KR100768360B1 - Method and device for operating an engine - Google Patents

Abstract

An engine operating method and apparatus are proposed. When switching from one operating mode to another, the amount of fuel injected and the set ignition angle are calculated in one switching step, in part, in accordance with the previous and new operating modes.

Engine, cylinder, mode of operation, homogeneous operation, stratified operation, ignition angle, switching stage, fuel level, mixer, microcomputer.

Description

METHOD AND DEVICE FOR ENGINE {METHOD AND DEVICE FOR OPERATING AN ENGINE}

1 is a basic block diagram of a fuel direct type engine control apparatus.

2 is a flowchart of a program for executing a transition state from homogeneous operation to homogeneous lean operation.

3-8 are block diagrams illustrating the transition from one operating mode to another for homogeneous, homogeneous lean and stratified modes of operation.

<Detailed Description of Main Parts of Drawing>

10: control unit

12: input circuit

14: microcomputer

16: output circuit

18: communication system

20, 24: input line

22, 26, 42 to 46: measuring device

36 to 40: input line

48 to 52: output line

54: injection valve

The present invention relates to a method and apparatus for operating an engine, in particular a gasoline direct type engine.

The gasoline direct-dial engine is operated in at least two modes and the operating mode is switched in accordance with at least one enabling signal. Modes of operation include, in particular, homogeneous lean operation, stratified operation and homogeneous operation. This type of operations can be cited, for example, in German patent 198 50 587. According to the disclosure, a control unit for switching each operation mode is provided. This conversion is done via an intermediate step. A series of actions are performed to switch from one mode of operation to another within the scope of the intermediate stage.

German Patent No. 197 28 112 describes a control system for a gasoline direct-dial engine based on moment. In order to control the engine in the homogeneous operation of the throttled state, a target moment value representing a moment that is actually statically adjusted is preset, as is known in conventional control systems. The moment value is adjusted through the air path, and the amount of fuel injected is determined according to a predetermined air-fuel ratio (general theoretical ratio). In addition, for the crankshaft synchronization path, an additional target moment value, which is set via ignition angle adjustment, is preset, which path contains, for example, the dynamic moment requirement of the idle controller. The target moment for the ignition angle is adjusted by changing the ignition angle while taking into account the actual parameters of the engine. Preferably in other modes of operation with lean mixers, such as stratified operation and / or homogeneous lean operation, the target value normally adjusted via the first path does not work because the engine continues to run in a non-axle state. to be. Here, the target moment value for the crankshaft synchronization path including the static component is realized through the amount of fuel injected. If the switching conditions between the two operating modes are given, the target moment determination is correspondingly changed, which also applies to the calculation of the ignition angle. In homogeneous operation, the ignition angle change can be provided similarly in homogeneous operation according to the target moment and the actual moment, while in stratified operation, the ignition angle in the stratified operation does not carry out the change in which the moment is changed as described above and is read out from the characteristic area. do.

Since the transition from one operating mode to another is done via an intermediate step rather than a rapid change mode, parallel calculation of the ignition angle and fuel output is possible when switching from one operating mode to another. In the scope of the control system described in DE 197 28 112, the transition is described as follows.

In German patent 198 50 581 a method for measuring the actual torque of a gasoline direct injection engine is known. In the publication one moment model is used, in which the parameters of the moment are adapted according to the current operating mode to determine the actual moment of the engine on the basis of the same model.

According to the invention, the target moment for the crankshaft synchronization path is reliably provided. The target moment also corresponds to the operating mode assigned to each cylinder during the switching process. This further optimizes the conversion process.

In the new applied mode of operation, in which the target moment associated with the fuel supply is calculated, at least when switching from homogeneous or homogeneous lean operation to another operating mode, the two cylinders still filled with fuel are ignited by the fuel already charged. The target moment for the ignition angle effective for the preceding operating mode is provided for the cylinders. For the ignition, if one target moment can be presented for the current operating mode already provided, the wrong ignition angle is output and an undefined actual moment may occur. As a result, the torque behavior becomes undesirable during the conversion process. This is effectively prevented by the output of the target moment for the special situation during the transition.

In contrast, in the case of stratified operation switching, the redundant calculation and output of the target moment in the new operating mode already applied must be made from the stratified operation for the new and previous operating modes. This improves the transition. The calculation of the target moment for fuel and / or the output of the moment in switching to stratified operation is delayed to allow for pre-use storage of fuel in the previous mode of operation.

