JPH06173729A - Control device for vehicle provided with automatic transmission - Google Patents

Abstract

PURPOSE:To suppress shock when a vehicle is stopped in its condition in which an automatic transmission is in running range, and eliminate uncomfortable feeling accompanying with the shock. CONSTITUTION:An automatic transmission 13 is connected to an engine 1 through a torque converter 12. A car speed sensor 17 for detecting speed of a vehicle and a range switch 18 for detecting a selected range are provided in the automatic transmission 13. A brake switch 24 is arranged on the brake pedal 23 of a brake device 22. In an ECU 25, it is judged on the basis of signals detected by the brake switch 24 and the vehicle speed sensor 17 that the vehicle is in just before stopping condition. And also, in the ECU 25, it is detected by the range switch 18 that the automatic transmission 13 is in a running range, and output torque of the engine 1 is reduced to less than output torque at the time of normal condition until the vehicle is stopped when it is judged that the vehicle is in just before stopping condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention comprises an automatic transmission,
The present invention relates to a control device used in a vehicle that is driven by the power of an engine.

[0002]

2. Description of the Related Art Conventionally, various control devices for reducing the creep torque of an automatic transmission have been disclosed. For example, in the control device disclosed in Japanese Patent Laid-Open No. 60-237254, the automatic transmission is in the traveling range, and
When the vehicle is at a standstill, the idle speed control and the creep torque control are selectively carried out so as to achieve both the adjustment of the idle speed and the reduction of the creep torque.

[0003]

However, although the above-mentioned conventional control device has the effect of reducing the creep torque when the vehicle is stopped, it still has a problem of shock caused by the creep torque when the vehicle is stopped. It was left. In other words, in a vehicle equipped with an automatic transmission, when the automatic transmission stops the vehicle in a running range, a brake pedal depressing force that resists creep torque is required, and it is difficult to adjust the amount of depression.
As a result, if the brake pedal is depressed too much when the vehicle is stopped, a shock is generated, which gives an occupant of the vehicle discomfort.

The present invention has been made in view of the above problems, and an object thereof is to suppress a shock when the vehicle stops in a state where the automatic transmission is in the traveling range, and to reduce the shock. An object of the present invention is to provide a vehicle control device provided with an automatic transmission that can eliminate the discomfort that accompanies it.

[0005]

In order to achieve the above object, the present invention is used in a vehicle equipped with an automatic transmission M1 as shown in FIG. 6 and driven by the power of an engine M2. An automatic transmission range detecting means M3 for detecting a selection range of the automatic transmission M1, a braking means M5 for stopping the vehicle by depressing a brake pedal M4, and a vehicle speed sensor M6 for detecting the speed of the vehicle, Brake pedal M4 of the brake means M5
Based on the state of depression of the vehicle and the detection result of the vehicle speed sensor M6, the vehicle immediately before stop determining unit M7 that determines that the vehicle is in the state immediately before stop, and the automatic transmission M1 by the automatic transmission range detecting unit M3. Is detected to be in the traveling range, and when the vehicle immediately before stop is determined by the vehicle immediately before stop determination unit M7, at least until the vehicle is stopped, the engine M2 is stopped. It is the gist of the present invention to provide the output torque reducing means M8 for reducing the output torque of the above-mentioned output torque from the output torque at the normal time.

[0006]

According to the above configuration, the vehicle immediately before stop determining means M7 determines that the vehicle is in the immediately before stop state based on the depression state of the brake pedal M4 of the brake means M5 and the detection result by the vehicle speed sensor M6. . Further, when the automatic transmission range detection means M3 detects that the automatic transmission M1 is in the traveling range and the vehicle immediately before stop state determination means M7 determines that the vehicle is immediately before stop, the output torque is output. The reducing means M8 reduces the output torque of the engine M2 below the output torque during normal operation at least until the vehicle is stopped.

As described above, when the vehicle stops while the automatic transmission M1 is in the traveling range, the output torque, that is, the creep torque is reduced. As a result, the depression of the brake pedal M4 that is depressed against the creep torque can be weakened, and a shock due to the depression of the brake pedal M4 when the vehicle is stopped is prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an engine control system in the present embodiment. Intake pipe 2 for engine 1
And a surge tank 3 is provided in the middle of the intake pipe 2. In the intake pipe 2, a throttle valve 4 for adjusting the amount of air taken into the intake pipe 2 is arranged on the upstream side of the surge tank 3. The throttle valve 4 is provided with an idle switch 5 for detecting that the valve 4 is in a fully closed state (idle state), and the switch 5 outputs an ON signal when an idle is detected. . An air cleaner 6 is arranged at the most upstream part of the intake pipe 2.

