A. Field of the Invention
The Invention is an apparatus and method for removing carbon and preventing the buildup of carbon, such as carbon deposits on particulate filters of diesel engines. The Invention also applies to the removal of carbon and prevention of the build-up of carbon on the internal engine components of diesel and gasoline engines, including cylinders, pistons, piston rings, piston ring grooves and exhaust system.
B. Statement of the Related Art
Beginning in 2007, new diesel truck engines in the U.S. were required to utilize emission controls comprising a particulate filter followed by injection of urea and a catalytic converter. The particulate filter catches soot, which is largely carbon, from the diesel engine and prevents the soot from blinding the catalytic converter or entering the ambient air. The urea (CO(NH2)2) is converted to ammonia (NH3) above 125° F. The ammonia decomposes to hydrogen, which reacts in the catalytic converter with nitrogen oxides (NOx), a pollutant, chemically reducing the nitrogen oxides to nitrogen (N2) and water (H2O). The use of urea to control NOx requires that urea always be available and that the diesel truck always must carry a supply of urea.
As soot accumulates in the particulate filter, the pores of the filter become clogged and the pressure drop of the exhaust gases across the filter increases. When the pressure drop across the filter exceeds acceptable limits (about 2.5 inches of water), the on-board engine control system disables the vehicle so that the vehicle cannot be driven. The on-board control system then attempts to ‘regenerate’ the filter by injecting hot gasses resulting from combustion of fuel through the filter.
If the regeneration step is not successful in adequately reducing the pressure drop across the particulate filter, the filter must be serviced or replaced. The filter is serviced by blowing high-pressure air through the filter to dislodge the soot. The filter is then re-checked for pressure drop. If blowing air through the filter is not successful, the filter is heated in a kiln to oxidize some of the carbon, followed by re-application of the high-pressure air and re-testing of the pressure drop. If blowing out the soot and heating the filter are not successful in achieving an acceptable pressure drop, then the filter must be returned to the factory and replaced with a new filter.
Conventional regeneration, high-pressure air blowing and kiln-baking damages the structure of the particulate filter and shortens the life of its components. Conventional regeneration repeatedly heats the particulate filter to a very high temperature to incinerate the solid carbon contained within the filter. The resulting thermal stresses on the ceramic core and on the seals of the particulate filter plus the physical violence of high-pressure air blowing shorten the structural life of the filter.
Even if cleaning of the filter is successful, substantial carbon remains in the filter after cleaning and the useful life of the cleaned filter is uncertain. As a filter becomes more and more clogged, multiple service events may be required to deal with the clogged filter, with each service event providing only a temporary fix. Servicing and replacing the filter is a costly maintenance item for owners of diesel engines.
An additional issue with cleaning diesel engine particulate filters is that the ash resulting from regeneration of the filters is regulated as hazardous waste due to the metal content, which further increases the cost of cleaning the filters.
Carbon accumulates in other locations on a diesel or gasoline engine. For example, carbon from incompletely combusted fuel will accumulate on the piston and piston rings of a reciprocating engine. The build-up of the carbon over time interferes with the operation of the engine. The build-up of carbon around the piston rings of a reciprocating engine will result in reduced mobility of the piston rings, poor sealing between the rings and the cylinders, loss of compression with the resulting loss of power and efficiency, and increased blow-by of gases past the piston rings and into the crankcase, causing contamination and eventual failure of the engine lubricants. The current methods for removal of that carbon require disassembly of the engine and manual scraping of the carbon, which is expensive and time consuming.
Carbon also accumulates in the combustion chambers and exhaust flues of any apparatus that combusts a fuel, including furnaces, ovens and boilers. Manual removal of the carbon by scraping is a regular item of maintenance for combustion appliances.
Hydrogenation of solid coal to form liquid hydrocarbons is known for the production of oil and lubricants. See the Wikipedia article, “Coal Liquefaction” accessed Aug. 5, 2014. The known hydrogenation of coal is a process that occurs at elevated temperatures and pressures.
