WO2007131807A1

WO2007131807A1 - Injection device, location of said device in an internal combustion engine and method and device for operating said internal combustion engine

Info

Publication number: WO2007131807A1
Application number: PCT/EP2007/050450
Authority: WO
Inventors: Olaf Graupner; Andreas Pfeifer
Original assignee: Continental Automotive Gmbh
Priority date: 2006-05-15
Filing date: 2007-01-17
Publication date: 2007-11-22
Also published as: DE102006022599B4; DE102006022599A1

Abstract

An injection valve (20) of an injection device is coupled to a fuel tank (17) and to a urea tank (19) in such a way that the injection valve (20) simultaneously and/or alternately meters fuel from the fuel tank (17) and/or an aqueous urea solution from the urea tank (19).

Description

description

Injection device, arrangement of the injection device in an internal combustion engine and method and apparatus for operating the internal combustion engine

The invention relates to an injection device with an injection valve. Furthermore, the invention relates to an arrangement of the injection device in an internal combustion engine. Furthermore, the invention relates to a method and an apparatus for operating the internal combustion engine.

Increasingly stringent statutory regulations regarding the pollutant emissions of internal combustion engines, make ever newer measures required by the pollutant emissions of internal combustion engines are reduced. For example, in diesel internal combustion engines, particle filters for filtering soot particles are preferably arranged in an exhaust gas tract of the internal combustion engine. Such a particulate filter may be regenerated, for example by generating who are burned ^¬, so that deposits of soot particles in the particulate filter in the exhaust tract, very high temperatures, for example about 600 degrees. These high temperatures in the exhaust system, for example, by injecting fuel generated in the hot exhaust gas tract, if there enough Sauer ^¬ material is present which can react with the fuel.

If the internal combustion engine operated with a lean air-fuel mixture, as it is during a combustion process of the internal combustion engine more oxygen Ver ^¬ addition as can react with the injected fuel. This leads compared to a stoichiometric operation of the internal combustion engine increasingly to the formation of nitrogen oxides, which are then contained in the exhaust gas. Such nitrogen oxides can be reduced to elemental nitrogen and water, for example in the presence of urea in an SCR catalyst. For example, a urea water solution can be metered directly into the exhaust tract. From DE 196 50 559 Cl a connection element for Einlei ^¬ th of fuel and a second fluid, in an injection valve is known. The connection element serves to introduce a mass flow of a second fluid, which is metered depending on engine operation and which is subject to great fluctuations, into the fuel feed of an injection valve. The second fluid is mixed with the fuel at the same time. In particular, the introduction of a water-fuel emulsion can be inexpensively retrofitted with the connection element regardless of the injector concepts used.

The object of the invention is an injection device, an arrangement of the injection device in an internal combustion engine and a method and a device for operating the

To provide internal combustion engine, by which or the pollutant emissions of the internal combustion engine can be easily and effectively reduced.

The object of the invention is achieved by the features of the independent claims. Advantageous embodiments of the invention are specified in the subclaims.

The invention is characterized according to a first aspect of the invention by an injection device with an injection valve. The injection valve is coupled to a fuel tank ^¬ and a urea tank so that can be metered to the injection valve simultaneously and / or alternately fuel from the fuel tank and / or the urea water from the urea tank. This allows the gleichzeiti ^¬ ge and / or alternate metering of the urea water and / or fuel with only one injection device, in particular with only one injection valve. The metering of the urea water solution and / or fuel with only one injection device can help to save costs and installation space when mounting the injection device. In an advantageous embodiment of the injection device, the injection valve communicates via a urea line with the urea tank. Furthermore, the injection valve communicates with the fuel tank via a fuel line. The injector comprises at least one urea valve and a fuel valve, by which a Harnstoffström Bezie ^¬ hung, a flow of fuel through the injection valve from ^¬ is gebbar. This allows particularly easy the gleichzei ^¬ term and / or alternate metering of the urea water and / or fuel with only one injection device, especially with only one injector.

The invention is characterized according to a second aspect of the invention by an arrangement of an SCR catalytic converter, a particulate filter and the injection device in an internal combustion engine with an exhaust gas tract. The SCR catalyst and the injection device are arranged in the internal combustion engine, that the exhaust gas tract can be metered through the injection valve urea water and / or fuel and in that the SCR catalytic converter in the exhaust tract downstream of a ^¬ is arranged injection valve and that the particulate filter in the exhaust system downstream of the SCR catalyst is arranged.

This enables the simultaneous and / or alternating metering of the urea water solution and / or fuel into the exhaust gas tract with only one injection device, in particular with only one injection valve. Furthermore, this helps to save costs and installation space when mounting the injection device for urea water solution and fuel into the internal combustion engine.

