DE19937972A1 - Controlling motor vehicle drive system with automatic clutch and preferably automatic transmission by detecting if accelerator is depressed below maneuver threshold and controlling clutch to set maneuvering speed - Google Patents

Abstract

The method involves detecting if a drive unit (12) is operating, detecting if a gear is engaged in the transmission (24), and detecting the extent to which the accelerator pedal (56) has been depressed. If it is detected that the drive unit is operating, a starting gear is engaged, and the accelerator is depressed below a maneuver threshold, the clutch (18) is controlled to set a predetermined maneuvering speed. The drive unit may also be controlled to set the desired maneuvering speed. Independent claims are included for a method of controlling a drive system, and for a drive system.

Description

The present invention relates to a method for driving a Drive system, which drive system is a drive unit, a automated friction clutch and a transmission, preferably automati fixed gear, includes.

In such automated drive systems, there is generally Problem that when the vehicle is at a standstill or very slow driver is not possible by pressing down accordingly a clutch pedal and thus more or less strong interruption of the drive train to meter the vehicle slowly and slowly, for example for parking or maneuvering, or the vehicle sloping road against rolling in an undesired direction hold. Rather, the driver has to go through a corresponding low pressing the accelerator pedal maneuver the vehicle in such situations, due to the depression of the accelerator pedal, the clutch then more or less indented to generally a given one To transmit target torque. This often leads to the problem that a dosed or slow driving of the vehicle is difficult to achieve, especially on sloping roads.

DE 197 33 465 A1 discloses an arrangement for controlling a automated clutch, in which between different driving conditions, and especially when it is recognized that the vehicle is rolling in the wrong direction, for example at Engagement of the first forward gear rolls in the reverse direction Clutch is engaged to cause this rolling in the unwanted Counteracting direction.

It is the object of the present invention to provide a method for driving to provide a drive system or a drive system in which especially reliable in the area of standstill or when driving slowly a safeguard against unwanted movement of the vehicle is provided can be.

According to a first aspect, this object is achieved by a method for controlling a drive system, which drive system comprises a drive unit, an automated clutch device and a transmission, preferably an automated transmission, comprising the following steps:

• a) determining whether the drive unit is in operation,
• b) detecting whether a gear stage is engaged in the transmission,
• c) determining the extent to which a driving control device, preferably accelerator pedal is pressed,
• d) when it is detected in step a) that the drive unit in Operation is set, it is detected in step b) that in the transmission Gear, preferably starting gear, is engaged, and in Step c) it is detected that the drive operating device operates is, however, with one under a switching threshold operation actuation, actuation of the clutch direction for setting a predetermined shunting target speed speed.

An essential aspect of this method according to the invention is that especially in a driving state in which the driver locks the vehicle wants to maneuver, for example when parking, in a targeted manner a predetermined shunting target speed is set, and not immediately the vehicle according to the actuation of the driving control device is moved. This means as long as the extent of actuation of the Travel control device below the switching threshold actuation extent remains, it is recognized that the driver wishes to drive, but with  very slow speed. However, with such a low actuation dimensions it is often extremely difficult for a driver, in a defined way Way to specify a desired speed, and thus the There is a risk that he may be actuated by driving the driver slightly too strongly actuating device triggers too strong a reaction of the vehicle in this driving state, the vehicle according to the specified maneuvering Target speed moves so that a completely defined one for the driver and predictable response of the vehicle with a light push of the button Driving actuator results. The maneuvering becomes clear Simplified because the driver knows how to drive the vehicle at such a low level Actuation will respond. Only if through further operation the maneuvering actuation device the maneuvering threshold actuation extent is exceeded, for example, the clutch again immediately in Relation to the extent of actuation of the driving control device can be controlled in order to then drive the vehicle for normal driving or to move faster crawl according to the driver's desire.

To prevent that especially when maneuvering on the mountain through the Actuation of the clutch device and the resulting increase in transmitted clutch torque the drive unit in its speed is pressed too hard, it is also proposed that the drive aggregate for setting the shunting target speed is controlled.

