KR101886907B1 - Method for operating an internal combustion engine and arithmetic unit - Google Patents

Abstract

The present invention relates to an open circuit control method for an internal combustion engine having two or more cylinders having two or more operating modes in which only the entire cylinders are ignited in the first operating mode and only a part of the cylinders are ignited in the second operating mode , The lambda sum actual value of the internal combustion engine is adjusted by the lambda closed loop controller to the desired lambda sum set value through matching of the amount of fuel and / or air supplied to the ignited cylinder, and at least the second operation for each ignited cylinder Mode, an individual correction coefficient for correction of the amount of fuel and / or air supplied to each cylinder is determined and stored so as to adjust the lambda individual actual value of each cylinder to the desired lambda individual set value, and from the first operation mode Upon switching to the second operating mode, the ignited cylinder is supplied with a stored individual correction factor.

Description

METHOD FOR OPERATING AN INTERNAL COMBUSTION ENGINE AND ARITHMETIC UNIT,

The present invention relates to a method of operating an internal combustion engine and an operating unit for its execution.

The air-fuel ratio is adjusted so that the average value of the lambda values of all the cylinders is "? = 1.0 " through the lambda closed loop control for the so-called uniform operation in the gasoline engine. As a result, it is possible to perform the exhaust gas saving operation by the conventional three-way catalytic converter which exhibits maximum efficiency at the time of stoichiometric combustion as is known.

Due to metering feed tolerances and cylinder-by-cylinder air / charge differences, for example due to system tolerances, lambda values in individual cylinders of the internal combustion engine may deviate from one another despite the same control. Thus, the lambda value, also referred to hereinafter as the lambda sum actual value, and the sum of the contributions of the individual cylinders, measured in the exhaust gas, can take a set value of 1.0, even though the lambda individual actual values fluctuate near this average value It is true.

(Lambda _{cylinder 1} = 1.1, lambda _{cylinder 2} = 0.9, lambda _{cylinder 3} = 1.2 and lambda _{cylinder 4} = 0.8) for the cylinders (cylinder 1 to cylinder 4) of the _four- The sum actual value (lambda _{cylinder 1 ... 4} = 1.0) is obtained. The corresponding deviation from the mean value of the individual cylinders (i. E., For individual cylinders, trimming) is referred to herein as the cylinder-free state.

The cylinder ratio compensation state has a series of disadvantages. Trimming cylinder lambda values directly leads to an increase in fuel consumption first. When trimming exceeds a certain limit value, the emotion deteriorates in some cases. In this case, it is furthermore important, for example, due to the different cylinder charge, the so-called bundle formation of the exhaust gas, i.e. the formation of the flow path in the exhaust gas mass flow. It is desirable to recognize this type of exhaust gas deterioration and / or make it adjustable through a suitable closed-loop control strategy, and is required in part by relevant laws.

From the prior art, different methods are known for the recognition or adjustment of the cylinder-free state of compensation in uniform operation.

On the other hand, the signal of the lambda sensor can be analyzed, and this signal is divided and evaluated into individual values for the cylinder. This is known, for example, from WO 96/35048 A1. However, the feasibility of such a method largely depends on the geometry of the exhaust gas branching device and presents a demanding requirement that can not often be met in the engine structure and the exhaust gas branching device structure.

On the other hand, the method based on the number of revolutions provides recognition of the injection quantity errors of the engine in the lean operation (> 1). In this case, the entire cylinders are simultaneously switched to the lean operation, and the cylinder-specific characteristics are evaluated as irregular operation. In contrast to the uniform operation, in the lean operation, the engine torque is linearly related to the injection amount. In order to ensure that the exhaust gas is not striking, and to obtain a sum lambda of lambda = 1.0, the further post-injection which does not act on the torque in this case is stopped. Therefore, this method is not suitable for a suction pipe engine. Corresponding methods and further embodiments are described, for example, in DE 195 27 218 A1, DE 43 19 677 A1, DE 10 2004 010 412 A1, DE 197 33 958 A1, EP 0 929 794 B1 and DE 10 2006 026 390 A1.

