JPH03200428A - Crawling travel motion control device of automobile - Google Patents

Abstract

PURPOSE:To carry out smooth crawling travel motion without clutch abrasion and others by controlling a clutch engagement amount so that rotating speed of a transmission input shaft becomes rotating speed for crawling travel motion after securing rotating speed for crawling travel motion in accordance with an axle pedal operating amount. CONSTITUTION:In a system to take out output of an engine 1 provided with a slottle actuator 11 from an output shaft 32 through an abrasion clutch 2 and a transmission 3, the abrasion clutch 2 is controlled to connect and disconnect by a controller 100 through a clutch actuator 21 in accordance with a travelling state of a car. That is, when it is judged as a time not to operate a brake-pedal from output of a brake switch 42, after engine speed for crawling travel motion is secured by controlling the slottle actuator 11 in accordance with an axle pedal operating amount obtained from output of an axle sensor 41, the clutch actuator 11 is controlled and a clutch engagement amount is controlled so that input shaft rotating speed becomes rotating speed for crawling travel motion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a slow-speed running control device for an automobile, and more particularly to a device for controlling slow-speed running of an automobile equipped with a transmission having a friction clutch.

[Prior Art] Conventionally, automobiles having a fluid torque converter in their transmissions have had a unique creep phenomenon, and the driver has been able to easily achieve slow speed driving by operating only the brake pedal.

However, a vehicle equipped with a transmission without a fluid torque converter, that is, a transmission with a friction clutch, does not have slow running phenomenon, that is, creep phenomenon. The disadvantage is that the accelerator pedal, brake pedal, and clutch pedal (some models do not have a clutch pedal) must be operated delicately, and that the operation requires skill.

Therefore, in order to solve the above-mentioned drawbacks, the present applicant has
A device disclosed in Japanese Patent Publication No. -143140 was proposed.

This device controls the clutch in a half-clutch condition on the condition that: ■ the gear of the transmission is in a predetermined low gear, ■ the accelerator pedal is within a slight depression angle, and ■ the vehicle speed is within a set range. Equipped with an automatic clutch, this automatic half-clutch control enabled the driver to run at very low speeds without the need for complicated pedal operations.

Furthermore, in Japanese Patent Application No. 63-321532, the present applicant has disclosed that clutch engagement is set based on information on engine rotation speed, throttle opening, and input shaft rotation speed, as well as related information such as transmission gear stage and brake depression amount. The amount is prepared in advance as a memory map, and this map is used to control the plate clutch to a half-clutch state to prevent the vehicle from creeping (
We are proposing a slow speed control device that allows the vehicle to run at very low speeds.

[Problem to be solved by the invention]

However, in the device disclosed in JP-A-60-143140, the condition settings are limited, and in particular, the accelerator pedal depression amount θ only operates when the accelerator pedal is 0〈θ and the full stroke is 1716. In order to execute this control from a stopped state (usually when the brake pedal is pressed), it is necessary to move the foot from the brake pedal to the accelerator pedal, which is cumbersome and requires only the brake pedal to be turned on and off. The problem was that it was not possible to run at very low speeds.

Furthermore, in the device of Japanese Patent Application No. 63-321532,
■Because it is an open-loop system that determines the clutch engagement amount for slow speed driving from a specified map, even if there are changes in conditions such as differences between paved roads, gravel roads, or snowy roads, or clutch wear and deterioration, There is no need to change the amount of clutch engagement in response to this, ■ it requires a brake depression amount sensor that normal vehicles do not have, which increases costs, and ■ it only controls the flange position. The throttle amount under normal idle conditions may cause jerky running or engine stall (hereinafter simply referred to as engine stall).
■If you press the brake pedal (
Even when the vehicle is stationary (including when the vehicle is stopped), the clutch remains slightly engaged, causing problems such as accelerated wear of the clutch.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a slow speed cruise control device for an automobile that solves these problems.

