JPH0473005B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a control device for an automatic clutch provided between an engine and a transmission in a vehicle such as an automobile. The present invention relates to a clutch control device for a vehicle equipped with an automatic clutch, which performs emergency clutch disengagement control to prevent this.

(Prior Art) In a vehicle, a clutch is used as a device that connects and disconnects engine power to drive wheels. On the other hand, recent advances in technology have led to the development of automatic control systems that automatically perform this clutch operation along with transmission operation. Things started to be used.

Among these automatic control devices, the automatic clutch device is configured to control the engaged state of the clutch by driving a clutch actuator having a cylinder and a piston that operate a clutch operating body,
An electronic control device consisting of a microcomputer drives the clutch actuator according to vehicle operating conditions such as engine speed and accelerator pedal position signals.

To explain this automatic clutch device in more detail,
The electronic control device is configured such that the electronic control device constantly calculates the engagement amount of the clutch based on the engine rotation speed signal and the accelerator pedal position signal and determines the operating position of the clutch actuator. When the vehicle starts, an electronic control unit determines the clutch operating position based on the amount of depression of the accelerator pedal and the engine speed, which change moment by moment. Then, the electronic control device drives and controls the clutch actuator to gradually move the clutch operating body from the disengaged position, through the half-clutch position, and to the engaged position, thereby smoothly starting the vehicle. Such a clutch drive control operation is performed not only when the vehicle is started, but also when the transmission gear is changed while the vehicle is running.

In such an automatic clutch device, since the wheels do not rotate when the vehicle is stopped, the clutch is disengaged to prevent the engine from stopping and to ensure idling rotation. Also, when the vehicle is running at a very low speed, the electronic control unit appropriately controls the clutch to be in a half-clutch state to prevent the vehicle from slipping due to insufficient engine torque. In order to prevent the engine from suddenly stopping when the brake pedal is depressed, this clutch control device disengages the clutch when it detects that the engine speed or vehicle speed has fallen below a predetermined set value.

In addition, instead of the above-mentioned device that controls clutch disengagement based on engine speed or vehicle speed, a proposal is made to detect the deceleration of the input shaft of the transmission and disengage the clutch when the input shaft decelerates rapidly. JP-A-60-8553) has been published.
In other words, in this proposal, as shown in Figure 9,
The rotational speed of the engine 101 (or the input shaft 105 which is transmitted to the synchronous mesh transmission 103 via the clutch 102 and measured by the sensor 104)
The characteristic is that the input shaft rotational speed) gradually decelerates after the brake pedal is depressed by increasing its deceleration (in other words, the amount by which the input shaft rotational speed decreases per unit time), and the state when the brake pedal is depressed is Since the deceleration is reflected in the speed, the clutch is disengaged if the deceleration exceeds a set value. Note that the rotational driving force of the transmission 103 is transmitted to the drive wheels 108 of the vehicle via its output shaft 106 and differential gear 107. Therefore, when the driver applies sudden braking, the input shaft 105 reaches the limit deceleration faster than when applying normal braking, so the clutch is disengaged early to prevent the engine from stopping unexpectedly. It is something that can be done.

(Problems to be Solved by the Invention) The former of the two conventional devices described above works effectively when deceleration is gradual, but when deceleration is rapid, the clutch cannot be disengaged in time. The engine may stop. That is, if you release the accelerator and press the brake pedal relatively slowly, the engine will not stop even if you release the clutch after detecting that the engine speed has fallen to the set value (500 rpm).
However, when the brake pedal is suddenly depressed, or when the tires slip on the snowy surface and the wheels become locked, the brakes are applied quickly and the engine speed has dropped to the set value. Even if the electronic control unit starts to disengage the clutch after detecting it, it takes a long time to detect a drop in engine speed or vehicle speed and then for the clutch to actually operate. In fact, there was a problem in that the engine speed suddenly dropped and the engine stopped before the clutch could operate.

