DE102013210266A1 - Method for performing a clutch start - Google Patents

Abstract

A method and a clutch arrangement (30) for performing a clutch start are presented. In the method, a clutch (42) is closed by this valve (38) from a state in which it is kept open by a valve (38).

Description

The invention relates to a method for performing a clutch start and a clutch assembly for carrying out the method. In particular, the invention relates to a clutch assembly having a transmission by means of a fluid of the force introduced by a driver on a clutch actuating element to the clutch.

State of the art

The force introduced by a driver by actuating a clutch operating element can be transmitted in different ways. So it is known to do this by means of hydraulic transmission. The publication DE 198 56 297 A1 describes such a clutch assembly in which a hydraulic emergency control is provided for a arranged between an internal combustion engine and a transmission hydraulically actuated clutch. This hydraulic emergency control comprises a valve for controlling the clutch in the event of a failure of the electrical supply of the electrohydraulic clutch control. In addition, stalling of the internal combustion engine can be prevented in a vehicle standstill.

In motor vehicles, a distinction is made between different driving conditions. Sailing is a driving condition that is already known in hybrid vehicles, such as, for example, in a parallel hybrid with a separating clutch between the internal combustion engine and the electric drive machine. It has been found that sailing is also useful in conventional vehicles, especially in the context of rising fuel prices and the need to reduce emissions.

Sailing, also known as freewheeling, high speed free rolling, coasting, etc., opens the drivetrain and decouples the combustion engine and transmission. Due to the missing engine drag torque, the vehicle unrestrainedly rolls further than with overrun fuel cutoff in the highest gear. In addition, the engine may continue to idle, referred to as idle sailing. Finally, the engine can be switched off, which is called engine stoppage sailing. With a corresponding operating concept, the engine automatically restarts.

The powertrain of a motor vehicle means all components that transmit torque to the road. In a conventional powertrain, this includes the engine, the clutch with transmission, the drive shafts and the wheels.

The described idling sailing can be implemented without much additional effort, but only low fuel savings can be expected. The engine stop sailing shows in real driving vehicle and driver-dependent fuel savings potential of up to 10% in addition to a start-stop operation.

In hybrid vehicles, the necessary conditions for a sailing operation already exist. In a conventional vehicle, on the other hand, the starter system, electrical system, steering system, braking system and transmission must be adapted to the additional requirements.

Sail operation is possible with manual gearboxes, but this requires a cumbersome operating concept. In order to clarify this, a possible operating concept is presented below.

To initiate sailing, the driver must depress the clutch, place the transmission in neutral, and release the clutch. To restart the engine, the clutch must be pressed again. Then, in order to re-establish adhesion between the engine and the transmission, an appropriate speed gear of the vehicle must be engaged and the clutch released again. In support of the engine can perform a vehicle speed adapted and possibly gear-dependent speed increase, the speed at the transmission input and the engine speed are as similar as possible.

Disclosure of the invention

Against this background, a method according to claim 1 and a clutch arrangement according to claim 6 are presented. Embodiments result from the description and the dependent claims.

In the described method, in one embodiment, starting of an internal combustion engine of a motor vehicle from a sailing operation by closing a clutch between the internal combustion engine and a transmission, which cooperates with the rolling wheels of the motor vehicle. Accordingly, a drive train of the motor vehicle is closed, via which energy is exchanged between the internal combustion engine and the wheels of the motor vehicle. The closing of the valve held open by a valve is done by relieving just this valve.

As is known in the art, a clutch start reduces the starter cycles. Initial measurements show that the Implementation at speeds> 30 km / h is possible. In any case, there will be a lower speed threshold at which the clutch start is no longer comfortable. It is currently not clear where this will be. But by using the clutch start a reduction of the starter load by about 1/3 is possible.

Furthermore, the drive train can be kept open by means of the valve. This is a valve in the hydraulic line between the master and slave cylinder, as in 3 is shown.

The present invention realizes a clutch start with lower system cost. In this case, a system is used which is characterized by a valve in the clutch line. For this purpose, the following is discussed 2 directed.

The valve can be used to start the clutch after sailing. The clutch is slowly closed. This closing is effected by relieving the valve.

Keep open in this context means that the clutch and thus the drive train remain open, even if the clutch actuator is relieved. Relieved means that the driver is no longer initiated power on the clutch actuator or the clutch is no longer pressed or operated. This means that when the force applied to actuate the clutch is removed, the clutch still remains open. The clutch and thus the drive train are only then closed again when certain, specifiable events, such as, for example, an actuation of the accelerator pedal or the brake, if necessary, are detected in a predefinable period.

By fluid is meant gases and liquids, gases are used in pneumatic systems. Liquids are used in hydraulic systems.

The sailing operation is initiated, for example, when the clutch actuating element is actuated for a predeterminable period of time. The initiation can also take place if additionally a switch is actuated. It does not always have to be time-triggered. In particular, the sailing operation is initiated when no gear change takes place in the predeterminable period and / or no gas is given and / or a brake is not actuated.

The sailing operation can also be initiated by the manner of actuation of the clutch actuator.

To activate the sail operation, the driver goes to the clutch. If within a certain, predeterminable period no gear change takes place, which z. B. detected by neutral gear detection, no gas given and / or the brake is not actuated, the valve is actuated, usually closed, and thus kept the clutch open. The vehicle is then in sailing mode.

Leaving the sail condition may be initiated either by a re-clutching operation or as an extended simplification for the driver by accelerator operation or brake application. This has the consequence that the valve is opened again and the clutch is closed.

