CH713815A1 - Method for adjusting the valve clearance of an internal combustion engine. - Google Patents

Abstract

The present invention relates to a method for automatically adjusting the position of the angular position of the crankshaft and, via the camshaft drive, the camshaft of an internal combustion engine for adjusting the valve clearance. In this case, the crankshaft and thus the camshaft is rotated by a drag torque in a defined angular position by means of an electronic control system (10) to adjust the valve clearance of one or more valves. The drag torque is preferably applied to the crankshaft with the starter / starter motor.

Description

Description [0001] The invention relates to a method for positioning the crankshaft and / or camshaft of an internal combustion engine for adjusting the valve clearance.

In an internal combustion engine in reciprocating design, the opening widths of the intake and exhaust ports of a cylinder primarily in dependence of the piston position, in four-stroke engines with additional consideration of the present clock - and secondarily by the engine operating strategy, from which the desired valve lift curve due to the concrete Design of the cam contours yields-specified, ie be opened or closed continuously. The respective opening width of a valve or valve set is specified via the roller plunger, the component of the valve drive which picks up the cam contour.

Within a certain angular range of the rotating camshaft, a valve channel or a valve channel pair remains closed. In this case, the force exerted by a spring element force to close the valve channel. Within a complementary angular range of the camshaft, one of the force exerted by this spring element counteracts via the valve drive, which leads to an opening and subsequently closing valve channel.

Starting from a switched off and thus cooled up to an internal combustion engine at operating temperature takes place at the valve in terms of its function, a relevant thermal expansion. So that the so-called control times (the onset of the valve opening movement and the completion of the closing movement) of the internal combustion engine have as little temperature dependence as possible, a certain valve clearance is provided along the valve drive. This is sensibly quantified by a specific gap determined for the internal combustion engine cooled to the ambient temperature.

The ignition angle is in the example shown at 0 °, the curve 1 describes the course of the opening width of the exhaust valve of the cylinder under consideration, the Curve 2 that of the associated inlet valve. Excessive valve clearance leads to increased valve wear (and a loud valve rattle). Due to the nature of a cam contour, the movement of the valve train at the beginning of the phase of the valve train movement, which leads to an opening of the passage channel, is comparatively slow. If the traction between the valve train and the valve at a larger phase angle, then the valvetrain before each opening process at a much higher speed on the valve style. In addition, too high a valve clearance causes a shortening of the opening periods. If the combustion chamber does not receive enough fresh air, or too little oxygen, and / or the exhaust gas can not escape from the combustion chamber in the required amount, this can lead to increased fuel consumption and increased soot emissions.

Too little valve clearance leads to a longer opening period of the valve channel and in the extreme case that this is no longer completely closed. Even an excessively large period of an open exhaust valve causes a loss of performance, because during the expansion phase, a part of the combustion gases escapes at the prematurely opened exhaust valve instead of delivering its expansion power to the piston. Furthermore, there is an increased thermal wear of the valve disk and the valve seat rings, because reduces the discharged over the cylinder head portion of the waste heat. Instead of a sufficient residence time and thus sufficient heat dissipation through the cylinder head and the liner, the exhaust gas escapes through the outlet at a higher temperature and thus heats the exhaust valve and its valve seat ring more. In addition, there is a longer period before the valve plate of the exhaust valve is seated again on the cylinder head and thus uses a heat dissipation.

As can be seen from the preceding text, the exact setting of the valve clearance is of great importance, which relates to the cold to lukewarm internal combustion engine, depending on the engine type in the order of a few hundredths to a few tenths of a millimeter lies. For a purposeful adjustment of a valve clearance can take place, the camshaft must, of course, be in such an angular position at which the gap present in the valve train reaches its maximum.

Unlike modern cars, the diesel engines used in on-road and off-road commercial vehicles as well as in maritime applications are not equipped with an automatic valve clearance compensation due to other conditions. This also applies to gas engines. If the latter had an automatic valve clearance compensation, they would be subject to a high risk of damage due to irreversible flashbacks.

For this reason, a control of the present valve clearance and possibly necessary readjustment of the valve clearance in the course of engine / vehicle / engine maintenance useful.

For the adjustment of the valve clearance, the service technician / fitter currently has to operate the crankshaft manually in order to achieve the corresponding valve position for adjusting the valve clearance. The manual operation of the crankshaft is repeated until all valves of the individual cylinders of the internal combustion engine could be readjusted. For manual operation of the crankshaft, a special hand tool is usually used, which is attached to the flywheel or mounted on this. The previous approach, however, especially in mobile machines to problems, because of the high diversity of different engine installation situations, the location of this hand tool on the engine and the position at which the tool must be operated by hand, often difficult to access. In addition, the internal combustion engines are usually connected with their main outputs without coupling. Consequently, to adjust the crankshaft angular position, the entire load of the drive unit must be rotated.

Starting from this problem will be sought after a novel method that allows a simplified adjustment of the valve clearance in an internal combustion engine, especially for mobile machines.

This object is achieved by the method according to the features of claim 1. Advantageous embodiments of the method are the subject of subsequent to the main claim dependent claims.

According to the invention, a method for automatically positioning the angular position of the crankshaft and / or camshaft of an internal combustion engine for adjusting the valve clearance is proposed. By means of a control system, a drag torque is to be generated for the internal combustion engine, thereby automatically positioning the crankshaft in a defined angular position in which the valve clearance of a valve or a valve pair or more valves or more pairs of valves of the engine is verifiable and appropriately adjusted.

The control system makes a manual operation of the crankshaft for the adjustment of the valve clearance superfluous and ensures that a corresponding drag torque is applied to the crankshaft for a certain period of time to this or the indirectly driven over camshaft targeted and automated into a desired Angular position for adjusting the valve clearance to spend one or more valves. That the crankshaft / camshaft is positioned by machine so that the existing gap in the valve train for one or more valves reaches its maximum.

The control system can basically generate even the necessary drag torque by an integrated drive and apply to the engine. It makes more sense, however, if the control system of external components of the internal combustion engine or of the motor vehicle, ideally already existing and necessary for the regular engine operation components, used for the generation of the drag torque. A suitable component is the starter of the internal combustion engine. The starter can be actuated by the control system. Preferably, the time and / or duration of the starter operation are controlled by the control system to spend by means of the starter and the drag torque generated by this, the crankshaft in the desired actual angular position for the adjustment of the valve clearance.

In a preferred embodiment, the control system is composed of at least one engine control unit of the motor vehicle and / or at least one separate operating device. The engine control unit corresponds to the usual engine control unit for the regular operation of the internal combustion engine or the driven vehicle in the ferry.

Preferably, the engine control unit and operating device form a distributed control system, the basic process steps, i. the control functions and control algorithms are preferably implemented as software functions within the engine control unit, while the separate operating device merely forms a visual input and output interface to the engine control unit. However, it is also conceivable to distribute the software functions on both devices or outsource completely to the HMI device.

The separate control unit can be firmly integrated into the vehicle, but is preferably a version of an external, in particular portable control unit, which is connectable via a communication interface with the engine control unit of the engine. Conceivable here is the use of a laptop, tablets, smartphones or other portable device with appropriate software. The use of a stationary computer is of course also possible. Operator commands can be transmitted to the engine control unit via the bidirectional communication interface and engine or process parameters can be transmitted from the engine control unit to the operating unit for visualization in the opposite direction.

It may be useful to temporarily deactivate one or more motor functions not required for the execution of the method during execution of the method. Consequently, the regular operation of the internal combustion engine can be switched to a service operation of the internal combustion engine. For example, the deactivation of the ignition key function / mechanism or an electrical system connected thereto and / or the deactivation of an electric engine start button and / or any automatic start / stop function are helpful and useful. Further, it is useful to control fuel injection during process execution, i. when turning the crankshaft, disable it to prevent accidental ignition of the engine. In externally ignited internal combustion engines, an additional deactivation of the spark ignition makes sense.

