Patent Application
20100268443
The present invention relates to liquid fuel combustion and, more particularly, to the preparation of liquid fuels to combustion in a combustion chamber of internal combustion engines.
In existing internal combustion engines such as diesel and gasoline engines, as well as other types of engines a fuel is injected into a combustion chamber at high pressure. A charge of the fuel is injected by means of solenoid injectors controlled by an on-board microcomputer and connected to a common rail. The on-board microcomputer controls injection timing and duration as well as an injection pressure by means of a two-stage main fuel pump. To provide a better fuel atomization after injection into combustion chamber the fuel pressure in the common rail upstream the injectors is maintained at high level, e.g., in diesel engines the fuel pressure is maintained at 2000 . . . 2400 bars.
Currently different approaches are used to improve the fuel atomization and dispersion in the combustion chamber after injection. For example, they use joint injection of hydrogen or natural gas with gasoline, in other system a compressed air stream is directed to the fuel spray injected in the combustion chamber. There is also an approach where fuel and air are induced with the same charge to reduce a coalescence of the fuel microdroplets after the injection.
There are known attempts to disperse fuel by dissolving some gas, e.g., air or carbon dioxide, in the liquid fuel and subsequently injecting this solution into the combustion chamber. When injected into the combustion chamber the dissolved gas is released from the solution providing very fine dispersion of the liquid fuel. In U.S. Pat. No. 6,273,072 (Knapstein et all) and U.S. Pat. No. 7,011,048 (Gurin et all) they described methods and devices for implementation and utilization of the abovementioned effect. The described systems require special devices that supposed to work within a certain range of parameters and at the same time certain conditions should be observed to provide the fuel/gas solution to the combustion chamber in proper condition. In practice it is difficult to satisfy both of these requirements simultaneously, and the achieved effect is not stable at various loads.
An object of this invention is to provide a method and apparatus which overcomes the abovementioned disadvantages and which provides for further improvement in the fuel injection into the combustion chamber that reduces fuel consumption as well as emissions.
In accordance with invention there are provided technical solutions for different types of fuel systems. The fuel is preparing for injection and combustion in a special device, an absorber, where the fuel is contacting with the gas or gasses. The gas pressure inside the absorber is maintained higher than the fuel pressure supplied to the absorber; the gas is dissolved in the liquid fuel forming a unsaturated fuel solution having no free gas phase. The resulted fuel solution is guided to a main fuel pump that further increases the pressure of the fuel solution providing no free gas phase. Upon injection in the combustion chamber in addition to the hydrodynamic fuel atomisation a violent degassing takes place providing continuous chain breaking of fuel microdroplet to a fine “nano” sizes. The combination of the gas desorption from the fuel solution with the hydrodynamic breaking-up of the injected fuel provides a fundamentally new process of the fuel atomization in the combustion chamber. the fuel microdroplets continuously break up to significantly small sizes providing an extremely high interfacial curvature and liquid vapour (fuel) pressure increases in as much as 8-10 times. This effect is described by the Kelvin equation and it is well known that the quicker liquid fuel evaporates the more rapid and effective the combustion of the gasoline or diesel is. One more important additional effect of the new injection process: the continuous chain breaking of the fuel droplets caused by the gas desorption prevents coalescence of the droplets and formation of the fuel film on the walls of the combustion chamber. As a result more fuel surface is available for contact with the air. Thus the fuel burns faster and more complete giving less harmful emissions.
Taking into account this and other objects a method of fuel activation and supplying into the combustion process is presented. The method comprises steps of:
With this and other objects in view there is provided, in accordance with the invention, a system for liquid fuel activation and feeding it to the combustion chamber for combustion, comprising:
The system and method of operation of the invention with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
The activation system according to the present invention consists of two subsystems: a conditioning subsystem and a gas preparation subsystem.
The conditioning subsystem comprises an absorber 10, a feeding pump 11, a differential pressure regulator 12, a jet pump 15. Three-way valves 14 and 16 are used to change from standard (base) fuel supply system to the conditioning subsystem and vice versa. Check valves 18, 19 prevent fuel to flow in wrong direction.
