DE102010052385A1 - Method for controlling swing utilization operation of drive train of motor vehicle, involves activating swing utilization operation when torque request is terminated and certain auxiliary conditions are met - Google Patents

Abstract

The method involves activating the swing utilization operation when the torque request is terminated and certain auxiliary conditions are met. The temperature of the drive unit is greater than 30 degrees Celsius and the charging condition of a battery is greater than 25 percent for staring the drive unit. The vehicle speed is greater than 15 kilometers per hour and 20 percent of brake power reserve is available.

Description

The invention relates to a method having the features according to the preamble of claim 1.

The publication DE 197 02 554 A1 discloses a method which is intended to provide greater safety as well as lower fuel consumption in driving conditions such as "engine brake", "drive in thrust", "coast out", etc. It is provided depending on the situation, to switch to lower gears, to perform a fuel cut or to interrupt the adhesion in the drive train by opening the clutch.

Furthermore, a momentum automatic, for example, already known from the VW Golf III, which is still to judge today standards as uncomfortable.

For an economical and comfortable operation of an automatic vehicle, which has, for example, a dual-clutch system, the clutch function must meet a variety of requirements.

In today's car, a very high effort is made to save fuel (generator management, closable radiator fins, etc.). In vehicles with automatic transmissions, an improvement in the efficiency of individual components as in the case of the drive motor - referred to in the context of this document for short as an engine - or the transmission is also sought. In addition, a correspondingly optimized switching point selection attempts to drive in a fuel-efficient operating point.

Another useful measure is to operate the engine as economically as possible. For this example, as soon as the accelerator pedal - in the Rahen this document also referred to as accelerator pedal - is withdrawn, carried out in all modern internal combustion engines, a fuel cut, during which no fuel is needed. However, it comes then in overrun due to the internal engine friction to engine friction losses (engine thrust). This often results in a greater delay than actually desired. In order to compensate for this excessive unwanted delay, fuel must ultimately be burnt again.

The invention has for its object to provide ways to avoid this undesirable delay with the lowest possible fuel consumption.

Especially in dual-clutch systems with a highly dynamic clutch drive system and an intensive engine access - but also in other particularly automated transmission-clutch systems - here offers an improvement in the operating strategy to further reduce fuel consumption. Here it is favorable in phases where no power is needed but also no significant delay is desired - for example, during coasting - turn off the engine and decouple from the driveline to the shear torque in the engine does not act as a vehicle deceleration.

The object is achieved by a method having the features according to claim 1.

• – Temperatur der Antriebseinheit größer als 30 Grad Celsius,
• – Ladezustand einer Batterie zum Starten der Antriebseinheit größer 25%,
• – Fahrzeuggeschwindigkeit größer als 15 Kilometer pro Stunde,
• – mindestens 20% Bremskraftreserve vorhanden.

According to the invention, a method for controlling a flywheeling operation in a drive train of a motor vehicle having a drive unit, a transmission and a clutch is proposed, wherein the flywheel operation is activated when the load request is terminated and the following secondary conditions are fulfilled:

• - temperature of the drive unit greater than 30 degrees Celsius,
• Charge state of a battery for starting the drive unit greater than 25%,
• Vehicle speed greater than 15 kilometers per hour,
• - At least 20% brake reserve available.

The advantage is that unwanted delays can be avoided with the lowest possible fuel consumption.

In a preferred embodiment of the invention, the engine temperature is in particular about 50 ° C and / or
the state of charge of the battery in particular about 30% and / or
the vehicle speed in particular about 30 kilometers per hour and / or
in particular about 40% are available as brake reserve.

In a preferred embodiment of the invention, upon activation of the flywheel mode, the clutch is disengaged and the engine is stopped.

In a further preferred embodiment of the invention, the transmission is set to N upon activation of the flywheel operation.

In a particularly preferred embodiment of the invention, the flywheel mode is deactivated when a load request is initiated.

In a further preferred embodiment of the invention, upon deactivation of the flywheel operation, the engine is started and a gear is engaged and the clutch is closed.

In a further preferred embodiment of the invention, upon deactivation of the flywheeling operation and at a vehicle speed above a first predetermined threshold value, a predetermined gear is engaged and then the clutch is closed so that the engine is brought to rotational speed and thereby started.