For the accurate adjustment of the desired target crankshaft position, a sensory detection of the actual angular position of the crankshaft is desirable, in particular, the actual angular position should ideally by a sensor installed on the crankshaft and / or the flywheel and / or the camshaft sensor directly or alternatively be detected indirectly. In the case of indirect detection, the actual angular position is calculated, for example, from one or more other measured variables.

In principle, the detection of the direction of rotation or detection of a reversal of the direction of rotation of the crankshaft and / or camshaft and / or the flywheel is sufficient. At best, an immediate detection of the absolute angular position of the crankshaft and / or camshaft is provided. The crankshaft position can be detected, for example, by means of one or more detectable elements mounted on the flywheel, in particular on the lateral surface of the flywheel.

In four-stroke engines, two full revolutions of the crankshaft are necessary for passing through all four cycles. Since the camshaft, unlike the crankshaft, passes through only one revolution during a working cycle of a cylinder, it can be determined by separate detection of the camshaft position, whether the crankshaft is in the first or second revolution. In a widespread method for detecting the crankshaft angle position, for example, next to a camshaft sensor - to detect whether the crankshaft is in the angular range of 0 ° to 360 ° or above it to 720 ° - on the lateral surface of the flywheel of a correspondingly positioned sensor detectable elements attached, for example, a - apart from a detection of a reference angular position - uniform arrangement of metal teeth, which can be detected by distance sensor. To enable a high-resolution crankshaft angle position determination, for example, the application of an analog measurement principle offers, if this analog value or a derived digital value of a certain number of bits is available in the engine control unit. As one of many possible measurement principles, a sensor based on the Hall effect can also be used. From the detection of reference positions of the crankshaft angle position and the summation of the taking into account the present directions of rotation of the respective covered angle amounts, the instantaneous crankshaft angle position can be calculated. A detection of the crankshaft rotation direction can be achieved, for example, by using at least two sensors.

Taking into account the detected actual angular position of the crankshaft and in dependence of one or more firing angle of the internal combustion engine, the deactivation point for deactivating the starter or deactivating the drag torque can then be determined.

For the necessary determination of the time for deactivation of the drag torque, it is of interest to which outlet angle the crankshaft turns off after the removal of the defined drag torque. For this reason, it is preferably determined at the start of the process by which outlet rotation angle the crankshaft continues to rotate after deactivation of an applied drag torque, in particular after the starter has been switched off. For this purpose, the actual angular position of the crankshaft at the time of removal of the applied drag torque is compared with the assumed actual angular position after the complete coasting and standstill of the crankshaft. Alternatively, of course, a corresponding reference value of the outlet rotation angle already in the control system, in particular in the operating device and / or engine control unit, be deposited or be retrievable from an external database.

The actual outlet rotation angle depends not only on the type of internal combustion engine and the prevailing environmental conditions (oil temperature, coolant temperature, engine temperature, etc.), but also on which loads must be dragged along the drive train. Due to the large number of unknowns, it therefore makes sense to determine the outlet rotation angle by a measurement run under real conditions. For the process execution, it is assumed that the ambient conditions remain virtually constant during the process duration or that the outlet rotation angle remains approximately constant. There is nothing wrong with repeating the measuring procedure one or more times during the course of the procedure.

For optimum reproducibility of the outlet rotation angle, it may be useful if the starter is driven for each setting of the crankshaft angular position for a minimum period, since usually only after a short time of about one to max. set a periodic speed curve or a periodic course of the output from the starter to the internal combustion engine periodic drag power five seconds. The achievement of a periodic speed-time profile can be determined based on the crankshaft speed and / or the supply voltage of the starter or the starter current. It is therefore conceivable to equip the energy source of the starter, in particular the starter battery, with a suitable sensor or to use an already existing sensor for the optional detection of the speed-time profile.

According to an advantageous embodiment of the method, the control system by means of a special algorithm depending on the determined outlet rotation angle and taking into account the still to be set valves to determine a desired target angular position of the crankshaft. This can be done immediately after the determination of the outlet rotation angle or after each made valve clearance adjustment per crankshaft angle position. The optimum target angular position is characterized by the fact that this allows the setting of the valve clearance of a maximum possible number of valves still to be set. By this measure, the number of necessary positioning of the crankshaft angular position should be kept as small as possible.

To increase the ease of use, it may also be provided that the control system, in particular the control unit, for each approached angular position of the crankshaft to the operator via a display element signals which valves are in the appropriate position for adjusting the valve clearance. In addition to the valves of that cylinder, which are in the respective angular position in the dead center position for ignition, optionally a valve clearance adjustment of adjacent cylinders may be possible, especially if they are, for example, in the compression phase or discharge phase and at least the inlet or outlet valve closed is.

The signaling of the measures provided for the adjustment of the valve clearance valves on the display element of the control system, in particular the control unit, can be done for example on the basis of a graph of the internal combustion engine. This simplifies the localization of the respective valve on the engine to be serviced. The replica of the diagram is preferably carried out on the basis of the operating device from the engine control read engine parameters. Preferably, the operator can vary the display perspective of the graph, in particular in order to adapt the presentation perspective to its actual relative position to the considered internal combustion engine.

According to a preferred embodiment of the invention, the operator; mark via an input means of the control system, in particular of the operating device, those valves whose valve clearance has already been set. Preferably, the addition of such a mark for a valve is only possible if due to the current actual angular position of the crankshaft, a check and adjustment of its valve clearance is technically meaningful. This measure offers a double safety check, as the operator can thus check again whether the adjustment of the valve in the present operating situation made any sense at all. If this is not the case, the control system will again approach an angular position with the crankshaft in the remaining selections of the positions in which the corresponding valve can be set again.

Furthermore, it can be provided that the control system makes a plausibility check for a valve setting. This plausibility check can be carried out, for example, on the basis of the engine parameters available in the engine control, for example taking into account the current engine temperature, oil temperature etc. By evaluating such measured values including engine parameters, it can be ensured that the valve clearance is checked and adjusted depending on the respective ambient conditions From a technical point of view makes sense or if possibly due to existing engine temperatures outside the normal range, a valve setting could lead to a misconfiguration of the engine.

The invention further relates to a control system for carrying out the inventive method. The control system is therefore characterized by the same advantages and characteristics as already explained above with reference to the method. Preferably, the control system is composed of an engine control unit and an external operating device.

In addition to the inventive method, the present invention also proposes an operating device, which includes corresponding means and software modules for the execution of the method. In particular, the operating device comprises an interface for connection to an engine control unit of an internal combustion engine. In addition, the HMI device is equipped with a display element that can visually present the user the display of a graph or detailed information and instructions for adjusting the valve clearance.

Further advantages and features of the invention will be explained in more detail below with reference to an embodiment shown in the figures. It shows:

1 is a diagram of the valve opening widths over the crankshaft angle,

2 shows a block diagram of the system according to the invention,

3 shows a schematic representation of the graphical user interface on the control unit according to the invention,

Fig. 4: a time-crankshaft speed diagram to illustrate the speed reduction after completion of the towing process and

5: different diagram representations according to FIG. 4 for different drive units.

The invention requires motor side either no additional physical components or only a limited to the sensor retrofitting, but essentially represents only an extension of software. The software required for display and data entry by the service technician / installer is on a portable control unit, in particular computer installed, which has a data connection to the engine control unit. The majority of the additional software scope is implemented on the engine control unit.

Fundamentally, the invention is based on the following findings:

Operation I

If the drag operation of the internal combustion engine at the same crankshaft angular position phi_Starter_0ff_1 ended under the same initial conditions, then there is a reproducibility of the Ausdrehvorgangs the crankshaft, in particular results in a repetition of the process, a comparatively narrow bandwidth of the crankshaft angular positions, in the the crankshaft rotation finally comes to a standstill.

