DE69935639T2 - A fuel injection control apparatus and method for an internal combustion engine - Google Patents

Description

The The present invention relates to an apparatus and a method for controlling fuel injection into an internal combustion engine, More specifically, an apparatus and method for controlling the Fuel injection into an internal combustion engine, with which torsional vibrations an output shaft system of the internal combustion engine can be prevented can.

torsional vibrations an output shaft of an internal combustion engine, for example occur in a vehicle engine, cause fluctuations (for example Shocks that while the acceleration or deceleration occur, pressure phenomena o. Ä.) In the acceleration of Vehicle if accelerated or decelerated, or jumps if the vehicle is in a steady running state. Therefore the driving behavior of the vehicle deteriorates. Especially becomes the required fuel injection quantity for a diesel engine dependent on set by an operating condition of the engine (for example the engine speed and the degree of depression (opening degree) of an accelerator pedal). Therefore, the required amount of fuel injection varies immediately with the opening degree the accelerator pedal.

If injected a required amount of fuel injection into the engine is changed The torque generated by the engine quickly, resulting in increased torsional vibrations of the output shaft system leads. To prevent this, a so-called smoothing control is performed on the diesel engine when the required amount of fuel injection increases rapidly when For example, an acceleration is performed. In the case mentioned above will be the actual Fuel injection amount gently to the required fuel injection amount elevated.

on the other hand is a method known with the torsional vibrations of a wave system indeed be detected to the output torque of the internal combustion engine to control so that torsional vibrations can be prevented. A control device in the above-mentioned method Application is found for example in the Japanese Patent Application 60-26142.

A Device of the above type detects any State size, like for example, the size of the fluctuation the speed of the diesel engine, the magnitude of the fluctuation of the acceleration a vehicle in the longitudinal direction, in the engine of the vehicle is mounted, and the size of the fluctuation the torsional moment of the output shaft of the motor. A detected State variable finds as a vibration size use, the represents the torsional vibrations. Dependent on from the value of the detected magnitude of the torsional vibrations will be the actual Fuel injection quantity of the engine so regulated that torsional vibrations be prevented.

The However, a device of the above type has a limit in terms of elevating the fuel injection amount at a rapid acceleration. It There is therefore the possibility that the acceleration behavior deteriorates.

As explained above, detects every conventional one Device a surge size as one Value that the actual Torsional vibrations, like the speed of the motor, affect the acceleration of the vehicle in the longitudinal direction and the torsional moment of the output shaft of the motor. The fuel injection amount becomes dependent on the size of the torsional vibrations regulated. As explained above, becomes the size of the torsional vibrations using the speed of the motor, the acceleration of the Vehicle in the longitudinal direction and the torsional moment of the output shaft of the motor calculated. However, the factors mentioned above may occur during the Speeding up the vehicle will vary rapidly, even if no Torsionsvibrationen be generated. If the detected value of Size of the fluctuation, like the speed of the engine, the acceleration of the vehicle in the longitudinal direction and the torsional moment of the output shaft of the motor for controlling the torsional vibration is used, for example, a change the speed of the engine coinciding with the acceleration of the vehicle goes along with unwanted Way detected as an increase in torsional vibrations. Im above mentioned Case, the fuel injection amount is corrected to the fluctuation to suppress. Therefore, the required increase in the fuel injection amount be limited, so that the acceleration behavior of the engine deteriorates becomes.

The EP 0655554 A1 describes a method for correcting surges in a fuel injection internal combustion engine of a type having an electronic engine management system that uses the values of the engine based on given strategies and based on values derived from the characteristic parameters of operation of the engine Control parameters are determined, which control the operation of the engine, wherein at least one control parameter is corrected in response to fluctuations in the engine torque. In this method, the following steps are used: estimating the instantaneous value of the fluctuations in the motor torque by filtering the speed of the drive shaft; Determine the Correction to be made with the control parameter by applying a variable multiplication gain at the instantaneous value of the fluctuations in the torque, characterized in that the step of estimating the instantaneous value of the fluctuations in the engine torque comprises the steps of: calculating the average speed by filtering the current speed ; Calculating the difference between the current speed and the average speed; Calculating the mean difference between the current speed and the average speed by filtering the difference between the current speed and the average speed; Calculating the difference between the mean difference between the current speed and the average speed on the one hand and the difference between the current speed and the average speed on the other.

The US 5,669,354 A describes a torque control of an internal combustion engine to dampen undesirable engine speed variations, wherein the changes are measured as high frequency engine speed variations at a known engine operating angle and for each combustion event in the cylinder where the change is present, a phase compensated desired torque variation is calculated to estimate the engine speed change by projecting the engine speed variation phase at the known engine operating angle to damp phase to the next combustion event and to calculate the output torque variation of an opposite cylinder to dampen the engine speed change phase at that next combustion event. The torque change is then performed via a change in the ignition timing in the combustion event or by a change in the amount of fuel supplied for ignition in the combustion event.

It is the object of the present invention, a method and a Device for controlling the fuel injection in an internal combustion engine to create a satisfactory effect with respect to the prevention of torsional vibrations can be achieved without to deteriorate the acceleration characteristics of the internal combustion engine.

This The object is achieved by the combination of the features of independent claims 1 and 5 achieved while the dependents claims further advantageous embodiments disclose the invention.

