WO2023021531A1

WO2023021531A1 - Pre-chamber ignition unit for an internal combustion engine

Info

Publication number: WO2023021531A1
Application number: PCT/IN2022/050749
Authority: WO
Inventors: A Ramesh; Mayank MITTAL; Prajwal R; Jubin V JOSE; Gutti Gnanakotaiah; Kuduva Shanthulal Vishnukumar
Original assignee: INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT Madras); Tvs Motor Company Limited
Priority date: 2021-08-19
Filing date: 2022-08-18
Publication date: 2023-02-23

Abstract

A pre-chamber ignition unit (104) comprises at least one injector holder (107) being connected to at least one fuel injector (106), a pre chamber top (108), a pre chamber bottom (110) at least one spark plug (112), being connected to the pre chamber top (108). A pre-chamber cavity (114) being formed between ends of the pre chamber top (108) and the pre chamber bottom (110). Further, at least one orifice (116, 116'), being disposed at a bottom portion (118) of the pre chamber bottom (110). Furthermore, the pre chamber bottom (110) comprises an outer portion, such that the outer portion being detachably attached to an internal combustion engine (102) of the vehicle (100). Moreover, at least a portion of the pre chamber bottom (110) comprising the at least one orifice (116, 116') being disposed within the internal combustion engine (102) of the vehicle (100).

Description

TITLE OF THE INVENTION

PRE CHAMBER IGNITION UNIT FOR AN INTERNAL COMBUSTION ENGINE

FIELD OF THE INVENTION

The present disclosure relates generally to Internal Combustion (IC) engine of a vehicle and more specifically to a pre-chamber ignition unit for an Internal Combustion (IC) engine of a vehicle.

BACKGROUND OF THE INVENTION

In order to improve efficiency and exhaust performance of an Internal Combustion (IC) engine of a vehicle, a lean air/fiiel mixture may be provided to the IC engine when the same is operating at a relatively low engine load. The IC engine includes a plurality of cylinders formed by an IC engine block. Each cylinder is capped by a cylinder head, and the cylinders and cylinder head together form a plurality of ignition chambers. Each ignition chamber includes a piston disposed therein. The IC engine may be supplied with fuel by a plurality of fuel injectors. Each ignition chamber is configured to combust a mixture of air-fuel mixture. The ignition chambers receive air via an inlet port including one or more intake ports coupled to each ignition chamber. Each intake inlet includes an intake valve disposed therein. The injected air- fuel mixture may mix and be combusted within each combustion chamber. The resulting gases from combustion may then exit each ignition chamber via an exhaust port including one or more exhaust outlet coupled to each combustion chamber, with separate exhaust valves disposed within each exhaust outlet. The fuel of the IC engine may be in liquid state such as gasoline, diesel, or the like or in gaseous state like Compressed Natural Gas (CNG), Light Petroleum Gas (LPG), or the like. Conventionally pre-chamber ignition unit have been used to enhance ignition energy of the IC engines mainly in large gas engines used for power generation. Research studies have also tested their suitability for automotive IC engines and have shown potential benefits, but they have not been commercialized widely. In the pre-chambers main chamber is connected to one or more orifices. The charge inside the convention pre-chamber ignition unit is maintained slightly rich. This rich charge is ignited by a spark plug inside the convention pre-chamber ignition unit. The combustion inside the convention pre-chamber ignition unit generates heat energy and these hot burning gases enter the ignition chamber of the IC engine through the orifices and ignite the fuel inside the ignition chamber of the IC engine. The energy released by the convention pre-chamber ignition unit is much higher than energy released by the spark ignition system. Convention pre-chamber ignition unit also significantly improves the combustion rates inside the ignition chamber when multiple orifices are used due to distributed ignition inside the ignition chamber.

Most convention pre-chamber ignition unit were developed for large power generation IC engines or high displacement automotive IC engines where there is sufficient space for mounting the convention pre-chamber ignition unit on the IC engine cylinder head. However, problem arises when we try to place the convention pre-chamber ignition unit on a small automotive IC engine, such as IC engine of volume 200cc due to limited space on cylinder head. Due to the small IC engine displacement volume, the volume of the pre-chamber ignition unit also has to be very small which is a very big problem. Thus, pre-chamber ignition unit for small IC engines can even be as small such as 1 cc which further makes mounting the injector and sparkplug a challenging task. Also, due to the limited space on the cylinder head and the provision of valves and overhead camshaft/s that occupy the central region of the cylinder head, the pre-chamber ignition unit has to be oriented towards one side of the combustion chamber in small automotive IC engines. This orientation is not ideal for the pre-chamber ignition unit as the flames have to travel larger distance to consume the charge. Thus, the orifices of the convention pre-chamber ignition unit have to be modified to optimize the ignition and combustion. Thus, there remains a significant unmet need for the unique apparatuses, methods, systems and techniques disclosed herein.

The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

According to one of the embodiments, a pre-chamber ignition unit comprises at least one injector holder is connected to at least one fuel injector, a pre chamber top, a pre chamber bottom, at least one spark plug is connected to the pre chamber top. Further, the pre-chamber ignition unit also comprises a pre-chamber cavity which is formed between ends of the pre chamber top and the pre chamber bottom and at least one orifice being disposed at a bottom portion of the pre chamber bottom. Furthermore, the pre chamber bottom comprises an outer portion, such that the outer portion being detachably attached to an internal combustion engine. Moreover, at least a portion of the pre chamber bottom comprising the at least one orifice being disposed within the internal combustion engine. According to one of the embodiments, an internal combustion engine of a vehicle comprising at least one cylinder head being disposed above a cylinder block and the cylinder block being disposed above a crankcase, an ignition chamber being formed by the at least one cylinder head, at least one inlet port for inputting air-fuel mixture in the ignition chamber, at least one exhaust port for exhaust of gasses from the ignition chamber and at least one pre-chamber ignition unit disposed over one side of the at least one cylinder head. The pre-chamber ignition unit comprises at least one injector holder which is connected to at least one corresponding fuel injector. The pre-chamber ignition unit also comprises a pre chamber top, a pre chamber bottom, at least one corresponding spark plug is connected to the pre chamber top. Further, the pre-chamber ignition unit also comprises a pre-chamber cavity which is formed between ends of the pre chamber top and the pre chamber bottom and at least one corresponding orifice being disposed at a bottom portion of the pre chamber bottom. Furthermore, the pre chamber bottom comprises an outer portion, such that the outer portion being detachably attached to an internal combustion engine. Moreover, at least a portion of the pre chamber bottom comprising the at least one orifice being disposed within the internal combustion engine.

