DESC:DISCLAIMER
[0001] Portions of this patent document may contain material that may be subject to Copyright or Trademark protection. The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office file or records, but otherwise reserves all copyright rights and trademarks whatsoever. All copyrights and trademarks are owned by Indian Institute of Science, Bangalore.

TECHNICAL FIELD
[0002] The present disclosure relates in general to two-stroke internal combustion (IC) engines. More particularly, the present disclosure relates to a two-stroke internal combustion engine with opposed pistons operable on gaseous fuels.

BACKGROUND
[0001] The information in this section merely provides background information related to the present disclosure and may not constitute prior art(s) for the present disclosure.
[0002] Conventional internal combustion engines emit high levels of greenhouse gases and other carbon emissions, primarily due to utilization of fossil fuels. These fossil fuels, when burned, release untreated emissions into a surrounding environment. Fuel efficiency of conventional internal combustion engines is often compromised, leading to higher fuel consumption. This inefficiency has prompted the automotive industry's transition from two-stroke engines to four-stroke engines. Further advancements in the efficiency of the two-stroke internal combustion engines render them competitive and versatile compared to their four-stroke counterparts. Compressed Natural Gas (CNG) gas had been used for cutting down the emissions, said CNG gas being a fossil fuel and further use of other gases as fuels is still under consideration. However, some attempts were made to use hydrogen as an alternative fuel besides other available renewable energy sources such as solar and wind power. Utilization of hydrogen as fuel in engines for power generation and transportation can significantly mitigate greenhouse gas emissions from internal combustion engines.
[0003] In addition, the conventional four-stroke engines use a valve train and associated high-precision parts such as cams, valves, valve-seats, rocket arms, etc., resulting in more additional moving components, increasing an overall weight of the engine and thereby reducing the efficiency of the engine.
[0004] Efforts to address the above constraints have been explored in prior art. For instance, a Patent Application No. 201621020854 relates to an opposed piston opposed cylinder engine describing an IC engine featuring opposing cylinders and pistons arranged such that one cylinder is disposed coaxially opposite to the other. However, as a mechanism of an opposed-piston engine with a four-stroke configuration utilizes two cylinders and four pistons, said mechanism is less fuel-efficient when compared to the two-stroke engines. Additionally, the above opposed piston uses standard fossil fuels like blends of hydrogen, CNG, ammonia, and biogas without any combination or blending of two or more fossil fuels.
[0005] Another Patent Application No. 201717032998 relates to an asymmetrically shaped combustion chamber designed for opposed piston engine describing a combustion chamber elongated asymmetrical shape in a longitudinal section, aligned along a chamber centre line, between diametrically opposed openings through which fuel is injected. However, as combustion chamber’s shape is developed for a diesel-fuelled engine operating on the compression ignition concept, usage of diesel fuel does not address the issue of carbon emissions.
[0006] Another Patent No. US20230025982A1 describes a hydrogen-powered opposed-piston engine where a two-stroke cycle uniflow-scavenged opposed-piston engine using hydrogen as a fuel is described. However, as the fuel is restricted to hydrogen, reliance on injection pressures between 50 to 150 bar, and absence of high-performing spark plugs for hydrogen ignition does not address the current challenge.
[0007] Another Patent No. US 20230265786A1 discloses a hydrogen-fuelled opposed-piston engine comprising at least one cylinder and a pair of pistons moving in opposite directions within the cylinder bore where the engine's operational method involves alternating between two ignition modes, a first mode and a second mode. The first mode utilizes an externally generated ignition impulse to ignite the hydrogen fuel and charge air mixture, and a second mode relying on compression to ignite the mixture. However, as the efficiency of the hydrogen-fuelled opposed-piston engine when operating in said modes necessitates a higher fuel volume, indicating reduced fuel efficiency.
[0008] There is, therefore, a requirement in the art to overcome the above-mentioned problem of enhancing the fuel efficiency of the two-stroke engine by providing a simple, compact, and efficient two-stroke internal combustion engine with opposed pistons operable on gaseous fuels.

OBJECTS OF THE PRESENT DISCLOSURE
[0009] A general object of the present disclosure is to overcome the problems associated with existing two-stroke internal combustion (IC) engines, by providing a simple, compact, and efficient gaseous-fuelled two-stroke internal combustion engine with opposed pistons operable using gaseous fuels.
[0010] Another object of the present disclosure is to provide a two-stroke IC engine with a stroke volume ranging from 20 cc to 500 cc.
[0011] Yet another object of the present disclosure is to provide a two-stroke IC engine with a maximum scavenging efficiency.
[0012] Yet another object of the present disclosure is to provide a two-stroke IC engine where fuel is injected at a low pressure.
[0013] Yet another object of the present disclosure is to provide a low-pressure port fuel injector at an intake port that may be oriented in a manner such that, upon uncovering of the intake port by a piston, the fuel is injected directly into a cylinder block.
[0014] Yet another object of the present disclosure is to provide a two-stroke IC engine that uses an ignited combustion mixture in combination with one or more electrical impulses to ignite a gaseous fuel in the cylinder block.
[0015] Yet another object of the present disclosure is to provide a two-stoke IC engine that uses a combination of any blends of hydrogen, compressed natural gas (CNG), ammonia, and biogas.
[0016] Yet another object of the present disclosure is to provide a two-stroke IC engine that uses one or more spark plugs and one or more fuel injectors actuated by an electronic control unit (ECU) to improve fuel efficiency of the two-stroke IC engine.