The whole method mentioned requires so-called full engine operation in which all the cylinders are ignited. However, today's engine concepts completely block the individual cylinders in the low partial load region for fuel savings, so that no further combustion takes place within them. This type of operation is also referred to as half engine operation or partial engine operation.

Therefore, optimal lambda adjustment of half engine operation or partial engine operation is also required.

Under these circumstances, the present invention proposes a method of operating an internal combustion engine having the features of the independent claim and an operation unit for its execution. Preferred embodiments are subject of the respective dependent claims and the following description.

The means presented in accordance with the invention operate in two or more operating modes and are used in the category of methods for operating an internal combustion engine with two or more cylinders. In this case, in the first operating mode, all the cylinders of the internal combustion engine are ignited to produce a corresponding engine torque, i.e. the fuel / air mixture is supplied in a normal engine operation, for example a four stroke operation, The auto-ignition method can be executed. In one or more additional operating modes, only a portion of the cylinder is ignited, and in some cases only one cylinder may be ignited.

In all operating modes, the lambda sum actual value of the internal combustion engine is adjusted by the lambda closed-loop controller to the lambda sum set value through the matching of the amount of fuel and / or air supplied as a whole to the ignited cylinder. This is called comprehensive lambda closed loop control and is well known in the prior art. As already partially discussed above, the lambda actual values provide a stoichiometric ratio, respectively, present in the internal combustion engine. Air mixture is "enriched ", i. E. The lambda value shifts to a value of < 1, and, conversely, through the reduction of the amount of fuel supplied, the fuel / Air mixture is "lean ", i. E. The lambda value can correspondingly vary in the range > 1.

As described above, for example, when there is a metering feed tolerance and cylinder-by-cylinder air / charge difference, each individual lambda actual value does not necessarily correspond to the lambda sum actual value. Thus, the lambda individual actual values may deviate from the lambda sum actual value that they form globally. Thus, besides comprehensive lambda closed loop control, cylinder lambda closed loop control is also provided. In the cylinder lambda closed loop control, for each ignited cylinder, the lambda individual actual value of each cylinder is also normally adjusted to the desired lambda individual set point, which is substantially &lt; RTI ID = 0.0 &gt; A correction coefficient for correcting the air amount is determined. In this case, if the individual cylinders have a lambda value of> 1, as described above, the corresponding fuel amount will rise correspondingly (and / or the air amount decreases) through the correction value. Conversely, if the cylinder lambda value is &lt; 1, the amount of fuel decreases (and / or the amount of air increases). As described above, there are different methods for determining the cylinder lambda deviations, for example, calculated through the characteristic values, and these characteristic values can be determined again by the irregular operation method.

Cylinder lambda closed loop control is preferably performed when the lambda sum actual value is adjusted to the lambda sum set value through the lambda closed loop controller of the internal combustion engine and the same fuel set amount is supplied to the cylinders, respectively. Under these conditions, the cylinder-specific deviation can be determined best. In this case, the fuel set amount does not necessarily correspond to the actual amount of fuel supplied, for example, when there is a variation in the injection behavior of the injection valve and the nozzle needle is filled. In this case, the contradiction between the set value and the actual value may be the source of the cylinder lambda deviation, but it is not necessarily the only source.

A change in the lambda sum actual value may occur through the pause of the individual cylinders upon switching from the first operating mode to the second operating mode if only partial engine operation in which only part of the cylinder is ignited, i. This is due to the fact that the correction coefficients in the typical cylinder lambda closed loop control are determined to be 100% on average (so that the resulting correction of the overall system is performed so that the lambda is not noticeable through the cylinder-specific matching value, It does not require variation of the actual value). Therefore, at the time of switching, it is usual that the correction coefficient of the cylinder to be held is not obtained at 100% and should be correspondingly tracked. No optimum exhaust gas conditions are presented during this time zone, which should be avoided. It can also cause undesirable intervention of a comprehensive lambda closed loop control.