Operation II (a generalization of Operation I) Under the same initial conditions, the engine run operation is terminated in a crankshaft angular position phi_Starter_0ff_2 = phi_starter_0ff_1 + k * delta (phi_ZW), where k * delta (phi_ZW) is an integer multiple of the firing angle distance, i. is the angular difference of two adjacent firing angle, or k = 0 can be, then there is a phase-shifted to the process I reproducibility of Ausdrehvorgangs the crankshaft, in particular the crankshaft angular position in which the crankshaft rotation finally comes to a halt.

The System According to the Invention [0037] FIG. 2 shows a rough representation of the system according to the invention in the form of a block diagram. Shown is the internal combustion engine 30 of a motor vehicle, which can be started by means of a starter 40. For this purpose, a switching signal Ustarter is transmitted to the starter relay 41 by the engine control unit 10, by the switching operation of the starter is connected to the supply voltage. From the starter 40, the required drag torque is then applied to the engine 30.

In addition, the engine control unit 10 controls the fuel injectors in the regular ferry over the signals Sectors · At the same time provides the sensors present on the engine certain measurements such as the angular positions of the crankshaft PKurbei and the camshaft pack, the engine temperature T and more for the engine start release relevant signals Sx. The engine control unit also receives additional signals Sn of the rest of the vehicles, which may be relevant for engine start release.

For the inventive method, the inventive control unit 20 via the communication interface 21 with the engine control unit is connectable. The actual software functions used in the system according to the invention are for the most part and preferably completely implemented on the engine control unit 10. In this preferred embodiment, the HMI device 20 is limited as a hardware platform for the Graphical User Interface. In detail, only software functions of the engine control unit are shown, of which the inventive method makes use. Other engine control unit functions are indicated by the reference numeral 19 only. A striking feature of the system according to the invention is that a large part of the software already used for the actual engine operation as well as software-software and software-related hardware is a component of the system according to the invention.

Unlike when setting the respectively required crankshaft angular positions respectively. Camshaft angular positions according to the prior art, in which a manually operated tool is used, the inventive processing of the process takes place by interaction of the operating device 20 with the engine control unit 10 automatically. In this case, on the side of the actuator system that module 40 is used, which is present anyway for hauling up the internal combustion engine 30 for its starting process. With regard to the components, these are the 24 V starter battery, the starter 40 and the starter relay 41.

Provided that with the already existing for the actual engine application sensor detection of the direction of rotation of the crankshaft of the engine 30 is possible, such a system according to the invention without additional and without replacement of the actual engine application -. the provision of primary drive power - anyway required sensors are operated. It may be useful for an advantageous embodiment, the addition of additional sensors or replacement of sensors.

Under the condition that with the already available for the actual engine application in the engine control unit 10 signals, packing detection of the direction of rotation of the crankshaft is possible, such a system according to the invention without a supplementary signal transmission from the sensors in the engine control unit 10 (or. in the control units in which the software functions running to the engine control are implemented). Possibly, the addition of further signals makes sense for a particularly advantageous embodiment. Examples of the use of additional sensors and additional signals to illustrate a particularly advantageous embodiment of the invention are given in the following text.

The required for the actual engine application engine data set can also be used by the inventive system. To achieve further advantages, an extension of this data set is useful (s.u.).

The operation to be carried out by the service technician of the system according to the invention takes place via the control unit 20 equipped with a bidirectional data connection 21 to the engine control unit 10. This is preferably a portable computer which, via a software belonging directly to the system according to the invention, addresses at least one basic task and preferably one a graphical user interface adapted to the present type of internal combustion engine 30, which provides the service technician with the information needed and worth knowing, and allows the inputs required to perform the angular position positioning of the crankshaft. In addition, information worth knowing can be displayed and input options can be provided, which inform the service technician during the actual re-measurement and the possibly necessary adjustment of the valve latches.

A certain proportion of the software functions required anyway for the actual engine application can equally be used for the system according to the invention, in particular on condition that it is a software of modular design according to the state of the art within the engine control unit 10. As an example, the existing in the application for engine start release functionality can be used at least partially and these are supplemented in an advantageous manner. A supplement to be made for reasons of safety is that during operation of the inventive system, the operation of the ignition key in the engine start position or pressing the engine start button and any existing start-stop function are disabled (block 11), and instead the closing of the relay 41, ie the energization of the starter 40 can be triggered only via the control unit 20.

A schematic representation of the graphical user interface is shown in FIG. 3. The graphical user interface of the operating device 20 used for the corresponding maintenance provides a virtual operating button 21 with two positions A and B. In position A, there is the behavior present in the actual engine application with respect to the release and operation of the starter and other affected subsystems. In position B, there is a release and actuation adapted to the crankshaft angular position to be taken with regard to the starter and other affected subsystems. Clearly, this includes suppressing the fuel injection (FIG. 2, block 12), and in a spark-ignited internal combustion engine, no ignition sparks are generated. Depending on specific configuration features of the internal combustion engine and its periphery, further adjustments may need to be made or further adjustments may be made to represent the inventive system individually in a preferred and advantageous embodiment.

In an advantageous embodiment of the inventive system, the service technician can view on the operating device 20, the actual values of those discrete and continuous state variables that affect the current functioning or the instantaneous non-functioning of the inventive system and the influence thereon have whether favorable or unfavorable conditions exist for the upcoming maintenance. This may include: General software conditions Validation of the sensor signals used for the system according to the invention (eg crankshaft and camshaft sensor, engine oil temperature, cooling water temperature, electrical voltage, electric current and temperature of the starter battery, temperature sensor on the starter, etc.) generated signals from sensors - Detected error conditions of other participating software and software hardware In a particularly advantageous embodiment of the inventive system the service technician is displayed on the operating device 20, whether such conditions are present or in an overall view, such a system state, in which / For example, an upper threshold value could be set for the engine oil temperature, if exceeded by the service technician It should be noted that the valve train components should / should be checked for an already sufficient cooling, since the setting of valve plays at too high a temperature, as already explained in detail, is not appropriate. In this example, a warning instead of a lock seems useful, because the measured value of the engine oil temperature sensor may have a high deviation from the present at the valve train components temperature due to a completely different installation location.

Similarly, a lower threshold could be provided for the engine oil temperature, as too low an oil temperature - as explained below - is unfavorable. Whether corresponding values are displayed only quantitatively, the display of which is carried out in a quantitative and interpretive representation or only in an interpretive form, can be adapted individually. In addition, the possibility may be created that certain out-of-range values prevent the starter from operating in maintenance mode, and that lock is canceled by leaving the value (s) in the keypad or this lock remains until the relevant value (the relevant value) is reached Values) within the normal range lies (lie).

One of the most important state variables of the system according to the invention is the actual angular position of the crankshaft, which is displayed to the service technician in field 22 on the operating device 20. If this determination fulfills the requirements of the system according to the invention by the equipment present for the actual engine application, this can of course be used jointly for both functionalities; otherwise it is necessary to add or replace certain objects. If the possibility of a directly measurable or directly ascertainable absolute value of the crankshaft angular position does not exist, as described in detail in the following text, there must be the possibility of a direct direction detection of the crankshaft rotation or a reversal of direction detectable. (In a widely used method for detecting the crankshaft angular position, in addition to a camshaft sensor - to detect whether the crankshaft is in the angular range of 0 ° to 360 ° degrees or above it to 720 ° - on the outer surface of the flywheel those of a corresponding positioned sensor detectable elements attached, eg a - apart from one for the purpose of detecting a reference angular position - uniform arrangement of metal teeth, which are detected by distance sensor.It should be necessary or advantageous for the inventive system, the crankshaft angular position with a higher resolution For example, the use of an additional sensor detecting these elements and correspondingly staggered is expedient.

As a result, it is possible to achieve a distinction between four angle sections from a two-part unit consisting of a tooth and an adjacent recess along the flywheel circumference: [A] Sensor 1 detects target and sensor 2 detects I arg et [B] Sensor 1 detects Target not and sensor 2 detects target [C] Sensor 1 does not detect target and sensor 2 detects I arg et not [D] Sensor 1 detects target and sensor 2 does not detect target [0050] To enable high-resolution crankshaft angular position determination For example, the application of an analog measurement principle, if in the engine control unit 10, this analog value or a derived digital value of, for example, 4 bits (and not just a binary value) is available.

