JPH0579552A - Starting clutch controller for automatic transmission - Google Patents

Abstract

PURPOSE:To suppress difference in a turbine torque of a fluid joint at the time of starting, and to constantly ensure stable starting function in a starting clutch controller of an automatic transmission for controlling the fastening force of a starting clutch of an auxiliary speed gear at the time of starting of a vehicle. CONSTITUTION:A turbine torque when it is assumed that a starting clutch (e) is completely fastened, is estimated based on the engine rotational number and the output shaft rotational number of a transmission, at the time of starting, and while the estimated turbine torque is determined as an aimed turbine torque, a starting clutch fastening force control means (g) for carrying out the fastening force control of the starting clutch (e) so that an actual turbine torque is obtained which becomes gradually close to the aimed turbine torque, is also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting clutch control device for an automatic transmission, which controls the engaging force of a starting clutch of an auxiliary transmission when the vehicle starts.

[0002]

2. Description of the Related Art Conventionally, as a starting clutch control device for an automatic transmission, for example, one disclosed in Japanese Patent Laid-Open No. 61-249839 is known.

In the above-mentioned conventional sources, the clutch engagement force is increased according to the integrated value of the engine output equivalent signal such as the engine speed and the throttle opening at the time of starting, so that there is no delay or premature in the engagement timing of the starting clutch. Thus, a technique for optimal control is shown.

[0004]

However, in the above-mentioned conventional starting clutch control device for an automatic transmission, the engine state is included in the control information, but the state of the torque converter is not included in the control information. The turbine torque of the torque converter varies due to the difference in the load of the auxiliary transmission at the time of starting, and there is a problem that stable starting performance cannot always be ensured.

Further, even when the starting clutch control in which the state of the torque converter is included in the control information is not taken into consideration, when the rate of change of the turbine rotational speed is not taken into consideration, when the turbine rotational speed drops with a large rate of change immediately before the starting clutch is completely engaged, Torque is generated due to the inertia of the turbine, which causes a rapid increase in output shaft torque, resulting in a start shock.

The present invention has been made in view of the above problems, and in a starting clutch control device for an automatic transmission for controlling the engaging force of a starting clutch of an auxiliary transmission at the time of starting the vehicle, a fluid coupling at the time of starting The first problem is to suppress the turbine torque variation and secure stable starting performance at all times.

In addition to the above first problem, a second problem is to prevent the occurrence of a starting shock due to a sudden increase in the output shaft torque when the turbine rotational speed changes greatly immediately before the starting clutch is completely engaged. ..

In addition to the first or second problem described above, a third problem is to prevent clutch burnout when the start clutch is slip-engaged for a long time.

[0009]

In order to solve the above-mentioned first problem, in the starting clutch control system for an automatic transmission according to the present invention, the starting clutch is completely set based on the engine speed and the transmission output shaft speed at the time of starting. The torque of the starting clutch is predicted so that the actual turbine torque that asymptotically approaches the target turbine torque is obtained by using the predicted turbine torque as the target turbine torque. did.

That is, as shown in the claim correspondence diagram of FIG. 1, a fluid coupling d which is connected to the engine a and has a pump impeller b and a turbine runner c, is provided at a position downstream of the fluid coupling d, and is fastened at the time of starting. An auxiliary transmission f having a starting clutch e, a starting clutch engaging force control means g for controlling the engaging force of the starting clutch e, a starting operation detecting means h for detecting a starting operation, and a predetermined state quantity. Torque ratio setting means i for determining the ratio of the target turbine torque to the predicted turbine torque, and the fluid coupling d on the assumption that the starting clutch e is completely engaged.
Predicting turbine torque of the turbine torque of the engine from the engine speed and the transmission output shaft speed,
When a starting operation is detected, a target starting clutch torque calculating means k for calculating a target starting clutch torque from the predicted turbine torque and a torque ratio, and the starting clutch engaging force control means g for obtaining the target starting clutch torque. Command output means m for outputting a fastening force control command to
It has and.

In order to solve the above second problem, in the starting clutch control system for an automatic transmission according to the present invention, the proportional coefficient is set to a lower value as the turbine rotation speed change rate is lower, and is proportional to the torque ratio up to the previous time. The turbine rotation speed integrated value obtained by adding a value obtained by multiplying the turbine rotation speed of this time with the above is used as a means for setting the torque ratio.

