DE102010009383A1 - Method for the individual operation of an internal combustion engine, and control device for an internal combustion engine - Google Patents

Abstract

The invention relates to a method for individually operating an internal combustion engine of a single motor vehicle, the internal combustion engine having at least one valve lift adjustment device for at least one valve, and the valve lift adjustment device being controlled / regulated in such a way that the fuel consumption of this internal combustion engine at a given operating point is as low as possible or is comparatively low as possible. Furthermore, the invention relates to a control device for an internal combustion engine of a motor vehicle, which is designed such that a method according to the invention can be carried out and / or is carried out by the control device.

Description

The invention relates to a method for the individual operation of an internal combustion engine of an individual motor vehicle, wherein the internal combustion engine has at least one valve lift adjusting device for at least one valve, in particular an inlet valve. Ie. The invention also relates to a method for the individual operation of a valve lift adjusting device of an internal combustion engine. Ie. Furthermore, that the invention relates to a method for Hubadaption, in particular a Kleinsthubadaption, a variable Ventilhubsystems or a valve lift adjustment. Furthermore, the invention relates to a control device for an internal combustion engine of a motor vehicle, which is designed such that by the control device, an inventive method is feasible and / or performed.

A control and / or regulation of internal combustion engines is usually carried out by means of an electronic control device (engine control unit ECU). The control device is connected to actuators or actuators and sensors of the internal combustion engine. By transmitting appropriate control signals to the actuators, the operating parameters and manipulated variables of the internal combustion engine, such. B. throttle angle and ignition timing, adjusted such that the torque produced by the engine corresponds to a torque request of a motor vehicle driver. The advantage of the electronic control / regulation is that the manipulated variables can be optimized with regard to the efficiency and pollutant emissions of the internal combustion engine.

In the control device, control functions in the form of software are implemented, which resort to an extensive database, mainly in the form of maps. A mapping of the maps is usually done on engine test beds or during test drives. However, the number of test motors on which the rating is made is very limited. However, the data obtained are used for all engines of this type. Due to manufacturing tolerances and due to changes over the lifetime of a particular internal combustion engine, it may be that the database obtained on the few test engines is not always an optimum for each individual internal combustion engine. This gives away power and consumption potential.

Previous valve lift adjusting devices for internal combustion engines usually have only one adjustment possibility of the relevant valves for all cylinders simultaneously. However, the filling differences of the cylinders increase with decreasing strokes of the valves. So far, this problem is encountered such that a sensor, the various effects of increasing filling differences, such. B. cylinder-selective lambda detection, cylinder-selective smoothness detection, cylinder pressure, vibration sensor o. Ä. Recognizes. By means of a control or regulation, a minimum lift adaptation is carried out, with a minimum lift of the valve being reduced until an acceptance threshold is reached which is defined by an acceptable smoothness or a level of the ignition interventions or permissible lambda deviations of the individual cylinders. Such methods are known from DE 101 56 409 A1 , of the DE 102 59 846 A1 or the EP 1 193 381 known.

It is an object of the invention to improve a control or adjustment of an individual internal combustion engine and to provide a corresponding control device. Here, on the one hand a corresponding device of the internal combustion engine to be identified and on the other hand, this device can be individually optimized or improved according to a criterion.

According to the invention, it should be possible to dispense with a cylinder-selective sensor technology or evaluation functionality, wherein it is desirable if the method also works correctly in the case of a malfunction of a lambda probe, a crankshaft position sensor, a vibration sensor or a cylinder pressure sensor. Furthermore, the method should be resistant to aging of the internal combustion engine, d. H. Aging effects of the internal combustion engine or the corresponding device of the internal combustion engine should be permanently compensated reliable. In addition, in application of the invention to a gasoline engine, this at least partially unthrottled operable even at low speeds.

The object of the invention is achieved by a method for the individual operation of an internal combustion engine of a single motor vehicle, according to claim 1; and a control device for an internal combustion engine of a motor vehicle, according to claim 11 dissolved. Advantageous developments of the invention will become apparent from the dependent claims.

