Internal combustion engine including multiple fuel injections external to the pre-combustion chamber

Abstract

The internal combustion engine (31) includes multiple fuel injections external to the pre-chamber (65). A further aspect provides an engine pre-chamber ignition system that uses a pre-assembled and / or removable cartridge (51) that includes an igniter (91) and a fresh air intake injector rather than a fuel intake injector directly attached thereto. Another aspect of the vehicle engine system includes a fuel injector (73) located external to the pre-chamber that provides an initial larger amount of fuel for combustion and a subsequent smaller amount of fuel for pre-chamber ignition.

Description

Detailed Description of the Invention

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 027,371, filed May 20, 2020, which is incorporated herein by reference.

[0002] (Background and Summary) This application relates generally to internal combustion engines, and more particularly to internal combustion engines having multiple fuel injections external to a pre-chamber.

[0003] It is known to experiment with internal combustion engines having a pre-combustion chamber separate from the main combustion chamber or piston cylinder. See, for example, U.S. Patent No. 10,161,296, entitled "Internal Combustion Engine," issued December 25, 2018, to co-inventors Schock et al., and International Publication No. WO 2019 / 027800, entitled "Diesel Engine with Turbulent Jet Ignition," co-invented by Schock et al., both of which are incorporated herein by reference. While these conventional turbulent jet ignition configurations represent a significant improvement in the industry, further improvements are desired to reduce parts and their associated costs and to package components more simply while achieving improved fuel efficiency.

[0004] In accordance with the present invention, an internal combustion engine is provided with multiple fuel injections external to the pre-chamber. In a further aspect, a pre-chamber ignition device is provided that employs a pre-assembled and / or removable cartridge that includes an igniter and an air valve rather than a fuel inlet injector directly attached thereto. In another aspect, an internal combustion engine system includes at least one opening extending between the pre-chamber and the main combustion chamber, with a tapered, enlarged inner surface at the end of the opening. In a further aspect of the vehicle engine system, a fuel injector located external to the pre-chamber provides an initial amount of fuel for the main combustion chamber and a subsequent smaller amount of fuel for pre-chamber ignition is provided. Methods of manufacturing and using an internal combustion engine employing multiple fuel injections external to the pre-chamber are also provided.

[0005] The present engine system has advantages over conventional systems. For example, the use of a single externally mounted fuel injector per pre-chamber / piston-cylinder combination reduces the cost and complexity of multiple fuel injectors and provides improved packaging space within the pre-chamber cartridge. As another example, the present pre-chamber cartridge, without a fuel injector directly attached thereto, allows for pre-assembly of components at a location other than where the cartridge is assembled to the engine cylinder head, reducing size, cost, internal passages, and assembly complexity. Furthermore, the present invention reduces engine weight and improves fuel economy. Also, the fastening of the present cartridge is faster and easier to assemble and access, while the present cartridge is more commercially practical to fit into various engine cylinder head configurations. Additional advantageous features and characteristics of the present system and method will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a top perspective view showing the engine arrangement that uses a pre-chamber cartridge secured to the engine cylinder head.

[0007] FIG. 2 is a cross-sectional view of the device taken along line 2-2 of FIG.

[0008] FIG. 3 is a top perspective view showing the pre-combustion chamber cartridge and camshaft of the device with the engine cylinder head removed.

[0009] 4-9 are schematic side views showing the pre-chamber cartridge and main piston cylinder of the device under different operating conditions.

[0010] FIG. 10 is a schematic enlarged side view showing the open ports used with the pre-chamber cartridge of the present device.

[0011] FIG. 11 is a graph showing the fuel injection, ignition and combustion timing of the present device.

