JPH05164241A - Slip control device of direct coupling clutch for vehicle - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a shock and a jolt, even when fuel cut control is executed during travel at a reduced speed by sequentially permitting slip control for a direct coupling clutch and the fuel cut control, upon judging a start condition for the fuel cut. CONSTITUTION:The power of an engine 10 is transmitted to driving wheels via a torque converter 12 equipped with a lock-up clutch 32, and a belt type continuously variable transmission equipped with a power transmission belt 38 and an auxiliary transmission 39. Also, the lock-up clutch 32 and the belt type continuously variable transmission are respectively controlled by the first electronic control device 42 via the first and second solenoid valves 48 and 50, and a linear solenoid valve 52. Furthermore, the second electronic control device 100 controls the open and close operation of a fuel injection valve 112. At the time of speed reduction with fuel supply cut, the lock-up clutch 32 is caused to slip. In this case, when a start condition for the fuel supply cut is judged to be satisfied, slip control and fuel cut control are sequentially permitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip control device for a direct coupling clutch for a vehicle.

[0002]

2. Description of the Related Art In a vehicle equipped with a hydraulic power transmission having a direct coupling clutch such as a torque converter with a lockup clutch and a fluid coupling with a lockup clutch in a power transmission path, the throttle valve opening is substantially zero. There is a case where fuel cut control means is provided for shutting off the supply of fuel to the engine during the deceleration traveling and the engine rotation speed exceeds a predetermined value. In such a case, it is possible to increase the fuel cut period by increasing the engine speed by engaging the direct coupling clutch to improve fuel efficiency.However, the fuel cut is executed when the direct coupling clutch is fully engaged. Then, vibration called a shock or hiccup occurs and the drivability of the vehicle is impaired. Therefore, normally, slip control is performed in which the direct coupling clutch is in a half-engaged state during the period in which the fuel cut is performed. For example, the device described in Japanese Patent Laid-Open No. 64-112073 is that.

[0003]

By the way, in the conventional slip control device as described above, the shock generated in connection with the fuel cut at the time of deceleration traveling may not always be sufficiently suppressed. That is, when the fuel cut control is started at the start of deceleration traveling,
The direct coupling clutch that was in the engaged state up to that point is controlled to be in the semi-engaged state, but since there is an operation delay time from the slip control start command until the slip of the direct coupling clutch actually starts, This is because the fuel cut is started when the direct coupling clutch is still in the engaged state.

The present invention has been made in view of the above circumstances. An object of the present invention is not to cause shock or hiccup even if the fuel cut control is executed during deceleration running and impair drivability. Another object of the present invention is to provide a slip control device for a direct coupling clutch for a vehicle.

[0005]

In order to achieve such an object, the gist of the present invention is that a direct connection is inserted in a power transmission path as shown in FIG. 1 showing the gist of the invention. In a vehicle having a fluid transmission with a clutch and fuel cut control means for cutting off fuel supply to the engine when the engine speed is higher than a predetermined value during deceleration traveling, the fuel cut control means cuts off fuel supply. A slip control device for slipping the direct coupling clutch during a decelerated traveling period, which comprises:
Fuel cut start determination means for determining whether the fuel cut start condition by the fuel cut control means is satisfied, and (b) permitting execution of slip control of the direct coupling clutch based on the determination by the fuel cut start determination means. And (c) fuel cut permission means for permitting the fuel cut operation by the fuel cut control means based on the start of the slip control of the direct coupling clutch.

[0006]

With this configuration, when the fuel cut start determination means determines that the fuel cut start condition is satisfied, the slip control permission means executes the slip control of the direct coupling clutch based on the determination. Allow Then, the fuel cut permission means permits the fuel cut control operation by the fuel cut control means based on the start of the slip control of the direct coupling clutch.

[0007]

Therefore, according to the present invention, since the fuel cut control operation by the fuel cut control means is started based on the permission by the fuel cut permission means, the output torque of the engine is reduced by the fuel cut control. When this is done, the direct-coupling clutch is reliably in the slipping state, so that the deterioration of the drivability of the vehicle due to the vibration called shock or hiccup is eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a diagram showing a vehicle power transmission device to which an embodiment of the present invention is applied. In the figure, the power of the engine 10 is transmitted to the drive wheels via a torque converter 12 with a lock-up clutch, a belt type continuously variable transmission 14, a differential gear device (not shown) and the like.