According to the invention, such a device is a valve lift adjusting device and a criterion according to the invention a fuel consumption. In this case, according to the invention, a specific internal combustion engine is operated in such a way that its valve stroke adjusting device is controlled or regulated such that the fuel consumption of the internal combustion engine is minimized, optimized, reduced or comparatively reduced. The valve lift adjustment is doing for the inputs and / or Exhaust valves of a single, a plurality or all cylinders of the internal combustion engine responsible.

A basic idea of this method is to optimize the fuel consumption of the internal combustion engine during driving individually. Ie. The method according to the invention is used as an engine-specific correction method. In this case, the method corrects or adapts or adjusts internal combustion engine-overlapping, ie, a plurality of internal combustion engine related settings or adjustments of the valve lift adjusting device. Ie. an existing strategy of controlling or regulating the valve lift adjusting device is adapted individually to the internal combustion engine and the circumstances in which the internal combustion engine is operated up-to-date.

Here, the valve lift adjustment is controlled or adjusted in particular for small and / or small strokes. Ie. that the preferably at least partially dethrottled internal combustion engine is idling or an essentially constant and preferably low torque request of a motor vehicle driver is present. The method is preferably carried out at open or at substantially open throttle. However, it is possible to perform the method even with partially closed throttle. In this case, the intake valves act as throttle, d. H. the throttle is more than 50% in particular more than 75% and preferably more than 90% open with respect to their cross-section or maximum air flow rate.

Thus, the internal combustion engine has at least one valve lift adjusting device for at least one valve, the valve lift adjusting device being controlled and / or regulated in such a way that the fuel consumption of this particular internal combustion engine in a given operating point or range is as low as possible or comparatively minimal. This is preferably done with small and / or small strokes of the respective valve (s), in particular of the inlet valve (s). Fuel consumption is preferably a primary criterion of the method. Secondary criteria can, for. B is a smooth running and / or a low vibration of the respective engine concerned.

A primary advantage of the invention is the minimization of the fuel consumption of the internal combustion engine, especially in small and / or small strokes whose valve train, with implicit consideration of manufacturing tolerances and aging effects of the respective internal combustion engine. According to the invention, no cylinder-selective sensor or evaluation functionality, such. B. a cylinder-selective lambda detection or a cylinder-selective engine rotation angle time evaluation, such. As a segment time evaluation or smoother recognition needed. Lambda, smoothness, vibrations o. Ä. Are only indirect variables in terms of the actual goal to set a low-consumption mode of operation of the internal combustion engine. The erfindungemäße method also works when detected malfunction with shutdown of a linear lambda probe, a crankshaft position sensor, a vibration sensor and / or cylinder pressure sensor.

Another advantage is an implicit consideration of a z. B. due to aging of the drive train, for example due to increased crank drive friction, conditional shift of a load or operating point of the engine, the z. B. indicates a higher possible Entdrosselung. Furthermore, the method is not dependent on whether the dynamic properties of a pre-catalyst lambda probe are suitable for a cylinder-specific lambda control. Here are in particular restrictions in a positioning of the linear lambda probe in exhaust gas turbocharger configurations to call what, in particular, systems with not always open to wastegate, such as an overpressure wastegate at low loads concerns.

The method according to the invention can also be carried out before or in particular in time after an adaptation of a fuel metering, in particular an adaptation of injection quantities of one or the fuel injectors. In this case, the adaptation of the injection quantities can be carried out at a substantially maximum stroke or a stroke near the maximum stroke of the relevant or the relevant valves of the internal combustion engine.

The method is preferably carried out online during operation of the relevant internal combustion engine, wherein a controllable by the valve lift adjustment stroke of the valve in question is changed, while other, the fuel consumption of this internal combustion engine influencing control variables are kept constant. The stroke of the valve in question which is changed by the valve lift adjusting device can be used for a subsequent control of the internal combustion engine if it has been recognized that varying the stroke of the valve has led to an improvement in the fuel consumption of the internal combustion engine.

According to the invention, the values for the stroke, which influence the fuel consumption of the internal combustion engine, are varied during the driving operation and the respective, varied values for the further control of the internal combustion engine adopted if an improvement in fuel economy was achieved by the variation. Otherwise, the output values of the manipulated variables that existed prior to the variation can continue to be used for the control. Since the optimization already builds on a solid database, the areas within which the strokes are varied are relatively small, so that the optimization for the motor vehicle driver is barely perceptible. The method can be performed individually for each internal combustion engine over its entire service life. As a result, changes in the internal combustion engine over its entire lifetime can be taken into account.

