DE19923299A1 - Procedure for control of IC engine that comprises devices which influence exhaust of engine has with existence of certain conditions, special operating state introduced in which increased energy content of exhaust is desired. - Google Patents

Abstract

A procedure for the control of an IC engine that comprises devices which influence the exhaust of the engine, is described. With the existence of certain conditions, a special operating state is introduced in which an increased energy content of the exhaust is desired. In the special operating state, a combustion key point is influenced so that the exhaust temperature increases. The combustion key point is displaced in the direction of retardation. In the special operating state, at least one first and a second pre-injection takes place before a main injection. With the devices which influence the exhaust, a supercharger, a particle filter or a catalyser is meant.

Description

State of the art

The invention relates to a method and a device to control an internal combustion engine.

From the not previously published DE 199 06 287 are a Method and device for controlling a burner engine known. In the system described there a particle filter is used, the contained in the exhaust gas Filters out particles. In certain operating conditions the Particle filter regenerated by suitable measures. For Regeneration, the exhaust gas temperature must be increased. Be drive states with increased exhaust gas temperature have in the Re gel results in increased fuel consumption.

Furthermore, methods and a device for controlling egg ner internal combustion engine known. For those of a loader the energy contained in the exhaust gas to compress the air, which is fed to the internal combustion engine. Such La who have certain operating conditions, for example delayed response at low speeds.

Object of the invention

The object of the invention is based on a method and a device for controlling an internal combustion engine a method and a with an exhaust gas aftertreatment system Provide device with which the particle filter ver regenerated conveniently and / or the behavior of a La which can be improved.

This task is accomplished by the in the independent claims marked features solved.

Advantages of the invention

With the procedure according to the invention is an advantage adherent regeneration of the particle filter and / or a verb loader behavior possible. This will be there achieved by that the focus of combustion be so is influenced that the exhaust gas temperature and / or Exhaust gas energy content increased.

It is particularly advantageous if the burn severity point is moved late. The negative out effects on the combustion are avoided in that before the injection at least two pilot injections consequences.

Further particularly advantageous configurations are in the Subclaims marked.

drawing

The invention is explained below with reference to the embodiments shown in the drawing. In the drawings Fig. 1 is a block diagram of the apparatus according to the invention, Fig. 2 is a time course of the drive signal AD for fuel metering, Fig. 3 is a block diagram of a portion of the device and FIG. 4 is a flow chart of the inventive method.

Description of exemplary embodiments

In the following, the device according to the invention is shown at shown a self-igniting internal combustion engine, in which the fuel metering by means of a so-called Common rail system is controlled. The invention The procedure is not limited to these systems. It can also be used in other internal combustion engines become.

With 100 an internal combustion engine is referred to, which is supplied with fresh air via egg ne intake line 102 and gives off exhaust gases via an exhaust line 104 . An exhaust gas aftertreatment means 110 is arranged in the exhaust gas line 104 , from which the cleaned exhaust gases reach the surroundings via the line 106 . The exhaust gas aftertreatment means 110 essentially comprises a so-called pre-catalyst 112 and a filter 114 downstream. A temperature sensor 124 , which provides a temperature signal T, is preferably arranged between the precatalyst 112 and the filter 114 . Before the pre-catalyst 112 and after the filter 114 Sen sensors 120 a and 120 b are provided. These sensors act as differential pressure sensor 120 and provide a differential pressure signal DP that characterizes the differential pressure between the inlet and outlet of the exhaust gas aftertreatment agent.

In the exhaust gas line 104 , a turbine 162 is arranged which drives a compressor in the intake line 102 via a shaft 164 .

The internal combustion engine 100 is metered to fuel via a fuel metering unit 140 . This measures via injectors 141 , 142 , 143 and 144 to the individual cylinders of the internal combustion engine 100 fuel. The fuel metering unit is preferably a so-called common rail system. A high pressure fuel pump delivers fuel to a pressure accumulator. The fuel reaches the internal combustion engine via the injectors.

Various sensors 151 are arranged on the fuel metering unit 140 , which provide signals that characterize the state of the fuel metering unit. A common rail system is, for example, the pressure P in the pressure accumulator. Sensors 152 , which characterize the state of the internal combustion engine, are arranged on the internal combustion engine 100 . This is preferably a speed sensor that provides a speed signal N and other sensors that are not shown.

