Turbulent Jet Controlled Compression Ignition (TJCCI) Engine

Abstract

A method of operating an engine includes operating the engine within first and second engine operating map regions (306 and 308) by performing passive jet ignition combustion with a first stoichiometric fuel mixture and a first volume of residual gas. The engine is operated within a third engine operating map region (310) by performing turbulent jet controlled compression ignition (TJCCI) combustion with an ultra-lean fuel mixture and the first volume of cooled exhaust gas recirculation, within a fourth engine operating map region (312) by performing passive jet ignition combustion with the third stoichiometric fuel mixture and the second volume of cooled exhaust gas recirculation, and within a fifth engine operating map region (314) characterized by stopping the engine. The engine is operated within a mode transition region between the second, third, and fourth engine operating map regions (308, 310, and 312) by performing passive jet ignition combustion with a second stoichiometric fuel mixture and a second volume of residual gas.

Description

[Background technology]

[0001] Internal combustion engines generally may operate by combusting a fuel mixture in a main combustion chamber, which may move one or more components within the engine. A typical internal combustion engine may include multiple cylinders defining main chambers within an engine block, with combustion within the cylinders moving internal pistons, which may in turn move the engine's crankshaft. The fuel mixture may be introduced into the main chamber through an inlet and combusted.

[0002] Combustion in the main chamber of an internal combustion engine can occur using a variety of mechanisms, including high pressure and temperature conditions or an ignition device. A typical ignition device configuration requires a continuous ignition source, or spark, to spark the air-fuel mixture in the main chamber of the engine, resulting in combustion. Traditionally, a spark is generated by energizing a copper ignition rod and positioning the energized ignition rod within a predetermined distance from a grounded nickel or iridium plate, where the electrical difference between the energized ignition rod and the grounded plate generates a continuous spark. Alternatively, a portion of the air-fuel mixture may be ignited in a pre-chamber, where it ignites the air-fuel mixture, and the resulting combustion reaction is released into the main chamber, igniting the remainder of the air-fuel mixture. After combustion in the main chamber, combustion products may be exhausted from an outlet of the main chamber.

[0003] After combustion in the main chamber, the products of combustion may be discharged as exhaust gas from an outlet of the main chamber. Some internal combustion engines use exhaust gas recirculation (EGR) technology, which recirculates a portion of the engine's exhaust gas back into the main chamber for mixing with air and fuel. By recirculating exhaust gases back into the main chamber of an internal combustion engine, the EGR system dilutes the amount of oxygen present during combustion, thereby reducing the combustion temperature in the main chamber and reducing nitrous oxide (NO ) emissions from the engine. x ) emissions can be reduced.

[0004] The timing and control of valves and combustion within the engine is often electronically controlled by a computer system that can implement a predetermined schedule of operations to allow the mixture of fuel and air into the main chamber, the combustion of the mixture, and the exhaust. Summary of the Invention [Means for solving the problem]

[0005] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0006] In one aspect, embodiments disclosed herein relate to a method of operating an engine, the method may include operating the engine within a first engine operating map region and a second engine operating map region by performing passive jet ignition combustion with a first stoichiometric fuel mixture and a first volume of residual gas; operating the engine within a third engine operating map region by performing turbulent jet controlled compression ignition (TJCCI) with an ultra-lean fuel mixture and the first volume of cooled exhaust gas recirculation; operating the engine within a fourth engine operating map region by performing passive jet ignition combustion with the third stoichiometric fuel mixture and the second volume of cooled exhaust gas recirculation; and operating the engine within a fifth engine operating map region, wherein the fifth engine operating map region is characterized by stopping the engine. The engine may also operate within a mode transition region between the second, third, and fourth engine operating map regions by implementing passive jet ignition combustion using a second stoichiometric fuel mixture and a second volume of residual gas, where the second volume of residual gas is controlled by ignition timing to meet a target engine load. The engine may have a cycle spanning two revolutions of a piston within the engine, where the cycle includes an exhaust stroke, an intake stroke, a compression stroke, and an expansion stroke, a gas exchange top dead center piston position located between the exhaust stroke and the intake stroke, an ignition top dead center piston position located between the compression stroke and the expansion stroke, and a bottom dead center piston position located between the intake stroke and the compression stroke and between the expansion stroke and the exhaust stroke.

[0007] In another aspect, embodiments disclosed herein relate to a turbulent jet-controlled compression ignition (TJCCI) engine system. The TJCCI engine system may include an engine having an engine block with a cylinder, a piston configured to move up and down within a main chamber of the cylinder, an auxiliary chamber in fluid communication with the main chamber, and a fuel injector mounted to the engine block and in fluid communication with the main chamber. The TJCCI engine system may also include a computer system with a memory and a processor in communication with the piston, exhaust valves, intake valves, one or more fuel injectors, and spark plugs. The computer processor operates the engine within a first engine operating map region and a second engine operating map region by performing passive jet ignition combustion with a first stoichiometric fuel mixture and a first volume of residual gas; operates the engine within a mode transition region by performing passive jet ignition combustion with a second stoichiometric fuel mixture and a second volume of residual gas, where the second volume of residual gas is controlled by ignition timing to meet a target engine load; and operates the engine within a mode transition region by performing passive jet ignition combustion with an ultra-lean fuel mixture and a first volume of cooled exhaust gas recirculation. operating the engine within a third engine operating map region by implementing turbulent jet controlled compression ignition (TJCCI) using a second stoichiometric fuel mixture; operating the engine within a mode transition region; operating the engine within a fourth engine operating map region by implementing passive jet ignition combustion using a third stoichiometric fuel mixture and a second volume of cooled exhaust gas recirculation; and operating the engine within a fifth engine operating map region, the fifth engine operating map region being characterized by shutting down the engine.

[0008] In yet another aspect, embodiments disclosed herein relate to a method that includes designing an engine to operate with passive jet ignition combustion under a first set of engine parameters. The passive jet ignition combustion may include injecting fuel from a fuel injector into a main chamber of the engine, directing a quantity of fuel into a pre-chamber to provide a pre-chamber mixture in the pre-chamber and a main chamber mixture in the main chamber, generating a spark in the pre-chamber to ignite the pre-chamber mixture, and discharging the ignited pre-chamber mixture from the pre-chamber into the main chamber to ignite the main chamber mixture. The first set of engine parameters may include an engine speed ranging from a first minimum speed to a first maximum speed and an engine load ranging from a first minimum load to a first maximum load, where a ratio of fuel to air provided in the main and pre-chambers after injection is stoichiometric under the first set of engine parameters. The method may also include designing the engine to operate with passive jet ignition combustion under a second set of engine parameters, the second set of engine parameters including an engine speed ranging from greater than the first maximum speed to a second maximum speed and an engine load ranging from a first minimum load to a second maximum load. The method may also include designing the engine to change the ratio of fuel to air provided into the main and pre-chambers to an ultra-lean ratio (more air than fuel) when the engine is operated under a third set of engine parameters, where the engine speed is greater than the first maximum speed and the engine load is greater than the second maximum load under the third set of engine parameters.

