JP2002021888A - Start clutch control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission capable of relaxing an engaging shock when engaging a start clutch by smoothly engaging the start clutch when starting, and to relax shock in engaging and releasing the clutch when accelerating. SOLUTION: When starting, the engagement of the start clutch is controlled so that the rotating speed of a driving wheel output shaft connected to the start clutch is the target engine speed of clutch engagement determined by throttle opening, while maintaining engine speed determined by throttle opening set by a driver. The difference between engine torque (engine speed) and clutch torque (the rotating speed of the driving wheel output shaft) is thus eliminated to prevent the generation of step difference of torque. Further, even in the slip state of the start clutch, the increment torque of the start clutch is smoothly changed, so that the generated torque is smoothly changed to relax the engaging shock when engaging the start clutch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of transmission and disconnection of a clutch of a transmission when a vehicle starts.

[0002]

2. Description of the Related Art Automobiles with a manual transmission have better fuel efficiency than those equipped with a transmission using a torque converter. However, it is difficult to operate the clutch and the accelerator at the start. If the clutch and the accelerator are not cooperatively operated at the time of starting, a large shock occurs at the time of clutch engagement, or if the clutch pressure is insufficient, the engine speed rapidly increases, a so-called blow-up phenomenon occurs. In addition, the engine may stop when the clutch is suddenly engaged while the engine speed is not sufficient, or when the vehicle is started on a slope, so-called engine stall may occur.

In order to solve these problems, recently, a system has been developed in which clutches and gear changes are automated using a mechanism of a manual transmission. Particularly, a technique for clutch control at the time of starting is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-11720.

[0004]

In such a conventional example, the connection speed for engaging and disengaging the clutch is determined based on the difference between the engine speed and the speed of the transmission (drive wheel output shaft). ing. In this method, a change in the friction coefficient of the clutch is detected, and the change in the friction coefficient is responded to by changing the connection speed of the clutch. But,
In this conventional example, since the change in torque generated at the time of starting is not considered at all, the starting clutch is not engaged, and a torque fluctuation occurs when the starting clutch is slipping or when the starting clutch is engaged. A shock may occur, causing the occupant to feel uncomfortable.

An object of the present invention is to provide an automatic transmission capable of smoothly engaging a starting clutch at the time of starting and reducing a feeling of engagement shock when the starting clutch is engaged.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for controlling the starting clutch while keeping the engine speed determined by the throttle opening set by the driver within a certain range at the time of starting. The engagement of the starting clutch is controlled such that the rotational speed of the drive wheel output shaft to be connected becomes the target engine rotational speed for clutch engagement determined by the throttle opening. In this way, there is no difference between the engine torque (engine speed) and the clutch torque (speed of the drive wheel output shaft) so that a torque step does not occur, and the vehicle starts even when the starting clutch is slipping. By smoothly changing the incremental torque of the clutch, the generated torque is also changed smoothly, so that the sense of engagement shock when the start clutch is engaged is reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a clutch control device according to the present invention will be described below.

FIG. 1 is a block diagram showing a signal flow and processing of a clutch control device according to an embodiment of the present invention.

In FIG. 1, reference numeral 101 denotes a target engine speed calculating means. The target engine speed calculating means 101 receives a throttle opening TVO.
When the throttle opening TVO is input, the engagement target engine speed Ntg corresponding to the throttle opening input value is set.
It has a function of outputting t.

Reference numeral 102 denotes a subtraction means.
Performs a subtraction process between the engagement target engine speed Ntgt input from the engagement target engine speed calculation means 101 and the current engine speed Ne, and subtracts the current engine speed Ne from the engagement target engine speed Ntgt. A rotation speed Ngap, which is a difference between the engagement target engine rotation speed and the current engine rotation speed obtained as described above, is output.

Reference numeral 103 denotes clutch torque increment calculating means.
The clutch target increase engine speed Nt output from the subtraction unit 102 is provided to the clutch torque increment calculation unit 103.
gt and the difference Ngap between the current engine speed Ne, the acceleration obtained by differentiating the vehicle speed by the differentiating means 107 and the estimated running load obtained by inputting the clutch torque command value Tc to the running load estimating means 108 are input. ing. The clutch torque increment calculating means 103 calculates and outputs a clutch torque increment ΔT to be applied when the starting clutch is engaged.

