JP2012163095A - Method and device for adapting drive state of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of responding to temporary or continuous change of a drive condition.SOLUTION: The present invention relates to a method for changing a drive state of an internal combustion engine. With at least one sensor, data characteristic to the drive state of the internal combustion engine is detected and transferred to a control device. With the control device, an optimum drive region of the internal combustion engine is determined on the basis of the data, and at least for a determinant engine drive parameter for a combustion process, a necessary setting value for maintaining or reaching to the optimum drive region is determined, and an actual value of the engine drive parameter is controlled to the setting value, so that the drive state of the internal combustion engine is intentionally adapted to the optimum drive region.

Description

  The present invention relates to a method for changing the driving state of an internal combustion engine according to claim 1. The invention further relates to the use of the method according to claim 9, the device according to claim 10 for carrying out the method and the control device therefor according to claim 11.

  The use of the internal combustion engine is preferably carried out in an optimum driving range adjusted for the intended use of the engine. A typical optimum driving range is distinguished by, for example, that fuel consumption during driving is minimized. The drive state of the internal combustion engine is therefore preferably kept in this optimum drive region. However, the combustion quality of the fuel / air mixture used, and thus the driving conditions, is kept consistent and constant, such as fuel composition, intake air temperature, fuel quality, residual gas content in the cylinder, etc. Depends on a number of drive conditions that cannot be achieved.

  Therefore, the optimum drive region may be left during engine operation. If the optimum driving range is left, undesirable phenomena such as engine knocking sometimes occur. Under such a premise, there is known a method capable of recognizing that the optimum drive region has been left. It is important to stop knocking as quickly as possible to avoid engine damage. Therefore, at the time of driving a known internal combustion engine, for example, a knock control method and an anti-knock device as disclosed in Patent Document 1 are used.

  When knocking occurs, according to the described method, the ignition angle is retarded to the anti-knocking region and, immediately thereafter, at least one measure from the catalog to stop knocking at the original driving point. Is introduced. If it is determined that a measure does not achieve the desired purpose and knocking at the original drive point continues, the measure is deleted from the catalog and the subsequent alternative measures from the catalog are tested. The purpose of the known method is to restore the original driving state and further operate the internal combustion engine without knocking phenomenon.

  The driving state of the internal combustion engine is changed temporarily according to a known method, an attempt is made to eliminate the cause of knocking, and if the method is successful, it is restored to its original driving state. . This method has the disadvantage that persistent changes in driving conditions are not taken into account. Therefore, it can be considered that knocking is not successfully stopped in the original driving state and the described method does not lead to results. Recovery of the original driving state is not possible under changed driving conditions. The engine must therefore be further operated or switched off while knocking or in some cases in a non-optimal driving range.

German Patent Application Publication No. 10360022

  It is therefore an object of the present invention to provide a method that can react to temporary or persistent changes in drive conditions. An internal combustion engine so driven should operate optimally even if the driving conditions are continuously changing and the original driving state cannot be restored. In addition, a device determined to carry out the method and a control device suitable for it will be provided.

  The present invention solves this problem with respect to a method having the features of claim 1. The use of the method and the apparatus for carrying out the method are described in independent claims 9 and 10, and the control device is listed in claim 11. Advantageous configurations are set forth in the further claims.

  According to the method of the present invention, the driving state of the internal combustion engine is changed using at least one sensor and a control device, and for this purpose, data characteristic of the driving state of the internal combustion engine is detected by the sensor, and these It is proposed to transfer the data to the control device, to determine the optimum drive region of the internal combustion engine by the control device based on the data and to adapt the drive state to the optimum drive region. The controller determines at least the set values necessary to maintain or reach the optimum drive range for the engine drive parameters that are decisive for the combustion process, and the actual values of the engine drive parameters are set to the set values. This adaptation is done by being controlled.

  If the engine drive parameters (eg, ignition timing, combustion air ratio, ignition duration, air mass flow) continue to be the same, one or more drive conditions can be determined if it is determined that a sudden change in engine combustion has occurred. It can be inferred that the (eg fuel composition) has changed. However, if the drive conditions change, it can be inferred that the optimum drive range for the engine drive parameters considered is also displaced, i.e., for example, the fuel composition has changed.

  In accordance with the proposed invention, the control device calculates a new optimal drive range, for example taking into account a known engine characteristic map calculated for example with different standard fuels or adjusted to different drive conditions. . If the internal combustion engine still operates in the optimal drive range, the controller will maintain the current optimal drive range. If the optimal drive region for the engine drive parameter to be considered is left, the engine drive parameter optimized for the new optimal drive region is calculated and the current engine drive parameter, which is the actual value, is set The value is updated to a new optimum engine drive parameter.