Another advantage is presented in the following description from the embodiment or the dependent claims.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. 1 shows a control unit 10. The control unit comprises at least one input circuit 12, at least one microcomputer 14, an output circuit 16 and a communication system 18 connecting the output circuits as elements. Input lines are supplied to the input circuit 12 through which signals are transmitted from corresponding measuring devices. The signals represent or derive operating parameters. For example, the input line 20 connects the control unit with the measuring device 22 which determines the parameter shown in the actuation ß of the accelerator pedal, the input line 24 starting from the measuring device 26 and This line is supplied with one variable representing the engine rotation speed Nmot. The input line 28 connects the control unit 10 with the measuring device 30 which outputs a signal indicative of the amount of air HFM supplied. In addition, input lines 36 to 40 are provided which transmit other signals from the measuring devices 42 to 46 representing operating variables. Examples of this type of operating variable used in engine operation include temperature variables, throttle valve positions, exhaust gas components, and the like. From the embodiment of the output circuit 16 shown in FIG. 1 to control the engine, the output lines 48 to 52 for controlling the injection valve 54 and the throttle valve 58 adjustable with an electric motor One output line 56 is provided. Ignition is also initiated (not shown for reasons of individuality).

Moment demands (target moments) are formed for engine control, and various internal and / or external moment requests are integrated into the engine to form the final moment demands. An example of such a request is a request by the driver, i.e. an external system such as a drive slip control device. The switching of the moment demands is made different depending on the operating mode of each selected engine. The resulting target moment in homogeneous operation is divided into a slowly reacting charge path and a fast acting crankshaft synchronization path, with the charge path being the main path and controlling the static rotational moment. The target fill amount controlled via throttle valve control is calculated from the target moment. In the crankshaft synchronization path, a predetermined moment is dynamically adjusted by the influence of the ignition timing and fuel control by the fade-out of each cylinder. At this time, in the crankshaft synchronization path, the target moment is coupled to the calculated actual moment and the deviation is minimized by adjusting the setting parameters for the ignition angle and / or fade-out.

Similarly in stratified operation, the target moments generated are divided into target moment values applied in the slowly reacting charging path and target moment values applied in the fast acting crankshaft synchronization path. At this time, the crankshaft synchronization path serves as the main path. Since the throttle valve should be opened as wide as possible for reasons of moment loss, the target filling and consequent adjustment of the throttle valve in stratified operation is not carried out according to the target moment value but rather according to the minimum necessary intake vacuum. Here, the target moment value for the crankshaft synchronization path is converted by determining the amount of fuel to be injected.

The above also applies to other modes of operation which are operated non-axially, for example homogeneous lean operation.

For example, output signals of additional functions such as idle adjustment are converted to target moments for the crankshaft synchronization path (fuel path), at least in non-axle operation.

The difference between the modes of operation lies in the calculation of the ignition angle and the calculation of the actual moment. In homogeneous operation and homogeneous lean operation, the target moment is switched through the ignition angle according to the actual moment calculated for the ignition angle to be output. Here, the actual moment is calculated, for example, by the first mentioned model for the data processing applied to each operating mode for the ignition angle.

When switching from one operating mode to another, in the intake phase (homogeneous, homogeneous lean), in order to calculate in parallel the target moment for fuel in the new operating mode and the target moment for the ignition angle in the previous operating mode A) is achieved by preliminary storage of the injected fuel. In order to achieve optimized combustion and thus a desired moment during the conversion process, it is necessary to initiate parallel calculations through the fuel supply of the target moment and fuel supply via the ignition angle in various modes of operation. This points to an important purpose in the provision of the target moment corresponding to the suitable mode of operation described below. In the new mode of operation, the two cylinders filled with fuel must be ignited in the previous mode of operation, so that the target moments considered in the previous mode of operation are output to this cylinder.

When switching from stratified operation (meaning stratified catalytic heating and homogeneous stratified operation) to another operating mode, parallel calculation of target moments and parallel outputs for multiple cylinders in both operating modes for charging of fuel in the new operating mode While initiated for fuel injection, the transition to stratified operation takes place in the previous mode of operation over a period of time (typically synchronization = 180 degrees crankshaft angle) until the target moment output is achieved.

