Claims:WE CLAIM:
1. A cylinder cover head (100) of an internal combustion engine (12), comprising:
an oil separator (110) disposed on an inner surface of the cylinder cover head (100) for separating oil mist from blow-by gases, the oil separator (110) having a plurality of channels for flow of blow-by gases defined by one or more ribs (112) such that the oil mist condenses on contact with the one or more ribs (112);
a partition plate (120) disposed below the oil separator (110) for isolating the oil separator (110) within the cylinder cover head (100); and
at least one slot (130) disposed on an upper surface of the cylinder cover head (100) for visual inspection of a valvetrain (160) from outside the cylinder cover head (100).

2. The cylinder cover head (100) as claimed in claim 1, wherein the one or more ribs (112) of the oil separator (110) comprise 1+n ribs (112), n being a natural number.

3. The cylinder cover head (100) as claimed in claim 2, wherein n is chosen based on at least pressure in an intake manifold of the engine (12), ideal gas constant, and temperature and volume in the intake manifold.

4. The cylinder cover head (100) as claimed in claim 1, wherein the plurality of channels of the oil separator (110) are defined in a labyrinth maze structure by the one or more ribs (112).

5. The cylinder cover head (100) as claimed in claim 1, wherein the one or more ribs (112) are slanted such that the condensed oil trickles along the slant, and is collected in an oil sump through the partition plate (120), assisted by gravity.

6. The cylinder cover head (100) as claimed in claim 1, wherein the slots (130) are covered by a semi-transparent material to allow for visual inspection of the valvetrain (160) from outside the cylinder cover head (100).

7. The cylinder cover head (100) as claimed in claim 1, wherein the slot (130) is configured for visual inspection of the valvetrain (160) from outside the cylinder cover head (100) when the engine (12) is in a running condition.

8. The cylinder cover head (100) as claimed in claim 1, wherein the slot (130) is configured for visual inspection of the valvetrain (160) from outside the cylinder cover head (100) when the engine (12) is in an off condition.

9. The cylinder cover head (100) as claimed in claim 1, comprising a gasket (150) disposed between the oil separator (110) and the partition plate (120) to prevent oil leakage at the partition plate (120).

10. A vehicle (10), comprising:
an internal combustion engine (12); and
a cylinder cover head (100) of the internal combustion engine (12) having:
an oil separator (110) disposed on an inner surface of the cylinder cover head (100) for separating oil mist from blow-by gases, the oil separator (110) having a plurality of channels for flow of blow-by gases defined by one or more ribs (112) such that the oil mist condenses on contact with the one or more ribs (112);
a partition plate (120) disposed below the oil separator (110) for isolating the oil separator (110) within the cylinder cover head (100); and
at least one slot (130) disposed on an upper surface of the cylinder cover head (100) for visual inspection of a valvetrain (160) from outside the cylinder cover head (100).

11. The vehicle (10) as claimed in claim 1, wherein the cylinder cover head (100) comprises the slot (130) disposed on the upper surface of the cylinder cover head (100) for visual inspection of the valvetrain (160) from outside the cylinder cover head (100) when the engine (12) is in a running condition.

12. The vehicle (10) as claimed in claim 1, wherein the cylinder cover head (100) comprises the slot (130) disposed on the upper surface of the cylinder cover head (100) for visual inspection of the valvetrain (160) from outside the cylinder cover head (100) when the engine (12) is in an off condition.