  For example, an engine control device is used as the control device. In some cases, the engine control device may be supplemented with corresponding functionality on the basis of the available engine control device, so that it can be implemented at low cost and with add-ons.

  The controller calculates a setpoint for at least one engine drive parameter that is decisive for the combustion process, in order to translate the behavior method described above. According to the present invention, the set value is determined when the currently determined drive state is already in the optimum drive region, the optimum drive region is maintained, and the current drive state is not in the optimum drive region. By controlling the actual value of the drive parameter to the set value, the drive state is selected so as to be led directly or gradually to the optimum drive region. The advantage is that by adapting the engine drive parameters, the area of use in which the internal combustion engine can be driven optimally is expanded. Continuously adapting engine drive parameters to continuously changing drive conditions could only be performed by manual operation according to the prior art.

  According to a preferred embodiment, a knock value or a numerical value depending on the knock value is calculated as data. For this purpose, a knock sensor, for example a piezoelectric vibration sensor according to the field, for example with an integrator for amplifying signals, is used. Often already existing sensors may be used to perform the claimed method. The method can be implemented in an inexpensive manner for use with available internal combustion engines. Therefore, for example, when knocking is confirmed, this is used as a trigger for changing the driving state. The method according to the invention can supplement or replace the method for knock control implemented in the engine control device.

  A further possibility is to use a pressure sensor for detecting the ignition pressure value, for example. The data characteristic of the engine operating state in this case includes the ignition pressure value, ie the measured actual value (instantaneous recording) of the rapidly changing ignition pressure, the numerical value depending on it, or the entire course of the ignition pressure. In addition to pressure sensors, other sensors may also be used and the method can be adapted to sensors available in cooperation with special internal combustion engines.

  The driving state of the internal combustion engine can be determined based on one or more numerical values. Useful values include engine speed, rotational moment value, ignition pressure value, intermediate pressure occupying the ignition process, combustion air ratio λ, ignition time t, ignition duration, ignition pressure elapsed, ignition energy, spark combustion duration, Temperature. In this way, the method can be adapted to various engines, and the driving conditions are determined, for example, such that already existing sensors are used.

  The optimum driving range of the engine, which depends on the respective driving conditions, for example the fuel composition, is adapted to the reference values resulting from the intended use of the internal combustion engine. As an optimal driving region, for example, an efficiency region is set in advance depending on driving conditions. For each drive condition, there is a drive point where, for example, fuel consumption is minimal. A drive area where the fuel consumption is close enough to a given minimum can in this case be preset as an efficiency area. An optimal drive area is preset for each drive condition. A further example is to define the efficiency region by the emission value when driving must be within a given interval. In order to calculate the optimum drive range, experience data such as, for example, an engine characteristic map, among others, may be cited.

  According to the invention, the engine drive parameters that are decisive for the combustion process are at least one of the combustion air ratio λ, the ignition time t, the engine speed, the rotational moment, the ignition energy, the spark combustion duration and / or these engine drive parameters. A numerical value depending on one can be used. Which engine drive parameters are used may be adjusted to the determined internal combustion engine and / or the specific usage of the internal combustion engine.

  For at least one engine drive parameter, the control device presets a set value. The set value may be limited to a given value region if necessary. In order to protect the engine from unacceptable adjustments or to comply with emission regulations, a limited range of values is reasonable because the determined engine drive parameters, for example the ignition time t, should be within defined boundaries. Can be An unacceptable adjustment may be, for example, a premature ignition point that will certainly cause knocking combustion. Emission regulations play a special role, for example, in stationary large gas engines used for industrial purposes.

  According to a preferred embodiment of the invention, a given value interval for the set value to be determined is determined depending on the driving state of the internal combustion engine. In the determined driving state, it may be reasonable to allow a large value interval, while for other driving states a smaller value interval is suitable. If a large value interval is allowed for the set value, the actual value can be changed in large increments (difference between the set value and the current actual value). This is especially reasonable when knocking is confirmed. Then the internal combustion engine should operate in the danger zone and the driving state should be changed instantly. A noteworthy numerical value in this connection is, for example, the ignition timing. Once the engine begins to knock, the interval for a given set point of ignition time can be chosen large, and the ignition time is immediately established at a much slower value. This increases the change increment. If the engine leaves the danger zone and a new setpoint is established, a fine adjustment may begin, so a much smaller increment can be selected to change the ignition timing, which is gradually and slowly It can be changed in a faster direction. In this second stage of control, a small value interval for the set value is preset, and the actual value of the engine drive parameter is controlled to a series of set values in multiple steps gradually.