SUMMARY
[0017] Aspects of the present disclosure pertain to two-stroke internal combustion (IC) engines. More particularly, the present disclosure relates to a two-stroke internal combustion engine with opposed pistons operable on gaseous fuels.
[0018] According to an aspect, the disclosed two-stroke internal combustion (IC) engine operable on gaseous fuels includes a cylinder block. The cylindrical block includes opposed pistons. The opposed pistons include a first piston and a second piston slidably disposed within the cylinder block. The first piston head of the first piston slides towards and away from a second piston head of the second piston upon combustion of a mixture of air and one or more gaseous fuels within the cylindrical block. The air- gaseous fuel mixture includes air and one or more gaseous fuels. The one or more gaseous fuels correspond to any combination of blends of hydrogen, compressed natural gas (CNG), ammonia, and biogas.
[0019] The gaseous fuel is injected into the cylinder block through a first injector (port enabled direct injection (PEDI)) and a second fuel injector. The first injector is a low-pressure port fuel injector. The first injector is configured on one or more first ports of the cylinder block in an angular orientation. The first injector injects a specific quantity of gaseous fuel at low pressure into a combustion chamber of the cylinder block before the first piston head covers the one or more first ports upon sliding from a Bottom Dead Center (BDC) to a Top Dead Center (TDC).
[0020] The second injector is directly configured on the cylinder block and located adjacent to the first port. The second injector injects a remaining quantity of gaseous fuel into the cylinder block for combustion process as a sequel to first gas injector before the first piston head coves mouth of the second injector upon sliding from BDC to TDC. The deficiency of the gaseisud fuel dispensed from the first injector is compensated and a sufficiency of an air-gaseous fuel mixture is maintained within the combustion chamber during the combustion process. The air-gaseous fuel mixture formed within the cylindrical block gets ignited by plasma. The plasma is generated by one or more spark plug assemblies within the combustion chamber of the cylindrical block. The combustion of the air-gaseous fuel mixture within the combustion chamber results in sliding of the opposed pistons and enhances thermal efficiency of the two-stroke IC engine.
[0021] In an embodiment, the gaseous fuel injected into the cylinder block through the first injector and the second injector may be instantly ignited within the cylinder block. The instant ignition may be enabled through one or more electrical pulses generated by at least one spark plug assembly of the one or more spark plug assemblies to enable the first piston to slide between a medial portion of the cylinder block and the TDC, and the second piston to slide between the medial portion and the BDC for enhancing thermal efficiency of the two-stroke IC engine.
[0022] In an embodiment, the one or more spark plug assemblies may be directly configured on a cylindrical portion of the cylinder block. A nanosecond pulse discharged plasma, generated by one of the one or more spark plug assemblies in combination with the one or more electrical pulses generated by other spark plug assemblies into the cylindrical block may instantaneously ignite the air-gaseous fuel mixture within the cylinder block.
[0023] In an embodiment, the two-stroke IC engine may include an electronic control unit (ECU). The ECU may be in communication with the first injector, the second injector, and one or more spark plug assemblies. The ECU may be configured for injecting a required quantity of the gaseous fuel into the cylinder block by actuating the first injector and thereafter the second injector. In addition, the ECU may generate the required plasma and electric pulses for enabling combustion of the air-gaseous fuel mixture within the cylinder block using the one or more spark plug assemblies.
[0024] In an embodiment, at least one spark plug assembly of the one or more spark plug assemblies may include a pre-combustion chamber, a third injector, and a spark plug. The pre-combustion chamber may be adapted to receive a mixture of the air and the one or more gaseous fuels. The third injector may be in fluidic communication with the pre-combustion chamber. The third injector may be adapted to inject the gaseous fuel into the pre-combustion chamber upon receiving ambient air and the gaseous fuels from a fuel tank thereby forming a combustible fuel-air mixture in the pre-combustion chamber. The spark plug may be electrically coupled to the pre-combustion chamber. The spark plug may be adapted to ignite the air-gaseous fuel mixture in the pre-combustion chamber for creating hot burning gas enters the combustion chamber of the cylinder block and ignites the resulting air-gaseous fuel mixture in the combustion chamber.
[0025] In an embodiment, the ECU may be configured for injecting a required quantity of gaseous fuel into the pre-combustion chamber by using a third injector. Additionally, the ECU may be generating required sparks for igniting an air-gaseous fuel mixture in the pre-combustion chamber using the spark plug. The air-gaseous fuel mixture may be formed upon injected gaseous fuel being mixed with resulting air available within the pre-combustion chamber.
[0026] In an embodiment, the first port housing the first injector therewithin may be coupled to a supercharger of the two stroke IC engine. The first port may be adapted to receive air compressed by the supercharger along with the one or more gaseous fuels from the first injector. The first port facilitates the injection of gaseous fuel along air into the cylinder block.
[0027] In an embodiment, the cylinder block may include one or more second ports. The second ports may be configured for scavenging exhaust gases from the combustion chamber of the cylinder block.
[0028] In an embodiment, exhaust gases within the cylinder block may be scavenged out from the cylinder block through the one or more second ports when the gaseous fuel is sprayed into the cylinder block through the first port.
[0029] In an embodiment, the two-stroke IC engine may include a first crank shaft coupled to the first piston. The first crank shaft may be configured within the cylinder block. The first crank shaft may be adapted to convert a horizontal movement of the first piston into a rotational movement. Further, the two-stroke IC engine may include a second crank shaft. The second crank shaft may be coupled to the second piston. The second crank shaft may be configured within the cylinder block. The second crank shaft may be adapted to convert a horizontal movement of the second piston into a rotational movement.
[0030] In an embodiment, the first piston and the second piston may define a predefined stroke volume within the cylinder block. The predefined stroke volume may correspond to a range between 20 cc to 500 cc.
[0031] In an embodiment, the predefined pressure of the one or more gaseous fuels may correspond to a range between 3 bar to 10 bar.
[0032] In an embodiment, the two-stroke engine may include a second non-return valve. The second non-return valve may be configured between each of the third injector and the one or more spark plug assemblies. The second non-return valve may prevent back flow of the one or more gaseous fuels into the third injector.
[0033] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF FIGURES
[0034] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0035] FIGs. 1A and 1B illustrate schematic views of a gaseous-fuelled two-stroke internal combustion (IC) engine with opposed pistons, in accordance with an embodiment of the present disclosure.
[0036] FIG. 2 illustrates a schematic view of a spark plug assembly with a pre-chamber for ignition of an ultra-lean air-gaseous fuel mixture, in accordance with an embodiment of the present disclosure.
[0037] Skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of embodiments of the present disclosure.

