FORM 2
THE PATENTS ACT, 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A PISTON FOR AN ENGINE”
Name and Address of the Applicant:
TATA MOTORS LIMITED of Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai - 400 001 Maharashtra, India.
Nationality: Indian
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
[001] The present disclosure relates to the field of automobiles. Particularly, but not exclusively, the present disclosure relates to an internal combustion engine for a vehicle. Further, embodiments of the present disclosure disclose a piston of the engine for the vehicle.
BACKGROUND OF THE DISCLOSURE
[002] Generally, vehicles include a drive train with a prime mover, such as an internal combustion engine to deliver necessary power for driving the vehicle. The internal combustion engines include a number of cylinders, and each cylinder defines a combustion chamber. The combustion chamber is adapted to receive a piston, which is connected to a connecting rod by a piston pin. The piston is subjected to high pressure and high temperature due to combustion of charge being injected into the combustion chamber, where the piston is configured to convert a combustion energy into mechanical energy by way of reciprocating in the cylinder. Generally, the piston includes a head portion and a skirt portion, wherein the head portion of the piston is exposed to said high pressure generated during combustion, while the skirt portion transfers the force/load to a crankshaft of the engine by means of the piston pin and the connecting rod.
[003] With advent of technology, to improve performance of the engine, various attempts have been made to modify configuration of myriad of components of said engine. One such modification in convention is of the piston, where the piston is either made of steel or aluminum alloys. The aluminum alloy piston is known for higher heat dissipation, however, the aluminum alloy piston, in general, are considered to exhibit lower thermal efficiency and lower peak firing pressure limit. On the other hand, in the steel piston, due to higher temperature attained on the piston during combustion, especially near the grooves, there may be a possibility of oil coking within the cylinder body. Further, weight of such steel piston is considerably high which may affect fuel efficiency of the vehicle. To overcome such limitations, further attempts have been made to modify the piston with bi-material, i.e., in convention, the head portion and skirt portion of the piston are made of different material and joined together by way of fastening or bonding. However, weight of the piston and possibility of oil coking are still concern during operation of the engine.
[004] The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the aspect of piston of the engine for the vehicle.
SUMMARY OF THE DISCLOSURE

[005] One or more shortcomings of the conventional piston is overcome by a piston of an engine for a vehicle, as described. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
[006] In a non-limiting embodiment of the disclosure, a piston of an engine for a vehicle is disclosed. The piston includes a first body structure disposable in a cylindrical section of the engine. The first body structure includes a head portion defined with a central cavity and a skirt portion downwardly extending from the head portion. The piston further includes a second body structure configured to seat in a portion of the first body structure. The second body structure includes a projection portion extending into the central cavity along the head portion and the skirt portion. The first body structure and the second body structure are made of dissimilar material.
[007] In an embodiment, the first body structure is made of a first material including at least one of an alloy and a metal, preferably aluminum, and the second body structure is made of a second material including at least one of an alloy and a metal, preferably steel.
[008] In an embodiment, the first body structure comprises a plurality of primary through holes and the second body structure comprises a plurality of secondary through holes, and wherein the plurality of primary through holes and the plurality of secondary through holes are co-axially aligned.
[009] In an embodiment, the first body structure comprises a shoulder portion extending from an internal surface of the first body structure to intrude into the central cavity, wherein the shoulder portion is configured to abut and accommodate at least a portion of the second body structure.
[0010] In an embodiment, the first body structure is defined with at least one channel configured to radially surround at least a portion of the second body structure.
[0011] In an embodiment, the first body structure is defined with at least two grooves, along an outer periphery of the head portion of the first body structure, configured to accommodate at least one piston ring.
[0012] In an embodiment, the second body structure is integrally formed on the first body structure.
[0013] In an embodiment, the top surface of the second body structure is defined with pre-defined shape.

