Description:FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[Refer Section 10, Rule 13]

TITLE OF INVENTION
A Cylinder Head Cover for an Internal Combustion Engine

APPLICANT
MAHINDRA & MAHINDRA LIMITED, an Indian company, having its address at Mahindra Research Valley, Mahindra World City, Plot No:41/1, Anjur P.O., Chengalpattu, Tamil Nadu – 603004, India

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.
FIELD OF THE INVENTION
[001] The present invention generally relates to an internal combustion engine. More particularly, the present invention relates to a cylinder head cover for the internal combustion engine.

BACKGROUND OF THE INVENTION
[002] Generally, in an internal combustion engine, blowby gases are generated during the operation of the engine. Blowby generally refers to the escape of combustion gases between piston and cylinder liner, from inside an engine's combustion chamber to the crankcase. During the combustion of compressed air-fuel mixture, some of the combustion gases are blown down to the crankcase due to tolerances and gaps in the piston, the piston rings and the cylinder liner. These blowby gases need to be vented out into the atmosphere so as to prevent build up of pressure inside the internal combustion engine.
[003] Conventionally, in IC engines, the blowby gas is released in two different ways i.e., an open loop system, where the blowby gases are released to the atmosphere via a pipe/hose, and a closed loop system, where the blowby gases are directed back into the engine to the intake manifold, using a PCV (Positive Crankcase Ventilation) system. The PCV system is designed to help manage blowby by venting gases from the crankcase to the intake manifold where they can be burned in the combustion process.
[004] The crankcase is used as a storage place for oil, usually in a pan or a sump located below the crankshaft. Vapours of oil can be found in the blowby gases, as these gases reach the crankcase. It is necessary that these oil vapours should not be recirculated back into the cylinders along with the blowby gases as this can make the gas-air mixture too combustible, equivalent to lowering the octane of the gasoline, which in some engines can degrade performance slightly and in older engines can even cause backfire when the gas-air mixture combusts prematurely. More specifically, in diesel IC engines, the combustion of the blowby gases along with the air-fuel mixture is not only detrimental to the health of the diesel IC engine, but also results in higher soot and ash emissions which are harmful for the environment as well as the diesel IC engine. The oil vapours can also coat the air intake with an oily film, gradually clogging the air flow over time.
[005] In order to prevent this from happening, an oil separator is used. The oil separator extracts the oil from the blowby gas before it's sent back to the intake manifold. It comes with a filter made of wire mesh in which, the oil droplets are trapped in the mesh while the air passes through it. The most effective filters are made up of microfibers, which can trap very small particles of oil. The lighter air molecules escape through the holes, while the heavier oil droplets fall all the way to the bottom, where they can be removed.
[006] However, the method of separating engine oil using the baffle, or the non-woven cloth does not sufficiently separate the oil and thus is not suitable to be used in consideration of latest emission regulations, which are getting gradually stronger. Furthermore, the external separator mounted on the head cover independently, increases complexity in packaging of connecting pipes and increases the boundary size of the IC engine, thereby making it difficult to design the engine to be compact.
[007] However, the usage of solely a separator may not sufficiently separate the oil from the blowby gases. Further, due to a high flow rate of oil vapours in the blowby gases, a larger sized separator is required to achieve sufficient separation to meet the emissions regulations, which leads to an increase in size of the engine. Further, due to the high flow rate, the separator is susceptible to clogging and may require frequent replacement. Furthermore, usage of any dedicated auxiliary separator before the separator to reduce the flow rate to the separator, leads to an increase in part count, as well as costs and complexity.
[008] Thus, there is a need in the art for a cylinder head cover for an internal combustion engine, which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[009] In one aspect, the present invention relates to a cylinder head cover for an internal combustion engine. The cylinder head has a first passage provided in the cylinder head cover. The first passage is defined by a side wall of the cylinder head cover and a first separator wall spaced apart from the side wall. The first passage extends vertically in the cylinder head cover. The first passage is configured to receive blowby gases generated in a cylinder body of the internal combustion engine. The cylinder head cover further has a second passage provided in the cylinder head cover. The second passage is defined by a top wall of the cylinder head cover and a second separator wall spaced apart from the top wall. The second passage extends horizontally from the first passage. The second passage is configured to receive blowby gases from the first passage, whereby flow of blowby gases through the first passage and the second passage causes separation of oil vapours from blowby gases, reducing flow rate of oil vapours in blowby gases being supplied to a gas-oil separator fluidly connected with the second passage.
[010] In an embodiment of the invention, the cylinder head cover has a slot for allowing entry of blowby gases into the first passage.
[011] In a further embodiment of the invention, the slot is provided at a lower end of the first passage.
[012] In an embodiment of the invention, the gas-oil separator is configured for separation of oil vapours from the blowby gases subsequent to the separation of oil vapours from the blowby gases in the first passage and the second passage.
[013] In a further embodiment of the invention, the cylinder head cover has a drain hole. The drain hole is configured to receive the separated oil from the blowby gases and transmit the oil to an oil sump of the internal combustion engine.
[014] In a further embodiment of the invention, the gas-oil separator is disposed on top of the cylinder head cover.
[015] In a further embodiment of the invention, the gas-oil separator has a deflector member having one or more baffle plates for separation of oil vapours from the blowby gases.
[016] In a further embodiment of the invention, the gas-oil separator has a diaphragm for filtering of the blowby gases after separation of oil vapours.

