WO2016120723A2

WO2016120723A2 - System and method for controlled compression ignition reactions

Info

Publication number: WO2016120723A2
Application number: PCT/IB2016/000111
Authority: WO
Inventors: Stephen Holloway; Peter Richard MARTIN; Andrew Smith
Original assignee: Radical Combustion Limited
Priority date: 2015-01-29
Filing date: 2016-01-29
Publication date: 2016-08-04
Also published as: WO2016120723A3

Abstract

In at least one aspect of this disclosure, a method of controlling compression ignition in a compression ignition (CI) combustion system can include introducing a combustion primer (CP) and oxygen into a cylinder of the CI combustion system before and/or during a compression cycle, introducing a pilot charge of primary fuel reactant (PFR) into the cylinder before and/or during the compression cycle, allowing the pilot charge of PFR to combust at and/or before top dead center (TDC) of the cylinder to form combusted PFR (C-PFR), and combining a main charge of PFR with the CP, the C-PFR, and the oxygen to cause the main charge of PFR to instantaneously and/or homogeneously burn upon introduction into the cylinder due to the generation of radicals by the CP and C-PFR.

Description

SYSTEM AND METHOD FOR CONTROLLED COMPRESSION IGNITION

REACTIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Serial No. 62/109,107, filed 29 January 2015 and entitled: System and Method for Controlled Compression Ignition Reactions, which is incorporated herein by reference in its entirety.

Field of the Invention

[0001] The present disclosure relates to combustion cycles, more specifically to compression ignition systems.

Background

[0002] Combustion engines are used in countless vehicles and powered devices. Fuel is becoming ever more expensive and pollution is being ever more controlled. For at least these reasons, it is clear that the demand will only increase for combustion engines that perform with maximum efficiency and minimal pollution.

[0003] Compression Ignition (CI) engines are of high interest because of their higher working efficiency as compared to spark ignition (SI) or gasoline engines.

[0004] Homogeneous charge compression ignition (HCCI) systems, which seek to modify the combustion chemistry in order to achieve a more complete combustion reaction, can increase efficiency and reduce pollutants. However, at present, there are no sufficient systems or methods for starting and/or sustaining HCCI.

[0005] Typically, in HCCI systems, a fraction of the exhaust gases or combustion products from the previous combustion cycle are fed back or retained in the cylinder in order to modulate the combustion reaction and consume residual reactants. Secondary fuels have been employed that have different reactivities as compared to the primary fuel reactant (PFR) to modulate the combustion recation and consume residual reactants. HCCI engines that operate predomintantly on this fuel mixing principle are termed reactively controlled. Conventional wisdom in the art is to base the amount of secondary fuel used on the volume of primary fuel used in the system. [0006] For CI engines there are two known types of systems (known as dual fuel systems) which utilize a secondary fuel to achieve fuel savings (i.e., replacement and enhancement). For replacement systems some percentage of the primary fuel is replaced by a secondary fuel. Typically this is in the range 15% to 80% of secondary fuel used. In practice the efficiency of the engine when operated on a plurality of fuels at these levels is lower than when operated on the primary fuel alone.

[0007] Enhancement systems use a much lower percentage of secondary fuel to act as an accelerant (rate) and/or to enhance the consumption of fuel to improve the combustion of the primary fuel (typically less than about 15%). Therefore, the secondary fuel (which may be a lower or higher cost than the primary fuel by volume) acts as an ignition improver or combustion enhancer or both. The combustion improvement is attributed to a number of factors, which include but is not limited to: faster burn, reduced engine knock, advanced ignition timing, more homogenous combustion, more even cylinder pressure profile and faster progression of the flame front.

[0008] One of the difficulties in maximizing mechanical energy that is reliably and uniformly delivered to the crankshaft of a CI engine is that using typical diesel fuel, the combustion event ignition delay (onset), is both relatively long in terms of time and can be variable. It is therefore difficult to predict and accurately control, on a per firing cycle basis, when and where (in terms of crankshaft rotational position in terms of degrees) fuel ignition will occur.

