input / output data and each flag during the control operation, taking an actual operation as an example.

[Explanation of symbols]

 14 ... Main throttle valve 15 ... Sub throttle valve 19 ... Accelerator pedal 20 ... Actuator 21 ... Bypass passage 22 ... Idle speed control (ISC) valve 51 ... Throttle sensor 52 ... Vehicle speed sensor 53 ... Shift position sensor

Claims (1)

[Claims] 1. A main throttle valve disposed in an intake passage of an engine and interlocking with an accelerator, a sub-throttle valve disposed in series in the intake passage in series with the main throttle valve and driven by an actuator, and the main throttle valve. An idle rotation speed control valve provided in a passage for bypassing the engine, and when the manual downshift operation is performed in a power-off state, the idle rotation speed control valve is controlled to open to a predetermined opening degree to increase the engine output. In the control device for an engine with an automatic transmission, the sub-throttle valve is provided downstream of the main throttle valve, and the downstream end of the bypass passage provided with the idle speed control valve is provided downstream of the main throttle valve. It is connected to the intake passage at a position upstream of the sub-throttle valve, and the power is turned off. When a manual downshift is performed in the fully closed state, the idle rotation speed control valve is opened to a predetermined opening, and the sub-throttle valve is closed to a predetermined opening. Control device for engine with automatic transmission.