DE102011003042A1 - Method for controlling automatic switching process of combustion engine of e.g. motor vehicle, involves delaying partial or complete clutch operation for closing clutch until automatic started drive unit is ready - Google Patents

Abstract

The method involves monitoring a clutch signal of a clutch sensor element (21) in a standby state and a switching position of a vehicle transmission. A defined start condition for an automatic switching of a switched-off drive unit is present when an engaged gear and the clutch signal for closing of an opened clutch of a vehicle are detected as the switching position. A partial or complete clutch operation for closing the clutch is delayed, until the automatic started drive unit is ready. An independent claim is also included for a starter control device for controlling an automatic switching process of a drive unit of a motor vehicle.

Description

The invention relates to a method for controlling an automatic connection operation of a drive unit according to the preamble of claim 1 and to a corresponding start control device according to the preamble of claim 3.

In order to reduce fuel consumption and pollutant emissions, methods and systems are currently being developed and partly already in use which contain a start-stop function which automatically switches off the drive unit of a motor vehicle designed as an internal combustion engine under certain conditions or given predetermined switch-off conditions Presence of specified connection conditions automatically turn on again. Such methods and systems are particularly suitable for city traffic to reduce fuel consumption, since in city traffic, the vehicle often stops at traffic lights or traffic and the operation of the internal combustion engine is not required.

Thus, for example, a shutdown condition for the drive unit is detected when a gear selector lever is brought into neutral position at standstill of the vehicle, so that no gear is engaged, and at the same time the clutch is closed by relieving the kicked clutch pedal.

An associated turn-on condition for a drive unit disabled by the start-stop function is detected when the clutch pedal of the vehicle is stepped again and at the same time the gear selector lever is in the neutral position.

However, the known method presupposes that the driver of the vehicle has to release the vehicle to release the clutch when the vehicle is at a standstill. This means that the clutch pedal must not be stepped. However, since a large number of drivers in the state of the vehicle entered the clutch pedal and thus keeps the clutch operated, there is no shutdown of the drive unit for lack of fulfillment of the stop condition. The drive unit consequently remains in operation.

There are therefore known from the prior art start-stop systems, which enable a shutdown of the drive unit already due to an actuation of the clutch and make it impossible to insert the neutral position. For example, the DE 10 2004 024 212 A1 a method for controlling an operation of a motor vehicle with automatic start-stop, which includes a shutdown that automatically shuts off the engine in the presence of a stop condition. Such a stop condition exists when a vehicle speed is greater than 0 km / h and at least the clutch is opened. This means that the internal combustion engine is already switched off when the vehicle is coasting off the vehicle by actuating the clutch pedal and the clutch is thereby opened. A shutdown is thus without a duty of the driver to release the clutch pedal following a pedaling of the clutch pedal.

Thus, it is necessary to provide a subsequent start-up adapted thereto Anschaltbedingung, since the previously envisaged pedaling of the clutch is not necessary in this case and therefore can be omitted.

From the DE 10 2004 024 212 A1 It is also known to define a turn-on condition for restarting the drive unit by closing a clutch, wherein a speed greater than zero may be present.

This means that the drive unit is only started automatically when the clutch or the clutch pedal is released when the gear is engaged. Only when the subsequent closing of the clutch thus takes place starting the drive unit. However, since a start-up of the drive unit at the same time as the closing of the clutch takes a certain amount of time until an operable state, in particular in an internal combustion engine, there is a risk that the clutch will be closed before the drive unit has reached its operational state. The result is a stalling of the drive unit by closing the clutch.

A stalling of the engine is always a annoying for the driver's delay but also a critical danger situation, whereby, for example, backlogs at traffic lights and intersections but also rear-end collisions are provoked. It is therefore proposed in the prior art, especially for hybrid vehicles, to use additional high-performance electric motors as starters in order to enable a rapid startup of the internal combustion engine. However, this requires very powerful and therefore expensive components.

It is therefore an object of the invention to provide a method and a control device for controlling an automatic connection process, which as late as possible but safe restarting the drive unit is made possible without generating hazardous situations by stalling the drive unit and only minor and cost-effective changes to existing systems required power. In addition, a uniform use for different vehicle concepts, in particular for Vehicles with combustion or hybrid drives, be enabled.

This object is achieved by a method according to claim 1, and a tempering control device according to claim 3. Advantageous developments emerge from the dependent claims.

