阅读说明：本技术 用于确定用于调整进气管压的调整量的方法和调节回路 (Method and control circuit for determining an adjustment quantity for adjusting an intake manifold pressure ) 是由 M.贾万 S.亨策尔特 M.邦耶斯 于 2019-03-21 设计创作，主要内容包括：本发明涉及用于确定用于调整进气管压的调整量的方法和调节回路,具体而言本发明涉及一种用于以理论进气管压<Image he="23" wi="44" file="100004_DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>为出发点确定用于调整内燃机的进气管(10)中的进气管压的调整量的方法,其中,理论进气管压<Image he="23" wi="44" file="665981DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>根据调整量界限值<Image he="22" wi="95" file="100004_DEST_PATH_IMAGE004.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>和/或由调整量界限值影响的量<Image he="23" wi="165" file="100004_DEST_PATH_IMAGE006.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>来修正。此外,本发明涉及一种用于实施这样的方法的调节回路。(The invention relates to a method and a control circuit for determining an adjustment quantity for adjusting an intake manifold pressure, in particular to a method for adjusting a target intake manifold pressure Method for determining an adjustment quantity for adjusting an intake manifold pressure in an intake manifold (10) of an internal combustion engine for starting points, wherein a target intake manifold pressureAir pipe pressure According to the regulation limit value And/or the quantity influenced by the adjustment quantity limit value To correct it. The invention further relates to a control loop for carrying out such a method.)

1. For using theoretical intake pipe pressureMethod for determining an adjustment quantity for adjusting an intake manifold pressure in an intake manifold (10) of an internal combustion engine for starting points, wherein the target intake manifold pressureAccording to the regulation limit valueAnd/or the quantity influenced by the adjustment quantity limit valueTo correct it.

2. The method according to claim 1, wherein the adjustment amount threshold comprises a maximum throttle opening area of a throttle valve (11) in the intake pipe (10)And/or a minimum throttle opening area of the throttle valve (11)And/or the quantity influenced by the adjustment quantity limit valueIs an amount that contains the maximum throttle opening area by means of the saidAnd/or the minimum throttle opening areaLimited throttle opening area。

3. A method according to claim 1 or 2, wherein the adjustment amount is adjusted by means of PI-adjustment of the corrected theoretical intake pipe pressure, the adjusted theoretical intake pipe pressure being brought to an undefined adjustment amountNon-linear transformation and undefined adjustment in (1)By means of the regulating value limitIs determined by the definition of (a).

4. Method according to any of the preceding claims, wherein the adjustment amount limit value is setOr a quantity influenced by the adjustment quantity limit valueFor the starting point, a determination is made by means of a changeover (50,70) for correcting the set intake manifold pressureThe theoretical intake pipe pressure correction value of (1).

5. The method of any one of claims 2 to 4Method, wherein the maximum throttle opening areaIs converted to the maximum achievable intake pipe pressureAnd the minimum throttle opening areaIs converted (50) to a minimum achievable intake manifold pressureAnd the theoretical intake pipe pressureAccording to the maximum achievable intake pipe pressure being convertedAnd the minimum achievable intake pipe pressure being switchedTo define (51).

6. The method of the preceding claim, wherein the maximum throttle opening areaTo the maximum achievable intake pipe pressureThe transformation (50) in (2) is based on the following relationship:

(ii) a And is

Wherein the minimum throttle opening area to the minimum achievable intake pipe pressureThe transformation (50) in (2) is based on the following relationship:

,

wherein the content of the first and second substances,is a predicted change in the intake pipe pressure,is the measured intake pipe pressure, b is the variable affected by flow through the throttle, leakage through the throttle, mass flow through the throttle and pmodulation,is the maximum throttle opening area andis the minimum throttle opening area.

7. The method of any of claims 2-4, wherein at an undefined throttle opening areaAnd a defined throttle opening areaThe difference between them is converted (70) into a pressure differenceAnd the theoretical intake pipe pressureAccording to the converted pressure differenceTo match (71).

8. Method according to the preceding claim, wherein the pressure difference for determining (70) the transitionThe following applies:

，

where c is a variable affected by P regulation and flow through the throttle,is a defined throttle opening area andis an undefined throttle opening area.