The torque converter 12 is the engine 1
Pump impeller 18 connected to zero crankshaft 16
A turbine impeller 22 fixed to the input shaft 20 of the belt type continuously variable transmission 14 and rotated by receiving oil from the pump impeller 18, and a housing which is a non-rotating member via a one-way clutch 24. A stator wheel 28 fixed to 26 and a lockup clutch 32 connected to the input shaft 20 via a damper 30 are provided. The disengagement side oil chamber 3 rather than the engagement side oil chamber 35 in the torque converter 12
When the hydraulic pressure in 3 is increased, the lockup clutch 32
Are disengaged, torque is transmitted at an amplification factor according to the input / output rotational speed ratio of the torque converter 12.
However, when the oil pressure in the engagement-side oil chamber 35 is higher than that in the disengagement-side oil chamber 33, the lock-up clutch 32 is engaged, so that the input / output members of the torque converter 12, that is, the crankshaft 16 and the input. The shaft 20 is directly connected.

The belt type continuously variable transmission 14 includes the input shaft 2
0 and an output shaft 34, a pair of variable pulleys 36 and 37 having a variable effective diameter, a transmission belt 38 wound around the variable pulleys 36 and 37, and, for example, two forward gears and one reverse gear to switch to any gear stage. And the auxiliary transmission 39. Then, a shift control hydraulic control circuit 44 for controlling the gear stage of the auxiliary transmission 39 of the belt type continuously variable transmission 14 and an engagement control hydraulic control for controlling the engagement of the lockup clutch 32. And a circuit 46. The hydraulic control circuit 44 for shift control includes a first solenoid valve 48 and a second solenoid valve that are on / off driven by a solenoid No. 1 and a solenoid No. 2, respectively, as described in, for example, Japanese Patent Application Laid-Open No. 2-212656. Fifty
The belt type continuously variable transmission 1 is provided by a combination of the operations of the first solenoid valve 48 and the second solenoid valve 50.
The gear shifting direction and the gear shifting speed of No. 4 are controlled.

Further, the engagement control hydraulic control circuit 46 includes a linear solenoid valve 52 operated by a solenoid No. 3 which is a linear solenoid, a release side position for releasing the lockup clutch 32, and the lockup clutch 32. A switching valve 54 that is switched to an engagement-side position that engages the valve, and a regulator pressure P _cl that is generated according to a throttle valve opening degree by a clutch pressure regulating valve (not shown) in the shift control hydraulic control circuit 44. It is provided with a slip control valve 56 that uses the original pressure. The linear solenoid valve 52 uses a constant modulator pressure P _modu generated in the shift control hydraulic control circuit 44 as a _source pressure, and a drive current I from the first electronic control unit (ECT) 42.
An output pressure P _lin having a magnitude corresponding to the magnitude of _sol is continuously generated, and this output pressure is applied to the switching valve 54 and the slip control valve 56.

The switching valve 54 includes a spring 58 for urging a spool valve element (not shown) toward a release side position,
The first port 60 to which the regulator pressure P _cl is supplied
And a second port 62 to which the output pressure of the slip control valve 56 is supplied and a third port 64 connected to the release side oil chamber 33.
And a fourth port 66 connected to the engagement side oil chamber 35 and a fifth port 68 connected to the drain. When the output pressure P _lin of the linear solenoid valve 52 supplied to the switching valve 54 falls below a predetermined constant value, the spool valve element is positioned at the release side position according to the urging force of the spring 58. , The second port 62 is closed, and the first port 60 and the third port 64, and the fourth port 66 and the fifth port 68 are made to communicate with each other. Therefore, when the output pressure P _lin of the linear solenoid valve 52 that acts on the spool valve element of the switching valve 54 falls below a predetermined constant value, the spool valve element of the switching valve 54 releases according to the biasing force of the spring 58. The hydraulic pressure P _off in the disengagement side oil chamber 33 is set to the regulator pressure P _cl, and at the same time, the hydraulic pressure P _on in the engagement side oil chamber 35 is set to the atmospheric pressure so that the lockup clutch 32 is opened. To be released. However, when the output pressure P _lin of the linear solenoid valve 52 acting on the spool valve element of the switching valve 54 exceeds a predetermined constant value, the spool valve element of the switching valve 54 resists the biasing force of the spring 58. Are switched to the engagement side position to close the fifth port 68 and to connect the first port 60 and the fourth port 66, and the second port 62 and the third port 64, respectively. Therefore, the hydraulic pressure P _on in the engagement side oil chamber 35 is set to the regulator pressure P _cl, and at the same time, the hydraulic pressure P _off in the disengagement side oil chamber 33 is pressure controlled by the slip control valve 56 to lock-up clutch 32.
Is slip controlled or released.

