DE10227810B4 - Burner for a heater with a baffle plate - Google Patents

Abstract

Burner for a mobile heater with a combustion chamber (14), in the combustion chamber (14) a fuel cone (24) can be sprayed and in the area of a flame a baffle plate (20) for accumulating the heat in the combustion chamber (14) is arranged, thereby characterized in that the baffle plate (20) has a non-point-symmetrical outer contour and its outer contour is adapted to the shell shape of the fuel cone (24).

Description

background the invention

The invention relates to a burner for a mobile heater with a combustion chamber in which a baffle plate is located in the area of a flame is arranged to accumulate the heat in the combustion chamber. Further The invention relates to a mobile heater for a vehicle with such Burner.

For burners of the type mentioned above baffle plates are used so that heat accumulates in the combustion chamber and thus the overall size of the combustion chamber and in particular their length can be reduced. The baffle is an obstacle to flow represents, which is generally transverse to the main flow direction of combustion air or fuel gases is arranged.

• – die Strömung in der Brennkammer kann umgelenkt und Turbulenzen können erzeugt werden, die ein Vermischen von Brennstoff und Brennluft begünstigen,
• – das Startverhalten kann verbessert werden, weil insbesondere so genannte „Totwassergebiete" geschaffen werden können, und
• – das Ausbrennverhalten kann, insbesondere bei nicht genügender Zerstäubung des Brennstoffs, verbessert werden, weil nicht verdampfte Brennstofftröpfchen der Strömungsumlenkung an der Prallscheibe nicht folgen können und daher auf die Prallscheibe auftreffen.

The following effects can be achieved with the help of a baffle plate:

• The flow in the combustion chamber can be redirected and turbulence can be generated which favors the mixing of fuel and combustion air,
• - The starting behavior can be improved because so-called "dead water areas" in particular can be created, and
• - The burnout behavior can be improved, in particular if the fuel is not atomized sufficiently, because unevaporated fuel droplets cannot follow the flow deflection on the baffle plate and therefore strike the baffle plate.

Out DE 10019 198 A1 and DE 100 39 152 A1 Generic atomizer burners are known in which a baffle or a baffle plate is arranged transversely in front of a nozzle body in a combustion chamber.

Out DE 42 18 629 A1 a combustion chamber is known, in particular for a particle filter regeneration in a motor vehicle exhaust system, in which a baffle plate is arranged in the interior of the combustion chamber.

Out DE 33 41 305 A1 a gasification oil burner with a baffle plate is known, which is arranged at the end of a flame tube and is provided for generating a heat build-up.

Out EP 0 922 594 A2 a vehicle heater with an evaporation burner is known in which three eccentric opening elements are arranged in succession in a combustion chamber.

Out DE 295 11 384 U1 An evaporation burner is known for a heating device operated with liquid fuel, in which different eccentric positions of a flame pinhole opening of unchanged area should lead to considerably different emission and noise values. The opening of a flame pinhole is formed eccentrically to the opening of an inner tube formed by a baffle edge of a baffle plate, the radially larger edge surface of the flame pinhole being circumferentially adjacent to a fuel introduction point.

Out DE 1 257 396 C. an atomizer burner operated with liquid fuel for heating devices is known in which a housing acting as a displacer is arranged concentrically in a pre-combustion chamber.

In known heaters can there are droplets of fuel which atomized in the combustion chamber have been burned through the combustion chamber and with conveyed the exhaust gas out of this become. Because of such unburned fuel droplets the exhaust emission of known heaters under certain operating conditions still insufficiently high.

The invention is based, which to avoid mentioned disadvantages and in particular a heater with a to create the burner described above, its exhaust gas emission on inexpensive Way is reduced.

Solution according to the invention

This object is achieved according to the invention with a burner mentioned at the outset, in which the baffle plate has a non-point-symmetrical outer contour and its outer contour is adapted to the shape of the shell of the fuel cone. The object is also achieved with a burner mentioned at the outset, in which the combustion chamber is essentially cylindrical, in particular circular-cylindrical, with an axis, the baffle plate has an outer contour that extends from an inner lateral surface of the combustion chamber 14 ) is spaced apart, and has a cross-sectional area whose center of gravity is offset from the axis and whose outer contour is adapted to the shape of the shell of the fuel cone. Finally, the task is also solved with a mobile heater for a vehicle with such a burner.

The invention is based on the knowledge that it with known heaters asymmetrical atomization due to various causes Fuel comes in the combustion chamber. According to the invention will not asymmetrical atomization even fixed what is relatively expensive would be, but the problem of an insufficient Exhaust emissions are solved by a newly designed baffle plate.

The baffle plate according to the invention is asymmetrical in cross section or the center of gravity is offset from an axis of the combustion chamber. The baffle plate designed in this way flows through the combustion chamber combustible gases against a novel and different over the peripheral region of the combustion chamber, which leads to the fact that almost all the atomized fuel is sprayed against the baffle plate and evaporates there.

The heater according to the invention therefore has improved overall Exhaust emission values.

The solution according to the invention is moreover very inexpensive and can for different types of heaters and combustion chambers can be varied in a simple manner.