The flow chart of FIG. 2 shows the transition state in one example of the transition from homogeneous operation (HOM) to homogeneous lean operation (HMM). The program is executed in synchronization with the crankshaft and begins with the application of a homogeneous lean operation. In step 100, the counter Z is set to a value of zero. In step 102 the target moment MSOLLK for the fuel path in the homogeneous lean operation is calculated and provided for the determination of the target fuel amount. Then, in step 104 the target moment MSOLLZWHOM is calculated as before through the ignition angle of the previous homogeneous operation, and the actual moment MISTHOM for the homogeneous operation is determined correspondingly in the next step 106. In step 108 the ignition angle is determined and provided in accordance with the actual moment and the target moment measured in the homogeneous operation. In step 110 the counter Z is raised to 1 and in step 112 it is queried whether the counter has reached the value K. If not, the program proceeds freshly for the next synchronization point using step 102. If the counter number does not reach the value (K), it is converted to homogeneous lean in the moment calculation of the operating mode. The switching state shown in FIG. 2 ends. In other words, when switching from homogeneous operation to homogeneous lean operation, the ignition angle K is output in the previous homogeneous operation mode, and the correct fuel injection of the new homogeneous lean operation mode is achieved. As shown in Fig. 2, the target moment is calculated correspondingly so that the target moment for the fuel supply and the target moment for the ignition angle for the homogeneous lean operating mode are determined in accordance with the provision of the homogeneous operating mode. Ignition angle control is performed correspondingly upon provision of homogeneous operation. This is not adapted for the fuel supply since the fuel supply is switched directly by the operating mode. This method results in a transition from homogeneous operation to homogeneous lean operation. For four-cylinder cylinders, the constant K is generated as two.

Corresponding programs are provided for the transition states from and to stratified operation. This switching method is described below with reference to the time chart in which the program is derived.

The transition from homogeneous operation to homogeneous lean operation is shown in the time chart of FIG. 3, and the transition from homogeneous lean operation to homogeneous operation is shown in FIG. 4.

The state in which the time T is applied from left to right in a four-cylinder engine is shown. The spray (unfilled rectangle), closing time (filled rectangle) and ignition point (flame shape) are shown.

Figure 3 shows the homogeneous mode of operation (B_HOM), the homogeneous lean mode of operation (B_HMM) and the state of the transition phase (B_HOMHMM), the state of ignition angle calculation (B_MDZWHMM) according to the calculation criteria of the homogeneous lean operation, For example, the state B_BRKMDZW when not generated in stratified operation is shown. First, the system is in homogeneous operation (status bit (B_HOM) setting). Fuel is injected into the first cylinder before the synchronization default value (0, time point t0). Fuel is injected into the second cylinder according to the homogeneous operation between the time points t0 and t1. At time t1, the homogeneous lean operation is applied, and the homogeneous operation is terminated (bits B-HOM are reset and bits B-HMM are set). The operating mode is also switched. Therefore, the transition state is introduced from the time point t1 to the time point t3 (status bit B_HOMHMM setting). Since the cylinder injected just before the time point t0 between the time points t1 and t2 is ignited, the closing time and ignition time point for the first cylinder is determined according to the homogeneous operating mode. Between the time points t1 and t2, the fuel amount for the third cylinder is preferably formed and output corresponding to the method for the homogeneous lean operation mode. Between the time points t2 and t3, the mixer present in the second cylinder is ignited by a predetermined ignition angle calculated corresponding to the method of homogeneous operation. In other words, the output of the target moment for the ignition angle adjustment and the ignition angle calculation are achieved according to the methods provided for the first two cylinders in homogeneous operation. Further, between the time points t2 and t3, the target moment for the fourth cylinder, based on the amount of fuel to be injected and this variable, is calculated and output corresponding to the method of homogeneous lean operation. At the time point t3 the conversion process is terminated and the target moment calculations and ignition angle calculations are calculated corresponding to the methods provided in the homogeneous lean operation (see status bit B_MDZWHMM). Thus, the ignition angle is output according to the homogeneous lean operation between the time point t3 and the time point t4 for the third cylinder. In the first cylinder, the fuel set in the homogeneous lean operation is injected between the time points t3 and t4, and in the fourth cylinder the mixer is set to correspond to this operating mode between the time points t4 and t5. Is burned according to the angle.

