Burner for a heater with improved fuel supply, improved heat shield and improved baffle plate

Abstract

A burner for a heater, especially for motor vehicles, has an essentially axially symmetrical combustion chamber, a burner nozzle for supply and atomization of fuel, a fuel needle for supplying fuel to the combustion chamber, a combustion air supply for supplying combustion air to the combustion chamber, a starting zone in which ignition of the fuel to start the burner takes place, a heat shield between the burner nozzle and the combustion chamber, the heat shield having openings for supplying secondary air to the combustion chamber, and a baffle plate located in the combustion chamber. By choosing the inside diameter of the fuel needle, the exit speed of the fuel is predetermined such that, during the starting phase of the burner; fuel in essentially unatomized form reaches the starting zone. The openings have air guide elements, and the baffle plate has a defined curvature in the axial direction.

1 . Burner for a heater, especially for use in motor vehicles, with
 an essentially axially symmetrical combustion chamber ( 22 ),   a burner nozzle ( 12 ) for supply and atomization of fuel, which has a fuel needle ( 14 ) for supplying fuel to the combustion chamber ( 22 ) and a combustion air supply ( 16 ) for supplying combustion air to the combustion chamber,   a starting zone ( 18 ) in which ignition of the fuel to start the burner takes place,   a heat shield between the burner nozzle and the combustion chamber, the heat shield having openings for supplying secondary air to the combustion chamber, and   a baffle plate which is located in the combustion chamber, wherein   the inside diameter of the fuel needle ( 14 ) is sized to produce a predetermined exit speed of the fuel such that, during the starting phase of the burner ( 10 ), fuel in essentially unatomized form reaches the starting zone ( 18 ),   the openings are equipped with air guide elements, and   the baffle plate has a defined curvature in an axial direction.   
   
   
       2 . Burner as claimed in  claim 1 , wherein the inside diameter of the fuel needle ( 14 ) is between 0.5 and 0.7 mm. 
   
   
       3 . Burner as claimed in  claim 1 , wherein the inside diameter of the fuel needle ( 12 ) is roughly 0.6 mm. 
   
   
       4 . Burner as claimed in  claim 1 , wherein the starting zone is made as a starting chamber ( 18 ) into which an ignition element ( 20 ) projects. 
   
   
       5 . Burner as claimed in  claim 1 , wherein the air guide elements are formed by tabs ( 28 ,  30 ) which are made integrally with the heat shield and which project toward the combustion chamber. 
   
   
       6 . Burner as claimed in  claim 5 , wherein the tabs ( 28 ,  30 ) are made at different angles relative to at least one of the surface of the heat shield and the radius of the heat shield ( 24 ). 
   
   
       7 . Burner as claimed in  claim 5 , wherein the tabs ( 28 ,  30 ) are grouped at essentially identical angles relative to at least one of the surface of the heat shield and the radius of the heat shield. 
   
   
       8 . Burner as claimed in  claim 1 , wherein the
 combustion chamber of the burner ( 10 ) has a burnout zone ( 32 ) and   wherein the secondary air is supplied to the burnout zone with a higher angular momentum than secondary air is supplied to the starting zone.   
   
   
       9 . Burner as claimed in  claim 1 , wherein the heat shield ( 24 ) has an opening ( 34 ) for routing the ignition element through. 
   
   
       10 . Burner as claimed in  claim 1 , wherein the curvature of the baffle plate ( 36 ) extends toward the burnout zone ( 30 ). 
   
   
       11 . Burner as claimed in  claim 1 , wherein
 an outer periphery of the baffle plate defines a plane and   wherein a ratio between a maximum axial distance of the baffle plate from said plane and the diameter of the baffle plate is between 0.07 and 0.21.   
   
   
       12 . Burner as claimed in  claim 11 , wherein the ratio between the maximum axial distance of the baffle plate ( 36 ) from the plane and the diameter of the baffle plate ( 36 ) is roughly 0.14.