According to one of the embodiments, a method of operating an internal combustion engine with at least one pre-chamber ignition unit the method comprising step of injecting, by at least one corresponding fuel injector, a compressed air-fuel mixture into a pre-chamber cavity of the at least one corresponding pre-chamber ignition unit. Further, igniting, by corresponding at least one corresponding spark plug, the injected and the compressed air-fuel mixture. Furthermore, transferring, the ignited air-fuel mixture from a pre-chamber cavity to at least one corresponding ignition chamber of the internal combustion engine via at least one corresponding orifice. The present invention relates to overcoming the problems of the related to pre-chamber ignition unit of an internal combustion engine and providing a new type of pre-chamber ignition unit having a new orifice configuration which is a combination of radial and axial orifices. More specifically, in the present disclosure a new orifice configuration is disclosed which is a combination of radial and axial orifices. Further, on doing the research to validate the proposed configuration of orifices, the same showed that this leads to better ignition and combustion in small sized internal combustion engine of the automobiles with pre-chamber ignition unit on one side of the cylinder head. Further, a new method of mounting the direct injector on the prechamber ignition unit is proposed in this invention. This method allows for easy mounting, adjusting and removal of the direct injector from the pre-chamber ignition unit when compared with the conventional pre-chambers ignition unit that use interference fit between the injector and the pre-chamber body.

According to one of the embodiments, it is an object of the present invention to provide an engine, which is compact, efficient and light in weight.

The present invention is described with reference to an exemplary embodiment of an engine. Such engine can be installed in a two or three or multi wheeled vehicle. The same numbers are used throughout the drawings to reference like features and components. Further, the inventive features of the invention are set forth in the claims of the present application.

BRIEF DESCRIPTION OF FIGURES:

The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate preferred embodiments of the invention, and together with the general description given above and the detailed description given below, serve to explain features of the invention.

Figure 1 illustrates a pre-chamber ignition unit as per one of the embodiments of the present disclosure.

Figures 2A and 2B illustrates front view and bottom view respectively of orifice configuration of the pre-chamber ignition unit as per one of the embodiments of the present disclosure.

Figure 3 illustrates a sectional view showing a connection of a spray plume passage and a prechamber cavity of the pre-chamber ignition unit as per one of the embodiments of the present disclosure.

Figures 4A and 4B illustrates model sectional view of the pre-chamber unit connected with an internal combustion engine of a vehicle as per one of the embodiments of the present disclosure.

Figure 5 illustrate pre-chamber unit mounted at a center of an engine cylinder head in Dual Overhead Camshaft (DOHC) configuration as per one of the embodiments of the present disclosure.

Figure 6 - 14 illustrate working conditions comparison of the pre chamber ignition unit of the small volumed automobile IC engine with respect to the conventional small volumed automobile IC engine in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION

Exemplary embodiments detailing features of an Internal Combustion (IC) engine in a vehicle, in accordance with the present subject matter will be described hereunder with reference to the accompanying drawings. Various aspects of different embodiments of the present invention will become discernible from the following description set out hereunder. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the present subject matter. Further, it is to be noted that terms “upper”, “lower”, “right”, “left”, “front”, “forward”, “rearward”, “downward”, “upward”, “top”, “bottom” and like terms are used herein based on the illustrated state or in a standing state of the vehicle with a driver riding thereon. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification.

The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar elements. While embodiments may be described, modifications, adaptations, and other implementations are possible. For example, substitutions, additions, or modifications may be made to the elements illustrated in the drawings, and the methods described herein may be modified by substituting, reordering, or adding stages to the disclosed methods. Accordingly, the following detailed description does not limit the claimed subject matter. Instead, the proper scope of the claimed subject matter is defined by the appended claims. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, disposed, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer those two elements are directly connected to each other.

It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.

According to a preferred embodiment, an Internal Combustion (IC) engine is described herein that operates in four cycles. However, the scope of the present subject matter is not limited to only IC engines but is applicable to all kinds of engine or any power generating unit. The IC engine is installed in a vehicle. It is pertinent to note that the IC engine may be mounted in vehicles in different arrangements such as in transverse and longitudinal fashion. The scope of the present invention might be applicable to any power generating unit or engines in any type of vehicle such as two-wheeled vehicles, three-wheeled vehicles, four-wheeled vehicles and the like. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essential part has been omitted at suitable places.

Typically, an IC engine comprises a cylinder block having a cylinder bore, a piston reciprocating in the cylinder bore, a cylinder head located above the cylinder block and a ignition chamber formed between the cylinder head, a top surface of the piston, and walls of the cylinder bore. Air-fuel mixture is ignited in the ignition chamber which expands imparting reciprocating motion to the piston which is converted to rotary motion of a crankshaft through a connecting rod. Further, the motion from the crankshaft is transmitted to wheels of the vehicle through a transmission system. Typically, IC engines have a lot of reciprocating and moving parts. It is essential that such moving parts remain well lubricated for its operation under all conditions of operation. Additionally, it is essential to perform cooling to critical parts of the IC engine. Hence, an effective lubrication and cooling system which is robust is essential in all IC engines. A good lubrication and cooling system of the overheated engine oil ensures long life of the IC engine, maximizes power output, increases efficiency, and improves reliability.