The slip control valve 56 has a spring 70 for urging a spool valve element (not shown) toward the output pressure increasing side. The oil pressure P _on in the engagement side oil chamber 35 is applied to the spool valve element in order to generate a thrust force toward the output pressure increasing side, and at the same time, in order to generate a thrust force toward the output pressure decreasing side. The oil pressure P _off in the release side oil chamber 33 and the output pressure P _{lin of the} linear solenoid valve 52
Are operated respectively. Therefore, in the slip control valve 56, the differential pressure ΔP (= P _on −P _off ) corresponding to the slip amount is determined by the linear solenoid valve 5 as shown in Formula 1.
It operates so as to have a value corresponding to the output pressure P _{lin of} 2.
Here, in Formula 1, F is the urging force of the spring 70,
A ₁ is the pressure receiving area of the oil pressure P _on in the spool valve, A ₂
(However, A ₁ = A ₂ ) is the pressure receiving area of the hydraulic pressure P _off , and A ₃ is the pressure receiving area of the output pressure P _lin .

[0014]

[Number 1] _{ΔP = P on -P off = (} A 3 -A 1) P lin -F / A 1

Therefore, in the engagement control hydraulic control circuit 46 configured as described above, the hydraulic pressure P _on in the engagement side oil chamber 35 and the hydraulic pressure P _off in the release side oil chamber 33 are as shown in FIG.
As shown in, the output pressure P _lin of the linear solenoid valve 52 is
The linear solenoid valve 52
The switching control of the switching valve 54 and the slip control of the lockup clutch 32 after the switching valve 54 is switched to the engagement position can be performed by the output pressure P _lin of the above.

The first electronic control unit 42 includes a CPU 82, R
OM84, RAM86, interface not shown
A so-called microcomputer consisting of
Is a slot provided in the intake pipe 80 of the engine 10.
Throttle sensor 88 for detecting the opening of the valve, engine
Engine rotation speed sensor 9 for detecting the rotation speed of 10
0, the rotational speed of the input shaft 20 of the belt type continuously variable transmission 14
Input shaft rotation sensor 92 for detecting, belt type continuously variable transmission 1
4 output shaft rotation sensor for detecting the rotation speed of the output shaft 34
94, the operating position of the shift lever 96, that is, L, S,
Operation to detect any of D, N, R and P ranges
From the position sensor 98, the throttle valve opening θ _thBelief
No., engine speed N_e(Pump impeller rotation speed N_P)
Signal, input shaft rotation speed N_in(Turbine impeller rotation speed
Degree N_T), Output shaft rotation speed N_outBelief
No., operating position P of shift operating lever 96_sThe signal that represents
Each is to be supplied. First electronic control unit
The CPU 82 of the storage device 42 uses the temporary storage function of the RAM 86.
According to the program stored in advance in the ROM 84 while using
Process the input signal to change the speed of the belt-type continuously variable transmission 14.
Control of the control and lockup clutch 32 is executed.
For the purpose of the first solenoid valve 48, the second solenoid valve 50 and the linear
Each of the solenoid valves 52 is controlled. With the above shift control
Is the actual shift based on the shift diagram stored in the ROM 84 in advance.
Rotor valve opening θ_thAnd output shaft rotation speed N_outCalculated from
Determine target engine speed based on the vehicle speed SPD
The actual engine speed is N_eIs the goal engine
The first solenoid valve 48, the second solenoid
Drive the valve 50.

In the vehicle of this embodiment, the air-fuel ratio of the air-fuel mixture sucked into the engine 10 is controlled by the second electronic control unit 100. A signal representing the intake air amount Q is supplied to the second electronic control unit 100 from an intake air amount sensor 102 provided in the intake pipe 80, and a throttle sensor 8 provided in the intake pipe 80 is supplied.
A signal indicating the throttle valve opening θ _th is supplied from 8. Further, a signal S _O2 representing the concentration of oxygen contained in the exhaust gas is supplied to the second electronic control unit 100 from an oxygen sensor 104 provided in an exhaust pipe (not shown).