The output signals of these sensors arrive at a control 130 , which is shown as a first partial control 132 and a second partial control 134 . Preferably, the two partial controls form a structural unit. The first sub-controller 132 preferably controls the fuel metering unit 140 with control signals AD, which influence the fuel metering. For this purpose, the first partial control 132 includes a fuel quantity control 136 . This delivers a signal ME that characterizes the quantity to be injected to the second sub-controller 134 .

The internal combustion engine is equipped with means that Affect exhaust gas. This is in the darge presented embodiments around a loader and / or Particle filter. In addition to these, other means can also be considered  be seen that affect the exhaust gas. Such means of Exhaust gas treatment are, for example, catalysts.

The second partial control 134 preferably controls the exhaust gas aftertreatment system and detects the corresponding sensor signals for this purpose. Furthermore, the second sub-controller 134 exchanges signals, in particular via the injected fuel quantity ME, with the first sub-controller 132 . Preferably, the two controls mutually use the sensor signals and the internal signals.

The first partial control, which is also referred to as engine control 132 , controls depending on various signals that characterize the operating state of internal combustion engine 100 , the state of fuel metering unit 140 and the ambient condition, as well as a signal that indicates the power desired by the internal combustion engine and / or torque characterizes the drive signal AD for driving the fuel metering unit 140 . Such facilities are known and used in many ways.

Particle emissions can occur in the exhaust gas, especially in diesel engines. For this purpose, it is provided that the exhaust gas aftertreatment means 110 filter them out of the exhaust gas. Through this filtering process, 114 particles collect in the filter. These particles are then burned in certain operating states and / or after certain times to clean the filter. For this purpose, it is provided that the temperature in the exhaust gas aftertreatment agent 110 is increased so that the particles burn to regenerate the filter 114 .

In internal combustion engines, catalysts are often used as Ab gas treatment agent used. In particular so-called DENOX catalysts have to be regenerated at certain intervals  become. This means through an increased exhaust gas temperature deposits, especially sulfur and / or welding field connections, eliminated.

In the case of particle filters, the precatalyst 112 is provided for increasing the temperature. The temperature increase occurs for example in that the proportion of unburned carbons in the exhaust gas is increased. This unburned carbon dioxide then reacts in the pre-catalytic converter 112 , thereby increasing its temperature and thus also the temperature of the exhaust gas that enters the filter 114 .

This temperature increase of the pre-catalyst and the exhaust gas temperature requires increased fuel consumption and should therefore only be carried out when this is necessary, ie the filter 114 is loaded with a certain proportion of particles. One possibility of recognizing the loading condition is to detect the differential pressure DP between the inlet and outlet of the exhaust gas aftertreatment agent and to determine the loading condition based on this. This requires a differential pressure sensor 120 .

The size B, which determines the loading state of the filter 114, is determined by means of various sensors. The size B for the loading condition is then used to control the exhaust gas after-treatment system, that is, depending on the loading condition, a special operating condition is then initiated, which is also referred to below as regeneration.

In Fig. 1, the device is shown with a charger and an exhaust gas aftertreatment means 100 which summarizes a particle filter 114 . The procedure according to the invention can also be used in systems which are only equipped with a charger or only with an exhaust gas aftertreatment agent.

According to the invention, the regeneration is initiated and / or supports that the exhaust gas temperature is increased. There is a shift to increase the exhaust gas temperature of the center of combustion towards late. This means tet that a substantial part of the injection only after top dead center takes place. With a late injection worsened exhaust emissions nen. This is counteracted by the fact that before the egg general main injection at least two pre-injections tongues take place.

According to the invention, the exhaust gas temperature is increased in an internal combustion engine equipped with a charger in the presence of special operating conditions. At internal combustion machine with a loader, the following problem may occur. With small loads, i.e. small injection quantities, and / or low speeds an acceleration of the burning desired engine, the loader only reacts with egg ner a certain time delay, because he is in this Be drive state only little energy available for compression gung has. According to the invention it is provided that such loading operating states are regarded as a special operating state, where measures are taken to increase the exhaust gas temperature be directed.