In small bore spark-ignition engines (SI engines), use of lean and ultra-lean combustion is configured to enhance efficiency of the SI engines and reduce engine-out Nitrogen Oxide (NOx) emissions. The SI engines is configured to lower the pumping work as higher throttle opening can be used for the same Brake Mean Effective Pressure (BMEP). The SI engines also reduces the peak combustion temperature and therefore heat losses with particular benefits at part load conditions. However, one of the problems associated with the SI engines is the poor ignitability and low flame propagation rates that accompany lean mixtures. Out of the several methods that have been tried, pre-chamber ignition unit have been shown to improve lean combustion significantly. Though beneficial in extending the lean operation, the application of torch chambers in small engines is very scarce due to the challenges like the need to use tiny pre-chamber volumes and constraints in mounting and orientation of the pre-chamber on the compact engine cylinder head and also locating the sparkplug and the injector on the small prechamber. As used herein and after, the term small bore spark -ignition engines (SI engines) and Internal Combustion (IC) engine are interchangeable used.

Design of a small volume (such as lee) pre-chamber ignition unit having a combination of radially inclined and axial orifices. The configuration is configured to enhance the ignition and combustion in small automotive IC engines. The pre-chamber ignition unit can be mounted on either on the side of Single overhead cam or overhead cam engines (SOHC engines) or the center of the cylinder head of Double overhead camshaft engines (DOHC engines).

A housing of the pre-chamber ignition unit can be easily fixed or removed from the housing of the IC engines with the help of first threads, and it offers flexibility to rotate the injector and fix it in a certain position.

The pre-chamber ignition unit incorporates a spray plume passage that facilitates the passage of fuel into the pre-chamber cavity without interacting with the spray plume. This passage is configured to help to reduce the volume of pre-chamber to volumes suitable for a small automotive Internal Combustion (IC) engines when multi -hole direct injectors are used for pre- chamber fuelling. In conventional pre-chambers ignition unit, the injector tip is directly introduced inside the pre-chamber cavity, and this is feasible as conventional pre-chambers have higher volumes and more space to mount the injector on the pre-chamber cavity.

The following description relates to systems and methods for a pre-chamber ignition unit for an internal combustion engine of an automobile vehicle. An Internal Combustion (IC) engine includes an internal combustion engine configured to combust an air-fuel mixture. The IC engine includes at least one ignition chamber formed by an engine cylinder, a piston, and capped by a cylinder head. The at least one ignition chamber of the IC engine includes a at least one corresponding pre-chamber ignition unit, such as shown by FIGS. 4A-4B. The at least one pre-chamber ignition unit includes a pre-chamber cavity formed between the ends of pre chamber top and pre chamber bottom, as shown in Figure 1. Further, at least one corresponding fuel injector unit is disposed over the head of the at least one corresponding pre-chamber ignition unit and disposed within the pre-chamber cavity. The air-fuel mixture may combust within the pre-chamber cavity, and the combusted mixture may be driven through at least one corresponding orifice positioned at a bottom portion of the pre chamber bottom. In one of the embodiments, the at least one pre-chamber ignition unit is positioned on one side of a cylinder head of the IC engine. In one of the embodiments, the pre-chamber ignition unit is positioned is disposed on the center of the cylinder head of the IC engine.

Referring to Figure 1, in which a pre-chamber ignition unit (104) is configured to be mounted on an internal combustion engine (102) of a vehicle (100) (not shown in the figures). The prechamber ignition unit (104) comprises at least one fuel injector (106) which is mounted on the pre-chamber ignition unit (104) such that the same allows for easy insertion, re-orienting, removal and fixing of the injector at a particular position on the pre-chamber ignition unit (104). In the conventional pre-chamber, the direct injector is press fitted with pre-chamber housing. In such a system, aligning the injector and its removal is difficult. To avoid that issue the aforesaid pre-chamber ignition unit was designed. The housing of the pre-chamber ignition unit (104) can be easily fixed or removed from the housing of the internal combustion engine (102) with the help of threads and sealed with a washer. Accordingly, the same offers flexibility to rotate the pre-chamber ignition unit (104) and fix it in a certain position. The pre-chamber ignition unit (104) can also be mounted at different angular positions by the use of shims.

In the pre-chamber ignition unit ( 104), a pre-chamber cavity ( 114) is formed where combustion of air-fuel mixture configured to take place. The pre-chamber cavity (114) being formed between ends of a pre chamber top (108) and a pre chamber bottom (110). At least one corresponding spark plug (112) is connected at the pre chamber top (108) to ignite the air-fuel mixture present in the pre-chamber cavity (114) of the at least one corresponding pre-chamber ignition unit (104). Further, the at least one pre-chamber ignition unit (104) comprising a prechamber axis passes through a centre of the pre chamber top (108) and the pre chamber bottom (110). Furthermore, at least one corresponding orifice (116, 116’), are disposed at a bottom portion (118) of the pre chamber bottom (110). Some orifices out of the one or more orifice (116, 116’) are inclined radially (116) and some are inclined axially (116’) on the bottom portion (118) of the pre chamber bottom (110).

In one of the embodiments, the pre chamber bottom (110) of the pre-chamber ignition unit (104) comprises an outer portion, such that the outer portion being detachably attached to the internal combustion engine (102). Further, at least a portion of the pre chamber bottom (110) comprising at least one orifice (116, 116’) being disposed within the internal combustion engine (102). In one of the embodiments, the outer portion of the pre chamber bottom (110) of the prechamber ignition unit (104) comprises a plurality of first threads, and wherein the pre chamber bottom (110) being detachably attached to the internal combustion engine (102) using the plurality of first threads.