DETAILED DESCRIPTION
[0038] Hereinafter, various exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings, where it should be understood that all these drawings and description are only presented as exemplary embodiments. It is to be noted that based on the subsequent description, several alternative embodiments may be conceived that may have a structure similar to that disclosed herein and/or formed by a method as disclosed herein, and all such alternative embodiments may be used without departing from the principle of the disclosure as claimed herein, and hence such alternative embodiments are construed to fall within the scope of the present disclosure.
[0039] All references in the specification made to “one embodiment,” “an embodiment,” “a preferred embodiment” etc., indicate that the embodiment described herein may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases may not be necessarily referring to the same embodiment. It should also be understood that various terminology used herein is for the purpose of describing a particular embodiment or specific embodiments only and the use of such terminology is not intended to be limiting the scope and spirit of the present disclosure. As used herein, the singular forms “a,” “an” and “the” may also include the plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “has” and “including” used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence of one or more other features, elements, components and/or a combination thereof. For example, the term “multiple” used here indicates “two or more;” the term “and/or” used here may comprise any or all combinations of one or more of the items listed in parallel. Definitions of other terms will be specifically provided in the following description. Furthermore, in the following description, some functions, or structures well-known to those skilled in the art will be omitted in order not to obscure embodiments of the disclosure in the unnecessary details.
[0040] It may be appreciated that these exemplary embodiments are provided only for enabling those skilled in the art to better understand and then further implement the present disclosure, not intended to limit the scope of the present disclosure in any manner. Besides, in the drawings, for a purpose of illustration, optional steps, modules, and units may be illustrated in dotted-line blocks.
[0041] Exemplary embodiments of the present disclosure relate a two-stroke internal combustion engine with opposed pistons operable on gaseous fuels.
[0042] According to an aspect, the proposed two-stroke internal combustion (IC) engine is designed to operate on one or more gaseous fuels. The two-stroke IC engine includes a cylinder block housing two opposed pistons namely a first piston and a second piston. These opposed pistons are arranged such that the first piston head of the first piston moves towards and away from the second piston head of the second piston during the combustion process.
[0043] The gaseous fuel which could be any one of fuels such as hydrogen, compressed natural gas (CNG), ammonia, and biogas individually or in blends is injected into the cylinder block through a first injector and a second injector where the first injector may be configured for port enabled direct injection (PEDI) injects a specific quantity of gaseous fuel at low pressure along with air through the first port into the combustion chamber before the first piston head covers the first port as it moves from Bottom Dead Center (BDC) to Top Dead Center (TDC).
[0044] The second injector, directly mounted on the cylinder block adjacent to the first port, injects the remaining required quantity of gaseous fuel which occurs as a sequel to the first injector before the first piston head covers the mouth of the second injector during its movement from BDC to TDC such that sequential injection ensures that any deficiency in the gaseous fuel from the air-gaseous fuel mixture is compensated, maintaining the sufficiency of the air- gaseous fuel mixture within the combustion chamber during the combustion process.
[0045] Further, the air-gaseous fuel mixture within the cylinder block gets ignited by plasma that is generated by at least one spark plug assembly of the one or more spark plug assemblies in combination with one or more electrical impulses generated from a conventional spark plug of the one or more spark plug assemblies within the combustion chamber where said ignition results in the sliding of the opposed pistons with improved thermal efficiency of the two-stroke IC engine and reduced emissions.
[0046] Various embodiments of the present disclosure will be explained in detail with reference to FIGs. 1A-2.
[0047] Referring to FIGs. 1A and 1B, a schematic view of a gaseous-fuelled two-stroke internal combustion (IC) engine (hereinafter referred to as “IC engine 100” or “engine 100”) with opposed pistons operable on one or more gaseous fuels is disclosed. In an embodiment, the two-stroke engine 100 may include a cylinder block 102 having a size ranging from 20 cc to 500 cc, and may include a plurality of ports. In an exemplary embodiment, the cylinder block 102 may be in multiple for higher power requirements. The plurality of ports may include one or more first ports 108-1A, 108-1B, and one or more second ports 108-2A, 108-2B. The first port 108-1A may be configured for receiving ambient air into the cylinder block 102, and the second port 108-2B may be configured for exiting the exhaust gases from the cylinder block 102 upon combustion of the air-gaseous fuel mixture.
[0048] Further, an outer surface of the cylinder block 102 may be water-cooled or air-cooled to reduce the high temperature of the cylinder block 102 due to combustion operation therewithin. Type of cooling system used for reducing the high temperature of the cylinder block 102 may be based on the size and power requirements of the two-stroke engine 100.
[0049] In an embodiment, the cylinder block 102 may have opposed pistons that includes a first piston 112 and a second piston 114 slidably disposed within the cylinder block 102 such that a first piston head 112-1 of the first piston 112 slides towards and away from a second piston head 114-1 of the second piston 114 upon combustion of a air-gaseous fuel mixture of air and one or more gaseous fuels that comprises any combination of blends of hydrogen, compressed natural gas (CNG), ammonia, and biogas within the cylinder block 102.
[0050] In an embodiment, the air-gaseous fuel mixture may be injected into the cylinder block 102 through a first injector (port enabled direct injection (PEDI)) 104-1 and a second fuel injector 106 such that the first injector 104-1 configured on the first port 108-1A of the one or more first ports 108-1A,108-1B of the cylinder block 102 in an angular orientation may inject a specific quantity of gaseous fuel at low-pressure into a combustion chamber 122 of the cylinder block 102 before the first piston head 112-1 covers the first port 108-1A upon sliding from a Bottom Dead Center (BDC) to a Top Dead Center (TDC) and At least one first port 108-1A,108-1B may simultaneously inject air that is compressed by a supercharger 132 into the combustion chamber 122.
[0051] In an embodiment, the second injector 104-2 directly configured on the cylinder block 102, located adjacent to the first port 108-1A may inject a remaining quantity of gaseous fuel that is required the cylinder block 102 for combustion process as a sequel to first gas injector 106 when the first piston head 112-1 uncovers mouth of the second injector 104-2 upon sliding from the Bottom Dead Center (BDC) to the Top Dead Center (TDC) such that the deficiency of gaseous fuel dispensed from the first injector 104-1 is compensated such that the sufficiency of the air-gaseous fuel mixture is maintained within the combustion chamber 122 during combustion process.
[0052] In an embodiment, the first piston 112 may be configured for sliding between a top dead center (TDC) and a first bottom dead center (BDC) within the cylinder block 102, such that the one or more first ports 108-1 may be positioned at the first piston 112’s first BDC position. The second piston 108-2 may be configured for sliding between the TDC and a second BDC within the cylinder block 102, such that the one or more second ports 108-2 may be positioned at the second piston 114’s second BDC position.
[0053] In an embodiment, the first piston 112 may include a first piston head 112-1, and the second piston 114 may include a second piston head 114-1. In an exemplary embodiment, the cylinder block 102 may include two opposed pistons such that, based on the size and power requirements, the cylinder blocks 102 may be increased. The basic function of the first piston 112 and the second piston 114 may be to transmit the force exerted on the first piston head 112-1 and the second piston head 114-1 upon combustion of the air-gaseous fuel mixture within the cylinder block 102 to rotate a first crankshaft 116 and a second crankshaft 118. Further, a synchronous motion of the first piston 112 and the second piston 114 may be achieved by coupling the first crankshaft 116 and the second crankshaft 118 through a gear train, where such an arrangement may eliminate the cylinder head and many parts mounted on the cylinder head.
