DE102019007231A1 - Method, computer program and control unit for accelerating a motor vehicle with acceptable wear for the vehicle clutch - Google Patents

Abstract

A motor vehicle driveline (V) accelerates the vehicle (V) from an initial speed (v) to a target speed (v) in response to a set of input parameters (v, v, m, F, L). In particular, a minimum acceleration (a) is determined, which is required in order to achieve the desired speed (v) with an acceptable wear for the clutch (125) of the vehicle (V). The minimum acceleration (a) is determined based on the set of input parameters, which include a driving resistance (F) for the vehicle (V), a weight (m) of the vehicle (V), a maximum amount of energy (L), which is generated by the clutch ( 125) is absorbable, and comprises a speed difference (Δv) between the initial and the desired speed (v, v). A control signal (S) controls the powertrain (120) to cause the vehicle (V) to accelerate from the initial speed (v) to the target speed (v) at least as fast as specified by the minimum acceleration (a).

Description

TECHNICAL AREA

The invention relates generally to automatic speed control for motor vehicles. In particular, the present invention relates to a method for accelerating a motor vehicle, a powertrain control unit that implements the present method, and a vehicle that includes the powertrain control unit. The invention also relates to a computer program product and a non-volatile data carrier.

BACKGROUND

In the case of autonomously controlled vehicles, it is customary to accelerate relatively quickly from a standstill in order to minimize wear on the clutch of the vehicle. If the vehicle is transporting passengers, however, such acceleration can be experienced as uncomfortable by the passengers. A gentler acceleration would be preferable. However, this causes greater wear on the clutch and makes it difficult to determine suitable maintenance intervals for the clutch.

The US 2013/0281260 discloses systems and methods for a supported direct start control. An example method varies engine torque, forward clutch engagement pressure, and wheel brake pressure during vehicle launch in response to a longitudinal vehicle gradient to improve vehicle launch performance.

• - Bestimmen aus dem notwendigen Motordrehmoment für den Motor einer notwendigen Motordrehzahl zum Erreichen des angefragten Kupplungsdrehmoments;
• - Anheben der Motordrehzahl auf die notwendige Motordrehzahl, falls die notwendige Motordrehzahl größer als eine vorbestimmte Motordrehzahl ist.

The WO 2010/047652 describes a method for speed control of an engine of a motor vehicle with an automatic transmission when engaging a clutch of the vehicle when the vehicle is started. The method includes: - requesting a desired clutch torque; - determining a current clutch torque of the clutch and a closing rate for the clutch when engaging the same; Determining a dynamic torque increase required to provide the increase in engine speed required when the clutch is engaged at the engagement rate; Determining, based on parameters that include the current clutch torque and the dynamic torque increase, a necessary engine torque to achieve the requested clutch torque;

• - Determining from the necessary engine torque for the engine a necessary engine speed to reach the requested clutch torque;
• - Raising the engine speed to the necessary engine speed if the necessary engine speed is greater than a predetermined engine speed.

Various solutions are therefore known for controlling motor vehicles so that they accelerate automatically. However, there is still no method that ensures that the clutch does not experience too much wear.

SUMMARY

It is therefore an object of the present invention to provide an improved solution for accelerating a motor vehicle to a desired speed while the clutch is gradually being engaged so that the clutch can be fully engaged at a desired speed.

According to one aspect of the invention, this object is achieved by a method which is carried out in a drive train control unit, the method requiring the acceleration of a motor vehicle from an initial speed, for example from a standing position, to the desired speed. A set of input parameters is achieved in the powertrain control unit; and based on the set of input parameters, the control unit controls the vehicle to accelerate from the initial speed to the target speed. In particular, a processing circuit in the control unit determines a minimum acceleration that is necessary to achieve the desired speed with an acceptable wear for a clutch in the vehicle. The minimum acceleration is determined based on the set of input parameters, which includes vehicle drag, vehicle weight, maximum amount of energy that can be absorbed by the clutch, and a speed difference between the initial and target speeds. A control signal is generated that is configured to control a powertrain in the vehicle to cause the vehicle to accelerate from the initial speed to the target speed at least as fast as specified by the minimum acceleration.