To prevent excessive stress on the coupling device suggested that the coupling device or Drive unit only when the brake is not applied to adjust the maneuvering Target speed is controlled. It can also be provided that the target shunting speed is a non-zero speed is in the range of up to 5 km / h, preferably up to 3 km / h.

The above-mentioned object is also achieved by a drive system, comprising: a drive unit that is automated  Coupling device with a gear, preferably automated Gearbox in torque transmission connection or can be brought, a travel control device, preferably an accelerator pedal, according to the latter Operating range of the drive unit for torque delivery is controllable, a speed detection arrangement and a Control device for controlling the drive unit and / or the Coupling device.

It is then provided according to the invention that the control device the coupling device for setting a predetermined shunting Target speed controls when the drive unit is in operation is set, in the transmission a gear stage, preferably starting gear stage, is inserted and the travel control device in one of zero different under a switching threshold actuation extent Extent is actuated.

Even with such a system, it is again advantageous if the Control device also the drive unit for setting the Controls speed to the target shunting speed.

According to a further aspect of the present invention, the object mentioned at the outset is achieved by a method for controlling a drive system, which drive system comprises a drive unit, an automated clutch device and a transmission, preferably an automated transmission, comprising the following steps:

• a) determining whether the drive unit is in operation,
• b) detecting whether a gear stage is engaged in the transmission,
• c) Detect whether a drive operating device, preferably driving pedal is pressed,
• d) when it is detected in step a) that the drive unit in Operation is set, it is detected in step b) that a Gear, preferably starting gear, is engaged and in  Step c) it is detected that the drive operating device is not is actuated, actuating the coupling device for adjustment. a predetermined target speed.

This method is directed in particular to a driving state in which the vehicle is positioned on a sloping road to for example, when going uphill, for example inserted forward gear, there is a risk that at standstill, d. H. unactuated drive actuation device, the vehicle in the untended wanted direction, d. H. the backward direction. By the Defined setting of a predetermined target speed by means of the Driving the clutch device can ensure that the Vehicle is ultimately stopped or even slowly in the desired direction is moved.

It can be provided, for example, that the coupling device only is activated when a speed deviating from zero km / h is present.

This target speed can be, for example, a speed of Zero km / h. Alternatively, however, it is also possible that the target Such a speed in by inserting the Gear level desired direction of travel is that of a speed of Zero km / h deviates to an extent that the speed resolution corresponds to a speed detection arrangement.

As already mentioned at the beginning, this procedure can also be used be advantageous if the drive unit for adjusting the Target speed is controlled.

According to a further aspect, the present invention relates to a Drive system, comprising: a drive unit, which via an automati  based coupling device with a gear, preferably automatized transmission, is in the torque transmission connection or can be brought, a travel control device, preferably an accelerator pedal, according to the latter Operating range of the drive unit for torque delivery is controllable, a speed detection arrangement and a Control device for controlling the drive unit and / or the Coupling device.

It is then provided that the control device the clutch device for setting a target speed if the Drive unit is put into operation, one gear stage in the transmission, preferably start gear, and the drive actuation direction is not activated.

As already stated, the target speed can be zero km / h, or it can be provided that the target speed is in the range the speed resolution of the speed detection arrangement in the direction of zero km / h given by the selected gear deviating speed is.

Again, it is again advantageous if the drive unit for Setting the target speed is controlled.

In order to ensure that even with this procedure or with this drive system To avoid overloading the coupling device, it is proposed that the control device, the coupling device and / or that Drive unit only when the brake is not applied to set the target Controls speed.

The present invention will hereinafter be described with reference to the only one enclosed figure described, which schematically an inventive Represents drive system.  

This drive system 10 comprises a drive unit 12 , for example an internal combustion engine 12 , which is coupled via a drive shaft 14 to an input side 16 of an automated clutch, generally designated 18 . The output side of clutch 18 is connected via a transmission input shaft 22 to an automated transmission, generally designated 24 . The transmission 24 drives two driven wheels 30 , 32 via a transmission output shaft 26 and a differential 28 .

