Patent Publication Number: US-2010115721-A1

Title: Engine cleaning system and method for cleaning carbon deposits in engines

Description:
TECHNICAL FIELD 
     This disclosure relates generally to an apparatus and a method for cleaning carbon deposits that accumulate on various surfaces in an internal combustion engine. 
     BACKGROUND 
     A typical internal combustion engine includes a plurality of combustion chambers or cylinders, each accommodating a reciprocating piston. The pistons typically include a pair of compression rings to prevent the escape of gases from the cylinder around the sides of the piston during the compression stroke of the piston. The pistons also typically include an oil control ring to preclude oil from entering the combustion chamber. 
     One problem associated with all internal combustion engines is the accumulation of carbon deposits on various piston surfaces, such as on the top lands and in the compression ring and oil control ring grooves. The carbon deposits become very hard over time and, unless removed regularly, will lead to increased oil consumption and the seal between the piston and cylinder liner become compromised. Further, the long term presence of carbon deposits will cause the cylinder liner or bore to be polished or worn, which leads to increased oil consumption and may require the liner to be replaced. As these carbon deposits build up sufficiently over time, engine performance degrades and the failure rate of the engine increases. 
     Various engine conditioning procedures and systems have been devised for removing the carbon deposits from internal combustion engines. One known engine conditioning procedure involves disassembly and/or overhaul of an engine and individual cleaning and/or replacement of some engine parts. These engine cleaning and overhaul procedures are complex, time consuming, costly, and require the services of a skilled mechanic. Nevertheless, the disassembly and overhaul procedures permit a direct inspection of the engine parts and thereby enable an accurate visual determination of the cleanliness and condition of the inspected parts. If the disassembly procedure is employed, new pistons, rings and liners are typically installed. 
     Known carbon cleaning agents for use on disassembled engine components include ULTRA ONE™ (sodium metasilicate, surfactants, water), GOODWRENCH® TOP ENGINE CLEANER (2-butoxyethanol, naphtha, 4-methyl-2-pentanol, 9-octadecendic acid) and PRO SERIES SIMPLE GREEN® MAX AUTOMOTIVE CLEANER &amp; DEGREASER (2-butoxyethanol, water). Other engine cleaning agents include acetone, benzyl alcohol, propylene glycol, ethylene glycol, polyol esters, n-methylpyrrolidone, ethoxylated nonylphenols and others. Steam cleaning and cleaning with dry ice (CO 2 ) are also known. 
     Even though disassembly/overhauling is the only known method for cleaning combustion chambers that is 100% effective at removing carbon deposits or replacing damaged parts, liquid cleaners and additives are routinely used to clean combustion chambers to avoid the downtime and costs associated with the disassembly of the engine. One such method involves manually or mechanically injecting an alcohol based cleaner into the combustion chamber after removing the spark plug. This method is obviously inapplicable to diesel engines. Further, alcohol based products tend to cause the carbon deposits to break off as particles rather than dissolve in the cleaning solvent. When carbon deposit particles break off, they can become trapped between the piston rings, causing engine problems and increased oil consumption. 
     Other less complicated procedures involve the use of a carbon cleaning agent in the form of a fuel additive and/or oil additive without disassembly of the engine. These procedures do not permit a determination of the effectiveness of the carbon cleaning operation or an inspection of the parts. Thus, while fuel or oil additives for cleaning carbon deposits are known, such fuel or oil additives take a long time to work, can be difficult to evaluate, and are often ineffective. Known fuel additives include napthenic petroleum distillates, aliphatic naphthas, polyolefin amines, propoxylated alcohols, and light aromatic petroleum distillates in various combinations as well as other materials that are sold under a variety of trade names. Known oil additives include proprietary detergents and diluent oils and are also sold under a variety of trade names. 
     Some procedures go to great lengths to avoid disassembly and/or overhaul of the engine. For example, one five-step procedure that employs five different hydrocarbon-based liquids including: a fuel additive; an oil crankcase additive; an aerosol air intake cleaner; an air induction cleaner; and a piston/ring cleaner added through the spark plug openings. 
