Patent Application
20100095914
1. Field of the Invention
The present invention relates to internal combustion engines.
2. Description of Related Art
An embodiment of an internal combustion engine includes a cylinder, a piston, a crankshaft, a cylinder head (head), an intake valve and an exhaust valve. A position of the piston is generally referred to with reference to top dead center and/or bottom dead center. Top dead center occurs when the crankshaft extends the piston to a point closest to the head. At top dead center there is minimum volume in the cylinder between the piston and the head. Bottom dead center occurs when the crankshaft moves the piston to a maximum distance from the head. At bottom dead center there is maximum volume in the cylinder between the piston and the head. As the crankshaft rotates, the piston position may be described in terms of degrees (of the crankshaft) before or after top dead center. The phrase “after top dead center” means the piston is moving away from the head when the engine is rotating in a forward direction. Similarly, “before top dead center” means the piston is moving toward the head. For example, ten degrees before top dead center describes the piston as moving toward the head and an angle of ten degrees between the crankshaft and the position of the crankshaft when the piston is at top dead center. Similarly fifteen degrees after top dead center refers to the piston moving away from the head and an angle of fifteen degrees. Thus, at 90 degrees after top dead center, the piston would be moving away from the head and at a position halfway between the minimum travel and maximum travel from the head. Similarly, at 60 degrees before top dead center (120 degrees after bottom dead center), the piston would be moving toward the head and at a position one quarter of the way between from minimum distance to maximum distance from the head. The volume of the cylinder would be about one quarter of the maximum volume. If the engine rotates in a reverse direction, the piston moves away from the head before top dead center and toward the head before top dead center.
An internal combustion engine includes a compression stroke, a combustion stroke, an exhaust stroke and in intake stroke. During the intake stroke, the piston draws an air/fuel mixture through the intake valve into the cylinder between top dead center (or a few degrees after top dead center) and bottom dead center. Upon reaching bottom dead center, the piston begins the compression stroke. The intake and exhaust valves are both closed as the piston moves from bottom dead center towards top dead center compression the air/fuel mixture between the piston and the head. At top dead center, the volume of the cylinder is minimum and the air/fuel mixture reaches maximum compression. Thus, compression is performed by the piston inside the cylinder. In a gasoline engine, a spark plug may ignite the fuel/air mixture at top dead center or a few degrees before or after top dead center to initiate combustion. In a diesel engine, the compression may increase the temperature of the fuel/air mixture adiabatically to an auto combustion temperature. Auto combustion temperature is a temperature at which a fuel/air mixture can combust spontaneously at a particular pressure. Combustion is accomplished in a compression-ignition or fuel-injected engine by injecting fuel into the cylinder when the cylinder is a few degrees before top dead center. Combustion of the fuel/air mixture produces a combustion gas that drives the piston away from the head through the combustion stroke from top dead center to bottom dead center. As the fuel burns volume of the cylinder increases, the combustion gas expands to become exhaust gas. At about bottom dead center the exhaust valve opens to release the exhaust gas. During the exhaust stroke, the piston moves from bottom dead center toward the head pushing out the exhaust gas through the exhaust valve. Upon reaching top dead center most or all of the exhaust gas has been removed and the next intake stroke begins. The intake stroke draws in fresh air and fuel is injected into the cylinder a few degrees before or after top dead center using a fuel injector. Fuel for internal combustion engines includes gasoline, diesel, alcohol, a blend of gasoline and alcohol, and/or diesel and natural gas.
Various embodiments include a system comprising a compressor configured increase a pressure and temperature of a gas to produce a compressed gas and to maintain a continuous pressure and temperature of the compressed gas at, for example, more than four times ambient pressure and greater than a combustion temperature of a fuel. The internal combustion engine includes a cylinder configured to receive the compressed gas from the compressor at the increased pressure and temperature, a piston disposed in the cylinder, and an intake valve disposed between the compressor and the cylinder. The intake valve can be configured to open based on a position of the piston for admitting the compressed gas into the cylinder. The fuel source can be configured to provide the fuel to the cylinder.