That is, as shown in the claim correspondence diagram of FIG. 1, in the starting clutch control device for an automatic transmission according to claim 1, turbine speed change rate calculation means p for calculating the change rate of turbine speed, Proportion coefficient determining means q for determining the proportional coefficient of the turbine rotation speed to be added for each control cycle to a lower value as the turbine rotation speed change rate is lower is provided, and the torque ratio setting means i is proportional to the torque ratio up to the previous time. A means for setting the turbine rotation speed integrated value obtained by adding the value obtained by multiplying the coefficient by the turbine rotation speed this time as the torque ratio.

In order to solve the third problem described above, in the starting clutch control device for an automatic transmission according to the present invention, control is performed when the amount of heat generated by the starting clutch in the slip-engaged state from the start of the starting clutch control exceeds the heat resistance limit region. Was used as a means for completely stopping the starting clutch.

That is, as shown in the claim correspondence diagram of FIG. 1, in the starting clutch control device for an automatic transmission according to claim 1 or 2, the problem occurs in the starting clutch e in the slip-engaged state from the start of the starting clutch control. The clutch heat generation amount calculation means n for calculating the heat generation amount with the passage of time, and when the clutch heat generation amount by the clutch heat generation amount calculation means n exceeds the heat resistance limit region, the start clutch control is stopped and the start clutch e is completely engaged. Starting clutch control ending means o for outputting a command is provided.

[0015]

The operation of the present invention will be described.

When the starting operation detecting means h detects the starting operation at the time of starting, the target starting clutch torque calculating means k
At, the target starting clutch torque is calculated from the predicted turbine torque and the torque ratio. Where fluid coupling d
The predicted turbine torque of is predicted by the predicted turbine torque calculation means j from the engine speed and the transmission output shaft speed as torque assuming that the starting clutch e is completely engaged. In the torque ratio setting means i, the ratio of the target turbine torque to the predicted turbine torque is set according to the predetermined state quantity.

Then, in the control command output means m, an engaging force control command is issued to the starting clutch engaging force control means g for controlling the engaging force of the starting clutch e which is engaged at the time of starting so that the target starting clutch torque is obtained. Is output.

Therefore, at the time of starting, the turbine torque when the starting clutch e is assumed to be completely engaged is predicted based on the engine speed and the transmission output shaft speed, and this predicted turbine torque is used as the target turbine torque. As a result, by controlling the engagement force of the starting clutch e so that an actual turbine torque that gradually approaches the target turbine torque is obtained, variations in the turbine torque of the fluid coupling at the time of starting are suppressed, and stable starting performance is always ensured. It will be.

The operation of the invention according to claim 2 will be described.

In controlling the engagement force of the starting clutch e, the proportional coefficient of the turbine speed added by the proportional coefficient determining means q for each control cycle is the turbine speed changing rate from the turbine speed changing rate calculating means p. Is determined to be a lower value, and in the torque ratio setting means i,
The integrated value of the turbine rotation speed obtained by adding the value obtained by multiplying the torque proportion up to the previous time by the proportional coefficient and the turbine rotation speed of this time is set as the torque proportion.

Therefore, at the time of starting, the starting clutch e
When the turbine rotation speed change rate is high in the region where the fastening force increases from the start of fastening, the proportional coefficient is set to a high value,
Control is performed to increase the torque ratio increasing gradient based on this proportional coefficient to increase the engaging force of the starting clutch e. Then, when the turbine speed decreases with a large rate of change immediately before the complete engagement of the starting clutch, the proportional coefficient is set to a low value, and the increasing gradient of the torque ratio is reduced to control the engaging force of the starting clutch e. Become. As a result, the increase in the output shaft torque is moderated, and even if the torque generated by the inertia of the turbine is added to the output shaft torque, the rapid increase in the output shaft torque can be suppressed.

The operation of the invention according to claim 3 will be described.

When the start clutch control is started, the clutch heat generation amount calculation means n calculates the heat generation amount generated in the start clutch e in the slip-engaged state from the start of the control over time. Then, when the clutch heat generation amount by the clutch heat generation amount calculation means n exceeds the heat resistance limit region, the start clutch control ending means o stops the start clutch control and outputs a complete engagement command to the start clutch e.