Injecting the fuel into the exhaust tract may help to regenerate the particulate filter in the exhaust tract. Injecting the urea water solution into the exhaust tract, in conjunction with the SCR catalyst, can help

To reduce nitrogen oxides of the exhaust gas. Thus, the arrangement, in particular by the injection device, simple and effective pollutant emissions of the internal combustion engine be reduced. Furthermore, the arrangement of the SCR catalyst close to the combustion chamber, in particular without a particle filter connected therebetween, contributes to a rapid warming up of the SCR catalytic converter to its operating temperature and thus also contributes to an advantageous starting behavior of the SCR catalytic converter.

The invention is characterized according to a third aspect of the invention by a method for operating the internal combustion engine, which comprises the arrangement. To operate the

Internal combustion engine are the exhaust tract through the injection ^¬ valve simultaneously or alternately metered urea water solution and / or fuel. This makes it possible to reduce the pollutant emissions of the internal combustion engine in a particularly effective manner.

In an advantageous embodiment of the third aspect of the invention, a temperature of the exhaust gas in the exhaust gas at the injection valve is adjusted so that at the time of Zumesen the fuel, the temperature of the exhaust gas in the exhaust system at the injection valve is higher than a boiling temperature of the fuel. This contributes to the fact that preferably as little as possible liquid fuel enters the SCR catalyst. Furthermore, this makes it possible to burn off deposits of the urea-water solution in the exhaust gas tract.

In a further advantageous embodiment of the third aspect of the invention, a metering of the urea-water solution is prevented during a regeneration of the particle filter. This helps prevent secondary reactions of the urea at high temperatures to regenerate the particulate filter.

The advantageous embodiments of the method can be readily transferred to advantageous embodiments of the device. The invention is explained in more detail below with reference to schematic drawings.

Show it:

1 shows an internal combustion engine,

Figure 2 is a flowchart of a first program for

Operating the internal combustion engine,

Figure 3 is a flowchart of a second program for

Operating the internal combustion engine.

Elements of the same construction or function are identified across the figures with the same reference numerals.

An internal combustion engine (FIG. 1) comprises an intake tract 1, an engine block 2, a cylinder head 3 and an exhaust tract 4. The intake tract 1 preferably comprises a throttle valve 5, a collector 6 and a suction pipe 7 which leads to a cylinder Z1-Z4 is guided via an inlet channel into a combustion chamber 9 of the engine block 2. The engine block 2 comprises ei ^¬ ne crankshaft 8, which is coupled via a connecting rod 10 with a piston 11 of the cylinder Zl. The internal combustion engine preferably comprises a plurality of cylinders Z1-Z4. The internal combustion engine is preferably a diesel internal combustion engine, and preferably arranged in a motor vehicle is ^¬.

In the cylinder head 3, a fuel injection valve 18 is preferably arranged, which communicates with a fuel tank 17 and which is supplied by a fuel pump 15 with fuel from the fuel tank 17. Alterna tively ^¬ the fuel injection valve 18 may be also arranged in the intake manifold. 7

An injection device comprises an injection valve 20, the fuel pump 15, the fuel tank 17, a urea pump. The urea tank 19 communicates with the injection valve 20 via a urea line. The injection valve 20 is supplied with urea water solution from the urea tank 19 by the urea pump 16. The fuel tank 17 communicates via a first force ^¬ fuel line to the injection valve 20 and via a second fuel line to the fuel injection valve 18 Fer ^¬ ner preferably comprises the injection device, a urea valve and a fuel valve, which preferably with the urea line or the fuel line or the Injection valve 20 are coupled, that through the urea valve, a urea water solution flow through the injection valve 20 can be predetermined and that a fuel flow through the injection valve 20 can be predetermined by the fuel ^¬ fuel valve. Downstream of the injection valve 20 is preferably a mixing device 21 angeord ^¬ net in the exhaust system 4. The fuel and the urea water solution, which are attributed to the exhaust tract 4 through the injection valve 20, mix primarily with the exhaust gas in the mixing device 21. Downstream of the mixing device 21, a SCR catalyst 23 and downstream of the SCR catalyst 23, a particulate filter 24 are preferably arranged. The particulate filter 24 is suitable for filtering soot particles in the exhaust gas.