Various embodiments include a method comprising compressing a gas outside of an internal combustion engine, maintaining a pressure of the compressed gas continuously at, for example, greater than four times ambient pressure during, for example, more than four strokes of the internal combustion engine. Next, the compressed gas is provided to a cylinder of the internal combustion engine after a piston in the cylinder passes top dead center during a power stroke and a fuel is provided to the cylinder before the piston reaches bottom dead center during the power stroke. A combustion product is produced in the cylinder from the compressed gas and the fuel during the power stroke. Next the piston is driven in the cylinder using the combustion product during the power stroke and an exhaust gas is released from the cylinder during an exhaust stroke immediately following the power stroke. The compressed gas is provided to the cylinder of the internal combustion after the piston passes top dead center during a power stroke immediately following the exhaust stroke.
Various embodiments include a method comprising opening an intake valve of a cylinder of an internal combustion engine and receiving a compressed gas having a temperature of a fuel combustion temperature. The compressed gas is received through the open the intake valve from outside of the internal combustion engine. The intake valve is closed after a piston in the cylinder passes top dead center of a power stroke and fuel received before the piston reaches bottom dead center of the power stroke. Combustion gas is produce in the cylinder from the compressed gas and the fuel before the piston reaches bottom dead center of the power stroke. The combustion gas drives the piston in the cylinder toward bottom dead center. The exhaust valve is opened and the piston pushes exhaust gas out of the cylinder through the open exhaust valve during an exhaust stroke immediately following the power stroke. The exhaust valve may be closed before reaching top dead center of the exhaust stroke.
Various embodiments of the invention include operating an internal combustion engine without a compression stroke and using an external compressor to provide compressed air to a cylinder of the inter combustion engine instead of using a piston in the cylinder to compress the air. For example, a diesel piston engine configured to operate without a compression stroke may be coupled an external compressor. The external compressor may provide compressed air to the diesel engine at or above a spontaneous combustion or auto ignition temperature of a fuel. A cylinder of the diesel engine may receive the compressed air at top dead center and the fuel may be injected into a cylinder to mix with the compressed air and form a combustion product or combustion gas. The combustion gas may drive the piston to bottom dead center to complete a power stroke. After bottom dead center, exhaust gas may be pushed out of the cylinder by the piston as it returns to top dead center to complete an exhaust stroke. At top dead center, the cylinder may receive the next charge of compressed air from the compressor and an injection of fuel to initiate the next power stroke, and so on. Thus, a diesel engine may be operated in a two stroke mode. Likewise, a gasoline engine may be operated in a two stroke mode using an external compressor to provide air at or above a sustained combustion temperature but below a spontaneous combustion temperature and using a spark plug to initiate combustion.
The external compressor 110 is configured to receive air at ambient pressure and provide compressed air or gas to the cylinder 122. In some embodiments, a gas other than air may be compressed by the external compressor 110 and provided as a compressed gas to the cylinder 122. The compressor 110 is configured to compress the air to some pressure greater than ambient pressure, for example, 4, 8, 10, 12, 16, 17, 18, 20, 25, 30 or greater, times ambient pressure (e.g., atmospheres). The compressed air is also heated, e.g., adiabatically, to a substantial percentage of a combustion temperature during the compression. At about 8 times ambient pressure, the temperature of the compressed gas may be about the auto ignition temper of various fuels, e.g., diesel. Optionally, the external compressor 110 may heat the air to a temperature above the auto ignition for a fuel, a temperature below the auto ignition and above a combustion temperature for the fuel, or a temperature below the combustion temperature for the fuel.
The intake valve 132 may admit the compressed gas from the external compressor 110 to the cylinder 122 during a power stroke. The fuel injector 136 is configured to inject fuel into the cylinder 122 also during the power stroke. Alternatively, some other fuel source may provide fuel to the cylinder 122 during the power source. The injected fuel may mix with the compressed gas to form a combustion gas in the cylinder 122 and drive a piston 124 during the power stroke. An exhaust valve 134 may be opened and release exhaust gas from the cylinder 122 during an exhaust stroke. In some embodiments, fuel may be mixed with the compressed gas before introduction to the cylinder 122 and combustion may be initiated, e.g., using a spark or a glow plug.
