Patent Application
20100155510
The present disclosure relates to a nozzle, and in particular to a nozzle including a trumpet portion.
Exhaust gas after treatment systems are commonly used in conjunction with diesel engines for reducing the amount of nitrous oxides (NOx) in an exhaust gas. One type of after treatment system includes an injector for spraying a reduction agent, such as ammonia, fuel or urea, into the exhaust gas. The exhaust gas is then transported to a catalytic converter, where the amount of nitrous oxides in the exhaust gas are reduced as the reduction agent reacts with the nitrous oxides in the exhaust gas to form water and nitrogen. After reacting in the catalytic converter, the exhaust gas is released from the catalytic converter to the atmosphere.
The injector typically includes an injector orifice, where the injector sprays the reduction agent out of the injection orifice. It may be beneficial in at least some after treatment systems to vary the pressure of the reduction agent at the injector orifice as the reduction agent is sprayed into an exhaust pipe. Spraying the reduction agent into the exhaust pipe at different pressures may result in a varied spray pattern. That is, the spray pattern of the injector changes depending on the pressure of the injector. More particularly, as the pressure in the injector orifice increases, the angular momentum of the reduction agent being sprayed out of the injector also increases. As a result of the increased angular momentum the reduction agent is sprayed at a higher angle into the exhaust pipe. Thus, varying the pressure at the injector orifice may result in a varied spray pattern of the reduction agent.
At least some exhaust pipes may be designed with the assumption that the injector will spray the reduction agent at a generally constant spray pattern, regardless of the pressure. Therefore, there exists a need for an injector that sprays the reduction agent from the injector orifice at varying pressures, while still maintaining a generally constant spray pattern.
Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed systems and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.
Moreover, a number of constants may be introduced in the discussion that follows. In some cases illustrative values of the constants are provided. In other cases, no specific values are given. The values of the constants will depend on characteristics of the associated hardware and the interrelationship of such characteristics with one another as well as environmental conditions and the operational conditions associated with the disclosed system.
In one example, the atomizer 20 may be a swirl type injector, and may include a needle 32, a needle guide 34, an atomizer inlet 36, an atomizer outlet 38, a swirl chamber 40, a biasing member 42, shown in the form of a spring, and a solenoid 44. The fluid 30 may be any fluid that can be atomized, and in one example the fluid 30 may be a fluid used in an exhaust gas after treatment system, such as, but not limited to, ammonia, fuel or urea. The atomizer outlet 38 includes a nozzle 50 extending along the axis A-A, where the fluid 30 may exit the atomizer 20 through the atomizer outlet 38 through the nozzle 50. The fluid 30 may then be sprayed into any predetermined location.
As the fluid 30 exits the atomizer 20 through the atomizer outlet 38, a spray pattern S may be created. The spray pattern S may be defined as the pattern of fluid spray as the fluid 30 exits the injector. The spray pattern S includes a series of fluid droplets that may be created as the fluid 30 is atomized by the atomizer 20. The spray pattern S may include a spray angle A.
The geometry of the trumpet portion 72 may be generally funnel-shaped. In one example, the trumpet 72 includes a generally cone shaped profile, where outer surfaces 76 of the trumpet are angled outwardly towards the exit portion 74. The outer surfaces 76 of the trumpet 72 may define a trumpet angle 80, where the trumpet angle 80 identifies the positions where the outer surfaces 76 are angled in respect to one another. In the example as illustrated in each of
The nozzle 50 may also include an innerfirst edge 82 and an opposing outer second edge 84 longitudinally spaced from first edge 82. The first edge 82 may be located between the orifice 62 and the trumpet 72, and the second edge 84 may be located at the exit portion 74. The first edge 82 may be created as the outer surface 70 of the orifice 62 transitions to the outer surfaces 76 of the trumpet 72. The second edge 84 may be created as the trumpet 72 terminates at the exit portion 74. The first edge 82 and the second edge 84 may define a trumpet height H. More specifically, in one example, the trumpet height H may be defined as the distance between the first edge 82 and the second edge 84. The trumpet height H may be greater than the orifice dimension D.
