Method for starting an internal combustion engine for a motor vehicle, and drive train for a motor vehicle

Abstract

A method is provided for starting an internal combustion engine with a driveshaft for a motor vehicle. A starting process is carried out, by which the internal combustion engine is started and thereby transferred from a deactivated state into a powered operation, wherein the starting process is carried out by a pinion starter and by a belt starter, by which the driveshaft is driven during the starting process.

Claims

1. A method for starting an internal combustion engine, having a driveshaft, for a motor vehicle, comprising: performing a starting process by which the internal combustion engine is started so as to transfer from a deactivated state into powered operation, wherein the starting process is performed by a pinion starter and by a belt starter, by which the driveshaft is driven during the starting process, and the driveshaft is, during the starting process, driven at least temporarily simultaneously by the pinion starter and by the belt starter.

2. The method according to claim 1, wherein the starting process comprises: a first time interval, during which the driveshaft is driven by the pinion starter and the belt starter does not drive the driveshaft; and a second time interval, during which the driveshaft is driven by the belt starter and the pinion starter does not drive the driveshaft.

3. The method according to claim 2, wherein the second time interval at least partially overlaps the first time interval.

4. The method according to claim 1, wherein the pinion starter is operated with an electrical voltage of twelve volts.

5. The method according to claim 4, wherein the belt starter is operated with an electrical voltage of twelve volts.

6. The method according to claim 4, wherein the belt starter is operated with an electrical voltage of more than 20 volts.

7. The method according to claim 4, wherein the belt starter is operated with an electrical voltage of more than 40 volts.

8. A drivetrain for a motor vehicle having an internal combustion engine with a driveshaft and by which the motor vehicle is driven, comprising: a starting device, by which a starting process is performed in order to start the internal combustion engine so as to transfer the internal combustion engine from a deactivated state into powered operation, wherein the starting device has a pinion starter and a belt starter by which, in order to perform the starting process, the driveshaft is drivable during said starting process, and the driveshaft is, during the starting process, driven at least temporarily simultaneously by the pinion starter and by the belt starter.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The single FIGURE is a schematic illustration of a drivetrain for a motor vehicle, wherein the drivetrain is designed for carrying out a method for starting an internal combustion engine of the drivetrain.

DETAILED DESCRIPTION OF THE DRAWING

(2) The single FIGURE shows, in a schematic illustration, a drivetrain 1 for a motor vehicle, in particular for a motor car such as for example a passenger automobile. The drivetrain 1 has an internal combustion engine 2 which is designed for example as a reciprocating-piston engine and which comprises a plurality of combustion chambers 3. A respective combustion chamber 3 is designed for example as a cylinder. The internal combustion engine 2 is also referred to as an engine or a combustion engine and furthermore has a driveshaft 4, which is for example in the form of a crankshaft. A respective piston is received, so as to be movable in translational fashion, in the respective combustion chamber 3. The respective piston is articulatedly coupled to the driveshaft, such that translational movements of the respective piston in the respective combustion chamber 3 are converted into a rotational movement of the driveshaft 4.

(3) During powered (fired) operation of the internal combustion engine 2, combustion processes take place in the combustion chambers 3 and thus in the internal combustion engine 2, by means of which combustion processes the pistons and, via these, the driveshaft 4 are driven. In a deactivated state of the internal combustion engine 2, no combustion processes take place in the internal combustion engine or in the combustion chambers 3, such that the pistons and thus the driveshaft 4 are at a standstill.

(4) The drivetrain 1 furthermore comprises at least one axle 5 with wheels 6, wherein the wheels 6 and thus the motor vehicle as a whole can be driven by the internal combustion engine 2. In particular during the powered operation thereof, the internal combustion engine 2 is operated for example in traction operation, in which the wheels 6 can be driven or are driven by the driveshaft 4, and thus by the internal combustion engine 2, in particular via a differential transmission 7, a shaft 8 and a clutch 9.

(5) The drivetrain 1 furthermore comprises a starting device which is denoted as a whole by 10 and by means of which a starting process can be performed in order to start the internal combustion engine 2 by way of the starting process and thereby transfer the internal combustion engine from the deactivated state into powered operation. In other words, a method for starting the internal combustion engine 2 is performed by means of the starting device 10. In the method, the above-stated starting process is performed, by which the internal combustion engine 2 is started and thereby transferred from the deactivated state into powered operation.

(6) In order to now be able to perform the starting process with a particularly low level of vibration and thus in a comfortable manner, and at the same time keep the structural space requirement, the weight and the costs of the starting device 10 particularly low, the starting device 10 comprises a pinion starter 11, which is also referred to as a cold starter, and a belt starter 12, which is also referred to as a traction mechanism starter and by which the driveshaft 4 can be driven during the starting process in order to perform the starting process. In other words, in the course of the method, provision is made whereby the starting process is performed by the pinion starter 11 and by the belt starter 12, by which the driveshaft 4 is driven during the starting process. The pinion starter 11 is a first starter or is also referred to as the first starter of the starting device 10, whereas the belt starter 12 is a second starter or is referred to as the second starter of the starting device 10.

