Currently fuel injection systems, used on diesel engines, are required to carry out two necessary functions: atomize the fuel into the many small particles needed for rapid and efficient burning of the fuel; and distribute these many fuel particles approximately uniformly in the air mass in the engine combustion chamber, so that each fuel particle has access to the air needed for combustion. When lower cost, higher viscosity, fuels are to be used, higher fuel injection pressures, and resulting higher fuel jet velocities are needed, in order to achieve the needed small fuel particle sizes. At higher velocity, the fuel jet penetrates deeper across the engine combustion chamber. Thus to avoid fuel jet impact on the engine cylinder wall, larger engine cylinder diameter is needed when higher viscosity fuels are to be used.
For these reasons low cost, high viscosity, petroleum residual fuels are currently used only in large bore, very slow speed, marine diesel engines for cargo ships. The small bore high speed diesel engines, and medium bore medium speed diesel engines, used throughout our commercial surface transportation system, are obliged to use expensive, low viscosity, petroleum distillate fuels to avoid inefficient fuel combustion.
The residual fuel content of recently developed crude oil deposits has tended, on average, to increase with the passage of time. For example, the recently developed, and very large, Athabaska tar sands yield a crude oil which is essentially wholly residual tar fuel. Suitable distillate type fuels can be prepared from Athabaska tar and other residual fuels but substantial stock losses and energy efficiency losses result from the required tar processing.
A method of operating a major portion of our surface transportation industry on low cost tars and residual petroleum fuels, in place of high cost distillate petroleum fuels, increasingly in short supply, would be a substantial national benefit.
Preatomizing a high viscosity tar or residual fuel, outside the diesel engine combustion chamber, into a slurry fuel comprising many small fuel particles, preatomized into a suspension within a continuous water phase, relieves the fuel injection system of the duty of atomizing the high viscosity fuel. The slurry fuel injection system can then be primarily designed to distribute these many small fuel particles, within the compressed combustion air mass in the engine cylinder, for optimum efficiency of combustion and engine work output.
During slurry fuel injection into the engine combustion chamber, aerodynamic forces will break up the slurry fuel jet into separate primary slurry fuel droplets, each of which will contain many separate preatomized fuel particles. The water phase evaporates from the surface of the slurry fuel primary droplets, thus leading to reagglomeration of the preatomized fuel particles into larger particles.
To avoid this undesirable reagglomeration of fuel particles, as well as to accelerate the water evaporation step, water soluble supplementary atomizing gas is dissolved into the continuous water phase of the slurry, at high pressure in a contactor chamber added to the common rail fuel injection system of this invention. When slurry fuel, containing supplementary atomizing gas, dissolved into the continuous phase at the high pressure in the contactor chamber, is injected into the relatively low pressure in the engine combustion chamber, the supplementary atomizing gas will expand out of solution in each primary slurry droplet, and separate the preatomized fuel particles, thus preventing undesirable reagglomeration of fuel particles.
In modern common rail fuel injection systems, two separate valves are interposed between the high pressure common rail and the fuel injector spray nozzle in order to take pressure off of the fuel injection valve between injections, and thus reduce the possibility of fuel leakage during engine exhaust and intake. Both the fuel injection valve and the separate fuel shut off valve are often opened and closed using the engine fuel from the common rail as a driving fluid. For the slurry fuel injection system of this invention a separate hydraulic fluid, at high pressure in a hydraulic fluid common rail, is used as the driving fluid for the opening and closing of both the fuel injection valve and the fuel shut off valve. Slurry fuel containing dissolved supplementary atomizing gas is thus not used for driving the fuel injection valve and the fuel shut off valve of this invention and the loss of compressed atomizing gas which would otherwise result is avoided.
After each fuel injection, any fuel trapped between the closed fuel injection valve and the closed fuel shut off valve is to be depressurized to avoid fuel leakage. For conventional. distillate petroleum fuels such depressurization, even of a large fuel volume, does not create a problem. But, for a slurry fuel containing dissolved supplementary atomizing gas, either depressurization is incomplete due to pressure created by expanding atomizing gas, or, if the fuel injection valve is last to close, any appreciable trapped slurry fuel portion loses the benefit of supplementary atomizing gas before being injected into the engine cylinder. For the slurry fuel injection system of this invention a special double valve fuel injector is used wherein the fuel shut off valve and fuel injection valve, while operated separately, have a common sealing surface edge. As a result the volume of fuel trapped between these two valves can be vanishingly small.
