RU2426019C2 - Method of control over automotive automatic clutch disengagement - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: on revealing vehicle downsliding and/or accelerator zero displacement engine rpm in first gear is reduced unless clutch 3 is disengaged. Engine rpm in first gear is reduced to below rpm whereat engine idling rpm regulator 20 injects certain amount of fuel into engine 2 that corresponds to positive torque equal to current braking negative torque. This makes total engine output torque equal approximately to zero. Clutch automatic control unit incorporates memory containing machine-readable program for control unit to disengage vehicle automatic clutch 3.

EFFECT: eliminating acceleration in engine braking with disengaged clutch.

5 cl, 2 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a method for controlling an automatic disk clutch mounted on a motor vehicle according to the preamble of claim 1, for transmitting the traction of an internal combustion engine of a transmission.

The invention also relates to a computer-readable storage medium comprising computer-readable program code for implementing said method.

State of the art

Heavy-duty vehicles are increasingly equipped with automatic transmissions such as automatic mechanical transmissions (AMT), which became possible with the development of microcomputer technology, which allowed using the control computer and several controls, such as servomotors, to precisely control the engine speed, turn on and off the automatic the clutch of the engine and gearbox and the clutch elements of the gearbox relative to each other and thus always both Sintered for smooth gear shifting at the correct speed.

AMT typically has an input shaft, an intermediate shaft with at least one gear engaged with a gear on the input shaft, and a secondary shaft with gears that mesh with the gears on the intermediate shaft. The secondary shaft is further connected to the output shaft, which, for example, is connected to the drive wheels by means of, for example, a cardan shaft. Each pair of gears has a gear ratio different from the other pair of gears of the gearbox. Different pairs of gears transmit engine torque to the drive wheels, whereby various gear ratios are obtained.

The development of computer technology has also impacted the electronic control and feedback systems of the automobile engine, making them more accurate, increasing their speed and improving their compatibility with existing engines and operating conditions. The entire process of fuel combustion can be precisely controlled in accordance with any working environment. The gas regulator (accelerator) of the car (for example, the accelerator pedal or "gas"), which mainly regulates the fuel supply to the engine, controls the car engine through a system of electrical wires and electronic signals. For this, the accelerator is equipped with sensors that determine its position, in other words, what is required to open the throttle.

When a car with automatic clutch and transmission moves down the hill with the accelerator pedal not pressed by the driver and, for example, low gear (with a high gear ratio) is engaged, the engine speed will be limited to a value close to the engine idle speed if the engine develops a certain braking force sufficient at least to slightly slow down the vehicle so that subsequently the engine speed approaches the engine idle speed, which is usually disengages the clutch. If the clutch is deactivated in this situation without applying the service brake or only when the service brake is slightly applied, the vehicle will suddenly accelerate due to the weakening of the braking force developed by the engine. In this situation, only with a service brake slightly applied does a large part of the braking force develop by the engine, which leads to a sharp acceleration when the engine engages with the transmission and drive wheels of the vehicle. In this case, the driver is likely to feel discomfort, especially if the clutch disengagement is initiated by lightly pressing the brake pedal.

The present invention is based on the task of eliminating the possible occurrence of a situation in which a sharp acceleration of the vehicle occurs due to disengagement of the clutch or even disengagement of the clutch, initiated by lightly pressing the brake pedal.

Summary of the invention

The present invention provides a method for controlling automatic vehicle clutch disengagement, in which the main clutch function is to transmit the traction of an internal combustion engine mounted on the vehicle to the input shaft of the transmission mounted on the vehicle, and the engine speed is controlled by an accelerator. The method is characterized in that upon detecting vehicle movement in a downward slope and zero accelerator bias, a reduction in the engine speed limit in first gear is initiated, at which the clutch is disengaged.

An advantage of the method proposed in the invention is that the clutch is deactivated later than usual, thereby activating the engine idle speed controller, and the engine generates a positive output torque that attenuates the effect of torque loss due to engine braking at which the clutch is off. Due to this, the discomfort felt by the driver is reduced.

In one embodiment of the method of the invention, the aforementioned actuation of the engine idle speed controller is described. In this embodiment, said first engine speed limit is reduced to a level below that at which the engine idle speed controller mounted on the vehicle is driven and starts to inject fuel into the internal combustion engine. This reduces the inconvenience of losing torque due to engine braking when the clutch is disengaged.

In another embodiment of the method, said limit of the engine speed in the first gear is reduced to the frequency at which the engine speed controller idling injects the amount of fuel corresponding to the positive engine torque, which is equal to the current braking negative engine moment, due to bringing the total engine output torque to approximately zero. This completely eliminates the effect of vehicle acceleration due to loss of torque due to engine braking when the clutch is disengaged.