(7) The pinion starter 11 has a first electric machine 13 which is operable as an electric motor, a first toothed gear in the form of a pinion 14, and a second toothed gear in the form of a toothed ring 15, by means of which it is for example possible for the driveshaft 4 to be driven. Here, the toothed ring 15 is for example at least indirectly connected rotationally conjointly to the driveshaft 4. It can be seen from the FIGURE that the pinion 14 can be driven by the electric machine 13, wherein the toothed ring 15 can be driven by the pinion 14 and thus, via the pinion 14, by the electric machine 13. In this way, the driveshaft 4 can be driven by the electric machine 13 via the toothed ring 15 and the pinion 14. Thus, during the starting process, the driveshaft 4 is driven by the electric machine 13 via the toothed ring 15 and the pinion 14.

(8) The belt starter 12 has a traction mechanism drive 20, which has a first drive wheel 16, a traction mechanism 17 designed for example as a belt, and a second drive wheel 18. Here, the driveshaft 4 can be driven for example by the second drive wheel 18 because, for example, the second drive wheel 18 is connected rotationally conjointly to the driveshaft 4. The drive wheel 18 and in particular the traction mechanism 17 can be driven by the drive wheel 16 because, for example, the traction mechanism 17 at least partially loops around each of the drive wheels 16 and 18. The drive wheel 16 can in turn be driven by a second electric machine 19 of the belt starter 12, which comprises the second electric machine 19. The second electric machine 19 can be operated as an electric motor, by means of which the drive wheel 16 can be driven or is driven. During the starting process, the driveshaft 4 is thus driven by the electric machine 19 via the drive wheel 18, the traction mechanism 17 and the drive wheel 16.

(9) In particular, the starting process has a first time interval and a second time interval which at least partially follows the first time interval. During the first time interval, the driveshaft 4 is for example driven by means of the pinion starter 11, whilst drive of the driveshaft 4 effected by means of the belt starter 12 is not provided. During the second time interval, the driveshaft 4 is for example driven by the belt starter 12, whilst drive of the driveshaft 4 effected by means of the pinion starter 11 is not provided. The first time interval is for example a first phase, whereas the second time interval is a second phase. Between the first phase and the second phase there is for example situated a transition phase, via which the first time interval or the first phase transitions into the second time interval or the second phase respectively. During the transition phase, it is for example the case that the driveshaft 4 is driven by the pinion starter 11 and by the belt starter 12 simultaneously, such that, during the transition phase, it is for example the case that the pinion starter 11 and the belt starter 12 simultaneously drive the driveshaft 4.

(10) It is for example the case that a breakaway torque of the driveshaft 4 is overcome by means of the first phase and thus by means of the pinion starter 11. After the first phase, it is for example the case that the belt starter 12 is activated in addition to the pinion starter 11, such that both the pinion starter 11 and the belt starter 12 are operated simultaneously during the transition phase. Following this, the belt starter 12 takes over a cranking process, in the course of which the driveshaft 4 is cranked by way of the belt starter 12 and thus brought to a predefinable rotational speed. For this purpose, it is for example the case that, after the transition phase, the pinion starter 11 is deactivated, such that, during the second phase, the driveshaft 4 is driven only by the belt starter 12, but not by the pinion starter 11. The second phase lasts in particular until such time as combustion processes take place in the combustion chambers 3, by which combustion processes the driveshaft 4 is driven. The second phase is then ended by virtue, for example, of the belt starter 12 being deactivated.

(11) The starting process is also referred to as cooperative starting, because the starters assist or supplement one another. By virtue of the fact that only the breakaway torque is overcome by way of the pinion starter 11 and the actual cranking process is performed by way of the belt starter 12, the internal combustion engine 2 can be started with a particularly low level of vibration and thus in a particularly comfortable manner. The starting process is in particular a so-called cold start, which is performed not automatically, for example, by an electronic processing device of the drivetrain 1, but rather as a result of an actuation by the driver of the motor vehicle of an operator control element which is arranged for example in the interior compartment of the motor vehicle.

LIST OF REFERENCE DESIGNATIONS

(12) 1 Drivetrain 2 Internal combustion engine 3 Combustion chambers 4 Drive shaft 5 Axle 6 Wheel 7 Differential transmission 8 Shaft 9 Clutch 10 Starting device 11 Pinion starter 12 Belt starter 13 First electric machine 14 Pinion 15 Toothed ring 16 First drive gear 17 Traction mechanism 18 Second drive gear 19 Second electric machine 20 Traction mechanism drive

(13) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.