Accordingly, a method for controlling an automatic connection operation of a drive unit of a motor vehicle is proposed, wherein the motor vehicle comprises a start-stop system for switching between a normal operating state with the drive unit switched on and a standby state with the drive unit switched off. In the standby state, a clutch signal of a clutch encoder element and also a shift position of a vehicle transmission is monitored. A first defined start condition for automatically switching on the switched-off drive unit is present when, as the shift position, an engaged gear and at the same time a clutch signal for closing an opened clutch of the vehicle are detected. A partial or complete clutch closure to close the clutch is delayed until the automatically started drive unit is ready for operation.

This means that a clutch must be opened and a gear engaged as a prerequisite for a restart of the switched off in a motor start-stop function drive unit. The clutch or the clutch pedal is thus kicked and a gear selector lever is in the switching position. Preferably, the gear selector lever is in the first gear of the vehicle in view of the imminent launch of the vehicle. Of course, another gear, in particular a second or third as well as the reverse gear can be engaged for starting. The decisive factor is that a turn-on condition for turning on the drive unit is only satisfied when a closing of the clutch is initiated by a corresponding clutch signal for closing the clutch. The coupling signal is triggered for this purpose, for example, by an actuation of the coupling element. On the one hand, this offers the possibility of additionally extending a time interval between switching off the drive unit and switching on again, and of gaining valuable time when actuating the clutch and engaging the gear.

Since the closing of the clutch up to a coupling point or a complete engagement usually takes place within a short time interval, it must be ensured that the drive unit has been started and started up in the meantime and is thus in the ready-to-operate state. This can be defined by the fact that a sufficiently high speed is reached at which engagement and starting can be ensured without "stalling" the drive unit due to the load on the coupling caused by coupling. For this purpose, an engagement is delayed in time so that the drive unit is provided sufficient time to reach the required speed. The required speed also depends on a selected by the gear engaged gear ratio and the current vehicle speed.

A delay in the sense of this invention may mean both a delay in the triggering of a coupling process, for example, a time-delayed movement of the clutch or a Kupplungsauslenkers, or a slowing down of the engagement process. In the latter case, for example, a slowed back movement of the clutch or the Kupplungsauslenkers done. As a result, a time interval between a release of the clutch encoder element for closing the clutch and reaching a Einkuppelpunktes (partial clutch closure) or reaching a complete clutch closure is increased. The drive unit thus has a little more time to reach the ready state. An "stalling" of the drive unit can be prevented with appropriate tuning of the delay.

Preferably, the delay is predetermined such that an engagement coincides directly with the achievement of the operating state or immediately subsequent thereto. In this way, the delay can be as short as possible and thus almost unnoticed by a driver of the vehicle without reducing ease of use by (unnecessarily) occurring waiting times.

Preferably, the clutch encoder element comprises a clutch master cylinder with a clutch pedal operatively coupled, and the clutch signal is generated to close the opened clutch by releasing the kicked clutch pedal. Of course, other coupling elements are possible as well. In particular, an electronic clutch transmitter in the form of an electronic switch for triggering a clutch signal for closing the opened clutch is possible.

Furthermore, a starting control device for controlling an automatic starting operation of a drive unit of a motor vehicle is provided with a clutch release system for actuating the clutch of the vehicle and means for monitoring and detecting the clutch signal of the clutch release system and means for Detecting a shift position of a vehicle transmission and a control unit, which is designed for carrying out the method described above and for at least partially controlling the start control device. In addition, the starting control device includes delay means for delaying the partial or complete clutch closing to close the clutch until the automatically started drive unit is ready for operation.

Accordingly, the starting control device thus comprises a clutch release system. This is intended to provide an active coupling between the driver and the clutch. A movement of the driver or the actuation of a coupling element, such as a stepping of a clutch pedal, by means of the clutch release system in a release of the clutch, in particular a disengagement, implemented. Furthermore, the exhaust control device comprises means for monitoring and detecting the clutch signal of the clutch encoder element. On the basis of these means can be detected when and / or how or to what extent the clutch sensor element is actuated and whether or which clutch signal is triggered. For example, it can be determined whether a clutch signal is generated to close or to open the clutch. The means are operatively coupled in terms of communication with the control unit for monitoring and detecting the clutch signal by means of the control unit, so that at least the said information can be forwarded to the control unit for carrying out the described method.