Therefore, when the starting clutch e is slip-engaged for a long time in the starting clutch control, the control is forcibly ended before the original condition for ending the clutch control is satisfied. It is possible to prevent burnout of e.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the structure will be described.

FIG. 2 is a block diagram of a control system showing a starting clutch control device for an automatic transmission according to a first embodiment of the invention described in claim 1. FIG. 3 is an automatic gear shift to which the device according to the first embodiment is applied. FIG. 4 is a schematic view showing a power train of the machine, and FIG. 4 is a view showing a fastening operation table of the automatic transmission to which the first embodiment device is applied.

As shown in FIG. 3, the power train of the automatic transmission to which the device of the first embodiment is applied has a torque converter 1 (corresponding to a fluid coupling), an oil pump 2, an input shaft 3, a band brake 4, a river. Scratch 5,
High clutch 6, front sun gear 7, front pinion 8, front ring gear 9, front planet carrier 10, rear sun gear 11, rear pinion 12, rear ring gear 13, rear planet carrier 14, forward clutch 15 (equivalent to start clutch), forward one way Clutch 16, overrun clutch 17,
A low one-way clutch 18, a low & reverse brake 19, a parking pole 20, a parking gear 21, and an output shaft 22 are provided.

The torque converter 1 includes a pump impeller 1a connected to an engine crankshaft (not shown).
And a turbine runner 1b connected to the input shaft 3 and a stator 1e provided in the case 1c via a one-way clutch 1d, and a lock-up clutch 1f is built therein.

A front planetary gear set and a rear planetary gear set, which are provided between the input shaft 3 and the output shaft 22, and a gear shifting element such as a clutch and a brake are engaged as shown in FIG. , An auxiliary transmission having shift positions of reverse range, neutral range, drive range (4th speed), 2nd fixed range, and 1st fixed range.

As shown in FIG. 2, the starting clutch control apparatus of the first embodiment uses, as control hardware, a forward clutch 15 as a starting clutch and a clutch oil passage 30 for supplying an engagement pressure to the forward clutch 15. A hydraulic control valve 31 (corresponding to a starting clutch engaging force control means), an A / T control unit 32 for outputting a predetermined duty control command to the hydraulic control valve 31, and the A / T control unit 32.
/ T control unit 32 which provides input information to accelerator opening sensor 33, engine speed sensor 34, turbine speed sensor 35, output shaft speed sensor 36, AT
And an F oil temperature sensor 37.

Next, the operation will be described.

(A) Start clutch control operation FIG. 5 is a flow chart showing the flow of the start clutch control operation performed by the A / T control unit 32, and each step will be described below.

In step 50, the sensors 33, 34,
The accelerator opening θ, the engine speed Ne, the turbine speed Nt, the output shaft speed No (corresponding to the transmission output shaft speed), and the ATF oil temperature TA are measured by 35, 36, and 37.

In step 51, it is judged whether or not the vehicle is in the starting operation depending on whether the accelerator opening θ is zero (corresponding to the starting operation detecting means). Then, when θ = 0, this control is not performed, and only when θ ≠ 0, the control proceeds to the starting clutch control after step 52.

At step 52, the absolute value of the difference between the turbine speed Nt and the output shaft speed No multiplied by the gear ratio i ₁ of the first speed is less than 10 (this is a number considering the measurement error). It is determined whether the forward clutch 15 is slipping or not.

That is, when | Nt-i ₁ · No | ≦ 10 is satisfied, the forward clutch 15 is in the completely engaged state without slip, and the condition for ending the clutch slip engagement control is satisfied. In step 53, the maximum clutch engagement pressure Pmax is set as the clutch engagement pressure P.
Is output.

On the other hand, when | Nt-i ₁ · No |> 10,
When it is determined that the forward clutch 15 is slipping, in steps 54 to 57, the predicted turbine torque T is calculated according to the integrated value ΣNt of the turbine rotation speed Nt.
The ratio δ of the target starting clutch torque T _{FWD to} t is determined (corresponding to torque ratio setting means).

In step 54, the turbine rotation speed Nt from the start of control is integrated to obtain a turbine rotation speed integrated value ΣNt.
Is required.