In addition, in the latter conventional device, as shown in Fig. 10, the degree of decrease in input shaft rotational speed per unit time (t ₀ ) when the brake is depressed is detected, and if the degree of decrease is greater than a set value, , the clutch is urgently disengaged to prevent the engine from stopping. In this way, on a general road (curve a in the figure), the degree of decrease (Ra) is less than the set value, that is, the input shaft rotation speed gradually decreases, so
The clutch will break. This prevents the engine from stopping unexpectedly, since the input shaft rotational speed does not drop to nearly zero during the period from when the clutch starts operating until the clutch actually disengages, but it is possible to prevent the engine from stopping unexpectedly on roads with little friction against the tires, such as on snowy roads. In curve b) of the figure, the tires easily lock up, and the input shaft rotational speed drops rapidly to the point where it almost stops rotating, so that the degree of reduction (Rb) exceeds the set value. For this reason, the time it takes for the input shaft to stop rotating is faster than for the clutch to be completely disengaged, so when the clutch disengages, the engine rotation stops and stalling cannot be prevented. It has the following drawback.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control method that prevents the engine from suddenly stopping even if the brakes of a vehicle are rapidly applied.

Another object of the present invention is to detect the brake braking force when the brake pedal is depressed in a place where the coefficient of friction of the tire against the road surface is small, such as a snowy road, and to detect the clutch from a combination of this braking force and the separately detected engine speed. To provide a clutch control device for a vehicle equipped with an automatic clutch, which prevents an engine from stopping by emergency disconnection.

(Means for Solving the Problems) According to the present invention, in a clutch control device for a vehicle equipped with an automatic clutch that controls disengagement of a clutch connecting an engine and a transmission when the brake is applied, a control system that detects the braking force of the brake is provided. a power detection means, a rotation speed detection means for detecting the engine rotation speed, a setting means for setting the engine rotation speed at which the clutch is disengaged in accordance with the braking force, and a braking force detected based on the setting means. A clutch control device for a vehicle equipped with an automatic clutch is provided, characterized in that it has a clutch drive means for disengaging the clutch when the corresponding engine speed is lower than a set value.

(Function) As described above, in the present invention, it is possible to detect that the engine rotation speed or vehicle speed has fallen below a predetermined set value, or to detect that the degree of decrease in the input shaft rotation speed has exceeded a predetermined set value. Instead of conventional devices that control the clutch disengagement by detecting the amount or rate of increase in braking force, the system automatically disengages the clutch if the amount or rate of increase in braking force exceeds a set value. This prevents the engine from stopping unexpectedly, so even if the brakes are applied to the vehicle, the engine will never stop unexpectedly.

(Embodiment) Fig. 1 is a block diagram of an embodiment for realizing the present invention. In the figure, 1 is a gasoline engine, which includes a throttle valve for controlling the amount of intake gas (air or mixture). It is equipped with a flywheel 1a. Note that this engine is not limited to a gasoline engine, but may also be a diesel engine. Reference numeral 2 denotes a clutch body, which is constructed of a well-known dry type single plate clutch and has a release lever 2a. 3 is a hydraulically operated clutch actuator having a cylinder and a piston, and includes a plurality of electromagnetic valves for controlling the clutch actuator. In order to control the amount of engagement of the clutch body 2, a piston is moved by controlling the opening and closing of these electromagnetic valves, and the piston rod 3a drives the release lever 2a. 4 is a hydraulic mechanism. 5 is a transmission actuator, which includes an actuator in the shift direction and an actuator in the select direction.
Reference numeral 6 denotes a parallel shaft gear type transmission, which is driven by a transmission actuator 5 to perform speed change operations, and includes an input shaft 6a connected to the clutch 2, and an output shaft (drive shaft) 6b. There is. 7 is a select lever which is operated by the driver and selects "N" range (neutral position), "D" range (automatic shift), "1" range (1st speed), "2" range (2nd speed), " 3” range (1st, 2nd, 3rd speed automatic shifting) and “R” range (reverse) can be selected by the lever position, and the position signal of the select lever 7 is sent to the electronic control device described later. Read. The select lever 7 is generally of the type that switches the lever in the front and back direction as shown in the figure, but a type that moves the lever in an "H" shape may also be used. Reference numeral 10 denotes an engine rotation sensor, which detects the rotation speed of the engine 1 from, for example, the frequency of the number of teeth per unit time at which teeth notched around the flywheel 1a pass in front of a tooth detection section. Reference numeral 9 denotes an electronic control device composed of a microcomputer, which includes a processor 9a that performs arithmetic processing, a control program for controlling the transmission 6, a control program for controlling the clutch 5 according to the present invention, etc. A read-only memory (ROM) 9b that stores data such as control programs and control maps, and an output port 9
c, an input port 9d, a random access memory (RAM) 9e that stores calculation results, etc., and an address/data bus (BUS) 9 that connects these.
It is composed of f. The output port 9c is connected to the clutch actuator 3, the hydraulic mechanism 4, and the transmission actuator 5, and outputs a drive signal for driving these.