Further, the intake pipe 2 is provided with a bypass passage 7 that bypasses the throttle valve 4 and connects the upstream side of the throttle valve 4 and the surge tank 3. An idle speed control valve (hereinafter referred to as ISC valve) 8 is provided in the bypass passage 7. ISC
The valve 8 is always biased by a spring (not shown) so that the valve body 8a closes the seat portion 8b.
The valve body 8a opens the seat portion 8b by exciting c. Therefore, the bypass passage 7 is opened by exciting the coil 8c of the ISC valve 8, and the bypass passage 7 is closed by demagnetizing the coil 8c.

The engine 1 is also provided with an engine speed sensor 9 for detecting the engine speed and a water temperature sensor 10 for detecting the temperature of the engine cooling water.

Further, an automatic transmission 13 is connected to the engine 1 via a torque converter 12. The torque converter 12 transmits the rotation of a crankshaft (not shown) of the engine 1 to the input shaft 14 and the clutch shaft 15 to the output shaft 16. A vehicle speed sensor 17 for detecting the speed (vehicle speed) on the output side of the automatic transmission 13 is provided in the middle of the output shaft 16. Further, the automatic transmission 13 is provided with a range switch 18 as an automatic transmission range detecting means for outputting a signal corresponding to a selected range (running range, neutral range, etc.) of the transmission 13.

A propeller shaft 19 and a differential gear 20 are connected to the output shaft 16, and the rotation of the output shaft 16 is transmitted to the left and right drive wheels 21 via these components.

Brake device 22 as braking means
Is for stopping the vehicle by depressing the brake pedal 23. The brake device 22 is provided with a brake switch 24 that outputs an on / off signal according to the amount of depression of the brake pedal 23. . Then, when the brake pedal 23 is depressed beyond a predetermined amount, the brake switch 24 outputs an ON signal.

Electronic control unit (hereinafter referred to as ECU) 25
Is a logical operation circuit including a well-known CPU, ROM, RAM, input / output port and the like. Various sensors (engine speed sensor 9, water temperature sensor 10, and vehicle speed sensor 17) are connected to the ECU 25. Various switches (idle switch 5, brake switch 24, and range switch 18) are connected to the ECU 25. In the present embodiment, the ECU 25 constitutes the immediately preceding vehicle stop state determination means and the output torque reduction means.

Next, the operation of this embodiment will be described with reference to the flow charts of FIGS. 2 to 4 and the time chart of FIG. FIG. 2 is a flowchart showing an idle speed control routine, which is executed by the ECU 25 at predetermined time intervals.

In FIG. 2, the ECU 25 first determines in step 101 whether or not the output signal from the idle switch 5 is currently on. If the output signal from the idle switch 5 is off (before the timing of t1 in FIG. 5), the ECU 25 proceeds to step 102,
Various flags to be described later are initialized and the routine is ended once. That is, if the idle signal is off, the ECU 25 does not execute the idle speed control.

If the output signal from the idle switch 5 is ON at step 101 (after the timing of t1 in FIG. 5), the ECU 25 proceeds to step 103 to read the operating state of the engine 1. Specifically, EC
U25 is an engine speed sensor 9 and a water temperature sensor 10.
The engine speed Ne, the cooling water temperature Tw, and the like are detected based on output signals from the above.

Subsequently, the ECU 25 determines in step 104 that
The target idle speed XNe is calculated based on the operating state of the engine 1 read in step 103. That is, the ECU 25 calculates the target idle rotation speed XNe by adding the base value of the target rotation speed stored in the ECU 25 to the cooling water temperature Tw and the correction according to the load of the headlight, the air conditioner, and the like.

In a succeeding step 105, the ECU 25 executes a target control rotation speed setting routine shown in FIG.
A target control rotation speed NT which is a target control amount of the C valve 8 is set. Thereafter, in step 106, the ECU 25 sets the ISC valve 8 to set the engine speed Ne to the target control speed NT.
Control the drive of.