In a further preferred embodiment of the invention, upon deactivation of the flywheeling operation and at a vehicle speed above a first predetermined threshold value and in the presence of a suitable coefficient of friction of the road, a predetermined gear is engaged and then the clutch is closed so that the engine is brought to rotational speed and thereby started.

In a further preferred embodiment of the invention, there is a suitable coefficient of friction property of the road when it is determined that the coefficient of friction of the road is high enough to prevent slippage of the wheels when closing the clutch and to bring the engine to speed.

In a further preferred embodiment of the invention, the predetermined gear is determined such that the gear is the largest possible gear, but the transmission input speed would be at least a predetermined value above the idle speed when it is engaged at the present vehicle speed and by closing the clutch the power flow would be made.

In a further preferred embodiment of the invention, the predetermined value is 50 to 500 revolutions per minute, preferably 200 revolutions per minute.

In a further alternative embodiment of the invention, the predetermined gear is determined such that the gear is the largest possible gear, but at the transmission input speed is at least 1000 revolutions per minute, when inserted at the present vehicle speed and by closing the clutch Power flow would be produced.

In a further preferred embodiment of the invention, upon deactivation of the flywheeling operation and at a vehicle speed below a second predetermined threshold value, the engine is started by means of the engine start unit, a predetermined gear is engaged and then the clutch is closed.

In a further preferred embodiment of the invention, the first predetermined threshold value corresponds to the second predetermined threshold value and is between 30 kilometers per hour and 60 kilometers per hour, preferably 40 kilometers per hour.

In a further preferred embodiment of the invention, when it is determined that a secondary condition is no longer met, it is determined whether it makes more economic sense in terms of fuel consumption to engage the predetermined gear, close the clutch, and apply the engine in thrust operate or idle the engine while the clutch is open.

In a further preferred embodiment of the invention, if it is detected on the basis of information, in particular by a navigation device, that the vehicle speed has to be reduced, it is signaled by an indication that an activation of the swing-use mode should take place so that the driver terminates the load request on the basis of the display and thereby the momentum utilization mode is activated.

According to the invention, a computer program product with a computer program is proposed which has software means for carrying out the above-mentioned methods when the computer program is executed on a computer. Such a computer may be part of the control device.

• – Temperatur der Antriebseinheit größer als 30 Grad Celsius,
• – Ladezustand einer Batterie zum Starten der Antriebseinheit größer 25%,
• – Fahrzeuggeschwindigkeit größer als 15 Kilometer pro Stunde,
• – mindestens 20% Bremskraftreserve vorhanden.

The invention also proposes a device for controlling a flywheeling operation in a drive train of a motor vehicle having a drive unit, a transmission and a clutch and a control device, wherein the control device is provided for activating the flywheel operation when the load request is terminated and fulfills the following secondary conditions are:

• - temperature of the drive unit greater than 30 degrees Celsius,
• Charge state of a battery for starting the drive unit greater than 25%,
• Vehicle speed greater than 15 kilometers per hour,
• - At least 20% brake reserve available.

Further advantages and advantageous embodiments of the invention are the subject of the following figures and their description.

They show in detail:

1 Example of the method according to the invention applied in a vehicle with dual-clutch transmission

2 schematic representation of an embodiment of the method according to the invention

According to the invention, it is proposed to ensure a further reduction in consumption in vehicle operation by the following strategy measures in the functional software.

1) Enable and Disable Flywheel Operation

If the driver of the accelerator pedal - so when the accelerator pedal is no longer operated by the driver and is in its unactuated position - and there are sufficient conditions below to activate the fly-power operation, then disengaged and the engine is turned off. Conveniently, the transmission is set to N.

The sufficient secondary conditions are at least:
Motor temperature> value_1
Battery charge status> Value_2
Vehicle speed> value_3
Sufficient brake reserve available

Wert_1 is about 30 to 70 degrees Celsius, preferably about 50 ° C,
Wert_2 about 25% to 40%, preferably about 30% and
Wert_3 about 15 to 50 kilometers per hour, preferably about 30 kilometers per hour. As a brake reserve is at least 20 to 50%, preferably about 40% available.

Of course, the stated values must be determined individually for each vehicle.

If the driver returns to the accelerator pedal - ie when the driver presses the accelerator pedal again - it is intended that the engine be restarted and a gear engaged. There are different possibilities in different cases:

Version 1):

Is the vehicle speed sufficiently large - for example, greater than 40 km / h - then a suitable, the largest possible gear is determined and preselected - that is inserted - in which the associated transmission input speed would be at least a defined, predetermined value above the idle speed, if in Present vehicle speed would be established by closing the clutch of power flow.

