| System for selective homogeneous charge compression ignition -> Monitor Keywords |
|
|
  System for selective homogeneous charge compression ignitionUSPTO Application #: 20070175205Title: System for selective homogeneous charge compression ignition Abstract: A method of operating an internal combustion engine may include selectively operating the engine in a first mode of operation, wherein fuel may be injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel may be ignited by the heat of the compressed fluid. The method may also include selectively operating the engine in a second mode of operation, wherein fuel is injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture is compressed, and fuel is ignited by the heat of the compressed gas. The method may further include determining whether to operate the engine in the first or second mode according to engine conditions. (end of abstract)
Agent: Caterpillar/finnegan, Henderson, L.L.P. - Washington, DC, US Inventors: Wade J. Robel, James J. Driscoll, William L. Easley USPTO Applicaton #: 20070175205 - Class: 060286000 (USPTO) Related Patent Categories: Power Plants, Internal Combustion Engine With Treatment Or Handling Of Exhaust Gas, By Means Producing A Chemical Reaction Of A Component Of The Exhaust Gas, Condition Responsive Control Of Heater, Cooler, Igniter, Or Fuel Supply Of Reactor The Patent Description & Claims data below is from USPTO Patent Application 20070175205. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD [0001] The present disclosure relates generally to internal combustion engines, and more particularly to the operation of a diesel engine in a homogeneous charge compression ignition mode. BACKGROUND [0002] A diesel engine may typically include a combustion chamber composed of a piston slidably mounted within a cylinder. The conventional combustion process in the diesel engine may be initiated by the direct injection of fuel into the cylinder after upward movement of the piston has created a volume of highly compressed air within the top portion of the cylinder. The fuel may be almost instantaneously ignited upon being injected into the highly compressed air, and thus may produce a diffusion flame or flame front extending along the plumes of the injected fuel. The production of the diffusion flame or flame front may result in the presence of pollutants in the diesel engine's exhaust stream. These pollutants may include, for example, particulate matter, nitrogen oxides ("NOx"), and sulfur compounds. [0003] Due to heightened environmental concerns, engine exhaust emission standards have become increasingly stringent. The amount of pollutants in the exhaust stream emitted from the diesel engine may be regulated depending on the type, size, and/or class of engine. One method implemented by engine manufacturers to comply with the regulation of exhaust stream pollutants has been to employ a selective catalytic reduction ("SCR") catalyst to clean NOx from the engine exhaust stream. Use of the SCR catalyst is disclosed in U.S. Pat. No. 6,823,660 to Minami. Minami also discloses that although the SCR catalyst has a high rate of clean-up (NOx reduction) at higher exhaust stream temperatures, the SCR catalyst's ability to clean drastically declines in idling or low engine load conditions, where the temperature of the exhaust stream falls. One reason for the decline is that the rate of NOx conversion is strongly affected by the temperature of the exhaust stream. Minami proposes raising the temperature of the exhaust stream before it passes through the SCR catalyst to provide near 100% removal of NOx. However, increasing the temperature of the exhaust stream in the manner proposed by Minami requires a rather complex arrangement of valve devices and conduits, and further, may require the use of extra fuel and/or energy. [0004] On the other hand, allowing the exhaust stream to remain at lower temperatures may result in the presence of a greater amount of pollutants in the exhaust stream. As newer engines may also include a diesel particulate filter ("DPF") to catch pollutants, allowing those pollutants to reach the DPF may cause clogging and may decrease the DPF's performance. Thus, the DPF may require frequent maintenance and/or regeneration to perform satisfactorily. [0005] The system of the present disclosure is directed towards overcoming one or more of the constraints set forth above. SUMMARY OF THE INVENTION [0006] In one aspect, the present disclosure may be directed to a method of operating an internal combustion engine. The method may include selectively operating the engine in a first mode of operation, wherein fuel may be injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel may be ignited by the heat of the compressed fluid. The method may also include selectively operating the engine in a second mode of operation, wherein fuel may be injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture may be compressed, and fuel may be ignited by the heat of the compressed gas. The method may further include determining whether to operate the engine in the first or second mode according to engine conditions. [0007] In another aspect, the present disclosure may be directed to an internal combustion engine. The internal combustion engine may include a combustion chamber including a piston and a cylinder, and a fuel injection controller that selectively operates the engine in first and second modes of operation, and selects the mode according to engine conditions. In the first mode, fuel may be injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel may be ignited by the heat of the compressed fluid. In the second mode, fuel may be injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture may be compressed, and fuel may be ignited by the heat of the compressed gas. [0008] In yet another aspect, the present disclosure may be directed to a work machine having an internal combustion engine. The internal combustion engine may include a combustion chamber including a piston and a cylinder, and a fuel injection controller that may selectively operate the engine in first and second modes of operation, and may select the mode according to engine conditions. In the first mode, fuel may be injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel may be ignited by the heat of the compressed fluid. In the second mode, fuel may be injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture may be compressed, and fuel may be ignited by the heat of the compressed gas. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 provides a diagrammatic view of a combustion chamber according to an exemplary disclosed embodiment. [0010] FIG. 2 provides a closer view of the combustion chamber of FIG. 1. [0011] FIG. 3 provides another view of the combustion chamber of FIG. 1. [0012] FIG. 4 provides a flow diagram of a method, according to an exemplary disclosed embodiment. DETAILED DESCRIPTION [0013] Reference will now be made in detail to the drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. [0014] FIG. 1 illustrates a combustion chamber 10 of an internal combustion engine 12. Although only a single combustion chamber 10 is shown, it should be understood that engine 12 may include multiple combustion chambers. Combustion chamber 10 may be formed by a cylinder sidewall 14, a cylinder end wall 16, and a reciprocating piston 18, and may include a combustion chamber longitudinal axis 20. [0015] Reciprocating piston 18 may include a sliding plug 22 that may fit closely inside a bore defined by cylinder sidewall 14. Plug 22 may include a top surface 24 and a bottom surface 28 operatively connected to a crankshaft 30 by a connecting rod 32. Piston 18 may reciprocate within the bore by sliding back and forth between two positions while performing combustion cycles. The first position may be referred to as a top dead center position ("TDC") corresponding to the position where plug 22 may be furthest from crankshaft 30. The second position may be referred to as a bottom dead center position ("BDC") corresponding to the position where plug 22 may be closest to crankshaft 30. Accordingly, TDC and BDC may define the upper and lower extents of piston travel, respectively. Additionally or alternatively, the movement of piston 18 may be described according to the angular rotation of crankshaft 30 caused by movement of piston 18. For example, movement of piston from BDC to TDC may cause crankshaft 30 to rotate 180 degrees or one-half revolution. Thus, as piston 18 travels from BDC to TDC, it may be characterized as having traveled 180 degrees. The reciprocating movement of piston 18 between TDC and BDC may deliver power to crankshaft by ways known to those skilled in the art. [0016] An intake port 34, intake valve 36, exhaust port 38, and exhaust valve 40 may be located about the cylinder end wall 16, as shown in FIG. 2. Intake valve 36 may be disposed in intake port 34 and may be operable to fluidly connect air intake port 34 with combustion chamber 10. Exhaust valve 40 may be fluidly coupled with combustion chamber 10 and may be operable to couple combustion chamber 10 with exhaust port 38. Intake port 34, intake valve 36, exhaust port 38, and exhaust valve 40 may function in ways known to those skilled in the art. Additionally or alternatively, intake port 34 and/or combustion chamber 10 may be configured to induce a swirl to fluids and/or gases in combustion chamber 10. [0017] A fuel injector 42 may include a nozzle tip 44 extending directly into combustion chamber 10 through an opening 46 in cylinder end wall 16. As shown in FIG. 3, nozzle 44 may be configured to inject fuel such that fuel plumes 70 may be formed above a piston crater 26 in top surface 24 of plug 22. Fuel injector 42 may be concentric or parallel with the longitudinal axis 20 of combustion chamber 10, or may extend at an acute angle with respect to longitudinal axis 20 of combustion chamber 10. Further, fuel injector 42 may be of any conventional type. For example, fuel injector 42 may be of the mechanically actuated, hydraulically actuated, or common rail type, and may be designed for single mode or mixed mode operations. If intake port 34 and/or combustion chamber 10 is configured to induce a swirl, as discussed above, fuel injected by fuel injector 42 may be less likely to stick to cylinder sidewall 14. [0018] In operation, fuel injector 42 may provide a combustible fuel to combustion chamber 10 as a function of a control signal. For example, during normal to high load engine operation, fuel injector 42 may receive a control signal causing fuel injector 42 to inject fuel into combustion chamber 10 one or more times. For example, fuel injector 42 may inject a first amount of fuel (a pilot injection) when piston 18 is located at any position between BDC and approximately 40 degrees before TDC. The pilot injection may mix with the intake air within combustion chamber 10, and the mixture may be compressed as piston 18 travels towards TDC position. The pilot injection/intake air mixture may combust when its combustion temperature is reached, such as, for example, when the heat of the compressed intake air is sufficient to ignite the pilot injection. Fuel injector 42 may also inject a second amount of fuel (a main injection) into the combustion chamber 10 contemporaneous with or slightly before the combustion temperature of the pilot injection/intake air mixture is reached in combustion chamber 10. The main injection may combust upon being introduced into the pilot injection/intake air mixture, due at least in part to its exposure to the heat associated with the pilot injection/intake air mixture. This may be referred to as a first mode of operation for engine 12. Additionally or alternatively, in the first mode, the pilot injection may be omitted. In such an embodiment, the intake air may be compressed by piston 18 as it travels towards TDC position. The main injection may be injected into the compressed intake air. If the compressed intake air has reached the combustion temperature, then the main injection may ignite immediately upon being introduced into combustion chamber 10 due to the heat of the compressed intake air. Additionally or alternatively, the main injection may ignite shortly after being injected into combustion chamber 10. [0019] During idling or low load engine operation, the control signal may be altered such that fuel injector 42 may inject fuel into combustion chamber 10 only when piston 18 may be closer to BDC. This may be achieved by, for example, modifying the pilot injection from the first mode, and eliminating the main injection from the first mode. This may be referred to as a second mode of operation for engine 12. The designation of "first" and "second" modes are for explanation purposes only and have no other significance. Moreover, the terms "low load", "normal load", and "high load", may be relative. For example, idle or low load condition for an engine lacking an exhaust gas recirculation ("EGR") assembly (not shown) may begin at or around 25% load (approximately 600 kPaBMEP), whereas for an engine having an EGR assembly, idle or low load condition may begin at or around 50% load (approximately 1200 kPaBMEP). Thus, it should be understood that the meaning of low, normal, and high load will vary by engine, and these designations are not intended to be limiting to the overall disclosed concept. Continue reading... Full patent description for System for selective homogeneous charge compression ignition Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this System for selective homogeneous charge compression ignition patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like System for selective homogeneous charge compression ignition or other areas of interest. ### Previous Patent Application: Scr muffler Next Patent Application: Hydraulic system having in-sump energy recovery device Industry Class: Power plants ### FreshPatents.com Support Thank you for viewing the System for selective homogeneous charge compression ignition patent info. IP-related news and info Results in 2.95297 seconds Other interesting Feshpatents.com categories: Tyco , Unilever , Warner-lambert , 3m |
||