Therefore, in accordance with the present invention, tracking is not necessary since it is provided to directly control the cylinder to be ignited with appropriate cylinder-dependent correction coefficients at the time of switching from the first operation mode (full engine operation) to the other operation mode . Suitable cylinder specific correction factors can be determined, for example, at an earlier transition (for example, in the category of the test operation mode) by waiting for the end of tracking and storing the resulting correction coefficients. This applies equally to the transition from partial engine operation to full engine operation with only minor modifications to the required parts.

The present invention realizes the preferred cylinder-by-cylinder open circuit control according to the switching state by appropriately pre-determining, storing, and immediately after switching the appropriate cylinder-dependent correction coefficients for different operating modes.

When switching to an operation mode in which the correction value is not yet stored, for example, the correction values or the correction values of the other operation modes are used, and the first tracking can be waited.

A control unit of an arithmetic unit, for example an automobile or engine system, according to the present invention is implemented, in particular by means of program technology, for carrying out the method according to the invention.

In particular, it is also desirable to implement the method according to the present invention in software form, especially since the control device being used is also used for other tasks and accordingly is somewhat less costly. Suitable storage media for the provision of computer programs are in particular diskettes, hard disks, flash memories, EEPROMs, CD-ROMs, DVDs, and the like. It is also possible to download programs via a computer network (Internet, intranet, etc.).

Additional advantages and embodiments of the present invention are set forth in the following description and attached drawings.

It is to be understood that the features mentioned above and to be described in more detail below are applicable not only to the respective combinations described but also to other combinations and also to individual ones without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated schematically in the drawings by way of example and will be described in detail below with reference to the drawings.

1 is a plan view showing an internal combustion engine in which the concept according to the present invention can be implemented.
2 is a side view showing an internal combustion engine in which the concept according to the present invention can be implemented.
FIG. 3 is a schematic flow chart showing a method according to a preferred embodiment of the present invention.

1 shows an internal combustion engine 10 having a fuel system 20, an air inflow system 30 and an exhaust gas system 40 and a control unit 50 for controlling the vehicle A part of which is schematically shown as a plan view. The internal combustion engine 10 is preferably formed as a fuel direct injection type gasoline engine. The internal combustion engine 10 includes four cylinders 11, 12, 13 and 14 in the illustrated embodiment, but a different number of cylinders is also possible. Fuel is provided through the fuel system 20 and is injected into the cylinders 11, 12, 13, 14 via corresponding injection valves 21, respectively.

The cylinders 11, 12, 13 and 14 are supplied with air through the air inflow system 30 and the inflow valves 31 are provided in the cylinders 11, 12, 13 and 14, respectively. The combustion exhaust gas is discharged from the cylinders 11, 12, 13, 14 through the discharge valve 41 and exhausted through the exhaust gas system 40. The exhaust system 40 is provided with a catalytic converter 42, which converts in particular carbon monoxide and nitrogen oxides, and is preferably formed as a three-way catalytic converter.

Control device 50 may be used to control the internal combustion engine 10, the fuel system 20, the air inflow system 30, and / or the exhaust system 40 in a suitable manner, do. In detail, the control device 50 controls, for example, the injection valve 21, the inlet valve 31, the discharge valve 41 and further control elements. In particular, the control device 50 is formed to provide the prescribed amount of fuel by the injection valve 21. [ The control device 50 may include a lambda closed-loop controller 52 formed as part of the controller 50. The control device 50 is installed to execute the method according to the present invention by a program technique.

In addition, suitable sensors, such as a lambda sensor 51 disposed upstream of the catalytic converter 42, in particular in the exhaust gas system 40, for measuring the corresponding engine condition, and a temperature sensor and / Since the sensors are provided, the operation of the internal combustion engine 10 can be realized by the control device 50 in accordance with such engine condition. The lambda sensor 51 is installed to measure the oxygen content in the exhaust system 40 and compares this oxygen content or a corresponding value derived therefrom to the lambda closed loop controller 52 implemented in the control device 50, .