[0009] Other aspects and advantages of the claimed subject matter will become apparent from the following description and appended claims.

[0010] Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in various figures are designated with like reference numerals for consistency. The sizes and relative positions of elements in the figures are not necessarily drawn to scale. For example, the shapes and angles of various elements are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve the readability of the figures. Furthermore, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements, but have been selected merely for ease of recognition in the figures. [Brief explanation of the drawings]

[0011] [Figure 1] 1 illustrates a combustion system according to one or more embodiments.

[0012] [Figure 2] 1 illustrates an apparent heat release rate profile according to one or more embodiments.

[0013] [Figure 3] 1 illustrates an engine operating map according to one or more embodiments.

[0014] [Figure 4] 1 illustrates an engine timing chart according to one or more embodiments.

[0015] [Figure 5] 1 illustrates an engine timing chart according to one or more embodiments.

[0016] [Figure 6] 1 illustrates an engine timing chart according to one or more embodiments.

[0017] [Figure 7] 1 illustrates an engine timing chart according to one or more embodiments.

[0018] [Figure 8] 1 illustrates a computer system according to one or more embodiments.

[0019] [Figure 9] 1 illustrates a flowchart in accordance with one or more embodiments.

[0020] [Figure 10] 1 illustrates a flowchart in accordance with one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0021] In the following detailed description of embodiments of the present disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0022] Throughout this application, ordinal numbers (e.g., first, second, third, etc.) may be used as adjectives for elements (i.e., any noun in this application). The use of ordinal numbers does not imply or create a particular order of elements, nor does it limit an element to only a single element, unless expressly disclosed, such as by use of the terms "before," "after," "single," and other such terms. Rather, the use of ordinal numbers distinguishes each element. As an example, a first element may be distinct from a second element, and the first element may encompass multiple elements and follow (or precede) the second element in the order of elements.

[0023] In the following description of Figures 1-10, in various embodiments disclosed herein, components described with respect to one figure may be equivalent to one or more similarly named components described with respect to other figures. For brevity, the description of these components may not be repeated in each figure. Accordingly, any and all embodiments of the components in each figure are incorporated by reference and are assumed to be optionally present in all other figures having one or more similarly named components. Furthermore, according to various embodiments disclosed herein, the description of a component in one figure should be interpreted as an optional embodiment that may be implemented in addition to, in conjunction with, or instead of the embodiment described with respect to the corresponding similarly named component in the other figures.

[0024] In one aspect, embodiments disclosed herein relate to methods and systems for implementing turbulent jet controlled compression ignition (TJCCI) to improve engine efficiency and reduce nitrogen oxide emissions. In another aspect, embodiments disclosed herein relate to methods for passively fueling a pre-chamber and implementing various combustion strategies associated with designed engine operating maps. In yet another aspect, embodiments disclosed herein relate to methods for designing an engine to operate within multiple engine operating regions depending on engine speed and engine load.

[0025] Referring to FIG. 1 , a combustion system 100 according to an embodiment disclosed herein is shown. The combustion system 100 may be an internal combustion engine including at least one cylinder 101 formed within an engine body or engine block 102. While FIG. 1 illustrates only a portion of the engine block and only one cylinder within the engine block, the engine block may have several cylinders. The cylinder 101 may include a main chamber 103. The main chamber 103 may be a combustion chamber of the combustion system 100. Furthermore, a cylinder head 104 may be attached to the top of the cylinder 101 and form an upper end of the main chamber 103. A piston 105 may be disposed within the cylinder 101 and form a lower end of the main chamber 103. The piston 105 moves up and down within the cylinder 101 during an engine cycle, and the volume of the main chamber 103 changes depending on the position of the piston 105. Furthermore, the piston 105 may be connected to a crankshaft (not shown) by a connecting rod. A crankshaft may convert the reciprocating motion of the pistons 105 into rotary motion, as is well known in the art.

[0026] An antechamber 117 may be disposed in fluid communication with the main chamber 103. The antechamber 117, according to one or more embodiments, may have a much smaller volume than the main chamber 103. For example, in one or more embodiments, the antechamber 117 may have a volume between 0.5 cubic centimeters and 3 cubic centimeters, while the main chamber 103 may have a swept volume of over 300 cubic centimeters.

[0027] The pre-chamber 117 may have one or more nozzles integrally formed through the wall of the pre-chamber 117 to provide fluid communication between the pre-chamber 117 and the main chamber 103. In some embodiments, the nozzles may be formed from a nozzle insert extending through the pre-chamber wall to provide fluid communication between the pre-chamber 117 and the main chamber 103. The one or more nozzles are configured to accelerate fuel as it moves from the main chamber 103 to the pre-chamber 117 due to piston compression during the compression stroke, thereby improving fuel vaporization and mixing. A spark plug 118 may be connected to and configured to interface with the pre-chamber 117. The spark plug 118 may be used to ignite fuel in the pre-chamber 117, after which a partially or fully combusted mixture may be ejected through the one or more nozzles into the main chamber 103.

[0028] A fuel injector 107 according to an embodiment of the present disclosure may be mounted within the cylinder head 104. A clamp (not shown) may removably secure the fuel injector 107 to the cylinder head 104. The clamp may be disposed on top of the fuel injector 107 and attached to the cylinder head 104 to hold the position of the fuel injector 107. The fuel injector 107 may be aligned, coaxial, or angled relative to the cylinder axis of the cylinder head 104. In one example, installing the fuel injector 107 in the cylinder head 104 includes forming one or more atomizing nozzle assemblies. In some embodiments, the nozzle assemblies may include fuel channels, premixer tubes, and ports formed within the tip of the fuel injector 107. The fuel injector 107 may be in fluid communication with the main chamber 103, in which case one or more atomizing nozzle assemblies may be positioned such that the orifices of the atomizing nozzle assemblies are in fluid communication with the main chamber 103.

[0029] In one or more embodiments, the one or more spray nozzle assemblies may have a wide spray angle. A first of the one or more spray nozzle assemblies may be aimed at and aligned with one of the nozzles in the pre-chamber 117. This first spray nozzle assembly may be configured to passively fuel the pre-chamber 117 while actively fueling the main chamber 103.

[0030] Continuing with reference to FIG. 1 , the cylinder head 104 may optionally include a second fuel injector 108 used in combination with the fuel injector 107. As shown, the cylinder head 104 may include at least one intake passage 119 terminating in a second intake port 110. The second fuel injector 108 may be disposed along the intake passage 119 in a configuration that enables injection of fuel into the intake passage 119. The second fuel injector 108 may be a fuel injector similar to the fuel injector 107. Further, the intake port 110 may include an intake valve 113 for controlling the opening and closing of the intake port 110. Air flowing through the intake passage 119 into the main chamber 103 may be entrained in the fuel spray plume of the second fuel injector 108 when the second fuel injector 108 is injecting fuel. Although not shown, the main chamber 103 and the intake passage 119 may be connected to an air source in a conventional manner. The air in the main chamber 103 and intake passage 119 may be ambient air or a mixture of ambient air and recirculated exhaust gases.