     Another problem associated with all of the above techniques for removing carbon deposits from internal combustion engines is the reliance upon hydrocarbon-based materials such as alcohols, surfactants and solvents, all of which can leave deposits in the form of residues on the piston surfaces. Further, penetration into the top compression ring grooves remains problematic as both polar and non-polar hydrocarbon-based solvents are ineffective in removing or dislodging carbon deposits from compression ring grooves. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect of this disclosure, a piston cleaning apparatus, a method for cleaning carbon deposits from an internal combustion engine and an improved internal combustion engine manifold are disclosed that enable pistons to be cleaned with water, such as deionized water, for improved results over the techniques taught in the prior art, and without disassembling or overhauling the engine. 
     In another aspect of this disclosure, a piston cleaning apparatus is disclosed for an internal combustion engine having at least one cylinder that accommodates a piston that is susceptible to accumulating carbon deposits as discussed above. The piston cleaning apparatus comprises a manifold having at least one water inlet and an internal passageway network. The manifold may be an air intake manifold, an exhaust manifold or combination of the two. The internal passageway network provides fluid communication between at least one water inlet and the cylinder. The piston cleaning apparatus also comprises a water source in communication with the water inlet. The water source may optionally be in communication with a pressure source for delivering water to the manifold and the cylinder. 
     In yet another aspect of this disclosure, a method for cleaning carbon deposits in an internal combustion engine is disclosed that comprises: operating the engine at a first speed; delivering water to the at least one water inlet for a first time period and at a first flow rate while operating the engine at the first speed; and increasing the engine speed to a second higher speed for a second time period. Water delivery to the cylinders may be stopped during the time period when the engine is operated at the second higher speed. 
     In another aspect, a manifold for an internal combustion engine is disclosed that is connectable to a pressurized water source for delivering water to a cylinder of the engine while the engine is running. The manifold comprises an internal passageway network passageway providing fluid communication to the cylinder of the engine, and at least one water inlet in communication with the internal passageway network of the manifold and the cylinder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial schematic illustration of an internal combustion engine equipped with a piston cleaning apparatus and a modified manifold in accordance with this disclosure; 
         FIG. 1A  is a partial and enlarged view of the piston and cylinder shown in  FIG. 1 , particularly illustrating the lands and grooves of the piston that are susceptible to carbon deposit accumulation; 
         FIG. 2  is another partial schematic illustration of an internal combustion engine and modified manifold for delivering water to the combustion chambers in accordance with one aspect of this disclosure; and 
         FIG. 3  is another partial schematic illustration of an internal combustion engine and modified manifold for delivering water to the combustion chambers in accordance with another aspect of this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     An internal combustion engine  100  that includes at least one combustion chamber  102  associated with a piston  104  is shown in  FIGS. 1 and 1A . The piston  102  may include a pair of compression rings  106 ,  108  and an oil control ring  109 . The compression rings  106 ,  108  serve to prevent the escape of gases from the chamber  102  around the sides of the piston  104  and out of the cylinder  110  during the compression stroke of the piston  104 . The oil control ring  109  inhibits oil from leaking upward past the oil control ring  109  and compression rings  106 ,  108  and towards the exhaust passageway  122  as shown in  FIG. 1 .  FIG. 1A  particularly illustrates the surfaces of the piston  104  that tend to accumulate carbon deposits during normal use such as the top land  112  disposed above the compression ring  106 , the second land  113  disposed between the compression rings  106 ,  108 , the third land  115  disposed between the compression ring  108  and oil control ring  109 , as well as the compression ring grooves  114 ,  117  and the oil control ring groove  119 . 
     While this disclosure is directed primarily at the removal of carbon deposits that accumulate on the surfaces illustrated in  FIG. 1A ,  FIG. 1  also shows a rocker arm  116 , crankshaft  118 , air intake passageway  120 , the exhaust passageway  122 , and intake and exhaust valve members  124 ,  126  respectively. Fuel is provided through a fuel injection line  128  which is combined with compressed air flowing through the line  130  in the fuel/air injection nozzle  132  before the mixture of fuel and air is delivered to the combustion chamber  102 . 
     During the operation of an internal combustion engine, deposits of carbon and similar materials form on the various surfaces of the engine pistons, including the top land  112 , second and third lands  113 ,  115 , compression ring grooves  114 ,  117  and oil control ring groove  119  as shown in  FIG. 1A . Unless removed regularly, these carbon deposits can build up sufficiently to degrade engine performance, increase the failure rate of an engine and substantially increase oil consumption. 
