Internal-combustion engines – Charge forming device – Fuel flow regulation between the pump and the charge-forming...
Reexamination Certificate
2001-06-18
2004-05-04
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel flow regulation between the pump and the charge-forming...
C123S557000, C123S541000
Reexamination Certificate
active
06729310
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to methods and apparatus in the field of fuel supply systems for internal combustion engines and, more specifically, to systems having components that cooperate to remove contaminants, such as entrained air, from an incoming fuel supply such as diesel fuel.
2. Statement of the Problem
Typical fuel supply systems for diesel engines operate on the principle of a vacuum feed system in which fuel resides within a fuel tank that feeds fuel through a fuel line to a transfer pump or a fuel pump. A fuel filter is most often positioned in the fuel line to remove particles and water from the incoming fuel supply. The fuel line feeds the fuel to an inlet of the transfer pump or fuel pump, which operates to pressurize the fuel for delivery to a fuel injector. Various mechanical and electromechanical linkages exist for fuel delivery, such as distributor-type pumps or electronic control module (ECM) systems that deliver fuel from a common rail system.
Operational deficiencies and inefficiencies of the diesel engine are well known, but commercial implementations of such engines have failed to address known problems. Diesel engines lose power, develop increased exhaust smoke, increased fuel consumption and throttle response symptoms as the fuel filter plugs with use. High-speed diesel engines for use in automotive and marine applications lose torque at higher revolutions. Engine power output is derated for operation at higher altitudes. The industry has simply accepted the fact that such engines operate better on some days than others, and has not sufficiently investigated or corrected the problem, which may be observed by visible changes in the exhaust from a given engine at different times.
The aforementioned problems are commonly perceived to involve timing changes, and the industry has addressed these by the development of “ECM” technology. Diesel fuel injection systems are primarily hydraulic systems, whether they are mechanically timed or electronically controlled. The injector timing must be precise to a millisecond or engine efficiency suffers. According to the principles of operation for diesel engines, the injectors are timed to deliver fuel to a compressed air body that resides within a piston-cylinder assembly as the piston rises towards top dead center (TDC), i.e., the top of the stroke. The heat created by pressure is sufficient to cause ignition of the fuel as it combines with oxygen in the air. The injector pulse ideally delivers a spray of fuel at an instantaneous point in time, but the reality is that the spray persists for only an instant, e.g., about five milliseconds or less at idle. Thus, engine performance is optimized for initialization of the injector timing at a point in time prior to when the piston reaches TDC. Combustion byproducts, such as nitrous oxide and particulates, are reduced by this optimization. Additional features of optimized engine performance include an optimized conical spray pattern geometry and a spray of minimum duration. Entrained air on the pressurized side of the diesel injector pump disrupts the spray pattern, retards the injection timing, and on ‘ECM’ controlled engines, increases the duration of the injection, all of which reduces the available power from the engine and result in incomplete fuel combustion.
U.S. Pat. Nos. 5,746,184 and 5,355,860 to Ekstam both address fuel delivery systems for diesel engines, and are hereby incorporated by reference to the same extent as though fully disclosed herein. These patents provide a significant advance in the art by demonstrating that diesel engine performance can be enhanced through the use of an air-fuel separation system that removes entrained air from the fuel. These systems are now sold commercially under the trademark FUEL PREPARATOR® as retrofit devices for diesel engines and consistently provide significant improvements to fuel economy together with reduced particulate matter, carbon monoxide, and NOX emissions. According to U.S. Pat. No. 5,746,184, fuel is fed to the filter under a positive pressure where the filter has pore openings sized smaller than 25 microns and, preferably, of about 15 microns.
The vacuum feed concept of fuel pump intake systems has lead to commercial implementations of fuel transfer and injector pumps having vacuum and cavitation problems that add vapor phases of air and flashed fuel vapor to the fuel. It has been documented that the air which is usually dissolved in a fuel is pulled out of solution at the inlet side of these pumps due to suction at the intake. A greater vacuum pressure or suction is associated with increased chances of cavitation that further increases the amount of vapor that is entrained in the fuel. U.S. Pat. No. 5,539,214 to Ekstam, which is hereby incorporated by reference to the same extent as though fully disclosed herein, teaches the use of a fuel-fed double seal assembly providing improved isolation of intake and outlet sides of a fuel pump.
Various regulatory agencies including federal, state and municipal governments are studying the environmental problems associated with diesel emissions. The primary problems are that diesels emit a relatively disproportionate share of NOX and particulate emissions, which result in an unsightly brown cloud. The particulates are increasingly suspected or implicated as a cause of respiratory problems. Various regulatory schemes have been proposed or implemented to address these problems. There is a real and growing danger that diesel engines, as they are presently constructed, will be unable to meet future emissions requirements without substantial changes to diesel fuels and the use of particulate traps. Although the currently manufactured and commercially marketed model of U.S. Pat. Nos. 5,355,860 and 5,746,184, work well, filter design and size relationship to the device could cause models with greater volume and flow capacity to become quite large and bulky.
SOLUTION
The present invention overcomes the problems that are outlined above by providing further enhancements to fuel delivery systems and methods. In combination and as individual components, these enhancements result in improved fuel economy and reduced emissions across a wide variety of diesel engine applications.
One aspect of the fuel delivery system described herein is to provide improvements to prior air-fuel separation systems.
For example, an electronic heating element that is integrally formed with the air-fuel separation system may be used to heat fuel for preconditioning prior to air-fuel separation, i.e., the heating element may be disposed upstream in a flow pathway with respect to the air-fuel separation system. The electronic heating element may be operably configured to receive electricity from a source external to a vehicle on which the air-fuel separation system is installed, or it may be adapted internally to receive electricity from an on-board electrical generator or alternator.
Another such aspect involves the use of check valves having a coil spring and a valve member, wherein the valve member has a shaft received within the coil spring and a semispherical head connected to the shaft. This assembly may be provided as a retrofit assembly to existing systems, such as the aforementioned FUEL PREPORATOR®, to prevent or remediate failure of prior spring and ball valves due to groove wear under conditions of long-standing use.
Another such aspect involves the water separator. To operate properly the device must have an unrestricted flow of fuel that is relatively free of water and foreign objects that could render the transfer pump inoperative. Water separators can be made of many different materials such as cellulose, microglass, wire or synthetic screen or combinations thereof. Many fuel filters are marketed as combination fuel filter-water separators. Many of these products plug quickly with use and restrict fuel flow. Should any of these products find their way into use on an air separator device, they could cause operational failures of th
Miller Carl S.
Suelthaus & Walsh, P.C.
LandOfFree
Fuel delivery system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel delivery system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel delivery system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3259966