[0031] The cylinder head 104 may also include at least one exhaust passage 111 having an exhaust port 112. An exhaust valve 114 may be positioned to control the opening and closing of the exhaust port 112. When the exhaust port 112 is open, exhaust gases may be forced from the main chamber 103 into the exhaust passage 111. An intake passage 119, exhaust passage 111, and associated components (e.g., valves 113, 114, and fuel injectors 107, 108) may be provided in the cylinder head 104 for each cylinder in the combustion system 100, for example, in the arrangement shown in FIG. 1 for cylinder 101.

[0032] In one or more embodiments, the fuel injectors 107, 108 may be used to inject fuel directly into the main chamber 103 and / or the intake passage 119. The fuel injectors 107, 108 may be fluidly connected to a fuel line 115 that is in communication with a fuel supply 116.

[0033] In one or more embodiments, the computer 120 may include a control system, such as an engine control unit, that may control the opening and closing of the fuel injectors 107, 108 to deliver fuel into the main chamber 103 at desired times during the engine cycle. The control system may also control the opening and closing of the intake and exhaust valves 113, 114. In one or more embodiments, the computer 120 may include a user interface panel and a processor that allows a user to provide input, such as commands, to the computer 120.

[0034] In some embodiments, cables (not shown), such as electrical or hydraulic power cables, may be coupled to the fuel injectors 107, 108. The cables may provide power to the fuel injectors 107, 108 from a power source (not shown). Additionally, the cables may be connected to a computer 120 to control the fuel injectors 107, 108. The computer 120 may contain instructions or commands to automatically operate the fuel injectors 107, 108, or a user may manually control the computer 120 at a user interface panel (not shown). It is further envisioned that the computer 120 may be connected to an office via satellite to allow a user to remotely monitor the status and send commands to the fuel injectors 107, 108. If leaks or performance issues are found, an alert may be sent to a control system to manually or automatically adjust or turn off the fuel injectors 107, 108.

[0035] In one or more embodiments, the combustion system 100 may be used to implement turbulent jet controlled compression ignition (TJCCI). TJCCI may involve passively fueling the pre-chamber 117 and igniting the fuel within the pre-chamber 117. In one or more embodiments, as described above, the pre-chamber 117 may be passively fueled by precisely aligning one of the fuel injector's atomizing nozzle assemblies with the pre-chamber nozzle. In other embodiments, the pre-chamber 117 may be passively fueled via a rebound fuel jet, which may initially be generated by the fuel injector 107 and enter the pre-chamber 117 via one or more nozzles by rebounding off the piston 105 or other main chamber interior surface. TJCCI may also be implemented by active fueling of the pre-chamber 117 using a third fuel injector (not shown) disposed within the pre-chamber 117. According to embodiments of the present disclosure, TJCCI may be characterized by injecting a turbulent mixture into the main combustion chamber 103, increasing the temperature and pressure of the mixture to cause compression ignition (or autoignition), and associated engine operating maps (described with respect to FIGS. 4-7). Additionally, TJCCI may also be characterized by specific timing diagrams, embodiments of which are also described with respect to FIGS. 4-7. Thus, the pre-chamber 117 may be fueled, either actively or passively, in any manner or configuration without departing from the scope of the present disclosure. Similarly, TJCCI may be implemented according to the methods described herein in combination with any pre-chamber fueling strategy without departing from the scope of the present disclosure.

[0036] 2, which illustrates an apparent heat release rate profile 200 and a corresponding spark timing profile 210 from a spark plug according to one or more embodiments. In one or more embodiments, the apparent heat release rate profile 200 may represent engine crank angle on a horizontal axis 202 and the apparent heat release rate on a vertical axis 204. The apparent heat release rate profile contrasts the apparent heat release rate of jet ignition without autoignition (a simple jet ignition process), represented by dashed line 206, with the apparent heat release rate of TJCCI, represented by solid line 208.

[0037] In contrast to a simple jet ignition process, which may use a spark in conjunction with a pre-chamber, the TJCCI process may use jet ignition to control compression ignition in the main chamber. A benefit of implementing TJCCI may be a slower initial heat release rate compared to processes in which the entire premixed mixture autoignites in the main chamber, such as homogeneous charge compression ignition (HCCI) or homogeneous gasoline compression ignition (HCM). This may be shown, for example, in the circled area 212. The slower initial heat release rate may reduce the pressure rise rate of the combustion process, which may reduce engine combustion noise. Furthermore, during a simple jet ignition process, combustion heat release is slow after the initial peak, which is not optimal for complete combustion and piston work extraction. On the other hand, TJCCI may induce a second heat release peak, which accelerates the combustion of the remaining mixture and improves combustion and thermal efficiency.

[0038] Additionally, the initiation of combustion in TJCCI may be controlled by the spark plug 118 rather than a kinetic reaction that may be highly dependent on the thermal boundary conditions of the engine. Combustion via the spark plug 118 may be more robustly controlled under various transient operating conditions.

[0039] 3 illustrates an engine operating map according to one or more embodiments. The concept of TJCCI may be visually represented in the form of an engine operating map 300. In one or more embodiments, engine operating map 300 may have engine load represented on a vertical axis 304 and engine speed represented on a horizontal axis 302.

[0040] The operating map 300 may have five distinct engine operating map regions. Each distinct engine operating map region follows four different combustion strategies. The first engine operating map region 306 may have engine parameters characterized by a low engine speed and an engine load ranging from a low engine load to a medium engine load. More specifically, the first set of engine parameters may include an engine speed ranging from a first minimum speed 318 to a first maximum speed 320 and an engine load ranging from a first minimum load 322 to a first maximum load 324. For example, in some embodiments, the first set of engine parameters may include an engine speed ranging from 200 to 1500 rpm and an engine load ranging from 0 bar BMEP (brake mean effective pressure) to 15 bar.

[0041] The second engine operating map region 308 may have engine parameters characterized by low engine loads and engine speeds ranging from low to medium engine speeds. More specifically, the second set of engine parameters may include engine speeds ranging from greater than a first maximum speed 320 to a second maximum speed 326 and engine loads ranging from a first minimum load 322 to a second maximum load 328. The second maximum load 328 may be less than the first maximum load 324. For example, in some embodiments, the second set of engine parameters may include engine speeds ranging from 700 to 4,500 rpm and engine loads ranging from 0 bar to 5 bar.