Reference numeral 104 denotes an engine torque estimating means. The engine torque estimating means 104 includes a throttle opening TV.
O and the engine speed Ne are input, and the estimated engine torque Te obtained by estimating the engine torque from the engine torque characteristics is output to the adding means 105.

Reference numeral 105 denotes an adding means.
Is obtained by adding the rotation speed Ngap of the difference between the engagement target engine rotation speed Ntgt output from the clutch torque increment calculation means 103 and the current engine rotation speed Ne, and the estimated engine torque Te output from the engine torque estimation means 104. This is output as the clutch torque command value Tc.

Numeral 106 denotes a clutch pressure converting means. The clutch pressure converting means 106 receives the clutch torque command value Tc output from the adding means 105, converts it into a clutch pressure command value Pc, and outputs it. That is, the clutch pressure command value Pe output from the clutch pressure conversion means 106 becomes a control signal for the actuator that operates the transmission clutch.

Reference numeral 107 denotes a differentiating means.
Is obtained by differentiating the vehicle speed to obtain an acceleration. The obtained acceleration is output to the traveling load estimating means 108. The traveling load estimating means 108 calculates an estimated traveling load when the vehicle travels from the vehicle acceleration and the torque command value Tc of the starting clutch. The estimated traveling load obtained by the traveling load estimating means 108 is Clutch torque increment calculation means 1
03, the clutch torque increment calculation means 103 calculates a clutch torque increment ΔT to be applied when the starting clutch is engaged.

FIG. 2 shows a configuration of a power system (power train) of an automobile to which the present invention is applied.

In the figure, the intake air amount of the engine 202 is increased or decreased by a throttle valve 201, and the fuel injection amount is controlled by the increase or decrease of the intake air amount, thereby controlling the engine torque. The engine torque of the engine 202 is transmitted to the starting clutch 203. The clutch pressure of the start clutch 203 is increased or decreased by the clutch pressure control device 205, and the engagement, slippage,
Release is controlled. That is, transmission of power to the transmission 204 is controlled by increasing or decreasing the clutch pressure of the clutch pressure control device 205.

The transmission 204 includes a starting clutch 20.
3, the torque is transmitted, and the input / output ratio between the torque and the rotational speed is determined. The torque converted by the transmission 204 is further transmitted to tires (drive wheels) via a propeller shaft, a differential gear, and a drive shaft.

The clutch pressure control device 205 is provided in the transmission control device 206. The clutch pressure control device 205 receives the throttle opening TVO from the throttle valve 201 and the engine speed Ne from the engine 202. Then, the input rotation speed of the transmission is input from the transmission 204, and from these values, a clutch pressure command value to be output to the starting clutch 203 is calculated and output, and the engagement, slip, and release of the starting clutch 203 are controlled. I have.

FIG. 3 is a state transition diagram of clutch control at the start of an automobile to which the embodiment of the present invention is applied.

In the figure, a state 301 shows a state in which the clutch is released. From this state 301, when the accelerator pedal is depressed and the gear selection lever is not neutral, the state transits to state 302. This state 302
Indicates a state in which the slip control of the starting clutch 203 is being performed. Start clutch 20 in the present embodiment
Control 3 is performed in this state.

In the state in the state 302, if the value of the engine speed Ne becomes smaller than a predetermined threshold value Nth (a certain range in the first aspect), the engine speed Ne keeps a certain speed. State 3
Returning to 01, the starting clutch 203 is released. On the other hand, if the absolute value of the difference between the engine rotation speed Ne and the rotation speed Nin on the output side of the starting clutch 203 becomes smaller than the threshold value dth, the output of the starting clutch 203 is maintained in a state where the engine rotation speed Ne maintains a constant rotation speed. Since the torque on the side approaches the engine speed Ne, even if the starting clutch 203 is engaged, no engagement shock occurs, so that the state transits to the state 303 and the clutch is engaged. As described above, in the state 303, the clutch pressure is increased, and the starting clutch 203 is engaged. After the starting clutch 203 is engaged,
When the engine speed Ne becomes smaller than the threshold value Nth, the state transits to the state 301 and the clutch is released.

FIG. 4 is a flowchart showing the flow of processing according to the embodiment of the present invention.