Alternatively, the appropriate gear is determined such that its associated transmission input speed at the present vehicle speed minus a speed value that will result from the expected speed reduction on towing the engine is engaged and the power flow is established.

The predetermined value should be about 100 to 500 revolutions per minute, preferably 200 revolutions per minute. The predetermined value should be greater than the resulting speed reduction of the transmission input speed when the engine is cranked so that the transmission input speed is not below idle speed after the engine has been cranked.

Alternatively, the predetermined value should be predetermined so that it adds up to about 1000 revolutions per minute added to the idle speed of the engine.

In a further alternative, the predetermined gear is determined such that the gear is the largest possible gear, but at the transmission input speed is at least 1000 revolutions per minute, if it were engaged at the present vehicle speed and produced by closing the clutch power flow.

As an extension or supplement to the above cases, it is additionally checked to what extent the predefined gear corresponds to the target gear from the gear selection, which is calculated by the transmission control unit, that is to say, to what extent. H. the driving situation is appropriate and corresponds to the driver's request. If this target gear from the gear selection also fulfills the other secondary conditions, this selection has a particularly good suitability. This also ensures that the transmission input speed is high enough to reliably start the engine by closing the clutch.

Subsequently, by closing the clutch as in a tow start (Tow) the engine - without the aid of the starter - brought to speed and started by. The engine can then deliver torque based on the accelerator pedal position when requested by the driver. Advantage: There is no additional battery power for the starter - in the context of this document also referred to as engine start unit - necessary.

However, it must be determined whether the road conditions allow it, ie whether the coefficient of friction of the road is high enough to prevent it from slipping To prevent the wheels, as could be the case for example in case of smoothness. Such determination of the road conditions is made according to methods known in the art and does not form part of the invention itself.

Variant 2):

Below a certain vehicle speed - for example less than 40 km / h - variant 1) can no longer be performed. Therefore, when accelerating - so when pressing the accelerator pedal - the engine is first started by the starter and then engaged. The engagement and the insertion of a suitable gear is carried out according to known from the prior art method in particular topics such as "freewheel" (gear engaged but clutch open) and "start" depending on what vehicle speed is present and / or which gear active is.

In 1 is shown to variant 1) an example based on a dual-clutch transmission.

This designates in 1 Accelerator pedal ( 200 ) the operation of the accelerator pedal in angle degrees. v_fzg ( 210 ) denotes the vehicle speed. Wave 1 ( 220 ) or 2 ( 230 ) denotes the engaged gear on the respective shaft of the partial transmission 1 and 2 respectively.

NMot ( 240 ) denotes the speed of the motor, NInp1 ( 250 ) or NInp2 ( 260 ) denotes the speed of the transmission input shaft of the partial transmission 1 and 2 respectively.

MMot ( 270 ) denotes the engine torque, MKupp1 ( 280 ) or MKupp2 ( 290 ) denotes the clutch torque of the clutch on the shaft 1 and 2, wherein between the engine and the transmission input shaft of the partial transmission 1 and 2 each a clutch is arranged.

In 1 the driver is at the time 35 seconds off the accelerator pedal, the momentum use mode is activated, thereby turning off the engine and the gear laid out - the vehicle rolls. At about 50 seconds, the driver's request for acceleration by pressing the accelerator pedal. A gear is then engaged, the clutch is closed and the engine towed. The positive engine torque increases the vehicle speed.

2) Examination of the secondary conditions

If one or more secondary conditions are no longer valid in the flywheel mode, a corresponding calculation of the operating parameters, such as an evaluation of the consumption maps and the thrust torques, must be used to determine whether it makes more economic sense in terms of fuel consumption to engage the gear, close the clutch and shut off the engine to operate in thrust or only to operate the engine at idle with the clutch open.