[0042] Within the first and second engine operating map regions 306, 308, the engine may perform passive jet ignition combustion using a stoichiometric mixture and a small amount of residual gas, which may be expressed as:

number

[0043] The third engine operating map region 310 may have engine parameters characterized by medium engine speeds and medium engine loads. In one or more embodiments, under the third set of engine parameters, the engine speed ranges from a first maximum speed 320 to a second maximum speed 326, and the engine load ranges from a second maximum load 328 to a third maximum load 330. The third maximum load 330 may be less than the first maximum load 324. For example, in some embodiments, the third set of engine parameters may include an engine speed range of 700 to 4,500 rpm and an engine load range of 3 to 12 bar. Within the third engine operating map region 310, the engine may perform TJCCI using an ultra-lean mixture and a small amount of cooled exhaust gas residual (EGR). An ultra-lean fuel mixture, according to one or more embodiments, may refer to a fuel mixture with a high fuel-to-air ratio. For example, an ultra-lean mixture may include approximately 1.5 to 2.5 times more air than the stoichiometric amount of fuel. Such a fluid mixture may result in high engine efficiency, high fuel efficiency, and low nitrogen oxide emissions. In particular, nitrogen oxide emissions may be lower compared to spark or plasma-assisted compression ignition concepts due to improved fuel mixing near the spark plug 118 gap. In one or more embodiments, the engine may be operated heavily within the third engine operating map region 310 during a typical vehicle driving cycle.

[0044] The fourth engine operating map region 312 may have engine parameters characterized by engine speed and engine load, both of which range from medium to high. Under the fourth set of engine parameters, the engine speed may range from greater than the first maximum speed 320 to a fourth maximum speed 332 (which may be greater than the second maximum speed 326), and the engine load may generally range from greater than the third maximum load 330 to the first maximum load 324. Note, however, that the engine load across the fourth region 316 may not fall within a fixed range and may vary with engine speed. For example, above the second maximum speed 326, the engine load may vary between the second maximum load 328 and the first maximum load 324. For example, in some embodiments, the fourth set of engine parameters may include an engine speed range of 700 to 6,500 rpm and an engine load range of 10 to 25 bar.

[0045] Within the fourth engine operating map region 312, the engine may perform passive jet ignition combustion using a stoichiometric mixture and a moderate amount of cooled EGR. TJCCI may not be applicable at high engine loads due to high intake boost requirements, high pressure rise rates, and high peak combustion pressures. Additionally, TJCCI may not be applicable at high engine speeds due to the long ignition delay time relative to high engine speeds. In contrast, passive jet ignition performed with a stoichiometric mixture and a moderate amount of cooled EGR may improve knock compared to spark ignition under similar mixture conditions, given the rapid consumption of end gases.

[0046] The fifth engine operating map 314 may have engine parameters characterized by an engine shutdown. For example, in some embodiments, the fifth set of engine parameters may include an engine speed in the range of 4,000 to 6,500 rpm and an engine load in the range of 0 to 10 bar.

[0047] A mode transition region 316 may be located between the second and third engine operating regions 308, 310 and between the third and fourth engine operating regions 310, 312. Within the mode transition region 316, the engine may run passive jet ignition with a stoichiometric mixture and a small amount of residual gas, which may be controlled by different ignition timings selected to meet different engine load targets.

[0048] In one or more embodiments, the mode transition region 316 may represent a change in combustion strategy, specifically, a transition from a stoichiometric mixture to a lean mixture (i.e., between the second and third engine operating map regions 308, 310) or a transition from a lean mixture to a stoichiometric mixture (i.e., between the third and fourth operating map regions 310, 312). In one or more embodiments, the transition may be managed by operating the engine with a stoichiometric mixture and varying fuel injection quantity and spark timing on a cycle-by-cycle basis to reduce crankshaft work output. Because stoichiometric combustion is very robust, the transition may be more stable. However, during the mode transition region 316, engine efficiency may be reduced due to the retardation of combustion phasing required to reduce work output.

[0049] In one or more embodiments, computer 120 may be programmed according to engine operating map 300. For example, engine operating map 300 may be executed in computer 120 (often referred to as an engine control unit (ECU)), which may have all necessary engine control parameters already calibrated to the entire engine operating map 300. The software executed by computer 120 may be specially written by the original engine manufacturer (OEM) to work with the particular engine being used.

[0050] 4, which illustrates an engine timing chart 400 for an engine operating within the first and second operating map regions 306, 308, according to one or more embodiments. An engine timing chart, such as engine timing chart 400, may represent the four strokes of the engine (exhaust, intake, compression, and expansion) and the timing of actuation of the respective exhaust and intake valves, fuel injection timing, and spark timing. Referring back to FIG. 1, in one or more embodiments, each engine cycle may correspond to two revolutions (four strokes) of the piston 105 in the cylinder 101.

[0051] 1 and 4, during the exhaust stroke 402 of the engine, a port fuel injection procedure may be performed. In one or more embodiments, the port fuel injection procedure, visually indicated within region 403, may be performed by the second fuel injector 108 shown in FIG. 1. Additionally, during the exhaust stroke, the exhaust valve 114 may be actuated as visually indicated by curve 404. Between the exhaust stroke 402 and the intake stroke 406, the piston 105 may reach its first top dead center position (sometimes referred to as gas exchange top dead center 408).

[0052] Shortly after gas exchange top dead center 408, during the intake stroke 406, the intake valve 113 may be actuated as visually shown by curve 409. Additionally, a direct injection fueling procedure 410 may be performed using the first fuel injector 107 shortly after the piston 105 reaches gas exchange top dead center 408. In one or more embodiments, the first fuel injector 107 may passively fuel the auxiliary chamber 117 and actively fuel the main chamber 103.

[0053] The piston 105 may reach a bottom dead center position 412 between the intake stroke 406 and the compression stroke 414, and between the expansion stroke 416 and the exhaust stroke 402. The piston 105 may reach a second top dead center position (sometimes referred to as ignition top dead center 418) between the compression stroke 414 and the expansion stroke 416. The spark plug 118 may generate a spark 420 to ignite fuel in the pre-chamber 117 during the compression stroke 414 before the piston 105 reaches ignition top dead center 418.

[0054] 1 and 5, FIG. 5 illustrates an engine timing diagram 500 for an engine operating within the third operating map region 310, according to one or more embodiments. During the exhaust stroke 402 of the engine, a port fuel injection maneuver may be performed. In one or more embodiments, the port fuel injection maneuver, visually represented within region 403, may be performed by the second fuel injector 108 shown in FIG. 1. Additionally, during the exhaust stroke, the exhaust valve 114 may be actuated as visually represented by curve 404. Shortly after gas exchange top dead center 408, during the intake stroke 406, the intake valve 113 may be actuated as visually represented by curve 409. In other words, the intake valve 113 may be actuated at the beginning of the intake stroke 406.

[0055] After the piston passes bottom dead center 412, a direct injection fueling procedure 410 may be performed using the first fuel injector 107 during the compression stroke 414. In one or more embodiments, the first fuel injector 107 may passively fuel the pre-chamber 117 and actively fuel the main chamber 103. The spark plug 118 may generate a spark 420 to ignite the fuel in the pre-chamber 117 during the compression stroke 414 before the piston 105 reaches firing top dead center 418.

[0056] 1 and 6, FIG. 6 illustrates an engine timing diagram 600 for an engine operating within the fourth operating map region 312, according to one or more embodiments. During the exhaust stroke 402 of the engine, a port fuel injection maneuver may be performed. In one or more embodiments, the port fuel injection maneuver, visually represented within region 403, may be performed by the second fuel injector 108 shown in FIG. 1. Additionally, during the exhaust stroke, the exhaust valve 114 may be actuated as visually represented by curve 404. Partway through the intake stroke 406, the intake valve 113 may be actuated as visually represented by curve 409.