[0014] In another non-limiting embodiment of the disclosure, an engine for a vehicle is disclosed. The engine includes a cylinder body defining a cylindrical section of the engine. The engine further includes a cylinder head receivable by the cylinder body, the cylinder head comprises means for fuel supply. Furthermore, the engine includes a piston operatively displaceable in the cylinder body. The piston includes a first body structure disposable in a cylindrical section of the engine. The first body structure includes a head portion defined with a central cavity and a skirt portion downwardly extending from the head portion. The piston further includes a second body structure configured to seat in a portion of the first body structure. The second body structure includes a projection portion extending into the central cavity along the head portion and the skirt portion. The first body structure and the second body structure are made of dissimilar material, and the first and the second structures are joined to form a unified structure. In addition, the engine includes a piston pin and a crankshaft. The piston pin is receivable by the skirt portion of the first body structure and the projection portion of the second body structure. The crankshaft rotatably disposed in the engine, coupled to the piston pin. Also, the engine includes a connecting rod connectable to the piston through the piston pin at one end and connectable to the crankshaft at the other end, wherein the crankshaft is configured to rotate on displacement of the piston in the cylinder body.
[0015] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0016] The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
[0017] Figure 1 illustrates a perspective view of the piston of Figure 1, according to an embodiment of the present disclosure.

[0018] Figure 2 illustrates a front cross-sectional view of a piston of an engine for a vehicle according to an embodiment of the present disclosure.
[0019] Figure 3 illustrates a side cross-sectional view of the piston of Figure 1 according to an embodiment of the present disclosure.
[0020] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the device and the system illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0021] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by the way of example in the figures and will be described below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[0022] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of the piston or the engine, without departing from the scope of the disclosure. Therefore, such modifications are considered to be part of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein. Also, the piston and the engine of the present disclosure may be employed in any kind of vehicles including commercial vehicles, passenger vehicles, two-wheeled vehicles, three-wheeled vehicles, and among others. However, neither the vehicle nor complete engine of the vehicle is illustrated in the drawings of the disclosure is for the purpose of simplicity.
[0023] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover non-exclusive inclusions, such that a device, assembly, mechanism, system, and method that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system/assembly proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the device or system.

[0024] Embodiments of the present disclosure discloses a piston of an engine for a vehicle. The piston includes a first body structure disposable in a cylindrical section of the engine. The first body structure includes a head portion defined with a central cavity and a skirt portion downwardly extending from the head portion. The piston further includes a second body structure configured to seat in a portion of the first body structure. The second body structure includes a projection portion extending into the central cavity along the head portion and the skirt portion. The first body structure and the second body structure are made of dissimilar material. Such piston may sustain high pressure and ensure maximum efficiency with minimum weight.
[0025] The following paragraphs describe the present disclosure with reference to Figures. 1 to 3. In the figures, the same element or elements which have similar functions are indicated by the same reference signs. With general reference to the drawings, the piston of the engine for the vehicle is illustrated and generally identified with reference numeral (100). The piston (100) may be operatively associated with an engine [not shown] for a vehicle [not shown]. It will be understood that the teachings of the present disclosure are not limited to any particular vehicle. The engine includes a cylinder body defining a cylindrical section of the engine. The engine further includes a cylinder head receivable by the cylinder body, the cylinder head comprises means for fuel supply. The fuel may be at least one of air, petrol, diesel, gasoline, liquid petroleum gas, hydrogen, and among others.
[0026] Furthermore, the engine includes a piston (100) operatively displaceable in the cylinder body. As illustrated in Figures 1-3, the piston (100) includes a first body structure (2) disposable in a cylindrical section of the engine. The first body structure (2) includes a head portion (6) defined with a central cavity (12) and a skirt portion (8) downwardly extending from the head portion (6). The piston (100) further includes a second body structure (4) configured to seat in a portion of the first body structure (2). The second body structure (4) includes a projection portion (14) extending into the central cavity (12) along the head portion (6) and the skirt portion (8). The first body structure (2) and the second body structure (4) are made of dissimilar material. In addition, the engine includes a piston pin, a connecting rod, and a crankshaft. The piston pin is receivable by the skirt portion (8) of the first body structure (2) and the projection portion (14) of the second body structure (4). Also, the engine includes a connecting rod connectable to the piston (100) through the piston pin at one end and connectable to the crankshaft at the other end, wherein the crankshaft is configured to rotate on displacement of the piston (100) in the cylinder body.