The drive system 10 further comprises a control device 34 which, as described below, interacts with various assemblies or components of this drive system 10 . The control device 34 thus controls the drive unit 12 via a power control arrangement 36 assigned to this drive unit 12 . It should be pointed out that this power control arrangement 36 can comprise any area that can be controlled to change the power output or the torque output of the drive unit 12 . This can be, for example, the injection, the throttle valve, the ignition system, the camshaft system or the like. This power control arrangement 36 thus receives corresponding control commands from the control device 34 in order to be able to provide the desired output torque of the drive unit 12 or the desired output speed. In a corresponding manner, the power control arrangement 36 outputs information to the control device 34 in order to be able to obtain knowledge thereof about the current operating state of the drive unit 12 .

The clutch 18 has associated with it an actuator arrangement 38 , which likewise interacts with the control device 34 in order to receive control commands from it for corresponding setting of the engagement or disengagement position and thus the torque transmission capacity of the clutch 18 . Furthermore, the actuator arrangement 38 can deliver information to the control device 34 which relates to the current actuating state of the clutch 18 . However, this information can also be supplied by other sensors provided in the coupling 18 itself.

The automated gearbox 24 likewise has an actuator arrangement 40 , by means of which gears in the gearbox 24 can be engaged and disengaged in the desired manner while driving the control device 34 . This activation can take place, for example, according to an actuation of a shift lever denoted by 42 , this actuation being detected, for example, by a shift lever sensor system 44 and a corresponding signal, as indicated by an arrow I, entered into the actuation device 34 .

Furthermore, the drive system has a plurality of sensors or sensor arrangements in order to be able to detect various other operating states. A speed sensor 46 is assigned to the drive shaft 14 , as is the transmission input shaft 22 , which is assigned a speed sensor 48 . A speed sensor 50 is also assigned to the transmission output shaft 26 , and the rotational speed of the driven wheels 30 , 32 can also be detected by the speed sensors 52 , 54 assigned to them. All of these sensors deliver their respective detection signals, which directly or indirectly contain information about the respective rotational speeds or speeds of the various components, to the control device 34 .

Furthermore, the drive system 10 has an accelerator pedal 56 to be referred to as a drive actuation device, the actuation extent of which is likewise directed to the control device 34 by a corresponding sensor arrangement. Based on this extent of actuation, the control device 34 then supplies the power control arrangement 36 with control commands for setting the power output of the drive unit 12 . It should be pointed out that other operating states or signals are of course also used to control the drive unit 12 .

Furthermore, the drive system 10 has a brake pedal 58 , the. Actuation or extent of actuation is also entered into the control device 34 for further processing. Additional sensors, generally designated 60 , can also be provided. These further sensors can, for example, provide information about the road gradient, the loading of a vehicle, the road friction coefficient and the like.

If a vehicle equipped with such a drive system is operated, for example, in such a way that it is to be maneuvered in slow travel, the system according to the invention can be used as follows: an operating state is assumed in which the drive unit 12 is put into operation, a gear stage is inserted in the gearbox 24 that is suitable for starting, that is. for example, the first or the second forward gear or the reverse gear, and initially the accelerator pedal 56 is not depressed, but the brake 58 is depressed to keep the vehicle at a standstill. It should be pointed out here that these different operating states can be detected by the above-mentioned sensors in the various assemblies or can then be concluded by evaluating the corresponding sensor signals that the respective operating states are present or not. In particular, with regard to the detection of whether the drive unit 12 is in operation, it is also possible to detect, for example, that an ignition key is in an operating rotational position, or, for example, the speed signal of the sensor 46 can be used to detect that the drive unit 12 is put into operation when at the same time, for example, the sensors 52 , 54 indicate that the vehicle is not moving or the actuator 38 provides information that the clutch 18 is in a disengaged state and thus cannot be the case that the shaft 14 is set in motion by a rolling vehicle. If the accelerator pedal 56 is now depressed slightly, as a result of which the driver indicates that he desires to drive, but at a very low speed, the driver's wish is recognized in the control device 34 by the determined degree of actuation of the accelerator pedal 56 is compared with a maneuvering threshold operation amount. If the actual actuation amount is below the maneuvering threshold actuation amount, ie if the entire actuation stroke of the accelerator pedal 56 is used only in an extremely small range, for example up to 5%, the clutch 18 , ie the actuator arrangement 38 assigned to it, is now actuated. to drive the clutch 18 in the direction of engaging and increasing the clutch torque. However, this activation takes place only when the accelerator pedal 56 has also released the brake pedal 58 , which is generally to be expected since both pedals can be actuated by a driver with the same foot. Due to the setting of the clutch in the direction of engagement, a stronger torque is now transmitted from the drive unit 12 in the downstream of the clutch 18 part of the drive system, so that the vehicle begins to roll. This roll-on is detected in particular by the speed sensors 48 , 50 , 52 and 54 , one of these sensor signals being sufficient here to be able to infer the actual vehicle speed. The detected or in the control device 34 then determined vehicle speed is compared with a predetermined for this maneuvering shunting target speed value, and when the detected or determined speed is below this target value, the clutch can be moved further towards engagement while then If the detected determined speed is above this setpoint, the clutch can be put back in the direction of disengagement. The vehicle speed is thus set in a control loop to a speed value which is at or in the range of the desired shunting speed.