Furthermore, the starting control device comprises the said means for detecting a shift position of the vehicle transmission, so that it can be determined whether a gear and / or gear is engaged. These means are also communicatively coupled with the control unit in order to provide the said information to the control unit for processing.

This means that in the control unit, the information determined by means of said means converge and can be processed there according to the described method.

In order to provide the described deceleration of the clutch closure to close the clutch, the starting control device comprises the described delaying means. These are also preferably operatively coupled to the control unit, wherein control of the delay means by the control unit enables control of the delay of the partial or full clutch closure.

Preferably, the clutch release system comprises a hydraulic clutch element with a clutch master cylinder for pressurizing a hydraulic fluid and a clutch slave element with a clutch slave cylinder for actuating a clutch release. The clutch master cylinder and the clutch slave cylinder are operatively coupled via a hydraulic fluid having hydraulic line. In addition, the delay means comprises a control valve to delay a return flow of the hydraulic fluid from the clutch slave cylinder to the clutch master cylinder.

Thus, the clutch release system may be formed as a hydraulic release system and substantially corresponds to the conventionally known systems, with the exception of the additional delay means provided in the clutch release system. This provides the possibility to provide a delayed Kupplungsausrücksystem without costly changes to existing systems. This therefore preferably comprises the control valve and thus enables a regulation of a flow of the hydraulic fluid through the clutch release system. In particular, the described backflow of the hydraulic fluid should be delayed from the clutch slave cylinder to the clutch master cylinder. This means that relieving the clutch master cylinder, for example, by releasing the kicked and acting on the clutch master cylinder clutch pedal by the driver, does not lead to an immediate and rapid return flow of hydraulic fluid to the clutch master cylinder.

Rather, the hydraulic fluid must pass on its way back the control valve, which allows depending on the setting only a defined flow velocity of the hydraulic fluid and thus delays the reflux. This causes the fluid volume located in the clutch slave cylinder to be decelerated only slowly and thus a slowed down reset of the clutch slave cylinder takes place. The clutch thus remains in the meantime at least partially solved and is therefore closed at a reduced speed. The comparative representation of the speeds refers to a closing speed of a conventional clutch or a conventional clutch release system without control valve.

In order to prevent blocking or obstruction of a functional range of the clutch or the clutch release system in the event of a failure of the control valve, the control valve is configured so that it is fully open in a de-energized or signalless state and thus no delay of the hydraulic fluid is made.

According to a further embodiment, the clutch release system further comprises a check valve which is arranged parallel to the control valve and oriented so that the hydraulic fluid can flow through the check valve at any time from the hydraulic encoder cylinder to the clutch slave cylinder and thus at any time allows actuation of the clutch slave cylinder. The check valve thus prevents backflow of the hydraulic fluid through the check valve, so that the hydraulic fluid must inevitably flow through the control valve to return to the clutch master cylinder. However, the check valve allows unimpeded flow in the opposite direction to disengage the clutch. This represents a safety-relevant aspect, since in this way the driver always has the opportunity to actuate the clutch to disengage and thus to separate the drive unit from the drive train. There is thus always the possibility in an emergency to prevent further propulsion of the vehicle.

Preferably, the control valve and the check valve are arranged in an at least partially two-channel hydraulic line and each of the two valves is associated with one of the two channels. For example, the hydraulic line can be structured in such a way that at least in some sections a second channel represents a bypass to a first channel. Here, the control valve is provided in one of the channels for delaying the return flow of the hydraulic fluid and the check valve in the other channel to allow unimpeded flow in the opposite direction.

According to one embodiment, the above-described means for detecting a clutch signal include a clutch sensor associated with the clutch encoder element. By means of the coupling sensor can be determined in a simple and reliable manner, the position of the coupling element and the corresponding information of the control unit are provided. A clutch signal can thus be generated when moving the clutch encoder element, in particular when reaching or passing defined positions, such as end positions or a Einkuppelpunktes.

In addition, the clutch release system may comprise a displacement sensor associated with the clutch slave element for determining a current travel position of the clutch slave element. It is thus possible to determine the exact instantaneous position of the Kupplungsnehmerelements and to provide the appropriate information to the control unit. In response, the control unit may appropriately control the control valve, taking into account known engagement points and end points, and correspondingly control a closing operation of the clutch for a clutch closure. The control unit can thus determine a remaining travel distance of an opened clutch up to a stored engagement point and, taking into account a remaining time still required for (further) starting up or switching on the drive unit, regulate a flow rate of the control valve and, if necessary, adjust it in real time. A closing of the clutch or engagement can therefore be dynamically delayed and compensate for any varying on-times of an engine.

