Abstract:
A system and/or method of controlling smoke or noise emanating from a diesel engine wherein a throttle is drivingly coupled to the diesel engine, and wherein an operator of the engine changes a throttle position. The system may comprise a high pressure fuel pump in fluid communication with a fuel reservoir, a fuel accumulator, in fluid communication with the high pressure fuel pump, one or more injectors that are in fluid communication with the fuel accumulator and each of the fuel injectors. A main controller transmits a signal in response to a change in the throttle position. A fuel injection controller, in electrical communication with the main controller, in response to one or more signals relative to a transient operation, transmits one or more signals relative to fuel injection parameters of a fuel injection made during the transient operation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention is directed in general to an apparatus and method for decreasing the locomotive smoke emissions and engine noise when the operator advances the locomotive throttle position, and more specifically to an apparatus and method that adjusts the fuel injection pressure and/or number of injections made during a transient event or operation. 
         [0002]    Recent amendments to the United States environmental statutes and regulations require lowering of the permitted emissions from locomotive diesel engines, including visible smoke. One such requirement is the reduction in NO x  emissions, which can be effected by retarding the fuel injection timing of a locomotive diesel engine. But this timing modification negatively impacts fuel consumption and, therefore, it is desirable to increase the engine compression ratio to gain back some of the fuel composition losses. 
         [0003]    However, increasing the compression ratio also increases the visible smoke emissions at partial engine loading. The problem of visible smoke is especially acute during transient load and speed changes, i.e., when the locomotive operator advances the throttle (i.e., moves the throttle to a higher notch position) to call for higher speed and/or greater load pulling capacity (i.e., locomotive horsepower). A locomotive typically has 8 discrete notch settings called “notches”. 
         [0004]    Smoke emissions tend to be worse when the throttle is advanced to higher throttle positions when starting from lower positions. Excessive smoke during a transient has been addressed in the past with managing the rate that the load is applied, resulting in slower load application. Such a system and method are disclosed in U.S. Pat. No. 6,892,701. In addition, injection timing may be changed during a transient to help reduce smoke. Such as system and method is disclosed in U.S. Pat. No. 6,341,596. 
         [0005]    Currently, fuel systems on locomotives that incorporate unit pump systems are not capable of varying the fuel pressure. In this type of system, the injection event is dependant directly upon the amount of pressure in the high-pressure line. Therefore, the unit pump system has control only over the timing of the injection, or when the injection is made relative to the top dead center position of the piston. Moreover, the injection pressure cannot be varied for a fixed speed and horsepower of the locomotive. 
         [0006]    Other fuel systems such as the common rail fuel systems allow for more flexibility in developing fuel injection strategies. The injection event (or opening of the needle valve in the injector) is controlled by an electronic control unit (controller) and solenoid, and is not dependant on pressure in the high-pressure fuel lines leading to the injector. Such advanced fuel systems allow for fuel injection to take place at any time during the piston cycle and allow for multiple injections during a single cycle. In addition, the injection pressure is variable relative to the speed of the vehicle. A common rail fuel system for a locomotive engine is disclosed in a commonly United States published patent application, Pub. No. 20070012294. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0007]    In general, an embodiment of the present invention comprises a system for controlling locomotive smoke emissions and noise during transient operation wherein the locomotive comprises a throttle drivingly coupled to a diesel engine, and wherein an operator of the locomotive changes a throttle position as required during operation of the locomotive. The system may incorporate a high-pressure fuel system that can change fuel pressure, and/or the number of injections in an engine cycle, within the system independent of other injection parameters or variables. The locomotive has a locomotive controller for generating and sending a signal in response to a change in the throttle position, and one or more fuel pressure sensors for detecting a fuel pressure within the accumulator and sending the one or more signals relative such fuel pressure. In addition a fuel injection controller is in communication with the locomotive controller, the fuel pressure sensors, the one or more of the fuel injectors. The fuel injection controller in response to signals received from the locomotive controller and the fuel pressure sensors generates one or more signals relative to a fuel injection strategy during the transient operation and responsive to which a valve in the injector opens or closes and responsive to which a high pressure fuel pump increases or decreases the pressure level the fuel injection system. In addition, or alternatively, the fuel injection controller may transmit a signal indicative of a plurality of injections in a single engine cycle during the transient operation to reduce the noise emanating from the engine. 