Referring to figure 2 A which is a side view of the pre-chamber ignition unit (104) and figure 2B which is a bottom view of pre-chamber ignition unit (104), the pre-chamber ignition unit (104) has a unique combination of radially inclined (116) and axially inclined (116’) orifices configuration. In one of the embodiments, the pre-chamber ignition unit (104) comprising ‘n’ radially inclined the at least one orifice (116, 116’) making pre-defined degrees with respect to the pre-chamber axis and 360/(n-l) degrees apart from each other.

In one of the embodiments, the pre-chamber ignition unit (104) has 5 radially inclined orifices (116) making 55 degrees from a pre-chamber axis and 72 degrees apart from each other like a regular pentagon and one orifice in axially inclined (116’). The pre chamber axis is the imaginary vertical axis passing through the center of the bottom portion (118) of the pre chamber bottom (110). This arrangement improves a turbulence inside the pre-chamber cavity (114) and also improves the ignition quality and reduces the flame quenching at the walls in small IC engines, such as the internal combustion engine (102) of the IC vehicle (100).

In one of the embodiments, at least one orifice (116, 116’) being radially disposed on the bottom portion (118) of the pre chamber bottom (110) of the pre-chamber ignition unit (104). In one of the embodiments, at least one orifice (116, 116’) being inclined towards the prechamber axis. Further, remaining at least one orifice (116’) being disposed downwards along the pre-chamber axis.

In one of the embodiments, at least one orifice (116, 116’) being inclined away from the prechamber axis.

In one of the embodiments, at least one orifice (116, 116’) extending parallelly to the prechamber axis.

Referring to figure 3, the same reflect uses of a spray plume passage (310) in order to have volume of the pre-chamber ignition unit (104) as minimum such as lee. The spray plume passage (310) as shown is one way to achieve small volumes in the pre-chamber ignition unit (104). Without spray plume passage (310), a tip (not shown in the figures) of the fuel injector ( 106) had to be brought to the pre-chamber cavity (114) and in order to do this, the pre chamber top (108) ofthe pre-chamber ignition unit (104) has to be enlarged and this leads to an increase in pre-chamber volume which is undesirable. Further, the spray plume passage (310) configured to offset the location of the tip of the injector tip (106) while still allowing fuel spray to go inside the pre-chamber cavity (114) and hence the pre chamber top (108) of the pre-chamber ignition unit (104) can be made smaller and the volume of the pre-chamber ignition unit (104) can be reduced.

Referring to figures 4A and 4B which illustrates model sectional view of the pre-chamber ignition unit (104) connected with the IC engine (102) of the vehicle (100), the pre-chamber ignition unit (104) can be seen how the same is connected with the IC engine (102). More specifically, it is shown how the bottom portion ( 118) of the pre chamber bottom (110) having the at least orifice (116, 116’) become part of an ignition chamber (402) formed by a cylinder head (602) of the internal combustion engine (102). Further, an inlet port (404) which is used for inputting air fuel mixture in the ignition chamber (402) and an exhaust port (406) for exhaust of gasses from the ignition chamber (402) is also shown in figure 4A. In the present embodiment only one inlet port (404) and one exhaust port (406) has been shown, however there may be one or more inlet port (404) and one or more exhaust port (406) may be there in the internal combustion engine (102) of the vehicle (100). Furthermore, on dissecting the figure 4A along an imaginary axis BB we will be having figure 4B.

In figure 4B, we can see how the pre-chamber ignition unit (104) is assembled over the ignition chamber (402) of the internal combustion engine (102) of the vehicle (100). In the current embodiment, the at least one pre-chamber ignition unit (104), is disposed on one side of the cylinder head (602) of the internal combustion engine (102), however, the at least one prechamber ignition unit (104) can be disposed on the center of the internal combustion engine (102) depending upon the type of engine, volume of the cylinder, surface area of the cylinder head, volume of the pre-chamber ignition unit (104), or the like. In the current embodiment, the at least one pre-chamber ignition unit (104) is disposed at an angle 0 (not shown in figure) with respect to an imaginary axis passing through center of the cylinder head (602). The prechamber ignition unit (104) is disposed in such a way that the bottom portion (118) of the pre chamber bottom ( 110) is become part of the ignition chamber (402) and the one or more orifices (116, 116’) are disposed closer to the cylinder head (602).

In one of the embodiments of the present invention, the at least one pre-chamber ignition unit

(104) of the internal combustion engine (102) of the vehicle (100) comprises the at least one corresponding fuel injector (106), the at least one corresponding injector holder (107) which is connected to the at least one corresponding fuel injector (106) and the at least one corresponding spark plug (112) which is connected at the pre chamber top (108). The at least one corresponding pre-chamber cavity (114) is formed between ends of the pre chamber top (108) and the pre chamber bottom (110). Further, at least one corresponding orifice (116, 116’) being disposed on the bottom portion (118) of the pre chamber bottom (110). The air-fuel mixture being compressed and injected into the pre-chamber cavity (114) using the at least one corresponding fuel injector (106) of the at least one corresponding pre-chamber ignition unit (104). The at least one corresponding spark plug (112) of the at least one corresponding prechamber ignition unit (104) configured to produce a spark within the pre-chamber cavity (114) so as to ignite the compressed air-fuel mixture such that the ignited air-fuel mixture passes to the ignition chamber (402) of the internal combustion engine (102) via the at least one corresponding orifices (116, 116’) disposed at the bottom portion (118) of the pre chamber bottom (110) to provide stable lean mixture combustion.

In one of the embodiments of the present invention, the at least one fuel injector (106) is mounted using plurality of the injector mounting plates (120, 122). The plurality of the mounting plates ( 120, 122) is parallel to each other and connected to each other using fastening means (124). Further, fastening means (124) can be studs, bolts, screws, or the like, are used to support the fuel injector (106) and hold it in its place. Accordingly, the entire assembly can be easily removed and put back without disturbing the at least one corresponding fuel injector (106).