[0057] A direct injection fueling procedure 410 may be performed using the first fuel injector 107 during actuation of the intake valve 113 during the intake stroke 406. In one or more embodiments, the first fuel injector 107 may passively fuel the pre-chamber 117 and actively fuel the main chamber 103. The spark plug 118 may generate a spark 420 to ignite the fuel in the pre-chamber 117 during the compression stroke 414 before the piston 105 reaches ignition top dead center 418.

[0058] 7, which illustrates an engine timing diagram 700 for an engine operating within the transition mode region 316, according to one or more embodiments. Referring to FIGS. 1 and 7, during the exhaust stroke 402 of the engine, a port fuel injection maneuver may be performed. In one or more embodiments, the port fuel injection maneuver, visually illustrated within region 403, may be performed by the second fuel injector 108, shown in FIG. 1. Additionally, during the exhaust stroke, the exhaust valve 114 may be actuated as visually illustrated by curve 404.

[0059] Shortly after gas exchange top dead center 408, during the intake stroke 406, the intake valve 113 may be actuated as visually shown by curve 409. Additionally, a direct injection fueling procedure 410 may be performed using the first fuel injector 107 shortly after the piston 105 reaches gas exchange top dead center 408. In one or more embodiments, the first fuel injector 107 may passively fuel the auxiliary chamber 117 and actively fuel the main chamber 103.

[0060] The spark plug 118 may generate a spark 420 to ignite fuel in the pre-chamber 117 at a selected time during the engine cycle between the compression stroke 414 before the piston 105 reaches ignition top dead center 418 and the expansion stroke 416 after the piston 105 passes ignition top dead center 418. Spark timing may be selected based on various engine operating needs.

[0061] 8 illustrates a block diagram of a computer system 802 that may be used to provide the computational functionality associated with the described algorithms, methods, functions, processes, flows, and procedures as described in this disclosure, according to one or more embodiments. The illustrated computer 802 is intended to encompass any computing device, such as a server, desktop computer, laptop / notebook computer, wireless data port, smartphone, personal digital assistant (PDA), tablet computing device, one or more processors within these devices, or other suitable processing device (including both physical and virtual instances of a computing device). Additionally, computer 802 may include a computer that includes input devices, such as a keypad, keyboard, touchscreen, or other device capable of receiving user information, and output devices that communicate information related to the operation of computer 802, including digital data, visual or audio information (or a combination of information), or a GUI.

[0062] The computer 802 may act as a client, a network component, a server, a database or other persistence, or any other component of a computer system for implementing the subject matter described in this disclosure (or a combination of roles). The illustrated computer 802 is communicatively coupled to a network 830. In some implementations, one or more components of the computer 802 may be configured to operate within an environment, including a cloud computing-based, local, global, or other environment (or combination of environments).

[0063] Generally speaking, computer 802 is an electronic computing device operable to receive, transmit, process, store, or manage data and information related to the described subject matter. According to some implementations, computer 802 may also include or be communicatively coupled to an application server, email server, web server, caching server, streaming data server, business intelligence (BI) server, or other server (or combination of servers).

[0064] Computer 802 can receive requests over network 830 from client applications (e.g., running on another computer 802) and respond to the received requests by processing the requests with an appropriate software application. In addition, requests may also be sent to computer 802 from internal users (e.g., from a command console or by other suitable access methods), external or third parties, other automated applications, and any other suitable entity, individual, system, or computer.

[0065] The components of computer 802 can communicate using system bus 803. In some implementations, any or all of the components (either hardware or software (or a combination of hardware and software)) of computer 802 may interface with each other or with interface 804 (or a combination of both) via system bus 803 using an application programming interface (API) 812 or service layer 813 (or a combination of API 812 and service layer 813). API 812 may include specifications of routines, data structures, and object classes. API 812 may be computer language independent or dependent and may refer to a complete interface, a single function, or even a set of APIs. Service layer 813 provides software services to computer 802 or other components (whether shown or not) communicatively coupled to computer 802. The functionality of computer 802 may be accessible to all service consumers using this service layer. Software services, such as those provided by service layer 813, provide reusable, defined business functions through defined interfaces. For example, the interface may be software written in JAVA, C++, or another suitable language that provides data in Extensible Markup Language (XML) format or another suitable format. Although shown as an integrated component of computer 802, alternative implementations may depict API 812 or services layer 813 as standalone components associated with other components of computer 802 or other components (whether shown or not) communicatively coupled to computer 802. Furthermore, any or all portions of API 812 or services layer 813 may be implemented as a child module or sub-module of another software module, enterprise application, or hardware module without departing from the scope of the present disclosure.

[0066] Computer 802 includes an interface 804. While a single interface 804 is shown in FIG. 8, more than one interface 804 may be used according to the particular needs, desires, or particular implementation of computer 802. Interface 804 is used by computer 802 to communicate with other systems in a distributed environment connected to network 830. Generally, interface 804 includes logic encoded in software or hardware (or a combination of software and hardware) operable to communicate with network 830. More specifically, interface 804 may include software supporting one or more communication protocols related to communication such that network 830 or interface hardware is operable to communicate physical signals within and outside of illustrated computer 802.

[0067] Computer 802 includes at least one computer processor 805. While shown in Figure 8 as a single computer processor 805, more than one processor may be used according to the particular needs, desires, or particular implementation of computer 802. Generally, computer processor 805 executes instructions and manipulates data to perform the operations of computer 802 and any machine learning networks, algorithms, methods, functions, processes, flows, and procedures as described in this disclosure.

[0068] The computer 802 also includes a memory 806 that holds data for the computer 802 or other components (or a combination of both), which may be connected to the network 830. For example, the memory 806 may be a database that stores data consistent with the present disclosure. While shown in FIG. 8 as a single memory 806, two or more memories may be used according to the particular needs, desires, or particular implementation of the computer 802 and the described functionality. While the memory 806 is shown as an integral component of the computer 802, in alternative implementations, the memory 806 may be external to the computer 802.

[0069] Application 807 is an algorithmic software engine that provides functionality according to the specific needs, desires, or specific implementation of computer 802, particularly with respect to the functionality described in this disclosure. For example, application 807 can function as one or more components, modules, applications, etc. Furthermore, while shown as a single application 807, application 807 may be implemented as multiple applications 807 on computer 802. Additionally, while shown as integral to computer 802, in alternative implementations application 807 can be external to computer 802.

[0070] Any number of computers 802 may be associated with or external to the computer system that includes computer 802, with each computer 802 communicating via network 830. Furthermore, the terms "client," "user," and other appropriate terminology may be used interchangeably as appropriate without departing from the scope of this disclosure. Furthermore, this disclosure contemplates that many users may use one computer 802, or that one user may use multiple computers 802.

