Cleaning and liquid contact with solids – Processes – Oils – grease – tar – or wax removal – by dissolving
Reexamination Certificate
2002-11-06
2003-09-09
Delcotto, Gregory (Department: 1751)
Cleaning and liquid contact with solids
Processes
Oils, grease, tar, or wax removal, by dissolving
C134S039000, C134S042000, C510S187000, C510S421000, C510S499000, C510S505000, C510S506000
Reexamination Certificate
active
06616776
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
This invention relates to a cleaning composition for removing carbonaceous deposits and to methods for removing engine deposits in a reciprocating internal combustion engine. More particularly, this invention relates to a method for removing engine deposits in a reciprocating internal combustion engine which comprises introducing a two part cleaning composition into an air-intake manifold of the engine and running the engine while the cleaning composition is being introduced.
2. Description of the Related Art
It is well known that reciprocating internal combustion engines tend to form carbonaceous deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports and intake valves, due to the oxidation and polymerization of hydrocarbon fuel, exhaust gas recirculation (EGR), positive crankcase ventilation (PCV) gases. It is believed that some of the unburnt hydrocarbons in the fuel undergoes complex cracking, polymerization and oxidation reactions, leading to reactive moieties which can interact with the fuel, recirculated gases and lubricating oils; thus forming insolubles in the combustion chamber and combustion pathways. These deposits, even when present in relatively minor amounts, often cause noticeable operational performance issues such as driveability problems including stalling and poor acceleration, loss of engine performance, increased fuel consumption and increased production of exhaust pollutants.
Fuel based detergents and other additive packages have been developed, primarily in gasoline fuels to prevent the formation of unwanted deposits. As a consequence, problems in fuel delivery systems, including injector deposit problems, have been significantly reduced. However, even after employing these detergent additives injectors and other components require occasional additional cleaning to maintain optimum performance. The present additives are not completely successful eliminating deposits, especially for removing preexisting heavy deposits or deposits upstream of the fuel entry. Often these preexisting and upstream deposits require complete engine tear down. Attempts have been made to use higher concentrations of detergents and additives in the fuel. However since these detergents are mixed with the fuel they are generally employed at concentrations less than 1% primarily for compatibility with elastomers, seals, hoses and other components in the fuel system. Moreover, for these detergent additives in the fuel to remove deposits from the various parts of an engine, they needed to come into contact with the parts that require cleaning.
Specific engine configurations have more pronounced problematic deposit areas due to the intake systems. For example, throttle body style fuel injector systems where the fuel is sprayed at the initial point of air flow into the system allows the intake to remain reasonably clean using the fuel additive, however port fuel injection spark ignition (PFI SI) engines spray the fuel directly into the air stream just before the intake valves and direct injection spark ignition (DISI) engines spray the fuel directly into the combustion chamber. As a result, upstream components from the fuel entry on the intake manifold of PFI SI and DISI engines are subject to increased formation of unwanted deposits from oil from the positive crankcase ventilation (PCV) system and exhaust gas recirculation (EGR). These upstream engine air flow components can remain with engine deposits even though a detergent is used in the fuel. Even with the use of detergents, some engine components when present, such as intake valves, fuel injector nozzles, idle air bypass valves, throttle plates, EGR valves, PCV systems, combustion chambers, oxygen sensors, etc., require additional cleaning.
New engine technologies designed to deliver maximum fuel efficiency, are more susceptible to deposit build up. In particular, engines such as direct injection spark ignition as well as modern diesel engines using high exhaust gas recirculation ratios to achieve lower NO
x
, form significant intake system deposits and since fuel delivery takes place inside the combustion chamber, these engines do not benefit from fuel based deposit control additives for intake system deposit removal.
Recently, direct injection spark ignition (DISI) engines have been introduced as an alternative to conventional port fuel injection spark ignition (PFI SI) engines. In the past few years, at least three types of DISI engines (from Mitsubishi, Toyota, and Nissan) have been commercially introduced into the Japanese market, and some models are now available in Europe and selected markets in Asia. Interest in these engines stems from benefits in the area of fuel efficiency and exhaust emissions. The direct injection strategy for spark ignition engines has allowed manufacturers to significantly decrease engine fuel consumption, while at the same time maintaining engine performance characteristics and levels of gaseous emissions. The fuel/air mixture in such engines is often lean and stratified (as opposed to stoichiometric and homogeneous in convention PFI SI engines), thus resulting in improved fuel economy.
Although there are many differences between the two engine technologies, the fundamental difference remains fuel induction strategy. In a traditional PFI SI engine, fuel is injected inside the intake ports, coming in direct contact with the intake valves, while in DISI engines fuel is directly introduced inside the combustion chamber. Recent studies have shown that DISI engines are prone to deposit build up and in most cases, these deposits are hard to remove using conventional deposit control fuel additives. Given that the DISI engine technology is relatively new, there is concern that with accumulated use, performance and fuel economy benefits may diminish as deposits form on various surfaces of these engines. Therefore, the development of effective fuel detergents or “deposit control” additives and methods to deliver these cleaning solutions to the intake systems, thus preventing or reducing such deposits in DISI engines is of considerable importance.
In addition, advances have been made in diesel engines such as the use of low sulfur fuels, use of exhaust gas recirculation (EGR) and other engine treatment systems have tended to form more tenacious and difficult to remove deposits, while at the same time requiring higher levels of engine cleanliness for operation of these systems. The EGR and PCV gases as well as blow back gases during valve overlap contribute to intake system deposit formation. These deposits can not be removed from fuel-based deposit control additives. As a result, a different method of deposit removal is required in these engine technologies. DISI engines and gaseous fueled engines (e.g., natural gas engines) also require a similar deposit removal technique. Furthermore, increased reliance on alternative fuels such as hydrogen, natural gas and other hydrocarbon based fuels has also lead to the need for new compositions for cleaning the resulting carbonaceous deposits due to the combustion of these fuels.
Accordingly, disclosed herein is a method for removing engine deposits in reciprocating engines which does not require complete disassembly of the engine and suitable for different engine types. This method can be used in gasoline, diesel, and natural gas internal combustion engines by introducing a novel cleaning composition comprising a first and second solution, into the air intake manifold of a warmed up and operating internal combustion engine, thereby removing carbonaceous deposits.
SUMMARY OF THE INVENTION
The present invention provides a method for administering a cleaning composition to remove carbonaceous deposits in a reciprocating internal combustion engine. More particularly, this invention relates to a method for removing engine deposits in a reciprocating internal combustion engine which comprises introducing a cleaning composition into an air-intake manifold of a
Ahmadi Majid R.
Vaudrin Damon C.
Caroli Claude J.
Chevron Oronite Company LLC
Delcotto Gregory
Foley Joseph P.
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