FORM 2
THE PATENT ACT, 1970
(39 of 1970)
&
THE PATENTES RULES, 2005
COMPLETE SPECIFICATION (See section 10, rule 13)
1. TITLE OF THE INVENTION
"EXHAUST MANIFOLD FLANGE FOR AN ENGINE OF A VEHICLE"
2. APPLICANT(S)
(a) Name : MAHINDRA & MAHINDRA LIMITED
(b) Nationality : Indian Company registered under the provisions
of the Companies Act, 1956
(c) Address : R&D Center, Automotive Sector.
89, M.I.D.C.. Satpur, NASHIK-422 007 Maharashtra State, India
3. PREAMBLE OF THE DESCRIPTION

COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Exhaust manifold flange for an engine of a vehicle
Field of the invention
The present invention is related to an exhaust manifold flange suitable for an engine of automotive vehicle. More particularly the present invention is related to a flange of an exhaust manifold capable of accommodating thermal expansion of exhaust manifold flange of an engine.
Background of the invention
From the aspect of environmental protection and statutory requirements, automobile engines are recently required to have higher performance, increased fuel efficiency, and reduced exhaust gas emission. For this purpose, higher-power, higher-combustion temperature engines are developed, elevating exhaust gas temperatures. Accordingly, exhaust parts like exhaust manifold, turbochargers etc. are repeatedly heated and cooled in higher temperature regions than conventional ones. In addition because they are directly exposed to a high-temperature exhaust gas from engines, they come to be used in severe oxidation environment.
In many conventional engines, separate flanges are provided for each of the port, this leads to warp-age of cylinder head face and also has less strength to consider mechanical load of a turbocharger and the like. The slit in between each port on common flange and ports which are clamped individually on the cylinder head around the exhaust port are acting as separate flange. On conventional engines manifold mentioned as above leads to increase in center to center distance of engine which consequently increases overall length and in turn weight of an engine with consideration for design for assembly and thus making the engine bulky.

Provision for elongated holes for mounting for small thermal expansion but which are difficult for mass production for locating the port of manifold to port of head.
Use of slits with special Spacer block design over the flange which will be useful to separate port mounting bolts in 180 Degree angle. This design will not be suitable for temperature above 800°C as spacer will not allow for thermal expansion which leads to create thermal stresses. Secondly Assembly is complicated because one bolt has lug spacer while another bolt will be with different spacer to match common flange thickness. Bolt length requires higher space. Spacer with lug at its corner may create the stress while expansion and contraction which lead to crack the spacer.
Provision of cooling jacket over the exhaust manifold is bulky and complex design usually used for larger GAS engines. This design generally is not economical as additional material is required and casting process makes it difficult. This type of the manifold is not suitable for compact design which is used for automotive applications. It also gives additional load on water pump.
Japanese patent No. JP.7247836 discloses exhaust manifold to improve reliability by forming a slit on a part connecting installation flanges to each other, specifying difference between a bolt hole across the slit and an outer diameter of a bolt, and thereby preventing occurrence of deformation and cracks of parts of a manifold.
In this the slits are made in between the two ports and on flange, in which flange is mounted to cylinder head with opposite bolt across the port or with three bolts for each flange. That means each flange is attached to head separately and slit is not clamped by means of any clamping bolts or stud. So that in this design space required is more i.e. center to center distance between consecutive ports will be more hence this design is not compact design i.e. length of exhaust manifold and cylinder Head increased which will force to increase bore to bore center distance of crank bore. The relation between the bolt hole gap and slit is very difficult to

maintain in the production stage, which may lead to mismatch of port of manifold and cylinder head which in turn may causes resistance to exhaust gas flow and even after some hours of testing of an engine at severe conditions. In this concept, it is considered that there is uniform thermal expansion and contraction over entire flange but in actual condition thermal expansion will be different at different location depending combustion efficiency in each cylinder and its port design.
With respect to the high temperature strength, the exhaust equipment members should have not only high temperature tensile strength, but also high temperature yield strength, strength for suppressing thermal deformation (plastic deformation by compression) against compression stress generated under constrained conditions at high temperatures. Accordingly, the high temperature strength is represented by high temperature yield strength and high temperature tensile strength. The High temperature strength design is necessary in addition to sufficient space in the flange area to avoid the thermal constrains.
Also the exhaust manifold along with turbocharger are subjected to mechanical vibration, shock, etc. during the production process and assembling to engines, at the start of or during the driving of automobiles. The exhaust equipment members are also required to have sufficient strength to prevent cracking and breakage against these mechanical vibration and thermal shock. Therefore, it requires to hold the exhaust manifold flange firmly to cylinder head and this need to clamp the manifold across the slits.
Object of the invention
The main object of the present invention is to provide an exhaust manifold for egressing exhaust gases from a multi-cylinder internal combustion engine for accommodating thermal expansion of the exhaust manifold flange member of an engine.