In this way the economic and energy independence benefits of using low cost, high viscosity, residual fuels, and tar fuels, in the smaller bore, higher speed diesel engines used in our surface transportation industries can be fully realized. These surface transportation industries include railroads, tug and barge carriers, open pit mining operations, and farm plowing and harvesting operations.
The common rail slurry fuel injection system of this invention comprises a diesel engine fuel injection system, suitable for the efficient injection, of slurry fuels containing dissolved supplementary atomizing gas, into the combustion chamber of a diesel engine. This slurry fuel injection system comprises the following principal elements:
1) A combined double valve, fuel injector has a fuel injection valve, and a separate fuel shut off valve, with two separate valve driver systems for separately opening and closing the valves. One of the valve seating surfaces on the fuel injection valve shares a common edge with one of the valve seating surfaces on the fuel shut off valve.
2) A slurry fuel high pressure common rail comprises also a contactor chamber, within which high pressure slurry fuel from a slurry fuel pump, is contacted with supplementary atomizing gas, also at high pressure. Soluble atomizing gas thus becomes dissolved at high pressure into the continuous phase of the slurry fuel.
3) A non-fuel hydraulic fluid high pressure common rail receives hydraulic fluid from a high pressure hydraulic fluid pump. This high pressure hydraulic fluid, from the hydraulic fluid common rail, via a fuel injection valve pressure and vent valve, is used to operate the valve driver of the fuel injection valve, and to separately operate the valve driver of the fuel shut off valve, via a fuel shutoff pressure and vent valve.
4) A fuel injection timer system separately times the application of high pressure hydraulic fluid to the valve drivers of the fuel injection valve, and the fuel shut off valve, in order to separately time the start of fuel injection, into the engine combustion chamber, to be at best efficiency timing for the engine cycle, and to adjustably stop the fuel injection, in order to control fuel quantity injected per engine cycle, and thus to control engine torque.
Details of these principal elements, and other related elements are presented hereinbelow:
By using high pressure, non-fuel, hydraulic fluid to operate the fuel injectors, instead of high pressure slurry fuel, containing dissolved atomizing gas, loss of high pressure atomizing gas during valve driver operation, is avoided, thus reducing the power loss to the compression of the atomizing gas.
The common valve seating edges, for the fuel injection valve, and the fuel shut off valve, can be used to assure that only that slurry fuel injected into the diesel engine combustion chamber undergoes the depressurization, and consequent atomizing gas expansion out of the continuous phase, needed to carry out the supplementary atomizing of each slurry fuel droplet.
Various types of slurry fuels can be used advantageously in combination with the common rail slurry fuel injection system of the invention, of which the following are examples:
a) Preatomized petroleum residual fuel particles, suspended in a continuous water phase, with a small number of high cetane number petroleum distillate particles as igniter fuel;
b) Preatomized coal tar and tar liquids particles, from the devolatilization of bituminous coals, suspended in a continuous water phase, with a small number of high cetane number petroleum distillate particles as igniter fuel;
c) Preatomized tar and tar liquids particles, from the devolatilization of nonfood farm harvest biomass material, suspended in a continuous water phase, with a small number of high cetane number petroleum distillate particles as igniter fuel;
Example methods of preparing these slurry fuels are described in my following US Patent
Applications, and this material is incorporated herein by reference thereto:
1) U.S. Pat. No. 7,677,791, entitled, Rotary Residual Fuel Slurrifier, filed 30 Apr. 2007; issued 16 Mar. 2010;
2) U.S. patent application Ser. No. 12/583,448, entitled, Rotary Tar Slurrifier, filed 21 Aug. 2009;
3) U.S. patent application Ser. No. 12/454640, entitled, Engine Fuels From Coal Volatile Matter, filed 21 May 2009;
4) U.S. patent application Ser. No. 12/590,333, entitled, Cyclic Batch Coal Devolatilization Apparatus, filed 6 Nov. 2009;
5) U.S. patent application Ser. No. 12/653189, entitled, Engine Fuels from Coal and Biomass Volatile Matter, filed 10 Dec. 2009, a continuation-in-part of Ser. No. 12/454,640;
Various types of hydraulic fluids can be used with the common rail slurry fuel injection system of this invention, of which the following are examples:
d) Conventional hydraulic fluids as used in actuators on earth moving machinery;
e) Hydraulic brake fluid as widely used in car and truck braking systems;
f) Well filtered engine crankcase lubricating oil;
The supplementary atomizing gas is selected to be at least partially, and preferably largely, soluble in the continuous phase of the slurry fuel. Many gases are at least partially soluble in a water continuous phase, such as the following examples:
g) Carbon dioxide is highly water soluble, and only the impurities would be insoluble;
h) The oxygen portion of atmospheric air is moderately water soluble, but the larger nitrogen portion is only slightly water soluble;
i) The carbon dioxide and oxygen portions of diesel engine exhaust gas are soluble in water and are readily available from the diesel engine but require appreciable cooling.