The gas preparation subsystem comprises a reactor 13 and two air and exhaust gases supply lines. Air supply line includes a filter 28, a compressor 29, a pressure regulator 30, and an oxygen enrichment membrane filter 31 whereas exhaust gases line includes a filter 22, a cooler 23, a compressor 24 and a pressure regulator 25.
The gas mixture is prepared in the reactor 13 by mixing the exhaust gases as sources of CO2 with oxygen enriched air that is formed after ambient air passes through the oxygen enrichment membrane filter 31. Mixing of two gas streams in equal portions by weight is provided by pressure regulators 25 and 30 having common control line. Required pressure of the gas mixture is provided by compressors 24 and 29 and controlled by the pressure regulators 25 and 30.
The fuel from fuel tank 17 is delivered by feeding pump 11 to the nozzles mounted in the absorber 10. The feeding pump 11 provides the fuel pressure P1. The gas mixture from the reactor 13 is guided to the gas inlet port of the absorber 10 under gas pressure P2 which is controlled by pressure regulator 17. Pressure regulator 32 maintains the gas pressure inside the absorber 10 at set level P2. The gas pressure P2 is set up lower than the fuel pressure P1 providing satisfactory working condition for the fuel dispersing by the nozzle in absorber 10. The dispersing of fuel in gas results in achieving significant amount of gas being dissolved in fuel. An outlet port located at the bottom of the absorber 10 is fluidically connected to the inlet port of the main fuel pump 2. The differential pressure regulator 12 positioned in the connection line between the absorber 10 and main fuel pump 2 temporary reduces the fuel solution pressure. The reduced pressure transfers the fuel solution into the state of oversaturated solution thus facilitates the gas desorption from the fuel by destroying temporary sorption links between liquid and gas molecules. This step improves effectiveness of the desorption process at injection and improves the atomization of the injected fuel charge. In addition the differential pressure regulator 12 compensates for pressure pikes arisen during the absorber 10 operation. Main fuel pump 2 again increases the pressure of the fuel solution as much as 2 times and returns the fuel solution in the state of unsaturated solution. In such state the main fuel pump 2 delivers the fuel solution to the common rail 1 and unit injectors (not shown) for combustion.
It is well known that the gas solubility in liquid is proportional to the partial pressure of the gas over the liquid surface and the concentration of the gas dissolved in liquid is in inverse proportion to the liquid temperature. As fuel solution parameters in supply line is maintained higher than parameters in the combustion chamber at injection in addition to hydrodynamic breaking of fuel stream by injector the gas dissolved in the fuel solution violently escapes from the liquid thus providing additional atomization of the fuel to more finest aerosol as well as even distribution over the volume of the combustion chamber. The faster evaporation on superfine fuel microdroplets at high temperature present in the combustion chamber provides speedy propagation of the flame front. This way faster and more efficiently burnt fuel delivers more energy at optimal piston and crankshaft position. As a result it takes less fuel to produce the same amount of power, as well as provides reduction of emissions.
Since the main fuel pump 2 delivers more fuel than the internal combustion engine can consume to produce useful power recirculation lines are provided for returning excess fuel. Recirculation fuel solution flows from first stage of the main fuel pump 2 and from the common rail 1 are merged in the jet pump 15: recirculation fuel solution flow from common rail having higher pressure is guided to the nozzle of the jet pump 15; the ejected flow creates low pressure in the mixing chamber and recirculation flow from first stage of the main fuel pump 2 is sucked into the mixing chamber of the jet pump thus providing lower pressure at the drainage port of the main fuel pump and better conditions for gas separation.
In another embodiment (
To shut the engine out or at idle operation the fuel supply should be switched to the base mode using three-way valves 14 and 16 and shutting out the fuel supply to the absorber 10.
Before parking the vehicle for a long period of time the cylinder head and the fuel supply should be flushed from conditioned fuel by operating the engine on the base unconditioned fuel for about 30-90 seconds.
The present invention is not to be construed as limited to the forms shown which are to be considered illustrative rather than restrictive.
| Number | Date | Country | |
|---|---|---|---|
| 61212671 | Apr 2009 | US |