         [0008]    In addition, an embodiment for the method allows for monitoring a parameter indicative of an increase in throttle notch setting from an idle setting to a powered notch setting. Data relative to the increase of the notch setting is transmitted to the fuel injector controller. The fuel injector performs a step of transmitting one or commands from the fuel injection controller relative to the pressure level at which fuel is injected into a cylinder during the transient operation from the first notch setting to the second notch setting. In addition, the locomotive may have a global positioning system that transmits data relative to geographical coordinates of the engine in order to identify a geographic area sensitive to noise or with reduced noise requirements, such as a passenger station. If the engine is so located, the fuel injector controller may transmit one or more commands indicative of a plurality of injections to be made in a single engine cycle during the transient operation i.e. when the engine throttle position is changed from idle to a first notch setting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings. 
           [0010]      FIG. 1  is a flow chart illustrating the operation of the invention. 
           [0011]      FIG. 2  is a block diagram and schematic of locomotive components associated with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Before describing in detail the particular transient smoke reduction system in accordance with the present invention, it should be observed that the present invention resides primarily in a novel combination of steps and apparatus related to smoke reduction in a railroad locomotive. Accordingly, these hardware components and method steps have been represented by conventional elements in the drawings, showing only those specific details that are pertinent to the present invention, so as not to obscure the disclosure with structural details that will be readily apparent to those skilled in the art having the benefit of the description herein. 
         [0013]    Though exemplary embodiments of the present invention are described with respect to rail vehicles, specifically locomotives having diesel engines, exemplary embodiments of the invention are also applicable for other uses, such as but not limited to off-highway vehicles, marine vessels, and stationary units, each which may use a diesel engine. Towards this end, when discussing a specified mission, this includes a task or requirement to be performed by the diesel powered system. Therefore, with respect to railway, marine or off-highway vehicle applications this may refer to the movement of the system from a present location to a destination. In the case of stationary applications, such as but not limited to a stationary power generating station or network of power generating stations, a specified mission may refer to an amount of wattage (e.g., MW/hr) or other parameter or requirement to be satisfied by the diesel powered system. Likewise, operating condition of the diesel-fueled power generating unit may include one or more of speed, load, fueling value, timing, etc. 
         [0014]    Exemplary embodiments of the invention solves the problems in the art by providing a system, method, and computer implemented method, such as a computer software code, for improving overall fuel efficiency and emissions through optimized power makeup. With respect to locomotives, exemplary embodiments of the present invention are also operable when the locomotive consist is in distributed power operations. 
         [0015]    Persons skilled in the art will recognize that an apparatus, such as a data processing system, including a CPU, memory, I/O, program storage, a connecting bus, and other appropriate components, could be programmed or otherwise designed to facilitate the practice of the method of the invention. Such a system would include appropriate program means for executing the method of the invention. 
         [0016]    Also, an article of manufacture, such as a pre-recorded disk or other similar computer program product, for use with a data processing system, could include a storage medium and program means recorded thereon for directing the data processing system to facilitate the practice of the method of the invention. Such apparatus and articles of manufacture also fall within the spirit and scope of the invention. 
         [0017]      FIG. 1  is a flow chart illustrating the operation of the present invention. At a step  10 , the locomotive operator&#39;s movement of the throttle handle toward a higher notch position is detected. A transient operational period (or transient event) ensues as the engine and locomotive operational parameters change to those commanded by the new notch position. Locomotives typically have a throttle system that includes eight discrete power settings or notches (N 1 -N 8  plus idle). Each notch represents a commanded engine speed and engine load, where N 1  may be a minimum engine speed and load and N 8  may be a maximum engine speed and load. In addition, the locomotive has a main controller that monitors and/or identifies each notch under which the locomotive engine is operating including the idle position. 