j) Commercial purity oxygen will be largely water soluble, but may present an explosion hazard in the presence of fuels at the high pressures in the slurry fuel common rail;
Where distillate petroleum fuel is the continuous phase of a slurry fuel, natural gas can be efficiently used as a supplementary atomizing gas;
A cross sectional drawing of a combined double valve fuel injector is illustrated schematically in
These elements are sealably enclosed within the stationary fuel injector body, 11. High pressure slurry fuel, containing dissolved atomizing gas in the continuous phase, enters the fuel manifold, 7, via the slurry fuel connector, 8, from a high pressure slurry fuel common rail, and flows into the intershaft fuel flow passage, 9, via fuel passages, 10.
Admission of high pressure hydraulic fluid, from a hydraulic fluid common rail, via connection, 12, to the opening side, 13, of the fuel shut off valve driver piston, 4, opens the fuel shut off valve, 5, against the driver spring, 158, and admits high pressure slurry fuel to the fuel injector valve, 2.
Subsequent admission of high pressure hydraulic fluid, from the hydraulic fluid common rail, via connection, 14, to the opening side, 15, of the fuel injection valve driver piston, 1, opens the fuel injection valve, 2, against the driver spring, 157, and admits high pressure slurry fuel to the fuel injection nozzle, 16, and from there into the engine combustion chamber, 17.
Adjustable venting of hydraulic fluid from the opening side, 13, of the fuel shut off valve driver piston, 4, via connection, 12, allows the driver spring, 158, to close the shut off valve, 5, against a back seat, 18, on the fuel injection valve head, 19, and slurry fuel flow to the fuel injection valve, 2, and hence into the engine combustion chamber, 17, is stopped. The time interval between a fixed opening time of the fuel injection valve, 2, and the subsequent adjustable closing of the fuel shut off valve, 5, can be varied as a method of adjusting the fuel quantity injected into the engine combustion chamber during each engine cycle, in order to adjust engine torque output.
The opening lift of the fuel shut off valve, 5, is to be appreciably greater than the opening lift of the fuel injection valve, 2, so that opening of the fuel injection valve does not close the fuel shut off valve.
Subsequent venting of hydraulic fluid from the opening side, 15, of the fuel injection valve driver piston, 1, via connection, 14, allows the driver spring, 157, to close the fuel injection valve, 2. The fuel shut off valve, 5, remains closed while moving down with the closing fuel injection valve head, 19, to force essentially all slurry fuel out of the bottom of the fuel injector, beyond the fuel shut off valve. The clearance between the lower end, 20, of the fuel shut off valve, 5, and the fuel injector body, 11, when the fuel injection valve is closed, is finite but small. The two valve seating areas on the fuel injection valve head, 19, share a common outer radius, 21. With these arrangements, essentially the only slurry fuel undergoing depressurization, and the needed supplementary atomization due to expansion of atomizing gas out of the continuous phase, is that slurry fuel injected into the diesel engine combustion chamber, 17.
A pintle type fuel injection nozzle, 16, is shown in
Driver spring chambers are vented to atmosphere via vents, 22, and hydraulic fluid leakage is collected and returned via connections, 23, to the hydraulic fluid reservoir. Similarly slurry fuel leakage is collected and returned via connections, 24, to the slurry fuel tank.
The fuel shut off valve shaft also functions as a spring loaded piston and cylinder fluid accumulator to reduce pressure fluctuations within the intershaft fuel flow passage, 9, during fuel injection. A supplementary piston, cylinder, and spring fluid accumulator, as shown schematically on
Injection of slurry fuel into the diesel engine combustion chamber is to start at, or near, to best efficiency timing for the diesel engine cycle, by opening the fuel injection valve, the fuel shut off valve having been opened somewhat earlier. Two separate pressure and vent valves are operated by separate timer units, and the timer units are driven by the crankshaft for two stroke cycle engines, or by the camshaft for four stroke cycle engines.