In embodiments of the invention, the modified stroke of the valve in question can be stored in a control device, if it was recognized that the change in the stroke of the valve in question has led to a deterioration of the fuel consumption of the internal combustion engine. This stored stroke of the relevant valve is then no longer adjusted or adjusted in the short and / or medium term. In the long term, however, this value can again gain in importance if aging effects, for example due to wear and tear, become effective in the internal combustion engine.

The invention will be explained in more detail below with reference to embodiments with reference to the accompanying drawings. In the schematic drawing show:

1 a motor vehicle with an internal combustion engine and a control device for the internal combustion engine;

2 a schematic diagram of a typical gasoline or diesel internal combustion engine;

3 Fresh air filling differences of the cylinders of a four-cylinder internal combustion engine at a small or minimum lift of the intake valves;

4 the fresh air filling differences from the 3 in representation on the lambda hooks of a respective combustion;

5 an embodiment of a method according to the invention, wherein an online optimization of the valve lift adjusting device is shown in the form of a flow chart; and

6 a diagram of a vehicle measurement at idle the internal combustion engine, which represents an interaction of fuel consumption in response to a Entdrosselung.

A motor vehicle 100 of the 1 has an internal combustion engine 1 and a controller 26 (Engine Control Unit, engine control electronics) for the internal combustion engine 1 on. The internal combustion engine 1 is about a powertrain 112 with drive wheels 114 coupled. The control device 26 is via data and signal lines with the internal combustion engine 1 coupled. A motor vehicle driver (not shown) can via an accelerator pedal 111 a torque request to the controller 26 to transfer. The accelerator pedal 111 is an accelerator pedal sensor 113 assigned, which an operating level of the accelerator pedal 111 recorded and sent to the controller 26 transmitted. The greater an amount of accelerator pedal operation by the motor vehicle driver, the greater a requested torque TQI. The control device controls via the data and signal lines 26 the internal combustion engine 1 such that that of the internal combustion engine 1 generated torque TQI corresponds to the torque request of the motor vehicle driver.

The 2 shows a highly simplified embodiment of the internal combustion engine 1 that has at least one cylinder 2 and one in the cylinder 2 reciprocating pistons 3 having. The internal combustion engine 1 further comprises an intake tract 40 , in which downstream of a suction port 4 for sucking in fresh air, an air mass sensor 5 , a throttle 6 , a swirl flap 31 for influencing the suction flow, as well as a suction pipe 7 are arranged. The intake tract 40 flows in one through the cylinder 2 and the piston 3 limited combustion chamber 30 , The fresh air needed for combustion is supplied via the intake system 40 in the combustion chamber 30 initiated, the fresh air supply by opening and closing an inlet valve 8th is controlled.

In the internal combustion engine shown here 1 it is an internal combustion engine 1 with direct fuel injection, in which the fuel required for combustion via a fuel injector 9 directly into the combustion chamber 30 is injected. To trigger the combustion, one also serves in the combustion chamber 30 protruding spark plug 10 , The combustion exhaust gases are via an exhaust valve 11 in an exhaust tract 16 the internal combustion engine 1 discharged and by means of one in the exhaust tract 16 arranged catalytic converter 12 cleaned. In the exhaust tract 16 there is also a controllable exhaust flap 33 ,

A power transmission to the drive train 112 (please refer 1 ) happens via one with the piston 3 coupled crankshaft 13 , The internal combustion engine 1 also has a speed sensor 15 for detecting the rotational speed of the crankshaft 13 and a combustion chamber pressure sensor 32 for detecting the pressure in the combustion chamber 30 , Of the Combustion chamber pressure sensor 32 , which also in the spark plug 8th can be integrated, provides a high-temporal signal, which is the current pressure in the combustion chamber 30 during the intake stroke, the compression stroke, the power stroke and the exhaust stroke.

The intake valves 8th and / or exhaust valves 11 preferably each have a controllable and / or controllable valve lift adjustment 50 , by means of which the valve opening times or the valve strokes can be varied. It is possible, the temporal overlap of the opening periods of the intake valve or valves 8th and the exhaust valve (s) 11 each combustion chamber 30 adjust. This allows both the filling of the combustion chambers 30 be influenced with fresh air or with exhaust gas (internal exhaust gas recirculation) and the gas exchange work. The respective valve lift adjusting device 50 can be realized for example by a hydraulically adjustable camshaft or an electromagnetic valve train.