On the other hand, the input port 9d is connected to an engine rotation sensor 10 and a brake pedal to be described later, and receives a detection signal thereof. 11 is an accelerator pedal, and the amount of depression thereof is read into the electronic control device 9. A brake pedal 12 operates a brake air valve 12a for sending brake operating air pressure to the brake according to the amount of depression of the brake pedal 12.

Next, with reference to FIG. 2, the principle of the present invention will be explained by considering the relationship between brake operating force and brake braking force. Figure 2 shows the brake operating air pressure P determined by the amount of depression of the brake pedal 12.
2 is a graph plotting the brake braking coefficient g against (Kg/cm ² ) separately for when a large amount of cargo is loaded (line c) and when there is no cargo (straight line d).
Note that the point Pl on the horizontal axis indicates the brake operating air pressure value at which the wheels lock on roads where the coefficient of friction between the tires and the road surface is small, such as on snowy roads.

As can be seen from Figure 2, the brake braking coefficient g
That is, the braking force can be divided into three levels, for example, "normal braking,""slightly stronger braking," and "stronger braking." Therefore, if the driver depresses the brake pedal 12 quickly and deeply, the brake air valve 12a is wide open, and a large braking force is applied to the brake (not shown), causing the brake to enter a "strong braking" state.
Since "engine stop" does not occur, even if the clutch is immediately disengaged, there will be no problem whether there is a large load or no load. However, with slightly stronger braking or especially normal braking, if the clutch is set to disengage to prevent the engine from stopping unexpectedly on roads where the coefficient of friction between the tires and the road surface is low, then each time you step on the brake while driving on a regular road, This is dangerous as the clutch may break. Therefore, the clutch is controlled so that the emergency disconnection is performed based on a combination of the braking force and the engine speed.

That is, as is clear from FIG. 2, the brake braking force is proportional to the amount of depression of the brake pedal 12, that is, the brake operating air pressure P.
As shown in FIG. 3, in the present invention, a plurality (four in this case) of air pressure switches SW1 to SW4 each having a different detection pressure are provided on the brake side of the brake air valve 12a. Additionally, an engine rotation sensor 10 is separately provided to the engine 1,
The clutch 2 is controlled for emergency disconnection by combining the detected rotational speed of the engine 1 with the sense output from the pressure switch. In this case, as shown in FIG.
The pressure at which SW4 operates, that is, the pressure at which each pressure switch turns off, is the air pressure value Pl at which the wheels lock when running on a low-friction road.
and set it as follows.

SW1: 0.3 (Kg/cm ² ) SW2: 1.2 (Kg/cm ² ) SW3: 2.3 (Kg/cm ² ) SW4: 4.0 (Kg/cm ² ) The set pressure of this air pressure switch SW4 (4.0Kg/cm 2 ) cm ² ) is the operating pressure at which a sufficient braking force can be obtained, as can be seen from FIG.

Next, this clutch disengagement control will be explained with reference to the flowchart of FIG.

(1) When the driver depresses the brake pedal 12 shown in FIG. 1 to stop the vehicle, the electronic control device 9 detects this based on a signal from, for example, the air pressure switch SW1, and the electronic control device 9 The execution of the job shown in the flowchart of FIG. 5 begins. Then, in step S1, it is determined whether the air pressure switch SW4 has been operated.

