JPS6012345A - Start control method of car with automatic clutch - Google Patents

Abstract

PURPOSE:To obtain a smooth clutch operation and advance responsiveness by determining the operation speed of a clutch actuator based on the depressed quantity of an accelerator pedal. CONSTITUTION:The depressed quantity of a clutch pedal 12 is detected by a sensor 12a, the engine load due to the change of the engaging condition of a clutch 2 is detected, and the engagement control of the clutch is stopped. In order to detect an increase of the engine load, the change rate of the engine speed is detected, thus detecting the negative change rate. That is, a processor 9a reads the engine speed from an engine speed sensor 10 via an input port 9d, calculates the change rate which is the difference with the previous engine speed previously read and stored in a RAM9e, and determines whether it is negative or not.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a start control method for a vehicle equipped with an automatic clutch, which controls the clutch and engine during the start process of a vehicle equipped with an automatic clutch. This invention relates to a start control method for a vehicle with an automatic clutch that prevents the engine from running dry, does not deteriorate the start response, and prevents the engine from stopping or knocking during the start process.

(Prior Art) In recent years, vehicles equipped with automatic transmissions have been widely used to facilitate vehicle driving operations. Such vehicles use automatic clutches, such as those using a torque converter or those in which a friction clutch (for example, a dry single-plate clutch) is driven by a fluid-controlled actuator.

Conventional methods for controlling this type of automatic clutch include methods that gradually change the clutch engagement state as the engine speed increases (for example, Japanese Patent Publication No. 50-12648);
A system has been proposed in which the engagement speed of the clutch is changed depending on the engine rotational speed (for example, Japanese Patent Laid-Open No. 52-5117), with the aim of smoothing the starting operation.

(Problems with the prior art) On the other hand, in this type of vehicle with an automatic clutch, the driving operation is no different from that of a conventional vehicle with an automatic transmission equipped with a torque converter, and the driver does not have to press the accelerator pedal when starting. Depressing the accelerator pedal a considerable amount and continuing to depress it until a certain speed is achieved means that the torque converter is constantly under load on the engine in the driving range, so no matter how much you depress the accelerator pedal, the engine speed will rise dramatically. Furthermore, by increasing the engine speed and increasing the slip ratio of the converter, a large torque ratio can be obtained and acceleration torque is advantageous.

However, in vehicles equipped with automatic clutches that use friction clutches, the clutch engagement operation is performed after the engine speed increases, so when the clutch first starts to engage, the engine speed increases by a corresponding amount and the engine speed increases. Moreover, since the vehicle itself is not moving at all during this period, the engine may run dry, and the clutch slips considerably during the half-clutching process, which reduces the wear life of the clutch and furthermore leads to deterioration of fuel efficiency. was occurring. Second, it takes a certain amount of time for the engine speed to increase after the driver depresses the accelerator pedal, and since the clutch is controlled in accordance with this increase, there is a drawback that the starting response is significantly degraded. Moreover, if the starting response was poor, the car would not start moving easily, so the driver would have to press the accelerator pedal even more, which would exacerbate the first problem.

(Object of the Invention) An object of the present invention is to provide a method for controlling the start of a vehicle with an automatic clutch that prevents the engine from revving during the start process, has good start response, and does not cause the engine to stop or knock.

(Summary of the invention) The present invention is based on a previously filed invention. That is, in the invention of the previously filed application, firstly, the amount of depression of the accelerator pedal is detected, and the operation speed of the clutch actuator is determined from the detected amount of depression to ensure smooth latch operation and start response, and secondly, the amount of depression of the accelerator pedal is detected, and the operating speed of the clutch actuator is determined from the detected amount of depression, thereby ensuring smooth latch operation and starting response. Sets the engine speed, detects the engine speed, and controls the opening and closing of the engine's throttle valve based on the difference between the two engine speeds to keep the engine speed at the appropriate speed, preventing engine racing and worsening fuel efficiency. We are trying to prevent this.

In the invention of the previously filed application alone, the engine speed is controlled to be within the appropriate engine speed, so when starting slowly on a slope or driving at low speed, the engine output may be insufficient for the vehicle load, causing knocking or This may cause the engine to stall.

For this reason, in the present invention, in addition to the previously applied invention, the engine load (that is, vehicle load) caused by a change in the engagement state of the clutch is detected, and the clutch connection control is stopped.