13. A method (200) for determining number of ribs (112) for an oil separator (112) in a cylinder cover head (100) of an internal combustion engine (12), the method comprising the steps of:
receiving a plurality of real-time input parameters captured by a plurality of sensors located in the engine (12);
determining a first crank angle (θ) by the received plurality of real-time input parameters;
determining pressure in a crankcase (P), flow rate (a), clearance gap (C) between piston ring and cylinder liner, based on the first crank angle (θ) and mass flow values for every piston ring interface iteratively;
determining free volume (V) of the crankcase and negative pressure arising in an intake manifold;
determining mass of blow-by gas (M) based on the determined pressure (P) in the crankcase and a predetermined mass flow rate formula, temperature (T0), and clearance gap (C) between the piston ring and a cylinder liner for every piston ring iteration;
determining area of contact surface (Ac) of the ribs (112) based on geometry parameters of the piston, free volume (V) of the crankcase and determined mass of blow-by gas (M);
determining final mass (Mf) of blow-by gas based on area of contact surface (Ac) of the ribs (112) and determined mass (M) of blow-by gas for every piston ring iteration; and
determining number (N) of ribs (112) based on area of contact surface (Ac) of ribs (112), final mass (Mf) of blow-by gases and a predetermined oil-mist and blow by gases separation coefficient (K).
, Description:FIELD OF THE INVENTION
[001] The present invention relates to a cylinder cover head of an internal combustion engine.

BACKGROUND OF THE INVENTION
[002] In conventional motor vehicles, blow-by is a commonly occurring phenomenon. Due to heat generated in the engine, the oil present in the crankcase evaporates and gets mixed with the blow-by gases as mist. The blow-by gases along with the oil mist are passed through a Positive Crankcase Ventilation (PCV) system back into the intake manifold. This results in the blow-by gases being mixed with air-fuel mixture and being burnt in combustion chamber, which not only hampers the efficiency of the engine, but also increases the oil consumption.
[003] In existing methods of separation of oil from the blow-by gases, the blow-by gases are made to pass through a separator in a cylinder head cover before allowing their entry into the intake manifold. The oil from the separator is then sent back to a unit which holds the excess amount of oil through a drain device, and eventually to the oil sump. The separation of oil from the blow-by gases depends upon various pre-defined parameters such as length of oil path, width of the ribs, pressure inside the oil separator etc. Existing separators are known to have a lower efficiency in terms of separation of oil. Addition of a separator to an already bulky cylinder head adds to the overall weight of the vehicle, reducing the fuel economy of the vehicle.
[004] Further, in existing cylinder head covers, there is no provision for visual inspection or examination of problems in the cylinder head cover while the engine is in a running condition. The problems in the engine, valve train parts or the cylinder head can only be diagnosed once the engine is in an off condition, and the cylinder head cover is removed. The requirement of engine needing to be in an off condition and opening of the cylinder head cover makes diagnosis a cumbersome and time-consuming process. Further, diagnosis of engine faults cannot be done in real time.
[005] Thus, there is a need in the art for a cylinder cover head for an internal combustion engine which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[006] In one aspect, the present invention is directed at a cylinder cover head of an internal combustion engine. The cylinder cover head has an oil separator disposed on an inner surface of the cylinder cover head for separating oil mist from blow-by gases. The oil separator has a plurality of channels for flow of blow-by gases that are defined by one or more ribs such that the oil mist condenses on contact with the one or more ribs. The cylinder cover head further has a partition plate disposed below the oil separator for isolating the oil separator within the cylinder cover head, and at least one slot disposed on an upper surface of the cylinder cover head for visual inspection of a valvetrain from outside the cylinder cover head.
