DE102006024005B3 - Speed control for an internal combustion motor, using a throttle flap at the air intake, sets a dynamic air pressure nominal value according to the relationship between start and end nominal values - Google Patents

Abstract

To the Operating an internal combustion engine is based on a start setpoint (MAP_ST_SP) an intake manifold pressure a final setpoint (MAP_EN_SP) of the intake manifold pressure determined, depending on a predetermined setpoint of a torque request. Further is a dynamic setpoint (MAP_DYN_SP) of the intake manifold pressure so determines that the dynamic setpoint (MAP_DYN_SP) of the intake manifold pressure is lower is the final target value (MAP_EN_SP) of the intake manifold pressure, if the Starting setpoint (MAP_ST_SP) of the intake manifold pressure is greater than the final setpoint (MAP_EN_SP) of the intake manifold pressure. If the start setpoint (MAP_ST_SP) of the Intake manifold pressure is less than the final nominal value (MAP_EN_SP) of the intake manifold pressure, the dynamic setpoint value (MAP_DYN_SP) of the intake manifold pressure is so determines that the dynamic setpoint (MAP_DYN_SP) of the intake manifold pressure is larger as the final setpoint (MAP_EN_SP) of the intake manifold pressure. An opening degree the throttle valve (5) is dependent on the dynamic setpoint (MAP_DYN_SP) the intake manifold pressure is adjusted until a difference (MAP_DIF) between a measured value (MAP_MES) and the final setpoint (MAP_EN_SP) of the intake manifold pressure is less than a predetermined threshold.

Description

The The invention relates to a method and an apparatus for operating an internal combustion engine. The internal combustion engine comprises an intake tract. The intake tract comprises a suction tube. The intake system communicates dependent from the switching position of a gas inlet valve with a combustion chamber of a Cylinder of the internal combustion engine. In the intake tract is a throttle arranged, through which an air mass flow can be throttled into the suction pipe. To operate the internal combustion engine, starting from a start setpoint der Saugrohrdrucks a final setpoint of the intake manifold pressure determined depending on a predetermined setpoint of a torque request.

at fill-controlled Internal combustion engine, a load of the internal combustion engine preferably via an opening degree set a throttle valve of the internal combustion engine. The opening degree the throttle valve affects an air mass flow in the intake manifold out. Due to the air mass flow air mass is conveyed into the intake manifold, the then causes a Saugrohrdruck in the intake manifold. If it is a torque request to the engine changes abruptly, so The new torque request is made by a sudden adjustment the degree of opening implemented the throttle. However, because the actuator for adjusting the degree of opening the throttle only reacts with a delay and that too fill of the suction pipe a dependent from an operating condition of the internal combustion engine predetermined period of time needed can the torque request at the earliest after the delay and the period of time to be implemented.

From the DE 100 46 449 A1 is a method for adjusting an intake manifold pressure or a mass delivery of an internal combustion engine known. In a necessary change in the intake manifold pressure during operation of the internal combustion engine, the change in the position of the throttle valve is increased by such an amount and for such a period that is sucked by the increase in the position of the throttle an air mass that corresponds at least approximately to the air mass, which is needed to adjust the engine to the new load condition.

From the US 5,611,309 A is known a control system for a throttle valve of an internal combustion engine. When controlling the throttle, a period of time is taken, which elapses after an adjustment of the throttle, until an intake manifold pressure is adjusted in an intake tract of the internal combustion engine downstream of the throttle, which is to be adjusted by adjusting the throttle.

It The object of the invention is a method and a device for Operate an internal combustion engine to create that to a precise setting a dynamic setpoint of a intake manifold pressure of the internal combustion engine contribute.

The Task is solved by the characteristics of the independent Claims. Advantageous embodiments of the invention are specified in the subclaims.