9. For using theoretical intake pipe pressureFor this purpose, a control circuit (4;6) for controlling an adjustment quantity of an intake manifold pressure in an intake manifold (10) of an internal combustion engine is determined, wherein the control circuit (4;6) comprises a limit value for the adjustment quantityAnd/or the quantity influenced by the adjustment quantity limit valueCorrecting the theoretical inlet manifold pressureA correction unit (41; 61).

10. The regulating circuit according to claim 9, further comprising a reverse-direction switching device (41;61) configured for switching the adjustment quantity limit valueOr a quantity influenced by the adjustment quantity limit valueDetermining a target point for correcting the target intake pipe pressure by means of a changeoverThe theoretical intake pipe pressure correction value of (1).

Technical Field

The invention relates to a method and a control circuit for determining an adjustment variable, for example a throttle opening area or a throttle position, for adjusting an intake manifold pressure in an intake manifold of an internal combustion engine, for example of a motor vehicle.

Background

Precise regulation of the intake pipe pressure plays an important role for efficient, comfortable and low-cost operation of the internal combustion engine. However, manufacturing tolerances depending on various components, such as the throttle valve, may cause defective determination and adjustment of the intake pipe pressure. This can, for example, lead to a wobbling throttle movement in the case of a component with tolerance on the fresh air side, as a result of which a racing operation is detectable by the driver, or in the case of a defective, for example unsealed, system, a wobbling throttle movement, which is not reliably detected, as a result of which a triggered (toggelden) release of the intake manifold leakage diagnosis is caused.

When trying to reach a target value, here the target intake manifold pressure, in which the manipulated variable assumes a manipulated variable limit value, the control path (Strecke) is not controllable over a long period of time (ausregeln, sometimes referred to as correction), whereby the I-section continues to increase (saturate), when trying to reach another target value, in which the manipulated variable assumes a value between the manipulated variable limits, a strong overshoot (Ü bergschwingen) or even instability of the regulator can be caused, since the high I-section must first be reduced again as a result of the overshoot.

Therefore, so-called anti-saturation has hitherto been used in order to circumvent the saturation effect. For this purpose, the I-section of the regulator can be frozen (einfrieren, sometimes referred to as fixed) in the case in which the adjustment variable assumes the adjustment variable limit value, i.e. the state of the regulation is fixed, and a cyclic reinitialization can be carried out, here for example with a lower or upper mechanical stop of the throttle flap. However, continuous operation of the regulation is not possible and there is no common reinitialization requirement for all operating conditions, so that very high coordination and safeguarding costs are necessary.

Similar solutions are also known from the field of electric motors, as described in DE 102009000609 a1 and DE 102015118980 a 1.

Disclosure of Invention

The object of the present invention is to provide a method and a control circuit for determining an adjustment quantity for adjusting an intake manifold pressure, which at least partially overcome the above-mentioned disadvantages.

This object is achieved by the method according to the invention for determining an adjustment quantity for adjusting an intake manifold pressure according to claim 1 and the control circuit according to the invention according to claim 9.

According to a first aspect, the invention relates to a method for determining an adjustment variable for adjusting an intake manifold pressure in an intake manifold of an internal combustion engine, starting from a target intake manifold pressure, wherein the target intake manifold pressure is corrected as a function of an adjustment variable limit value and/or a variable influenced by the adjustment variable limit value.

According to a second aspect, the invention relates to a control circuit for determining an adjustment variable for adjusting an intake manifold pressure in an intake manifold of an internal combustion engine starting from a target intake manifold pressure, wherein the control circuit comprises a correction unit for correcting the target intake manifold pressure as a function of an adjustment variable limit value and/or a variable influenced by the adjustment variable limit value.

Further advantageous embodiments of the invention result from the following description of preferred embodiments of the invention and the dependent claims.

The invention relates to a method for determining an adjustment quantity for adjusting an intake manifold pressure in an intake manifold of an internal combustion engine. The adjustment amount may be, for example, a throttle valve opening area (throttle leakage area) or a throttle position of a throttle valve disposed in an intake pipe. The internal combustion engine may be an internal combustion engine of a motor vehicle, such as a gasoline engine or a diesel engine.