An example diagram of mechanical pressure and vent valves, operated by camshaft driven timer cams, is illustrated schematically in
One fuel injection valve pressure and vent valve, 25, is shown opened to the hydraulic fluid pressure connection, 32, by the fuel injection valve timer cam, 26, on the fuel injection valve timer cam plate, 27, rotated by the engine camshaft, 28, at one half of engine RPM. High pressure hydraulic fluid thus acts on the opening side, 15, of the fuel injection valve driver piston, 1, to open the fuel injection valve, 2, and compress the driver spring, 157. Slurry fuel is then injected into the engine combustion chamber. Subsequently, when the cam follower, 30, is returned to the base circle, 31, of the cam plate, 27, the timer spring, 29, moves the pressure and vent valve, 25, to close the hydraulic fluid pressure connection, 32, and to open the hydraulic fluid vent connection, 33. The driver spring, 157, then closes the fuel injection valve, 2, and vents the spent hydraulic fluid back to the hydraulic fluid supply tank via the vent connection, 33. A single fuel injection valve timer cam and plate can also operate the pressure and vent valves for the other three engine cylinder fuel injectors of this
An entirely similar fuel shut off valve pressure and vent valve can be mechanically driven by the fuel shut off valve timer cam, 34, on the fuel shut off valve timer cam plate, 35, rotated by the engine camshaft, 28, via the helical spline sleeve and gear angular phase change unit, 38, 39, shown schematically in
As shown on
Other types of angular phase adjustors can be used for thus controlling engine torque as are well known in the art of mechanical phase adjustors.
In this way the slurry fuel shut off valve, 5, is timed relative to the slurry full injection valve, 2, as follows:
(1) Fuel shut off valve is opened before the fuel injection valve;
(2) The fuel injection valve is next opened at or near to best fuel efficiency timing for the diesel engine cycle;
(3) The fuel shut off valve is adjustably closed before closure of the fuel injection valve to control engine torque;
(4) The fuel injection valve is closed after closure of the fuel shut off valve.
Best efficiency timing of fuel injection can vary with engine speed. Thus for diesel engines operated over a wide speed range an angular phase adjustor may also be preferred between the fuel injection valve timer cam plate, 27, and the engine camshaft, 28, to be adjusted by an engine speed sensor.
Solenoid or solenoid and spring operators of the pressure and vent valve can be used for electrical slurry fuel timers, an example of which is shown schematically in
When the valve opener solenoid, 44, is alone energized by electric power, via connections, 46, the pressure and vent valve, 43, opens to only connect the hydraulic fluid pressure connection, 45, to the valve opening side, 15, of the fuel injection valve driver piston, 1, and high pressure hydraulic fluid, from the hydraulic fluid common rail, acts to open the fuel injection valve.
When the valve closer solenoid, 47, is alone energized by electric power, via connections, 48, the pressure and vent valve, 43, moves to only connect the hydraulic fluid vent connection, 49, to the opening side, 15, of the fuel injection valve driver piston, 1, and hydraulic fluid is forced out of the closing side, 15, by the fuel injection valve driver spring, 157, and the fuel injection valve closes.
A particular example fuel injection timing unit is shown schematically in
In this same way, the fuel injection valve timer disc, 50, with shutter openings crossing the light path between a lamp and a photocell, functions to open and close the fuel injection valve, 2.
A single fuel injection valve shutter disc, in combination with a separate single fuel shut off valve shutter disc, can serve all engine cylinders, with separate lamp and photocell units for each combustion chamber. All fuel injection valve lamp and photocell units are secured to a common fuel injection valve bracket, 63, and all fuel shut off valve lamp and photocell units are secured to a separate fuel shut off valve bracket, 64, and these brackets can be separately angularly adjusted about the centerline of the engine crankshaft, 52. All shutter openings are at the same radius as the light path between lamp and photocell. Where more than one shutter opening is used, the number of shutter openings is equal on both timer discs and the shutter openings on the full shut off valve timer disc have the same angular spacing as the corresponding shutter openings on the fuel injection valve timer disc. Shutter openings on the fuel shut off valve timer disc are angularly wider than the corresponding shutter openings on the fuel injection valve timer disc. Pulsed fuel injection can be obtained by use of several shutter openings on each timer disc. The start of fuel injection into the engine combustion chamber can be adjusted to best engine cycle efficiency timing by angular adjustment of the fuel injection valve bracket, 63, via lever, 65. The duration of fuel injection, and thus fuel quantity injected per engine cycle and hence the engine torque, can be adjusted by adjusting the phase angle between the fuel injection valve timer disc, 50, and the fuel shut off valve timer disc, 51, via the torque control lever, 66, shown in section B-B of
(1) The fuel shut off valve is opened before the fuel injection valve;
(2) The fuel injection valve is next opened at or near best fuel efficiency timing for the diesel engine cycle;
(3) The fuel shut off valve is adjustably closed before closure of the fuel injection valve to control engine torque;
(4) The fuel injection valve is closed after closure of the fuel shut off valve.