In one of the embodiments of the present invention, volume of the pre-chamber ignition unit (104) is between 0.2% to 1 % of volume of the internal combustion engine (102) of the vehicle (100). Further, the reduced volume of the pre-chamber ignition unit (104) adopted in the internal combustion engine (102) of the vehicle (100) according to the present invention allows minimization of the thermal losses due to the increase of the heat transfer surface.

In one of the embodiments of the present invention, the pre-chamber ignition unit (104) is connected with an Engine Control Unit (ECU) of the vehicle (100). The ECU receives input signals from various sensors that represent various engine operating conditions. The ECU may be configured to control the fuel intake of the pre-chamber ignition unit (104) as well as the timing of the pre-chamber ignition unit (104). Further, in one of the embodiments, ECU can be able to control the amount of fuel going through the pre-chamber ignition unit (104) as well as the ignition chamber (402) of the internal combustion engine (102). Based on the requirement, the ECU may only send the fuel to the pre-chamber ignition unit (104) or to the ignition chamber (402) or to both the pre-chamber ignition unit (104) and the ignition chamber (402). Accordingly, based on the requirement of the vehicle (100) the combustion rate of the fuel in the internal combustion engine (102) of the vehicle (100) can be varied using ECU.

In one of the embodiments of the present invention, the at least one pre-chamber ignition unit (104) is connected with a Port Fuel Injector (PFI) unit of the vehicle (100). In PFI, the fuel is delivered to the internal combustion engine (102) directly into the cylinder head (602). The fuel is sprayed on the valve, which then uses the heat from the valve to further atomize the fuel. Further, PFI uses a port outside the cylinder head (602) to deliver the fuel. In one of the embodiments of the present invention, the pre-chamber ignition unit (104) configured to work in conjunction with the PFI to provide stable lean mixture combustion. In one of the embodiments of the present invention, the internal combustion engine (102) comprising one or more cylinders and one or more pistons.

In one of the embodiments of the present invention, the pre-chamber ignition unit (104) is comprising one or more the spark plugs (112).

In one of the embodiments of the present invention, the spark plug (112) is surrounded by a jacket with thermal-conductive substance for reducing the operating temperature of the spark plug (112) by conducting heat away from the spark plug (112).

In one of the embodiments of the present invention, the internal combustion engine (102) comprises: at least one cylinder head (602) being disposed above a cylinder block and the cylinder block being disposed above a crankcase of the internal combustion engine (102). Further, the ignition chamber (402) formed by the cylinder head (602) and the at least one prechamber ignition unit (104) disposed over one side of the at least one corresponding cylinder head (602). The internal combustion engine (102) also comprises at least one inlet port (404) for inputting air-fuel mixture in the ignition chamber (402) and at least one exhaust port (406) for exhaust of gasses from the ignition chamber (402). The at least one pre-chamber ignition unit (104) comprising: at least one fuel injector (106) connected to the at least one corresponding injector holder (107). The at least one corresponding fuel injector (106) and the at least one corresponding spark plug (112) of the at least one corresponding one pre-chamber ignition unit (104) are connected at the pre chamber top (108) of the at least one corresponding pre-chamber ignition unit (104). The pre-chamber cavity (114) is formed between ends of the pre chamber top (108) and the pre chamber bottom (110). Furthermore, at least one corresponding orifice (116, 116’), are disposed at a bottom portion (118) of the pre chamber botom (110). The pre chamber botom (110) comprises an outer portion, such that the outer portion being detachably atached to the internal combustion engine (102). Moreover, at least a portion of the pre chamber botom (110) comprising the at least one corresponding orifice (116, 116’) being disposed within the internal combustion engine (102).

The spark plug (112) will produce a spark within the pre-chamber cavity (114) so as to ignite the compressed air fuel mixture such that the ignited air fuel mixture passes to the ignition chamber (402) of the internal combustion engine (102) via the one or more orifices (116, 116’) disposed at the botom portion (118) of the pre chamber botom (110) to provide stable lean mixture combustion.

In one of the embodiments of the present invention, at least one of the one or more orifices (116, 116’) being radially (116) disposed on the botom portion (118) of the pre chamber botom (110), wherein the at least one of the one or more orifices (116, 116’) being inclined towards the pre-chamber axis center of the botom portion (118) and remaining being inclined axially (116’) on the botom portion (118) of the pre chamber botom (110).

In one of the embodiments of the present invention, at least one of the one or more orifices (116, 116’) being radially (116) disposed on the botom portion (118) of the pre chamber botom (110), wherein the at least one of the one or more orifices (116, 116’) being inclined away from the pre-chamber axis center of the botom portion (118) and remaining being inclined axially (116’) on the botom portion (118) of the pre chamber botom (110).

In one of the embodiments of the present invention, at least one of the one or more orifices (116, 116’) being radially (116) disposed on the botom portion (118) of the pre chamber bottom (110), wherein the at least one of the one or more orifices (116, 116’) extending parallelly to the pre-chamber axis center of the bottom portion (118) and remaining being inclined axially (116’) on the bottom portion (118) of the pre chamber bottom (110).

In one of the embodiments of the present invention, 5 out of the one or more orifices (116, 116’) being radially (116) disposed and 1 being disposed axially.

In one of the embodiments of the present invention, the internal combustion engine (102) comprises one or more pre-chamber ignition unit ( 104) disposed over the one or more cylinder heads (602).

In one of the embodiments of the present invention, the internal combustion engine (102) is configured to connect with an Engine Control Unit (ECU) and a Port Fuel Injector (PFI) unit of the vehicle (100).

In one of the embodiments of the present invention, the internal combustion engine (102) comprising one or more the spark plugs (200) (not shown in the figures).

In one of the embodiments of the present invention, the one or more spark plugs (200) of the internal combustion engine (102) is surrounded by a jacket with thermal-conductive substance for reducing the operating temperature of the one or more spark plugs (200) by conducting heat away from the one or more spark plugs (200).

