METHOD AND DEVICE FOR ADJUSTING A SPECIFIC ANGLE POSITION OF A CRANKSHAFT OF A MOTOR VEHICLE DURING SERVICING OR ASSEMBLY WORK

Description

[0001] The invention relates to a method and a device for setting a specific angular position of a crankshaft of a motor vehicle during maintenance or assembly work.

[0002] It is known from experience that, during maintenance or assembly work, it may be necessary to adjust a specific angular position of a motor vehicle's crankshaft with the flywheel housing attached. Examples of such maintenance or assembly work include adjusting the valve clearance, precisely adjusting the injection timing based on the top dead center (TDC) position of a piston, or cylinder head assembly, which involves approaching the top dead center of the crankshaft.

[0003] Devices for manually cranking a reciprocating piston internal combustion engine and for setting a specific angular position of the crankshaft on the flywheel are known from the prior art. The use of such a manual cranking device 8 for an internal combustion engine is illustrated in Figures 4 and 5.

[0004] The barring device 8 can be secured in a viewing hole of a flywheel housing 6. In this position, a gear arrangement 9, in this case consisting of the three gears 9a, 9b, and 9c, engages with the starter ring gear 11, which is non-rotatably mounted on the flywheel 25, whereby the driven gear 9a can be rotated by means of a tool 12, e.g., a wrench. For this purpose, a tool engagement point 10, e.g., in the form of a polygon, is provided on the barring device 8. The Figures 4 and 5The fan-shaped representation of the tool 12 is intended only to show the various rotational positions of the tool 12.

[0005] The applied torque is transferred to the crankshaft, allowing a specific angular position, i.e., rotational position, of the crankshaft to be set. To do this, a mechanic can manually rotate the flywheel 25 using the barring device 8 until a mark on the flywheel 25, visible through the inspection hole, reaches a mark on the flywheel housing 6, e.g., in the form of a machined surface. The marks are set such that the rotational position or angular position of the flywheel corresponds to a predetermined rotational position or angular position of the crankshaft.

[0006] To set a specific angular position of the crankshaft using such a barring device 8, a certain amount of space must be kept free to allow access to the barring device 8. A further disadvantage is that setting a specific position of the crankshaft is cumbersome for the mechanic, as handling the barring device in a pit is difficult, especially during servicing. Furthermore, the barring process is time-consuming due to the low gear ratio of the barring device 8 to the starter ring gear 11. A particular disadvantage is that errors due to parallax can arise from manually reading the angular position via a machined surface on the flywheel housing 6 and the marking on the flywheel 25.

[0007] DE 100 49 193 A1 discloses a method for mobile testing of assemblies, particularly motor vehicle engines and transmissions. The assembly comprises a rotatably driven shaft that can be coupled to a starter generator. During testing or adjustment, the assembly is driven by the starter generator, while the testing and adjustment process is controlled by a testing and adjustment system integrated into the transport pallet. However, moving the crankshaft to a specific angular position using the crankshaft starter generator is not possible.

[0008] It is therefore an object of the invention to provide an improved method for adjusting a specific angular position of a motor vehicle crankshaft during maintenance or assembly work, which avoids the disadvantages of conventional techniques. The object of the invention is, in particular, to provide an improved method for adjusting a specific angular position of a motor vehicle crankshaft, which is characterized by a simplified and less error-prone process.

[0009] These objects are achieved by a device and a method according to the independent claims. Advantageous embodiments and applications of the invention are subject to the dependent claims and are explained in more detail in the following description, with partial reference to the figures.

[0010] According to general aspects of the invention, the above objects are achieved by a device for setting a specific angular position of a crankshaft of a motor vehicle during maintenance or assembly work, comprising a crankshaft starter generator and a control of the crankshaft starter generator, wherein the control is configured to control the crankshaft starter generator such that a rotor of the crankshaft starter generator assumes a rotational position which corresponds to at least one predetermined angular position of the crankshaft.

[0011] The invention is based on the fact that, in practice, drive train modules are increasingly being used that feature an electric machine that can be operated both as a motor and as a generator, in the form of an electric crankshaft starter generator (CSG), for example, arranged coaxially to the crankshaft and between the engine and transmission. In this case, the CSG is operatively connected to the crankshaft, for example, by the rotor of the CSG being rotationally fixedly connected to a flywheel arranged on the crankshaft when installed.