The control unit may consider a plurality of vehicle parameters for carrying out the method described and for regulating the control valve. For example, as described, the position of the coupling element, the position of the Kupplungsnehmerelements and also the current vehicle speed can be considered. In addition, a position of the accelerator pedal, said detection of an engaged gear and a current speed of the drive unit can be included in an evaluation of the control unit. In particular, the instantaneous speed, vehicle speed, accelerator pedal position and gear selection are used here for determining an admissible closing speed of the clutch by regulating the flow rate of the control valve, since these parameters influence a current operational readiness of the drive unit. If the engine speed and / or the vehicle speed is low and / or a high gear and / or a weak accelerator pedal operation is selected, a correspondingly slow closing of the clutch must be performed by regulating the control valve in order to prevent the described stalling of the drive unit. In the reverse cases, however, a faster closing of the clutch can be provided.

Preferably, an internal combustion engine is used as the drive unit.

The invention will be explained in more detail with reference to the accompanying drawings. Showing:

1 a flowchart for the sequence of the described method,

2 a schematic arrangement of a starting control device according to the invention and

3 a schematic arrangement of a controller according to the invention for the arrangement according to 2 ,

1 shows a flowchart for the sequence of the method according to the invention. A prerequisite for carrying out the method according to the invention for controlling an automatic startup operation of a drive unit (AE) of a motor vehicle is that the vehicle or the drive unit is in a standby state with the drive unit switched off. This means that the drive unit of the vehicle has already been switched over in a preceding step by an engine start-stop system from a normal operating state with the drive unit switched to the standby state with the drive unit switched off. So is the vehicle in the ready state 11 is monitored in the context of the process, whether a connection condition for renewed connection of the drive unit and change to the normal operating state is present. This is done in a monitoring step 12 monitors a shift position of a vehicle transmission and detects whether a gear is engaged as shift position. If this is not the case, the vehicle remains in the ready state. In addition, in a further monitoring step 13 a clutch signal of a clutch encoder element monitors and detects whether a clutch signal has been generated for closing an open clutch of the vehicle. If this is not the case, the vehicle remains in the ready state. The two monitoring steps 12 . 13 can be done both sequentially in any order and at the same time contrary to the illustrated embodiment.

On the other hand lead both monitoring steps 12 . 13 to a positive result, so there is a start of the drive unit 14 and a closing operation for closing the opened clutch of the vehicle 15 , This is a delay 16 the closing operation so that sufficient time is provided to the started drive unit to start up and change to an appropriate operating condition. Gives a check 17 the drive unit, that this is ready for operation and thus in a defined and suitable operating state, ie the normal operating state with the drive unit is switched on, it can be a clutch engagement 18 respectively. This can be done, for example, as a partial coupling closure by closing the coupling up to a defined coupling point of the coupling or by a complete coupling connection. Passes the review 17 on the other hand negative, then the delaying of the closing process becomes 16 continued and the review 17 repeated.

2 shows a schematic arrangement of a starting control device according to the invention 20 with a clutch transmitter element 21 , This may include, for example, a clutch master cylinder with a clutch pedal operatively coupled (both not shown). The coupling element 21 is via a hydraulic line 23 with a Kupplungsnehmerelement 22 operatively coupled. The clutch slave element 22 For example, it may include a clutch slave cylinder for actuating a clutch release (both not shown). So is the clutch encoder element 21 operated, so flows by means of the hydraulic line 23 a hydraulic fluid (not shown) to the clutch slave element 22 to the clutch slave element 22 to press. Will the clutch transmitter element 21 no longer actuated, the hydraulic fluid flows in the reverse direction back to the clutch encoder element 21 ,

The hydraulic line 23 has in the illustrated embodiment, a branched region in which the hydraulic line in two channels 26 . 27 branched. In a first channel 26 is a check valve 24 arranged such that the hydraulic fluid in one direction only from the clutch encoder element 21 to the clutch slave element 22 can flow. A reflux in the first channel 26 is through the check valve 24 blocked. The hydraulic fluid can thus only via a second channel 27 to the clutch transmitter element 21 flow back. In the second channel 27 is a control valve 25 which is configured to reduce a flow velocity of the hydraulic fluid and thus to delay the movement of the hydraulic fluid. In this way, a resetting or relieving the Kupplungsnehmers be delayed, so that as a result, a closing of an open clutch of the vehicle or a clutch closure is also delayed. Of course, the control valve 25 be executed controllable, with a corresponding control in 3 is shown.