BRIEF DESCRIPTION OF THE DRAWINGS
[017] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a side view of a cylinder head cover for an internal combustion engine, in accordance with an embodiment of the invention.
Figure 2 illustrates a bottom view of the cylinder head cover, in accordance with an embodiment of the invention.
Figure 3 illustrates a perspective sectional view of the cylinder head cover for the internal combustion engine, in accordance with an embodiment of the invention.
Figure 4 illustrates a sectional view of the cylinder head cover for the internal combustion engine, in accordance with an embodiment of the invention.
Figure 5 illustrates another sectional view of the cylinder head cover for the internal combustion engine, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[018] The present invention relates to an internal combustion engine. More particularly, the present invention relates to a cylinder head cover for an internal combustion engine, wherein the cylinder head cover has multiple passages for allowing passage of blowby gases, whereby flow rate of oil vapours is reduced before blowby gases are supplied to a gas-oil separator.
[019] Figures 1 and 2 illustrate a side view and a bottom view of a cylinder head cover 100 of an internal combustion engine. The internal combustion engine of the present invention is typically used for a four wheeled vehicle or other multi-wheeled work vehicles as required. However, it should be understood that the internal combustion engine as illustrated may find its application on any other automotive or non-automotive application using an internal combustion engine. The cylinder head cover 100 is provided on top of a cylinder head of the internal combustion engine and the cylinder head cover 100 acts as a cover housing for housing one or more valves of the internal combustion engine. The cylinder head cover 100 is provided on the top of the cylinder head, which is in turn provided on top of a cylinder body and a crankcase of the internal combustion engine. Thus, the blowby gases generated in the combustion chamber in the cylinder body are accumulated in the crankcase, and thereafter rise up towards a space defined inside the cylinder head cover 100. Ventilation of these blowby gases is facilitated by the cylinder head cover 100 of the present invention.
[020] The blowby gases being generated in the internal combustion engine comprise oil vapours which need to be separated from the blowby gases before the blowby gases are fed back into the cylinder body for combustion or released into the atmosphere. To facilitate the separation of oil vapours from the blowby gases, as referenced in Figure 3, the cylinder head cover 100 of the present invention has a first passage 130 provided in the cylinder head cover 100. As illustrated, the first passage 130 is defined by a side wall 102 of the cylinder head cover 100 and a first separator wall 120. The first separator wall 120 is spaced apart from the side wall 102. In that, the first passage 130 extends vertically in the cylinder head cover 100. The first passage 130 is configured to receive blowby gases generated in the cylinder body of the internal combustion engine from the space inside the cylinder head cover 100. Herein, when the blowby gases enter the first passage 130, the blowby gases rise vertically in the first passage 130. In that, the oil vapours in the blowby gases come in contact with the first separator wall 120 and the side wall 102 of the cylinder head cover 100. This leads to condensation of the oil vapours thereby separating oil vapours from the blowby gases.
[021] Further, the cylinder head cover 100 has a second passage 140 provided therein. The second passage is defined by a top wall 104 of the cylinder head cover 100 and a second separator wall 124. The second separator wall 124 is spaced apart from the top wall 104. Further, the second passage 140 extends horizontally from the first passage 130 and the second passage 140 is configured to receive blowby gases from the first passage 130. Furthermore, the second passage 140 is configured to supply the blowby gases to a gas-oil separator 150 which is fluidly connected with the second passage 140. The gas-oil separator 150 is an external device specifically provided for separation of oil vapours from the blowby gases. Like the first passage 130, when the blowby gases enter the second passage 140 and move horizontally in the second passage 140, the oil vapours in the blowby gases come in contact with the top wall 104 of the cylinder head cover 100 and the second separator wall 124. This leads to condensation of the oil vapours thereby separating oil vapours from the blowby gases. Thus, the separation of the oil vapours from the blowby gases is achieved in the first passage 130 and the second passage 140. This leads to reduction of flow rate of oil vapours in blowby gases being supplied to the gas-oil separator 150, which is fluidly connected with the second passage 140.
[022] As a result of the first passage 130 extending vertically and the second passage 140 extending horizontally, the blowby gases are subjected to a change in travel direction while travelling from the first passage 130 to the second passage 140. This change in direction causes more oil vapours to be incident on the side wall 102, the top wall 104 as well as the first separator wall 120 and the second separator wall 124. As a result, condensation of the oil vapours to oil is increased. This condensed oil is then transmitted back to an oil sump of the internal combustion engine. By virtue of provision of the first passage 130 and the second passage 140, the amount of oil vapours reaching the gas-oil separator 150 is reduced as some oil vapours are already condensed to oil before reaching the gas-oil separator 150. This allows for the gas-oil separator to be subjected to lower flow rates of oil vapours, thereby eliminating the need for large gas-oil separators or the requirement of frequent replacement to meet the emission norms. In the present invention, an oil vapour flow rate of as low as 0.2g/hr into the gas-oil separator is achieved, without any additional serviceable element, such as a separate gas-oil separator.