The power stroke, when the internal combustion engine is rotating in a forward direction, includes a portion of the internal combustion engine cycle when the piston is after top dead center and before bottom dead center and is moving away from the cylinder head 126. The exhaust stroke, when the internal combustion engine is rotating in the forward direction, may be defined as a portion of the internal combustion engine cycle when the piston is after bottom dead center and before top dead center and is moving toward from the cylinder head 126.
Conversely, the power stroke, when the internal combustion engine is rotating in a reverse direction, is a portion of the internal combustion engine cycle when the piston is before top dead center and after bottom dead center and is moving away from the cylinder head 126. The exhaust stroke, when the internal combustion engine is rotating in the reverse direction, is a portion of the internal combustion engine cycle when the piston is before bottom dead center and after top dead center and is moving toward the cylinder head 126.
In
In
In
In
In
In some embodiments, the fuel 232 is mixed with the compressed gas 230 externally to the cylinder 122, instead of being injected using the fuel injector 136. The compressed gas 230 may be at a temperature below auto ignition and combustion may be initiated using a spark. Fuels for which this may be useful include gasoline, hydrogen, liquefied petroleum gas, liquefied natural gas, natural gas, ethanol, methanol, propanol, methane, propane, butane, paraffin, coal dust, saw dust, rice dust, flour, grain dust, cellulose dust, alcohol, a blend of gasoline and alcohol, natural gas, methane, propane, butane, liquefied natural gas, hydrogen, and/or the like. Additional fuels include cellulose products, forms of carbon, hydrocarbon, waste chemicals and materials (garbage, paint, hazardous waste, chemical waste, tires) biological products and materials. Compounds that release energy (exothermic reaction) whenever combined with another chemical (e.g., Oxygen) may be used as fuels. The fuels and compounds may be finely ground into particulates and/or dust. In some embodiments, particulates and/or dust may be mixed into a slurry or suspended in a combustible fluid.
An optional motor/generator 112 may be configured to drive the external compressor 110. In various embodiments, the external compressor 110 may be driven using electric motors, gasoline engines, diesel engines, turbines, wind generators, solar generators, fuel cells and/or the like. Energy for driving the external compressor 110 may be stored in batteries, the grid, flywheels, fuel cells, etc. The external compressor 110 may intake ambient air, compress the air and heat the compressed air (e.g., adiabatically) to a temperature at or above a spontaneous combustion temperature of the fuel. In some embodiments, a heater may be disposed in the compressor 110 or inline with the compressor and configured to heat the air. In various embodiments, the external compressor 110 includes root gear pumps, screw pumps, reciprocating compressors, rotary compressors, centrifugal compressors, axial compressors, mixed compressors, and radial flow compressors, and the combinations thereof. In some embodiments, the external compressor 110 is one stage of a multi stage compressor system configured to intake pre-compressed air.
Referring back to
A controller 150 may be coupled to valves and sensors via a control coupling 152. The controller 150 may be coupled to the intake valve 132 and the exhaust valve 134 and configured to control opening and closing of these valves. The controller 150 may be coupled to the fuel injector 136 and configured to control timing of the fuel injector 136. In some embodiments, the controller 150 is coupled to the compressor 110, the motor generator 112, and/or the combustion purifier 140. The controller 150 may control an output pressure of the compressor 110 and an RPM of the motor generator 112. The controller 150 may control a temperature in the combustion purifier 140.