2 schematically shows an embodiment of the method according to the invention. Starting from normal operation in step 10 will be in step 20 Verifies that the driver is off the accelerator at this time and that the constraints listed above are met. The condition that the driver at this time from the gas goes - which is referred to in this document as the end of a load request - is then satisfied if the driver in the current review the accelerator pedal is no longer actuated, so it is in its rest position is found during a review in time immediately before that the driver has still pressed the accelerator pedal, so it was not yet in its rest position. If the conditions of step 20 are not met, it will continue in normal operation 10 remained. Are the conditions in step 20 however, it is met in step 30 the flywheel mode is activated, the current torque-transmitting clutch is opened, the engine is switched off and the transmission is moved to neutral position. Subsequently, in step 40 further verifies that the constraints are still met. If not, will step in 80 the shear efficiency mode deactivated and proceed as in point 2 in this document "Examination of the secondary conditions". Are in step 40 the constraints met will be in step 50 Checks if the driver starts to press the accelerator again at this time. The condition that the driver at this time begins to press the accelerator pedal - which is referred to in this document as the beginning of a load request - is then satisfied if the driver presses the gas pedal in the current review, so it is not is more in its rest position while a check was found in time immediately before that the driver has not pressed the accelerator pedal, so it was in its rest position. Is the condition in step 50 not fulfilled, becomes step 40 returned. Is the condition in step 50 is met, in step 60 checks whether the vehicle speed is greater than a predetermined threshold - for example, 40 km / h - and whether the coefficient of friction of the road is sufficiently high. If not, will step in 90 the thrust mode deactivated, the engine started with the starter, a gear engaged and engaged. Subsequently, in step 100 transferred to normal operation. Are the conditions in step 60 is met, in step 70 the thrust utility mode deactivated, a gear engaged, engaged and brought the engine to speed. Subsequently, in step 100 continue in normal operation.

3) Optimization of the use of flywheeling operation

In the context of intelligent navigation devices, the time when the momentum utilization mode is to be activated can be further improved. For example, special modes such as EcoRoute etc. are available in navigation systems. So the driver should be encouraged to an economical driving behavior. Is therefore recognizable that z. B. at a certain distance, the maximum speed due to a locality, etc. must be reduced or a corresponding vehicle deceleration is desired, it can be signaled by an appropriate display and / or coupling in the instrument cluster to the driver that an activation of the flywheel operation should take place. Then, the fly-by mode is activated when the driver goes off the accelerator pedal due to the display.

Summary:

Optimization of the drive system of the clutch, that in favorable driving situations where no significant vehicle deceleration is desired, a flywheel automatic is realized. Clutch opening and uncoupling of the off motor will not result in unnecessary losses.

Field of application of the invention are vehicles with automated manual transmissions, such as dual-clutch transmission - also called parallel shift transmission.

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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 19702554 A1 [0002]

Claims (10)

Method for controlling a fly-power operation in a drive train of a motor vehicle with a drive unit, a transmission and a clutch, characterized in that the fly-use operation is activated when the load request is terminated and the following constraints are met: - temperature of the drive unit greater than 30 degrees Celsius, - Charge state of a battery to start the drive unit greater than 25%, - Vehicle speed greater than 15 kilometers per hour, - At least 20% reserve brake power available. Method according to claim 1, characterized in that the engine temperature in particular about 50 ° C and / or the state of charge of the battery in particular about 30% and / or the vehicle speed is in particular about 30 kilometers per hour and / or in particular about 40% are available as brake reserve. Method according to one of the preceding claims, characterized in that on activation of the fly-power operation, the clutch disengaged and the engine is turned off. Method according to one of the preceding claims, characterized in that upon activation of the fly-power operation, the transmission is set to N. Method according to one of the preceding claims, characterized in that the fly-use mode is deactivated when a load request starts. A method according to claim 5, characterized in that upon deactivation of the fly-power operation, the engine is started and a gear engaged and the clutch is closed. Method according to one of claims 5 or 6, characterized in that when deactivating the Schwungnutzbetriebs and at a vehicle speed above a first predetermined threshold, a predetermined gear engaged and then the clutch is closed, so that the engine is brought to speed and thereby started. Method according to one of claims 5 or 6, characterized in that when deactivating the Schwungnutzbetriebs and at a vehicle speed above a first predetermined threshold and in the presence of a suitable coefficient of friction of the road a predetermined gear is engaged and then the clutch is closed, so that the engine speed brought and thereby started. Method according to one of claims 7 or 8, characterized in that there is a suitable coefficient of friction property of the road, when it is determined that the coefficient of friction of the road is high enough to prevent slippage of the wheels when closing the clutch and at speed of the engine prevent. Method according to one of claims 7 or 8, characterized in that the predetermined gear is determined such that the gear is the largest possible gear, but in which the transmission input speed would be at least a predetermined value above the idle speed, if at the present vehicle speed inserted and by closing the clutch the power flow would be made.

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