The present method is advantageous because not only does it ensure that no more than an acceptable amount of energy is absorbed by the clutch, but the method also enables the clutch wear to be predicted very precisely. As a result, a maintenance schedule for the clutch can be drawn up very precisely.

According to one embodiment of this aspect of the invention, the minimum acceleration is determined in relation to the driving resistance and in a quadratic relationship with the speed difference.

wobei

• F_e der Fahrwiderstand ist,
• L die maximale Energiemenge ist, die mit Bezug auf den annehmbaren Verschleiß durch die Kupplung absorbierbar ist,
• Δv die Geschwindigkeitsdifferenz zwischen der anfänglichen und der angestrebten Geschwindigkeit ist, und
• m das Gewicht des Fahrzeugs ist.

The minimum acceleration is preferred, a _min , determined as: $${\text{a}}_{\text{min}}=\frac{{\text{F}}_{\text{e}}}{\frac{\text{2L}}{\Delta {\text{v}}^{\mathrm{2nd}}}-\text{m}},$$

in which

• F _e the driving resistance is
• L is the maximum amount of energy that can be absorbed by the clutch with respect to acceptable wear,
• Δv is the speed difference between the initial and the target speed, and
• m is the weight of the vehicle.

Therefore, an acceleration value can be calculated that represents a constant increase in speed from the initial speed to the desired speed and ensures that the clutch does not experience unnecessary wear.

According to another embodiment of this aspect of the invention, the maximum amount of energy that can be absorbed by the clutch is either a constant number or a variable parameter. In the former case, the constant number is set to an empirically verified size for the specific clutch; and in the latter case, the parameter is determined based on a current temperature of the clutch, a maintenance interval for the clutch and / or a fuel consumption condition. Therefore, the minimum acceleration can be calculated with even better precision.

According to yet another embodiment of this aspect of the invention, the driving resistance again includes: a road gradient factor, an air resistance parameter and / or a rolling resistance parameter. This enables dynamic and high-quality allocation of driving resistance. This also allows the minimum acceleration to be determined more appropriately.

According to yet another embodiment of the present aspect of the invention, the target speed is a maximum speed at which the clutch is fully engaged. In other words, the clutch can be fully engaged at a speed below the target speed. This is associated with even less clutch wear, but probably also a little less comfort for possible passengers in the vehicle.

According to a further aspect of the invention, the object is achieved by a computer program which contains instructions which, when executed on at least one processor, cause the at least one processor to carry out the method described above.

According to yet another aspect of the invention, the object is achieved by a non-volatile data carrier which contains such a computer program.

According to yet another aspect of the invention, the above object is achieved by a powertrain control unit adapted to be included in a vehicle to accelerate the vehicle from an initial speed to a target speed while the clutch is gradually engaged in the vehicle becomes. The powertrain control unit is configured to achieve a set of input parameters and control the vehicle based thereon to accelerate from the initial speed to the target speed. A processing circuit in the control unit is specifically configured to determine a minimum acceleration required to achieve the desired speed with acceptable clutch wear. The minimum acceleration is determined based on the set of input parameters, which includes a running resistance for the vehicle, a weight of the vehicle, a maximum amount of energy that can be absorbed by the clutch, and a speed difference between the initial and the target speed. The processing circuitry is further configured to generate a control signal configured to control the vehicle to accelerate from the initial speed to the target speed at least as fast as specified by the minimum acceleration. The advantages of this control unit as well as its preferred embodiments emerge from the above description with reference to the proposed method.

According to yet another aspect of the invention, the object is achieved by a vehicle that includes the proposed control unit for detecting errors in a driver support system of the vehicle.