[0027] The piston (100), due to combustion of fuel within the cylinder body, is subjected to high pressure which results in reciprocating motion of the piston (100). Such reciprocating motion of the piston (100) is transferred to the crankshaft as a rotary motion through the piston pin and connecting rod. The rotary motion of the crankshaft may be further used for at least one of driving the vehicle, charging the battery of the vehicle, etc.
[0028] Figures. 2 and 3 illustrate a front cross-sectional view of a piston (100) of an engine for a vehicle and a side cross-sectional view of the piston (100), respectively, according to an embodiment of the present disclosure. The piston (100) includes a first body structure (2) disposable in a cylindrical section of the engine (also referred to as a combustion chamber defined in each cylinder) of the engine. The first body structure (2) includes a head portion (6) which is defined with a central cavity (12), and a skirt portion (8) downwardly extending from the head portion (6). The skirt portion (8) may include opposing thrust surfaces (8a) configured to contact the inner wall of the cylinder body of the engine. The piston (100) further includes a second body structure (4) configured to seat in a portion of the first body structure (2). The second body structure (4) includes a projection portion (14) extending into the central cavity (12) along the head portion (6) and the skirt portion (8). The projection portion (14) of the second body structure (4) ensures structural durability of the piston (100) by taking the combustion load and transferring further to the piston pin and the connecting rod.
[0029] Furthermore, the first body structure (2) and the second body structure (4) are made of dissimilar material. In an embodiment, the first body structure (2) is made of a first material including at least one of an alloy and a metal, and the first material may be aluminum. The aluminum may be in the alloy form by alloying aluminum with at least one of silicon, copper, nickel, magnesium, and among others. The second body structure (4) is made of a second material including at least one of an alloy and a metal, and the second material may be steel. The second material may be one of stainless steel, low-carbon steel, high strength steel, and among others. The second body structure (4) of the piston (100) exhibits low thermal conductivity, thereby ensuring minimum thermal losses. Also, the first body structure (2) reduces weight of the piston (100) and enables rapid heat dissipation. Moreover, such configuration of the piston (100) can sustain high pressure and ensures maximum efficiency with minimum weight.
[0030] The first body structure (2) of the piston (100) comprises a plurality of primary through holes (10). Further, the second body structure (4) of the piston (100) comprises a plurality of secondary through holes (16). The plurality of primary through holes (10) and the plurality of

secondary through holes (16) are co-axially aligned during integration of the second body structure (4) with the first body structure (2). In one embodiment, the plurality of primary through holes (10) and the plurality of secondary through holes (16) may receive a piston pin [not shown in figures]. The piston pin is configured to connect the piston (100) with the connecting rod. In an illustrative embodiment as depicted in Figure 1, the first body structure (2) includes four projection portions (14), in which two projection portions (14) are defined with the plurality of primary through holes (10). Further, the second body structure (4) includes two projection portions (14) defined with the plurality of secondary through holes (16). The two projection portions (14) of the first body structure (2) defined with the plurality of primary through holes (10) and the two projection portions (14) of the second body structure (4) defined with the plurality of secondary through holes (16) are co-axially aligned during integration of the second body structure (4) with the first body structure (2). Furthermore, the piston pin is receivable within the plurality of primary through holes (10) and the plurality of secondary through holes (16).
[0031] The second body structure (4) is integrally formed on the first body structure (2) as depicted in Figure 1 using at least one of a bonding agent, a special casting process such as a hybrid casting or a compound casting. Also, the top surface of the second body structure (4) may be substantially flat or may be defined with pre-defined shape. In an illustrative embodiment, as depicted in Figures 1-3, the top surface of the second body structure (4) is defined with a bowl-shaped profile. Further, the second body structure (4) may include a flange (4a) positioned below an outer periphery of the top surface of the second body structure (4). In addition, the pre-defined shape defined on the top surface of the second body structure (4) may be a semi-spherical shape, a crown shape, a tapered profile, a concave profile, etc, depending on the type of fuel used for combustion. However, such pre-defined shapes cannot be considered as limitation to the present disclosure, rather, any other shape may be possible within the scope of the present disclosure. Such profile defined on top surface of the second body structure (4) is configured to expose to high pressure generated during combustion. Moreover, the profile defined on top surface of the second body structure (4) is not only configured to sustain high pressure, but also to provide low thermal conductivity and thereby reducing thermal losses. Furthermore, the first body structure (2) may be manufactured by casting and machining. The second body structure (4) may be manufactured by forging and machining and the second body structure (4) is joined with the first body structure (2) to form an integrated structure. However, the first body structure (2) and the second body structure (4) may be manufactured by any other manufacturing methods with which the first (2) and the

