DE102013200946A1 - Method for operating motor vehicle by using stepped automatic transmission, involves executing clutch start by pressing adjusting elements from sailing operation, and initiating termination of sailing operation - Google Patents

Abstract

The method involves providing a combustion engine, a stepped automatic transmission (300) with multiple adjusting elements (302,304,306,308,310) and a device for providing actuating energy (312). A clutch start is executed by pressing adjusting elements from a sailing operation, and initiating the termination of the sailing operation. The adjusting element is terminated by the actuation of the sailing operation. An independent claim is included for a stepped automatic transmission.

Description

The invention relates to a method for operating a motor vehicle and to an arrangement for carrying out the method.

State of the art

As sailing, a driving condition is referred to in motor vehicles, which is already known in hybrid vehicles, such as, for example, in a parallel hybrid with separating clutch between the engine and electric drive machine. However, this is also useful for conventional vehicles.

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. To save fuel, 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 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.

On the other hand, the engine used in engine-stopped sailing must have a near-stop start-stop function compared to a pure start / stop vehicle. H. running at less than 3 to 5 km / h, be started about two to three times more often. This leads to higher requirements, especially in the electrical system and the starter system and possibly the transmission.

The above-mentioned requirement for starter load, in particular with regard to the number of cycles, can no longer be met with a standard starter, such as, for example, a brushed starter system. This provides that the starter is used as the only starting means. It should also be noted that the starter noise is perceived as disturbing for frequent starts for the driver and the starter voltage drops in the electrical system. It is therefore proposed, the engine instead of the conventional starter system when the vehicle is in sailing mode, in most cases by means of the clutch of an automatic transmission, such as. An automatic transmission, continuously variable transmission, dual-clutch transmission and automated manual transmission, or by means of an automated clutch in To connect to a manual transmission by starting a clutch.

In this way, a reduction in the load by the number of starts of the mechanical starter system, which is conventionally equipped with brush-commutated starter can be achieved. Thus, additional measures, service concepts or use of alternative starting systems, such as, for example, a belt starter generator, which leads to additional costs, can be avoided. Furthermore, voltage dips during startup are avoided, which reduces the requirements for the electrical system.

An already known starting method consists in a start via a clutch slip. The defined closing clutch slipping the internal combustion engine to speed. The disadvantage here is that the entire starting energy is taken from the kinetic energy of the vehicle, which can lead to a possibly noticeable delay, which is perceived by inmates as uncomfortable. This can be avoided with an annoying direct start, which corresponds to a clutch-assisted direct start or a clutch start.

Here, in the internal combustion engine, in particular in a direct injection, in which the position is known by a discharge detection, injected into the first cylinder, which is in the compression stroke, and rotated with a correspondingly complex control of the clutch, the engine only over the first top dead center , The engine then starts by itself, the clutch can be easily reopened so that the repercussions, namely jerk and torque jumps are minimized to the drive train and thus to the driver. After the engine has reached a defined speed, the clutch is closed again.

The method can be supplemented in a direct-injection internal combustion engine with an injection and ignition in the stationary internal combustion engine, d. H. Cylinders in the power stroke, combine or transferred to a naturally aspirated engine. In addition, in the naturally aspirated engine, methods for starting at the first top dead center are known.

In this way, a very comfortable, jerk-free, quiet and fast start is possible. Initial measurements in a twin-clutch gearbox and automated clutch handset show that implementation is possible at speeds in excess of 30 km / h. There is one, however lower speed threshold at which the clutch start is no longer comfortable.

A hybrid vehicle already has the necessary conditions for sailing. In a conventional vehicle starter system, electrical system, steering, braking system and transmission must be adapted to the additional requirements.

Some types of transmissions are already usable for the sailing without further measures, such as electro-mechanical or electro-hydraulically actuated dual-clutch transmission or automated manual transmission.