The controller may be coupled to sensors 154, 156, 158 and/or 160. The sensor 154 includes one or more sensors configured to sense various parameters in the internal combustion engine 120 including a position of the piston 124, a velocity of the piston 124, rotations per minute (RPM) of the crankshaft 210, a pressure within the cylinder 122, a temperature within the cylinder 122, and/or the like. The sensor 156 includes one or more sensors configured to sense various parameters of the compressed gas 230 including a pressure, temperature, volume, flow, velocity, and/or the like. The sensor 158 includes one or more sensors configured to sense various parameters of the external compressor 110 including an RPM temperature, pressure, volume, flow, and/or the like. The sensor 160 includes one or more sensors configured to sense various parameters of the exhaust gas 238 and/or combustion purifier 140 including a pressure, temperature, volume, flow, velocity, and/or the like. While four sensors, namely sensor 154, 156, 158 and 160 are illustrated in
In various embodiments, the control coupling 152 includes a cam shaft and valve train, a wiring harness, relays, circuit boards, processors, optical transmission devices, optical cable, wireless transmitter, wireless receivers, electrical valve actuators, a hydraulic system, and/or the like. In various embodiments, the controller 150 includes a computer system, a memory, a processor, a computer interface, a cam shaft, a timing belt, a distributor, and/or a combination thereof. In some embodiments, the controller 150 includes a plurality of computer systems, processors, and/or interfaces. For example, a first processor in the controller 150 may be configured to control valves and injectors (e.g., valve 132, valve 134, and fuel injector 136) while a second processor in the controller 150 is configured to control the compressor 110 and a third processor is configured to receive data from sensors (e.g., sensors 154, 156, 158, and 160) and communicates the data to the first and/or second processor.
While one cylinder is illustrated in
In operation, a power produced by the internal combustion engine 120 during the power stroke may be adjusted by selecting a position of the piston 124 for closing the intake valve 132. A total energy of the power stroke depends on an amount of compressed gas 230 in the cylinder 122 available for burning the fuel 232 and an amount of fuel 232 mixed with the compressed gas. The amount of compressed gas 230 in the cylinder 122 in turn depends on the position of the piston 124 when the intake valve 132 closes. The longer after top dead center the intake valve 132 closes, the more compressed gas 230 is admitted to the cylinder 122 for burning with the fuel 232. An amount of fuel 232 may be selected using the fuel injector 136 for a desired fuel/air mixture of the compressed gas 230 and fuel 232. Thus, a constant fuel/air mixture may be maintained for any amount of compressed gas 230 in the cylinder. At a constant fuel/air mixture, the farther after top dead center the intake valve 132 closes the more power and the closer to top dead center the intake valve 132 is closed the less power. The fuel air mixture may be further optimized for each position of the piston 124 at which the intake valve is closed. In some embodiments, an amount of fuel 232 less than optimum may be injected into the cylinder for running the internal combustion engine 120 in a lean condition. Alternatively, an amount of fuel 232 greater than optimum may be injected into the cylinder for running the internal combustion engine 120 in a rich condition, e.g., for cooling the cylinder and piston.
While the internal combustion engine 120 may be operated above 40 RPM, it may also be operated below 40 RPM. For example, by selecting the timing of the intake valve 132 and exhaust valve 134 and an amount of fuel injected by the fuel injector 136, the internal combustion engine 120 may be operated over a range of RPM below 40 RPM without stalling the internal combustion engine 120. In various embodiments, the internal combustion engine 120 may be operated at or below 30, 20, 10, 5, 2, 1 RPM, or near zero RPM or even at zero RPM. By selecting a timing and sequence of the intake valve, the exhaust valve 134, and the fuel injector 136, the internal combustion engine 120 may be operated to rotate in a reverse direction. Thus, the internal combustion engine 120 may be operated through a continuous range of RPM from greater than 40 RPM to less than 40 RPM, and from 40 RPM down through zero RPM to a negative RPM or reverse rotation.
