JPH04140450A - Apparatus for controlling and/or adjust- ing fuel preparation value and/or igni- tion angle for internal-combution engine - Google Patents

Abstract

PURPOSE: To rapidly detect a shift to a dynamic operation by transferring a measured value when the actually measured value at present time upon dynamic operation of an internal combustion engine is different from a preceding measured value or a counting process reaches its maximum value. CONSTITUTION: When, for instance, the value of the pressure of an intake pipe required for a control or an adjustment is determined, the content of a counter is first increased by one 10, every time a measurement is carried out. After that, it is examined 11 whether or not the counted value of the counter reaches the number of cylinders of an internal combustion engine. When a reply is YES, the counter is reset to zero. Then, the value PL of a load at the present time, that is, the instantaneous value of the pressure of the intake pipe is read to compare it with the preceding value PL-1 of the load. If PL<=PL-1 , the value PL-1 is used for a control or an adjustment. On the contrary, if PL>PL-1 , the value PL is used for a control or an adjustment. At this time, the counters are simultaneously reset to zero 17. Then, a new program process is started.

Description

[Detailed description of the invention]

[0001]

[Industrial application field]

The present invention provides fuel control for an internal combustion engine in which the load is detected by measuring the instantaneous value of a periodically changing measured quantity using a sensor once for each ignition in synchronization with the crank angle. The present invention relates to a device for controlling and/or adjusting quantity and/or ignition angle. [0002]

[Prior art]

Some of the operating parameters normally detected by sensors in internal combustion engines, such as the intake pipe pressure, the intake air volume, or the rotational speed of one of the rotating shafts of the internal combustion engine, are more or less continuous values; This value changes during the operating cycle of the internal combustion engine [0003] For controlling internal combustion engines, where there are no high demands on the accuracy or practical responsiveness of the measured values, it is necessary to An average value can be used to determine periodic changes. However, in order to precisely control modern internal combustion engines, for example in order to determine the fuel metering or the optimum position of the ignition angle variation, the operating parameters must be determined on the one hand as precisely as possible and on the other hand as quickly as possible. There is a need to. Although the formation of an average value from a plurality of previous measurements is accurate, it provides measured values so far in advance that they cannot be used for precise control of the internal combustion engine. [0004] According to Federal Republic of Germany Patent No. 3223328,
Measuring devices for detecting periodically changing operating parameters of internal combustion engines are known. With this device, the measurement of the aforementioned values, e.g. the pressure in the intake pipe of an internal combustion engine, is carried out once every ignition interval, synchronized with the ignition, and the current measured actual value at a given crankshaft position is are recorded, and the average value of the values is calculated from these measured values. However, due to the different operating performance of the individual cylinders, the magnitude of the periodically changing operating parameters in question is different, which leads to undesirable fluctuations in the measured values, for example in steady-state operation of an internal combustion engine.
This may lead to inaccurate determination of the fuel supply amount or to jumps in the ignition angle. [0005]

[Advantages of the invention]

In contrast, the device according to the invention having the features described in the characterizing part of claim 1 has the following advantages. This means that under any operating conditions, periodically changing operating parameters can be detected very precisely, and load changes, i.e. transitions from steady-state to dynamic operation in the internal combustion engine, can be detected very quickly. This is guaranteed. [0006] This high degree of accuracy in measurement value detection is achieved as follows. That is, parameters that change periodically in steady state are measured once for each ignition in synchronization with the crankshaft, but for the control and/or adjustment of fuel metering and/or ignition angle, the crankshaft is This is achieved by using this parameter only once for each rotation. For this reason, the same measured values are always used for the control or regulation of the internal combustion engine, independent of the operating performance of the individual cylinders. The operating parameters which vary in the internal combustion engine are likewise determined synchronously with the crankshaft once for each ignition, but in this case the respective constant values are not used for controlling or regulating the fuel metering or the ignition angle of the internal combustion engine. Therefore, in the case of dynamic conditions, it is not possible to compensate for the differences caused by differences in the operating performance of the individual cylinders;
This is not required. This is because changes caused by changes in load are significantly larger. However, in the case of dynamic operation, the values used for control or regulation are instead very immediate. The invention is illustrated in the drawings and is explained in detail in the following description. [0008]