[Means to solve the problem]

(1) In order to achieve the above object, the vehicle slow running control device according to the present invention includes means for detecting the amount of depression of the brake pedal and the amount of depression of the accelerator pedal, and means for detecting the rotational speed of the engine and the impact shaft, An engine rotation speed adjustment means, a clutch actuator, and when the brake pedal depression is off, the adjustment means is controlled according to the amount of depression of the accelerator pedal to secure an engine rotation speed for slow speed running, and then the engine speed is further controlled for slow speed running. means for controlling the clutch engagement amount by controlling the clutch actuator in order to obtain a target input shaft rotation speed for use.

(2) Also, in the present invention, a vehicle speed detection means is provided in place of the impact shaft rotation speed detection means, and the control means sets a target value that is optimal for slow speed running corresponding to the vehicle speed or the amount of depression of the accelerator pedal. Thus, the amount of clutch engagement can be controlled.

(3) Furthermore, in the present invention, a drive torque detection means is provided in place of the input shaft rotation speed detection means, and the control means sets the drive torque to an optimum target value for slow speed running corresponding to the amount of depression of the accelerator pedal. Thus, the amount of clutch engagement can be controlled.

(4) Furthermore, in the present invention, when the brake pedal is depressed, the control means can control the crunch actuator to bring the clutch to a completely disengaged position.

[For production]

In the present invention, when the brake pedal is not depressed (not depressed), the control means first secures the engine speed corresponding to the detected accelerator pedal depression amount. Then, the target value of the control object that is optimal for slow speed driving corresponding to the amount of accelerator pedal depression, that is, (+) input shaft rotation speed, (
Clutch position operation using the clutch actuator (control of half-clutch state) so that the target value of either 2) vehicle speed or (3) drive torque matches the current value of each.
By doing this, very slow running is realized.

To explain this in more detail, first, the engine speed is
In conventional automobiles that do not run at slow speeds, the rotation speed increases from normal idle rotation in proportion to the amount of depression of the accelerator pedal, as shown in FIG.

However, in the present invention, in order to prevent the engine from stalling even if the clutch position is moved in the tangential direction for slow speed driving, the engine rotation speed adjustment means is used in the area of the accelerator depression amount near the accelerator pedal release position. The engine output is secured by increasing the rotation speed through control.

As shown in Figure 4, the relationship between the target value of the controlled object (input shaft rotational speed, vehicle speed, or drive torque) and the amount of accelerator pedal depression is determined by the accelerator pedal release position in conventional control that does not perform slow speed driving. The value of the controlled object increases linearly in proportion to the amount of accelerator depression from the vicinity, but in the present invention, for slow running control, the value is set so that it is not zero but the optimal target value even at the position where the accelerator pedal is released. .

For this reason, the control means first secures the engine speed corresponding to the accelerator pedal depression amount based on FIG. The amount of clutch engagement is controlled so that

This causes the car to run at a slow speed corresponding to the amount of accelerator pedal depression at that time.

Further, in the present invention (4), when the brake pedal is depressed (pedal depression detected), the control means can control the clutch actuator to bring the clutch to the completely disengaged position. Clutch wear can be kept to a minimum.

〔Example〕

FIG. 1 shows an embodiment of the slight drift control device for an automobile according to the present invention, where l is the engine, and 11 is the throttle of the engine l (in the case of a diesel engine, it is a fuel injection lever, but the following In the embodiment, a throttle actuator is used as an engine rotation speed adjusting means for controlling the engine speed (throttle will be explained as an example), 12 is a rotation speed sensor as a rotation speed detection means of the engine 1, and 2 is a friction clutch (hereinafter simply referred to as a clutch). ), 21 is clutch 2
A clutch actuator 22 is a thalassochi sensor that controls the engaged state L! (Amount of engagement).

Reference numeral 3 denotes a transmission which changes the speed of the engine torque through the engagement of a gear mechanism controlled by the operation of a transmission actiniator 31 to drive an output shaft (not shown) 32; (Input shaft) is provided with a rotation speed sensor 33 as an input shaft rotation speed detection means, and a transmission actuator 3 that selects and controls the gear stage.
1 is provided with a gear stage sensor 34, and the output shaft 32 is provided with a vehicle speed sensor 35 as a vehicle speed detection means and a torque sensor 36 as a drive torque detection means.