Another object of the present invention is to provide an exhaust manifold for egressirtg exhaust gases from a multi-cylinder internal combustion engine to avoid thermal and thermo-fatigue cracking of exhaust manifold flange member of an engine.
Further object of the present invention is to provide an exhaust manifold for egressing exhaust gases from a multi-cylinder internal combustion engine to increase thermal cyclic life of the exhaust manifold of an engine.
Still further object of the present invention is to provide for a novel means for tightly securing the exhaust manifold flange member with cylinder head.
Still further object of the present invention is to avoid warpage of manifold flange member and cylinder head face thereby providing a leak-proof joint.
Statement of the invention
According to the present invention there is provided an exhaust manifold for egressing exhaust gases from a multi-cylinder internal combustion engine, the exhaust manifold comprising:
a first flange member secured to exhaust ports of the internal combustion engine.
a plurality of openings configured on the first flange member for securing thereof;
a plurality of conduits extending from the first flange member and configured to be secured to the exhaust port, the plurality of conduits converge to configure a passage; and
a second flange member configured over the passage, the second flange member capable of being securely connected with exhaust pipe(s) / turbocharger, characterized in that:

at least one opening of the plurality of the openings along the central portion of the first flange member is provided with a slit.
Typically, wherein the first flange member is secured to the exhaust ports of the internal combustion engine by copper coated clinched flanged boJts.
Typically, further comprises a gasket disposed between the first flange member and the engine exhaust side.
Typically, wherein the gasket is a metallic gasket or any other suitable material fulfilling the technical requirements therefore.
Typically, wherein the slit is vertical.
Typically, wherein the slit has a predetermined clearance depending upon temperature of exhaust manifold.
Typically, wherein the clearance of the at least one slit is uniform
Brief description of the drawings
The objects and features of the present invention will be more clearly understood from the following description of the invention taken in conjunction with the accompanying drawings, in which,
Figure 1 shows the perspective view of an exhaust manifold in accordance with the present invention;
Figure 2 shows isometric view of the exhaust manifold with details of a flange member of the exhaust manifold of figure 1;

Figure 3 and Figure 3A shows side and top view respectively of the exhaust manifold flange member of figure 2;
Figure 4 shows top view of an embodiment of the exhaust manifold in accordance with the present invention; and
Figure 5 shows top view of another embodiment of the exhaust manifold in accordance with the present invention.
Detail description of the invention
The foregoing objects of the invention are accomplished and the shortcomings associated with the prior art techniques and approaches are overcome by the present invention described in the preferred embodiment.
The present invention describes an exhaust manifold for egressing exhaust gases from a multi-cylinder internal combustion engine. The exhaust manifold is capable of accommodating thermal expansion caused due to the hot exhaust gases of the internal combustion engine. The exhaust manifold includes a first flange member, a second flange member and plurality of conduits. The first flange member is secured over the exhaust ports of the engine for coupling the conduits thereover for carrying the hot exhaust gases. The first flange member includes openings for bolting with the engine. The openings are provided with slit so that the first flange member accommodates thermal expansion caused due to the hot exhaust gases of the internal combustion engine.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Referring now to figures 1, 2, 3a & 3b. an exhaust manifold (100) for egressing exhaust gases from a multi-cylinder internal combustion engine (50) is illustrated, in accordance the present invention. The exhaust manifold (100) includes a first flange member (10). a second flange member (12), a plurality of conduits (14), and gasket (16). The first flange member (10) is secured over exhaust ports of the internal combustion engine (50). The first flange member (10) includes a plurality of openings (18) configured thereon for bolting with the engine (50). The gasket (16) is disposed between the first flange member (10) and the engine (50). The gasket (16) provided to seal the space between the first flange member (10) and the engine (50) for preventing leakage therebetween. In an embodiment, the gasket (16) is a metallic gasket. The plurality of conduits (14), for example the present invention is shown to include four conduits (14), extending from the first flange member (10) and configured to secure to the exhaust port. The conduits (14) further converge to configure a passage (20). The second flange member (12) is configured over the passage (20), which is capable of being coupled with the turbocharger / an exhaust pipe (not shown) of the engine (50).
A slit (22) configured on the openings (18) along a central portion of the openings configured on the first flange member (10), for example, the present invention is shown to include slits (22) on three openings (18a, 18b, & 18c) (refer figure 2 &3). The slits (22) enable the first flange member (10) of the exhaust manifold (100) to accommodate thermal expansion, thereby increasing the life thereof. In the preferred embodiment, clearance of slit shall be in the range of 1.2 mm to 3.0 mm for all the slits, however, optimized results shall be at 2.5 mm. The plurality of openings (18) configured on the first flange member (10) are secured to the engine preferably by bolted by copper coated clinched flanged bolts. The copper coated clinched flanged bolts are special bolts with clinching operation once fitted avoid loosening of the bolts by thermal/vibration phenomenon, copper coating helps to dissipate the heat at faster rate.