[0054] The first piston 112 and the second piston 114 at the TDC within the cylinder block 102 may define a combustion chamber 122. The shape of the combustion chamber 122 may be optimized for efficient combustion of air-gaseous fuel mixture in the cylinder block 102. The outer surface of the first piston head 112-1 of the first piston 112 and the second piston head 114-1 of the second piston 114 may be carefully optimized through Computational fluid dynamics (CFD) simulations to facilitate efficient combustion. In addition, the first piston 112 and the second piston 114 may form the walls of the combustion chamber 122 at the TDC. The first piston 112 and the second piston 114 at the BDC may uncover the first port 108-1 and the second port 108-2 enabling the scavenging of the exhaust gases.
[0055] Further, the first piston 112 and the second piston 114 at the TDC may define a stroke volume. The stroke volume may be formed between the first piston 112, the second piston 114, and the cylinder block 102 from the combustion chamber 122. The shape of each piston surface may be customized based on the CFD simulations to achieve efficient combustion of air-gaseous fuel mixture in the cylinder block 102.
[0056] Yet in another embodiment, a first connecting rod 112-2 of the first piston 112 may convert the reciprocating motion of the first piston 112 to the rotary motion of the first crankshaft 116. A second connecting rod 114-2 of the second piston 114 may convert the reciprocating motion of the second piston 114 to the rotary motion of the second crank shaft 118.
[0057] Yet in another embodiment, the cylinder block 102 of the engine 100 may be coupled to the first crank shaft 116 and the second crank shaft 118. Each piston is connected to each crank shaft such that the first piston 112 may be connected to the first crank shaft 116, and the second piston 114 may be connected to the second crank shaft 118. The power generated from the sliding motion of each piston may be delivered to each crank shaft. In addition, the first crank shaft 116 and the second crank shaft 118 may be in communication with an ECU 106 such that the rotation of the first crankshaft 116 and the second crankshaft 118 may be synchronous to other components such as the fuel injector and one or more spark plug assemblies 110-1, 110-2. Further, the first crankshaft 116 may be connected to the second crank shaft 118 through a series of gears such that each piston may move synchronously with the other piston.
[0058] Yet in another embodiment, the second port 108-2 may be operatively coupled between the cylinder block 102 and an exhaust manifold 124. The second port 108-2 may be covered and uncovered upon sliding movement of the first piston 112 at the BDC to enable the opening and closing of the second port 108-2. The second port 108-2 may be configured to transmit the burnt gases accumulated within the cylinder block 102 to the exhaust manifold 124. The second port 108-2 may be opened before the opening of the first port 108-1 such that the burnt gases do not enter the first port 108-1. The size, shape, and number of second port 108-2 may be optimized for effective removal of exhaust gases upon combustion operation from the cylinder block 102.
[0059] Yet in another embodiment, the exhaust manifold 124 of the two-stroke engine 100 may be adapted to collect the exhaust gas from the second port 108-2B and transmit them to exhaust muffler 126.
[0060] Yet in another embodiment, the exhaust muffler 126 may allow the exhaust gases to expand slowly, reducing the noise generated by the sudden release of the exhaust gases from the cylinder block 102 into the exhaust manifold 124, and treating the emissions from the exhaust gases before releasing them into the ambient surroundings.
[0061] Yet in another embodiment, the one or more spark plug assemblies 110-1, 110-2 may be operatively coupled to the fuel injector. Each of the one or more spark plug assemblies 110-1, 110-2 may be configured to pre-ignite the gaseous fuel to form an ignited combustion mixture. The ignited combustion mixture may ignite the air-gaseous fuel mixture within the cylinder block 102 upon compressing the air-gaseous fuel mixture. The first piston 112 and the second piston 114 may be at the TDC to compress the air-gaseous fuel mixture. In an exemplary embodiment, the ignition operation of the air-gaseous fuel mixture within the cylinder block 102 may be selected from a group comprising a conventional spark ignition, a nano-second pulse discharge (NPD) spark plug, and an active pre-combustion chamber ignition device. The nano-second pulse discharge spark may be configured for enhancing the engine’s thermal efficiency by accelerating the ignition process, causing faster flame travel in the combustion chamber 122. Further, the NPD spark plug may ignite leaner air-gaseous fuel mixtures such as hydrogen or any other gaseous fuel blended with hydrogen unlike the conventional spark.
[0062] Yet in another embodiment, a wiring harness 128 may be configured to communicate signals from the ECU 106 with many sensors and actuators on the engine 100.
[0063] Yet in another embodiment, the first port 108-1B can be connected to an intake manifold 130 which supplies intake air into the cylinder block 102 through the first port 108-1B.
[0064] Yet in another embodiment, the first port 108-1 may be operatively coupled between the cylinder block 102 and the fuel injector. The first port 108-1A may be covered and uncovered upon sliding movement of the second piston 114 at the BDC to enable the opening and closing of the first port 108-1A. The first port 108-1A may be configured to inject the air-gaseous fuel mixture into the cylinder block 102 from the fuel injector. The first port 108-1A may be opened after the closing of the second port 108-1B to prevent the air-gaseous fuel mixture do not enter the first port 108-1. The size, geometry, and number of the first port 108-1 may be optimized to burn the air-gaseous fuel mixture completely during the combustion operation.
[0065] Yet in another embodiment, the intake manifold 130 may be configured on the one of the first ports 108-1A and is operatively coupled to the supercharger 132. The intake manifold 130 may include an air filter therewithin, configured to filter the dust particles from the intake air before entering the first port 108-1A such that the dust-free air mixed with the gaseous fuel to form air-gaseous fuel mixture.
[0066] Yet in another embodiment, the supercharger 132 may be configured to receive ambient air from the intake manifold 130 and pressurize the received ambient air to form the air-gaseous fuel mixture. Moreover, the pressurized air forced into the combustion chamber of the cylindrical block 102 may force the exhaust gases out of the cylindrical block 102 through the one or more second ports 108-2A,1082B thereby aiding in the scavenging the exhaust gases. In addition, the supercharger 132 may be in communication with the ECU 106 to pressurize the air as required to synchronize with operating speed and load of the IC engine 100.
[0067] In an exemplary embodiment, the supercharger 132 may be actuated by an electric motor or may be driven directly upon receiving power from the engine 100. In an exemplary embodiment, the one or more fuel injectors may be configured to inject the gaseous fuel into the cylinder block 102 through the at least one of the first port 108-1A,108-1B. A first injector 104-1 may inject fuel at a predefined pressure. The predefined pressure may be between a pressure range of 3 bar to 10 bar. In an exemplary embodiment, the first injector 104-1 may be connected to the first port 108-1 of the cylinder block 102 through a first non-return valve 120-1 or directly based on the location and possible in-cylinder pressures. The first, second, and third fuel injectors 104-1,104-2,104-3 may be controlled by one or more signals received from the ECU 106. The first injector 104-1 may be positioned on the first port 108-1A of the plurality of ports to inject fuel into the cylinder block 102.
[0068] In an exemplary embodiment, the first injector 104-1 positioned on the first port 108-1A of the plurality of ports may be interchangeably referred to as a “port-enabled direct injection (PEDI)” 104-1. The PEDI 104-1 may operate on a concept of direct ignition. The PEDI 104-1 may operate at a low pressure which may be in the range of 3 bar to 8 bar (43.5 psi to 116 psi) compared to other fuel injection systems such that the lower pressure may reduce the load on a fuel pump and other associated components of the IC engine 100, leading to increased reliability and potentially lower manufacturing costs.
[0069] Further, the PEDI 104-1 may deliver fuel directly into the combustion chamber 122 of the cylinder block 102 upon the second piston 114 opening the first port 108-1 while sliding from the BDC to the TDC. The second injector 104-2 positioned adjacent to the first port 108-1A may enable direct injection, and the PEDI 104-1 may also inject the additional fuel into the combustion chamber 122 in a sequel with the fuel injected by the second injector 104-2, such that the low pressure dispensing of the air-gaseous fuel mixture from the PEDI 104-1 may be compensated for maintaining sufficiency of air-gaseous fuel mixture inside the combustion chamber 122 at the time of combustion. Furthermore, the PEDI 104-1 and the second injector 104-2 may be capable of delivering precise amounts of fuels into the combustion chamber at an optimal timing, based on various IC engine 100 operating parameters such as an engine speed, a load, and a temperature optimizing the fuel efficiency and reducing emissions of the proposed two- stroke engine 100. Furthermore, the PEDI 104-1 may be selected from any commercially-available port fuel injector.