The Invention is characterized by a method and an apparatus for operating an internal combustion engine. The internal combustion engine comprises an intake tract. The intake tract comprises a suction tube. Depending on the switching position of a gas inlet valve communicates the intake with a combustion chamber of a cylinder of the internal combustion engine. A Throttle valve is arranged in the intake tract, through which an air mass flow can be throttled in the intake manifold. To operate the internal combustion engine starts from a start setpoint of an intake manifold pressure Final setpoint of the intake manifold pressure determined depending on a given Setpoint of the torque request. If the starting setpoint of the Intake manifold pressure is greater than the final setpoint of the intake manifold pressure, becomes a dynamic setpoint of the intake manifold pressure determined so that the dynamic setpoint of Intake manifold pressure is less than the final setpoint of the intake manifold pressure. If the start setpoint of the intake manifold pressure is less than the final setpoint of the intake manifold pressure, becomes the dynamic setpoint of intake manifold pressure determined so that the dynamic setpoint of the intake manifold pressure is greater as the final setpoint of the intake manifold pressure. Furthermore, the dynamic Setpoint of intake manifold pressure dependent determined by a correction value of the intake manifold pressure. The correction value of the intake manifold pressure is determined depending on a dynamic Air mass with which the intake manifold must be additionally filled to the setpoint set the predetermined torque request, and depending on a delay time constant the throttle. An opening degree the throttle valve is dependent on the dynamic setpoint the intake manifold pressure adjusted until a difference between a Measured value and the final setpoint of the intake manifold pressure is less than a predetermined threshold.

Adjusting the smaller or larger intake manifold pressure, beyond the intake manifold pressure required to implement the torque demand, helps to quickly adjust the final setpoint of the intake manifold pressure. This contributes to a rapid implementation of Drehmomentanforde tion and thus to a precise operation of the internal combustion engine. Furthermore, determining the dynamic setpoint of the intake manifold pressure depending on the delay time constant of the Throttle valve to set the dynamic setpoint of the intake manifold pressure very precisely. The deceleration constant represents the deceleration by a throttle response and / or an actuator for adjusting the throttle.

In an advantageous embodiment of the method is the dynamic Air mass depends on the final setpoint and dependent determined from the measured value of the intake manifold pressure. This allows that adjusting the dynamic setpoint of intake manifold pressure itself especially affects the intake manifold pressure when a difference between the final setpoint and the measured value of the intake manifold pressure is large.

In a further advantageous embodiment of the method is the Correction value of the intake manifold pressure depending on a filling time constant of the Suction tube determined. The filling time constant represents the time required is to fill the intake manifold with the dynamic air mass.

The advantageous embodiments of the method can be advantageously on Embodiments of the device transferred become.

The The invention is described below with reference to schematic drawings explained in more detail.

It demonstrate:

1 an internal combustion engine,

2 a pressure-time diagram,

3 a control loop,

4 a first segment of a regulator of the control loop,

5 a second segment of the regulator.

elements same construction or function become cross-figurative marked with the same reference numerals.

An internal combustion engine ( 1 ) comprises an intake tract 1 , an engine block 2 , a cylinder head 3 and an exhaust tract 4 , The intake tract 1 preferably includes a throttle 5 , a collector 6 and a suction tube 7 that's going to
a cylinder Z1-Z4 via an inlet channel into a combustion chamber 9 of the engine block 2 is guided. The engine block 2 includes a crankshaft 8th , which has a connecting rod 10 with the piston 11 of the cylinder Z1-Z4 is coupled. The internal combustion engine is preferably a charge-controlled internal combustion engine, preferably an Otto internal combustion engine, and is preferably arranged in a motor vehicle.

The cylinder head 3 includes a valvetrain with at least one gas inlet valve 12 , at least one gas outlet valve 13 and valve actuators 14 . 15 , The cylinder head 3 further comprises an injection valve 22 and a spark plug 23 , Alternatively, the injection valve 22 also in the intake manifold 7 be arranged.

The exhaust tract 4 includes an exhaust gas catalyst 24 , which is preferably designed as a three-way catalyst.

A control device 25 is provided, the sensors are assigned, which detect different parameters and each determine the value of the measured variable. Operating variables include the measured variables and variables derived therefrom of the internal combustion engine and define an operating state of the internal combustion engine. The control device 25 determined depending on at least one of the operating variables at least one manipulated variable, which are then converted into one or more control signals for controlling the actuators by means of appropriate actuators. The control device 25 may also be referred to as a device for operating the internal combustion engine.

The sensors are a pedal position transmitter 26 , the accelerator pedal position of an accelerator pedal 27 detected, an air mass sensor 28 , the air mass flow upstream of the throttle 5 detected, a throttle position sensor 30 , the throttle opening degree 5 detected, a temperature sensor 32 sensing an intake air temperature, an intake manifold pressure sensor 34 that produces a manifold pressure in the collector 6 detected, a crankshaft angle sensor 36 which detects a crankshaft angle, which is then assigned a speed N. Depending on the embodiment of the invention, any subset of said sensors may be present, or additional sensors may be present.

The actuators are, for example, the throttle 5 , the gas inlet and outlet valves 12 . 13 , the injection valve 22 and / or the spark plug 23 ,

Next the cylinder Z1-Z4 are preferably further cylinders Z1-Z4 provided corresponding to those Actuators are assigned.