Furthermore, 41 is an accelerator sensor as means for detecting the amount of depression of the accelerator pedal, 42 is a brake inch as a means for detecting the amount of depression of the brake pedal, and 5 is a wheel brake mechanism which is activated to maintain braking force when starting on a slope. A power retention actuator 51 is provided.

6 is a road surface slope detection means (not shown) on the vehicle body.
A gradient sensor is attached to the vehicle to detect the gradient of the road surface on which the vehicle is traveling, and 7 is an indicator lamp that displays the slow running state;
8 is a key switch that detects the on/off state of the ignition key; 9 is a slow speed running switch that is turned on when the driver desires slow running (when disabling the braking force retention actuator 51); 10 is a switch near the front and rear of the vehicle; It is a short-range sensor that detects obstacles at a distance.

Further, 100 is a controller composed of a microcomputer, which includes a central control unit for performing arithmetic processing, various memories for storing arithmetic processing procedures, control procedures, control maps, etc. to be described later, a self-diagnosis function, input/output ports, etc. When signals from the various sensors and switches mentioned above are input, commands are issued to the related actuators etc. according to the stored program, and the engine 1
, the clutch 2, the transmission 3, the brake mechanism 5, etc.

FIG. 2 is a diagram showing a flowchart of a program executed by the controller 100, and the operation of the microspeed cruise control device for an automobile shown in FIG. 1 will be described below with reference to the flowchart of FIG. 2.

When this program starts, the controller 100 first turns on the display lamp to inform the driver that slow speed driving control is in progress (step S in Figure 2).
l).

Next, the accelerator pedal depression amount is read from the output of the accelerator sensor 41 and stored in the built-in memory (step S2), and it is determined from this memory whether or not the accelerator pedal is released (accelerator depression amount is zero). Step S3), if it is released, continue to brake switch 4
．． The output of step 2 is read and it is checked whether the brake pedal is depressed (brake switch off) (step S4).

Then, when it is determined that the brake pedal is depressed, clutch actuator 2 is activated since slow speed driving is not necessary.
After operating clutch 1 and moving clutch 2 to the completely disengaged position (
At step S5), the control ends. This is to prevent the engine from stalling during braking and to minimize clutch wear.

On the other hand, when it is determined in step S3 that the accelerator pedal is not released (usually, in this case, the brake pedal is not depressed), or when it is determined that the brake pedal is not depressed in step S4, the controller 100 is slightly confused. Throttle actuator 1 to start driving control
1 to secure the engine rotational speed required as the engine output according to the amount of depression of the accelerator pedal at this time (step S6). That is, as shown in the memory map of FIG. 3 stored in the controller 100, even the accelerator pedal release position is not "O", but the engine rotational speed is increased to an amount appropriate for slow speed running.

And the fourth one also stored in the controller 100.
From the memory map shown in the figure, calculate the target value U of the controlled object that is optimal for slow speed driving corresponding to the amount of accelerator pedal depression (step S7), and then read the current value of the controlled object from the corresponding sensor (step S7). S8).

Here, as shown in FIG. 4, the target value U of the controlled object in the present invention is different from the conventional case where slow speed running control is not performed in that the target value does not become zero even if the accelerator pedal depression amount is zero. If the object to be controlled is the rotation speed of the input shaft, the rotation speed should be 100 to 300 rpm.

Furthermore, to explain how to read the current value V of the controlled object, in the present invention, the controlled object is (1) the input shaft rotation speed from the rotation speed sensor 33, (2) the vehicle speed from the vehicle speed sensor 35, and (3) Any drive torque from the torque sensor 36 may be used, and its current value V is read.

After reading the current value V in step S8, the controller 100 compares the current value V with the target value U calculated in step S7 (step S9). Then, when target value U>current value V, the clutch actuator 21 is operated to move the clutch 2 by a predetermined amount in the tangential direction (
same step 520).

On the other hand, when the target value u is equal to the current value V, the clutch 2 is moved in the disengaged direction by a predetermined amount (step 511). Further, when U=V, the current position of the clutch is held and this program ends.