[007] In an embodiment of the invention, the one or more ribs of the oil separator have 1+n ribs, n being a natural number. In an embodiment, n is chosen based on at least pressure in an intake manifold of the engine, ideal gas constant, and temperature and volume in the intake manifold.
[008] In another embodiment of the invention, the plurality of channels of the oil separator are defined in a labyrinth maze structure by the one or more ribs. In an embodiment, the one or more ribs are slanted such that the condensed oil trickles along the slant and is collected in an oil sump through the partition plate, assisted by gravity.
[009] In another embodiment of the invention, the slots are covered by a semi-transparent material to allow for visual inspection of the valvetrain from outside the cylinder cover head.
[010] In a further embodiment of the invention, the slot is configured for visual inspection of the valvetrain from outside the cylinder cover head when the engine is in a running condition. In an embodiment, the slot is configured for visual inspection of the valvetrain from outside the cylinder cover head when the engine is in an off condition.
[011] In a further embodiment of the invention, the cylinder cover head has a gasket disposed between the oil separator and the partition plate to prevent oil leakage at the partition plate.
[012] In another aspect, the present invention relates to a vehicle having an internal combustion engine and a cylinder cover head for the internal combustion engine. The cylinder cover head has an oil separator disposed on an inner surface of the cylinder cover head for separating oil mist from blow-by gases. The oil separator has a plurality of channels for flow of blow-by gases that are defined by one or more ribs such that the oil mist condenses on contact with the one or more ribs. The cylinder cover head further has a partition plate disposed below the oil separator for isolating the oil separator within the cylinder cover head, and at least one slot disposed on an upper surface of the cylinder cover head for visual inspection of a valvetrain from outside the cylinder cover head.
[013] In an embodiment of the invention, the slot is configured for visual inspection of the valvetrain from outside the cylinder cover head when the engine is in a running condition. In an embodiment, the slot is configured for visual inspection of the valvetrain from outside the cylinder cover head when the engine is in an off condition.
[014] In yet another aspect, the present invention relates to a method for determining number of ribs for an oil separator in a cylinder cover head of an internal combustion engine. The method steps involved are: receiving a plurality of real-time input parameters captured by a plurality of sensors located in the engine; determining a first crank angle by the received plurality of real-time input parameters; determining pressure in a crankcase, flow area, clearance gap between piston ring and cylinder liner, based on the first crank angle and mass flow values for every piston ring interface iteratively; determining free volume of the crankcase and negative pressure arising in an intake manifold; determining mass of blow-by gas based on the determined pressure in the crankcase and a predetermined mass flow rate formula, temperature, and clearance gap between the piston ring and a cylinder liner for every piston ring iteration; determining area of contact surface of the ribs based on geometry parameters of the piston, free volume of the crankcase and determined mass of blow-by gas; determining final mass of blow-by gas based on area of contact surface of the ribs and determined mass of blow-by gas for every piston ring iteration; and determining number of ribs based on area of contact surface of ribs, final mass of blow-by gases and a predetermined oil-mist and blow by gases separation coefficient.