[023] In an embodiment, the cylinder head cover 100 comprises a slot 122 for allowing entry of blowby gases into the first passage 130 from the space inside the cylinder head cover 100. In an embodiment, the slot 122 is provided at a lower end of the first passage 130.
[024] In an embodiment, the gas-oil separator 150 is configured for separation of oil vapours from the blowby gases subsequent to the separation of oil vapours from the blowby gases in the first passage 130 and the second passage 140. The flow of blowby gases in the present invention is illustrated in Figure 4, wherein as illustrated, the blowby gases flow into the space inside the cylinder head cover 100 (illustrated by dotted arrows in Figure 4). Thereafter, the blowby gases from this space enter the first passage 130 through the slot 122 on the first separator wall 120. The flow of blowby gases in the first passage 130 and subsequently the second passage 140 (illustrated by solid arrows in Figure 4) facilitates separation of oil vapours from the blowby gases. Accordingly, the oil vapours in the blowby gases flowing in the first passage 130 and second passage 140 condenses on contact with side wall 102, the top wall 104 as well as the first separator wall 120 and the second separator wall 124, thereby separating the oil vapours from the blowby gases. This condensed oil is then transmitted back to the oil sump through the cylinder head cover 100 assisted by gravity. Thereafter, the blowby gases are transmitted to the gas-oil separator 150 for further separation of oil vapours from the blowby gases. Thus, in effect, in an embodiment, the separation of oil vapours from the blowby gases in the first passage 130 and the second passage 140 is a first stage separation and the separation of oil vapours from the blowby gases in the gas-oil separator 150 is a second stage separation.
[025] As illustrated in the embodiment depicted in Figure 5, the cylinder head cover 100 comprises a drain hole 160. The drain hole 160 is configured to receive the separated oil from the blowby gases and transmit the oil to the oil sump of the internal combustion engine. In an embodiment, the drain hole 160 receives the separated oil from the gas-oil separator 150 for transmission to the oil sump.
[026] For facilitating the smooth flow of blowby gases into the gas-oil separator 150, the gas-oil separator 150 is disposed on top of the cylinder head cover 100. As illustrated in the embodiment depicted in Figure 5, the gas-oil separator 150 comprises a deflector member 152 having one or more baffle plates for separation of oil vapours from the blowby gases. The one or more baffle plates are provided for subjecting the blowby gases to a labyrinthine path. When the blowby gases enter the gas-oil separator 150 (illustrated by dotted arrows in Figure 5), the blowby gases come in contact with the baffle plates, which results in condensation of oil vapours in the blowby gases. Thereafter, the condensed oil (illustrated by black solid arrows in Figure 5) is transmitted towards the drain hole 160 and the separated blowby gases (illustrated by white solid arrows in Figure 5) travel towards a diaphragm 154 for filtering of the blowby gases after separation of oil vapours. The filtered blowby gases are then transmitted back to the internal combustion engine for combustion. Alternatively, as per requirement, a portion of the blowby gases are transmitted back to the internal combustion engine, and some portion of the blowby gases are released into the atmosphere.
[027] Advantageously, the present invention provides a cylinder head for an internal combustion engine wherein the provision of the first passage and the second passage allows for separation of oil vapours from the blowby gases before the blowby gases enter the gas-oil separator for further separation. This allows for oil vapours to be separated in the first passage and second passage as well as the gas-oil separator, thus reducing the flow rate of oil vapours into the gas-oil separator. This eliminates the requirement of using large sized separators and requirement for frequent replacement of the gas-oil separator, since the operational load on the gas-oil separator is reduced.
[028] Further, the present invention also eliminates the requirement of a separate auxiliary gas-oil separator prior to the gas-oil separator for achieving the reduction in flow rate, thus reducing part count, complexity and costs.
[029] The cylinder head cover of the present invention also ensures that emission norms can be met without increasing the size of the gas-oil separator, while also preventing pressure build up inside the crankcase.
[030] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.
, Claims:WE CLAIM:
1. A cylinder head cover (100) for an internal combustion engine, comprising:
a first passage (130) provided in the cylinder head cover (100), the first passage (130) being defined by a side wall (102) of the cylinder head cover (100) and a first separator wall (120) spaced apart from the side wall (102), the first passage (130) extending vertically in the cylinder head cover (100), the first passage (130) configured to receive blowby gases generated in a cylinder body of the internal combustion engine; and
a second passage (140) provided in the cylinder head cover (100), the second passage (140) being defined by a top wall (104) of the cylinder head cover (100) and a second separator wall (124) spaced apart from the top wall (104), the second passage (140) extending horizontally from the first passage (130), the second passage (140) configured to receive blowby gases from the first passage (130), whereby flow of blowby gases through the first passage (130) and the second passage (140) causes separation of oil vapours from blowby gases, reducing flow rate of oil vapours in blowby gases being supplied to a gas-oil separator (150) fluidly connected with the second passage (140).