In the case of the determination of the manipulated variable, starting from a target intake manifold pressure, which is preferably determined as a function of the current operating state of the internal combustion engine and the driver's expectations. According to the method according to the invention, the target intake manifold pressure is then corrected as a function of the manipulated variable limit value, preferably the upper manipulated variable limit value and the lower manipulated variable limit value and/or the quantity influenced by the manipulated variable limit value, preferably the quantity influenced by the upper manipulated variable limit value and the lower manipulated variable limit value. The adjustment value limit, in particular the upper adjustment value limit and the lower adjustment value limit, can be determined by the design of the internal combustion engine, in particular by the design of the throttle valve, and if appropriate the arrangement of the throttle valve in the intake manifold.

The correction of the target intake manifold pressure as a function of the manipulated variable limit and/or the variable influenced by the manipulated variable limit can limit the target intake manifold pressure in such a way that a value of the manipulated variable outside the manipulated variable limit is no longer sought. The invention thus provides for the use of a method for continuously operating a non-linear pressure regulation over a throttled region while avoiding saturation of an integrator in the control loop. The reinitialization provisions with all the disadvantages thus become redundant and the application and safeguarding costs can be significantly reduced.

In some embodiments, the adjustment threshold may include a maximum throttle opening area of the throttle valve and/or a minimum throttle opening area of the throttle valve in the intake pipe. Preferably, the upper adjustment limit is a maximum throttle opening area of the throttle valve and the lower adjustment limit is a minimum throttle opening area of the throttle valve. Alternatively, the adjustment limit value may include a first throttle position (in which the throttle is maximally opened) and/or a second throttle position (in which the throttle is maximally closed). In the first throttle position, the throttle valve may be opened to such an extent that the throttle valve opening area is at least 90% of the cross-sectional area of the intake pipe. In the second throttle position, the throttle valve can still be opened slightly, for example up to 5%, in particular up to 2%, of the full opening of the throttle valve in the first throttle position.

The quantity influenced by the adjustment quantity limit value may be a quantity that contains a throttle opening area defined by means of a maximum throttle opening area and/or a minimum throttle opening area. Alternatively, the quantity influenced by the adjustment quantity limit value may be a quantity which contains a throttle position defined by means of the first throttle position and/or the second throttle position.

In the case of defining the adjustment amount, it can be checked whether the value of the adjustment amount is greater than the upper adjustment amount limit value, and when this is the case, the adjustment amount can be made to coincide with the upper adjustment amount limit value. When this is not the case, it may be checked whether the value of the adjustment amount is smaller than the lower adjustment amount limit value, and when this is the case, the adjustment amount may be made to coincide with the lower adjustment amount limit value. When this is not the case, the adjustment amount is in the range from the upper adjustment amount limit value to the lower adjustment amount limit value and the adjustment amount is kept unchanged. Alternatively, it may also be checked first whether the value of the adjustment variable is smaller than the lower adjustment variable limit value and, subsequently, whether the value of the adjustment variable is larger than the upper adjustment variable limit value. The definition may also be implemented in other ways.

In some embodiments, the adjustment quantity may be determined by means of a PI regulation of the corrected setpoint intake pipe pressure, a non-linear conversion of the regulated setpoint intake pipe pressure into an undefined adjustment quantity, and a limitation of the undefined adjustment quantity by means of an adjustment quantity limit value. The defined adjustment variable may be a defined throttle opening area, which is determined as described above by means of an adjustment variable limit value, in particular by means of a maximum throttle opening area and a minimum throttle opening area. The throttle position may be calculated from the defined throttle opening area. Alternatively, the defined adjustment amount may be a defined throttle position, which may be defined similarly to defining a throttle opening area.

The PI regulation may be based on the criteria of a conventional PI regulator, i.e. including the determination of the P part (proportional part) and the I part (integral part). The non-linear transformation may be based on a non-linear correlation of the effect of the characteristics or current operating conditions for the throttle on the intake pipe pressure. The non-linear correlation can be influenced, for example, by the leakage Offset (package Offset) of the throttle valve, the mass flow through the throttle valve, the pressure before the throttle valve and the pressure after the throttle valve. The leakage offset is a function of component tolerances in the intake manifold, in particular the throttle valve, which can lead to an undesirable oscillating throttle movement. In particular, the limitation can be achieved by means of the area limits, i.e. the maximum throttle opening area and the minimum throttle opening area, as described above.