Further advantages, favorable features and applications of the present invention will become apparent from the following description and the dependent claims.

Figure list

• 1 schematisch ein Fahrzeug in einer anfänglichen Position, wenn es mit einer anfänglichen Geschwindigkeit fährt, und zu einem späteren Zeitpunkt, wenn es mit einer angestrebten Geschwindigkeit fährt;
• 2 ein Blockdiagramm einer Antriebsstrangsteuereinheit gemäß einer Ausführungsform der Erfindung; und
• 3 anhand eines Ablaufschemas das allgemeine Verfahren gemäß der Erfindung.

The invention will now be described in more detail by means of preferred embodiments, which are disclosed as examples, and with reference to the accompanying drawings. Show it:

• 1 schematically illustrates a vehicle in an initial position when it is traveling at an initial speed and at a later time when it is traveling at a desired speed;
• 2nd a block diagram of a powertrain control unit according to an embodiment of the invention; and
• 3rd based on a flow chart, the general method according to the invention.

DETAILED DESCRIPTION

Forms on the left 1 schematically a motor vehicle V in an initial position when it is at an initial speed v ₀ moves. The vehicle is on the right V presented at a later date if it is at a desired speed v _t moves. Typically the initial speed v ₀ equals zero; and for a heavy motor vehicle, e.g. B. a truck or a bus is the target speed v _t given by the idling speed of the engine and the currently selected gear. However, any other values of the initial speed are in accordance with the invention v ₀ and the target speed v _t also conceivable as long as v _t > v ₀ .

The vehicle V has a powertrain that in 1 by the reference symbol 120 is shown. The drivetrain 120 contains the components of the drive train of the vehicle V between the transmission and the differential. The drivetrain 120 can thus comprise a drive shaft and a drive joint.

1 also symbolically shows a clutch 125 in the vehicle V , ie, a mechanical device configured to transfer power from the drive shaft of the engine to a driven shaft of the drive train 120 turn on and turn off.

The vehicle V also includes a powertrain control unit 110 based on a control signal S _ctrl is configured to cause the vehicle V from an initial speed v ₀ to a desired speed v _t accelerates while the clutch 125 is gradually indented. This is the powertrain control unit 110 configured to achieve a set of input parameters based on which acceleration is controlled.

Now with reference to 2nd a block diagram of the control unit 110 of the drive train according to an embodiment of the invention. The powertrain control unit 110 is preferred in one or more so-called ECUs (electronic control units) in the vehicle V implemented, these ECUs with other units, sensors and actuators in the vehicle V Exchange data and instructions via a CAN (control unit network) or an analog internal communication network.

The powertrain control unit 110 contains a processing circuit 112 and a non-volatile disk 114 that with the processing circuit 112 is communicatively connected. The non-volatile disk 114 again comprises a computer program product 115 , which contains software for performing the method described below when passed through the processing circuit 112 is performed. In response to control by the software is the processing circuit 112 specifically configured to a minimum acceleration amine to determine the speed needed to achieve the target v _t with acceptable wear for the clutch 125 to achieve if you are at the initial speed v ₀ starts.

If the clutch 125 used, ie indented and disengaged, it suffers from a certain physical loss of quality / deterioration. More specifically, rub during the clutch engagement process 125 , e.g. B. when starting from a standstill or in connection with a gear shift, various surfaces within the clutch 125 against each other in order to gradually transfer more power to the drive train and thus achieve comfortable and safe operation of the vehicle. Depending on the degree of friction of the surfaces against each other, the clutch suffers 125 more or less under the physical quality loss / deterioration. In the present disclosure, the term acceptable wear is intended to define how much of this friction can be tolerated so as not to wear the clutch too much 125 to cause and at the same time to achieve a comfortable and safe operation of the vehicle.