The control device 50 controls the internal combustion engine by means of a control command O or by transmission of a corresponding parameter to provide a drive torque. To this end, the control device 50 obtains an input value I including an external requirement that allows the drive torque demand from the outside to be preset, for example, the driver's requested torque, the accelerator pedal position and the like. The control device 50 also receives from the above-described sensors the engine status as the input value I, for example, the corresponding values for the temperature, pressure and number of revolutions in the air supply system 20 and / Information.

All cylinders 11, 12, 13, 14 of the internal combustion engine 10 in the full engine operation are activated and ignited in a predetermined sequence according to a four stroke operation which is, for example, well known and not described in detail herein. do.

According to a desired operating state, for example a preset of the driver's requested torque, or depending on the operating state of the internal combustion engine 10 such as, for example, an idling operation, the control device 50 controls the cylinders 11, 12, &Lt; RTI ID = 0.0 &gt; and / or &lt; / RTI &gt; In this case, at least one of the cylinders 11, 12, 13, 14 is shut off and the total drive torque is limited to only one ignited cylinder 11, 12, 13, 14 or ignited cylinders 11, 13, 14). The corresponding partial cut is called partial engine operation. In this case, when half of the cylinders 11, 12, 13, 14 are shut off, it is called half engine operation. Half engine operation represents a standard of partial engine operation, because it places the least load on the mechanism of the internal combustion engine 10. In this case, switching from one set of cylinders 11, 12, 13, 14 to another set of cylinders 11, 12, 13, 14 may also be provided, The cylinders 11 and 13 are ignited and the cylinders 12 and 14 are ignited in the second operating mode.

In Fig. 2, a part of Fig. 1 is alternatively shown as a side view, and the members corresponding to Fig. 1 are not newly described for the sake of clarity. In this case, the illustration of the series of components, particularly the fuel system 20, the air inlet system 30, and the exhaust system 40, is omitted.

Each of the pistons 11 ', 12', 13 ', 14' is disposed in the cylinders 11, 12, 13, The combustion forces acting on the pistons 11 ', 12', 13 ', 14' upon ignition of the corresponding cylinders 11, 12, 13 and 14 are determined by the piston rods 11 ", 12" , 13 &quot;, 14 &quot;, respectively, to the crankshaft 15. The combustion forces acting on the pistons 11 ', 12', 13 ', 14' are changed when the above-mentioned cylinders are not compensated, for example when the fuel amount is different, The conformity of the rotational motion also changes. The corresponding non-conformance is called irregular operation.

The transmitter wheel 16 is non-rotatably engaged with the crankshaft 15 for determination of irregular operation. The rotational movement of the transmitter wheel 16 is indicated, for example, by the signal 53 'of the rotational angle sensor 53. The controller 50 or a correspondingly provided evaluation module 54 evaluates the signal 53 'and determines cylinder-dependent values therefrom.

The transmitter wheel 16, shown in side view in FIG. 2, has a landmark 16 'distributed over its periphery. Such a mark 16 'may be a ferromagnetic protrusion having an edge that forms an edge of a steep slope in the signal 53' when passing through an inductive sensor used as a rotational angle sensor 53, for example. The transmitter wheel 16 may be distributed into segments. Each segment may have a predetermined number of markings 16 '. Through counting of the signal edges, the control device 50 confirms the start and end of the corresponding segment, respectively, and determines the segment time that the segments go through the rotation angle sensor 53. [

In Figure 3, a method according to a particularly preferred embodiment of the present invention is schematically depicted, generally designated as "100 ". The illustrated method is divided into a matching step (left side) in which a correction value is first calculated and stored, and an operation step (right side) in which the correction value is processed.

