DE102016203027A1 - Internal combustion engine - Google Patents

Abstract

An internal combustion engine having at least one cylinder and a gas supply passage and a gas exchange inlet valve between the cylinder and the gas supply passage for controlling a gas exchange from the gas supply passage into the cylinder and with a first fuel injector for introducing fuel from a fuel supply directly into the cylinder Cylinder and with a second fuel injector for introducing fuel from the fuel supply into the gas supply tract, wherein the second fuel injector, a second fluid from a fluid supply into the gas supply tract can be introduced. The inventive design, the advantages of the intake manifold injection in the partial load with the advantages of water injection in the full load can be combined.

Description

The invention relates to an internal combustion engine having the features of the preamble of patent claim 1.

From the patent application with the International Publication Number WO 2008/095783 A2 , from which the present invention proceeds, an internal combustion engine is known, with at least one directly into a combustion chamber of at least one cylinder opening first injector for direct fuel injection and at least one opening into an inlet flow path of the cylinder second injection device for indirect fuel injection, wherein in the inlet flow path at least one throttle is arranged, wherein at least one throttle valve is arranged downstream of the second injection device.

A disadvantage of this generic internal combustion engine that it has a relatively high particle emission and in the case of turbocharging at higher speeds and higher loads greased (lambda <1) must be operated.

Next is from the German patent application DE 10 2009 044 160 A1 a method for operating a spark-ignited internal combustion engine, comprising at least one catalyst in the exhaust system, with at least one opening in a suction pipe first injector and at least one opening into a combustion chamber second injection device, wherein in at least one operating range during a cycle of the fuel is supplied via both injectors and wherein the internal combustion engine is operated in at least one operating range in a catalyst heating mode, wherein at least in the catalyst heating mode, the total amount of fuel supplied is shared between the first injector and the second injector, and wherein the fuel injection via the first injector before or during an intake stroke and at least one fuel injection via the second injection device takes place during a compression stroke.

This method for operating a spark-ignited, generic internal combustion engine has the above-mentioned disadvantages.

In order to reduce the particle emission of a spark-ignited internal combustion engine, in the European patent application EP 2 789 839 A2 a system and method for water injection proposed for an internal combustion engine. From this patent application, a system for water injection for an internal combustion engine is known which has first injectors, each injecting a liquid directly into a combustion chamber of the internal combustion engine and second injectors, each injecting a liquid in a suction pipe in front of the combustion chamber. At least one fuel supply valve arranged between a fuel tank and the first and second injectors and a water supply valve arranged between a water reservoir and the first injectors are provided. The valves are switchable such that the first injectors are fluidly connected to the fuel tank both in fluid communication with the fuel tank and with the water reservoir and the second injectors. Water is only injected into the combustion chamber via the first injectors in certain load ranges. Fuel is injected depending on the load range either via the first injectors directly into the combustion chambers of the internal combustion engine or via second injectors in the intake manifold upstream of the combustion chambers.

Next is from the European patent EP 2 657 502 B1 a high pressure fuel rail for a fuel injection system for an internal combustion engine. The high-pressure fuel rail (common rail) is provided for a fuel injection system for an internal combustion engine having at least two cylinders, wherein for each cylinder, a fuel injector is provided, which are supplied via the high-pressure injection rail with fuel, wherein the fuel from a pump in the high-pressure injection rail is conveyed and wherein in the flow direction of the fuel in front of the pump, a mixing device is provided, in which the fuel with a second liquid fluid, for. As water is miscible, wherein an inner volume of the high-pressure injection rail is fuel-carrying connected to a second inner volume of a second container, wherein the second container is arranged in the installed position of the high pressure injection bar above.

The disadvantage is that the current state of the art in the suction channel (gas supply tract) of the internal combustion engine only one of the two systems (gasoline or water injection) allows. A particular problem is to accommodate the injector as close as possible to the gas exchange inlet valve in order to use the evaporation energy of water or gasoline ideally in the combustion chamber. In the very tight package of today's internal combustion engines, it is without omission of other important systems, such. B. a variable valve timing, not possible to accommodate both injectors simultaneously close to the gas exchange inlet valve. However, if this problem is solved, the cost of a system consisting of three different types of injectors (gasoline direct injection, gasoline multipoint injection and water multi-point injection) is far too high for a business case.

Object of the present invention is to show an arrangement with which the above-mentioned disadvantages are eliminated.

This object is achieved by the feature in the characterizing part of patent claim 1.

The invention enables the benefits of multi-point injection (MPI) at part-load (reduced fuel consumption, protection against gas exchange intake valve coking, reduced friction and reduced emissions) with the benefits of water injection (reduced knock limit, no enrichment at high load leads to reduced consumption or an increase in output) in full load and to realize an inlet valve near construction position for both systems.