A single valve lift adjustment device 50 may be one, a plurality or all of the relevant intake valves 8th or exhaust valves 11 influence accordingly. It is preferred that the valve lift adjustment 50 instead of or in addition to the throttle 6 is used to throttle the intake fresh air and one into the combustion chamber 30 incoming air mass or quantity MAF (Mass Air Flow) depending on a requirement of the motor vehicle driver or depending on the operating conditions of the internal combustion engine 1 to meter.

In particular, it is preferred that the valve lift adjusting device 50 to control such that a de-throttled operation of the internal combustion engine 1 is possible, ie the throttle 6 is wide or at most wide open. A slightly closed throttle 6 for an effective tank ventilation (not shown) should be disregarded here. Of course it is also possible the throttle 6 to close to a certain amount and the final throttling of the passing fresh air by means of the valve lift adjustment 50 adjustable inlet valves 8th to leave. However, it is preferred that the intake valves 8th and thus the valve lift adjustment 50 the intake valves 8th the throttle function takes over. Ie. The combustion chambers 30 on the one hand can be filled with fresh air of maximum density, which on the other hand for each operating point of the internal combustion engine 1 can be realized with a respective smallest valve lift.

The internal combustion engine 1 also has a fuel supply system which includes a fuel tank 17 and a preferably arranged therein fuel pump 18 having. The fuel is using the fuel pump 18 via a supply line 19 a pressure accumulator 20 fed. This is a common accumulator 20 , from which the fuel injectors 9 for several cylinders 2 be supplied with pressurized fuel. In the supply line 19 is also a high pressure pump 22 arranged. The high pressure pump 22 Serves through the fuel pump 18 with relatively low pressure (about 3-5 bar) pumped fuel the pressure accumulator 20 supplied with high pressure (typically up to 200 bar at petrol and up to 2,000 bar in diesel engines). At the accumulator 20 is also a pressure sensor 34 to detect the pressure in the accumulator 20 arranged. The accumulator 20 can z. B. be formed in a diesel engine as a common rail.

The internal combustion engine 1 is the controller 26 assigned, which via signal and data lines with preferably all actuators and sensors of the internal combustion engine 1 connected is. In particular, the control device 26 via the data and signal lines with the fuel pump 18 , the air mass sensor 5 , the combustion chamber pressure sensor 32 , the throttle 6 , the swirl flap 31 , the spark plug 10 , the fuel injectors 9 , the / the valve lift adjustment 50 the intake valves 8th and / or the exhaust valves 11 , the exhaust flap 33 , the pressure sensor 34 and the speed sensor 15 coupled. The control device 26 It is therefore possible to vary by transmitting appropriate control signals, all variables and operating parameters, which z. B. torque TQI and efficiency of the internal combustion engine 1 influence.

In the control device 26 Map-based engine control functions (KF1 to KF5) are implemented in the form of software. In particular, in the control device 26 implemented a torque model, which based on the sensor sizes that of the internal combustion engine 1 currently produced torque TQI modeled. By means of the torque model, the actuators and manipulated variables of the internal combustion engine 1 , such as the positions of the throttle 6 , the swirl flap 31 and the exhaust flap 33 , the ignition timing of the spark plugs 10 , as well as the opening periods or strokes of the intake and / or exhaust valves 8th . 11 via the valve lift adjusting devices 50 and the fuel injectors 9 , adjusted such that of the internal combustion engine 1 a given, predetermined torque TQI is produced.

In the normal case, the torque TQI of the internal combustion engine 1 set such that it corresponds to the torque request of the motor vehicle driver. This is in the controller 26 stored a motor-specific database, which, for example, in the form of factored maps and constants in the control device 26 is stored. The database is obtained, for example, by test series on test benches or during test drives. The execution of these test series and test drives, however, takes place on a very limited number of internal combustion engines. Nevertheless, the data obtained is generally used for all internal combustion engines of the respective type. Due to manufacturing tolerances or changes over the lifetime occur on any internal combustion engine 1 individual changes so that the general database with regard to the efficiency, the fuel consumption, the emissions, etc. is not always an optimum or maximum / minimum or local maximum / minimum.