In the charge-controlled internal combustion engine, a load of the internal combustion engine is preferably via an opening degree of the throttle valve 5 set. The opening degree of the throttle valve 5 affects the air mass flow in the intake manifold 7 out. The air mass flow into the intake manifold 7 conveys an air mass into the intake manifold 7 in the suction tube 7 causes the intake manifold pressure.

Now changes a torque request to the internal combustion engine, which is requested for example by a driver of the motor vehicle and / or by the control device 25 is requested due to further vehicle functions, this torque request is implemented by a Saugrohrdruckanforderung. If, for example, the internal combustion engine is in an operating state in which a starting desired value MAP_ST_SP of the intake manifold pressure is set, and if an end nominal value MAP_EN_SP of the intake manifold pressure is requested by the changed torque request, the result is a pressure / time diagram ( 2 ), a jump from the starting target value MAP_ST_SP of the intake manifold pressure to the final target value MAP_EN_SP of the intake manifold pressure.

An actuator to control the throttle 5 and the throttle 5 respond only with a delay to the changed Saugrohrdruckanforderung. Furthermore, it takes a predetermined time until the intake manifold 7 filled with the air mass. Especially at very low speeds N, for example, at idle, and / or at a suction pipe 7 with a very large volume VOL_IM of the intake manifold 7 ( 4 ), the deceleration and the time period may adversely affect engine responsiveness and contribute to imprecise operation of the internal combustion engine.

In order to the final target value MAP_EN_SP of the intake manifold pressure preferably as possible is set quickly and thus the internal combustion engine operated precisely is, a correction value of the intake manifold pressure is preferably determined and added to the amount of the final setpoint MAP_EN_SP of the intake manifold pressure, so that thereby a dynamic setpoint MAP_DYN_SP of the intake manifold pressure is determined.

A rising edge in the course of the dynamic setpoint MAP_DYN_SP of the intake manifold pressure in the pressure-time diagram and a descending edge of the dynamic setpoint MAP_DYN_SP of the intake manifold pressure are due to the delays of the actuator or the throttle valve 5 and by the time for filling the suction tube 7 specified. A trapezoidal area, which is enclosed by the intake manifold pressure dynamic setpoint MAP_DYN_SP and the intake manifold pressure setpoint final MAP_EN_SP, is representative of a dynamic air mass MA_DYN with which the intake manifold 7 must be additionally filled to set the final setpoint MAP_EN_SP the intake manifold pressure.

Changes the torque request such that the final setpoint MAP_EN_SP of the Intake manifold pressure is less than the start setpoint MAP_ST_SP of the intake manifold pressure, thus, the correction value of the intake pipe pressure becomes from the final target value MAP_EN_SP withdrawn from the intake manifold pressure. The calculation of the dynamic Air mass MA_DYN then takes place as explained above.

The control device preferably comprises 25 a control loop ( 3 ) for regulating the intake manifold pressure. The control loop comprises blocks B1 to B5. Block B1 is representative of a regulator of the control loop. In a summing point A1 of the control loop, a difference MAP_DIF between a measured value MAP_MES of the intake manifold pressure and a starting target value MAP_ST-SP of the intake manifold pressure or a final target value MAP_EN_SP of the intake manifold pressure is determined. The difference MAP_DIF of the intake manifold pressure is the control deviation of the control loop. The starting nominal value MAP_ST_SP of the intake manifold pressure and the final nominal value MAP_EN_SP of the intake manifold pressure are the reference variables of the control circuit. As an output signal, the controller supplies a control signal for the throttle valve 5 represented by block B2.

In a point of addition A2, an air mass flow coming out of the intake manifold 7 into the combustion chamber 9 flows, introduced as a disturbance in the control loop.

A block B4 represents the suction pipe 7 , which is the controlled system of the control loop.

The measured value MAP_MES of the intake manifold pressure is detected in the block B5, which is representative of the intake manifold pressure sensor 34 ,

In A branch A3 becomes the measured value MAP_MES of the intake manifold pressure the addition point A1 returned.

A first segment of the controller according to 3 is represented by blocks B6 to B14 ( 4 ). In the block B6, a temperature TIA_IM in the suction pipe 7 determined. The temperature TIA_IM can be determined, for example, depending on the intake air temperature using a temperature characteristic map. The temperature characteristic map and optionally further maps are preferably recorded on a motor test bench and preferably on a storage medium of the control device 25 stored.