[0012] According to the invention, the angular position of the crankshaft is thus adjusted by means of the crankshaft starter generator, the control of which is programmed accordingly for this purpose. In addition to the previously common operating modes in which the KSG is used as a motor to start the internal combustion engine and / or to provide additional drive torque and / or as a generator to absorb and convert recuperation energy, the control is particularly configured to actuate the KSG in an operating mode for maintenance or assembly work, i.e. not during driving, to adjust at least one desired angular position of the crankshaft. An example of such a predetermined angular position of the crankshaft is top dead center (TDC).

[0013] This offers the advantage of eliminating the need for an additional manual barring device and the need for attaching corresponding visual markings to the flywheel and flywheel housing, resulting in cost savings. Moving to and setting a desired angular position of the crankshaft using a barring device is faster than positioning and manually operating previously known barring devices. Due to its inherent design, a barring device has a high angular accuracy of approximately 0.1° and no tolerance play, making adjustment using a barring device more precise and less prone to errors. Since the setting of the crankshaft angular positions is controlled electronically by the barring device control system, it is also possible to automatically document, in the event of a service call, that all relevant crankshaft positions have been moved to with a specified accuracy.

[0014] The crankshaft adjustment device can be used to adjust several specific angular positions of the crankshaft during maintenance or assembly work. For this purpose, several predetermined rotational positions of the rotor can be stored in the control system, each corresponding to one of several predetermined angular positions of the crankshaft. The control system can, for example, be configured to either adjust a specific one of these multiple rotational positions of the rotor or to adjust all of them one after the other.

[0015] According to the invention, the device further comprises a manually operated control element, preferably designed as a pushbutton or rotary knob, which is connected to the control unit via a signal line or wirelessly and with which the adjustment of the angular position of the crankshaft can be started and / or stopped by means of the control unit and the crankshaft starter generator. The manually operated control element is preferably used exclusively for adjusting the specific angular position of a motor vehicle's crankshaft during maintenance or assembly work and can be arranged in the driver's cab, on or near the drive train, or at another location on the vehicle that is advantageous for service or assembly work. This enables easy handling.

[0016] According to the invention, the control system is configured to generate a rotary movement of the rotor of the KSG when the control element is held down, as long as the manually operated control element is pressed, and to automatically move the rotor to a predetermined rotational position corresponding to the predetermined angular position of the crankshaft when the manually operated control element is pressed once. The control element is preferably designed as a button. This allows an operator to easily move the KSG to a specific rotational position themselves by holding down and subsequently releasing the control element, or to have it moved to this position automatically by briefly pressing it.

[0017] The controller can further be configured to move the rotor at a speed less than 10 rpm to adjust the predetermined angular position. Thus, in the operating mode according to the invention for adjusting an angular position of the crankshaft, the controller causes the rotor to rotate slowly compared to normal CSG operation, which rotation does not occur at an increasing speed, but preferably at a constant speed.

[0018] A further possible implementation according to the invention provides that the rotor can be rotated in both directions of rotation by the controller to set the predetermined angular position. The controller is preferably further configured to select the direction of rotation that requires the shortest rotational path of the rotor to set the predetermined angular position. This allows the average start-up time of the crankshaft to reach the predetermined angular position to be shortened.

[0019] As explained above, the control of the KSG is programmed to control the crankshaft starter generator in such a way that a rotor of the crankshaft starter generator assumes a rotational position that corresponds to at least one predetermined angular position of the crankshaft.

[0020] One possible way to configure the control system for setting the predetermined angular position is to continuously determine the current rotational position of the rotor relative to the stator of the crankshaft starter generator using a position sensor known per se from the prior art. For example, it is known in practice to detect the rotational position of the rotor relative to the stator, for example, using an additional cup-shaped or pot-shaped component that is non-rotatably attached to the flywheel. A special geometry or marking (sensor track) is applied to the component, which is picked up by an inductively or capacitively operating sensor of the position sensor to determine the position of the rotor.According to this variant, the controller can further be configured to determine, depending on the current rotational position of the rotor, a required rotation of the rotor, by means of which the rotor, starting from the current rotational position, reaches a predetermined rotational position of the rotor, which corresponds to the predetermined angular position of the crankshaft. The controller then outputs a control signal to the rotor so that it rotates until the calculated rotation is reached.

