Patent Application
20100095935
In accordance with exemplary embodiments, the present invention relates to systems and methods for pressurization of a fuel line of an internal combustion engine, particularly prior to or simultaneously with initial ignition or cranking of the engine.
Engines require positive fuel pressure within the fuel line for achieving startup. For certain engines, particularly hybrid engines utilizing ethanol fuel such as E85 Flex Fuel vehicles or otherwise, it is important that sufficient fuel pressure be established relatively quickly; otherwise, the engine may have difficulty starting and/or generate poor exhaust emissions. Also, during cold starts of the engine, or under cold operating conditions, immediate fuel pressure to the engine improves startability of the engine and reduces emissions, such as unburned hydrocarbons. However, to date there have been few designs that provide for rapid pressurization of a fuel line, particularly for ethanol burning engines or for cold starts situations, that are simple in design and relatively cost effective. Accordingly, there exists a need for an improved system and method for providing rapid pressurization of a fuel line of an engine.
In accordance with exemplary embodiments, the present invention relates to systems and methods for pressurization of a fuel line of an internal combustion engine, particularly prior to or simultaneously with an initial ignition or cranking of the engine. In one particular exemplary embodiment, a fuel charging system for an internal combustion engine is provided. The fuel charging system includes a first fuel pump in fluid communication with a fuel tank. The first fuel pump generates a first fluid pressure within a first fuel line. The fuel charging system also includes a second fluid pump having a reciprocating piston including a low pressure end and a high pressure end. The low pressure end is in fluid communication with the first fuel pump through the first fuel line and the high pressure end is in fluid communication with an engine fuel rail through a second fuel line. The reciprocating piston is driven by the first fluid pressure to generate a second fluid pressure within the second fuel line, wherein the second fluid pressure is greater than the first fluid pressure.
In another particular exemplary embodiment, a method of charging an engine fuel rail of an engine is provided. The method includes: fluidly coupling a first fluid pump to a fuel tank; fluidly coupling a second fluid pump to the first fluid pump and the engine fuel rail, the second fluid pump including a reciprocating piston having a low pressure end and a high pressure end; generating a first fluid pressure with the first fluid pump, the first fluid pressure acting on the low pressure end of the second fluid pump; and generating a second fluid pressure with the high pressure end of the second fluid pump proportional to the first fluid pressure, the second fluid pressure being greater than the first fluid pressure.
The above-described and other features and advantages of the exemplary embodiments of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.
Other objects, features, advantages and details of the exemplary embodiments appear, by way of example only, in the following detailed description of the exemplary embodiments, the detailed description referring to the drawings in which:
Exemplary embodiments of the present invention provide for distribution of fuel to a fuel system of an engine. More so, exemplary embodiments provide for rapid pressurization of fuel lines used to supply components of the engine, such as fuel rails or otherwise, through the use of a hydraulic multiplier used to passively prime the fuel rail. This is particularly advantageous for engines requiring rapid fuel pressurization or fuel pressurization prior to starting or cranking of the engine, such as engines using ethanol or other less volatile burning agents, or engines operating in cold climates. This also provides for reduced emissions during start-up of the engine, such as reduced hydrocarbons or otherwise. In one configuration, the fuel charging system includes a pump configured to cause pressurization of a fuel rail prior to or simultaneously with initial rotation of the engine, such as is typically done by an engine starter. Advantageously, this fuel pressurization reduces or eliminates fuel vapors and collapses air within the fuel system into the fuel solution to create a single mixture. Such pressurization may be initiated by a user through a remote device, such as a radio frequency identification device (RFID), remote unlocking device, or otherwise. Such pressurization may also be initiated by a user proximate to the vehicle, such as during unlocking or opening of a vehicle door, placement or rotation of a key in an ignition or otherwise. Accordingly, no longer is the fuel system dependent upon mechanical rotation of a fuel pump for causing pressurization of a fuel line during the initial start of the engine.
In one configuration, the fuel charging system includes an amplification pump configured to amplify fuel pressure for a fuel rail of an engine. The amplification pump is powered by fluid pressure formed by a low pressure pump associated with a fuel tank. The low pressure pump also provides a source of fuel for the amplification pump. In one particular configuration, the amplification pump includes a moveable member, such as a piston, having a first surface area in fluid communication with the low pressure pump and a second surface area in fluid communication with the fuel rail, wherein the first area is greater than the second surface area. This surface area ratio provides the ability to concentrate the force generated by the low pressure pump to a smaller surface area thus increasing the fluid pressure to the fuel rail, e.g., pounds per square inch (PSI) or Pascals. Once the engine begins operation, a mechanically driven pump continues to provide suitable fuel pressurization for the fuel rail.