When the internal combustion engine 120 is running at a slow RPM or stopped, it may be reversed. It will be apparent to a person having ordinary skill in the art that a forward or reverse rotation of the internal combustion engine 120 depends only on a timing and sequence of opening and closing the intake valve 132, the exhaust valve 134 and the fuel injector 136. For example, when the piston 124 of cylinder 122 is at a position before top dead center, the intake valve 132 may be open to charge the cylinder with compressed gas 230 and the exhaust valve 134 may be closed. Upon charging the cylinder 122 with compressed gas 230, the intake valve 132 is closed and the fuel injector 136 injects fuel 232 into the cylinder 122. The resultant combustion gas 236 will drive the piston 124 toward bottom dead center while rotating the crankshaft 210 in a counter-clockwise (reverse) direction. At bottom dead center, the exhaust valve may be opened to release the exhaust gas 238 as the crankshaft continues rotating counter clockwise. As the piston 124 moves from bottom dead center to top dead center the exhaust gas 238 is pushed out by the piston 124. At top dead center the intake valve 132 may be opened and the exhaust valve 134 may be closed and the cycle repeated. (See for example,
It will be apparent to a person having ordinary skill in the art that an internal combustion engine 120 including multiple cylinders 122 may be started from a stop without a clutch. For example, a cylinder 122 in which any one of the pistons 124 is in a position after top dead center may be charged with compressed gas 230 and injected with fuel 232 to begin combustion resulting in rotation of the crankshaft 210 in a forward direction. Other cylinders 122 may in turn be charged with compressed gas 230 and injected with fuel 232 in an appropriate sequence and at an appropriate position to continue driving the forward rotation. Thus, a vehicle powered by the internal combustion engine 120 may be driven to a stop (e.g., at a signal light) by progressively reducing the RPM to zero and then restarted by selecting an appropriate cylinder 122 for combustion. Similarly, a cylinder 122 in which the piston 124 is in a position before top dead center may be selected and charged with compressed gas 230 and injected with fuel 232 to begin combustion resulting in rotation of the crankshaft 210 in a reverse direction. Other cylinders 122 may in turn be charged with compressed gas 230 and injected with fuel 232 in an appropriate sequence and at appropriate positions to continue driving the reverse rotation. Another example includes an internal combustion engine 120 having multiple cylinders 122 and configured to drive a propeller in a ship. The propeller may be operated at full speed in a forward direction, slowed to a stop, reversed, accelerated in a reverse direction and operated at full speed in a reverse using a selection of timing and sequence of the valves and injectors.
A pressure of the compressed gas 230 in the cylinder 122 upon intake may be referred to as intake pressure. A peak pressure of the combustion gas 236 may be referred to as combustion pressure. A pressure to which the exhaust gas 238 is vented may be referred to as exhaust pressure. In some embodiments, the exhaust pressure may be selected to be about the same as the intake pressure. For example, if the intake pressure is about 9 times ambient, and the combustion pressure is about 18 times ambient the exhaust valve 134 may be opened when the volume of the cylinder 122 is about two times what the volume of the cylinder was at the time the intake valve 132 was closed. Thus, (neglecting volume of the cylinder head 126 for simplicity), if the intake valve is closed at 60 degrees after top dead center, the exhaust valve may be opened at about 120 degrees after top dead center (or 60 degrees before top dead center). Similarly, if the intake valve is closed at 90 degrees after top dead center, the exhaust valve may be opened at about bottom dead center. Similar calculations may be performed for when the exhaust pressure is selected to be ambient. For example, when the intake pressure is about 8 times ambient and the combustion pressure is about 17 times ambient, (again neglecting the cylinder head volume), if the intake valve 132 is closed at about 28 degrees after top dead center, the exhaust valve may be opened at about bottom dead center. Similarly, if the intake valve 132 is closed at about 25 degrees after top dead center, the exhaust valve may be opened at about 126 degrees after top dead center or about 54 degrees before bottom dead center.
The turbine 810 is coupled to the external compressor 110 via a coupling 812. In various embodiments, the coupling 812 includes a drive shaft, a generator, a transmission, etc. A sensor 852 may be coupled to the turbine 810 and configured to provide data to the controller 150. The sensor 852 includes one or more sensors configured to sense various parameters of the turbine 810 including a pressure, temperature, volume, flow, RPM, torque, and/or the like. The controller 150 may be coupled to the sensor 852 via a control coupling 152 and configured to receive data from the sensor 852.