When air pressure switch SW4 is turned on, the signal is sent to input port 9d, BUS9f.
It is input to the CPU 9a via. In this way, when the brake pedal 12 is depressed considerably and the driver applies a "strong brake" to the vehicle,
Since there is no problem in immediately disengaging the clutch 2, the CPU 9a moves to step S2, and the clutch actuator 3 sends a clutch release signal through the output port 9c to release the clutch 2.

(2) At step S1, air pressure switch SW
If the air pressure switch SW3 is not operating, the process moves to step S3, where it is determined whether the next air pressure switch SW3 is operating. This step
In step S3, if the air pressure switch SW3 is operating, it is determined that the brake pedal 12 has been depressed with a fairly large force and the vehicle is being brought to a sudden stop with "slightly strong braking", and step S4 is performed. Move to. the steps here
In S4, the rotation speed of the engine 1 is compared with a set value A. If the rotation speed is lower than the set value A, the load on the engine 1 due to braking the vehicle will increase rapidly, and if the load continues, the engine 1 will stop. After the judgment is made, the electronic control unit 9 immediately issues a command to the clutch actuator 3 to take emergency clutch disengagement measures, and the clutch 2 is rapidly disengaged (step
S2).

In step S4, if the rotational speed of the engine 1 is not lower than the set value A, it is determined that the load on the engine 1 due to braking has not increased significantly, and the clutch 2 is not disengaged and the electronic The operation of the control device 9 exits the flow shown in FIG. 5 as it is. (Step S4).

(3) At step S3, press the air pressure switch SW.
If the air pressure switch SW2 is not operating, the process jumps to step S5, where it is determined whether the next air pressure switch SW2 is operating. This step
In S5, if air pressure switch SW2 is activated, the brake pedal 1 will be pressed with considerable force.
2 is depressed, and it is determined that the vehicle is about to be brought to a sudden stop in the "normal brake" state, and the process moves to step S6. In step S6 here, the rotation speed of the engine 1 is compared with a set value B, which is a slightly lower value than the set value A. If the rotation speed is lower than set value B, the load on engine 1 due to braking the vehicle will increase rapidly, and if the load continues, engine 1 will stop. As soon as the judgment is made, a command is issued from the electronic control unit 9 to the clutch actuator 3 to take emergency clutch disengagement measures, and the clutch 2 is rapidly disengaged (step S2).

In step S6, if the rotation speed of the engine 1 is not lower than the set value B, it is determined that the load on the engine 1 due to braking has not increased significantly, and the clutch 2 is not disengaged and the electronic The operation of the control device 9 exits the flow shown in FIG. 5 as it is. (Step S6).

(4) At step S5, press the air pressure switch SW.
If the air pressure switch SW1 is not operating, the process jumps to step S7, where it is determined whether the next air pressure switch SW1 is operating. This step
In S7, if air pressure switch SW1 is activated, brake pedal 12 is pressed with normal force.
It is determined that the brake is being depressed and the vehicle is trying to stop with a "weak brake" condition, and the process moves to step S8. In step S8 here, the rotation speed of the engine 1 is compared with a set value C, which is a lower value than the set value B. If the rotation speed is lower than the set value C, the load on the engine 1 due to braking the vehicle will increase rapidly, and if the load continues, the engine 1 will stop. As a result, the electronic control device 9 immediately releases the clutch actuator 3.
A command is issued to take emergency clutch disengagement measures, and clutch 2 is rapidly disengaged (step S2).

In step S8, if the rotation speed of the engine 1 is not lower than the set value C, it is determined that the load on the engine 1 due to braking has not increased significantly, and the clutch 2 is not disengaged and the electronic The operation of the control device 9 exits the flow shown in FIG. (Step S8).

As a modification of the embodiments of the invention described above, the invention can also be practiced by providing a single switch and an air pressure sensor instead of a plurality of air pressure switches.