     Therefore,  FIG. 1  also illustrates the use of a cleaning apparatus  134  that delivers water to a combustion chamber  102 . The cleaning apparatus  134  includes a water source or tank  136  that may be pressurized, such as by a compressed air source shown schematically at  138 , which can conveniently be the “shop air” that is readily available in vehicle or truck maintenance facilities. A pump (not shown) may also be employed as a pressure source, or the water source  136  may be elevated to provide water flow  137  ( FIG. 1A ) to the engine  100 . Other means for generating flow from the water source  136  to the engine  100  or the manifold  140  will be apparent to those skilled in the art. As noted above, deionized water will not leave a residue on the surfaces of the piston  104 , the interior surface of the cylinder  110  or other engine surfaces exposed to the deionized water. However, the use of deionized water is not required. 
     As illustrated in  FIG. 1 , the water source  136  may be linked to either an air intake passageway  120  of the manifold  140  or an exhaust passageway  122  of the manifold  140 . In the structure illustrated in  FIG. 1 , the manifold  140  includes both the air intake passageway  120  and the exhaust passageway  122 . For a multiple cylinder engine, the manifold  140  may include a network of air intake passageways  120  for delivering air to the combustion chambers  102  and a network of exhaust passageways  122  for exhausting air from the combustion chambers  102 . 
     The water source or reservoir  136  may be in the form of a tank, such as a tank or vessel that may be pressurized with a compressed air source  138 , be equipped with a pump or some other means (not shown), or gravity may be exploited to deliver the water to the manifold  140 . The water source  136  may be connected to a flow regulator  142  which may be a controllable valve. Also, a flow meter  144  may be employed which can be used to calculate or keep track of the amount of water delivered to the manifold  140  and the combustion chambers  102 . 
     As shown in the schematic illustrations of  FIGS. 1-2 , the water source  136  may be linked to the manifold  140  by a single conduit  146  (although it may be interrupted by the flow regulator  142  and flow meter  144 ). Referring to  FIG. 1 , the conduit  146  may be connected to a water inlet  148  that provides communication between the water source  136  and the air intake passageway  120  or a water inlet  150  that provides communication between the water source  136  and the exhaust passageway  122 . Use of the air intake passageway  120  of the manifold  140  may be effectively employed because the water may be delivered to the combustion chambers  102  while the engine is running at the low speed and therefore less pressure may be required to deliver water to the combustion chambers  102  when the air intake passageway  120  is utilized versus the exhaust passageway  122 . However, use of the exhaust passageway  122  is also clearly feasible and within the scope of this disclosure. 
     The water inlets  148 ,  150  may be simple fittings mounted to an exterior of the manifold  140  as illustrated in  FIG. 1 . The water inlets  148 ,  150  may also be an integral part of the manifold  140  structure as illustrated in  FIG. 2 . The water may be delivered to the intake or exhaust passageways  120 ,  122  directly through the inlets  148 ,  150 . Further, as illustrated in  FIGS. 2-3 , a conduit network may be disposed within the manifold  140  to facilitate the delivery of water to the combustion chambers  102 . Still referring to  FIG. 1 , the water inlets  148 ,  150  may be connected to conduits  152 ,  154  disposed within the air intake passageway  120  or exhaust passageway  122 . While the use of the internal conduits  152 ,  154  provide a more reliable and even distribution of water to the combustion chambers  102  of a multiple-cylinder engine, the internal conduits  152 ,  154  are not necessary and the passageways or passageway networks  120 ,  122  of the manifold  140  may be used without the additional conduits shown at  152 ,  154  in  FIG. 1 . 
     Turning to  FIG. 2 , the water inlet  148  as shown may be connected to a plurality of conduits  152 ′,  152 ″ in parallel. Specifically, the conduit  146  passing through the water inlet  148  may be connected to the six conduits  152 ′,  152 ″ leading to the cylinders  110  using a T-connection shown in phantom at  156  in  FIG. 2 . Alternatively, the conduit  146  and water inlet  148  may be connected to a branch conduit such as the one shown at  158  in  FIG. 2  that provides parallel communication to three conduits  152 ′ shown at the left in  FIG. 2  and three conduits  152 ″ shown at the right in  FIG. 2 . While the reference numeral  148  is used for the water inlet of  FIG. 2  indicating that the water inlet  148  is connected to the air intake passageway  120  of the manifold  140 , it will be noted that the design of  FIG. 2  is equally applicable to use of a water inlet  150  connected to an exhaust passageway  122  of the manifold  140  as illustrated in  FIG. 1 . In short, this disclosure is intended to encompass the use of both the air intake passageways  120  as well as the exhaust passageways  122  of a manifold  140  for communicating water to the combustion chambers  102 . 