The above also applies to the transition from homogeneous lean operation to homogeneous operation (compare FIG. 4). Also in the above transition, as shown in Fig. 3, the transition request is set at the time t1 (status bit B_HMM reset, bit B_HOM setting), so that the transition state is achieved between the time t1 and the time t3. (Figure 4, Status Bit (B_HMMHOM) Comparison). The determination of the ignition angle according to the target moment of the homogeneous operation and the calculation criteria for the homogeneous operation are executed at the corresponding status bit transition time t3. In addition, an ignition angle for the amount of fuel injected and calculated for the homogeneous lean operation (for the first and second cylinders) is provided between the time point t1 and the time point t3, the ignition angle being likewise for the current operating mode. Is calculated (decision according to homogeneous method at time t3, reset status bit B_MDZWHMM). At the same time fuel is injected into the third and fourth cylinders in the time step, the fuel having already been determined according to the method of calculating homogeneous operation. The fuel is ignited at a predetermined ignition angle between a time point t3 and a time point t4 to a time point t4 and a time point t5, and the ignition angle is a method of homogeneous operation based on a target moment and an ignition angle calculation method. It depends on.

At the time of switching to stratified operation, for example from homogeneous to stratified operation, or when switching from homogeneous lean operation to stratified operation, two ignition angles are provided for the previous homogeneous to homogeneous lean operating modes. Fuel injection for the new stratified mode of operation takes place immediately after switching. Also in the injection, it should be ensured that the previous operating mode is taken into account in the ignition angle in the determination and reset of the target moment. This consideration is taken into account when parallel calculations of the target moment, actual moment and ignition angle are initiated during the corresponding operating phase.

5 shows the transition from stratified operation to homogeneous operation as a time plot. As can be seen from the status bit, at time t1 it is switched from homogeneous operation to stratified operation (resetting of bit B_HOM, setting of bit B_SCHH). A transition step is initiated between time point t1 and time point t3 (B_HOMZWSCH activation). Fuel injection for the second and third cylinders is achieved before time t1 in accordance with the calculation method induced by the air in homogeneous operation. Therefore, the ignition angle is calculated according to the ignition angle moment setpoint and calculation method of homogeneous operation for the second and third cylinders during the switching step. The fuel supply to the third cylinder is first determined at the end of the switching stage at time t3 because no storage before use of fuel occurs in stratified operation. The calculation of the fuel quantity is based on the target moment value for the fuel path. The mixer in the cylinder is ignited at a predetermined ignition angle in the same time section, and the ignition angle is determined corresponding to the characteristic area adjustment for stratified operation (setting the bit B_BRKMDZW from time point t3). The fuel injection for the first cylinder at time t4 is correspondingly executed in accordance with the stratification operation, and the ignition angle calculation of the characteristic region is correspondingly executed. Therefore, after the end of the first switching step (resetting B_HOMZWSCH), the ignition angle calculation is switched, but the switching for fuel amount determination is already started at time t1. Notably, in homogeneous operation, injection following storage of fuel before use is abandoned for a given time section.

The above applies to the transition from homogeneous lean operation to stratified operation, which is shown in FIG. Further, in the transition, the transition is initiated at time t1 (compare status bits B_HMM, B_ZWSCH), and one transition step for the transition is made up to time t3 (bit B_HMMZWSCH is set). The ignition angle for the second and third cylinders whose fuel calculation is achieved according to the target moment in the fuel path of the homogeneous lean operation is calculated based on the calculation of the target moment and the homogeneous lean operation for setting the ignition angle for the cylinder. On the other hand, in the fourth cylinder, it is injected with a predetermined amount of fuel, which is calculated according to the target moment for the fuel path in stratified operation and is first delayed to the time point t3. Since the switching of the ignition angle calculation (resetting B_MDZWHMM, comparing the setting of B_BRKMDZW) occurs at time point t3, the fourth cylinder, the first cylinder and the other cylinders are ignited according to the characteristic area ignition angle of the stratified operation.

In the conversion from stratified operation to homogeneous operation or homogeneous lean operation, shown in Figs. 7 and 8, the fuel amount calculation in conversion between the operation modes is achieved in parallel for two cylinders in each operation mode.

In Fig. 7, first, at the time t0 and the time t1, the first and second cylinders supply the amount of fuel calculated according to the target moment of stratification operation. At time t1, a request to switch from stratified operation to homogeneous operation is achieved (B_SCH reset, B_HOM setting). A transition step follows between the time points t1 and t3 (set in B_ZWSCHOM), in which the amount of fuel calculated according to the method of homogeneous operation is supplied to the fourth and first cylinders. That is, it is adapted to the induction method by air. On the other hand, fuel is supplied to the third cylinder also at the time point t2, and the fuel amount is calculated according to the target moment for the fuel path in parallel with the determination of the fuel amount for the fourth cylinder, and then ignited by the characteristic region angle. In addition, in the step of switching between the time points t1 and t2, the target moment for the fuel according to the stratification operation is calculated in parallel with the fuel amount determination adapted to the air setting. Switching of the ignition angle calculation is achieved at time t1, and the last ignition angle for the mixer ignition is frozen in the second and third cylinders. Correspondingly, the same applies to the fuel amount in one embodiment. The ignition angle for the fourth cylinder injected in the homogeneous operation at the time point t3 is calculated and output according to the target value for the ignition angle path in the homogeneous operation.