In one of the embodiments of the present invention, at least one of the one or more cylinder head (602) of the internal combustion engine (102) comprises an opening, such that the opening has a plurality of second threads. Further, at least one of the one or more pre-chamber ignition unit (104) being detachably attached to the at least one of the one or more cylinder head (602) via the opening using the plurality of second threads.

In one of the embodiments of the present invention, to make the connection between at least one of the one or more pre-chamber ignition unit (104) and the at least one of the one or more cylinder head (602) of the internal combustion engine (102), leak proof gasket or o-shaped rings, washer or the like are used.

In one of the embodiments of the present invention, the volume of said internal combustion engine (102) being between lOOcc to 300cc.

In one of the embodiments of the present invention, discloses a method of operating the internal combustion engine (102) with the pre-chamber ignition unit (104). The method comprising: injecting and compressing the air fuel mixture into the pre-chamber cavity (114) of the prechamber ignition unit ( 104), using the fuel inj ector ( 106) of the pre-chamber ignition unit ( 104) . Further, igniting the injected and compressed air-fuel mixture using the spark plug (112) which is connected to the pre-chamber cavity (114) of the pre-chamber ignition unit (104). Furthermore, transferring, the ignited air-fuel mixture, from the pre-chamber cavity (114) of the pre-chamber ignition unit (104) to the ignition chamber (402) of the internal combustion engine (102) via the at least one of one or more orifices (116, 116’) disposed at the bottom portion ( 118) of the pre chamber bottom ( 110) of the pre-chamber ignition unit ( 104) to provide stable lean mixture combustion. According to the present invention, the pre-chamber ignition unit (104) is used in the small volume internal combustion engines (102) of the vehicle (100) which is configured to provide stable lean mixture of combustion which results in enhance efficiency and reduce engine-out NOx, HC and CO emissions. Further, the pre-chamber ignition unit (104) having a combination of the radially inclined and axial orifices that will enhance the ignition and combustion in small volume internal combustion engines (102) of the vehicle (100). The pre-chamber ignition unit (104) can be mounted either on the side (for Single overhead cam or overhead cam engines (SOHC engines)) or the center (for Double overhead camshaft engines (DOHC engines)) of the cylinder head. Furthermore, the pre-chamber ignition unit (104) can be easily fixed or removed from the housing of the internal combustion engine (102) with the help of threads and sealed with a washer.

In one of the embodiments of the present invention, during the high load conditions the air-fuel mixture will be supplied only by the PFI and the quantity of injection is adjusted to get stoichiometric air-fuel ratio. As stoichiometric mixture has very good ignitability, there is no need for direct injection of air-fuel mixture inside the pre-chamber ignition unit (104) and hence direct air-fuel mixture injection is not used or will be restricted to once after few cycles. Whereas, in the lean and ultra-lean modes where the mixture entering the ignition chamber (402) from the pre-chamber ignition unit (104) during compression is lean, the port fuel injector will be used to bring the fuel mixture in the pre-chamber ignition unit (104) to slightly rich fuel-air ratio for better ignition and combustion inside the ignition chamber (402) of the internal combustion engine (102).

The pre-chamber ignition unit (104) significantly enhanced the combustion rates and resulted in much stronger ignition compared to conventional ignition. This was due to distributed ignition by flame jets which resulted in higher ignition energy and more turbulence in the ignition chamber (402) of the internal combustion engine (102) due to high velocity of the flame jets. The pre-chamber ignition unit (104) supported ultra-lean combustion in the ignition chamber (402) of the internal combustion engine (102) of the vehicle (100) at air-fuel ratio of 30 with more than 90% combustion efficiency. This kind of ultra-lean combustion is not possible with conventional spark ignition. The ultra-lean combustion was sustained even at airfuel ratio of 34. Whereas in a conventional engine the lean limits will be air-fuel ratio 20 for stable combustion. The pre-chamber ignition unit (104) improved the heat release rates and cumulative heat release and resulted in higher indicated thermal efficiency. The pre-chamber ignition unit (104) also gave benefits in the form of reduced HC and CO at full loads and part loads. Further, NOx was reduced in part loads during lean and ultra-lean modes of operations.

In one of the embodiments of the present application, as shown in figure 5, the pre-chamber ignition unit (104) can also be mounted at center of the cylinder head (602) disposed above a cylinder block and the cylinder block being disposed above a crankcase. When the pre-chamber ignition unit ( 104) is mounted on the center, the distance each flame j et has to travel to consume the entire charge reduces. And therefore, the time taken for total charge consumption reduces and spark can be retarded for same Indicated Mean Effective Pressures (IMEP) when compared with side spark case. This reduces pumping losses and gives higher work per cycle.

Figures 6 to 14 represent working conditions comparison of the pre chamber ignition unit of the small volumed automobile IC engine with respect to the conventional small volumed automobile IC engine in accordance with one or more embodiments of the present disclosure. Further, for the comparison, at full load condition both the modes were operated with wide open throttle (WOT) but the excess air ratio for the pre-chamber mode was chosen to be 1.4 to match the conventional mode which operates at X=l.

Referring to figure 6, the same shows graph 600, representing the conditions chosen for comparison between conventional mode and pre-chamber ignition unit (104) mode. Comparisons were done at same Indicated Mean Effective Pressures (IMEP). At full load condition both the modes were operated with wide open throttle (W OT) but the excess air ratio X for the pre-chamber mode was chosen to be 1.4 to match the IMEP of conventional mode which operates at X=l. The same clearly reflects that the IMEP will remain almost same using the conventional mode and pre-chamber ignition unit (104) mode.

Referring to figure 7, the same shows graph 700, the same compares the indicated thermal efficiencies at full load and part load conditions. The indicated efficiency increased by 10% in both full load and part load conditions with the use of pre-chamber.

Referring to figure 8, the same shows graph 800, the same compares the Indicated Specific Fuel Consumption (ISFC) at full load and part load conditions. The ISFC reduced by 21% at full load and 25% at part load condition.