Here, the comparison between target value U and current value V may be controlled strictly, or conversely, if the difference between U and V is small, control may be performed to ignore the difference and consider them to be equal. .

Here, when the vehicle travels on a road surface with a slope, control that takes this point into consideration is required.

Accordingly, in the present invention, the control of the program shown in FIG. 2 is further corrected as follows based on the output of the slope sensor 6, to perform slow speed driving control that is optimal for the slope of the road surface on which the vehicle is traveling.

■The control cycle (program cycle) is made variable depending on the road surface slope.

This is because when driving uphill, the vehicle may slide if the drive torque is not increased quickly, so to prevent this, the control cycle is made earlier than when driving on a flat road or downhill.
The control period for executing the routine shown in FIG. 2 is usually about 20 or so, but the control period is about 172.

■Correct the target value of the controlled object according to the road surface slope.

This is for the same reason as mentioned in ■ above, and in order to increase the drive torque faster when going uphill, the step S is faster than when going downhill or on a flat road.
This is to slightly increase the target value U of the controlled object in step 7.

■Correct the amount of clutch position operation depending on the road slope.

This is also similar to the above-mentioned case (2), in order to increase the drive torque quickly when the vehicle is going uphill, the amount of clutch position operation in step SIO is increased compared to when the vehicle is going downhill.

It goes without saying that only one of each of the above controls (1) to (2) may be included in the control, or several may be included in the control at the same time.

In the above case, the conditions for entering the control routine in Figure 2 are not a particular issue, but as shown in Figure 5, when all of the following conditions are satisfied, the aforementioned slow running mode is executed. is necessary.

■When the ignition key is determined to be on based on the output of key switch 8.

This is to avoid the risk of the vehicle starting to move on its own due to slow speed control, since there may be an abnormal situation where the engine 1 continues to rotate even when the ignition key is off.

■Engine 1 must be running.

This is a matter of course, but in reality, it is usually determined that the engine is running when the engine speed is above a set value of 500 to 700 rpm.

■The diagnosis result by the self-diagnosis function built into the controller 100 is normal.

This judgment is made because if there is an abnormality in the sensors, actuators, controllers, etc. necessary for slow-speed running control, performing slow-speed running control will cause danger. Normally, self-diagnosis is performed within the controller 100 from memory (not shown) and input values from various sensors.
Judgment will be made based on the results.

■When the vehicle speed is higher than the set value (approximately 10km/h is appropriate).

This is because if slow speed control is used when the vehicle speed is high, fuel efficiency will deteriorate and engine braking will become less effective.

■The gear position is the starting position.

This is the starting gear (
This is because it is normally only needed when in first or reverse gear in a passenger car, and second gear in a trunk.

Further, since this prevents the vehicle from running at a slow speed except in the starting gear, it is possible to avoid shortening of clutch life and deterioration of fuel efficiency due to heavy use of the clutch in a partially engaged state.

On the other hand, as shown in FIG. 6, if any one of the conditions shown in FIG. 5 is unsatisfied, it is necessary to cancel the slow running mode.

Furthermore, in addition to the conditions shown in FIG. 5, as shown in FIG. 7, the state of the slow speed running switch 9, which is operated only when the driver wants to drive at slow speed, or when the amount of accelerator depression is less than the set value, allows slow speed running. mode.

That is, ■The slow running switch 9 must be on.

By adding to the setting conditions that the driver turn on the slow-speed driving switch 9 when slow-speed driving mode is required, such as during traffic jams or when parking in a garage, the driver's will can be respected, reducing clutch life and reducing fuel consumption. deterioration can be prevented.

■The amount of accelerator pedal depression is less than the set value.

This assumes that when the amount of accelerator pedal depression is small, it means that the driver wants to drive at a slow speed, and adds to the setting condition that the amount of accelerator pedal depression is less than a set value, and the set value is based on the amount of accelerator pedal stroke. Approximately one-third
The degree is appropriate.