When filling cylinders A, B, C, D (see 3 ) of the internal combustion engine 1 with fresh air arise in particular due to manufacturing tolerances of the valve lift adjustment 50 or the variable valve lift system 50 Especially with small and micro strokes differences in the respective air-fuel mixtures and the respective generated torques of the cylinders A, B, C, D, resulting in a deterioration of the smoothness of the internal combustion engine 1 leads. From Kleinhub one speaks, if the stroke of the Ein- 8th or exhaust valve 11 ≤ approx. 3 mm, the minimum stroke is that in the control device 26 stored according to the invention optimized minimum valve VLFT_MIN, which is usually greater than the minimum possible mechanical valve lift. In 3 the cylinders A, B have a positive and the cylinders C, D a negative tolerance in a valve lift VLFT of the intake valves 8th on.

In the case of the positive tolerance, this leads to an above-average and, with the negative tolerance, to a below-average filling of the respective cylinders A, B; C, D with respect to one of the controller 26 Calculated setpoint of a cylinder filling with fresh air MAF_SOLL. As a result, differences in the fillings of the cylinders A, B, C, D in the case of small and / or minimum stroke are in practice well within ± 10% of the global or average or desired air mass MAF_SOLL.

As a result of the differences in the filling with fresh air, the torques TQI of the cylinders A, B, C, D are formed at different positions of the lambda hooks, which in the 4 is shown. The cylinder-individual lambda differences can in the control device 26 be adjusted again via a "lambda balancing" function. See the arrows in the 4 , Such lambda balancing can result in further increased differences in the cylinder-specific torques, which can result in a further deterioration of smoothness.

In the prior art, this uneven running caused by the different cylinder torques TQI is improved by means of opposite ignition angle interventions. However, this results in turn, depending on the cylinder operating point disadvantages. Is the cylinder, as in the example of 4 the cylinders A, B, by a higher fresh air mass than by the controller 26 Calculated, it will also generate too high a torque TQI, especially if he has already undergone a lambda correction. This excessively high torque TQI is changed by the ignition angle correction in a subsequent combustion with true torque TQI but for higher exhaust gas temperature, lower efficiency and also increased consumption.

These increasing disadvantages are savings in throttle losses due to the operation of the internal combustion engine 1 with small valve lifts VLFT. Even without ignition angle interventions by running smoothness optimization cause filling differences in the small and Kleisthubbereich the intake valves 8th a suboptimal operating point. Ie. that the filling differences due to the manufacturing tolerances at small and small stroke of the intake valves 8th , A fuel-saving potential in the valve lift adjustment 50 limit.

According to the invention, a consumption of fuel as a reference variable for an optimization strategy, especially for small and micro strokes of the intake valves 8th used, wherein the valve lift adjustment 50 is controlled or adjusted accordingly. In addition to low or optimized fuel consumption, there is also a reduction in the emissions of carbon dioxide and possibly an improvement in efficiency. Ie. also that by the optimization strategy according to the invention also a good efficiency of the internal combustion engine 1 is realized at a low or actual as minimal or as fresh as possible comparatively minimal fuel consumption.

According to the invention, fuel consumption is considered to be an essential or major input of control and / or regulation of the valve lift adjustment device 50 used, and not as usual, the comfort criterion quiet running. In a given operating condition of the internal combustion engine 1 an online optimization of a minimum lift VLFT_MIN of the intake valves then preferably takes place 8th in the direction of minimal or minimized or lower or lower or optimized fuel consumption. This is preferably done according to the German patent application with the file number 10 2008 052 323.2 whose content should be included here in full. Corresponding points of contact with this document also emerge from the following remarks. Furthermore, can the invention also to the exhaust valves 11 the internal combustion engine 1 be transmitted.

Implementations within the meaning of the invention are preferably all control and / or regulating mechanisms which have the following characteristics. An input variable is the fuel consumption or a variable that allows a conclusion on the fuel consumption, such. B. an injected or manipulated variable is the stroke VLFT of the valve in question 8th . 11 , An adaptation algorithm controls the VLFT of the valve 8th . 11 in operating points with small and / or smallest air filling to a minimum of the input variable; So the for the valve in question 8th . 11 minimum stroke VLFT_MIN.