In step 55, it is determined whether the turbine rotation speed integrated value ΣNt is less than the predetermined value Nmax. Then, when Nmax> ΣNt, the routine proceeds to step 56, where the ratio δ is calculated from the predetermined minimum value δ ₁ and maximum value δ ₂ by the following equation.

Δ = (ΣNt / Nmax) (δ ₂ −δ ₁ ) + δ _{1 When} Nmax ≦ ΣNt, the process proceeds to step 57.
In step 57, the ratio δ is set to the maximum value δ ₂ .

That is, the ratio δ set in steps 54 to 57 is the minimum value δ ₁ when the turbine rotation speed integrated value ΣNt is zero, as shown in the upper part of FIG.
Then, as the turbine rotation speed integrated value ΣNt increases, the value gradually increases, and the turbine rotation speed integrated value ΣNt becomes the predetermined value N.
When max is reached, the maximum value is set to δ ₂ .

In step 58, the forward clutch 1
The predicted turbine torque Tt of the torque converter 1 when it is assumed that No. 5 is completely engaged is predicted by the following formula from the engine speed Ne and the output shaft speed No based on the torque converter characteristics (prediction). Equivalent to turbine torque calculation means).

E = No / Ne e; speed ratio τ = τ (e) τ; torque capacity coefficient t = t (e) t; torque ratio Te = τ × Ne ² Te; engine torque Tt = t × Te Step 59 Then, the target forward clutch torque T _FWD (target starting clutch torque) is calculated by the following formula from the predicted turbine torque Tt, the torque ratio δ, and the gear ratio α ₂ of the rear planetary gear set (target starting clutch torque calculating means). Equivalent to).

T _FWD = (1 / α ₂ ) δδTt In step 60, the clutch hydraulic pressure P is obtained from the target forward clutch torque T _FWD and the ATF oil temperature TA, and the engagement pressure control for obtaining this clutch hydraulic pressure P is obtained. A command is output to the hydraulic control valve 31 (corresponding to control command output means).

(B) Starting action At the time of starting by the above control operation, the A / T control unit 32 causes the engine and the torque converter 1 to operate.
Irrespective of the state, as shown in the lower part of FIG. 6, the predicted turbine torque T that is always the target turbine torque.
The engagement pressure of the forward clutch 15 is controlled so that the actual turbine torque asymptotic to t can be obtained.

In this way, controlling the turbine torque so that a constant relationship is always obtained by controlling the engagement pressure of the forward clutch 15 eliminates the influence of changes in the starting performance due to variations in the turbine torque of the torque converter 1. become.

Because the turbine torque is generated by being influenced by the state of the engine arranged at the upstream position and the state of the torque converter 1, if the turbine torque generated after passing through these is controlled, And the influence of the change in the state of the torque converter 1 is automatically eliminated.

As described above, the starting clutch control device for the automatic transmission according to the first embodiment exhibits the effects listed below.

(1) The engine speed Ne, the turbine speed Nt, and the output shaft speed No are included in the input information, and the forward is performed so that the actual turbine torque asymptotically approaching the predicted turbine torque Tt which is the target turbine torque at the time of starting is obtained. Since the device for controlling the engagement pressure of the clutch 15 is used, variations in turbine torque of the torque converter 1 at the time of starting can be suppressed, and stable starting performance can always be ensured.

(2) In controlling the engagement pressure of the forward clutch 15 so that the actual turbine torque asymptotic to the predicted turbine torque Tt is obtained, the ratio δ is set with the turbine rotation speed integrated value ΣNt as the state quantity. Therefore, variations in the turbine rotation speed of the torque converter 1 are suppressed at the time of starting, and stable starting performance can be always ensured.

That is, when the turbine rotation speed Nt is high, the engagement gain of the forward clutch 15 is increased to promote the reduction of the turbine rotation speed, and when the turbine rotation speed Nt is low, the engagement gain of the forward clutch 15 is increased. For example, unlike the case where time is used as the state quantity, the turbine rotation speed Nt is controlled so that the turbine rotation speed Nt becomes a constant rotation speed when the vehicle starts, such that the decrease in the turbine rotation speed is suppressed by lowering the.

