DE102008022585A1 - Internal combustion engine, particularly for motor vehicle, has working cylinder, in which combustion chamber is formed limited by working cylinder, and cylinder head is provided, which limits working cylinder and its combustion chamber - Google Patents

Abstract

The internal combustion engine has a working cylinder (10), in which a combustion chamber (18) is formed limited by a working cylinder. A cylinder head (20) is provided, which limits the working cylinder and its combustion chamber. An ignition chamber (22) is formed in the cylinder head for each working cylinder. A fluid flow channel is arranged and formed in a lateral wall of the ignition chamber on one end of the ignition chamber facing one of the combustion chambers of the working cylinder. An independent claim is included for a method for cold-starting of an internal combustion engine, particularly of a motor vehicle.

Description

The The invention relates to an internal combustion engine having at least one Working cylinder, in each case a combustion chamber of one in the working cylinder movable working piston is formed limited, and with a Cylinder head, which the working cylinders and their combustion chambers limited, wherein in the cylinder head for each working cylinder an ignition chamber is formed, wherein at least one fluid flow channel is provided, which the ignition chamber with the respective Combustion chamber of the working cylinder associated with this ignition chamber connects, according to the preamble of claim 1. The invention further relates to an internal combustion engine with at least a working cylinder, in each of which a combustion chamber of a in the working cylinder movable working piston is limited, and with a cylinder head, which the working cylinder and its Limited combustion chambers, wherein in the cylinder head for every working cylinder has an ignition chamber, according to the preamble of claim 17. The invention further relates to an internal combustion engine with at least a working cylinder, in each of which a combustion chamber of a in the working cylinder movable piston designed limited is, and with a cylinder head, which the working cylinder and whose combustion chambers are limited, being in the cylinder head for each Working cylinder is formed an ignition chamber, according to the The preamble of claim 26. The invention further relates a method for cold starting an internal combustion engine, in particular a motor vehicle, with at least one working cylinder in which each a combustion chamber of a movable in the working cylinder Working piston is limited, and with a cylinder head, which the working cylinder and its combustion chambers are limited, in the cylinder head for each cylinder an ignition chamber is formed, wherein in the ignition chamber an active ignition aid is arranged, with fuel injected into the ignition chamber is, according to the preamble of the claim 39th

Conventional combustion processes for internal combustion engines with indirect injection have the following disadvantages compared to direct injection: High thermal load on the cylinder head, loss of efficiency due to large wall heat transfer (piston + chamber), loss of efficiency due to aborted burnout in the cylinder, efficiency loss due to high flow losses in the firing channel, increased particulate matter and HC Emissions, since the combustion takes place near the wall. In contrast, there are the following advantages: Higher liter capacity (kW / l) for a given charge pressure, as a lower excess air is mobile, lower NO _x emissions through split combustion process, lower charge exchange work through filling channels, so that a larger speed range can be covered, low noise emissions and lower peak pressure.

known Vor- and vortex chamber motors have the following disadvantages: Unknown Entflammungsort; Ignition near the firing channel opening; Ignition by contact with hot combustion chamber wall; height Heat losses due to cooled chamber and long Shot channels; low volume to surface ratio; Flow losses.

Adiabatic engines known in the prior art have the disadvantage of a low degree of delivery, a reduced cylinder charge and a low specific power with simultaneously high NO _x emissions. The advantage of adiabatic engines is theoretically a high indexed efficiency and low wall heat losses.

at known internal combustion engines with ignition chamber arise with regard to the cold start behavior the following disadvantages: long start time, because large thermally inert mass is present. A large surface to be heated. They are high Compaction conditions necessary. It is a low air turbulence available. A small mixture processing energy through the injection system. It will only be a single injection for used the cold start.

From the US 2003/0183192 A1 is an internal combustion engine with an ignition chamber, a fuel injector into the ignition chamber injection device and known with a piston with piston recess, wherein injection device, ignition chamber and piston recess are arranged coaxially to each other and centerline.

From the EP 0 514 643 B1 is a cylinder head for a multi-cylinder internal combustion engine with combustion chambers formed in working cylinders known, wherein an antechamber with impact pin is arranged in the cylinder head. In the lateral wall of the pre-chamber radially outwardly directed channels are provided at a combustion chamber of a working cylinder end facing. Furthermore, an active ignition aid is provided in the form of a glow plug, which projects into the prechamber.

From the DE 35 38 633 A1 is a cylinder head with a prechamber known, wherein protrudes into the antechamber glow plug.

From the DE 690 09 116 T2 For example, a vortex chamber of the cyclone type in an internal combustion engine with thermal insulation is known. This should reduce cooling water loss to a minimum.

From the DE 195 19 713 A1 a device for controlling a heating element, such as a glow plug of an internal combustion engine is known, wherein the heating element is activated when a door contact is actuated.

From the DE 42 23 954 C1 a device for controlling a heating element, such as a glow plug of an internal combustion engine of a motor vehicle is known, wherein the heating element is activated when a buckle is engaged.

From the DE 41 21 520 C2 a circuit arrangement for preheating ignition devices in the manner of glow plugs for a motor vehicle driving internal combustion engine with a device for triggering the preheating is known, the device having a non-contact sensor and a cooperating with the sensor switch. Here, the sensor and the switch form a unit, wherein the switch is designed as a non-contact sensor and is arranged in the interior of the motor vehicle, that the presence of a person on the driver's seat can be scanned.

Of the Invention is the object of an internal combustion engine of o. g. Type with regard to the pushing out of the charge from the ignition chamber into the combustion chamber, the place of ignition in the ignition chamber, the wall losses in the ignition chamber and the cold start behavior to improve.

These The object is achieved by an internal combustion engine the o. g. Art with the marked in claims 1, 17 and 26 respectively Features and by a method of o. G. Kind of claim 39 marked features solved. Advantageous embodiments The invention are described in the further claims.

To it is in an internal combustion engine o. g. Type according to claim 1 according to the invention provided that in a side wall the ignition chamber at a combustion chamber of the working cylinder facing the end of the ignition chamber at least one fluid flow channel is arranged and designed such that a central longitudinal axis this fluid flow channel an at least approximately Secante with respect to the inner wall of the working cylinder forms, wherein the secant from a central longitudinal axis of the working cylinder is spaced.