         [0018]    There are several engine and locomotive operational parameters that can be monitored to detect a notch increase, including, for example, engine speed (revolutions per minute), engine acceleration excitation current to the traction alternator, engine horsepower, engine fuel value (the quantity of fuel injected into an engine cylinder), traction motor alternator output current, vehicle speed, and manifold air pressure (which is influenced by the turbine speed and thus the engine speed). In response to one or more of these monitored parameters, at a step  12 , the locomotive controller (shown in  FIG. 1 ) determines that a notch change has occurred and sends a representative signal to a fuel injection system controller. The fuel injection controller controls the parameters or variables of a fuel injection. Such parameters may include the timing of an injection made during an injection event, the number of fuel injections made during an injection event, the duration of each fuel injection and the fuel injection pressure. 
         [0019]    In step  14  a sensor detects the fuel pressure within the fuel pump or a fuel accumulator (see  FIG. 2 ) of the fuel injection system for the diesel engine; and, with respect to step  16 , a signal indicative of the operating fuel pressure is sent to the fuel injection controller. 
         [0020]    While the embodiments described include a main controller and a fuel injection controller, a system and method may also integrate the function of the main controller and fuel injection controller into a single controller. 
         [0021]    Responsive to the signals received relative to the notch advance and the operating fuel pressure, the fuel injection controller determines what the fuel pressure should be at the detected notch setting in order to achieve a desired smoke emission. For example, at step  18  a look-up table stored in a database of the fuel injection may be consulted to determine the appropriate fuel pressure at the detected notch setting. One or more of the notch settings is associated with one or more predetermined fuel pressures or ranges of fuels pressures. At steps  22  and  24 , if the operating fuel pressure is not equal to, or does not fall within a given range of fuel pressures that are associated with the detected notch setting a signal is sent to the fuel pump (see  FIG. 2 ) to either decrease or increase the fuel pressure to fall within the selected range of fuel pressures. If operating fuel pressure is equal to a given fuel pressure, or does fall within a range of fuel pressures associated with the detected notch setting a signal is not sent. 
         [0022]    Upon detection of a transient event, an advanced fuel system such as a common rail fuel system as shown in  FIG. 2 , can increase fuel pressure at the fuel injection event. The increased injection pressure during a transient event promotes better air-fuel mixing in the cylinder, which results in more complete combustion and reduced smoke output. In contrast to prior art fuel injection systems for locomotives; the fuel injection pressure in the present system and method can be adjusted independent of other fuel injection parameters. 
         [0023]    Detection of a transient event such as the advance or increase in notch setting may also be utilized to reduce noise during the transient event. It is known that pilot injections may be used to reduce the noise associated with diesel engines, especially at idling speeds. A pilot injection introduces an amount of fuel prior to a main injection of fuel that smoothes the start of combustion eliminating the high pressure spikes that produce the high noise on diesel engines. The pilot injection results in a smoother combustion cycle and reduces the clatter or noise. 
         [0024]    At certain locations where a locomotive idles such as a passenger station, the noise level produced by the locomotive must fall within regulated guidelines. Accordingly, the fuel injection event may be adjusted to reduce noise levels when the locomotive is present at such a location. For example in step  10 , if the notch setting is advanced from an idle position to N 1 , the notch advance signal is sent in step  12  to the fuel injection controller. The signal is indicative of the notch advance from an idle setting to N 1 . The fuel injection controller is programmed to generate a signal indicative of a fuel injection strategy that includes a pilot injection or multiple fuel injections during a single engine cycle and the transient operation. 
         [0025]    In an embodiment, and with respect to step  26  in  FIG. 1 , the locomotive may have a global positioning system ( FIG. 2 ) that transmits to the fuel injection controller a signal including data relative to geographical coordinates of the engine. The fuel injection controller has a database that contains data including coordinates of one or more geographic area sensitive to noise or with reduced noise requirements, such as a passenger station. In steps  20  and  28 , responsive to a signal from the global positioning system, the fuel injection controller determines if the locomotive is located at a passenger station or a location that requires a fuel injection strategy to dampen engine noise. If the locomotive is located at a predetermined location such as a passenger station, in step  30 , the controller generates a signal representative of a fuel injection strategy that includes one or more pilot injections. In this manner, the fuel injection system and fuel injection strategy may control the noise output of the engine. 
