JP2603823B2 - Automatic clutch control system for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a control device for an automatic clutch provided in a drive system of a vehicle and electronically controlling a clutch torque, and more particularly to a shock reduction control in a case where an accelerator is suddenly returned during start acceleration. The present applicant has already proposed a large number of such automatic clutches for vehicles, for example, for an electromagnetic clutch. Most of them are in transient state such as when starting,
In the steady state after the direct connection of the clutch, the clutch torque is optimally controlled in relation to the operation of the accelerator pedal and shift lever, running conditions, engine conditions, etc., and further in combination with a manual transmission or a belt type continuously variable transmission. Appropriate control is performed. In particular, in recent years, electronic control of not only engines but also drive system clutches, transmissions, and the like has been advanced, and even automatic clutches tend to be controlled more finely.

[Prior art]

Conventionally, with respect to the clutch torque control in the start mode in the above-mentioned automatic clutch for vehicles, for example, Japanese Patent Application Laid-Open No. 60-16122
There is a prior art disclosed in Japanese Patent Application Laid-Open No. 4 (1999) -1995, which discloses that the clutch torque at the time of starting is determined by a function of the engine speed and is controlled so as to increase in proportion to the engine speed.

[Problems to be solved by the invention]

According to the control method of the prior art described above, the accelerator return at the time of starting is as follows. That is, when the accelerator is completely returned and the vehicle speed at that time has not reached the direct connection vehicle speed, the mode is switched to the drag mode and the clutch is released. For this reason, the driving force from the wheel side due to the return of the accelerator is not transmitted to the engine, and no shock due to the reversal of the driving force occurs. On the other hand, when the accelerator is returned halfway, when the vehicle is in the start mode and the clutch is substantially engaged, the effect of the reversal of the driving force is directly transmitted to the engine, and the vehicle is likely to generate a shock. This is because the accelerator opening sharply decreases during acceleration, and the shock becomes more remarkable as the accelerator opening becomes smaller thereafter. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for an automatic clutch for a vehicle which reduces a shock generated when an accelerator depressed when starting is returned halfway. And

[Means for solving the problems]

In order to achieve the above object, the present invention provides a start control system that generates a clutch torque proportional to the engine speed when the accelerator pedal is depressed in a low speed range, when the throttle is rapidly closed and the throttle opening is equal to or less than a predetermined value. Are configured to control to reduce the clutch torque once.

[Action]

Based on the above configuration, when the accelerator depressed at the time of starting is returned, the clutch torque temporarily decreases and the slip increases, so that the driving force suddenly switched in the opposite direction is not transmitted to the engine. Thus, in the present invention, the reversal of the driving force is absorbed by the slip of the clutch, and the shock can be reduced.