In one embodiment of the present invention, in order to detect the increase in engine load, the rate of change in the engine speed is detected, and it is detected that the detected rate of change has become negative. In order to detect such an increase in engine load, the amount of engagement of the friction clutch is detected, the limit engine speed corresponding to this amount of engagement is determined, and the detected engine speed is determined to be below the limit engine speed. I'm trying to detect this.

Embodiment FIG. 1 is a block diagram of an embodiment for realizing the present invention. In the figure, in a 1#'i engine, a throttle valve A/A for controlling the amount of intake gas (air or mixture) is shown. Flywheel 1B.

A throttle valve actuator 1b is provided.

2 is a clutch body, which is composed of a well-known friction clutch and has a release lever 2a; 3 is a clutch actuator; in order to control the engagement amount of the clutch body 2, its piston rod 3a is a release lever; 2a
It is what drives the.

Reference numeral 4 is a hydraulic mechanism), and reference numeral 5 is a transmission actuator, which will be described later. 6 is a synchronous mesh transmission,
It is driven by the transmission actuator 5 and performs a gear change operation, and includes an input shaft 6a connected to the clutch 2, an output shaft (drive shaft) 6b1, and a gear position (gear position).
The gear position sensor 6c detects the gear position sensor 6c. 7 is operated by the driver using the selector lever, "N" range (neutral position), rDJ range (automatic shift), "1"
Range (1st speed), 2-lunge (2nd speed), 6th range (1st, 2nd, 3rd automatic transmission), R, R, J range (reverse) are selected by lever position control. A selection signal SP indicating the selected range is output by the selection sensor 7a.

8a is a rotation sensor which detects the rotation speed of the input shaft 6a; 8b is a vehicle speed sensor which detects the vehicle speed from the rotation speed of the drive shaft 6b; and 10 is an engine rotation sensor. , which is used to detect the rotation speed of the engine 1 by detecting the rotation speed of the flywheel 1a. 9 is an electronic control unit composed of a microcomputer, and a processor 9 that performs arithmetic processing.
a, and a read-only memory (ROM) 9b that stores control programs for controlling the transmission 6 and clutch 6.
, an output capo) 9c, an input capo) 9d, and a random access memory (RAM) 9e for storing calculation results, etc.
Address/data bus (BUS) 9f that connects these
It is made up of. The output port 9c is a throttle valve actuator 1b, a clutch actuator 6,
A drive signal SDV is connected to the hydraulic mechanism 4 and the transmission actuator 5 and drives them.

Outputs CDV, PDV, and ADV.

On the other hand, the input capo 9d includes various sensors 6c.

7a, 8a+sl), 1o, and an accelerator pedal and a brake pedal, which will be described later, and receive detection signals from these pedals. 11 is an accelerator pedal, which has a sensor 11a (potentiometer) that detects the amount of depression of the accelerator pedal 11, and 12 is a brake pedal), a sensor 1 that detects the amount of depression of the brake pedal 12.
2a (switch).

Figure 2 shows the aforementioned clutch and transmission actuators 3 and 5.
, is a block diagram of the hydraulic mechanism 4. In the figure, T is a tank, P is a hydraulic pump, and vl is an on-off valve, which constitute the hydraulic mechanism 4.

The clutch actuator 3 includes a cylinder 33, a piston 31, and a piston rod 51a (3a) whose one end is connected to the piston 31 and whose other end is connected to the release lever <-2a of the clutch 2. The selection chamber 33a is an on-off valve V2. It communicates with the pump P (via the on-off valve V□) and with the tank T via the on-off valve v8 and the on-off valve ■4 controlled by the nozzle ft1lJ. It is piped so that it communicates with the T side.In addition, 3
A position sensor 4 detects the position of the piston rod 31a and outputs the engagement amount of the clutch 2.

Therefore, when the on-off valve v9 is opened in response to the drive signal CDVi, hydraulic pressure is applied to the chamber 55a, the piston 31 moves to the right, the clutch is turned off, and the drive signal CDV2.
Open/close valve V8 from CDV3K. When opening V4, chamber 5
The hydraulic pressure of Sa is released, the hyston 31 moves to the left, and the clutch 2 is turned on. Opening/closing valve V4 is drive signal CDV
3, the clutch 2 is gradually turned on (contacted).

Further, the transmission actuator 5 includes a select actuator 50 and a shift actuator 55.