In the first step 101, an internal combustion engine such as, for example, the internal combustion engine 10 of Figs. 1 and 2, operates in full engine operation. In this case, the lambda closed-loop controller continuously adjusts the lambda sum actual value of the internal combustion engine 10 to the lambda sum set value, for example, a value (1.0) for achieving uniform operation. For example, through a suitable method by an irregular operating method, cylinder lambda deviations are calculated and compensated respectively through the matching values corresponding to the lambda closed-loop control, that is, the individual lambda individual actual values of the individual cylinders are also set to lambda individual set values For example, a value of 1.0. The correction value for full engine operation is preferably stored in the control device 50 of the engine control system 1, for example as shown in Figures 1 and 2, as shown via arrow 101 ' .

At any point in time, a corresponding control signal 50 'requesting a different operating mode, for example partial engine operation or half engine operation, is obtained from the control device 50 (or the corresponding other open circuit control device). Next, the internal combustion engine is switched to a new operating mode and is operated in a new operating mode at step 102. [ A new cylinder lambda deviation is calculated and compensated through the overlaid correction values corresponding to the lambda closed loop control, respectively. The correction value for this operating mode is stored inside the control device 50 as shown via arrow 102 '.

Step 102 may be repeated for all desired operating modes. Then, cylinder-dependent correction values for all desired operating modes are stored in the control device 50. [

In method step 201, the internal combustion engine is newly operating in full engine operation. In this case, however, the correction value for full engine operation is read from the control device 50 as shown via arrow 201 '.

At any point in time, the control device 50 obtains a corresponding control signal 50 'that requires a different operating mode, for example partial engine operation or half engine operation. Next, the internal combustion engine is switched to the new operating mode, and the new operating mode is operated in step 202. [ Cylinder-specific correction values for this new operating mode are read out from the control device 50 as shown via arrow 202 '.

Thereafter, switching between the desired operating modes is carried out, corresponding to the switching between step 201 and step 202. [

For example, in the four-cylinder engine, when the set injection amount is 100%, the actual injection amount EM, that is, EM_cylinder_1 = 100%, EM Cylinder_2 = 100%, EM_cylinder_3 = 100%, and EM_cylinder_4 = 140%.

0.71 이며, 이로부터 약 0.93의 람다 합산 실제값이 얻어진다.The lambda individual actual values behave to be proportional to the injection quantity indirectly with sufficient accuracy, i.e., lambda_cylinder_l = 1, lambda_cylinder_2 = l, lambda_cylinder_3 = l, lambda_cylinder_4

0.71, from which an actual lambda sum value of about 0.93 is obtained.

93%, EM_실린더_2

93%, EM_실린더_3

93%, EM_실린더_4 = 130%으로 감소시킬 수 있을 것이다.A comprehensive lambda closed-loop control is used to achieve the lambda sum actual value of 1, the injection quantity through all the cylinders to EM_cylinder_l

93%, EM_cylinder_2

93%, EM_cylinder_3

93%, and EM_cylinder_4 = 130%.

1.08, λ_실린더_2

1.08, λ_실린더_3

1.08, λ_실린더_4

0.77이다.At this time, the individual actual value of the lambda with sufficient accuracy is about lambda_cylinder_l

1.08, lambda_cylinder_2

1.08, lambda_cylinder_3

1.08, lambda_cylinder_4

0.77.

1.08, FAK_실린더_2

1.08, FAK_실린더_3

1.08, FAK_실린더_4

0.77를 측정할 수 있을 것이다.The cylinder lambda closed loop control is carried out by the correction coefficient FAK by the average value = 1, that is, FAK_cylinder_l

1.08, FAK_cylinder_2

1.08, FAK_Cylinder_3

1.08, FAK_Cylinder_4

0.77. &Lt; / RTI &gt;

From this, in full engine operation, EM_cylinder_1 = 100%, EM_cylinder_2 = 100%, EM_cylinder_3 = 100%, EM_cylinder_4 = 100% will be obtained.

The actual injection amount EM, that is, the EM_cylinder_3 = 100% and the EM_cylinder_4 = 140% when the set injection amount is 100%, is obtained at half engine operation by the cylinders (cylinder_3 and cylinder_4) .