  If it is determined that the internal combustion engine drive condition is already within the optimal drive range adapted to the current drive conditions, the setpoint cannot be changed very slightly or at all, and the interval is chosen very small. The In this way, the control process is optimized. Moreover, this also optimizes the efficiency of the internal combustion engine and prevents increased wear or other risks.

  In order to determine the engine drive parameters, in particular the set point of the ignition time t and / or the combustion air ratio λ, an engine characteristic map may be referenced. Such engine characteristic maps depend in particular on fuel parameters. Therefore, the engine characteristic map can be calculated with various standard fuels. For this, for example, contractually guaranteed fuels may also be used. That is, engine characteristic maps calculated with different fuels having different compositions can be used. When the driving state changes, the set value can be quickly found by various engine characteristic maps, and can be gradually controlled to one set value or a series of set values. In this way, a targeted adaptation of the drive state is made and each known experience data can be considered together. Close control based on accurate knowledge of each internal combustion engine is important, not trial and error testing of the measures in turn.

  The method can also be applied to various internal combustion engines, in particular gas engines or more specifically gas otto engines. In the case of a gas engine, it is a common phenomenon that the composition of the combustion gas used changes over time. With the method according to the invention, the optimum driving range of the engine can be adjusted dynamically for each gas composition.

  In order to carry out the method, an apparatus comprising a sensor and a control device is preferably used. The sensor calculates data characteristic of the driving state of the internal combustion engine, and transfers this data to the control device. Depending on the data, the control device always calculates the optimal driving range of the internal combustion engine, at least for maintaining or reaching the optimal driving range for engine driving parameters that are critical to the combustion process. Necessary set values are determined and the actual values of the engine drive parameters are controlled to the set values.

  In particular, the control device according to the present invention uses an appropriate algorithm for calculating an optimum driving range from data characteristic of the driving state of the internal combustion engine transmitted by the sensor. In addition, this algorithm determines at least the set values necessary to maintain or reach the optimum drive range for engine drive parameters that are decisive for the combustion process, and to determine the actual values of engine drive parameters. A signal used to control the output is output. This algorithm can account for a wide variety of characteristic variables of the combustion process, depending on the embodiment, and can use all given empirical data. Preferably, the algorithm utilizes various engine characteristic maps that may be adjusted, for example, to different fuels or different fuel compositions.

  The invention is explained in more detail below by way of example with reference to the accompanying drawings. The following is shown in the figure.

1 is a schematic block diagram of an embodiment of a method according to the present invention for changing the driving state of an internal combustion engine. FIG. It is a figure of various drive states and drive regions of an internal combustion engine. It is a figure of various drive states and drive regions of an internal combustion engine. It is a figure of various drive states and drive regions of an internal combustion engine. It is a figure of various drive states and drive regions of an internal combustion engine. 1 is a block diagram of an embodiment of an apparatus for changing a driving state of an internal combustion engine.

  FIG. 1 shows, in conjunction with FIG. 3, a block diagram of a method and apparatus for controlling the driving state of an internal combustion engine according to an embodiment of the present invention. The sensor 2 detects data in the first step S1, and based on the data, a control process is performed by the engine control device 1 in the course of subsequent steps, as will be explained in more detail below.

  In the illustrated embodiment, the apparatus comprises an engine control device 1 and a plurality of sensors 2. From the data transmitted by the sensor 2, the engine control device 1 calculates the driving state (Z1) and the optimal driving range (W) of the engine, controls the given engine driving parameters, and thereby the driving state (Z1). ) Remains in the optimum driving region (W) or is led to the optimum driving region (Wn).

  The internal combustion engine not shown in detail is, in the embodiment shown, a fixedly driven gas otto engine. The sensor 2, in the embodiment shown, is a knock sensor 3 in the form of a piezoelectric vibration sensor with an integrator, an engine speed sensor 4 and a pressure sensor used to measure the ignition pressure value. 5 and a rotational moment sensor 6.

  The knock sensor calculates data characteristic of the engine drive state (Z1). In this case, a knock value is detected as the data. Data calculated by the sensor 2 is transmitted to the engine control device 1 through the data connection unit 7. The algorithm 8 calculates the current driving state (Z1) of the gas engine from the data transmitted from the engine control device 1.