[0012] (Detailed explanation) 1-3, an automotive internal combustion engine 31 includes an engine block 33 and a cylinder head 35 attached thereto. A main drive piston 37 operably advances and retracts within a main piston-cylinder cavity 39 to drive a connecting rod 41 spanning a pin 43 of the piston 37 and a crankshaft 45. The cylinder head 35 further includes an intake passage 47, an exhaust passage 49, and a pre-combustion chamber cartridge 51 of a turbulent jet ignition system. The main combustion chamber 53 is located directly below the turbulent jet ignition cartridge 51 and is partially disposed above the main piston 37 within the cylinder cavity 39 and cylinder head 35. The cylinder head 35 optionally includes a removable cover 55, and a camshaft 57 is rotatably disposed within the cylinder head. In some configurations, the camshaft may be disposed with the cylinder block.

[0013] 4 and 10, the turbulent jet ignition cartridge 51 includes a body 61 and a cup-shaped and internally concave pre-chamber housing 63. The pre-chamber housing 63, in combination with a cylindrical nose 64 projecting centrally and coaxially therefrom, internally defines a pre-chamber cavity or pre-chamber 65 therein. The cartridge 51 also has a laterally projecting flange 66 that is secured to the upper surface of the cylinder head 35 via threaded fasteners, optional dowel pins, and laterally elongated braces 69, or by other structures and fasteners.

[0014] At least one, and more preferably between three and ten, elongated openings 71 are always open, connecting the nose 64 of the pre-combustion chamber 65 to the main combustion chamber 53. Each opening has a constant diameter along its primary tubular section 72. However, at least the opening 71 closest to the fuel injector 73 has an enlarged and convergent port 75, preferably frusto-conical, at the distal end of the primary tubular section 72 that interacts with the main piston cylinder 53. Preferably, the distal ends of the other openings 71 do not have an enlarged port, although such a port may optionally be included for multiple openings. While only an obliquely oriented opening 71 is provided in the example shown in FIG. 4, it is alternatively contemplated that one or more centerline openings may be included, depending on the desired fuel and air mixture for a particular engine and fuel type.

[0015] The turbulent jet ignition cartridge 51 includes an igniter 91, such as a spark plug, glow plug, or the like. The igniter 91 has a central portion removably secured within the elongated opening in the body 61 and a distal end disposed within the pre-combustion chamber 65 to provide a spark or other thermal ignition source for the fuel-rich fuel-air mixture therein. An optional pre-combustion chamber pressure transducer or indicator may be part of the igniter 91 or may be in communication with it through the pre-combustion chamber housing 63. It is also contemplated that an optional electrical resistance heater may be disposed internally within the cartridge 51, within the pre-combustion chamber 65, or upstream of the valve 125.

[0016] As can be seen in Figures 3-5 and 10, the pre-chamber intake valve 111 has a central portion disposed within another elongated opening through the body 61 of the cartridge 51, with an air valve seat 115 at its distal end disposed within the pre-chamber 65. Furthermore, the proximal end portion of the intake valve 111 is disposed within a generally cylindrical collar 112 that integrally upstands from the body 61. The intake valve 111 includes a spirally wound spring and a retaining cap that holds the spring on a longitudinally elongated shaft 125. The intake valve 111 is preferably a poppet valve type that is actuated by a rocker arm 126 driven by the camshaft 57, or may alternatively be actuated by a hydraulic, electromagnetic, or piezoelectric actuator.

[0017] The pre-chamber intake valve 111 is separate from the main piston chamber intake valve 127, which is shown as a poppet arrangement, and a cam-actuated poppet-style exhaust valve 131 is located at the top opposite side of the main piston chamber 53. Alternatively, either of the poppet valves may instead be pin-valves or rotary valves.