[0009] There is a danger that if the fuel is injected too early combustion will begin before top dead center (TDC) resulting in reduced efficiency as the combustion process is not then synchronised with the pump characteristics of the engine. Similarly, if fuel injection occurs too late in the cycle of the engine, peak pressure and temperature are not achieved in the cylinder (due to an increase in volume produced by movement of the piston) and neither is maximum torque because the crankshaft has rotated away significantly from TDC position. At the extreme, incomplete and inefficient combustion of the fuel is the overall result.

[00010] In practice, for CI engines using diesel fuel, precise synchronisation required for maximum efficiency mechanical output delivered consistently to the crankshaft is difficult to achieve, maintain, and control. Moreover, the conventional control loop technique of using feedback to stabilise and therefore partially optimise the engine power output is of limited use due to the rapidly changing combustion process (timing and completeness) and the fact that it is by definition always based on the result of previous combustion cycles.

[00011] Thus, owing to concerns over fuel/energy supplies, and the environmental impact of engine emissions, there is a significant need for engines that provide high efficiencies while meeting or exceeding current emission standards. However, to achieve all of the benefits of changed combustion chemistry, to maximise those benefits, and to ensure that they occur throughout the full range of engine operation requires a control strategy and control system that is based on the underlying chemical processes, which are part of the overall combustion process not just the engine operation.

Summary

[00012] Presently described are compression ignition engine system(s) and methods in which the stoichiometric ratios and/or timing of introduction of the primary fuel reactant (PFR), oxygen reactant (OxR) and combustion primer (CP) are tightly controlled such that engine efficiency is maximized across all operational states (rpms and loads) of the CI engine while using less CP.

[00013] In at least one aspect of this disclosure, a method of controlling compression ignition in a compression igination (CI) combustion system can include introducing a combustion primer (CP) and oxygen into a cylinder of the CI combustion system before and/or during a compression cycle, introducing a pilot charge of primary fuel reactant (PFR) into the cylinder before and/or during the compression cycle, allowing the pilot charge of PFR to combust at and/or before top dead center (TDC) of the cylinder to form combusted PFR (C-PFR), and combining a main charge of PFR with the CP, the p-PFR, and the oxygen to cause the main charge of PFR to instatnaeously and/or homogenously burn upon inctroduction into the cylinder due to the generation of radicals by the CP and p-PFR.

[00014] Introducing the pilot charge of PFR can include introducing the pilot charge of

PFR with the CP and the oxygen. Introducing the pilot charge of PFR can include introducing the pilot charge of PFR after the CP and the oxygen. In certain embodinments, introducing the pilot charge of PFR can include introducing the pilot charge of PFR a plurality of times for a given compression cycle. [00015] Combining the PFR includes at least one of; injecting the PFR in the intake air, fumigation, or direct injection of the PFR into the cylinder. The CP can include by way of non- limiting example, an oil, for example, as a transport medium that undergoes pyrolysis to form light hydrocarbons (C1-C8), a C1-C8 hydrocarbon, liquefied petroleum gas (LPG), tertiary butyl hydroperoxide, Nitrous Oxide, or any other suitable CP or a combination thereof.

[00016] Combining the main charge of PFR includes introducing the PFR into the cylinder at about TDC. Allowing the pilot charge of PFR to combust can include allowing the pilot charge of PFR to fully combust at or before TDC.

[00017] The method can further include controlling the introduction and/or combination of at least one of the the CP, pilot charge of PFR, main charge of PFR, or the oxygen using an open loop controller using predetermined data. Controlling the introduction can include controlling an amount of the CP, the oxygen, and/or the PFR that is introduced into the cylinder. The method can further include switching to a closed loop feedback controller if one or more conditions are exceeded based on at least one sensor.

[00018] In at least one aspect of this disclosure, a combustion system can include a reciprocating engine having at least one cylinder and an air intake for providing intake oxygen (0₂) to the at least one cylinder, a fuel introduction system comprising fuel injectors for a primary fuel reactant (PFR) and a combustion primer (CP) a control system including a memory having computer readable instructions stored thereon for controlling compression ignition in a compression igination (CI) combustion system, the instructions comprising one or more steps of a method as described herein.

[00019] In another aspect, a non-transitory computer readable medium can include a list of computer executable instruction for controlling compression ignition in a compression igination (CI) combustion system, the list of instructions comprising one or more steps of a method as described herein.

