| System and method for controlling engine operation -> Monitor Keywords |
|
|
 
System and method for controlling engine operationRelated Patent Categories: Internal-combustion Engines, Poppet Valve Operating Mechanism, Hydraulic SystemSystem and method for controlling engine operation description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060011159, System and method for controlling engine operation. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD [0001] The present invention is directed to a system and method for controlling the operation of an engine. More particularly, the present invention is directed to a system and method for controlling the actuation timing of engine valves. BACKGROUND [0002] The operation of an internal combustion engine, such as, for example, a diesel, gasoline, or natural gas engine, may cause the generation of undesirable emissions. These emissions, which may include particulates and oxides of nitrogen (NOx), are generated when fuel is combusted in a combustion chamber of the engine. An exhaust stroke of an engine piston forces exhaust gas, which may include these emissions from the engine. If no emission reduction measures are in place, these undesirable emissions will eventually be exhausted to the environment. [0003] Research is currently being directed towards decreasing the amount of undesirable emissions that are exhausted to the environment during the operation of an engine. It is expected that improved engine design and improved control over engine operation may lead to a reduction in the generation of undesirable emissions. Many different approaches, such as, for example, exhaust gas recirculation, water injection, fuel injection timing, and fuel formulations, have been found to reduce the amount of emissions generated during the operation of an engine. Aftertreatments, such as, for example, traps and catalysts have been found to effectively remove emissions from an exhaust flow. Unfortunately, the implementation of these emission reduction approaches typically results in a decrease in the overall efficiency of the engine. [0004] Additional efforts are being focused on improving engine efficiency to compensate for the efficiency loss due to the emission reduction systems. One such approach to improving the engine efficiency involves adjusting the actuation timing of the engine valves. For example, the actuation timing of the intake and exhaust valves may be modified to implement a variation on the typical diesel or Otto cycle known as the Miller cycle. In a "late intake" type Miller cycle, the intake valves of the engine are held open during a portion of the compression stroke of the piston. [0005] The engine valves in an internal combustion engine are typically driven by a cam arrangement that is operatively connected to the crankshaft of the engine. The rotation of the crankshaft results in a corresponding rotation of a cam that drives one or more cam followers. The movement of the cam followers results in the actuation of the engine valves. The shape of the cam governs the timing and duration of the valve actuation. As described in U.S. Pat. No. 6,237,551 to Macor et al., issued on May 29, 2001, a "late intake" Miller cycle may be implemented in such a cam arrangement by modifying the shape of the cam to overlap the actuation of the intake valve with the start of the compression stroke of the piston. [0006] However, while valve actuation timing adjustments may provide efficiency benefits, these actuation timing adjustments may also result in detrimental engine performance under certain operating conditions. For example, a late intake Miller cycle may be inefficient when the engine is starting, operating under cold conditions, or experiencing a transient condition, such as a sudden increase in engine load. This detrimental engine performance is caused by a decrease in the mass of air flowing through the engine. Especially under cold ambient conditions, the delayed start of compression may lead to insufficient cylinder temperatures to support good combustions and startability. [0007] As noted above, the actuation timing of a valve system driven by a cam arrangement is determined by the shape of the driving cam. Because the shape of the cam is fixed, this type of arrangement is inflexible and may only be changed during the operation of the engine through the use of complex mechanical mechanisms. [0008] The engine operation control system and method of the present invention solves one or more of the problems set forth above. SUMMARY OF THE INVENTION [0009] In one aspect, the present invention is directed to a method of operating an engine that has a cylinder, an intake valve associated with the cylinder and moveable between a first position where the intake valve prevents a flow of fluid to the cylinder and a second position where the intake valve allows a flow of fluid to the cylinder, a cam assembly connected to the intake valve to move the intake valve between the first and second positions, and an actuator connected to the intake valve. At least one operating parameter of the engine is sensed. The engine is operated in a first mode in response to the sensed operating parameter being at one of a predetermined first set of conditions. In the first mode, the cam assembly begins to move the intake valve from the first position