second body structures (4) may be integrally formed, without deviating from the scope of the present disclosure. Such configuration of the piston mitigates disassembly of the first (2) and the second body structures (4) due to operating pressure or temperature within the cylinder of the engine.
[0032] In an embodiment, the profile shapes are pre-defined and are dependent on type of the fuel used for combustion. The top surface of the second body structure (4) including the profile are exposed to high temperature and pressure during combustion. In an illustrative embodiment as depicted in figures 1-3, the top surface of the second body structure (4) including the profile are maintained in steel material to provide lower thermal conductivity and to sustain high pressure.
[0033] The first body structure (2) further includes a shoulder portion (22) extending from an internal surface (24) of the first body structure (2) to intrude into the central cavity (12). Such intrusion from the internal surface (24) of the first body structure (2) may be at least 5% laterally into the central cavity (12). The shoulder portion (22) is configured to abut and accommodate at least a portion of the second body structure (4). The shoulder portion (22) provides rigid support to the second body structure during high pressure combustion. Further, the shoulder portion (22) mitigates the possibility of shearing of the flange (4a) in top portion of the second body structure (4). Furthermore, such configuration of the shoulder portion (22) relieves stress concentration at the portion where the second body structure (4) is formed on the first body structure (2). In an embodiment, the first body structure (2) may include more than one shoulder portion (22). In an embodiment, the piston (100) in which the top surface of the second body structure (4) is substantially flat, may not include the shoulder portion (22).
[0034] The first body structure (2) may include at least two grooves (20) defined along an outer periphery of the head portion (6) of the first body structure (2). Each of the at least two grooves (20) is configured to accommodate at least one piston ring. In an illustrative embodiment as depicted in Figures 1-3, the first body structure (2) may include two grooves (20) having different depth, in which one groove is configured to accommodate a compression ring and another groove is configured to accommodate an oil ring. The at least two grooves (20), being formed in the first body structure (2) made of aluminium, ensures rapid heat transfer during reciprocating of the piston (100), thereby mitigating oil coking and thereby, achieving better durability of the piston (100).
[0035] The first body structure (2) may include at least one channel (18) configured to radially surround at least a portion of the first body structure (2) and defined proximal to the second

body structure (4). The at least one channel (18) may surround entire circumference of the first body structure (2) or may be defined as a plurality of segregated channels radially surrounding at least a portion of the first body structure (2). Further, the at least one channel (18) may be positioned proximal to the top surface of the second body structure (4) or side surface (26) of the second body structure (4). In an illustrative embodiment as depicted in Figures 1-3, the channel (18) is positioned proximal to the top surface of the second body structure (4) and side surface (26) of the second body structure (4). The at least one channel (18) may be configured to accommodate a coolant to absorb heat generated by combustion from the first body structure (2). The coolant may be including, water, oil, or any coolant with or without suspended material such as micro/nano particles, or among other material. In an embodiment, the coolant may be in solid state or liquid state or combination thereof. For instance, the coolant may be in solid state in the absence of heat and may melt into liquid state upon absorbing heat from the first body structure (2) during combustion. In an illustrative embodiment, the coolant is engine oil. Further, the coolant may absorb the heat from the first body structure (2) which is being discharged/transferred from the top surface of the second body structure (4) or side surface (26) of the second body structure (4) or combination thereof.
[0036] The piston (100) of the present disclosure can sustain high pressure and ensures maximum efficiency with minimum weight. Further, the second body structure (4) of the piston (100) exhibits low thermal conductivity, thereby ensuring minimum thermal losses. The channel (18) being defined in the first body structure (2) enables faster heat dissipation. The at least two grooves (20) ensures rapid heat transfer, thereby mitigating oil coking and hence, achieving better durability of the piston (100). The projection portion (14) of the second body structure (4) ensures structural durability of the piston (100) by taking the combustion load and transferring further to the piston pin and the connecting rod. Furthermore, configuration of the piston (100) of the present disclosure facilitates the skirt portion (8) to be made with minimum length, thereby ensuring minimum friction. In addition, the piston (100) enhances noise, vibration, and harshness (NVH) properties, reduces wastage of friction power, and reduces inertia forces.
[0037] It is to be understood that a person of ordinary skill in the art may develop a piston (100) of similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.