This has the advantage that during a compression stroke of the working piston, in which a portion of the cylinder charge is pushed into the ignition chamber, in the ignition chamber, a directed, helical gas flow or a swirl flow and after ignition in the ignition chamber, the charge from the ignition chamber in the combustion chamber is pushed out with only a small wall contact. The at least one fluid flow passage acts as a firing channel which creates a high level of turbulence in the combustion chamber when the piston geometry allows a large free jet length. As a result, the charge in the combustion chamber burns away from the wall of the working cylinder, so that wall heat losses are minimized. At the same time, high turbulences promote low soot formation or soot burn-up. Due to the rich pre-combustion in the ignition chamber, a lower NO _x emission is achieved. The overflowing from the ignition chamber into the combustion chamber fuel-air mixture is already partially oxidized, which causes a lean combustion in the combustion chamber with lower combustion temperatures. This results in a high inert gas mass with high heat capacity (EGR content) and thus a lower NO _x - and soot formation. In addition, short shot channels result with correspondingly low wall heat losses.

Around to optimally detect the volume above the working piston is the at least one fluid flow channel is arranged in such a way and is formed such that the central longitudinal axis of the fluid flow channel perpendicular or tilted to the central longitudinal axis the working cylinder is aligned, that a combustion chamber side opening the fluid flow channel aligned towards the working piston is.

Conveniently, a fuel injection device is provided which is such arranged and designed that this fuel into the ignition chamber injects, wherein preferably the working piston has a piston recess, which is for example designed such that this 25% to 50% of Combustion chamber includes. This configuration is special advantageous if ignition chamber, fuel injection device and piston recess are arranged coaxially with each other.

Conveniently, the fuel injection device comprises an injection nozzle, designed as Mehrlochdüse or Einlochdüse is, wherein preferably the injection nozzle is formed is that this is a conical injection jet with generated an opening angle 0 ° to 10 °, so that a free jet length in the ignition chamber, d. H. a distance before the injection jet an inner wall of the Ignition chamber hits, is maximum. A narrow angle is special prefers.

In a preferred embodiment is a Volume of the ignition chamber 25% to 50% of a compression volume the associated working cylinder.

Conveniently, the at least one fluid flow channel is arranged and out forms that the central longitudinal axis of the fluid flow channel is arranged in a plane perpendicular to the central longitudinal axis of the working cylinder or tilted to a plane perpendicular to the central longitudinal axis of the working cylinder.

For a particularly effective generation of a swirl flow, are several, in particular four or six, fluid flow channels formed, preferably in the circumferential direction uniformly spaced apart from each other.

Especially low flow losses are achieved by the fact that the at least one fluid flow channel formed with an inlet edge rounding and / or the at least one fluid flow channel is conical is trained.

A greatest possible flexibility with regard to Fuel supply is achieved by having a fuel injection system for injecting fuel into the ignition chamber is, wherein the fuel injection system is a storage injection system, in particular a CR system (common rail), is.

In an exemplary embodiment are in the direction of Center longitudinal axis two rows of fluid flow channels one above the other arranged.

One Interlocking of the fluid flow channels emerging jets with improved mixture formation can be achieved in that the fluid flow channels of the one Row stronger in the direction of the central longitudinal axis are inclined as the fluid flow channels of the other series.

Farther it is in an internal combustion engine o. g. Type according to claim 17 inventively provided that on a floor the ignition chamber, which faces the combustion chamber, a Ignition aid is arranged such that this ignition aid protrudes into the ignition chamber.

This has the advantage of having a defined location of ignition within the ignition chamber is achieved.

For example the ignition aid is designed as a passive ignition aid.

Conveniently, the ignition aid is designed and arranged such that this one impact area for one in the ignition chamber Injected fuel is formed.

In a preferred embodiment, the ignition aid, the ignition chamber, a fuel injection device, which is arranged and designed such that this fuel in the ignition chamber is injected, and a piston recess in the Working piston arranged coaxially with each other.

A Reduction of thermal mass with correspondingly faster heating the ignition aid is achieved by the fact that the ignition aid with a separated from the interior of the ignition chamber Volume, in particular in the form of a cavity or one with a thermally insulating material filled cavity, and / or designed as a tube made of a thermally insulating material is.

A sufficiently large, thermally inert mass with safer Ignition is achieved by the fact that the ignition aid is formed with such a mass that during a compression phase of the working piston a temperature drop the ignition aid is avoided.

In A preferred embodiment is the ignition aid as a firing hat, especially in the form of a bell or a Cuboid, trained.

a far above or away from firing channels of the ignition chamber obtained in the combustion chamber location of flame obtained by the fact that the ignition aid is designed with a firing pin, which is from the bottom of the ignition chamber or the ignition aid away into the ignition chamber rises. This will be a Maximum of unburned fuel through the shot channels pushed into the combustion chamber.

low Turbulence with correspondingly low thrust losses when pushing fuel from the ignition chamber into the combustion chamber achieved by the fact that the ignition aid at the bottom of the ignition chamber is formed flow-conducting such that the ignition aid a directed towards the bottom of the ignition chamber flow deflects in the direction of a wall of the ignition chamber. Furthermore becomes through the ignition aid a flow stabilization achieved in the chamber.

Farther it is in an internal combustion engine o. g. Type according to claim 26 according to the invention provided that a wall the ignition chamber at least in a predetermined range with respect to the cylinder head is formed thermally insulated.

This has the advantage that high wall temperatures in the ignition chamber, which avoid unwanted coking can be achieved.

In a preferred embodiment, the thermal insulation is formed such that the wall of the ignition chamber of a thermally insulating material, in particular of ceramic, silicon nitride, zirconium oxide, a material with austeniti scheme structure, Nimonic, Inconel, or a material based on Ni or Co-based alloy is formed.

For example the thermal insulation is designed such that between the wall of the ignition chamber and the cylinder head an insulating material, in particular diatomaceous earth, or a ceramic material is arranged.