(Second Embodiment) Next, a starting clutch control system for an automatic transmission according to a second embodiment of the present invention will be described.

In the second embodiment apparatus, the starting clutch control of the first embodiment apparatus does not consider the rate of change of the turbine speed, whereas the starting clutch control takes into consideration the rate of change of the turbine speed. This is an example of performing.

Since the configuration is the same as that of the first embodiment device, illustration and description thereof will be omitted.

Next, the operation will be described.

(A) Start clutch control operation FIG. 7 is a flowchart showing the flow of the start clutch control operation performed by the A / T control unit 32, and each step will be described below.

Incidentally, step 56 in the flowchart of FIG.
Are replaced by steps 61 and 62, and steps 50 to 6 except step 56 are replaced.
Since 0 is a processing step similar to that in the flowchart of FIG. 5, description of these steps will be omitted.

In step 61, when it is determined in step 55 that the turbine rotation speed integrated value ΣNt is less than the predetermined value Nmax, the torque ratio increase rate G (corresponding to the proportional coefficient) is determined according to the torque ratio increase rate determination process described later. It is determined.

In step 62, the previous torque ratio δ (k
-1), the current turbine speed Nt (k), and the torque ratio increase rate G, the current torque ratio δ (k) is calculated by the following formula (corresponding to the torque ratio setting means in claim 2). ..

Δ (k) = δ (k-1) + GNt (k) FIG. 8 is a flow chart showing the flow of the specific torque ratio increase rate determination processing operation in step 61. Each step will be described.

In step 61a, the turbine rotational speed change rate ΔNt (k) is calculated from the difference between the present turbine rotational speed Nt (k) and the previous turbine rotational speed Nt (k-1) (turbine rotational speed change rate). Equivalent to computing means).

In step 61b, it is determined whether the turbine rotation speed change rate ΔNt (k) is ΔNt (k) <0.

In step 61c, the increase rate flag F _G
However, it is determined whether F _G = 1.

In step 61d, the torque ratio increase rate G
Is set to G = G ₁ .

In step 61e, the increase rate flag F _G, which is set to the initial value 0, is set to F _G = 1.

In step 61f, the torque ratio increase rate G
Is set to G = G ₂ (G ₁ > G ₂ ). The steps 61b to 61f correspond to the proportional coefficient determining means.

(B) Starting action For example, in the case of performing the starting clutch control for keeping the increasing gradient of the torque ratio δ constant, the forward clutch 15 is completely engaged as shown in the turbine speed characteristic of (a) of FIG. Even immediately before the turbine speed Nt decreases with a large rate of change, the clutch engaging force increases in accordance with the torque ratio δ. Therefore, the increase in the output shaft torque due to the increase in the clutch engagement force is accompanied by the inertia torque of the turbine due to the sudden decrease in the turbine rotational speed, and as shown in the output shaft torque characteristic of FIG. Has caused a rapid increase in
As a result, a starting shock is generated.

On the other hand, in the case of the starting clutch control of the second embodiment, the forward clutch 1
When the turbine rotation speed change rate ΔNt (k) is ΔNt (k) ≧ 0 in the region where the fastening force increases from the start of fastening of No. 5, when
At step 61a, step 61b, step 61c, and step 61d, the increase rate G
Is set to a high value G ₁ , the increasing gradient of the torque ratio δ (k) becomes large, and the engaging force of the forward clutch 15 is set so that the actual turbine torque asymptotic to the target turbine torque is obtained as in the first embodiment. Control is performed to increase.

Immediately before the forward clutch 15 is completely engaged, the turbine speed Nt decreases and the turbine speed change rate ΔNt (k) becomes ΔNt (k) <0. In FIG. 8, step 61a → step 61b. → Step 6
1e → the flow proceeds to step 61f, the increase rate G is set to a low value G _2, and thereafter, even if ΔNt (k) ≧ 0, the process proceeds to step 61c → step 61f and the increase rate G ₂ is held. As shown in (B) torque ratio characteristic of No. 9, control is performed to increase the engagement force of the forward clutch 15 by decreasing the increasing gradient of the torque ratio δ (k).