In FIG. 4, in step 401, the target engine speed Ntg is determined based on the throttle opening TVO.
Calculate t. Next, at step 402, the current engine speed N is calculated from the engagement target engine speed Ntgt.
e is subtracted from the calculation, and the result is used to determine the difference rotational speed Ngap. In this step 402, the difference rotational speed Ngap
Is obtained, in step 403, the rotational speed Ng of the difference
The torque increment ΔT with respect to the clutch torque (the rotation speed of the drive wheel output shaft) with respect to the engine torque (engine rotation speed) is determined from the ap and the estimated running load. When the torque increment ΔT is obtained in step 403, the estimated engine torque Te is calculated from the throttle opening TVO and the engine speed Ne in step 404. In step 405, the estimated engine torque Te is added to the torque increment ΔT to obtain the clutch torque command. An operation for obtaining the value Tc is performed. Then, in step 406, the clutch torque command value Tc is converted into the clutch pressure command value Pc, and in step 407,
It outputs the clutch pressure Pc.

FIG. 5 is a timing chart showing values of various parts of the power system during clutch control according to the embodiment of the present invention.

The figure shows a state in which the accelerator pedal is depressed, the throttle opening TVO increases, and becomes constant at a certain value. At this time, the engine speed Ne
It rises from the idling rotation speed toward the engagement target rotation speed Ntgt, and becomes constant near the engagement target rotation speed Ntgt.

On the other hand, the rotation speed Nin on the output side (drive wheel output shaft) of the starting clutch 203 increases linearly because the starting clutch 203 is gradually engaged. Further, the output torque of the engine increases as the engine speed Ne increases and becomes constant at a certain value. At this time, the clutch pressure command value Pc that controls the slip control and the engagement control of the starting clutch 203 also becomes constant at the increased value. When the rotation speed Nin on the output side (drive wheel output shaft) of the start clutch 203 reaches a rotation speed within a predetermined range of the engine rotation speed Ne, the start clutch 203 is engaged.

When the starting clutch 203 is engaged,
At the same time, the engine speed Ne starts increasing again in the same manner as the vehicle speed increases. At this time, the value of the output torque To does not change before and after the start clutch 203 is engaged. The clutch pressure command value Pc sharply increases when the starting clutch 203 is engaged.

FIG. 6 is a graph showing the relationship between the throttle opening TVO and the target engagement speed Ntgt.

In the figure, in the region where the throttle opening TVO is small, the engine torque is small and the engine speed N
Since e does not easily increase, the target engagement speed Ntgt is low. Conversely, where the throttle opening TVO is large, the target engagement speed Ntgt is high.

FIG. 7 shows the relationship between the rotational speed Ngap, which is the difference between the target engagement rotational speed Ntgt and the engine rotational speed Ne, and the increase ΔT of the clutch torque with respect to the engine torque. In the figure, when the traveling load is small, the engine speed Ne is lower than the engagement target speed Ntgt in a region where the difference speed Ngap is positive, and therefore the engine speed N
e must be raised. This engine speed N
In order to increase e, it is necessary to make the clutch torque smaller than the engine torque. Therefore,
The clutch torque increment ΔT is negative.

Conversely, in the region where the difference rotational speed Ngap is negative, the clutch torque increment ΔT must be positive. The graph of the increase ΔT of the clutch torque has a steep slope near the difference rotation speed Ngap of 0 in FIG.
Does not change much in the region where the absolute value of is large. On the other hand, when the running load increases, the clutch torque needs to be increased. Therefore, the clutch torque increment ΔT is increased in a region where the difference rotational speed Ngap is positive. Further, in order to generate a large engine torque, it is necessary to increase the engine speed Ne, and the clutch torque increment Δ
T becomes 0, and the rotational speed Ngap of the difference is made negative.

FIG. 8 is a graph showing the torque characteristics of the engine.

In the drawing, each curve represents a throttle opening T
It is a characteristic curve of the engine torque Te with respect to the engine speed Ne when VO is kept constant. The throttle opening TVO is small at the lower left of the graph, and the throttle opening TVO increases toward the upper right.

FIG. 9 is a block diagram of the running load estimating means.

In the figure, the acceleration is indicated by a block 1001.
Is multiplied by the vehicle weight and input to the subtraction means 1003. The clutch torque command value is multiplied by the gear ratio in block 1002, divided by the tire radius, and input to the subtraction means 1003. In the subtraction means 1003, the output of the block 1001 is subtracted from the output of the block 1002, and the estimated running load is output.

