GB2582036A

GB2582036A - Method for controlling a starting procedure

Info

Publication number: GB2582036A
Application number: GB1912160.7A
Authority: GB
Inventors: Frauenkron Helge
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-08-27
Filing date: 2019-08-23
Publication date: 2020-09-09
Anticipated expiration: 2039-08-23
Also published as: DE102018214425A1; GB2582036B; GB201912160D0

Abstract

A method for controlling a starting procedure of a motor vehicle in which a length of a first starting phase (41) is specified therein by a driver; the motor vehicle is operated in the first starting phase (41) in such a way that its driven wheel or its driven wheels spin; and in a second starting phase (42), a desired wheel slip (DWS) is regulated to a value which permits maximum acceleration of the motor vehicle. The DWS in the first starting phase may be regulated to an applicable value; in the first starting phase the DWS may be regulated to a value of more than 2.0 and in the second starting phase it may be regulated to a value in the range of 1.0 to 1.2; and the regulation of the DWS may be performed by a traction control system.

Description

Method or contra ffuL a sta vocedure The present invention relates to a method for controlling a starting procedure of a motor vehicle. Furthermore, the present invention relates to a computer program which performs each step of the method, and to a machine-readable storage medium which stores the computer program. Finally, the invention relates to an electronic control device which is arranged to carry out the method.

Prior Art

Many motor vehicles comprise an assist system which helps the driver to accelerate out of a standing start as quickly as possible. It is referred to as launch control. For this purpose, the dutch and gearbox are controlled in such a way that, during starting, the engine speed is such that the motor vehicle accelerates in an ideal manner from a standing start with an optimal degree of slipping. According to the programming, the transmission of the motor vehicle or its quickshifter shifts to the next gear only at optimal engine speed, until the design-imposed maximum speed or another parameter is reached. Optimal wheel slip is regulated by a traction control system (TCS), also referred to as automatic slip control or traction control, in order to prevent wheelspin on the motor vehicle.

Some sports cars additionally have an operating mode in which the starting assist system is applied not to the maximum acceleration but to the most dramatic starting procedure with wheelspin. This is also referred to as a racing start. In the racing start the wheels leave black marks behind on the road. In the racing start, the traction control system is switched off so that it does not intervene and prevent wheel spin.

DE 10 2015 214 937 Al describes a method for actuating an electronic clutch -1 - -2 -system of a vehicle during a starting procedure, in which, in a slip starting operating mode, a clutch is engaged by the electronic clutch system only so far that a specifiable wheel slip occurs. This permits a racing start with wheelspin.

Disclosure of the invention

In the method for controlling a starting procedure of a motor vehicle, a length of a first starting phase is first specified by a driver. Then the motor vehicle is operated in the first starting phase in such a way that its driven wheel (if the motor vehicle has two wheels) or its driven wheels spin. In a second starting phase which follows the first starting phase, a desired wheel slip of the motor vehicle is regulated to a value which permits maximum acceleration of the motor vehicle.

While the driver of a motor vehicle which has a starting procedure controlled in a conventional manner at best has the selection of allowing the motor vehicle to start either with optimal acceleration or in the most dramatic way possible, the present method allows these two functionalities to be combined. In the first starting phase, a racing start is performed and the motor vehicle then passes into the second starting phase which is optimised for maximum acceleration.

Termination of the second starting phase can take place in particular in the manner known in the prior art for launch control when the design-imposed maximum speed of the motor vehicle is reached or another parameter is reached.

It is preferred that the desired wheel slip is not only regulated in the second starting phase but that it is also regulated to an applicable value in the first starting phase In this way it is possible to ensure that a high degree of wheel slip is retained in the racing start.

For this purpose, in the first starting phase, the desired wheel slip is preferably regulated to a value of more than 2.0, particularly preferably to a value of more than 3.0, most preferably to a value of more than 3.5. In the second starting phase, it is regulated preferably to a value in the range of 1.0 to 1.2, particularly preferably to a value in the range of 1.0 to 1.1 in order to achieve maximum acceleration. Thus, for a motor vehicle with driven wheels and with non-driven wheels the wheel slip of a driven wheel is defined as the wheel speed of the -3 -specific driven wheel divided by the averaged wheel speed of the non-driven wheels. For a motor vehicle with all-wheel drive the wheel slip of a driven wheel is defined as the wheel speed of the specific driven wheel divided by the speed of the motor vehicle over the ground.

The regulating of the desired wheel slip can be performed in particular by a traction control system. With respect to the desired wheel slip in the second starting phase, the known launch control procedure can be followed. In the present method, however, provision can also be made that the traction control system is arranged such that it can also regulate the desired wheel slip of the first starting phase, wherein the spinning of the driven wheel or of the driven wheels in this starting phase is tolerated.

The change in the desired wheel slip during the transition from the first starting phase to the second starting phase can in particular be performed in a ramped or filtered manner in order to permit a transition between the two starting phases which is comfortable for the driver. Alternatively, however, a sudden change in the desired wheel slip can also be provided in order to change as quickly as possible from the first starting phase to the second starting phase.

The specifying of the length of the first starting phase by the driver is performed in one embodiment of the method by a setting unit which is disposed in the motor vehicle and is connected to an electronic control device of the motor vehicle. In another embodiment of the method, the specifying is performed by means of a mobile device, in particular by means of a smart phone which communicates with the electronic control device wirelessly.