[0070] In an embodiment, the second injector 104-2 may be configured on the cylinder block 102 (adjacently located to the first port 108-1A) to compensate for the deficient fuel required that may not be injected by the first injector 104-1. The second injector 104-2 may be configured in a predefined orientation such that the fuel may be injected into the cylinder block 102 in addition to the fuel which was already injected as shown in FIG. 1A. The first injector 104-1 or the second injector 104-2 or both may be used based on the fuel requirements of the engine 100.
[0071] In another exemplary embodiment, the second injector 104-2 of the one or more fuel injectors may be configured on the at least one of the plurality of ports for injecting fuel into the cylinder block 102. The second injector 104-2 may compensate the combustion chamber 122 with enough fuel which may not be compensated by the first injector 104-1. The location, orientation, and direction of the first injector 104-1 and the second injector 104-2 may be optimized based on CFD simulations to prevent the air-gaseous fuel mixture from entering the second port 108-2 of the cylinder block 102. In another exemplary embodiment, the required amount of fuel may be injected using the one or more fuel injectors each configured on the plurality of ports.
[0072] Yet in another embodiment, the ECU 106 may be configured to communicate with a plurality of sensors associated with the two-stroke engine 100.The ECU 106 may be configured to analyse the pressure of intake air, the temperature of intake air, the temperature of the engine 100, throttle position, etc., and may correspondingly transmit one or more signals to fuel injectors, spark plugs assemblies, etc.
[0073] Yet in another exemplary embodiment, the gaseous fuels of blends of hydrogen, CNG, ammonia, and biogas may be stored in a fuel tank 134. In addition, a pressure regulator 136 may regulate the pressure of fuel supplied to the engine 100. The pressure regulator 136 may reduce the pressure of gaseous fuel stored in the fuel tank 134 to a required level, and supply to the two-stroke engine 100. The pressure regulator 136 may be configured to regulate the pressure of the air-gaseous fuel mixture which is flowing downstream of the regulator independent of the pressure variations on the upstream of the regulator. The downstream pressure may be pressure of the air-fuel leaving the pressure regulator 136. The upstream pressure may be pressure of the air-fuel entering the pressure regulator 136. Further, a fuel pipe 138 may be configured to supply gaseous fuel from the fuel tank 134 to the two-stroke IC engine 100.
[0074] In an embodiment, the proposed gas-fuelled two-stroke IC engine 100 with opposed pistons with reduced parts when compared to the conventional four-stroke IC engine is described. The reduced parts may result in reduction of heat to be dissipated from the cylinder block 102. The thermal efficiency of the engine 100 may be based on the size and shape of the cylinder head. The proposed gas-fuelled two-stroke IC engine 100 with opposed pistons may eliminate the cylinder head which contributes to heat reduction. The amount of heat to be dissipated may be considerably reduced for the same cylinder volume, which may result in higher thermal efficiency.
[0075] In addition, the proposed gas-fuelled two-stroke IC engine 100 with opposed pistons may operate based on a two-stroke Otto cycle. The two-stroke Otto cycle may be adapted to produce one power stroke per revolution of crankshaft. The air exchange may be through the first port 108-1 and the second port 108-2. The opening and closing of each port may be actuated by the sliding movement of the first piston 112 and the second piston 114 between the TDC and BDC instead of valves. The opening and closing of each port may replace the burnt gases with fresh air. The fresh air may be pressurized by the supercharger 132 through the first port 108-1. Moreover, the conventional IC engines may use camshafts to operate the valves. The camshafts may be powered by crankshafts, thereby consuming a considerable power generated by the engines. The proposed gas-fuelled two-stroke IC engine 100 with opposed pistons may eliminate the valves, the camshafts, and the associated drive to enhance the efficiency of the proposed two-stroke IC engine 100.
[0076] Referring to FIG. 2, each of the spark plug assemblies 110-1, 110-2 with a pre-combustion chamber for ignition of ultra-lean air-gaseous fuel mixture is described. The spark plug assembly 110 may include a spark plug 110B, a pre-combustion chamber 110A, a second non-return valve 120-2, and a baffle 110C. In an exemplary embodiment, the spark plug 110B may be a Nano-second pulse discharge spark plug. The spark plug assembly 110 may be configured to operate on the concept of direct ignition where a smaller quantity of the gaseous fuel is pre-ignited in the pre-combustion chamber 110A or a smaller combustion capsule. The pre-combustion chamber 110A may be associated with the spark plug assembly 110 forming a part of the assembly 100. The pre-ignition of gaseous fuel may be received into the pre-combustion chamber 110A from a third fuel injector 104-3 through the second non-return valve 120-2, preventing the pre-ignited fuel from returning into the third fuel injector 104-3. The pre-combustion chamber 110A may receive air from the combustion chamber 122 of the cylinder block 102 such that the injected one or more gaseous fuels mix with the air to form an air-gaseous fuel mixture therewithin. The pre-ignition of the air-gaseous fuel mixture may form an ignited combustion mixture. A jet of ignited combustion mixture may be forced into the cylinder block 102 through the baffle 110C to ignite the air-gaseous fuel mixture. The jet of ignited combustion mixture passing through the baffle 110C may generate a flame which may be spread evenly within the combustion chamber 122 of the cylinder block 102. This flame may enable multiple ignitions of the air-gaseous fuel mixture at different locations within combustion chamber 122. The multiple ignitions may reduce the time of ignition of the air-gaseous fuel mixture, thereby increasing the efficiency of the proposed two-stroke engine 100.
[0077] In addition, the spark plug assembly 110 may be in communication with the ECU 106. The spark plug assembly 110 may be configured to control the quantity of fuel injected in the pre-combustion chamber 110A and the combustion chamber 122, such that different equivalence ratios for the pre-combustion chamber 110A and the combustion chamber 122 of the cylinder block 102 may be controlled.
[0078] Further, the lean air-gaseous fuel mixture when pressured at high pressure in the pre-combustion chamber 110A may be configured to ignite the air-gaseous fuel mixture in the combustion chamber 122 of the cylinder block 102 such that the air-gaseous fuel mixture upon ignition may push the first piston 112 and the second piston 114 positioned at TDC, away from each other towards the BDC. The pushing of the first piston 112 may rotate the first crankshaft 116 through the first connecting rod 112-2. The pushing of the second piston 114 may rotate the second crankshaft 118 through the second connecting rod 114-2. Further, the second port 108-2 of the one or more ports may be opened upon the first piston 112 reaching the BDC to let-out the exhaust gases from the cylinder block 102 into the exhaust manifold 124. The second piston 114 upon reaching the TDC may open the second port 108-2 and close the first port 108-1 to receive the fuel from the fuel injector 104 for combustion operation. The process may be repeated in cycles enabling the two stoke engine 100 to rotate the first crankshaft 116 and the second crankshaft 118.
[0079] In an exemplary embodiment, the conventional spark plug may be used to ignite the air-gaseous fuel mixture in the combustion chamber 122. In another exemplary embodiment, the nano-second pulse discharge (NPD) spark plug may be used to ignite the air-gaseous fuel mixture in the combustion chamber 122. The NPD spark plug may be configured to accelerate the ignition process. In addition, the NPD spark plug may ignite leaner air-gaseous fuel mixtures such as gaseous hydrogen or any other gaseous fuel blended with gaseous hydrogen, unlike the conventional spark plug. Further, the NPD spark plug may enhance the engine’s thermal efficiency of the IC engine compared to the conventional spark plug.
[0080] In another embodiment, the properties of gaseous fuels as shown in the table below illustrate the comparison of gasoline with CNG, hydrogen, and ammonia gas. Hydrogen has very high flame speeds and a huge range of flammability limits which can ignite faster and have higher in-cylinder pressures resulting in higher thermal efficiencies. Similar advantages may be found with CNG though not to the extent of hydrogen. The use of gaseous fuels in a spark-ignited engine results in enhanced thermal efficiency. Biogas may be a renewable fuel produced from many sources such as biomass, household waste, etc. The use of biogas can reduce greenhouse gas emissions by cutting down fossil fuel usage.
Property Gasoline CNG Hydrogen Ammonia
Lower calorific value (MJ/kg) 45 47.5 130 18.6
Stoichiometric air-fuel ratio (%w/w) 14.7 17.2 34.3 6
Laminar flame speed @ NTP (cm/s) 28 41 190 7
Flammability limits (%v/v) 1.4-7.6 5-15 4-75 15-28