[0018] The ambient air conduit 141 is externally connected to the top surface of the cartridge 51 by a threaded fitting. One or more passages within the cartridge body convey ambient air from the conduit 141 to the pre-chamber intake valve 111. An in-line heater 147 is positioned adjacent to the air conduit 141. The heater 147 can be primarily an external heater (as shown) or primarily an internal heater. In a variant, it is envisioned that the heater comprises one or more electrical resistance wires or coils that contact and heat the conduit 141 and / or aluminum metal fins or structures protruding therefrom that contact the ambient air flowing therethrough. In an internal heater version, for example, an open-cell metal foam with highly interconnected porosity and circuit paths is inside an enlarged cylinder aligned coaxially with the conduit 141, and the foam structure is heated by a resistance coil. Such heat transfer foams are disclosed in U.S. Patent Application Publication No. 2005 / 0092181, entitled "Active Filtration of Airborne Contaminants Employing Heated Porous Resistance—Heated Filters," by Shih et al., which is incorporated herein by reference. The heater 147 and pre-chamber combination heat incoming fresh air during initial engine start-up and warm-up, after which the heater is deactivated. Alternatively, a separate parallel bypass air conduit can be fed directly to the main body and air intake valve, with an air flow valve switching between the two air conduits depending on whether heating is desired, as automatically controlled by a programmable pre-chamber or engine controller. Alternatively, the heater may use a resistive membrane within the main body or air conduit rather than a wire or coil. This heater and pre-chamber system offers advantages over heaters associated only with the main piston cylinder: easier installation, easier packaging, and more efficient and effective in heating fresh air prior to combustion.

[0019] The fuel injector 73 preferably has an elongated, generally cylindrical tip and is located in a laterally open bore in the side of the main piston cylinder 53 adjacent the main intake valve 127. Alternatively, the fuel injector 73 can be located elsewhere in the piston cylinder outside of the pre-chamber. The extension and fuel injection direction of the fuel injector 75 are generally perpendicular to the central axis 78 of the pre-chamber 65, which is coaxial with the advance and retreat axis of the piston 37. Alternatively, the fuel injector direction may be within 80-110° of the pre-chamber 65 centerline. It is noteworthy that only a single fuel injector is used for each piston cylinder 53 and pre-chamber 65 configuration; no fuel injectors are located within the pre-chamber 65 for this system. Thus, if the engine is a four-cylinder engine, there is one fuel injector associated with each of the four piston cylinders, either directly located in one of the four pre-chambers or without a direct-injecting fuel injector.

[0020] The cartridge 51 is preferably manufactured separately from the cylinder head 35. The outside of the cartridge is machined from aluminum or steel, and the passages are machined internally. If the body is cast or machined as two separate pieces, the cartridge body is then furnace brazed or diffusion welded. Alternatively, the cartridge body and / or pre-chamber may be made from ceramic or other low-thermal-conductivity materials. Tapered and annular seals, preferably made from copper, internally contact the pre-chamber housing and, when screwed together, seal between the seals and threaded fittings at the bottom end of the body 51. The igniter, fuel injector, and air valve are then assembled to the body, for example, by threading or otherwise securing the components.

[0021] The function of this system will now be described with reference to FIGS. 4-9. The pre-chamber intake valve 111 advantageously serves a dual synergistic purpose: supplying air into the pre-chamber before and / or after combustion and supplying additional airflow into the pre-chamber to purge combustion residues. Thus, at the beginning of a cycle when the associated crankshaft is at its rotational position from 0-180° TDC, the pre-chamber air valve seat 115 opens, allowing fresh air 149 to push out and purge any residual combustion particulates remaining in the pre-chamber 65 from the previous cycle. This creates greater air pressure in the pre-chamber than in the main combustion chamber 53 as the piston 37 simultaneously advances away from the pre-chamber 65. Shortly thereafter, as seen in FIGS. 4 and 5, with the associated crankshaft at its rotational position from 60-200° TDC, the fuel injector 73 releases a first spray of liquid fuel 151 approximately perpendicular to or within 80-100° of the pre-chamber and piston axis 78 (see FIG. 2). At the same time, the main air valve 127 opens, allowing incoming air 153 to enter the main combustion chamber 53 and help mix the injected fuel 151 outside the pre-chamber. The air pressure in the pre-chamber 65 is higher than the pressure in the main combustion chamber 53 during this period of operation, thereby essentially preventing fuel from entering the opening 71.