A control device 25 is provided which is associated with sensors which detect different measured variables and in each case determine the value of the measured variable. Operating variables include the measured variables and variables derived therefrom of the internal combustion engine. Operating variables can be representative of a current operating state of the internal combustion engine. The aktuel ^¬ le operating state, for example, be an operation of the internal combustion ^¬ engine with a throttled or unthrottled air mass flow into the combustion chamber 9 and / or operation of the internal combustion engine with a lean or rich air-fuel mixture. The control device 25 determines, depending on at least one of the operating variables, at least one manipulated variable, which is then divided into one or more actuating signals for controlling the actuators by means of corresponding positioning elements. be implemented. The control device 25 may also be referred to as an apparatus for operating the internal combustion engine.

The sensors are, for example, a pedal position sensor 26, which detects an accelerator pedal position of an accelerator pedal 27, an air mass sensor 28 which detects an air mass flow upstream of the throttle valve 5, from which the air mass flow into the combustion chamber 9 can be determined, a temperature sensor 32, the one Intake air temperature detected, a

Intake manifold pressure sensor 34 which detects an intake manifold pressure in the collector 6, a crankshaft angle sensor 36 which detects a crankshaft angle, which is then assigned a speed of the internal combustion ^¬ machine, a lambda probe 37, through which an air-fuel ratio in the combustion chamber 9 are determined can, and an exhaust gas probe 38, can be detected by the pollutants in the exhaust downstream of the particulate filter 24.

Depending on the embodiment of the invention, any subset of said sensors may be present, or additional sensors may also be present.

The actuators are, for example, the throttle valve 5, the gas inlet and gas outlet valves 12, 13, the fuel injection valve 18 and / or the urea injection valve 20.

In a lean operation of the internal combustion engine less fuel supplied ^¬ is measured for a combustion process in the combustion chamber 9 when burned with the oxygen in the combustion chamber 9 advertising the can. As a result, nitrogen oxides, which are then contained in the exhaust gas, are formed increasingly as compared to a stoichiometric operation of the internal combustion engine. The nitrogen oxides are environmentally damaging and harmful ^¬. If urea water solution is metered into the exhaust tract 4 during lean-burn operation of the internal combustion engine, the metered urea-water solution mainly mixes with the exhaust gas in the mixing device 21. In particular, nitrogen oxides of the exhaust gas mix with ammonia, which in a chemical reaction urea. In the presence of ammonia ^¬ reagie ren the nitrogen oxides in the SCR catalyst 23 to elemental nitrogen and water vapor.

After a long period of operation of the particulate filter 24, an exhaust gas back pressure, which is present at the particulate filter 24, can increase sharply due to soot deposits in the particulate filter 24. The greatly increased exhaust back pressure leads to a deteriorated fuel consumption of the internal combustion engine. Egg ne DPF_RGN regeneration of the particulate filter 24 can be done in game ^¬ by the exhaust gas is set so high a temperature EG_TEMP that the soot deposits in the particulate filter burn 24th The required high temperature Tempe ^¬ EG_TEMP of the exhaust gas can for example be about 600 degrees. Nitrogen oxides contained in exhaust gas, these can be reduced in the presence of urea in the SCR catalyst 23 to elementa ^¬ rem nitrogen and water. Thus contributes ^¬ contribute to a reduction in pollutant emissions of the engine probably the metering of fuel to the exhaust section 4 and the metering of the urea solution to the exhaust tract. 4

A first program (FIG. 2) for operating the internal combustion engine is preferably stored on a storage medium of the control device 25. The first program is used only to meter the fuel to the exhaust gas duct 4, when the temperature of the exhaust gas EG_TEMP is higher than the Siedetempe ^¬ temperature of the fuel. This causes the fuel to be gaseous prior to reaching the SCR catalyst 23 and thus no liquid fuel enters the SCR catalyst 23. This helps to prevent fouling of the SCR catalyst 23 by the fuel. Furthermore, increasing the exhaust temperature EG_TEMP via the boiling temperature of the fuel to that typical deposit products of the urinary material, such as cyanuric acid and its derived products ^¬ te be burned. The first program is preferably started in a timely manner an engine start of the internal combustion engine in a step Sl. If necessary, variables are initialized in step S1.

In a step S2 it is checked whether a metering FUEL_INJ of fuel is to be made in the exhaust tract 4. If the condition of step S2 is not fulfilled, the processing is continued again in step S2. Is the Bedin ^¬ supply of step S2 is satisfied, the processing is continued in egg nem step S3.

In step S3 it is checked whether the temperature EG_TEMP of the exhaust gas is greater than a predetermined threshold value THD. The threshold value THD preferably corresponds to a boiling temperature of the fuel. If the condition of step S3 is not satisfied, the processing is continued in step S4. If the condition of step S3 is satisfied, the processing is continued in step S5.