In some exemplary embodiments, the variable limit value may be set or a target intake manifold pressure correction value for correcting the target intake manifold pressure may be determined by means of a changeover starting from the variable influenced by the variable limit value. In the case where the adjustment amount is the throttle opening area, the switching of the adjustment amount limit value may be a reversal similar to a reversal (sometimes referred to as a conversion) of the throttle opening area. For example, the upper and lower throttle opening areas or defined throttle opening areas may be reversed.

The conversion may preferably be a reverse conversion (R ü cktransformations, sometimes referred to as an inverse conversion) with respect to a conversion of a modified, adjusted theoretical intake pipe pressure, which may thus be a conversion of a non-linear adjustment amount limit value, which preferably causes an adjustment amount limitation, into a state region of the regulator.

Cyclic throttle oscillations in the event of a leakage of the throttle valve, for example in idle, can be eliminated in an effective and simple manner by correcting the setpoint intake manifold pressure. The switch box and application of reinitialization parameters may be abandoned.

In some embodiments, the upper adjustment volume limit value, in particular the maximum throttle opening area, may be converted to a maximum achievable intake pipe pressure, and the lower adjustment volume limit value, in particular the minimum throttle opening area, may be converted to a minimum achievable intake pipe pressure, and the theoretical intake pipe pressure is defined in accordance with the converted maximum achievable intake pipe pressure and the converted minimum achievable intake pipe pressure. This definition may be achieved similar to the above definition of throttle opening area. The target intake manifold pressure can therefore be accurately limited to the limit, which does not allow a violation of the manipulated variable limit, i.e. neither exceeds the upper or falls below the lower manipulated variable limit. This improves the performance and at the same time reduces the application and maintenance effort.

In some embodiments, the maximum throttle opening area to the maximum achievable intake pipe pressureThe transformation in (3) may be based on the following relationship:

(1)

in this case, the amount of the solvent to be used,is a predicted change in the intake pipe pressure, which is preferably determined by means of a model of the influence of the throttle valve and/or a model of the intake pipe pressure and the I-regulation,is a measured intake pipe pressure, b is a variable that is affected by flow through the throttle, leakage through the throttle, mass flow through the throttle, and P-regulation, anIs the maximum throttle opening area. The transformation may be based on, inter alia, the following relationship:

(1a)

in this case, the amount of the solvent to be used,is the flow factor through the throttle valve and,is a strengthening factor for the regulation of P,is a leakage-offset, andis the mass flow through the throttle.

Accordingly, minimum throttle opening area to minimum achievable intake pipe pressureThe transformation in (3) may be based on the following relationship:

(2)

in this case, the amount of the solvent to be used,is the minimum throttle opening area. In particular, the transition to the minimum throttle opening area may be based on the relationship:

(2a)

non-linear adjustment limit values, in particular upper adjustment limit values, can be realized by means of equations (1) and (2) or equations (1a) and (2a)And lower adjustment thresholdThe reverse conversion of (1).

Similarly, the maximum achievable intake manifold pressure may be switched from the first throttle position and the minimum achievable intake manifold pressure may be switched from the second throttle position.

The limitation of the target intake pipe pressure to the permissible range of adjustment values can be achieved by means of the adjustment value limit value of the reversal transition, and saturation effects can be reliably avoided.

In some embodiments, the difference (Differnz, sometimes referred to as a difference) between the undefined adjustment amount and the defined adjustment amount, for example, between the undefined throttle opening area and the defined throttle opening area, may be converted to a pressure differential and the theoretical intake pipe pressure may be matched based on the converted pressure differential. A continuous reversal of the undefined difference from the defined adjustment amount to the desired theoretical inlet pipe pressure can thus be carried out.

In some embodiments, to determine the differential pressure of the transitionApplicable are:

(3)

where c is a variable, which is influenced by Padjustment and the flow factor through the throttle,is a defined throttle opening area andis an undefined throttle opening area.

Preferably, the nonlinear unrestricted and restricted throttle opening areas are inversely transformed according to the following relationship:

(3a)

in this case, the amount of the solvent to be used,is a potentiator of P regulation.