In other embodiment the slit (22) at openings (18a) and (18c) are of equal size, in the range of 1.2mm to 3.0 mm in order to facilitate easiness of making / manufacturing of slit (22) operations during the course of production. The slits (22) are formed on the openings of the first flange member (10) by abrasive parting wheel or flex type rotary / reciprocating blade or milling operation or combination of thereof. Due to these slits (22), the thermal life cycle of the first flanged member (10) of the exhaust manifold (100) is improved to successfully accommodate high thermal stresses.
In an embodiment, the second flange member (12) is configured away from the centre of the exhaust manifold (100) as shown in figure 4. In another embodiment, the second flange member (12) is configured on side portion of the exhaust manifold (100) as shown in figure 5.
It is to be understood that the present invention is not limited in its application to the details of the construction and to the arrangements of the components as mentioned in the above description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, the terminologies used herein are for the purpose of description and should not be regarded as limiting.
Advantages of the exhaust manifold (100) present invention:
It is low in cost and easy to machining / manufacturing.
The available space on the first flange member (10) is managed and utilized effectively to avoid its thermo fatigue cracking.
As the slit (22) is clamped by nut and bolt, the centre to centre distance of the ports is reduced to lead the design of the engine to be compact and handy. The

clamping over the slits (22) also helps to reduce the warp-page of the entire the first flange member (10) which makes joint leak proof.
Detailed description of the preferred embodiment is provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter.

We Claim;
1. An exhaust manifold for egressing exhaust gases from a multi-cylinder internal combustion engine, the exhaust manifold comprising:
a first flange member secured to exhaust ports of the internal combustion engine,
a plurality of openings configured on the first flange member for securing thereof;
a plurality of conduits extending from the first flange member and configured to be secured to the exhaust port, the plurality of conduits converge to configure a passage; and
a second flange member configured over the passage, the second flange member capable of being securely connected with exhaust pipe(s) / turbocharger, characterized in that:
at least one opening of the plurality of the openings along the central portion of the first flange member is provided with a slit.
2. The exhaust manifold as claimed in claim 1, wherein the first flange member is secured to the exhaust ports of the internal combustion engine by copper coated clinched flanged bolts.
3. The exhaust manifold as claimed in claim 1, further comprises a gasket disposed between the first flange member and the engine exhaust side.
4. The exhaust manifold as claimed in claim 3, wherein the gasket is a metallic gasket or any other suitable materia! fulfilling the technical requirements therefore.
5. The exhaust manifold as claimed in claim 1, wherein the slit is vertical.

6. The exhaust manifold as claimed in claim 1, wherein the slit has a predetermined clearance depending upon temperature of exhaust manifold.
7. The exhaust manifold as claimed in claim 6, wherein the clearance of the at least one slit is uniform.
8. The exhaust manifold substantially as described in the description with reference to the accompanying drawings.