  The current driving state Z1 of the gas engine is represented as a point (Z1) in FIG. 2a. The two coordinate axes of the represented graph symbolize various numerical values that characterize the driving state of the gas engine, such as engine speed, engine speed, combustion air ratio λ, ignition timing, ignition duration, etc. ing.

  The algorithm 8 of the engine control device 1 shown in FIG. 3 further calculates an optimal drive region W that depends on the data transmitted by the sensor 2. This drive area is represented in FIG. 2a as a circular area with finely drawn parallel lines. In this drive region W, the gas engine operates optimally. In this case, the optimum driving area W is a sufficiently small area surrounding the optimum driving point. In the present case, this region can be understood to have minimal fuel consumption in this region. FIG. 2a thereby represents the desired driving situation, the engine driving parameters of the gas engine, which are important for the optimal driving range W, being correctly adapted by the engine control device and the driving state Z1 thus achieved. Are within the optimum drive region W.

  FIG. 1 schematically represents a method for changing the driving state. The detection of the sensor signal just described is represented as step S1 in FIG. Calculation of the current drive state Z1 and the optimum drive region W is performed as step S2. In the next step S3, the algorithm 8 of the engine control device 1 calculates whether or not the drive state Z1 is in the optimum drive region W. If this is the case as shown in FIG. 2a, is the driving state Z1 maintained by the engine control device 1 holding the engine driving parameters constant or only slightly adjusting it? Or, only slightly, it is modified in the sense of fine tuning and the method starts the same process again. This is represented as a return from step S3 to step S1.

  In order to carry out the described method, the engine control device 1 uses, in the illustrated embodiment, the ignition time t and the combustion air ratio λ as engine drive parameters. In the case just described, that is, when the driving state is in the optimum driving range, the engine control device 1 keeps the set values for the ignition time t and the combustion air ratio λ unchanged. The control of these two parameters is represented by the data / control lines 9 and 10 in FIG. 3, and the directions of the two arrows symbolize that the control is performed. When performed and represented by a component or machine component 11, a device 12 for measuring and changing the ignition time t and an exhaust gas measuring device 13 or a device for determining the combustion air ratio λ Done in

  However, if the algorithm 8 determines that the driving state Z1 of the gas engine is outside the optimal driving range W, the driving state Z1 must be changed and adapted accordingly. In the embodiment shown, two engine drive parameters that are decisive for combustion are used to change the drive conditions, on the one hand the ignition time t and on the other hand the combustion air ratio lambda. Control is performed by adjusting the set values for the ignition time t and the combustion air ratio λ.

  To illustrate the embodiment shown, we start from the premise that the gas composition of the combustion gas used has changed, so that the ignition time t and the combustion air ratio λ are no longer suitable for optimal combustion. The change in the combustion gas relates to, for example, the proportion of hydrocarbon or inert gas. Changes in this component or its proportion in the gas affect the number of methane, the burning rate, the calorific value, and the like. The optimum drive region W has been adjusted to the former gas composition, while the new gas composition requires the optimum drive region Wn (Wn is “new W”). The initial situation in this case is represented in FIG. The drive state Z1 is outside the optimum drive region Wn.

  For additional illustration, consider that the gas engine has begun knocking. As shown in FIG. 2b, this causes drive state Z1 to now enter a drive zone K, which is a danger zone, that is, a zone where the engine is knocked. As shown in FIG. 1, the method does not return from step S3 to step S1, but proceeds to step S4, where algorithm 8 sets another setting for ignition time t and combustion air ratio λ. The value is confirmed. For this purpose, an engine characteristic map representing empirical data, in particular the optimum ignition timing and combustion air ratio, for example, depending on the speed and the ignition pressure is referred to and used in the algorithm 8. .

  When determining a new set value in step S4, the algorithm 8 controls whether the set value remains in a given value interval. This prevents unacceptable adjustments from being made, for example, using a mixture that is too thick which can result in a drive that is too high in emissions. Moreover, the given value interval at which these setpoints must be present depends on the current driving state Z1 of the gas engine. In the case shown (see FIG. 2b), Z1 is in the knocking region K and a large increment should be achieved when changing the setpoint, i.e. the ignition time t and the combustion air ratio λ, so that the value interval is Therefore, it is largely selected.

  By controlling the actual values of the ignition time t and the combustion air ratio λ to the set values, a new drive state Z2 is quickly achieved. This is illustrated in FIG. The driving state Z2 is now outside the knocking region K, but not yet in the optimum driving region Wn. In the control step, the engine drive parameters and thus the drive state are changed significantly. A large value interval for the set value was calculated, thereby achieving a large change increment.