The processing circuit 112 determines the minimum acceleration amine based on the set of input parameters, which in turn is a driving resistance F _e for the vehicle V , a weight m of the vehicle V , a maximum amount of energy L , through the clutch 125 is absorbable, and a speed difference Δv between the initial and the target speed v ₀ and v _t contains. I.e. if the initial speed v ₀ is zero, the speed difference Δv equal to the target speed v _t . The maximum amount of energy L by the clutch 125 is absorbable, can basically be expressed by how much heat through the clutch 125 can be derived. As discussed below, this energy can be represented either by a constant number or by a dynamic parameter.

The driving resistance F _e is made up of any external causes that have a delaying effect on the locomotion of the vehicle V have together. Consequently, the driving resistance Fe include a road gradient factor (ie, a measure of a slope or slope), an air resistance parameter and / or a rolling resistance parameter.

After they have the minimum acceleration amine has determined, the processing circuit generates 112 the control signal S _ctrl that is configured to the vehicle V to control it from the initial speed v ₀ on the target speed v _t at least as fast as through the minimum acceleration amine given accelerated. In other words, acceleration is faster than the minimum acceleration a _min acceptable.

The desired speed is correspondingly according to one embodiment of the invention v _t the highest speed at which the clutch 125 should be fully indented. I.e. From the point of view of clutch wear, it is equally acceptable that the clutch is below the target speed at any speed v _t is fully engaged.

wobei

• F_e der Fahrwiderstand ist,
• L die maximale Energiemenge ist, die durch die Kupplung 125 absorbierbar ist,
• Δv die Geschwindigkeitsdifferenz zwischen der anfänglichen Geschwindigkeit v₀ und der angestrebten Geschwindigkeit v_t ist, und
• m das Gewicht des Fahrzeugs V ist.

The processing circuit is preferred 112 configured to the minimum acceleration a _min in relation to driving resistance F _e and in a quadratic relationship with the speed difference Δv to determine. More specifically, the minimum acceleration a _min be determined as: $${\text{a}}_{\text{min}}=\frac{{\text{F}}_{\text{e}}}{\frac{\text{2L}}{\Delta {\text{v}}^{\mathrm{2nd}}}-\text{m}},$$

in which

• F _e the driving resistance is
• L is the maximum amount of energy generated by the clutch 125 is absorbable,
• Δv the speed difference between the initial speed v ₀ and the target speed v _t is and
• m the weight of the vehicle V is.

According to one embodiment of the invention, the processing circuit is 112 configured to the maximum amount of energy L by the clutch 125 is treatable, either as a constant number or as a dynamic parameter.

If the maximum amount of energy L by the clutch 125 is absorbable, is regarded as a constant number, this number is preferably set to an empirically verified size, which takes into account the design of the coupling. Generally this means that for a large and relatively sturdy clutch L is comparatively high; and vice versa for a smaller and less robust coupling.

If the maximum amount of energy L by the clutch 125 is absorbable, is regarded as a dynamic parameter, this parameter can in turn be based on a current temperature of the clutch 125 , a maintenance interval for the clutch 125 and / or a fuel consumption condition can be determined. If, for example, the current temperature of the clutch 125 is already relatively high L set to a slightly smaller number than if the clutch temperature had been lower. The maintenance interval for the clutch 125 can influence the maximum amount of energy in such a way that L typically can be set to a higher value for a clutch with shorter maintenance intervals than for an identical clutch with less frequent maintenance opportunities. The fuel consumption condition can influence the maximum amount of energy in such a way that a lower allowed fuel consumption L lifts and vice versa.

In summary and with reference to the flow chart in 3rd Now, the general method according to the invention for accelerating a motor vehicle from an initial speed to a target speed while the clutch of the vehicle is gradually engaged will be described.

A first step 310 checks whether a set of input parameters has been received in the form of: a driving resistance for the vehicle, a weight of the vehicle, a maximum amount of energy that can be absorbed by the clutch, and a speed difference between the initial and the target speed. If the set of input parameters has been received, a step follows 320 ; and otherwise the process loops back and stays at step 310 .