[00020] The preceding general areas of utility are given by way of example only and are not intended to be limiting on the scope of the present disclosure and appended claims. Additional objects and advantages associated with the compositions, methods, and processes of the present invention will be appreciated by one of ordinary skill in the art in light of the instant claims, description, drawings, and examples. For example, the various aspects and embodiments of the invention may be utilized in numerous combinations, all of which are expressly contemplated by the present description. These additional advantages, objects and embodiments are expressly included within the scope of the present invention. The publications and other materials used herein to illuminate the background of the invention, and in particular cases, to provide additional details respecting the practice, are incorporated by reference.

Brief Description of the Drawings

[00021] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating an embodiment of the invention and are not to be construed as limiting the invention. Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying figures showing illustrative embodiments of the invention, in which:

[00022] Fig. 1 is a schematic view of a combustion system in accordance with this disclosure, shown at the end of the intake stage;

[00023] Fig. 2 is a schematic view of portions of the combustion system of Fig. 1, shown at the end of or during the compression stage;

[00024] Fig. 3 is a schematic view of portions of the combustion system of Fig. 1, shown at the main charge of PFR introduction/ignition stage;

[00025] Fig. 4 is a schematic view of portions of the combustion system of Fig. 1, shown during instantaneous and/or homogeneous combustion and expansion of the reactants; and

[00026] Fig. 5 is a schematic view of portions of the combustion system of Fig. 1, shown at the exhaust stage.

[00027] Fig. 6 illustrates the fuel vs. mass air per cylinder. Experiments are performed at

1400 rpm constant speed with varying throttle (0% EGR, 6° before TDC pilot injection).

Detailed Description

[00028] The following is a detailed description provided to aid those skilled in the art in practicing the present invention. Those of ordinary skill in the art may make modifications and variations in the embodiments described herein without departing from the spirit or scope of the present disclosure. All publications, patent applications, patents, figures and other references mentioned herein are expressly incorporated by reference in their entirety.

[00029] The present description provides systems and methods that improve the fuel efficiency and the emissions of a compression ignition (CI) or spark ignition engine or both by modifying the combustion chemistry and/or the timing of introduction or reactants thereof. The herein described methods result in increased combustion efficiency, mechanical efficiency, and thermodynamic efficiency, which results in enhanced engine performance and consequent fuel savings.

[00030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description is for describing particular embodiments only and is not intended to be limiting of the invention.

[00031] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise (such as in the case of a group containing a number of carbon atoms in which case each carbon atom number falling within the range is provided), between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either both of those included limits are also included in the invention.

[00032] The following terms are used to describe the present invention. In instances where a term is not specifically defined herein, that term is given an art-recognized meaning by those of ordinary skill applying that term in context to its use in describing the present invention.

[00033] The articles "a" and "an" as used herein and in the appended claims are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article unless the context clearly indicates otherwise. By way of example, "an element" means one element or more than one element.

[00034] The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and/or B", when used in conjunction with open-ended language such as "comprising" can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[00035] As used herein in the specification and in the claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when separating items in a list, "or" or "and/or" shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as "only one of or "exactly one of," or, when used in the claims, "consisting of," will refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein shall only be interpreted as indicating exclusive alternatives (i.e., "one or the other but not both") when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of."

[00036] In the claims, as well as in the specification above, all transitional phrases such as

"comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of and "consisting essentially of shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

[00037] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from anyone or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a nonlimiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently "at least one of A and/or B") can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[00038] It should also be understood that, in certain methods described herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited unless the context indicates otherwise.

[00039] The following description, which illustrates and exemplifies certain aspects and embodiments of the systems and methods described herein, includes reference to the drawings, wherein like reference numerals identify similar structural features or aspects of the subject disclosure.

[00040] With reference to Fig. 1, in at least one aspect of this disclosure, a combustion system 100 includes a reciprocating engine having at least one cylinder 101. The system 100 further includes a piston 103 in operable communication with the cylinder 101 and configured to sealingly move within the cylinder cavity 107. The cylinder 101 is selectively in fluid communication with an air intake system 108 and a fuel introduction system including a primary fuel reactant (PFR) 112 and a combustion primer (CP) 110. The cylinder cavity 107 is in fluid communication with the atmosphere via an air intake 108a as well as an exhaust manifold 105 such that air with oxygen (0₂) can be drawn into the cavity 107 through the air intake 108a and exhaust gas can be exhausted through the exhaust manifold 105 into the atmosphere.