The pressure and vent valve, 43, shown in
The slurry fuel injection system shown schematically in
(1) The combustion chambers in each of the four engine cylinders, 79, are equipped with a combined double valve fuel injector, 80, similar to that illustrated in
(2) A mechanical cam operated timer unit, 81, is driven by the engine camshaft, 28, and is similar to that illustrated in
(3) High pressure hydraulic fluid is delivered to the pressure connections of each pressure and vent valve from the high pressure common rail, 83, which receives hydraulic fluid from the hydraulic fluid tank, 84, via the high pressure hydraulic fluid pump, 85, driven from the engine camshaft, 28, and controlled by the pressure sensor, 86, on the high pressure hydraulic fluid common rail, 83. Vented hydraulic fluid from the pressure and vent valves is returned to the hydraulic fluid tank, 84, via vent pipe, 87, to complete the hydraulic fluid cycle.
(4) The slurry fuel common rail, 88, with contactor chamber, 89, and supplementary atomizing gas inlet, 90, is similar to that described in my U.S. Pat. No. 7,418,927B2, issued 2 Sep. 2008, and this material is incorporated herein by reference thereto. Slurry fuel from the slurry fuel tank, 91, is delivered into the contactor chamber, 89, by the slurry fuel pump, 92, driven by the engine crankshaft, 93, via the flow divider, 94. The flow of slurry fuel is thus divided into a portion, delivered via connection, 95, into the upper portion of the contactor chamber, 89, and another portion, delivered via connection, 96, into the lower portion of the contactor chamber, 89, and below the slurry fuel level, 97, maintained in the contactor chamber, 89, by the fluid level sensors, 98, and slurry fuel pump, 92, controller, 99.
(5) Atmospheric air is used as supplementary atomizing gas for this
(6) The downflowing slurry fuel portion thus becomes approximately saturated with oxygen in the continuous phase and is then blended into that slurry fuel portion delivered below the slurry fuel level, 97, in the contactor chamber. In this final blended slurry fuel the continuous water phase is less than saturated with dissolved oxygen, and gas expansion can be avoided throughout the high pressure slurry fuel piping, until the slurry fuel is injected into the lower pressures in the engine combustion chamber.
(7) Slurry fuel, with supplementary atomizing gas, thusly dissolved into the continuous phase, is delivered to each slurry fuel injector, 80, from the slurry fuel common rail, 88. Slurry fuel injection into each engine combustion chamber starts when the fuel injection valve is opened by the timer unit, 81, and ends when the fuel shut off valve is closed by the timer unit, 81.
(8) Instead of the back pressure valve, 104, a work recovery engine can be used to control contactor chamber pressure, resulting in improved fuel efficiency as is shown on
The slurry fuel injection system shown schematically in
(1) The combustion chamber in each of the four engine cylinders, 109, are equipped with a combined double valve fuel injector, 80, similar to that illustrated in
(2) An electrical fuel injection timer unit, 110, using a lamp, photocell, and timer discs power pulse generator, is driven by the engine crankshaft, 111, and is similar to that illustrated in
(3) High pressure hydraulic fluid is delivered to the pressure connections of each pressure and vent valve from the high pressure common rail, 113, which receives hydraulic fluid from the hydraulic fluid tank, 114, via the high pressure hydraulic fluid pump, 115, driven from the engine crankshaft, 111, and controlled by the pressure sensor, 116, on the high pressure hydraulic fluid common rail, 113. Vented hydraulic fluid from the pressure and vent valves is returned to the hydraulic fluid tank, 114, via vent pipe, 117, to complete the hydraulic fluid cycle;
(4) The slurry fuel separate contactor chamber, 118, for contacting slurry fuel with supplementary atomizing gas, is similar to that described in my U.S. Pat. No. 7,281,500B1, issued 16 Oct. 2007, and this material is incorporated herein by reference thereto. Slurry fuel from the slurry fuel tank, 119, is delivered into the upper portion of the contactor chamber, 118, by the slurry fuel pump, 120, driven by various drivers, such as an electric motor or the engine crankshaft, 111. The pump, 120, is controlled by the sensors, 121, of slurry fuel level, 122, within the contactor chamber, 118, to maintain an essentially constant fluid level therein, well above the midheight of the contactor chamber.