toward the second position when the piston is at or near a top dead center position of an intake stroke and the cam assembly returns the intake valve to the first position when the piston is at or near a bottom dead center position of the intake stroke. The engine is operated in a second mode in response to the sensed operating parameter being at one of a predetermined second set of conditions. In the second mode, the cam assembly begins to move the intake valve from the first position toward the second position when the piston is at or near a top dead center position of an intake stroke and the actuator prevents the intake valve from returning to the first position in response to the cam assembly. [0010] In another aspect, the present invention is directed to an engine that includes an engine block defining a cylinder. A piston is slidably disposed within the cylinder and is moveable between a top dead center position and a bottom dead center position. An intake valve is operatively associated with the cylinder and is moveable between a first position where the intake valve prevents fluid from flowing to the cylinder and a second position where a flow of fluid is allowed to enter the cylinder. A cam assembly is connected to the intake valve to move the intake valve between the first and second positions. An actuator is configured to selectively prevent the intake valve from returning to the first position. A sensor is configured to sense at least one operating parameter of the engine. A controller is operable to selectively operate the engine in a first mode or a second mode based on the sensed operating parameter. In the first mode, the cam assembly begins to move the intake valve from the first position toward the second position when the piston is at or near the top dead center position of an intake stroke and the cam assembly returns the intake valve to the first position when the piston is at or near a bottom dead center position of the intake stroke. In the second mode, the cam assembly begins to move the intake valve from the first position toward the second position when the piston is at or near the top dead center position of an intake stroke and the actuator prevents the intake valve from returning to the first position in response to the cam assembly. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 is a diagrammatic cross-sectional view of an exemplary embodiment of an internal combustion engine; [0012] FIG. 2 is a diagrammatic cross-sectional view of a cylinder and valve actuation assembly in accordance with an exemplary embodiment of the present invention; [0013] FIG. 3 is a schematic and diagrammatic representation of a fluid supply system for a fluid actuator for an engine valve in accordance with an exemplary embodiment of the present invention; [0014] FIG. 4a is a schematic and diagrammatic representation of a fluid supply system for a fluid actuator in accordance with another exemplary embodiment of the present invention; [0015] FIG. 4b is a schematic and diagrammatic representation of a fluid supply system for a fluid actuator in accordance with another exemplary embodiment of the present invention; [0016] FIG. 5 is a graphic illustration of an exemplary intake valve actuation as a function of engine crank angle in accordance with the present invention; and [0017] FIG. 6 is a flowchart illustrating an exemplary method of controlling the operation of an engine in accordance with the present invention. DETAILED DESCRIPTION [0018] An exemplary embodiment of an internal combustion engine 20 is illustrated in FIG. 1. For the purposes of the present disclosure, engine 20 is depicted and described as a four stroke diesel engine. One skilled in the art will recognize, however, that engine 20 may be any other type of internal combustion engine, such as, for example, a gasoline or natural gas engine. [0019] As illustrated in FIG. 1, engine 20 includes an engine block 28 that defines a plurality of cylinders 22. A piston 24 is slidably disposed within each cylinder 22. In the illustrated embodiment, engine 20 includes six cylinders 22 and six associated pistons 24. One skilled in the art will readily recognize that engine 20 may include a greater or lesser number of pistons 24 and that pistons 24 may be disposed in an "in-line" configuration, a "V" configuration, or any other conventional configuration. Continue reading about System and method for controlling engine operation... Full patent description for System and method for controlling engine operation Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this System and method for controlling engine operation 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 and method for controlling engine operation or other areas of interest. ### Previous Patent Application: System for controlling electromechanical valves in an engine Next Patent Application: Valve case and resin cylinder head cover Industry Class: Internal-combustion engines ### FreshPatents.com Support Thank you for viewing the System and method for controlling engine operation patent info. IP-related news and info Results in 0.27251 seconds Other interesting Feshpatents.com categories: Canon USA , Celera Genomics , Cephalon, Inc. , Cingular Wireless , Clorox , Colgate-Palmolive , Corning , Cymer , 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