In step 320 a minimum acceleration is determined, ie a smallest constant increase in speed from the initial speed to the desired speed. The minimum acceleration is determined based on the set of input parameters, for example in relation to the driving resistance, and in a quadratic relationship with the speed difference.

After that, in one step 330 generates a control signal configured to control a powertrain in the vehicle to cause the vehicle to accelerate from the initial speed to the target speed at least as fast as specified by the minimum acceleration.

The process then loops to step 310 back.

All process steps as well as each partial sequence of steps that are related to the above 3rd described, can be controlled using at least one programmed processor. Furthermore, although the embodiments of the invention described above with reference to the drawings include a processor and processes that are executed in at least one processor, the invention thus also covers computer programs, in particular computer programs on or in one Carrier suitable for putting the invention into practice. The program may be in the form of source code, object code, an intermediate code source, and object code, such as in a partially compiled form, or in any other form suitable for use in implementing the process of the invention. The program can either be part of an operating system or a separate application. The carrier can be any entity or device capable of carrying the program. For example, the carrier can be a storage medium, such as a flash memory, a ROM (fixed memory), for example a DVD ("Digital Video / Versatiie Disk"), a CD ("Compact Disc") or a semiconductor ROM, an EPROM ( erasable programmable read-only memory), an EEPROM (electrically erasable programmable read-only memory) or a magnetic recording medium, for example a floppy disk or a hard disk. In addition, the carrier may be a transferable carrier, such as an electrical or optical signal that can be transported over an electrical or optical cable or over radio or other means. If the program is embodied in a signal that can be transported directly via a cable or another device or other means, the carrier can consist of such a cable or such a device or such a means. Alternatively, the carrier can be an integrated circuit in which the program is embedded, the integrated circuit being suitable for execution or use in the execution of the processes in question.

The term “encompasses / encompasses” when used in the present description is intended to imply the presence of specified features, integers, steps or components. However, the term does not preclude the presence or addition of one or more additional features, integers, steps, or components or groups thereof.

The invention is not restricted to the described embodiments in the figures, but can vary freely within the scope of the claims.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• US 2013/0281260 [0003]
• WO 2010/047652 [0004]

Claims (17)

Method executed in a powertrain control unit (110) to accelerate a motor vehicle (V) from an initial speed (v ₀ ) to a desired speed (v _t ) while a clutch (125) in the vehicle (V) gradually The method includes: obtaining a set of input parameters (v ₀ , v _t , m, F _e , L), and controlling the vehicle (V) to accelerate from the initial speed to the target speed based on the Set of input parameters, characterized by determining, in a processing circuit (112) of the control unit (110), a minimum acceleration (a _min ) required to achieve the desired speed (v _t ) with acceptable wear for the clutch (125) reach, wherein the minimum acceleration (a _min ) is determined based on the set of input parameters, the driving resistance (F _e ) for the vehicle (V), a weight (m) of the vehicle (V) e maximum amount of energy (L) that is absorbable by the clutch (125) and includes a speed difference (Δv) between the initial and the target speed (v ₀ , v _t ), and generating a control signal (S _ctrl ) that configures to control a powertrain (120) in the vehicle (V) to cause the vehicle (V) from the initial speed (v ₀ ) to the target speed (v _t ) to be at least as fast as by the minimum acceleration given (a _min ) accelerates. Procedure according to Claim 1 , comprising determining the minimum acceleration (amine): in relation to the driving resistance (F _e ), and in a quadratic relationship with the speed difference (Δv). Procedure according to Claim 2 , comprising determining the minimum acceleration (a _min ) as: $$\frac{{\text{F}}_{\text{e}}}{\frac{\text{2L}}{\Delta {\text{v}}^{\mathrm{2nd}}}-\text{m}},$$