To the Achievement of the above object is achieved according to a Aspect of the present invention, an apparatus for controlling the fuel injection provided in an internal combustion engine, the vibration detection devices for Detecting a state variable, the the amplitude of the torsional vibrations of an output shaft system the internal combustion engine, as Torsionsvibrationsparameter and a fuel injection amount correcting means for correcting a fuel injection amount of the internal combustion engine comprises Torsional vibrations in accordance with to prevent the detected torsional vibration parameter, wherein the fuel injection amount correcting means change in the torsional vibration parameter that has occurred to date is stored as a hysteresis value and wherein a vibration component extraction means is provided to detect a Torsionsvibrationskomponente from the Torsional vibration parameters using the hysteresis value to extract, the fuel injection amount depending on the size of the torsional vibration component is corrected.

According to the above aspect, the vibration parameter is detected with respect to the amplitude of the torsional vibrations. The hysteresis value of the torsional vibration parameter is used to extract only the torsional vibration component representing the torsional vibrations of the shaft system from the detected torsional vibration parameter. The torsional vibration parameter may be, for example, the rate of change of engine revolutions, forward acceleration (in the longitudinal direction), torsional torque of an engine output shaft, or the like. For example, the hysteresis value of the torsional vibration parameter may be the magnitude of the torsional vibration parameter value within a predetermined past period. Accompanied by the increase in engine revolutions, forward acceleration, and the torsion torque of the shaft during acceleration of the engine, the parameter value of the torsional vibrations increases. The torsional vibrations can add the resulting torsional vibration parameter value to the increased parameter of the torsional vibrations during acceleration. The slope value of the motor revolutions, the forward acceleration, or the torsion torque of the shaft is not significantly changed. In other words, the slope value of the parameter of vibrations during acceleration is substantially constant. The parameter value of the vibrations due to the torsional vibrations usually takes either a positive or a negative value. Thus, only the component related to the torsional vibrations can be extracted from the torsional vibration parameter by measuring the magnitude of the torsional vibrations within a predetermined past period and the magnitude of the instantaneous torsion onsvibrationsparameters be compared.

A Correction of the fuel injection quantity as a function of the magnitude of the torsional vibration component make it possible, to correct the fuel injection amount so that torsional vibrations be prevented without for the Acceleration required fuel quantity to limit. Therefore, you can Torsionsvibrationen be prevented without being a disadvantage Influence on the engine acceleration is exercised.

at In the above aspect, it is effective that the vibration component extracting means stores a value obtained by smoothing the change of the torsional vibration parameter was obtained, which occurred to date as a hysteresis value is, and that the vibration component extraction means a Sets value by subtracting the hysteresis value from a change value the instantaneous torsional vibration parameter as the instantaneous torsional vibration component was obtained.

If the change value the engine revolutions is used as a vibration parameter, he will by combining the change acceleration, deceleration o. Ä., the a relatively long change cycle owns, and the change in the torsional vibrations with a relatively short cycle of change receive. Therefore, in the above-mentioned embodiment, the fluctuation of Engine revolutions via smoothed a given period of time, to calculate a value from which the variations of the change value the revolutions due to the torsional vibrations are. The calculated value is used as the hysteresis value.

Therefore represents the hysteresis value the change value of turns during acceleration or deceleration, the independent of Torsionswert is. When the hysteresis value from the current torsional vibration parameter value is subtracted, only the vibration component of the torsional vibration parameter be extracted exactly. The change value the engine revolutions can be smoothed be determined by the arithmetic mean of the change value of the revolutions within a given period or one described later Process derived value is used.

It is effective that according to the above-mentioned aspect the vibration component extraction device contributes the torsional vibration component extracted a predetermined time interval and the fuel injection amount correcting means Vibration correction amount of the fuel injection amount according to the extracted Torsionsvibrationskomponente calculated and the vibration correction amount halved to a fuel injection amount that is in accordance with a Operating condition of the engine is set to the fuel injection amount to correct and reduce the absolute value of the vibration correction amount, if an inverse pattern of sign inversions of the torsional vibration component matches a given pattern.

If in the embodiment described above, the timing pattern the sign inversions of the extracted torsional vibration component to a predetermined pattern, can be a commuting to the nominal value while of the control process can be prevented by the absolute value of the Vibration correction amount is lowered.

The Engine revolutions, the acceleration of the vehicle and the torsional moment The output shaft is likely to produce a very small degree to vibrations resulting from the change of the Output torque from the cylinders of the engine and the influence a mechanical element (for example, a transmission) of Output shaft of the engine results. The of the vibration component extraction device Extracted vibration component contains the aforementioned changes. Therefore, if the above-mentioned change cycle coincides with the cycle for controlling to prevent the torsional vibrations is while the controller generates a pendulum effect. As a result, fluctuations can occur be amplified in the inverse of the sign of the vibration correction quantity, which leads to a divergence of the control. This oscillation can be prevented be by the control gain provisionally is set to a low value. By adjusting the Regelvestärkung to a small value, however, the response of the scheme to Preventing the torsional vibrations are delayed, so that no satisfactory Effect with respect to preventing vibration is achieved. Therefore, in the present invention, the timing pattern of sign inversions the torsional vibration component, which causes the commuting, preliminarily stored. If the actual timing pattern coincides with the stored pattern, the vibration correction amount is lowered (i.e. H. the control gain decreased). As a result, the control gain is only reduced if the opportunity a commute exists. If there is no commuting, the reinforcement not reduced. Therefore, with the embodiment described above a satisfactory effect for suppressing vibration in one Prevention of commuting achieved.

Lowering the Vibration Correction Size In the case of the possibility of hunting, not only the partial lowering of the vibration correction amount but also the setting of the vibration correction amount to zero (ie, the interruption of the fuel injection correction).

These Summary of the invention does not describe all necessary Characteristics, so that the invention also described in a sub-combination of these Features can be found.