Conveniently, the thermal insulation is designed such that between the wall of the ignition chamber and the cylinder head a gap is trained.

For example the gap is formed as a closed space. The gap is For example, evacuated or with a heat-insulating Fluid, in particular a heat-insulating gas, in particular Air, filled.

In In an alternative embodiment, the gap is open Air gap formed, the air gap in the direction of the combustion chamber is open.

Thereby, that an injection nozzle is arranged and formed in this way is that the injector fuel into the ignition chamber injected, wherein in the cylinder head adjacent to the injection nozzle a cooling water channel is arranged such that this Cooling water channel a predetermined section on one of the ignition chamber facing away from the injection nozzle cool, further in the cylinder head adjacent to the injection nozzle a heat shield is arranged and configured such that it Heat shield a predetermined section on one of the ignition chamber facing the end of the injection nozzle of one of the ignition chamber outgoing heat radiation shields, on the one hand overheating the Injector prevents and on the other hand, a cooling the ignition chamber or the wall of the ignition chamber due to heat radiation in the direction of the injection device, which by the water cooling of the injector would be even more, reduced.

Conveniently, The heat shield has a portion which extends into the ignition chamber extends and a portion of a nozzle tip of the injector thermally shielded from the interior of the ignition chamber. This allows additional thermal discharge the injection nozzle, so if necessary, further cooling measures can be omitted.

A Coking of the area between the thermal insulating section the heat shield and the nozzle tip is thereby effective avoided that in the area between this section and the nozzle tip a seal is provided.

Farther it is in a method of o. g. Type according to claim 35 according to the invention provided that before the cold start the active ignition aid is preheated and during the Kaltstartens the internal combustion engine with increasing speed until reaching a predetermined idle speed during a compression stroke of the piston at least one pilot injection of fuel into the ignition chamber and this pre-injected fuel in the ignition chamber by means of the active ignition aid ignited, wherein after completion of at least one Pre-injection is a main injection.

This has the advantage that during a cold start the main injection in a well pre-conditioned ignition chamber with hot Residual gas takes place, so that an ignition delay is reduced and misfiring can be avoided.

to Adaptation of the cold start process to the respective ignition chamber, two or more pilot injections are made with the same or different amount of fuel.

Around To reduce power and fuel consumption will be after reaching idle speed deactivates the active ignition aid. Possibly. is annealed at very low engine temperatures.

For example is the preheating of the active ignition aid when pressed a door contact of a equipped with the internal combustion engine Motor vehicle and / or when detecting a person on a driver's seat a motor vehicle equipped with the internal combustion engine activated.

In In a preferred embodiment, the ignition aid, especially cylinder selective, deactivated if a value for engine temperature, smoothness, rotational nonuniformity, the ignition delay, a water temperature, an oil temperature and / or start of combustion exceeds a predetermined threshold value. or below.

The The invention will be explained in more detail below with reference to the drawing explained. This shows in

1 a schematic representation of a first preferred embodiment of an internal combustion engine according to the invention with ignition chamber,

2 a schematic representation of a second preferred embodiment of an internal combustion engine according to the invention with ignition chamber,

3 a sectional view of the ignition chamber of the internal combustion engine according to 1 respectively. 2 .

4 a third preferred embodiment of an internal combustion engine according to the invention with ignition chamber in sectional view,

5 a fourth preferred embodiment of an internal combustion engine according to the invention with ignition chamber in sectional view,

6 a fifth preferred embodiment of an internal combustion engine according to the invention with ignition chamber in sectional view,

7 a sixth preferred embodiment of an internal combustion engine according to the invention with ignition chamber in sectional view,

8th a seventh preferred embodiment of an internal combustion engine according to the invention with ignition chamber in sectional view,

9 an eighth preferred embodiment of an internal combustion engine according to the invention with ignition chamber in sectional view,

10 A ninth preferred embodiment of an internal combustion engine with ignition chamber according to the invention in sectional view,

11 a tenth preferred embodiment of an internal combustion engine according to the invention with ignition chamber in sectional view and

12 an eleventh preferred embodiment of an internal combustion engine according to the invention with ignition chamber in a sectional view.

In the 1 shown, the first preferred embodiment of an internal combustion engine according to the invention comprises a working cylinder 10 , a working piston 12 which is in the working cylinder 10 oscillating up and down, an injection nozzle 14 , and a glow plug 16 , In the working cylinder 10 is from the working piston 12 and a cylinder head 20 a combustion chamber 18 limited. In the cylinder head 20 is above the combustion chamber 18 an ignition chamber 22 formed, which by means of a Kammersitzringes 24 sealing in the cylinder head 20 is arranged and in the combustion chamber 18 protrudes into it. At a side facing away from the combustion chamber end of the ignition chamber 22 is the fuel injector 14 arranged which fuel in the form of a primary injection jet 26 into the ignition chamber 22 injects. At one of the combustion chamber 18 facing the end of the ignition chamber 22 are fluid flow channels or shot channels 28 as a flow-conducting connection between the interior of the ignition chamber 22 and the combustion chamber 18 such that a central longitudinal axis of this fluid flow channel forms a secant with respect to the inner wall of the working cylinder, wherein the secant is spaced from a central longitudinal axis of the working cylinder. An exemplary embodiment and arrangement of the shot channels 28 is out 3 seen. From these shot channels 28 flows fuel in the form of a secondary injection jet 32 from the interior of the ignition chamber 22 in the combustion chamber 18 , Both the glow plug 16 as well as the injector 14 protrude into the interior of the ignition chamber 22 into it. the working piston 12 has a piston recess 38 on.

In the 1 illustrated embodiment has an injection nozzle 14 with a large PV angle (beam cone angle). A value for ε is 18 and a value for σ is 0.25.

At the in 2 shown, second preferred embodiment of an internal combustion engine according to the invention functionally identical parts are identified by the same reference numerals, as in the first embodiment according to 1 so that their explanation to the above description of 1 is referenced. Also the ignition chamber 22 according to 2 has shot channels, as in 3 shown on. Unlike the first embodiment according to 1 is according to the second embodiment 2 a spark plug instead of a glow plug 30 intended.