The Invention is an apparatus and method for the prevention of the build-up of carbon and for the removal of carbon, such as carbon soot trapped by a particulate filter of a diesel truck engine, carbon deposits on pistons and piston rings of an engine, or carbon deposits or build-up on any combustion apparatus. The apparatus and method of the invention involve hydrogenating the carbon by exposing the parts to be cleaned to hydrogen gas (H2). When elemental carbon (such as the carbon trapped in the diesel particulate filter or carbon deposits on piston rings) is exposed to hydrogen gas, the hydrogen reacts chemically with the carbon, converting the carbon to a variety of hydrocarbons, which may be in a liquid or gaseous state. In other words, exposure of the carbon to hydrogen converts the carbon to oil and to gaseous hydrocarbons. The resulting oil may then be removed manually as a liquid or by combusting the oil.
The first step is to obtain a source of hydrogen. While compressed elemental hydrogen gas may be used, oxyhydrogen, or HHO, also may supply the hydrogen. HHO is a stoichiometric mixture of hydrogen (H2) and oxygen (O2) generated by the dissociation of water through electrolysis. The HHO may be generated using the HHO generator described in U.S. Pat. No. 8,852,410, ‘Electrolytic hydrogen generator and method,’ issued Oct. 7, 2014 to Luke J. Turgeon et al. The electrical power supply for the HHO generator may be the reciprocating engine itself, and will utilize about one or two horsepower produced by the engine to generate the HHO. Any suitable source may act as the electrical power supply for the HHO generator, including electricity provided by the electric power industry.
Where the apparatus to be cleaned is a particulate filter from a diesel truck, the filter may be cleaned in place. The particulate filter is a component of the exhaust system of the diesel engine. For cleaning the particulate filter in place, HHO is introduced into the exhaust gas stream of the diesel engine on the intake side of the filter, as by injecting the HHO through a port, while the engine is running The temperature of the exhaust gas and of the particulate filter is below the ignition temperature of the HHO. As a result, the HHO does not ignite in the particulate filter and does incinerate the solid carbon. Instead, the HHO converts the carbon to liquid and gaseous hydrocarbons by hydrogenation. The oil and gaseous hydrocarbons then may be combusted in the catalytic converter.
Even though hydrogenation is exothermic, the process of hydrogenation of the solid carbon in the particulate filter to liquid or gaseous hydrocarbons is a cold process; namely, the temperature of the exhaust gas, the HHO and the particulate filter does not increase significantly during the reaction. As a result, the ceramic core, seals and other components of the particulate filter are not subject to the thermal stresses or physical violence of conventional regeneration, avoiding damage to the structure of the particulate filter and extending the service life of the filter.
For cleaning a particulate filter that has been removed from the exhaust system of the diesel engine, air is blown through the filter and the HHO is introduced into the air stream prior to the filter. The HHO converts the carbon soot to oil and gaseous hydrocarbons, which are drained or washed from the filter or combusted in the catalytic converter when the filter is re-installed in the exhaust system.
Where the apparatus to be cleaned comprises the internal parts of a reciprocating engine, such as the pistons and rings of a diesel or gasoline engine, HHO is introduced on the intake side of the engine while the engine is running If the engine is turbocharged, the HHO may be introduced either before or after the turbocharger compressor.
Conventional turbocharger compressors generally are constructed of aluminum, which is subject to embrittlement by exposure to hydrogen gas. As a result, injection of the HHO after the turbocharger compressor is preferable to avoid damage to the compressor. The HHO must be injected at a suitably high pressure to overcome the pressure created by the turbocharger compressor. The HHO generator of U.S. Pat. No. 8,852,410, incorporated by reference, may supply HHO of 100 psi, substantially more than the pressure produced by a turbocharger compressor, and has proven suitable in practice.