In FIG. 2, the waveforms of the drive signal A is applied for one of the injectors 141 to 144 over time. The conditions in normal operation are plotted in sub-figure 2a. The main injection HE, in which the substantial proportion of fuel of the internal combustion engine is metered, takes place in the area of the top dead center OT. A first pre-injection VE1 takes place before the main injection HE. This is used to condition the combustion chamber. Pre-injection can significantly reduce emissions, especially sound emissions. To further improve combustion, a second pilot injection VE2 can be provided, which is shown in dashed lines. The two pre-injections occur well before top dead center.

In sub-figure 2b, the conditions are when the Special operating condition applied. The main injection HE, in which the essential portion of fuel of the Brenn engine is clearly late postponed. It occurs after top dead center OT. Before the Main injection HE there is a first pre-injection VE1. This is used to condition the combustion chamber before Main injection. For conditioning the combustion chamber the first pilot injection VE1 is a second pilot injection VE2 provided. The first pre-injections take place indirectly before or in the area of top dead center. Because teren is in the first pilot injection VE1 compared to An increased amount of fuel is metered in normal operation.

In Fig. 3, the device according to the invention is shown as a block diagram. Elements already described in FIG. 1 are identified by corresponding reference numerals.

The second partial control 134 supplies a variable to a correction value determination 300 , which indicates whether a special operating state is present. An internal combustion engine with a particle filter is a size B that characterizes the loading state of the filter 114 . The correction value determination 300 applies a correction 310 with correction values DFB and DME. The first sub-controller applies the correction with signals FB and ME. The correction then supplies the signal AD to the fuel metering unit.

On the basis of various signals, the first partial control calculates signals that determine the start of injection FB and the injection duration ME. This calculation is carried out both for the main injection and for the pre-injections. If the correction value determination 300 detects that a special operating state is present, it supplies the correction values DFB and DME to the correction 310 . The start of the injection is corrected using the signal DFB and the duration of the injection is corrected using the DME signal. The correction value DFB is chosen so that the injection as shown in Fig. 2 Darge is shifted in the late direction. The correction value DME is chosen so that the torque given off by the internal combustion engine remains constant. Furthermore, the correction value DME, especially in the pre-injection, is chosen so that the emissions are reduced.

In FIG. 4 is a flowchart shown for explaining the procedure of the invention. In a first step, various sizes are recorded. For example, the loading state B of the filter 114 is determined. The subsequent query 410 checks whether there is a special operating state. This is the case, for example, when the loading state B exceeds a threshold value. If there is no special operating state, step 400 follows again. If there is a special operating state, the measures described above are initiated in step 420 .

In the case of an internal combustion engine with a supercharger, the first step is different. Variables, such as the speed and / or a load size detected. The subsequent query 410 checks whether there is a special operating state. This is the case, for example, when the speed N is lower and / or the load is greater than a threshold value. If there is no special operating state, step 400 follows again.

If there is a special operating state, the measures described above are initiated in step 420 .

It is particularly advantageous that by moving the Combustion center towards late, the Turbinenlei performance of the charger increases significantly with the same exhaust emissions can be replaced.

The increase in fuel consumption is mini miert that the measure only in the presence of the Sonderbe drive state, such as when accelerating low speeds and / or for regeneration of the particle filters, is used.

The second pre-injection enables the main injection be moved very far late without large Emissions occur.

Claims (7)

1. Method for controlling an internal combustion engine, the Means comprises be the exhaust gas of the internal combustion engine influence, given certain conditions a special operating state is initiated in which a increased energy content of the exhaust gas is desired, wherein a combustion focus in the special operating state is influenced so that the exhaust gas temperature he increases. 2. The method according to claim 1, characterized in that the focus of combustion shifted towards late becomes. 3. The method according to claim characterized in that in the special operating state at least a first and a second pilot injection before a main injection follows. 4. The method according to any one of the preceding claims, characterized characterized that it is the agent that the exhaust affect around a loader, a particle filter and / or a catalyst.   5. The method according to any one of the preceding claims, characterized characterized in that the special operating state is initiated if a quantity that corresponds to the loading status of Par tikelfilters characterized, a threshold above increases. 6. The method according to any one of the preceding claims, characterized characterized that special operating condition initiated is when an increase in the performance of the loader ge wishes. 7. Device for controlling an internal combustion engine, the Means comprises be the exhaust gas of the internal combustion engine influence, given certain conditions a special operating state is initiated in which a increased energy content of the exhaust gas is desired with Means that burn in the special operating state influence focus such that the Abga temperature increased.