As a result, the increase in the output shaft torque due to the engagement of the clutch is moderated, and even if the torque generated by the inertia of the turbine due to the rapid decrease in the turbine speed Nt is added to the output shaft torque, the curve shown in FIG. As shown in the output shaft torque characteristic of), the rapid increase of the output shaft torque To is suppressed. As a result, starting shock is prevented.

As described above, in the starting clutch control system for the automatic transmission of the second embodiment, the following effects are added to the effects of the first embodiment system.

(3) When the rate of change in turbine speed ΔNt (k) is ΔNt (k) <0, the increase rate G is set to a low value G ₂ .
Since the device for performing the control for increasing the engagement force of the forward clutch 15 by decreasing the increasing gradient of the torque ratio δ (k), when the turbine speed Nt decreases immediately before the complete engagement of the forward clutch 15, Output shaft torque To
It is possible to prevent the occurrence of a starting shock due to a rapid increase in the vehicle.

Now, another mode of the operation of the torque ratio increase rate determination processing in step 61 will be described with reference to FIGS. 10 and 11.

In the flowchart of FIG. 10, step 6
At 1 g, it is judged whether or not ΔNt (k) −5000 (rad / s ² ) <0, and at step 61h, ΔNt (k−1) −5000 (rad / s ² ) ≧ 0.
It is determined whether or not. That is, ΔN in the current control cycle
t (k) <5000 is satisfied, and ΔNt is set in the previous control cycle.
This is an example in which the increase rate G is rewritten from G ₁ to G ₂ when (k−1) ≧ 5000 is satisfied, and then G ₂ is held. In this example, the time for rewriting the increase rate G from G ₁ to G ₂ is earlier than in the case of FIG.

In the flow chart of FIG. 11, step 61
The rate of increase G at i is G = k · ΔNt (k) + Gb (k;
Proportional constant, Gb; initial value at the start of starting). That is, the increase rate G is the turbine rotation speed change rate ΔN.
It is rewritten steplessly according to t (k).

(Third Embodiment) Next, a starting clutch control system for an automatic transmission according to a third embodiment of the present invention will be described.

In this third embodiment device, the starting condition of the starting clutch control of the first and second embodiment devices is as shown in FIGS.
As shown in step 52 of FIG.
However, the amount of heat generation Q of the forward clutch 15 is kept even when the forward clutch 15 is in a slipping state for the purpose of preventing clutch burnout when the slip engagement time is long. This is an example in which the starting clutch control is terminated when the heat resistance limit Qlim is reached, and the four modes are shown below. The starting clutch control itself is the same as in the case of the first and second embodiment devices (FIGS. 5 and 7), and thus the description thereof is omitted.

FIG. 12A is a flow chart showing the flow of the ending process operation of the starting clutch control of the first mode.
2 (b) is the time chart.

In step 70, the turbine speed Nt,
Output shaft speed No. and ATF oil temperature TA are measured.

At step 71, the slip speed ω is calculated from the turbine speed Nt and the output shaft speed No.

[0082] At step 72, the loss work rate P _loss in the forward clutch 15 is multiplied by the engagement capacity command value Tc to the sliding velocity ω and the forward clutch 15 is calculated.

In step 73, this loss power is integrated from the start of the starting operation, and this is multiplied by the sampling period to to calculate the heat generation amount Q in the forward clutch 15 (corresponding to clutch heat generation amount calculation means). ..

In step 74, it is judged whether or not the heat generation amount Q exceeds the heat resistance limit Qlim.

When Q> Qlim is satisfied, a command for completely engaging the forward clutch 15 is output in step 75, and a command for stopping the starting clutch control is output in step 76 (in the starting clutch control ending means). Equivalent).

Therefore, the slip speed from the start control start when the heat generation amount Q of the forward clutch 15 reaches the heat resistance limit Qlim before the slippage of the forward clutch 15 is eliminated,
The characteristics of the heat generation amount and the engagement force are as shown in (B) of FIG. 12, and clutch burnout of the forward clutch 15 is prevented.

FIG. 13A is a flow chart showing the flow of the ending process operation of the starting clutch control of the second mode.
(B) of 3 is the time chart.

Steps 80 to 83 correspond to steps 70 to 73.

At step 84, it is judged if this heat generation amount Q exceeds 90% of the heat resistance limit Qlim.