This select and shift actuator 50 and 5
5 is configured to be able to stop in 3 positions,
It consists of stepped cylinders 55 and 58, first pistons 51 and 56, and cylindrical second pistons 52 and 57 that fit into the first pistons, a rod 51a of the first piston, and 56a is engaged with an internal lever of the transmission 6 (not shown). Both actuators 50 and 55 have respective chambers 55&, 53b and 58a of their stepped cylinders 53 and 58, respectively.

When hydraulic pressure is applied to chambers 58b, the chambers 53a and 58a are in the neutral state shown in FIG. Further, when hydraulic pressure is applied to the chambers 53b and 58b, only the first pistons 51 and 56 move to the left in the figure.

The chambers 53a and 53b of the select actuator 50 communicate with the pump P (via the on-off valve □) or the tank T via flow path switching valves vlS and V6, respectively. or,
The shift actuator 55 also connects the chambers 58a and 58b to the pump P (opening/closing valve
) or to the tank T, respectively.

Therefore, in the state shown in the figure, the transmission 6 is in the neutral state, and the drive signal ADV4 is used to switch the multi-channel switching valve v7 to the pump P.
Turn the multi flow path switching valve ■8 on the side using the drive signal ADV5.
When connected to the T side, the transmission becomes 4th speed. When there is a shift signal from the 4th speed state to the 5th speed, firstly, the drive signals ADV3 and ADV4 connect the multi-flow path switching valves v8 and V to the pump P side, thereby causing a shift operation. Return the chaser 55 to the neutral state shown. Next, drive signal AD
V1 moves the multi-flow path switching valve v6 to the pump P side, and the drive signal A
DV2 connects the flow path switching valve vb to the tank T side, and operates the select actuator 50 to the 5th speed-reverse select position. Next, the drive signal ADV5 connects the multi-channel switching valve 8 to the pump P side, the drive signal ADV4 connects the multi-channel switching valve 7 to the tank T side, and the shift actuator 5
5 to the fifth speed position to shift the transmission to the fifth speed.

In this way, the drive signal ADV1. ADV2 and ADVI
, ADV4, flow path switching valves v, , v, o and V8. V
, and alternately actuating the select actuator 50 and the shift actuator 55, it is possible to perform a shift operation to each gear stage.

Next, the start control method of the present invention having the configuration shown in FIGS. 1 and 2 will be explained with reference to the process flow diagram in FIG. 3.

The flow on the left side of Figure 6 is the clutch control flow diagram.
The flow on the right side of FIG. 3 is a throttle control flow diagram, and both are executed in parallel.

First, before entering this process flow, while the car is already stopped, the select lever 7 is used to select the driving range (II) J, r.
IJ, r2j, ['') is specified), thereby the shift latch 2 is disconnected and the transmission 6 is set to 1.
Assume that the gear is shifted to

That is, the select lever 7 is in the driving range (for example, rDJ
When the selection signal SP for the "D" range is input from the position sensor 7a and input from the position sensor 7a, the processor 9a inputs the input signal from the input capacitor 9d via the BUS 9f.
9 Store in e. Next, the processor 9a outputs a drive signal ADV to the transmission actuator 5 from the output capacitor 9c, drives the transmission actuator 5, and shifts the transmission 6 to 1st speed.
Receives the Numazawa gear signal GP from the input port 9d,
Transmission 6 d! It is detected that the gear has been shifted to 1st speed, and this is stored in l14AM9e.

■The processor 9a reads the depression amount AP from the sensor 11a of the accelerator pedal/L/11 via the input capo) 9d,
Store in RAM9e. Also, clutch actuator 3
The engagement amount CLT is measured from the position sensor 34 of
and stores it in the RAM 9e.

Next, the processor 9a uses the depression amount AP stored in the RAM 9e and the predetermined depression amount IDL in the idle state.
Compare with E. If AP>IDLE, it is determined that the accelerator pedal 11 has been depressed and a start operation has been instructed; conversely, if AP≦IDLE, it is determined that a start operation has not been instructed.

(2) If a start operation is not instructed, the processor 9a compares the clutch engagement amount CLT in the RAM 9e with the clutch engagement amount CLTo in the disengaged state. If CLT>CLTo, if clutch 2 is not disengaged, λ and others are operated to disengage clutch 2. That is, in order to disengage the clutch, the processor 9a outputs the drive signal CDV2. CD
VI side on-off valve v8. Close v4, drive signal PDV,
CDV1 on-off valve v1. Vg is opened, hydraulic pressure is applied to the chamber 55a, the piston 31 is moved to the right, and the clutch 2 is
is prohibited.