[0071] FIG. 9 illustrates a flowchart according to one or more embodiments. More specifically, FIG. 9 illustrates a flowchart 900 of a method for operating an engine under various engine operating map regions. Furthermore, one or more of the blocks in FIG. 9 may be performed by one or more components such as those described in FIGS. 1-8. While the blocks in FIG. 9 are presented and described sequentially, one skilled in the art will understand that some or all of the blocks may be performed in a different order, combined, or omitted, and some or all of the blocks may be performed in parallel. Furthermore, the blocks may be performed actively or passively.

[0072] Initially, the engine may be operated within the first operating map region 306 and the second operating map region 308 by performing passive jet ignition combustion using a first stoichiometric fuel mixture and a first volume of residual gas (S902). In one or more embodiments, operating the engine within the first and second operating map regions 306 may include operating the engine according to an engine timing chart 400. Specifically, during an exhaust stroke 402 of the engine, a port fuel injection procedure 403 may be performed, and the exhaust valve 114 may be actuated. At the beginning of an intake stroke 406, the intake valve 113 may be actuated. Furthermore, during the intake stroke 406, a direct injection procedure 410 may be performed immediately after the piston 105 passes gas exchange top dead center 408. During a compression stroke 414, a spark may be provided from the spark plug 118 before the piston reaches ignition top dead center 418.

[0073] The engine may then be operated within the mode transition region 316 by performing passive jet ignition combustion using the second stoichiometric fuel mixture and the second volume of residual gas (S904). In one or more embodiments, operating the engine within the mode transition region 316 may include operating the engine according to the engine timing chart 700. Specifically, during the exhaust stroke 402 of the engine, the port fuel injection procedure 403 may be performed and the exhaust valve 114 may be actuated. At the beginning of the intake stroke 406, the intake valve 113 may be actuated. Furthermore, during the intake stroke 406, the direct injection procedure 410 may be performed immediately after the piston 105 passes gas exchange top dead center 408. A first spark may be generated from the spark plug 118 during the compression stroke 414 immediately before the ignition top dead center 418. Alternatively, a spark may be generated from the spark plug 118 during the expansion stroke 416 immediately after the ignition top dead center 418.

[0074] The engine may then be operated within a third operating map region 310 by implementing turbulent jet controlled compression ignition (TJCCI) with an ultra-lean fuel mixture and a first volume of cooled exhaust gas recirculation (EGR) (S906). In one or more embodiments, operating the engine within the third operating map region 310 may include operating the engine according to an engine timing chart 500. Specifically, during the exhaust stroke 402 of the engine, a port fuel injection procedure 403 may be implemented and the exhaust valve 114 may be actuated. At the beginning of the intake stroke 406, the intake valve 113 may be actuated. During the compression stroke 414, a direct injection procedure 410 may be implemented after the piston 105 passes bottom dead center 412. Additionally, a spark may be generated from the spark plug 118 during the compression stroke 414 just before the piston 105 reaches ignition top dead center 418.

[0075] Following the third operating map region 310, the engine may once again be operated (S908) within the transition mode region 316. Similar to step S904, the engine may be operated according to the engine timing chart 700.

[0076] The engine may further be operated within a fourth engine operating map region 312 by performing passive jet ignition combustion using the third stoichiometric fuel mixture and the second volume of cooled EGR (S910). In one or more embodiments, operating the engine within the fourth engine operating map region 312 may include operating the engine according to the engine timing chart 600. Specifically, during the exhaust stroke 402 of the engine, a port fuel injection procedure 403 may be performed and the exhaust valve 114 may be actuated. During the intake stroke 406, the intake valve 113 may be actuated. Furthermore, during the intake stroke 406, a direct injection procedure 410 may be performed while the intake valve 113 is actuated during the intake stroke 406. Furthermore, a spark may be generated from the spark plug 118 during the compression stroke 414 just before the piston 105 reaches ignition top dead center 418.

[0077] In one or more embodiments, the transition from one engine operating map region to another engine operating map region may be controlled based at least in part on a desired engine load and a desired engine speed provided by a user to a computer system (e.g., computer 120 and computer 802).

[0078] In one or more embodiments, the second volume of cooled EGR required within the fourth operating map region 312 may be greater than the first volume of cooled EGR required within the third operating map region 310.

[0079] FIG. 10 illustrates a flowchart according to one or more embodiments. More specifically, FIG. 10 illustrates a flowchart 1000 of a method for designing an engine to operate under various combustion strategies. Furthermore, one or more of the blocks in FIG. 10 may be performed by one or more components as described in FIGS. 1-8. While the various blocks in FIG. 10 are presented and described sequentially, one skilled in the art will understand that some or all of the blocks may be performed in a different order, combined, or omitted, and some or all of the blocks may be performed in parallel. Furthermore, the blocks may be performed actively or passively.

[0080] Initially, the engine may be designed to operate using passive jet ignition combustion under a first set of engine parameters (S1002). In one or more embodiments, the first set of engine parameters may correspond to engine speeds and engine loads in a first engine operating map region 306. More specifically, the first set of engine parameters may include an engine speed ranging from a first minimum speed 318 to a first maximum speed 320 and an engine load ranging from a first minimum load 322 to a first maximum load 324. In one or more embodiments, the first minimum speed 318 and the first minimum load 322 may be described as low engine speed and low engine load, respectively. Further, the first maximum speed 320 and the first maximum load 324 may be described as medium engine speed and medium engine load, respectively. Under the first set of engine parameters, the ratio of fuel to air provided into the main and auxiliary combustion chambers 103, 117 after injection is a stoichiometric mixture.

[0081] In one or more embodiments, passive jet ignition combustion may include injecting fuel from a fuel injector 107 into the main chamber, where a quantity of fuel is directed into the pre-chamber 117 via one or more nozzles. This injection procedure may provide a pre-chamber mixture into the pre-chamber 117, and may provide a main chamber mixture into the main chamber 103, where the pre-chamber 117 is adjacent to and in fluid communication with the main chamber 103. Passive jet ignition combustion may further include generating a spark in the pre-chamber 117 to ignite the pre-chamber mixture and discharging the ignited pre-chamber mixture into the main chamber 103 to ignite the main chamber mixture.

[0082] The engine may also be designed to operate using passive jet ignition combustion under a second set of engine parameters (S1004). In one or more embodiments, the second set of engine parameters may correspond to engine speeds and engine loads in a second engine operating map region 308. More specifically, the second set of engine parameters may include engine speeds ranging from greater than first maximum speed 320 to a second maximum speed 326 and engine loads ranging from first minimum load 322 to a second maximum load 328. In one or more embodiments, second maximum speed 326 and second maximum load 328 may be described as a medium engine speed and a medium engine load, respectively.

[0083] Additionally, the engine may be designed to change the ratio of fuel to air provided within the main and auxiliary combustion chambers 103, 117 to an ultra-lean ratio when the engine is operated under a third set of engine parameters (S1006). In one or more embodiments, under the third set of engine parameters, the engine speed ranges from a first maximum speed 320 to a second maximum speed 326, and the engine load ranges from a second maximum load 328 to a third maximum load 330. Additionally, the ultra-lean ratio includes more air than fuel.