As one of many possible measurement principles, a sensor based on the Hall effect sensor can be used, which performs a "quasi-distance measurement" of the toothed jacket surface of the flywheel. The term quasi-distance measurement is intended to express that the subregion of the lateral surface influencing the sensor signal to a certain extent from a tooth (or an area portion with a small spacing) and a residual portion from a depression, i. a comparatively large distance exists.

The dynamic determination of the instantaneous crankshaft angular position can be implemented in an embodiment suitable for the system according to the invention, for example, as follows: From the recognition of the reference position of the crankshaft angular position and the summation of the respective traversed in consideration of the present directions of rotation Angular amounts, the current crankshaft angular position can be calculated. Recognition of crankshaft rotation can be achieved by using two sensors. To ensure that a reversal of direction of the crankshaft rotation is detected at short notice, the use of analog sensors whose output signals are read out via separate inputs from the engine control unit 10 is also recommended here. If only one analogue input is available at the engine control unit 10 or only one A / D converter at the measuring location, a remedy can be provided by superimposing the two measuring signals, in which case the amplitudes of the two sensors must be of different size, e.g. different preamplifications, slightly different distances to the target, slightly different sensitivities of the sensors, etc. Alternatively, an A / D conversion at the measurement location and the transmission of a signed digital signal are expedient.

With the use of two offset correspondingly arranged analog sensors is always maintaining one of the two possible directions of rotation of the crankshaft always a sequence of sequence before ... large minimum - zero crossing - small maximum - zero crossing - small minimum - zero crossing - (large maximum - zero crossing - large minimum - zero crossing - small maximum - zero crossing - small minimum - zero crossing) - large maximum - zero crossing - large minimum - zero crossing - small maximum Sequences of the reverse order are present in a continuous opposite direction of rotation. If a change of the initially existing sequence occurs, for example: ... large minimum - large minimum ..., then it is clear that a reversal of the direction of rotation has taken place. Furthermore, in the case of a direction reversal detected in this way, when an extreme value is reached or a zero crossing is reached, it is possible to deduce the exact angular position, i. a precise self-sufficient re-calibration of the crankshaft angular position determination done.

In summary, the information of the instantaneous angular position of the crankshaft must also be known in the engine control unit 10 under the influence of rotational direction changes that occur. Whether the absolute value can be determined directly or whether the value has to be calculated from intermediate quantities by means of a method that can be converted into an algorithm is irrelevant to the core idea of the invention.

Explanation of certain features of the system according to the invention by a description of its

Handling The actuation of the starter 40 for the purpose of triggering the rotation of the crankshaft for positioning the crankshaft in the respectively intended angular position is advantageously carried out by the service technician via the operating device 20; e.g. via a virtual control knob C (reference numeral 23). Taking advantage of the known actual angular position of the crankshaft and the ignition angle stored in the motor data set, the software determines and initiates a suitable time for switching off the starter 40. The actual value of the crankshaft angular position can be displayed on the operating unit 20 in the field 22, which allows a certain plausibility. If the service technician also knows the firing angle and the firing order of the internal combustion engine 30, this allows even a check. However, the service technician does not even have to have this knowledge, since the sequential crankshaft angle positioning according to the invention is already advantageously used in motor assembly and therefore a theoretically possible software error or a corresponding incorrect motor data set would be recognized at the latest during production control.

Clearly, in preparation for the actual testing and adjustment of the individual valve latches in an internal combustion engine 30 having more than one cylinder, the crankshaft must be sequentially set to a plurality of predetermined angular positions. So that the service technician is informed via the operating device 20, whether currently even more angular positions have to be approached or have already been processed all necessary, it is proposed to display the degree of execution of the already set angular positions in the field 24, such as by a numerical value displayed percentage or by means of a graphical representation.

To advantage a considerable work and avoid confusion, it makes sense that those valve symbols are marked on the control unit 20, the valve clearance can be set as intended. It makes sense for this purpose, at least a schematic representation of the engine 30 is shown, by means of which one can distinguish the two longitudinal sides of the internal combustion engine 30. For example. The indicated flywheel housing and the indicated oil filter could also be easily recognizable on the real internal combustion engine 30 and are therefore particularly well suited as orientation markers. In the diagram, therefore, the flywheel housing 25a and the oil filter 25b are indicated. The number and arrangement of the cylinders and the positions of the respective types of valves can be read from the motor data set, which may be extended in this regard, and mapped on the operating unit 20 according to their relative positions relative to each other. The position of the first and fourth cylinder is exemplified by the reference numeral 26a, 26d. The illustrated in Fig. 3 embodiment of such a view shows an example of a 4-cylinder internal combustion engine whose intake valves are each located on the side facing the flywheel of the cylinder, etc. In a particularly advantageous embodiment, the representation of the engine on the operating unit 20 of Turning service technician, whereby a comparison of the orientations between the representation on the operating device 20 and representation of the real internal combustion engine 30, which is present for the service technician, when he assumes the position in which he performs the valve clearance adjustment. As a result, the risk is reduced that due to a different orientation of the engine image on the control unit and the real engine 30, the service technician thinks to adjust the valve clearance on the valve train x, although he actually works on another valve train y. Of course, the image of the internal combustion engine 30 displayed for orientation purposes on the operating device 20 can be kept schematic and therefore simple or can be substantially more detailed.

For each cylinder, two rows of marking elements 27a, 27b, 28a, 28b are provided on the valve train images, with the element rows 27a, 27b for the marking of the outlet valves and the element rows 28a, 28b for the inlet valves. By way of the markings 27a, 28a, those valves are displayed to the service technician whose valve clearance could be set in the current crankshaft position. The markers of rows 27b, 28b may be used by the service technician to mark the respective valves (e.g., setting a hook) as soon as he has actually performed the control and adjustment on the respective valve train of the actual internal combustion engine 30.

In order to ensure that during the corresponding maintenance of the internal combustion engine, all the valve clearances are remeasured and, if necessary, readjusted, and that this is done according to the intended purpose - i. E. In the case of a crankshaft angular position, in each case only those valve drives in which the associated valves are closed, the following procedure must be followed, according to current maintenance regulations with a crankshaft positioning which corresponds to the state of the art:

The crankshaft is set in an angular position corresponding to an ignition angle phi_ZWi. (In this case, a deviation of the setting by a few degrees is tolerable). Then only the valve clearance for the cylinder i associated valve trains are set. This procedure is done for each cylinder. As is known to the person skilled in the art, a cam contour-irrespective of whether it is an expression with a flat, steep or asymmetrical cam-has an angular range comparatively large relative to its axis of rotation, over which the contour runs in a circle. Meanwhile, there is a tap along the circular portion of the cam contour, the valve associated with this tap is completely closed. As a result, in the presence of the crankshaft angular position, which corresponds to the ignition angle phi_ZWi of the cylinder i, by no means only the inlet and exhaust valves of the cylinder i (completely) closed or closed. not only are the valve trains of the cylinder i in such a current position in which a proper setting of the valve clearance would be possible.

However, the service technician does not know per se these corresponding relations between the firing angles and closed valves. (This applies in particular to the great variety of types and subconfigurations of internal combustion engines of the off-road segment, which are used, for example, in mobile work machines.) In the system according to the invention, reading out of the data set stored in the engine control unit with one within the Maintenance software running data processing this engine-specific relation can be determined and the control unit can display all the valve symbols depending on the current crankshaft angular position, the respective valve clearance setting on the real internal combustion engine can be made as intended.

If the said database is not already contained in the motor data set for the actual motor application, it can of course be extended with these parameters.