     Another embodiment is illustrated in  FIG. 3 . The flow meter  144  splits the water flowing through the conduit  146  into two flow paths illustrated by the conduits  160 ,  162 . The conduit  162  provides communication to the conduits  152 ″ shown at the right in  FIG. 3  and the conduit  160  provides communication to the conduit  164  which provides communication to the conduits  152 ′ shown at the left in  FIG. 3 . A block  166  is shown that separates the conduits  162 ,  164 . As an alternative, the branch conduit  160  may be eliminated and the conduits  162 ,  164  connected (eliminating the block  166 ) to provide parallel communication between all six conduits  152 ′,  152 ″ and the water source  136 . The conduits  152 ′,  152 ″ pass through the manifold  140  through the plurality of water inlets shown generally at  148 . Again, while  FIG. 3  is directed toward delivering water to the air intake passageway  120  of the manifold  140 , the design of  FIG. 3  is also equally applicable to delivery of water through the exhaust passageway  122  of the manifold  140  as illustrated schematically in  FIG. 1 . 
     The employment of the internal conduits  152 ,  152 ′,  152 ″ and  154  as illustrated in  FIGS. 1-3  insures equal distribution of the deionized water to the individual cylinders  110 . Equal distribution of the water is advantageous to provide uniform cleaning of the cylinders  110  and pistons  104 . Also, equal water distribution prevents excess water from being delivered to one cylinder and/or too little water delivered to another cylinder, both of which could result in reduced carbon deposit removal. The conduits  146 ,  152 ,  152 ′,  152 ″,  154 ,  160 ,  164  may be fabricated from flexible or pliable materials. Conduits that are disposed exterior to the manifold  140  such as the conduits  146 ,  160 ,  164  may be fabricated from a suitable plastic material. The conduits that extend inside the manifold  140 , such as the conduits  152 ,  152 ′,  152 ″,  154  should be fabricated from a suitable heat-resistant and pliable material such as copper or aluminum tubing. The water inlets  148 ,  150  may be standard fittings, such as those equipped with a check valve. 
     After extensive research and testing, applicants have surprisingly found that operating the engine at a low speed (and under a low load) while delivering water into the combustion chambers  102  when the piston surfaces and the exhaust gases are at a lower temperature, e.g., less than about 100° C., enables the warm liquid water to penetrate the “pores,” cracks or fissures of the carbon deposits that have accumulated on the piston surfaces. This penetration can occur within a shorter time period, which can range from about 2 to about 8 minutes. As used herein, the term “about” when used to modify a numerical value means plus or minus ten percent (±10%) of the stated value. For at least some six cylinder diesel engines, a suitable low engine speed for the water delivery phase can range from about 400 to about 1200 rpm. The flow rate of water delivered during the first water delivery phase may be controlled so that a cumulative amount of water delivered to the cylinders is less than about 5% of the sump oil volume, with ranges of less than 4% and less than 3% being particularly effective. For example, if the vehicle includes 10 gallons (37.85 liters) of sump oil, and the time period for the water delivery phase is 5 minutes, an appropriate water flow rate may be about 1100 grams or milliliters of water per minute or less. 
     After the liquid water has penetrated the structures of the carbon deposits at the lower temperature, the engine speed may be increased thereby increasing the temperature of the pistons and exhaust gases to greater than 100° C., thereby vaporizing the water or turning it into steam. The steam expands within the pores, cracks and/or fissures of the carbon deposits, thereby breaking the deposit structures and causing the broken-off pieces of carbon deposits to flow out of the combustion chamber through the exhaust stream. After the engine speed has been increased, the water delivery may be stopped or at least substantially reduced. Stopping the water delivery altogether during the second higher engine speed phase can help ensure a fast or even violent vaporization of the water that has penetrated the carbon deposit structures, thereby encouraging damage and breakage of the carbon deposit structures and the removal of the broken off carbon deposit through the exhaust stream. Further, the second phase can be longer than the first phase; the second phase can range from about 5 to about 25 minutes. The higher engine speeds used during the second phase to increase the temperature of the pistons and the exhaust gases can range from about 1200 to about 2400 rpm for at least some six cylinder diesel engines. The two phases may be sequentially repeated for an extensive time period ranging up to four or more hours. 