The glow plug 16 or the spark plug 30 serve as a starting aid in the ignition chamber 22 , In the ignition chamber results in a charge layers with air and fuel mixture. The spark plug allows targeted initiation of combustion in the form of pre-combustion in the ignition chamber 22 , The pre-combustion in the ignition chamber 22 pushes the fuel over into the combustion chamber 18 in the working cylinder 10 , In the combustion chamber 18 of the working cylinder 10 followed by the main energy conversion.

This stage combustion with pre-combustion in the ignition chamber 22 Achieves a low emission performance with corresponding emission reduction with a 2-stage lean burn and low NO _x emissions even at high load. Engine related, there are the benefits of low engine load by a soft combustion and a peak pressure reduction, with a mean injection pressure requirement of less than 160 MPa, since the chamber equalizes and reduces the Zündverzüge different fuels.

At the in 4 illustrated, third preferred embodiment of an internal combustion engine according to the invention functionally identical parts are identified by the same reference numerals, as in the first and second embodiments according to 1 and 2 so that their explanation to the above description of 1 and 2 is referenced. Also the ignition chamber 22 according to 2 has shot channels 28 , analogous to in 3 shown, on, but instead of four shot channels six shot channels are provided. Furthermore, a nozzle cooling 34 intended. The central ignition chamber 22 is by means of an air gap 36 thermally from the cylinder head 20 isolated and screwed in.

As material for the ignition chamber 22 In all embodiments, for example, a Ni-base alloy is provided. This achieves oxidation resistance and low thermal conductivity.

The injector 14 , the ignition chamber 22 and the piston recess 38 lie on the same axis (coaxial) and preferably cylinder-centered. The shape of the ignition chamber 22 is ideally a sphere to achieve the largest possible volume to surface ratio. The ignition chamber volume is about 25 to 50% of the total compression volume of the working cylinder associated with this ignition chamber.

For a ball often enough space in the cylinder head 20 not from. Therefore, the ignition chamber 22 be easily stretched to a barrel or truncated cone shape, so that the primary injection jet 26 the longest possible free path without wall contact within the ignition chamber 22 can go back. The sealing surface between ignition chamber 22 and the combustion chamber 18 should be as close as possible to the combustion chamber roof, as the otherwise forming gap would become clogged with soot and an additional source of emissions will result. Any other type of sealing is possible.

The ignition chamber 22 has a series of openings in the form of the shot channels 28 the combustion chamber 18 above the piston with the interior of the ignition chamber 22 connect. The openings or shot channels 28 are approximately tangential to the inner chamber wall ( 3 ) arranged in the compression stroke of the working piston 12 the gas flow into the interior of the ignition chamber 22 to impart a directed helical flow (twist). The Zündkammerboden can be performed streamlined.

The openings or shot channels 28 are preferably additionally easy to the piston 12 inclined down to the volume 18 above the piston 12 Optimal to capture, similar to the spray holes of an injection nozzle. The openings or shot channels 28 are optionally designed by an inlet edge rounding and / or conicity such that the lowest possible flow losses. In this case, the flow from the ignition chamber 22 in the cylinder 10 or the combustion chamber 18 lower flow losses than vice versa. This makes sense because of the energy conversion in the ignition chamber 22 when flowing out higher pressure losses and consequently higher speeds occur.

In principle, any injection system is suitable which provides a sufficiently large mixture formation energy. A preferred system structure comprises a storage injection system (CR system - common rail), which offers the greatest possible flexibility in terms of design and application. Since these systems have the best availability, they represent the first choice. The injection nozzle is designed either as a multi-hole nozzle preferably with a small PV angle (opening angle of the cone spanned by the spray holes), which has values up to 0 °. The angle is preferably selected such that the free jet length or path length of the primary injection jet 26 in the ignition chamber 22 maximizes and wetting the side wall of the ignition chamber 22 is avoided. Optional is as injector 14 a Einlochdüse provided with a spray hole coaxial with the nozzle longitudinal axis 40 is trained. Alternatively, a non-throttling spigot nozzle as an injection nozzle 14 intended. Various injection system configurations are in 1 and 2 shown.

The combustion chamber 18 in the working cylinder 10 includes the piston recess 38 , The piston recess 38 has the largest possible diameter. Possible configurations are in 1 and 2 shown. The combustion in the working cylinder 10 takes place by the inventive arrangement largely without wall contact. This has the following advantages: A low thermal piston load with a resulting lower cooling effort; no combustion in narrow gaps or with wall contact, resulting in lower emission (HC + particle) emissions; better efficiency due to less cooling of the combustion zone (insulating air cushion); from the ignition chamber 22 through the openings or shot channels 28 flowing, partially burned charge can cause air in the working cylinder 10 quickly detect what will shorten the combustion time and achieve an efficiency gain; smallest possible valve pockets to avoid soot formation; the piston recess 38 in the area below the ignition chamber 22 is designed such that the harmful volume between the ignition chamber 22 and piston crown is as low as possible.

Since the piston bowl volume is smaller compared to a direct injection engine (about 25-50% of the working cylinder's compression volume 10 are in the chamber), the bowl depth is smaller. This allows a reduction in the compression height. The following advantages over a piston 12 with high bowl depth can be used individually or proportionally: extension of the connecting rod, so that results in a smaller push rod ratio; lower piston side forces with correspondingly less friction; lower personnel 2 , Order and thus better smoothness; Reduction of the (engine) block height with corresponding weight and resource savings; shorter piston with corresponding weight reduction and thus possible higher speeds or lower connecting rods and crankshaft load.

The Intake ducts can, compared to the diesel engine with direct injection, much stronger than filling channels be interpreted. This results in a better filling, especially at high speeds. This allows for a naturally aspirated engine a greater specific power, in a charged Motor either a larger power or a lowered boost pressure requirement. The reduced flow resistance reduce the charge exchange work, which lowers consumption.

Possibly the twist is due to a channel shutdown (swirl flap) in case of need raised. The unlocked channel then acts as a tangential channel and creates a twist in the cylinder.