The second electronic control unit 100, like the first electronic control unit 42, has a CPU 106, a ROM 108, and a RAM.
A microcomputer including a CPU 1
06 determines the basic injection time T _p on the basis of the actual engine speed N _e and the intake air amount Q from the relationship stored in the ROM 108 in advance, while when the oxygen amount of the exhaust gas is on the lean side. Although the fuel injection amount is increased, when it becomes the rich side, the fuel injection amount is decreased to generate an air-fuel ratio feedback correction signal that makes the air-fuel ratio the ideal air-fuel ratio, and based on this air-fuel ratio feedback correction signal, the above The basic injection time T _p is corrected, and the fuel is injected from the fuel injection valve 112 into the intake pipe 80 for the corrected injection time T _F. In addition, the second electronic control unit 100 controls the engine speed N during deceleration of the vehicle in order to save fuel.
_{When e} is higher than the preset fuel cut rotation speed _Ncut and the lockup clutch 32 is slipped, the fuel supplied from the fuel injection valve 112 to the engine 10 is shut off. In this example,
The second electronic control unit 100 functions as fuel cut control means.

The essential parts of the operation of the first electronic control unit 42 and the second electronic control unit 100 will be described in detail below with reference to the flow charts of FIGS.

FIG. 4 shows a fuel cut control routine executed by the second electronic control unit 100. Figure 4
In this routine, the throttle valve opening θ _th , the intake air amount Q, the fuel cut permission signal SF _cut, etc. are read in steps not shown. In step SF1,
Based on the input signal, it is determined whether the fuel cut start condition is satisfied. For example, it is determined whether or not the throttle valve opening degree θ _th is equal to or lower than a determination reference value set near zero in advance and the engine rotation speed N _e is higher than a preset fuel cut rotation speed N _cut. .. If the determination in step SF1 is NO, after the contents of the fuel cut request flag F _k is cleared to "0" in step SF2, the fuel cut operation is prohibited at step SF3.

However, if the determination at step SF1 is affirmative, at step SF4, the content of the fuel cut request flag F _k is set to "1" and a signal representing the content of the fuel cut request flag F _k. SF _k is output to the first electronic control unit 42. Then
In step SF5, whether the contents of the fuel cut permission flag F _cut represented by fuel cut permission signal SF _cut from the first electronic control unit 42 is "1" is determined. If the determination in step SF5 is negative, the routine is terminated after step SF3 is executed. However, if the determination in SF5 is affirmative, the fuel cut is executed in step SF6, and the fuel supply from the fuel injection valve 112 is cut off.

Next, the operation of the first electronic control unit 42 will be described with reference to FIG.
And it demonstrates according to the flowchart of FIG. First,
In steps not shown, the throttle valve opening θ _th , the engine speed N _e , which is the state quantity of the running vehicle,
The input shaft rotation speed N _in , the output shaft rotation speed N _out , the signal SF _k from the second electronic control unit 100, etc. are read.
In step SS1, it is determined whether or not the throttle valve opening θ _th is substantially an idle opening (substantially zero). When the idle switch is provided, the determination may be made based on the output of the switch.

If the determination in step SS1 is negative, it means that the accelerator pedal has been depressed and the vehicle is in a traveling state, so that normal control is executed in step SS2. In this normal control, the actual throttle valve opening θ _th
The lockup clutch 32 is released, engaged, or slips depending on whether the vehicle state specified by the vehicle speed SPD or the output shaft rotation speed N _out belongs to a prestored region shown in FIG. 6, for example. To be made.
The lockup clutch 32 is released during the shift period of the auxiliary transmission 39.

However, if the determination in step SS1 is affirmative, whether or not the content of the fuel cut request flag F _k represented by the signal SF _k from the second electronic control unit 100 is "1" in step SS3. Is determined. If the determination in step SS3 is negative,
Since the fuel cut condition is not satisfied, in step SS4 the lockup clutch 32
Is released. However, if the determination in step SS3 is affirmative, the deceleration slip control is executed in step SS5, the lockup clutch 32 is slipped when the vehicle is decelerating, and the engine speed N _e is increased to increase the fuel. The cut period is extended and shocks are alleviated.