[0022] 6 and 7 show 200-235° TDC, where the fuel injectors 73 are deactivated and stopped, and the piston 37 is on its retraction and compression motion toward the pre-chamber 65. The main air valve 127 is closed in this operating position range. This forces fuel 151 into the pre-chamber 65 because piston compression creates greater pressure in the main combustion chamber 53 than exists in the pre-chamber cavity, even with fresh air entering the pre-chamber 65 from the pre-chamber air valve 111. The air and fuel turbulently swirl and mix within the pre-chamber in this operating condition.

[0023] Next, FIG. 8 shows a typical TDC temperature range of 240-320° where air valves 111 and 127 are closed and piston 37 continues its compression retraction. Fuel injector 73 now ejects a second mist or spray of liquid fuel 151 toward the longitudinal centerline between pre-chamber 65 and the combustion surface of piston 37 into main combustion chamber 53. This second fuel quantity in FIG. 8 is less than the first fuel quantity in FIGS. 4 and 5. This second ejection of fuel causes a rich fuel-air mixture to enter partially into the pre-chamber through opening 71 and mix with the air and fuel already in main combustion chamber 53.

[0024] 9 is the 345-350° TDC position where the fuel injectors are deactivated, the air valve is closed, and the igniter 91 is activated in the pre-chamber 65. This causes the fuel 151 to ignite and burn within the pre-chamber 65. This pre-combustion 155 is then discharged out of the pre-chamber into the main combustion chamber 53 through opening 71, which completely ignites the fuel 151 located within the main piston cylinder. The main combustion occurring within the main combustion chamber 53 serves to advance the piston away from the pre-chamber.

[0025] Figure 11 illustrates the timing used in two versions of the device. The first fuel injection version 201 (shown in solid lines in the top half) turns on the fuel injector for a continuous period for the first release. Fuel injection is then turned off. The same fuel injector is then turned on again for a second release of fuel for a much shorter period after the pressure in the main chamber exceeds the pressure in the pre-chamber at time 205. The pre-chamber pressure is shown by line 207, the main chamber pressure is shown by line 209, and P atm is atmospheric pressure. Ignition then occurs in the pre-combustion chamber at point 211, and main piston combustion occurs shortly thereafter at point 213, caused by pre-combustion particles flowing from the pre-combustion chamber through an opening into the main combustion chamber.

[0026] A second variation is shown in dashed line at 203. In this configuration, the initial fuel release is actually a series of multiple rapid initial on-and-off fuel releases that occur while the pre-chamber pressure exceeds the main chamber pressure. This approach allows for the first series of fuel releases and the single fuel release after point 205 to each be generally equal in volume, but overall provides a significantly greater total volume and timing before compared to after point 205.

[0027] The present apparatus and method can be used with either gasoline, petrol, or heavy diesel fuel. Nevertheless, diesel fuel is expected to be ideally suited for this external fuel injection into the pre-chamber because diesel fuel mist is finer and has smaller droplet size compared to gasoline. As such, the finer diesel mist will be more completely forced back from the main piston cylinder into the pre-chamber and more thoroughly mixed with fresh air from the pre-chamber air valve.