【Example】

FIG. 1 shows the pressure in the intake pipe of an internal combustion engine with respect to the crank angle of an eight-cylinder engine during steady-state operation, as an example of a measured value that varies periodically during the operating cycle of the internal combustion engine. At that time, the intake pipe pressure PL is shown in millibar, and the crank angle is the rotation speed t of the crankshaft.
/U. Furthermore, the firing order of the individual cylinders is entered. The characteristic curve of the intake pipe pressure is shown at a rotation speed of 5.250 revolutions/min with respect to the crankshaft. It can be seen from FIG. 1 that the instantaneous value of the intake pipe pressure P fluctuates around a constant average value during the operating cycle of the internal combustion engine. For an 8 cylinder engine running in steady state operation, the cycle duration will be 90° crank angle. The magnitude of the maximum pressure value or the magnitude of the minimum pressure value depends on the operating performance of the individual cylinder, the structure of the intake pipe and the pressure measurement position. With respect to the position of the crankshaft, if the pressure is always detected at the same position, for example the position indicated by In this case, an accurate value is obtained that is independent of changes in the intake pipe pressure and the different operating performance of the individual cylinders. As described in the description of FIG. 2, if the pressure is determined at position X, as shown in FIG. 1, a transfer of the measured value takes place at position y. [0009] In the case of dynamic operation, that is, when the load is increasing or decreasing, the periodic fluctuation components of the intake pipe pressure are superimposed on the overall increase or decrease of the intake pressure; , pressure detection as in the case of steady-state operation is not possible in the dynamic state, since the resulting component is higher than the vibration in steady-state operation. [0010] According to the invention, the intake manifold pressure is constantly increased, i.e., during steady-state and dynamic operation, synchronously with the crankshaft, once for each ignition, that is, for every 90° crank angle for an 8-cylinder engine, the pressure It is detected by a sensor and guided to an evaluation circuit. In the evaluation circuit each measured value is compared with the previous measured value. At the same time, a counter provided in the evaluation circuit is started. This counter then counts up to the number of cylinders, eg up to 8 in the case of an 8-cylinder engine. The contents of the counter are incremented by one each time a measurement is recorded. [0011] The combination of the content of the counter and the instantaneous value of the intake pipe pressure provides a value of the intake pipe pressure that can be used for controlling and/or regulating the fuel metering and/or ignition angle of the internal combustion engine. , whereby the transition from steady-state operation to dynamic operation can be quickly detected. The detailed flow of the evaluation process is clarified by the flowcharts shown in FIGS. 2 to 4. In this case, one evaluation example is shown for each flowchart. [0012] FIG. 2 shows a first embodiment for determining the value of the intake pipe pressure required for control or regulation. At that time, the program in the computing device shown in the flowchart is
The operation is completed once for each ignition in synchronization with the crankshaft. In a first step 10, the contents of the counter are incremented by one each time a measurement is taken. In the next step 11, it is checked whether the number counted by the counter has reached the number of cylinders of the internal combustion engine. If the current number in the counter is equal to the number of cylinders, the counter is reset to zero in step 12 and the computing device then Step 13 Hejjump. [0013] In step 13, the current load value, that is, the instantaneous value of the intake pipe pressure, is read, and in step 14, it is compared with the previous load value PL-1. In this case, the value of the preceding load P
, -1 is the previous value of the intake pipe pressure used for control or adjustment. In other words, this is not necessarily the value immediately before the instantaneous value of the intake pipe pressure, but is only a value during dynamic operation. [0014] If the current load value PL is smaller than the preceding load value PL-1, it is checked in the next step 15 whether the counter has counted up to the number of cylinders of the internal combustion engine. If the number of cylinders has not been counted, the current load value P is ignored and the previous load value PL-1 is used for control or adjustment. On the contrary,
In step 14, if the current load value P is greater than the previous load value PL-1, or if the counter has counted up to the number of cylinders, the program jumps to step 16. In step 16, the current load value is transferred for control or adjustment. At the same time, the counter is reset to zero in step 17. A new programming process is then started. Such a method of detecting the intake pipe pressure ensures that: In other words, in a steady state, that is, if the load does not change, the maximum pressure in the intake pipe is always detected during two revolutions of the crankshaft, and this can be used for control or adjustment, while all other It is guaranteed that the measured value will again be ignored. In other words, in the case of FIG. 1, which shows a steady state, the values marked with symbols are always used. On the other hand, in a dynamic state, each measured value is used for control or adjustment if the intake pipe pressure increases. This is because each instantaneous value of pressure is greater than the previous value. If the load is reduced, in this method as well, the maximum pressure in the intake pipe is always used for control or regulation. [0015] Another flowchart is shown in FIG. In the case of FIG. 3, the control or regulation takes place with the respective minimum sensor signal during two revolutions of the engine. In this case, the principle flow is the same, but the comparison with the previous intake pipe pressure results in a reduction in the intake pipe pressure value and a transfer for control or regulation. In other words, the difference from FIG. 2 is limited to step 14, that is, the comparison between the current load value P and the previous load value P,-1, and in this embodiment, PL <(PL-1'' If so, the transfer is performed. [0016] A third embodiment is shown in FIG. 4. In the case of FIG. 4, the average value of the intake pipe pressure is calculated in synchronization with ignition. In this case, the value used for control or adjustment is 1/2 of the sum, that is, the average value of the load values determined according to Figs. 2 and 3, that is, 1/2 [(P) + (P) ' ] = P
L(MW)L-I L-1 is used. [0017]