It Now follows a brief description of the drawings. Hereof show:

1 a schematic representation of the construction of an embodiment in which the present invention is applied to a diesel engine for a vehicle application;

the 2A and 2 B Charts showing changes in engine revolutions during acceleration, respectively;

3 a flowchart of a process for preventing torsional vibrations;

4 a flowchart of a process for setting a fuel injection amount;

5 a flowchart of a process for preventing oscillation; and

6 a map used to determine the occurrence of a rocking.

A embodiment The present invention will now be described in conjunction with the drawings explained.

1 FIG. 12 is a schematic diagram of an embodiment in which the present invention is applied to a diesel engine for a vehicle. As 1 shows is a diesel engine 1 (In this embodiment, a four-cylinder four-stroke engine) on a vehicle 10 assembled. drive wheels 9 are from an output shaft (not shown) of the engine 1 powered by a gear unit 3 via a drive shaft 5 , a differential 7 and axes 8th communicates. A shaft system that waves from a crankshaft of the engine 1 up to the drive wheels 9 is hereinafter referred to as the "output shaft system for the engine 1 " designated.

An electronic control unit (ECU) 30 for controlling the engine 1 is designed as a microcomputer having a RAM (Random Access Memory), a ROM (Read Only Memory), a CPU (which is a microprocessor) and inputs / outputs. In this embodiment, the ECU performs 30 a basic control, for example, a regulation of the fuel injection of the engine 1 and a correction of a fuel injection amount for preventing torsional vibration, which will be described later.

The ECU 30 for carrying out the above-mentioned regulations has an input, with which an accelerator opening sensor 31 via an AD converter (not shown). In addition, a crankshaft sensor 35 with the input of the ECU 30 connected.

The accelerator opening sensor 31 is adjacent to an accelerator pedal (not shown) of the engine 1 arranged to generate a voltage signal indicative of the degree of depression of the accelerator pedal (the opening of the accelerator pedal) ACCP, that of the handlebars of the vehicle 10 is actuated, corresponds. In this embodiment, the value ACCP indicative of the opening degree of the accelerator pedal is used as a parameter representing the engine output required by the vehicle driver.

The crank angle sensor 35 is formed by two sensors, namely a reference position sensor and a crank angle sensor. The reference position sensor (not shown) is adjacent to a camshaft of the engine 1 arranged to output a reference pulse signal whenever the camshaft reaches the reference position (for example, whenever a first cylinder of the engine 1 reaches the top dead center on the intake stroke). In other words, the reference pulse signal is output whenever the crankshaft has rotated 720 °. The crank rotation angle sensor is disposed adjacent to the crankshaft to output a crank angle pulse signal whenever the crankshaft rotates by a predetermined angle (for example, 15 °).

In this embodiment, the ECU calculates 30 the revolutions (the rotational speed) ΔNE of the motor 1 according to the interval of the crank rotation angle pulse signal and a momentary rotation phase of the crankshaft according to the number of crank rotation angle pulse signals after the reference pulse signal has been supplied from the reference position sensor.

In addition, the ECU calculates 30 in this embodiment, a change value (a difference value) of the engine revolutions. The change value is used as the vibration torsion parameter, which is the magnitude of the torsional vibrations of the output shaft system of the engine 1 displays. The torsional vibrations of the output shaft system occur as a fluctuation of the rotational speed of the crankshaft of the engine 1 on. Therefore, the change value of the engine revolutions may be used as a parameter characterizing the magnitude (amplitude) of the torsional vibrations. In other words, the crank angle sensor used in this embodiment 35 also works as a vibration detection device.

Although the change value of the revolutions of this embodiment is used as a parameter representing the torsional vibrations, other factors may be used as parameters that characterize the torsional vibrations. For example, the torsional vibrations of the output shaft system of the engine may occur as a change in the acceleration in the forward direction (longitudinal direction) of the vehicle. Therefore, an acceleration sensor for detecting the acceleration of the vehicle 10 in the forward direction to serve as the vibration detecting means and to use the change of the acceleration in the forward direction as a parameter representing the torsional vibrations. The torsional vibrations of the output shaft system of the engine may occur as a change in the torsional moment of the output shaft of the engine. Therefore, a torque sensor for detecting the torque can be added to the output shaft of the motor to serve as a vibration detecting means and to use the change in the torsion torque as parameters representing the torsional vibrations.

As described later, the ECU calculates 30 a value of the fuel injection amount Q _BASE for the engine 1 depending on the operating state thereof (for example, the engine revolutions NE or the accelerator opening ACCP). In addition, the ECU performs 30 A control for preventing torsional vibration by adjusting a correction value Q _JRKFB for the fuel injection amount depending on the value of the detected parameter of the torsional vibration.

An output of the ECU 30 is to a fuel injection valve of each cylinder of the engine 1 via a fuel injection circuit (not shown). Thus, fuel in an amount set in _accordance with Q _BASE and Q _JRKFB is injected into each cylinder at a predetermined fuel injection timing.

Prior to the description of the operation for preventing torsional vibration according to this embodiment, the setting of the fuel injection amount for the engine becomes 1 explained according to this embodiment.

In this embodiment, the ECU calculates 30 a required fuel injection amount Q _GOV depending on the accelerator opening sensor 31 detected accelerator opening ACCP and engine revolutions NE. As described above, accelerator opening ACCP and engine revolutions NE represent a driver requested engine output. The required fuel injection amount Q _{GOV represents} the fuel injection amount required to obtain the requested output and is preliminarily set in the ROM of the ECU 30 stored as a numerical map using accelerator opening ACCP and engine revolution NE. Assuming that the value of the engine rotation NE is constant, the value of Q _GOV is set to be larger as the accelerator opening ACCP increases. On the contrary, when it is assumed that the value of the accelerator opening ACCP is constant, the value of Q _GOV is set to be larger as the engine revolutions NE decrease.