In particular, conventional stepped automatic transmission with converter require additional measures and special control methods to perform a sailing or a comfortable clutch start.

A method for operating a motor vehicle is, for example, from the document DE 10 2007 035 424 A1 in which a driver can individually select whether the motor vehicle is sailing. For sailing, a clutch of the vehicle is automatically operated and the engine is stopped. At the end of the sailing, the combustion engine is started automatically and the clutch is automatically actuated.

Disclosure of the invention

Against this background, a method according to claim 1 and a stepped automatic transmission with the features of claim 7 are presented. Embodiments result from the dependent claims and the description.

• 1. Eine von dem Verbrennungsmotor-Zustand bzw. von der Verbrennungsmotor-Drehzahl unabhängige Energiequelle zur Betätigung der Betätigungselemente bereitzustellen. Dies kann bei einer hydraulischen Steuerung bspw. eine elektrische Zusatz-Ölpumpe sein oder bei zukünftigen Systemen ein Hydraulik-Speicher, ein sogenanntes Powerpack, nämlich elektrische Pumpe mit Speicher und ggf. Ventil, oder eine elektromechanische Betätigungseinrichtung.
• 2. Die hydraulische Steuerung hinsichtlich Dynamik der Betätigungselemente zu verbessern, bspw. durch Optimierung der Volumenströme, oder der vollständige oder teilweise Ersatz durch bspw. elektro-mechanische Betätigungseinrichtungen.
• 3. Die Anzahl der am Steuerungsverfahren beteiligten Stellelemente sinnvoll zu begrenzen und nur diese gezielt auf die durch das Verfahren sich ergebenden Anforderungen auszulegen und ggf. zu verstärken.

There are thus additional measures and a control method of the internal control elements of a stepped automatic transmission, combined with control of the control elements of the internal combustion engine to perform a sailing and a comfortable clutch start presented. In this case, an advantageous combination is expediently chosen, with which costs can be minimized. It is proposed in embodiments:

• 1. Provide an independent of the engine state or the engine speed energy source for actuating the actuators. This may be in a hydraulic control, for example, an additional electric oil pump or future systems, a hydraulic accumulator, a so-called power pack, namely electric pump with memory and possibly valve, or an electromechanical actuator.
• 2. To improve the hydraulic control in terms of dynamics of the actuators, eg. By optimizing the flow rates, or the complete or partial replacement by, for example, electro-mechanical actuators.
• 3. To meaningfully limit the number of control elements involved in the control process and to interpret and, if necessary, only strengthen these specifically for the requirements resulting from the process.

To perform the clutch start at least one actuator, eg. A clutch and / or a brake is used. In an embodiment, exactly one actuator is used. When starting can be accelerated by pressing, for example. Close, an actuating element of the engine. Upon reaching predetermined criteria, the actuator can be disabled again, eg. Open, be. One criterion may be the speed. It should be noted that the speed is typically only an input variable or a criterion until the actuator is opened again. The clutch start works regularly only in connection with a gear / clutch activation and engine interventions, for example. Injection in compression, ignition after starting, further injection / ignition in free run-up, adjusting a target speed or a target torque, etc.

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 an embodiment of an automatic transmission.

2 shows a further embodiment of an automatic transmission in a schematic representation.

3 shows a transmission with assignment of actuated actuator to selected gear.

4 shows phases during the course of the presented process.

5 shows subsequent phases during the course of the presented process

6 shows a stepped automatic transmission.

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 is a perspective view of an automatic transmission, in total with the reference numeral 10 is reproduced according to the prior art. The illustration shows a torque converter 12 , a gear pump 14 , a clutch 16 , a brake 18 , a planetary gear set 20 , a parking lock 22 and a mechatronics module 24 , A first arrow 26 illustrates the drive, a second arrow 28 illustrates the downforce.