The protection of the gasoline port injection before the gas exchange intake valve coking thus enables a reduced maintenance frequency of the gas exchange intake valves. At the same time, the injection of water allows the benefits of real driving emissions (RDE) and reduced fuel consumption in full load due to reduced enrichment of the combustion mixture.

Should only one system be used, the present invention can reduce the unit price of fuel injectors and fuel rails because both the water and gasoline injection components can be incorporated into a larger number of derivatives. If both systems can be installed, this system reduces the costs considerably, since one injector per cylinder can be omitted. This also has a positive effect on the weight of the motor vehicle.

Advantageous developments of the invention are described in the subclaims.

Both from a technical point of view and from a construction perspective, the distance A according to claim 2 is particularly preferred.

The embodiments according to claims 3 and 4 are two particularly preferred embodiments.

A third particularly preferred embodiment is given according to claim 5. In this variant, the space is further optimized.

Particularly preferably, the fluid according to claim 6 is water.

In the following the invention is explained in more detail with reference to four figures.

1 schematically shows a section through an internal combustion engine according to the invention.

2 shows a first particularly preferred exemplary embodiment.

3 shows a second particularly preferred embodiment.

4 shows a map for an operation of the internal combustion engine according to the invention.

1 schematically shows a section through an internal combustion engine according to the invention 1 with a cylinder 2 and with a gas delivery tract 3 and a gas exchange intake valve 4 between the cylinder 2 and the gas delivery tract 3 for controlling a gas exchange from the gas supply tract 3 in the cylinder 2 , A combustion chamber 15 in the cylinder 2 is limited by an unnumbered cylinder head roof, the cylinder 2 and a piston 14 and the gas exchange inlet valve 4 and a gas exchange exhaust valve 13 , which is an exhaust gas in the exhaust tract 12 escape. Next, the internal combustion engine 1 a first fuel injector 5 on, for introducing fuel from an in 1 not shown fuel supply 6 directly into the cylinder 2 and a second fuel injector 7 for introducing fuel from the fuel supply 6 in the gas supply tract 3 ,

According to the invention with the second fuel injector 7 a second fluid, preferably water, from one of the 2 and 3 illustrated fluid supply 8th in the gas supply tract 3 recoverable.

In a particularly preferred embodiment, the second fuel injector 7 at most ten times, preferably at most one to three times the inner diameter (Di) of the gas supply tract 3 from the gas exchange inlet valve 4 spaced apart. The inner diameter (Di) is shown schematically with two arrows, the distance (A) is also shown schematically with two arrows. The distance (A) is the distance from an unnumbered gas exchange intake valve seat of the gas exchange intake valve 4 to an injector tip of the second fuel injector 7 ,

2 shows a first preferred embodiment of the fluid supply for the internal combustion engine according to the invention 1 , Shown are a fuel supply 6 and a fluid supply 8th , each indicated by an arrow. Both the fuel supply 6 as well as the fluid supply 8th each lead into a single switching valve 10 and starting from the switching valve 10 opens the fuel / fluid mixture in a rail 9 and from there further illustrated by arrows tubes in three second fuel injectors 7 , The number of second fuel injectors 7 depends on the number of cylinders 2 the internal combustion engine 1 That is, it can also be four, five or six or even more second fuel injectors 7 be provided. The first embodiment is characterized in that between the fuel supply 6 and the second fuel injector 7 the rail 9 is arranged and the switching between fuel and fluid through the switching valve 10 in front of the rail 9 he follows.

3 schematically shows a second, particularly preferred embodiment of the fluid supply for the internal combustion engine according to the invention 1 , In this second particularly preferred embodiment, in turn, a fuel supply 6 and a fluid supply 8th schematically represented by arrows. In this embodiment is for the fuel supply 6 a separate rail 9 , a fuel rail, provided from which the fuel into three switching valves 11 empties. Next is for the fluid supply 8th a separate rail 9 , a fluid rail (water rail), provided, from which in turn the fluid in the three switching valves 11 empties. In front of these three switching valves 11 the fuel / fluid mixture continues into three second fuel injectors 7 , Also in this embodiment, that for each cylinder 2 the internal combustion engine 1 a separate second fuel injector 7 is provided.

The second, particularly preferred embodiment is thus distinguished by the fact that between the fuel supply 6 and the second fuel injector 7 a rail 9 is arranged and a switching between fuel and fluid in each case by a switching valve 11 between the rail 9 and the second fuel injector 7 he follows.