Then the ECU calculates 30 a protection value Q _FULL for the fuel injection amount in response to the engine revolutions NE. Either the guard value Q _FULL or the required fuel injection amount Q _GOV , _whichever is smaller, is set as a value of a basic fuel injection amount Q _BASE .

As explained above, the accelerator opening ACCP immediately increases with no delay depending on the degree of depression of the driver-operated accelerator pedal. Therefore, when the ACCP sharply increases during the acceleration of the vehicle, the value of the required fuel injection amount Q _{GOV also} sharply increases. In fact, however, as the ACCP increases, engine revolutions NE increase relatively smoothly with a time delay. Therefore, when the required amount of fuel injection Q _{GOV is} supplied to the engine, the air in the combustion chamber may become insufficient to generate exhaust smoke. In this embodiment, in order to prevent the generation of smoke upon a sharp increase in load such as acceleration, the upper limit of the fuel injection amount is limited with the guard value Q _{FULL set} in accordance with the engine revolutions NE. The amount of intake air for the engine varies depending on the revolutions. The protection value Q _FULL is set as the maximum fuel injection amount at which no smoke is generated in the exhaust gas at the current engine revolutions. The protection value Q _FULL is obtained by tests or the like to be used as a numerical map in the ROM of the ECU 30 to be saved. The protection value Q _FULL increases as the engine revolutions NE increase.

In other words, the required fuel injection amount Q _GOV sharply increases immediately at the initial acceleration. The protection value However, Q _FULL is maintained at a relatively low value until engine revolutions increase. Therefore, the actual fuel injection amount Q _{BASE is set} to the value Q _FULL (Q _BASE = Q _FULL ). Since the value Q _FULL increases as the engine revolutions NE increase, the value Q _{BASE also} increases. When the engine revolutions NE continue to increase, so that the relationship Q _BASE <Q _{FULL is} reached, the actual fuel injection amount Q _{BASE is maintained} at the value Q _GOV (Q _BASE = Q _GOV ). In this embodiment, the final fuel injection amount Q _{FINC becomes} dependent on of the following equation (1) to prevent torsional vibrations. In the equation (1), the value Q _{JRKFB indicates} a value of the fuel injection amount _correction to prevent torsional vibrations as described later. In other words, in this embodiment, the actual fuel injection amount during acceleration becomes either the guard value Q _FULL or the sum of the fuel injection amount Q _BASE and the correction value Q _JRKFB , _whichever is smaller. Q FINC = MIN (Q FULL , (Q BASE + Q JRKFB )) (1)

A description will be made of a method of setting the fuel injection _correction amount Q _JRKFB for preventing torsional vibration according to the present invention.

2A FIG. 12 is a graph showing the variation of engine revolutions NE during acceleration of the vehicle with lapse of time in a case where the fuel injection correction for preventing torsional vibration is not performed. When the required fuel injection amount Q _GOV sharply increases during acceleration, the actual fuel injection amount Q _BASE is limited by the guard value Q _FULL , as in _FIG 2A shown. Therefore, the value Q _BASE equals the value Q _FULL (Q _BASE = Q _FULL ) and increases relatively smoothly with an increase of the engine revolutions NE. The sharp increase in the output torque due to the increase of the fuel injection quantity induces torsional vibrations in the engine output shaft system. As a result, the engine revolutions NE continue to increase as they change in shape due to the addition of the changes in the revolutions caused by the torsional vibrations (as indicated by the curve II in FIG 2A shown) for smoothly increasing the revolutions corresponding to the increase of the fuel injection amount Q _BASE (Q _FULL ) (as indicated by the straight line I in _FIG 2A indicated) is realized.

The has change component caused by the torsional vibrations a frequency as the resonant frequency (usually about a few Hz in the Case of a wave system of a vehicle) of the torsional vibrations the output shaft of the engine. The amplitude of the change component is with muted over time. The change the engine revolutions caused by the torsional vibrations is changed the acceleration of the vehicle speed. Therefore, it deteriorates the driving behavior of the vehicle.

The torsional vibrations can be prevented by correcting the fuel injection amount so as to prevent the change in engine revolutions. In other words, when the engine revolutions are increased (when the rate of change of engine revolutions takes a positive value), the fuel injection amount is corrected so as to be reduced. When the engine revolutions are reduced (when the rate of change of the engine revolutions takes a negative value), the fuel injection amount is corrected so as to be increased. If the fuel injection amount is corrected only in accordance with the rate of change of the engine revolutions, a problem may arise. 2 B FIG. 15 is a diagram showing an enlarged portion (the circle-enclosed portion B in FIG 2A ) of change of engine revolutions NE during acceleration. It is assumed that the engine revolutions NE per unit time Δt increase by ΔNE during acceleration, as in 2 B shown. In this case, if the fuel injection amount is corrected only in response to the engine rotation NE, the correction amount assumes a negative value (reduction correction) corresponding to the rate of change ΔNE of the engine revolutions .DELTA.NE. In fact, however, the rate of change ΔNE of the revolutions, in addition to the change component caused by the torsional vibrations, includes an increase in the revolutions caused by the acceleration of the engine. If no torsional vibrations are generated, the engine revolutions .DELTA.NE increase evenly as by the 2A and 2 B shown straight line I is indicated. Therefore, the rate of change ΔNE of the revolutions corresponds to the sum of the rate of change component ΔNE _TV caused by the torsional vibrations and the constant acceleration component ΔNE _BASE , as shown by the following equation (2). ΔNE = ΔNE TV + ΔNE BASE (2)

Therefore, when the amount of fuel injection is corrected so as to be reduced in accordance with the value of ΔNE as the revolutions increase during acceleration, the fuel injection amount corresponding to the increase in the revolutions caused by the steady acceleration is undesirably reduced. As a result, an increase in the revolutions caused by the steady acceleration is prevented in an undesirable manner.