[0021] The invention further relates to a motor vehicle, preferably a commercial vehicle, having a device for setting a specific angular position of a crankshaft as disclosed herein.

[0022] According to general aspects of the invention, a method for setting a specific angular position of a crankshaft of a motor vehicle during maintenance or assembly work is further proposed, wherein the motor vehicle comprises a crankshaft starter generator whose rotor is connected in a rotationally fixed manner to a flywheel arranged on the crankshaft, wherein the method is characterized in that the angular position of the crankshaft is set by means of the crankshaft starter generator.

[0023] To avoid repetition, features disclosed purely in accordance with the device shall also be deemed to be disclosed in accordance with the method and shall be claimable. The aforementioned aspects and features according to the invention, in particular concerning the programming of the controller, also represent steps according to the method.

[0024] The above-described preferred embodiments and features of the invention can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings. They show: Figure 1 is a schematic block diagram illustrating an embodiment of the invention; Figure 2 is a cross-section of a drive train module with a crankshaft starter generator; Figure 3 is a schematic flow diagram of a method according to an embodiment of the invention; Figure 4 is a perspective view of a flywheel housing and a known barring device; and Figure 5 is a cross-sectional view of a flywheel housing and a known barring device.

[0025] Figure 1shows a schematic block diagram illustrating an embodiment of the invention. An electric crankshaft starter generator (CSG) 2 is provided between a transmission 6 and a flywheel device 5 of an internal combustion engine coaxially to the crankshaft 1. In Figure 1 The crankshaft is schematically represented by the dashed line, which represents the center axis of the crankshaft. The rotor of the crankshaft control unit 2 is rotationally fixed to the flywheel of the flywheel device 5, which in turn is rotationally fixed to the crankshaft 1. Such drive train arrangements are known per se from the prior art.

[0026] In Figure 2Only one possible variant of the structural design is shown by way of example, with only the components relevant to the invention being briefly explained below. The flywheel device 5 comprises a flywheel 25 and a flywheel housing 24 covering the flywheel 25 on the engine side. According to the Figure 2In the embodiment shown, the rotor 20 is fastened to the flywheel 25 exclusively by means of screws 23, so that the flywheel 25 and the rotor 20 are coupled in terms of movement. According to a further variant not shown, the rotor 20 can also be applied to a cylinder surface (fit fit) which is formed on the flywheel 25 and extends in the axial direction of the crankshaft 1. The KSG stator 21 is rigidly mounted on a KSG housing 22 and arranged concentrically to the rotor 20. The KSG housing 22 is screwed to the flywheel housing 24. On the output side, a gearbox 6 is fastened to the rotor 20 via flexible adapter plates, so-called flex plates. It is emphasized again that the structural design in Figure 2is merely exemplary and other structural designs of a drive train module with a KSG known from the prior art can also be used if the control of the KSG 2 is set up according to the invention to use the KSG 2 to set a specific angular position of a crankshaft 1 of a motor vehicle within the scope of maintenance or assembly work.

[0027] As in Figure 1 As shown, the operation of the KSG 2 is controlled by a control unit 3, which controls the KSG 2, for example, in a manner known per se in order to carry out a starting process of the internal combustion engine.

[0028] According to the present invention, the functionality of the control unit 3 is expanded such that it can control the crankshaft timing gear not only during driving, but also for setting a specific angular position of the motor vehicle's crankshaft 1 during maintenance or assembly work. For this purpose, a manually operated control element 4 is also provided on the vehicle, in this case designed as a button, which is connected to the control unit 3 via a signal line 7.

[0029] As shown in the flow chart of the Figure 3 As shown, the control unit 3 is configured to detect an actuation signal of the control element 4 (step S1) and, depending on the detected actuation signal, to control the KSG in order to rotate the rotor 20 until the angular position of the crankshaft 1 desired by the user is set (step S2).

[0030] If a user presses and holds button 4 during maintenance or assembly work, the control unit 3 is programmed to respond to the actuation signal received via line 7 by energizing rotor 20 so that it rotates smoothly and slowly. The speed is below 10 rpm. As a result, the crankshaft also rotates at the same speed. If the user releases button 4, the control unit 3 interrupts the power supply to rotor 20, causing rotor 20 to stop. In this operating mode, the user can initiate a general crankshaft rotation or manually move the crankshaft to any desired angular position.