BRIEF DESCRIPTION OF THE DRAWINGS
[015] 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 right-side view of an exemplary motor vehicle, in accordance with an embodiment of the invention.
Figure 2 illustrates a bottom view of a cylinder cover head for an internal combustion engine, in accordance with an embodiment of the invention.
Figure 3 illustrates a bottom view of an oil separator in the cylinder cover head, in accordance with an embodiment of the invention.
Figure 4 illustrates an exploded perspective view of the cylinder cover head, in accordance with an embodiment of the invention.
Figure 5 illustrates a bottom view of the cylinder cover head with one or more slots, in accordance with an embodiment of the invention.
Figure 6 illustrates a top perspective view of the cylinder cover head, in accordance with an embodiment of the invention.
Figure 7 illustrates a perspective sectional view of the cylinder cover head, in accordance with an embodiment of the invention.
Figure 8 illustrates another perspective sectional view of the cylinder cover head, in accordance with an embodiment of the invention.
Figure 9 illustrates a side sectional view of the cylinder cover head, in accordance with an embodiment of the invention.
Figure 10 illustrates a method for determining number of ribs in the oil separator of the cylinder cover head, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[016] The present invention relates to a cylinder cover head of an internal combustion engine. More particularly, the present invention relates to a cylinder cover head with an oil separator.
[017] Figure 1 illustrates an exemplary motor vehicle 10, in accordance with an embodiment of the invention. The motor vehicle 10 comprises an Internal combustion engine 12 that is vertically disposed. Preferably, the Internal combustion engine 12 is a single-cylinder type Internal combustion engine. The motor vehicle 10 comprises a front wheel 14, a rear wheel 16, a frame member, a seat assembly 18 and a fuel tank 44. The frame member includes a head pipe 22, a main tube 24, a down tube (not shown), and seat rails (not shown). The head pipe 22 supports a steering shaft (not shown) and two telescopic front suspensions 26 (only one shown) attached to the steering shaft through a lower bracket (not shown). The two telescopic front suspensions 26 support the front wheel 14. The upper portion of the front wheel 14 is covered by a front fender 28 mounted to the lower portion of the telescopic front suspension 26 at the end of the steering shaft. A handlebar 30 is fixed to upper bracket not shown and can rotate to both sides. A head light 32, a visor guard (not shown) and instrument cluster (not shown) is arranged on an upper portion of the head pipe 22. The down tube is located in front of the Internal combustion engine 12 and extends slantingly downward from head pipe 22. The main tube 24 of the frame member is located above the Internal combustion engine 12 and extends rearward from head pipe 22. The Internal combustion engine 12 is mounted at the front to the down tube and a rear of the Internal combustion engine 12 is mounted at the rear portion of the main tube 24. In an embodiment, the Internal combustion engine 12 is mounted vertically, with a cylinder block extending vertically above a crankcase. In an alternative embodiment, the Internal combustion engine 12 is mounted horizontally (not shown) with the cylinder block extending horizontally forwardly from the crankcase. In an embodiment, the cylinder block is disposed rearwardly of the down tube.
[018] The fuel tank 44 is mounted on the horizontal portion of the main tube 24. Seat rails are joined to main tube 24 and extend rearward to support a seat assembly 18. A rear swing arm 34 is connected to the frame member to swing vertically, and the rear wheel 16 is connected to rear end of the rear swing arm 34. Generally, the rear swing arm 34 is supported by a mono rear suspension 36 (as illustrated in the present embodiment) or through two suspensions on either side of the motor vehicle 10. A taillight unit 33 is disposed at the end of the motor vehicle 10 and at the rear of the seat assembly 18. A grab rail 35 is also provided on the rear of the seat rails. The rear wheel 16 arranged below the seat assembly 18 rotates by the driving force of the Internal combustion engine 12 transmitted through a chain drive (not shown) from the Internal combustion engine 12. A rear fender 38 is disposed above the rear wheel 16.
[019] Further, an exhaust pipe 40 of the vehicle extends vertically downward from the Internal combustion engine 12 up to a point and then extends below the Internal combustion engine 12, longitudinally along the vehicle length before terminating in a muffler 42. The muffler 42 is typically disposed adjoining the rear wheel 16.