In different embodiments of the method, the length of the first starting phase can be specified by the driver in a different way: In one embodiment, the length of the first starting phase is specified over the distance to be travelled in the first starting phase This distance to be travelled then also corresponds to the length of the black marks which are left on the road in the racing start In this embodiment, the distance actually travelled in the first starting phase, which as a condition for the termination of the first starting phase -4 -is compared with the distance to be travelled, can be determined in particular by integration of a speed of its non-driven wheel or of its non-driven wheels. When the motor vehicle is a motor vehicle with all-wheel drive which does not have non-driven wheels provision can in particular alternatively also be made that the travelled distance is determined from a longitudinal acceleration of the motor vehicle or by means of a GPS system.

In another embodiment of the method, the length of the first starting phase is specified not over the distance to be travelled in the first starting phase but rather over the time duration thereof The computer program is arranged to carry out each step of the method in particular when run on a computing device or an electronic control device. It permits the implementation of different embodiments of the method on an electronic control device without having to make structural changes thereon. For this purpose it is stored on the machine-readable storage medium.

By running the computer program on a conventional electronic control device the electronic control device is obtained and is arranged to control a starting procedure of the motor vehicle by means of the method.

Brief description of the drawings

By way of example only, specific embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 schematically shows components of a motor vehicle, the starting procedure of which can be controlled by means of a method according to an exemplified embodiment of the invention.

Figure 2 shows a flow diagram of an exemplified embodiment of the method in accordance with the invention Figure 3 shows a graph of the time progression of a desired wheel slip and the time progression of a distance travelled by a motor vehicle in one exemplified -5 -embodiment of the method in accordance with the invention Exemplified embodiments of the invention A motor vehicle 10 illustrated in figure 1 has an internal combustion engine 1L This is connected via a clutch 12 and a transmission 13 to a driven axle 14. The driven wheels 15, 16 of the motor vehicle 10 are disposed on the driven axle 14. In this case in the present exemplified embodiment these are the rear wheels of the motor vehicle 10. Its front wheels function as non-driven wheels 17, 18. An electronic control device 20 controls the internal combustion engine 11, the clutch 12 and the transmission 13. It has a traction control system 21. A setting unit 22 in the cabin of the motor vehicle 10 is likewise connected to the electronic control device 20.

In one exemplified embodiment of the method in accordance with the invention, which is schematically illustrated in figure 2, after the internal combustion engine 11 is started 30, the driver of the motor vehicle 10 uses the setting unit 22 to set 31 a length of a distance which the motor vehicle 10 is to travel when starting in a racing start mode before it changes into a maximum acceleration mode. Then, by means of the traction control system 21, a desired wheel slip DWS is up-regulated 32 from an initial value of 1.0 at a time B to a value of 3.8. The change in the desired wheel slip DWS is illustrated with the time t in figure 3. In a first starting phase 41 which now follows, the motor vehicle 10 is operated with the high desired wheel slip DWS so that its driven wheels 15 and 16 spin. A racing start is thus performed. By integrating the speed of the non-driven wheels 17, 18 of the motor vehicle 10, the distance s travelled by the motor vehicle 10 is determined. When a check 33 shows that the distance s at the time t2 has reached the length si specified by the driver, the desired wheel slip DWS ramped to a value of 1.1 is down-regulated 34. This down-regulating and the subsequent regulating of the desired wheel slip DWS are performed by means of the traction control system 21. In so doing, the clutch 12 is always closed only far enough that the actual wheel slip corresponds to the desired wheel slip DWS.

The further operation of the motor vehicle 10 is performed in a second starting 35 phase 42. In this phase, the regulating of the desired wheel slip DWS to the value -6 -of 1.1 which is optimal in the present exemplified embodiment for the maximum acceleration of the motor vehicle 10 is performed. From a time t3 the motor vehicle 10 thus undergoes maximum acceleration. Only when a check 35 shows that the motor vehicle 10 has reached its design-imposed maximum speed does a termination 36 of the method take place and the travel behaviour of the motor vehicle 10 then follows its usual operating regime Up to this point, the electronic control device 20 in the second starting phase 42 follows programming according to which the transmission 13 is always switched into the next highest gear only at optimal engine speed.

In a second exemplified embodiment of the invention, not illustrated, the motor vehicle 10 has all-wheel drive. In this exemplified embodiment, the distance s travelled is not determined by integration of wheels speeds but instead the determination is performed from a longitudinal acceleration of the motor vehicle 10. This is measured by means of an acceleration sensor, not illustrated.

In a second exemplified embodiment of the invention, not illustrated, the motor vehicle 10 likewise has all-wheel drive. In this exemplified embodiment, the distance s travelled is determined by means of a GPS system In a fourth exemplified embodiment of the method, the length of the first starting phase 41 is not set by the driver over the length Si of the distance s travelled. Instead, the setting unit 22 is arranged to set a time duration of the first starting phase 21. When the check 33 shows that the difference between the time t2 and the time ti corresponds to the time duration set by means of the setting unit 22, the method is continued with the regulating 34 of the desired wheel slip DWS to the value for the second starting phase 42.