Similarly, the converted pressure differential may also be converted from a difference between a defined throttle position and an undefined throttle position.

A reversal of the direction of the difference in the switched, defined and undefined adjustment quantities to the inlet of the integrator of the pressure regulator can thus be achieved. The backward guidance preferably leads to an algebraic ring (algebraischen schleife). This can however be solved by fixed point iteration.

The correction of the setpoint intake manifold pressure not only as a function of the manipulated variable limit value, in particular the upper manipulated variable limit value and the lower manipulated variable limit value, but also as a function of a variable influenced by the manipulated variable limit value, in particular as a function of a difference between a defined and an undefined manipulated variable, is suitable for eliminating a pivoting of the throttle valve. Both concepts may exhibit a rapid negative load impact (Lastschlag).

The invention further relates to a control circuit for determining an adjustment variable for adjusting an intake manifold pressure in an intake manifold of an internal combustion engine starting from a target intake manifold pressure, wherein the control circuit comprises a correction unit for correcting the target intake manifold pressure as a function of an adjustment variable limit value and/or a variable influenced by the adjustment variable limit value. For example, the control loop comprises an interference observer, a PI controller, a nonlinear converter, an adjustment limiter and a correction unit. The control circuit is preferably designed to carry out a method for determining an adjustment quantity for adjusting the intake manifold pressure, as described above. The regulating circuit may form part of an engine control system of an internal combustion engine of a motor vehicle. The saturation effect of the integrator in the control loop can be effectively prevented by correcting the theoretical intake manifold pressure.

In the case where the adjustment amount is the throttle opening area, the regulator may further include a scaling unit for calculating the throttle position from the defined throttle opening area.

The control loop may furthermore comprise an adjustment unit for adjusting the determined throttle position. The intake pipe pressure is adjusted by adjustment of the throttle position.

In some exemplary embodiments, the control circuit may furthermore comprise a reverse switching device, which is designed to determine a target intake manifold pressure correction value for correcting the target intake manifold pressure by means of a switching operation, starting from the control variable limit value or a variable influenced by the control variable limit value, as described in detail above.

The invention is characterized by the inverse transformation of the adjustment quantity limited to the state space of the linear part of the regulator and the co-action of the overall system between anti-saturation (back guidance of the inverse transformation based on the limited adjustment quantity), the non-linear pressure regulator and the parallel model of the closed regulation loop including integrators for ensuring stable accuracy.

Drawings

Embodiments of the invention will now be described, by way of example and with reference to the accompanying drawings. Wherein:

FIG. 1 schematically shows a drive assembly and a diagram of a control device with a regulating circuit for determining a throttle opening area;

FIG. 2 schematically illustrates a conventional regulation loop;

fig. 3 schematically shows a first embodiment of a regulating circuit according to the invention with a theoretical inlet pipe pressure defined;

FIG. 4 shows a flowchart of a method for determining with the regulating circuit of the first embodiment an adjustment amount for adjusting an intake pipe pressure in an intake pipe of an internal combustion engine;

fig. 5 schematically shows a second embodiment of the regulating circuit according to the invention with a theoretical inlet pipe pressure being defined; and

fig. 6 shows a flowchart of a method for determining an adjustment quantity for adjusting an intake manifold pressure in an intake manifold in an internal combustion engine with a control circuit according to a second exemplary embodiment.

REFERENCE SIGNS LIST

1 drive device

10 air inlet pipe

11 air throttle

12 internal combustion engine

13 exhaust gas turbocharger

130 turbine

131 compressor

14 exhaust gas channel

2 Engine control System

20 regulating circuit for regulating the pressure in the intake pipe

3 conventional regulating circuit

30 intake pipe pressure sensor

31 interference amount observer

32P P Regulation

32I I Regulation

33 non-linear converter

34 regulating quantity limiter

35 scaling and adjusting unit

36a,36b,36c differentiators

Regulating circuit according to the first embodiment

40 reverse conversion device

41 theoretical quantity limiter

Method for correcting a set intake manifold pressure by means of a control circuit 4

50 maximum and minimum possible throttle opening area transitions

Definition of 51 theoretical intake pipe pressure

Regulating circuit according to a second embodiment

60 reverse conversion device

61 correction unit

Method for correcting the set intake manifold pressure by means of the control circuit 6

70 conversion of maximum and minimum possible throttle opening area

71 theoretical intake manifold pressure limit.