This also applies to the conversion of stratified operation to homogeneous lean operation as shown in FIG. The transition is achieved at time t1 (B_HMM setting, B_SCH reset), and the transition state lasts until time t3 (B_ZWSCHHMM setting), in which the transition step actually involves a method in stratified operation and a method in homogeneous operation. Thus, where the second and third cylinders, injection is achieved in parallel. The ignition angle determination is achieved with the ignition after the time point t3 according to the homogeneous operation, while the third cylinder filled with the fuel amount of the stratified operation is ignited according to the frozen ignition angle for the stratified operation.

All of the points mentioned above are taken into account when standardizing the actual moment for conversion. During the transition from lean mode of operation (stratified operation, homogeneous lean) to the other mode of operation, the amount of fuel provided last is saved because the transition is taken into account in two ignitions of the next new mode of operation (based on the amount of fuel injected) Determination of the actual moment). Similarly, in the new mode of operation the normalized moment is calculated as a function of the ignition and fuel volume of the previous mode of operation.

According to the present invention, the target moment for the crankshaft synchronization path is reliably provided, thereby providing the effect of optimizing the switching process between operating modes.

Claims (10)

delete delete Operating in at least two operating modes, switching between both operating modes, determining at least the amount of fuel injected and the set ignition angle for each operating mode, and operating from one operating mode to another A method of operating an engine comprising the step of providing a transition step when transitioning to a mode, During the switching of the operating modes, when the amount of fuel injected or the set ignition angle for each cylinder is determined, the previous operating mode and the current operating mode are considered, Modes of operation include stratified, homogeneous or homogeneous lean operation, While the fuel amount is adapted to the air supply, in stratified operation, the target moment for execution is preset by the amount of fuel injected, while in homogeneous lean operation, the target moment for execution is preset by the amount of fuel injected and by the ignition angle. , In homogeneous operation, the target moment for execution through the ignition angle is preset. 4. A method according to claim 3, wherein the ignition angle is set according to the characteristic region in the stratified operation, and the ignition angle is set according to the actual moment and the target moment in the homogeneous lean operation or the homogeneous operation. 4. The method of claim 3, wherein the amount of fuel injected into the cylinder to be injected after initiation of the conversion step, when switching from homogeneous lean operation to homogeneous lean operation or in transition from homogeneous lean operation to a new operating mode. A method of operating an engine, characterized in that the setting of the ignition angle for a cylinder not yet ignited takes into account the previous operating mode. 4. The method according to claim 3, wherein the amount of fuel injected for the next actuated cylinder in the transition step from stratified operation to homogeneous operation or from stratified operation to homogeneous lean operation is taken into account, and In parallel, while the amount of fuel injected for the cylinder ignited after the charging period is determined in consideration of the new operating mode, the assigned ignition angle is determined in consideration of the corresponding operating mode. The ignition angle for an already filled cylinder is determined in consideration of the previous mode of operation, according to claim 3, wherein during switching from homogeneous operation to stratified operation or from homogeneous lean operation to stratified operation, while the operating mode is switched, The amount of fuel injected into the cylinder to be ignited thereafter is determined in consideration of the new operating mode, and the engine is characterized in that the first injection for the new operating mode is delayed by not charging while the operating mode is switched. How it works. Operating in at least two modes of operation, having a control unit to switch between the two modes of operation and to determine at least the amount of fuel injected and the set ignition angle for each mode of operation, from one mode of operation to another An engine operating device provided with a switching step when switching to During the switching of the operating modes, when determining the amount of fuel injected or the set ignition angle for each cylinder, the previous operating mode and the current operating mode are considered, Modes of operation include stratified, homogeneous or homogeneous lean operation, While the fuel amount is adapted to the air supply, in stratified operation, the target moment for execution is preset by the amount of fuel injected, while in homogeneous lean operation, the target moment for execution is preset by the amount of fuel injected and by the ignition angle. , In homogeneous operation, the target moment for execution via the ignition angle is preset. A computer readable data storage medium having stored therein a computer program having program code means for carrying out all the steps of claim 3 when the program is run on a computer. delete

Images