That is, as shown in FIG. 6, an air pressure switch SW with a set operating pressure of 0.3 kg/cm ² and an air pressure sensor S are provided on the brake side of the brake air valve 12a. This pressure sensor S detects the brake operating air pressure P using a voltage value V, as shown in FIG.

The operation of this modification will be explained below with reference to the flowchart of FIG.

The brake pedal 12 shown in Fig. 6 is depressed and the air pressure switch SW is turned on (step P1).
Then, the CPU 9a activates the air pressure sensor S to detect the air pressure and reads it into the RAM 9e (step
P2). The CPU 9a also has an engine rotation sensor 10
Detect the engine rotation speed emitted from the
Read into RAM9e (step P3). Next, the CPU
9a searches the map (brake operating air pressure P and engine speed) stored in the ROM 9b, and stores the data obtained from the read brake operating air pressure and engine speed in the emergency clutch disengagement area in the map. Check if it belongs (step
P4, step P5). If this data is within the range, the CPU 9a sends a clutch release signal to the clutch actuator 3 via the output port 9c to release the clutch 2 (step P6). step
At P5, if the read data is not in this area, the clutch 2 is not released and the operation of the electronic control unit 9 exits from the flow shown in FIG.

In the several embodiments described above, the brakes are operated by air, but this can be done by providing a pressure switch or a pressure sensor as described above in the hydraulic brake cylinder operated by the brake pedal. Those skilled in the art should also be able to easily realize clutch control similar to that of the embodiment, and the present invention encompasses these obvious modifications.

(Effects of the Invention) As explained above, according to the present invention, the brake braking force is detected when the brake is depressed, and the clutch is controlled for emergency disengagement based on the combination with the separately detected engine speed. Therefore, it is possible to prevent the engine from stopping when the brake is depressed not only on ordinary roads but also on low μ roads such as snowy roads. Therefore, the effect is that the transmission using the automatic clutch becomes more complete.

[Brief explanation of the drawing]

Figure 1 is a system configuration diagram showing an embodiment of the present invention, Figure 2 is a characteristic diagram showing the relationship between brake pedal depression air pressure and brake braking force, and Figure 3 is a diagram showing the relationship between brake pedal depression air pressure and brake braking force. Fig. 1 is a partial schematic diagram of the system showing the air pressure switch for detection, Fig. 4 is an explanatory diagram similar to Fig. 2 to explain the set pressure of the air pressure switch, and Fig. 5 is the same as in this book. 6 is a partial schematic diagram similar to FIG. 3 showing an air pressure sensor added to detect the air pressure of the brake air valve, and FIG. 7 is a process flow chart of an embodiment of the invention. A characteristic diagram showing the output characteristics, FIG. 8 is a processing flowchart of another embodiment of the present invention, and FIG. 9 is a diagram showing a conventional method for controlling clutch disengagement by detecting the deceleration of the input shaft. FIG. 10 is a schematic diagram showing the transmission, and is a timing chart showing the deceleration of the conventional input shaft shown in FIG. 9 in relation to the engagement and disengagement of the brake and clutch. 1... Engine, 2... Clutch, 3... Clutch actuator, 6... Transmission, 10... Engine rotation sensor, 12... Brake pedal, 1
2a...Brake air valve, SW, SW1~SW
4...Air pressure switch, S...Air pressure sensor.

Claims (1)

[Scope of Claims] 1. A clutch control device for a vehicle equipped with an automatic clutch that controls disengagement of a clutch that connects an engine and a transmission when a brake is applied, comprising a braking force detection means for detecting the operating force of the brake, and a rotational speed of the engine. a setting means for setting the engine rotation speed at which the clutch is disengaged in accordance with the braking force; and a setting means for setting the engine rotation speed corresponding to the braking force detected based on the setting means. 1. A clutch control device for a vehicle equipped with an automatic clutch, comprising a clutch drive means for disengaging the clutch when the clutch is lower than the clutch. 2. The clutch control device for a vehicle equipped with an automatic clutch according to claim 1, wherein the braking force of the brake is detected by the pressure of brake operating fluid.