For example, referring to the exemplary embodiments shown in
More particularly, in the exemplary embodiment shown in
In the exemplary embodiment shown in
In greater detail, the amplifier pump 16 may comprise any suitable passive pump for providing a supply of high pressure fuel as a result of fluid pressure generated by the low pressure pump 18. With reference to the exemplary embodiments shown in
In one exemplary embodiment, with respect to the piston pump 36, the first surface area 28 and second surface area 30 may vary depending on the desired output pressure, e.g., second fluid pressure or otherwise. It is contemplated that a surface area ratio is formed between the first surface area 28 and the second surface area 30. This surface area is directly correlated to a pressure ratio between the first pressure and the second pressure. In one configuration, the area ratio is between about 2:1 to about 10:1 with respect to the first and second surface area. In another configuration the second surface area is at least about twice as large as the first surface area. In one particular configuration, the area ratio is about 7:1.
With respect to first and second surface area ratios, certain pressures can be expected, for the high pressure, through the cyclical action of the pump. Such cyclical action will continue until pressure equalization is achieved, e.g., the pressure generated by the piston pump 36 is equal to the pressure within the fuel rail 12. For example, in one configuration, upon cyclical action of the pump, the maximum pressure generated within the pump may be as much as about 2 MPa. However, other pressures are contemplated which may be based upon the desired rate for pressurizing of the fluid rail 12.
Piston 38 includes fluid passage 54 for providing fluid communication between the high pressure cavity 52 and low pressure pump 18. The piston 38 further includes a first check valve 56 for preventing fluid flow through the fluid passage during generation of the second fluid pressure. This configuration provides fluid flow through fluid passage 54 during movement of the piston 38 towards the first side 46 of the piston housing 40 but prevents fluid flow through the fluid passage during movement of the piston towards the second side 48 of the piston housing. The prevention of fluid flow through the fluid passage 54 during movement of the piston towards the second end of the piston housing provides for incremental pressure build up of the second fluid pressure within the fuel rail 12. Accordingly, repetitious movement of the piston 38 between the first and second end 46, 48 of the piston housing 40 progressively increases the second fluid pressure within the fuel rail through incremental pressure buildup. The build up of pressure is further achieved through a second check valve 58 configured for maintaining the incremental pressure build up within the fuel rail 12. This movement is continuous until the incremental pressure generated by piston 38 is equal to that of the second fluid pressure, e.g., pressure built up within the fuel rail 12.
Piston pump 36 is further configured for movement of the piston 38 during a non-compressive stroke, e.g., movement of the piston from the second end 48 of the piston housing 40 towards a first end 46 of the piston housing. In one exemplary embodiment, referring to
Referring again to the first and second check valves 56, 58, the establishment and prevention of fluid flow into and out of the high pressure cavity 52 may be established in a number of different ways. For example, with reference to
With respect to an operational sequence of the amplification pump shown in
Once the piston 38 has been fully deployed towards the second end of the piston housing and pressure from the low pressure pump is actively removed or depleted, a spring force (e.g., return spring 60) returns the piston to its original position towards the first end 46 of the piston housing 40. During this return motion, first ball 66 (or first cylindrical valve member 74) unseats allowing fluid to flow through fluid passage 54 to fill high pressure cavity 52, at the low pressure rate. Also, the fuel pressure built up within the fuel rail 12, or connection thereto, i.e., pressure line 26, causes second ball 68 (or second cylindrical valve member 76) to be seated against second seat 72 (or second seat 80) thereby preventing fluid flow back into high pressure cavity 52. Once the piston has returned to an original position, then the low pressure pump 18 is used to actively generate fluid pressure thereby repeating the process until the second fuel pressure within the fuel rail, or fluid connector thereto, i.e., pressure line 26, is equal to the pressure generated by the second surface area 30. Accordingly, the amplification pump 16 becomes a reciprocating pump powered by intermittent activation of the low pressure pump.
It should be appreciated that other amplification pumps 16 are available which provide increased fluid pressure based upon a lower fluid pressure. It is further contemplated that the amplification pump may comprise any means of converting mechanical force to hydraulic pressure including vanes, gears, pistons or otherwise. Still further, a hydraulic motor may be used to drive a smaller pump. Other configurations are contemplated.
In one exemplary embodiment, one or more components of the fuel charging system 10, are controlled through a controller 84. The controller may be in power communication, signal communication, or both, to one or more components through an electrical conduit, such as a wire 86. For example, the controller 84 may be configured for providing power and/or controlling operation (e.g., speed or otherwise) of the low pressure pump and thus the amplification pump 16. The controller 84 may also be configured for synchronizing operation of the low pressure pump 18 and amplification pump 16. Thus, the controller may include instructions and/or algorithm for activating (intermittent or otherwise) the low pressure pump and the thus the passive amplification pump. These instructions may be configured to generate a specific pressure within the fuel rail through a pre-set number of cyclical movements of the piston 38 of the piston pump 36. The controller 84 may comprise a stand alone component or may comprise a portion of a more encompassing controller, such as an engine control unit of a vehicle.
Referring again to the fuel charging system shown in
It should be appreciated that the fuel charging system may be used with different types of engines and in different engine applications. For example, the fuel charging system 10 may be used in gasoline engines, diesel engines, hybrid engines such as ethanol or alcohol burning engines or otherwise. Also, the fuel charging system 10 may be used in stationary engines, such as power generators, pumps or otherwise. The fuel charging system 10 may be used in non-stationary engines such as vehicle engines. Other applications are possible.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment 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.