With regard to the valve arrangement, a symmetrical arrangement of the elements in the cylinder head is preferred. Advantageously, a 3- or 4-valve arrangement with centrally installed ignition chamber 22 , Since only a small swirl level is required, the valves do not have to be flat but can also be slightly inclined or slightly radially installed and the charge channels can be designed for maximum filling. This allows larger valve cross-sections and more space for the ignition chamber 22 , If the valves are installed flat, so is the cylinder head 20 flat and it forms a combustion chamber 18 limited by the piston recess, a nip and the combustion chamber roof. If the valves installed inclined, so is a conical or spherical-shaped combustion chamber 18 prefers. The valves can be aligned normal to the combustion chamber (vertical) or twisted (parallel inlet and outlet valves) with the smallest possible valve pockets to the combustion chamber.

Below is a description a motor work game:

aspiration:

suck in the charge through filling channels; low swirl or tumble motion of the cylinder charge; Correspond to valve timing those of a standard diesel engine or are at maximum Filling optimized

Sealing:

Upon compression, cylinder charge is discharged from the combustion chamber 18 in ignition chamber 22 over the shot channels 28 pushed over; through the tangential to the ignition chamber 22 arranged shot channels 28 becomes a targeted charge movement in the ignition chamber 22 for example, generated with a helical ascending rotational movement. The charge movement in ignition chamber 22 is generated near the start of injection or start of combustion, which results in low dissipation.

Expand:

Ignition chamber: Near before or after TDC injection (pre and post injections possible). Pre and post injection quantities are adapted to the ignition chamber volume. Ignition on ignition aid 16 . 30 (Glow plug, spark plug, ignition cap, ignition chamber wall) or after ignition delay in air. Combustion under oxygen deficiency (fat burning). Pressure increase in the ignition chamber 22 with corresponding pushing out of the load in the working cylinder 10 ,

Cylinder: openings 28 between ignition chamber 22 and working cylinder 10 act as shot channels and generate a high level of turbulence (secondary injectors). The charge is due to the overflow in the working cylinder 10 or the combustion chamber 18 distributed. The shot channels 28 are aligned so that the charge as far away from the wall of the working cylinder 10 or the combustion chamber 18 burns. Low pressure increase in the cylinder, resulting in a smooth running engine with corresponding peak pressure reduction.

Emission advantages: Fat combustion in the ignition chamber 22 leads to low NO _x production. High turbulence during combustion in the working cylinder 10 leads to low soot formation and Rußabbrand is promoted, resulting in a high EGR compatibility of the combustion process. Low wall heat losses, low HC and particle formation due to combustion in a shallow depression 38 and not on cylinder or piston wall. Overflowing air-fuel mixture is due to the pre-combustion in the ignition chamber 22 already partially oxidized, resulting in a lean burn in the working cylinder 10 with correspondingly low combustion temperatures and high inert gas mass with high heat capacity (EGR content) leads. This achieves low NO _x - and soot formation.

The spatial arrangement of the ignition chamber 22 in the cylinder center combined with the inventive orientation of the shot channels results in the lowest possible wall heat losses. Short shot channels 28 also achieve low wall heat losses. The ignition chamber 22 preferably has a spherical, truncated cone, or barrel or cylinder stump-like shape (compact) in order to achieve a high volume to surface ratio. At the same time is the ignition chamber 22 so di dimensioned that the primary injection jet 26 has as long as possible free path. The air intake duct is optimized for filling and a flat piston with a large piston recess or a flat piston is provided.

The 5 to 9 show various embodiments of the ignition chamber 22 , which in each case between an inlet channel 42 and an exhaust duct 44 is arranged. According to the invention is at a combustion chamber 18 facing ground 46 the ignition chamber 22 , a starting aid 48 arranged such that this ignition aid 48 into the interior of the ignition chamber 22 protrudes into it.

To during the operation of the internal combustion engine with ignition chamber 22 a defined location of ignition in the ignition chamber 22 to achieve is the ignition aid 48 intended. This ignition aid 48 is designed and arranged such that it has an ignition in the ignition chamber 22 as far as possible above the firing channels 28 initiated to maximize unburned fuel from the ignition chamber 22 through the shot channels 28 in the combustion chamber 28 to push over. In order to define the location of the fire after a cold-start phase as fuel-efficient as possible, the ignition aid is provided 48 for example, as a firing hat, as in 5 to 9 represented, or similarly formed.

The ignition 48 forms an impact surface 50 for the primary injection jet. This area 50 is for example by an air gap insulation, double-walled construction with closed gas volume, from the chamber 22 isolated. As a result, the thermal mass of the ignition aid 48 reduced and it is ensured a quick heating. The impact area 50 is optionally a little thicker (sufficiently large thermally inert mass) to ensure that during the compression phase no unwanted temperature drop on the wall of the ignition aid 48 occurs ( 8th and 9 ).

By a patch tip "pimple", as in the embodiments according to the 5 to 7 As shown, the ignition location may be closer to the injector, depending on the combustion process requirement 14 be positioned. The "pimple" allows one in the ignition chamber 22 further up or away from the shot channels 28 lying ignition location. On the ground 46 the ignition chamber 22 is the ignition aid 48 with a streamlined edge 52 educated. This achieves lower flow losses and a more defined spin in the chamber.

The shape of the ignition aid 48 is preferably designed such that during the inflow and outflow, the flow is influenced and, for example, lower turbulence arise. This allows larger firing channel openings 28 with lower overshoot losses. This results in lower flow losses in the ignition chamber 22 and there is more energy for the mixture formation in the working cylinder 10 to disposal.

In the 5 is the ignition aid 48 as firing pin, in the 6 and 7 is the ignition aid 48 as a spiked helmet, in 8th is the ignition aid 48 as a "melon" and in 9 is the ignition aid 48 designed as a cylinder. The ignition aid 48 is preferably centered in the ignition chamber 22 arranged.

In the internal combustion engine according to the invention with an ignition chamber or vortex or vortex chamber 22 Parts of the engine are isolated, without sacrificing a loss of cylinder filling, as on a fully adiabatic engine. It is important that the combustion chamber 18 , the filling channels 28 and the piston 12 be cooled to ensure a high degree of delivery. The Zündkammerwände can have a high temperature, since there are no losses in the cylinder charge amount.