In the subsequent step SS6, the fuel cut permission routine is executed to output the fuel cut permission signal SF _cut representing the fuel cut permission flag F _cut according to a predetermined condition. FIG. 7 shows an example of the fuel cut permission routine. In the figure, in step SA1, the lockup clutch 32
The slip rotation speed ΔN (= N _in −N _e ) of
In the subsequent step SA2, it is determined whether or not the slip rotation speed ΔN is within a predetermined range from a preset lower limit value α to an upper limit value β. The lower limit value α and the upper limit value β are set in order to determine that an actual rotation difference has occurred due to the slip control of the lockup clutch 32.

If the determination in step SA2 is negative, the content of the fuel cut permission flag _Fcut is cleared to "0" in step SA3. But,
If the determination in step SA2 is affirmative, in step SA4 the fuel cut permission flag F _cut
Is set to “1”, and a signal SF _cut representing the fuel cut permission flag F _cut is output to the second electronic control unit 100. That is, in this routine, when the slip rotation speed ΔN is within a predetermined range from the lower limit value α to the upper limit value β, it is determined that the slip control of the lockup clutch 32 is operating stably, and the fuel cut permission is given. The content of the flag _Fcut is set to "1".

In the present embodiment, by repeating the above steps, when it is determined in step SF1 corresponding to the fuel cut start determination means that the fuel cut start condition is satisfied, the slip control permission means is provided. In step SS3 corresponding to, the execution of the slip control of the lockup clutch 32 is permitted based on the determination. Then, in step SA4 corresponding to the fuel cut permission means, the fuel cut control operation by the second electronic control unit 100 is permitted based on the actual start of the slip control of the lockup clutch 32.

Therefore, since the fuel cut control operation by the second electronic control unit 100 is started based on the permission in step SA4 corresponding to the fuel cut permission means, as shown in the time chart of FIG.
When the fuel cut control is started, the lock-up clutch 32 is surely in the slip state, so that the deterioration of the drivability of the vehicle due to the vibration called shock or hiccup is eliminated.

Incidentally, FIG. 9 shows a time chart at the start of slip control of the lockup clutch during deceleration travel in a vehicle equipped with a conventional slip control device.
As is clear from the figure, when the fuel cut control is started, the lockup clutch 32 is still in the engaged state due to the response delay, so that a vibration called a shock or a hiccup shown in B of the figure occurs, As a result, the drivability of the vehicle was sometimes impaired.

Next, another embodiment of the present invention will be described. In the following description, the same parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 10 shows FIG.
5 shows another example of the fuel cut permission routine shown in FIG. In step SB1 of the figure, the elapsed time from when it is determined in step SS1 that the throttle valve opening θ _th is in the idle state and in step SS3 that the content of the fuel cut request flag F _k is "1". It is determined whether CT has reached a preset determination reference value CT _O. This determination reference value CT _O is locked after the determination in step SS3 is affirmed and the slip control command for the lockup clutch 32 is issued so that the slip control of the lockup clutch 32 can be determined to be stable. It is set sufficiently longer than the delay time until the up clutch 32 is actually slipped.

If the determination in step SB1 is negative, the content of the fuel cut permission flag _Fcut is cleared to "0" in step SB2. But,
If the determination in step SB1 is affirmative, in step SB3 the fuel cut permission flag F _cut
Is set to “1”, and a signal SF _cut representing the fuel cut permission flag F _cut is output to the second electronic control unit 100. That is, in this routine, the lockup clutch 3 is activated from the slip control command.
After the time for the slip control of 2 to operate stably,
The content of the fuel cut permission flag _Fcut is set to "1". Also in this embodiment, the same effect as that of the above-mentioned embodiment can be obtained.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other aspects.

For example, in the vehicle of the above-mentioned embodiment, the first
Although the electronic control unit 42 and the second electronic control unit 100 are provided, a single control unit capable of operating both of them may be provided.

Further, step SA in the embodiment shown in FIG. 7 described above.
In 2, it may be determined whether or not the slip rotation speed ΔN is larger than the predetermined value A. The predetermined value A is set to a value of several rpm, for example. Even in this case, if the lock-up clutch 32 is in the engaged state where slippage begins to occur, even if the transmission torque due to the fuel cut increases, the shock is alleviated due to slippage.