Referring to figure 9, the same shows graph 900, the same compares the combustion efficiencies at full load and part load conditions. The combustion efficiencies are almost same with both modes. This shows the ability of pre-chamber ignition unit (104) to enhance the ignitability of the lean mixtures. Referring to figure 10, the same shows graph 1000, the same compares the peak pressure during combustion at part load and full load conditions. The peak pressure with the pre-chamber mode increases by 12% at full load condition and 21% at part load conditions.

Referring to figure 11, the same shows graph 1100, the same compares the maximum rate of pressure rise during combustion at full load and part load conditions. The rate of pressure rise is higher by 10% with the pre-chamber combustion unit (104) at both load conditions but the rates are lesser compared to the knock limits and hence the combustion would be smooth with no knocks and less noise vibration and harshness.

Referring to figure 12, the same shows graph 1200, the same compares the Nitrogen Oxide (NOx) emissions at full load and part load conditions. The NOx reduced significantly by 88.5% at full load and 91.6% at part load condition. Due to significant reduction in NOx the after- treatment system can have only an oxidation catalyst for oxidizing Hydrocarbon (HC) and Carbon monoxide (CO).

Referring to figure 13, the same shows graph 1300, the same compares the HC emissions at full load and part load conditions. The HC emissions are lower in part load conditions with a pre-chamber and higher at full load condition.

Referring to figure 14, the same shows graph 1400, the same compares the CO emissions at full load and part load conditions. The CO emissions reduce significantly with the use of prechamber. The CO reduces by 95.6% at full load and by 82.63% at part loads. The pre-chamber ignition unit (104) developed can also be used for hybrid engines in lean bum modes as the pre-chamber ignition unit (104) provides a sustainable strong ignition with lean mixtures which result in higher efficiencies and lesser emissions compared to conventional modes without much change to engine geometry.

The pre-chamber ignition unit (104) as disclosed in the present application is able to improve lean combustion significantly. Further, the pre-chamber ignition unit (104) also significantly improves the combustion rates inside the ignition chamber (402) of the internal combustion engine (102) of the vehicle (100). This arrangement of the pre-chamber ignition unit (104) improves the turbulence inside the pre-chamber cavity (114) and improves the ignition quality and reduces the flame quenching at the walls of the internal combustion engine (102) of the vehicle (100). The pre-chamber ignition unit (104) also improved the heat release rates and cumulative heat release and resulted in higher indicated thermal efficiency. The pre-chamber ignition unit (104) also gave benefits in the form of reduced HC and CO at full loads and part loads. Further, NOx was reduced in part loads during lean and ultra-lean modes of operations.

Accordingly, using the configuration of the pre-chamber ignition unit (104) as disclosed in the present application, the small volume pre-chamber ignition unit (104) can be easily placed over the cylinder head (602) of the internal combustion engine (102) of the vehicle (100). Further, the present application also allows for easy mounting, adjusting and removal of the prechamber ignition unit (104) when compared with the conventional pre-chambers that use interference fit between the cylinder head and the pre-chamber body. Furthermore, the prechamber ignition unit (104) can be easily fixed or removed from the cylinder head (602) of the internal combustion engine (102) with the help of threads and it offers flexibility to rotate the injector and fix it in a certain position. The entire pre-chamber ignition unit (104) can be easily removed and put back without disturbing the fuel injector (106).

In view of the above, the claimed steps as discussed above are not routine, conventional, or well understood in the art, as the claimed steps enable the following solutions to the existing problems in conventional technologies.

The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. It will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.

Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. It should be appreciated that the following figures may not be drawn to scale.

Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as a discussion of other potential embodiments or implementations of the inventive concepts presented herein. An overview of embodiments of the invention is provided below, followed by a more detailed description with reference to the drawings. The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.

In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of’, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

Claims

29

Claims:

1. A pre-chamber ignition unit (104), said pre-chamber ignition unit (104) comprises: at least one fuel injector (106); at least one injector holder (107), said at least one injector holder (107) being connected to said at least one fuel injector (106); a pre chamber top (108) and a pre chamber bottom (110); at least one spark plug (112), said at least one spark plug (112) being connected to said pre chamber top (108); a pre-chamber cavity (114), said pre-chamber cavity (114) being formed between ends of said pre chamber top (108) and said pre chamber bottom (110); and at least one orifice (116, 116’), said at least one orifice (116, 116’) being disposed at a bottom portion (118) of said pre chamber bottom (110); wherein said pre chamber bottom (110) comprises an outer portion, wherein said outer portion being detachably attached to an internal combustion engine (102), and wherein at least a portion of said pre chamber bottom (110) comprising said at least one orifice (116, 116’) being disposed within said internal combustion engine (102).

2. The pre-chamber ignition unit (104) as claimed in claim 1, wherein said at least one fuel injector (106) being configured to compress said air-fuel mixture, wherein said compressed air-fuel mixture being injected into said pre-chamber cavity (114).

3. The pre-chamber ignition unit (104) as claimed in claim 2, wherein said at least one spark plug (112) being configured to produce a spark within said pre-chamber cavity (114), wherein said spark being configured to ignite said compressed air-fuel mixture. 30

4. The pre-chamber ignition unit (104) as claimed in claim 3, wherein said ignited air-fuel mixture passes to an ignition chamber (402) of said internal combustion engine (102) of a vehicle (100) via said at least one orifice (116, 116’).

5. The pre-chamber ignition unit (104) as claimed in claim 1, comprising a pre-chamber axis passes through a centre of said pre chamber top (108) and said pre chamber bottom (HO).

6. The pre-chamber ignition unit (104) as claimed in claim 1, wherein said at least one orifice (116, 116’) being radially disposed on said bottom portion (118) of said pre chamber bottom (110).

7. The pre-chamber ignition unit (104) as claimed in claim 5, wherein said at least one orifice (116, 116’) being inclined towards said pre-chamber axis, and wherein remaining said at least one orifice (116’) being disposed downwards along said prechamber axis.