As the revolutions decrease, ΔNE _TV assumes negative values. However, the positive values of the component ΔNE _BASE of the continuous acceleration component are maintained as the positive value. Since the absolute value of ΔNE _{BASE is} smaller than the absolute value of ΔNE _TV , the absolute value of ΔNE (the negative value) undesirably becomes smaller than the absolute value of ΔNE _TV . Therefore, when the fuel injection amount is corrected so as to be increased in accordance with the value of ΔNE when the revolutions during the acceleration have been decreased, the correction amount corresponding to the increase of the revolutions caused by the steady acceleration undesirably becomes as in the case where the revolutions have been increased, reduced. As a result, an increase in the number of revolutions caused by the steady acceleration is undesirably prevented. In other words, when the fuel injection amount is corrected in accordance with the value of the rate of change ΔNE of the revolutions, the acceleration performance of the vehicle is limited, thereby causing the problem of deterioration of the acceleration performance.

Therefore, in this embodiment, the constant acceleration component ΔNE _{BASE is} subtracted from the torsional vibration parameter ΔNE so as to extract only the torsional vibration component ΔNE _TV so as to correct the fuel injection amount depending on the vibration component ΔNE _TV .

The through the straight lines I in the 2A and 2 B The specified rate of change is used as the value of ΔNE _BASE . The rate of change ΔNE _BASE indicated by the straight line I can be obtained by removing the torsional vibration component (the change component) from the revolution change curve for smoothing. The smoothed rate of change ΔNE _BASE can be used as a value obtained by arithmetically averaging a rate of change ΔNE of revolutions within a predetermined period of time. The smoothing value ΔNEAV derived from equation (3) is used in this embodiment. ΔNEAV = ΔNEAV i-1 + (ΔNE - ΔNEAV i-1 ) / K (3) where ΔNE is the change rate of revolutions detected at the present time, ΔNEAV _{i-1 is} a smoothing value calculated at the previous time, and K is a smoothing factor.

In other words, the smoothing value ΔNEAV is sequentially calculated as the weighted average value of the smoothing values ΔNEAV _i-1 accumulated until the previous detection and the value ΔNE detected at the present time. The smoothing value K (K> 1) corresponds to the weighting factor for use in the weighted average. The larger K becomes, the greater the degree of smoothing the change of revolutions becomes. The value of K is set to an optimum value obtained from experiments using an actual output shaft system of the engine.

As described above, only the torsional vibration component extracted from the value of the torsional vibration parameter to the fuel injection amount dependent on from the torsional vibration component. Thus, torsional vibrations can the output shaft system of the engine effectively prevented without degrading the acceleration behavior of the vehicle.

3 FIG. 10 is a flowchart of the process for correcting the fuel injection amount for the purpose of preventing torsional vibration according to this embodiment. FIG. This process is executed as a program by the ECU 30 is performed whenever the crankshaft of the engine 1 rotated by a predetermined rotation angle (180 ° in this embodiment).

As in 3 shown at the start of the process, the last engine revolutions ME, in response to the pulse signal from the crankshaft sensor 35 calculated and in the RAM of the ECU 30 saved in step 301 read. Further, the accelerator opening sensor becomes 31 detected accelerator opening ACCP read out.

In step 303 For example, the rate of change ΔNE of the engine revolutions NE is calculated from Equation (4), where ΔNE _i-1 means the engine revolutions read during the execution of the process in the previous process, while ΔNE _{i-1 means} a value determined in step 315 is updated every time the previous task is executed. ΔNE = ΔNE - ΔNE i-1 (4)

In step 305 is the continuous component ΔNEAV from in step 303 is subtracted according to equation (5) calculated value .DELTA.NE, so that the vibration component .DELTA.NE _{TV is} calculated. The continuous component ΔNE _TV can be calculated by using the smoothing factor K for sequentially smoothing ΔNE (step 313 ). .DELTA.Ne TV = ΔNE - ΔNEAV (5)

In step 307 will the fuel injection kor correction quantity Q _{JRKFB is calculated} as a function of the calculated torsional vibration component ΔNE _TV . In this embodiment, Q _JRKFB is calculated as a value obtained by multiplying the torsional vibration component ΔNE _TV by a negative constant α as shown in Equation (6). Q JRKFB = α × ΔNE TV (α <0) (6)

As a result, the value of the correction _amount Q _{JRKFB is set} as a value which is increased in proportion to the change (rate of change) of the revolutions caused by the torsional vibrations and has an inverse sign. In other words, when the revolutions caused by the torsional vibrations increase, the previous value is set as the negative value to cancel the change. When the revolutions are reduced, the previous value is set as a positive value.

After calculating the fuel injection _correction amount Q _JRKFB in the above-described manner, in step 209 a process for preventing the pendulum or rocking performed. In step 309 it is determined whether the possibility of rocking exists or not. If it is determined that there is a possibility of rocking, the value of the correction _amount Q _JRKFB is set to zero to prevent a correction of the fuel injection. The rocking preventing process in step 309 will be described later.

After the step of determining the rocking has been completed, the correction _amount Q _JRKFB is used to determine the final fuel injection amount Q _FINC in step 311 adjust. In the following step 313 the existing value of the rotational change rate ΔNE is used to again calculate the value of the aforementioned steady component (the smoothing value) ΔNEAV. In step 315 the value of NE _{i-1 is} updated for the xt operation, thus completing the previous operation.