With knowledge of this database, the optimization algorithm contained in the software of the system according to the invention (FIG. 2, block 13) makes it possible to minimize the number of crankshaft angular positions to be set in order to be able to set all valve plays as intended. Before a detailed explanation of this relationship, the process that can be experienced by a service technician is given by the example of a 4-stroke 4-cylinder internal combustion engine with a conventional design with respect to its firing angle and firing order: 1. After the operational readiness of the system according to the invention, the service technician activates the control knob C of FIG Control unit 20. 2. After the end of the first positioning the service technician on the control unit 20 via the element rows 27a, 28a symbolizes that he can adjust the valve latches of the intake valves of the cylinders 1 and 2 and the valve latches of the exhaust valves of the cylinders 2 and 3. Assuming an acknowledgment of the corresponding valve trains by means of the elements in rows 27b, 28b, the operation continues as described. 3. The service technician again presses the operating button C. 4. After the end of the second positioning, the service technician is again marked on the operating unit 20 (element rows 27a, 28a), that he / she can read the valve latches of the intake valves of the cylinders 3 and 4 and the valve latches of the outlet valves the cylinder 1, (2) and 4 can adjust.

Not perceptible to the service technician, the following has taken place: During each positioning process, a crankshaft angular position sets in which corresponds to the ignition angle of a cylinder i. Assuming that in the first operation, the crankshaft has come to a standstill on the ignition angle of the cylinder 2, the maintenance software determines the valvetrains displayed or to be displayed under point 2. The optimization algorithm 13 determines the desired value of the crankshaft angular position for the subsequent positioning process. In the given example, this is the firing angle of the cylinder 4. Once this positioning has been carried out, the maintenance software determines the valve trains to be indicated or indicated under 4..

The optimization algorithm 13 is used by the software main routine before the second and each further required positioning operation of the crankshaft. For the respective internal combustion engine, the optimization algorithm 13 determines from the entirety of all ignition angles that from, under which, if the crankshaft angular position is positioned on this, a maximum number of not yet checked / set valve clearance can be checked / adjusted as intended. This optimum firing angle then represents the target position of the end position to be achieved at the next crankshaft positioning.

Why the optimization algorithm 13 can be applied only from the second crankshaft positioning, can be deduced from the following text. In the above example of the four-cylinder internal combustion engine 30 results - assuming that after the first shutdown of the starter 40, the initially continuing and decaying rotation of the crankshaft finally comes to an angle near the firing angle phi_ZW2 of the cylinder 2 angular position - using the said optimization algorithm 13, that the firing angle phi_ZWA of the cylinder 4 is optimal from the set of firing angles {phi_ZW1, phi_ZW2, phi_ZW3, phi_ZW4}. By the subsequently executed by the software routines, the control of the starter 40 is calculated, actually switching off at the correct crankshaft angular position, so that this target state occurs, i. a positioning of the crankshaft angular position on the ignition angle phi_ZWA is done. To trigger this procedure, the service technician on the HMI device 20 must only press the virtual button C. After the automatic completion of crankshaft positioning on the actual internal combustion engine 30, those valve symbols 27a, 28a on the operating device display are marked which correspond to those valve drives on the actual internal combustion engine 30 whose valve clearance can be set as intended.

Regardless of whether the normal case namely the achievement of the target angular position or the possibly not completely excluded missing of the target angular position occurs, is from the software -. via an evaluation of the signals emitted by the crank and camshaft sensors, packing - the actual actual angular position of the crank-shaft end position detected.

In the case of such a detected high deviation between the actual and the desired angular position, it is indicated on the operating device 20 that the service technician should immediately actuate the operating button C again.

Alternatively, the flow determined by the software in this use case be designed so that even when missing the desired angular position those valve trains are marked on the control unit 20, the valve clearance due to the actual angular position can be set as intended, although the present actual angular position does not coincide with the nominal angular position. If this or some of these valve train positions are acknowledged via the operating device, then these valve games are also considered as adjusted, which is taken into account in the subsequent run of the optimization algorithm 13.

In a preferred embodiment of the inventive system, the acknowledgment exclusively such valve train positions is possible, the valve clearance on the real engine 30 due to the present and known crankshaft angular position can be adjusted appropriately. In a particularly preferred embodiment, the valve train positions already acknowledged during a sequence also remain acknowledged when a repositioning of the crankshaft angular position has been carried out in the course of the sequence processing. In a further improved embodiment, the status can be reset by the service technician on the operating unit 20 for one or more valve positions in unacknowledged.

Regarding the Optimization Algorithm 13 As stated, the crankshaft rotating out after the starter has been shut off comes to a halt in an angular position within a bandwidth encompassing a specific ignition angle phi_Zwi. If the first positioning operation of the crankshaft is carried out with the system according to the invention in the course of maintenance for checking and possibly adjusting the valve latches, the ignition angle phi_Zwi_1 is not known in the vicinity of which the angular position of the crankshaft comes to a standstill until immediately before the end of the boring process becomes. Therefore, the sequence of optimum ignition angles to which the crankshaft is subsequently to be sequentially positioned depends on the ignition angle phi_Zwi_1, which has been set in the first positioning process. In combustion engines with eight or more cylinders, there is a large number of different optimal sequences in view of these many possibilities. In the case that the crankshaft is not positioned at an angular position within the bandwidth of the desired ignition angle, the sequence of optimum ignition angles may change again for the remaining positions; also if already acknowledged valve positions are reset to the status not acknowledged.

For the reasons stated, an online operation of the optimization algorithm 13, i. an implementation in the run during maintenance software over the alternative to apply the optimization algorithm in the run-up to the application to calculate the sequences and the latter, for example, store in the motor data.

Reproducibility of the towing process For the positioning of the crankshaft according to the invention in a specific angular position, the starter 40 is operated in each case only for a few seconds. Within such a short period of time, no sustained lowering of the power output of the vehicle battery occurs. (By this is meant that the power output capability of the vehicle battery is dependent only on the instantaneous value of the battery voltage - which decreases due to the high battery current - but not on an already influential previous battery discharge.) A period in which the engine 30 is towed by the starter 40 , each extends over a few seconds. Therefore, the heat energy released during such operation in the (clearly non-fired operation) of the internal combustion engine 30 is correspondingly low in relation to the heat capacities therein and therefore there is no application-related temperature increase that could cause such an effective viscosity change of the engine oil. In addition, between two positioning operations of the crankshaft results in a certain period of time, namely in which the setting of the valve latches is performed. Over this period of time takes place a regeneration of the starter battery, which is based essentially on their cooling.

Traction Procedure and Crankshaft Shutdown After Starter Shutdown As the service technician on operator panel 20 of the system already in the appropriate service mode operates the engine crank button C, the crankshaft of the engine 30 is rotated by the starter 40. After a short time of about one to max. five seconds results in a periodic speed curve. Likewise, the drag output from the starter 40 to the engine 30 is periodic. In a simplified consideration arises due to the increasing friction with increasing speed in a very rough approximation, a constant towing speed resp. Crankshaft speed.

In the timing diagram of Fig. 4, the crankshaft speed is plotted against the time t. The starter 40 is operated at a time t <0 for the duration L. After a short time, i. from the time t = 0, there is a speed variation existing by a DC component, as shown qualitatively in FIG. 4 in the left-hand part of the speed-time profile. During a certain period of time or a specific crankshaft angle range, a compression phase is present in one cylinder (or, in the case of an internal combustion engine with a correspondingly high number of cylinders, this can also occur over several cylinders), which clearly leads to a reduction in speed. When the crankshaft is rotated past the ignition angle of the cylinder in question, the state of the cylinder in question immediately enters the expansion phase and remains over a certain crankshaft angle range. Within the last defined angular range carries a high proportion of the previously constructed compression energy to an acceleration of the crankshaft, respectively. to a speed increase. (Another part occurs in the course of the friction present in the cylinder and a further part emerges in the course of the previous compression as heat from the relevant system.). The speed period is calculated as the quotient of the crankshaft speed and the number of different firing angles and a factor f. For a 2-stroke motor, the factor is 1; for a 4-stroke engine, f = 0.5.