When HHO is introduced to the intake of the running engine, the HHO enters the combustion chamber on the intake stroke at a relatively low temperature and is compressed along with the fuel and air mixture to an increased temperature and pressure. The increased temperature and pressure of the hydrogen in the cylinder prior to ignition promotes the reaction of the hydrogen with the carbon deposits on the pistons and rings, turning the carbon deposits to oil and to gaseous hydrocarbons, which then are consumed by the engine or blown past the rings into the crankcase. Introduction of HHO into the intake of the engine may be sufficient to clean carbon from the particulate filter in the exhaust system as well.
Introduction of the HHO into the intake of the engine also serves to reduce particulate emissions from the engine by providing more complete combustion of the fuel and controls NOx emissions from the engine by providing hydrogen to reduce the NOx to N2 and H2O, which the inventors have confirmed experimentally, as discussed below.
The Invention can be used for the subtractive shaping of carbon, such as the shaping of carbon electrodes. A jet of H2 or HHO may be used for the reductive shaping of a carbon work piece to any desired physical shape without physically touching the carbon work piece with a solid tool (such as a cutter of a milling machine or lathe) or liquid tool (such as a water jet) and without generating heat. The carbon may be shaped to any desired shape, including shapes too delicate to be achieved by use of a solid or liquid cutting tool.
A similar injection of H2 or HHO serves to remove carbon deposits from any location, such as the inside of a stove, furnace or boiler.
Because the HHO generator may be mounted to the truck and may move with the truck, the HHO generator may provide HHO constantly whenever power is provided to the HHO generator, as when the diesel engine is operating. HHO may be injected continuously into the diesel engine exhaust gas upstream from the particulate filter to continuously clean solid carbon from the particulate filter to avoid accumulation of particulate matter in the filter. Continuously cleaning the solid carbon from the filter prevents an increase in the pressure drop across the filter and prevents efficiency losses in the diesel engine due to increased backpressure on the engine exhaust ports. Continuous injection of the HHO into the exhaust gas stream either upstream or downstream of the particulate filter allows continuous reaction between the hydrogen in the HHO and the NOx in the exhaust gas to reduce NOx to N2 and H2O. The inventor believes that continuous injection of HHO into the exhaust gas will allow elimination of urea injection for diesel trucks.
Alternatively, injection of HHO may be selectable between different locations in the exhaust system of the diesel engine and the intake to the engine and may be episodic or periodic. In this instance, HHO may be directed to the particulate filter if the particulate filter needs cleaning, to the exhaust gas downstream of the particulate filter to control NOx or to the intake side of the diesel engine to clean carbon from the engine internal components or to improve combustion efficiency, all as determined by the user or under the control of a control system. The direction of HHO to the components to be cleaned may be on a pre-determined schedule.
As another alternative, HHO may be injected to a plurality of locations on the diesel engine intake and exhaust system simultaneously, for example, to the intake of the engine after the turbocharger compressor to increase combustion efficiency and to prevent carbon deposits, to the upstream side of the particulate filter to prevent carbon deposits, and to the downstream side of the particulate filter to reduce NOx to N2 and H2O. The amount of HHO sent to each location may be appropriately metered to accomplish each task.
The example engine 2 is illustrated as being equipped with a turbocharger compressor 16, but the invention also applies to non-turbocharged engines 2 and to supercharged engines 2. Intake air 18 on a low-pressure side of the turbocharger compressor 16 at an intake 17 of the diesel engine 2 is compressed by turbocharger compressor 16 and conveyed from the high-pressure side 20 of the turbocharger compressor 16 into the engine 2. The intake air 18 is further compressed within a cylinder 21 of the engine 2 to a pressure and temperature above the spontaneous combustion point for droplets of the liquid fuel. The liquid fuel (e.g. diesel fuel) is injected at high pressure in a fine mist of droplets into the cylinder. The outside surfaces of the droplets begin spontaneously combusting and burn from the outside inward, since only the outside surface is exposed to oxygen, with combustion continuing in an onion-peel fashion.