         [0026]      FIG. 2  is a schematic illustration of a diesel engine  32  using diesel or alternate liquid fuels and incorporating a fuel injection control scheme providing enhanced engine performance in varying environmental conditions. Engine  32  is representative of any large, medium-speed, multi-cylinder diesel engine such as may be used in locomotive, marine or power generation applications. Engine  32  includes a plurality of power cylinders  34  (one illustrated) each having a piston  36  reciprocating therein. A fuel injection apparatus  38  injects fuel into the respective cylinders  34  in timed sequence with the reciprocation of the pistons  36 . The fuel injection apparatus  38  may be of the common rail fuel system type, or other advanced high pressure fuel system, and includes a fuel pump  40 , a fuel accumulator  42  that stores fuel under pressure and a fuel injector  44  associated with each cylinder  34 . Each fuel injector  44  preferably includes a valve that opens or closes responsive to commands from a fuel injection controller  46  and/or a solenoid (not shown). A pressure sensor  48  transmits a signal  50  to the fuel injection controller  46 , which signal is indicative of a fuel pressure in the accumulator  42  and/or the fuel pump  40 . 
         [0027]    The engine  32  also includes an engine power and/or throttle position selection and sensing apparatus, collectively referred to herein as throttle  52 . The throttle  52  provides a power demand signal  54  that is responsive to an operator throttle input. For locomotive engines, the throttle input will typically include a plurality of discrete throttle settings that are commonly referred to as notches, such as N 1  thru N 8 , and an idle setting. The demand signal  54  may be sent to a locomotive controller  56  or directly to the fuel injection controller  46  as represented by the dashed line. 
         [0028]    Responsive to the signal  54  from the locomotive controller  56  or the throttle  52 , the fuel injection controller  46  identifies the transient event or the advance from an idle setting to a powered notch setting. In addition, responsive the signal  50  relative to the fuel pressure, the fuel injection controller  46  determines if the fuel pressure falls within predetermined acceptable limits. The fuel injector controller  46  transmits a command signal  62  indicative of a change in fuel pressure and in response to transition in notch settings  54  and the fuel pressure signal  50 . 
         [0029]    The fuel injection controller  46  also transmits one or command signals  64  to the fuel injector which signal  64  comprises data relative to injection parameters such as fuel injection timing, the number of injections made during an engine cycle and/or the duration. In an embodiment of the invention, a global positioning system  58  transmits a signal  60  to the fuel injection controller  46 , which signal  60  includes coordinates of a geographical location of the engine  32 . The fuel injection controller  46  may be programmed with a memory or database that includes data relative to one or more geographic locations sensitive to noise or with reduced noise requirements, such as a passenger station. In addition, the database or memory may include predetermined fuel injection parameters associated with the geographic locations. The fuel injection controller  46  transmits a command signal  64  indicative of a fuel injection strategy to reduce noise emanating from the engine  32 . More specifically, the injection strategy may include multiple injections during an engine cycle, or pilot injections. In this manner, the fuel injection controller  46 , and or global positioning system  58  may more precisely identify when pilot injections may be used to reduce the noise level of the engine  32 . 
         [0030]    In addition, the embodiment in which detection of a transient event such as changing the notch settings may prompt increasing or decreasing fuel pressure may be incorporated with identifying the location of the engine  32 . By way of example, if an engine  32  is located at a passenger station and is idling an operator may adjust the throttle  52  to a powered notch. Responsive to the control signal  54  and the location signal  60 , the fuel injection controller  46  generates a signal  62  to increase fuel injection pressure and inject multiple times (pilot injections) during an engine cycle. 
         [0031]    While the preferred embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those of skill in the art without departing from the invention herein. Therefore, it is intended that the invention not be limited to the particular disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.