When Q> 0.9 · Qlim is satisfied, a command to stop the starting clutch control is output in step 85, and a command to gradually increase the engaging force of the forward clutch 15 is output in step 86.

Therefore, when the heat generation amount Q of the forward clutch 15 exceeds 90% of the heat resistance limit Qlim before the slippage of the forward clutch 15, the characteristics of the slip speed, the heat generation amount, and the engaging force from the start control start are as follows. As shown in FIG. 13 (B), not only the clutch burnout of the forward clutch 15 is prevented, but also the shock due to the sudden engagement of the forward clutch 15 is prevented.

FIG. 14A is a flow chart showing the flow of the ending processing operation of the starting clutch control of the third mode.
(B) of 4 is the time chart.

Steps 90 to 96 correspond to steps 80 to 86.

At step 97, the ignition timing of the engine is delayed by a predetermined time from the time when the heat generation amount Q exceeds 90% of the heat resistance limit Qlim, and at step 98, the ignition timing is restored.

Therefore, when the heat generation amount Q of the forward clutch 15 exceeds 90% of the heat resistance limit Qlim before the slippage of the forward clutch 15, the slip speed, the heat generation amount, the engaging force, and the ignition timing from the start control start. Each characteristic is as shown in (b) of FIG. 14, and the clutch burnout of the forward clutch 15 is prevented, the shock is prevented from being generated by suddenly engaging the forward clutch 15, and the transmission is performed by a temporary ignition timing retard. By reducing the torque, the progress of heat generation in the forward clutch 15 is suppressed.

FIG. 15A is a flow chart showing the flow of the ending processing operation of the starting clutch control of the fourth mode.
(B) of 5 is the time chart.

Steps 100 to 106 correspond to steps 90 to 96. In step 107, the fuel supply to the predetermined cylinder of the engine is cut off for a predetermined time from the time when the heat generation amount Q exceeds 90% of the heat resistance limit Qlim, and in step 108, the fuel supply is restored.

Therefore, when the calorific value Q of the forward clutch 15 exceeds 90% of the heat resistance limit Qlim before the slip of the forward clutch 15 disappears, the slip speed, the calorific value, the fastening force, and the fuel supply amount from the start control start. Each characteristic of
As shown in (b) of FIG. 7, the clutch burnout of the forward clutch 15 is prevented, the shock is prevented from being generated by suddenly engaging the forward clutch 15, and the transmission torque is reduced by temporarily stopping the fuel supply. The progress of heat generation in the forward clutch 15 is suppressed.

Although the embodiment has been described with reference to the drawings, the specific configuration and control contents are not limited to the embodiment.

For example, as long as it has a clutch corresponding to the starting clutch, it goes without saying that it can be applied to automatic transmissions other than those shown in the embodiments.

In the embodiment, a torque converter is used as the fluid coupling, but a fluid coupling may be used.

[0102]

According to the present invention as set forth in claim 1, in a starting clutch control device for an automatic transmission for controlling a fastening force of a starting clutch of an auxiliary transmission at the time of starting the vehicle, an engine speed and a gear change are performed at the time of starting. Predict the turbine torque when it is assumed that the starting clutch is completely engaged based on the machine output shaft speed, and use this predicted turbine torque as the target turbine torque to obtain the actual turbine torque that is asymptotic to this target turbine torque. Since the means for controlling the engaging force of the starting clutch is used as described above, it is possible to obtain an effect that it is possible to suppress variation in turbine torque of the fluid coupling at the time of starting and always ensure stable starting performance.

According to the second aspect of the present invention, the proportional coefficient is set to a lower value as the turbine rotation speed change rate is lower,
In addition to the above effect, immediately before the complete engagement of the starting clutch In the case where the turbine rotational speed changes greatly, it is possible to obtain the effect that it is possible to prevent the occurrence of a starting shock due to a sudden increase in the output shaft torque.

According to the third aspect of the present invention, the means for stopping the control and completely engaging the starting clutch when the amount of heat generated by the starting clutch in the slip-engaged state from the start of the starting clutch control exceeds the heat resistance limit region. Therefore, in addition to the effect described in claim 1 or claim 2, there is an effect that it is possible to prevent clutch burnout when the start clutch is slip-engaged for a long time.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a starting clutch control device for an automatic transmission according to the present invention.