Exhaust gas 22 is discharged from exhaust port 23 and travels through an exhaust system 24. Exhaust system 24 may include a particulate filter 26, urea injection duct 28 and a catalytic converter 30. Exhaust system 24 also may include a conventional turbocharger impeller 40 (
The HHO 12 is discharged from the HHO generator 10 upstream of an object to be cleaned of solid carbon. The object to be cleaned may be an exhaust system component to be cleaned 25.
The HHO 12 may be discharged through the particulate filter 26 substantially continuously when the engine 2 is running to keep the particulate filter 26 clear of solid carbon. Alternately, HHO 12 may be discharged through the particulate filter 26 periodically or as needed to remove solid carbon from the particulate filter 26.
The exhaust gas 22, the HHO 12 and the exhaust system component to be cleaned 25 are maintained below the ignition temperature of the HHO 12 when HHO 12 is discharged to the exhaust system component to be cleaned 25 so that the HHO 12 does not combust in the exhaust system component to be cleaned 25. If the HHO 12 combusts, the hydrogen in the HHO 12 is no longer available for hydrogenation of the solid carbon and the HHO 12 is ineffective for cleaning solid carbon.
The inventors believe that a diesel engine 2 equipped with HHO 12 injection into the exhaust system 24 upstream of the particulate filter 26 will be able to maintain the particulate filter 26 in a compliant condition and will not require regeneration or service by soot blowing, heating in a kiln, or replacement of the particulate filter 26.
The second location for HHO 12 injection is through a turbocharger low-pressure side injection duct 36 to the low-pressure side of the turbocharger 16. The third location for HHO 12 injection is through a turbocharger high-pressure injection duct 38 into the turbocharger duct 20 on the high-pressure side of the turbocharger 16. For both of the second and third locations, the HHO 12 enters the cylinders of the engine 2 along with the intake air 18. The HHO 12 is compressed and heated within the cylinder 21 of the diesel engine 2 and exposed to solid carbon that has accumulated within the cylinder 21 and on and around the piston rings and on the interior of the engine 2. The heated, high-pressure hydrogen gas in the HHO 12 reacts with the solid carbon, hydrogenating the solid carbon and converting the solid carbon to hydrocarbon oil and gaseous hydrocarbons, which are combusted in the cylinder 21 or blown past the piston rings into the crankcase. The engine 2 is thus cleaned of solid carbon deposits and oil and gaseous hydrocarbons serve to provide fuel for the engine 2.
An engine 2 may be equipped for HHO 12 injection at any or all of the locations shown by
Where the discharge of HHO 12 is to the exhaust system 24 or to the high-pressure side 20 of the turbocharger compressor 16, the HHO generator 10 will supply HHO 12 at a pressure sufficient to overcome the maximum pressure of the intake air 18 or the exhaust gas 22 at those locations.
The injection of HHO 12 derived from water has advantages over the injection of urea for the control of NOx. Because water contains more hydrogen than urea per unit mass and volume, a truck equipped with a diesel engine, HHO generation and injection of HHO for NOx control can go farther on one gallon of water than an otherwise identical truck with urea injection for NOx control can go on one gallon of urea solution.
If HHO 12 is injected in the exhaust system 24 upstream of the particulate filter 26 (
Injection of HHO on the high-pressure side 20 of the turbocharger compressor 16 as shown by
The method of
The HHO 12 injection options of
From
For the method of
Using the apparatus of
The following numbered elements are illustrated by the drawings and discussed in the detailed description of an embodiment.
This application is entitled to priority from U.S. Provisional Application 62/036,193 filed Aug. 12, 2014 by Luke J. Turgeon and entitled “apparatus and method for preventing and removing carbon deposits,” which is incorporated by reference as if set forth in full herein. The following document also is incorporated by reference as if set forth in full herein: U.S. Pat. No. 8,852,410, entitled ‘Electrolytic hydrogen generator and method,’ issued Oct. 7, 2014 to Luke J. Turgeon et al.
Number | Date | Country | |
---|---|---|---|
62036193 | Aug 2014 | US |