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, the overall configuration of a drive system in which a belt-type continuously variable transmission is combined with an electromagnetic clutch will be described. The engine 1 is connected to a continuously variable transmission 4 via an electromagnetic powder type clutch 2 and a forward / reverse switching device 3, and a set of a reduction gear 5, an output shaft 6, a differential gear 7 and an axle 8 are provided from the continuously variable transmission 4. Through the drive shaft 9. The electromagnetic powder type clutch 2 has a drive member 2a on an engine crankshaft 10 and a driven member 2b having a clutch coil 2c on an input shaft 11. And clutch coil 2c
The electromagnetic powder is coupled and accumulated in the gap between the two members 2a and 2b in a chain by the clutch current flowing through the clutch, and the clutch engagement / disengagement and clutch torque are variably controlled by the coupling force. The forward / reverse switching device 3 is synchronously meshed with a gear, a hub, and a sleeve between the input shaft 11 and the transmission main shaft 12, and includes a forward position at which the input shaft 11 is directly connected to the main shaft 12, and an input shaft. And a retracted position for transmitting the rotation of the rotation 11 to the main shaft 12 in the reverse direction. The continuously variable transmission 4 includes a main shaft 12 and a sub shaft arranged in parallel with the main shaft 12.
The primary shaft 12 is provided with a primary pulley 14 having a hydraulic cylinder 14a having a hydraulic cylinder 14a and the secondary shaft 13 is similarly provided with a secondary pulley 15 having a hydraulic cylinder 15a. A drive belt 16 is wound around both pulleys 14 and 15, and both cylinders 14a and 15a are configured as a hydraulic control circuit 17. Then, a line pressure according to the transmission torque is supplied to both cylinders 14a and 15a to apply a pulley pressing force, and the primary pressure changes the ratio of the winding diameter of the drive belt 16 to the pulleys 14 and 15 to continuously change the speed. It is configured to control. Next, an electronic control system of the electromagnetic powder type clutch 2 and the continuously variable transmission 4 will be described. An engine speed sensor 19 of the engine 1, speed sensors 21 and 22 of the primary pulley and the secondary pulley of the continuously variable transmission 4, and sensors 23 and 24 for detecting operating states of the air conditioner and the choke are provided. A shift lever 25 of the operation system is mechanically coupled to the forward / reverse switching device 3, and detects a shift position sensor for detecting each range of reverse (R), drive (D), and sporty drive (Ds).
Has 26. Further, the accelerator pedal 27 has an accelerator switch 28 for detecting an accelerator depression state, and a throttle opening sensor 29 on the throttle valve side. The various signals of the switches and the sensors are input to the electronic control unit 20 and processed by software using a microcomputer or the like. Then, the clutch control signal output from the electronic control unit 20 is input to the electromagnetic powder type clutch 2 and the shift control signal and the line pressure control signal are input to the hydraulic control circuit 17 of the continuously variable transmission 4 to perform each control operation. Has become. 2, the electromagnetic clutch control system of the control unit 20 will be mainly described. First, the primary pulley rotation speeds Np of the sensors 21, 22, and 29,
The signals of the secondary pulley rotation speed Ns and the throttle opening θ are input to the shift speed control unit 30, and control signals corresponding to the shift speed di / dt are output. Further, the signals of the engine speed Ne, the throttle opening θ, and the actual gear ratio i (Ns / Np) of the sensor 19 are input to the line pressure control unit 31, and output a control signal corresponding to the target line pressure. These control signals are input to the continuously variable transmission 4 to control the line pressure to a predetermined value and to perform the shift control. The electromagnetic clutch control system includes a reverse excitation mode determination unit 32 to which the signals of the engine speed Ne and the travel range of R, D, and Ds of the shift position sensor 26 are input. For example, when Ne <300 rpm, or when parking ( In the case of the P) and neutral (N) ranges, the mode is determined to be the reverse excitation mode, and the output determination unit 33 supplies a small current in a direction opposite to the normal direction. Then, the electromagnetic powder type clutch 2 is completely released except for the residual magnetism. Further, it has an energization mode determination unit 34 to which a determination output signal of the reverse excitation mode determination unit 32, a stepping signal of the accelerator switch 28, and a vehicle speed V signal of the secondary pulley rotation speed sensor 22 are input, and determines a traveling state such as starting. Then, the determination signal is input to each of the current setting units 35, 36, and 37 in the start mode, the drag mode, and the direct connection mode. The start mode current setting unit 35 sets the start characteristics individually in relation to the engine speed Ne and the like in the case of normal start or start using the air conditioner and choke. Then, the starting characteristics are corrected based on the travel ranges of the throttle opening θ and the vehicle speeds V, R, D, and Ds, and the clutch current is set. The drag mode current setting unit 36 determines a small drag current when the accelerator is released at a low vehicle speed in each range of R, D, and Ds,
A drag torque is generated in the electromagnetic powder type clutch 2 so that the belt,
The play of the drive system is reduced, and the vehicle starts smoothly. Further, in this mode, the current is set to zero current until immediately before the vehicle stops after the clutch in the D range is released, and the ellipticity is secured. The direct-coupling mode current setting unit 37 determines the direct-coupling current based on the relationship between the vehicle speed V and the throttle opening θ in each of the R, D, and Ds ranges, completely engages the electromagnetic powder type clutch 2, and saves power in the engaged state. I do. The output signals of the current setting units 35, 36, and 37 are input to the output determination unit 33, and the clutch current is determined in accordance with the instruction. The map of each mode is as shown in FIG. An embodiment of the start control in the electromagnetic clutch control system will be described with reference to FIG. The start mode current setting unit 35 determines the energization mode, the engine speed Ne, the throttle opening θ, the vehicle speed V, the running range R,
A start mode determination unit 40 that receives the signals D and Ds to determine a start mode is provided. Based on the determination result, a current setting unit 41 determines a clutch current Ic and outputs the clutch current Ic from an output unit 42. The current setting unit 41 determines the clutch current Ic in proportion to the engine speed Ne, and changes the stall speed by the correction value C to perform variable stall control. Ic = f (Ni), Ni = Ne · (1 + C) In addition, after the start of the variable stall control, there is provided an acceleration calculating unit 43 into which the engine speed Ne is inputted, and the acceleration α is calculated as the engine speed per unit time. Α = (Ne
n)-(Nen-1). And this acceleration α
Is input to the correction value setting unit 44 to calculate the correction value C according to Cn = Cn−1 + kα. The correction value C is input to the current setting unit 41 and calculated. Further, when the accelerator is released, the throttle opening degree detection section 45 and the throttle opening degree detection section to which the throttle opening degree θ is input.
When the closing speed of the throttle opening θ is equal to or more than a predetermined value and the throttle opening θ is equal to or less than a predetermined value, the transient control unit 47 determines the transient control. Then, the correction value setting unit 48
, A small correction value C ′ (0 ≦ C ′ ≦ Climit) is set. Next, the operation of the control device thus configured will be described with reference to the flowcharts of FIGS. 5 (a) and (b) and the starting characteristics of FIG. First, when the accelerator is released in step S4 of the flowchart, the drag mode is set, and the drag current Id is set.
And the clutch 2 is stopped or coasting with the clutch 2 released. Further, when the vehicle speed V reaches the set vehicle speed V ₃ or V ₄ of FIG. 3, the clutch 2 switched to the clutch direct connection mode is engaged by the step S3. On the other hand, when the shift position is in the D, Ds or R range,
If the accelerator depression is less than V ₃ or V _4, it is determined that the start mode start mode determination unit 40 proceeds to subsequent step S5. Thus, the acceleration α of the engine speed is calculated by the acceleration calculation unit 43, and the clutch current Ic is set by the current setting unit 41 based on the correction value C based on this. Therefore, the clutch current Ic increases by variable stall control while shifting from the characteristic of a small increase rate of C = 0 as shown in FIG. 6 to the characteristic of a large increase rate of C = Climit as the engine speed increases, A corresponding torque is generated. When returning the accelerator at time t ₁ in such starting process, it is of being detected by the detection unit 45 and 46, illustrate this effect in the flowchart of FIG. 5 (b). First, it compares the current throttle opening theta ₁ and the previous throttle opening theta _2, obtains the change amount Δθ when θ _{1 <θ 2.} If variation [Delta] [theta] is '[Delta] [theta] ≧ theta with respect to' a predetermined value theta, further when "to theta ₁ ≦ theta compared to" throttle opening theta ₁ and a predetermined throttle opening theta, transient control of the throttle suddenly closed Is determined. And this throttle opening θ
To prepare for the next store ₁ in place of the previous throttle opening theta _2. In the case of this transient control, by setting a small correction value C ', the clutch current Ic is temporarily set to C = C as shown in FIG.
The characteristic decreases to C ', and the state of the increase rate returns to the original state by the variable stall control again according to the acceleration α of the engine speed. Thus, the clutch torque is temporarily reduced in the case of the accelerator return, and the transmission of the wheel side driving force is absorbed by the slip at this time. As mentioned above, although one Example of this invention was described, it is not limited to this. Further, the present invention can be applied to an automatic clutch other than the electromagnetic clutch.