where F _{e is} the driving resistance, L is the maximum amount of energy that can be absorbed by the clutch (125), Δv is the speed difference between the initial and the target speed, and m is the weight of the vehicle (V). Method according to one of the preceding claims, wherein (L) the maximum amount of energy that can be absorbed by the coupling (125): is a constant number or based on at least one of a current temperature of the clutch (125), a maintenance interval for the clutch (125) and a fuel consumption condition. Method according to one of the preceding claims, wherein the driving resistance (F _e ) comprises at least one of: a road gradient factor, an air resistance parameter and a rolling resistance parameter. Method according to one of the preceding claims, wherein the desired speed (v _t ) is a highest speed at which the clutch (125) is fully engaged. Method according to one of the preceding claims, wherein the initial speed (v ₀ ) is zero. Computer program product (115) that can be loaded onto a non-volatile data carrier (114) that is communicatively connected to the processing circuit (112), wherein the computer program product (115) software for executing the method according to one of the Claims 1 to 7 when the computer program product (115) is executed on the processing circuit (112). Non-volatile disk (114) following the computer program product (115) Claim 8 contains. Powertrain control unit (110) adapted to be included in a motor vehicle (V) to accelerate the vehicle (V) from an initial speed (v ₀ ) to a target speed (v _t ) while a clutch (125 is progressively engaged) in the vehicle (V), wherein the drive train control unit (110) configured to: obtain a set of input parameters (v _0, v _t, m, F _e, L), and controlling the vehicle (V), so that it accelerates from the initial speed to the target speed based on the set of input parameters, characterized in that the control unit (110) comprises a processing circuit (112) configured to: determine a minimum acceleration (amine) required to achieve the desired speed (v _t ) with acceptable wear for the clutch (125), the minimum acceleration (a _min ) based on the set of Input parameters is determined, the driving resistance (F _e ) for the vehicle (V), a weight (m) of the vehicle (V), a maximum amount of energy (L) that can be absorbed by the clutch (125), and a speed difference ( Δv) between the initial and the target speed (v ₀ , v _t ) and generating a control signal (S _ctrl ) configured to control the vehicle (V) to be from the initial speed (v ₀ ) accelerated to the desired speed (v _t ) at least as quickly as specified by the minimum acceleration (a _min ). Powertrain control unit (110) after Claim 10 , wherein the processing circuit (112) is configured to determine the minimum acceleration (a _min ): in relation to the driving resistance (F _e ), and in a quadratic relationship with the speed difference (Δv). Powertrain control unit (110) after Claim 11 wherein the processing circuitry (112) is configured to determine the minimum acceleration (a _min ) as: $$\frac{{\text{F}}_{\text{e}}}{\frac{\text{2L}}{\Delta {\text{v}}^{\mathrm{2nd}}}-\text{m}},$$

where F _{e is} the driving resistance, L is the maximum amount of energy that can be absorbed by the clutch (125), Δv is the speed difference between the initial and the target speed, and m is the weight of the vehicle (V). Powertrain control unit (110) according to one of the Claims 10 to 12 , wherein the processing circuitry (112) is configured to either: treat the maximum amount of energy (L) that is absorbable by the clutch (125) as a constant number, or determine the maximum amount of energy (L) by the clutch (125 ) is absorbable, based on at least one of a current temperature of the clutch (125), a maintenance interval for the clutch (125) and a fuel consumption condition. Powertrain control unit (110) according to one of the Claims 10 to 13 , wherein the driving resistance (F _e ) comprises at least one of: a road gradient factor, an air resistance parameter and a rolling resistance parameter. Powertrain control unit (110) according to one of the Claims 10 to 14 , where the initial velocity (v ₀ ) is zero. Powertrain control unit (110) according to one of the Claims 10 to 15 , the desired speed (v _t ) being a highest speed at which the clutch (125) is fully engaged. Vehicle (V), comprising a drive train (120) and the drive train control unit (110) according to one of the Claims 10 to 15 to control the drive train (120).

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