An automatic transmission, like this in 2 is shown, regularly includes a converter 50 with lockup clutch 52 to minimize the converter slip and the losses associated therewith, a mechanical pump driven by the transmission input shaft 54 , which serves as an oil pump, the actual planetary gear sets 56 for setting the transmission ratio or the neutral gear or reverse gear by means of actuators 58 , such as couplings 60 and brakes 62 , a parking lock 64 and a hydraulic control (dashed line 80 ), which the adjusting elements 58 actuated by means of electrically operated valves.

The illustration also shows a selector lever 66 , a differential axle drive 68 , a control unit 70 and an internal combustion engine 72 , The combination of the controlled adjusting elements results in the gear ratio.

In 3 is a gearbox with associated switching stages is shown. The gear 100 includes a controlled torque converter lockup clutch 102 , a converter 104 , a clutch A 106 , a clutch B 108 , a clutch E 110 , a brake C 112 , a brake D 114 , a planetary gear set 116 and a freewheel 118 ,

In a mapped table 120 is in a first column 122 the selected gear is indicated, R stands for the reverse gear. In the next columns, for control elements, it is indicated whether it is closed, which is indicated by a filled circle, or closed, which is indicated by a missing entry. An unfilled circle indicates a choice depending on the operating condition. An asterisk indicates a status depending on the circuit program. In a second column 124 are states of the lockup clutch 102 shown. In a third column 126 are states of clutch A 106 shown. In a fourth column 128 are states of clutch B 108 shown. In a fifth column 130 are states of clutch E 110 shown. Thus, in the second to fifth column states of couplings 131 clarified.

In a sixth column 132 are conditions of brake C 112 and in a seventh column 134 Conditions of the brake D 114 clarified. The sixth column 132 and the seventh column 134 show thus states of brakes 137 at. An eighth column 136 shows states of freewheeling 118 , A new column 138 shows the respective gear ratio.

To set the first gear, the clutch A must 106 and the brake D 114 be closed. In the illustration of the power flow or the wheelsets involved is shown, which then give the translation.

In a gear change, eg. From the first to the second gear, a rule is kept closed in the rule, in this case, the clutch A. 106 , and an actuator in a cross-over circuit, in this case the brake D 114 to the brake C 112 ,

• 1. Durch die mechanisch angetriebene Getriebepumpe liegt kein Druck an, somit ergibt sich kein Volumenstrom während des Segelns. Aus diesem Grund ist die Aktuierungsenergie für Stellelemente und damit die Kühlung bzw. Schmierung der Komponenten nicht sichergestellt.
• 2. Es kommt zu Einschränkungen bei der Kupplungs-Regelungsgüte und Leistungsfähigkeit der Kupplung infolge einer indirekten Ansteuerung sowie bei hydraulischen Sicherheitskonzepten mit Magnetventil und mechanischem Verstärkungsschieber, in der Regel mit Füll-/Entleer-Drosseln, und bei hydraulischen Sicherheitskonzepten, wie bspw. bei kundenspezifischen Notlaufprogrammen mittels Schiebeventilen. Zudem ist die Wandlerüberbrückungskupplung im Vergleich zu einer Gangkupplung ggf. weniger leistungsfähig.
• 3. Der Einfluss hydrodynamischer Wandler in Verbindung mit dem Schaltablauf für ein Segeln bzw. einen Kupplungsstart durch die Aktuierung der Gangkupplungen und Bremsen sowie der Wandlerüberbrückungskupplung ist zu beachten. Das Drehmoment kann prinzipiell von den Rädern in Richtung Motor bzw. einer Turbine auf Pumpenseite übertragen werden. Ein Momenten- bzw. Drehzahlaufbau erfolgt auch hier sehr schnell, nämlich abhängig von Befüllgrad, und ist kaum zu beeinflussen. Dies stört einen gezielt gesteuerten Drehmomentenaufbau beim Kupplungsstart über die Wandlerüberbrückungskupplung.
• 4. Die Kupplungen und Bremsen als Stellelemente des Getriebes sind nicht auf die zusätzlichen Belastungen durch den Kupplungsstart ausgelegt.