After the clutch 2 is disengaged and if CLT≦CL To, the process ends and returns to step (2).

(2) On the other hand, if it is determined in step (2) that a start operation has been instructed, the processor 9a determines the operating speed of the clutch actuator 3. Map data of the operating speed is stored in advance in the RAM 9e. That is, as shown in FIG. 4, since the correspondence relationship between the operation speed f1 and the depression of the accelerator pedal 11 - jtAP is stored, the processor 9a
indexes this map data from the depression amount AP stored in the RAM 9e and calculates the corresponding operation speed f1.

0 Next, the processor 9a reads the engine rotation speed No(t) from the rotation sensor 10 via the input capo) 9d,
The rate of change dNe, which is the difference from the previous engine speed No. (t-1) read last time and stored in the RAM 9e, can be calculated using the following equation.

dNe = Ne (t) - Ne (t-1) (11) Then, the engine rotation speed of the RAM 9e is set to Ne (t).

0 Next, it is determined whether the rate of change dNe set by the processor 9a is negative or not. If dNe<0, that is, negative, it is determined that the engine load is increasing, and the process proceeds to step (2).

Conversely, if dNe≧0, other engine load increase detection is performed. That is, the relationship between the clutch retention amount CLT and the limit engine speed f4 that will prevent the engine from running out of output is determined in advance as shown in FIG. 7, and this is stored in the RAM 9.
Store it as map data in e. Then, the processor 9a calculates the clutch engagement amount CLT detected in step (2).
Find the corresponding limit engine speed f4 (CLT) from RAM 9e. Next, the processor 9a compares the engine speed Ne detected in step (2) with the limit engine speed f, (CLT). If the processor 9a determines that Ne<f4(CLT), it determines that the engine load has increased and the engine output is insufficient, and proceeds to step (3). In the opposite case, tNe≧f4<CLT)) Tear lever, assume that the engine load has not increased and step ■
Proceed to.

(2) If the aforementioned dNe<O or Ne<f4 (CLT), the aforementioned step (2) is completed and the operating speed f1 stored in the RAM 9e is set to zero. That is, the clutch operation speed is made zero and the clutch connection operation is stopped.

(2) Next, the processor 9a outputs the clutch drive signal CDV at the operating speed f1 and sends it to the clutch actuator 6 via the capacitor 9c, which causes the clutch actuator 3 to gradually move the piston rod 3a to the left and release the release lever. 2a gradually to the left. As a result, the engagement amount of the clutch 2 changes as shown in a in FIG. 9,
The clutch 2 goes from a disengaged state to a half-clutch state and then to an engaged state.

Note that when the operation speed f1 is zero, the operation of the clutch actuator 3 is stopped, and the clutch connection operation is stopped.

This cycle is repeated until the clutch 2 is engaged, so if the depression amount AP of the accelerator pedal 11 changes while the clutch 2 is being operated, the operating speed f1 of the clutch 2 will change accordingly, and during that time the engine load If an increase in is detected, the operation of the clutch 2 is stopped. Then, when the engine speed increases and the engine load no longer increases, the clutch 2 is again controlled to be connected at the determined operation speed f1.

In parallel with this process for controlling the clutch 2, a process for controlling the throttle valve is performed.

■The processor 9a reads the engine rotation speed Ne from the engine rotation sensor 10 via the input capo) 9d, and
Store in AM9e.

0 Next, the processor 9a compares the depression amount AP of the RAM 9e read in the above-mentioned step (2) with the depression amount IDLE in the idle link state. Processor 9a is AP≦IDL
When E is detected, it is determined that the engine is in an idling state, and the detected engine speed Ne is set as the idle speed N.
It is stored as 1 in the RAM 9e, and the process returns to step 0.

(2) On the other hand, when the processor 9& begins to detect AP>IDLE, it determines that the accelerator pedal is depressed, and sets the target engine speed. Therefore, the amount of depression A of the accelerator pedal 11 as shown in FIG. 5 is stored in advance in the RAM 9e.
Map data showing the correspondence relationship of (target engine speed N - idle engine speed N1) fs to P is stored, and the processor 9a indexes this map data and calculates the rotation speed f9 (AP) with respect to the depression amount AP. get. Next, the processor 9a reads the idle engine speed Ni stored in the RAM 9e, and calculates the target (appropriate) engine speed N by calculating the following equation.