Particularly good emission values can be achieved with a Torch can be achieved in which the outer contour of the baffle plate essentially an enlargement of a Cross section corresponds to the shell shape of the fuel cone.

advantageous Developments of the invention

With an advantageous further education According to the invention, the baffle plate has an essentially circular outer contour on. Such a baffle is known in principle, it is according to the invention arranged offset to the axis of the combustion chamber. The area focus the cross sectional area of the Baffle is not in the middle of the combustion chamber, but is outside arranged by this.

Alternatively or additionally in the burner according to the invention a fuel cone or spray is sprayed into the combustion chamber, the outer contour of the jacket the baffle plate according to the invention is adjusted. In such a burner is in a first Step optimized the fuel cone of the fuel to be injected and subsequently the baffle plate with its outer contour adapted to the shape of the spray. This step-by-step procedure is simplified the optimization process significantly.

The above cross sections extend each normal to the axis of the combustion chamber.

Summary of the drawings

An exemplary embodiment of a burner according to the invention based on the attached schematic drawings closer explained. It shows:

1 a greatly simplified longitudinal section of a combustion chamber of a burner according to the prior art for a mobile heater,

2 the cross section II-II according 1 .

3 a greatly simplified longitudinal section of a combustion chamber of a burner according to the invention for a mobile heater and

4 the cross section IV-IV according 3 ,

detailed Description of the embodiment

In 1 and 2 is a flame tube 10 of a further not shown known burner of a mobile heater for a vehicle auxiliary heater illustrated in longitudinal section. The flame tube 10 is along an axis 12 designed circular cylindrical and delimits a combustion chamber inside 14 ,

In the combustion chamber 14 is located at the 1 left side a nozzle body or atomizer 16 the burner, which is designed as an atomizing burner.

On the nozzle body 16 liquid fuel is sprayed in and carried away by combustion air. The fuel atomizes at the nozzle assembly 16 , is ignited there and flows as fuel gas along one in 1 with arrows 18 illustrated main flow direction in the flame tube 10 along the axis 12 from the related to 1 left to right.

In the flame tube 10 is across the axis 12 and essentially transverse to the main flow direction 20 a circular baffle 20 with the help of mounting feet, not shown, on the inner surface of the flame tube 10 attached.

The baffle 20 serves to accumulate the fuel gases and the heat carried in them in the flame tube 10 , Because of this heat-accumulating effect of the baffle plate 20 can the flame tube 10 and thus the burner overall in the direction of the axis 12 be relatively short.

The baffle 20 known heater is in cross section to the axis 12 Point-symmetrical with a circular outer contour and inside the flame tube 10 centrally located, ie it is symmetrical to the flame tube 10 and the distance between its outer contour and the inner wall of the flame tube 10 is constant over its entire scope. This arrangement of the baffle 20 is particularly in 2 illustrated.

In 3 and 4 A burner according to the invention is shown, with regard to the components 10 to 16 like the burner according to 1 and 2 is constructed.

According to the burner 3 and 4 is however a baffle 20 trained according to the cross section 4 has an essentially egg-shaped, non-point-symmetrical outer contour, the center of its area 22 to the axis 12 is offset (see in particular 4 ).

In the burner according to 3 and 4 the fuel is on the nozzle body 16 in a fuel cone or spray 24 sprayed in the in 4 cross section shown also essentially has an egg shape. The outer contour of the baffle plate 20 according to the 3 and 4 is on this form of spray 24 customized. The outer contour corresponds in particular to an enlargement of a cross section of the lateral surface of the fuel cone 24 as he is in 4 is illustrated.

Thanks to the asymmetrical baffle plate 20 is along its circumference a changing distance between the outer contour of the baffle plate 20 and the inner surface of the flame tube 10 educated. This changing distance leads to a different accumulation effect along the circumference of the baffle plate 20 and moreover, almost everything on the nozzle body is achieved 16 sprayed fuel against the baffle 20 blown and ignited there.

10

flame tube

12

axis

14

combustion chamber

16

nozzle body

18

Main flow direction the combustion air

20

baffle plate

22

Centroid

24

fuel cone

Claims (5)

Burner for a mobile heater with a combustion chamber ( 14 ), in the combustion chamber ( 14 ) a fuel cone ( 24 ) can be sprayed and a baffle plate in the area of a flame ( 20 ) to build up the heat in the combustion chamber ( 14 ) is arranged, characterized in that the baffle plate ( 20 ) has a non-point-symmetrical outer contour and its outer contour to the shell shape of the fuel cone ( 24 ) is adjusted. Burner for a mobile heater with a combustion chamber ( 14 ) that are essentially cylindrical to an axis ( 12 ) is designed in which a fuel cone ( 24 ) can be sprayed and in which a baffle plate in the area of a flame ( 20 ) to build up the heat in the combustion chamber ( 14 ) is arranged, characterized in that the baffle plate ( 20 ) has an outer contour that extends from an inner lateral surface of the combustion chamber ( 14 ) is spaced apart, and has a cross-sectional area, the centroid of which is to the axis ( 12 ) is offset, and that the outer contour of the baffle plate ( 20 ) to the shell shape of the fuel cone ( 24 ) is adjusted. Burner according to claim 2, characterized in that the baffle plate ( 20 ) has an essentially circular outer contour. Burner according to claim 1 to 3, characterized in that the outer contour of the baffle plate ( 20 ) essentially an enlargement of a cross section of the shell shape of the fuel cone ( 24 ) corresponds. Mobile heater for a Vehicle with a burner according to one of claims 1 to 4.