By the in 3 The following problems arise for the sailing and the coupling start:

• 1. There is no pressure due to the mechanically driven gear pump, so there is no volume flow during sailing. For this reason, the Aktuierungsenergie for adjusting elements and thus the cooling or lubrication of the components is not guaranteed.
• 2. There are limitations in clutch control performance and clutch performance due to indirect control, as well as in hydraulic safety concepts with solenoid valve and mechanical boost valve, typically with charge / discharge chokes, and in hydraulic safety concepts such as customer-specific Emergency running programs by means of slide valves. In addition, the lockup clutch may be less powerful compared to a speed clutch.
• 3. The influence of hydrodynamic converters in connection with the shifting sequence for sailing or a clutch start by the actuation of the gear clutches and brakes as well as the lockup clutch must be considered. The torque can in principle be transferred from the wheels in the direction of the engine or a turbine on the pump side. A torque or speed build-up is also very fast here, namely depending on the degree of filling, and is hardly to influence. This interferes with a specifically controlled torque build-up when starting the clutch via the torque converter lockup clutch.
• 4. The clutches and brakes as control elements of the gearbox are not designed for the additional loads caused by starting the clutch.

In the context of the described method, it is proposed to equip the stepped automatic transmission, for example, with an electric auxiliary oil pump (ELOP) or a hydraulic accumulator, which addresses the first problem point. Thus, there is provided a means for providing set energy, which operates independently of the state or of the rotational speed of the internal combustion engine. It should be noted that it is limited, for example, in terms of packaging and electrical performance due to high transmission system leakage, etc. By packaging is meant the allowable size of the component that must be accommodated in the existing driveline around the transmission and engine. Therefore, further measures to meet demand and significant reduction of the leakage may be necessary, which may lead to a revision of the hydraulic, for example. Leakage reduced rotary joints, improved sealing technology, etc.

Furthermore, the performance of the control must be improved, which may be achieved with solenoid valves that can operate the clutches without amplifier shifter, if necessary. This takes into account the second problem.

It is also conceivable to replace the hydraulic control completely or partially by means of other operating principles, for example by electro-mechanical actuators.

With regard to problem points 3 and 4, replacement of the converter by a starting clutch and carrying out the coupling start with this element can be considered. However, this could possibly lead to reduced comfort, which may not be accepted by the customer.

In principle, it is conceivable to carry out a clutch start with the torque converter lockup clutch. When changing from driving to sailing, an adjusting element of the current gear is then internally opened, so that no torque is transmitted to the converter. When restarting, you must first change internally to the appropriate gear. Accordingly, the first or second actuator must be closed. Then the traction is made to the transducer by the last actuator is actuated or aktuiert. Finally, the clutch start is realized via the torque converter lockup clutch. The prerequisite for this is a small influence by the transducer, i. the torque / speed build-up on the converter is slow, to the clutch torque. If necessary, this can be achieved by adapting the converter. In addition, the adaptation of the lockup clutch, i. H. the adjustment of the control and the mechanics, necessary. Therefore, such a procedure seems to be of little use.

• 1. für ein Getriebe, das als Stand der Technik bezeichnet wird mit mechanischer Ölpumpe, Wandler und zusätzlicher elektrischer Ölpumpe,
• 2. für eine Fahrsituation als Kombination aus Geschwindigkeit, Gang, Fahrzustand, bspw. Ausrollen, und weitere,
• 3. für eine spezielle Motorstart-Strategie, nämlich Direktstart mit Einspritzung in Kompressionstakt/Zündung nach Erreichen des ersten oberen Totpunkts. 4 und 5 zeigen unterschiedliche Phasen beim Ablauf des vorgestellten Verfahrens, nämlich Fahren 150, Segeln einleiten 152, Segeln 154, Kupplungsstart 156 und Weiterverfahren 158.