N = Ni + fl (AP) (1) By using this stock, even if the engine speed during idle link changes due to auto choke or aging, it is possible to obtain the optimal target engine speed N. can.

Next, the processor 9a calculates the response coefficient α. Therefore, as shown in FIG. 6, the clutch engagement amount CL is stored in RAM9e.
Map data showing the correspondence relationship of the response coefficient α to T is stored, and the processor 9a reads this map data from the engagement amount CLT read in the RAM 9e in step 2, and calculates the corresponding response coefficient α. , RAM9e
Store in. The response coefficient α indicates the response characteristic for opening/closing control of the throttle valve, which will be described later, and is the clutch engagement amount CL.
The more dog-like T becomes, the more dog-like the response coefficient α becomes. That is, as the clutch torque increases, the response coefficient increases and the throttle opening/closing amount increases.

0 Next, the processor 9a compares the engine speed Ne stored in the RAM 9e in step 0 with the target engine speed N determined in step (2). Flosser 9a has Ne>N
When Ne≦N, the throttle valve is not opened enough, so the response coefficient β is set to β. The response coefficient is βj>β2>0, and the response coefficient β is the closing amount of the throttle valve.

The opening amount response coefficient β□ is set to be smaller than that to prevent notching.

0 Next, the processor 9a determines the throttle opening TH. That is, the previous throttle opening TH is stored in the RAM 9e, and the current throttle opening is calculated by the following equation.

TH=TH+ΔT(2) ΔT=α・β・(N−Ne) (31 In other words, the difference between the target engine speed and the current engine speed (
The opening/closing amount ΔT is determined by the response coefficients α and β. When N>Ne, ΔT is positive when the throttle valve is opened, that is, the opening amount; when N<Ne, when the throttle valve is closed, ΔT is negative, that is, the closing amount. Then, if N>Ne, the response becomes large when β=βt, and when N<Ne, the response becomes small when β=β1, and the response amount is in accordance with the clutch engagement amount CLT. This opening/closing amount ΔT is added to the previous throttle opening TH, and becomes the current throttle opening TH.
It is stored in RA~r9e. Along with this,
Drive signal S corresponding to throttle opening T)I via 9c
DV is applied to the throttle valve actuator 1b. With this, throttle valve actuator 1b
rotates the throttle valve to the specified throttle opening. After this, return to step ① and repeat this.

Therefore, the throttle valve gradually reaches the target opening,
The engine speed also gradually reaches the target engine speed. Responsiveness, which is the degree to which this is achieved, changes by α depending on the difference between the clutch engagement amount CLT and the engine speed, and also changes by β depending on whether the listening direction or the closing direction 75λ.

In this way, while the shift latch is being operated repeatedly by repeating steps ``■'' to ``■'', the opening and closing of the throttle knob (lube) is controlled by repeating steps ``■'' to 0, and the optimal clutch speed and engine speed are controlled. The clutch is engaged at the rotational speed, and the vehicle starts moving.

From then on, the processor 9a uses the detection signal W of the speed sensor 8b.
9d, calculates the vehicle speed V, and calculates the vehicle speed V.
The shift map is searched from the speed V of R and AM9e and the accelerator amount AP, and the optimum gear stage is set.

That is, as shown in FIG. 8, the ROM 9b stores a shift map corresponding to the vehicle speed and the accelerator amount AP as a table SM. In the figure, 1. H, m.

■ and ■ are used for each gear, the solid line is the boundary line between the gears when shifting down, and the dotted line is the boundary line between the gears when shifting down.Upshift maps and downshift maps are mixed.

The processor 9a determines the vehicle speed v1 from this shift map.
Determine the optimum gear position corresponding to AP. If this optimum gear position is different from the current gear position of the transmission 6, the processor 9a sends the clutch drive signal CDV to the clutch actuator 3 via the output capo~)9c. By applying hydraulic pressure to the chamber ssa of 33, the piston rond 3a (31a) is returned to the right, the release lever 28 is returned to the right, and the clutch is gradually disengaged as shown in FIG. 9b. shall be.

The processor 9a sends a drive signal ADV for selecting the next optimum gear to the transmission actuator 5 via the BUS 9f and the output boat 9c.