Next, the target control rotational speed setting routine of step 105 of FIG. 2 will be described with reference to the flowchart of FIG. In FIG. 3, the ECU 25 determines in step 201 that the engine speed return determination flag F2, which will be described later.
Is reset (F2 = 0).
Further, in the subsequent step 202, the ECU 25 determines whether or not the immediately preceding vehicle stop state determination flag F1 is set (F1 = 1).

Incidentally, this state determination flag F immediately before the vehicle is stopped.
1 is set by the vehicle immediately before stopping state determination routine of FIG. 4, F1 = 1 indicates that the vehicle is in the state immediately before stopping, and F1 = 0 indicates that the vehicle is not in the state immediately before stopping. .

Here, the immediately preceding vehicle stop state determination routine of FIG. 4 will be described. The routine of FIG. 4 is executed by the ECU 25 at predetermined time intervals. In FIG. 4, the ECU 25 determines the range switch 1 in step 301.
Based on the output signal of No. 8, it is determined whether the selected range of the automatic transmission 13 is the traveling range (D range). or,
The ECU 25 determines the brake switch 24 in step 302.
It is determined whether the output signal from is on. Further, the ECU 25 determines in step 303 that the vehicle speed sensor 1
It is determined whether the vehicle speed Vc detected in 7 is equal to or lower than a minute predetermined speed Vk (for example, 5 km / h).

If any of the steps 301 to 303 is negatively determined, the ECU 25 determines that the step 30
5, the state determination flag F1 immediately before the vehicle is stopped is reset (F1 = 0), and the routine ends. That is, before the timing of t3 in FIG. 5, the vehicle immediately before stop state determination flag F1 is held in the reset state.

On the other hand, if all of the steps 301 to 303 are affirmatively determined, the ECU 25 proceeds to step 304 and sets the state determination flag F1 immediately before the vehicle is stopped (F1 =
1) Then, the same routine is finished. That is, the automatic transmission 1
When the brake range is turned on at the timing of t2 in FIG. 5 when the selected range of 3 is the traveling range, the vehicle speed Vc is gradually reduced thereafter. When the vehicle speed Vc becomes equal to or lower than the predetermined speed Vk at the timing of t3, the immediately-before-vehicle-state determination flag F1 is set.

In the target control speed setting routine of FIG. 3, both the flags F1 and F2 are reset (F1 = 0, F2 = 0) before the timing of t3 in FIG. , Step 201 → 202
→ Transfer like 203. ECU 25 executes step 2
In 03, the target idle speed XNe calculated in step 104 of FIG. 2 is set as the target control speed NT, and then the routine ends.

On the other hand, when the immediately preceding vehicle stop state determination flag F1 is set (F = 1) at the timing of t3 in FIG. 5, the ECU 25 shifts to step 201 → 202 → 204. Then, the ECU 25 executes step 20.
4, the vehicle speed Vc detected by the vehicle speed sensor 17 is "0"
Or not, that is, whether or not the vehicle is stopped. At this time, at the timing of t3 to t4 in FIG. 5, since the vehicle is traveling at a very small speed (0 <Vc ≦ Vk), the ECU 25 makes a negative determination in step 204 and proceeds to step 205. Then, the ECU 25 determines in step 205 from the target idle speed XNe the predetermined value A
After the value obtained by subtracting is the target control rotation speed NT (= XNe-A), the routine is ended. The predetermined value A is a numerical value necessary for reducing the shock when the vehicle is stopped, and here, it is experimentally obtained in advance.

As described above, when the vehicle is in the state immediately before the stop (timing from t3 to t4 in FIG. 5), the target control amount of the ISC valve 8 is a value lower than the value corresponding to the normal target idle speed XNe. Is set to. Then, until it is determined that the vehicle is stopped, in step 106 of FIG. 2, the ISC valve 8 is controlled with the low target value. As a result,
At the timing of t3 to t4, the output torque (creep torque) of the engine 1 is controlled to a torque lower than the normal time, and the shock when the vehicle is stopped is suppressed.

Thereafter, when the vehicle speed Vc becomes "0" at the timing of t4 in FIG. 5, that is, when it is determined that the vehicle is stopped, the ECU 25 causes the ECU 25 to execute steps 206 to 206.
Move to. Then, the ECU 25 sets the value obtained by adding the predetermined value a to the previous target control rotation speed NT in step 206 as the target control rotation speed NT (= NT + a). The predetermined value a is a value smaller than the above-mentioned predetermined value A.