【Effect of the invention】

The device according to the invention makes it possible to detect periodically varying operating parameters under any operating conditions with great precision and to detect load changes, i.e. transitions from steady-state to dynamic operation of the internal combustion engine, very quickly. can be detected.

[Brief explanation of the drawing]

FIG. 1 shows the course of a measured value, for example an intake manifold pressure, which changes periodically in the operating cycle of an internal combustion engine as a function of the crank angle; FIG. 2 is a flowchart diagram showing an embodiment for detecting the instantaneous value of a measured quantity that changes periodically during two rotations of the crankshaft.

FIG. 3 is a flow chart diagram showing an embodiment for detecting an instantaneous value of a measured quantity that changes periodically during two revolutions of the crankshaft.

FIG. 4 is a flowchart diagram showing an embodiment for detecting an instantaneous value of a measured quantity that changes periodically during two rotations of the crankshaft.

[Documentary] Drawings

[Figure 1]

[Figure 2]

[Figure 4]

Claims (8)

[Claims] Claims: 1. A fuel control system for an internal combustion engine, wherein the load is detected by measuring the instantaneous value of a periodically changing measured quantity using a sensor, once for each ignition, in synchronization with the crank angle. In devices for controlling and/or adjusting the quantity and/or the ignition angle, the current measured actual value is compared with the previous measured value in an evaluation circuit and the coefficient content of the counting device is determined after each measurement. A counting process is started in which the maximum value is counted up to a value corresponding to the number of cylinders of the internal combustion engine, such that the current measured actual value is equal to the previous measured value during dynamic operation of the internal combustion engine. transmission of measured values takes place only if they differ with respect to the selectable characteristic, or only if the counting process reaches its maximum value during steady-state operation of the internal combustion engine. Device for controlling and/or regulating fuel metering and/or ignition angle of an internal combustion engine, characterized in that: 2. The transfer of the measured value takes place if the current measured actual value is greater than the previous measured value or if the counting process has reached its maximum value.
The device described. 3. Device according to claim 1, characterized in that the transfer of the measured value takes place if the current measured value is smaller than the previous measured value or if the counting process reaches its maximum value. 4. An average value is formed from the two measured values formed according to claim 2 and claim 3,
A device according to claim 1. 5. During steady-state engine operation, instantaneous value measurements are made once for each ignition, but only one measured value is transferred during two revolutions of the crankshaft,
Apparatus according to any one of claims 1 to 4. 6. During steady-state engine operation, salient points in the course of the periodically varying measured quantities, such as maximum or minimum values, are used to determine the measured values to be transferred. 6. The device according to claim 5. 7. The device as claimed in claim 1, wherein during the dynamic state the quantity to be detected is measured once for each ignition and each measured value is transferred. 8. According to claim 1, the counting process is always reset in a particular cylinder during the cylinder detection provided, so that the particular cylinder is used for the transfer of measured values. equipment.