     The disclosed apparatuses and methods may be automated. For example, any one or more of the flow regulator  142 , flow meter  144 , compressed air source  138 , fluid level sensor in the water source  136  tank (not shown), pressure sensor in water source  136  tank (not shown), engine throttle (not shown), and exhaust gas temperature sensor (not shown) may be linked to a controller or computer for controlling the duration of the two phases (low speed-low temperature-water delivery; high speed-high temperature), the water flow, the engine speed and for monitoring the exhaust gas temperatures during the first and second phases. However, one of the advantages of the disclosed methods and apparatuses is the simplicity and ease in which the disclosed methods and apparatuses can be used. Hence, a sophisticated and automated control system is not necessary and a high level of skill is not required to either carry out the disclosed methods manually or to use the disclosed apparatuses manually. 
     INDUSTRIAL APPLICABILITY 
     Instead of cleaning agents that rely upon alcohol, organic solvents or surfactants that can leave the residue on the piston and/or cylinder, the disclosed methods and apparatus use water as the cleaning agent/solvent. To avoid leaving mineral residues on the engine components, the water may be deionized water. After extensive research, it has been surprisingly found that the use of deionized water while operating the engine at a low speed, and therefore a low temperature below the boiling point of water (&lt;100° C.), provides an environment conducive to the heated liquid water penetrating carbon deposits on the upper land surfaces of the piston as well as carbon deposits disposed in the compression seal ring and oil control ring grooves of the piston. After an appropriate time period of delivering water into the combustion chambers while the engine is running at a low speed, the pores, cracks or fissures of the carbon deposits have been substantially penetrated by the heated liquid water. Then, the engine speed may be increased thereby increasing the temperature in the combustion chamber and the water that has permeated the carbon deposits. Without being bound to any particular theory, as the temperature of the engine increases while it is operated at a higher speed, the water is vaporized or turned into steam thereby causing the water to expand within the carbon deposits and causing the carbon deposits to crack and break off from the surfaces of the piston and removed through the exhaust stream. 
     It has been surprisingly found that the combination of water and the operation of the engine at two different speeds and therefore two different temperatures provides an improved mechanism for removing carbon deposits that is less expensive and more efficient than techniques that rely upon the use of expensive hydrocarbon-based solvents. Deionized water may be particularly effective because it will not leave any mineral residue on the engine components. However, the use of deionized water is not required. 
     Generally, water may be delivered into the cylinder ports (either intake or exhaust) while operating the engine at a low speed, and at a low load for a time ranging from about 2 to about 8 minutes, although a range of from about 3 to about 7 minutes may be employed, and in one example, a time period of about 5 minutes for at least some six cylinder diesel engines has been found to be particularly effective. The engine exhaust temperature during this first phase or first time period may be less than the boiling point of water (&lt;100° C.). It will be apparent to those skilled in the art that modifying the engine speed and time period for the water delivery may be necessary to optimize the exhaust temperature close to but below 100° C. to enhance the water penetration into the carbon deposits. For a six cylinder diesel engine, the engine speed during the delivery of the water can range from about 400 to about 1200 rpm, although a range of from about 600 to about 1000 rpm will be applicable to many six cylinder diesel engines. For example, useful first engine speeds of about 700 and about 800 rpm have been found to be effective. 
     After the initial water delivery, the water delivery may be stopped and the engine speed may be increased to increase the temperature of the pistons. The time period for the second phase where the engine is operated at a higher speed but under a low load condition can range from about 5 to about 25 minutes, with a range of from about 10 to about 20 minutes being particularly effective. For example, a time period of about 15 minutes has been found to provide good results for at least one six cylinder diesel engine. The increased engine speed during this second time period can range from about 1200 to about 2400 rpm. Alternatively, a range of from about 1600 to about 2000 rpm may be used. For some six cylinder diesel engines, a useful higher-speed is about 1800 rpm. 
     During the second higher speed phase, the water flow  137  shown in  FIG. 1A  will most likely not reach the top land  112 , second and third lands  113 ,  115  and compression seal and oil control ring grooves  114 ,  117 ,  119  of the piston  104  but will most likely pass out through the exhaust passageway  122  ( FIG. 1 ). The second high speed phase generates heat, thereby enabling the water to quickly evaporate and increase the speed at which hard carbon deposit layers to break off. Thus, the second high speed phase provides a mechanical cleaning action and the water flow may not be needed. Operating both the first water delivery phase and second high speed phase under a low load avoids the use of dynamometers. 