The spray pattern S may depend at least in part by the geometry of both the orifice 62 and the trumpet 72. That is, maintaining the trumpet angle 80 at less than ninety degrees and allowing the trumpet height H to be greater than the orifice dimension D may create certain flow characteristics of the nozzle 50. More specifically, the trumpet 72 may be included with the nozzle 50 for maintaining a generally constant spray pattern S (illustrated in
It may be advantageous to include a generally constant spray pattern S in at least some types of applications. For example,
Turning back to
In the examples as illustrated in
Turning to
Therefore, including the trumpet 72 with the nozzle 50 with the trumpet angle 80 less than ninety degrees and the trumpet height H greater than the orifice dimension D may be advantageous for at least several reasons. First, if the trumpet 72 is eliminated, the angle A of the spray pattern S may increase. Moreover, if the trumpet angle 80 is greater than ninety degrees, the trumpet 72 will not contact the fluid 30 and the angle A of the spray pattern may increase. Additionally, if the trumpet height H is not greater than the orifice dimension D, then the fluid 30 may not have adequate distance to travel in order for the fluid 30 to decrease velocity. As a result, the fluid 30 may not decrease in velocity sufficiently in order to exit the nozzle 50 at the spray angle A.
By maintaining the trumpet height H to be greater than the orifice dimension D, and by maintaining the trumpet angle 80 to be less than ninety degrees, even as the supply pressure of the fluid 30 entering the orifice 62 increases, the spray pattern S and the spray angle A will remain generally about the same. Although only two different supply pressures are illustrated in each of
A method of atomizing the fluid 30 is also disclosed, and is illustrated generally in
In step 204, the fluid 30 may be sprayed out of the nozzle 50 at the first supply pressure. As discussed above, the first supply pressure may be the pressure of the fluid 30 supplied to the orifice 62. When the fluid 30 is sprayed out of the nozzle 50 at the first supply pressure, the fluid 30 breaks contact with the nozzle 50 at the first edge 82, which is illustrated in
In step 206, the fluid 30 may be sprayed out of the nozzle 50 at the second supply pressure, where the first supply pressure may be less than the second supply pressure. When the fluid 30 is sprayed out of the nozzle 50 at the second supply pressure, the fluid breaks contact with the nozzle 50 at the second edge 84. In one example, the first supply pressure may be about 40 psi (275.8 kPa), and the second supply pressure may be about 100 psi (689.5 kPa). However, it should be noted that the geometry of the nozzle 50 may be adjusted for a range of acceptable supply pressures. Process 200 may then proceed to step 208.
In step 208, the fluid 30 may be sprayed out of the nozzle 50 at a third supply pressure. As discussed above, the third supply pressure may be different than the first supply pressure and the second supply pressure. When the fluid 30 is sprayed out of the nozzle 50 at the third supply pressure, the fluid 30 may break contact with the nozzle 50 at either of the first edge 82 or the second edge 84 or possibly between the edges along surface 76, which may depend on the value of the third supply pressure. More specifically, in one illustrative example if the third supply pressure may be greater than both of the first supply pressure and the second supply pressure, then the fluid 30 may break contact with the nozzle at the second edge 84. Alternatively, if the third supply pressure is less than both of the first supply pressure and the second supply pressure, then the fluid 30 may break contact with the nozzle at the first edge 82. Process 200 may then proceed to step 210.
In step 210, the spray angle S may be maintained as the fluid 30 is sprayed out of the nozzle 50. In other words, the spray angle S remains generally constant as the supply pressure of the fluid 30 varies. For example, the spray angle S may remain generally constant as the supply pressure varies between the first supply pressure, the second supply pressure and the third supply pressure. Process 200 may then terminate.
The present disclosure has been particularly shown and described with reference to the foregoing illustrations, which are merely illustrative of the best modes for carrying out the disclosure. It should be understood by those skilled in the art that various alternatives to the illustrations of the disclosure described herein may be employed in practicing the disclosure without departing from the spirit and scope of the disclosure as defined in the following claims. It is intended that the following claims define the scope of the disclosure and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the disclosure should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing illustrations are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.