(5) High pressure and high purity carbon dioxide is used as supplementary atomizing gas, for this
Insoluble impurities in the carbon dioxide gas supply, 123, will accumulate in the space, 128, above the slurry fuel level, 122, and can be periodically or continually discharged via an adjustable gas bleed flow restrictor, 129. Carbon dioxide is highly soluble in water and the continuous water phase of the slurry fuel leaving the bottom, 130, of the contactor chamber, 118, is very nearly saturated with supplementary atomizing gas at contactor chamber pressure.
(6) Slurry fuel, with thusly dissolved carbon dioxide gas, is pumped into a higher pressure in the slurry fuel common rail, 131, by the engine crankshaft, 111, driven common rail slurry fuel pump, 132, and is delivered via the common rail, to each slurry fuel injector 80. The common rail pump, 132, is controlled by the controller, 133, responsive to the common rail pressure sensor, 134, to maintain an essentially constant pressure in the slurry fuel common rail. This slurry fuel common rail pressure is essentially the pressure at which fuel is injected by the slurry fuel injector, 80, into the engine combustion chamber. Since common rail pressure exceeds contactor chamber pressure the slurry fuel in the common rail is no longer saturated, and the gas expansion can be avoided throughout the common rail slurry fuel piping, until the slurry fuel is injected into the lower pressure in the engine combustion chamber.
(7) Slurry fuel injection into each engine combustion chamber starts when the fuel injection valve is opened by the electrical timer unit, 66, and ends when the fuel shut off valve is closed by the electrical timer unit, 66.
(8) Contactor chamber pressure, while less than common rail pressure, is nevertheless appreciably greater than maximum pressure in the engine combustion chamber.
The slurry fuel injection system shown schematically in
(1) The combustion chamber in each of the four engine cylinders, 136, are equipped with a combined double valve fuel injector, 80, similar to that illustrated in
(2) An electronic fuel injection timer unit, 137, is timed by the engine crankshaft, 138, and energized by an electric power source, 139. The pressure and vent valves, 43, are solenoid driven, as illustrated in
(3) High pressure hydraulic fluid is delivered to the pressure connections of each pressure and vent valve from the high pressure common rail, 113, which receives hydraulic fluid from the hydraulic fluid tank, 114, via the hydraulic fluid high pressure pump, 115, driven from the engine crankshaft, 138, and controlled by the pressure sensor, 116, on the high pressure hydraulic fluid common rail, 113. Vented hydraulic fluid from the pressure and vent valves is returned to the hydraulic fluid tank, 114, via vent pipe, 117, to complete the hydraulic fluid cycle;
(4) The slurry fuel contactor chamber, 142, for contacting slurry fuel with supplementary atomizing gas, is open flow connected to the high pressure slurry fuel common rail, 143. Slurry fuel from the slurry fuel tank, 144, is delivered into the upper portion of the contactor chamber, 142, by the high pressure slurry fuel pump, 145, driven by the engine crankshaft, 138. Slurry fuel is delivered into the contactor chamber above the packing material, 151, therein, and flows downward over the large area of the packing material into the bottom portion of the contactor chamber. The pump, 145, is controlled by the sensors, 146, of slurry fuel level, 147, within the contactor chamber, 142, to maintain an essentially constant fluid level therein, below the level, 148, at which supplementary atomizing gas is delivered into the lower portion of the contactor chamber, 142.
(5) Carbon dioxide gas is used as supplementary atomizing gas, for this
(6) A high and essentially constant pressure is maintained within the contactor chamber, 142, and the slurry fuel common rail, 143, by the controller, 152, of the supplementary atomizing gas compressor, 150, responsive to the pressure sensor, 153, of contactor chamber pressure. Gas compressor intercoolers, and a final gas cooler, 154, can be used to maintain a low temperature of the carbon dioxide gas going in to the contactor chamber, in order to improve gas solubility into the continuous water phase of the slurry fuel. Contactor chamber and common rail pressure is to be essentially equal to fuel injection pressure.
(7) Slurry fuel injection into each engine combustion chamber starts when the fuel injection valve is opened by the electronic timer unit, 137, and ends when the fuel shut off valve is closed by the electronic timer unit, 137.