[020] Figure 2 illustrates a bottom view of a cylinder cover head 100 of the internal combustion engine 12. The cylinder cover head 100 covers a cylinder head of the crankcase of the engine 12. The cylinder cover head 100 serves to seal the crankcase of the engine 12 from the outside of the engine 12, thus ensuring that no gases from the engine 12 are leaked outside the engine 12. In an embodiment, the cylinder cover head 100 is made of a light weight material such as engineering plastic or a magnesium alloy. The cylinder cover head 100 is configured to receive blow-by gases from a Positive Crankcase Ventilation (PCV) (not shown) in the engine 12. The PCV transmits the blow-by gases from the crankcase to the cylinder cover head 100 via an intake manifold (not shown). The blow-by gases then get mixed with air-fuel mixture and is then sent to a combustion chamber in the engine 12. The blow-by gases have oil mist, which requires separation before the blow-by gases can be sent to the combustion chamber.
[021] To facilitate this, as illustrated in Figure 3, the cylinder cover head 100 has an oil separator 110 disposed on an inner surface of the cylinder cover head 100 for separating oil mist from the blow-by gases. The oil separator 110 has a plurality of channels for flow of the blow-by gases. The channels are defined by one or more ribs 112 such that the oil mist condenses on contact with the one or more ribs 112. In an embodiment, the plurality of channels of the oil separator 110 are defined in a labyrinth maze structure by the one or more ribs 112. As the blow-by gases with the oil mist pass through these channels as represented by the arrows, the one or more ribs 112 create areas of localised high velocity within the channels. The oil mist in the blow-by gases gets trapped in these areas of high localised velocity, and resultantly condense on contact with the ribs 112. This condensed oil is then re-introduced in an oil sump in the crankcase via a drain device (not shown). Further, the blow-by gases separated from the oil mist are sent to the engine 12 via a breather pipe 140 positioned at an end of the oil separator 110. The blow-by gases separated from the oil, travel through the breather pipe 140 to an air filter and are then sent to the combustion chamber for combustion.
[022] As illustrated in Figure 4, the cylinder cover head 100 further has a partition plate 120 disposed below the oil separator 110 for isolating the oil separator 110 within the cylinder cover head 100. The partition plate 120 ensures that the oil being separated in the oil separator 110 is not leaked into other parts of the crankcase in the engine 12. The cylinder cover head 100 further comprises a gasket 150 that is disposed between the oil separator 110 and the partition plate 120. The gasket 150 seals the joint between the oil separator 110 and the partition plate 120, thereby preventing oil leakage at the partition plate 120.
[023] As further illustrated in Figure 4, and referenced in Figure 3, the one or more ribs 112 are slanted such that the condensed oil, which has been separated from the blow-by gases trickles along the slant. The trickled oil is then collected in the oil sump through the partition plate 120 and the drain device, assisted by gravity. As mentioned earlier, the cylinder cover head 100 has one or more ribs 112. In an embodiment, the one or more ribs 112 comprise 1+n ribs 112, with n being a natural number. The natural number n for the number of ribs 112 is chosen by a method 200 (shown in Figure 10) based on at least pressure in the intake manifold of the engine 12, ideal gas constant, and temperature and volume in the intake manifold, as explained later in the description.
[024] As illustrated in Figure 5, and referenced in Figures 3 and Figure 4, the cylinder cover head 100 has at least one slot 130 disposed on an upper surface of the cylinder cover head 100 for visual inspection of a valvetrain 160 (shown in Figure 7) from outside the cylinder cover head 100. In an embodiment, the slot 130 is configured for visual inspection of the valvetrain 160 from outside the cylinder cover head 100 when the engine 12 is in a running condition. The slot 130 is also configured for visual inspection of the valvetrain 160 from outside the cylinder cover head 100 when the engine 12 is in an off condition. Such a configuration allows for inspection of the valvetrain 160 and engine diagnosis under all engine conditions.
[025] In the embodiment illustrated in Figure 5, the cylinder cover head 100 has five slots 130A, 130B, 130C, 130D, 130E disposed in different positions on the upper surface of the cylinder cover head 100 for visual inspection of components of the valvetrain 160 from different positions. In an embodiment, the slots 130 are covered by a semi-transparent material to allow for visual inspection of the valvetrain 160 from outside the cylinder cover head 100.
[026] As illustrated in Figure 9, and referenced in Figure 7 and Figure 8, the valvetrain 160 comprises of a cam sprocket valvetrain 160 having a cam sprocket 162, a camshaft 164 and at least one bearing 166, all of which can be subjected to visual inspection through the slots 130. In an embodiment, the one or more slots 130 on different positions on the cylinder cover head 100 allow for specific visual inspection of the cam sprocket 162, the camshaft 164, and the bearing 166 during all engine conditions.
[027] In another aspect, the present invention relates to a vehicle 10 with an internal combustion engine 12, that has a cylinder cover head 100 with an oil separator 110, a partition plate 120 and at least one slot 130 as explained hereinbefore.
