DE102012015745A1 - Fuel injection apparatus for direct injecting petrol engine in motor car, has high pressure injector arranged in intake tract such that fuel is injected to engine in upstream manner under pressure on inlet valve in closed state - Google Patents

Abstract

The apparatus (1) has a high pressure injector (8) comprising an inlet valve (6) discontinuously connected with a combustion chamber (2). The high pressure injector is arranged in an intake tract (7) such that fuel (9) is injected into an internal combustion engine (3) in upstream manner under pressure on the inlet valve in a closed state in adjustable time and crank-angle-related injection duration. Fuel supply is controllable such that the fuel is fed in single interval or in successive intervals in full-load operation of the internal combustion engine. Independent claims are also included for the following: (1) a method for controlling an injection apparatus (2) a computer program including a set of instructions to perform a method for controlling an injection apparatus (3) a motor car.

Description

The invention relates to an injection device for an internal combustion engine, in particular for an internal combustion engine in a motor vehicle, and to a method for controlling an injection device, in particular for an internal combustion engine in a motor vehicle.

Current and future gasoline engines are faced with ever stricter emission limits by the legislature. So finds today in motor vehicles the EURO-6 standard Application that can be achieved in direct injection gasoline engines under certain circumstances only by the use of particulate filters.

An object of the invention is to provide an injection device for a gasoline engine, which allows a further reduction of particulate emissions, for example, to achieve compliance with an applicable emission standard without the use of a particulate filter.

This object is solved by the features of patent claim 1 or 8. Further advantageous embodiments of the invention are each the subject of the dependent claims. These can be combined in a technologically meaningful way. The description, in particular in conjunction with the drawing, additionally characterizes and specifies the invention.

According to the invention, an injection device for an internal combustion engine, in particular for an internal combustion engine in a motor vehicle, is provided, which is suitable for supplying a combustion chamber provided with an inlet valve discontinuously with fuel via a high-pressure injector. The high-pressure injector is arranged in an intake tract and is configured so that the fuel in a partial load operation of the internal combustion engine under pressure with adjustable time and angle-related injection duration upstream of the inlet valve located in a closed state.

According to the invention, a high pressure port injection is used. The high pressure injector is mounted in the inlet duct and injects toward the intake valve (s). The fuel is injected upstream of the hot intake valve in the exhaust-relevant operating range during the exhaust phase with high fuel pressure. By this flow-hydraulic and thermal treatment favorable engine particle emissions are achieved within the engine, which allow z. B. the Euro-6 standard without meeting particulate filter. The fuel consumption is in part-load operation at the same compression ratio lower than in comparison to the direct injection. Furthermore, the injector is more cost effective over direct injection due to simpler cylinder head design and reduced high pressure system requirements. The injector provides additional degrees of freedom for the combustion chamber geometry because the injector does not need to be housed in the cylinder head. Compared to direct injection, there is a larger available valve area and construction space in the cylinder head, which can be used, for example, for valve timing or cylinder deactivation systems. Brennverfahrenstechnisch can be used instead of a complicated piston mold in the direct injection, a low-efficiency flat piston. In turbocharged engines, this allows the use of a smaller valve spread of the high pressure injector due to the unrestricted injection duration.

In one embodiment, the fuel supply is controllable so that in the partial load operation of the fuel up to a crank angle of 440 ° before top dead center in the power stroke can be fed.

The fuel can be stored upstream in comparison to the direct injection and in the early crank angle with an injection end of about 440 ° before top dead center in the power stroke and speed-dependent and load-dependent corrective injected. It is already injected during the exhaust phase of the four-stroke engine on the closed, hot intake valves.

In a further embodiment, the injection device injects the fuel at a partial load operation at a pressure of 30 bar to 70 bar, preferably 50 bar.

The fuel pressure is adjusted to a level of about 50 bar, which provides good jet conditioning and good fuel atomization but also allows to cover a wide load range with equal or little modulated pressure. Here, preferably, the injection time is adjusted to achieve a more precise dynamic behavior. The fuel is thus treated well and has significantly more time to evaporate. Favoring effect here is that the intake valves located in the jet direction during operation of the internal combustion engine are hot. Accordingly, the fuel-air mixture is sucked in gaseous form with good homogeneous distribution. Fat mixture zones in the combustion chamber are reduced. Since the fuel is introduced into the combustion chamber together with the air, significantly less liquid fuel reaches the combustion chamber walls. In particular, the risk of diffusion flames on the piston crown (called "Pool Fire" in English) is significantly reduced, the efficiency-degrading and significantly contribute to particulate emissions in direct-injection gasoline engines. In the case of direct-injection spark-ignition engines, this effect is counteracted by sophisticated technology (such as piezo injectors, pressure increase to more than 200 bar, highly developed magnetic injectors), which means a significant overhead and additional costs.