Detailed Description

Fig. 1 shows a section of a drive assembly 1. The drive assembly 1 has an intake pipe 10, a throttle valve 11, an internal combustion engine 12, an exhaust turbocharger 13, and an exhaust passage 14. A throttle valve 11 is arranged in the intake line 10 and is designed to regulate the delivery of fresh air into the internal combustion engine 12. The internal combustion engine 12 is connected with the intake pipe 10 and with the exhaust passage 14. The exhaust gas turbocharger 13 provided for adjusting the boost pressure in the intake pipe 10 has a turbine 130 and a compressor 131, which are connected with the turbine 130 via a shaft. The turbine 130 is disposed in the exhaust passage 14 and is driven by exhaust gas flowing out from the internal combustion engine 12. The compressor 131 is disposed in the air intake pipe 10 and compresses air in the air intake pipe 10 driven by the turbine 130.

The drive assembly 1 further comprises an engine control system 2 having a control circuit 20 for adjusting the intake manifold pressure in the intake manifold.

In conventional drives, the control circuit 20 is often designed as described with reference to fig. 2. Fig. 2 shows a control circuit 3 with an intake manifold pressure sensor 30, a disturbance variable observer 31, a PI controller (which includes a P controller 32P and an I controller 32I), a nonlinear converter 33, an adjustment variable limiter 34 and a scaling and adjustment unit 35.

The intake pipe pressure sensor 30 measures the current actual intake pipe pressureAnd will represent the actual intake pipe pressure detectedOf the measurement signalTo a first differentiator (sometimes referred to as a differentiator) 36a preceding the I conditioning 32I, to an interference quantity observer 31 preceding the first differentiator 36a, and to a second differentiator 36 b.

The disturbance variable observer 31 is provided for the intake pipe pressure based on the theoryAnd measuring the signalDetermining an estimated intake pipe pressure by means of a model describing the influence of a throttle on the intake pipe pressure and by means of an intake pipe pressure model. Here, the estimated intake pipe pressureIt is explained which actual intake pipe pressure will be adjusted.

A first differentiator 36a is formed in the measurement signalWith estimated intake pipe pressureAnd passes it to I regulation 32I. I adjust 32I to make the signal under measurementWith estimated intake pipe pressureThe difference between them is subjected to integral adjustment, and the result is obtainedTo the third differentiator 36c, thereafter to the second differentiator 36b and before the P-regulator 32P.

The second differentiator 36b is formed by the theoretical inlet pipe pressureAnd measuring the signalThe difference is formed and passed to a third differentiator 36 c. The third differentiator 36c forms the theoretical inlet manifold pressureAnd measuring the signalDifferences in composition and outcome of I modulationThe difference is made and the result is passed to P regulation 32P.

P adjustment 32P subjects the result of third differentiator 36c to a proportional adjustment and passes the result to a non-linear converter 33. It performs a nonlinear conversion in order to determine a theoretical throttle opening area and opens the theoretical throttleThe port area is given to the adjustment amount limiter 34. Maximum possible throttle opening area predetermined by the configuration of the throttle and the installation thereof into the intake manifoldAnd minimum possible throttle opening areaThe adjustment amount limiter 34 corrects the theoretical throttle opening area and transmits the corrected theoretical throttle opening area to the scaling and adjusting unit 35. The adjustment limiter 34 checks whether the theoretical throttle opening area is at the maximum possible throttle opening areaAnd minimum possible throttle opening areaAnd only if this is not the case, the theoretical throttle opening area is matched. The scaling and adjusting unit 35 calculates a throttle position from the corrected throttle opening area (defined throttle opening area) and adjusts the throttle position. Thereby adjusting the actual intake pipe pressure。

The control circuit 3 described with reference to fig. 2 has the disadvantage that the target intake manifold pressure is strived to reach a value at which the throttle opening area is greater than the maximum possible throttle opening area or less than the minimum possible throttle opening area, respectively, and regulation is not possible over a long period of time, as a result of which the I-component (saturation) is increased continuously. When the target intake pipe pressure is subsequently strived for another value, in which case the throttle opening area assumes a value between the maximum or minimum possible throttle opening area, a strong overshoot of the governor can result, since the high I part first has to be damped again as a result of the overshoot. The I regulation must therefore be frozen in the first-mentioned case, which entails costly reinitialization.