According to the invention, the ignition chamber 22 isolated against heat loss. For this purpose, the ignition chamber 22 For example, made of ceramic, such as silicon nitride or zirconium oxide, or a poorly heat-conducting metal or material (austenitic structure, for example, Nimonic, Inconel). Alternatively or additionally, the chamber is lined with an insulating compound, such as diatomaceous earth. Further alternatively or additionally, an air gap insulation 36 , like out 4 seen, provided. The air gap 36 is an example of a closed air gap 36 , ie a closed volume, or an air gap open to the combustion chamber 36 , All the above measures for thermal insulation can also be combined.

In a preferred embodiment, the ignition chamber 22 is made as thin-walled as possible so that it quickly reaches a predetermined operating temperature. The materials used are expediently heat-resistant.

The walls of the ignition chamber 22 are kept so hot by the insulation that the Leidenfrost temperature of the fuel is exceeded. As a result, no liquid drops can adhere to the wall. This prevents coke build-up in the ignition chamber 22 and promotes mixture formation.

How out 4 and 10 It can be seen in the area directly around the injection nozzle 14 a cooling 34 provided, for example, with cooling water, the injection nozzle 14 cools. Otherwise, the injector overheats 14 which can lead to failure by Düsenverkokung. How out 10 can be seen, the heat load as well as the heat Irradiation by shielding the nozzle 14 through a heat shield 52 at the nozzle 14 lowered. It also reduces the heat shield 52 the wall heat loss of the ignition chamber 22 , due to the nozzle cooling 34 , The heat shield 52 has a section 56 on, which is in the ignition chamber 22 extends into it and part of a nozzle tip 58 the injector 14 from the interior of the ignition chamber 22 thermally shielded.

Alternatively or in addition to the nozzle cooling 34 is a seal in the area between the section 56 and the nozzle tip 58 intended. This additionally reduces a heat input into the injection nozzle 14 , prevents coking of the gap between the section 56 and the nozzle tip 58 and creates a thermal discharge of the injector 14 , so that if necessary, the nozzle cooling 34 can be omitted.

The inventively formed adiabatic ignition chamber the following advantages are expected: efficiency advantages, since lower wall heat losses. Better vaporization of the fuel when injected by higher temperatures in the ignition chamber 22 , No coking of the combustion chamber walls, as the temperatures are above the Leidenfrost temperature of the fuel. Low thermal load on the cylinder head 20 , Greater smoothness due to short ignition delays. Low proportion of premixed combustion and thus low NO _x emissions.

According to the following procedure is provided during cold start: In order to minimize the ignition delay and to ensure a safe (cold) start, is in the ignition chamber 22 provided an electrically or laser-operated ignition aid. This is preferred as a glow plug 16 ( 1 ) or spark plug 30 ( 2 ) educated. The Vorglühvorgang of the engine, for example, begins with the actuation of a door contact to the ignition chamber 22 to be conditioned in advance. Another possibility for the preconditioning of the ignition chamber 22 is to start the engine conditioning when the driver of a motor vehicle equipped with the internal combustion engine according to the invention takes place on the driver's seat. This allows a faster engine start from the driver's point of view.

When the engine starts, it becomes a rail pressure in a fuel supply to the injector 14 built up to at least the minimum injection pressure. During the compression stroke is injected. For conditioning the ignition chamber 22 is one or more pilot injection quantities, which are adapted to the Zündkammervolumen and include different amounts, provided. The pilot injection quantities can be ignited as desired. As a result, the main injection takes place in a well preconditioned ignition chamber 22 with hot residual gas, which reduces the ignition delay. Mixture preparation and vaporization will be via the high injection pressure, the multiple injection as well as the helical air flow in the ignition chamber 22 favored. In addition, the turbulent air flow provides for quick evaporation of the fuel from the wall and provides an ignitable mixture of the electric ignition aid 16 . 30 ready. The ignition of the mixture takes place after the mixture preparation by auto-ignition or z. B. a spark of the spark plug 30 , This procedure repeats with increasing engine speed (startup phase) until idle speed is reached. In order to reduce the power consumption and therefore the fuel consumption during engine operation, the ignition can be initiated by means of a passive ignition aid (eg ignition cap) after the cold start procedure, and the active ignition aid can be switched off.

11 illustrates an embodiment of the invention, in which the seal between injector 14 and cylinder head 20 through an edge 60 in the cylinder head 20 is realized, wherein an end face of the injection nozzle 14 on this edge 60 is applied. A sealing ring 62 seals the firing hat 22 against the cylinder head 20 from. Below the sealing ring 62 is between the firing hat 22 and the cylinder head 20 A gap 70 educated. This sealing ring 62 serves as a support and seal and provides a low thermal conductivity available, so that an additional thermal relief is achieved. at 64 are flowed through by cooling medium channels and reference numerals 66 designates cylinder head bolts.

At the in 12 illustrated embodiment are at the combustion chamber 18 facing the end of the ignition chamber 22 a firing hat 68 and two rows of stacked shot channels 28 educated. The shot channels 28 the lower and upper rows are offset in the circumferential direction against each other. Here are the shot channels 28 the upper or the combustion chamber 18 turned away row towards the combustion chamber 18 tilted, leaving the shot channels 28 passing through emerging rays between each other. This achieves improved mixture formation.