It has been recognized that the constraints imposed by the transducer can be properly circumvented by operating the actuators. Therefore, the following procedure is proposed, which exemplifies the method:

• 1. for a transmission which is referred to as state of the art with mechanical oil pump, converter and additional electric oil pump,
• 2. for a driving situation as a combination of speed, gear, driving condition, for example. Rolling out, and further,
• 3. for a specific engine start strategy, namely direct start with injection in compression stroke / ignition after reaching the first top dead center. 4 and 5 show different phases in the process of the presented method, namely driving 150 To initiate sailing 152 , Sailing 154 , Clutch start 156 and proceeding 158 ,

Furthermore, gradients are displayed, namely a first course 162 for the speed, a second course 164 for the position of the accelerator, a third course 166 for the speed of the engine, a fourth course 168 for the state of ELOP, a fifth course 170 for the state of the lockup clutch, a sixth course 172 for the state of the clutch A, a seventh course 174 for the clutch B and an eighth course 176 for the condition of the clutch E.

In the phase 150 Driving is here exemplarily chosen the fifth gear. The ELOP is switched off, the supply takes place by means of a mechanical oil pump. The torque converter lockup clutch and the clutches B and E are closed. The one with 200 designated gear state illustrates this.

In the second phase 152 Initiate sailing the driver goes off the gas, the ELOP is turned on, the drive train is disconnected. The lockup clutch and clutch B remain closed. The clutch E is opened. The engine is switched off, the target cylinder for the first injection, typically in the compression stroke, which is known by the discharge position is determined. The one with 202 designated gear state illustrates this

In the third phase 154 a change to onward journey takes place, in this case in fourth gear. For this purpose, the clutch B opens, at the same time closes the clutch A. The with 204 designated gear state illustrates this.

Furthermore, as now in 5 can be seen, the ELOP is on. The lockup clutch and the clutch A are closed. The one with 206 designated gear state illustrates this.

Subsequently, in the fourth phase 156 Clutch start, that the driver goes to the gas pedal. There is a direct start method by injection into the compression stroke. The combustion parameters are determined by the start position of the relevant cylinder for the direct start. The clutch E closes to turn the engine. Subsequently, the clutch E opens again, there is a free engine startup. After reaching the predetermined speed threshold, the clutch E closes again. The one with 208 designated gear state illustrates this.

Finally, in the phase 158 Continue moving the ELOP off and the mechanical pump delivering the required pressure. This example continues in fourth gear. Clutches B and E are closed.

During sailing, only necessary control elements of the current gear, in this case the lockup clutch and in fifth gear the clutch B, remain closed so that no torque is transmitted to the converter.

In this embodiment, there is a limitation on the available starting gears 4 . 5 . 6 so that clutch E can always be used as a clutch start control clutch. This is done in conjunction with the closed second clutch or brake, namely in the fourth gear the clutch A, in the fifth gear the clutch B and in the sixth gear the brake C. The restriction to the gears 4 . 5 and 6 has the advantage that always the same control element, in this case the clutch E, can be used. Of course, it is also possible to use other control elements. Conveniently, however, exactly one actuator is selected, since in this case only one actuator must be designed for the described method. The choice of gears 4 . 5 and 6 is appropriate, since in upper gears a clutch start is relevant and comfortable.

If it is found during sailing that the speed is too low for the selected gear, then a lower gear can be selected when restarting by actuating actuators.

At the in 4 and 5 As shown embodiment, a restart takes place solely by the coupling, without any limitation is given by the converter torque build-up. Therefore, it is precisely this control element can be designed specifically to meet the increased requirements and adapted without further elements need to be adjusted, which is advantageous in terms of cost. This adaptation can be done by a special mechanical design of the clutch E. These further measures may take into account additional life requirements due to the method described. In particular, the number of actuation, the actuation forces, the wear, the introduction of thermal load during engagement during the coupling start are taken into account.