4 _{FIG. 15} is a flowchart of a process for setting the final fuel injection amount Q _{FINC of FIG} 311 is carried out.

In step 401 The engine revolutions NE and the accelerator opening degree ACCP, which are in step 301 were read out as in 3 shown used to obtain the required fuel injection quantity Q _GOV from the ROM of the ECU 30 read out the stored numeric card. In step 403 Similarly, the value of NE is used to express the protection value Q _FULL for the fuel injection amount from that in the ROM of the ECU 30 read out the stored numeric card.

In step 405 For example, the basic fuel injection amount Q _{BASE is set to} either the value Q _GOV or the value Q _FULL , _whichever is smaller, depending on equation (7). Q BASE = MIN (Q GOV , Q FULL ) (7)

In step 407 is the fuel injection _correction amount Q _SRKFB , which in the in 3 shown steps 307 and 309 calculated and used to prevent torsional vibration, used to set the fuel injection amount Q _FIN according to equation (8). Q FIN = Q BASE + Q JRKFB (8th)

Since Q _{JRKFB is set} as a large value when the torsional vibrations are relatively strong, this embodiment has a configuration in which the value Q _FIN calculated in Equation (8) is restored to the step of using the guard value Q _FULL 309 is limited. According to Equation (9), the final fuel injection amount Q _{FINC is} calculated. Q FINC = MIN (Q FIN , Q FULL ) (9)

In step 411 the value of the final fuel injection amount Q _FINC for the fuel injection _{circuit is} set and the above operation is ended.

As a result, that becomes the engine 1 Corrected to be supplied fuel injection amount to eliminate the change of the revolutions generated only by the torsional vibrations. Therefore, the torsional vibrations can be prevented without deteriorating the acceleration performance of the vehicle.

The one in step 309 carried out and in 3 will now be described. In this embodiment, the torsional vibration prevention control is performed at a revolution change (which is a change in revolutions for each cylinder of a 4-cylinder 4-cycle engine used in this embodiment) which is detected whenever the crankshaft of the engine is 180 degrees rotates. However, the combustion conditions of the actual engine differ slightly depending on the respective cylinders, even if no torsional vibrations are generated. Therefore, the output torque is different from the corresponding cylinders. Despite the steady state of operation, the change in torque, the engine revolutions in the explosion strokes of ent changing speaking cylinder. Therefore, there is a possibility of rocking when the cycles for detecting the change of the revolutions to prevent the torsional vibrations coincide with the cycles of the changes of the revolutions of the respective cylinders. If no torsional vibration is generated, the change in the revolutions of the respective cylinders undesirably during the in 3 shown control detected as .DELTA.NE. Therefore, the error in the correction of the fuel injection amount may cause the change of the revolutions to be undesirably increased.

In this embodiment, depending on a timing pattern of the sign inversions of the torsional vibration component ΔNE _{TV shown} in step 305 in 3 calculated, whether the possibility of a rocking exists or not. When it is determined that the pattern is generated to effect rocking, the correction of the fuel injection amount is interrupted (ie, the correction _amount Q _{JRKFB set} to zero, Q _JRKFB = 0), so that rocking caused by an error in the correction of the fuel injection amount is prevented becomes.

Now, the determination of the rocking according to this embodiment will be described. In this embodiment, the variation component ΔNE _{TV is} calculated whenever the crankshaft rotates through 180 °. In this embodiment, since a four-cylinder four-cycle engine is used, the fuel injection is performed at an angular interval of 180 °. Therefore, if the sign of ΔNE _{TV is} reversed at each calculation operation (every 180 °), the fuel injection amount has been excessively corrected so that it is determined that the fuel injection amount has been excessively corrected. As a result, it is determined that a rocking has occurred. If the sign of ΔNE _TV is positive in the previous calculation, the correction is made to decrease the fuel injection amount and decrease the revolutions. In this case, if the sign of the present value ΔNE _TV is negative in the present calculation process, an excessive amount has been reduced in the previous correction injection amount. This means that the engine revolutions have decreased excessively. Therefore, the fuel injection amount Q _BASE is corrected to be increased at the current correction. Therefore, if the sign of ΔNE _{TV is} reversed at each calculation (every 180 °), the fuel injection amount is alternatively corrected so as to be reduced and increased. Therefore, the control process is likely to become unstable, so there is a possibility of rocking.

In the following case, a rocking occurs:
When the sign of ΔNE _{TV is} reversed at intervals of two computations (ie, one revolution of the motor of (180 ° x 2 = 360 °)) (for example, in the case where the subsequent inversion repeats, with a positive value during one revolution of the engine and a negative value during the subsequent one revolution of the engine is assumed); and
when the succeeding inversion is repeated, in which the sign of ΔNE _TV successively takes a positive (or negative) value three times and then the sign assumes a negative (or positive) value at the next time point.

Therefore, in this embodiment, the influence of a detection error caused by noise and disturbance influences is added to the previous patterns, so that the in 6 shown Aufschaukelmuster preparatory set. This in 6 shown Aufschaukelmuster will be described below.

5 FIG. 10 is a flowchart showing the swing-up prevention process performed in step. FIG 309 in 3 is carried out.

In step 501 it is determined whether the sign of ΔNE _TV , which value in step 305 of the 3 has been computed in relation to the value calculated in the previous procedure (whether the sign was inverted or not). If the sign was not inverted, the process moves to step 505 before, by the count of a counter C ₁ is increased by one. In the steps 507 and 509 For example, the limiting operation is performed such that the value of C ₁ does not exceed the maximum value C _MAX . As a result, the count value of the counter C _{1 is raised} to the maximum value C _MAX when the sign of ΔNE _TV is maintained as either positive or negative.