8. The pre-chamber ignition unit (104) as claimed in claim 5, wherein said at least one orifice (116, 116’) being inclined away from said pre-chamber axis.

9. The pre-chamber ignition unit (104) as claimed in claim 5, wherein said at least one orifice (116, 116’) extending parallelly to said pre-chamber axis.

10. The pre-chamber ignition unit (104) as claimed in claim 5, wherein said pre-chamber ignition unit (104) comprising ‘n’ radially inclined said at least one orifice (116, 116’) making pre-defined degrees with respect to said pre-chamber axis and 360/(n-l) degrees apart from each other. The pre-chamber ignition unit (104) as claimed in claim 1, comprising a spray plume passage (310) to connect said at least one fuel inj ector ( 106) to said pre-chamber cavity (114). The pre-chamber ignition unit (104) as claimed in claim 1, wherein at least one fuel injector (106) being mounted on a plurality of injector mounting plates (120, 122), said plurality of mounting plates (120, 122) being parallel to each other and connected to each other using a fastening means (124). The pre-chamber ignition unit (104) as claimed in claim 4, wherein volume of said prechamber ignition unit (104) being between 0.2% to 1 % of volume of said internal combustion engine (102) of said vehicle (100). The pre-chamber ignition unit (104) as claimed in claim 1, wherein said pre-chamber ignition unit (104) being connected with at least one of an Engine Control Unit (ECU) and a Port Fuel Injector (PFI) unit of said vehicle (100). The pre-chamber ignition unit (104) as claimed in claim 4, wherein said pre-chamber ignition unit (104) being disposed on one side of a cylinder head (602) of said internal combustion engine (102). The pre-chamber ignition unit (104) as claimed in claim 1, wherein said outer portion comprises a plurality of first threads, and wherein said pre chamber bottom (110) being detachably attached to said internal combustion engine (102) using said plurality of first threads. The pre-chamber ignition unit (104) as claimed in claim 1, wherein volume of said internal combustion engine (102) being between lOOcc to 300cc. An internal combustion engine (102) of a vehicle (100), said internal combustion engine (102) comprising: at least one cylinder head (602), said at least one cylinder head (602) being disposed above a cylinder block and said cylinder block being disposed above a crankcase; an ignition chamber (402), said ignition chamber (402) being formed by said at least one cylinder head (602); at least one inlet port (404) for inputting air-fuel mixture in said ignition chamber (402); at least one exhaust port (406) for exhaust of gasses from said ignition chamber (402); and at least one pre-chamber ignition unit (104) disposed over one side of said at least one cylinder head (602), wherein said at least one pre-chamber ignition unit (104) comprising: at least one fuel injector (106); at least one injector holder (107), said at least one injector holder (107) being connected to said at least one fuel injector (106); 33 a pre chamber top (108) and a pre chamber bottom (110); at least one spark plug (112), said at least one spark plug (112) being connected to said pre chamber top (108); a pre-chamber cavity (114), said pre-chamber cavity (114) being formed between ends of said pre chambertop (108) and said pre chamber bottom (110); and at least one orifice (116, 116’), said at least one orifice (116, 116’) being disposed at a bottom portion (118) of said pre chamber bottom (110); wherein said pre chamber bottom (110) comprises an outer portion, wherein said outer portion being detachably attached to an internal combustion engine (102), and wherein at least a portion of said pre chamber bottom (110) comprising said at least one orifice (116, 116’) being disposed within said internal combustion engine (102).

19. The internal combustion engine (102) of said vehicle (100), as claimed in claim 18, wherein volume of said at least one pre-chamber ignition unit (104) being between 0.2% to 1 % of volume of said internal combustion engine (102) of said vehicle (100).

20. The internal combustion engine (102) of said vehicle (100), as claimed in claim 18, wherein said at least one pre-chamber ignition unit (104) being connected with at least one of an Engine Control Unit (ECU) and a Port Fuel Injector (PFI) unit of said vehicle (100).

21. The internal combustion engine (102) of said vehicle (100), as claimed in claims 18, wherein said at least one cylinder head (602) of said internal combustion engine (102) 34 comprises an opening, wherein said opening has a plurality of second threads, wherein said at least one pre-chamber ignition unit (104) being detachably attached to said at least one cylinder head (602) via said opening using said plurality of second threads.

22. The internal combustion engine (102) of said vehicle (100), as claimed in claims 18, wherein volume of said internal combustion engine (102) being between lOOcc to 300cc.

23. A method of operating an internal combustion engine (102) with at least one prechamber ignition unit (104), said method comprising step of: injecting, by at least one fuel injector (106), a compressed air-fuel mixture into a pre-chamber cavity (114) of said at least one pre-chamber ignition unit (104); igniting, by at least one spark plug (112), said injected and said compressed airfuel mixture; transferring, said ignited air-fuel mixture from a pre-chamber cavity (114) of said at least one pre-chamber ignition unit (104) to an ignition chamber (402) of said internal combustion engine (102) via at least one orifice (116, 116’).

24. The method of operating said internal combustion engine (102) with said at least one pre-chamber ignition unit (104) as claimed in claim 23, comprising combusting said air-fuel mixture in said ignition chamber (402) of said internal combustion engine (102) via said ignited air-fuel mixture received from said pre-chamber cavity (114) of said at least one pre-chamber ignition unit (104). 35 The method of operating said internal combustion engine (102) with said at least one pre-chamber ignition unit (104) as claimed in claim 23, wherein injecting said air-fuel mixture to said ignition chamber (402) of said internal combustion engine (102) using at least one inlet port of said internal combustion engine (102). The method of operating said internal combustion engine (102) with said at least one pre-chamber ignition unit (104) as claimed in claim 23, wherein exhaust gases being released from said internal combustion engine (102) via at least one exhaust port.