FIG. 2 is a block diagram of a control system showing a starting clutch control device for an automatic transmission according to a first embodiment.

FIG. 3 is a schematic diagram showing a power train of an automatic transmission to which the starting clutch control device of the first embodiment is applied.

FIG. 4 is a view showing a fastening operation table of an automatic transmission to which the starting clutch control device of the first embodiment is applied.

FIG. 5 is a flowchart showing a flow of a starting clutch control processing operation performed by the A / T control unit of the first embodiment.

FIG. 6 is a characteristic diagram of a torque ratio, a predicted turbine torque, and a target forward clutch torque when the turbine rotation speed integrated value is plotted on the horizontal axis in the first embodiment device.

FIG. 7 is a flowchart showing a flow of a starting clutch control processing operation performed by the A / T control unit of the second embodiment.

FIG. 8 is a flowchart showing a flow of a torque ratio increase rate determination processing operation of the first example.

FIG. 9A is a start time chart when a constant torque ratio is used, and FIG. 9B is a start time chart in the second embodiment device.

FIG. 10 is a flowchart showing a flow of a torque ratio increase rate determination processing operation of a second example.

FIG. 11 is a flowchart showing a flow of a torque ratio increase rate determination processing operation of a third example.

FIG. 12A is a flow chart showing a flow of an ending process operation of the starting clutch control of the first mode.
(B) is the time chart.

FIG. 13A is a flowchart showing the flow of the ending processing operation of the starting clutch control of the second mode.
(B) is the time chart.

FIG. 14A is a flowchart showing a flow of an ending process operation of the starting clutch control of the third mode.
(B) is the time chart.

FIG. 15 (a) is a flowchart showing a flow of an ending process operation of the starting clutch control of the fourth mode.
(B) is the time chart.

[Explanation of symbols]

 a engine b pump impeller c turbine runner d fluid coupling e starting clutch f auxiliary transmission g starting clutch engaging force control means h starting operation detecting means i torque ratio setting means j predicted turbine torque calculating means k target starting clutch torque calculating means m control Command output means n Clutch heat generation amount calculation means o Start clutch control termination means p Turbine speed change rate calculation means q Proportional coefficient determination means

Claims (3)

[Claims] 1. A fluid coupling that is connected to an engine and that includes a pump impeller and a turbine runner; an auxiliary transmission that is provided at a position downstream of the fluid coupling and that has a starting clutch that is engaged at the time of starting; and engagement of the starting clutch. A starting clutch engagement force control means for controlling the force, a starting operation detecting means for detecting a starting operation, a torque ratio setting means for determining a ratio of the target turbine torque to the predicted turbine torque according to a predetermined state quantity, and the starting clutch Is predicted, the turbine torque of the fluid coupling when it is assumed to be completely engaged is predicted from the engine speed and the transmission output shaft speed, and when the start operation is detected, the predicted turbine torque is calculated. Target starting clutch torque calculating means for calculating a target starting clutch torque from the torque and the torque ratio; Starting clutch control device for an automatic transmission, characterized by comprising a control command output means for outputting the engagement force control command to said starting clutch engagement force control means as target start clutch torque is obtained. 2. The starting clutch control device for an automatic transmission according to claim 1, wherein a turbine rotation speed change rate calculating means for calculating a change rate of the turbine rotation speed, and a proportional coefficient of the turbine rotation speed to be added for each control cycle. Is provided with a proportional coefficient determining means for determining a lower value as the rate of change in turbine speed is lower, and the torque ratio setting means adds a value obtained by multiplying the torque ratio up to the previous time by the proportional coefficient and the turbine speed this time. A starting clutch control device for an automatic transmission, characterized in that the integrated turbine rotation speed integrated value is set as a torque ratio. 3. The starting clutch control device for an automatic transmission according to claim 1, wherein the amount of heat generated by the starting clutch in the slip-engaged state from the start of the starting clutch control is calculated over time. And a starting clutch control ending means for stopping the starting clutch control and outputting a complete engagement command to the starting clutch when the clutch heating value calculated by the clutch heating value calculating means exceeds the heat resistance limit region. A starting clutch control device for an automatic transmission characterized by the above.