When in step 501 it is determined that the sign of ΔNE _{TV has been} inverted, the process goes to step 503 by substituting the values of the counters C ₂ and C ₁ for the values of the counters C ₃ and C ₂ . In addition, the value of the counter C _{1 is set} to 1.

As a result, the hysteresis of reversing the sign of ΔNE _TV in the three previous operations is stored in the counters C ₃ , C _2, and C ₁ .

For example, the relationship C ₃ = C ₂ = C ₁ = 1 reflects that the sign of ΔNE _{TV was} inverted every time. The relationship C ₃ = C ₂ = 2 again indicates that the sign of ΔNE _TV was inverted twice in two operations. The relationship C ₃ = 3 and C ₂ = 1 or C ₃ = 1 and C ₂ = 3 represents the cycle of change in which the value ΔNE _TV repeatedly takes the value of the same sign three times and then the value of the inverted one Takes a sign.

In step 511 a rocking is determined as a function of the counters C ₁ , C ₂ and C ₃ . In step 511 will depend on an in 6 shown card determines whether the possibility of a rocking exists or not.

• A: C₃ = C₂ = 1
• B: C₃ = C₂ = 2
• C: C₃ = 3, C₂ = 1
• D: C₃ = 1, C₂ = 3

6 shows a map with an ordinate on which the values of the counter C ₂ are given and an abscissa representing the values of the counter C ₃ . The points A-D shown in the map correspond to the following relationships:

• A: C ₃ = C ₂ = 1
• B: C ₃ = C ₂ = 2
• C: C ₃ = 3, C ₂ = 1
• D: C ₃ = 1, C ₂ = 3

In other words, the point A represents a reversal of the sign of ΔNE _TV in each process. B represents a reversal of the sign of ΔNE _TV once in two operations, and C and D illustrate a continuation of the same sign in three successive operations, followed by an inverted sign only once. The above conditions are representative examples in which rocking occurs. In other words, the points A-B on the map are basic conditions for determining the occurrence of rocking. Therefore, in this embodiment, when the combination of the counters C ₃ and C ₂ corresponds to one of the points A to D, it is determined that warping has occurred. In actual operation, the detection of engine revolutions ME is associated with an error due to noise or disturbance effects. Therefore, the determination of the possibility of rocking can not be accurately performed only depending on the basic conditions. Thus, in this embodiment, the effects of noise effects u. ä., so that the possibility of a rocking is determined when the values of C ₂ and C ₃ in the diagonal line area on the in 6 shown card fall. The in 6 Diagonal line range shown is defined by the lines expressed by the following equations: C ₂ = C ₃ + 2 (line I), C ₂ = C ₃ - 2 (line II) and C ₂ = - C ₃ + 8 (line III). In other words, the conditions for determining rocking according to this embodiment are as follows. C 3 - 2 ≤ C 2 ≤ C 3 + 2 and C 2 + C 3 ≤ 8

While progressing the operations of step 501 to 505 the values of C ₂ and C _{3 are} left unchanged. Therefore, if rocking is detected once under the above-mentioned determination conditions, the determination of the rocking is not canceled even if the sign of ΔNE _{TV is} no longer inverted. Therefore, in this embodiment, a state in which the value of the counter C ₁ in step 511 is less than the value of the counter C ₂ or C ₃ , added to the conditions for determining the rocking. The fact that the value of C _{1 is} less than the value of C ₂ or C ₃ again indicates that the number of times that ΔNE _{TV has been kept} at the same sign has been decreased compared to the previous number of times Has. In other words, the rocking has been strengthened. If the value of C _{1 is} greater than both values of C ₂ and C ₃ , it is determined that the rocking has been eliminated.

In other words, the conditions in which an occurrence of rocking in step 511 from 5 is determined are as follows: C 3 - 2 ≤ C 2 ≤ C 3 + 2; and C 2 + C 3 ≤ 8; and C 1 ≤ C 2 or C 1 ≤ C 3

When the counters C ₁ , C ₂ and C ₃ satisfy the above conditions in step 511 fulfill, ie if there is currently the possibility of rocking, the process moves to step 513 before, where the value in step 307 according to 3 set correction _amount Q _{JRKFB is set} to zero. As a result, the value falls in step 409 according to 4 set final fuel injection amount Q _FINC with the value Q _BASE together. In the foregoing case, rocking is caused by the correction of the fuel injection amount for the purpose of preventing torsional vibration, resulting in the possibility of increased vibration or unsteady control. Therefore, a correction of the fuel injection amount is not performed. If the values of the counters do not meet the above mentioned conditions in step 511 and there is no possibility of rocking, the value of the correction _amount Q _{JRKFB is} kept unchanged and the process is terminated in this state. As a result, the correction of Kraftstoffein injection amount for preventing torsional vibration is performed.

It is preferred that the in 6 shown diagonal line range is determined by experiments using an actual engine and output shaft system.

In the in 5 shown step 513 the correction _amount Q _JRKFB is set to zero and the Correction of the fuel injection amount in case of possibility of rocking not performed. The value of the correction _amount Q _JRKFB may also be _reduced instead of the setting of Q _JRKFB = 0 according to Equation (10). Thus, the control gain is reduced and the torsional vibrations are controlled to a certain degree while preventing rocking. Q JRKFB = Q JRKFB × β (β <1) (10)

As explained above, can According to the invention, torsional vibrations be effectively prevented without the engine acceleration characteristics be worsened.