[0081] In an exemplary embodiment, the proposed two-stroke IC engine 100 may be used in unmanned aerial vehicles (UAV), two-wheelers, three-wheelers, range extenders for hybrid vehicles, and power generators.
[0082] Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “top”, “bottom” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the FIGs. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the FIGs. For example, if the device in the figures is turned over, elements described as “under”, or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” may encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
[0083] Herein, the terms “attached”, “connected”, “interconnected”, “contacting”, “mounted”, “coupled” and the like can mean either direct or indirect attachment or contact between elements unless stated otherwise.
[0084] Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items.
[0085] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including” when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
[0086] While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications may be made, and that many changes may be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

ADVANTAGES OF THE PRESENT DISCLOSURE
[0087] The present disclosure provides a simple, compact, and efficient gas-fuelled two-stroke internal combustion engine with opposed pistons operable using gaseous fuels.
[0088] The present disclosure provides a two-stroke IC engine with stroke volume ranging from 20 cc to 500 cc.
[0089] The present disclosure provides a two-stroke IC engine with maximum scavenging efficiency.
[0090] The present disclosure provides a two-stroke IC engine where fuel is injected at low pressure.
[0091] The present disclosure provides a low-pressure port fuel injector at an intake port that may be oriented in a manner such that upon uncovering of the intake port by a piston, the fuel is injected directly into a cylinder block.
[0092] The present disclosure provides a two-stroke IC engine that uses an ignited combustion mixture in combination with one or more electrical impulses to ignite the fuel in the cylinder block.
[0093] The present disclosure provides a two-stoke IC engine that uses any blend of hydrogen, compressed natural gas (CNG), ammonia, and biogas.
[0094] The present disclosure provides a two-stroke IC engine that uses one or more spark plugs and one or more fuel injectors actuated by an electronic control unit (ECU) to improve fuel efficiency of the two-stroke IC engine.