[0028] While various features of the present invention have been disclosed, it should be understood that other variations can be used. For example, different air valve actuator configurations and locations can be employed, but various advantages of the present system may not be realized. As another example, the cartridge flange can have a different shape than that shown, but certain benefits may not be achieved. Furthermore, alternative shapes, numbers, and angles of passages, as well as conduits, openings, and ports, can be provided within the cartridge, although certain advantages may not be achieved. Alternatively, variations using fuel-air mixtures and combustion injection timing can be employed, although performance may be compromised. For example, various alternative liquid or gaseous fuels can be used instead of gasoline. Furthermore, while the cartridge and pre-chamber configurations currently illustrated are best suited for overhead cam engines, differently shaped and sized cartridges and pre-chambers may be employed for engines with different configurations, such as cam-in-block engines. In another variation, if the fuel injector and pre-chamber intake valve are combined, only two openings (one each) may be required within the pre-chamber cartridge. Variations should not be considered a departure from the disclosure, and all such modifications are intended to be within the scope and spirit of the present invention. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a top perspective view of the present engine arrangement utilizing a pre-chamber cartridge secured to the engine cylinder head. [Figure 2] 2 is a cross-sectional view of the device taken along line 2-2 of FIG. 1. [Figure 3] FIG. 1 is a top perspective view showing the pre-chamber cartridge and camshaft of the device with the engine cylinder head removed. [Figure 4] 1A-1C are schematic side views showing the pre-chamber cartridge and main piston cylinder of the device at different operating conditions. [Figure 5]1A-1C are schematic side views showing the pre-chamber cartridge and main piston cylinder of the device at different operating conditions. [Figure 6] 1A-1C are schematic side views showing the pre-chamber cartridge and main piston cylinder of the device at different operating conditions. [Figure 7] 1A-1C are schematic side views showing the pre-chamber cartridge and main piston cylinder of the device at different operating conditions. [Figure 8] 1A-1C are schematic side views showing the pre-chamber cartridge and main piston cylinder of the device at different operating conditions. [Figure 9] 1A-1C are schematic side views showing the pre-chamber cartridge and main piston cylinder of the device at different operating conditions. [Figure 10] FIG. 10 is a schematic enlarged side view showing the open ports used with the pre-chamber cartridge of the present device. [Figure 11] 2 is a graph showing fuel injection, ignition and combustion timing of the present device.

Claims

1. a pre-combustion chamber including a pre-combustion chamber cavity and at least one combustion exit opening; an igniter having a distal end within or directly adjacent to the pre-chamber cavity; a pre-chamber intake valve having a portion disposed within or adjacent to the pre-chamber cavity; a main piston cylinder containing a main combustion chamber; a fuel injector located external to the pre-chamber cavity, the fuel injector including an injection tip located within the main combustion chamber and spaced apart from the pre-chamber; the fuel injector operably discharges a first quantity of liquid fuel into the main combustion chamber, the first quantity of liquid fuel being forced into the at least one combustion exit opening for subsequent pre-combustion by the igniter in the pre-combustion chamber cavity, the fuel injector being the sole source of the liquid fuel into the pre-combustion chamber cavity; the fuel injector operably discharges a second amount of the liquid fuel into the main combustion chamber, the second amount being less than the first amount of the liquid fuel for combustion in the main combustion chamber, and at least the second amount of the liquid fuel is ignited by pre-combustion occurring in the pre-combustion chamber cavity.

2. 10. The apparatus of claim 1, wherein the pre-chamber is part of a cartridge, the igniter, the pre-chamber intake valve, and the pre-chamber cavity are pre-assembled into a body of the cartridge, and the pre-assembled cartridge is thereafter removably attached to an engine cylinder head.

3. 3. The apparatus of claim 2, wherein the cartridge does not have a fuel injector attached thereto and the fuel is not injected directly into the pre-chamber cavity other than indirectly through the at least one combustion exit opening.

4. 10. The apparatus of claim 1, wherein the at least one combustion exit opening includes a narrowed portion having a uniformly circular inner diameter and an enlarged port at an end of the combustion exit opening, the port having an enlarged inner dimension that is larger than the narrowed portion.

5. 5. The apparatus of claim 4, wherein the interior surface of the port is frustoconical and flares toward the main combustion chamber.

6. 5. The apparatus of claim 4, wherein only one of a plurality of openings extending from the pre-combustion chamber to the main combustion chamber has the enlarged port, and the opening having the port is located closest to the fuel injector.

7. the second amount of fuel is 3-15% of the first amount of fuel; the first amount of fuel is injected before a point at which the pressure in the main combustion chamber changes from less than the pressure in the pre-combustion chamber to greater than the pressure in the pre-combustion chamber; The apparatus of claim 1 , wherein the second amount of fuel is injected after the change point.

8. 10. The apparatus of claim 1, wherein the pre-chamber intake valve releases fresh air into the pre-chamber cavity during each cycle after combustion during a cycle therein to purge burned particles within the pre-chamber cavity.

9. the first quantity of fuel is released over a longer period of time than the second quantity of fuel; 10. The apparatus of claim 1, wherein the fuel and air mixture in the pre-chamber is fuel-rich prior to ignition.