After a periodic speed profile is present, the power supply of the starter 40 is interrupted at a selectable but precisely defined crankshaft angular position by specifying a belonging to the inventive system software function. In the diagram, the period with deactivated starter 40 is marked as f.2. In this section t2, no power is supplied to the rotating mass system from the outside (from the starter 40). Due to the energy still present in the system, the cyclic rotational movement continues with decreasing speed-time profile over a certain period of time. During the first crankshaft positioning operation, for example, the current supply of the starter 40 could be switched off exactly upon detection of the reference position on the flywheel. However, no position should be selected in which one of the cylinders is at a dead center or an angular position close thereto. Switching off in a firing angle position or a slightly smaller angular position would be particularly unfavorable. As mentioned, from the second crankshaft positioning operation, the turn-off instruction of the starter 40 is determined by the optimization algorithm 13.

If the starter 40 is switched off in the presence of the same speed-time profile and at the same crankshaft angular position, then there is a reproducible amount of rotational and compressive energy at the time of shutdown in the considered rotating mass pneumatic system. There are three main influences for the speed profile taking place during the decay process t2, which are reproducible with relatively high accuracy under the same environmental conditions. a) The friction: Dependence on the speed and the crankshaft angular position. (The temperature-related influence on the friction is reproducible during the intended use of the invention.) B) By the piston movement in the temporarily closed valve channels of a cylinder in the present mechanical-pneumatic system, an energy exchange between compression and rotational energy. Therefore, during the general trend of a speed decrease, there are periods (or angle ranges) in which a speed increase takes place. Likewise, there are periods (or angle ranges) in which a particularly strong speed decrease takes place. c) The air trapped in the cylinder is no longer completely released during the decompression phase during the decompression phase to overcome the friction and acceleration of the rotating mass system, but some heat is removed (mainly through the cylinder liners).

When the rotational speed has decreased sufficiently, the rotational energy of the rotational mass system, which has sunk as a result, is no longer sufficient to apply the compression energy required to exceed the immediately following ignition angle. In this case, the crankshaft rotates to that angular position in which the rotational energy is used up. If a compression energy of sufficient magnitude already exists in this angular position for the application of the breakaway torque of the crankshaft, the direction of rotation of the crankshaft is reversed immediately. Due to the reversal of direction takes place now in another cylinder, the compression of air. This process can occur several times in succession before the rotation of the crankshaft finally comes to a standstill at the time T4. Within the period tβ, the occurrence of each of the rotational reversals is indicated by arrows. It should be noted at this point that the supposedly from the diagrams to be recognized periods between the speed extrema and the speed zero crossings are not reproduced to scale.

Decisive for the system according to the invention is the knowledge of i) the crankshaft angular position which it has assumed at the end of a positioning process. ii) the total number j of firing angles that have been completely overcome after the starter has shut down.

For the meaning of the term completely overcome: If, when turning the crankshaft out of the direction of rotation in which an acceleration is possible by the starter, at an angle which has approximately the value of the ignition angle phi_ZWi to stop, so is the simpler case A before.

In the other case B, for example, during firing, the firing angle phi_ZWi can initially be overcome, but the firing angle subsequent to the further rotation no longer exists. If there is a change in the direction of rotation, the ignition angle phi_ZWi can certainly no longer be overcome. If the crankshaft rotation finally comes to a halt during this last-mentioned movement, this occurs at an angular position which is slightly greater than the ignition angle phi_ZWi.

In the given but generally held example, the firing angle phi_ZWi in case A can not be completely overcome and also not in case B. Further, the example shows that the positioning of the crankshaft is not limited to exact firing angles but within a firing angle Bandwidth occurs.

Within the range of the oil temperature which is permissible for this type of maintenance-checking and possibly adjusting the valve latches-the required energy fractions which, in order to overcome the ignition angle, are substantially greater than the proportions for overcoming the mechanical friction. After a shutdown of the starter 40, therefore, the crankshaft always reaches such an end position, which is in relation to the before coming to a stop the decaying rotary motion close to the exceeding of an ignition angle, wherein the final angular position, depending on the immediately preceding to stop rotation direction slightly smaller is slightly larger than a firing angle.

Clarification on the basis of a simple notional numerical example It is an internal combustion engine with the following ignition angles: phi_ZW1 = 60 °, phi_ZW3 = 240 °, phi_ZW4 = 420 ° and phi_ZW2 = 600 °.

Already at the beginning of this imaginary process, the turning out of the crankshaft is almost complete, since the energy contained in the considered rotary mass pneumatic system is almost used up. Furthermore, the crankshaft rotates in the direction of rotation that would be impressed on it by the towing with the starter 40. Scenario 1: The crankshaft can no longer overcome the ignition angle phi_ZW1 = 60 ° of the cylinder 1 and comes in the angular position of, for example 50 ° to a stop.

Scenario 2: The crankshaft can no longer overcome the ignition angle phi_ZW1 = 60 ° of the cylinder 1, and at an angular position of, for example, 55 °, the direction of rotation is reversed. As a result, an expansion of the previously compressed air takes place in the cylinder 1. As a result, the crankshaft rotates beyond the angular position of 0 ° and moves into the angular range in which, due to the present direction of rotation in the cylinder 2, air compression takes place, and remains at the angular position 610 °, for example.

If this occurs to stop the crankshaft rotation starting from the regular direction of rotation of the internal combustion engine, this is done at an angular position which is slightly smaller than a firing angle. If this happens from the opposite direction of rotation, a standstill of the crankshaft occurs at an angular position which is slightly larger than a firing angle.

Switching off the Starter at the Crankshaft Angle Position phi_Starter_Off_0 [0090] If the engine's rotational mass system rotates after the stabilization of the towing operation with the same speed-time profile or simply the same average engine speed, the starter 40 rotates at the same crankshaft speed. Angular position phi_Starter_Off_0 switched off, there are reproducible amounts of rotational and compression energy in the system to be considered. However, the sequence that proceeds from this initial situation of the examination can also be reproduced, and in terms of rotational energy, the compression energy and the angular velocity, reproducible time courses and equally reproducible courses of these three quantities above the crankshaft angular position result. This results in a relatively narrow-sized interval of several full revolutions cumulative total angle phi_KW_sum_0 by which the crankshaft after switching off the starter continues to rotate until the rotational movement - after possibly multiple direction of rotation reversal - comes to a standstill and therefore is for a relatively narrow-sized Bandwidth of the end position of the crankshaft angular position phi_KW_final_O a very high reproduction rate before.

The same situation can alternatively be described: After the starter 40 has been switched off, the turning of the rotary mass pneumatic system takes place under a complete overshoot of (n-1) ignition angles, whereas the following ignition angle can no longer be completely overcome. For reproducibility of the ignition angle which is no longer completely overcome, the angular position at which the starter 40 is switched off may be decisive. Consequently, an exact adherence to the crankshaft angular position, in which the shutdown of the starter 40 takes place, is recommended. (Clearly, it is very easy to maintain the angular position in which the starter is to be cut off, but the torque output by the starter 40, even when it is stationary, is not independent of the angular position of its rotor Asymmetry also for the inventive system in terms of application is irrelevant.) As already stated, the end position of the crankshaft is always in a range of such angular positions, in which a cylinder (or in internal combustion engines with a corresponding number of cylinders more cylinders) with respect to last direction of rotation is in the compression phase (are).

Switching off the starter at the crankshaft angular position: phi_Starter_Off_i = phi_Starter_Off_0 + k * delta (phi_ZW) If after the presence of a stabilized towing operation, the starter 40 in another crankshaft angular position phi_Starter_Off_i = phi_Starter_Off_0 + k * delta (phi_ZW ), where k * delta (phi_ZW) is an integer multiple of the firing angle distance, ie the distance between two adjacent firing angle, the respective internal combustion engine 30, then takes place due to the present with respect to the present on the Zündwinkellagen symmetry of the considered rotary mass pneumatic system with respect to the turn-off of the starter 40 is only a phase shift, but otherwise the same sequence as when switching off the starter 40 at the crankshaft angular position phi_Starter_Off_0 before. Such a symmetry of the rotational mass system is present because the flywheel represents by far the largest share of the total moment of inertia of the rotational mass system and the crank mechanism also represents a symmetrically balanced rotational mass system due to uniformly distributed firing angle and thus overall there is a nearly rotationally symmetric rotational mass system. A symmetry of the pneumatic system is due to uniformly distributed ignition angle and due to the ignition angle of any cylinder i before the same valve lift curves of the cylinder i associated intake and exhaust valves. Since the phase shift is an integer multiple of the ignition angle distance, the crankshaft reaches an end position in the angular position phi_KW_final_i = phi_Starter_Off_0 + k * delta (phi_ZW) + phi_KW_sum_0.