In a further embodiment, the fuel supply is controllable such that in a full load operation of the internal combustion engine, preferably the total amount with the intake valve open, preferably the entire fuel in a single interval with at least partially open intake valve can be fed.

In full-load operation, a late injection-synchronous injection position is selected. The injection in this phase with high gas dynamics, which results from the formation of the Schwingrohraufladung or turbocharging in the inlet channel at full load, leads to a reduced wall wetting. This increases the charge cooling, the degree of delivery, the medium pressure, power and torque. The knock limit is positively influenced and it can be ignited earlier, which causes an increase in efficiency by a better position of the center of gravity of the combustion.

In a further embodiment, the fuel supply is controllable so that in a full load operation of the internal combustion engine preferably all the fuel in two or more consecutive intervals at least partially open inlet valve can be supplied, and that in the full load operation of the fuel up to a crank angle of 240 ° before the top dead center in the power stroke is fed.

A multiple injection mode can be used to generate additional torque increase and emission reduction.

In a further embodiment, the injector injects the fuel at full load operation at a pressure of 60 bar or more, preferably in the range between 80 bar and 120 bar.

In a further embodiment, the time and crank angle-related injection duration can be selected depending on the load in the injection device.

Furthermore, an internal combustion engine is specified in a motor vehicle having an injection device described above.

• – Bereitstellen einer Einspritzvorrichtung die geeignet ist, über einen Hochdruckinjektor einen mit einem Einlassventil versehenen Brennraum diskontinuierlich mit einstellbarer zeitlicher und kurbelwinkelbezogener Einspritzdauer mit Kraftstoff zu versorgen, wobei der Hochdruckinjektor in einem Einlasstrakt angeordnet ist,
• – Bestimmen eines Lastzustandes der Verbrennungskraftmaschine,
• – Zuführen von Kraftstoff der Verbrennungskraftmaschine auf das sich in einem geschlossenen Zustand befindliche Einlassventil, falls sich die Verbrennungskraftmaschine in einem Teillastbetreib befindet; und
• – Zuführen von Kraftstoff der Verbrennungskraftmaschine auf das sich in einem wenigstens teilweise geöffneten Zustand befindliche Einlassventil, falls sich die Verbrennungskraftmaschine in einem Volllastbetreib befindet.

In a further aspect of the invention, a method is specified for controlling an injection device, in particular for an internal combustion engine in a motor vehicle, in which the following steps are carried out:

• Providing an injection device which is suitable for supplying fuel to a combustion chamber provided with an inlet valve discontinuously with adjustable time and angle-related injection duration via a high-pressure injector, the high-pressure injector being arranged in an intake tract,
• Determining a load state of the internal combustion engine,
• Supplying fuel of the internal combustion engine to the intake valve which is in a closed state if the internal combustion engine is in a partial load operation; and
• Supplying fuel of the internal combustion engine to the intake valve located in an at least partially open state if the internal combustion engine is in full load operation.

Due to the more favorable fuel treatment, better fuel conversion rates (especially for hydrocarbons, nitrogen oxides and carbon monoxide), lower pump drive losses (lower fuel pressure requirement), smoother running at low loads and better compatibility with exhaust gas recirculation can be achieved. Fuel consumption and emissions are reduced. This compensates for a possibly slightly lower compression ratio than high pressure direct injection in terms of fuel consumption and emissions of the main pollutant components (hydrocarbons, nitrogen oxides and carbon monoxide) to be oxidized. However, this method can also be equipped with a higher compression compared to a port injection. The partial load combustion efficiency at the same compression ratio for this method is above that of the direct injection.

In one embodiment of the method, the fuel supply is controlled so that in the partial load operation, the fuel is supplied up to a crank angle of 440 ° before top dead center in the power stroke.

In a further embodiment of the method, the fuel supply is controlled so that in a full load operation of the internal combustion engine preferably all the fuel is supplied in a single interval or in at least two successive intervals at at least partially open inlet valve.

In a further embodiment of the method, the fuel is injected at full load with a pressure of 60 bar or more, preferably in the range between 80 bar and 120 bar and in part-load operation, the fuel at a pressure of 30 bar to 70 bar, preferably 50 bar, injected.

In a further embodiment of the method, the time and crank angle-related injection duration of the fuel injection is selected as a function of speed or load.