[0084] The method illustrated in flowchart 1000 may further include providing an engine operating map (such as engine operating map 300) that defines multiple regions of engine operation. Each region of engine operation may define a ratio of fuel to air provided in the main and auxiliary chambers 103, 117 under different engine parameters.

[0085] In one or more embodiments, the multiple regions may include a first region 306 defining a stoichiometric ratio of fuel to air under a first set of engine parameters and a second region 308 defining a stoichiometric ratio of fuel to air under a second set of engine parameters. A third region 310 may define an ultra-lean ratio of fuel to air under the third set of engine parameters. Under the third set of engine parameters, the engine speed may range from greater than a first maximum speed 320 to a second maximum speed 326, and the engine load may range from greater than a second maximum load 328 to a third maximum load 330. A fourth region 312 may define a stoichiometric ratio of fuel to air under a fourth set of engine parameters. Under the fourth set of engine parameters, the engine speed may range from greater than the first maximum speed 320 to a fourth maximum speed 332, and the engine load may generally range from greater than the third maximum load 330 to the first maximum load 324. Note, however, that the engine load across the fourth region 316 may not fall within a fixed range but may vary with engine speed. For example, above the second maximum speed 326, the engine load may vary between the second maximum load 328 and the first maximum load 324.

[0086] In one or more embodiments, the engine operating map 300 may further define a third region 310 as having a first amount of cooled EGR provided with an ultra-lean fuel to air ratio. Additionally, a fourth region 312 may be defined as having a second amount of cooled EGR provided with a stoichiometric fuel to air ratio. In one or more embodiments, the second amount of cooled EGR may be greater than the first amount of EGR. Furthermore, operating the engine under various different regions and corresponding timing parameters includes injecting fuel at different times during the cycle of the piston 105 within the main chamber 103.

[0087] Embodiments of the present disclosure may provide at least one of the following advantages: Turbulent jet-controlled compression ignition may help mix and vaporize fuel in the pre-chamber before ejecting into the main chamber; By allowing passive fueling of the pre-chamber, only a spark plug needs to be located in the pre-chamber, thereby maintaining a small pre-chamber volume; In contrast, engine embodiments in which fuel injectors are located in the pre-chamber necessarily require a larger pre-chamber volume, which may be undesirable; Furthermore, direct pre-chamber fuel injection reduces the time and distance that the fuel may need to properly vaporize; embodiments of the present disclosure that rely on passive pre-chamber fueling allow sufficient time and distance to promote proper mixing and vaporization of the fuel.

[0088] Implementing TJCCI instead of spark-assisted gasoline compression ignition improves the cycle-to-cycle repeatability of the local equivalence ratio of the stratified mixture in the spark gap. Adding a pre-chamber nozzle that can accelerate fuel into the pre-chamber creates a high-velocity flow into the pre-chamber during the compression stroke, promoting mixing within the mixture and creating a homogeneous fuel mixture. Continuing this process throughout the compression stroke allows fuel to accumulate in the pre-chamber, creating an optimal equivalence ratio mixture for earlier fuel injection timing. The reduction in the local equivalence ratio facilitated by TJCCI ensures robust and powerful flame propagation within the pre-chamber, leading to reduced nitrogen oxide emissions.

[0089] While only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without substantially departing from the invention, and all such modifications are therefore intended to be included within the scope of the present disclosure as defined in the following claims.

Claims

1. operating the engine within a first engine operating map region and a second engine operating map region by performing passive jet ignition combustion with a first stoichiometric fuel mixture and a first volume of residual gas; operating the engine within a mode transition region by performing passive jet ignition combustion with a second stoichiometric fuel mixture and a second volume of residual gas; the second volume of residual gas is controlled by ignition timing to meet a target engine load; and operating the engine within a third engine operating map region by implementing turbulent jet controlled compression ignition (TJCCI) with an ultra-lean fuel mixture and a first volume of cooled exhaust gas recirculation; operating the engine within the mode transition region; operating the engine within a fourth engine operating map region by performing passive jet ignition combustion with a third stoichiometric fuel mixture and a second volume of cooled exhaust gas recirculation; operating the engine within a fifth engine operating map region, the fifth engine operating map region being characterized by the engine being shut off; the engine having a cycle spanning two revolutions of a piston within the engine; The above cycle is an exhaust stroke, an intake stroke, a compression stroke, and an expansion stroke; a gas exchange top dead center piston position located between the exhaust stroke and the intake stroke; an ignition top dead center piston position located between the compression stroke and the expansion stroke; a bottom dead center piston position located between the intake stroke and the compression stroke and between the expansion stroke and the exhaust stroke; method.

2. Operating the engine within a first engine operating map region and a second engine map region comprises: During the exhaust stroke of the engine, performing a port fuel injection procedure; and Actuating an exhaust valve; During the intake stroke of the engine, actuating an intake valve at the beginning of said intake stroke; and performing a direct injection fueling sequence immediately after said gas exchange top dead center piston position; During the compression stroke of the engine, 2. The method of claim 1, further comprising providing a spark from a spark plug just prior to said firing top dead center piston position.

3. Operating the engine within a third engine operating map During the exhaust stroke of the engine, performing a port fuel injection procedure; and Actuating an exhaust valve; During the intake stroke of the engine, Actuating an intake valve; During the compression stroke of the engine, performing a direct injection fueling procedure at the beginning of said compression stroke; and 3. The method of claim 1 or 2, including providing a spark from a spark plug just prior to said firing top dead center piston position.

4. Operating the engine within a fourth engine operating map During the exhaust stroke of the engine, performing a port fuel injection procedure; and Actuating an exhaust valve; During the intake stroke of the engine, activating the intake valve during the intake stroke; and performing a direct injection fueling procedure during said intake stroke; During the compression stroke of the engine, A method according to any one of claims 1 to 3, including providing a spark from a spark plug just prior to said firing top dead centre piston position.

5. Operating the engine within the mode transition region During the exhaust stroke of the engine, performing a port fuel injection procedure; and Actuating an exhaust valve; During the intake stroke of the engine, actuating an intake valve at the beginning of said intake stroke; and performing a direct injection fueling sequence immediately after said gas exchange top dead center piston position; During the compression stroke of the engine, providing a first spark from a spark plug just prior to said firing top dead center piston position; During the expansion stroke of the engine, A method according to any one of claims 1 to 4, including providing a second spark from the spark plug immediately after the firing top dead centre piston position.

6. The method of any one of claims 1 to 5, wherein the second volume of cooled exhaust gas recirculation is greater than the first volume of cooled exhaust gas recirculation.

7. 7. The method of claim 1, further comprising transitioning from one engine operating map region to another engine operating map region based at least in part on a desired engine load and a desired engine speed provided to the computer processor by a user.