In a further development of the invention, in a first adaptation process in a throttled operating state of the internal combustion engine 1 at a maximum stroke VLFT_MAX of the valve or valves 8th . 11 a first adaptation value determined. This adaptation value is based on the consideration that lambda differences in this operating state on tolerances in the fuel metering, in particular due to the fuel injectors 9 , attributed to the fuel metering of the cylinders 2 is adjusted accordingly. With this first adaptation, an adaptation in the manner described above in the direction of minimum fuel consumption is carried out in a second adaptation step in the case of small and minimum lift VLFT_MIN of the valve drive. This can also be reversed according to the invention, that is, first of all an adaptation of the lift VLFT of the valves 8th . 11 and then an adaptation of the fuel metering.

In the 5 is an embodiment of the method as an online optimization of fuel consumption or as an online optimization of a control of the valve lift adjustment 50 , in particular the valve lift adjusting device 50 the intake valves 8th the internal combustion engine 1 during operation of the internal combustion engine 1 in the form of a flow chart. By means of the method according to the invention, the fuel consumption or the control of the valve lift adjusting device 50 an internal combustion engine 1 individually over the entire operating time of the internal combustion engine 1 be optimized or improved.

The procedure is with step 200 For example, after starting the internal combustion engine 1 started. Advantageously, then in one step 201 checks whether the requirements for a minimum or minimum lift of the intake valve (s) 8th exist, so whether the valve lift adjustment 50 corresponding strokes of the inlet valve or valves 8th should realize. This is especially for the idling of the internal combustion engine 1 or even in the case of a low torque request, which is preferably constant over a certain period of time. Further, it is preferable that the internal combustion engine 1 is operated in a substantially de-throttled or only slightly throttled state. This can be done in step 201 an appropriate query will be made. However, it is also possible, the inventive method with a more closed throttle 6 perform.

A substantially constant torque request of the motor vehicle driver can be recognized, for example, when the pedal value of the accelerator pedal 111 of the motor vehicle over a certain period of time is within a predetermined tolerance band. The pedal value of the accelerator pedal 111 , which by the pedal sensor 113 is detected, indicates how far the motor vehicle driver the accelerator pedal 111 has suffered. If the result of the query is negative in step 201 the query is repeated. The method according to the invention is applicable in particular if the following method steps are carried out at idling or an essentially constant torque request of the motor vehicle driver, since this has so far given the best results.

The following explanations only refer to a single inlet valve 8th , However, this may vary depending on the valve lift adjustment 50 to a plurality or all intake valves 8th the internal combustion engine 1 be applied. If the result of the query is positive in step 201 the procedure goes to step 202 in which the lift VLFT_MIN, in particular the small or minimum lift of the intake valve 8th is varied. The remaining control variables of the internal combustion engine 1 , which have an influence on the fuel consumption, are kept constant. The variation of the lift VLFT_MIN of the intake valve 8th For example, it can be done by increasing or decreasing the value (s) by a predetermined amount. This amount of change is preferred to be chosen such that it is neither to component damage nor greater loss of comfort for the motor vehicle driver, z. B. by a sudden change in torque comes.

After the variation of the lift VLFT_MIN of the intake valve 8th in step 202 the procedure goes to step 203 in which it is checked whether due to the new lift VLFT_MIN the intake valve 8th an improvement in the fuel consumption of the internal combustion engine 1 is recognizable. This can be realized, for example, by determining a variable before and after the variation of the manipulated variable, which is a conclusion on the current fuel consumption of the internal combustion engine 1 allowed. The value of the determined value therefore represents a measure of the current fuel consumption of the internal combustion engine 1 Advantageously, this quantity is a specific fuel consumption (amount of fuel consumed per kilowatt hour [g / kWh]).

An amount of fuel supplied and the specific fuel consumption may be determined based on the injection pressure generated by the pressure sensor 34 is detected, and the opening times of the fuel injectors 9 be determined. An improvement in the fuel consumption of the internal combustion engine 1 can be done for example by comparing the size before and after the variation of the manipulated variable. An improvement in the fuel consumption of the internal combustion engine 1 is z. B. detected when the specific fuel consumption, the injected amount of fuel or performed by the engine during the gas exchange work is less than before the variation of the manipulated variable. An improvement of the fuel consumption is also present when the indicated mean pressure or the indicated maximum pressure after the variation of the lift VLFT_MIN of the intake valve 8th is bigger than before.