In one of the additional embodiments of the method proposed in the invention, said reduction of the engine speed limit in first gear is also triggered by the additional detection of a slight pressing or absence of pressing the vehicle’s service brake pedal. This ensures that the vehicle does not accelerate when the driver presses the brake pedal slightly. In a further improved embodiment, said light pressing corresponds to an offset of said service brake pedal by up to 25% of the total possible offset.

Brief Description of the Drawings

Further, the present invention is described in more detail with reference to the accompanying drawings, in which preferred embodiments of the invention are shown as examples: FIG. 1 schematically shows a preferred embodiment of a vehicle configuration according to the invention,

figure 2 schematically shows a computer device used in one embodiment of the invention.

Description of the invention

In one embodiment, the vehicle 1 has an internal combustion engine 2, for example a diesel engine with a crankshaft 21, which is connected to a dry single-plate clutch 3, which is placed in the clutch housing 22. The crankshaft 21 is fixedly connected to an input shaft (not shown), which is rotatably mounted in the crankcase 23 of the gearbox 4. In the crankcase 23 of the gearbox, the secondary shaft and the intermediate shaft not shown are also shown.

To control various piston cylinders with a pneumatic drive, a transmission control unit 16 is provided, including various gear ratios between the input shaft and the output shaft 5 of the transmission according to programmable logic circuits. The transmission control unit 16 also serves to control the clutch 3 in order to engage / disengage the clutch of the engine 2 and the transmission 4, for example, when a gear shift occurs or the vehicle moves at a speed lower than the engine idle speed. The output shaft goes into the driveshaft and connects the transmission to the driven rear wheels 6.

The decision-making process on when to shift gears is known in the art and will not be described in detail in the present invention. As is known from the prior art, when deciding to disengage clutch 3, parameters such as engine speed, accelerator pedal position, input shaft speed and engine speed deceleration can be taken into account.

The engine 2 is equipped with an idle speed controller 20, known from the prior art, and accordingly there is an engine idle speed below which the idle speed controller 20 does not allow the engine speed to fall. The idle speed controller 20 is preferably located in the engine control unit 12. The engine idle speed controller can be implemented by the program code of the engine control unit 12, designed to perform the function of regulating the engine idle speed. If the transmission control unit 16 detects a deceleration of the engine speed, as a result of which the engine speed decreases to a level close to the engine idle speed, the transmission control unit 16 can initiate a clutch disengagement to protect the engine 2 from stopping.

Using the accelerator 13 (preferably the accelerator pedal) in a known manner to regulate the torque generated by the engine 2. Using the angular sensor determine the position of the accelerator, which registers the control unit 14 of the accelerator.

The vehicle 1 also has a service brake system, including service brake drives 8 located on non-driven front wheels 7 and driven wheels 6, a service brake control means 9 (preferably a brake pedal) and a brake control unit 10. The function of the service brake system is known in the art.

The various control units with which the vehicle is equipped are preferably connected in a known manner by means of a data bus system 15 mounted on the vehicle. Thus, the transmission control unit 16 can be designed for indirect control of fuel injection (i.e. engine speed and torque) depending on the position of the accelerator and direct control of the fuel supply to the pneumatic piston cylinders of the clutch actuator 17, whereby, for example, said clutch 3.

When the gear lever 24 is set to automatic gear selection, the gear selection and shift decisions are made automatically by the transmission control unit 16 based on certain measured and (or) calculated parameters, such as vehicle speed, engine speed, vehicle speed change, the speed of changing the engine speed, the position of the accelerator, the speed of changing the position of the accelerator, the brake system of the vehicle, t kuschee included gear ratio, road inclination and the like, which are known in the art. The slope of the road can be determined in a known manner, for example using a piezoelectric slope sensor. This sensor is preferably located in the transmission control unit 16.

In one embodiment of the invention, the transmission control unit 16 is programmed to recognize the specific state of the vehicle as described above by detecting: the vehicle is moving in a downward slope and zero accelerator bias.

Upon detection of the aforementioned certain state, the transmission control unit 16 is programmed to reduce the engine speed limit in the first gear at which, according to the prior art, the clutch 3 would be turned off. Thus, according to the invention, the disengagement of the clutch 3 during said state will be delayed until the engine reaches a lower speed. When the engine speed drops to a level close to the engine idle speed, the engine idle speed controller 20 is activated and starts injecting a certain amount of fuel into the engine 2 to try to stop further deceleration of the engine speed. As a result of fuel injection, the engine 2 generates a certain positive torque that balances the negative torque at the output of the engine 2 due to various losses in the engine, for example, due to friction between various engine parts and various auxiliary loads, such as a generator and an air compressor.