     The amount of water delivered to the cylinders may also be controlled. It has been found that a cumulative amount of water delivered to the engine cylinders during the first, low engine speed time period should be less than about 5% of the total volume of sump oil, with ranges of less than about 4% and less than about 3% being particularly effective. For example, if the vehicle includes 10 gallons (37.85 liters) of sump oil, and the time period for the water delivery is 5 minutes, the water flow rate may be about 1100 grams or milliliters of water per minute or less to limit the water delivered during the first phase to slightly under about 3% of the sump oil volume. Of course, larger engines may utilize larger amounts or volumes of water, with some large diesel engines using up to about 3000 grams or milliliters of water per minute. 
     The engine load for the low speed water delivery phase will be dependent upon the particular engine being treated, but for a six cylinder diesel truck engine, the load during the water delivery can range from about 30 Nm to about 80 Nm, with a load of about 57 Nm for at least some six cylinder diesel engines being particularly effective. The load on the engine for the higher-speed water-free phase can range from about 200 Nm to about 300 Nm, with a load of about 254 Nm for at least some six cylinder diesel engines being particularly effective. The procedure can be repeated for as long as eight hours, depending upon the severity of the carbon deposits and the condition of the engine. 
     The disclosed methods and apparatuses can be used in any engine, such as four, six, eight and twelve cylinder engines, and engines of any configuration such as 1-engines or straight engines, V-engines, etc. The disclosed methods and cleaning apparatuses  134  may also be used on a vehicle during normal operation and maybe permanently mounted to the vehicle as original equipment or as a retrofit. That is, the water source  136  and cleaning apparatus  134  may be disposed on the vehicle and connected to the manifold  140 . If necessary, a pump (not shown) could be used in place of the compressed air source  138 . 
     One disclosed cleaning method comprises operating the engine at a low speed, under a low load and at a low temperature while delivering deionized water through the intake valves or through the exhaust valves of the engine cylinders while the engine is running at the low speed/low load/low temperature. During the delivery of the deionized water, the speed of the engine, the flow rate of water, and the duration or time period of the delivery of the deionized water may all be controlled. For example, the engine speed can range from about 400 to about 1200 rpm, the water delivery time period can range from about 2 to about 8 minutes and the water flow rate can be limited to less than about 5% of the volume of sump oil over the time interval. The low engine speed helps to maintain a low exhaust temperature that may be below the boiling point of water (100° C.). The water delivery may then stopped and the engine speed increased to anywhere from greater than about 1200 rpm to about 2400 rpm, with no water flow or a reduced water flow and for a longer time period ranging from about 10 to about 25 minutes. 
     The disclosed methods may be used to maintain and prolong the life of both diesel and gasoline internal combustion engines. Specifically, the disclosed methods may be easily carried out in a typical maintenance facility. Deionized water sources  136  in the form of suitable tanks are readily available. The water sources  136  can be equipped with a pump or may be connected to a compressed air source  138  that is typically used in vehicle maintenance facilities for inflating tires and operating air powered tools. To practice one disclosed embodiment, the maintenance facility needs only to purchase a simple valve or flow controller  142 , a flow meter  144  and the necessary conduits or tubing to connect the water source  136  to an engine manifold  140 . 
     The engine manifold  140  can be modified for purposes of carrying the disclosed method or for accommodating the connection to the disclosed cleaning apparatus  134 . Existing manifolds  140  can be readily retrofitted with one or more water inlets  148 ,  150  for connection to the water source  136 . Further, as the value of the disclosed maintenance technique becomes apparent to those skilled in the art of engine maintenance, manifolds  140  readily equipped to be connected to a pressurized water source may be provided without substantially redesigning current engine manifolds. Many manifolds already include an inlet for the introduction of cleaning solvents for the cylinders. Applicants have surprisingly found that deionized water or water in general is a superior solvent choice, particularly when used with the methods disclosed above. 
     The disclosed engine cleaning methods and apparatuses are estimated to cost about 10% of the costs associated with an engine overhaul that includes the replacement of the pistons, rings and liners. The disclosed cleaning methods and apparatuses are also estimated to cost substantially less than any carbon deposit cleaning program that relies upon fuel and/or oil additives.