The interconnections between the double valve, 11, the two pressure and vent valves, 25, 72, with drivers and timers, 26 and 27, 34 and 35, as driven from the diesel engine camshaft, 28, of a four stroke cycle diesel engine, are illustrated on
When the fuel injection valve, 2, cam lifter, 26, opens its pressure and vent valve, 25, to admit high pressure hydraulic fluid from the high pressure hydraulic fluid common rail, 68, via the connections, 32, 14, to the pressure side, 15, of the fuel injection driver piston, 1, the fuel injection valve 2, is opened. When the cam follower, 30, of the pressure and vent valve, 25, returns to the base circle, 31, of the cam plate, 27, the pressure and vent valve, 25, vents hydraulic fluid, from the pressure side, 15, of the fuel injection valve driver piston, 1, into the hydraulic fluid tank return line, 69, via connection, 33. The driver spring, 157, then closes the fuel injection valve, 2.
In similar fashion the fuel shutoff valve, 5, is opened by high pressure hydraulic fluid, and closed by venting of hydraulic fluid, via the fuel shutoff valve, 5, pressure and vent valve, 72, as operated by the cam lifter, 34, of the cam plate, 35, driven from the engine camshaft, 28, via the angular phase change unit, 38, 39, shown in
The cam plates, 27, and 35, are timed relative to each other so that:
(a) The fuel shutoff valve, 5, is opened before the fuel injection valve, 2, and high pressure slurry fuel from the slurry fuel common rail, 131, is supplied to the still closed fuel injection valve, 2, via connection, 8.
(b) The fuel injection valve, 2, is next opened, near best fuel efficiency engine cycle timing, and high pressure slurry fuel is injected into the compressed air in the engine combustion chamber, 17. Fuel combustion commences therein after an ignition delay time interval.
(c) The fuel shutoff valve, 5, is subsequently closed an adjustable camshaft, 28, angle of rotation following the opening of the fuel injection valve, 2, thus stopping the injection of slurry fuel into the engine combustion chamber, 17. This adjustable camshaft, 28, angle of rotation interval between the opening of the fuel injection valve, 2, and the closing of the fuel shutoff valve, 5, functions to adjust the duration of slurry fuel injection into the engine combustion chamber, 17, and thus the quantity of slurry fuel injected thereinto, and thus the engine torque output. This adjustment of the camshaft, 28, angle of rotation interval is done by moving the helical spline sleeve, 38, relative to the helical gear, 39, via the engine torque control lever, 40, as shown in
(d) The fuel injection valve, 2, is finally closed and a single engine cycle is thus carried out.
Wholly mechanical components are shown in
When a slurry fuel, containing supplementary atomizing gas dissolved thereinto at high contactor chamber pressure, is injected into a diesel engine combustion chamber, final atomizing occurs in two steps. The high velocity slurry fuel jet is atomized as it flows through the compressed air, by aerodynamic forces, into primary fuel droplets. These primary slurry fuel droplets are then broken apart by expansion of the supplementary atomizing gas out of solution from the continuous phase at the much lower pressures in the engine combustion chamber. The originally preatomized, and very small, fuel particles thus emerge fully separated and can undergo rapid and efficient combustion in the engine combustion chamber. In this way high viscosity residual fuels, and tars such as from the Athabaska tar sands, can be efficiently used in small and medium bore, moderate and high speed, diesel engines, as are widely used in our transportation, farming, and mining industries. This is a principal beneficial object of this invention.
Several combinations of preatomized fuel particles, suspended in a continuous phase containing dissolved supplementary atomizing gas, can be efficiently used as fuel for small and medium bore diesel engines, operated at high to medium speed, by use of the slurry fuel injection systems of this invention. The following examples illustrate several of these slurry fuel combinations.
(1) Residual petroleum fuel particles, suspended in a continuous water phase, with a small portion of high cetane number distillate petroleum igniter fuel particles, and using carbon dioxide, or air, or diesel engine exhaust, or oxygen as supplementary atomizing gas;
(2) Tar fuel particles from Athabaska tar sands, suspended in a continuous water phase, with a small portion of high cetane number distillate petroleum igniter fuel particles, and using carbon dioxide, or air, or diesel engine exhaust, or oxygen as supplementary atomizing gas;
(3) Coal tar fuel particles from coke ovens, suspended in a continuous water phase, with a small portion of high cetane number distillate petroleum igniter fuel particles, and using carbon dioxide, or air, or diesel engine exhaust, or oxygen as supplementary atomizing gas;
(4) Biomass tar fuel particles from the destructive distillation of nonfood farm harvest biomass material, suspended in a continuous water phase, with a small portion of high cetane number distillate petroleum igniter fuel particles, and using carbon dioxide, or air, or diesel engine exhaust, or oxygen as supplementary atomizing gas;
(5) Finely shredded nonfood farm harvest biomass particles suspended in a continuous distillate petroleum fuel phase, such as number two diesel fuel; and using methane, or natural gas, as supplementary atomizing gas;
(6) Conventional distillate diesel fuels from petroleum, and using compressed natural gas as supplementary atomizing gas to improve atomization and combustion efficiency;
(7) Conventional distillate diesel fuels into which soluble portions of several low cost tar fuels, such as from Athabasca tar sands, and also using compressed natural gas as supplementary atomizing gas to maintain efficient atomization of these higher viscosity fuels;
(8) Conventional distillate diesel fuels, into which finely divided solid biomass char particles, from devolatilization of non food farm harvest biomass, are suspended, and also using compressed natural gas as supplementary atomizing gas;
Some risk of explosion, internal to the slurry fuel common rail, the contactor chamber, and the fuel injectors, may exist when using supplementary atomizing gas containing oxygen, such as air, and particularly when using moderate purity oxygen gas.