The described method for controlling an injection device, in particular for an internal combustion engine, may be provided in a motor vehicle, in particular in a control unit. Expediently, the control unit has a storage means with a computer program stored thereon, the computer program serving to carry out the method according to the invention.

The control unit may have a digital microprocessor unit (CPU) data-connected to a memory system and a bus system, a random access memory (RAM) and a memory means. The CPU is adapted to execute instructions executed as a program stored in a memory means, to detect input signals from the data bus and to output output signals to the data bus. The storage system may have various storage media such as optical, magnetic, solid state and other non-volatile media on which a corresponding computer program for carrying out the method and the advantageous embodiments is stored. The program may be arranged to embody or perform the methods described herein so that the CPU may perform the steps of such methods and thereby control the motor vehicle.

Suitable for performing a method is a computer program having program code means for performing all the steps of any one of the claims when the program is run on a computer.

The computer program may have program code means for carrying out all the steps of the method and, if appropriate, the embodiments mentioned in the subclaims when the program is executed on a computer. The computer program can be easily read into existing control units and used to control a lane departure warning system.

Provided for this purpose is a computer program product with program code means, which are stored on a computer-readable data carrier in order to carry out the method according to any of the claims, when the program product is executed on a computer. The computer program can also be integrated as a retrofit option in control units.

• – Mittel zum Bereitstellen einer Einspritzvorrichtung die geeignet ist, über einen Hochdruckinjektor einen mit einem Einlassventil versehenen Brennraum diskontinuierlich mit einstellbarer zeitlicher und kurbelwinkelbezogener Einspritzdauer mit Kraftstoff zu versorgen, wobei der Hochdruckinjektor in einem Einlasstrakt angeordnet ist,
• – Mittel zum Bestimmen eines Lastzustandes der Verbrennungskraftmaschine,
• – Mittel zum Zuführen von Kraftstoff der Verbrennungskraftmaschine auf das sich in einem geschlossenen Zustand befindliche Einlassventil, falls sich die Verbrennungskraftmaschine in einem Teillastbetreib befindet, und
• – Mittel zum Zuführen von Kraftstoff der Verbrennungskraftmaschine auf das sich in einem wenigstens teilweise geöffneten Zustand befindliche Einlassventil, falls sich die Verbrennungskraftmaschine in einem Volllastbetreib befindet.

Another aspect of the invention relates to an apparatus for controlling an injection device, in particular for an internal combustion engine specified in a motor vehicle, comprising:

• Means for providing an injection device which is suitable for supplying fuel via a high-pressure injector to a combustion chamber provided with an inlet valve discontinuously with adjustable time and crank angle-related injection duration, the high-pressure injector being arranged in an intake tract,
• Means for determining a load state of the internal combustion engine,
• - Means for supplying fuel of the internal combustion engine to the located in a closed state inlet valve, if the internal combustion engine is in a part-load operation, and
• - Means for supplying fuel of the internal combustion engine to the located in an at least partially open state intake valve, if the internal combustion engine is in a full load operation.

In one embodiment of the apparatus In one embodiment of the method, the fuel supply is controlled so that in the partial load operation, the fuel is supplied up to a crank angle of 440 ° before top dead center in the power stroke.

In a further embodiment of the apparatus, the fuel supply is controlled so that in a full load operation of the internal combustion engine preferably all the fuel is supplied in a single interval or in at least two successive intervals at least partially open inlet valve.

In a further embodiment of the apparatus, the fuel is injected at full pressure with a pressure of 60 bar or more, preferably in the range between 80 bar and 120 bar, and in partial load operation, the fuel at a pressure of 30 bar to 70 bar, preferably 50 bar injected.

In a further embodiment of the apparatus, the time and crank angle-related injection period of the fuel injection is selected depending on the speed or load.

Furthermore, a motor vehicle with a control unit for an injection device, wherein the control unit has a storage means with a computer program stored thereon, wherein the Computer program is equipped to carry out the method described above.

Some embodiments will be explained in more detail with reference to the drawing. Show it:

1 : an injection device according to the invention in a sectional view,

2 FIG. 2 is a diagram for explaining the method according to the invention or the injection device according to the invention, FIG.

3 FIG. 2 shows another diagram for explaining the method according to the invention or the injection device according to the invention, FIG.

4 a further diagram for explaining the method according to the invention or the injection device according to the invention, and

5 : Steps of the method according to the invention in a flow chart.

In the figures, identical or functionally identical components are provided with the same reference numerals.