The reservoir 820 is configured to receive compressed gas 230 from the external compressor 110 and store the compressed gas. The reservoir 820 is further configured to provide a constant supply of the compressed gas 230 to the internal combustion engine 120 at a desired pressure and temperature. When the reservoir 820 is large compared to the total volume of the cylinder 122, the pressure of the compressed gas 230 may be relatively unaffected by pulsation of discontinuous charging of the cylinder 122. A sensor 822 may be coupled to the reservoir 820 and configured to provide data to the controller 150. The sensor 822 includes one or more sensors configured to sense various parameters of the reservoir 820 including a pressure, temperature, volume, flow, RPM, torque, and/or the like. In some embodiments, the reservoir 820 may be insulated to maintain the temperature of the reservoir 820. Further, a heater (not shown) may be disposed in or around the reservoir to heat the compressed gas 230 and/or to add heat or make-up heat, e.g., heat lost during storage.
Turbines 920 and 922 are arranged in a two stage configuration. Turbine 920 may receive exhaust gas 238 and extract energy from the exhaust gas 238 to drive the external compressor 910. Turbine 922 may receive the exhaust gas 238 at a reduced pressure from turbine 920 and extract additional energy from the exhaust gas 238. Turbine 920 is configured to drive external compressor 910 and turbine 922 is configured to drive external compressor 912 using couplings 812. Optional energy storage 928 may be coupled to the turbines 920 and 922. In various embodiments, the energy storage 928 includes generators and batteries, flywheels, etc.
The controller 150 may be coupled to the external compressors 910 and 912 and the turbines 920 and 922 via control coupling 152 and configured to control these devices as described elsewhere here. The controller 150 may be coupled to a sensor 914 and 916 via coupling 152. The sensors 914 and 916 each include one or more sensors configured to sense various parameters of the external compressor 910 and 912 respectively including an RPM temperature, pressure, volume, flow, and/or the like. Sensors 925 and 926 may be coupled to turbines 920 and 922 respectively and configured to provide data to the controller 150 via the control coupling 152. The sensor 924 and 926 include one or more sensors configured to sense various parameters of the turbine 920 and 922 respectively including a pressure, temperature, volume, flow, RPM, torque, and/or the like. While a two stage compressor system is illustrated in
The reservoir 960 is configured to receive hyper-compressed gas 964 from the internal combustion engine 120 and store the gas at a high temperature. For example, the intake valve 132 may admit compressed gas 230 into the cylinder 122 during the power stroke and close when the piston 124 is at bottom dead center. During the exhaust stroke, with both the intake valve 132 and the exhaust valve 134 closed, the piston 124 may further compress the compressed gas 230 to produce hyper-compressed gas 964. At top dead center the exhaust valve 134 may be opened to output the hyper-compressed gas 964 via a three-way valve 944 to the reservoir 960. A valve 942 may further be used as a one-way valve and/or for maintaining storage of the hyper-compressed gas 964 in the reservoir 960. The reservoir 960 may include insulation 962 configured to conserve heat. The reservoir 960 may further include a heater 966 disposed in or around the reservoir 960 to make up heat loss during storage or further increase the temperature of the stored gas.
The reservoir 960 may provide compressed gas 230 from the stored hyper-compressed gas 964 via three-way valve 938. Valve 936 may be used for pressure reduction. In some embodiments, hyper-compressed gas 964 stored in the reservoir 960 may be used for driving the turbine 920 and may be directed to the turbine 920 via the three way valve 944. In some embodiments, the hyper-compressed gas 964 may be directed from the internal combustion engine 120 via the exhaust valve 134 and the three way valve 944 to the turbine 920.
In some embodiments, the internal combustion engine 120 may be used as a brake by pumping braking energy into the reservoir 960 in the form of hyper-compressed gas 964. The pumped gas may serve to reduce the RPMs of the internal combustion engine 120. An amount of braking may be controlled using the intake valve 132 to control a volume of compressed gas 230 admitted to the cylinder 122 for each cycle of the internal combustion engine 120. The amount of braking may be further controlled using the exhaust valve 134 to control output pressure of the hyper-compressed gas 964 to the reservoir 960. Thus, braking may be exerted over a wide range. For example, compressed gas 230 at 8 times ambient may be admitted to the cylinder 122 when the piston 124 is at bottom dead center. The compressed gas 230 may be further compressed by a factor of 8 to produce hyper-compressed gas 964 at 64 times ambient. In another example, the compressed gas 230 may be admitted to half the volume of the cylinder by closing the intake valve 132 when the piston 124 is at 90 degrees before top dead center and released when the compression ration ratio reaches 2:1 to produce hyper-compressed gas 964 at 16 times ambient. Thus, the external compressor 910 and the compressed gas 230 may be used to multiply the braking power of the internal combustion engine 120 over a wide range. Moreover, the reservoir 960 may be used to conserve the braking energy instead of dumping compressed gas to ambient.