[00041] The system 100 also includes a control system 115 having a memory including computer readable instructions stored thereon for introducing (e.g., injecting) the various reactants, primers, or other combustion components at specific timings relative to the position of the piston 103, the instructions including one or more steps of an embodiment of the method as disclosed herein.

[00042] In certain embodiments, the control system 115 can also be connected to a flow sensor 117 configured to determine flow rate and/or oxygen content of air being drawn into the cylinder 101. In some embodiments, the control system 115 can also be connected to an exhaust sensor 119 configured to sense one or more characteristics (e.g., chemical content, NOx content, unburned reactants) of exhaust gas.

[00043] The control system 115 can control any suitable portion of the fuel introduction system (e.g., timing of the air valve 109, the CP valve 111, and/or the PFR valve 113 such as to control the flow rate of air/oxygen, CP, or PFR into the cavity 107). In some embodiments, the control system 115 can determine oxygen content of intake air (e.g., by using readings from sensor 117) and modify the input of CP and PFR to create a stoichiometric mixture to ensure approximately full usage of each reactant.

[00044] In certain embodiments, the CP can include an oil or oil distillate (e.g., petroleum or pyrolysis oil based), liquefied petroleum gas (LPG), Nitrous Oxide, or any other suitable fuel or additive. In certain embodiments, the CP includes by way of non-limiting example, an oil, for example, as a transport medium that undergoes pyrolysis to form light hydrocarbons (C1-C8), a C1-C8 hydrocarbon, liquefied petroleum gas (LPG), tertiary butyl hydroperoxide, Nitrous Oxide, or any other suitable CP or a combination thereof. Nitrous Oxide structurally is a C, H radical inducer or promoter such that the CP hydrocarbon in characteristics, capable of "scissoring" via homolytic fission into C, H radicals under conditions of elevated temperature and pressure and can be combusted and therefore consumed within the overall combustion process. Generally, the CP can be defined as not acting as a catalyst as it is either consumed or altered by the combustion reaction.

[00045] The CP can be selected to generate free radicals through homolytic fission when subjected to conditions of elevated temperature and pressure when outside its flammability range in air. The CP concentration with respect to air (Oxygen), can be controlled such that it is constantly present either below the Lower Flammability Limit (LFL) or above the Upper Flammability Limit (UFL) such that conventional combustion does not occur. The required concentration of the CP in air is low, allowing homolytic fission to take place generating a concentration of "primed" elevated energy free radicals to be formed but not combusted in the engine combustion chamber.

[00046] In further embodiments, the PFR can include at least one of diesel fuel, biodiesel, ethanol, gasoline, butane, isooctane, ethyltoluene, MTBE, kerosene, LPG, propane, coal tar, naptha, propane and combinations thereof. The CP and 0₂ mixture can be selected to generate radicals when subject to a compression cycle. The radicals can cause ignition of the PFR upon introduction of the PFR into the cylinder 101.

[00047] The CP and 0₂ mixture can be selected to generate an enhanced combustion environment when subject to a compression cycle. In certain embodiments, a pilot charge of PFR can be introduced into the cylinder 101 with the CP and 0₂ before and/or during the compression stage. The pilot charge of PFR can be be injected at the proper time and/or in the proper quantity to partially or fully combust, burn, or otherwise react to create additional radicals before the introduction of a main charge of PFR. This environment is condusive to the rapid, even and complete combustion of the PFR upon ignition.

[00048] Referring to Figs. 1-6, in at least one aspect of this disclosure, a method of controlling compression ignition in a compression igination (CI) combustion system can include introducing a combustion primer (CP) and oxygen into a cylinder 101 before and/or during a compression cycle, introducing a pilot charge of primary fuel reactant (p-PFR) into the cylinder before and/or at top dead center (TDC) of the cylinder, wherein the p-PFR and CP mixture radicalize or combust and form high energy reactive radicals (this 'stasis' highly reactive primed combustion state is a transient 'state of matter', sometimes referred to herein as a "pre- combustion state" of matter), and combining a main charge of PFR with the energized CP/p-PFR primer radicals, and the oxygen to cause the main charge of PFR to instantaneously and/or homogenously combust or burn upon introduction into the cylinder due to the generation of radicals by the CP and p-PFR.