[0031] If, on the other hand, the control unit 3 detects from the received actuation signal that the button was only pressed once briefly and then released again, the control unit 3 controls the KSG 2 such that the rotor 20 automatically moves into a predetermined rotational position relative to the stator 21. The predetermined rotational position of the rotor corresponds to a predetermined rotational position, i.e. angular position, of the crankshaft 1. The predetermined rotational position of the rotor 20 is stored in a memory of the control unit 3. By means of an inductively or capacitively operating and known position sensor (not shown), the current rotational position of the rotor 20 relative to the stator 21 of the KSG 2 was previously determined. It is known from practice, for example, to enable the detection of the rotational position from rotor to stator by means of an additional cup-shaped or pot-shaped component (not shown) which is attached to the flywheel in a rotationally fixed manner.A special geometry or marking (sensor track) is applied to the component, which is picked up by an inductive or capacitive sensor of the position sensor to determine the rotational position of the sensor track and thus of the rotor 20. The control unit 3 calculates the required rotation of the rotor 20 to assume the predetermined rotational position by forming the difference between the predetermined rotational position and the current rotational position. The control unit then outputs a corresponding control signal corresponding to the calculated rotational position to the KSG 2 so that the KSG rotor 20 rotates until the required rotational position and thus the angular position of the crankshaft is reached. List of reference symbols

[0032] 1 Crankshaft 2 Crankshaft starter generator (KSG) 3 KSG control unit 4 Actuating element, e.g. button 5 Flywheel device 6 Gearbox 7 Signal line 8 Barring device 9 Gear arrangement 9a, 9b, 9c Gear 10 Tool application point 11 Starter ring gear 12 Tool 20 KSG rotor 21 KSG stator 22 KSG housing 23 Screw 24 Flywheel housing 25 Flywheel

Claims

1. Device for setting a specific angular position of a crankshaft (1) of a motor vehicle in the context of maintenance or assembly work, characterised by a crankshaft starter generator (2) and a controller (3) of the crankshaft starter generator (2), wherein the controller (3) is set up to control the crankshaft starter generator (2) in such a way that a rotor (20) of the crankshaft starter generator (2) assumes a rotational position which corresponds to a predetermined angular position of the crankshaft (1); a) wherein the device has a manually operated control element (4) which is connected to the controller (3) via a signalling line (7) or wirelessly and with which the setting of the angular position of the crankshaft (1) can be started and / or stopped by means of the controller (3) and the crankshaft starter generator (2); wherein the controller is arranged to generate a rotary movement of the rotor (20) of the crankshaft starter generator (2) when the control element (4) is held depressed as long as the manually actuated control element (4) is depressed, and to automatically move the rotor (20) into a predetermined rotational position which corresponds to the predetermined angular position of the crankshaft (1) when the manually actuated control element (4) is briefly depressed once.

2. Device according to claim 1, characterised in that the predetermined angular position of the crankshaft (1) corresponds to a top dead centre.

3. Device according to one of the preceding claims, characterised in that a plurality of predetermined rotational positions of the rotor (20) are stored in the controller (3), each of which corresponds to one of a plurality of predetermined angular positions of the crankshaft (1).

4. Device according to one of the preceding claims, characterised in that the manually operated control element (4) is designed as a button.

5. Device according to one of the preceding claims, characterised in that the control (3) is set up to move the rotor (20) for setting the predetermined angular position at a speed which is less than 10 rpm.

6. Device according to one of the preceding claims, characterised in that the rotor (20) can be rotated in both directions of rotation by the controller (3) in order to set the predetermined angular position, the controller (3) being set up to select the direction of rotation which requires the shortest rotational path of the rotor (20) in order to set the predetermined angular position.

7. Device according to one of the preceding claims, characterised in that the controller (3) for setting the predetermined angular position is set up to determine a current rotational position of the rotor (20) relative to the stator (21) of the crankshaft starter generator (2) and to determine a required rotation of the rotor (20) as a function of the current rotational position of the rotor (20), by means of which the rotor (20), starting from the current rotational position, reaches a predetermined rotational position of the rotor (20), which corresponds to the predetermined angular position of the crankshaft.

8. Motor vehicle, preferably a commercial vehicle, with a device according to one of the preceding claims.