An apparatus and a method for controlling fuel injection in an internal combustion engine (US Pat. 1 ) for preventing torsional vibration of the internal combustion engine without deteriorating the acceleration performance. The device is equipped with a control unit (an ECU) ( 30 ) for controlling the fuel injection quantity for the diesel engine ( 1 ) of a vehicle ( 10 ) Mistake. The ECU ( 30 ) calculates the rate of change ΔNE of the engine revolutions in response to an input from a crank angle sensor ( 35 ) and subtracts a value obtained by smoothing a change component ΔNE from ΔNE to extract a torsional vibration component therefrom. In addition, the ECU corrects ( 30 ) the amount of fuel injection of the engine for reducing the torsional vibration component. Since the extracted torsional vibration component during an acceleration or the like does not contain a continuous change in the revolutions, the steady change in the revolutions caused only by the acceleration is not affected by the correction of the fuel injection amount. Therefore, deterioration of the acceleration performance caused by preventing the torsional vibration can be prevented.

Claims (8)

Device for controlling the fuel injection in an internal combustion engine ( 1 ) with a vibration detection device for detecting a state quantity that determines the amplitude of torsional vibrations of an output shaft system ( 5 . 8th ) of a vehicle ( 10 ), as a torsional vibration parameter (ΔNE) and a fuel injection amount correcting means for correcting the fuel injection amount (Q _FIN ) of the internal combustion engine ( 1 ) to prevent torsional vibrations in response to the detected torsional vibration parameter (ΔNE); wherein the fuel injection quantity correcting means can detect and store a value (ΔNE _AV ) obtained by smoothing the torsional vibration parameter (ΔNE) which has occurred within a predetermined time period (Δt) as a component of steady acceleration; vibration component extraction means is provided for extracting a torsional vibration component (ΔNE _TV ) from the detected torsional vibration parameter (ΔNE) using the steady acceleration component; the fuel injection quantity correction means further the fuel injection quantity (Q _FIN) can correct (.DELTA.Ne _TV) in dependence on the magnitude of said torsional vibration to a vibration correction quantity (Q _JRKFB) of the fuel injection quantity (Q _FIN) in accordance with the extracted torsional vibration component (.DELTA.Ne _TV) to calculate and _{To add} a vibration _{correction amount} (Q _JRKFB ) to a fuel injection amount (Q _FIN ) set in _accordance with an operating condition of the internal combustion engine so as to correct the fuel injection amount (Q _FIN ), characterized in that the fuel injection amount correcting means determines the absolute value of the vibration _{correction amount} (Q _JRKFB ) when a timing pattern of the sign inversions of the torsional vibration component (ΔNE _TV ) coincides with a predetermined pattern. A fuel injection control apparatus according to claim 1, characterized in that the vibration _{correction amount} (Q _JRKFB ) is set to zero when the timing pattern of the sign inversions of the torsional vibration component (ΔNE _TV ) coincides with a predetermined rocking pattern. Device for controlling the fuel injection according to claim 1, characterized in that the Torsionsvibrationsparameter (ΔNE) of the rate of change the revolutions of the internal combustion engine, the rate of change of the acceleration in the forward direction or the rate of change the torsional moment of the internal combustion engine is formed. A fuel injection control apparatus according to claim 3, characterized in that said fuel injection amount correcting means may interrupt the correction of fuel injection when the timing pattern of the sign inversions of the torsional vibration component (ΔNE _TV ) coincides with the predetermined pattern. Method for controlling fuel injection in an internal combustion engine ( 1 ) with a vibration detection device for detecting a state variable that the amplitude of torsional vibrations of the output shaft system ( 5 . 8th ) of a vehicle ( 10 ), as a torsional vibration parameter (ΔNE) and a fuel injection amount correcting means for correcting a fuel injection quantity (Q _FIN ) of the internal combustion engine ( 1 ) to Torsi to prevent vibrations due to the detected torsional vibration parameter (ΔNE), comprising the steps of: storing a rate of change of the torsional vibration parameter (ΔNE) obtained by smoothing the torsional vibratlon parameter (ΔNE) as a component of a steady-state within a predetermined period of time (Δt) Acceleration has occurred; Extracting a torsional vibration component (ΔNE _TV ) from the detected torsional vibration parameter (ΔNE) using the continuous acceleration component; Correcting the fuel injection amount (Q _FIN ) depending on the magnitude of the torsional vibration component (ΔNE _TV ); Extracting the torsional vibration component (ΔNE _TV ) at a predetermined time interval; and calculating a vibration _{correction amount} (Q _JRKFB ) of the fuel injection amount (Q _FIN ) in response to the extracted torsional vibration component (ΔNE _TV ) and adding the vibration _{correction amount} (Q _JRKFB ) to a fuel injection amount (Q _BASE ) set in _accordance with an operation state of the internal combustion engine to correct the fuel injection amount (Q _BASE ) characterized by decreasing the absolute value of the vibration correction amount when a timing pattern of the sign inversions of the torsional vibration component (ΔNE _TV ) coincides with a predetermined pattern. A method of controlling fuel injection according to claim 5, characterized in that the vibration correction amount (Q _JRKFB ) is set to zero when the timing pattern of sign inversions of the torsional vibration component (ΔNE _TV ) coincides with a predetermined rocking pattern. Method for controlling fuel injection according to claim 5, characterized in that the Torsionsvibrationsparameter (ΔNE) of the rate of change the revolutions of the internal combustion engine, the rate of change of the acceleration in the forward direction or the rate of change the torsional moment of the internal combustion engine is formed. A fuel injection control method according to any one of claims 5 to 7, characterized in that said fuel injection amount correcting means stops the fuel injection correction when the timing pattern of the sign invasions of the torsional vibration component (ΔNE _TV ) coincides with the predetermined pattern.