[00049] The method can include determining an amount of intake oxygen (0₂) flowing into a cylinder 101 of an engine from an intake 108a during an intake stage of the cylinder. The method also includes calculating an amount of p-PFR, main charge PFR, 0₂, and/or a combustion primer (CP) to be injected into the cylinder 101 to achieve a stoichiometric oxygen- to-fuel ratio. Achieving any other suitable ratio of PFR, CP, and/or air is contemplated herein.

[00050] The method can include introducing the CP into the cylinder 101 before or during a compression stage (e.g., as shown in Fig. 1) of the cylinder 101 such that the CP and the 0₂ create a compressed mixture after the compression stage (e.g., as shown in Fig. 2). In some embodiments, introducing the CP can include using engine oil as the transport medium. Introducing the CP can include introducing a small additive quantity of CP such that the CP can be considered an additive instead of a fuel. Typically, additives which are added to the fuel tank have a concentration ratio of 0.1% by volume. The composition of the diesel fuel can comprise up to 7% addition of bio-diesel (FAME) by volume according to EN590:2009 standard. Both figures refer to the direct dilution of the PFR. For a system as described where the CP and PFR may be delivered via different methods the dilution occurs in the engine cylinder.

[00051] While the CP system 110 is shown as independent of the air system 108, it is contemplated that the CP can be combined in the air intake 108a with the air before entering the cylinder 101. Any other suitable configuration for mixing the CP and the 0₂ before or during compression is contemplated herein.

[00052] The pilot charge of PFR can be introduced before and/or during the compression cycle (shown in Fig. 1) to allow the pilot charge of PFR to react with the CP and the 0₂. In this regard, radicals can be created by compressing the CP and the 0₂ mixture, which can be enhanced with a small amount of pilot charge of PFR (shown in Fig. 2). Introducing the pilot charge of PFR can include introducing the pilot charge of PFR with the CP and the oxygen.

[00053] The pilot or multi-pilot of PFR appears important in raising the energy level.

However, the conditions that promote rapid combustion are only observed with a CP, and are not seen in diesel only pilot operation.

[00054] In a preferred embodiment, the p-PFR occurs prior to TDC. In additional preferred embodiments, the main PFR occurs at or before TDC so that main combustion occurs as close to TDC as possible.

[00055] In certain embodiments, introducing the pilot charge of PFR can include introducing the pilot charge of PFR after the CP and the oxygen. In certain embodinments, introducing the pilot charge of PFR can include introducing the pilot charge of PFR a plurality of times for a given compression cycle at any suitable time relative to the introduction of the CP.

[00056] The method can also include combining the main charge of PFR with the compressed mixture (e.g., as shown in Fig. 3). The radicals created by the burning of the pilot charge of PFR in this compressed mixture allows for the main charge of the PFR to quickly (e.g., instaneously) and/or homogeneously combust upon introduction into the cylinder 101 (as shown in Fig. 4). This reduces and/or eliminates traditional combustion lag of traditional CI systems which greatly enhances the efficiency of the engine with respect to fuel consumption and power generation. [00057] The PFR and the CP in the compressed mixture can be chemically selected and metered to homogenously burn upon ignition. Combining the PFR with the compressed mixture of CP and 0₂ can include at least one of injecting the PFR in the intake air, fumigation, or direct injection of the PFR into the cylinder. Any other suitable method is contemplated herein.

[00058] In certain embodiments, as shown in Fig. 5, the products of combustion can be purged during the exhaust cycle. It is contemplated that the reactants and amounts thereof can be selected such that there are approximately no residual reactants present in the cylinder for a subsequent compression and combustion reaction.

[00059] The method can further include determining an amount of a product of combustion (e.g., using sensor 119) in an exhaust gas and modifying the timing and/or amount of at least one of 0₂ intake 108, CP 110, PFR 112 or a combination thereof in response thereto to minimize pollution and increase efficiency. This can also be used in a situation where exhaust gas is redirected back into the intake such that a new formulation of CP and PFR can be used to account for the changing intake air chemistry.