In summary, provided that comparable starting conditions exist:

If the starter 40 is switched off in the crankshaft angular position phi_Starter_Off_0, whereby a number of (n-1) ignition angles are overcome at the end of the crankshaft rotation and finally the crankshaft comes to a standstill within a narrowly determined bandwidth of the following ignition angle, then switching off the Starter 40 in the angular position phi_Starter_Off_i = phi_Starter_Off_0 + k * delta (phi_ZW), where k * delta (phi_ZW) is an integer multiple of the Zündwinkelsabstandes, to the fact that the crankshaft comes to a standstill in a narrow range of the nth firing angle.

Application of the relationship to the angle specification for switching off the starter Option 1: Calculation using angle values [0096] At the beginning of a maintenance, there is no information about the value of the total angle phi_KW_sum_0 (see above). (During maintenance, it can be assumed that the initial conditions change negligibly and therefore a reproducibility of the turning operation of the crankshaft is present.) However, it can not be assumed that the starting conditions are the same for the various types of maintenance.) Therefore, the starter 40 is switched off for the first time predefined value phi_ Starter_Off_0. (With respect to the firing angles, restrictions and recommendations have been given in the previous text on which angular range phi_Starter_Off_0 should be selected.) As soon as the first positioning operation is completed within a maintenance, it is possible to use the sensor system according to the invention and in the system according to the invention associated software implemented calculation of the value phi_KW_final_O be determined.

If the pair of values (phi_Starter_Off_0; phi_KW_final_O) is known and the optimum ignition angle phi_KW_final_optvor determined by the optimization algorithm 13 is present, the respective next crankshaft angular position in which the starter is stopped for the purpose of positioning the crankshaft after reaching a stationary towing operation should be calculated in a simple way. In an idealized but practicable consideration, an angular difference of the same magnitude exists between the end positions of the crankshaft angular positions phi_KW_final_O and phi_KW_final_opt as between the known crankshaft angular position phi_Starter_Off_0, in which the predefined deactivation of the start took place and the crankshaft angular position phi_Starter_Off_opt to be determined. The following applies: phi_Starter_Off_opt = phi_KW_final_opt - phi_KW_final_0 + phi_Starter_Off_0 Alternatively, using the determinable cumulative total angle phi_KW_sum_0 comprising several full revolutions, the angular position phi_Starter_Off_opt, in which the startup has to be switched off, can be calculated to phi_Starter_Off_opt = phi_KW_final_opt - phi_KW_sum_0 Option 2: Calculation of the number of ignition angles exceeded [0099] After the starter 40 has been switched off, the number of ignition angles exceeded in the system according to the invention could be counted up during the boring process, it being ensured that in such a count the firing angle phi_KW_final_i comes to a standstill in the vicinity of the crankshaft is counted exactly once.

The two explained possibilities show by way of example that with the above-described embodiments of the system according to the invention, it is possible to determine such crankshaft angular positions, in which the starter 40 is switched off in each case to position the crankshaft in a targeted manner.

In a mobile work machine, there is usually between the crankshaft of the primary drive internal combustion engine 30 and drives that absorb high levels of drive power, e.g. the drive shaft of a hydraulic pump, a compound that can not be separated via a coupling. Often, several hydraulic pumps are present here, whose drive shafts are each connected via individually adapted fixed gear ratios via a so-called pump distributor gearbox with the crankshaft of the internal combustion engine 30. Such a unit, consisting of the primary drive serving as the internal combustion engine 30, the pump distributor gearbox and the hydraulic pumps driven above, is often referred to as a drive unit.

Of course, this situation naturally exerts an influence on the system according to the invention. In the case of a drive unit is a rotary mass pneumatic hydraulic system. However, this does not constitute a hindrance to an application of the inventive system in the field of mobile work machines. Because the starter device must obviously be designed per se to fulfill its basic function, namely to tow the engine on the occasion of engine start accordingly high performance. In this respect, the concerns are also covered in this respect for the inventive use of the starter device.

The additional torque to be applied in towing mode due to the hydraulic pumps to be rotated is essentially dependent on the rotational speed and the temperature of the hydraulic oil, but almost independent of the drive shaft angular positions of the existing hydraulic pumps. The reason for the latter is that in a hydraulic pump under supply of mechanical power, a continuous flow of the medium hydraulic oil from the suction side (negative pressure side) to the top pressure side and thereby, in contrast to the cylinders of the internal combustion engine 30, which represent respective energy storage in the process under consideration In the case of hydraulic pumps, there is no behavior of an energy store. The built-up oil pressure is clearly under energy. However, the presence of the oil pressure results in the occurrence of oil leakage and while there is no feedback of hydraulic power to the rotary mass system.

It is clear that under the same starting conditions (component configuration of the engine 30, towing speed & engine oil temperature) in the application of the inventive system in an internal combustion engine 30 after shutdown, the crankshaft crankshaft extension lasts longer than that of an identical internal combustion engine engine the case is. Assuming that the crankshaft speed-time profile has the qualitative course of the above arranged diagram of FIG. 5, then would be for an identical but built in a drive engine internal combustion engine 30 at moderate additional towing load tends the middle or in the case of a high additional towing load in the lower Chart shown crankshaft speed time profile result. Such a rapid decay of the Ausdrehens, which significantly reduces the reproducibility of this process is therefore excluded, because due to the concerns of the actual application of an internal combustion engine used in a drive unit at higher tractor load with a larger flywheel (ie a flywheel with a higher moment of inertia) are equipped would, and this measure also the reliability of the inventive system directly benefits.

The damage of in the drive unit associated hydraulic pumps is not to be feared by the use of the inventive system, since the rotation in the operation not intended direction only takes place at low speeds and in each case only for very short periods persists. In addition, such a reversal of rotation when switching off the internal combustion engine after the end of each work operation of the mobile work machine done. In the field of mobile work machines, hydraulic pumps are often used, which can be operated normally in both directions of rotation anyway.

The following expansion stages of the invention are also conceivable: So that no one unauthorized or unintentionally actuates the starter 40 via the operating device 20 while the service technician performs the actual setting of the valve games, the operating device 20 the possibility of a software-based locking by the operation of another virtual Control button provided. If this lock exists all other functionalities of the inventive system are retained; In particular, the valve positions can be acknowledged, which are intended to mark the positions of the set valve clearances. Unlocking can be done by simultaneously pressing two or three virtual control buttons or by entering a password.

Other graphic elements for marking valves on the graphical user interface are conceivable. These can be used to silence those valve positions whose valve clearance has been knowingly set correctly.

Display / display option of the discrete and continuous state variables can be provided, which have an influence on the current functioning or the instantaneous non-functioning of the system according to the invention and / or warn that due to the present state, the setting of the valve latches may could not be effective.

When using the system according to the invention, a further operating state is introduced with regard to the engine control since the original operating state in which starting of the internal combustion engine 30 can take place has to be modified to the interests of the invention, e.g. that the energization of the starter 40 is not triggered by the ignition key, but via the control unit 20 and that no fuel injection takes place. The maintenance scope of an adjustment of the valve latches can in turn be subdivided into two sub-states: a) The crankshaft positioning b) The actual setting of the valve latches Depending on the equipment and the structure of the system present for the actual ferry operation, it can be advantageous or even advantageous for the system according to the invention It may be necessary for further functions contained in the overall system to be adapted to the sub-states a) and b) with regard to their operating behavior. An example of this would be any electrically powered engine lubricating oil pump. In state a), operation of this pump is useful, as before an imminent engine start. In the state b), however, a shutdown of the pump is advantageous so that during the adjustment and measurement of the valve plays the valve trains are not permanently wetted by new hinzuströmendem oil.