3 shows a schematic arrangement of a control according to the invention for a starter control device 20 to 2 , This includes a control unit 31 , which communicates with the control valve 25 (see. 2 ) is connected so as to regulate or vary the flow rate of the returning hydraulic fluid. As input variables for this control of the control valve 25 For example, in the illustrated embodiment, the controller may be set to a position as needed 33 the coupling element ( 2 : 21 ), a position 34 of the clutch slave element ( 2 : 22 ), a current vehicle speed 35 , a position 36 an accelerator pedal of the vehicle, a detection 37 an engaged gear and a current speed 38 to fall back on the drive unit. About the position 33 the coupling element 21 can be determined how far the driver wants to keep the clutch open. Due to the delay of the hydraulic fluid flow via the control valve 25 corresponds to the position 33 However not inevitably also the position of the Kupplungsnehmerelementes, which is possibly further opened due to the delay of the control valve.

The current vehicle speed 35 and the position 36 the accelerator pedal as well as the detection 37 the engaged gear and the current speed 38 allow the control unit to determine whether there is already an operating state of the drive unit, in which a coupling or a complete coupling of the clutch can be allowed. It can therefore be determined as a function of several parameters, whether the drive unit is sufficiently resilient in its current operating state, or a stalling of the drive unit is to be feared. In the latter case, engagement must be further delayed in order to enable the device to reach an operational state of operation and only then to engage it.

Of course, in addition to the parameters mentioned, additional parameters may additionally or alternatively be taken into account by the control unit.

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 102004024212 A1 [0006, 0008]

Claims (8)

Method for controlling an automatic startup operation of a drive unit of a motor vehicle, wherein the motor vehicle comprises an automatic start / stop system for switching between a normal operating state with the drive unit switched on and a standby state with the drive unit switched off, wherein in the standby state a clutch signal of a clutch transmitter element ( 21 ) And also a shift position of a vehicle transmission is monitored and a first defined start condition for automatically turning on the power unit is switched off, when a gear engaged position and simultaneously a clutch signal for closing an open clutch of the vehicle is detected, characterized in that a partial or complete clutch closure to close the clutch is delayed until the automatically started drive unit is ready. Method according to claim 1, wherein the coupling element ( 21 ) comprises a clutch master cylinder with a clutch pedal operatively coupled and generating the clutch signal to close the open clutch by releasing the pedal pedal has occurred. Start control device for controlling an automatic startup operation of a drive unit of a motor vehicle with - a clutch release system ( 20 ) for actuating the clutch of the vehicle and - means for monitoring and detecting a clutch signal of the clutch release system and - means for detecting a shift position of a vehicle transmission and - a control device which is adapted to carry out a method according to claim 1 or 2 and at least partially controlling the start control device characterized in that the starter control device further comprises delay means for selectively delaying the partial or full clutch closure to close the clutch until the automatically started drive unit is operational. A starting control device according to claim 3, wherein the clutch release system - A hydraulic clutch encoder element with a clutch master cylinder for pressurizing a hydraulic fluid and A clutch slave element comprising a clutch slave cylinder for actuating a clutch release, wherein the clutch master cylinder and the clutch slave cylinder are operatively coupled via a hydraulic line having the hydraulic fluid, characterized in that the delay means comprises a control valve for delaying backflow of the hydraulic fluid from the clutch slave cylinder to the clutch master cylinder. The startup control apparatus of claim 4, wherein the clutch release system further comprises a check valve disposed parallel to the control valve and oriented so that the hydraulic fluid through the check valve can flow from the clutch master cylinder to the clutch slave cylinder at any time, thus enabling actuation of the clutch slave cylinder at all times. The start control device according to claim 5, wherein the control valve and the check valve are arranged in an at least partially two-channel hydraulic line and each of the two valves is associated with one of the two channels. A starting control device according to any one of claims 3 to 6, wherein the means for detecting a clutch signal comprises a clutch sensor associated with the clutch encoder element. The start control device according to any one of claims 3 to 7, wherein the clutch release system comprises a displacement sensor associated with the clutch slave element for determining a current travel position of the clutch slave element.

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