  Within the framework of the control process just described, in step S5 of the method, it is controlled whether the actual values for the two engine drive parameters correspond to the set values. If so, the process immediately returns to step S3 to control whether or not the drive state Z2 is in the new optimum drive region Wn. If so, the process returns to step S1. The method starts from the beginning. Even in the situation represented in FIG. 2c, if Z2 is not in the new optimum drive region Wn, the method again reaches step S4. The set value is newly adjusted.

  Since the engine is no longer in the knocking region, the value interval for the set values of the two engine drive parameters used in the illustrated embodiment is selected to be smaller. The subsequent control process is a fine adjustment of the engine drive parameters. Unlike the adjustment by large increments, the first purpose of the fine adjustment is not to change the driving state from an undesired driving condition to a desired driving condition as quickly as possible in order to avoid danger, but to optimize driving range Wn. Is achieved accurately and directly. For this purpose, a small value interval for the set value is preset, whereby a small change increment is achieved. Therefore, a series of set values is determined, and the actual values of the engine drive parameters are gradually controlled to the set values. After each setpoint is achieved, the next setpoint may be determined anew or for the first time. In this way, the driving state of the gas engine is gradually led to the state Z3. The target state of this gradual process is represented in FIG. 2d, and the driving state Z3 is again in the optimum driving region Wn.

  The gas engine can now operate further and there is no reason to attempt to restore the original drive state Z1.

  The optimum drive area was finally displaced following the change in gas composition. The former drive region W was optimal for the previous gas composition, but the drive region Wn is optimal for the new gas composition. The described method takes this change into account and always optimizes the engine drive depending on the dynamically changing drive conditions.

DESCRIPTION OF SYMBOLS 1 Engine control apparatus, control apparatus 2 Sensor 3 Knock sensor 4 Engine speed sensor 5 Pressure sensor 6 Rotation moment sensor 7 Data connection part 8 Algorithm 9 Data and control line 10 Data and control 11 Engine component or machine component 12 Ignition time For measuring and changing gas 13 Exhaust gas measuring device

Claims (11)

In a method for changing the driving state of an internal combustion engine,
Data characteristic of the driving state (Z1) of the internal combustion engine is detected by at least one sensor (2) and transferred to the control device (1), and the internal combustion engine is based on the data by the control device (1). The settings required to maintain or reach the optimum drive range (W) when the optimum drive range (W) of the engine is determined and at least for engine drive parameters that are decisive for the combustion process A value is determined and the actual value of the engine drive parameter is controlled to the set value so that the drive state (Z1) of the internal combustion engine is adapted to the optimum drive region (W). .   The method according to claim 1, wherein the knock value, the ignition pressure value, the progress of the ignition pressure and / or a numerical value depending on them are detected as data.   The driving state (Z1) of the internal combustion engine includes a rotational speed, a rotational moment, an intermediate pressure, a combustion air ratio λ, an ignition time t, an elapsed ignition pressure, an ignition energy, a spark combustion duration, or a numerical value depending on them. The method according to claim 1, wherein the method is determined based on at least one numerical value selected from the following.   4. The method according to claim 1, wherein an efficiency region depending on the data is determined as the optimum driving region (W).   2. A set value for at least one engine drive parameter, in particular a combustion air ratio λ, an ignition timing t, an engine speed, a rotational moment, an ignition energy and a spark combustion duration, is determined. Item 5. The method according to any one of Items 4.   6. The method according to claim 1, wherein the set value of the engine drive parameter is determined within a given value interval.   Method according to claim 6, characterized in that the given value interval is selected depending on the current driving state (Z1).   8. The set point for the ignition time t and / or the combustion air ratio λ is determined taking into account a predetermined engine characteristic map which depends in particular on the fuel parameters. The method according to any one of the above.   Use of the method according to any one of claims 1 to 8 for controlling the operating state of a gas otto engine. At least one sensor (2) for detecting data characteristic of the driving state (Z1) of the internal combustion engine;
The optimum drive range (W) depending on the data is determined, and at least the settings necessary to maintain or reach the optimal drive range (W) for engine drive parameters that are critical to the combustion process 10. A device for carrying out the method according to any one of claims 1 to 9, characterized in that the control device (1) determines the value and controls the actual value to the set value.   A control device (1) for changing the driving state of an internal combustion engine depending on data characteristic of the driving state, wherein the control device (1) determines an optimal driving region (W). Determining at least one setpoint required to maintain or reach the optimum drive range (W) of the engine drive parameter that is decisive for the combustion process, and to set the actual value of the engine drive parameter to the set value A control device (1) for outputting a signal for control.