Apparatus for preparing several of these slurry fuels is described in my following US Patent applications, now on file in the US Patent and Trademark Office:
(a) U.S. Pat. No. 7,677,791, entitled Rotary Residual Fuel Slurrifier, filed 30 Apr. 2007, issued 16 Mar. 2010.
(b) U.S. patent application Ser. No. 12/583,448, entitled Rotary Tar Slurrifier, filed 21 Aug. 2009.
(c) U.S. patent application Ser. No. 12/454,640, entitled, Engine Fuels from Coal Volatile Matter, filed 21 May 2009.
(d) U.S. patent application Ser. No. 12/590,333, entitled Cyclic Batch Coal Devolatilization Apparatus, filed 6 Nov. 2009.
(e) U.S. patent application Ser. No. 12/653,189, entitled Engine Fuels from Coal and Biomass Volatile Matter, filed 10 Dec. 2009.
This material is incorporated herein by reference thereto.
The residual fuel content of newly discovered crude oils has tended to increase with the passage of time. Indeed some large new oilfields, such as the Athabaska tar sands, yield a crude oil which is essentially wholly residual fuel. Distillate petroleum fuels can be prepared from these residual and tar fuels, but substantial fuel and energy losses result. Direct use of residual fuels in transportation engines is now confined to large bore, slow speed marine diesel engines. All other transportation engines currently require use of expensive distillate petroleum fuels, which are increasingly in reduced supply.
Preatomization of residual fuels, tars from tar sands, and tars from coal and biomass, into a suspension of very small fuel particles in a continuous water phase, is a promising method for efficiently using these fuels in small and medium bore, high and medium speed, diesel engines, which are the major power source for our critical transportation industry. A major step toward the energy independence needed for a sound national defense can be achieved in this way.
The invention described herein is related to my following US Patent Applications: (1) U.S. Pat. No. 6,444,000, entitled, Steam Driven Fuel Slurrifier, issued 8 Sep. 2002.(2) U.S. Pat. No. 7,677,791, entitled, Rotary Residual Fuel Slurrifier, issued 16 Mar. 2010.(3) U.S. patent application Ser. No. 12/583,448, entitled, Rotary Tar Slurrifier, filed 21 Aug. 2009. The above patents and applications describe apparatus for preatomizing high viscosity tars and residual fuels. (4) U.S. Pat. No. 7,281,500, entitled, Supplementary Slurry Fuel Atomizer and Supply System, issued 16 Oct. 2007.(5) U.S. Pat. No. 7,418,927, entitled, Common Rail Supplementary Atomizer for Piston Engines, issued 2 Sep. 2008.(6) U.S. patent application Ser. No. 12/011,569, entitled, Modified Common Rail Fuel Injection System, filed 19 Jan. 2008. The above patents and applications describe the use of contactor chambers and separate hydraulic fluid common rail for dissolving supplementary atomizing gas into the continuous phase of a slurry fuel. (7) U.S. patent application Ser. No. 12/454,640, entitled, Engine Fuels from Coal Volatile Matter, filed 21 May 2009.(8) U.S. patent application Ser. No. 12/590,333, entitled, Cyclic Batch Coal Devolatilization Apparatus, filed 6 Nov. 2009.(9) U.S. patent application Ser. No. 12/653,189, entitled, Engine Fuels from Coal and Biomass Volatile Matter, filed 10 Dec. 2009. These latter patent applications describe apparatus for deriving high viscosity fuels and tars, suitable for slurrification into slurry fuels from our large reserves of bituminous coal and also from non-food farm harvest biomass materials. The relation of several of these patents and applications to the Common Rail Slurry Fuel Injection system of this invention is described in the Description of the Preferred Embodiments.