Accordingly, as shown in FIG. 8, it is necessary to cancel the slow running mode when any one of the cancellation conditions shown in FIG. 7 or any of the following is satisfied.

That is, ■The slow running switch 9 must be turned off.

This is because the clutch is often used in a partially engaged state in low-speed driving mode, resulting in a slow start response.

Therefore, when the driver wants to start or accelerate quickly, such as when entering a highway or entering a wide street, the driver can cancel the slow speed mode by turning off the slow speed switch 9.

■The amount of accelerator pedal depression is greater than or equal to the set value.

This assumes that when the driver depresses the accelerator pedal significantly, it is the time to start or accelerate the vehicle, and cancels slow running mode when the amount of accelerator pedal depression is equal to or greater than a set value.

By performing the above control, it is determined whether the driver wants to drive at a slow speed or if he wants to start and accelerate quickly, and based on that judgment, the slow speed mode is set or canceled, thereby controlling the drive to suit the driver's will. becomes possible.

On the other hand, as shown in FIG. 1, a short-range sensor 10 is provided to detect obstacles in a short distance in front of and behind the vehicle, and as shown in FIG. 9, all of the slow running mode setting conditions shown in FIG. 5 are satisfied. In addition, the slow speed driving mode may be set only when an obstacle (another vehicle, a wall, etc.) is detected in the direction of travel of the vehicle.

This is because the situations that require slow-speed driving control include when driving on a congested road or when parking in a garage, and in both cases there are obstacles nearby.
This is because the vehicle is detected at 0 and the slow running mode is set only when an obstacle is present.

As a result, the vehicle automatically enters the slow speed mode only when it is necessary, thereby freeing the driver from the trouble of performing a switch neck operation. Additionally, when there is an obstacle nearby, the vehicle automatically enters a low-speed driving control state, which prevents the driver from noticing the obstacle and starting the vehicle at a slow speed, thereby avoiding the risk of a collision.

In this case, when detecting an obstacle, the direction of travel of the vehicle can be determined from the gear position.
It is preferable to obtain information from a short-range sensor at the front of the vehicle when moving forward, and from a short-range sensor at the rear of the vehicle when reversing.

Further, the detection area of the sensor is suitably equal to that of the vehicle so as not to detect vehicles in adjacent lanes, oncoming vehicles, guardrails, etc. If the detection distance is short, the brake must be applied immediately after detection, and there is no point in running at a slow speed, so this distance needs to be 5 meters or more.

In addition, the present invention can also be applied to automobiles equipped with a braking force retention device. In this case, it is necessary to turn on the slow running switch 9 as shown in FIG.

This operation will be explained based on the flowchart shown in FIG. Note that steps 5IOI to 5104 in this program routine are steps SL and S shown in FIG.
3 to S5, and this routine is continued to step S6 in FIG.

After the clutch is disengaged in step 5104 to prevent engine stalling and clutch wear, the controller 100 checks whether the vehicle is stopped based on the output of the vehicle speed sensor 35 (step 5105), and if it is determined that the vehicle is stopped, the controller 100 determines whether the vehicle is stopped or not. Activate the holding actuator 51 (see Figure 2) (
In step 7 (step 5106), the brake mechanism 5 is operated to bring the braking force into a holding state (H3A) and the program ends.

If rN is 1 in step 5102 or 5103, the controller 100 checks whether the slow running switch 9 is on (step 5107), and if it is on, the process proceeds to step 5106, but if it is off, it continues to maintain the braking force. Check whether the actuator 51 is in operation (step 3108), and if it is not in operation, proceed to step 5113.

If it is determined in step 3108 that the braking force holding actuator 51 is in operation, then the current value α of the driving torque or clutch position is detected from either the torque sensor 36 or the clutch sensor 22 (step 5109),
Compare this current value α and the set value β when the braking force is released (
same step 5109). Here, the set value β is a value that corresponds to a driving torque to the extent that the vehicle does not slide down even on a slight slope.