10. a piston that linearly advances and retracts along a longitudinal axis within the main piston cylinder; The pre-chamber comprises a concave curved cup; a cylindrical nose extending centrally therefrom toward said piston and coaxial with said longitudinal axis of said piston; a maximum lateral inner diameter of the concave curved cup is greater than an inner diameter of the nose; The apparatus of claim 1 , wherein the at least one combustion exit opening comprises at least four combustion exit openings extending through the nose.

11. 1. An engine system comprising a pre-assembled cartridge, The cartridge is a body including a plurality of body openings therein; a pre-combustion chamber coupled to the body, the pre-combustion chamber including a pre-combustion chamber cavity and at least one combustion exit opening; an igniter disposed in a first of the plurality of body openings; a pre-chamber intake valve disposed in a third of the plurality of body openings; The engine device is a main piston cylinder; a piston that linearly advances and retracts along a longitudinal axis within the main piston cylinder; a single fuel injector disposed external to the pre-chamber cavity and associated with the main piston cylinder and the pre-chamber, the fuel injector including an injection tip disposed within the main piston cylinder; a main air intake valve associated with an air inlet in the main piston cylinder outside the pre-combustion chamber; the pre-chamber including a concave cup coaxial with the longitudinal axis of the piston; the fuel injector operably discharges into the main piston cylinder a first quantity of liquid fuel that is homogeneously mixed in a main combustion cavity, and during a later stage of compression, a portion of the first quantity of liquid fuel is compressed into the pre-chamber cavity; the fuel injector operatively discharges a later quantity of the liquid fuel into the main piston cylinder that is less than the first quantity of the liquid fuel for combustion to enrich the fuel-air mixture in the pre-combustion chamber cavity; The engine system wherein the latter quantity of the liquid fuel is ignited by pre-combustion occurring within the pre-combustion chamber cavity.

12. the pre-combustion chamber being part of a cartridge; the igniter, the pre-chamber intake valve, and the pre-chamber cavity are pre-assembled to the cartridge body; 12. The apparatus of claim 11, wherein the pre-assembled cartridge is then removably attached to an engine cylinder head.

13. 13. The apparatus of claim 12, wherein the cartridge does not have a fuel injector attached thereto and fuel is not injected directly into the pre-chamber cavity other than indirectly through the at least one combustion exit opening.

14. The apparatus of claim 11, wherein the later amount of fuel is 3 to 15% of the first amount of pre-injected fuel.

15. An engine assembly including a pre-assembled cartridge, comprising: The cartridge is a body including a plurality of body openings therein; a pre-combustion chamber coupled to the body, the pre-combustion chamber including a pre-combustion chamber cavity and at least one combustion exit opening; an igniter disposed in a first of the plurality of body openings; a pre-chamber intake valve disposed in a third of the plurality of body openings; The engine device is a main piston cylinder; a piston that linearly advances and retracts along a longitudinal axis within the main piston cylinder; a single fuel injector disposed external to the pre-chamber cavity and associated with the main piston cylinder and the pre-chamber, the fuel injector including an injection tip disposed within the main piston cylinder; a main air intake valve associated with an air inlet in the main piston cylinder outside the pre-combustion chamber; the pre-chamber including a concave cup coaxial with the longitudinal axis of the piston; The at least one combustion exit opening is 1. An engine arrangement comprising: an elongated portion having a uniformly circular inner diameter; and an enlarged port at an end of said at least one combustion exit opening, said port having an enlarged inner dimension greater than said elongated portion.