[00060] Fig. 6 is a graph of fuel consumption versus the mass air per cylinder. The horizontal scale is the air flow. The orange line represents the fuel consumption on diesel only, while the blue line represents the fuel consumption when using the CP (in this example, LPG) with a pilot charge (p-PFR) of diesel fuel. The experiments are performed under constant conditions of 1400 rpm with varying throttle (0% EGR, 6° before TDC pilot injection). By closing off the throttle under fixed conditions fuel consumption can be measured against the amount of air available. As the air flow is reduced the standard diesel engine (which normally runs with excess air) hits the smoke limit and the fuel is combusted inefficiently (basically step change to a default value).

[00061] Therefore, Fig. 6 demonstrates the primer enhanced gas combustion as described herein. When using a pilot charge, better fuel economy is obtained with less oxygen, which produces lower exhaust particulates. Using small amounts of oxygen blended with gas expands the operating range of the engine. In other words, when using a CP much less air is required to burn the diesel, and the smoke limit is not reached until the air flow is severely reduced. This provides evidence of a stochiometric burn or complete homogeneous combustion when using a CP. [00062] In certain embodiments, when the engine is first started, and speed of the engine is above a certain RPM (e.g., 400 RPM), the system can be controlled by the control system 115 in an open loop mode. In such an open loop mode, the controller 115 will ignore the signal from the 0₂ sensor and calculate the air/fuel ratio based on inputs from the coolant and/or mass air flow (MAS) sensors, but mostly using a pre-programmed table stored in the memory of the controller. The table can include any suitable predetermined data.

[00063] The CP can be introduced and intimately mixed with the air flow by the controller or be introduced directly into the cylinder. A pilot charge of PFR is then injected in the presence of the CP and oxygen. Combustion of the pilot charge can begin immediately with compression because now the LFL of this mixture is exceeded. Combustion stops when the pilot charge PFR concentration is depleted below the LFL level. This primed non combusting mixture may be considered as an activated pre-combustion state of matter. The radicals thus generated are preserved during the remainder of the compression cycle. Then, the main charge of PFR can be injected into the engine combustion chamber (cylinder), where combustion occurs rapidly. Typical diesel PFR has a lower LFL than the primer. The overall combustion is now rapid in onset because of the presence of an atmosphere of activated free radicals into which the PFR is injected.

[00064] The combustion of the main charge of PFR can occur at or near top dead center

(TDC), i.e., the transition point between compression and expansion, to maximize efficiency. While the controller 115 is operated in an open loop scenario, a slow time (relatively) diagnostic overview signal can be taken by the controller 115 to ensure optimal engine operation as a fail safe. The system will stay in the open loop mode until the 02 sensor has varying voltage output (showing that it is hot enough to operate properly), a coolant sensor is above a specified temperature e.g., (about 40 degrees C), a specific amount of time has elapsed after starting the engine, and/or until any other suitable condition occurs.

[00065] Without being bound by any particular theory, it appears that timing of the combustion not when the PFR is injected is the result effective variable. If the ignition delay can be made low and consistent then the optimimum position for combustion of the main PFR can be achieved.

[00066] The specific values for the above conditions vary with different engines and are stored in the memory of the controller. When these conditions are met, the system goes into a closed loop operation. In the closed loop mode, the controller will calculate the air/fuel ratio and/or timing of injection based on the various sensors (e.g., based mainly on the 0₂ sensor). This can be used to maintain a suitable air/fuel ratio (e.g., about 14.7: 1).

[00067] The methods and/or portions thereof described herein can be stored on any suitable non-transitory computer readable medium in the form of any suitable computer executable code such that the controller 115 can execute the code thereon. It is also contemplated that the methods and/or portions thereof can be executed using analog circuitry in any suitable manner.

[00068] The methods and systems of the present disclosure, as described above and shown in the drawings provide for improved combustion engine systems with superior properties including increased efficiency and reduced pollution. While preferred embodiments of the systems and methods have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit and scope of the present disclosure. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the disclosure.