Accordingly, the transmission actuator 5 is connected to the above-mentioned hydraulic mechanism 4, and the built-in select and shift actuators 50, 55 are hydraulically controlled to operate the transmission 6 and synchronously engage the desired gear position.

Next, at the end of the speed change operation, the processor 9a sends the clutch drive signal CDV to the clutch actuator 3 as at the time of starting described above, engages the clutch, and ends the speed change operation.

In the above-described embodiment, the electronic control device 9 is configured with a single processor 9a, but it may be configured with a plurality of processors to perform distributed processing.

(Effects of the Invention) As explained above, according to the present invention, since the operation speed of the clutch actuator is determined from the amount of depression of the accelerator pedal, it is possible to achieve the effect of obtaining smooth latch operation and starting response. The system sets the appropriate engine speed, detects the engine speed, and controls the opening and closing of the engine's throttle valve based on the difference in the speeds of both engines, so the engine speed during clutch operation is adjusted to the optimum speed. It also has the effect of preventing the engine from running at 9 revs and deteriorating fuel efficiency. Furthermore, since this appropriate engine speed is proportional to the amount of depression of the accelerator pedal, there is also the effect that the start response is more in line with the driver's wishes.

Furthermore, in the present invention, the engine load due to a change in the engagement state of the clutch during the clutch engagement control is detected, and when this engine load increases, the engagement control is stopped. etc., there is no risk of knocking or stalling even if the engine output is insufficient for the vehicle load, and when the engine speed increases and the engine output becomes sufficient, the stoppage is released and the clutch is activated again. The connection control is restarted, and there is also the effect that it is possible to prevent the risk of the clutch being left unconnected on a slope or the like. In particular, the present invention is particularly effective in cases where the engine speed is controlled so that the engine speed is kept within a proper engine speed, such as in the invention of a previously filed application, since insufficient engine output is likely to occur when the vehicle starts depending on the vehicle situation. .

Although the present invention has been described by way of one embodiment, various modifications may be made within the scope of the present invention, and these are not excluded from the scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment for realizing the BA9 of the present invention, FIG. 2 is a block diagram of main parts in the configuration of FIG. 1, FIG. 3 is a processing flow diagram of an embodiment according to the present invention, and FIG. FIG. 5 is a map of accelerator pedal depression versus clutch operation speed used in the present invention. FIG. 6 is a map of accelerator pedal depression versus appropriate engine speed used in the present invention. FIG. 7 is a map diagram of the clutch engagement amount vs. limit engine speed according to the present invention, FIG. 8 is a shift map diagram for determining the gear position in the configuration shown in FIG. 1, and FIG. FIG. 2 is an explanatory diagram of clutch operation in the configuration of FIG. 1; In the figure, 1... Engine, 1b... Throttle valve actuator, 2... Clutch, 3... Clutch actuator, 6... Transmission, 7... Selector lever, 8b... ...Vehicle speed sensor, 9...Electronic control unit, 11...Accelerator pedal, 11&...Accelerator pedal sensor. Fig. 4 Accelerator〈Dall return amount AP Disconnection Whirling clutch engagement content CLT (Actuator stroke) Fig. 7 (Actuator stroke)

Claims (3)

[Claims] (1) The electronic control device detects the amount of depression of the accelerator pedal in the clutch control process, determines the operation speed of the clutch actuator from the detected amount of depression, controls the engagement of the friction clutch, and detects the engine rotation speed. A starting control method for a vehicle equipped with an automatic clutch, which controls the opening and closing of a throttle valve of the engine so as to maintain the set engine speed by comparing the engine speed with a properly set engine speed, the clutch comprising: 1. A start control method for a vehicle with an automatic clutch, comprising: detecting an engine load due to a change in the engaged state of a nuclear clutch during connection control; and stopping the connection control when the detected engine load increases. (2) In order to detect an increase in the engine load, a rate of change in the engine speed is detected, and when the detected rate of change becomes negative, the connection control is stopped. A method for controlling the start of a vehicle with an automatic clutch according to item +11. (3) In order to detect the increase in the engine load, the engagement amount τ of the friction clutch is detected, the limit engine speed corresponding to the engagement amount is determined, and the detected engine speed is set to the limit engine speed. The method for controlling the start of a vehicle with an automatic clutch according to claim 1, wherein the connection control is stopped when the rotational speed becomes lower than the rotational speed.