In the following step 207, the ECU 25 determines that the target control speed NT at that time is equal to or higher than the target idle speed XNe calculated in step 104 of FIG. 2 (NT ≧ XN.
e) is determined. That is, the ECU 25
It is determined whether or not the target control speed NT reduced by the predetermined value A immediately before the vehicle is stopped has returned to the normal target idle speed XNe. If the target control speed NT has not returned to the target idle speed XNe (NT <XN
e), the ECU 25 ends the routine as it is.

Thus, immediately after the vehicle stops (t4 in FIG. 5).
The target control rotation speed NT is gradually returned to the target idle rotation speed XNe at the timing of (~ t5).

Then, at the timing of t5 in FIG. 5, the target control rotational speed NT returns to the target idle rotational speed XNe (N
When T ≧ XNe), the ECU 25 proceeds from step 207 to step 208, sets the engine speed return determination flag F2 (F2 = 1), and ends the routine.

After that, in the routine of FIG. 3, since the engine speed return determination flag F2 is set (F2 = 1), the ECU 25 shifts from step 201 to step 203 to perform normal idle speed control. Run.

As described above in detail, in the control device of this embodiment, based on the depression state of the brake pedal 23 of the brake device 22 and the detection result of the vehicle speed sensor 17,
It is now possible to determine that the vehicle is in a state just before stopping.
Further, when the range switch 18 detects that the automatic transmission 13 is in the traveling range and it is determined that the vehicle is in a state immediately before the stop, the output torque of the engine 1 is stopped until the vehicle is stopped. The (creep torque) is made lower than the output torque at the normal time, and then gradually returned to the normal output torque.

According to the above construction, when the vehicle stops while the automatic transmission 13 is in the traveling range, the output torque, that is, the creep torque is reduced. As a result, the brake pedal 23 is depressed against the creep torque.
The depression of the vehicle can be weakened, and the shock due to the depression of the brake pedal 23 when the vehicle is stopped can be prevented, and the discomfort given to the passenger can be suppressed.

In the above embodiment, the idle speed control is carried out by using the air bypass type ISC valve 8.
Connect the control actuator to the throttle valve 4,
The actuator may adjust the opening of the throttle valve to control the idle speed.

In the above embodiment, the idle speed control by the ISC valve 8 is used to reduce the output torque.
This may be replaced with ignition retard control.

[0037]

According to the present invention, the shock when the vehicle stops while the automatic transmission is in the traveling range is suppressed,
It has an excellent effect of eliminating discomfort associated with the shock.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a control device according to an embodiment.

FIG. 2 is a flowchart showing an idle speed control routine.

FIG. 3 is a flowchart showing a target control rotation speed setting routine.

FIG. 4 is a flowchart showing a state determination routine immediately before vehicle stop.

FIG. 5 is a time chart for explaining the flowcharts of FIGS.

FIG. 6 is a block diagram corresponding to a claim.

[Explanation of symbols]

1 ... Engine, 13 ... Automatic transmission, 17 ... Vehicle speed sensor,
18 ... Range switch as automatic transmission range detecting means, 22 ... Brake device as braking means, 23 ...
Brake pedal, 25 ... ECU as a state determination means and output torque reduction means immediately before the vehicle is stopped.

Claims (1)

[Claims] 1. An automatic transmission, which is used for a vehicle traveling by the power of an engine, comprising: an automatic transmission range detecting means for detecting a selection range of the automatic transmission; and a brake pedal depression operation. Brake means for stopping the vehicle, a vehicle speed sensor for detecting the speed of the vehicle, based on the depression state of the brake pedal of the brake means and the detection result by the vehicle speed sensor, the vehicle is in a state just before stopping The vehicle immediately before stopping state determining means for determining and the automatic transmission range detecting means detect that the automatic transmission is in the traveling range, and the immediately before vehicle stopping state determining means determines that the vehicle is in the immediately before stopping state. If it is determined that the output torque of the engine is normal at least until the vehicle is stopped. Control device for a vehicle with an automatic transmission, characterized in that an output torque reducing means also reduces the output torque.