Once the vehicle is in sail mode, the driver can release the clutch pedal as the closed valve keeps the clutch open. The driver can stay in the current gear in sailing mode and does not have to switch to neutral before. This means a further increase in comfort. In the background, the engine control calculates a virtual engine speed as if the clutch were closed. If the vehicle speed falls below a prescribed minimum engine speed in the current gear, the sailing mode is automatically terminated. For this purpose, the valve is controlled and opens regulated again, so that the pressure on the clutch is reduced. The vehicle behaves like a conventional vehicle, the idle controller intervenes when the driver does not change gears. This circumvents the problem of having to set a gear corresponding to the vehicle speed after sailing.

Also, by an action of the driver, eg. When operating the accelerator pedal or the brake, the sailing operation can, for example, be terminated in the following manner: The clutch valve reduces the fluid pressure regulated, for example, the hydraulic pressure to the clutch and closes it, so that a gentle engagement takes place.

The present invention thus proposes a clutch start realized by means of the valve, the system cost of which is low.

• – Reduzierung der Starter-Starts durch Kupplungsstart
• – Günstiges Segel-System mit automatischem Kupplungsstart

Advantage of starting the clutch with a clutch valve:

• - Reduction of starter starts by coupling start
• - Favorable sail system with automatic clutch start

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Brief description of the drawings

1 shows in a graph a valve-controlled clutch start.

2 shows in a graph another valve-controlled clutch start.

3 shows an embodiment of a coupling arrangement for carrying out the method.

Embodiments of the invention

The invention is schematically illustrated by means of embodiments in the drawings and will be described in detail below with reference to the drawings.

In 1 an exemplary valve-controlled clutch start from the engine stop is shown. It is on an abscissa 50 the time is applied. At an ordinate 52 Different coupling states and speeds are plotted. With reference number 53 is the course of the coupling state and with reference numeral 55 the course of the speed of the motor is displayed. It can be seen that the clutch from clutch position "open" 54 monotonically rising closed 56 becomes. The valve regulates until the moment 58 a quick closing of the clutch up to condition 60 , After that, this position becomes state 60 held. If necessary, a slight positive slope of the clutch position may occur until the engine is at idle speed 62 was towed up. From the moment 70 The clutch is fully closed depending on the speed, until the target speed 72 is reached. The clutch start is after time 74 completed. The advantage of the valve-controlled clutch start is the variation of the parameters: the reaching of the state 60 at the time 70 as well as the regulated last engagement (from date 70 , Status 60 ) after (time 74 , Status 56 ) can be varied, for example, depending on the engine stop position, accelerator pedal position, engine temperature, speed, target speed and current actual speed. This represents a significant comfort advantage over a clutch start independently performed by the driver.

If, for example, after an engine idle phase, z. B. in an engine idle sailing, a clutch closing operation are carried out, similar to 1 the clutch is closed. This is in 2 shown. Again, the valve regulates until the time 58 a quick closing of the clutch up to condition 60 , It can be done accordingly 1 be continued. But it may also deviate in addition to the engine before reaching the state or the clutch position 60 to the desired target speed 72 be accelerated. This is done by a targeted engine torque intervention and thus enables a comfortable engagement, since the engine is not completely at target speed 72 has to be towed up. The subsequent speed adjustment, coming from above, is done by further closing the clutch.

3 shows on the basis of a hydraulic circuit diagram, the schematic structure of an embodiment of the coupling assembly, the total with the reference numeral 30 is designated. The illustration shows a clutch actuator 32 , in this case a clutch pedal, a master cylinder 34 with a surge tank 36 , a valve 38 , a slave or actuator cylinder 40 and a clutch 42 ,

The master cylinder 34 includes a piston that via the clutch actuator 32 introduced force absorbs and hydraulically to the slave cylinder 40 passes. This then actuates the clutch 42 , The valve 38 can be electrically controlled.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19856297 A1 [0002]

Claims (7)

Method for carrying out a clutch start in a motor vehicle with a clutch arrangement ( 30 ) in which one of a driver on a clutch actuator ( 32 ) introduced force by means of a fluid on a clutch ( 42 ), wherein the coupling ( 42 ) from a through a valve ( 38 ) open state with the valve ( 38 ) is closed. Method according to claim 1, which is carried out starting from an engine idling sailing, so that by closing the clutch ( 42 ) The engine is accelerated from an idle speed to a target speed. A method according to which is carried out starting from an engine stop sailing, so that by closing the clutch ( 42 ) The engine is accelerated from a speed of zero to a target speed. Method according to one of claims 1 to 3, wherein the closing of the clutch ( 42 ) is triggered by detecting an action of the driver. Method according to one of claims 1 to 3, wherein the closing of the clutch ( 42 ) is triggered by a motor control. Coupling arrangement for carrying out a clutch start in a motor vehicle, in particular for carrying out a method according to one of claims 1 to 5, with a clutch actuating element ( 32 ) and a clutch ( 42 ), wherein the coupling arrangement ( 30 ) is adapted to be driven by a driver on a clutch actuator ( 32 ) introduced force by means of a fluid on a clutch ( 42 ), whereby a valve ( 38 ), which is designed to prevent the coupling ( 42 ) from one through the valve ( 38 ) to keep it open. Clutch assembly arrangement according to claim 6, wherein the valve ( 38 ) in a hydraulic line between a master cylinder ( 34 ) and a slave cylinder ( 40 ) is arranged.

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