In one of the preferred embodiments of the invention, the transmission control unit 16 is programmed to detect and calculate the moment when the positive output torque (controlled by the engine idle speed controller 20) of the engine 2 becomes equal to the negative output engine torque. When the positive and negative engine torques become approximately equal, the transmission control unit 16 is programmed to initiate the disengagement of the clutch 3. Since the net torque at the output of the engine 2 is equal to zero, when the clutch of the engine 2 with the transmission 4 and the driving wheels 6 of the vehicle is turned off, the acceleration does not change / deceleration of the vehicle 1.

The positive torque at the engine output can be calculated based on the known amount of fuel injected into the engine in a known manner. Negative torque at the engine output can be estimated in various ways known in the art. Alternatively, you can use some kind of torque sensor on the output shaft of the engine. If the torque sensor determines that the torque is zero, the positive and negative engine torques are equal.

In one preferred embodiment of the invention, said engine speed limit in first gear is reduced to a level below the engine idle speed. For example, in the case of a heavy-duty truck, this means that the engine speed limit in first gear is reduced, for example, from 650 rpm to 600 rpm. The engine speed limit according to this embodiment may be a specific value previously stored in the transmission control unit 16.

In another preferred embodiment, the degree of reduction of said engine speed limit in first gear is determined as a function of at least the angle of said downward slope.

In a further preferred embodiment, the degree of reduction of said engine speed limit in first gear is further determined as a function of deceleration of the engine speed.

In another preferred embodiment of the invention, said function of reducing the engine speed limit in first gear is supplemented by a limitation on engine torque, according to which the drive to the drive wheels is turned off when the calculated net output torque exceeds a certain limit.

In one embodiment of the invention, said function of decreasing the engine speed limit in first gear is activated unless the vehicle’s service brake pedal 9 is depressed. Mentioned strong pressing may correspond to the displacement of the aforementioned brake pedal by more than 25% of the total possible displacement.

The function of reducing the limit of engine speed in first gear according to the invention can be used with high or low gear ratios engaged,

FIG. 2 shows a device 500 according to one embodiment of the invention, comprising a non-volatile memory 520, a processor 510, and a read and write memory 560. The memory 520 has a first area 530 in which a computer program for managing the device 500 is stored. The computer program for managing the device 500 stored in the memory area 530 may be an operating system.

The device 500 may be placed, for example, in a control unit, such as a transmission control unit 16. The data processing unit 510 may be, for example, a microcomputer.

The memory 520 also has a second region 540 in which the clutch release control program according to the invention is stored. In one alternative embodiment, the clutch control program is stored in a separate non-volatile storage medium (means) 550, such as, for example, a compact disk or a semiconductor memory with removable disks. The program may be stored in executable form or in compressed form.

When it is further indicated that the data processing unit 510 performs a specific function, it should be clear that the data processing unit 510 executes a specific part of the program stored in the memory 540 or a specific part of the program stored in the non-volatile recording medium 550.

Data processing unit 510 is designed to communicate with memory 550 via data bus 514. The data processing unit 510 is also designed to communicate with the memory 520 via the data bus 512. In addition, the data processing unit 510 is designed to communicate with the memory 560 via the data bus 511. The data processing unit 510 is also designed to communicate with the data port 590 by using the data bus 515.

The method of the present invention may be implemented by a data processing unit 510 that executes a program stored in memory 540 or a program stored in a non-volatile recording medium 550.

The invention should not be considered limited by the embodiments described above, and a number of additional options and improvements are contemplated within the scope of the following claims.

Claims (5)

1. A control method for disabling the automatic clutch (3) of a vehicle (1), in which the main function of the clutch (3) is to transmit the traction of an internal combustion engine (2) mounted on the vehicle to the input shaft of the transmission (4) also installed on the vehicle, and the engine speed is regulated by means of an accelerator (13), and upon the implementation of which a reduction of the engine speed limit in first gear is initiated, at which the clutch disengages (3), when it is detected the movement of the vehicle (1) in a downward slope and zero displacement of the accelerator (13), and the engine speed limit in first gear is reduced to the frequency at which the engine speed controller (20) idling injects a certain amount of fuel corresponding to the positive torque of the engine, which is equal to the current braking negative moment of the engine, due to which the total torque at the output of the engine (2) is approximately equal to zero. 2. The method according to claim 1, characterized in that the limit of the engine speed in first gear is reduced to a level below the frequency at which the speed controller (20) of the engine idling installed on the vehicle (1) is activated and starts to inject fuel to the internal combustion engine (2). 3. The method according to claim 1, characterized in that the reduction of the engine speed limit in the first gear is initiated only under the additional condition of detecting a slight depression or absence of pressing the pedal (9) of the vehicle’s service brake (1). 4. The method according to claim 3, characterized in that the light pressure corresponds to the displacement of the brake pedal (9) by up to 25% of the total possible displacement. 5. The control unit for turning off the automatic clutch of the vehicle, equipped with a memory containing a machine-readable program, the execution of which the control unit carries out the actions of the method according to claim 1.

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