Also, other software functions for initiating the starter shutdown timing in crankshaft positioning are possible. Upon release to disable the starter, the starter 40 is turned off upon reaching a crankshaft angular position to be determined by the software. The release criterion can be displayed in different stages of development. In a simple version, release takes place after the starter 40 has been operated for a certain period of time. In this case, this period of time of the order of magnitude of a few seconds is selected to be correspondingly large, so that according to experience a periodic speed-time profile is present. Alternatively, the release for the shutdown of the starter by the service technician can be made within a certain time window. The actual shutdown of the starter 40 is also initiated here by the software to ensure reproducibility.

In an expansion stage, the output signal of the crankshaft sensor can be evaluated, e.g. by using the autocorrelation function. If the starter battery is equipped with a sensor, the time course of the battery voltage or, if present, the time course of the battery current can be used to detect the presence of the stationary towing operation, since the load increased during a compression phase and the load reduced during a decompression phase is also in show the actual values of the electrical measured quantities.

In summary, the invention provides the following advantages: The positioning of the required crankshaft angular positions is triggered by the service technician via an operating device 20, preferably a portable computer which is anyway required for engine diagnosis, and takes place automatically.

[0114] The currently required crankshaft angular positions are determined by the software. The service technician does not even have to look for these values in a maintenance book and enter them into the operating device 20, which prevents any confusion in this regard.

In the crankshaft angular positions to be determined by the system according to the invention, an optimization algorithm 13 is used. This allows the valve clearance to be adjusted with a minimum number of crankshaft positioning, even though the service technician may want to selectively repeat certain valve lash settings. The optimization algorithm 13 prevents the complete procedure of the crankshaft positioning having to be repeated in the case of a failure of a certain desired angular position of the crankshaft, which can not be completely ruled out.

The positions of those valves whose valve clearance can be set as intended are displayed to the service technician on the operating device 20.

The system according to the invention offers further functionalities which greatly reduce further risks of confusion: acknowledgment and remaining indication of valve positions at which the valve clearance has already been set. The arrangement of the elements to be displayed on the operating device 20 depends on the arrangement of the real elements on the internal combustion engine 30. The orientation of the combustion engine 30 depicted on the operating device 20 can be adjusted to the actual view of the actual internal combustion engine 30, that of the service technician on the latter has when he operates the HMI device 20. The engine 30 can be inspected only from one side. It can be seen on the engine shown in the display (FIG. 3) that the left flywheel 25a and the oil filters 25b are located on the right side. Assuming from the perspective of the real internal combustion engine 30 would have a different installation orientation and the possibility of an orientation adjustment on the operating unit 20 is not given. Then the service technician would have to constantly pay attention to the opposite arrangement that exists in the real motor and its mapping on the HMI device.

The use of the inventive system is particularly advantageous in mobile machines because their maintenance is almost exclusively at their place of use. During maintenance often comes the entire

Process in which the mobile work machine is involved to a halt. Consequently, a speedy completion of maintenance is of particular importance.

For the system according to the invention, no additional components in the field of actuators are needed.

For the system according to the invention certain software modules, which are already present for the actual engine application, can be shared. The additional software scope can largely be implemented on the engine control unit 10, to the extent that only the software interface and the graphic elements are accommodated on the operating device 20.

The inventive system solution can be used without additional costs for future generations of engines and even be used for the existing engine inventory, provided that the sensors used to detect the crankshaft angular positions meets the requirements set out above. If the latter is not the case, only retrofitting that is limited to this sensor is required.

In total, an extremely high time savings, significantly more comfortable working conditions and a contribution to avoid confusion are achieved.

The inventive method can be applied to all types of reciprocating engines, the valve train is triggered by the rotation of a camshaft and regardless - of the exact structure of the valve train - the number of cylinders - 2-stroke or 4-stroke - the fuel used - Of the engine application (stationary, mobile, maritime, etc.) In particular, the method can also be applied to existing internal combustion engines by the additional software functions required for the inventive system are subsequently added or implemented on the existing engine control unit.

In general, the process execution during assembly, a general overhaul of the engine, a service case (maintenance or repair) in a workshop or as usual in mobile work machines in the field is conceivable.

Claims (16)

claims 1. A method for automatically positioning the angular position of the crankshaft and / or camshaft of an internal combustion engine for adjusting the valve clearance, wherein by means of a control system, a drag torque is applied to the internal combustion engine to position the crankshaft in a defined angular position in which the valve clearance of one or several valves of the internal combustion engine is adjustable. 2. The method according to claim 1, characterized in that is driven to generate the drag torque of the starter of the internal combustion engine. 3. The method according to any one of the preceding claims, characterized in that the control system comprises at least one engine control unit and / or at least one additional operating device, wherein preferably a large part and particularly preferably all the necessary control functions for the execution of the method are implemented on the engine control unit and the operating device forms the visual input and output interface of the control system. 4. The method according to any one of the preceding claims, characterized in that by means of the control system prior to the execution of a method deactivation of an ignition key function and / or engine start button and / or automatic start / stop and / or fuel injection and / or spark ignition of the cylinder he follows. 5. The method according to any one of the preceding claims, characterized in that it is an external device in the operating device, which is connectable via a communication interface with the engine control unit of the internal combustion engine and reads from this necessary engine parameters or any control functions of the engine control unit, such as ., the actuation of the starter, triggers. 6. The method according to any one of the preceding claims, characterized in that the actual angular position of the crankshaft is detected directly or indirectly by a sensor on the crankshaft and / or the flywheel and / or the camshaft or calculated from one or more measured values. 7. The method according to claim 6, characterized in that, taking into account the actual angular position of the crankshaft and in dependence of a firing angle of the deactivation point for the deactivation of the starter is determined. 8. The method according to claim 6 or 7, characterized in that it is determined at the beginning of the process to which outlet rotation angle the crankshaft after deactivation of an applied drag torque, in particular switching off the starter continues to rotate, taking into account the outlet rotation angle, the exact angular position is determined at which is achieved by switching off the drag torque and leakage of the crankshaft, the desired desired angular position of the crankshaft. 9. The method according to any one of the preceding claims, characterized in that the starter is driven at least until a periodic speed-time profile is present, wherein the presence of a corresponding operating profile preferably determined based on the crankshaft speed and / or the supply voltage or current of the starter becomes. 10. The method according to any one of the preceding claims, characterized in that the control system determined by means of a special algorithm in dependence of the determined outlet rotation angle and taking into account the valves yet to be set angular position of the crankshaft, the setting of the valve clearance of a maximum number of still to be set Valves allows. 11. The method according to any one of the preceding claims, characterized in that the control system, in particular the control unit, for each approached angular position of the crankshaft the Bedienet 'signals for which valves in the respective angular position, an adjustment of the valve clearance can take place. 12. The method according to claim 11, characterized in that the signaling takes place by means of a on a display element of the control system, in particular the control unit, superimposed graph of the engine, wherein the operator can adjust the display perspective of the graph, preferably to its relative position relative to the engine, and wherein the graph image is preferably generated based on engine parameters read out by the engine control unit. 13. The method according to any one of the preceding claims, characterized in that the operator can mark on an input means of the control system, in particular of the operating device, those valves for which an adjustment of the valve clearance has been carried out, wherein preferably a marking of the valves is only possible if their valve clearance is adjustable in the current actual angular position. 14. The method according to any one of the preceding claims, characterized in that a check is made by the control system, whether a measurement and adjustment of the valve latches on the basis of the engine parameters available in the engine control makes sense, for example, taking into account the engine temperature, oil temperature, coolant temperature. 15. Control system for carrying out the method according to one of the preceding claims. 16. External control device for carrying out the method according to one of the preceding claims.