2. The cylinder head cover (100) as claimed in claim 1, comprising a slot (122) for allowing entry of blowby gases into the first passage (130).

3. The cylinder head cover (100) as claimed in claim 2, wherein the slot (122) is provided at a lower end of the first passage (130).
4. The cylinder head cover (100) as claimed in claim 1, wherein the gas-oil separator (150) is configured for separation of oil vapours from the blowby gases subsequent to the separation of oil vapours from the blowby gases in the first passage (130) and the second passage (140).

5. The cylinder head cover (100) as claimed in claim 1, comprising a drain hole (160), the drain hole (160) being configured to receive the separated oil from the blowby gases and transmit the oil to an oil sump of the internal combustion engine.

6. The cylinder head cover (100) as claimed in claim 1, wherein the gas-oil separator (150) is disposed on top of the cylinder head cover (100).

7. The cylinder head cover (100) as claimed in claim 1, wherein the gas-oil separator (150) comprises a deflector member (152) having one or more baffle plates for separation of oil vapours from the blowby gases.

8. The cylinder head cover (100) as claimed in claim 1, wherein the gas-oil separator (150) comprises a diaphragm (154) for filtering of the blowby gases after separation of oil vapours.
Dated this 15th day of March 2024
MAHINDRA & MAHINDRA LIMITED
By their Agent & Attorney

(Janaksinh Jhala)
of Khaitan & Co
Reg No IN/PA-2193