【The invention's effect】

As described above, according to the present invention, the shock when the accelerator is depressed at the time of starting is absorbed, so that the riding comfort is improved. In the variable stall control, the correction value is reduced to reduce the clutch torque, so that the transient control can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a control device of the present invention, FIG. 2 is a block diagram of an entire electronic control system, FIG. 3 is a map diagram of each mode, and FIG. Figure, fifth
Figures (a) and (b) are flowcharts for explaining the operation,
6 (a), 6 (b) and 6 (c) are characteristic diagrams of accelerator return. 2 ... Electromagnetic powder clutch, 20 ... Electronic control unit, 35
…… Start mode current setting section, 40 …… Start mode determination section
41: Current setting section, 45: Throttle sudden closing detection section, 46:
... Throttle opening detector, 47 ... Transient control determiner, 48 ...
... Correction value setting section.

Claims (2)

(57) [Claims] In a start control system for generating a clutch torque proportional to the engine speed when the accelerator pedal is depressed in a low speed range, when the throttle is rapidly closed and the throttle opening is equal to or less than a predetermined value, the clutch torque is temporarily reduced. A control device for an automatic clutch for a vehicle that controls so as to be lowered. 2. The automatic clutch control device for a vehicle according to claim 1, wherein the correction value of the variable stall control is temporarily reduced when the throttle is rapidly closed and the throttle opening is equal to or less than a predetermined value.