In order to avoid an excessive pushing of the speed of the drive assembly 12 by the increasing engagement of the clutch 18 , if it is recognized from the signal or signals from the sensor 46 that the speed of the drive assembly 12 drops too much, this can also be controlled to increase its torque output. The control of the drive unit depends on the respective type or on the need to provide protection against excessive pressure on the speed. In internal combustion engines with a larger displacement, the risk of stalling or excessive pressure being applied to the rotational speed is relatively low, so that, for example, actuating the clutch 18 alone may be sufficient. With smaller, less powerful internal combustion engines, however, it can be advantageous to engage the. Coupling 18 additionally increase the power output of the drive unit 12 in order to avoid stuttering or stalling of the drive unit 12 . In addition, information about the road incline or the load can be used here, since the load on the drive unit becomes even greater when the uphill movement is slow.

The procedure according to the invention that, with only a slight actuation of the accelerator pedal 56, the clutch 18 or the drive unit 12 or the respective actuating arrangements 36 , 38 are not actuated directly in accordance with the actuation, but rather the actuation is carried out in such a way that a certain speed is set, has the essential advantage that inaccuracies in actuation when the accelerator pedal 56 is depressed cannot lead to an uncontrolled movement of the vehicle. This makes maneuvering much easier for the driver because he does not necessarily have to take care that the accelerator pedal is depressed very precisely. Rather, the driver knows that when the accelerator pedal is depressed slightly, a defined reaction of the vehicle, namely the movement at a defined speed, will occur. If the driver wants to go into a normal driving state, he can then continue to depress the accelerator pedal 56 , and if the maneuvering threshold actuation dimension is exceeded, the clutch 18 or the drive unit 12 can be actuated directly in accordance with the actuation extent.

Furthermore, when the accelerator pedal is released, this maneuvering mode can also be canceled or when the predetermined maneuvering target speed has been exceeded. Furthermore, it is advantageous to observe the frictional power generated in this slip operation of the clutch 18, in order to avoid overheating or overloading the same, particularly when using dry friction clutches. For example, the clutch load can be deduced over time from the slip and the clutch torque or the engine torque and the temperature by integrating these variables, and this maneuvering mode, in which the clutch 18 is in slip mode, can then be released by disengaging the clutch if it is recognized that the clutch has been subjected to excessive loads.