10

working cylinder

12

working piston

14

injection

16

glow plug

18

combustion chamber

20

cylinder head

22

ignition chamber

24

Chamber seat ring

26

primary Injection jet

28

picking channels

30

spark plug

32

secondary Injection jet

34

nozzle cooling

36

air gap

38

piston bowl

40

nozzle axis

42

inlet channel

44

exhaust port

46

Bottom of the ignition chamber 22

48

ignition aid

50

incident

52

heat shield

54

central longitudinal axis

56

Section of the heat shield 52 which is in the ignition chamber 22 extends into it

58

injector cap

60

edge

62

seal

64

from Cooling medium flows through channels

66

Head Bolt

68

ignition cap

70

gap

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 2003/0183192 A1 [0006]
• - EP 0514643 B1 [0007]
• - DE 3538633 A1 [0008]
• - DE 69009116 T2 [0009]
• DE 19519713 A1 [0010]
• - DE 4223954 C1 [0011]
• - DE 4121520 C2 [0012]

Claims (44)

Internal combustion engine with at least one working cylinder ( 10 ), in each of which a combustion chamber ( 18 ) of one in the working cylinder ( 10 ) movable working piston is limited, and with a cylinder head ( 20 ), which the working cylinder ( 10 ) and their combustion chambers ( 18 ), wherein in the cylinder head ( 20 ) for each cylinder ( 10 ) an ignition chamber ( 22 ), wherein at least one fluid flow channel ( 28 ) is provided, which the ignition chamber ( 22 ) with the respective combustion chamber ( 18 ) of this ignition chamber ( 22 ) associated working cylinder ( 10 ), characterized in that in a side wall of the ignition chamber ( 22 ) at a combustion chamber ( 18 ) of the working cylinder ( 10 ) facing the end of the ignition chamber ( 22 ) at least one fluid flow channel ( 28 ) is arranged and formed such that a central longitudinal axis of this fluid flow channel approximately a secant with respect. The inner wall of the working cylinder ( 10 ), the secant from a central longitudinal axis ( 54 ) of the working cylinder ( 10 ) is spaced. Internal combustion engine according to claim 1, characterized in that the at least one fluid flow channel ( 28 ) is arranged and formed such that the central longitudinal axis of the fluid flow channel ( 28 ) perpendicular or tilted to the central longitudinal axis ( 54 ) of the working cylinder ( 10 ) is oriented such that a combustion chamber-side opening of the fluid flow channel ( 28 ) in the direction of working piston ( 12 ) is aligned. Internal combustion engine according to at least one of the preceding claims, characterized in that a fuel injection device is provided, which is arranged and designed such that this fuel into the ignition chamber ( 22 ) injects. Internal combustion engine according to claim 3, characterized in that the fuel injection device is an injection nozzle ( 14 ), which is formed as a multi-hole nozzle or Einlochdüse. Internal combustion engine according to claim 4, characterized in that the injection nozzle ( 14 ) is designed such that it has a conical injection jet ( 26 ) with an opening angle 0 ° to 15 °, in particular 0 ° to 10 °, generated. Internal combustion engine according to at least one of the preceding claims, characterized in that the working piston ( 12 ) a piston recess ( 38 ) having. Internal combustion engine according to claim 6, characterized in that the piston recess ( 38 ) is designed such that these 25% to 50%, in particular 25% to 95% of the combustion chamber ( 18 ) includes. Internal combustion engine according to one of claims 3 to 5 and claim 4 or 5, characterized in that ignition chamber ( 22 ), Fuel injection device ( 14 ) and piston recess ( 38 ) are arranged coaxially with each other. Internal combustion engine according to at least one of the preceding claims, characterized in that a volume of the ignition chamber ( 22 ) 20% to 50% of a compression volume of the associated working cylinder ( 10 ) is. Internal combustion engine according to at least one of the preceding claims, characterized in that the at least one fluid flow channel ( 28 ) is arranged and formed such that the central longitudinal axis of the fluid flow channel in a plane perpendicular to the central longitudinal axis ( 54 ) of the working cylinder ( 10 ) or tilted to a plane perpendicular to the central longitudinal axis ( 54 ) of the working cylinder ( 10 ) is arranged. Internal combustion engine according to at least one of the preceding claims, characterized in that four or six fluid flow channels ( 28 ) are formed, which are spaced approximately uniformly in the circumferential direction. Internal combustion engine according to at least one of the preceding claims, characterized in that the at least one fluid flow channel ( 28 ) is formed with an inlet edge rounding. Internal combustion engine according to at least one of the preceding claims, characterized in that the at least one fluid flow channel ( 28 ) is conical. Internal combustion engine according to at least one of the preceding claims, characterized in that a fuel injection system for injecting fuel into the ignition chamber ( 22 ), wherein the fuel injection system is a storage injection system, in particular a CR system (common rail). Internal combustion engine according to at least one of the preceding claims, characterized in that in the direction of the central longitudinal axis ( 54 ) two rows of fluid flow channels ( 28 ) are arranged one above the other. Internal combustion engine according to claim 15, characterized in that the fluid flow channels ( 28 ) of a number more in the direction of Mit angular axis ( 54 ) are inclined as the fluid flow channels ( 28 ) of the other row. Internal combustion engine with at least one working cylinder ( 10 ), in each of which a combustion chamber ( 18 ) of one in the working cylinder ( 10 ) movable working piston ( 12 ) is limited and with a cylinder head ( 20 ), which the working cylinder ( 10 ) and their combustion chambers ( 18 ), wherein in the cylinder head ( 20 ) for each cylinder ( 10 ) an ignition chamber ( 22 ), in particular according to at least one of the preceding claims, characterized in that on a floor ( 46 ) of the ignition chamber ( 22 ), which the combustion chamber ( 18 ), an ignition aid ( 48 ) is arranged such that this ignition aid ( 48 ) into the ignition chamber ( 22 ) protrudes into it. Internal combustion engine according to claim 17, characterized in that the ignition aid ( 48 ) is designed as a passive ignition aid. Internal combustion engine according to at least one of claims 17 or 18, characterized in that the ignition aid ( 48 ) is designed and arranged such that it has an impact surface ( 50 ) for one in the ignition chamber ( 22 ) forms injected fuel. Internal combustion engine according to at least one of claims 17 to 19, characterized in that the ignition aid ( 48 ), the ignition chamber ( 22 ), a fuel injection device ( 14 ), which is arranged and designed such that this fuel into the ignition chamber ( 22 ) and a piston recess ( 38 ) in the working piston ( 12 ) are arranged coaxially with each other. Internal combustion engine according to at least one of claims 17 to 20, characterized in that the ignition aid ( 48 ) with one of the interior of the ignition chamber ( 22 ) Separated volume, in particular in the form of a cavity or a filled with a thermally insulating material cavity, and / or is formed as a tube made of a thermally insulating material. Internal combustion engine according to at least one of claims 17 to 21, characterized in that the ignition aid ( 48 ) is formed with such a mass that during a compression phase of the working piston ( 12 ) a temperature drop of the ignition aid ( 48 ) is avoided. Internal combustion engine according to at least one of claims 17 to 22, characterized in that the ignition aid ( 48 ) is formed as a firing hat, in particular in the form of a bell or a cuboid. Internal combustion engine according to at least one of claims 17 to 23, characterized in that the ignition aid ( 48 ) is formed with a firing pin extending from the ground ( 46 ) of the ignition chamber ( 22 ) or the ignition aid ( 48 ) away into the ignition chamber ( 22 ) rises into it. Internal combustion engine according to at least one of claims 17 to 24, characterized in that the ignition aid ( 48 ) on the ground ( 46 ) of the ignition chamber ( 22 ) is designed flow-conducting such that the ignition aid ( 48 ) one in the direction of the ground ( 46 ) of the ignition chamber ( 22 ) directed flow in the direction of a wall of the ignition chamber ( 22 ) redirects. Internal combustion engine with at least one working cylinder ( 10 ), in each of which a combustion chamber ( 18 ) of one in the working cylinder ( 10 ) movable working piston ( 12 ) is limited and with a cylinder head ( 20 ), which the working cylinder ( 10 ) and their combustion chambers ( 18 ), wherein in the cylinder head ( 20 ) for each cylinder ( 10 ) an ignition chamber ( 22 ), in particular according to at least one of the preceding claims, characterized in that a wall of the ignition chamber ( 22 ) at least in a predetermined area with respect to the cylinder head ( 20 ) is formed thermally insulated. Internal combustion engine according to claim 26, characterized in that the thermal insulation is formed such that the wall of the ignition chamber ( 22 ) is formed of a thermally insulating material, in particular of ceramic, silicon nitride, zirconium oxide, a material with austenitic structure, Nimonic, Inconel, or a material based on Ni or Co-based alloy. Internal combustion engine according to at least one of claims 26 or 27, characterized in that the thermal insulation is designed such that between the wall of the ignition chamber ( 22 ) and the cylinder head ( 20 ) an insulating material, in particular diatomaceous earth, or a Kermikwerkstoff is arranged. Internal combustion engine according to at least one of claims 26 to 28, characterized in that the thermal insulation is formed such that between the wall of the ignition chamber ( 22 ) and the cylinder head ( 20 ) A gap ( 36 ) is trained. Internal combustion engine according to claim 29, characterized in that the gap ( 36 ) is designed as a closed space. Internal combustion engine according to claim 30, characterized in that the gap ( 36 ) evacuated or with a heat-insulating fluid, in particular a heat-insulating gas, in particular air, is filled. Internal combustion engine according to claim 29, characterized in that the gap ( 36 ) is designed as an open air gap. Internal combustion engine according to claim 32, characterized in that the air gap ( 36 ) in the direction of the combustion chamber ( 18 ) is open. Internal combustion engine according to at least one of claims 26 to 33, characterized in that an injection nozzle ( 14 ) is arranged and designed such that the injection nozzle ( 14 ) Fuel into the ignition chamber ( 22 ), wherein in the cylinder head ( 20 ) adjacent to the injection nozzle ( 14 ) a cooling water channel ( 34 ) is arranged such that this cooling water channel ( 34 ) a predetermined portion at one of the ignition chamber ( 22 ) facing away from the end of the injection nozzle ( 14 ) cools. Internal combustion engine according to at least one of claims 26 to 34, characterized in that in the cylinder head ( 20 ) adjacent to the injection nozzle ( 14 ) a heat shield ( 52 ) is arranged and designed such that this heat shield ( 52 ) a predetermined section on one of the ignition chamber ( 22 ) facing the end of the injection nozzle ( 14 ) from one of the ignition chamber ( 22 ) shields outgoing heat radiation. Internal combustion engine according to claim 35, characterized in that the heat shield ( 52 ) a section ( 56 ), which extends into the ignition chamber ( 22 ) and a part of a nozzle ( 58 ) of the injection nozzle ( 14 ) from the interior of the ignition chamber ( 22 ) shielded thermally. Internal combustion engine according to claim 36, characterized in that in the area between the section ( 56 ) and the nozzle tip ( 58 ) A seal is provided. Internal combustion engine according to at least one of claims 17 to 34, characterized in that the cylinder head ( 20 ) and crankcase are integrally formed with each other to a monoblock. Method for cold starting an internal combustion engine, in particular of a motor vehicle, which in particular after at least one of the preceding claims is formed, with at least one working cylinder, in each of which a combustion chamber of formed limited in a movable cylinder in the working piston is, and with a cylinder head, which the working cylinder and its Limited combustion chambers, wherein in the cylinder head for every working cylinder has an ignition chamber, wherein in the ignition chamber an active ignition aid is arranged, with fuel injected into the ignition chamber is characterized in that before the cold start the active Starting aid is preheated and while cold starting the internal combustion engine with increasing speed until reaching a predetermined idling speed during a compression stroke the piston at least one pre-injection of fuel in the Ignition occurs and this pre-injected fuel in the ignition chamber by means of the active ignition aid ignited, wherein after completion of at least one Pre-injection is a main injection. Method according to claim 39, characterized that two or more pilot injections with the same or different Fuel amount done. Method according to claim 39 or 40, characterized that after reaching the idle speed, the active ignition aid is deactivated. Method according to at least one of the claims 39 to 41, characterized in that the preheating of the active Ignition aid when a door contact is actuated a motor vehicle equipped with the internal combustion engine is activated. Method according to at least one of the claims 39 to 42, characterized in that the preheating of the active Ignition aid when detecting a person on a driver's seat a motor vehicle equipped with the internal combustion engine is activated. Method according to at least one of the claims 39 to 43, characterized in that the starting aid, especially cylinder selective, is deactivated when a value for engine temperature, smoothness, rotational nonuniformity, the ignition delay, a water temperature, an oil temperature and / or start of combustion exceeds a predetermined threshold value. or below.