Similar strategies can be applied to older 5-speed or new 7- / 8- / 9-speed transmissions.

6 shows a stepped automatic transmission with eight gears, the total with the reference numeral 300 is designated. The illustration shows a brake A as adjusting elements 302 , a brake B 304 , a clutch C 306 , a clutch D 308 and a clutch E 310 , Furthermore, purely schematically is a device for providing job energy 312 played. This may, for example, be designed as an additional electric oil pump or as a storage element.

In a table 320 is in a first column 322 the selected gear, in a second column 324 the state of the brake A 302 in a third column 326 the state of the brake B 304 in a fourth column 328 the condition of the clutch C 306 in a fifth column 330 the condition of the clutch D 308 and in a sixth column 332 the state of the clutch E 310 whether it is open, no entry, or closed, indicated by a solid circle, is displayed.

In a seventh column 340 is the respectively assigned gear ratio and in an eighth column 342 the gear jump entered.

The method will now be explained with reference to an example in which to drive in seventh gear, followed by sailing and finally driving on in fifth gear.

In the illustrated stepped automatic transmission 300 it is expedient for the initiation of the sailing phase only in the neutral gear by closing the brakes A. 302 and B 304 switch. But it may also be sufficient in this configuration, in the higher gears, for example. Gears 4 to 8th to open only the element D and keep the other two elements of the respective adjacent passage closed, so z. B. at previous 7 , Just walk the elements A 302 and C 306 to keep closed.

To make a clutch start after sailing, you will then first select the appropriate gear, namely brake B 304 and clutch C 306 close and clutch D 308 still open. The clutch start is with the clutch D 308 executed.

It should also be considered that extensions in connection with the injection, for example in the expansion stroke with the engine stopped, in order to minimize a necessary clutch torque when arriving, are possible.

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 102007035424 A1 [0015]

Claims (10)

Method for operating a motor vehicle, which via an internal combustion engine and a stepped automatic transmission ( 300 ) with a number of actuating elements ( 302 . 304 . 306 . 308 . 310 ) and a device for providing job energy ( 312 ), wherein by actuating at least one of the actuating elements ( 302 . 304 . 306 . 308 . 310 ) From a sailing operation, a clutch start executed and termination of the sailing operation is initiated. Method according to Claim 1, in which precisely one actuating element ( 302 . 304 . 306 . 308 . 310 ) is provided, by the operation of the sailing operation is terminated. Method according to Claim 1 or 2, in which the actuation of at least one of the actuating elements ( 302 . 304 . 306 . 308 . 310 ) in connection with a sequence of interventions on the engine. Method according to one of claims 1 to 3, wherein before completion of the sailing operation in dependence of the speed of the motor vehicle at least one actuating element ( 302 . 304 . 306 . 308 . 310 ) to select a speed-adapted gear. Method according to one of claims 1 to 4, wherein the internal combustion engine by closing at least one actuating element ( 302 . 304 . 306 . 308 . 310 ) is accelerated and reopened after reaching predetermined criteria. The method of claim 5, wherein one of the criteria is the speed of the internal combustion engine. A stepped automatic transmission, in particular for carrying out a method according to one of Claims 1 to 6, having a number of actuating elements ( 302 . 304 . 306 . 308 . 310 ) and a device for providing job energy ( 312 ), wherein at least one of the adjusting elements ( 302 . 304 . 306 . 308 . 310 ) is designed to end a sailing operation. A stepped automatic transmission according to claim 7, wherein exactly one actuating element ( 302 . 304 . 306 . 308 . 310 ) is designed to terminate the sailing operation. A stepped automatic transmission according to claim 7 or 8, wherein the means for providing point energy ( 312 ) is designed as an additional electric oil pump. A stepped automatic transmission according to claim 7 or 8, wherein the means for providing point energy ( 312 ) is designed as a memory element.

Images