[028] In another aspect, the present invention relates to a method 200 for determining number of ribs 112 for an oil separator 110 in a cylinder cover head 100 of an internal combustion engine 12, as referenced above. Figure 10 illustrates the method steps involved in the method 200 for determining number of ribs 112 in the cylinder cover head 100. As illustrated in the Figure, at step 20A, a plurality of real-time input parameters which are captured by a plurality of sensors located in the engine 12, are received. The real-time input parameters comprise of temperature and pressure parameters. Herein, the temperature parameters are obtained from a thermocouple and pressure parameters are obtained from pressure sensors. At step 20B, a first crank angle (θ) is determined based on the received plurality of real-time input parameters at step 20A. At step 20C, pressure in a crankcase (P), flow area (a), clearance gap (C) between piston ring and cylinder liner, are iteratively determined based on the first crank angle (θ) and mass flow values, for every piston ring interface.
[029] At step 20D, free volume (V) of the crankcase and negative pressure arising in an intake manifold of the engine 12 is determined. At step 20E, mass of blow-by gas is determined for every piston ring iteration, based on the determined pressure (P) in the crankcase at step 20D and a predetermined mass flow rate formula, temperature (T0), and clearance gap (C) between the piston ring and a cylinder liner. The mass flow (M) of blow-by gases for every piston ring iteration is given as ((Pressure (P) in cylinder * clearance gap (C))/ temperature (T0)). In an embodiment, the mass of blow-by gases is measured in kilogram per second (kg/s). In another embodiment, the mass of blow-by gases is measured in litres per minute (lpm). A mass flow rate parameter (MFP) for every iteration would be calculated as Mass of blow-by gas (M) divided by mass of injected fuel (mif).
[030] At step 20F, area of contact surface (Ac) of the ribs 112 as Length (L) of the rib multiplied by breadth (B) of the ribs, is determined based on geometry parameters of the piston, free volume of the crankcase and determined mass of blow-by gas at step 20E. At step 20G, final mass of blow-by gas (Mf) is determined based on area of contact surface of the ribs 112 calculated at step 20F and determined mass of blow-by gas for every piston ring iteration calculated at step 20D, wherein Mf = ΣM. Herein, the relationship of the final mass (Mf) of the blow-by gases across the crankcase can be understood as (ΔP(across the crankcase)*V = (Mf/Molmass of fuel)*R*ΔT).
[031] At step 20H, number (N) of ribs 112 are determined based on area of contact surface of ribs 112 determined at step 20F, final mass of blow-by gases and a predetermined oil-mist and blow by gases separation coefficient. The number of ribs 112 is determined as (N= Mf/(ΔP*(Ac)*(L)*(K))), wherein ΔP denotes pressure gradient across the rib section, and K denotes the oil-mist and blow by gases separation coefficient.
[032] Advantageously, the present invention provides a cylinder cover head with an oil separator that ensures a high efficiency in separation of oil mist from the blow-by gases. The efficient oil separation, in turn ensures better emission parameters for the vehicle. The present invention also provides a cylinder cover head which is lightweight, thus providing better fuel economy and reduction in manufacturing and running costs.
[033] Further, the one or more slots on the cylinder cover head for the visual inspection of the valvetrain ensure that the valvetrain can be visually inspected without opening the cylinder cover head and under both engine running and engine switched off conditions. The ability to visually inspect the valvetrain in an engine running conditions provides better serviceability and real time engine diagnosis. The semi-transparent material used to cover the slots also provide for better aesthetics.
[034] Furthermore, the partition plate and the gasket prevent any leakage from the oil separator into the engine. In addition, the oil separator in the present invention also facilitates enhancement in the performance of the PCV of the engine, which in turn ensures better cooling characteristics in the engine.
[035] 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.

List of Reference Numerals
10: Saddle Type Vehicle
12: Internal combustion engine
14: front wheel
16: rear wheel
18: seat assembly
22: head pipe
24: main tube
26: telescopic front suspensions
30: handlebar
32: head light
33: tail light
34: swing arms
35: grab rail
36: mono rear suspension
38: rear fender
40: exhaust pipe
42: muffler
44: fuel tank
100: cylinder cover head
110: oil separator
112: ribs
120: partition plate
130: slot
140: breather pipe
150: gasket
160: valvetrain
162: cam sprocket
164: camshaft
166: bearing
a: flow area (m2)
B: Breadth of the ribs
C: clearance gap (m)
K: oil-mist and blow by gases separation coefficient
L: Length of rib (m)
MFP: mass flow parameter
M: mass flow rate (kg/s)
mif: mass of injected fuel
Mf: final mass of blow-by gases (kg/s)
N: Number of ribs
P: pressure (N/m2)
R: gas constant (J/kg K)
T0: temperature of the gases in the combustion chamber
Θ: crank angle
V: volume of crankcase (m3)
Ac: Area of contact surface of ribs (m2)