REFERENCE NUMERALS
PARTICULARS REFERRAL NUMERAL
Two-stroke engine 100
Cylinder block 102
Fuel injectors 104
First injector 104-1
Second injector 104-2
Third fuel injector 104-3
Electronic Control Unit (ECU) 106
First ports 108-1A, 108-1B
Second ports 108-2A, 108-2B
Spark plug assemblies 110-1,110-2
Pre-combustion Chamber 110A
Spark plug 110B
Baffle 110C
First piston 112
First piston head 112-1
First connecting rod 112-2
Second piston 114
Second piston head 114-1
Second connecting rod 114-2
First crank shaft 116
Second crank shaft 118
First non-return valve 120-1
Second non-return valve 120-2
Combustion chamber 122
Exhaust manifold 124
Exhaust muffler 126
Wire harness 128
Intake manifold 130
Supercharger 132
Fuel tank 134
Pressure regulator 136
Fuel pipe 138
,CLAIMS:1. A two-stroke internal combustion (IC) engine (100) operable on gaseous fuels, the two-stroke IC engine (100) comprising:
a cylinder block (102) comprising opposed pistons that comprise a first piston (112) and a second piston (114) slidably disposed therewithin such that a first piston head (112-1) of the first piston (112) slides towards and away from a second piston head (114-1) of the second piston (114) upon combustion of a mixture of air and one or more gaseous fuels that correspond to any combination of blends of hydrogen, compressed natural gas (CNG), ammonia, and biogas within the cylinder block (102),
wherein the gaseous fuel is injected into the cylinder block (102) through a first injector (port enabled direct injection (PEDI)) (104-1) and a second fuel injector (106) such that:
the first injector (104-1), which is a low-pressure port fuel injector configured on one or more first ports (108-1A, 108-1B) of the cylinder block (102) in an angular orientation, injects a specific quantity of gaseous fuel at low pressure from the one or more first ports (108-1A, 108-1B) into a combustion chamber of the cylinder block (102), before the first piston head (112-1) covers the one or more first ports (108-1A, 108-1B) upon sliding from a Bottom Dead Center (BDC) to a Top Dead Center (TDC), and
the second injector (104-2), directly configured on the cylinder block (102), located adjacent to the first port (108-1A), injects a remaining quantity of gaseous fuel into the cylinder block (102) for combustion process as a sequel to the first gas injector (106), before the first piston head (112-1) covers mouth of the second injector (104-2) upon sliding from the BDC to the TDC, such that the deficiency of the gaseous fuel dispensed from the first injector (104-1) is compensated and a sufficiency of an air-gaseous fuel mixture is maintained within the combustion chamber during the combustion process,
wherein the air-gaseous fuel mixture formed within the cylinder block (102) gets ignited by plasma generated by one or more spark plug assemblies (110-1, 110-2) within the combustion chamber of the cylinder block (102), resulting in sliding of the opposed pistons, thereby enhancing thermal efficiency of the two-stroke IC engine (100).