In step S4, the exhaust gas temperature EG_TEMP is increased RAISE. The exhaust gas temperature EG_TEMP can be increased RAISE, for example, by an air mass flow is lowered to the combustion chamber 9 and / or that an internal engine Nachein ^¬ injection is made. In the case of internal engine post-injection, fuel is metered into the combustion chamber 9 of the internal combustion engine shortly before the air mass is expelled from the combustion chamber 9. This can react with the residual oxygen in the exhaust gas, which leads to an increase in the temperature EG_TEMP of the exhaust gas.

In step S5, the fuel is metered into the exhaust tract 4 FUEL_INJ.

In a step S6, the first program can be ended. Preferably, however, the first program during loading ^¬ the internal combustion engine drive executed regularly. Alternatively or additionally, a second program (FIG. 3) is preferably stored on the storage medium of the control device 25. The second program serves to prevent metering AMM_INJ of urea water solution during regeneration DPF_RGN of the particulate filter 24.

Further, increasing the exhaust gas temperature EG_TEMP leads above the boiling point of the fuel to the fact that typical storage ^¬ addition products of the urea water, for example, cyanuric acid and their derivatives are burned.

When to regenerate the particulate filter 24 DPF_RGN necessary high temperature of the exhaust gas EG_TEMP a response ^¬ degree is greatly reduced 23 of the SCR catalyst. Further, at such a high temperature EG_TEMP of the exhaust gas undesired secondary reactions of the urea may occur. The suppression of the metering AMM_INJ of the urea water solution during the regeneration DPF_RGN of the particulate filter 24 thus contributes to the avoidance of increased pollutant emissions. The second program is preferably according to

Step Sl of the first program gestar ^¬ tet in a step S7.

In a step S8 it is checked whether the urea water solution is to be metered AMM_INJ. Is the condition of

Step S8 is not satisfied, the processing is continued again in step S8. If the condition of step S8 it fills ^¬, processing in a step S9 sets fortge ^¬.

In step S9, it is checked whether a regeneration DPF_RGN of the particulate filter 24 is currently being performed. If the Be ^¬ dingung of step S9 is satisfied, the processing he ^¬ neut continues at step S7. If the condition of Schrit- tes S9 is not met, in a step S urinary ^¬ material water solution is metered AMM_INJ. In a step Sil, the second program can be ended. Preferably, however, the second program is regularly currency ^¬ rend executed operation of the internal combustion engine.

The invention is not limited to the specified Ausführungsbei ^¬ games. For example, the exhaust tract 4 may have no or additional mixing devices 21. Furthermore, the SCR catalyst may also be arranged downstream of the particulate filter 24. Furthermore, the first and / or the second program can be implemented in a program.

Claims

Claims:

1. Injection device with an injection valve (20) which is coupled to a fuel tank (17) and a urea tank (19) so that simultaneously with the injection valve (20) and / or alternately fuel from the fuel tank ^¬ (17) and / or urea water solution from the urea tank (19) is edible.

2. Injection device according to claim 1,

- In which the injection valve (20) via a urea line with the urea tank (19) communicates and communicates via a force ^¬ fuel line to the fuel tank (17), and

comprising at least one urea valve and a fuel valve through which a urea water solution stream or a

Fuel flow through the injection valve (20) can be predetermined.

3. Arrangement of an SCR catalyst (23), a Partikelfil ^{¬ age} (24) and the injection device according to one or more of the preceding claims in an internal combustion engine with an exhaust tract (4), so that the exhaust tract (4) through the injection valve (20) urea water solution and / or fuel can be metered and that the SCR catalytic converter (23) is arranged in the exhaust gas tract (4) downstream of the injection valve (20) and that the particle filter (24) is located in the exhaust gas duct (4) downstream of the SCR Catalyst (23) is arranged.

4. A method for operating an internal combustion engine, comprising the arrangement according to claim 3, in which the exhaust gas tract (4) through the injection valve (20) simultaneously or alternately ^¬ selnd urea water solution and / or fuel are metered (AMM_INJ, FUEL_INJ).

5. The method of claim 4, wherein a temperature (EG_TEMP) of an exhaust gas in the exhaust tract (4) on the injection valve (20) is set so that at the time of metering (FUEL_INJ) of the fuel, the temperature (EG_TEMP) of the exhaust gas ses in the exhaust tract (4) on the injection valve (20) is higher than a boiling point of the fuel.

6. The method according to any one of claims 4 or 5, wherein during a regeneration (DPF_RGN) of the particulate filter (24) a metering (AMM_INJ) of the urea water solution is suppressed.

7. An apparatus for operating an internal combustion engine with the arrangement according to claim 3, wherein the apparatus is adapted for simultaneous or alternating metering (AMM_INJ, FUEL_INJ) of urea water solution and / or fuel to the exhaust tract (4) through the injection valve (20).