FIG. 10 is a flowchart showing the flow of processing of the traveling load estimating means 108 when the vehicle starts on a slope.

In the figure, in step 1101,
The acceleration is multiplied by the vehicle weight, and in step 1102,
The clutch torque command value is multiplied by the gear ratio, and a calculation process of dividing by the tire radius is performed. When the arithmetic processing is performed in step 1102, in step 1103,
An estimated running load is obtained by subtracting the calculation result of step 1101 from the calculation result of step 1102. This estimated running load is output to the clutch torque increment calculating means 103, and the clutch torque increment ΔT applied when the starting clutch is engaged is calculated.

By using the value obtained by multiplying the acceleration by the vehicle weight in the calculation of the estimated running load, a change in the load due to the vehicle weight such as a slope is added, and the starting clutch 203 can be smoothly engaged on the slope. Becomes

[0040]

According to the present invention, the clutch pressure control device at the time of starting can perform clutch pressure control without shock without a sudden change in output torque when the clutch is slipping or engaging.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a signal flow and processing according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a power system (power train) of an automobile to which the present invention is applied.

FIG. 3 is a state transition diagram of clutch control at the start of an automobile to which the embodiment of the present invention is applied.

FIG. 4 is a flowchart illustrating a flow of a process according to the embodiment of the present invention.

FIG. 5 is a timing chart showing values of various parts of the power system during clutch control according to the embodiment of the present invention.

FIG. 6 shows the throttle opening TVO and the target engagement speed Ntg.
6 is a graph showing the relationship of t.

FIG. 7 shows a target engagement speed Ntgt and an engine speed Ne.
FIG. 9 is a graph showing a relationship between a difference Ngap of the clutch torque, an engine torque, and an increase ΔT of a clutch torque with respect to an estimated traveling load.

FIG. 8 is a graph showing torque characteristics of an engine.

FIG. 9 is a block diagram of running load estimating means.

FIG. 10 is a block diagram showing a processing flow of a traveling load estimating means.

[Explanation of symbols]

 101 engagement target engine speed calculation means 102 addition means 103 addition means 103 clutch torque increase calculation means 104 engine torque estimation means 105 engine torque estimation means 105 Addition means 106 Clutch pressure conversion means 107 Differentiation means 108 Running load estimation means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuya Ochi 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Takashi Okada 7-1 Omikamachi, Hitachi City, Ibaraki Prefecture No. 1 Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Mitsuo Kayano 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratory Hitachi, Ltd. F term (reference) 3J057 AA03 BB03 GA23 GA30 GA49 GA66 GB02 GB04 GB10 GB14 GB19 GB22 GB32 GB36 GD26 GE05 GE07 HH02 JJ01

Claims (2)

[Claims] An apparatus for controlling the start of a start clutch for transmitting an engine driving force from an engine output shaft to a transmission, the engine controlling a constant engine speed determined by a throttle opening degree set by a driver at the start. The engagement of the starting clutch is controlled such that the rotation speed of the drive wheel output shaft connected to the starting clutch is equal to the target engine rotation speed of the clutch engagement determined by the throttle opening while maintaining the range of A clutch control device, characterized in that: 2. A device for controlling the start of a start clutch for transmitting engine driving force from an engine output shaft to a transmission, the start clutch controlling means for controlling engagement and disengagement of the start clutch. Target engine speed detecting means for detecting a target engine speed for clutch engagement determined by the set throttle opening; an engine speed sensor for detecting a speed of the engine output shaft; and a drive connected to the starting clutch. An output shaft rotation sensor for detecting the rotation speed of the wheel output shaft, and a drive detected by the engine rotation speed and the output shaft rotation sensor that rotate at the engine rotation speed determined by the throttle opening detected by the engine rotation speed sensor. The engine rotational speed detected by the engine rotational speed sensor is determined in advance by comparing the rotational speed with the wheel output shaft rotational speed. The starting clutch control means performs start clutch disconnection control so as to maintain the rotation speed within a certain range, and transmits driving force to the drive wheel output shaft. A clutch control device comprising: starting clutch engagement control means for engaging the starting clutch when a target engine speed for clutch engagement detected by target engine speed detecting means is reached.