If the result of the query is positive in step 203 That is, there is an improvement in the fuel consumption of the internal combustion engine 1 by the variation of the lift VLFT_MIN of the intake valve 8th detected, the method goes to step 204 continued by the changed value of the stroke VLFT_MIN stored and for further operation of the internal combustion engine 1 is used.

If the result of the query is negative in step 203 That is, it is after changing the lift VLFT_MIN the intake valve 8th If no improvement in fuel consumption is detected, the procedure goes to step 205 in which the current, changed value of the stroke VLFT_MIN is stored. This value is for the operation of the internal combustion engine 1 and no longer used for further optimization in the short or medium term. In the long term, this value can be z. B. become interesting again due to aging processes. This should be taken into account accordingly.

The procedure then moves to step 206 in which the current, for the operation of the internal combustion engine 1 relevant value of the lift VLFT_MIN of the intake valve 8th is reset to the initial value, ie the last value before the variation of the stroke VLFT_MIN. For further driving or operation of the internal combustion engine 1 therefore, the output value is used.

Following step 204 or step 206 the procedure goes to step 207 in which it is checked whether a predetermined condition for stopping the optimization of the lift VLFT_MIN of the intake valve 8th is satisfied. The condition may be met, for example, if by optimizing the lift VLFT_MIN of the intake valve 8th First, an improvement in fuel consumption and after further variation of the stroke VLFT_MIN a stagnation or deterioration of fuel consumption is detected.

In this case, an optimum or minimum of the lift VLFT_MIN of the intake valve has already been established 8th determined. For example, the condition may be met even if neither decreasing nor increasing the lift VLFT_MIN resulted in improving fuel economy. In this case, the optimal value for the VLFT_MIN stroke was already before the beginning of the variation.

If the result of the query is positive in step 207 ie, the condition for canceling the optimization of the lift VLFT_MIN of the intake valve 8th is satisfied, the process ends in step 208 or continues thereafter, with z. B. can be changed to another manipulated variable to be optimized, since a further variation of the stroke VLFT_MIN the intake valve 8th does not make sense. Ie. Subsequently, a variation of another manipulated variable is started. Such another control variable can, for. B. an indicated mean pressure, an injected fuel amount, an indicated maximum pressure, a position of a combustion center, a performed by the internal combustion engine during a gas exchange work, an ignition timing, a start / end of the fuel injection, an efficiency, a position of the swirl flap 31 and / or a position of an exhaust flap 33 be.

If the result of the query is negative in step 207 in the case that in the previous variation of the lift VLFT_MIN of the intake valve 8th an improvement in fuel consumption has been detected, the direction of the variation, that is, increasing or decreasing the value of the lift VLFT_MIN of the intake valve 8th , and the variation of the same control variable with step 201 continued. In the case that the previously performed variation of the lift VLFT_MIN of the intake valve 8th did not improve fuel economy, the direction of the variation is changed, e.g. B. is caused by an increase in the value of the lift VLFT_MIN of the intake valve 8th to a decrease in the value of the lift VLFT_MIN of the intake valve 8th changed and the variation with step 202 continued.

It should be noted that during the course of the process, the torque request of the motor vehicle driver is constantly monitored. At the moment in which a change in the torque request of the motor vehicle driver is detected, the variation of the lift VLFT_MIN of the intake valve 8th interrupted and the process jumps to step 201 , This ensures that there are no overlaps of the measures performed during the procedure and the normal control of the internal combustion engine 1 comes. According to the invention, this method is also applicable to the exhaust valve (s) 11 analogously applicable.

The 6 shows a plot of a vehicle measurement at idle with an idle speed of about 810 revolutions per minute, wherein an interaction of the fuel consumption in dependence on the Entdrosselung is shown. The fuel consumption drops from approx. 9.5 mg / st (st: stroke, ie single injection) with a valve lift VLFT of 3 mm to approx. 7.5 mg / st with a valve lift VLFT of approx. 0.5 mm, and shows thus clearly an improvement in fuel consumption and efficiency through de-throttling.