When the drive system 10 according to the invention is used on inclined terrain, there is also the possibility, in the manner described below, of ensuring that the vehicle does not begin to roll in an undesired manner in a direction which does not correspond to the intended direction of travel. Here too, for example, a state is again assumed in which the drive unit 12 is put into operation, a gear, in particular a starting gear (first gear, second gear or reverse gear) is engaged in the transmission 24 , the driver initially depresses the brake pedal 58 , to prevent the vehicle from rolling away, and accordingly the accelerator pedal 56 has not yet been actuated. If the driver now deliberately or unintentionally releases the brake pedal, there would basically be the risk that the vehicle would roll away in the undesired direction, for example roll backwards. In this operating state, a set speed of, for example, zero km / h is specified in the control device, which is ultimately a speed that corresponds to the state that the driver does not operate the accelerator pedal 56 . As soon as the vehicle rolls away, the clutch 18 is actuated in the direction of engagement, and if necessary the drive unit 12 can be activated at the same time to increase the power output in order to avoid again that the speed of the drive unit 12 is pressed so far via the clutch 18 that There is a risk of stalling, particularly in internal combustion engines. Again, the information about the loading, the road gradient and, if necessary, the coefficient of friction of the road surface can be used to control the power control arrangement 36 in such a way that the speed of the drive unit 12 is in a suitable range, for example in the range of the idling speed, depending on the engine type or slightly above.

Since certain speed inaccuracies or limited speed resolutions are present in the speed detection arrangements currently used, in particular the sensors used for this purpose, which can be in the range of up to 0.8 km / h, instead of specifying a target speed of zero km / h, a target speed can also be used be specified, which deviates from zero km / h in the area of the speed resolution, that is to say a nominal speed is specified which, for example, is approximately 0.8 km / h and corresponds to a direction in which the vehicle is moving in the engaged gear step during normal driving would. That is, it is then by adjusting the position or the clutch torque of the clutch 18, adjusting a speed of the vehicle to the minimally measurable, non-zero speed value. When performing such a control process, the vehicle speed will drop again to a value of zero or in the range of 0.8 km / h when the clutch 18 is partially lowered to reduce the speed, so that ultimately no continuous forward movement of the vehicle will take place, but instead a brief non-zero rolling of the vehicle occurs, which is immediately followed by a standstill or almost standstill.

Should the road gradient be so strong that the resilience of the. Coupling taking into account the specified speed is not possible, then, for example, when the maximum clutch torque the vehicle is not slow in itself roll back the desired direction, but still the by the provided at least partial engagement of the clutch braking effect is available.

Again, the load on the clutch can be carried out by monitoring the friction work introduced, based on the clutch torque and the speed difference between the input side 16 and the output side 20 of the clutch. If the friction work or friction power introduced is too great or exceeds a maximum permissible value, the clutch can be linearly graded or otherwise opened successively or / and the engine torque can be reduced in order to avoid overloading the clutch, which is particularly true when the clutch is running dry Friction clutch is of great importance. Furthermore, this safety function can also be canceled if the vehicle actually starts to roll in the correct direction or the accelerator pedal is operated.

The two procedures described above make it possible the driver of a vehicle handling it in particular a very low speed range much easier to do because there is a defined movement of the vehicle when maneuvering is achieved and secondly when driving in mountainous terrain, in particular when starting off, the driver does not change very quickly from  Brake pedal on the accelerator pedal must ensure that the vehicle is not rolls backwards, but is already active when you release the brake pedal through the intervention in the clutch system or the management of the Drive unit is ensured that an undesired rolling away largely cannot occur.

Claims (15)

1. A method for controlling a drive system, which drive system comprises a drive unit ( 12 ), an automated clutch device ( 18 ) and a transmission ( 24 ), preferably an automated transmission ( 24 ), comprising the following steps:

• a) detecting whether the drive unit ( 12 ) is started,
• b) detecting whether a gear stage is engaged in the transmission ( 24 ),
• c) detecting the extent to which a driving actuation device ( 56 ), preferably an accelerator pedal ( 56 ), is actuated,
• d) when it is detected in step a) that the drive unit ( 12 ) is put into operation, in step b) it is detected that a gear stage, preferably the starting gear stage, is engaged in the transmission ( 24 ), and in Step c) it is detected that the driving actuating device ( 56 ) is actuated, but with an actuating amount lying below a maneuvering threshold actuating amount, actuating the coupling device ( 18 ) to set a predetermined desired maneuvering speed.