8. an engine block having a cylinder; a piston configured to move up and down within a main chamber of the cylinder; an auxiliary chamber in fluid communication with the main chamber; a fuel injector mounted to the engine block and in fluid communication with the main chamber; a computer system having a memory and a processor in communication with the piston, the exhaust valve, the intake valve, the one or more fuel injectors, and the spark plug, the processor comprising: operating the engine within a first engine operating map region and a second engine operating map region by performing passive jet ignition combustion with a first stoichiometric fuel mixture and a first volume of residual gas; operating the engine within a mode transition region by performing passive jet ignition combustion with a second stoichiometric fuel mixture and a second volume of residual gas; the second volume of residual gas is controlled by ignition timing to meet a target engine load; and operating the engine within a third engine operating map region by implementing turbulent jet controlled compression ignition (TJCCI) with an ultra-lean fuel mixture and a first volume of cooled exhaust gas recirculation; operating the engine within the mode transition region; operating the engine within a fourth engine operating map region by performing passive jet ignition combustion with a third stoichiometric fuel mixture and a second volume of cooled exhaust gas recirculation; operating the engine within a fifth engine operating map region, the fifth engine operating map region being characterized by the engine being shut off; Turbulent Jet Controlled Compression Ignition (TJCCI) engine system.

9. The engine has a cycle spanning two revolutions of the piston within the engine, the cycle comprising: an exhaust stroke, an intake stroke, a compression stroke, and an expansion stroke; a gas exchange top dead center piston position located between the exhaust stroke and the intake stroke; an ignition top dead center piston position located between the compression stroke and the expansion stroke; 9. The TJCCI engine system of claim 8, including a bottom dead center piston position located between said intake stroke and said compression stroke and between said expansion stroke and said exhaust stroke.

10. When the engine operates within the first and second engine operating map regions, the computer system: During the exhaust stroke of the engine, actuating a first fuel injector of the one or more fuel injectors in a port of the engine located proximate to the main chamber; and actuating the exhaust valve; During the intake stroke of the engine, actuating the intake valve at the beginning of the intake stroke; and activating a second fuel injector of the one or more fuel injectors disposed within the main chamber immediately after the gas exchange top dead center piston position; During the compression stroke of the engine, 10. The TJCCI engine system of claim 9, further configured to: actuate the spark plug located in the pre-chamber just prior to the firing top dead center piston position.

11. When the engine is operating within the third engine operating map region, the computer system: During the exhaust stroke of the engine, actuating a first fuel injector of the one or more fuel injectors in a port of the engine located proximate to the main chamber; and actuating the exhaust valve; During the intake stroke of the engine, actuating the intake valve; During the compression stroke of the engine, activating a second fuel injector of the one or more fuel injectors disposed within the main chamber at the beginning of the compression stroke; and 11. The TJCCI engine system of claim 9 or 10, further configured to: actuate the spark plug located in the pre-chamber just prior to the firing top dead center piston position.

12. When the engine is operating within the fourth engine operating map region, the computer system: During the exhaust stroke of the engine, actuating a first fuel injector of the one or more fuel injectors in a port of the engine located proximate to the main chamber; and actuating the exhaust valve; During the intake stroke of the engine, actuating the intake valve during the intake stroke; and activating a second fuel injector of the one or more fuel injectors disposed within the main chamber during the intake stroke; During the compression stroke of the engine, 12. The TJCCI system of claim 9, further configured to: actuate the spark plug located in the pre-chamber just prior to the firing top dead center piston position.

13. When the engine operates within the mode transition region, the computer system: During the exhaust stroke of the engine, actuating a first fuel injector of the one or more fuel injectors in a port of the engine located proximate to the main chamber; and actuating the exhaust valve; During the intake stroke of the engine, actuating the intake valve at the beginning of the intake stroke; and activating a second fuel injector of the one or more fuel injectors disposed within the main chamber immediately after the gas exchange top dead center piston position; During the compression stroke of the engine, activating the spark plug located in the pre-chamber immediately prior to the ignition top dead center piston position to generate a first spark; During the expansion stroke of the engine, and actuating the spark plug located in the pre-chamber to generate a second spark immediately after the ignition top dead center piston position.

14. 14. The TJCCI engine system of claim 9, wherein one of the one or more fuel injectors is disposed within the main chamber and configured to passively fuel the pre-chamber.

15. 15. The TJCCI engine system of any one of claims 8 to 14, wherein the first and second engine operating map regions are characterized by low engine speeds, low engine loads, or both.

16. 16. The TJCCI engine system of any one of claims 8 to 15, wherein the third engine operating map region is characterized by low to medium engine speeds and low to medium engine loads.

17. designing an engine to operate with passive jet ignition combustion under a first set of engine parameters, said passive jet ignition combustion comprising: injecting fuel from a fuel injector into a main chamber of the engine, whereby a quantity of the fuel is directed into a pre-chamber to provide a pre-chamber mixture in the pre-chamber and a main chamber mixture in the main chamber, the pre-chamber being adjacent to and in fluid communication with the main chamber; generating a spark in the pre-chamber to ignite the pre-chamber air-fuel mixture; and discharging the ignited pre-chamber air-fuel mixture from the pre-chamber into the main chamber to ignite the main chamber air-fuel mixture; the first set of engine parameters being: an engine speed ranging from a first minimum speed to a first maximum speed; an engine load ranging from a first minimum load to a first maximum load; under the first set of engine parameters, the ratio of fuel to air provided in the main and auxiliary chambers after the injection is stoichiometric; designing the engine to operate with passive jet ignition combustion under a second set of engine parameters, the second set of engine parameters comprising: the engine speed ranging from greater than the first maximum speed to a second maximum speed; the engine load ranging from the first minimum load to a second maximum load; designing the engine to change the ratio of fuel to air provided in the main and auxiliary chambers to an ultra-lean ratio when the engine is operated under a third set of engine parameters; under the third set of engine parameters, the engine speed is greater than the first maximum speed and the engine load is greater than the second maximum load; the ultra-lean ratio including more air than fuel. method.

18. providing an engine operating map defining a plurality of regions of engine operation, each region defining the ratio of fuel to air provided into the main and auxiliary chambers under different engine parameters, the plurality of regions comprising: a first region defining the stoichiometric ratio of fuel to air under the first set of engine parameters; a second region defining the stoichiometric ratio of fuel to air under the second set of engine parameters; a third region defining the ultra-lean ratio of fuel to air under the third set of engine parameters, the third set of engine parameters comprising: the engine speed ranging from greater than the first maximum speed to the second maximum speed; a third region further including the engine load ranging from a value greater than the second maximum load to a third maximum load; a fourth region defining the stoichiometric ratio of fuel to air under a fourth set of engine parameters, the fourth set of engine parameters comprising: the engine speed ranging from a value greater than the first maximum speed to a fourth maximum speed; a fourth region including the engine load ranging from greater than the third maximum load to the first maximum load.

19. 19. The method of claim 18, wherein the engine operating map further defines the third region as having a first amount of cooled EGR provided with the ultra-lean ratio of fuel to air and the fourth region as having a second amount of cooled EGR provided with the stoichiometric ratio of fuel to air, the second amount of cooled EGR being greater than the first amount.

20. 20. A method as claimed in any one of claims 17 to 19, wherein operating the engine under different engine parameters comprises causing the injections to occur at different times during a piston's cycle within the main chamber.

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