When α<β, the driving torque is insufficient, so the driving force is increased by operating the clutch actuator 21 and moving the clutch position a little in the tangential direction (
The same step Sl 11) is in this case step 51
Since the clutch is completely disengaged in step 5104 as a prerequisite for the braking force holding actuator 51 to be activated in step 06, step 5111 will be repeated several times.

Then, when the clutch is gradually connected, α≧β, and since sufficient driving torque is obtained at this time, the braking force holding actuator 51 is deenergized and the holding braking force is released. While the vehicle is maintained in a state where it does not slide, the amount of depression of the accelerator pedal is detected from the output of the accelerator sensor 41 and stored in the memory (step 5113 in the same step).

After this, the process advances to step S6 in FIG. 2 to execute slow running control, but by performing the control shown in FIG. Smooth, low-speed driving can be achieved simply by operating the driver's brake pedal.

〔Effect of the invention〕

As described above, in the slight drift control device for a motor vehicle according to the present invention, after securing the engine speed for slow speed travel in accordance with the amount of depression of the accelerator pedal when the brake pedal is depressed, Since the clutch actuator is controlled to control the amount of clutch engagement by controlling the clutch actuator 4B so that the input shaft rotational speed (or vehicle speed or driving torque) is maintained, the following unique effects can be obtained.

) You can drive at slow speeds by simply turning the brake pedal on and off.

11) Since the controlled objects (input shaft rotational speed, vehicle speed, and drive torque) are controlled in a closed loop, it is possible to drive at very low speeds in response to road conditions and clutch wear conditions.

iii) Since both the clutch position and engine output are controlled, there is no risk of jerky running or engine stalling.

iv) When the brake pedal is depressed, the clutch is completely disengaged and the half-clutch state is not frequently used, thereby reducing clutch wear, deterioration of fuel efficiency, and deterioration of engine braking effectiveness.

[Brief explanation of drawings]

FIG. 1 is a hardware configuration diagram showing an embodiment of the vehicle slight wander control device according to the present invention, FIG. 2 is a flowchart diagram of a program executed by the controller of the present invention, and the third panel is: A graph diagram showing the relationship between the amount of accelerator pedal depression and the engine rotation speed (engine output), FIG. FIG. 9 is a diagram explaining the slow running mode setting conditions in the present invention, and FIG.
The figure is a flowchart of a program involving a braking force holding operation (ISA) executed by the controller of the present invention. In Fig. 1, 1 is an engine, 2 is a friction clutch,
11 is a throttle actuator, 12 is an engine rotation speed sensor, 21 is a clutch actuator, 33 is an input shaft rotation speed sensor, 34 is a gear stage sensor, 3
5 is a vehicle speed sensor, 36 is a drive torque sensor, 41 is an accelerator sensor, 42 is a brake switch, 9 is a low speed running switch, and 100 is a controller, respectively. In the figures, the same symbols indicate the same or equivalent parts. agent

Claims (4)

[Claims] (1) Each detection means for the amount of brake pedal depression and accelerator pedal depression, each rotation speed detection means for the engine and input shaft, the engine rotation speed adjustment means, the clutch actuator, and the accelerator when the brake pedal depression is off. In accordance with the amount of pedal depression, the adjusting means is controlled to ensure the engine rotation speed for slow speed running, and then the clutch actuator is controlled to adjust the clutch engagement amount in order to obtain the target input shaft rotation speed for slow speed running. A slow speed running control device for an automobile, comprising: means for controlling. (2) A vehicle speed detection means is provided in place of the input shaft rotation speed detection means, and the control means adjusts the clutch engagement amount so that the vehicle speed becomes an optimal target value for slow-speed driving corresponding to the accelerator pedal depression amount. 2. The slow speed running control device for a motor vehicle according to claim 1, wherein (3) A drive torque detection means is provided in place of the input shaft rotation speed detection means, and the control means engages the clutch so that the drive torque reaches a target value optimal for slow speed running corresponding to the amount of depression of the accelerator pedal. 2. The micro-speed running control device for a motor vehicle according to claim 1, wherein the control device controls the amount. (4) When the brake pedal is depressed, the control means controls the clutch actuator to bring the clutch to a completely disengaged position. Control device.