2. The method according to claim 1, characterized in that the drive unit ( 12 ) is also controlled for setting the maneuvering target speed. 3. The method according to claim 1 or 2, characterized in that the coupling device ( 18 ) or, respectively, the drive unit ( 12 ) is only activated when the brake is not actuated to set the maneuvering target speed. 4. The method according to any one of claims 1 to 3,  characterized in that the target shunting speed is a non-zero speed in the range of up to 5 km / h, preferably up to 3 km / h. 5. Propulsion system comprising:

• - A drive unit ( 12 ) which is or can be brought into a torque transmission connection via an automated coupling device ( 18 ) with a transmission ( 24 ), preferably as an automated transmission ( 24 ),
• - a drive actuation device ( 56 ), preferably an accelerator pedal ( 56 ), according to the extent of its actuation the drive unit ( 12 ) can be actuated for torque output,
• a speed detection arrangement ( 48 , 50 , 52 , 54 , 34 ),
• - A control device ( 34 ) for controlling the drive unit ( 12 ) and / or the coupling device ( 18 ),

characterized in that the control device ( 34 ) controls the coupling device for setting a predetermined maneuvering target speed when the drive unit ( 12 ) is in operation, a gear stage, preferably starting gear stage, is inserted in the transmission ( 24 ) and the drive actuating device ( 56 ) is operated to a non-zero extent below a marshalling threshold actuation amount. 6. Drive system according to claim 5, characterized in that the control device ( 34 ) further controls the drive unit ( 12 ) to adjust the speed to the desired maneuvering speed. 7. A method for controlling a drive system, which drive system comprises a drive unit ( 12 ), an automated clutch device ( 18 ) and a transmission ( 24 ), preferably an automated transmission ( 24 ), comprising the following steps:

• a) detecting whether the drive unit ( 12 ) is started,
• b) detecting whether a gear stage is engaged in the transmission ( 24 ),
• c) detecting whether a drive actuation device ( 56 ), preferably an accelerator pedal ( 56 ), is actuated,
• d) when it is detected in step a) that the drive unit ( 12 ) is put into operation, it is detected in step b) that a gear stage, preferably the starting gear stage, is engaged in the transmission ( 24 ) and in step c) it is detected that the driving actuating device ( 56 ) is not actuated, actuating the coupling device ( 18 ) to set a predetermined target speed.

8. The method according to claim 7, characterized in that the coupling device ( 18 ) is only activated when a speed deviating from zero km / h is present. 9. The method according to claim 7 or 8, characterized in that as the target speed a Ge speed of zero km / h or in the speed resolution range of a speed detection arrangement ( 48 , 50 , 52 , 54 , 34 ) in the direction of a gear selected before the given direction is set to a speed other than zero km / h. 10. The method according to any one of claims 7 to 9, characterized in that the drive unit ( 12 ) is also controlled for setting the target speed. 11. Drive system comprising:

• - A drive unit ( 12 ) which is or can be brought into a torque transmission connection via an automated coupling device ( 18 ) with a transmission ( 24 ), preferably as an automated transmission ( 24 ),
• - a drive actuation device ( 56 ), preferably an accelerator pedal ( 56 ), according to the extent of its actuation the drive unit ( 12 ) can be actuated for torque output,
• - a speed detection arrangement ( 48 , 50 , 52 , 54 , 34 ) '
• - A control device ( 34 ) for controlling the drive unit ( 12 ) and / or the coupling device ( 18 ),

characterized in that the control device ( 34 ) controls the clutch device ( 18 ) to set a target speed when the drive unit ( 12 ) is in operation, a gear stage, preferably the starting gear stage, is inserted in the transmission ( 24 ), and the drive actuation device ( 56 ) is not actuated. 12. Drive system according to claim 11, characterized in that the target speed at zero km / h lies. 13. Drive system according to claim 11, characterized in that the target speed is a in the area of the speed resolution of the speed detection arrangement ( 48 , 50 , 52 , 54 , 34 ) in the direction specified by the gear position of zero km / h different speed . 14. Drive system according to one of claims 11 to 13, characterized in that the control device ( 34 ) further controls the drive unit ( 12 ) for setting the target speed. 15. Drive system according to one of claims 11 to 14, characterized in that the control device ( 34 ) controls the coupling device ( 18 ) and / or the drive unit ( 12 ) only when the brake is not actuated to set the target speed.