In a third particularly preferred embodiment, which is not shown figuratively, is the second fuel injector 7 a so-called two-substance injector, which is well known from the prior art.

For all embodiments, the fluid is preferably water.

4 schematically shows a map for an internal combustion engine according to the invention 1 , About a Y-axis an unspecified figured torque is shown, over an X-axis is an unspecified numbered speed of the internal combustion engine 1 shown.

How out 4 It can be seen takes place over the entire speed range of the internal combustion engine 1 At moderate torques only one intake manifold injection with the second fuel injector 7 with fuel.

In contrast, over the entire speed range of the internal combustion engine 1 At high torque, ie at full load, both a port injection with the second fuel injector 7 with fuel as well as a port injection with the second fuel injector 7 with the fluid, more preferably water.

Throughout the map there is a simultaneous fuel injection with the first fuel injector 5 directly into the cylinder 2 instead of.

In other words:
In order to circumvent the problems mentioned above, according to the invention, a fuel port injection and a water intake manifold injection and a fuel injection directly into the cylinder 2 proposed, which are combined, with both media are injected via an injector in the intake manifold. This injector is protected by suitable coatings against corrosion by water. For this, the existing know-how on the part of injector manufacturers in the field of E100 fuels and SCR (Selective Catalytic Reduction) can be used.

For this purpose, two different Verschaltungsvarianten be proposed.

In the first variant, the second fuel injector 7 only by a single rail 9 supplied and the switching of the media takes place directly in front of the rail 9 , In this case, however, a larger volume must be flushed between the two media during a switching process before the desired medium can be injected. This could pose a challenge to the application. On the other hand, so can the number of switching valves 10 be reduced. This variant would have to be executed as a parallel non-return media path, since otherwise there is a risk that water passes through the return in the fuel tank, or in the high pressure path.

In the second variant, the media supply of the second fuel injector takes place 7 over two rails 9 (Fuel and water), between which immediately before the second fuel injector 7 each by means of a switching valve 11 can be switched. When switching between the two media, only a very small volume of another medium needs to be flushed through the injector housing. This has significant advantages in stationary journeys. Furthermore, it has the advantage that it can be integrated into the existing fuel path directly in front of the high-pressure pump.

LIST OF REFERENCE NUMBERS

1

Internal combustion engine

2

cylinder

3

Gas supply row

4

Gas exchange inlet valve

5

first fuel injector

6

Fuel supply

7

second fuel injector

8th

fluid supply

9

Rail

10

switching valve

11

switching valve

12

exhaust tract

13

Gas exchange outlet valve

14

piston

15

combustion chamber

16

Rail

di

Inner diameter

A

distance

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 patent literature

• WO 2008/095783 A2 [0002]
• DE 102009044160 A1 [0004]
• EP 2789839 A2 [0006]
• EP 2657502 B1 [0007]

Claims (6)

Internal combustion engine ( 1 ) with at least one cylinder ( 2 ) and with a gas supply tract ( 3 ) and a gas exchange inlet valve ( 4 ) between the cylinder ( 2 ) and the gas supply tract ( 3 ) for controlling a gas exchange from the gas supply tract ( 3 ) in the cylinder ( 2 ) and with a first fuel injector ( 5 ) for introducing fuel from a fuel supply ( 6 ) directly into the cylinder ( 2 ) and with a second fuel injector ( 7 ) for introducing fuel from the fuel supply ( 6 ) into the gas delivery tract ( 3 ), characterized in that with the second fuel injector ( 7 ) a second fluid from a fluid supply ( 8th ) into the gas delivery tract ( 3 ) can be introduced. Internal combustion engine according to claim 1, characterized in that the second fuel injector ( 7 ) at most ten times, preferably at most one to three times the inner diameter (Di) of the gas feed tract ( 3 ) of the gas exchange inlet valve ( 4 ) spaced (A) is arranged. Internal combustion engine according to claim 1 or 2, characterized in that between the fuel supply ( 6 ) and the second fuel injector ( 7 ) a rail ( 9 ) and a switching between fuel and fluid through a switching valve ( 10 ) takes place in front of the rail. Internal combustion engine according to claim 1 or 2, characterized in that between the fuel supply ( 6 ) and the second fuel injector ( 7 ) a rail ( 9 ) and a switching between fuel and fluid through a, switching valve ( 11 ) between the rail ( 9 ) and the second fuel injector ( 7 ) he follows. Internal combustion engine according to claim 1 or 2, characterized in that the second fuel injector ( 7 ) is a bi-fuel injector. Internal combustion engine according to one of the claims 1 to 5, characterized in that the fluid is water.

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