[00069] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. Such equivalents are intended to be encompassed by the following claims. It is understood that the detailed examples and embodiments described herein are given by way of example for illustrative purposes only, and are in no way considered to be limiting to the invention. Various modifications or changes in light thereof will be suggested to persons skilled in the art and are included within the spirit and purview of this application and are considered within the scope of the appended claims. For example, the relative quantities of the ingredients may be varied to optimize the desired effects, additional ingredients may be added, and/or similar ingredients may be substituted for one or more of the ingredients described. Additional advantageous features and functionalities associated with the systems, methods, and processes of the present invention will be apparent from the appended claims. Moreover, those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

What is claimed is:

1. A method of controlling compression ignition in a compression igination (CI) combustion system, comprising:

introducing a combustion primer (CP) and oxygen into a cylinder of the CI combustion system before and/or during a compression cycle;

introducing a pilot charge of primary fuel reactant (p-PFR) into the cylinder before and/or at top dead center (TDC) of the cylinder, wherein the p-PFR and CP mixture radicalize or combust and form high energy reactive radicals; and

combining a main charge of PFR with the high energy ractive radicals and the oxygen, thereby causing the main charge of PFR to instatnaeously and/or homogenously combust or burn upon introduction into the cylinder.

2. The method of claim 1, wherein the step of introducing the p-PFR includes introducing the p-PFR with the CP and the oxygen at TDC of the cylinder.

3. The method of claim 1, wherein the step of introducing the p-PFR includes introducing the p-PFR after the CP and the oxygen.

4. The method of claim 1, wherein the step of introducing the p-PFR includes introducing the p-PFR a plurality of times for a given compression cycle.

5. The method of claim 1, wherein the step of combining the main charge of PFR includes at least one of injecting the PFR in the intake air, fumigation, or direct injection of the PFR into the cylinder.

6. The method of claim 1, wherein the CP includes at least one of a C1-C8 hydrocarbon, liquefied petroleum gas (LPG), tertiary butyl hydroperoxide or combinations thereof.

7. The method of claim 1, wherein the CP includes Nitrous Oxide.

8. The method of claim 1, wherein combining the main charge of PFR includes introducing the PFR into the cylinder at about TDC.

9. The method of claim 1, wherein the step of introducing the p-PFR to radicalize or combust includes allowing the p-PFR to fully radicalize or combust at or before TDC.

10. The method of claim 1, further comprising controlling the introduction and/or combination of at least one of the the CP, pilot charge of PFR, main charge of PFR, or the oxygen using an open loop controller using predetermined data.

11. The method of claim 10, wherein the step of controlling the introduction includes controlling an amount of the CP, the oxygen, and/or the PFR that is introduced into the cylinder.

12. The method of claim 10, further comprising switching to a closed loop feedback controller if one or more conditions are exceeded based at least one sensor.

13. The method of claim 1, wherein the concentration of CP relative to 0₂ in the cylinder is maintained below the lower flammatory limit (LFL) or above the upper flammatory limit (UFL).

14. The method of claim 13, wherein the p-PFR raises the LFL of the CP/p-PFR/0₂ mixture and intiates formation of a pre-combustion state of matter including the high energy reactive radicals.

15. A combustion system, comprising:

a reciprocating engine having at least one cylinder and an air intake for providing intake oxygen (0₂) to the at least one cylinder;

a fuel introduction system comprising fuel injectors for a primary fuel reactant (PFR) and a combustion primer (CP); and

a control system including a memory having computer readable instructions stored thereon for controlling compression ignition in a compression igination (CI) combustion system, comprising: introducing a combustion primer (CP) and oxygen into a cylinder of the CI combustion system before and/or during a compression cycle;

combining a main charge of PFR with the radicalized CP/p-PFR mixture, and the oxygen to cause the main charge of PFR to instatnaeously and/or homogenously burn upon inctroduction into the cylinder due to the generation of radicals by the CP/p-PFR.

16. A non-transitory computer readable medium comprising a list of computer executable instruction for controlling compression ignition in a compression igination (CI) combustion system, the list of instructions comprising:

combining a main charge of primary fuel reactant (PFR) with the radicalized CP/p-PFR mixture, and the oxygen to cause the main charge of PFR to instatnaeously and/or homogenously combust or burn upon inctroduction into the cylinder due to the generation of radicals by the CP/p-PFR.