EQUIVALENTS
[0038] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0039] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
[0040] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
[0041] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense

one having skill in the art would understand the convention (e.g., “a piston (100)) having at least one of A, B, and C” would include but not be limited to device that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a piston (100) having at least one of A, B, or C” would include but not be limited to pistons that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

REFERRAL NUMERICALS

Numerical Particulars
2 First body structure
4 Second body structure
4a Flange
6 Head portion
8 Skirt portion
10 Plurality of primary through holes
12 Central cavity
14 Projection portion
16 Plurality of secondary through holes
18 Channel
20 Groove
22 Shoulder portion
24 Internal surface of the first body structure
26 Side surface of the second body structure
100 Piston

We claim:
1. A piston (100) of an engine for a vehicle, the piston (100) comprising:
a first body structure (2) disposable in a cylindrical section of the engine, the first body structure (2) comprises:
a head portion (6) defined with a central cavity (12); and
a skirt portion (8) downwardly extending from the head portion (6); and a second body structure (4) configured to seat in a portion of the first body structure (2), the second body structure (4) comprises a projection portion (14) extending into the central cavity (12) along the head portion (6) and the skirt portion (8);
wherein, the first body structure (2) and the second body structure (4) are made of dissimilar material.
2. The piston (100) as claimed in claim 1, wherein the first body structure (2) is made of a first material including at least one of an alloy and a metal, preferably aluminum.
3. The piston (100) as claimed in claim 1, wherein the second body structure (4) is made of a second material including at least one of an alloy and a metal, preferably steel.
4. The piston (100) as claimed in claim 1, wherein the first body structure (2) comprises a plurality of primary through holes (10) and the second body structure (4) comprises a plurality of secondary through holes (16), wherein the plurality of primary through holes (10) and the plurality of secondary through holes (16) are co-axially aligned.
5. The piston (100) as claimed in claim 1, wherein the first body structure (2) comprises a shoulder portion (22) extending from an internal surface (24) of the first body structure (2) to intrude into the central cavity (12), wherein the shoulder portion (22) is configured to abut and accommodate at least a portion of the second body structure (4).
6. The piston (100) as claimed in claim 1, wherein the first body structure (2) is defined with at least one channel (18) configured to radially surround at least a portion of the second body structure (4).
7. The piston (100) as claimed in claim 1, wherein the first body structure (2) is defined
with at least two grooves (20), along an outer periphery of the head portion (6) of the
first body structure (2), configured to accommodate at least one piston ring.

8. The piston (100) as claimed in claim 1, wherein the second body structure (4) is integrally formed on the first body structure (2).
9. The piston (100) as claimed in claim 1, wherein the top surface of the second body structure (4) is defined with pre-defined shape.
10. An engine comprising:
a cylinder body defining a cylindrical section of the engine;
a cylinder head receivable by the cylinder body, the cylinder head comprises means for fuel supply;
a piston (100) operatively displaceable in the cylinder body, the piston (100) comprising:
a first body structure (2) disposable in a cylindrical section of the engine, the first body structure (2) comprises:
a head portion (6) defined with a central cavity (12); and a skirt portion (8) downwardly extending from the head portion (6); and
a second body structure (4) configured to seat in a portion of the first body structure (2), the second body structure (4) comprises a projection portion (14) extending into the central cavity (12) along the head portion (6) and the skirt portion (8);
wherein, the first body structure (2) and the second body structure (4) are made of dissimilar material;
a piston pin receivable by the skirt portion (8) of the first body structure (2) and the projection portion (14) of the second body structure (4);
a crankshaft rotatably disposed in the engine, coupled to the piston pin; and a connecting rod connectable to the piston through the piston pin at one end and connectable to the crankshaft at the other end, wherein the crankshaft is configured to rotate on displacement of the piston in the cylinder body.