16. An engine assembly including a pre-assembled cartridge, comprising: The cartridge is a body including a plurality of body openings therein; a pre-combustion chamber coupled to the body, the pre-combustion chamber including a pre-combustion chamber cavity and at least one combustion exit opening; an igniter disposed in a first of the plurality of body openings; a pre-chamber intake valve disposed in a third of the plurality of body openings; The engine device is a main piston cylinder; a piston that linearly advances and retracts along a longitudinal axis within the main piston cylinder; a single fuel injector disposed external to the pre-chamber cavity and associated with the main piston cylinder and the pre-chamber, the fuel injector including an injection tip disposed within the main piston cylinder; a main air intake valve associated with an air inlet in the main piston cylinder outside the pre-combustion chamber; the pre-chamber including a concave cup coaxial with the longitudinal axis of the piston; the pre-combustion chamber intake valve discharges fresh air into the pre-combustion chamber cavity after an exhaust stroke during each cycle to purge burned particles in the pre-combustion chamber cavity; the second amount of fuel is 3 to 15% of the first amount of fuel, the first amount of fuel is injected from the fuel injector before a change point where a pressure in a main combustion cavity changes from below a pressure exceeding a pressure in a pre-combustion cavity, and the second amount of fuel is injected after the change point.

17. An engine assembly including a pre-assembled cartridge, comprising: The cartridge is a body including a plurality of body openings therein; a pre-combustion chamber coupled to the body, the pre-combustion chamber including a pre-combustion chamber cavity and at least one combustion exit opening; an igniter disposed in a first of the plurality of body openings; a pre-chamber intake valve disposed in a third of the plurality of body openings; The engine device is a main piston cylinder; a piston that linearly advances and retracts along a longitudinal axis within the main piston cylinder; a single fuel injector disposed external to the pre-chamber cavity and associated with the main piston cylinder and the pre-chamber, the fuel injector including an injection tip disposed within the main piston cylinder; a main air intake valve associated with an air inlet in the main piston cylinder outside the pre-combustion chamber; the pre-chamber including a concave cup coaxial with the longitudinal axis of the piston; an engine cylinder head; a camshaft, the cartridge is removably mounted in a valley of the engine cylinder head between the camshafts rotatable about a parallel axis, the axis being substantially perpendicular to a longitudinal centerline of the pre-chamber; the release of a first quantity of fuel by the fuel injector for use in the main piston cylinder is for a longer time than the release of a final quantity of fuel by the fuel injector for use in enriching the pre-chamber; The engine system wherein the mixture of fuel and air in the pre-combustion chamber is fuel-rich.

18. A method of using a vehicle engine, comprising: a first step of injecting a first amount of fuel into a main combustion chamber from a fuel injector between a surface of a piston and a pre-combustion chamber while the piston advances away from the pre-combustion chamber while a pre-combustion chamber air valve allows air to flow directly into the pre-combustion chamber; a second step, after the first step, of forcing at least a portion of the first quantity of fuel from the main combustion chamber into the pre-chamber while the piston is retracting toward the pre-chamber; a third step, after the second step, injecting a subsequent amount of fuel from the fuel injector into the main combustion chamber for combustion, the subsequent amount being less than the first amount of fuel, while the piston is retracted toward the pre-combustion chamber and the pre-combustion chamber air valve and the main air valve are closed; a fourth step, after said third step, of igniting said fuel in said pre-chamber which subsequently causes combustion of said fuel in said main combustion chamber.

19. The method of claim 18, further comprising the step of purging combustion particles from the pre-combustion chamber to the main combustion chamber by allowing air to flow directly into the pre-combustion chamber through the pre-combustion chamber air valve; ignition of the fuel in the pre-chamber is caused by an igniter having a tip disposed within a curved cup of the pre-chamber; the fuel injector discharges the fuel toward a central axis of the pre-combustion chamber and the piston and in a direction within 80-120 degrees offset from the central axis; the fuel injector is external to the pre-combustion chamber and includes a main inlet air valve disposed between a fuel discharge end of the fuel injector and the pre-combustion chamber; The method of claim 18 , wherein the injection of the later amount of fuel is no more than 15% of the injection of the first amount of fuel.

20. The injection of the first quantity of fuel further comprises a series of rapid injections of the fuel occurring while the pressure in the pre-combustion chamber exceeds the pressure in the main combustion chamber; 20. The method of claim 18, wherein injecting the later quantity of fuel occurs while the pressure in the main combustion chamber exceeds the pressure in the pre-combustion chamber.

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