Two exemplary embodiments of the control circuit according to the invention are explained below on the basis of the control circuit 3 of fig. 2, which make freezing and thus also reinitialization of the I control superfluous and considerably simplifies the control of the intake manifold pressure.

Fig. 3 shows a first embodiment of a regulating circuit 4 according to the invention. In addition to the components of the regulating circuit 3 of fig. 2, the regulating circuit 4 comprises a reverse-switching device 40 and a theoretical quantity limiter 41. The inverse transformation device 40 is designed to take into account the measurement signalAnd I results from adjusting 32IWill maximize the possible throttle opening areaConversion to maximum achievable theoretical inlet manifold pressureAnd the smallest possible throttle opening areaConversion to the minimum achievable theoretical inlet manifold pressure. The theoretical quantity limiter 41 is configured for limiting the theoretical intake pipe pressure according to the maximum achievable theoretical intake pipe pressureAnd minimum achievable theoretical inlet pipe pressureCorrecting theoretical inlet manifold pressure. The theoretical limiter 41 here operates similarly to the adjustment limiter 34.

Fig. 4 shows a flowchart of a method 5 for correcting the set intake pipe pressure by means of the control circuit 4 of the first exemplary embodiment.

In the case of 50, the maximum possible throttle opening area is converted to the maximum achievable intake pipe pressure. This conversion is achieved based on the relationships already introduced above:

(1a)

or

(2a)。

In case 51, the maximum achievable intake pipe pressure is switchedAnd minimum achievable inlet pipe pressure convertedA theoretical intake manifold pressure is defined. The theoretical intake pipe pressure is checked by the theoretical quantity limiter 41Whether or not at the maximum achievable theoretical inlet manifold pressureAnd minimum achievable theoretical inlet pipe pressureAnd only if this is not the case is the theoretical intake pipe pressure matched。

By theoretical inlet manifold pressureThe defined correction prevents the target intake manifold pressure from reaching a value at which the throttle opening area exceeds the maximum possible throttle opening area or falls below the minimum possible throttle opening area, since for the adjustment of each corrected target intake manifold pressure there is an achievable throttle opening area or an achievable throttle position. The control loop can thus be regulated continuously and the freezing and reinitialization of the I control is rendered superfluous.

Fig. 5 shows a second embodiment of the regulating circuit 6 according to the invention. In addition to the components of the regulating circuit 3 of fig. 2, the regulating circuit 6 comprises a reverse switching device 60 and a correction unit 61. The reverse conversion device 60 is configured for use in a non-limiting throttle opening areaAnd a defined throttle opening areaThe difference therebetween is converted into a pressure difference. The correction unit 61 is designed as an adder which brings about a pressure differenceAnd theoretical intake pipe pressureAdding and giving the sum as a corrected theoretical intake pipe pressure。

Fig. 6 shows a flowchart of a method 7 for correcting the set intake pipe pressure by means of the control circuit 6 of the second exemplary embodiment.

In the case of 70, at an undefined throttle opening areaAnd a defined throttle opening areaForm a difference therebetweenAnd the difference is determined according to the relationship already mentioned aboveConversion to differential pressure。

(3a)

In the case of 71, a pressure difference is formedAnd theoretical intake pipe pressureThe sum of the components is used as the corrected theoretical intake pipe pressureIt is given.

The inverse transformation means 60 and the correction unit 61 form an algebraic loop together with the second and third differentiators, the P-regulating, non-linear transformer and the adjustment limiter. The algebraic ring can be unwrapped if desired, for example as a fixed-point iteration.

Again by theoretical inlet manifold pressureIs effective to prevent the theoretical intake pipe pressure from striving to reach a value in which the throttle opening area is greater than the maximum value, respectivelyThe possible throttle opening area is either less than the smallest possible throttle opening area. The control loop can thus be continuously regulated and the freezing and reinitialization of the I control is rendered superfluous.