In a block B7, a volume VOL_IM of the intake manifold becomes 7 determined. The volume VOL_IM of the intake manifold 7 can be a given constant. The volume VOL_IM of the intake manifold 7 but can also be varied and by several entspre constant constants are represented.

In a block B8, a gas constant NC_RA is obtained from a storage medium of the control device 25 accessed. The gas constant NC_RA is preferably the specific or the specific gas constant.

In a block B9, the temperature TIA_IM of the intake manifold 7 , the volume VOL_IM of the intake manifold 7 and the gas constant NC_RA offset against each other, preferably under the calculation rule given in block B9. The output signal of block B9 represents the actual boundary conditions in the intake manifold pressure which must be taken into account in order to determine with which dynamic air mass MA_DYN the intake manifold 7 must be additionally filled to set the final setpoint MAP_EN_SP of the intake manifold pressure.

In A block B10 becomes a pressure quotient PQ dependent on the measured value MAP_MES the intake manifold pressure and dependent determined by an ambient pressure AMP. If the measured value MAP_MES of the intake manifold pressure is less than a minimum value of intake manifold pressure, is used to determine the pressure quotient PQ, preferably instead of the measured value MAP_MES of the intake manifold pressure the minimum value of intake manifold pressure used.

In a block B11, the rotational speed N is determined.

Of the Pressure quotient PQ and the speed N are the input variables to a Factor map represented by block B12. The output signal of block B12 is a factor between zero and one that depends on the engine load, by the pressure quotient PQ and the speed N is characterized by varying the impact of the dynamic Air mass MA_DYN allows.

A block B13 is representative of the addition point A1 ( 3 ). The output values of blocks B9, B12 and B13 are calculated in a block B14, preferably under the calculation rule given in block B14. The output of block B14 is a dynamic setpoint MA_DYN_SP of dynamic air mass MA_DYN.

Starting from the dynamic setpoint MA_DYN_SP of the dynamic air mass MA_DYN, the dynamic setpoint MAP_DYN_SP of the intake manifold pressure is determined in a second segment of the controller ( 5 ). For this purpose, first a time derivative of a difference between a value of the ambient pressure AMP and the final setpoint MAP_EN_SP of the intake manifold pressure. From this time derivation, a desired value MAF_KGH_DYN_SP of a mass air flow into the intake manifold can be derived via a derivative of the intake manifold pressure according to the air mass 7 be determined. The desired value MAF_KGH_DYN_SP of the air mass flow is limited depending on the operating state of the internal combustion engine by operating variables, for example by Saugrohrdruckanstiegszeitkonstanten and / or Saugrohrdruckabklingzeitkonstanten. Dependent on the setpoint MAF_KGH_DYN_SP of the air mass flow into the intake manifold 7 can be determined via a preferably linear motor flow rate function of the dynamic setpoint MAP_DYN_SP the intake manifold pressure. The linear motor throughput function is defined by a slope SLOP and a Y-axis section OFS represented by blocks 15 and B16, respectively.

In a block B17 and in a block B18, depending on the slope SLOP of the engine flow rate function and the Y-axis portion of the engine flow rate function and the target value MAF_KGH_DYN_SP of the air mass flow into the intake manifold 7 the dynamic setpoint MAP_DYN_SP of the intake manifold pressure is determined.

The invention is not limited to the specified embodiments. For example, the control loop outside the control device 25 be arranged. Furthermore, the control loop and / or segments of the control loop may be a software product.

1

intake system

2

block

3

cylinder head

4

exhaust tract

5

throttle

6

collector

7

suction tube

8th

crankshaft

9

combustion chamber

10

connecting rod

11

piston

12

Gas inlet valve

13

gas outlet

14 15

valve actuators

22

Injector

23

spark plug

24

catalytic converter

25

control device

26

Pedal position sensor

27

accelerator

28

Air mass sensor

30

Throttle position sensor

32

temperature sensor

34

intake manifold pressure sensor

36

Crank angle sensor

Z1-Z4

cylinder one to four

MAP_ST_SP

Start Setpoint Intake manifold pressure

MAP_EN_SP

final setpoint Intake manifold pressure

MAP_DIF

difference Intake manifold pressure

MAP_MES

reading Intake manifold pressure

AMP

ambient pressure

MAP_DYN_SP

dynamic Setpoint intake manifold pressure

MA_DYN

air mass

TIA_IM

temperature suction tube

VOL_IM

volume suction tube

NC_RA

constant

PQ

quotient MAP / AMP

N

rotation speed

SLOP

pitch

OFS

Y-axis section

MAF_KGH_DYN_SP

setpoint Air mass flow

B1-B18

Blocks one to eighteen

Claims (4)