In 1 is an injector 1 along with a section through a combustion chamber 2 an internal combustion engine 3 shown. The internal combustion engine 3 has a piston 4 on. Above the combustion chamber 2 is a spark plug 5 arranged. The combustion chamber 2 is via an inlet valve 6 from an inlet tract 7 separated. In the inlet tract 7 is a high pressure injector 8th arranged, the part of the injector 1 is. The high-pressure injector 8th is suitable for fuel 9 in the inlet tract 7 inject.

The injector 1 supplied via the high-pressure injector 8th the with the inlet valve 6 provided combustion chamber 2 discontinuous with fuel. The high-pressure injector 8th is in the inlet tract 7 arranged and designed so that the fuel 9 in a part load operation of the internal combustion engine 3 pressurized with adjustable time and crank angle related injection duration upstream of the intake valve located in a closed state 6 meets.

In this case, the fuel supply is controlled so that in the partial load operation of the fuel 9 up to a crank angle of 440 ° before top dead center in the power stroke can be fed. In part-load operation, the fuel becomes 9 injected at a pressure of about 50 bar.

The fuel 9 can be pre-stored compared to direct injection and injected in early crank angle to approximately up to a crank angle of 440 ° before top dead center in the power stroke (speed and load-dependent correctable). This is already during the exhaust phase of the internal combustion engine 3 on the closed or hot inlet valves 6 injected. For this purpose, the fuel pressure is set to a level of about 50 bar, which brings good jet preparation and good fuel atomization but also makes it possible to cover a wide load range with the same or little modulated pressure. Here, preferably, the injection time is adjusted to achieve a more precise dynamic behavior. The fuel is thus treated well and has significantly more time to evaporate.

The pre-storage of the injection is in 2 for operation of the internal combustion engine 3 again schematically shown in the partial load range. The pressure is applied 10 in the combustion chamber 2 , a valve lift 11 of the inlet valve 6 and another valve lift 12 one not in 1 shown exhaust valve, each depending on a crank angle 13 , It can be seen that the injection duration 14 of the fuel 9 is upstream and in early positions of the crank angle 13 until approximately up to a crank angle of 440 ° before top dead center in the power stroke.

In future exhaust gas cycles, higher loads occur compared to current exhaust gas cycles. Even with low-pressure port injection (MPFI) massive particulate emissions can occur here because the fuel quantity can no longer be stored upstream at high loads due to longer injection times. According to this embodiment of the invention can be reduced with high-pressure port injection by the high pressure, the injection time and the amount of fuel even at high load is still completely upstream.

In full-load operation, a late injection-synchronous injection position is selected which sets an injection end crank angle of approx. 240 ° before top dead center in the working cycle (BTDC) at the highest possible pressure.

In a full load operation of the internal combustion engine 3 is preferably all the fuel in a single interval with at least partially open inlet valve 6 fed. But it is also possible in the form of a multiple injection the fuel 9 in two or more successive intervals at at least partially open inlet valve supply.

This is an increase in torque of the internal combustion engine 3 scores that are made an increase in air consumption and an improved knock limit composed. The injection and evaporation must take place at the end of the intake stroke in the shortest possible time and wetting of components can be avoided. The short injection duration is achieved by the high fuel pressure. The maximum air cooling is achieved by the component wetting in the channel and in the combustion chamber remains low.

For maximum air consumption, the additional time for the afterflow of fresh air must be given and optimized. The mixture temperature is lower the later injected - even after the bottom dead center. The knock limit is much cheaper with low mixture temperature.

The injection is in 3 and 4 for operation of the internal combustion engine 3 in the full load range again schematically shown. In turn, the pressure is applied 10 in the combustion chamber 2 , the valve lift 11 of the inlet valve 6 and the further valve lift 12 of the exhaust valve, depending on the crank angle 13 , In 3 is the injection duration 14 the single injection and in 4 the injection duration 14 and 14 ' the multiple injection shown.

In a method of controlling the injector 1 The following steps are performed, as also with reference to 5 is shown.

In step 100 there is a provision of the injection device 1 which is suitable over the high-pressure injector 8th the with the inlet valve 6 provided combustion chamber 2 discontinuous with adjustable time and crank angle-related injection duration 14 with fuel 9 to supply, whereby the Hochdruckinjektor 8th in the inlet tract 7 is arranged.

In step 101 there is a determination of the load state of the internal combustion engine 3 ,

In step 102 there is a supply of fuel 9 on the closed inlet valve 6 if the internal combustion engine 3 in a part-load operation.

Otherwise, done in step 103 supplying fuel to the opened intake valve 6 if the internal combustion engine is in full load operation.