2. The two-stroke IC engine (100) as claimed in claim 1, the gaseous fuel injected into the cylinder block (102) through the first injector (104-1) and the second injector (104-2) are instantly ignited within the cylinder block (102) through one or more electrical pulses generated by at least one spark plug assembly of the one or more spark plug assemblies (110-1, 110-2), to enable the first piston (112) to slide between a medial portion of the cylinder block (102) and the TDC, and the second piston (114) to slide between the medial portion and the BDC for enhancing thermal efficiency of the two-stroke IC engine (100).

3. The two-stroke IC engine (100) as claimed in claim 1, the one or more spark plug assemblies (110-1, 110-2) are directly configured on a cylindrical portion of the cylinder block (102), wherein a nanosecond pulse discharged plasma, generated by one of the one or more spark plug assemblies (110-1, 110-2) in combination with the one or more electrical pulses generated by other spark plug assemblies (110-1, 110-2) into the cylinder block (102), wherein said combination instantaneously ignites the air-gaseous fuel mixture within the cylinder block (102).

4. The two-stroke IC engine (100) as claimed in claim 3, comprises an electronic control unit (ECU) (106) in communication with the first injector (104-1), the second injector (104-2), and the one or more spark plug assemblies (110-1, 110-2), wherein the ECU (106) is configured for:
injecting a required quantity of the gaseous fuel into the cylinder block (102) by actuating the first injector (104-1) and then the second injector (104-2); and
generating the required plasma and electric pulses for enabling combustion of the air-gaseous fuel mixture within the cylinder block (102) using the one or more spark plug assemblies (110-1, 110-2).

5. The two-stroke IC engine (100) as claimed in claim 3, wherein at least one spark plug assembly of the one or more spark plug assemblies (110-1, 110-2) comprises:
a pre-combustion chamber (110A) adapted to receive a mixture of the air and the one or more gaseous fuels;
a third injector (104-3) of the one or more fuel injectors in fluidic communication with the pre-combustion chamber (110A), wherein the third injector (104-3) is adapted to inject the gaseous fuel into the pre-combustion chamber (110A), upon receiving ambient air and the one or more gaseous fuels from a fuel tank (134); and
a spark plug (110B) electrically coupled to the pre-combustion chamber (110A), wherein the spark plug (110B) is adapted to ignite the air-gaseous fuel mixture in the pre-combustion chamber for creating hot burning gas that enters into the combustion chamber (122) of the cylinder block (102) and ignites the resulting air-gaseous fuel mixture in the combustion chamber (122).

6. The two-stroke IC engine (100) as claimed in claim 5, wherein an ECU (106) is configured for:
injecting a required quantity of the gaseous fuel into the pre-combustion chamber (110A) by using a third injector (104-3); and
generating required sparks for igniting an air-gaseous fuel mixture that is formed upon injected gaseous fuel being mixed with resulting air available therewithin, in the pre-combustion chamber (110A) using the spark plug (110B).

7. The two-stroke IC engine (100) as claimed in claim 1, wherein the one or more first ports (108-1A) housing the first injector (104-1) therewithin are coupled to a supercharger (132) of the two stroke IC engine (100) such that the one or more first ports (108-1A) are adapted to receive air compressed by the supercharger (132) along with the one or more gaseous fuels from the first injector (104-1) facilities injection of the one or more gaseous fuels along with the air into the cylinder block (102).

8. The two-stroke IC engine (100) as claimed in claim 1, wherein the cylinder block (102) comprises one or more second ports (108-2A, 108-2B) for scavenging exhaust gases from the combustion chamber of the cylinder block (102).

9. The two-stroke IC engine (100) as claimed in claim 9, wherein exhaust gases within the cylinder block (102) are scavenged out from the cylinder block (102) through the one or more second ports (108-2A, 108-2B) when the gaseous fuel is sprayed into the cylinder block (102) through the one port (108-1A) of the one or more first ports (108-1A, 108-1B).

10. The two-stroke IC engine (100) as claimed in claim 1, wherein the two-stroke IC engine (100) comprises:
a first crank shaft (116) coupled to the first piston (112), said first crank shaft (116) is configured within the cylinder block (102), wherein the first crank shaft (116) is adapted to convert a horizontal movement of the first piston (112) into a rotational movement; and
a second crank shaft (118) coupled to the second piston (114), said second crank shaft (118) is configured within the cylinder block (102) to convert a horizontal movement of the second piston (114) into a rotational movement.

11. The two-stroke IC engine (100) as claimed in claim 1, wherein the first piston (112) and the second piston (114) define a predefined stroke volume within the cylinder block (102), wherein the predefined stroke volume is between a range of 20 cc to 500 cc.
12. The two-stroke IC engine (100) as claimed in claim 1, wherein the predefined pressure of the one or more gaseous fuels correspond to a range between 3 bar to 10 bar.

13. The two-stroke IC engine (100) as claimed in claim 1, wherein the two-stroke engine (100) comprises a second non-return valve (120-2) configured between each of the third injector (104-3) and the one or more spark plug assemblies (110-1, 110-2) for preventing back flow of the one or more gaseous fuels into the third injector (104-3).