Method for operating an internal combustion engine, which - an intake tract ( 1 ), which is a suction tube ( 7 ) and which depends on the switching position of a gas inlet valve ( 12 ) with a combustion chamber ( 9 ) of a cylinder (Z1-Z4) of the internal combustion engine, and - a throttle valve ( 5 ) located in the intake tract ( 1 ) is arranged and by the air mass flow into the suction pipe ( 7 ), in which, based on a starting setpoint value (MAP_ST_SP) of an intake manifold pressure, a final setpoint value (MAP_EN_SP) of the intake manifold pressure is determined as a function of a predefined setpoint value of a torque request and wherein - a dynamic nominal value (MAP_DYN_SP) of the intake manifold pressure is determined such that the intake manifold pressure dynamic setpoint (MAP_DYN_SP) is less than the intake manifold intake target pressure (MAP_ST_SP), if the intake manifold intake setpoint (MAP_ST_SP) is greater than the intake manifold manifold setpoint (MAP_EN_SP), then the intake manifold pressure dynamic setpoint (MAP_DYN_SP) is determined in that the intake manifold pressure dynamic setpoint (MAP_DYN_SP) is greater than the intake manifold pressure setpoint (MAP_ST_SP), if the intake manifold pressure start setpoint (MAP_ST_SP) is less than the intake manifold pressure (MAP_EN_SP) target pressure, - the intake manifold pressure dynamic setpoint (MAP_DYN_SP) from a correction value of Saugroh which is determined as a function of a dynamic air mass (MA_DYN) with which the intake manifold ( 7 ) must be additionally filled in order to set the setpoint value of the predetermined torque request, and which depends on a delay time constant of the throttle valve ( 5 ), which is a delay due to throttle response ( 5 ), and - an opening degree of the throttle valve ( 5 ) is adjusted as a function of the intake manifold pressure dynamic setpoint (MAP_DYN_SP) until the difference (MAP_DIF) between a measured value (MAP_MES) and the intake manifold pressure end setpoint (MAP_EN_SP) is less than a predetermined threshold value. The method of claim 1, wherein the dynamic Air mass (MA_DYN) dependent from the final target value (MAP_EN_SP) and depending on the measured value (MAP_MES) of the intake manifold pressure is determined. Method according to one of the preceding claims, in which the correction value of the intake manifold pressure is dependent on a filling time constant of the intake manifold ( 7 ) is determined. Device for operating an internal combustion engine comprising - an intake tract ( 1 ), which is a suction tube ( 7 ) and which depends on the switching position of a gas inlet valve ( 12 ) with a combustion chamber ( 9 ) of a cylinder (Z1-Z4) of the internal combustion engine communicates, - a throttle valve ( 5 ) located in the intake tract ( 1 ) is arranged and by the air mass flow into the suction pipe ( 7 ), wherein the device is designed starting from a start setpoint value (MAP_ST_SP) of an intake manifold pressure for determining a final setpoint value (MAP_EN_SP) of the intake manifold pressure as a function of a predefined setpoint value of a torque request and wherein the device is configured with means for - determining a dynamic setpoint value (MAP_DYN_SP ) of the intake manifold pressure such that the intake manifold pressure dynamic setpoint (MAP_DYN_SP) is less than the intake manifold pressure target setpoint (MAP_ST_SP) intake manifold pressure greater than the intake manifold pressure setpoint (MAP_EN_SP), Intake manifold pressure dynamic setpoint (MAP_DYN_SP) such that intake manifold pressure dynamic setpoint (MAP_DYN_SP) is greater than intake manifold pressure setpoint (MAP_EN_SP), if intake manifold pressure start setpoint (MAP_ST_SP) is less than intake manifold pressure setpoint (MAP_EN_SP) , - Determining the dyn amic setpoint (MAP_DYN_SP) of the intake manifold pressure dependent on a correction value of the intake manifold pressure which depends on a dynamic air mass (MA_DYN) determined with which the suction tube ( 7 ) must be additionally filled in order to set the setpoint value of the predetermined torque request, and which depends on a delay time constant of the throttle valve ( 5 ), which is a delay due to throttle response ( 5 ), and for - adjusting the throttle valve ( 5 ) depending on the intake manifold pressure dynamic setpoint (MAP_DYN_SP) until the difference (MAP_DIF) between a measured value (MAP_MES) and the intake manifold pressure end setpoint (MAP_EN_SP) is less than a predetermined threshold.