While a cooling water temperature sensor for detecting the cooling water temperature of the engine 10 is provided, the above-mentioned step S of FIG. 5 is performed.
Between S3 and SS4, it is determined whether the engine cooling water temperature Tw exceeds a preset value Tα, and if not, the lockup clutch 32 is released in step S.
A new step may be provided to execute S4 and, if it exceeds, execute step SS4. With this configuration, when the engine cooling water temperature Tw is equal to or lower than the set value Tα, the lockup clutch 32 is released, the engine rotation speed N _e falls below the fuel cut rotation speed N _cut , and the fuel cut is restored. Therefore, when traveling on a long downhill, it is possible to solve the problem that the engine malfunction and the heater effectiveness are reduced due to the decrease in water temperature.

In the above new step, instead of determining whether the engine water temperature Tw exceeds the set value Tα, it is determined whether the vehicle compartment temperature T _rm exceeds the set value Tβ. Alternatively, it may be replaced by determining whether or not the vehicle compartment temperature T _rm exceeds the set value T _set of the automatic air conditioner by a predetermined value γ, and a step depending on whether both of these determinations are affirmed. You may make it execute SS4. By such steps, it is judged that the heater is not effective due to the decrease in the cooling water temperature Tw, and the fuel cut is restored based on the judgment.
When running on a long downhill, it is possible to solve the problem that the engine malfunctions and the effectiveness of the heater decreases due to the decrease in water temperature.

Before and after step SA2 in FIG. 7 and step SB1 in FIG. 10 described above, the steps described in paragraphs 35 and 36 above are inserted so that the engine cooling water temperature Tw is lower than the set value Tα. When it is determined that the heater is not effective or the cooling water temperature Tw is decreased, step SA3 or SB2 is performed.
May be executed. Even in this case, the same effect as above can be obtained.

Further, in the above-mentioned embodiment, the vehicle in which the belt type continuously variable transmission 14 is provided at the rear stage of the torque converter 12 has been described, but the belt type continuously variable transmission 14 is replaced with a planetary gear type. The stepped transmission of 1 may be provided.

Further, the torque converter 1 of the above-mentioned embodiment.
Instead of 2, a flute coupling with a lock-up clutch may be provided.

The above description is merely one embodiment of the present invention, and the present invention can be variously modified without departing from the gist thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing a summary of the present invention.

FIG. 2 is a diagram showing a control device of an embodiment of the present invention and a vehicle power transmission device to which the control device is applied.

3 is a diagram illustrating an engagement control hydraulic control circuit of FIG. 2, wherein an output pressure P _lin of a linear solenoid valve, an engagement side oil chamber hydraulic pressure P _{on of a} lockup clutch, and a release side oil chamber hydraulic pressure P _off;
It is a figure explaining the relationship with.

FIG. 4 is a flowchart illustrating an essential part of the operation of the second electronic control unit of FIG.

FIG. 5 is a flowchart illustrating a main part of an operation of the first electronic control unit of FIG.

FIG. 6 is a diagram illustrating an operating region of a normal control of a lockup clutch included in the torque converter of FIG.

FIG. 7 is a flowchart illustrating in detail the fuel cut permission routine of FIG.

8 is a time chart explaining a phenomenon obtained as a result of the operation shown in FIG.

FIG. 9 is a diagram corresponding to FIG. 8 in a conventional control device.

FIG. 10 is a diagram corresponding to FIG. 7 in another embodiment of the present invention.

[Explanation of symbols]

10 engine 14 automatic transmission 32 lock-up clutch (direct coupling clutch) 42 first electronic control unit (slip control unit) 100 second electronic control unit (fuel cut control unit) step SF1 fuel cut start determination unit step SS3 slip control permission unit Step SA4 Fuel cut permission means

Claims (1)

[Claims] 1. A vehicle having a hydraulic transmission with a direct coupling clutch inserted in a power transmission path, and fuel cut control means for cutting off fuel supply to the engine when the engine speed is higher than a predetermined value during deceleration traveling. In a slip control device for slipping the direct coupling clutch during a deceleration traveling period in which fuel supply is cut off by the fuel cut control means, it is determined that a condition for starting fuel cut by the fuel cut control means is satisfied. Fuel cut start determination means, a slip control permission means for permitting execution of slip control of the direct coupling clutch based on the determination by the fuel cut start determination means, and slip control of the direct coupling clutch being actually performed. Based on the fuel cut control means And a fuel cut permitting means for permitting the fuel cut control operation by the slip control device for a vehicle direct coupling clutch.