As the valve lift VLFT decreases, the degree of dethrottling increases, which is particularly evident at the intake manifold pressure MAP, which is due to the opening of the throttle valve 6 rises to a maximum value of about 940 hPa. At an intake manifold pressure of about 50 hPa below ambient pressure, the Entdrosselung is completed, the fresh air can with maximum density of the cylinder 2 to fill. The degree of delivery and thus the development of the torque TQI is now completely controlled or regulated via the valve train - the so-called unthrottled operation.

The method according to the invention is thus of course also applicable to a method for the individual operation of only one valve lift adjusting device of a respective internal combustion engine. Ie. more generally, that the invention is also applicable to a method for Hubadaption, in particular a Kleinsthubadaption, a variable Ventilhubsystems or a valve lift adjustment.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10156409 A1 [0004]
• DE 10259846 A1 [0004]
• EP 1193381 [0004]
• DE 102008052323 [0042]

Claims (11)

Method for the individual operation of an internal combustion engine ( 1 ) of a single motor vehicle ( 100 ), wherein the internal combustion engine ( 1 ) at least one valve lift adjusting device ( 50 ) for at least one valve ( 8th . 11 ), and the valve lift adjusting device ( 50 ) is controlled / regulated such that a fuel consumption of this internal combustion engine ( 1 ) at a given operating point is as low as possible or comparatively low. Method according to claim 1, wherein the valve lift adjusting device ( 50 ) for small and / or small strokes of the valve ( 8th . 11 ) according to the criterion of the lowest possible or comparatively low fuel consumption of this internal combustion engine ( 1 ) is controlled / regulated. A method according to claim 1 or 2, wherein the method in an Enthrottled or a substantially throttled, or a slightly to moderately throttled state of an intake tract ( 40 ) of this internal combustion engine ( 1 ) is carried out. Method according to one of claims 1 to 3, wherein the fuel consumption of this internal combustion engine ( 1 ) is a primary criterion of the method, and a secondary criterion of the method preferably a smooth running and / or a low vibration of this internal combustion engine ( 1 ). Method according to one of claims 1 to 4, wherein the method temporally before or preferably in time after an adaptation of a fuel metering, in particular an adaptation of injection quantities of a fuel injector ( 9 ), wherein the adaptation of the injection quantities preferably takes place at a substantially maximum lift (VLFT_MAX) of the valve (FIG. 8th . 11 ) of the internal combustion engine ( 1 ) is carried out. Method according to one of claims 1 to 5, wherein the method during an operation of this internal combustion engine ( 1 ) is performed, and a through the valve lift adjustment ( 50 ) adjustable lift (VLFT) of the valve (VLFT) 8th . 11 ), while others, the fuel consumption of this internal combustion engine ( 1 ) influencing manipulated variables are kept constant. Method according to one of claims 1 to 6, wherein the by the valve lift adjusting device ( 50 ) varied stroke (VLFT) of the valve ( 8th . 11 ) for a temporally following control of the internal combustion engine ( 1 ), if it is detected that the change in the lift (VLFT) of the valve ( 8th . 11 ) to improve the fuel consumption of the internal combustion engine ( 1 ) has led. Method according to one of claims 1 to 7, wherein the method is carried out when the internal combustion engine ( 1 ) is idling or a substantially constant and preferably low torque request of a motor vehicle driver is detected. Method according to one of claims 1 to 8, wherein the changed stroke (VLFT) of the valve (VLFT) 8th . 11 ) in a control device ( 26 ) is stored if it is detected that the change in the stroke (VLFT) of the valve ( 8th . 11 ) to a deterioration of the fuel consumption of the internal combustion engine ( 1 ) and this stored lift (VLFT) of the valve (FIG. 8th . 11 ) will be discontinued in the short and / or medium term. Method according to one of claims 1 to 9, wherein the method is used as an internal combustion engine-individual correction method, which engine-wide settings or Einregelungen the valve lift adjusting device ( 50 ) corrected or adapted. Control device for an internal combustion engine ( 1 ) of a motor vehicle ( 100 ), which is designed such that by the control device ( 26 ) a method according to any one of claims 1 to 10 is feasible and / or carried out.

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