In step 1006, the compressed gas is provided to a cylinder of the internal combustion engine after a piston in the cylinder has passed top dead center during a power stroke. The compressed gas may also be provided to the cylinder before top dead center and as the piston passes top dead center. In step 1008 fuel is provided to the cylinder before the piston reaches bottom dead center during the power stroke. In some embodiments, fuel is injected into the cylinder after the compressed gas is provided. Alternatively, fuel is provided with the gas as a fuel/air mixture.
In step 1010 combustion gas is produced during the power stroke from the mixture of the fuel and compressed gas in the cylinder. Combustion may be initiated using a spark. Alternatively, combustion may occur spontaneously when the temperature of the compressed gas is equal to or greater than an auto ignition temperature of the gas. Thus, the fuel and compressed gas are provided to the cylinder and the combustion gas is produced during the same power stroke. In step 1012, the combustion gas drives the piston toward bottom dead center during the power stroke.
In step 1014, exhaust gas is released from the cylinder during the exhaust stroke that immediately follows the power stroke. That is, there is no intervening power stroke. A portion of the exhaust gas may also be released during a portion of the power stroke. Thus, the combustion gas may not drive the piston all the way to bottom dead center and the exhaust gas release may begin before reaching bottom dead center. In step 1016, compressed gas is provided to the cylinder during a power stroke immediately following the exhaust stroke. While a single cylinder is described for the process 1000, the internal combustion engine may include more than one cylinder and each cylinder may be out of phase with other cylinders. Although the process 1000 for operating an internal combustion engine is described as being comprised of various components, fewer or more components may comprise operating an internal combustion engine and still fall within the scope of various embodiments.
In step 1112 the piston is driven toward bottom using the combustion gas. In step 1114, the exhaust valve is opened. The exhaust valve may be opened before, at, or after reaching bottom dead center. In step 1116 exhaust gas is pushed out of the cylinder via the exhaust valve. The piston is used during an exhaust stroke to push the exhaust gas out of the piston. There is no intermediate intake stroke between the power stroke and the exhaust stroke. In step 1118, the exhaust valve is closed. The exhaust valve may be closed before or after opening the intake valve for the next power stroke.
In step 1120, the exhaust gas is vented at a pressure greater than the ambient. The timing for opening the exhaust valve in step 1114 may be selected for a pressure of the exhaust gas greater than the compressed gas. In step 1122, a turbine is driven using the vented exhaust gas. In step 1124, the turbine is used to drive a compressor. In step 1126, the compressor is used to compress ambient gas and produce the compressed gas.
Several embodiments are specifically illustrated and/or described herein. However, it will be appreciated that modifications and variations are covered by the above teachings and within the scope of the appended claims without departing from the spirit and intended scope thereof. For example, an intercooler may be disposed between the reservoir 960 and the internal combustion engine 120. For example, any combustible fuel may be used in an engine. For example, waste products may be powdered and used in an engine. For example, multiple controllers may be employed to control various aspects of an internal combustion engine including valves, actuators, sensors, etc. Various embodiments of the technology include logic stored on computer readable media (e.g., the controller 150), the logic configured to perform methods of the invention.
The embodiments discussed herein are illustrative of the present invention. As these embodiments of the present invention are described with reference to illustrations, various modifications or adaptations of the methods and/or specific structures described may become apparent to those skilled in the art. All such modifications, adaptations, or variations that rely upon the teachings of the present invention, and through which these teachings have advanced the art, are considered to be within the spirit and scope of the present invention. Hence, these descriptions and drawings should not be considered in a limiting sense, as it is understood that the present invention is in no way limited to only the embodiments illustrated.