Although some possible embodiments of the invention have been disclosed in the foregoing description, it is to be understood that numerous other variants of embodiments exist through the possibility of combining all of the cited and further all of the obvious technical features and embodiments. It is further understood that the embodiments are to be understood as examples only, which in no way limit the scope, applicability and configuration. Rather, the foregoing description would suggest a suitable way for the skilled person to realize at least one exemplary embodiment. It should be understood that in an exemplary embodiment, numerous changes in the function and arrangement of the elements may be made without departing from the scope and equivalents disclosed in the claims.

LIST OF REFERENCE NUMBERS

1

Injector

2

combustion chamber

3

Internal combustion engine

4

piston

5

spark plug

6

intake valve

7

inlet tract

8th

power injector

9

fuel

10

print

11

Valve lift inlet

12

Valve lift outlet

13

crank angle

14

Injection duration

14 '

Injection duration

100-103

steps

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• EURO-6 standard [0002]
• Euro 6 standard [0006]

Claims (15)

Injection device for an internal combustion engine, in particular for an internal combustion engine in a motor vehicle, which is suitable via a high-pressure injector ( 8th ) one with an inlet valve ( 6 ) provided combustion chamber ( 2 ) discontinuously with fuel ( 9 ), the high pressure injector ( 8th ) in an inlet tract ( 7 ) is arranged and designed so that the fuel ( 9 ) in a partial load operation of the internal combustion engine under pressure with adjustable time and crank angle related injection duration ( 14 ) upstream of the inlet valve located in a closed state ( 6 ) meets. An injection device according to claim 1, wherein the fuel supply is controllable such that in the partial load operation of the fuel ( 9 ) can be fed up to a crank angle of 440 ° before top dead center in the power stroke. Injection device according to claim 1 to 2, in which the fuel supply is controllable such that in a full-load operation of the internal combustion engine preferably the entire fuel ( 9 ) in a single interval ( 14 ) or in two or more successive intervals ( 14 . 14 ' ) at least partially open inlet valve ( 6 ) can be fed. Injection device according to one of claims 1 to 3, wherein in full-load operation the fuel ( 9 ) at a pressure of 60 bar or more, preferably in the range between 80 bar and 120 bar injected. Injection device according to one of claims 1 to 4, in which the fuel is at part-load operation ( 9 ) at a pressure of 30 bar to 70 bar, preferably 50 bar injected. Injection device according to one of claims 1 to 5, in which the temporal and crank angle-related injection duration ( 14 . 14 ' ) of the fuel injection is speed or load-dependent selectable. Internal combustion engine in a motor vehicle having an injection device ( 1 ) according to one of claims 1 to 6. Method for controlling an injection device, in particular for an internal combustion engine in a motor vehicle, in which the following steps are carried out: - providing an injection device ( 1 ) which is suitable via a high-pressure injector ( 8th ) one with an inlet valve ( 6 ) provided combustion chamber ( 2 ) discontinuously with adjustable time and crank angle related injection duration ( 14 ) with fuel ( 9 ), the high pressure injector ( 8th ) in an inlet tract ( 7 ), - determining a load state of the internal combustion engine, - supplying fuel ( 9 ) of the internal combustion engine to the in a closed state located inlet valve ( 6 ), if the internal combustion engine is in a part load operation, and - supplying fuel ( 9 ) of the internal combustion engine to the in an at least partially open state located intake valve ( 6 ), if the internal combustion engine is in a full load operation. The method of claim 8, wherein the fuel supply is controlled so that in the partial load operation of the fuel ( 9 ) is supplied to a crank angle of 440 ° before top dead center in the power stroke. The method of claim 8 to 9, wherein the fuel supply is controlled so that in a full load operation of the internal combustion engine, preferably the entire fuel ( 9 ) in a single interval ( 14 ) or in at least two consecutive intervals ( 14 . 14 ' ) at least partially open inlet valve ( 6 ) is supplied. Method according to one of claims 8 to 10, wherein in full load operation the fuel ( 9 ) is injected at a pressure of 60 bar or more, preferably in the range between 80 bar and 120 bar, and in the part-load operation of the fuel ( 9 ) is injected at a pressure of 30 bar to 70 bar, preferably 50 bar. Method according to Claims 8 to 11, in which the time duration and crank angle-related injection duration ( 14 . 14 ' ) of the fuel injection is selected speed or load-dependent. Computer program for carrying out a method according to one of Claims 8 to 12. A computer program comprising program code means stored on a computer readable medium for performing the method of any one of the preceding claims 8 to 12 when the program code means are executed on a computer. Motor vehicle with a control unit for an injection device ( 1 ), wherein the control unit has a storage means with a computer program stored thereon, the computer program being equipped to carry out a method according to one of claims 8 to 12.

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