0.71 이며, 이로부터 약 0.86의 람다 합산 실제값이 얻어진다.The lambda individual actual values behave to be proportional to the injection quantity indirectly with sufficient accuracy, i.e., lambda_cylinder_3 = 1, lambda_cylinder_4

0.71, from which an actual lambda sum value of about 0.86 is obtained.

86%, EM_실린더_4 = 120%으로 감소시킬 수 있을 것이다.A comprehensive lambda closed-loop control can be used to achieve the lambda sum actual value of 1,

86%, EM_cylinder_4 = 120%.

1.16, λ_실린더_4

0.83이다.At this time, the individual actual value of the lambda with sufficient accuracy is about lambda_cylinder_3

1.16, lambda_cylinder_4

0.83.

1.16, FAK_실린더_4

0.83를 측정할 수 있을 것이다.The cylinder lambda closed loop control is performed by the correction coefficient (FAK) by the average value = 1, that is, FAK_cylinder_3

1.16, FAK_cylinder_4

0.83. &Lt; / RTI &gt;

This transition from full engine operation to half engine operation appears to require matched correction factors. In the scope of the present invention, it is unnecessary to newly determine the correction coefficient after the conversion. Instead, it is calculated, stored, and used if necessary.

Claims (10)

An operating method (100) of an internal combustion engine (10) having two or more cylinders (11-14) having two or more operating modes, wherein in the first operating mode all cylinders (11-14) In the operation mode, only a part of the cylinders 11 to 14 is ignited, and the lambda sum actual value of the internal combustion engine 10 is controlled by the lambda closed-loop controller 52 to the amount of fuel supplied to the ignited cylinders 11 to 14 And at least in the second operating mode for each ignited cylinder 11 to 14, the lambda individual actual values of the respective cylinders 11 to 14 are adjusted to the desired lambda addition set value through the matching of either or both of them, In order to adjust the value to the desired lambda individual set value, individual correction coefficients for correction of either or both of the amount of fuel and the amount of air supplied to each of the cylinders 11 to 14 are determined and stored, from Wherein the ignited cylinder is supplied with a stored individual correction coefficient at the time of switching to the second operating mode. 2. A method as claimed in claim 1, characterized in that in a first operating mode for each ignited cylinder (11-14), in order to adjust the lambda individual actual value of each cylinder (11-14) to the desired lambda individual setpoint, The individual correction coefficients for correction of either or both of the amount of fuel and the amount of air supplied to the cylinders 11 to 14 are determined and stored, and upon switching to the first operating mode, Receiving, operating the internal combustion engine. 3. The method according to claim 1 or 2, wherein the individual correction coefficient is determined in the category of cylinder lambda closed loop control. 3. The method according to claim 1 or 2, wherein the individual correction coefficient is determined by switching the internal combustion engine (10) from the first operation mode to the second operation mode and determining the variation of the resulting lambda actual value caused thereby , A method of operating an internal combustion engine. 3. A method (100) for operating an internal combustion engine as set forth in claim 1 or 2, wherein said individual correction coefficient is determined through determination of an irregular operation of the internal combustion engine (10). 6. Method according to claim 5, characterized in that the irregular operation is determined by a sensor arrangement (16, 53) which produces a revolution number signal (53 ') indicative of the revolution number of the internal combustion engine (10) . 7. The method according to claim 6, wherein the sensor device (16, 53) comprises a transmitter wheel (16) mounted on the crankshaft of the internal combustion engine (10) and scanned by a sensor (53) . 3. A method (100) for operating an internal combustion engine as set forth in claim 1 or 2, wherein the internal combustion engine (10) is operated in a first operating mode or a second operating mode depending on the load. 9. The method of operating an internal combustion engine (100) according to claim 8, wherein the second operating mode comprises half engine operation wherein exactly half of the cylinders (11-14) of the internal combustion engine (10) are not ignited. An operational unit, installed for the execution of the method according to claim 1 or 2.

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